Ljubljana, Slovenia
Ljubljana, Slovenia

The University of Ljubljana is the oldest, largest, and internationally best ranked university in Slovenia, being among the first 500 or the first 3% of the world's best universities according to the ARWU. With over 63,000 enrolled undergraduate and graduate students, it is also among the largest universities in Europe. Wikipedia.

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University of Ljubljana and University of Montenegro | Date: 2017-04-12

The present invention relates to a method for image processing comprising compressive sensing-based image filtering and intelligent removal of noise from images, and for image reconstruction/decompression, and to a device for carrying out said method. The system enables reconstruction of a natural image missing a great part of useful information. The method further enables filtering and removing of two types of noise from damaged natural images, that is a Gaussian noise and an impulse noise.

Isabella O.,Technical University of Delft | Krc J.,University of Ljubljana | Zeman M.,Technical University of Delft
Applied Physics Letters | Year: 2010

Substrates with a modulated surface texture were prepared by combining different interface morphologies. The spatial frequency surface representation method is used to evaluate the surface modulation. When combining morphologies with appropriate geometrical features, substrates exhibit an increased scattering level in a broad wavelength region. We demonstrate that the improved scattering properties result from a superposition of different light scattering mechanisms caused by the different geometrical features integrated in a modulated surface texture. © 2010 American Institute of Physics.

Kejzar N.,University of Ljubljana
Studies in Classification, Data Analysis, and Knowledge Organization | Year: 2010

Web of Science (WoS) is a database that provides information about current and past articles published in over 10,000 of the most prestigious, high impact research journals in the world from year 1970 on. A file with full information - records about selected articles - can be downloaded and further analyzed. We collected from WoS complete records on articles fromJournal of Classification, articles citing these articles, and articles in WoS cited by them at least 10 times. A special program WoS2Pajek was developed for converting such data into Pajek network files. The citation network between articles, networks of articles × authors, articles × keywords, articles × journals, and the partition according to publication year were obtained from the data. These networks were analyzed in order to identify the most important authors, works and topics that have been involved in the field in the last decades. © Springer-Verlag Berlin Heidelberg 2010.

Starcevic J.N.,University of Ljubljana | Petrovic D.,University of Ljubljana
Cardiovascular and Hematological Agents in Medicinal Chemistry | Year: 2013

The prognostic importance of large artery structure and function in relation to cardiovascular morbidity and mortality, together with the identification of new genetic risk factors have been two major areas of investigation in recent years. Carotid intima-media thickness (CIMT), as measured by B-mode ultrasound, is a surrogate marker for atherosclerosis and can be used to detect an accelerated disease process as well as subclinical disease. However, the genetic basis for CIMT variation is almost unknown. Cardiovascular genetics has led to numerous clinical studies generally focused on only one candidate gene and were frequently conducted in subjects with cardiovascular diseases and/or taking drugs that could affect CIMT. Pharmacogenetics is the study of the effect of a medication as it relates to single or defined sets of genes. An important goal of pharmacogenetics in cardiovascular disorders is to integrate the two (drugs plus genes) so that true personalized therapy can be delivered. In this paper, we will discuss the interaction between genes involved in lipid metabolism and statin therapy that affects intermediate phenotype (plasma lipid levels) and CIMT in patients with type 2 diabetes. © 2013 Bentham Science Publishers.

Schara R.,University of Ljubljana
Journal of the International Academy of Periodontology | Year: 2013

The aim of the study was to evaluate the prevalence of periodontal pathogens Aggregatibacter actinomycetemcomitans, Porphyromonas gingivalis, Prevotella intermedia, Tannerella forsythia and Treponema denticola in subgingival plaque collected at different probing depths of type 1 diabetes patients with periodontal disease in correlation to metabolic control. Twenty-one patients 40 to 50 years old were included in the study. In each patient blood samples were taken for the evaluation of HbA1c level and subgingival plaque samples were taken with paper points from the two deepest pockets. The presence of five periodontal pathogens was detected by multiplex polymerase chain reaction. The results of 38 plaque samples showed that T. forsythia was found in 48% followed by T. denticola in 31%, P. gingivalis in 26%, P. intermedia in 9% and A. actinomycetemcomitans in 7%. T. forsythia and T. denticola were the most frequent combination of periodontal pathogens found in the same sample. The serum level of HbA1c in nine patients where T. forsythia was detected (7.5 +/- 1.4%) was significantly higher (F-test, p = 0.001) than in 12 patients where T. forsythia was not detected (6.8 +/- 0.5%). Similarly, the serum level of HbA1c was significantly higher (F-test, p = 0.001) in eight patients where T. denticola was detected (7.5 +/- 1.8%) compared to the 13 patients where T. denticola was not detected (7.0 +/- 0.5%). No such correlation was found for P. gingivalis, P. intermedia or A. actinomycetemcomitans. We conclude that T. forsythia and T. denticola are most frequently found in subgingival plaque samples of type 1 diabetic patients and these findings correlate with poorer metabolic control of diabetes.

Vodusek D.B.,University of Ljubljana
International Urogynecology Journal and Pelvic Floor Dysfunction | Year: 2011

Introduction Clinical neurophysiological methods remain interesting research tools in urogynecology; their diagnostic role in the individual "pelvic f loor" patient is, however, minor. Conclusion The methods are diagnostically useful particularly in patients suspected to have a lesion involving the sphincters or the peripheral sacral nervous system, the diagnosis of which will influence management decisions or have prognostic or medicolegal relevance. Most helpful tests are the concentric needle EMG and bulbocavernosus reflex testing. © 2011 The International Urogynecological Association.

Pirkmajer S.,University of Ljubljana | Chibalin A.V.,Karolinska Institutet
American Journal of Physiology - Endocrinology and Metabolism | Year: 2016

keletal muscle contains one of the largest and the most dynamic pools of Na,K-ATPase (NKA) in the body. Under resting conditions, NKA in skeletal muscle operates at only a fraction of maximal pumping capacity, but it can be markedly activated when demands for ion transport increase, such as during exercise or following food intake. Given the size, capacity, and dynamic range of the NKA pool in skeletal muscle, its tight regulation is essential to maintain whole body homeostasis as well as muscle function. To reconcile functional needs of systemic homeostasis with those of skeletal muscle, NKA is regulated in a coordinated manner by extrinsic stimuli, such as hormones and nerve-derived factors, as well as by local stimuli arising in skeletal muscle fibers, such as contractions and muscle energy status. These stimuli regulate NKA acutely by controlling its enzymatic activity and/or its distribution between the plasma membrane and the intracellular storage compartment. They also regulate NKA chronically by controlling NKA gene expression, thus determining total NKA content in skeletal muscle and its maximal pumping capacity. This review focuses on molecular mechanisms that underlie regulation of NKA in skeletal muscle by major extrinsic and local stimuli. Special emphasis is given to stimuli and mechanisms linking regulation of NKA and energy metabolism in skeletal muscle, such as insulin and the energy-sensing AMP-activated protein kinase. Finally, the recently uncovered roles for glutathionylation, nitric oxide, and extracellular K+in the regulation of NKA in skeletal muscle are highlighted. © 2016 the American Physiological Society.

Poljsak B.,University of Ljubljana | Milisav I.,University of Ljubljana
Oxidative Medicine and Cellular Longevity | Year: 2012

Oxidative stress arises when there is a marked imbalance between the production and removal of reactive oxygen species (ROS) in favor of the prooxidant balance, leading to potential oxidative damage. ROSs were considered traditionally to be only a toxic byproduct of aerobic metabolism. However, recently, it has become apparent that ROS might control many different physiological processes such as induction of stress response, pathogen defense, and systemic signaling. Thus, the imbalance of the increased antioxidant potential, the so-called antioxidative stress, should be as dangerous as well. Here, we synthesize increasing evidence on antioxidative stress-induced beneficial versus harmful roles on health, disease, and aging processes. Oxidative stress is not necessarily an un-wanted situation, since its consequences may be beneficial for many physiological reactions in cells. On the other hand, there are potentially harmful effects of antioxidative stress, especially in the cases of overconsumption of synthetic antioxidants. Antioxidants can neutralize ROS and decrease oxidative stress; however, this is not always beneficial in regard to disease formation or progression (of, e.g., cancer) or for delaying aging. © 2012 B. Poljsak and I. Milisav.

Dobovsek I.,University of Ljubljana
Journal of Thermal Stresses | Year: 2016

For a system of field equations of hyperbolic thermoelasticity, we derive a propagation condition for a thermoelastic disturbance in a form of homogeneous plane wave in deformation and temperature. The corresponding dispersion relation is given in an explicit form, together with the dependence of characteristic coefficients on the principal invariants of the tensor of isothermal elasticity, heat conductivity, and thermoelasticity. Discussion of different types of homogeneous thermoelastic plane waves is given as well. Derived methodology is applied in the analysis of Green–Naghdi model. 2016 Copyright © Taylor & Francis Group, LLC

Krajnc N.,University of Ljubljana
Journal of Child Neurology | Year: 2014

Rett syndrome is a neurodevelopmental disorder that manifests itself early in childhood, progresses with the evolution of characteristic clinical signs and symptoms and is confirmed by mutation in the methyl-CpG-binding protein 2 gene. Seizures are present in a majority of Rett patients. Respiratory dysrhythmia in the awake state is present in two-thirds of patients, leading in some cases to severe nonepileptic paroxysmal events. There are no optimal treatment recommendations thus far. The aim of this case study is to present the electro-clinical correlation of severe respiratory dysrhythmia mimicking seizures in 2 Rett patients and effective treatment with topiramate. © The Author(s) 2013.

Kajtna J.,Aerospace d.d. Ipaveva ulica 32 | Krajnc M.,University of Ljubljana
International Journal of Adhesion and Adhesives | Year: 2011

In the following study, a synthesis and characterization of UV crosslinkable acrylic pressure sensitive adhesives are presented. Different amounts of unsaturated photoinitiator 4-acryloyloxy benzophenone (4-ABF) were added in t-butyl acrylate/2-ethylhexyl acrylate monomer mixture and then polymerized using a suspension polymerization technique. The adhesive suspension was coated on a pilot coating machine, dried by application of IR and subsequently crosslinked under UV light. The copolymerized 4-ABF photoinitiator will produce reactive radicals upon absorption of UV light, which are capable of initiating a rapid chain reaction with neighboring CH positions of polymer side chains, what leads to formation of crosslinked polymer structures. UV crosslinking process was monitored by ATR-FTIR spectroscopic technique. Adhesion properties of the synthesized materials were determined using standard measurements of tack, peel and shear strength. Results have shown that all adhesive properties are strongly influenced by the degree of crosslinking of the microspheres, which increased with higher amounts of added 4-ABF photoinitiator. All the three measured adhesive properties showed a substantial decrease even at small amounts of added 4-ABF. The decrease in adhesion may be correlated with higher crosslinking density, what also resulted in higher gel phase amounts. Determination of glass transition temperature showed minor difference between adhesive coatings. © 2010 Elsevier Ltd. All rights reserved.

Kalin M.,University of Ljubljana | Simic R.,University of Ljubljana
Applied Surface Science | Year: 2013

Polar molecules are known to affect the friction and wear of steel contacts via adsorption onto the surface, which represents one of the fundamental boundary-lubrication mechanisms. Since the basic chemical and physical effects of polar molecules on diamond-like carbon (DLC) coatings have been investigated only very rarely, it is important to find out whether such molecules have a similar effect on DLC coatings as they do on steel. In our study the adsorption of hexadecanol in various concentrations (2-20 mmol/l) on DLC was studied under static conditions using an atomic force microscope (AFM). The amount of surface coverage, the size and the density of the adsorbed islands of alcohol molecules were analyzed. Tribological tests were also performed to correlate the wear and friction behaviours with the adsorption of molecules on the surface. In this case, steel surfaces served as a reference. The AFM was successfully used to analyze the adsorption ability of polar molecules onto the DLC surfaces and a good correlation between the AFM results and the tribological behaviour of the DLC and the steel was found. We confirmed that alcohols can adsorb physically and chemically onto the DLC surfaces and are, therefore, potential boundary-lubrication agents for the DLC coatings. The adsorption of alcohol onto the DLC surfaces reduces the wear of the coatings, but it is less effective in reducing the friction because of the already inherently low-friction properties of DLC. Tentative adsorption mechanisms that include the environmental species effect, the temperature effect and the tribological rubbing effect are proposed for DLC and steel surfaces. © 2013 Elsevier B.V.

Antiplatelet drugs represent one of the basic options for management of patients with diff erent atherosclerotic diseases. Aspirin is the oldest and most often prescribed antiplatelet drug. The efficacy of aspirin depends on the clinical characteristics of the treated population and probably also on the type or location of atherosclerotic disease. It seems that it is most effective in coronary patients with clinically unstable disease, less effective in prevention of cerebrovascular incidents, and its efficacy is uncertain in peripheral artery disease (PAD) patients. One of the first meta-analyses (Antithrombotic Trialists' Collaboration - ATC) indicated that antiplatelet drugs also significantly reduce cardiovascular events in patients with PAD. However, only one third of the PAD patients included were treated with aspirin, while the rest received other antiplatelet drugs. The latest ATC meta-analysis of randomized control trials of aspirin therapy involving patients with diabetes and PAD demonstrated no benefit of aspirin in reducing cardiovascular events. Also in patients with preclinical PAD (pathological ankle brachial index) aspirin did not result in a significant reduction of vascular events. The new anti-platelet drugs prasugrel, ticagrelor and picotamide seem to be more effective than aspirin in PAD patients, particularly in diabetic patients with PAD. In conclusion, antiplatelet drugs are effective in prevention of cardiovascular events in different atherosclerotic diseases, including PAD. However, recent studies indicated that in PAD patients aspirin is less effective than in coronary artery disease. New anti-platelet drugs showed marginal superiority over aspirin without definite advantages. Aspirin thus remains the first line of antiplatelet drug for secondary prevention of cardiovascular events in PAD patients and clopidogrel as its effective alternative. Further, new studies on PAD patients are necessary to better define the role of anti-platelet agents in these patients and one of the promising ways of access to antiplatelet treatment would be personalized anti-platelet therapy. © 2013 Hans Huber Publishers, Hogrefe AG, Bern.

Makuc J.M.,University of Ljubljana | Petrovic D.,University of Ljubljana
Cardiovascular and Hematological Agents in Medicinal Chemistry | Year: 2011

A genetic component of diabetes and its complications (including diabetic nephropathy (DN)) is obvious, but the causative genes and mechanisms have not yet been satisfactorily identified. Oxidative stress is a single mechanism relating all major pathways responsible for diabetic damage. Numerous oxidative stress-related genes are positional candidates (determined by GWAS) and candidate genes studies confirm the association of their polymorphisms with DN. We present here their overview and connection to the "new antioxidant" therapy principle. © 2011 Bentham Science Publishers.

Batagelj V.,University of Ljubljana | Cerinsek M.,Hruska d.o.o.
Scientometrics | Year: 2013

In the paper we show that the bibliographic data can be transformed into a collection of compatible networks. Using network multiplication different interesting derived networks can be obtained. In defining them an appropriate normalization should be considered. The proposed approach can be applied also to other collections of compatible networks. The networks obtained from the bibliographic data bases can be large (hundreds of thousands of vertices). Fortunately they are sparse and can be still processed relatively fast. We answer the question when the multiplication of sparse networks preserves sparseness. The proposed approaches are illustrated with analyses of collection of networks on the topic "social network" obtained from the Web of Science. The works with large number of co-authors add large complete subgraphs to standard collaboration network thus bluring the collaboration structure. We show that using an appropriate normalization their effect can be neutralized. Among other, we propose a measure of collaborativness of authors with respect to a given bibliography and show how to compute the network of citations between authors and identify citation communities. © 2013 Akadémiai Kiadó, Budapest, Hungary.

Ocepek U.,University of Ljubljana | Bosnic Z.,University of Ljubljana | Nancovska Serbec I.,University of Ljubljana | Rugelj J.,University of Ljubljana
Computers and Education | Year: 2013

There are many adaptive learning systems that adapt learning materials to student properties, preferences, and activities. This study is focused on designing such a learning system by relating combinations of different learning styles to preferred types of multimedia materials. We explore a decision model aimed at proposing learning material of an appropriate multimedia type. This study includes 272 student participants. The resulting decision model shows that students prefer well-structured learning texts with color discrimination, and that the hemispheric learning style model is the most important criterion in deciding student preferences for different multimedia learning materials. To provide a more accurate and reliable model for recommending different multimedia types more learning style models must be combined. Kolb's classification and the VAK classification allow us to learn if students prefer an active role in the learning process, and what multimedia type they prefer. © 2013 Elsevier Ltd. All rights reserved.

Skrinjar R.,University of Ljubljana | Trkman P.,University of Ljubljana
International Journal of Information Management | Year: 2013

This paper studies the role of business process management in creating a higher business process orientation. The purpose is to analyze previously suggested practices to identify those that are critical at a certain business process orientation maturity level and those that are not. A case study is used to identify the critical success factors. Then a statistical analysis of a sample of 324 companies is undertaken to operationalize the success factors in the form of critical practices. Organizations following these critical practices at a certain level will reach higher process orientation sooner. © 2012 Elsevier Ltd.

Podnar S.,University of Ljubljana
Journal of Neurology | Year: 2015

Phrenic neuropathies (PN) are an important cause of dyspnoea, orthopnoea and hypercapnic respiratory failure. However, there is no agreement on the nosology of this disorder. The aim of this cohort study was to analyze the author’s and published PN patients and compare them with other immune-mediated focal neuropathies to determine the most appropriate nomenclature and classification of the disorder. All patients with PN referred to the author from March 2004 to March 2013 were included. In addition, to identify previously published patients with PN, a PubMed search was done. The demographic and clinical characteristics of both series were then compared with the published series of neuralgic amyotrophy (NA) patients. Of 19 PN patients from the author’s series, 11 % fulfilled the criteria for definite and 58 % for probable NA; while in 58 previous patients, the values were 16 and 48 %, respectively. PN and NA both have a male preponderance and a frequent history of preceding events, but PN occur in an older population and more often in diabetics, are less commonly associated with pain, and have a less complete recovery. Although demonstrating some similarities with NA, the high proportion of isolated (particularly bilateral) PN point to a probable immune-mediated attack against some phrenic nerve-specific antigen with occasional spill-over to neighboring nerves. As a consequence, idiopathic PN seems to be more appropriately regarded as a distinct entity within the spectrum of immune-mediated focal neuropathies rather than as a variant of NA. © 2014, Springer-Verlag Berlin Heidelberg.

Skok G.,University of Ljubljana
Atmospheric Research | Year: 2016

The Fraction Skill Score (FSS) is a recently developed and popular metric used for precipitation verification. A compact analytical expression for FSS is derived for a case with a single displaced rainy grid point in a rectangular domain. The existence of an analytical solution is used to determine some properties of FSS, which might also be applicable in other cases since the rain areas of any shape will asymptote towards this solution if the displacement is sufficiently large. The use of the simple square shape of the neighborhood causes the FSS value to be dependent on the direction of the displacements (not only on the displacement size). The effect is limited in scope but can increase or decrease the FSS value by 0.1. Moving a nearby border closer to the rainy points can either increase or decrease the FSS value, depending on the location of the border. The FSS value near a border can be at most 33% larger than the FSS value in the infinite domain, assuming the same neighborhood size and displacement. The effect of the nearby corner is similar to the effect of the nearby border but is stronger. The useful forecast criteria (FSSuseful) is defined as a value of FSS for a precipitation feature with a displacement half the neighborhood size. FSSuseful for a displaced rainy grid point depends on the orientation of the displacement being the largest for displacements that are parallel to the borders and the smallest for a diagonal displacement for which the value can be as low as 0.42. An analysis of a real dataset was also performed, which showed that the border effect is usually small, but in some cases the effect becomes large (an increase of FSS value up to 70% was identified). The likelihood of a strong border effect in real datasets increases significantly if the neighborhood size at FSS=0.5 is comparable or larger than the domain size. © 2015 Elsevier B.V.

Bonak M.,University of Ljubljana | Matko D.,University of Ljubljana | Blai S.,University of Ljubljana
Robotics and Autonomous Systems | Year: 2012

In recent years, Unmanned Aerial Vehicles (UAVs) have gained increasing popularity. These vehicles are employed in many applications, from military operations to civilian tasks. One of the main fields of UAV research is the vehicle positioning problem. Fully autonomous vehicles are required to be as self-sustained as possible in terms of external sensors. To achieve this in situations where the global positioning system (GPS) does not function, computer vision can be used. This paper presents an implementation of computer vision to hold a quadrotor aircraft in a stable hovering position using a low-cost, consumer-grade, video system. The successful implementation of this system required the development of a data-fusion algorithm that uses both inertial sensors and visual system measurements for the purpose of positioning. The system design is unique in its ability to successfully handle missing and considerably delayed video system data. Finally, a control algorithm was implemented and the whole system was tested experimentally. The results suggest the successful continuation of research in this field. © 2011 Elsevier B.V. All rights reserved.

Poljsak B.,University of Ljubljana | Fink R.,University of Ljubljana
Oxidative Medicine and Cellular Longevity | Year: 2014

Overproduction of reactive oxygen and nitrogen species can result from exposure to environmental pollutants, such as ionising and nonionising radiation, ultraviolet radiation, elevated concentrations of ozone, nitrogen oxides, sulphur dioxide, cigarette smoke, asbestos, particulate matter, pesticides, dioxins and furans, polycyclic aromatic hydrocarbons, and many other compounds present in the environment. It appears that increased oxidative/nitrosative stress is often neglected mechanism by which environmental pollutants affect human health. Oxidation of and oxidative damage to cellular components and biomolecules have been suggested to be involved in the aetiology of several chronic diseases, including cancer, cardiovascular disease, cataracts, age-related macular degeneration, and aging. Several studies have demonstrated that the human body can alleviate oxidative stress using exogenous antioxidants. However, not all dietary antioxidant supplements display protective effects, for example, β -carotene for lung cancer prevention in smokers or tocopherols for photooxidative stress. In this review, we explore the increases in oxidative stress caused by exposure to environmental pollutants and the protective effects of antioxidants. © 2014 Borut Poljšak and Rok Fink.

Cabello S.,University of Ljubljana | Cabello S.,Institute for Mathematics
Algorithmica (New York) | Year: 2012

We show how to compute in O(n 4/3log∈ 1/3 n+n 2/3 k 2/3log∈n) time the distance between k given pairs of vertices of a planar graph G with n vertices. This improves previous results whenever (n/log∈n) 5/6≤k≤n 2/ log∈ 6 n. As an application, we speed up previous algorithms for computing the dilation of geometric planar graphs. © 2010 Springer Science+Business Media, LLC.

The 12 April 1998 M w = 5.6 Krn Mountains earthquake with a maximum intensity of VII-VIII on the EMS-98 scale caused extensive environmental effects in the Julian Alps. The application of intensity scales based mainly on damage to buildings was limited in the epicentral area, because it is a high mountain area and thus very sparsely populated. On the other hand, the effects on the natural environment were prominent and widespread. These facts and the introduction of a new Environmental Seismic Intensity scale (ESI 2007) motivated a research aimed to evaluate the applicability of ESI 2007 to this event. All environmental effects were described, classified and evaluated by a field survey, analysis of aerial images and analysis of macroseismic questionnaires. These effects include rockfalls, landslides, secondary ground cracks and hydrogeological effects. It was realized that only rockfalls (78 were registered) are widespread enough to be used for intensity assessment, together with the total size of affected area, which is around 180 km 2. Rockfalls were classified into five categories according to their volume. The volumes of the two largest rockfalls were quantitatively assessed by comparison of Digital Elevation Models to be 15 × 10 6 m 3 and 3 × 10 6 m 3. Distribution of very large, large and medium size rockfalls has clearly defined an elliptical zone, elongated parallel to the strike of the seismogenic fault, for which the intensity VII-VIII was assessed. This isoseismal line was compared to the tentative EMS-98 isoseism derived from damage-related macroseismic data. The VII-VIII EMS-98 isoseism was defined by four points alone, but a similar elongated shape was obtained. This isoseism is larger than the corresponding ESI 2007 isoseism, but its size is strongly controlled by a single intensity point lying quite far from others, at the location where local amplification is likely. The ESI 2007 scale has proved to be an effective tool for intensity assessment in sparsely populated mountain regions not only for very strong, but for moderate earthquakes as well. This study has shown that the quantitative definition of rockfall size and frequency, which is diagnostic for each intensity, is not very precise in ESI 2007, but this is understandable since the rockfall size is related not only to the level of shaking, but also depends highly on the vulnerability of rocky slopes. © 2012 Author(s). CC Attribution 3.0 License.

Urbic T.,University of Ljubljana | Dill K.A.,University of California at San Francisco
Journal of Chemical Physics | Year: 2010

We develop a statistical mechanical model for the thermal and volumetric properties of waterlike fluids. Each water molecule is a two-dimensional disk with three hydrogen-bonding arms. Each water interacts with neighboring waters through a van der Waals interaction and an orientation-dependent hydrogen-bonding interaction. This model, which is largely analytical, is a variant of the Truskett and Dill (TD) treatment of the "Mercedes-Benz" (MB) model. The present model gives better predictions than TD for hydrogen-bond populations in liquid water by distinguishing strong cooperative hydrogen bonds from weaker ones. We explore properties versus temperature T and pressure p. We find that the volumetric and thermal properties follow the same trends with T as real water and are in good general agreement with Monte Carlo simulations of MB water, including the density anomaly, the minimum in the isothermal compressibility, and the decreased number of hydrogen bonds for increasing temperature. The model reproduces that pressure squeezes out water's heat capacity and leads to a negative thermal expansion coefficient at low temperatures. In terms of water structuring, the variance in hydrogen-bonding angles increases with both T and p, while the variance in water density increases with T but decreases with p. Hydrogen bonding is an energy storage mechanism that leads to water's large heat capacity (for its size) and to the fragility in its cagelike structures, which are easily melted by temperature and pressure to a more van der Waals-like liquid state. © 2010 American Institute of Physics.

Dolinsek J.,Jozef Stefan Institute | Dolinsek J.,University of Ljubljana
Chemical Society Reviews | Year: 2012

Electrical and thermal transport properties of quasicrystals are reviewed on the examples of i-Ag-In-Yb and i-Al-Cu-Fe icosahedral phases and d-Al-Co-Ni decagonal phase. Using samples of single-grain morphology and high structural quality, and performing the measurements along well-defined crystallographic directions, the following basic questions in the context of physical properties of quasicrystals are addressed, both experimentally and theoretically: (1) are the unusual transport properties of quasicrystals introduced by the quasiperiodicity of the structure or are they a consequence of complex local atomic order with no direct relationship to the quasiperiodicity; (2) what is the role of the electronic structure of quasicrystals in their electronic transport properties, especially the pseudogap in the electronic density of states in the vicinity of the Fermi energy; (3) what is the anisotropy of the transport coefficients along different crystallographic directions for icosahedral and decagonal quasicrystals and (4) what are the true intrinsic properties of quasicrystalline phases? © 2012 The Royal Society of Chemistry.

Lorbek G.,University of Ljubljana | Lewinska M.,University of Ljubljana | Rozman D.,University of Ljubljana
FEBS Journal | Year: 2012

The present review describes the transgenic mouse models that have been designed to evaluate the functions of the cytochrome P450s involved in cholesterol and bile acid synthesis, as well as their link with disease. The knockout of cholesterogenic Cyp51 is embrionally lethal, with symptoms of Antley-Bixler syndrome occurring in mice, whereas the evidence for this association is conflicting in humans. Disruption of Cyp7a1 from classic bile acid synthesis in mice leads to either increased postnatal death or a milder phenotype with elevated serum cholesterol. The latter is similar to the case in humans, where CYP7A1 mutations associate with high plasma low-density lipoprotein and hepatic cholesterol content, as well as deficient bile acid excretion. Disruption of Cyp8b1 from an alternative bile acid pathway results in the absence of cholic acid and a reduced absorption of dietary lipids; however, the human CYP8B1 polymorphism fails to explain differences in bile acid composition. Unexpectedly, apparently normal Cyp27a1 -/- mice still synthesize bile acids that originate from the compensatory pathway. In humans, CYP27A1 mutations cause cerebrotendinous xanthomatosis, suggesting that only mice can compensate for the loss of alternative bile acid synthesis. In line with this, Cyp7b1 knockouts are also apparently normal, whereas human CYP7B1 mutations lead to a congenital bile acid synthesis defect in children or spastic paraplegia in adults. Mouse knockouts of the brain-specific Cyp46a1 have reduced brain cholesterol excretion, whereas, in humans, CYP46A1 polymorphisms associate with cognitive impairment. At present, cytochrome P450 family 39 is poorly characterized. Despite important physiological differences between humans and mice, mouse models prove to be an invaluable tool for understanding the multifactorial facets of cholesterol and bile acid-related disorders. © 2012 FEBS.

Mehle N.,Slovenian National Institute of Biology | Trdan S.,University of Ljubljana
Journal of Pest Science | Year: 2012

Many thrips are pests of commercial crops due to the damage they cause by feeding on developing flowers or vegetables. Thrips may also serve as vectors for plant diseases, such as tospoviruses. Their small size and predisposition towards enclosed places makes them difficult to detect by phytosanitary inspection. In this review, several methods available for identifying thrips, including their advantages and disadvantages, are discussed. A combination of different methods gives the most reliable identification. Relatively new morphometric, molecular and biochemical methods for identifying thrips species represent valuable alternatives for situations in which correct identification with classical morphological methods is very difficult, time consuming or virtually impossible. However, traditional morphological methods should not be neglected, especially because adequate identification using morphological keys is usually an indispensable first step in the development and validation of these new modern methods. In addition, modern systems may still require specimen identification to the genus level via morphological keys, or such keys may be recommended to confirm the results of modern identification methods. © 2012 Springer-Verlag.

Cvenkel B.,University of Ljubljana | Sket Kontestabile A.,University of Ljubljana
Graefe's Archive for Clinical and Experimental Ophthalmology | Year: 2011

Background: To measure retinal nerve fibre layer (RNFL) thickness with spectral-domain OCT (SD-OCT) in patients with glaucoma, and to evaluate the correlation between visual field parameters and RNFL thickness. Methods: Two hundred twelve subjects - 55 normal, 37 with preperimetric glaucoma (PPG) and 119 with different stages of primary open angle glaucoma (POAG) were enrolled in this study. Standard automated perimetry was performed in all eyes. RNFL thickness was measured for 6 segments of the 3.4 mm diameter circle and for 8 areas corresponding to the Early Treatment Diabetic Retinopathy Study (ETDRS) grid, both centred on the optic disc. RNFL thickness values were calculated for the inner ring surrounding the optic disc border and the outer ring of the ETDRS grid. The association between visual field parameters and RNFL thickness was evaluated with regression analysis and Pearson correlation coefficients. Results: In the normal group, mean RNFL thickness was 93±9 μm for circle and 91±14 μm for inner ring, for the POAG group the values were 58±21 μm for circle and 40±21 μm for inner ring, and for the PPG group the values were 77±15 μm and 59±15 μm, respectively. The differences in RNFL thickness between normal and glaucoma eyes were significant (p<0.001) for all measurements. Mean RNFL thickness between normal and PPG eyes was significantly different for all regions except for the superior-temporal and temporal sector of the circle and for area 7 of the ETDRS grid. In POAG eyes only, RNFL thickness and both mean sensitivity (r=0.558) and mean defect (r=-0.549) correlated significantly. The best parameters for differentiating normal from PPG eyes were inner ring surrounding the optic disc border (area under receiver operator characteristic curves (AUROC)=0.940) and area 4 values (AUROC=0.903) of the ETDRS grid. Conclusions: SD-OCT showed significantly decreased mean RNFL thickness of the inner ring surrounding the optic disc border of the ETDRS grid by 35% in PPG eyes and by 46% in eyes with early glaucoma compared to the control group. These results support the usefulness of this technology. © 2010 Springer-Verlag.

Sediments can pose a threat to humans not only when these deposits are polluted but also due to their large quantities. This physical aspect of sediments as a risk will be shown on a case study of a sediment-related disaster that occurred in the mountainous part of Slovenia, Central Europe in 2000. In November 2000, after a long wet period a large debris landslide had been triggered on the Stože slope and stopped in the channel of the Mangart creek. Such an event took the majority of local inhabitants and emergency staff by surprise. Nevertheless, they had just organized the first mitigation measures when, after 35 hours, they were surprised by an even larger debrisflowinitiated as the second phase of the same mass movement event. Within a few minutes, the wet debris flow had devastated the alpine valley of the Koritnica River and killed 7 people in the village of Log pod Mangartom. This paper deals with crisis management and first mitigation measures under this very tense situation of searching for dead bodies. The uncertainty about possible new debris flows drove all inhabitants out of the village by a decision of the civil protection unit, and also other activities of the emergency relief units were overshadowed by the 7 victims. One of the main problems and challenges at the same time was the over 700,000m3 of wet debris flow deposits in the area of the village of Log pod Mangartom within the Triglav National park, which posed a direct threat of flooding during the first heavy rainfalls in spring 2001, and which were about to be removed to make place for future debris flows. The understanding about what really happened or about the immediate triggering factors was different among the professionals in charge for relief action and for preparing a final remediation plan. The first phase during and immediately after the disaster (relief intervention of emergency units especially those for civil protection) can be described as Concern-Driven Crisis Management or as Judgment-Based Crisis Management, respectively. The Quantitative Risk Assessment came into play in the second remediation phase through special law enforcement. Even after 10 years since the disaster, general public perception speaks in favor of judgment-based risk management rather than quantitative risk assessment, a situation that can be explained by the poor understanding of the system by local inhabitants, by low public involvement in the preparation of the final remediation plan undertaken by the state agencies, and by the fact that the final remediation is still not finished. © 2010 SETAC.

Omejec G.,University of Ljubljana | Zgur T.,University of Ljubljana | Podnar S.,University of Ljubljana
Clinical Neurophysiology | Year: 2015

Objective: To report diagnostic accuracy of ultrasonography (US) and compare it to standard 10-cm nerve conduction studies (NCSs), and short-segment NCSs (SSNCSs) across the elbow in the diagnosis of ulnar neuropathy at the elbow (UNE). Methods: In a broad spectrum of consecutive patients with suspected UNE a prospective and blinded study was performed. This included a clinical examination, electrodiagnostic (EDx) and US studies. In clinically definite UNE patients we compared the sensitivity of SSNCSs, of 10-cm NCSs across the elbow, and of US. The specificity was calculated in asymptomatic controls. Results: We studied 113 affected arms in 109 patients; definite UNE was diagnosed in 81, and alternative conditions in 12 arms. The sensitivity of SSNCSs was 89%, of 10-cm NCSs 83%, and of US 71%. We found the highest sensitivity of US in patients with axonal UNE (93%), followed by conduction slowing (82%) and conduction block (55%). Specificity of SSNCSs was 80%, of 10-cm NCSs 82%, and of US 82%. Conclusion: The present study found the highest diagnostic accuracy of SSNCSs (85%), followed by 10-cm NCSs (83%), and of US (77%). Significance: US is particularly useful in patients with axonal UNE, while SSNCSs in UNE with conduction block. © 2014 International Federation of Clinical Neurophysiology.

Yarmush M.L.,Massachusetts General Hospital | Yarmush M.L.,Rutgers University | Golberg A.,Massachusetts General Hospital | Sersa G.,Institute of Oncology Ljubljana | And 2 more authors.
Annual Review of Biomedical Engineering | Year: 2014

When high-amplitude, short-duration pulsed electric fields are applied to cells and tissues, the permeability of the cell membranes and tissue is increased. This increase in permeability is currently explained by the temporary appearance of aqueous pores within the cell membrane, a phenomenon termed electroporation. During the past four decades, advances in fundamental and experimental electroporation research have allowed for the translation of electroporation-based technologies to the clinic. In this review, we describe the theory and current applications of electroporation in medicine and then discuss current challenges in electroporation research and barriers to a more extensive spread of these clinical applications. Copyright © 2014 by Annual Reviews. All rights reserved.

Golobic I.,University of Ljubljana | Petkovsek J.,University of Ljubljana | Kenning D.B.R.,Brunel University
International Journal of Heat and Mass Transfer | Year: 2012

Growth of an isolated bubble and horizontal coalescence events between bubbles of dissimilar size were examined during pool nucleate boiling of water on a horizontal, electrically-heated titanium foil 25 μm thick. Wall temperature measurements on the back of the foil by high-speed IR camera, synchronized with high-speed video camera recordings of the bubble motion, improved the temporal and spatial resolution of previous observations by high-speed liquid crystal thermography to 1 ms and 40 μm, respectively, leading to better detailed maps of the transient distributions of wall heat flux. The observations revealed complex behaviour that disagreed with some other observations and current modelling assumptions for the mechanisms of heat transfer over the wall contact areas of bubbles and interactions between bubbles. Heat transfer occurred from the entire contact area and was not confined to a narrow peripheral triple-contact zone. There was evidence of an asymmetrical interaction between bubbles before coalescence. It was hypothesised that a fast-growing bubble pushed superheated liquid under a slow-growing bubble. Contact of this liquid with regions of the wall that had been pre-cooled during bubble growth caused local reductions in the wall heat flux. During coalescence, movement of liquid under both bubbles caused further changes in the wall heat flux that also depended on pre-cooling. Contraction of the contact area caused a peripheral reduction in the heat flux and there was no evidence of a large increase in heat flux during detachment. Boiling on very thin foils imposes special conditions. Sensitivity to the thermal history of the wall must be taken into account when applying the observations and hypotheses to other conditions. © 2011 Elsevier Ltd. All rights reserved.

Mavri A.,University of Ljubljana | Smole Mozina S.,University of Ljubljana
International Journal of Food Microbiology | Year: 2013

The potential for adaptive resistance of Campylobacter jejuni and Campylobacter coli after step-wise exposure to increasing sub-inhibitory concentrations of five biocides as triclosan, benzalkonium chloride, cetylpyridinium chloride, chlorhexidine diacetate and trisodium phosphate, was investigated, to identify the mechanisms underlying resistance. The biocide resistance and cross-resistance to the antimicrobials erythromycin and ciprofloxacin, and to sodium dodecyl sulphate, were examined according to the broth microdilution method. The presence of active efflux was studied on the basis of restored sensitivity in the presence of the efflux pump inhibitors phenylalanine-arginine beta-naphthylamide, 1-(1-naphthylmethyl)-piperazine, cyanide 3-chlorophenylhydrazone, verapamil and reserpine. Changes in the outer membrane protein profiles and morphological changes in adapted strains were studied, as compared with the parent strains. Repeated exposure of C. jejuni and C. coli to biocides resulted in partial increases in tolerance to biocides itself, to other biocides and antimicrobial compounds. The developed resistance was stable for up to 10 passages in biocide-free medium. More than one type of active efflux was identified in adapted strains. These adapted strains showed different alterations to their outer membrane protein profiles, along with morphological changes. The data presented here suggest that different mechanisms are involved in adaptation to biocides and that this adaptation is unique to each strain of Campylobacter and does not result from a single species-specific mechanism. © 2012 Elsevier B.V.

Ravnihar K.,Orthopedic Hospital Valdoltra | Barlic A.,Educell Ltd | Drobnic M.,University of Ljubljana
Arthroscopy - Journal of Arthroscopic and Related Surgery | Year: 2014

Purpose To evaluate the hypothetical toxic effect of local anesthetics on the articular cartilage using patient data from autologous chondrocyte cultivation with different anesthesia types used for arthroscopic cartilage biopsy specimen procurement. Methods A retrospective analysis of patient data from the national autologous chondrocyte implantation registry and the corresponding hospital records was approved by the National Medical Ethics Committee. Articular cartilage biopsy specimens from the knees of 49 consecutive patients assigned for autologous chondrocyte implantation (aged 14 to 44 years) were procured from the non-weight-bearing articular surface during arthroscopy under general anesthesia (12 patients), spinal anesthesia (18 patients), or local anesthesia (intra-articular injection of 15 to 20 mL of 2% lidocaine hydrochloride) (19 patients). All the biopsy specimens were further manipulated following the same chondrocyte cultivation protocol. General patient data and surgery-related parameters, together with chondrocyte viability, population doublings, and chondrocyte morphology in biopsy specimens and primary cell cultures, were analyzed and compared across different types of anesthesia. Results Patients in the general, spinal, and local anesthesia groups showed no statistical differences in age (27 years, 29 years, and 32 years, respectively), duration of surgery (36 minutes, 37 minutes, and 39 minutes, respectively), weight of biopsy specimens (110 mg, 178 mg, and 130 mg, respectively), cell viability in cartilage biopsy specimens (67%, 69%, and 78%, respectively) or primary cultures (95%, 95%, and 95%, respectively), and population doublings (5.2, 5.2, and 5.2, respectively). Similar chondrocyte morphology in primary cell cultures was observed among the 3 groups. Conclusions This retrospective study showed that a single intra-articular injection of lidocaine hydrochloride used for knee arthroscopy did not influence the viability, morphology, and cultivation potential of chondrocytes in articular cartilage biopsy specimens assigned for autologous chondrocyte implantation. Level of Evidence Level IV, retrospective comparative study. © 2014 by the Arthroscopy Association of North America.

Background: Vitamin K antagonists, such as warfarin, are standard treatments for stroke prophylaxis in patients with atrial fibrillation. Patient outcomes depend on quality of warfarin management, which includes regular monitoring and dose adjustments. Recently, novel oral anticoagulants (NOACs) that do not require regular monitoring offer an alternative to warfarin. The aim of this study was to evaluate whether cost effectiveness of NOACs for stroke prevention in atrial fibrillation depends on the quality of warfarin control. Methods: We developed a Markov decision model to simulate warfarin treatment outcomes in relation to the quality of anticoagulation control, expressed as percentage of time in the therapeutic range (TTR). Standard treatment with adjusted-dose warfarin and improved anticoagulation control by genotype-guided dosing were compared with dabigatran, rivaroxaban, apixaban and edoxaban. The analysis was performed from the Slovenian healthcare payer perspective using 2014 costs. Results: In the base case, the incremental cost-effectiveness ratio for apixaban, dabigatran and edoxaban was below the threshold of €25,000 per quality-adjusted life-years compared with adjusted-dose warfarin with a TTR of 60 %. The probability that warfarin was a cost-effective option was around 1 %. This percentage rises as the quality of anticoagulation control improves. At a TTR of 70 %, warfarin was the preferred treatment in half the iterations. Conclusion: The cost effectiveness of NOACs for stroke prevention in patients with nonvalvular atrial fibrillation who are at increased risk for stroke is highly sensitive to warfarin anticoagulation control. NOACs are more likely to be cost-effective options in settings with poor warfarin management than in settings with better anticoagulation control, where they may not represent good value for money. © 2014, Springer International Publishing Switzerland.

Trcek D.,University of Ljubljana | Brodnik A.,University of Ljubljana
IEEE Wireless Communications | Year: 2013

We are witnessing increasing penetration of pervasive computing into business and personal environments. Its advances, among other things, enable new opportunities for better health services but, as a side effect, it introduces new threats to privacy. If anywhere, it is in the health care sector that privacy is of utmost importance. Knowing further that internet of things devices typically lack computing and energy resources, the need for providing appropriate privacy is a hard issue. This paper therefore addresses privacy for internet of things technologies by focusing on the most ¿ primitive¿ members, bare sensors and RFIDs. Based on lessons learned in this domain, a strategy of incrementally adjusting existing protocols is adopted for deployment in the area of wireless medical sensors body area networks. By doing so, new contributions that are quantifiably lightweight and that enable privacy, together with confidential exchange of captured measured quantities, are provided. In addition to such hard security solutions, the paper addresses trust management methods as a complementary, soft mean for security provisioning. This latter contribution also paves the way for further development and for applications of pervasive computing in general. © 2013 IEEE.

Cadez S.,University of Ljubljana
Expert Systems with Applications | Year: 2013

Contemporary academic environment can be characterized by an overwhelming trend toward enhancing research productivity and knowledge creation. The purpose of this study is to examine the impact of radical social change and subsequent institutional pressures on internationally relevant knowledge creation. The setting examined is business and economics science in Eastern Europe. Using a case study of Slovenian business schools and deploying a bibliometric analysis we find that research productivity is increasing significantly. We note however dilemmas pertaining to the content and quality of knowledge created. Further, we find that international research cooperation has positive quality effects. From a theoretical perspective, we argue that radical social change was not mirrored by such change in normative institutions, whereas recent changes in regulatory institutions seem to have a substantial positive effect on research performance. © 2013 Elsevier Ltd. All rights reserved.

Gjorgiev B.,Jozef Stefan Institute | Cepin M.,University of Ljubljana
Engineering Applications of Artificial Intelligence | Year: 2013

The combined economic-environmental dispatch issue is multidimensional, non-linear, non-convex and highly constrained problem. It involves multiple and often conflicting optimization criteria for which no unique optimal solution can be determined with respect to all criteria. In this paper a multi-objective optimization based solution to the combined economic-environmental power dispatch is proposed. The derivation of the optimal solution is based on the weighted sum method for which improvements are made in direction of penalty function integration. For that purpose a modified dynamic normalization is suggested. A penalization method based on membership functions is introduced in order to calculate the constraint violations. The objective of the proposed method is gaining an optimal solution for the dynamic combined economic-environmental dispatch problem associated to real power systems. Therefore, the algorithm is applied on different test power systems. The obtained results are analyzed and compared with various optimization techniques presented in the literature. The results demonstrate the efficiency of the proposed method in finding solutions toward global optimum. © 2012 Elsevier Ltd. All rights reserved.

Trajkovski M.,Slovenian National Institute of Chemistry | Webba Da Silva M.,University of Ulster | Plavec J.,Slovenian National Institute of Chemistry | Plavec J.,University of Ljubljana
Journal of the American Chemical Society | Year: 2012

A multidimensional heteronuclear NMR study has demonstrated that a guanine-rich DNA oligonucleotide originating from the N-myc gene folds into G-quadruplex structures in the presence of K +, NH 4 +, and Na + ions. A monomeric G-quadruplex formed in K + ion containing solution exhibits three G-quartets and flexible propeller-type loops. The 3D structure with three single nucleotide loops represents a missing element in structures of parallel G-quadruplexes. The structural features together with the high temperature stability are suggestive of the specific biological role of G-quadruplex formation within the intron of the N-myc gene. An increase in K + ion and oligonucleotide concentrations resulted in transformation of the monomeric G-quadruplex into a dimeric form. The dimeric G-quadruplex exhibits six stacked G-quartets, parallel strand orientations, and propeller-type loops. A link between the third and the fourth G-quartets consists of two adenine residues that are flipped out to facilitate consecutive stacking of six G-quartets. © 2012 American Chemical Society.

Galer P.,University of Ljubljana | Korosec R.C.,University of Ljubljana | Vidmar M.,University of Ljubljana | Sket B.,University of Ljubljana
Journal of the American Chemical Society | Year: 2014

It is known that electron donating groups have quite a different effect on the π-delocalization of a conjugate system when bonded at ortho and para as compared to meta positions in the phenyl ring. In the present work, the BF 2 complex of 1-phenyl-3-(3,5-dimethoxyphenyl)-propane-1,3-dione (1), a molecule with two methoxy groups in one of the phenyl rings at meta positions, was prepared. Compound 1 exists as two polymorphs having different mutual orientations of the two methoxy groups: in polymorph A away from each other (termed anti), while in polymorph B one methoxy group is oriented toward the other (syn-anti). In both crystals, the molecules which are antiparallel (the subPh rings as well as dioxaborine are on opposite sides) form stacks through face-to-face π-π interactions, while in polymorph A the crystal packing is further stabilized by intermolecular C(phenyl)-H···F and C(methoxy)-H···F hydrogen bonds. Solid A possesses numerous chromic effects, including mechano-, thermo-, and chronochromism, though the latter to a lesser extent, as well as the effect of rearrangement of the amorphous phase into a more stable crystalline phase A, associated with crystallization-induced emission enhancement (CIEE). The solid-state emission can be repeatedly switched regarding its color and efficiency with excellent reversibility by external stimuli. On the other hand, crystalline solid B undergoes thermal interconversion of syn-anti to the anti conformer. Compound 1 shows a solvatochromic effect (SE), is aggregation-induced emission (AIE) active, and through the sublimation process displays self-assembling crystalline platelike microstructures or microfibers that reveal an obvious optical waveguide effect. © 2014 American Chemical Society.

Boncina M.,University of Ljubljana | Lah J.,University of Ljubljana | Prislan I.,University of Ljubljana | Vesnaver G.,University of Ljubljana
Journal of the American Chemical Society | Year: 2012

Recent theoretical studies performed on the folding/unfolding mechanism of the model telomeric human DNA, 5′-AGGGTTAGGGTTAGGGTTAGGG-3′ (Tel22), have indicated that in the presence of K + ions Tel22 folds into two hybrid G-quadruplex structures characterized by one double and two reversal TTA loops arranged in a different way. They predicted a new unfolding pathway from the initial mixture of hybrid G-quadruplexes via the corresponding intermediate triplex structures into the final, fully unfolded state. Significantly, no experimental evidence supporting the suggested pathway has been reported. In the current work, we performed a comprehensive global thermodynamic analysis of calorimetric (DSC, ITC) and spectroscopic (CD) data obtained on monitoring the folding/unfolding of Tel22 induced by changes of temperature and K + concentration. We show that unfolding of Tel22 may be described as a monomolecular equilibrium three-state process that involves thermodynamically distinguishable folded (F), intermediate (I), and unfolded (U) state. Considering that calorimetric methods cannot distinguish between energetically similar G-quadruplex or triplex conformations predicted by the theoretical model one can conclude that our results represent the first experimental support of the suggested unfolding/folding mechanism of Tel22. This conclusion is confirmed by the fact that the estimated number of K + ions released upon each unfolding step in our thermodynamic model agrees well with the corresponding values predicted by the theoretical model and that the observed changes in enthalpy, entropy, and heat capacity accompanying the F → I and I → U transitions can be reasonably explained only if the intermediate state I is considered to be a triplex structural conformation. © 2012 American Chemical Society.

Martinez A.,University of Colorado at Boulder | Ravnik M.,University of Ljubljana | Lucero B.,University of Colorado at Boulder | Visvanathan R.,University of Colorado at Boulder | And 4 more authors.
Nature Materials | Year: 2014

Colloidal dispersions in liquid crystals can serve as asoft-matter toolkit for the self-assembly of composite materials with pre-engineered properties and structures that are highly dependent on particle-induced topological defects. Here, we demonstrate that bulk and surface defects in nematic fluids can be patterned by tuning the topology of colloidal particles dispersed in them. In particular, by taking advantage of two-photon photopolymerization techniques to make knot-shaped microparticles, we show that the interplay of the topologies of the knotted particles, the nematic field and the induced defects leads to knotted, linked and other topologically non-trivial field configurations. These structures match theoretical predictions made on the basis of the minimization of the elastic free energy and satisfy topological constraints. Our approach may find uses in self-assembled topological superstructures of knotted particles linked by nematic fields, in topological scaffolds supporting the decoration of defect networks with nanoparticles, and in modelling other physical systems exhibiting topologically analogous phenomena. © 2014 Macmillan Publishers Limited.

Pociecha M.,University of Ljubljana | Lestan D.,University of Ljubljana
Chemosphere | Year: 2012

Soil washing with EDTA is known to be an effective means of removing toxic metals from contaminated soil. A practical way of recycling of used soil washing solution remains, however, an unsolved technical problem. We demonstrate here, in a laboratory scale experiment, the feasibility of using acid precipitation to recover up to 50% of EDTA from used soil washing solution obtained after extraction of Pb (5330mgkg -1), Zn (3400mgkg -1), Cd (35mgkg -1) and As (279mgkg -1) contaminated soil. Up to 100% of EDTA residual in the washing solution and 100%, 97%, 98% and 100% of initial Pb, Zn, Cd and As concentration in the solution, respectively, were removed in an electrolytic cell using a graphite anode. We employed the recovered EDTA and treated washing solution to prepare recycled soil washing solution with the same potential for extracting toxic metals from soil as the original. The efficiency of soil washing depends on the EDTA concentration. Using twice recycled 30mmol EDTA kg -1 soil, we removed 44%, 20%, 53% and 61% of Pb, Zn, Cd and As, respectively, from contaminated soil. © 2011 Elsevier Ltd.

Dovrtel K.,University of Ljubljana | Medved S.,University of Ljubljana
Energy and Buildings | Year: 2012

The renewed Energy Performance of Building Directive and European regulations for buildings energy efficiency are becoming increasingly restrictive and moving towards near zero energy buildings. To achieve this goal, amongst others measures, a building utility system has to be carefully designed and optimized to perform efficiently and to utilize renewable energy source to greater extent. This paper is focused on the multi-objective performance optimization of buildings free cooling systems. The optimization was twofold: firstly, the energy consumption and available free cooling potential were estimated using weather forecasts, and secondly, the free cooling system operation regime was optimized to meet the required energy consumption using variable air distribution and flow control. The results of the optimization show the significant influence of such system operation control on system performance indicators. © 2012 Elsevier B.V. All rights reserved.

Budja M.,University of Ljubljana | Mlekuz D.,University of Ljubljana
Holocene | Year: 2010

The Ljubljana Marshes (Ljubljana Moor) is a large wetland in the southern part of the Ljubljana basin in the central part of Slovenia, with well-preserved archaeological evidence of settlements. The data have traditionally been interpreted as the remnants of the prehistoric pile dwelling settlements located in a shallow lake. In this paper, we present new data that challenge these interpretations. An aerial LiDAR survey of the Ižica floodplain on the Ljubljana Marshes has revealed a complex topography of stratified palaeochannels. The 14C dates of the channel infills suggest that the first phase of the palaeochannels can be dated to before 3770 cal. BC, which is contemporary with Eneolithic settlements located on its banks. We suggest that settlements were located in the floodplain, next to active rivers, and not in the lake as was traditionally hypothesised. © The Author(s) 2010.

Rusjan S.,University of Ljubljana | Mikos M.,University of Ljubljana
Biogeochemistry | Year: 2010

Seasonal and diurnal variations of in-stream NO3-N concentration oscillations were studied through high-frequency measurements of streamwater's physical, chemical parameters (in-stream NO3-N concentration, water temperature, dissolved oxygen, pH) and hydrometeorological variables (stream discharge, solar radiation) under hydrologically stable conditions. The study was carried out in 2006, within the 42 km2 forested Padež stream watershed in the southwestern part of Slovenia, which is characterized by distinctive hydrogeological settings (flysch) and climate conditions (transitional area between the Mediterranean and continental climate). Fine temporal data resolution (15-min interval) enabled identification of the factors responsible for seasonal variability in the diurnal pattern of the streamwater NO3-N concentrations versus seasonal and diurnal behavior of meteorological and other water chemistry constituents. The observed seasonal variability of in-stream NO3-N daily oscillations indicates the important role of primary production uptake, particularly during seasons when deciduous vegetation is dormant and light levels in the stream are high. Highest daily NO3-N concentration amplitudes (0.3 mg/l-N) and daily changes in the NO3-N flux (0.4-0.5 g/s-N) were observed in spring; the NO3-N concentration oscillations in summer showed a considerably smaller effect of the in-stream uptake (maximum NO3-N daily concentration amplitude 0.1 mg/l-N; daily change in the NO3-N flux 0.02 g/s-N). Seasonal shifts in the timing of daily maximum (up to 6 h) and minimum NO3-N concentrations (between 1 and 3 h) provided some additional indications of seasonal changes in the in-stream primary production uptake and its relation to the terrestrial component of the forested watershed. © Springer Science+Business Media B.V. 2009.

Blaganje M.,University of Ljubljana | Lukanovic A.,University of Ljubljana
International Urogynecology Journal and Pelvic Floor Dysfunction | Year: 2013

Introduction and hypothesis: Limitations of the existing treatment methods for stress urinary incontinence (SUI) have encouraged investigation of new therapeutic approaches in the field of regenerative medicine. Enabled by tissue engineering technology safety, feasibility and efficacy of ultrasound-guided intrasphincteric autologous myoblast implantation to treat SUI presented in the accompanying video were assessed in a pilot study of 38 women. Methods: Following upper arm muscle biopsy, autologous myoblast suspension was injected into the extrinsic urethral sphincter under transurethral ultrasound visualization. Functional electrical stimulation (FES) was used postoperatively to possibly enhance cell integration. Objective and subjective parameters were compared at 6 weeks, 3 months, and 6 months postoperatively. Results: The tissue harvest, laboratory tissue processing, and myoblast implantation were successful in all 38 patients. No serious adverse events were reported through the course of the study. Objective and subjective measurements collected at baseline were significantly improved at 6 weeks postoperatively. Additional improvement or a plateau was observed at 3 and 6 months postoperatively, not being negatively influenced by discontinuation of FES. Of the patients, 23.7 % considered their SUI cured, and 52.6 % reported improvement at 6 months; 95 % would recommend this treatment to others. Conclusions: Intrasphincteric ultrasound-guided autologous myoblast injection for SUI is feasible. This simple to perform and well-tolerated minimally invasive procedure safely produced promising initial results. © 2012 The International Urogynecological Association.

Kreslin M.,University of Ljubljana | Fajfar P.,University of Ljubljana
Bulletin of Earthquake Engineering | Year: 2010

The seismic evaluation of existing buildings is a more difficult task than the seismic design of new buildings. Non-linear methods are needed if realistic results are to be obtained. However, the application to real complex structures of various evaluation procedures, which have usually been tested on highly idealized structural models, is by no means straightforward. In the paper, a practice-oriented procedure for the seismic evaluation of building structures, based on the N2 method, is presented, together with the application of this method to an existing multi-storey reinforced concrete building. This building, which is asymmetric in plan and irregular in elevation, consists of structural walls and frames. It was designed in 1962 for gravity loads and a minimum horizontal loading (2% of the total weight). The main results presented in terms of the global and local seismic demands are compared with the results of non-linear dynamic response-history analyses. As expected, the structure would fail if subjected to the design seismic action according to Eurocode 8. The shear capacity of the structural walls is the most critical. If the shear capacity of these elements was adequate, the structure would be able to survive the design ground motion according to Eurocode 8, in spite of the very low level of design horizontal forces. The applied approach proved to be a feasible tool for the seismic evaluation of complex structures. However, due to the large randomness and uncertainty which are involved in the determination of both the seismic demand and the seismic capacity, only rough estimates of the seismic behaviour of such structures can be obtained. © 2009 Springer Science+Business Media B.V.

Solvent extraction remains one of the fundamental sample preparation techniques in the analysis of environmental solid samples, but organic solvents are toxic and environmentally harmful, therefore one of the possible greening directions is its miniaturization. The present review covers the relevant research from the field of application of microextraction to the sample preparation of environmental solid samples (soil, sediments, sewage sludge, dust etc.) published in the last decade. Several innovative liquid-phase microextraction (LPME) techniques that have emerged recently have also been applied as an aid in sample preparation of these samples: single-drop microextraction (SDME), hollow fiber-liquid phase microextraction (HF-LPME), dispersive liquid-liquid microextraction (DLLME). Besides the common organic solvents, surfactants and ionic liquids are also used. However, these techniques have to be combined with another technique to release the analytes from the solid sample into an aqueous solution. In the present review, the published methods were categorized into three groups: LPME in combination with a conventional solvent extraction; LPME in combination with an environmentally friendly extraction; LPME without previous extraction. The applicability of these approaches to the sample preparation for the determination of pollutants in solid environmental samples is discussed, with emphasis on their strengths, weak points and environmental impact. © 2014 by the authors.

Miklavcic D.,University of Ljubljana
Journal of Membrane Biology | Year: 2012

Exposure of biological cells to a sufficiently strong external electric field results in increased permeability of cell membranes, referred to as "electroporation." Since all types of cells (animal, plant and microorganism) can be effectively electroporated, electroporation is considered to be a universal method and a platform technology. Electroporation has become a widely used technology applicable to, e.g., cancer treatment, gene transfection, food and biomass processing and microbial inactivation. However, despite significant progress in electroporation-based applications, there is a lack of coordination and interdisciplinary exchange of knowledge between researchers from different scientific domains. Thus, critical mass for new major breakthroughs is missing. This is why we decided to establish cooperation between research groups working in different fields of electroporation. Cooperation in Science and Technology (COST), which funds networking and capacity-building activities, presents a perfect framework for such scientific cooperation. This COST action aims at (1) providing necessary steps toward EU cooperation of science and technology to foster basic understanding of electroporation; (2) improving communication between research groups, resulting in streamlining European research and development activities; and (3) enabling development of new and further development of existing electroporation-based applications by integrating multidisciplinary research teams, as well as providing comprehensive training for early-stage researchers. Results of this COST action will provide multiple societal, scientific and technological benefits from improving existing electroporation-based applications to adding new ones in the fields of medicine, biotechnology and environmental preservation. © The Author(s) 2012.

Classical and nonclassical risk factors contribute to the development of myocardial infarction (MI) in young patients. The aim of the present study was to find out whether insulin resistance and impaired fibrinolysis, with increased plasminogen activator inhibitor (PAI-1), are present in young male post-MI patients, and their relation to additional markers of cardiovascular risk such as endothelial dysfunction (ED) and intima-media thickness (IMT). Forty-one male patients (on average 44 years old) in the stable phase after MI were recruited, with 25 healthy males who did not differ from patients regarding age as controls. Body mass index (BMI) and waist-to-hip ratio were measured and insulin resistance was calculated. Several coagulation/fibrinolytic parameters and inflammation markers were measured. ED was estimated by ultrasound measurement of the flow-mediated dilatation (FMD) of the brachial artery, and IMT was measured on the common carotid artery. BMI was increased in post-MI patients in comparison with healthy controls. Compared with the control group, in post-MI patients PAI-1 antigen (13.8 ± 10.6 vs 9.1 ± 7.6 ng/ml, P = 0.042), PAI-1 activity (14.8 ± 10.8 vs 9.0 ± 8.0 IU/ml, P = 0.015), and fibrinogen were significantly elevated. In patients increased PAI-1, antigen and activity were both significantly positively related to insulin resistance. We found an important negative relation between PAI-1 antigen and FMD (r = -0.32, P = 0.04) and between PAI-1 activity and FMD (r = -0.39, P = 0.01). Our results suggest that PAI-1 can be a link between obesity, insulin resistance, and MI in young patients. It is thus concluded that impaired fibrinolysis with increased PAI-1 may be an important nonclassical risk factor for MI, particularly in young males with increased BMI and insulin resistance. © 2012 Springer.

Mencinger J.,University of Ljubljana | Zun I.,University of Ljubljana
Journal of Computational Physics | Year: 2011

This paper presents a new variant of the volume-of-fluid (VOF) color function C advection algorithm based on the piecewise linear interface construction (PLIC) method suitable for use on general moving grids. From several existing methods for reconstructing the linear interface we adopted the least squares volume-of-fluid interface reconstruction algorithm (LVIRA) which can be easily implemented on general grids. The distinguishing step in the advection algorithm that takes into account the grid movement is the construction of the donating region containing the fluid passing through corresponding cell-faces in a single time-step. The donating regions are constructed utilizing fluid velocity in cell corners relative to grid (corner) velocities. The method is conservative as it complies with the space conservation law (SCL) and requires a proper definition of the grid velocities and fluxes due to the grid movement. The accuracy of the presented advection algorithm is assessed with standard test cases. It is comparable with other PLIC based algorithms on fixed grids, while the applicability on adaptive moving grids enables a considerable reduction in the number of grid cells. © 2010 Elsevier Inc.

Background: The International Classification of Functioning, Disability and Health (ICF) covers all aspects and levels of human functioning. Objectives: The aim of the study was to find out whether the ICF can be used in everyday prosthetics and orthotics (P&O) clinical practice for description of human functioning, and whether it can demonstrate the influence of a prosthesis or an orthosis on a person's functioning. Study Design: Prospective clinical study. Methods: A short list of ICF codes was compiled from Annex 9 and used for one month for all patients seen at the author's P&O outpatient clinics. Results: One hundred patients (59 men, average age 58 years) with different medical problems were included in the study. From 6 to 27 (14 on average) ICF categories from all four components of ICF were used in these patients. The most frequently used category for body functions was mobility of joint functions, for body structures it was structure of the skin and for activities and participation it was walking. Public and private buildings were the only barriers identified. Conclusions: It can be concluded that the ICF can be used in everyday P&O clinical practice. An ICF list of categories provides quick additional information. To be able to demonstrate the influence of P&O devices on person's functioning, at least for activities and participation, one has to use qualifiers. Clinical relevance For clinicians it is important to know that it is possible to use the ICF in clinical practice and that it can demonstrate the impact of P&O devices on a person's functioning. © The International Society for Prosthetics and Orthotics 2011.

On account of the current different requirements in the field of finishing/polishing, e.g., reducing the finishing time, process control, ensuring a clean process, and energy efficiency, hand polishing needs to be replaced with a superior process. One alternative is abrasive flow machining (AFM). In comparison with hand polishing, AFM is an efficient process, suitable for finishing external as well as internal surfaces, which are often complex and out of reach. Due to the drawbacks of AFM, in this work a novel method of abrasive flow machining with a movable mandrel (AFMmm) is proposed and introduced through a case study from the automotive industry. As in the manufacturing sector electric power consumption is the main driver that influences CO2 emissions, a comparative analysis of the energy efficiency of AFM vs. AFMmm is performed. The results of this work show that the application of the novel AFMmm method is capable of removing WEDM-damaged (wire electric discharge machining) surface and produces a polished surface under dry conditions, leaving the machined surface clean. Moreover, the novel upgrade of the AFM process can be significantly more energy efficient and with finishing is simultaneously able to control the micro-topography of the product. The gearing injection mold tool case study shows that the benefits are not related merely to the process, but also to the product. It offers a significant improvement in gear performance, energy efficiency in operation, as well as in fatigue life, which is extended by more than a factor of two. As a contribution, a novel clean and energy efficient AFMmm is presented, capable of synergistically shaping and polishing the geometry of the final product on a micro level and under dry conditions. © 2014 Elsevier Ltd. All rights reserved.

Brecl K.,University of Ljubljana | Topic M.,University of Ljubljana
Renewable Energy | Year: 2011

The energy yield of a photovoltaic (PV) system with fixed free-standing PV arrays is affected also by the self-shading effects. The rows of PV modules in arrays may partially shade the PV modules in the rows behind. In this paper the effects of the row distance on the PV system's energy yield are evaluated. The estimation of the self-shading losses by the irradiation losses simply overestimates the losses; therefore we developed a simulation model to simulate the real energy loss due to shading of the preceding row in a PV system. The model demonstrates that the self-shading energy losses are at commonly used distances between rows from 20 to 40% lower than the irradiation losses at the modules' bottom considering the shading conditions. The self-shading energy loss is studied in the case of Ljubljana, Slovenia which may refer to the whole Central Europe. To estimate the self-shading losses a technology-and with parameter modifications also location-independent empirical equation based on module-to-cell width ratio was derived and validated. © 2011 Elsevier Ltd.

Bodlaj M.,University of Ljubljana
Journal for East European Management Studies | Year: 2012

The purpose of the presented empirical study was to examine the cultural and behavioural adoption of a market orientation as perceived by two groups of managers: general managers and marketing managers. With regard to marketoriented behaviours, a distinction is made between a responsive and a proactive market orientation. Based on a single-informant approach, comparisons between both groups of managers are made by testing invariant latent mean structures. An analysis of 363 companies from a South-east European country reveals that the general managers perceived all components of a market orientation significantly better than the marketing managers.

Kilar V.,University of Ljubljana | Koren D.,University of Ljubljana
Earthquake Engineering and Structural Dynamics | Year: 2010

In the paper a simplified nonlinear method has been applied to the analysis of base-isolated structures. In the first part, a three-linear idealization of the capacity curve is proposed. The initial stiffness is defined based on the first yielding point in the superstructure, whereas the secondary slope depends on the failure mechanism of the superstructure. A consequence is a much more pronounced secondary slope, which does not correspond to the presumptions used in the originally proposed N2 method. A parametric nonlinear dynamic study of single degree of freedom systems with different hardening slopes and damping has been performed for an ensemble of seven EC8 spectrum-compatible artificial accelerograms. It was concluded that, in the long-period range, the equal displacement rule could be assumed also for the proposed systems with non-zero post-yield stiffness. In the second part, the proposed idealization was used for the analysis of isolated RC frame buildings that were isolated with different (lead) rubber-bearing isolation systems. The stiffness of the isolators was selected for three different protection levels and for three different ground motion intensities, which have resulted in elastic as well as moderately and fully damaged superstructure performance levels. Three different lateral load distributions were investigated. It was observed that a triangular distribution, with an additional force at the base, works best in the majority of practical cases. It was concluded that the N2 method can, in general, provide a reasonably accurate prediction of the actual top displacement, as well as of the expected damage to the superstructure. © 2009 John Wiley & Sons, Ltd.

Kastelic M.,University of Ljubljana | Kalyuzhnyi Y.V.,Institute for Condensed Matter Physics | Hribar-Lee B.,University of Ljubljana | Dil K.A.,State University of New York at Stony Brook | Vlachy V.,University of Ljubljana
Proceedings of the National Academy of Sciences of the United States of America | Year: 2015

Protein aggregation is broadly important in diseases and in formulations of biological drugs. Here, we develop a theoretical model for reversible protein-protein aggregation in salt solutions. We treat proteins as hard spheres having square-well-energy binding sites, using Wertheim's thermodynamic perturbation theory. The necessary condition required for such modeling to be realistic is that proteins in solution during the experiment remain in their compact form. Within this limitation our model gives accurate liquid-liquid coexistence curves for lysozyme and γ IIIa-crystallin solutions in respective buffers. It provides good fits to the cloud-point curves of lysozyme in buffer-salt mixtures as a function of the type and concentration of salt. It than predicts full coexistence curves, osmotic compressibilities, and second virial coefficients under such conditions. This treatment may also be relevant to protein crystallization. © 2015, National Academy of Sciences. All rights reserved.

Coh I.,University of Ljubljana | Mackala K.,University School of Physical Education in Wroclaw
Journal of Strength and Conditioning Research | Year: 2013

The aim of this study was to examine the relationship between selected variables of lower extremities explosive power measured via countermovement jump (CMJ) and drop jump (DJ) and sprinting ability over 60-and 100-m dash. Twelve national-level Slovenian sprinters were assigned to 2 groups: elite (n = 6) and subelite (n = 6). The grouping criterion was performance in 60 and 100 m in official competition. Biomechanical parameters of both jumps were measured with the use of bipedal force platform and a system of 9 infraspectral charge-coupled device (CCD) cameras with a 200 Hz frequency. Differences between the groups of sprinters were examined with the use of repeated-measures analysis of variance. In CMJ, the differences (p , 0.05) between the groups were revealed in take off velocity (elites = 3.23 ms21, subelites = 2.94 ms21), height of the jump, vertical velocity of body center of gravity, and the impulse of force in the concentric phase of the jump (concentric impulse: elites = 123.91 Ns; subelites = 108.06 Ns). In the DJ, elite and subelite sprinters differentiated in the realization of movement velocity in the eccentric and concentric phases (take off velocity: elites = 3.18 ms21, subelites = 2.87 ms21; eccentric velocity: elites = 3.05 ms21, subelites = 2.81 ms21). This investigation provides evidence that vertical jumps and DJs are very important tools to meet the demands of sprint training according eccentric-concentric muscular work. The DJ showed better quality than CMJ in the neuromuscular specificity. © 2013 National Strength and Conditioning Association.

We describe a novel approach to investigate and evaluate combined effect of a large number of clinical and pharmacogenetic factors on treatment outcome. We have used this approach to investigate predictors of methotrexate (MTX)-induced adverse events (AEs) leading to treatment discontinuation in rheumatoid arthritis (RA) patients. In total, 333 RA patients were genotyped for 34 polymorphisms in MTX transporters, folate and adenosine pathways. The effect of clinical and pharmacogenetic factors was assessed with penalized regression in the cause-specific Cox proportional hazards model. The predictive capacity was evaluated with the area under time-dependent receiver operating characteristic curve where cross-validation was applied. SLC19A1, ABCG2, ADORA3 and TYMS were associated with discontinuation because of AEs in clinical–pharmacogenetic model. Cross-validation showed that both clinical–pharmacogenetic model and nongenetic model had worthless predictive ability for MTX discontinuation because of AEs. These models could be further improved, either with additional polymorphisms or with epigenetic predictors.The Pharmacogenomics Journal advance online publication, 24 May 2016; doi:10.1038/tpj.2016.36. © 2016 Macmillan Publishers Limited

Saksida A.,University of Ljubljana | Wraber B.,University of Ljubljana | Avsic-Zupanc T.,University of Ljubljana
BMC Infectious Diseases | Year: 2011

Background: Hantaviruses are the causative agents of two zoonotic diseases: hemorrhagic fever with renal syndrome (HFRS) and hantavirus cardiopulmonary syndrome (HCPS). The pathogenesis of HFRS is poorly understood. However, it has been suggested that immune mechanisms, including cytokines, might have an important role in HFRS pathogenesis. Thus, the aim of our study was to investigate cytokine profiles in serum samples of HFRS patients from Slovenia and explore a possible correlation between cytokine levels and disease severity.Methods: Acute-phase serum samples from 52 patients, diagnosed with DOBV infection, and 61 patients, diagnosed with PUUV infection, were included in this study. Patients were divided into two groups - severe or mild - based on disease severity. Levels of IL-10, IL-12, INF-γ and TNF-α were measured in the serum samples with commercial ELISA tests.Results: Increased levels of IL-10, INF-γ, and TNF-α were found in almost all the serum samples tested. On average, higher concentrations were detected in patients infected with DOBV than PUUV. Furthermore, significantly higher levels of IL-10 (P = 0.001) and TNF-α (P = 0.003) were found in patients with a more severe clinical course of disease. The same association between IL-10 (P < 0.001) and TNF-α (P = 0.021), and the severity of the disease was observed also when only patients infected with DOBV were considered. No differences in cytokine concentrations according to disease severity were observed in patients infected with PUUV. Concentrations of serum IL-12 in HFRS patients were in the normal range, however, higher levels were detected in patients infected with PUUV than in patients infected with DOBV.Conclusions: We suggest that imbalance in production of proinflammatory and regulatory cytokines might be in part responsible for a more severe course of HFRS. © 2011 Saksida et al; licensee BioMed Central Ltd.

Repovs G.,University of Ljubljana | Barch D.M.,Washington University in St. Louis
Frontiers in Human Neuroscience | Year: 2012

A growing number of studies have reported altered functional connectivity in schizophrenia during putatively "task-free" states and during the performance of cognitive tasks. However, there have been few systematic examinations of functional connectivity in schizophrenia across rest and different task states to assess the degree to which altered functional connectivity reflects a stable characteristic or whether connectivity changes vary as a function of task demands. We assessed functional connectivity during rest and during three working memory loads of an N-back task (0-back, 1-back, 2-back) among: (1) individuals with schizophrenia (N = 19); (2) the siblings of individuals with schizophrenia (N = 28); (3) healthy controls (N = 10); and (4) the siblings of healthy controls (N = 17). We examined connectivity within and between four brain networks: (1) frontal-parietal (FP); (2) cingulo-opercular (CO); (3) cerebellar (CER); and (4) default mode (DMN). In terms of within-network connectivity, we found that connectivity within the DMN and FP increased significantly between resting state and 0-back, while connectivity within the CO and CER decreased significantly between resting state and 0-back. Additionally, we found that connectivity within both the DMN and FP was further modulated by memory load. In terms of between network connectivity, we found that the DMN became significantly more "anti-correlated" with the FP, CO, and CER networks during 0-back as compared to rest, and that connectivity between the FP and both CO and CER networks increased with memory load. Individuals with schizophrenia and their siblings showed consistent reductions in connectivity between both the FP and CO networks with the CER network, a finding that was similar in magnitude across rest and all levels of working memory load. These findings are consistent with the hypothesis that altered functional connectivity in schizophrenia reflects a stable characteristic that is present across cognitive states. © 2012 Repovš and Barch.

Ficko A.,University of Ljubljana | Boncina A.,University of Ljubljana
Forest Policy and Economics | Year: 2013

We conducted a quantitative study of private forest owner management behavior based on face-to-face interviews with 380 randomly selected private forest owners in Slovenia. Forest owners were asked to rate the relevance of nineteen factors representing information related to the social, ecological, and economic aspects of decision making based on a five-point Likert scale. This information was consolidated into major categories with Principal Component Analysis. Expectation maximization (EM) clustering was used to build a probabilistic private forest owner decision making typology. Six major categories of information determined 64% of the variability in decision making: non-wood goods and services, forest economics, property administration, optimization of wood production, forest protection, and minimum cutting restrictions. EM clustering revealed two decision making types differing in their attitude towards the total economic value of forests: Materialists, whose decisions are mainly related to the extractive value of forests and Non-materialists, who manage for non-extractive value. Full-time farmers, owners living within 2. km of their holdings, and owners who permanently cooperated with the public forest service were much more likely to be Materialists. The uncertainty in private forest owner typology building and the applicability of probabilistic models of private forest owners to end-users is discussed. © 2012 Elsevier B.V.

Pantos M.,University of Ljubljana
Energy | Year: 2011

The paper presents the stochastic optimization algorithm that may eventually be used by electric energy suppliers to coordinate charging of electric-drive vehicles (EDVs) in order to maximize the use of renewable energy in transportation. Due to the stochastic nature of transportation patterns, the Monte Carlo simulation is applied to model uncertainties presented by numerous scenarios. To reduce the problem complexity, the simulated driving patterns are not individually considered in the optimization but clustered into fleets using the GAMS/SCENRED tool. Uncertainties of production of renewable energy sources (RESs) are presented by statistical central moments that are further considered in Hong's 2-point. +. 1 estimation method in order to define estimate points considered in the optimization. Case studies illustrate the application of the proposed optimization in achieving maximal exploitation of RESs in transportation by EDVs. © 2011 Elsevier Ltd.

Batista M.,University of Ljubljana
International Journal of Non-Linear Mechanics | Year: 2015

In this paper, a solution for the equilibrium configuration of an elastic beam subject to three-point bending is given in terms of Jacobi elliptical functions. General equations are derived, and the domain of the solution is established. Several examples that illustrate a use of the solution are discussed. The obtained numerical results are compared with the results of other authors. An approximation formula by which the beam load is given as a polynomial function of beam deflection is also derived. The range of applicability of the approximation is illustrated by numerical examples. © 2014 Elsevier Ltd.

Vidic A.D.,University of Ljubljana
Journal of Professional Issues in Engineering Education and Practice | Year: 2016

Safety is considered as an important area of engineering education, but it is often not addressed adequately in an engineering curriculum. Contents of safety engineering were incorporated in an introductory statistics course through the problem-based learning (PBL) approach. Novices were learning statistical contents via PBL problems from the field of safety engineering. They were divided in two groups according to the partial assessment option they chose: a group with classical assessment and a group with assessment of an independent PBL engineering problem that was designed in accordance with a campaign coordinated by a leading safety agency. In the problem, students analyzed the quality of installation of fire extinguishers in more than 200 buildings, as well as their maintenance. The aim of this study is to find out if the assessment of such a problem can be used to assess students' holistic statistical knowledge, if students can get new insights in the field of safety engineering, and if such assessment suits the assessment criteria for accrediting engineering programs specified by Accreditation Board for Engineering and Technology (ABET criteria). Students' questionnaires also gave information on the students' perception of the difficulty of the PBL approach in both assessment options. © 2015 American Society of Civil Engineers.

Klemenc J.,University of Ljubljana
Reliability Engineering and System Safety | Year: 2015

This article describes how a selected material's fatigue-life-curve model influences the calculated reliability of a structure subjected to a dynamic loading. A uni-axially loaded structural beam with a fully-reversal constant loading amplitude was considered. The reliability for a certain number of cycles-to-failure was calculated as a cross-section of the probability distributions representing the load-amplitude scatter and the scatter of the material's fatigue-life curve. The probability density function (PDF) of the loading amplitude was modelled by a uniform and a Gaussian PDF. The scattered fatigue-life curve was modelled by a conditional two-parametric Weibull's PDF. Its parameters were estimated using two procedures: (i) a two-phase procedure and (ii) a direct procedure. Following the two-phase procedure a conditional PDF of the number of cycles-to-failure was estimated first and then converted into a corresponding conditional PDF of the stress amplitudes. In the direct procedure the conditional PDF of the stress amplitudes was modelled directly from the fatigue-life data. The two procedures were tested on 12 sets of simulated fatigue-life data and a set of experimental fatigue-life data. The two fatigue-life-curve models for the experimental data set were applied for calculating the reliability for the selected structural beam. © 2015 Elsevier Ltd. All rights reserved.

Zgur-Bertok D.,University of Ljubljana
Biochemical Society Transactions | Year: 2012

Colicins are plasmid-encoded bacteriocins active against Escherichia coli and closely related species of Enterobacteriaceae. They promote microbial diversity and genetic diversity in E. coli populations. Colicin synthesis is characteristically repressed by the LexA protein, the key regulator of the SOS response. As colicins are released by cell lysis, generally two LexA dimers binding to two overlapping SOS boxes control untimely expression. Nevertheless, genetic organization of the colicin clusters, additional transcription regulators as well as post-transcriptional mechanisms involving translational efficiency of the lysis and activity genes fine-tune colicin expression and protect against lethality of colicin production. ©The Authors Journal compilation ©2012 Biochemical Society.

Phylogenetic studies show that horizontal gene transfer (HGT) is a significant contributor to genetic variability of prokaryotes, and was perhaps even more abundant during the early evolution. Hitherto, research of natural HGT has mainly focused on three mechanisms of DNA transfer: conjugation, natural competence, and viral transduction. This paper discusses the feasibility of a fourth such mechanism - cell electroporation and/or electrofusion triggered by atmospheric electrostatic discharges (lightnings). A description of electroporation as a phenomenon is followed by a review of experimental evidence that electroporation of prokaryotes in aqueous environments can result in release of non-denatured DNA, as well as uptake of DNA from the surroundings and transformation. Similarly, a description of electrofusion is followed by a review of experiments showing that prokaryotes devoid of cell wall can electrofuse into hybrids expressing the genes of their both precursors. Under sufficiently fine-tuned conditions, electroporation and electrofusion are efficient tools for artificial transformation and hybridization, respectively, but the quantitative analysis developed here shows that conditions for electroporation-based DNA release, DNA uptake and transformation, as well as for electrofusion are also present in many natural aqueous environments exposed to lightnings. Electroporation is thus a plausible contributor to natural HGT among prokaryotes, and could have been particularly important during the early evolution, when the other mechanisms might have been scarcer or nonexistent. In modern prokaryotes, natural absence of the cell wall is rare, but it is reasonable to assume that the wall has formed during a certain stage of evolution, and at least prior to this, electrofusion could also have contributed to natural HGT. The concluding section outlines several guidelines for assessment of the feasibility of lightning-triggered HGT. © 2013 Elsevier B.V.

Petrovic D.,University of Ljubljana
BioMed Research International | Year: 2013

Several candidate genes have been so far implicated in the pathogenesis of proliferative diabetic retinopathy (PDR) in subjects with type 2 diabetes. Since the principal pathogenetic mechanisms for diabetic retinopathy (DR) and PDR are different, the main pathogenetic mechanism in DR is increased vascular permeability, whereas in PDR the crucial pathogenetic mechanisms are fibrosis and neoangiogenesis. Due to that fact, different candidate genes are expected to be involved in the development of either DR or PDR. None of the candidate genes, however, can be fully and solely responsible for the development of PDR and for DR progression into PDR. Epigenetic mechanisms are expected to be involved in the pathogenesis of PDR as well. Gene polymorphisms responsible for PDR and epigenetic mechanisms responsible for PDR are reviewed in this paper. © 2013 Daniel Petrovič.

Perse M.,University of Ljubljana
BioMed Research International | Year: 2013

There is a growing support for the concept that reactive oxygen species, which are known to be implicated in a range of diseases, may be important progenitors in carcinogenesis, including colorectal cancer (CRC). CRC is one of the most common cancers worldwide, with the highest incidence rates in western countries. Sporadic human CRC may be attributable to various environmental and lifestyle factors, such as dietary habits, obesity, and physical inactivity. In the last decades, association between oxidative stress and CRC has been intensively studied. Recently, numerous genetic and lifestyle factors that can affect an individual's ability to respond to oxidative stress have been identified. The aim of this paper is to review evidence linking oxidative stress to CRC and to provide essential background information for accurate interpretation of future research on oxidative stress and CRC risk. Brief introduction of different endogenous and exogenous factors that may influence oxidative status and modulate the ability of gut epithelial cells to cope with damaging metabolic challenges is also provided. © 2013 Martina Perše.

Acimovic J.,University of Ljubljana | Rozman D.,University of Ljubljana
Molecules | Year: 2013

Cholesterol synthesis is a ubiquitous and housekeeping metabolic pathway that leads to cholesterol, an essential structural component of mammalian cell membranes, required for proper membrane permeability and fluidity. The last part of the pathway involves steroidal triterpenes with cholestane ring structures. It starts by conversion of acyclic squalene into lanosterol, the first sterol intermediate of the pathway, followed by production of 20 structurally very similar steroidal triterpene molecules in over 11 complex enzyme reactions. Due to the structural similarities of sterol intermediates and the broad substrate specificity of the enzymes involved (especially sterol-Δ24- reductase; DHCR24) the exact sequence of the reactions between lanosterol and cholesterol remains undefined. This article reviews all hitherto known structures of post-squalene steroidal triterpenes of cholesterol synthesis, their biological roles and the enzymes responsible for their synthesis. Furthermore, it summarises kinetic parameters of enzymes (Vmax and Km) and sterol intermediate concentrations from various tissues. Due to the complexity of the post-squalene cholesterol synthesis pathway, future studies will require a comprehensive meta-analysis of the pathway to elucidate the exact reaction sequence in different tissues, physiological or disease conditions. A major reason for the standstill of detailed late cholesterol synthesis research was the lack of several steroidal triterpene standards. We aid to this efforts by summarizing commercial and laboratory standards, referring also to chemical syntheses of meiosisactivating sterols. © 2013 by the authors.

Berlec A.,Jozef Stefan Institute | Strukelj B.,Jozef Stefan Institute | Strukelj B.,University of Ljubljana
Journal of Industrial Microbiology and Biotechnology | Year: 2013

Almost all of the 200 or so approved biopharmaceuticals have been produced in one of three host systems: the bacterium Escherichia coli, yeasts (Saccharomyces cerevisiae, Pichia pastoris) and mammalian cells. We describe the most widely used methods for the expression of recombinant proteins in the cytoplasm or periplasm of E. coli, as well as strategies for secreting the product to the growth medium. Recombinant expression in E. coli influences the cell physiology and triggers a stress response, which has to be considered in process development. Increased expression of a functional protein can be achieved by optimizing the gene, plasmid, host cell, and fermentation process. Relevant properties of two yeast expression systems, S. cerevisiae and P. pastoris, are summarized. Optimization of expression in S. cerevisiae has focused mainly on increasing the secretion, which is otherwise limiting. P. pastoris was recently approved as a host for biopharmaceutical production for the first time. It enables high-level protein production and secretion. Additionally, genetic engineering has resulted in its ability to produce recombinant proteins with humanized glycosylation patterns. Several mammalian cell lines of either rodent or human origin are also used in biopharmaceutical production. Optimization of their expression has focused on clonal selection, interference with epigenetic factors and genetic engineering. Systemic optimization approaches are applied to all cell expression systems. They feature parallel high-throughput techniques, such as DNA microarray, next-generation sequencing and proteomics, and enable simultaneous monitoring of multiple parameters. Systemic approaches, together with technological advances such as disposable bioreactors and microbioreactors, are expected to lead to increased quality and quantity of biopharmaceuticals, as well as to reduced product development times. © 2013 Society for Industrial Microbiology and Biotechnology.

Hafner A.,University of Ljubljana | Obermajer N.,Jozef Stefan Institute | Kos J.,University of Ljubljana | Kos J.,Jozef Stefan Institute
Biochemical Journal | Year: 2012

γ-Enolase, a glycolytic enzyme, is expressed specifically in neurons. It exerts neurotrophic activity and has been suggested to regulate growth, differentiation, survival and regeneration of neurons. In the present study, we investigated the involvement of γ -enolase in PI3K (phosphoinositide 3-kinase)/Akt and MAPK (mitogen-activated protein kinase)/ERK (extracellularsignal- regulated kinase) signalling, the two pathways triggered predominantly by neurotrophic factors. Whereas the PI3K/Akt pathway, rather than the MAPK/ERK pathway, is involved in γ -enolase-enhanced cell survival, γ -enolase-stimulated neurite outgrowth requires both pathways, i.e. the activation of both PI3K and ERK1/2, leading to subsequent expression of the growth-cone-specific protein GAP-43 (growth-associated protein of 43 kDa). MEK (MAPK/ERK kinase) and PI3K inhibition blocked or attenuated the neurite outgrowth associated with dynamic remodelling of the actin-based cytoskeleton. We show that γ -enolase-mediated PI3K activation regulates RhoA kinase, a key regulator of actin cytoskeleton organization. Moreover, the inhibition of RhoA downstream effector ROCK (Rho-associated kinase) results in enhanced γ -enolase-induced neurite outgrowth, accompanied by actin polymerization and its redistribution to growth cones. Our results show that γ -enolase controls neuronal survival, differentiation and neurite regeneration by activating the PI3K/Akt and MAPK/ERK signalling pathways, resulting in downstream regulation of the molecular and cellular processes of cytoskeleton reorganization and cell remodelling, activation of transcriptional factors and regulation of the cell cycle. ©The Authors Journal compilation © 2012 Biochemical Society.

Trdan U.,University of Ljubljana | Grum J.,University of Ljubljana
Corrosion Science | Year: 2012

Laser shock peening (LSP) without ablative coating at various power densities was applied to AA6082 aluminium alloy to investigate corrosion behaviour in a 0.6M NaCl solution. Cyclic polarisation results showed enhanced passivity with corrosion current reduction by as much as a factor of 12, compared to the untreated specimen. Additionally, EIS after 24h confirmed almost seven times higher polarisation resistance after LSP, compared to the untreated specimen (45 and 6.7kΩcm 2). XPS analysis indicated Al 2O 3 enrichment, which contributed to higher corrosion resistance with reduced anodic dissolution of the LSP-treated surface due to plasma ablation and shock waves. © 2012 Elsevier Ltd.

Gosar A.,University of Ljubljana
Natural Hazards and Earth System Sciences | Year: 2010

The town of Kobarid is located in one of three areas with the highest seismic hazard in Slovenia. It was hit by several 1976-1977 Friuli sequence earthquakes and recently by the 1998 and 2004 Krn Mountains earthquakes which caused damage of intensity up to VII EMS-98 scale. The town is located in a small basin filled with heterogeneous glaciofluvial Quaternary sediments in which site effects due to soft sediments are expected. The existing microzonation which is based on surface geological data only is inadequate, and no borehole or geophysical data are available in the basin that would allow a modelling approach of site effects assessment. The microtremor horizontal-to-vertical spectral ratio (HVSR) method was therefore applied in order to assess the fundamental frequency of the sediments. Investigations were performed on a 100×100 m dense grid and 106 free-field measurements acquired. Clear HVSR peaks were obtained in the majority of the surveyed area. The eastern part of the basin is characterized by two well separated peaks which indicate distinct shallow and deep impedance contrasts. The iso-frequency map of sediments shows a distribution in a broad range of 1.8-22.2 Hz. The observed frequencies can be related to the total thickness of Quaternary sediments (sand, gravel) in the western part of the basin only. They are deposited over bedrock built of Cretaceous flysch. In the eastern part the obtained fundamental frequencies are influenced by the presence of a shallow conglomerate layer inside sandy gravel or lacustrine chalk. The extent of these layers was not known before. Microtremor measurements were also performed inside 19 characteristic buildings of various heights (from two to four stories), and longitudinal and transverse fundamental frequencies determined from amplitude spectra. A potential of soil-structure resonance was assessed by comparing building frequencies with the free-field sediments frequencies derived from the iso-frequency map. For two surveyed buildings a high danger of soil-structure resonance was assessed and for three buildings the danger was of medium level. The building resonant frequency of two-and three-story houses, which prevail in the area, spans the range 4-11 Hz, with an average value of 7.7 Hz. The danger of soil-structure resonance should be therefore sought in this frequency range. Since the majority of Kobarid area is characterized by lower (W part) or higher (E part) frequencies, the danger exist mainly in a relatively narrow transition zone. © 2011 Author(s).

Mohoric I.,Hidria Institute for Materials and Technology | Sebenik U.,University of Ljubljana
Polymer | Year: 2011

Batch anionic ring-opening polymerization of octamethylcyclotetrasiloxane in emulsion using nonionic and cationic emulsifiers was studied. The concentration of emulsifiers was set above their critical micelle concentration. Effects of emulsifier concentration, nonionic/cationic emulsifier ratio and cationic emulsifier/initiator (KOH) ratio on the kinetics, average particle size and distribution and on the average molecular weight and distribution were investigated and discussed. At the beginning of the polymerization, empty micelles, active micelles (polymer particles) and monomer droplets co-exist in emulsion. The transport of monomer from monomer droplets toward empty micelles was confirmed by monomer droplets and empty micelles disappearance and by formation of smaller particles. The transport of monomer from monomer droplets toward polymer particles was not confirmed, since the average polymer particle size did not increase during polymerization. It was proposed, that at lower conversions, monomer diffuses from polymer particle interior to particle surface, while at higher conversions, the monomer diffuses from larger to smaller polymer particles. Emulsifier concentration, nonionic/cationic emulsifier ratio and cationic emulsifier/KOH ratio have an evident effect on the kinetics and on the average molecular weight, thus demonstrating that cationic emulsifier participates to the initiation reaction. © 2010 Elsevier Ltd. All rights reserved.

Fajfar P.,University of Ljubljana | Dolsek M.,University of Ljubljana
Earthquake Engineering and Structural Dynamics | Year: 2012

In the presented practice-oriented probabilistic approach for the seismic performance assessment of building structures, the SAC-FEMA method, which is a part of the broader PEER probabilistic framework and permits probability assessment in closed form, is combined with the pushover-based N2 method. The most demanding part of the PEER probabilistic framework, that is incremental dynamic analysis, is replaced by the much simpler N2 method, which requires considerably less input data and much less computational time, but which can, nevertheless, often provide: acceptable estimates for the mean values of the structural response. Using some additional simplifying assumptions that are consistent with seismic code procedures, an explicit equation for a quick estimation of the annual probability of "failure" (i.e. the probability of exceeding the near collapse limit state) of a structure can be derived, which is appropriate for practical applications, provided that predetermined default values for the dispersion measures are available. In the paper, this simplified approach is summarized and applied to the estimation of the "failure" probability of reinforced concrete frame buildings representing both old structures, not designed for earthquake resistance, and new structures designed according to Eurocode 8. The results of the analyses indicate a high probability of the "failure" of buildings, which have not been designed for seismic loads. For a building designed according to a modern code, the conservatively determined probability of "failure" is about 30 times less but still significant (about 1% over the lifetime of the structure). © 2011 John Wiley & Sons, Ltd.

Zalohar J.,University of Ljubljana
Journal of Structural Geology | Year: 2012

Classical methods for the fault-slip data analysis generally assume that the slip direction along different faults is independent. However, wedge faulting can often be observed in nature, characterized by the interaction between intersecting faults, which produces a slip direction subparallel to the common intersection direction among the faults. In this article the wedge faulting is described within the frame of the Cosserat theory. We show that this type of faulting is possible both in the classical (Cauchy) continuum as well as in the Cosserat continuum. In the classical continuum, there are two possible optimal interacting subsystems of faults with orientations symmetrically aligned with respect to the kinematic axes of the macrostrain tensor. In the Cosserat continuum these subsystems are not symmetric, because they do not accommodate the same amount of deformation. One of them is dominant and accommodates a larger amount of deformation than the other (weaker) subsystem. In addition, the non-optimal faults with orientations close to the dominant optimal interacting subsystem can also interact, forming an even more complex asymmetric interacting system. © 2012 Elsevier Ltd.

Kreslin M.,University of Ljubljana | Fajfar P.,University of Ljubljana
Bulletin of Earthquake Engineering | Year: 2012

The extended N2 method has been developed, which takes into account higher mode effects both in plan and in elevation. The extension is based on the assumption that the structure remains in the elastic range when vibrating in higher modes. The seismic demand in terms of displacements and storey drift can be obtained by combining the results of basic pushover analysis and those of standard elastic modal analysis. In the paper, the proposed procedure was summarized and applied to a test example which represents an actual 8-storey reinforced concrete building. The results obtained by the extended N2 method were compared with the results of nonlinear response history analysis and basic N2 analysis without the consideration of higher modes. The extended N2 method was able to provide fair, conservative estimates of response in the case of the test example. In comparison to the basic N2 method, the prediction of seismic demand was greatly improved in the upper part of the building and at the flexible edges. © 2011 Springer Science+Business Media B.V.

High frequency ground penetrating radar (GPR) is usually applied for cavities detection in a shallow subsurface of karst areas to prevent geotechnical hazards. For specific projects, such as tunnel construction, it is important to detect also larger voids at medium depth range. However, dimensions of classical rigid low frequency antennas seriously limit their applicability in a rough terrain with dense vegetation commonly encountered in a karst. In this study recently developed 50 MHz antennas designed in a tube form were tested to detect cave gallery at the depth between 12 m and 60 m. The Divača cave was selected because of a wide range of depths under the surface, possibility of unknown galleries in the vicinity and a rough terrain surface typical for Slovenian karst. Seven GPR profiles were measured across the main gallery of the cave and additional four profiles NE of the cave entrance where no galleries are known. Different acquisition and processing parameters were analysed together with the data resolution issues. The main gallery of the cave was clearly imaged in the part where the roof of the gallery is located at the depth from 10 m to 30 m. The width of the open space is mainly around 10 m. Applied system was not able to detect the gallery in the part where it is located deeper than 40 m, but several shallower cavities were discovered which were unknown before. The most important result is that the profiles acquired NE of the cave entrance revealed very clearly the existence of an unknown gallery which is located at the depth between 15 m and 22 m and represents the continuation of the Divača cave. Access to this gallery is blocked by the sediment fill in the entrance shaft of the cave. The results of the study are important also for future infrastructure projects which will involve construction of tunnels through karstified limestone and for speleological investigations to direct the research efforts.

Gramec D.,University of Ljubljana | Peterlin Masic L.,University of Ljubljana | Sollner Dolenc M.,University of Ljubljana
Chemical Research in Toxicology | Year: 2014

Thiophene is a five-membered, sulfur-containing heteroaromatic ring commonly used as a building block in drugs. It is considered to be a structural alert, as its metabolism can lead to the formation of reactive metabolites. Thiophene S-oxides and thiophene epoxides are highly reactive electrophilic thiophene metabolites whose formation is cytochrome P450-dependent. These reactive thiophene-based metabolites are quite often responsible for drug-induced hepatotoxicity. Tienilic acid is an example of a thiophene-based drug that was withdrawn from the market after only a few months of use, due to severe cases of immune hepatitis. However, inclusion of the thiophene moiety in drugs does not necessarily result in toxic effects. The presence of other, less toxic metabolic pathways, as well as an effective detoxification system in our body, protects us from the bioactivation potential of the thiophene ring. Thus, the presence of a structural alert itself is insufficient to predict a compounds toxicity. The question therefore arises as to which factors significantly influence the toxicity of thiophene-containing drugs. There is no easy way to answer this question. However, the findings presented here indicate that, for a number of reasons, daily dose and alternative metabolic pathways are important factors when predicting toxicity and will therefore be discussed together with examples. © 2014 American Chemical Society.

Mahnic V.,University of Ljubljana
World Transactions on Engineering and Technology Education | Year: 2015

Since most of the core software engineering courses do not pay enough attention to agile software development, a software engineering capstone course represents an appropriate place for more in-depth treatment of this topic. In this article, the evolution of the software engineering capstone course at the University of Ljubljana is described since its conception in the 2008/09 academic year till now. The course requires students to develop a quasi-real project strictly following Scrum, which is the most widespread agile method. Additionally, the course design enables the conduct of studies that contribute to empirical evidence regarding agile processes. The article explains the reasons for introducing Scrum, presents the course design, describes some examples of empirical studies that were conducted within the course, and outlines the course upgrade with lean approaches to software development. Students' opinions about the course are overwhelmingly positive, indicating that the course is interesting and beneficial to their employability and professional career. © 2015 WIETE.

Dolsek M.,University of Ljubljana
Structure and Infrastructure Engineering | Year: 2012

A simplified method for seismic risk assessment with consideration of aleatory and epistemic uncertainties is proposed based on the widely used closed-form solution for estimating the mean annual frequency of exceeding a limit state (LS). The method for the determination of fragility parameters involves a non-linear static analysis of a set of structural models, which is defined by utilising Latin hypercube sampling, and non-linear dynamic analyses of equivalent single degree-of-freedom models. The set of structural models captures the epistemic uncertainties, whereas the aleatory uncertainty due to the random nature of the ground motion is, as usual, simulated by a set of ground motion records. Although the method is very simple to implement, it goes beyond the widely used assumption of independent effects due to aleatory and epistemic uncertainty. Thus, epistemic uncertainty has a potential influence on both fragility parameters, and not only on dispersion, as has been assumed in some other approximate methods. The proposed method is applied to an example of a four-storey reinforced concrete building, where it is shown that the effects of epistemic uncertainties, in addition to aleatory uncertainty, increase with the severity of the LS, so that, for the near collapse LS, the risk with consideration of both sources of uncertainty is more than double if compared to the risk, which was determined solely by the consideration of aleatory uncertainty. © 2012 Copyright Taylor and Francis Group, LLC.

Perse M.,University of Ljubljana | Cerar A.,University of Ljubljana
Journal of Biomedicine and Biotechnology | Year: 2011

The dimethyhydrazine (DMH) or azoxymethane (AOM) model is a well-established, well-appreciated, and widely used model of experimental colon carcinogenesis. It has many morphological as well as molecular similarities to human sporadic colorectal cancer (CC), which are summarized and discussed in this paper. In addition, the paper combines present knowledge of morphological and molecular features in the multistep development of CC recognized in the DMH/AOM rat model. This understanding is necessary in order to accurately identify and interpret alterations that occur in the colonic mucosa when evaluating natural or pharmacological compounds in DMH/AOM rat colon carcinogenesis. The DMH/AOM model provides a wide range of options for investigating various initiating and environmental factors, the role of specific dietary and genetic factors, and therapeutic options in CC. The limitations of this model and suggested areas in which more research is required are also discussed. © 2011 Martina Pere and Anton Cerar.

Cresnar B.,University of Ljubljana | Petric S.,University of Ljubljana
Biochimica et Biophysica Acta - Proteins and Proteomics | Year: 2011

Cytochrome P450 monooxygenases of fungi are involved in many essential cellular processes and play diverse roles. The enzymes catalyze the conversion of hydrophobic intermediates of primary and secondary metabolic pathways, detoxify natural and environmental pollutants and allow fungi to grow under different conditions. Fungal genome sequencing projects have enabled the annotation of several thousand novel cytochromes P450, many of which constitute new families. This review presents the characteristics of fungal cytochrome P450 systems and updates information on the functions of characterized fungal P450 monooxygenases as well as outlines the currently used strategies for determining the function of the many putative P450 enzymes. © 2010 Elsevier B.V. All rights reserved.

Jakopin Z.,University of Ljubljana | Dolenc M.S.,University of Ljubljana
Current Medicinal Chemistry | Year: 2010

The saccharin ring system has gained considerable attention in the past decades, especially in the field of medicinal chemistry. The wide applicability of saccharin derivatives remains the driving force behind the constant development of novel routes and methods that provide new access to the construction of saccharin. Since the functionalization of this heterocycle has proved difficult, except for N- and O-alkylation, novel strategic approaches are much sought-after and thus constitute a great value to any medicinal chemist. In addition to the synthetic novelties introduced into the synthesis and functionalization of this particular heterocycle, the numerous newly discovered biological activities of saccharin and its derivatives are also reviewed. Saccharin may be considered to constitute a privileged framework on account of its role as a key structural element in several biologically active compounds ranging from enzyme inhibitors to receptor ligands and beyond. © 2010 Bentham Science Publishers Ltd.

BACKGROUND: Longest bipolar length of the kidney graft is routinely measured for ultrasonographic assessment of graft size (GS), although the value of the graft length remains unclear. PATIENTS AND METHODS: In a single-center, observational study involving 319 deceased-donor kidney transplant recipients, we assessed variations in absolute and adjusted GS (corrected for body surface area) between 1 and 12 months after transplantation ([INCREMENT]GS1m→12m). We tested whether variations in GS during the first year were predictive of the composite outcome of a reduction of 50% or more in the estimated glomerular filtration rate or end-stage graft failure. RESULTS: At 1 year after transplantation, 121 patients (38%) had a decrease in GS ([INCREMENT]GS1m→12m <0), and 198 patients (62%) had an increase in GS ([INCREMENT]GS1m→12m ≥0). After a median follow-up of 53 months, 41 patients with a decrease in GS reached the composite outcome as compared with 12 patients with an increase in GS (34% and 6%, respectively; P < 0.001). Areas under the receiver operating characteristics curves of absolute and adjusted [INCREMENT]GS1m→12m for composite outcome were 0.81 (95% confidence interval [95% CI], 0.74-0.88) and 0.78 (95% CI, 0.70-0.86), respectively. In multivariate analysis, the risk of the composite outcome was significantly higher among patients with a decrease in GS during the first year after transplantation (hazard ratio, 4.55; 95% CI, 2.35-8.81; P < 0.001). CONCLUSIONS: A decrease in kidney GS during the first year after transplantation, as compared with an increase in GS, is a powerful predictor of subsequent graft dysfunction or end-stage graft failure.This is an open-access article distributed under the terms of the Creative Commons Attribution-NonCommercial-NoDerivatives 3.0 License, where it is permissible to download and share the work provided it is properly cited. The work cannot be changed in any way or used commercially. http://creativecommons.org/licenses/by-nc-nd/3.0. Copyright © 2015 Wolters Kluwer Health, Inc. All rights reserved.

Stegnar M.,University of Ljubljana
Clinical Chemistry and Laboratory Medicine | Year: 2010

Thrombophilia can be identified in about half of all patients presenting with venous thromboembolism (VTE). Thrombophilia screening for various indications has increased tremendously, but whether the results of such tests help in the clinical management of patients is uncertain. Here, current recommendations for thrombophilia screening in selected groups of patients, and considerations whether other high-risk subjects should be tested are reviewed. The methods for determination of the most common thrombophilic defects (antithrombin, protein C, protein S deficiencies, Factor V Leiden and prothrombin G20210A) associated with strong to moderate risk of VTE are described, indicating the timing and location of thrombophilia screening. Circumstances when a positive result of thrombophilia screening helps clinicians decide if adjustments of the anticoagulant regime are needed are discussed. Finally, psychological, social and ethical dilemmas associated with thrombophilia screening are indicated. Clin Chem Lab Med 2010;48:S105-13. © 2010 by Walter de Gruyter Berlin New York.

Poljsak B.,University of Ljubljana | Dahmane R.,University of Ljubljana
Dermatology Research and Practice | Year: 2012

Human skin is constantly directly exposed to the air, solar radiation, environmental pollutants, or other mechanical and chemical insults, which are capable of inducing the generation of free radicals as well as reactive oxygen species (ROS) of our own metabolism. Extrinsic skin damage develops due to several factors: ionizing radiation, severe physical and psychological stress, alcohol intake, poor nutrition, overeating, environmental pollution, and exposure to UV radiation (UVR). It is estimated that among all these environmental factors, UVR contributes up to 80%. UV-induced generation of ROS in the skin develops oxidative stress, when their formation exceeds the antioxidant defence ability of the target cell. The primary mechanism by which UVR initiates molecular responses in human skin is via photochemical generation of ROS mainly formation of superoxide anion (O 2 - ), hydrogen peroxide (H 2O2), hydroxyl radical (OH), and singlet oxygen (O 2 1). The only protection of our skin is in its endogenous protection (melanin and enzymatic antioxidants) and antioxidants we consume from the food (vitamin A, C, E, etc.). The most important strategy to reduce the risk of sun UVR damage is to avoid the sun exposure and the use of sunscreens. The next step is the use of exogenous antioxidants orally or by topical application and interventions in preventing oxidative stress and in enhanced DNA repair. © 2012 Borut Poljšak and Raja Dahmane.

Bratkovic T.,University of Ljubljana
Cellular and Molecular Life Sciences | Year: 2010

Phage display, the presentation of (polypeptides as fusions to capsid proteins on the surface of bacterial viruses, celebrates its 25th birthday in 2010. The technique, coupled with in vitro selection, enables rapid identification and optimization of proteins based on their structural or functional properties. In the last two decades, it has advanced tremendously and has become widely accepted by the scientific community. This by no means exhaustive review aims to inform the reader of the key modifications in phage display. Novel display formats, innovative library designs and screening strategies are discussed. I will also briefly review some recent uses of the technology to illustrate its incredible versatility.

Kitanovski A.,University of Ljubljana | Egolf P.W.,University of Applied Sciences and Arts Western Switzerland | Poredos A.,University of Ljubljana
International Journal of Refrigeration | Year: 2012

In this article a technical-economic analysis of rotary magnetic liquid chillers is presented. The technical part comprises studies on different magnetocaloric regenerator geometries and different operating parameters. The results are presented by correlations of the Coefficient of Performance (COP) and the cooling capacity of a magnetic chiller. The analysis is based on applications with two different working fluids. The results reveal that magnetic chillers can be more efficient than conventional compressor-based chillers. However, the investment costs for magnetic chillers are higher. A discussion on the cost break-down and possible cost reductions is outlined. Some ideas for future R&D in the field of magnetic refrigeration are given. © 2012 Elsevier Ltd and IIR. All rights reserved.

Gilbert R.J.C.,University of Oxford | Mikelj M.,University of Ljubljana | Dalla Serra M.,National Research Council Italy | Froelich C.J.,NorthShore University HealthSystem Research Institute | And 2 more authors.
Cellular and Molecular Life Sciences | Year: 2013

Recent work on the MACPF/CDC superfamily of pore-forming proteins has focused on the structural analysis of monomers and pore-forming oligomeric complexes. We set the family of proteins in context and highlight aspects of their function which the direct and exclusive equation of oligomers with pores fails to explain. Starting with a description of the distribution of MACPF/CDC proteins across the domains of life, we proceed to show how their evolutionary relationships can be understood on the basis of their structural homology and re-evaluate models for pore formation by perforin, in particular. We furthermore highlight data showing the role of incomplete oligomeric rings (arcs) in pore formation and how this can explain small pores generated by oligomers of proteins belonging to the family. We set this in the context of cell biological and biophysical data on the proteins' function and discuss how this helps in the development of an understanding of how they act in processes such as apicomplexan parasites gliding through cells and exiting from cells. © 2012 Springer Basel AG.

Simic R.,University of Ljubljana | Kalin M.,University of Ljubljana
Applied Surface Science | Year: 2013

Fatty acids are known to affect the friction and wear of steel contacts via adsorption onto the surface, which is one of the fundamental boundary-lubrication mechanisms. The understanding of the lubrication mechanisms of polar molecules on diamond-like carbon (DLC) is, however, still insufficient. In this work we aimed to find out whether such molecules have a similar effect on DLC coatings as they do on steel. The adsorption of hexadecanoic acid in various concentrations (2-20 mmol/l) on DLC was studied under static conditions using an atomic force microscope (AFM). The amount of surface coverage of the adsorbed fatty-acid molecules was analysed. In addition, tribological tests were performed to correlate the wear and friction behaviours in tribological contacts with the adsorption of molecules on the surface under static conditions. A good correlation between the AFM results and the tribological behaviour was observed. We confirmed that fatty acids can adsorb onto the DLC surfaces and are, therefore, potential boundary-lubrication agents for DLC coatings. The adsorption of the fatty acid onto the DLC surfaces reduces the wear of the coatings, but it is less effective in reducing the friction. Tentative adsorption mechanisms that include an environmental species effect, a temperature effect and a tribochemical effect are proposed for DLC and steel surfaces based on our results and few potential mechanisms found in literature. © 2013 Elsevier B.V. All rights reserved.

Barlovic D.P.,University of Ljubljana | Soro-Paavonen A.,University of Helsinki | Jandeleit-Dahm K.A.M.,Baker IDI Heart and Diabetes Institute | Jandeleit-Dahm K.A.M.,Monash University
Clinical Science | Year: 2011

Diabetes is characterized by accelerated atherosclerosis with widely distributed vascular lesions. An important mechanism by which hyperglycaemia contributes to vascular injury is through the extensive intracellular and extracellular formation of AGEs (advanced glycation end products). AGEs represent a heterogeneous group of proteins, lipids and nucleic acids, irreversibly cross-linked with reducing sugars. AGEs are implicated in the atherosclerotic process, either directly or via receptor-mediated mechanisms, the most extensively studied receptor being RAGE (receptor for AGEs). The AGE-RAGE interaction alters cellular signalling, promotes gene expression and enhances the release of pro-inflammatory molecules. It elicits the generation of oxidative stress in numerous cell types. The importance of the AGE-RAGE interaction and downstream pathways leading to injurious effects as a result of chronic hyperglycaemia in the development, progression and instability of diabetic atherosclerotic lesions has been amply demonstrated in animal studies. Moreover, the deleterious link of AGEs with diabetic vascular complications has been suggested in many human studies. In the present review, our current understanding of their role as an important mediator of vascular injury through the various stages of atherosclerosis in diabetes will be reviewed and critically assessed. © The Authors Journal compilation. © 2011 Biochemical Society.

Kisspeptin, a regulator of reproductive function and puberty in mammals, is expressed in the rostral periventricular nucleus (AVPV) and arcuate nucleus (Arc) and its expression is at least partially regulated by estradiol in rodents. The aim of the present study was to determine contributions of genetic factors and gonadal steroid hormones in the sexual differentiation of kisspeptin immunoreactive cell populations in the AVPV and Arc during postnatal development using agonadal Steroidogenic factor-1 knockout (SF-1 KO) mice. To examine effects of gonadal hormones on pubertal development of kisspeptin neurons, SF-1 KO mice were treated with estradiol benzoate (EB) from P25 to P36 and their brains examined at P36. No sex differences were observed in SF-1 KO mice during postnatal development and after treatment with EB, which failed to increase the number of kisspeptin- ir cells at P36 in SF-1 KO mice to the levels found in WT control females. This suggests that specific time periods of estradiol actions or other factors are needed for sexual differentiation of the pattern of immunoreactive kisspeptin in the AVPV. Kisspeptin immunoreactivity in the Arc was significantly higher in gonadally intact WT and SF-1 KO females than male mice at P36 during puberty. Further, in WT and SF-1 KO females, but not in males, adult levels were reached at P36. This suggests that maturation of the kisspeptin system in the Arc differs between sexes and is regulated by gonad- independent mechanisms. © 2015 S. Karger AG, Basel Copyright © 2015, S. Karger AG. All rights reserved.

Sirca S.,University of Ljubljana
Few-Body Systems | Year: 2010

The 3He nucleus is a calculable nuclear system (Carlson and Schiavilla in Rev Mod Phys 70:743, 1998) for which our theoretical understanding can be compared with data to an increasingly accurate degree. In turn, the theory faces extensive precise data sets from a series of experiments. Two laboratories are leading the way: MAMI/A1 and the Thomas Jefferson National Accelerator Facility (TJNAF). This paper reviews some of the outstanding current experimental efforts with (polarized or unpolarized) electron scattering on (polarized or unpolarized) 3He targets in these laboratories. © Springer-Verlag 2009.

Stuhec M.,Ormoz Psychiatric hospital | Munda B.,University of Ljubljana | Svab V.,University of Ljubljana | Locatelli I.,University of Ljubljana
Journal of Affective Disorders | Year: 2015

Abstract Objectives There is a lack of comparative effectiveness research among attention deficit hyperactivity disorder (ADHD) drugs in terms of efficacy and acceptability, where bupropion is compared with atomoxetine, lisdexamfetamine and methylphenidate. The main aim of this work was to compare the efficacy and acceptability of these drugs in children and adolescents using a metaanalysis. Methods A literature search was conducted to identify double-blind, placebo-controlled, noncrossover studies of ADHD. PubMed/Medline and Clinicaltrials.gov were searched. Comparative drug efficacy to placebo was calculated based on the standardized mean difference (SMD), while the comparative drug acceptability (all cause discontinuation) to placebo was estimated on the odds ratio (OR). Results In total 28 trials were included in the meta-analysis. Efficacy in reducing ADHD symptoms compared to placebo was small for bupropion (SMD=-0.32, 95% CI; -0.69, 0.05), while modest efficacy was shown for atomoxetine (SMD=-0.68, 95% CI; -0.76, -0.59) and methylphenidate (SMD=-0.75, 95% CI; -0.98, -0.52) and high efficacy was observed for lisdexamfetamine (SMD=-1.28, 95% CI; -1.84, -0.71). Compared to placebo treatment discontinuation was statistically significantly lower for methylphenidate (OR=0.35, 95% CI; 0.24, 0.52), while it was not significantly different for atomoxetine (OR=0.91, 95% CI; 0.66, 1.24), lisdexamfetamine (OR=0.60, 95% CI, 0.22, 1.65), and bupropion (OR=1.64, 95% CI; 0.5, 5.43). Limitations The heterogeneity was high, except in atomoxetine trials. The crossover studies were excluded. The effect sizes at specific time points were not computed. Studies with comorbid conditions, except those reporting on oppositional defiant disorder, were also excluded. All studies involving MPH were combined. Conclusions The results suggest that lisdexamfetamine has the best benefit risk balance and has promising potential for treating children and adolescents with ADHD. More research is needed for a better clinical evaluation of bupropion. © 2015 Elsevier B.V. All rights reserved.

Repovs G.,University of Ljubljana | Barch D.M.,Washington University in St. Louis
Frontiers in Human Neuroscience | Year: 2012

A growing number of studies have reported altered functional connectivity in schizophrenia during putatively "task-free" states and during the performance of cognitive tasks. However, there have been few systematic examinations of functional connectivity in schizophrenia across rest and different task states to assess the degree to which altered functional connectivity reflects a stable characteristic or whether connectivity changes vary as a function of task demands. We assessed functional connectivity during rest and during three working memory loads of an N-back task (0-back, 1-back, 2-back) among: (1) individuals with schizophrenia (N = 19); (2) the siblings of individuals with schizophrenia (N = 28); (3) healthy controls (N = 10); and (4) the siblings of healthy controls (N = 17). We examined connectivity within and between four brain networks: (1) frontal-parietal (FP); (2) cingulo-opercular (CO); (3) cerebellar (CER); and (4) default mode (DMN). In terms of within-network connectivity, we found that connectivity within the DMN and FP increased significantly between resting state and 0-back, while connectivity within the CO and CER decreased significantly between resting state and 0-back. Additionally, we found that connectivity within both the DMN and FP was further modulated by memory load. In terms of between network connectivity, we found that the DMN became significantly more "anti-correlated" with the FP, CO, and CER networks during 0-back as compared to rest, and that connectivity between the FP and both CO and CER networks increased with memory load. Individuals with schizophrenia and their siblings showed consistent reductions in connectivity between both the FP and CO networks with the CER network, a finding that was similar in magnitude across rest and all levels of working memory load. These findings are consistent with the hypothesis that altered functional connectivity in schizophrenia reflects a stable characteristic that is present across cognitive states. © 2012 Repovš and Barch.

Znidaric M.,University of Ljubljana
New Journal of Physics | Year: 2010

In this work, we study the transport properties of the anisotropic Heisenberg model in a disordered magnetic field and in the presence of dephasing due to external degrees of freedom. Without dephasing, the model can display, depending on parameter values, the whole range of possible transport regimes: ideal ballistic conduction, diffusive, or ideal insulating behavior. We show that the presence of dephasing induces normal diffusive transport in a wide range of parameters. We also analyze the dependence of spin conductivity on the dephasing strength. In addition, by analyzing the decay of the spin-spin correlation function, we find a long-range order for finite chain sizes. All our results for a one-dimensional spin chain at infinite temperature can be equivalently rephrased for strongly interacting disordered spinless fermions. © IOP Publishing Ltd and Deutsche Physikalische Gesellschaft.

Prosen T.,University of Ljubljana | Zunkovi C B.,University of Ljubljana
New Journal of Physics | Year: 2010

We generalize the method of third quantization to a unified exact treatment of Redfield and Lindblad master equations for open quadratic systems of n fermions in terms of diagonalization of a 4n ×4n matrix. Non-equilibrium thermal driving in terms of the Redfield equation is analyzed in detail. We explain how one can compute all the physically relevant quantities, such as non-equilibrium expectation values of local observables, various entropies or information measures, or time evolution and properties of relaxation. We also discuss how to exactly treat explicitly time-dependent problems. The general formalism is then applied to study a thermally driven open XY spin 1/2 chain. We find that the recently proposed non-equilibrium quantum phase transition in the open XY chain survives the thermal driving within the Redfield model. In particular, the phase of long-range magnetic correlations can be characterized by hypersensitivity of the non-equilibrium steady state to external (bath or bulk) parameters. Studying the heat transport, we find negative differential thermal conductance for sufficiently strong thermal driving as well as non-monotonic dependence of the heat current on the strength of the bath coupling. © IOP Publishing Ltd. and Deutsche Physikalische Gesellschaft.

Mlinar S.,University of Ljubljana
Nursing Ethics | Year: 2010

The aim of this study was to investigate significant differences in the mean scores for the Caring Behaviors Inventory between first-year and third-year nursing students. There were two sample groups: group A comprised 117 first-year nursing students and group B included 49 third-year nursing students (n = 166). All participants were from one Slovenian university. Data were collected by questionnaire and analysed using SPSS v. 17.0. Independent sample t-tests were used for the comparison of means for each item in both groups. The results showed that the students in group B (third year) often agreed more significantly with Caring Behaviors Inventory items than the students in group A (first year). Principles of right action indicate how nurses must behave in order to provide good nursing care. Nursing educators can prepare students through demonstrations of their own behaviour in practice. © The Author(s) 2010.

Gaberscek S.,University of Ljubljana | Zaletel K.,University of Ljubljana
Expert Review of Clinical Immunology | Year: 2011

During pregnancy and after delivery, the maternal thyroid gland faces several metabolic, hemodynamic and immunologic changes. In this article we first summarize the current knowledge on the physiologic adaptation of the healthy thyroid to pregnancy, including variations of thyroid-stimulating hormone and free thyroid hormones, as well as variations of thyroid volume. Our second aim is to illustrate the background of thyroid autoimmunity in this period, which characteristically ameliorates during pregnancy and aggravates after delivery. Although rare during pregnancy, Graves' disease is the most frequent cause of hyperthyroidism, while Hashimoto's thyroiditis is the most frequent cause for hypothyroidism. Both types of thyroid dysfunction may lead to detrimental complications in mother and child and therefore timely recognition and treatment is essential. Postpartum autoimmunity most frequently exacerbates in the form of postpartum thyroiditis, which presents with diverse clinical presentations and may lead to permanent hypothyroidism. © 2011 Expert Reviews Ltd.

Vidrih B.,University of Ljubljana | Medved S.,University of Ljubljana
Urban Forestry and Urban Greening | Year: 2013

This paper presents a study of mitigation of the heat island effect in the built environment with urban (city) parks. The park cooling island (PCI) effect, considering park grass cover and trees' density and age, is determined for selected extreme summer days at various wind speeds under the optimum soil water conditions in the root zone based on an all-day quasi-stationary thermal response. PCI was determined numerically by coupling a CFD model of an urban park and quasi-steady state, two-zone thermal response boundary condition models of each park element. The boundary models are evaluated in form of multi-parameter approximation polynomials taking into account the sensible and latent heat transfer and the geometrical, optical and thermal properties of park elements. Three-dimensional CFD modelling was used for the determination of temperature, humidity and air velocity fields in an urban park with a size of 140. m × 140. m. Based on the comparison of the measured and numerically determined air temperatures in the tree crowns, we proved that the method of linking the models is adequate for temperature and flow condition modelling in the city park environment. The results are presented in the form of local PCI as the difference between local air temperature in the pedestrian zone and the reference air temperature preceding the park. The study proved that it is possible to normalise the cooling effect using the specific dimensionless coefficient of leaf area (LAIsp), which includes an approximation of the density of trees planted in the park and their size or age. It was found out that the cooling effect of the park is up to -4.8°C at LAIsp, equal to 3.16, which corresponds to a planting density of 45 trees per hectare, with an age of 50 years. It was also found that with the length of the park cooling effect change decreases. The optimal length of the park with a LAIsp 3 is 130m. © 2013 Elsevier GmbH.

Prosen T.,University of Ljubljana
Physica Scripta | Year: 2012

In this paper, we provide two extensions of recent explicit results on the matrix-product ansatz for the non-equilibrium steady state of a Markovian boundary-driven anisotropic Heisenberg XXZ spin-1/2 chain. We write a perturbative solution for the steady-state density matrix in the system-bath coupling for an arbitrary (asymmetric) set of four spin-flip rates at the two chain ends, generalizing the symmetric-driving ansatz of Prosen (2011 Phys.Rev.Lett.106217206). Furthermore, we generalize the exact (non-perturbative) form of the steady state for just two Lindblad channels (spin-up flipping on the left and spin-down flipping on the right) to an arbitrary (asymmetric) ratio of the spin-flipping rates (Prosen 2011 Phys.Rev.Lett. 107 137201). In addition, we also indicate a simple proof of the uniqueness of our steady states. © 2012 The Royal Swedish Academy of Sciences.

Prosen T.,University of Ljubljana | Anidaric M.,University of Ljubljana
Physical Review B - Condensed Matter and Materials Physics | Year: 2012

We consider charge and spin transport in the one-dimensional Hubbard model at infinite temperature, half-filling, and zero magnetization. Implementing matrix-product-operator simulations of the nonequilibrium steady states of boundary-driven open Hubbard chains for up to 100 sites we find clear numerical evidence of diffusive transport for weak driving and any (nonzero and finite) value of the interaction U. In addition, nonequilibrium steady states are characterized by nonzero spin-up spin-down density-density correlations. For maximal driving, on the other hand, we find an insulating behavior and cosine-shaped density profiles. © 2012 American Physical Society.

Brozovic M.,University of Ljubljana | Dolsek M.,University of Ljubljana
Earthquake Engineering and Structural Dynamics | Year: 2014

An envelope-based pushover analysis procedure is presented that assumes that the seismic demand for each response parameter is controlled by a predominant system failure mode that may vary according to the ground motion. To be able to simulate the most important system failure modes, several pushover analyses need to be performed, as in a modal pushover analysis procedure, whereas the total seismic demand is determined by enveloping the results associated with each pushover analysis. The demand for the most common system failure mode resulting from the 'first-mode' pushover analysis is obtained by response history analysis for the equivalent 'modal-based' SDOF model, whereas demand for other failure modes is based on the 'failure-based' SDOF models. This makes the envelope-based pushover analysis procedure equivalent to the N2 method provided that it involves only 'first-mode' pushover analysis and response history analysis of the corresponding 'modal-based' SDOF model. It is shown that the accuracy of the approximate 16th, 50th and 84th percentile response expressed in terms of IDA curves does not decrease with the height of the building or with the intensity of ground motion. This is because the estimates of the roof displacement and the maximum storey drift due to individual ground motions were predicted with a sufficient degree of accuracy for almost all the ground motions from the analysed sets. © 2013 John Wiley & Sons, Ltd.

Zalohar J.,University of Ljubljana
Journal of Structural Geology | Year: 2014

Båth's law is one of the three well-known scaling laws for earthquakes. It states that the difference in magnitudes of the mainshock and its largest aftershock is approximately constant, independent of the magnitude of the mainshock. Despite the progress in understanding the nature of Båth's law, the question of whether this law has a physical basis, or is simply a consequence of basic statistical features of aftershock sequences, has remained controversial. In this article we show that Båth's law can be derived within the Cosserat continuum theory from equations describing fault interaction. Our equations can describe both (1) the interacting mainshocks and aftershocks, and (2) the interacting foreshocks and mainshocks. We also derive (1) spatial extension of Båth's law to the normalized distance between the locations of the interacting mainshocks and aftershocks (or foreshocks and mainshocks), and (2) temporal extension of Båth's law to the difference between the time of the interacting mainshocks and aftershocks (or foreshocks and mainshocks). © 2013 Elsevier Ltd.

Mamah D.,Washington University in St. Louis | Barch D.M.,Washington University in St. Louis | Repovs G.,University of Ljubljana
Journal of Affective Disorders | Year: 2013

Background: Bipolar disorder (BPD) and schizophrenia (SCZ) share clinical characteristics and genetic contributions. Functional dysconnectivity across various brain networks has been reported to contribute to the pathophysiology of both SCZ and BPD. However, research examining resting-state neural network dysfunction across multiple networks to understand the relationship between these two disorders is lacking. Methods: We conducted a resting-state functional connectivity fMRI study of 35 BPD and 25 SCZ patients, and 33 controls. Using previously defined regions-of-interest, we computed the mean connectivity within and between five neural networks: default mode (DM), fronto-parietal (FP), cingulo-opercular (CO), cerebellar (CER), and salience (SAL). Repeated measures ANOVAs were used to compare groups, adjusting false discovery rate to control for multiple comparisons. The relationship of connectivity with the SANS/SAPS, vocabulary and matrix reasoning was investigated using hierarchical linear regression analyses. Results: Decreased within-network connectivity was only found for the CO network in BPD. Across groups, connectivity was decreased between CO-CER (p<0.001), to a larger degree in SCZ than in BPD. In SCZ, there was also decreased connectivity in CO-SAL, FP-CO, and FP-CER, while BPD showed decreased CER-SAL connectivity. Disorganization symptoms were predicted by connectivity between CO-CER and CER-SAL. Discussion: Our findings indicate dysfunction in the connections between networks involved in cognitive and emotional processing in the pathophysiology of BPD and SCZ. Both similarities and differences in connectivity were observed across disorders. Further studies are required to investigate relationships of neural networks to more diverse clinical and cognitive domains underlying psychiatric disorders. © 2013 Elsevier B.V.

Znidarsic-Plazl P.,University of Ljubljana
Chimica Oggi/Chemistry Today | Year: 2014

Implementation of biocatalytic reactions in chemical processes is often hampered by poor solubility of organic compounds in water, as well as with low biocatalyst stability and/or near-equilibrium reactions, preventing high final yields. The use of non-aqueous solvents can substantially improve the applicability of biocatalysts for organic synthesis by offering substantially higher substrate and product solubility along with the possibility for in situ product removal in two-liquid phase systems, among others. Miniaturization and continuous-flow processing is gaining importance also in biocatalytic processes, especially when mass transport across phase boundaries is included. This review gives an insight into enzymatic microreactors utilizing either dissolved catalysts within various two-liquid phase systems, or immobilized enzymes employing non-aqueous media, namely ionic liquids and organic solvents. Benefits and drawbacks of parallel and segmented liquid-liquid flows within microfluidic systems, as well as of packed bed mezzo- or microscale reactors utilizing non-aqueous media for biocatalytic reactions are highlighted.

Ilievski E.,University of Ljubljana | Prosen T.,University of Ljubljana
Nuclear Physics B | Year: 2014

We present an explicit construction of a family of steady state density matrices for an open integrable spin-1 chain with bilinear and biquadratic interactions, also known as the Lai-Sutherland model, driven far from equilibrium by means of two oppositely polarizing Markovian dissipation channels localized at the boundary. The steady state solution exhibits n + 1 fold degeneracy, for a chain of length n, due to existence of (strong) Liouvillian U(1) symmetry. The latter can be exploited to introduce a chemical potential and define a grand canonical nonequilibrium steady state ensemble. The matrix product form of the solution entails an infinitely-dimensional representation of a non-trivial Lie algebra (semidirect product of sl2 and a non-nilpotent radical) and hints to a novel Yang-Baxter integrability structure. © 2014 The Authors.

Znidarcic D.,University of Ljubljana | Ban D.,Institute of Agriculture and Tourism Porec | Sircelj H.,University of Ljubljana
Food Chemistry | Year: 2011

Major chloroplast pigments in five leafy vegetables (chicory-Cichorium intybus, cv. 'Anivip' and cv. 'Monivip', dandelion-Taraxacum officinale, garden rocket-Eruca sativa and wild rocket-Diplotaxis tenuifolia), commonly consumed in Mediterranean countries, have been separated by high-performance liquid chromatography (HPLC) on a reversed-phase column. Three classes of pigments were identified and quantified: xanthophylls (oxygenated carotenoids), carotenes (hydrocarbon carotenoids) and chlorophylls. The contents of the pigments in the analysed leafy vegetables varied significantly. The results indicated that selected leafy vegetables were moderately rich in xanthophylls, primarily lutein (3.87-7.44 mg/100 g fwt). Other xanthophylls were detected in relatively small quantities. The provitamin A carotenoids (α- and β-carotene) were also detected, but α-carotene were not present in chicory cultivars and in dandelion. The ratio of chlorophyll a/b varied from 2.44 to 2.67 depending on the species. The highest content of all the analysed constituents was found in the garden rocket. © 2011 Elsevier Ltd. All rights reserved.

Krajnik P.,University of Ljubljana | Drazumeric R.,University of Ljubljana | Badger J.,Grinding Doc Consulting
CIRP Annals - Manufacturing Technology | Year: 2013

This paper introduces two new concepts in peripheral cylindrical grinding of non-round workpieces: (1) choosing process parameters based on a thermal model for achieving a constant temperature; and (2) optimizing the grinding process for shorter cycle times while applying the concept of constant temperature. The modeling of geometry, kinematics and thermal aspects accounts for large variations in specific material-removal rate, contact length and workpiece velocity as the workpiece rotates. Optimization is validated both in simulation and with grinding experiments, including measurements of Barkhausen noise. Significantly reduced cycle times are obtained along with a better ability to avoid thermal damage. © 2013 CIRP.

Cabello S.,University of Ljubljana | Mohar B.,Simon Fraser University | Mohar B.,University of Ljubljana
SIAM Journal on Computing | Year: 2013

A graph is near-planar if it can be obtained from a planar graph by adding an edge. We show the surprising fact that it is NP-hard to compute the crossing number of near-planar graphs. A graph is 1-planar if it has a drawing where every edge is crossed by at most one other edge. We show that it is NP-hard to decide whether a given near-planar graph is 1-planar. The main idea in both reductions is to consider the problem of simultaneously drawing two planar graphs inside a disk, with some of its vertices fixed at the boundary of the disk. This leads to the concept of anchored embedding, which is of independent interest. As an interesting consequence we obtain a new, geometric proof of NP-completeness of the crossing number problem, even when restricted to cubic graphs. This resolves a question of Hliněný. © 2013 Society for Industrial and Applied Mathematics.

Starc G.,University of Ljubljana | Strel J.,University of Ljubljana
BMC Public Health | Year: 2012

Background: This study was constructed as a comparison group pre-test/post-test quasi-experiment to assess the effect of the implementation of the PE curriculum by specialist PE teachers on children's physical development and physical fitness. Methods. 146 classes from 66 Slovenian primary schools were assigned to quasi-test (71) and quasi-control (75) groups. Data from the SLOFIT database was used to compare the differences in physical fitness and development between groups of children whose PE lessons were delivered by specialist PE teachers from the second grade onwards (quasi-test, n = 950) or by generalist teachers in all first three grades (quasi-control, n = 994). The Linear Mixed Model was used to test the influence of specialist PE teachers' teaching. Results: The quasi-control group showed significantly lower improvement of physical fitness by -0.07 z-score units (95% CI -0.12 to 0.02) compared to the quasi-test group. A significant difference of -0.20 (-0.27 to -0.13) was observed in explosive strength, and of -0.15 (-0.23 to -0.08) in running speed, and in flexibility by -0.22 (-0.29 to -0.14). No significant differences in physical development were observed. Conclusions: Specialist PE teachers were more successful than generalist teachers in achieving greater improvement of children's physical fitness, but no differences were observed in physical development of quasi-test and quasi-control group. © 2012Starc and Strel; licensee BioMed Central Ltd.

Slavic J.,University of Ljubljana | Boltezar M.,University of Ljubljana
Mechanical Systems and Signal Processing | Year: 2011

In the past decade damping-identification methods based on the continuous wavelet transform (CWT) have been shown to be some of the best methods for analyzing the damping of multi-degree-of-freedom systems. The CWT methods have proven themselves to be resistant to noise and able to identify damping at closely spaced natural frequencies. However, with the CWT-based techniques, the CWT needs to be obtained on a two-dimensional, timefrequency grid, and they are, therefore, computationally demanding. Furthermore, the CWT is susceptible to the edge effect, which causes a non-valid identification at the start and the end of the time-series. This study introduces a new method, called the Morlet-wave method, where a finite integral similar to the CWT is used for the identification of the viscous damping. Instead of obtaining the CWT on a two-dimensional grid, the finite integral needs to be calculated at one timefrequency point, only. Then using two different integration parameters, the damping ratio can be identified. A complete mathematical background of the new, Morlet-wave, damping-identification method is given and this results in a root-finding or a closed-form solution. The presented numerical experiments show that the new method has a similar performance to the CWT-based damping-identification methods, while the method is numerically, significantly less demanding, completely avoids the edge effect, and the procedure is straightforward to use. © 2010 Elsevier Ltd. All rights reserved.

Volavsek M.,University of Ljubljana
Analytical and Quantitative Cytology and Histology | Year: 2015

Nonsurgical therapeutic options for prostatic diseases are divided into androgen action-related, with androgen action inhibition (AAI), or androgen action-unrelated strategies, such as radiotherapy (RT). AAI, achieved by numerous medications with antiandrogen activity, is used for prostatic hyperplasia and carcinoma. Treatment mostly affects secretory epithelial cells, with consequent reduction in prostate volume and diminished amount of cancer. Histologically, AAI changes the morphologic appearance of benign prostatic glands, prostatic intraepithelial neoplasia, and cancer, as well as prostatic stroma. The effects of most AAI drugs are similar, although variable in intensity. Expression of some diagnostic immunohistochemical markers can decline after longtime treatment, requiring careful interpretation of staining results. Patterns of tissue injury after RT for prostate cancer differ from those after AAI. While irradiation has a profound effect on benign prostatic glands, it does not affect immunohistochemistry, which retains its diagnostic value. In order to make a reliable diagnosis in needle biopsies of treated prostate cancer, uropathologists should have all the relevant information on treatment modalities and their duration. As treatment affects the morphology of prostate cancer, Gleason grading is unreliable and therefore not recommended. An overview of treatment effects caused by AAI and RT is herein presented, with discussion on their importance in everyday practice. © Science Printers and Publishers, Inc.

Simoncic S.,University of Ljubljana | Podrzaj P.,University of Ljubljana
Science and Technology of Welding and Joining | Year: 2014

This paper presents a machine vision based electrode tip displacement measurement. The displacement is obtained by the observation of a certain area (mask) in a sequence of images. Based on the obtained displacement measurement a tip velocity was calculated as well. For this signal Kalman filtering was used in order to reduce noise. The relation between the electrode tip displacement/velocity curve parameters and weld strength was investigated. Among maximum displacement, indentation depth, maximal velocity in cooling phase and maximal velocity in heating phase the latter turned out to be the best parameter for weld strength estimation. © 2014 Institute of Materials, Minerals and Mining.

Orazem P.,University of Ljubljana | Stampar F.,University of Ljubljana | Hudina M.,University of Ljubljana
Food Chemistry | Year: 2011

The fruit quality of 'Redhaven' peach [Prunus persica (L.) Basch] grafted on 11 (Adesoto, Julior, GF 677, Monegro, Barrier 1, Cadaman, MrS 2/5, Ishtara, Penta, Tetra and peach seedling) experimental rootstocks was evaluated in 2008 under replant orchard conditions. Several quality indices [weight, flesh firmness (FF), ground colour measurements, and soluble solids content (SSC)] were measured, and HPLC analysis were performed for numerous chemical parameters (quantification of individual sugars, organic acids, phenolic compounds in skin and in pulp). Total phenolic content and antioxidant capacity in skin and in pulp were also measured. Julior had the heaviest fruit, while Barrier 1 and GF 677 produced fruit lighter in weight. Rootstocks influenced harvest maturity. Monegro produced the least ripe fruit, characterised by high FF, phenolic compounds in the skin and low SSC. Adesoto rootstock resulted in the best overall fruit quality (high values of SSC, individual and total sugar content levels, individual and total organic acids and phenolic compounds in pulp) as well as high total yield. Julior rootstock also produced good quality peach (high values of SSC, individual and total sugars). Cadaman and peach seedling rootstock produced 'Redhaven' fruit of the lowest quality, indicated by low values of sugars, organic acids, phenolic compounds in pulp and in skin. © 2010 Elsevier Ltd.

Trontelj P.,University of Ljubljana | Utevsky S.Y.,University of Kharkiv
Molecular Phylogenetics and Evolution | Year: 2012

Medicinal leeches (Hirudo spp.) are among the best-studied invertebrates in many aspects of their biology. Yet, relatively little is known about their biogeography, ecology and evolution. Previous studies found vast ranges but suggested low genetic diversity for some species. To examine this apparent contradiction, the phylogeny and phylogeography of the widespread Hirudo verbana, Hirudo medicinalis and Hirudo orientalis were investigated in a comparative manner. Populations from across their ranges in Europe, Asia Minor, the Caucasus and Central Asia, were analyzed by various phylogenetic and population genetic approaches using both mitochondrial (COI and 12S) and nuclear DNA sequences (ITS1, 5.8S and ITS2). The populations showed surprisingly little genetic differentiation despite vast ranges. The only clear structure was observed in H. verbana. This species is subdivided into an Eastern (southern Ukraine, North Caucasus, Turkey and Uzbekistan) and a Western phylogroup (Balkans and Italy). The two phylogroups do not overlap, suggesting distinct postglacial colonization from separate refugia. Leeches supplied by commercial facilities belong to the Eastern phylogroup of H. verbana; they originate from Turkey and the Krasnodar Territory in Russia, two leading areas of leech export. H. verbana and H. medicinalis have experienced recent rapid population growth and range expansion, while isolation by distance has shaped the genetic setup of H. orientalis. The habitat of the latter is patchy and scattered about inhospitable arid and alpine areas of Central Asia and Transcaucasia. Centuries of leech collecting and transport across Europe seem not to have affected the natural distribution of genetic diversity, as the observed patterns can be explained by a combination of historical factors and present day climatic influences. © 2012 Elsevier Inc.

The importance of wetting is becoming increasingly obvious and its control is inevitable in many engineering applications, including tribology and interface nanotechnology. However, the relations between the key parameters affecting surface-liquid wetting behaviour under realistic conditions are not very well understood, especially for typical engineering materials and lubricants (oils), often leading to exceptions and contradictions, which impede their use in engineering models and theories, and so the possible optimisation of the interfaces of engineering systems. In this paper we present the correlations between the contact angle, the spreading, the surface tension and the surface energy of fourteen frequently used engineering materials belonging to four different classes of materials (steel, DLC coatings, ceramics, and polymers) wetted with four different liquids: three oils (a non-polar synthetic oil of two different viscosities and a polar natural-based oil) and water. The results represent systematically and consistently obtained data about the wetting-relevant parameters of the selected materials and lubricants and numerous correlations between them. However, the most striking result suggests that the spreading parameter correlates very linearly with the surface energy for all the materials and liquids studied, in both the adhesion-wetting and spreading-wetting regimes. The experimentally determined spreading vs. surface energy correlation functions that appear generally valid for a broad range of properties of the materials and oils can thus be applied as an engineering tool to tailor and design the required/desired wetting performance and nature of the solid-liquid interfaces. The spreading parameter SP - in contrast to the contact angle - was found to be a reliable and relevant parameter for describing the wetting of oils with selected engineering materials. © 2013 Elsevier B.V.

Marolt M.,University of Ljubljana
IEEE Transactions on Audio, Speech and Language Processing | Year: 2012

Bell chiming is a folk music tradition that involves performers playing rhythmic patterns on church bells. The paper presents a method for automatic transcription of bell chiming recordings, where the goal is to detect the bells that were played and their onset times. We first present an algorithm that estimates the number of bells in a recording and their approximate spectra. The algorithm uses a modified version of the intelligent k-means algorithm, as well as some prior knowledge of church bell acoustics to find clusters of partials with synchronous onsets in the time-frequency representation of a recording. Cluster centers are used to initialize non-negative matrix factorization that factorizes the time-frequency representation into a set of basis vectors (bell spectra) and their activations. To transcribe a recording, we propose a probabilistic framework that integrates factorization and onset detection data with prior knowledge of bell chiming performance rules. Both parts of the algorithm are evaluated on a set of bell chiming field recordings. © 2006 IEEE.

In the article, the exact solution of a sinusoidal loaded simply supported rectangular plate is given for the case of an isotropic plate and for the case of a transversally inextensible plate. Asymptotic and numerical comportment with Reissner, Mindlin and Reddy plate models is present. © 2011 Springer Science+Business Media B.V.

Mali B.,University of Ljubljana | Jarm T.,University of Ljubljana | Snoj M.,Institute of Oncology Ljubljana | Sersa G.,Institute of Oncology Ljubljana | Miklavcic D.,University of Ljubljana
European Journal of Surgical Oncology | Year: 2013

Background: This systematic review has two purposes: to consolidate the current knowledge about clinical effectiveness of electrochemotherapy, a highly effective local therapy for cutaneous and subcutaneous tumors; and to investigate the differences in effectiveness of electrochemotherapy with respect to tumor type, chemotherapeutic drug, and route of drug administration. Methods: All necessary steps for a systematic review were applied: formulation of research question, systematic search of literature, study selection and data extraction using independent screening process, assessment of risk of bias, and statistical data analysis using two-sided common statistical methods and meta-analysis. Studies were eligible for the review if they provided data about effectiveness of single-session electrochemotherapy of cutaneous or subcutaneous tumors in various treatment conditions. Results: In total, 44 studies involving 1894 tumors were included in the review. Data analysis confirmed that electrochemotherapy had significantly (p < .001) higher effectiveness (by more than 50%) than bleomycin or cisplatin alone. The effectiveness was significantly higher for intratumoral than for intravenous administration of bleomycin (p < .001 for CR%, p = .028 for OR%). Bleomycin and cisplatin administered intratumorally resulted in equal effectiveness of electrochemotherapy. Electrochemotherapy was more effective in sarcoma than in melanoma or carcinoma tumors. Conclusions: The results of this review shed new light on effectiveness of electrochemotherapy and can be used for prediction of tumor response to electrochemotherapy with respect to various treatment conditions and should be taken into account for further refinement of electrochemotherapy protocols. © 2012 Elsevier Ltd. All rights reserved.

E-learning systems and technologies are playing an increasing role in different educational environments around the world. The acceptance of such technologies is tested with different models that use different criteria. Among them, the Unified Theory of Acceptance and Use of Technology (UTAUT) is one of the more studied theories, but its validity should still be tested in e-learning environments, especially mandatory ones. The purpose of the research was to assess and evaluate the appropriateness of UTAUT within a specific mandatory e-learning environment in higher education and to research the influence of gender and students' previous education on the acceptance and use of such technology. The empirical research, which was based on the theoretical background, included a data collection method using a survey, a data validation method using factor analysis, and structural equation modeling. The results prove the general applicability of the UTAUT model in e-learning settings and demonstrate that social influence and performance expectancy significantly influence the intention to use the technology. Results also prove no significant influence of students' previous education or gender on the model fit. The results suggest that young people think that they handle modern technology well and are ready to use it if only an increase in performance is expected. © 2015 Elsevier Ltd. All rights reserved.

Celarec D.,University of Ljubljana | Dolsek M.,University of Ljubljana
Engineering Structures | Year: 2013

The simplifications in the procedure are associated with a simplified nonlinear method and models for the assessment of the seismic performance of the structure, whereas the effects of the epistemic uncertainty are treated by using the first-order-second-moment (FOSM) method, and the latin hypercube sampling (LHS) technique. The results of sensitivity analysis reveal that it is those parameters which affect the collapse mechanism and have a high coefficient of variation that have the greatest impact on the seismic response parameters for the near collapse limit state. The results of uncertainty analysis by using the LHS technique showed that epistemic uncertainties have an effect on the dispersion, and also on the median estimates of the response parameters. For all three example structures a reduction in the estimate for the median peak ground acceleration at the near-collapse limit state was observed. Thus, explicit consideration of epistemic uncertainties in the process of the assessment of structural performance can lead to more accurate results, and consequently also to more reliable assessment of seismic risk. © 2013 Elsevier Ltd.

Kaljun D.,University of Ljubljana | Zerovnik J.,University of Ljubljana | Zerovnik J.,Institute of Mathematics
Optics Express | Year: 2014

The analytical model [Moreno and Sun, Opt. Express 16, 1808-1819 (2008)] is applied to LED with attached secondary optics. It is shown that a slightly modified model using only three cosine power functions can be used for the cases with symmetric radiation pattern and that good fitting on realistic examples can be achieved with several standard optimization algorithms including local search heuristics and genetic algorithm. © 2014 Optical Society of America.

Svensek D.,University of Ljubljana | Pleiner H.,Max Planck Institute for Polymer Research | Brand H.R.,University of Bayreuth
Physical Review Letters | Year: 2013

We set up a macroscopic model of bacterial growth and transport based on a dynamic preferred direction - the collective velocity of the bacteria. This collective velocity is subject to the isotropic-nematic transition modeling the density-controlled transformation between immotile and motile bacterial states. The choice of the dynamic preferred direction introduces a distinctive coupling of orientational ordering and transport not encountered otherwise. The approach can also be applied to other systems spontaneously switching between individual (disordered) and collective (ordered) behavior and/or collectively responding to density variations, e.g., bird flocks, fish schools, etc. We observe a characteristic and robust stop-and-go behavior. The inclusion of chirality results in a complex pulsating dynamics. © 2013 American Physical Society.

Kroflic A.,University of Ljubljana | Sarac B.,University of Ljubljana | Bester-Rogac M.,University of Ljubljana
Langmuir | Year: 2012

A systematic investigation of the micellization process of a biocompatible zwitterionic surfactant 3-[(3-cholamidopropyl)-dimethylammonium]-1- propanesulfonate (CHAPS) has been carried out by isothermal titration calorimetry (ITC) at temperatures between 278.15 K and 328.15 K in water, aqueous NaCl (0.1, 0.5, and 1 M), and buffer solutions (pH = 3.0, 6.8, and 7.8). The effect of different cations and anions on the micellization of CHAPS surfactant has been also examined in LiCl, CsCl, NaBr, and NaI solutions at 308.15 K. It turned out that the critical micelle concentration, cmc, is only slightly shifted toward lower values in salt solutions, whereas in buffer media it remains similar to its value in water. From the results obtained, it could be assumed that CHAPS behaves as a weakly charged cationic surfactant in salt solutions and as a nonionic surfactant in water and buffer medium. Conventional surfactants alike, CHAPS micellization is endothermic at low and exothermic at high temperatures, but the estimated enthalpy of micellization, ΔH M 0, is considerably lower in comparison with that obtained for ionic surfactants in water and NaCl solutions. The standard Gibbs free energy, ΔGM0, and entropy, ΔSM0, of micellization were estimated by fitting the model equation based on the mass action model to the experimental data. The aggregation numbers of CHAPS surfactant around cmc, obtained by the fitting procedure also, are considerably low (nagg 5 ± 1). Furthermore, some predictions about the hydration of the micelle interior based on the correlation between heat capacity change, Δcp,M 0, and changes in solvent-accessible surface upon micelle formation were made. CHAPS molecules are believed to stay in contact with water upon aggregation, which is somehow similar to the micellization process of short alkyl chain cationic surfactants. © 2012 American Chemical Society.

Vranic A.,University of Ljubljana
Radiology and Oncology | Year: 2010

Meningiomas are intracranial brain tumours that frequently recur. Recurrence rates up to 20% in 20 years for benign meningiomas, up to 80% for atypical meningiomas and up to 100% for malignant meningiomas, have been reported. The most important prognostic factors for meningioma recurrence are meningioma grade, meningioma invasiveness and radicality of neurosurgical resection. The aim of our study was to evaluate the differences in antigenic expression on the surface of meningioma cells between recurrent and non-recurrent meningiomas.Methods. 19 recurrent meningiomas and 35 non-recurrent meningiomas were compared regarding the expression of MIB-1 antigen, progesterone receptors, cathepsin B and cathepsin L, using immunohistochemistry. Results. MIB-1 antigen expression was higher in the recurrent meningioma group (p=0.001). No difference in progesterone receptor status between recurrent and non-recurrent meningiomas was confirmed. Immunohistochemical intensity scores for cathepsin B (p= 0.007) and cathepsin L (p<0.001) were both higher in the recurrent than in the non-recurrent meningioma group.Conslusions. MIB-1 antigen expression is higher in recurrent compared to non-recurrent meningiomas. There is no difference in expression of progesterone receptors between recurrent and non-recurrent meningiomas. Cathepsins B and L are expressed more in recurrent meningiomas.

Mechora S.,University of Ljubljana | Stibilj V.,Jozef Stefan Institute | Germ M.,University of Ljubljana
Aquatic Toxicology | Year: 2013

The uptake of Se(IV) by Myriophyllum spicatum, Ceratophyllum demersum and Potamogeton perfoliatus, and the effects of Se(IV) on their physiological and biochemical characteristics were studied. Plants were cultivated outdoors under semi-controlled conditions in water solution containing Na selenite (20μgSeL-1 and 10mgSeL-1). The higher concentration of Se lowered the photochemical efficiency of PSII in all species studied, while the lower concentration had no effect on any species. The higher concentration of Se lowered respiratory potential in M. spicatum. The response of M. spicatum and C. demersum to Se(IV) regarding chlorophylls was variable, however in the majority of cases, there was a trend of increasing the amount of chlorophylls, while in P. perfoliatus the amount of chlorophyll a decreased. The concentration of Se in plants cultured in 10mgSe(IV)L-1 ranged from 436 to 839μgSeg-1 DM in M. spicatum, 319 to 988μgSeg-1 DM in C. demersum and 310 to 661μgSeg-1 DM in P. perfoliatus. The amount of soluble Se compounds in enzyme extracts of high Se treatment was 27% in M. spicatum, 41% in C. demersum and 35% in P. perfoliatus. Se compounds were determined using HPLC-ICP-MS. It was observed that the applied Se(IV) was mainly transformed to insoluble Se. © 2012 Elsevier B.V.

Background. Light microscopic evaluation of cell morphology in preparations from urine or bladder washing containing exfoliated cells is a standard and primary method for the detection of bladder cancer and also malignancy from other parts of the urinary tract. The cytopathologic examination is a valuable method to detect an early recurrence of malignancy or new primary carcinoma during the follow-up of patients after the treatment of bladder cancer.Conclusions. Characteristic cellular and nuclear signs of malignancy indicate invasive or in situ urothelial carcinoma or high-grade papillary urothelial carcinoma. However, low sensitivity of the method reflects the unreliable cytopathologic diagnosis of low-grade urothelial neoplasms as cellular and nuclear signs of malignancy in these neoplasms are poorly manifested. Many different markers were developed to improve the diagnosis of bladder carcinoma on urinary samples. UroVysion™ test is among the newest and most promising tests. By the method of in situ hybridization one can detect specific cytogenetic changes of urothelial carcinoma.

Kotnik V.,University of Ljubljana
Acta Dermatovenerologica Alpina, Pannonica et Adriatica | Year: 2011

Complement is one of the most important mechanisms of natural resistance preventing infections in humans and animals. It is actively involved in the pathogenesis of several diseases, including skin diseases, characterized by the presence of autoantibodies, foreign microorganisms, altered tissue cells, and the presence of mannan. Complement is intended to kill invading microorganisms but it can also destroy the organism's own damaged or altered cells. It is characterized by vigorous activity and is also potentially harmful for the host if triggered in its own body. This review discusses the significance of complement activation for emerging skin diseases and highlights the importance of serological laboratory tests for the detection of complement system activity alterations in skin diseases such as pemphigus vulgaris, bullous pemphigoid, herpes gestationis, dermatitis herpetiformis, porphyria, urticaria, angioedema, cutaneous vasculitis, systemic lupus erythematosus, partial lipodystrophy, lichen planus, xeroderma pigmentosum, psoriasis, and recurrent cutaneous infections. Finally, we draw attention to the current potential for treating these diseases with complement inhibitors.

Lenarcic Z.,Jozef Stefan Institute | Prelovsek P.,Jozef Stefan Institute | Prelovsek P.,University of Ljubljana
Physical Review Letters | Year: 2012

Nonlinear response of a Mott insulator to external electric field, corresponding to dielectric breakdown phenomenon, is studied within of a one-dimensional half-filled Hubbard model. It is shown that in the limit of nearly spin-polarized insulator the decay rate of the ground state into excited holon-doublon pair can be evaluated numerically as well to high accuracy analytically. Results show that the threshold field depends on the charge gap as F thΔ 3/2. Numerical results on small systems indicate on the persistence of a similar mechanism for the breakdown for decreasing magnetization down to unpolarized system. © 2012 American Physical Society.

Modec B.,University of Ljubljana | Dolenc D.,University of Ljubljana
Inorganic Chemistry Communications | Year: 2012

Molybdenum(V) starting material, (PyH) 5[Mo VOCl 4(H 2O)] 3Cl 2, reacted in acetonitrile with 3-phenyllactic acid (2-hydroxy-3-phenylpropanoic acid) in the presence of tetraphenylphosphonium counterions to {(C 6H 5) 4P} 2[(Mo VIO 2Cl 2) 2(C 2O 4)] (C 2O 4 2- = oxalate anion). By the X-ray structure analysis of the product, the oxidation of the metal to + 6 oxidation state and the oxidative cleavage of 3-phenyllactic acid to oxalate ion were undoubtedly confirmed. Several other products of the transformation of the organic substrate were identified by 1H NMR spectroscopy: phenylacetic acid, benzaldehyde, phenylacetaldehyde and lactone, 3,4-diphenyl-2,5-dihydrofuran-2-one. © 2012 Elsevier B.V.

Prosen T.,University of Ljubljana
Physical Review Letters | Year: 2012

We discuss a combination of unitary and antiunitary symmetry of quantum Liouvillean dynamics, in the context of open quantum systems, which implies a D 2 symmetry of the complex Liouvillean spectrum. For sufficiently weak system-bath coupling, it implies a uniform decay rate for all coherences, i.e., off-diagonal elements of the system's density matrix taken in the eigenbasis of the Hamiltonian. As an example, we discuss symmetrically boundary driven open XXZ spin 1/2 chains. © 2012 American Physical Society.

Vilfan A.,Jozef Stefan Institute | Vilfan A.,University of Ljubljana
Physical Review Letters | Year: 2012

We study the efficiency of self-propelled swimmers at low Reynolds numbers, assuming that the local energetic cost of maintaining a propulsive surface slip velocity is proportional to the square of that velocity. We determine numerically the optimal shape of a swimmer such that the total power is minimal while maintaining the volume and the swimming speed. The resulting shape depends strongly on the allowed maximum curvature. When sufficient curvature is allowed the optimal swimmer exhibits two protrusions along the symmetry axis. The results show that prolate swimmers such as Paramecium have an efficiency that is ∼20% higher than that of a spherical body, whereas some microorganisms have shapes that allow even higher efficiency. © 2012 American Physical Society.

Fajfer S.,Jozef Stefan Institute | Fajfer S.,University of Ljubljana | Kamenik J.F.,Jozef Stefan Institute | Kamenik J.F.,University of Ljubljana | And 2 more authors.
Physical Review Letters | Year: 2012

Present measurements of b→cτν and b→uτν transitions differ from the standard model predictions of lepton flavor universality by almost 4σ. We examine new physics interpretations of this anomaly. An effective field theory analysis shows that minimal flavor violating models are not preferred as an explanation, but are also not yet excluded. Allowing for general flavor violation, right-right vector and right-left scalar quark currents are identified as viable candidates. We discuss explicit examples of two Higgs doublet models, leptoquarks as well as quark and lepton compositeness. Finally, implications for LHC searches and future measurements at the (super-)B factories are presented. © 2012 American Physical Society.

Stojkovic G.,University of Ljubljana | Znidarsic-Plazl P.,University of Ljubljana
Process Biochemistry | Year: 2012

Although whole-cell biocatalysis, as well as microreactor technology, are gaining importance in modern biotechnology, there are just a few literature reports on whole-cell biocatalysis in microreactors. In the present work, a continuously operated microreactor with permeabilized Saccharomyces cerevisiae cells was made out of commercially available plastic tubes and tested as a tool for the development of l-malic acid production accomplished by hydration of fumaric acid. Cells were immobilized on inner walls of microchannels by means of 3-aminopropyltriethoxysilane and glutaraldehyde and further permeabilized in order to enhance mass transfer across the membrane. The effects of different process parameters including medium pH, substrate inlet concentration and flow rate, cell permeabilization conditions, as well as catalyst stability were evaluated and the results compared to previously published data obtained within a bench-scale bioreactor. The presented microfluidic device with immobilized biocatalyst built from low cost and disposable materials could be applied for the fast development of other whole-cell biotransformations. © 2012 Elsevier Ltd.

Mali G.,Slovenian National Institute of Chemistry | Meden A.,University of Ljubljana | Dominko R.,Slovenian National Institute of Chemistry
Chemical Communications | Year: 2010

Polymorphism of Li2MnSiO4 was inspected by 6Li MAS NMR spectroscopy. The detected isotropic shifts and spinning-sideband patterns were successfully reproduced by first-principles calculations and offered an insight into structural differences among the polymorphs. The approach for predicting isotropic shifts was also tested on several other Li-containing paramagnetic structures. © 2010 The Royal Society of Chemistry.

Kralj E.,University of Ljubljana | Podbregar M.,University of Ljubljana | Kejzar N.,University of Ljubljana | Balazic J.,University of Ljubljana
Resuscitation | Year: 2015

Aim of the study: This study aimed to establish the incidence, number and location of CPR-related skeletal chest injuries (SCI) and to investigate the influence of age, gender, changes in resuscitation guidelines and technique of resuscitation. Methods: We analysed SCI in 2148 patients who had undergone resuscitation for non-traumatic cardiac arrest, as shown by autopsies performed at the Institute of Forensic Medicine in Ljubljana in the period 2004-2013. Results: External cardiac massage caused SCI in 86% of males and in 91% of females; sternum fractures occurred in 59% of males and 79% of females, rib fractures in 77% of males and 85% of females and sternocostal separations in 33% of males and 12% of females. The average number of all SCI per person was thus almost the same in males and females: 10.95 vs. 10.96. The percentage of patients injured and the number of SCI increased with age. Changes in resuscitation guidelines were also identified as a factor contributing to the incidence and number of SCI. No adverse effect of the use of LUCAS was found. Conclusion: It is generally considered that at least 1/3 of resuscitated patients sustain rib fractures and at least 1/5 sustains sternum fractures. However, our study showed that these injuries are much more frequent and that increased compression rate and depth cause more SCI. Since in the period 2011-2013 accompanying severe injuries occurred in only 1.85% of cases, the resuscitation technique has not yet jeopardised patient's safety, but further close monitoring is needed. © 2015 The Authors.

Pozar T.,University of Ljubljana
Optics Letters | Year: 2014

An oblique reflection of a laser pulse from a fully reflective mirror is treated using the fundamental nonrelativistic conservation principles of energy and momentum. Since the mirror is considered as an elastic object, the reflection of light gives rise to an elastic wave with measurable amplitude that propagates within the mirror. Our results predict a larger Doppler shift in the reflected pulse for the most common setting, when the mirror is initially at rest, compared to the results obtained when the mirror is treated as rigid. © 2013 Optical Society of America.

Stefane B.,University of Ljubljana | Pozgan F.,University of Ljubljana
Catalysis Reviews - Science and Engineering | Year: 2014

Hydrogenation of prochiral ketones using chiral transition-metal catalysts represents the cleanest way to access enantiomerically enriched secondary alcohols, which are important building blocks in fine chemicals synthesis. Despite excellent activity, selectivity and compatibility of metal complexes with variety of functional groups, no universal catalysts exist. In this article we summarize the advances in catalyst systems for the asymmetric homogenous and heterogenous hydrogenation of ketones that have been made in past decade. The development of catalysts is oriented in reaching as high as activity with low catalyst loadings, using "greener conditions, and ensuring good recyclability of catalysts. Even though ruthenium complexes represent the largest part of the catalysts, other metals rapidly penetrate this field. © 2014 Taylor and Francis Group, LLC.

Kersevan B.P.,University of Ljubljana | Kersevan B.P.,Jozef Stefan Institute | Richter-Was E.,Jagiellonian University
Computer Physics Communications | Year: 2013

The AcerMC Monte Carlo generator is dedicated to the generation of Standard Model background processes which were recognised as critical for the searches at LHC, and generation of which was either unavailable or not straightforward so far. The program itself provides a library of the massive matrix elements (coded by MADGRAPH) and native phase space modules for generation of a set of selected processes. The hard process event can be completed by the initial and the final state radiation, hadronisation and decays through the existing interface with either PYTHIA, HERWIG or ARIADNE event generators and (optionally) TAUOLA and PHOTOS. Interfaces to all these packages are provided in the distribution version. The phase-space generation is based on the multi-channel self-optimising approach using the modified Kajantie-Byckling formalism for phase space construction and further smoothing of the phase space was obtained by using a modified ac-VEGAS algorithm. An additional improvement in the recent versions is the inclusion of the consistent prescription for matching the matrix element calculations with parton showering for a select list of processes. © 2012 Elsevier B.V. All rights reserved.

Pospihalj B.,University of Ljubljana
Analytical and Quantitative Cytology and Histology | Year: 2015

Staging of prostate carcinoma provides a standardized method for tumor classification which is based on involvement of the prostate gland, adjacent local structures, regional lymph nodes, and distant sites. Staging information is therefore crucial for clinicians to be able to assess risk of disease progression, to offer therapeutic choices in the individual patient, and to provide population-based prognostic information. Clinical staging, which is based on data obtained prior to first definitive treatment, relies on tumor determination by digital rectal examination, transrectal ultrasonography, other imaging techniques, and serum PSA level, while pathological staging requires histological identification of tumor extent in prostate gland and surrounding tissues. T1 tumors, denoted to clinically unapparent, not palpable or visible by imaging, are diagnosed by transurethral resection of the prostate procedure or needle biopsy. T2 tumors are confined to the organ, are subdivided by involvement in one or both lobes, and are determined by radical prostatectomy procedure. Stage T3 denotes locally advanced tumors that spread beyond the organ's boundaries, and T4 denotes invasion or fixation to the pelvic organs. Despite wide acceptance of the system as a whole, the current 2010 revision of the American Joint Committee on Cancer/Union for International Cancer Control tumor, node and metastasis (TNM 7) appears to contain some controversies, particularly T2 three-tiered subclassification. This review will cover suggested changes to further TNM editions; these changes have been accumulated in the literature in recent years and include items such as lymph node involvement quantification, "vanishing" carcinoma, Gleason score, resection margin status, pretreatment serum PSA level, as well as difficulties the pathologist may encounter in microscopic examination which may hamper accurate stage assessment. © Science Printers and Publishers, Inc.

Mahnic V.,University of Ljubljana
IEEE Transactions on Education | Year: 2012

In this paper, an undergraduate capstone course in software engineering is described that not only exposes students to agile software development, but also makes it possible to observe the behavior of developers using Scrum for the first time. The course requires students to work as Scrum Teams, responsible for the implementation of a set of user stories defined by a project domain expert playing the role of the Product Owner. During the course, data on project management activities are collected in order to analyze the amount of work completed, compliance with the release and iteration plans, productivity, ability in effort estimation, and the like. The paper discusses the achievement of teaching goals and provides empirical evaluation of students' progress in estimation and planning skills. A summary of lessons learned and recommendations is given, reflecting the issues to be considered when teaching courses in agile software development. Surveys of students have shown that they were overwhelmingly positive about the course, indicating that the course fully met or even exceeded their expectations. © 2011 IEEE.

Jezovnik M.K.,University of Ljubljana | Poredos P.,University of Ljubljana
International Angiology | Year: 2010

Aim. During the past decade, the role of inflammation in the pathophysiology of arterial thrombosis has been elucidated. However, little is known about the relationship between inflammation and venous thrombosis. Recently, inflammation has been accepted as a possible mechanism through which different risk factors trigger thrombus formation in veins. The aim of the present study was to investigate the inflammatory markers and their relationship to idiopathic venous thrombosis. Methods. Fourty-nine patients with first idiopathic venous thrombosis and 48 age matched control subjects were included in the study. Patients were studied 2-4 months after the acute event. Patients and control subjects did not differ in the classical risk factors of atherosclerosis, except in body mass index. In both groups, blood markers of inflammation, namely high sensitive C-reactive protein (hs CRP), interleukins (IL-6, IL-8) and tumour necrosis factor alpha (TNF-α), and circulating markers of endothelial dysfunction/damage namely von Willebrand factor (vWF), P-selectin and the vascular adhesion molecule (VCAM-1) were measured. Results. In comparison to healthy subjects patients had significantly higher levels of inflammatory markers: hs CRP: 2.58 mg/L (1.37-6.61), vs. 1.67 mg/L (0.97-3.24) P=0.044, IL-6: 2.37 pg/mL (1.59-4.10), vs. 2.03 pg/mL (1.45-2.59), P=0.025, IL-8: 3.53 pg/mL (2.94-5.3), vs. 2.25 pg/mL (1.77-2.90) P≤0.0001. However, concentrations of TNF-α did not differ significantly between the groups. Also in patients higher levels of circulating markers of endothelial dysfunction: vWF 150.0 g/L (121.0-195.0) vs. 91.5 g/L (70.5-104.0), P≤0.0001, P-selectin 39.5 pg/L (34.0-40.6) vs. 34.8 pg/L (32.5-38.6) P=0.009. In contrast, levels of VCAM-1 were comparable between the groups. The levels of some inflammatory markers were related to the concentration of von Willebrand factor and P-selectin - IL-6: vWF (r=0.36, P=0.08), hs CRP: P-selectin (r=0.44, P=0.018), IL-6: P-selectin (r=0.51, P=0.0002), IL-8: P-selectin (r=0.38, P=0.043). Conclusion. Patients with idiopathic venous thrombosis have increased levels of circulating markers of inflammation and blood markers of endothelial dysfunction. Higher levels of both groups of markers indicate that patients in the stable phase of the disease have an increased systemic inflammatory response. The interrelationship between inflammatory markers and markers of endothelial dysfunction favour the hypothesis that inflammation could be involved in the etiopathogenesis of idiopathic venous thrombosis.

Zabkar V.,University of Ljubljana | Hosta M.,University of Ljubljana
International Journal of Consumer Studies | Year: 2013

Green marketing has not shown expected results in recent years in terms of real changes in behaviours, products and market structures as had been anticipated. Consumer behaviour plays an important role in making these changes happen, and drivers of environmentally conscious consumer behaviour still need to be examined. Concepts of 'concern', 'information about environmental impact' and 'willingness to act' are seen as the key predictors of environmentally conscious consumer behaviours. Although green marketing has been able to address genuinely concerned consumers, additional insights are needed regarding how to appeal to more mainstream consumers. Thus, this paper proposes an extended model of environmentally conscious consumer behaviour in which the gap between willingness to act and actual environmentally friendly consumption is addressed by the moderating role of 'prosocial status' perceptions. In the model, 'concern' is positively related to 'willingness' and both 'willingness' and 'information' are positively related to 'behaviour', while 'prosocial status' perceptions moderate 'behaviour'. The model was verified using a quota sample of 319 general population respondents from a Central European country. According to data, 'prosocial status' perceptions increase the positive association between 'willingness' and 'behaviour' and could be incorporated into green products and advertising to signal personality traits like kindness and intelligence. One possible implication for marketers is that women have a higher average representation in groups of people with high prosocial status perceptions. © 2012 Blackwell Publishing Ltd.

Niciforovic N.,University of Ljubljana | Abramovic H.,University of Ljubljana
Comprehensive Reviews in Food Science and Food Safety | Year: 2014

Sinapic acid is widespread in the plant kingdom (fruits, vegetables, cereal grains, oilseed crops, and some spices and medicinal plants) and as such is common in the human diet. Derivatives of sinapic acid are characteristic compounds in the Brassicaceae family. Sinapic acid shows antioxidant, antimicrobial, anti-inflammatory, anticancer, and anti-anxiety activity. 4-Vinylsyringol (a decarboxylation product of sinapic acid) is a potent antioxidative and antimutagenic agent which suppresses carcinogenesis and the induction of inflammatory cytokines. Sinapine (sinapoyl choline) is considered to be an acetylcholinesterase inhibitor which might have therapeutic applications in various disease treatments. Mainly due to their antioxidative activity, these compounds have been suggested for potential use in food processing, cosmetics, and the pharmaceutical industry, and this review aims to summarize current knowledge on the natural sources, chemistry, and biological activity of these substances. © 2013 Institute of Food Technologists®.

Lang C.B.,University of Graz | Mohler D.,Fermi National Accelerator Laboratory | Prelovsek S.,University of Ljubljana | Prelovsek S.,Jozef Stefan Institute | Woloshyn R.M.,TRIUMF Laboratory Particle and Nuclear Physics
Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics | Year: 2015

We determine the spectrum of Bs 1P states using lattice QCD. For the Bs1(5830) and Bs2*(5840) mesons, the results are in good agreement with the experimental values. Two further mesons are expected in the quantum channels JP=0+ and 1+ near the BK and B*K thresholds. A combination of quark-antiquark and B(*) meson-Kaon interpolating fields are used to determine the mass of two QCD bound states below the B(*)K threshold, with the assumption that mixing with Bs(*)η and isospin-violating decays to Bs(*)π are negligible. We predict a JP=0+ bound state Bs0 with mass mBs0=5.711(13)(19) GeV. With further assumptions motivated theoretically by the heavy quark limit, a bound state with mBs1=5.750(17)(19) GeV is predicted in the JP=1+ channel. The results from our first principles calculation are compared to previous model-based estimates. © 2015 The Authors.

Stanek G.,Medical University of Vienna | Wormser G.P.,New York Medical College | Gray J.,University College Dublin | Strle F.,University of Ljubljana
The Lancet | Year: 2012

Lyme borreliosis (Lyme disease) is caused by spirochaetes of the Borrelia burgdorferi sensu lato species complex, which are transmitted by ticks. The most common clinical manifestation is erythema migrans, which eventually resolves, even without antibiotic treatment. However, the infecting pathogen can spread to other tissues and organs, causing more severe manifestations that can involve a patient's skin, nervous system, joints, or heart. The incidence of this disease is increasing in many countries. Laboratory evidence of infection, mainly serology, is essential for diagnosis, except in the case of typical erythema migrans. Diagnosed cases are usually treated with antibiotics for 2-4 weeks and most patients make an uneventful recovery. No convincing evidence exists to support the use of antibiotics for longer than 4 weeks, or for the persistence of spirochaetes in adequately treated patients. Prevention is mainly accomplished by protecting against tick bites. There is no vaccine available for human beings. © 2012 Elsevier Ltd.

Ausec L.,University of Ljubljana | van Elsas J.D.,University of Groningen | Mandic-Mulec I.,University of Ljubljana
Soil Biology and Biochemistry | Year: 2011

Laccases of fungal origin have been intensively studied due to their importance in various biotechnological applications. There is a constant demand for new laccases with improved properties such as stability at higher temperatures or at an alkaline pH. Growing molecular evidence suggests that laccases may also be widespread in bacteria. While only a handful of bacterial laccases have been purified and characterized, several novel traits have already been discovered (e.g. pH-stability and 2-domain organization of the enzyme as opposed to the usual 3-domain structure of fungal laccases). The aim of this study was to examine the diversity of bacterial laccase-like genes in two types of high-organic peat soil using a cloning and sequencing approach. Gene libraries prepared of small fragments (150 base pairs) revealed an amazing diversity of bacterial laccases. The fragments clustered in 11 major lineages, and one third of the 241 sequences resembled laccase-like genes of Acidobacteria. Additionally, a new primer was used to retrieve several larger fragments of the putative bacterial laccase genes that spanned all four copper-binding sites. Both "conventional" 3-domain laccases and the recently described 2-domain small laccases have been obtained using this approach, demonstrating the potential of the primer. The present study thus contributes to the understanding of the diversity of bacterial laccases and provides a new tool for finding laccase-like sequences in bacterial strains and soil samples. © 2011 Elsevier Ltd.

Dovrtel K.,University of Ljubljana | Medved S.,University of Ljubljana
Applied Energy | Year: 2011

In this paper, the optimization of a weather-predicted free cooling system combined with heat storage is shown. The method of incorporating weather forecasts into the control system is presented. The regime of operation was selected and optimized based on free cooling energy and the required temperature parameters of a building's indoor environment, using variable flow rate control through the heat storage. The savings achieved by optimal operation compared to steady state operation were analyzed. The parametric analysis of optimal system operation was done for different outdoor and indoor environment parameters and for different heat storage construction parameters. The results showed a significant influence of system operation control on system performance. © 2011 Elsevier Ltd.

Kavcic P.,University of Ljubljana
Croatian medical journal | Year: 2011

To examine the effect of acute sleep deprivation under light conditions on the expression of two key clock genes, hPer2 and hBmal1, in peripheral blood mononuclear cells (PBMC) and on plasma melatonin and cortisol levels. Blood samples were drawn from 6 healthy individuals at 4-hour intervals for three consecutive nights, including a night of total sleep deprivation (second night). The study was conducted in April-June 2006 at the University Medical Centre Ljubljana. We found a significant diurnal variation in hPer2 and hBmal1 expression levels under baseline (P<0.001, F=19.7, df=30 for hPer2 and P<0.001, F=17.6, df=30 for hBmal1) and sleep-deprived conditions (P<0.001, F=9.2, df=30 for hPer2 and P<0.001, F=13.2, df=30 for hBmal1). Statistical analysis with the single cosinor method revealed circadian variation of hPer2 under baseline and of hBmal1 under baseline and sleep-deprived conditions. The peak expression of hPer2 was at 13:55 ± 1:15 hours under baseline conditions and of hBmal1 at 16:08 ± 1:18 hours under baseline and at 17:13 ± 1:35 hours under sleep-deprived conditions. Individual cosinor analysis of hPer2 revealed a loss of circadian rhythm in 3 participants and a phase shift in 2 participants under sleep-deprived conditions. The plasma melatonin and cortisol rhythms confirmed a conventional alignment of the central circadian pacemaker to the habitual sleep/wake schedule. Our results suggest that 40-hour acute sleep deprivation under light conditions may affect the expression of hPer2 in PBMCs..

Majdandzic A.,Boston University | Podobnik B.,Boston University | Podobnik B.,University of Rijeka | Podobnik B.,University of Ljubljana | And 5 more authors.
Nature Physics | Year: 2013

Much research has been carried out to explore the structural properties1-10 and vulnerability11-19 of complex networks. Of particular interest are abrupt dynamic events that cause networks to irreversibly fail13-17. However, in many real-world phenomena, such as brain seizures in neuroscience or sudden market crashes in finance, after an inactive period of time a significant part of the damaged network is capable of spontaneously becoming active again. The process often occurs repeatedly. To model this marked network recovery, we examine the effect of local node recoveries and stochastic contiguous spreading, and find that they can lead to the spontaneous emergence of macroscopic 'phase-flipping' phenomena. As the network is of finite size and is stochastic, the fraction of active nodes z switches back and forth between the two network collective modes characterized by high network activity and low network activity. Furthermore, the system exhibits a strong hysteresis behaviour analogous to phase transitions near a critical point. We present real-world network data exhibiting phase switching behaviour in accord with the predictions of the model. © 2014 Macmillan Publishers Limited. All rights reserved.

Rudez U.,University of Ljubljana | Mihalic R.,University of Ljubljana
Electric Power Systems Research | Year: 2011

The research and development of underfrequency load-shedding protection tends to rely on an adaptive approach. Unfortunately, adaptive schemes are very dependent on an active power imbalance determination, based on a measurement of the frequency first derivative. Therefore, their effectiveness might be seriously reduced by a lack of data or the wrong estimation of certain parameters that are needed to accurately define the relation between the frequency first derivative and the active power imbalance. Consequently, it is reasonable to attempt to avoid having to calculate the imbalance. A novel approach to underfrequency load shedding is presented in this paper, using the frequency second derivative as a source of information for a forecast of the frequency trajectory. A Newton-method-based approximation and the interpolation of the frequency second derivative are continuously performed in order to forecast the minimum frequency value using a numerical integration. © 2010 Elsevier B.V. All rights reserved.

Kanduser M.,Infrastructural Center | Usaj M.,University of Ljubljana
Expert Opinion on Drug Delivery | Year: 2014

Introduction: In the past few decades, new methods for drug and gene delivery have been developed, among which electroporation and electrofusion have gained noticeable attention. Lately, advances in the field of immunotherapy have enabled new cancer therapies based on immune response, including monoclonal antibodies and cell vaccines. Efficient cell fusion is needed for both hybridoma production and cell vaccine preparation, and electrofusion is a promising method to achieve this goal. Areas covered: In the present review, we cover new strategies of cancer treatment related to antibody production and cell vaccines. In more detail, cell electroporation and electrofusion are addressed. We briefly describe principles of cell electroporation and focus on electrofusion and its influential factors, with special attention on the fusogenic state of the cell membrane, contact formation, the effect of electrofusion media and cell viability. We end the review with an overview of the very promising field of microfluidic devices for electrofusion. Expert opinion: In our opinion, electrofusion can be a very efficient method for hybridoma and cell vaccine production. Advances in the development of microfluidic devices and a better understanding of the underlying (biological) mechanisms will overcome the current limitations. © 2014 Informa UK, Ltd.

Phillip M.,Jesse Z And Sara Lea Shafer Institute For Endocrinology And Diabetes | Phillip M.,Tel Aviv University | Battelino T.,University of Ljubljana | Atlas E.,Jesse Z And Sara Lea Shafer Institute For Endocrinology And Diabetes | And 8 more authors.
New England Journal of Medicine | Year: 2013

BACKGROUND: Recent studies have shown that an artificial-pancreas system can improve glucose control and reduce nocturnal hypoglycemia. However, it is not known whether such results can be replicated in settings outside the hospital. METHODS: In this multicenter, multinational, randomized, crossover trial, we assessed the short-term safety and efficacy of an artificial pancreas system for control of nocturnal glucose levels in patients (10 to 18 years of age) with type 1 diabetes at a diabetes camp. In two consecutive overnight sessions, we randomly assigned 56 patients to receive treatment with an artificial pancreas on the first night and a sensor-augmented insulin pump (control) on the second night or to the reverse order of therapies on the first and second nights. Thus, all the patients received each treatment in a randomly assigned order. The primary end points were the number of hypoglycemic events (defined as a sensor glucose value of <63 mg per deciliter [3.5 mmol per liter] for at least 10 consecutive minutes), the time spent with glucose levels below 60 mg per deciliter (3.3 mmol per liter), and the mean overnight glucose level for individual patients. RESULTS: On nights when the artificial pancreas was used, versus nights when the sensor-augmented insulin pump was used, there were significantly fewer episodes of nighttime glucose levels below 63 mg per deciliter (7 vs. 22) and significantly shorter periods when glucose levels were below 60 mg per deciliter (P=0.003 and P=0.02, respectively, after adjustment for multiplicity). Median values for the individual mean overnight glucose levels were 126.4 mg per deciliter (interquartile range, 115.7 to 139.1 [7.0 mmol per liter; interquartile range, 6.4 to 7.7]) with the artificial pancreas and 140.4 mg per deciliter (interquartile range, 105.7 to 167.4 [7.8 mmol per liter; interquartile range, 5.9 to 9.3]) with the sensor-augmented pump. No serious adverse events were reported. CONCLUSIONS: Patients at a diabetes camp who were treated with an artificial-pancreas system had less nocturnal hypoglycemia and tighter glucose control than when they were treated with a sensor-augmented insulin pump. (Funded by Sanofi and others; ClinicalTrials.gov number, NCT01238406.) Copyright © 2013 Massachusetts Medical Society.

Levart T.K.,University of Ljubljana
Croatian Medical Journal | Year: 2013

We describe a case of a post vaccine immune complex-mediated glomerulonephritis in an infant with compound heterozygous mutations of C2 complement component gene, which is the first such case in the literature. The three and a half months old boy presented with clinical and laboratory signs of nephritic syndrome and was successfully treated with methylprednisolone. An explanation of such a clinical picture may lie in the interaction between C2 deficiency and vaccination.

Zitnik M.,University of Ljubljana | Zupan B.,University of Ljubljana | Zupan B.,Baylor College of Medicine
IEEE Transactions on Pattern Analysis and Machine Intelligence | Year: 2015

For most problems in science and engineering we can obtain data sets that describe the observed system from various perspectives and record the behavior of its individual components. Heterogeneous data sets can be collectively mined by data fusion. Fusion can focus on a specific target relation and exploit directly associated data together with contextual data and data about system's constraints. In the paper we describe a data fusion approach with penalized matrix tri-factorization (DFMF) that simultaneously factorizes data matrices to reveal hidden associations. The approach can directly consider any data that can be expressed in a matrix, including those from feature-based representations, ontologies, associations and networks. We demonstrate the utility of DFMF for gene function prediction task with eleven different data sources and for prediction of pharmacologic actions by fusing six data sources. Our data fusion algorithm compares favorably to alternative data integration approaches and achieves higher accuracy than can be obtained from any single data source alone. © 2014 IEEE.

Podgornik B.,Slovenian Institute of Metals And Technology | Jerina J.,University of Ljubljana
Surface and Coatings Technology | Year: 2012

Tribological evaluation of the tool steel, focused on determining coefficient of friction and critical load for galling initiation against austenitic stainless steel as a function of surface topography was carried out in a load-scanning test rig. Surfaces investigated included turned, ground, polished, shot penned and laser surface textured cold work tool steel. Additionally, effect of surface roughness and post-polishing on galling resistance of TiN and DLC coated surfaces was investigated. Results of this investigation show that by removing sharp peaks polishing of the bearing surface gives plateau-like topography and improves galling properties of forming tool steel. This becomes even more important when using hard ceramic coatings (i.e. TiN). When superbly polished contact surfaces can give similar galling resistance as otherwise obtained through contact lubrication. However, application of low friction coatings or introduction of micro-dimples with proper density and contact lubrication will result in superior galling resistance of the surface. © 2011 Elsevier B.V.

Virant-Klun I.,University of Ljubljana
Stem Cells and Cloning: Advances and Applications | Year: 2015

In spite of generally accepted dogma that the total number of follicles and oocytes is established in human ovaries during the fetal period of life rather than forming de novo in adult ovaries, some new evidence in the field challenges this understanding. Several studies have shown that different populations of stem cells, such as germinal stem cells and small round stem cells with diameters of 2 to 4 μm, that resembled very small embryonic-like stem cells and expressed several genes related to primordial germ cells, pluripotency, and germinal lineage are present in adult human ovaries and originate in ovarian surface epithelium. These small stem cells were pushed into the germinal direction of development and formed primitive oocyte-like cells in vitro. Moreover, oocyte-like cells were also formed in vitro from embryonic stem cells and induced pluripotent stem cells. This indicates that postnatal oogenesis is not excluded. It is further supported by the occurrence of mesenchymal stem cells that can restore the function of sterilized ovaries and lead to the formation of new follicles and oocytes in animal models. Both oogenesis in vitro and transplantation of stem cell-derived “oocytes” into the ovarian niche to direct their natural maturation represent a big challenge for reproductive biomedicine in the treatment of female infertility in the future and needs to be explored and interpreted with caution, but it is still very important for clinical practice in the field of reproductive medicine. © 2015 Virant-Klun.

Rejc M.,University of Ljubljana | Pantos M.,University of Ljubljana
IEEE Transactions on Power Systems | Year: 2011

In a deregulated environment, system operators are required to procure certain ancillary services, which, among others, may include compensation for active-power losses. This compensation usually involves long-term energy purchases and additional short-term energy purchases to cover the daily fluctuations. The short-term energy purchases require an accurate and quick short-term forecasting method that has to be efficiently applicable in day-ahead markets. This paper presents a novel short-term active-power-loss forecast method using power-flow analysis for the forecasted day. Specifically, this includes short-term load and generation forecasts as well as network-topology forecasts, which are used for the power-flow calculations and the resulting active-power loss calculations. To minimize the forecast errors, a fuzzy-weight grouping of the different short-term load and generation forecast results is proposed. An additional step for input-data pre-processing is presented, where the fuzzy clustering considers the patterns for training the forecasting models. The proposed approach was verified by using real data for the ENTSO-E interconnection and tested for the Slovenian power system. The forecasting results demonstrate the improved accuracy of the proposed approach. © 2011 IEEE.

Rudez U.,University of Ljubljana | Mihalic R.,University of Ljubljana
IEEE Transactions on Power Systems | Year: 2011

The actual activation of underfrequency load shedding is rarely needed in a power system. However, this does not diminish its significance, as it is the last barrier before a system blackout if underfrequency conditions occur. Like in all other areas of application, a tendency also exists to maximize the efficiency of the underfrequency load-shedding scheme and to bring its operation to the limits. By default, the scheme should be able to stop a frequency fall under any circumstances. However, trying to lower the quantity of the disconnected load in the same process is the purpose of this paper. After the theoretical background is summarized, in terms of the reaction of individual generators in the islanded system to a certain power imbalance, a procedure is described showing how it is possible to adjust any of the adaptive load-shedding schemes to utilize as much primary frequency control as possible. As a reference, a theoretically optimal underfrequency load-shedding scheme is presented. © 2010 IEEE.

Rudez U.,University of Ljubljana | Mihalic R.,University of Ljubljana
IEEE Transactions on Power Delivery | Year: 2011

Underfrequency load shedding is one of the most important protection systems, as in many cases it represents the last chance to prevent a system blackout after a serious disturbance occurs in a power system. In order to improve traditional schemes, many efforts have been concentrated on attempts to use the frequency gradient as an indicator for determining the lack of active power in a system. This paper concentrates on analyzing the factors that influence the gradient. Analyses have shown that the gradient can give misleading information about the active-power deficit, as long as certain factors are ignored or assumed to be constant. A draft of a gradient-based underfrequency load-shedding scheme is presented, which also highlights the problems associated with the use of gradient. On the one hand, a frequency gradient alone does not appear to be sufficient for the active-power deficit estimation. Nevertheless, for the actual load-shedding procedure it is found to be very useful. © 2010 IEEE.

Vinkovic A.,University of Ljubljana | Mihalic R.,University of Ljubljana
International Journal of Electrical Power and Energy Systems | Year: 2011

In this paper a universal approach to the modeling of the 2nd generation FACTS devices for power-flow calculations by applying the Newton-Raphson method for current-based models is discussed. First, the basic principles of modeling 2nd generation FACTS devices using current-based models and the current-based models themselves are presented. This is followed by a discussion about the universality of the proposed model. Next, a definition of the FACTS devices' free parameters, a mathematical description of their type, the problem of the initial conditions and the handling of constraints are discussed. The derived model was then tested on the IEEE 57, IEEE 118 and IEEE 300 bus systems. Finally, the main achievements are summarized. © 2011 Elsevier Ltd. All rights reserved.

Aim: The aim of the present study was to test the association between genetic polymorphisms with functional effects on redox regulation: the -262C/T of the catalase gene promoter (rs1001179), the C242T of the nicotinamide adenine dinucleotide phosphate (NADPH) oxidase P22phox gene (rs4673), and the 594C/T polymorphism of the glutathione peroxidase gene (rs1050450) and arterial hypertension (AH) in patients with type 2 diabetes. Methods: 810 Slovenian subjects (Caucasians) with type 2 diabetes were enrolled in the cross-sectional study. Genotypes were determined by real-time PCR. Results: Univariate analysis failed to demonstrate an association between either the -262C/T of the catalase gene promoter (rs1001179) or the C242T polymorphism of the P22phox gene (rs4673) or the 594C/T polymorphism of the glutathione peroxidase gene (rs1050450) and AH. After adjustment for age, body mass index, fibrinogen level and high sensitivity C-reactive protein level, rs4673 was found to be an independent risk factor for AH in subjects with type 2 diabetes, whereas rs1001179 and rs1050450 were not. Conclusion: According to the results of cross-sectional study, the tested polymorphism of the NADPH oxidase P22phox gene (rs4673) was found to be associated with the development of AH, indicating that the oxidative stress gene NADPH oxidase might be implicated in the pathogenesis of AH in subjects with type 2 diabetes. © 2014 Informa Healthcare USA, Inc.

Vodusek D.B.,University of Ljubljana
European Neurology | Year: 2014

Background: Lower urinary tract dysfunction (LUTD) and sexual dysfunction (SD) are common in neurological patients due to a combination of lesions affecting relevant neural control, constraints imposed by sensorimotor and cognitive deficits and - particularly for SD - psychosocial consequences of chronic neurological disease. Summary: This review summarizes the etiology, diagnosis and treatment of LUTD and SD in neurological patients. Key Messages: LUTD may lead to serious health problems; both LUTD and SD significantly affect quality of life. Management of patients with spinal cord injury and dysraphism is undertaken in specialized centers according to established guidelines. Treatment of neurological patients with noncomplicated neurogenic LUTD or SD should preferentially be guided by a neurologist. Clinical Impact: For rational treatment of urinary symptoms, an accurate assessment is mandatory; the bladder and the sphincter need to be defined as normal, over- or underactive. Urodynamic testing is the gold standard for functional diagnosis; assessment of residual urine and uroflow are the minimal requirements before considering management. Dysfunction of desire, arousal and orgasm (ejaculation) may be diagnosed by medical history and are amenable to counselling and treatment, which is - in the case of erectile dysfunction - evidence based. Further high-quality studies are necessary to test the best approaches for diagnosing and managing particular types of neurogenic LUTD and SD in the different neurological patient populations. © 2014 S. Karger AG, Basel.

Gilbert R.J.C.,University of Oxford | Serra M.D.,Fondazione Bruno Kessler | Froelich C.J.,University of Chicago | Wallace M.I.,University of Oxford | And 2 more authors.
Trends in Biochemical Sciences | Year: 2014

Pore-forming proteins (PFPs) interact with lipid bilayers to compromise membrane integrity. Many PFPs function by inserting a ring of oligomerized subunits into the bilayer to form a protein-lined hydrophilic channel. However, mounting evidence suggests that PFPs can also generate 'proteolipidic' pores by contributing to the fusion of inner and outer bilayer leaflets to form a toroidal structure. We discuss here toroidal pore formation by peptides including melittin, protegrin, and Alzheimer's Aβ1-41, as well as by PFPs from several evolutionarily unrelated families: the colicin/Bcl-2 grouping including the pro-apoptotic protein Bax, actinoporins derived from sea anemones, and the membrane attack complex-perforin/cholesterol dependent cytolysin (MACPF/CDC) set of proteins. We also explore how the structure and biological role of toroidal pores might be investigated further. © 2014 Elsevier Ltd.

Bokalic M.,University of Ljubljana | Krasovec U.O.,University of Ljubljana | Topic M.,University of Ljubljana
Progress in Photovoltaics: Research and Applications | Year: 2013

In this study, electroluminescence as a spatial characterisation technique is used to characterise a 6.9% efficient dye-sensitised solar cell. The obtained image is compared with a light beam-induced current scan image and a transmittance image. Results reveal the presence of inhomogeneities including those resulting from the topography of the cell and from defects, for example, presence of iodine crystals in the electrolyte, localised absence of dye in the active layer and poor adhesion of the active layer to the electrodes. The ability to identify such inhomogeneities within a relatively short acquisition time gives electroluminescence an advantage over the light beam-induced current technique. Copyright © 2012 John Wiley & Sons, Ltd. Increasing silver prices and reducing silicon wafer thicknesses provide incentives for silicon solar cell manufacturing to develop new metallization strategies that do not rely on screen printing and reduce silver usage. Recently, metal plating has re-emerged as a metallization process that may address these future requirements. This paper reports on the evolution of metal-plating techniques, from their use in early silicon solar cells to current light-induced plating processes. Copyright © 2012 John Wiley & Sons, Ltd.

Drobnak J.,Jozef Stefan Institute | Fajfer S.,Jozef Stefan Institute | Fajfer S.,University of Ljubljana | Kamenik J.F.,Jozef Stefan Institute
Physical Review Letters | Year: 2010

We compute the branching ratios for the rare top quark decays t→cγ and t→cZ mediated by effective flavor changing neutral couplings at next-to-leading order in QCD, including the effects due to operator mixing. After resumming contributions of the order of [αslog(Λ/mt) ]n, where Λ is the scale at which the effective operators are generated, using renormalization group methods, we compute finite matrix element corrections and study the effects of experimental kinematic cuts on the extracted branching ratios. We find that the t→cγ decay can also be used to probe the effective operators mediating t→cg processes, since the latter can naturally contribute 10% or more to the radiative decay. Conversely, any experimental signal of t→cg would indicate a natural lower bound on t→cZ, γ. © 2010 The American Physical Society.

Mierzejewski M.,Jozef Stefan Institute | Mierzejewski M.,University of Silesia | Prelovsek P.,Jozef Stefan Institute | Prelovsek P.,University of Ljubljana
Physical Review Letters | Year: 2010

Nonlinear real-time response of interacting particles is studied on the example of a one-dimensional tight-binding model of spinless fermions driven by electric field. Using equations of motion and numerical methods we show that for a nonintegrable case at finite temperatures the major effect of nonlinearity can be taken into account within the linear response formalism extended by a renormalization of the kinetic energy due to the Joule heating. On the other hand, integrable systems show on constant driving a different universality with a damped oscillating current whereby the frequency is related but not equal to the Bloch oscillations. © 2010 The American Physical Society.

Zelnik I.,University of Ljubljana
Biodiversity and Conservation | Year: 2013

Relationships between environmental factors and plant species-richness as well as the composition of plant species in wet grasslands from the order Molinietalia caeruleae were studied with a view to quantifying the relative contribution of different abiotic factors, such as soil chemical parameters, climatic conditions and human impact to diversity of vascular plants and floristic composition. Data and soil samples were collected from 88 plots across Slovenia from regions at the eastern edge of the Po plain, karstic and pre-Alpine mountain regions and the western part of the Pannonian plain, which are classified to sub-Mediterranean, Dinnaric, pre-Alpine and sub-Pannonian phytogeographic areas. Plant diversity was positively correlated with the content of exchangeable Ca2+ in soil and the amount of annual precipitation, while significant negative correlation was calculated in case of the plant-available phosphorous content and altitude. Moreover, plant species richness was also negatively correlated with altitude. Among the groups of environmental factors the group of soil factors revealed the strongest correlation with species richness, followed by climatic and topographic group. The order of these groups was the same in the explanation of species composition. Variance of plant species composition was best explained with altitude, soil pH, geographical gradient, frequency of flooding, mean annual temperature, date of mowing, humidity, annual amount of precipitation as well as with the content of plant-available phosphorous, total nitrogen, exchangeable Mg2+ and Ca2+ in the soil. © 2013 Springer Science+Business Media Dordrecht.

Oblak S.,University of Ljubljana | Skrjanc I.,University of Ljubljana
Chemical Engineering Science | Year: 2010

This paper deals with a novel formulation of continuous-time model-predictive control for nonlinear systems. A nonlinear-mapping approximation, employing a PWL approximation, is also an integral part of the control scheme, and thus removes the need for output-function invertibility. The analytical formulation of the control law makes it possible to use the method in practice, especially in the chemical industry. An illustrative experiment is conducted to compare the proposed approach with the method of nonlinear H ∞ control of a pH-neutralization process. © 2009 Elsevier Ltd. All rights reserved.

Krofel M.,University of Ljubljana | Kos I.,University of Ljubljana | Jerina K.,University of Ljubljana
Behavioral Ecology and Sociobiology | Year: 2012

Scavenging is an important but poorly understood ecological process. Dominant scavengers can impose a selection pressure that alters the predator's fitness, morphology, behavior, and ecology. Interactions between ursids, likely the most important dominant scavengers in the Holarctic region, and solitary felids, which are characterized by long feeding times, provide a good opportunity for studying the effects of kleptoparasitism by dominant scavengers. We analyzed the effects of scavenging by brown bears Ursus arctos on Eurasian lynx Lynx lynx and predator's response to kleptoparasitism in a European temperate forest ecosystem. Bears found 32 % of lynx prey remains and 15 % of all biomass of large prey killed by lynx was lost to bears. In response, lynx increased their kill rate by 23 % but were able to compensate for only 59 % of the losses. The frequency of bear scavenging was strongly dependent on bear activity patterns and was highest during the lynx pregnancy and lactation period, when up to half of lynx kills were usurped by bears. We suggest that ursid scavenging, by promoting the hunting of smaller prey, may have played an important role in the evolution of the Lynx genus as well as other predators in the Holarctic. Our study indicates that prey loss to dominant scavengers is a widespread phenomenon among felids worldwide, including forest habitats. We highlight several implications of scavenging that could considerably improve our understanding of the ecology of vertebrate communities and the evolution of predators as well as benefit the future management and conservation of endangered predators. © 2012 Springer-Verlag.

Culiberg B.,University of Ljubljana
International Journal of Consumer Studies | Year: 2014

Recycling is a post-purchase consumer activity where the consumer usually considers not only individual but also social goals, ideas and ideologies. Accordingly, ethics is an inherent part of recycling; however, very few studies have explored this behaviour from an ethical point of view. The purpose of this paper is to explain consumer recycling by taking a multifaceted ethical approach. The conceptual model builds on theoretical underpinnings related to ethical consumption by exploring the extensions of the theory of planned behaviour, Jones' ethical decision-making model and Holbrook's conceptualization of ethical consumption. Thus, the attitude-intention framework incorporates three ethics-related concepts: (1) moral obligation, i.e. the level of guilt to perform the behaviour, (2) moral intensity, i.e. the moral issue characteristics, and (3) collectivism, i.e. an individual-level value orientation. The data were collected from a sample of Slovenian consumers, using an online consumer panel. The sample reflected the Slovenian population in terms of gender and age. The proposed conceptual model was tested using structural equation modelling. The results suggest the proposed ethical concepts play a significant role in the attitude-intention framework. The more collectivistic individuals have more positive attitudes towards recycling. Moreover, the more consumers perceive recycling as morally intense, the more favourable their attitudes are. In turn, attitudes positively affect intentions to recycle. In addition, higher levels of moral obligation positively influence intentions to recycle. The only hypothesis that is not supported in this study refers to the influence of moral intensity on intentions to recycle. The implications for public policymakers and social marketers stem from a complex interplay of the antecedents of recycling behaviour. Future studies could go in several directions by extending the model to other moral issues, conducting a study in a cross-cultural setting or taking a longitudinal approach. © 2013 John Wiley & Sons Ltd.

Plotkin G.D.,University of Edinburgh | Pretnar M.,University of Ljubljana
Logical Methods in Computer Science | Year: 2013

Algebraic effects are computational effects that can be represented by an equa-tional theory whose operations produce the effects at hand. The free model of this theory induces the expected computational monad for the corresponding effect. Algebraic effects include exceptions, state, nondeterminism, interactive input/output, and time, and their combinations. Exception handling, however, has so far received no algebraic treatment. We present such a treatment, in which each handler yields a model of the theory for exceptions, and each handling construct yields the homomorphism induced by the universal property of the free model. We further generalise exception handlers to arbitrary algebraic effects. The resulting programming construct includes many previously unrelated examples from both theory and practice, including relabelling and restriction in Milner's CCS, timeout, rollback, and stream redirection. © G. D. Plotkin and M. Pretnar.

Cehovin L.,University of Ljubljana | Kristan M.,University of Ljubljana | Leonardis A.,University of Ljubljana | Leonardis A.,University of Birmingham
IEEE Transactions on Pattern Analysis and Machine Intelligence | Year: 2013

This paper addresses the problem of tracking objects which undergo rapid and significant appearance changes. We propose a novel coupled-layer visual model that combines the target's global and local appearance by interlacing two layers. The local layer in this model is a set of local patches that geometrically constrain the changes in the target's appearance. This layer probabilistically adapts to the target's geometric deformation, while its structure is updated by removing and adding the local patches. The addition of these patches is constrained by the global layer that probabilistically models the target's global visual properties, such as color, shape, and apparent local motion. The global visual properties are updated during tracking using the stable patches from the local layer. By this coupled constraint paradigm between the adaptation of the global and the local layer, we achieve a more robust tracking through significant appearance changes. We experimentally compare our tracker to 11 state-of-the-art trackers. The experimental results on challenging sequences confirm that our tracker outperforms the related trackers in many cases by having a smaller failure rate as well as better accuracy. Furthermore, the parameter analysis shows that our tracker is stable over a range of parameter values. © 1979-2012 IEEE.

Aleksovski A.,University of Ljubljana | Dreu R.,University of Ljubljana | Gasperlin M.,University of Ljubljana | Planinsek O.,University of Ljubljana
Expert Opinion on Drug Delivery | Year: 2015

Introduction: Mini-tablets represent a new trend in solid dosage form design, with the main goal of overcoming some therapeutic obstacles such as impaired swallowing and polypharmacy therapy, and also offering some therapeutic benefits such as dose flexibility and combined release patterns. Mini-tablets are a promising patient-friendly drug delivery system.Areas covered: Mini-tablets are tablets with a diameter ≤ 3 mm produced on conventional tablet presses equipped with multiple tooling. Mini-tablet production is similar to the production of standard tablets but requires excellent powder flow due to the small dies, exact control of process parameters and special caution during tablet press assembly in order to avoid tool damage. Mini-tablets (coated or uncoated and single- or multiple-unit systems) are mainly developed as patient-friendly systems for pediatric and geriatric patients and also for personalized medicine because they offer improved swallowing and flexible dosing, combining various release kinetics, doses and active compounds in only one system. Mini-tablets may also be successfully used as multiple-unit modified release systems (extended release, delayed-colon release, pulsatile and bi-modal release and gastroretentive systems) providing improved drug bioavailability compared with single-unit systems.Expert opinion: Mini-tablets used as single- or multiple-unit oral dosage forms have enormous potential as a patient-friendly drug delivery system for targeted populations, providing improved swallowing, flexible dosing and a combination of different release patterns and/or different active compounds (decreasing dosing frequency and/or polypharmacy therapy problems). In terms of complete expression of the benefits of mini-tablets over other oral dosage forms on the market, further investigation in formulation possibilities and development of suitable dosing devices is of essential importance. © 2015 Informa UK, Ltd.

Molek P.,University of Ljubljana | Bratkovic T.,University of Ljubljana
Bioconjugate Chemistry | Year: 2015

Bacteriophages have been exploited as cloning vectors and display vehicles for decades owing to their genetic and structural simplicity. In bipartite display setting, phage takes on the role of a handle to which two modules are attached, each endowing it with specific functionality, much like the Swiss army knife. This concept offers unprecedented potential for phage applications in nanobiotechnology. Here, we compare common phage display platforms and discuss approaches to simultaneously append two or more different (poly)peptides or synthetic compounds to phage coat using genetic fusions, chemical or enzymatic conjugations, and in vitro noncovalent decoration techniques. We also review current reports on design of phage frameworks to link multiple effectors, and their use in diverse scientific disciplines. Bipartite phage display had left its mark in development of biosensors, vaccines, and targeted delivery vehicles. Furthermore, multifunctionalized phages have been utilized to template assembly of inorganic materials and protein complexes, showing promise as scaffolds in material sciences and structural biology, respectively. (Figure Presented). © 2015 American Chemical Society.

Isidori G.,National Institute of Nuclear Physics, Italy | Kamenik J.F.,Jozef Stefan Institute | Kamenik J.F.,University of Ljubljana
Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics | Year: 2011

We analyze a simple Standard Model (SM) extension with only two new light fields: a scalar partner of the top t̄ (with mass above mt) and a light neutral fermion Χ 0 (with mass of a few GeV), coupled to SM quarks via Yukawa interaction. We show that such model can lead to a significant enhancement of the forward-backward asymmetry in tt̄ production at the Tevatron via the additional tt̄ pairs produced from tt̄ † decays. The model satisfies existing constraints on new-physics searches both at low and high energies, and could even address the cosmological dark-matter abundance. The implications for future searches at the LHC are briefly outlined. © 2011 Elsevier B.V.

Rijavec N.,University of Ljubljana | Grubic V.N.,University of Ljubljana
Psychiatria Danubina | Year: 2012

Depression is a common mental disorder with various symptoms and often accompanied with unexplained painful physical symptoms. Patients, especially in primary care, often present only with somatic symptoms and depressed mood is overlooked. On the other hand, psychiatrists don't pay enough attention to somatic or painful symptoms in patients with depression. The connection between depression and accompanying painful physical symptoms is not completely understood although some common neurobiological pathways are proposed. To achieve good clinical outcome all depression symptoms should be recognized and treated. In this review we focus on painful physical symptoms which could not be explained by somatic illness or the intensity can not be explained by physical disease and are attributed to somatic symptoms of depression. The aim of this review is to provide the basic necessary information for clinicians/ psychiatrists on depression with painful physical symptoms, presenting the terminology, epidemiology, differential diagnostics, neurobiological background, psycho-social aspects and treatment strategies. © Medicinska naklada - Zagreb, Croatia.

Klavzar S.,University of Ljubljana | Klavzar S.,University of Maribor
Journal of Combinatorial Optimization | Year: 2013

The Fibonacci cube Γ n is the subgraph of the n-cube induced by the binary strings that contain no two consecutive 1s. These graphs are applicable as interconnection networks and in theoretical chemistry, and lead to the Fibonacci dimension of a graph. In this paper a survey on Fibonacci cubes is given with an emphasis on their structure, including representations, recursive construction, hamiltonicity, degree sequence and other enumeration results. Their median nature that leads to a fast recognition algorithm is discussed. The Fibonacci dimension of a graph, studies of graph invariants on Fibonacci cubes, and related classes of graphs are also presented. Along the way some new short proofs are given. © 2011 Springer Science+Business Media, LLC.

Vrtovec B.,University of Ljubljana
Methodist DeBakey cardiovascular journal | Year: 2013

Heart failure results from injury to the myocardium from a variety of causes, including ischemic and nonischemic etiologies. Severe heart failure carries a 50% 5-year mortality rate and is responsible for more than one-third of cardiovascular deaths in the United States.1 Heart failure progression is accompanied by activation of neurohormonal and cytokine systems as well as a series of adaptive changes within the myocardium, collectively referred to as left ventricular remodelling. The unfavorable alterations may be categorized broadly into changes that occur in the cardiac myocytes and changes that occur in the volume and composition of the extracellular matrix.2 Since remodelling in heart failure is progressive and eventually becomes detrimental, the majority of treatment strategies are aimed at stopping or reversing this process. Although medical management, cardiac resychronization therapy, and long-term or destination mechanical circulatory support have been successful in this regard, a considerable number of patients still progress to end-stage heart failure with limited therapeutic options. For these patients, stem cell therapies are being investigated as a safe treatment strategy for decreasing cardiac remodelling on top of conventional medical and device treatment.

Poredos P.,University of Ljubljana | Jezovnik M.K.,University of Ljubljana
Seminars in Thrombosis and Hemostasis | Year: 2011

Venous thromboembolism (VTE) is one of the most frequent and serious vascular diseases. Although the major risk factors of VTE are well recognized, the pathology often develops in subjects without any obvious precipitating factor. Recent evidence suggests a link between arterial and venous thrombosis, particularly in patients with idiopathic venous thrombosis. Therefore, similar or identical risk factors may play a role in the development of both diseases. A positive association between classical risk factors of atherosclerosis, including dyslipidemia, and VTE has been reported. Recent studies demonstrated an association between hypercholesterolemia and objectively verified VTE. Circulating lipids have been shown to have both prothrombotic- and endothelium-deteriorating properties. Studies suggested a greater generation of thrombin, endothelial dysfunction, and higher platelet activity in hyperlipidemic blood. By impeding these mechanisms, statins may protect against VTE. Observational, controlled studies and two meta-analyses showed that statins significantly reduced VTE risk, most likely in a process independent from cholesterol lowering, through mechanisms related to the pleiotropic effects of these drugs. Currently, it is unknown whether VTE prevention is a class-effect of statins, or if statins differ in their antithrombotic efficacy, and it is also unknown if statin benefit is dose-dependent. However, there are also opposite findings about the efficacy of statins in prevention of VTE. Therefore, the use of statins for prophylaxis of VTE cannot be generally recommended at this stage. Further studies are needed to identify those patients who could eventually benefit maximally from treatment with statins for prevention of VTE. © Georg Thieme Verlag KG Stuttgart - New York.

Introduction: Human papillomavirus (HPV) testing has become an essential part of current clinical practice in the management of cervical cancer and precancerous lesions. We reviewed the most important validation studies of a next-generation real-time polymerase chain reaction-based assay, the RealTime High Risk HPV test (RealTime)(Abbott Molecular, Des Plaines, IL, USA), for triage in referral population settings and for use in primary cervical cancer screening in women 30 years and older published in peer-reviewed journals from 2009 to 2013. RealTime is designed to detect 14 high-risk HPV genotypes with concurrent distinction of HPV-16 and HPV-18 from 12 other HPV genotypes. The test was launched on the European market in January 2009 and is currently used in many laboratories worldwide for routine detection of HPV. Methods: We concisely reviewed validation studies of a next-generation real-time polymerase chain reaction (PCR)-based assay: the Abbott RealTime High Risk HPV test. Results: Eight validation studies of RealTime in referral settings showed its consistently high absolute clinical sensitivity for both CIN2+ (range 88.3-100%) and CIN3+ (range 93.0-100%), as well as comparative clinical sensitivity relative to the currently most widely used HPV test: the Qiagen/Digene Hybrid Capture 2 HPV DNATest (HC2). Due to the significantly different composition of the referral populations, RealTime absolute clinical specificity for CIN2+ and CIN3+ varied greatly across studies, but was comparable relative to HC2. Four validation studies of RealTime performance in cervical cancer screening settings showed its consistently high absolute clinical sensitivity for both CIN2+ and CIN3+, as well as comparative clinical sensitivity and specificity relative to HC2 and GP5+/6+ PCR. Conclusion: RealTime has been extensively evaluated in the last 4 years. RealTime can be considered clinically validated for triage in referral population settings and for use in primary cervical cancer screening in women 30 years and older.

Kodek D.M.,University of Ljubljana
IEEE Transactions on Signal Processing | Year: 2012

In practical finite-impulse-response (FIR) digital filter applications, it is often necessary to represent the filter coefficients with a finite number of bits. The finite wordlength restriction increases the filter deviation. This increase can be reduced substantially if the optimal finite wordlength coefficients are used. The time needed to compute these coefficients is greatly reduced with the help of a lower bound on the deviation increase. Derivation of an improved lower bound that uses the well-known LLL algorithm is presented in this correspondence. © 2011 IEEE.

Rizner T.L.,University of Ljubljana
Frontiers in Pharmacology | Year: 2016

Gynecological diseases such as endometriosis, adenomyosis and uterine fibroids, and gynecological cancers including endometrial cancer and ovarian cancer, affect a large proportion of women. These diseases are estrogen dependent, and their progression often depends on local estrogen formation. In peripheral tissues, estrogens can be formed from the inactive precursors dehydroepiandrosterone sulfate and estrone sulfate. Sulfatase and sulfotransferases have pivotal roles in these processes, where sulfatase hydrolyzes estrone sulfate to estrone, and dehydroepiandrosterone sulfate to dehydroepiandrosterone, and sulfotransferases catalyze the reverse reactions. Further activation of estrone to the most potent estrogen, estradiol, is catalyzed by 17-ketosteroid reductases, while estradiol can also be formed from dehydroepiandrosterone by the sequential actions of 3β-hydroxysteroid dehydrogenase-Δ4-isomerase, aromatase, and 17-ketosteroid reductase. This review introduces the sulfatase and sulfotransferase enzymes, in terms of their structures and reaction mechanisms, and the regulation and different transcripts of their genes, together with the importance of their currently known single nucleotide polymorphisms. Data on expression of sulfatase and sulfotransferases in gynecological diseases are also reviewed. There are often unchanged mRNA and protein levels in diseased tissue, with higher sulfatase activities in cancerous endometrium, ovarian cancer cell lines, and adenomyosis. This can be indicative of a disturbed balance between the sulfatase and sulfotransferases enzymes, defining the potential for sulfatase as a drug target for treatment of gynecological diseases. Finally, clinical trials with sulfatase inhibitors are discussed, where two inhibitors have already concluded phase II trials, although so far with no convincing clinical outcomes for patients with endometrial cancer and endometriosis. © 2016 Rižner.

Pulko B.,University of Ljubljana | Majes B.,University of Ljubljana | Logar J.,University of Ljubljana
Geotextiles and Geomembranes | Year: 2011

This paper presents a newly developed design method for non-encased and encased stone columns. The developed analytical closed-form solution is based on previous solutions, initially developed for non-encased columns and for non-dilating rigid-plastic column material. In the present method, the initial stresses in the soil/column are taken into account, with the column considered as an elasto-plastic material with constant dilatancy, the soil as an elastic material and the geosynthetic encasement as a linear-elastic material. To check the validity of the assumptions and the ability of the method to give reasonable predictions of settlements, stresses and encasement forces, comparative elasto-plastic finite element analyses have been performed. The agreement between the two methods is very good, which was the reason that the new method was used to generate a parametric study in order to investigate various parameters, such as soil/column parameters, replacement ratio, load level and geosynthetic encasement stiffness on the behaviour of the improved ground. The results of this study show the influence of key parameters and provide a basis for the rational predictions of settlement response for various encasement stiffnesses, column arrangements and load levels. The practical use of the method is illustrated through the design chart, which enables preliminary selection of column spacing and encasement stiffness to achieve the desired settlement reduction for the selected set of the soil/column parameters. © 2010 Elsevier Ltd.

Mikulic-Petkovsek M.,University of Ljubljana | Slatnar A.,University of Ljubljana | Stampar F.,University of Ljubljana | Veberic R.,University of Ljubljana
Food Chemistry | Year: 2012

Berries and red fruits are rich dietary sources of polyphenols with reported health benefits. More than 50 different flavonols (glycosides of quercetin, myricetin, kaempferol, isorhamnetin, syringetin and laricitrin) have been detected and quantified with HPLC-MS n in fruits of blueberry, bilberry, cranberry, lingonberry, eastern shadbush, Japanese wineberry, black mulberry, chokeberry, red, black and white currants, jostaberry, red and white gooseberry, hardy kiwifruit, goji berry, rowan, dog rose, Chinese and midland hawthorn, wild and cultivated species of blackberry, raspberry, strawberry and elderberry. The phenolic constituents and contents varied considerably among the analyzed berry species. Elderberry contained the highest amount of total flavonols (450-568 mg kg -1 FW), followed by berry species, containing more than 200 mg kg -1 FW of total: chokeberry (267 mg kg -1), eastern shadbush (261 mg kg -1), wild grown blackberry (260 mg kg -1), rowanberry (232 mg kg -1), american cranberry (213 mg kg -1) and blackcurrants (204 mg kg -1). Strawberry (10.5 mg kg -1) and white currants (4.5 mg kg -1) contained the lowest amount of total flavonols. Quercetins represent the highest percentage (46-100%) among flavonols in most analyzed berries. In wild strawberry and gooseberry the prevailing flavonols belong to the group of isorhamnetins (50-62%) and kaempferols, which represent the major part of flavonols in currants (49-66%). Myricetin glycosides could only be detected in chokeberry, rowanberry and species from the Grossulariaceae, and Adoxaceae family and Vaccinium genus. Wild strawberry and blackberry contained from 3- to 5-fold higher total flavonols than the cultivated one. © 2012 Elsevier Ltd. All rights reserved.

Likar M.,University of Ljubljana | Regvar M.,University of Ljubljana
Plant and Soil | Year: 2013

Background and aims: Dark septate endophyte (DSE) fungi are the most frequent colonists on the roots of Salix caprea in highly metal-contaminated soils. The present study was performed to obtain insights into the physiology and potential role(s) of DSE fungi for Salix caprea growing in metal-enriched sites. Methods: Fungal isolates from S. caprea roots were identified using molecular methods, and tested for their tolerance and metal accumulation in axenic cultures. In addition, an inoculation experiment was performed to monitor the effects of the fungi on the metal uptake by the plant host. Fitness of S. caprea cuttings was assessed by photosynthetic pigment quantification and measurements of transpiration. Results: Fungal isolates were identified as members of the Phialophora/Cadophora complex. They showed different levels of metal tolerance and maintained growth on metal-enriched media. In comparison to non-inoculated cuttings, the DSE-inoculated cuttings had lower leaf Cd content, and for isolates DB146 and DB148, also lower Zn concentrations. All DSE isolates increased the chlorophyll levels of the cuttings, with isolate DB146 also positively affecting the transpiration rate of S. caprea. Conclusions: Our findings suggest that DSE reduced the metal uptake by the S. caprea cuttings, thus suggesting a beneficial role for S. caprea in metal-enriched soils. © 2013 Springer Science+Business Media Dordrecht.

Pangerc U.,University of Ljubljana | Jager F.,University of Ljubljana
Computing in Cardiology | Year: 2014

We developed a new, robust and efficient heart beat detector in multimodal data using an ECG signal, and one of the pulsatile signals such as blood pressure (BP), if present. To calculate the detection functions, simple and fast integer-multiplier sampling-frequency adjustable digital filters were developed. Using the morphological smoothing, the ECG and pulsatile-signal detection functions, and the noise detection function, are improved. Heart beats are detected using gain-independent adjustable detection thresholds. Streams of detected heart beats in the ECG and in pulsatile signal are linked together. Real time implementation is possible.

Kreslin M.,University of Ljubljana | Fajfar P.,University of Ljubljana
Earthquake Engineering and Structural Dynamics | Year: 2011

The N2 method has been extended in order to take into account higher mode effects in elevation. The extension is based on the assumption that the structure remains in the elastic range when vibrating in higher modes. The seismic demand in terms of displacements and storey drifts can be obtained by enveloping the results of basic pushover analysis and the results of standard elastic modal analysis. The approach is consistent with the extended N2 method used for plan-asymmetric buildings. The proposed procedure was applied to three variants of three steel frame buildings used in the SAC project. The structural response was investigated for two sets of ground motions. Different ground motion intensities were used in order to investigate the influence of the magnitude of plastic deformations. The N2 results were compared with the results of nonlinear response-history analysis, two other pushover-based methods (modal pushover analysis (MPA) and modified MPA (MMPA)), and pushover analysis without consideration of higher modes. It was found that a considerable influence of higher modes on storey drifts is present at the upper part of medium-and high-rise structures. This effect is the largest in the case of elastic behaviour and decreases with ground motion intensity. The higher mode effects also depend on the spectral shape. The approximate methods (extended N2, MPA and MMPA) are able to provide fair estimates of response in the case of the test examples. Accuracy decreases with the height of the building, and with the intensity of ground motion. The N2 results are generally conservative. © 2011 John Wiley & Sons, Ltd.

Golicnik M.,University of Ljubljana
Biochemistry and Molecular Biology Education | Year: 2011

The Michaelis-Menten rate equation can be found in most general biochemistry textbooks, where the time derivative of the substrate is a hyperbolic function of two kinetic parameters (the limiting rate V, and the Michaelis constant KM) and the amount of substrate. However, fundamental concepts of enzyme kinetics can be difficult to understand fully, or can even be misunderstood, by students when based only on the differential form of the Michaelis-Menten equation, and the variety of methods available to calculate the kinetic constants from rate versus substrate concentration "textbook data." Consequently, enzyme kinetics can be confusing if an analytical solution of the Michaelis-Menten equation is not available. Therefore, the still rarely known exact solution to the Michaelis-Menten equation is presented here through the explicit closed-form equation in terms of the Lambert W(x) function. Unfortunately, as the W(x) is not available in standard curve-fitting computer programs, the practical use of this direct solution is limited for most life-science students. Thus, the purpose of this article is to provide analytical approximations to the equation for modeling Michaelis-Menten kinetics. The elementary and explicit nature of these approximations can provide students with direct and simple estimations of kinetic parameters from raw experimental time-course data. The Michaelis-Menten kinetics studied in the latter context can provide an ideal alternative to the 100-year-old problems of data transformation, graphical visualization, and data analysis of enzyme-catalyzed reactions. Hence, the content of the course presented here could gradually become an important component of the modern biochemistry curriculum in the 21st century. Copyright © 2011 Wiley Periodicals, Inc.

Koren D.,University of Ljubljana | Kilar V.,University of Ljubljana
Earthquake Engineering and Structural Dynamics | Year: 2011

The paper deals with the applicability of the extended N2 method to base-isolated plan-asymmetric building structures. The results obtained by the usual pushover analysis of a 3D structural model are further combined with the aid of linear dynamic (spectral) analysis to account for the dynamic effects caused by structural asymmetry. In the paper, the method has been applied to the seismic analysis of a mass-eccentric four-storeyed RC frame building isolated with lead rubber bearings. Three different positions of the center of isolation system (CI) with respect to the center of mass (CM) and the center of stiffness of the superstructure (CS) were considered. The response was analyzed for three different eccentricities, three different torsional to lateral frequency ratios of the superstructure, and two ground motion intensities. The stiffness of the isolators was selected for three different protection levels, which resulted in elastic as well as moderately to excessively damaged superstructure performance levels. The results are presented in terms of the top, base and relative displacements, as well as the stiff/flexible side amplification factors. A more detailed insight into the nonlinear behavior of the superstructure is given in a form of ductility factors for the flexible and stiff side frames. The results of the extended N2 method for selected lateral load distributions are compared with the average results of nonlinear dynamic analyses. It was concluded that the extended N2 method could, with certain limitations, provide a reasonable prediction of the torsional influences in minor to moderately asymmetric base-isolated structures. © 2010 John Wiley & Sons, Ltd.

Mozina J.,University of Ljubljana | Diaci J.,University of Ljubljana
Applied Physics B: Lasers and Optics | Year: 2011

The term optodynamics has been introduced to describe a wide range of optically induced dynamic phenomena, which play an important role in laser-material processes as well as in laser-assisted medical applications. In view of laser material processing, a laser beam is not only considered as a tool, but also as a generator of information about the material's transformation. The information is retained and conveyed by different kinds of optically induced mechanical motions, such as shock, acoustic and ultrasound waves, and cavitation bubbles. Special emphasis is given to the recent investigations of linear momentum transformation during the laser-material interaction and to the on-line monitoring of laser material processing. © Springer-Verlag 2011.

Battelino T.,University of Ljubljana | Phillip M.,Tel Aviv University | Bratina N.,University of Ljubljana | Nimri R.,Tel Aviv University | And 2 more authors.
Diabetes Care | Year: 2011

OBJECTIVE - To assess the impact of continuous glucose monitoring on hypoglycemia in people with type 1 diabetes. RESEARCH DESIGN AND METHODS - In this randomized, controlled, multicenter study, 120 children and adults on intensive therapy for type 1 diabetes and a screening level of glycated hemoglobin A1c (HbA1c) <7.5% were randomly assigned to a control group performing conventional home monitoring with a blood glucose meter and wearing a masked continuous glucose monitor every second week for five days or to a group with real-time continuous glucose monitoring. The primary outcome was the time spent in hypoglycemia (interstitial glucose concentration <63 mg/dL) over a period of 26 weeks. Analysis was by intention to treat for all randomized patients. RESULTS - The time per day spent in hypoglycemia was significantly shorter in the continuous monitoring group than in the control group (mean ± SD 0.48 ± 0.57 and 0.97 ± 1.55 h/day, respectively; ratio of means 0.49; 95% CI 0.26-0.76; P = 0.03). HbA1c at 26 weeks was lower in the continuous monitoring group than in the control group (difference 20.27%; 95% CI-0.47 to -0.07; P = 0.008). Time spent in 70 to 180 mg/dL normoglycemia was significantly longer in the continuous glucose monitoring group compared with the control group (mean hours per day, 17.6 vs. 16.0, P = 0.009). CONCLUSIONS - Continuous glucose monitoring was associated with reduced time spent in hypoglycemia and a concomitant decrease in HbA 1c in children and adults with type 1 diabetes. © 2011 by the American Diabetes Association.

Tica D.,University of Ljubljana | Udovic M.,University of Ljubljana | Lestan D.,University of Ljubljana
Chemosphere | Year: 2011

The in situ stabilization of potentially toxic metals (PTMs), using various easily available amendments, is a cost-effective remediation method for contaminated soils. In the present study, we investigated the effectiveness of apatite and a commercial mixture of dolomite, diatomite, smectite basaltic tuff, bentonite, alginite and zeolite (Slovakite) on Pb, Zn, Cu and Cd stabilization by means of decreasing their bioavailability in contaminated soil from an old lead and zinc smelter site in Arnoldstein, Austria. We also investigated the impact of 5% (w/w) apatite and Slovakite applications on soil functionality and quality, as assessed by glucose-induced soil respiration, dehydrogenase, acid and alkaline phosphatase and β-glucosidase activity. Both amendments resulted in increased soil pH and decreased PTM potential bioavailability assessed by diethylenetriamine pentaacetic acid extraction and by sequential extractions in the water-soluble and exchangeable fractions. The efficiency of stabilization was reflected in the soil respiration rate and in enzymatic activity. The β-glucosidase activity assay was the most responsive of them. © 2011 Elsevier Ltd.

Hlebec V.,University of Ljubljana
Zdravstveno Varstvo | Year: 2014

Theory: Social homecare is important for older people, as it enables them to remain in their own homes during worsening health, thus relieving the burden on institutional facilities such as homes for the elderly or nursing homes and hospitals. Method: A representative survey of social homecare users was employed to assess determinants of the scope of social homecare in Slovenia. Multiple regression analysis was used to evaluate determinants defined by Andersen's behavioral model that affect the scope of social homecare. Results: As expected, need (Functional impairment B =.378, P = 0.000) was the most important explanatory component, followed by availability of informal care network (Lives alone B = -.136, P = 0.000; Has children B = -.142; P = 0.000) and other contextual factors such as total costs of the services (B = -.075; P = 0.003) and temporal availability of services (B=-.075, P=0.012). The model explained 18% of variability in the scope of social homecare. Conclusion: This study showed that data on the individual level, as opposed to data on an aggregated level, show different determinants of social homecare utilization. Moreover, the results showed that social homecare is especially important in two circumstances: when older people have a high level of need and when they do not have access to informal care networks. Contextual factors had a moderate effect on the scope of social homecare, which shows universal access to the latter at the individual level.

Kogoj A.,University of Ljubljana
Psychiatria Danubina | Year: 2014

Background: Many commonly used medications are associated with causing delirium, especially those with notable direct effects on the brain. Selective serotonin reuptake inhibitors (SSRIs) are probably the most often prescribed antidepressants and are known for their favourable side-effect profile. Methods: Medline and Toxline databases were searched for case reports of delirium caused by SSRIs. Twelve cases were reviewed in addition to our case of escitalopram-induced delirium in old age. Results: Only five cases of delirium due to SSRIs as the main or most probable etiologic factor were published in the last two decades. In two cases SSRI seems a possible additional cause of delirium in combination with other psychotropic medication. Conclusions: Although SSRIs are considered safe, they can still cause delirium in an ageing patient even when SSRI was previously used without considerable side effects. © Medicinska naklada.

Mervic L.,University of Tübingen | Mervic L.,University of Ljubljana
PLoS ONE | Year: 2012

Background: This study identified sex differences in progression of cutaneous melanoma. Methodology/Principal Findings: Of 7,338 patients who were diagnosed as an invasive primary CM without clinically detectable metastases from 1976 to 2008 at the University of Tuebingen in Germany, 1,078 developed subsequent metastases during follow up. The metastatic pathways were defined in these patients and analyzed using the Kaplan-Meier method. Multivariate survival analysis was performed using Cox modeling. In 18.7% of men and 29.2% of women (P<0.001) the first metastasis following diagnosis of primary tumor was locoregional as satellite/in-transit metastasis. The majority of men (54.0%) and women (47.6%, P = 0.035) exhibited direct regional lymph node metastasis. Direct distant metastasis from the stage of the primary tumor was observed in 27.3% of men and 23.2% of women (P = 0.13). Site of first metastasis was the most important prognostic factor of survival after recurrence in multivariate analysis (HR:1.3; 95% CI: 1.0-1.6 for metastasis to the regional lymph nodes vs. satellite/in-transit recurrence, and HR:5.5; 95% CI: 4.2-7.1 for distant metastasis vs. satellite/in-transit recurrence, P<0.001). Median time to distant metastasis was 40.5 months (IQR, 58.75) in women and 33 months (IQR, 44.25) in men (P = 0.002). Five-year survival after distant recurrence probability was 5.2% (95% CI: 1.4-2.5) for men compared with 15.3% (95% CI: 11.1-19.5; P = 0.008) for women. Conclusions/Significance: Both, the pattern of metastatic spread with more locoregional metastasis in women, and the time course with retracted metastasis in women contributed to the more favorable outcome of women. Furthermore, the total rate of metastasis is increased in men. Interestingly, there is also a much more favorable long term survival of women after development of distant metastasis. It remains a matter of debate and of future research, whether hormonal or immunologic factors may be responsible for these sex differences. © 2012 Liljana Mervic.

Kreft M.E.,University of Ljubljana | Robenek H.,University of Munster
PLoS ONE | Year: 2012

The primary function of the urothelium is to provide the tightest and most impermeable barrier in the body, i.e. the blood-urine barrier. Urothelial plaques are formed and inserted into the apical plasma membrane during advanced stages of urothelial cell differentiation. Currently, it is supposed that differentiation with the final formation of urothelial plaques is hindered in cultured urothelial cells. With the aid of the high-resolution imaging technique of freeze-fracture replica immunolabelling, we here provide evidence that urothelial cells in vitro form uroplakin-positive urothelial plaques, localized in fusiform-shaped vesicles and apical plasma membranes. With the establishment of such an in vitro model of urothelial cells with fully developed urothelial plaques and functional properties equivalent to normal bladder urothelium, new perspectives have emerged which challenge prevailing concepts of apical plasma membrane biogenesis and blood-urine barrier development. This may hopefully provide a timely impulse for many ongoing studies and open up new questions for future research. © 2012 Kreft, Robenek.

Trcek D.,University of Ljubljana
Sensors (Switzerland) | Year: 2012

Trust plays a key role not only in e-worlds and emerging pervasive computing environments, but also already for millennia in human societies. Trust management solutions that have being around now for some fifteen years were primarily developed for the above mentioned cyber environments and they are typically focused on artificial agents, sensors, etc. However, this paper presents extensions of a new methodology together with architecture for trust management support that is focused on humans and human-like agents. With this methodology and architecture sensors play a crucial role. The architecture presents an already deployable tool for multi and interdisciplinary research in various areas where humans are involved. It provides new ways to obtain an insight into dynamics and evolution of such structures, not only in pervasive computing environments, but also in other important areas like management and decision making support. © 2012 by the authors; licensee MDPI, Basel, Switzerland.

Humar M.,Jozef Stefan Institute | Musevic I.,Jozef Stefan Institute | Musevic I.,University of Ljubljana
Optics Express | Year: 2011

Lasing of whispering-gallery modes in nematic liquid-crystal microdroplets, floating in water, is demonstrated. It is shown that millimolar concentrations of sodium dodecyl sulfate in water effect the orientation of liquid-crystal molecules in the microdroplet, which changes the lasing spectrum. The presence of targeted molecules in water can be monitored by simply measuring and recognizing the spectrum of light, lasing from a small liquid-crystal droplet in water. © 2011 Optical Society of America.

David E.,Romanian Institute of Isotopic And Molecular Technology | Kopac J.,University of Ljubljana
Journal of Hazardous Materials | Year: 2012

A simple method with high efficiency for generating high pure hydrogen by hydrolysis in tap water of highly activated aluminum dross is established. Aluminum dross is activated by mechanically milling to particles of about 45μm. This leads to removal of surface layer of the aluminum particles and creation of a fresh chemically active metal surface. In contact with water the hydrolysis reaction takes place and hydrogen is released. In this process a Zero Waste concept is achieved because the other product of reaction is aluminum oxide hydroxide (AlOOH), which is nature-friendly and can be used to make high quality refractory or calcium aluminate cement. For comparison we also used pure aluminum powder and alkaline tap water solution (NaOH, KOH) at a ratio similar to that of aluminum dross content. The rates of hydrogen generated in hydrolysis reaction of pure aluminum and aluminum dross have been found to be similar. As a result of the experimental setup, a hydrogen generator was designed and assembled. Hydrogen volume generated by hydrolysis reaction was measured. The experimental results obtained reveal that aluminum dross could be economically recycled by hydrolysis process with achieving zero hazardous aluminum dross waste and hydrogen generation. © 2012 Elsevier B.V.

Van Beers J.J.B.C.,Radboud University Nijmegen | Schwarte C.M.,Radboud University Nijmegen | Stammen-Vogelzangs J.,Radboud University Nijmegen | Oosterink E.,Radboud University Nijmegen | And 2 more authors.
Arthritis and Rheumatism | Year: 2013

Objective To generate a catalog of citrullinated proteins that are present in the synovia of patients with rheumatoid arthritis (RA) and to elucidate their relevance for the anti-citrullinated protein antibody response in RA. Methods Polypeptides isolated from the synovial fluid of patients with RA were identified by mass spectrometry. Three proteins (apolipoprotein E [Apo E], myeloid nuclear differentiation antigen [MNDA], and β-actin) were studied in more detail, using immunoprecipitation and Western blotting. The presence of autoantibodies to synthetic peptides derived from these proteins in sera from patients with RA, sera from patients with other diseases, and sera from healthy control subjects was studied by enzyme-linked immunosorbent assay (ELISA). Results RA synovial fluid samples displayed several distinct patterns of citrullinated proteins. Using mass spectrometry, (fragments of) 192 proteins were identified, including 53 citrullinated proteins, some of which contained multiple citrullinated residues. In addition to previously reported citrullinated proteins in RA synovia (e.g., vimentin and fibrinogen), a series of novel citrullinated proteins, including Apo E, MNDA, β-actin, and cyclophilin A, was identified. Immunoprecipitation experiments confirmed the citrullination of Apo E and MNDA. ELISAs demonstrated the presence of autoreactive citrullinated epitopes in Apo E, MNDA, and β-actin. Conclusion Synovial fluid samples from the inflamed joints of patients with RA contain many citrullinated proteins. Citrullinated Apo E, MNDA, and β-actin are novel antigens identified in RA synovial fluid, and only a limited number of their citrullinated epitopes are targeted by the immune system in RA. Copyright © 2013 by the American College of Rheumatology.

Znidaric M.,National Autonomous University of Mexico | Znidaric M.,University of Ljubljana
Physical Review Letters | Year: 2011

We analytically and numerically study spin transport in a one-dimensional Heisenberg model in linear-response regime at infinite temperature. It is shown that as the anisotropy parameter Δ is varied spin transport changes from ballistic for Δ<1 to anomalous at the isotropic point Δ=1, to diffusive for finite Δ>1, ending up as a perfect isolator in the Ising limit of infinite Δ. Using perturbation theory for large Δ a quantitative prediction is made for the dependence of diffusion constant on Δ. © 2011 American Physical Society.

Likozar B.,Slovenian National Institute of Chemistry | Levec J.,University of Ljubljana
Fuel Processing Technology | Year: 2014

Detailed reaction kinetics of oil transesterification were studied based on mechanism and reaction scheme of individual triglyceride, diglyceride, monoglyceride, glycerol and fatty acid methyl ester containing different combinations of gadoleic, linoleic, linolenic, oleic, palmitic and stearic acids determined by high-performance liquid chromatography. Pre-exponential factors and activation energies were correlated with molecular structure in terms of chain lengths and double bonds by response surface models. The activation energies of forward reactions were 47-61 kJ mol- 1 with backward ones being 31-49 kJ mol- 1, depending on component structure. Mass transfer during initial emulsion phase was acknowledged by determining diffusivities, distribution coefficients, molar volumes, boiling points and viscosities of individual components. Model was validated for a wide range of temperatures, hydrodynamic conditions, dispersed and continuous phase ratios, and methanolysis catalyst concentrations. Rotational speed had the most profound influence on the duration of transport phenomena-limited region spanning the latter to 27 min upon use of 100 rpm. Economics of the process were finally evaluated in terms of alcoholysis cost and price breakdown. Proposed methodology may be usefully applied to transesterification syntheses employing heterogeneous catalysis and enzymes, as well as various renewable resources such as microalgae lipids, waste oils, bioethanol and biobutanol. © 2014 Elsevier B.V.

Lengiewicz J.,Polish Institute of Fundamental Technological Research | Korelc J.,University of Ljubljana | Stupkiewicz S.,Polish Institute of Fundamental Technological Research
International Journal for Numerical Methods in Engineering | Year: 2011

The aim of this paper is to present a general method for automation of finite element formulations of large deformation contact problems. A new automatic-differentiation-based notation is introduced that represents a bridge between the classical mathematical notation of contact mechanics and the actual computer implementation of contact finite elements. Automation of derivation of the required formulas (e.g. element residual and tangent matrix) combined with automatic code generation makes the finite element implementation possible at a moderate effort. Accordingly, several 3D contact formulations have been implemented in this work, including penalty and augmented Lagrangian treatments of contact constraints, and several contact smoothing techniques. A typical benchmark problem could thus be executed in an objective way leading to a comprehensive study of the efficiency and the accuracy of various formulations of 3D contact finite elements. Copyright © 2010 John Wiley & Sons, Ltd.

Znidaric M.,University of Ljubljana
Journal of Physics A: Mathematical and Theoretical | Year: 2010

A one-dimensional XX spin chain of finite length coupled to reservoirs at both ends is solved exactly in terms of a matrix product state ansatz. An explicit representation of matrices of fixed dimension 4 independent of the chain length is found. Expectations of all observables are evaluated, showing that all connected correlations, apart from the nearest neighbor z-z, are zero. © 2010 IOP Publishing Ltd.

Turk B.,Jozef Stefan Institute | Turk B.,University of Ljubljana | Turk D.,Jozef Stefan Institute | Turk V.,Jozef Stefan Institute
EMBO Journal | Year: 2012

Protease research has undergone a major expansion in the last decade, largely due to the extremely rapid development of new technologies, such as quantitative proteomics and in-vivo imaging, as well as an extensive use of in-vivo models. These have led to identification of physiological substrates and resulted in a paradigm shift from the concept of proteases as protein-degrading enzymes to proteases as key signalling molecules. However, we are still at the beginning of an understanding of protease signalling pathways. We have only identified a minor subset of true physiological substrates for a limited number of proteases, and their physiological regulation is still not well understood. Similarly, links with other signalling systems are not well established. Herein, we will highlight current challenges in protease research. © 2012 European Molecular Biology Organization | All Rights Reserved.

Hocevar T.,University of Ljubljana | Demsar J.,University of Ljubljana
Bioinformatics | Year: 2014

Motivation: Small-induced subgraphs called graphlets are emerging as a possible tool for exploration of global and local structure of networks and for analysis of roles of individual nodes. One of the obstacles to their wider use is the computational complexity of algorithms for their discovery and counting.Results: We propose a new combinatorial method for counting graphlets and orbit signatures of network nodes. The algorithm builds a system of equations that connect counts of orbits from graphlets with up to five nodes, which allows to compute all orbit counts by enumerating just a single one. This reduces its practical time complexity in sparse graphs by an order of magnitude as compared with the existing pure enumeration-based algorithms.Availability and implementation: Source code is available freely at http://www.biolab.si/supp/ orca/orca.html.Contact: Supplementary information: Supplementary data are available at Bioinformatics online. © 2013 The Author.

Cemazar J.,University of Ljubljana | Kotnik T.,University of Ljubljana
Electrophoresis | Year: 2012

We describe the development and testing of a setup that allows for DEP field-flow fractionation (DEP-FFF) of irreversibly electroporated, reversibly electroporated, and nonelectroporated cells based on their different polarizabilities. We first optimized the channel and electrode dimensions, flow rate, and electric field parameters for efficient DEP-FFF separation of moderately heat-treated CHO cells (50°C for 15 min) from untreated ones, with the former used as a uniform and stable model of electroporated cells. We then used CHO cells exposed to electric field pulses with amplitudes from 1200 to 2800 V/cm, yielding six groups containing various fractions of nonporated, reversibly porated, and irreversibly porated cells, testing their fractionation in the chamber. DEP-FFF at 65 kHz resulted in distinctive flow rates for nonporated and each of the porated cell groups. At lower frequencies, the efficiency of fractionation deteriorated, while at higher frequencies the separation of individual elution profiles was further improved, but at the cost of cell flow rate slowdown in all the cell groups, implying undesired transition from negative into positive DEP, where the cells are pulled toward the electrodes. Our results demonstrate that fractionation of irreversibly electroporated, reversibly electroporated, and nonelectroporated cells is feasible at a properly selected frequency. © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Igor D.,University of Ljubljana
Key Engineering Materials | Year: 2016

We discuss the impact of residual stresses, caused by variation in external temperature field due to mismatch in thermal and elastic material properties in dissimilar two-phase system composed of a thin film and a flexible substrate, on failure behavior of the system. In the process of modeling, a representative volume element of the system is defined as a heterogeneous two-phase layered element bonded at an interface in a sense of coherent bi-layer with classical interface conditions, which can be described as a sharp interface. We use a spatial averaging technique in transversal direction of the element with particular form of strain field that satisfies compatibility equations in the bulk and at the interface. With developed methodology we are able to determine residual stress distribution through thickness of the representative volume element. With known distribution of the stress field, we formulate a corresponding failure criterion in the form of characteristic failure surfaces. © (2016) Trans Tech Publications, Switzerland.

Urban researchers have acknowledged that current urban design tools do not sufficiently take into account the complexity of various social factors (integration of the community, local economy, identity of the community, etc.) into the implementation processes of new (sustainable) urban areas. Since the best practices of successful sustainable neighbourhoods are too little known and are not taken into account in urban design tools, because there is no existing comparative analysis of best practices that would provide common guidelines for the implementation of new autonomous sustainable neighbourhoods (ASN), the central objective of the article focuses on creating an interdisciplinary structure for a holistic model of autonomous sustainable neighbourhoods. The aim of the article is to create a framework of strategic urban sustainability goals that derives from "good examples" of sustainable neighbourhoods and that could represent a new mode of interdisciplinary urban planning, emphasizing the importance of the socio-economic factors in neighbourhood modelling. The article will try to identify a concrete scheme of sustainable elements, which could facilitate the creation of new sustainable districts in cities (with due regard to local specifics). The structural model of autonomous sustainable neighbourhoods could be suitable as a tool for the implementation of strategic urban sustainability goals and might upgrade existing sustainable urban planning tools. The proposed model, which is based on a comparative analysis of the best practices of sustainable neighbourhoods in Europe, is formed and structured by "the four pillars of urban sustainability" (Energy pillar and natural resources, Sustainable Transport, Socio-economic balance, and Sustainable urban design elements). Each of the "pillars" incorporates several "strategic urban sustainability goals". © 2016 Elsevier Ltd.

Innovative analytically based method to calculate corrected fuel consumption of parallel and series hybrid electric vehicles (HEVs) at balanced energy content of the electric storage devices is proposed and validated in the paper. The proposed analytical method is generally applicable and features highly accurate corrected fuel consumption results. It enables calculation of the corrected fuel consumption out of a single fuel consumption test run in a single analytic post-processing step. An additional fuel consumption test run might be needed to obtain highly accurate results if ratio of the energy content deviation of the electric storage devices to the energy used for vehicle propulsion over the test cycle is high. Proposed method enables consideration of non-linear energy flow changes and non-linear HEV component efficiency changes caused by the energy management strategy or by the component characteristics. The method therefore features highly accurate results out of the minimum number of fuel consumption test runs and thus optimizes workload for development or optimization of HEVs. The input data of the method are characteristic energy flows and efficiencies that are derived from the energy flows on selected energy paths of HEVs. © 2010 Elsevier Ltd.

Podnar S.,University of Ljubljana
Neurourology and Urodynamics | Year: 2014

Aims Sacral neurophysiologic studies have demonstrated their utility in men with suspected neurogenic sacral dysfunction. However, no similar studies have been performed in women. The present study aimed to test the utility of sacral neurophysiologic assessment in women with chronic cauda equina lesions. Methods Twenty-four women with clinical and radiological signs supportive of chronic cauda equina lesions, and a group of 60 control women without clinical symptoms or signs of sacral neuropathic lesion were included. Clinical examination, including testing of saddle sensation, and neurophysiologic testing, including quantitative anal sphincter EMG and clitoro-cavernosus reflex testing (on single and double electrical, and mechanical stimulation), were performed on each side separately. Sensitivity, specificity, positive predictive value, and negative predictive value were calculated. Results Respective sensitivities, specificities, positive predictive values, and negative predictive values were 63%, 92%, 83%, and 86% for quantitative anal sphincter EMG, 92-96%, 67-80%, 52-59%, and 95-96% for neurophysiologic testing of the clitoro-cavernosus reflex (using different stimulation techniques), and 96-100%, 62-75%, 50-55%, and 97-98% for their combinations. Conclusions This study complements previous reports in men supporting the clinical utility of an neurophysiologic protocol that includes both quantitative anal sphincter EMG and sacral reflex studies for assessment of patients with suspected peripheral sacral lesions. Very high sensitivity and negative predictive value confirm high utility of sacral neurophysiologic studies in confirmation and exclusion of sacral neuropathic lesion. © 2014 Wiley Periodicals, Inc.

Tadina M.,University of Ljubljana | Boltezar M.,University of Ljubljana
Journal of Sound and Vibration | Year: 2011

In this paper an improved bearing model is developed in order to investigate the vibrations of a ball bearing during run-up. The numerical bearing model was developed with the assumptions that the inner race has only 2 DOF and that the outer race is deformable in the radial direction, and is modelled with finite elements. The centrifugal load effect and the radial clearance are taken into account. The contact force for the balls is described by a nonlinear Hertzian contact deformation. Various surface defects due to local deformations are introduced into the developed model. The detailed geometry of the local defects is modelled as an impressed ellipsoid on the races and as a flattened sphere for the rolling balls. With the developed bearing model the transmission path of the bearing housing can be taken into account, since the outer ring can be coupled with the FE model of the housing. The obtained equations of motion were solved numerically with a modified Newmark time-integration method for the increasing rotational frequency of the shaft. The simulated vibrational response of the bearing with different local faults was used to test the suitability of the envelope analysis technique and the continuous wavelet transformation was used for the bearing-fault identification and classification. © 2011 Elsevier Ltd.

Perse M.,University of Ljubljana | Injac R.,University of Ljubljana | Erman A.,University of Ljubljana
PLoS ONE | Year: 2013

Age-related changes in various tissues have been associated with the onset of a number of age-related diseases, including inflammation and cancer. Bladder cancer, for instance, is a disease that mainly afflicts middle-aged or elderly people and is mostly of urothelial origin. Although research on age-related changes of long-lived post-mitotic cells such as neurons is rapidly progressing, nothing is known about age-related changes in the urothelium of the urinary bladder, despite all the evidence confirming the important role of oxidative stress in urinary bladder pathology. The purpose of this study was thus to investigate the oxidative status and age-related changes in urothelial cells of the urinary bladder of young (2 months) and aging (20 months) mice by means of various methods. Our results demonstrated that healthy young urothelium possesses a powerful antioxidant defence system that functions as a strong defence barrier against reactive species. In contrast, urothelial cells of aging bladder show significantly decreased total antioxidant capacity and significantly increased levels of lipid peroxides (MDA) and iNOS, markers of oxidative stress. Our study demonstrates for the first time that ultrastructural alterations in mitochondria and accumulation of lipofuscin, known to be one of the aging pigments, can clearly be found in superficial urothelial cells of the urinary bladder in aging mice. Since the presence of lipofuscin in the urothelium has not yet been reported, we applied various methods to confirm our finding. Our results reveal changes in the oxidative status and structural alterations to superficial urothelial cells similar to those of other long-lived post-mitotic cells. © 2013 Perše et al.

Tavcar G.,University of Ljubljana | Katrasnik T.,University of Ljubljana
Journal of Power Sources | Year: 2013

This paper presents an innovative hybrid analytic-numerical approach to modelling species transport in fuel cells suitable for application on the system level. The core principle of this modelling approach is taking 1D numerical model for gas-flow and superimposing onto it a 2D analytic solution for concentration distribution in the plane perpendicular to the gas-flow together giving a 3D information on species concentration in the fuel cell. A hybrid analytic numerical model of a simple geometry isothermal fuel cell is presented and comparatively evaluated by benchmarking it against a professional full 3D CFD simulation tool. This evaluation shows very close agreement with the benchmarking 3D CFD simulation and computational times comparable to 1D models. This computational efficiency originates in the model's analytic nature in the other two dimensions making it suitable for system level application. The paper features an extensive appendix with a comprehensive detailed mathematical derivation of the hybrid analytic-numerical model. © 2013 Elsevier B.V. All rights reserved.

Marinsek M.,University of Ljubljana | Sala M.,Slovenian National Institute of Chemistry | Jancar B.,Jozef Stefan Institute
Journal of Power Sources | Year: 2013

This study investigates several CNT-supported Pd-based catalysts and compares their morphological as well as electrochemical characteristics for formic acid electro-oxidation. Pd/C catalysts are prepared via various impregnation methods, using different reaction media or reducing agents. The average mean particle sizes of the precipitated Pd vary from 2.6 nm to 18.0 nm. It is further shown that the particle size of Pd/C dispersions can be easily controlled by changing the solvent and experimental conditions during the preparation procedure. Measurements of catalytic activity by using cyclic voltammetry reveal strong particle size dependence of the anodic peak current density. The electro-oxidation of formic acid may be kinetically-controlled or diffusion-controlled regarding the Pd morphological characteristics. © 2013 Elsevier B.V. All rights reserved.

Agrez D.,University of Ljubljana
2010 IEEE International Instrumentation and Measurement Technology Conference, I2MTC 2010 - Proceedings | Year: 2010

In this paper, simple algorithms for fast estimation of the amplitude ratio and the phase difference of the sinusoidal signals from two channels with the same frequency are presented. Parameters are calculated from the DFT coefficients around the component peaks. The idea of the systematic error reduction with the weighted amplitude and phase DFT coefficients is used in the comparative measurement procedure. © 2010 IEEE.

Prosen T.,University of Ljubljana
Physical Review Letters | Year: 2011

An exact and explicit ladder-tensor-network ansatz is presented for the nonequilibrium steady state of an anisotropic Heisenberg XXZ spin-1/2 chain which is driven far from equilibrium with a pair of Lindblad operators acting on the edges of the chain only. We show that the steady-state density operator of a finite system of size n is-apart from a normalization constant-a polynomial of degree 2n-2 in the coupling constant. Efficient computation of physical observables is facilitated in terms of a transfer operator reminiscent of a classical Markov process. In the isotropic case we find cosine spin profiles, 1/n2 scaling of the spin current, and long-range correlations in the steady state. This is a fully nonperturbative extension of a recent result. © 2011 American Physical Society.

Znidaric M.,National Autonomous University of Mexico | Znidaric M.,University of Ljubljana | Pineda C.,National Autonomous University of Mexico | Garcia-Mata I.,CONICET | Garcia-Mata I.,Laboratory TANDAR
Physical Review Letters | Year: 2011

The channel induced by a complex system interacting strongly with a qubit is calculated exactly under the assumption of randomness of its eigenvectors. The resulting channel is represented as an isotropic time-dependent oscillation of the Bloch ball, leading to non-Markovian behavior, even in the limit of infinite environments. Two contributions are identified: one due to the density of states and the other due to correlations in the spectrum. Prototype examples, one for chaotic and the other for regular dynamics are explored. © 2011 American Physical Society.

Glucagon-like peptide-1 (GLP-1) based therapy is well established for treating diabetes mellitus type 2. Moreover, GLP-1 receptor agonists influence weight loss, and have potential for treating obesity. GLP-1 receptor agonists should be administered in low doses, together with drugs that potentiate insulin release, to avoid some minor side effects. We have focused on incretin hormones, especially GLP-1 and its analogues. Here we discuss the effect of the third intracellular loop-derived peptide of GLP-1 receptor on intracellular mono-ADP-ribosyltransferase and its role in regulating the receptor. We suggest that this intracellular mono-ADP-ribosyltransferase could constitute a possible novel pharmacological target in the treatment of diabetes mellitus type 2 and obesity.

Blaganje M.,University of Ljubljana | Lukanovic A.,University of Ljubljana
International Journal of Gynecology and Obstetrics | Year: 2012

Objective: To assess the feasibility and safety of ultrasound-guided autologous myoblast injections into the external urethral sphincter followed by electrical stimulation (ES) as a possible 2-step treatment for stress urinary incontinence (SUI). Methods: Autologous myoblasts isolated from a biceps muscle sample were injected under transurethral ultrasound guidance into the external urethral sphincter of 38 female patients. The patients also underwent ES postoperatively to enhance cell integration. Treatment feasibility, as well as possible intraoperative and postoperative complications, was assessed 6 weeks after the injections. Additionally, the effects of the myoblast injections followed by an ES cycle were compared to those of a preoperative ES cycle undergone by the same patients. Results: No serious adverse events or complications were noted and the procedure was well tolerated. Compared with the objective and subjective measurements collected after the preoperative ES cycle, the corresponding measurements obtained 6 weeks postoperatively, after the completion of a second ES cycle, indicated considerable improvement. The results to the stress test were negative for 29 (78.4%) of the patients, 5 (13.5%) considered their SUI cured, and 29 (78.4%) reported improvement. Conclusion: Intrasphincteric autologous myoblast injections followed by ES is minimally invasive and feasible, and safely produced promising initial results. EU Clinical Trials EudraCT No. 2009-012389-30 ClinicalTrials.gov identifier: NCT01355133 © 2012 International Federation of Gynecology and Obstetrics.

Cerkovnik J.,University of Ljubljana | Plesnicar B.,University of Ljubljana
Chemical Reviews | Year: 2013

The article examines recent advances in the chemistry of hydrogen trioxide (HOOOH). Although the IR spectra of the obtained matrices showed some new bands, which were tentatively assigned to HOOOH and HOOOOH, no unambiguous interpretation of the IR spectra could be made at that time. The oxidized resin can be removed by filtration under argon, so that the remaining solutions contained only HOOOH, hydrogen peroxide, and water. However, it appears that considerable amounts of HOOOH are lost in this way. Namely, density functional theory (DFT) calculations revealed that HOOOH forms relatively strongly hydrogen-bonded complexes with 1,2- diphenyldiazene, thus stabilizing the polyoxide. The measured chemical shifts are therefore averaged shift values reflecting the population of various conformational minima. However, the impact of internal rotation of HOOOH on the 17O shift values in polar solvents is probably smaller than in the gas phase because of the specific and nonspecific solvation effects. Hence, rotation averaging presumably has no significant influence on the measured 17O NMR values.

Musevic I.,Jozef Stefan Institute | Musevic I.,University of Ljubljana
Philosophical Transactions of the Royal Society A: Mathematical, Physical and Engineering Sciences | Year: 2013

We review and discuss recent progress in the field of nematic colloids, with an emphasis on possible future applications in photonics. The role of the topology is described, based on experimental manipulations of the topological defects in nematic colloids. The topology of the ordering field in nematics provides the forces between colloidal particles that are unique to these materials. We also discuss recent progress in the new field of active microphotonic devices based on liquid crystals (LCs), where chiral nematicmicrolasers and tuneable nematic microresonators are just two of the recently discovered examples. We conclude that the combination of topology and microphotonic devices based on LCs provides an interesting platform for future progress in the field of LCs. © 2013 The Author(s) Published by the Royal Society. All rights reserved.

Stremfelj J.,Milan Vidmar Electrical Power Research Institute | Agrez D.,University of Ljubljana
IEEE Transactions on Instrumentation and Measurement | Year: 2013

This paper presents algorithms for fast measurement and the nonparametric estimation of the unknown changing frequency, amplitude, and phase difference of the signals from two channels with the same frequency, as well as other power quantities, such as the apparent, the active, and the reactive power. The possibilities for systematic error reduction through use of the interpolated discrete Fourier transform using the Rife-Vincent windows class I (RV-I) are described. RV-I windows are designed for maximization of the window spectrum side-lobes fall-off and owing to their minimal leakage, minimal systematic bias curves can be evaluated as a function of the measurement interval duration expressed in signal cycles. Parameters are calculated from the discrete Fourier transform coefficients around the component peaks by summation to reduce the leakage effects. The optimum for reducing the time of measurement and for reducing systematic errors under non-coherent conditions of sampling real noisy signals could be the estimation with the three cycles window using the three-point interpolation and the RV-I window order 3. © 2013 IEEE.

Hevir N.,University of Ljubljana | Ribic-Pucelj M.,University of Ljubljana | Lanisnik Rizner T.,University of Ljubljana
Molecular and Cellular Endocrinology | Year: 2013

Oxidative metabolism of estrogens was studied in 31 ovarian endometriosis and 29 normal endometrium samples, by qPCR. Expression was monitored for genes encoding five estrogen hydroxylating, five hydroxy (OH)-estrogen conjugating, and three estrogen quinone detoxifying enzymes. CYP1B1, COMT, NQO1, and GSTP1 protein levels were determined using Western blotting and immunohistochemistry staining. Increased expression of CYP1A1, CYP3A7 and COMT, and higher levels of MB-COMT were seen in endometriosis, as compared to normal endometrium. Expression of CYP1B1, CYP3A5, SULT1A1 and NQO2 was unchanged, with comparable CYP1B1 protein levels. Expression of SULT1E1, SULT2B1, UGT2B7, NQO1, and GSTP1 was decreased. Three NQO1 isoforms were detected; NQO1c appears to be endometriosis-specific. Our data indicate a disturbed balance between phase I and II metabolizing enzymes in endometriosis, potentially leading to excessive OH-estrogen and altered ROS formation, and stimulation of proliferation of ectopic endometrium. This is the first report on disturbed expression of estrogen oxidative metabolism genes in ovarian endometriosis. © 2012 Elsevier Ireland Ltd.

Mankoc Borstnik N.S.,University of Ljubljana
Blejske Delavnice iz Fizike - Bled Workshops in Physics | Year: 2010

The theory unifying spin and charges and predicting families, proposed [1,2] as a new way to explain the assumptions of the standard model of the electroweak and colour interactions, predicts at the low energy regime two (by the mixing matrices decoupled) groups of four families. All of them are massless before the two final breaks and identical with respect to the charges and spin. They differ only in the family quantum number. The fourth family of the lower group of four families (three of them known) is predicted to be possibly observed at the LHC or at somewhat higher energies and the stable of the higher four families - the fifth family - is the candidate to constitute the dark matter. In this paper the properties of the fields - spinors, gauge fields and scalar fields - before and after each of the two last successive breaks, leading to the (so far) observed quarks, leptons and gauge fields, are analysed as they follow from the spin-charge-family-theory.

Astrocytes are key players in brain function; they are intimately involved in neuronal signalling processes and their metabolism is tightly coupled to that of neurons. In the present review, we will be concerned with a discussion of aspects of astrocyte metabolism, including energy-generating pathways and amino acid homoeostasis. A discussion of the impact that uptake of neurotransmitter glutamate may have on these pathways is included along with a section on metabolic compartmentation.

Astroglial cells, due to their passive electrical properties, were long considered subservient to neurons and to merely provide the framework and metabolic support of the brain. Although astrocytes do play such structural and housekeeping roles in the brain, these glial cells also contribute to the brain's computational power and behavioural output. These more active functions are endowed by the Ca(2+)-based excitability displayed by astrocytes. An increase in cytosolic Ca(2+) levels in astrocytes can lead to the release of signalling molecules, a process termed gliotransmission, via the process of regulated exocytosis. Dynamic components of astrocytic exocytosis include the vesicular-plasma membrane secretory machinery, as well as the vesicular traffic, which is governed not only by general cytoskeletal elements but also by astrocyte-specific IFs (intermediate filaments). Gliotransmitters released into the ECS (extracellular space) can exert their actions on neighbouring neurons, to modulate synaptic transmission and plasticity, and to affect behaviour by modulating the sleep homoeostat. Besides these novel physiological roles, astrocytic Ca(2+) dynamics, Ca(2+)-dependent gliotransmission and astrocyte-neuron signalling have been also implicated in brain disorders, such as epilepsy. The aim of this review is to highlight the newer findings concerning Ca(2+) signalling in astrocytes and exocytotic gliotransmission. For this we report on Ca(2+) sources and sinks that are necessary and sufficient for regulating the exocytotic release of gliotransmitters and discuss secretory machinery, secretory vesicles and vesicle mobility regulation. Finally, we consider the exocytotic gliotransmission in the modulation of synaptic transmission and plasticity, as well as the astrocytic contribution to sleep behaviour and epilepsy.

Bozic-Mijovski M.,University of Ljubljana
Clinical Chemistry and Laboratory Medicine | Year: 2010

It is now widely accepted that hyperhomocysteinemia (HHC) is a risk factor for thrombophilia. HHC is the result of either impaired enzyme function or a deficiency of vitamin B (folate, B 6, B 12), or both, and can be treated with vitamin supplements. Measuring plasma total homocysteine (tHcy) is included in the routine thrombophilia panel in many laboratories, despite having a limited value to the clinician. Many methods are available for tHcy measurements. High-pressure liquid chromatography (HPLC) with fluorescence detection is a widely used method, but is being replaced by more convenient immuno- or enzyme assays. In this paper a general overview on homocysteine is given, with an emphasis on laboratory methods. Clin Chem Lab Med 2010;48:S89-95. © 2010 by Walter de Gruyter Berlin New York.

Urlep Z.,University of Ljubljana | Rozman D.,University of Ljubljana
Frontiers in Endocrinology | Year: 2013

Circadian aspect of reproduction has gained much attention in recent years. In mammals, it is very important that the timing of greatest sexual motivation is in line with the highest fertility. Peripheral clocks have been found to reside also in reproductive organs, such as the uterus and ovary. The timing signal from the suprachiasmatic nucleus is suggested to be transmitted via hormonal and neural mechanisms, and could thus mediate circadian expression of target genes in these organs. In turn, estrogens from the ovary have been found to signal back to the hypothalamus, completing the feedback loop. In this review we will focus on the interplay between clock and estrogens. Estradiol has been directly linked with expression of Per1 and Per2 in the uterus. CLOCK, on the other hand, has been shown to alter estradiol signaling. We also present the idea that cholesterol could play a vital role in the regulation of reproduction. Cholesterol synthesis itself is circadially regulated and has been found to interfere with steroidogenesis in the ovary on the molecular level. This review presents a systems view on how the interplay between circadian clock, steroidogenesis, and cholesterol synthesis affect various aspects of mammalian reproduction. © 2013 Urlep and Rozman.

Mohler D.,TRIUMF Laboratory Particle and Nuclear Physics | Prelovsek S.,University of Ljubljana | Prelovsek S.,Jozef Stefan Institute | Woloshyn R.M.,TRIUMF Laboratory Particle and Nuclear Physics
Physical Review D - Particles, Fields, Gravitation and Cosmology | Year: 2013

A first exploratory lattice QCD simulation is presented, aimed at extracting the masses and widths of the broad scalar D0*(2400) and the axial D1(2430) charm-light resonances. For that purpose Dπ and D*π scattering are simulated, and the resonance parameters are extracted using a Breit-Wigner fit of the resulting phase shifts. We use a single two-flavor dynamical ensemble with mπ≈266 MeV, a0.124 fm and a rather small volume V=163×32. The resulting D0*(2400) mass is 351±21 MeV above the spin average 14(mD+3mD *), in agreement with the experimental value of 347±29 MeV above. The resulting D0*→Dπ coupling, glat=2.55±0.21 GeV, is close to the experimental value gexpâ¡≤1. 92±0.14 GeV, where g parametrizes the width Γ≡g2p */s. The resonance parameters for the broad D1(2430) are also found close to the experimental values; these are obtained by appealing to the heavy quark limit, where the neighboring resonance D 1(2420) is narrow. The calculated I=1/2 scattering lengths are a 0=0.81±0.14 fm for Dπ and a0=0.81±0.17 fm for D*π scattering. The simulation of the scattering in these channels incorporates quark-antiquark as well as multihadron interpolators, and the distillation method is used for contractions. In addition, the ground and several excited charm-light and charmonium states with various JP are calculated using standard quark-antiquark interpolators. © 2013 American Physical Society.

Copar S.,University of Ljubljana | Zumer S.,University of Ljubljana | Zumer S.,Jozef Stefan Institute
Physical Review Letters | Year: 2011

The conventional topological description given by the fundamental group of nematic order parameter does not adequately explain the entangled defect line structures that have been observed in nematic colloids. We introduce a new topological invariant, the self-linking number, that enables a complete classification of entangled defect line structures in general nematics, even without particles, and demonstrate our formalism using colloidal dimers, for which entangled structures have been previously observed. We also unveil a simple rewiring scheme for the orthogonal crossing of two -1/2 disclinations, based on a tetrahedral rotation of two relevant disclination segments, that allows us to predict possible nematic braids and calculate their self-linking numbers. © 2011 American Physical Society.

Prosen T.,University of Ljubljana
Physical Review Letters | Year: 2011

An explicit matrix product ansatz is presented, in the first two orders in the (weak) coupling parameter, for the nonequilibrium steady state of the homogeneous, nearest neighbor Heisenberg XXZ spin 1/2 chain driven by Lindblad operators which act only at the edges of the chain. The first order of the density operator becomes, in the thermodynamic limit, an exact pseudolocal conservation law and yields-via the Mazur inequality-a rigorous lower bound on the high-temperature spin Drude weight. Such a Mazur bound is a nonvanishing fractal function of the anisotropy parameter Δ for |Δ|<1. © 2011 American Physical Society.

Cotman M.,Slovenian National Institute of Chemistry | Gotvajn A.Z.,University of Ljubljana
Journal of Hazardous Materials | Year: 2010

Our work was focused on investigation of different treatment procedures for the removal of toxic fractions from a landfill leachate, because sometimes the existing treatment in biological sequencing batch reactor (SBR) is not efficient enough, leading to a hazardous environmental impact of the present persistent and toxic compounds. The efficiency of the procedures used was monitored by chemical analyses and two toxicity tests (activated sludge and Vibrio fischeri). The existing SBR (HRT=1.9 days) removed 46-78% of COD and 96-73% of NH4+-N. Experiments were conducted with three landfill leachate samples expressing significant difference in concentrations of pollutants and with low BOD5/COD ratio (0.06/0.01/0.03). The applied methods were air stripping, adsorption to activated carbon and zeolite clinoptilolite and Fenton oxidation. Air stripping at pH 11 was a viable treatment option for the removal of ammonia nitrogen (up to 94%) and reduction of toxicity to microorganisms. In the adsorption experiments in batch system with different concentration of PAC the most effective was the highest addition (50.0gL-1) where 63-92% of COD was removed followed by significant reduction in toxicity to V. fischeri. In the column experiments with clinoptilolite 45/93/100% of NH4+-N as well as 25/32/39% of COD removal was attained. The removal efficiency for metals followed the sequence Cr>Zn>Cd>Ni. The procedure with zeolite was the second most efficient one regarding reduction of toxicity to both organisms. Fenton oxidation at molar ratio Fe2+:H2O2=1.0:10.0 assured 70-85% removal of COD but it only slightly reduced the toxicity. © 2010 Elsevier B.V.

Beges G.,University of Ljubljana
International Journal of Thermophysics | Year: 2011

The objective of this article is presentation of influences when measuring the motor winding temperature rise in the scope of safety testing of electrical appliances, with respect to conformity assessment. The temperature measurement in testing is one of the most defined fields of measurement, but it is very important how the measurement is performed. Standards only describe that the resistance method shall be used for determination of the temperature rise (heating) of the winding. The temperature rise is defined as the average temperature rise of the windings above the ambient (surrounding) temperature, at the specified load of the unit under test. It is not explicitly defined how to approach this measurement when using cooling characteristics of the winding for determination of the temperature rise. Since the extrapolation curve is used, the procedure is also very important to obtain a result as accurate as possible. It is important that measurement results and their associated uncertainties are correctly evaluated, and on that basis, appropriate conclusions of conformity of the product with specifications are made. The resistance method influence on the motor winding temperature rise measurement is a case study in this article. The article focuses on the measurement of the temperature rise of electrical motors used in electrical appliances according to the standard EN 60335-1, clause 11 (2002) (identical as standard IEC 60335-1, 2001). In this article, the influencing parameters are analyzed when measuring the temperature rise of electromotor winding. As a case study, concrete measurements are presented. The optimal time after which the performer has to start measurement of the cooling characteristics is analyzed, since the motors are typically mounted deep into appliances. Especially for a collector motor winding, it takes some time for a performer to be able to connect the measuring instrument to collector's lamellas because this contact has an important influence on extrapolation results. © 2011 Springer Science+Business Media, LLC.

The time-course of product accumulation during an enzyme-catalyzed reaction that conforms to the Michaelis-Menten rate equation is expressed by an explicit closed-form equation in terms of the Lambert W(x) function. Unfortunately, the use of direct solution of the Michaelis-Menten equation is limited, because the W(x) function is not widely available in curve-fitting software. The present commentary suggests an alternative to surmount this difficulty. The Lambert W(x) function can be approximated in terms of the elementary mathematical functions that enable the fitting of particular equations on time-course data of the Michaelis-Menten enzyme reaction by any nonlinear regression computer program. Three different demonstrated approximations of the W(x) with relatively high accuracies are shown here to be appropriate for use when progress curves are analyzed by the direct solution of the integrated Michaelis-Menten equation. The elementary and precise nature of these approximations makes them the most user-friendly open candidates for simple, but operative, kinetic parameter estimations from experimental time-course data. © 2010 Elsevier B.V.

Pavlovcic F.,University of Ljubljana
SPEEDAM 2012 - 21st International Symposium on Power Electronics, Electrical Drives, Automation and Motion | Year: 2012

Electromagnetic interference (EMI) in electric motors with mechanic commutators consists of two phenomena: commutating electromagnetic interference, just due to the changes in motor magnetic energy, and switching electromagnetic interference due to mechanical performance of the commutators as switches. The first phenomenon does not cause commutator wear, but the second causes both: the excessive EMI especially by voltage spikes and discharging arcs, which additionally could reignite drawn arcs, and further on, causing the severe commutator wear. This reignited drawn arc makes progress from the short one to the longer one, being more severe due to material transfer jagging edges and surfaces of commutator bars and brushes. Preventing the overvoltage spikes, and so far the ignition of the discharging arc results, besides reducing EMI, in avoidance of the drawn arc reignition and minimizing also the commutator wear. The paper gives also a method of determining a quenching capacitance value. © 2012 IEEE.

BACKGROUND:: 25%-50% of acute gastroenteritis (AGE) cases remain etiologically undiagnosed. Our main aim was to determine the most appropriate list of enteric pathogens to be included in the daily diagnostics scheme of AGE, ensuring the lowest possible diagnostic gap. METHODS:: 297 children ≤6 years of age, admitted to hospital in Slovenia, October 2011 – October 2012, with AGE, and 88 ≤6 year old healthy children, were included in the study. A broad spectrum of enteric pathogens was targeted with molecular methods, including 8 viruses, 6 bacteria and 2 parasites. RESULTS:: At least one enteric pathogen was detected in 91.2% of cases with AGE and 27.3% of controls. Viruses were the most prevalent (82.5% and 15.9%), followed by bacteria (27.3% and 10.2%) and parasites (3.0% and 1.1%) in cases and controls, respectively. A high proportion (41.8%) of mixed infections was observed in the cases. For cases with undetermined etiology (8.8%), stool samples were analyzed with next generation sequencing and a potential viral pathogen was detected in 17 additional samples (5.8%). CONCLUSIONS:: Our study suggests that tests for rotaviruses, noroviruses genogroup II, adenoviruses 40/41, astroviruses, Campylobacter spp. and Salmonella sp. should be included in the initial diagnostic algorithm, which revealed the etiology in 83.5% of children tested. The use of molecular methods in diagnostics of gastroenteritis is preferable because of their high sensitivity, specificity, fast performance and the possibility of establishing the concentration of the target. The latter may be valuable for assessing the clinical significance of the detected enteric, particularly viral pathogens. Copyright © 2016 Wolters Kluwer Health, Inc. All rights reserved.

Voglar G.E.,RDA Regional Development Agency Celje | Lestan D.,University of Ljubljana
Journal of Hazardous Materials | Year: 2010

In a laboratory study, Portland cement (15%, w/w) was used for solidification/stabilisation (S/S) of Cd, Pb, Zn, Cu, Ni and As contaminated soils from the former industrial site. Soils formed solid monoliths with cement. S/S effectiveness was assessed by measuring the mechanical strength of the monoliths, concentrations of metals in deionised water and TCLP (toxicity characteristic leaching procedure) soil extracts, and mass transfer of metals. Concentrations of Cd, Pb, Zn and Ni in water extracts from S/S soils generally decreased, concentrations of As remained unchanged, while concentrations of Cu increased. Concentrations of Cd, Pb, Zn and Ni in the TCLP extracts from S/S soils were lower than from original soils. Cu extractability was lower in most soil samples, while the extractability of As from S/S soils increased. Overall, the concentration of metals in deionised water and TCLP solution, obtained after extraction of the S/S soils, was below the regulatory limits. S/S greatly reduced the mass transfer of Cd (up to 83-times), Pb (up to 13.7-times) and Zn (up to 294-times). Mass transfer of Ni and As was generally also reduced, while that of Cu increased in some S/S soils. Based on the findings of mass-transfer mechanism analysis the predominant mechanism of release was surface wash-off of metals otherwise physically encapsulated within the cementous soil matrix. © 2010 Elsevier B.V.

Bohinc K.,University of Ljubljana
Pure and Applied Chemistry | Year: 2013

A short review of recent theoretical advances in studies of the interaction between highly charged systems is presented. Such a system could not be described by the mean field theory. More advanced methods have to be used in order to introduce the correlations between highly charged particles. In this work I focus on the system of highly charged surfaces, separated by a solution of molecules with spatially distributed charge. Two different representations of the molecular shape will be considered: rod-like and spherical. The system will be theoretically described by the density functional theory. For sufficiently long molecules and large surface charge densities, an attractive force between like-charged surfaces arises due to the spatially distributed charges within the molecules. The added salt has influence on the condition for the attractive force between like-charged surfaces. The theoretical results will be compared with Monte Carlo (MC) simulations. Recent measurements with multivalent rigid rod-like particles will be discussed. © 2012 IUPAC.

Petek M.,University of Ljubljana
OCLC Systems and Services | Year: 2012

Purpose: Images can be seen in a different way by different users. The purpose of this paper is to examine how users describe images and to ascertain whether differences exist between users and librarians in creating metadata on images. Design/methodology/approach: The paper compares metadata on digital images generated by users to metadata generated by librarians. A sample of images taken from Digital Library of Slovenia and Flickr is presented to students to assign tags. The tags are grouped into categories and classes of attributes and compared to keywords added by Slovene librarians and to tags created by Flickr visitors. Findings: The number of assigned tags differs greatly among survey participants, librarians and Flickr users, the participants being the most productive. A majority of tags reflect perceptual attributes and tagging is mostly done for personal benefit. The matching rate for all images is 41.4 percent; matching is a little higher with the Flickr images. Practical implications: Social tagging can be used to develop control vocabularies reflecting users' language and to provide access to digital images. Originality/value: The paper presents quantitative data on image attributes used by users in describing images. © Emerald Group Publishing Limited.

Terwilliger P.,University of Wisconsin - Madison | Zitnik A.,University of Ljubljana
Journal of Combinatorial Theory. Series A | Year: 2014

Let C denote the field of complex numbers, and fix a nonzero q∈C such that q4 ≠ 1. Define a C-algebra δq by generators and relations in the following way. The generators are A, B, C. The relations assert that each ofA+qBC-q-1CBq2-q-2,B+qCA-q-1ACq2-q-2,C+qAB-q-1BAq2-q-2 is central in δq. The algebra δq is called the universal Askey-Wilson algebra. Let denote a distance-regular graph that has q-Racah type. Fix a vertex x of and let T = T(x) denote the corresponding subconstituent algebra. In this paper we discuss a relationship between δq and T. Assuming that every irreducible T-module is thin, we display a surjective C-algebra homomorphism δq→T. This gives a δq action on the standard module of T. © 2014 Elsevier Inc.

Virant-Klun I.,University of Ljubljana
Stem Cells and Development | Year: 2016

It has been suggested that hematopoietic stem/progenitor cells (HSPCs) could become specified from a population of migrating primordial germ cells (PGCs), precursors of gametes, during embryogenesis. Some recent experimental data demonstrated that the cell population that is usually considered to be PGCs, moving toward the gonadal ridges of an embryo, contains a subset of cells coexpressing several germ cell and hematopoietic markers and possessing hematopoietic activity. Experimental data showed that bone morphogenetic protein 4 (BMP4) generates PGCs from mouse bone marrow-derived pluripotent stem cells. Interestingly, functional reproductive hormone receptors have been identified in HSPCs, thus indicating their potential role in reproductive function. Several reports have demonstrated fertility restoration and germ cell generation after bone marrow transplantation in both animal models and humans. A potential link between HSPCs and germinal lineage might be represented by very small embryonic-like stem cells (VSELs), which have been found in adult human bone marrow, peripheral blood, and umbilical cord blood, express a specific pattern of pluripotency, germinal lineage, and hematopoiesis, and are proposed to persist in adult tissues and organs from the embryonic period of life. Stem cell populations, similar to VSELs, expressing several genes related to pluripotency and germinal lineage, especially to PGCs, have been discovered in adult human reproductive organs, ovaries and testicles, and were related to primitive germ cell-like cell development in vitro, thus supporting the idea of VSELs as a potential link between germinal lineage and hematopoiesis. © 2016 Mary Ann Liebert, Inc.

Ster M.P.,University of Ljubljana
Croatian Medical Journal | Year: 2011

Aim: To determine the prevalence of psychotropic medication prescribing in elderly nursing home residents in Slovenia and to explore the residents', physicians', and nursing home characteristics associated with prescribing. Methods: In a cross-sectional study, we collected the data for 2040 nursing home residents aged 65 years and older in 12 nursing homes in Slovenia between September 25 and November 30, 2006. Prescribed medications lists were retrieved from patients' medical records. Psychotropic medications were coded according to Anatomical Therapeutic Chemical Classification 2005, which we adjusted for the purposes of the study. Multivariate logistic regression analysis was performed to determine the residents', physicians', and nursing home characteristics associated with prescribing. Results: Residents were from 65 to 104 years old (median, 83 years) and 1606 (79%) of them were female. A total of 970 (48%) residents had dementia and 466 had depression (23%). In 1492 (73%) residents, at least one psychotropic medication was prescribed. Nine hundred sixty residents were prescribed hypnotics and sedatives (47%), 572 (28%) antipsychotics, 460 (23%) antidepressants, and 432 (21%) anxiolytics. Residents' characteristics associated with psychotropic medication use were female sex (odds ratio [OR], 1.36; 95% confidence interval [CI], 1.03-1.80), age (OR, 0.97; 95% CI, 0.95-0.98), permanent restlessness (OR, 2.54; 95% CI, 1.71-3.78), dementia (OR, 1.76; 95% CI, 1.33-2.34), depression (OR, 5.51; 95% CI, 3.50-7.58), and the number of prescribed medications (OR, 1.29; 95% CI, 1.23-1.35). Of physicians' characteristics (sex, age, specialization in general practice, years of working experiences as a general practitioner, and years of experiences working in a nursing home), male sex was associated with psychotropic medication prescribing (OR, 1.80; 95% CI, 1.17-2.76). Conclusion: Frequency of psychotropic medication prescribing in elderly nursing home residents in Slovenia is high and is comparable to Western European countries. Our next step should be optimizing the prescribing in patients with the highest prescription rate.

Pozar T.,University of Ljubljana | Babnik A.,University of Ljubljana | Mozina J.,University of Ljubljana
Optics Express | Year: 2015

During the interaction of a laser pulse with the surface of a solid object, the object always gains momentum. The delivered force impulse is manifested as propulsion. Initially, the motion of the object is composed of elastic waves that carry and redistribute the acquired momentum as they propagate and reflect within the solid. Even though only ablation-and lightpressure-induced mechanical waves are involved in propulsion, they are always accompanied by the ubiquitous thermoelastic waves. This paper describes 1D elastodynamics of pulsed optical manipulation and presents two diametrical experimental observations of elastic waves generated in the confined ablation and in the radiation pressure regime. © 2015 OSA.

Bronner G.,Sexual Medicine Center | Vodusek D.B.,University of Ljubljana
Therapeutic Advances in Neurological Disorders | Year: 2011

Nonmotor symptoms, among them sexual dysfunction, are common and underrecognized in patients with Parkinson disease; they play a major role in the deterioration of quality of life of patients and their partners. Loss of desire and dissatisfaction with their sexual life is encountered in both genders. Hypersexuality (HS), erectile dysfunction and problems with ejaculation are found in male patients, and loss of lubrication and involuntary urination during sex are found in female patients. Tremor, hypomimia, muscle rigidity, bradykinesia, 'clumsiness' in fine motor control, dyskinesias, hypersalivation and sweating may interfere with sexual function. Optimal dopaminergic treatment should facilitate sexual encounters of the couple. Appropriate counselling diminishes some of the problems (reluctance to engage in sex, problems with ejaculation, lubrication and urinary incontinence). Treatment of erectile dysfunction with sildenafil and apomorphine is evidence based. HS or compulsive sexual behaviour are side effects of dopaminergic therapy, particularly by dopaminergic agonists, and should be treated primarily by diminishing their dose. Neurologists should actively investigate sexual dysfunction in their Parkinsonian patients and offer treatment, optimally within a multidisciplinary team, where a dedicated professional would deal with sexual counselling. © SAGE Publications 2011.

Zupanic Pajnic I.,University of Ljubljana | Gornjak Pogorelc B.,University of Ljubljana | Balazic J.,University of Ljubljana
International Journal of Legal Medicine | Year: 2010

This paper describes molecular genetic identification of one third of the skeletal remains of 88 victims of postwar (June 1945) killings found in the Konfin I mass grave in Slovenia. Living relatives were traced for 36 victims. We analyzed 84 right femurs and compared their genetic profiles to the genetic material of living relatives. We cleaned the bones, removed surface contamination, and ground the bones into powder. Prior to DNA isolation using Biorobot EZ1 (Qiagen), the powder was decalcified. The nuclear DNA of the samples was quantified using the real-time polymerase chain reaction method. We extracted 0.8 to 100 ng DNA/g of bone powder from 82 bones. Autosomal genetic profiles and Y-chromosome haplotypes were obtained from 98% of the bones, and mitochondrial DNA (mtDNA) haplotypes from 95% of the bones for the HVI region and from 98% of the bones for the HVII region. Genetic profiles of the nuclear and mtDNA were determined for reference persons. For traceability in the event of contamination, we created an elimination database including genetic profiles of the nuclear and mtDNA of all persons that had been in contact with the skeletal remains. When comparing genetic profiles, we matched 28 of the 84 bones analyzed with living relatives (brothers, sisters, sons, daughters, nephews, or cousins). The statistical analyses showed a high confidence of correct identification for all 28 victims in the Konfin I mass grave (posterior probability ranged from 99.9% to more than 99.999999%). © 2010 The Author(s).

Kreft M.,University of Ljubljana
Nutrition Research Reviews | Year: 2016

Buckwheat (Fagopyrum esculentum Moench, F. tataricum Gaertner) groats and flour have been established globally as nutritional foods because of their high levels of proteins, polyphenols and minerals. In some regions, buckwheat herb is used as a functional food. In the present study, reports of in vitro studies, preclinical and clinical trials dealing with the effect of buckwheat and its metabolites were reviewed. There are numerous reports of potential health benefits of consuming buckwheat, which may be in the form of food, dietary supplements, home remedies or possibly pharmaceutical drugs; however, adverse effects, including those resulting from contamination, must be considered. There are reports of antioxidative activity of buckwheat, which contains high levels of rutin and quercetin. On the other hand, both cytotoxic and antigenotoxic effects have been shown. Reduction of hyperlipidaemia, reduction of blood pressure and improved weight regulation have been suggested. Consuming buckwheat may have a beneficial effect on diabetes, since lower postprandial blood glucose and insulin response have been reported. In addition, buckwheat metabolites, such as rutin, may have intrinsic protective effects in preserving insulin signalling. Rutin has also been suggested to have potential therapeutic applications for the treatment of Alzheimer’s disease. The literature indicates that buckwheat is safe to consume and may have various beneficial effects on human health. Copyright © The Authors 2016

Jelusic M.,University of Ljubljana | Lestan D.,University of Ljubljana
Science of the Total Environment | Year: 2014

We applied a multi-level approach assessing the quality, toxicity and functioning of Pb, Zn and Cd contaminated/remediated soil from a vegetable garden in Meza Valley, Slovenia. Contaminated soil was extracted with EDTA and placed into field experimental plots equipped with lysimeters. Soil properties were assessed by standard pedological analysis. Fractionation and leachability of toxic metals were analyzed by sequential extraction and TCLP and metal bioaccessibility by UBM tests. Soil respiration and enzyme activities were measured as indicators of soil functioning. Remediation reduced the metal burden by 80, 28 and 72% for Pb, Zn and Cd respectively, with a limited impact on soil pedology. Toxic metals associated with labile soil fractions were largely removed. No shifts between labile and residual fractions were observed during the seven months of the experiment. Initial metal leaching measured through lysimeters eventually ceased. However, remediation significantly diminished potential soil enzyme activity and no trends were observed of the remediated soil recovering its biological properties. Soil washing successfully removed available forms of Pb, Zn and Cd and thus lowered the human and environmental hazards of the remediated soil; however, remediation also extracted the trace elements essential for soil biota. In addition to reduced water holding capacity, soil health was not completely restored. © 2013 Elsevier B.V.

Menard A.,University of Ljubljana | Drobne D.,University of Ljubljana | Drobne D.,Jozef Stefan Institute | Jemec A.,Slovenian National Institute of Chemistry
Environmental Pollution | Year: 2011

This report presents an exhaustive literature review of data on the effect of nanoparticulate TiO2 on algae, higher plants, aquatic and terrestrial invertebrates and freshwater fish. The aim, to identify the biologically important characteristics of the nanoparticles that have most biological significance, was unsuccessful, no discernable correlation between primary particle size and toxic effect being apparent. Secondary particle size and particle surface area may be relevant to biological potential of nanoparticles, but insufficient confirmatory data exist. The nanotoxicity data from thirteen studies fail to reveal the characteristics actually responsible for their biological reactivity because reported nanotoxicity studies rarely carry information on the physicochemical characteristics of the nanoparticles tested. A number of practical measures are suggested which should support the generation of reliable QSAR models and so overcome this data inadequacy. © 2010 Elsevier Ltd. All rights reserved.

Maver J.,University of Ljubljana
IEEE Transactions on Pattern Analysis and Machine Intelligence | Year: 2010

In this work, we present a new approach to interest point detection. Different types of features in images are detected by using a common computational concept. The proposed approach considers the total variability of local regions. The total sum of squares computed on the intensity values of a local circular region is divided into three components: between-circumferences sum of squares, between-radii sum of squares, and the remainder. These three components normalized by the total sum of squares represent three new saliency measures, namely, radial, tangential, and residual. The saliency measures are computed for regions with different radii and scale spaces are built in this way. Local extrema in scale space of each of the saliency measures are located. They represent features with complementary image properties: blob-like features, corner-like features, and highly textured points. Results obtained on image sets of different object classes and image sets under different types of photometric and geometric transformations show high robustness of the method to intraclass variations as well as to different photometric transformations and moderate geometric transformations and compare favorably with the results obtained by the leading interest point detectors from the literature. The proposed approach gives a rich set of highly distinctive local regions that can be used for object recognition and image matching. © 2010 IEEE.

The commodity-form played an important, if often overlooked, role in the studies of capitalism. Processes of transforming literally anything into a privatized form of (fictitious) commodity that is exchanged in the circulation process are of fundamental importance for the rise and reproduction of capitalism. At the same time the commodity, as the "cell-form of capitalism", has played a crucial role throughout Marx's oeuvre. The central aim of the paper is to demonstrate how the commodity-form develops in his works (both as a part of his "global" argument and in the context of historical changes) and what role it plays in some of the key works of critical theory. Furthermore, the aim is to show how this topic was approached in critical communication studies and has been analysed in the political economy of communication. The latter is done principally through a reappraisal of the "blind spot debate" initiated by Dallas W. Smythe and the audience commodity thesis, in which it was raised. This long-lasting debate, which at least indirectly continues to date, can be seen as an invaluable source for practices and ideas connected to both Marxian-inspired critical communication studies and to a serious analysis of the continuing commodification of different spheres of society and its increasing pervasiveness in contemporary life. In the last section, these findings are connected to some of the recent neo-Marxist approaches, especially to the findings of the authors coming from the autonomist (post-operaist) movement. Insights into this intellectual strand can provide an understanding of the ongoing commodification processes, while also offering possibilities of convergence with Smythe's approach.

Martins C.,New University of Lisbon | Oliveira T.,New University of Lisbon | Popovic A.,New University of Lisbon | Popovic A.,University of Ljubljana
International Journal of Information Management | Year: 2014

Understanding the main determinants of Internet banking adoption is important for banks and users; our understanding of the role of users' perceived risk in Internet banking adoption is limited. In response, we develop a conceptual model that combines unified theory of acceptance and use of technology (UTAUT) with perceived risk to explain behaviour intention and usage behaviour of Internet banking. To test the conceptual model we collected data from Portugal (249 valid cases). Our results support some relationships of UTAUT, such as performance expectancy, effort expectancy, and social influence, and also the role of risk as a stronger predictor of intention. To explain usage behaviour of Internet banking the most important factor is behavioural intention to use Internet banking. © 2013 Elsevier Ltd. All rights reserved.

Baumert M.,University of Adelaide | Starc V.,University of Ljubljana | Porta A.,University of Milan
PLoS ONE | Year: 2012

Increased beat-to-beat variability in the QT interval (QTV) of ECG has been associated with increased risk for sudden cardiac death, but its measurement is technically challenging and currently not standardized. The aim of this study was to investigate the performance of commonly used beat-to-beat QT interval measurement algorithms. Three different methods (conventional, template stretching and template time shifting) were subjected to simulated data featuring typical ECG recording issues (broadband noise, baseline wander, amplitude modulation) and real short-term ECG of patients before and after infusion of sotalol, a QT interval prolonging drug. Among the three algorithms, the conventional algorithm was most susceptible to noise whereas the template time shifting algorithm showed superior overall performance on simulated and real ECG. None of the algorithms was able to detect increased beat-to-beat QT interval variability after sotalol infusion despite marked prolongation of the average QT interval. The QTV estimates of all three algorithms were inversely correlated with the amplitude of the T wave. In conclusion, template matching algorithms, in particular the time shifting algorithm, are recommended for beat-to-beat variability measurement of QT interval in body surface ECG. Recording noise, T wave amplitude and the beat-rejection strategy are important factors of QTV measurement and require further investigation. © 2012 Baumert et al.

Becirevic D.,University Paris - Sud | Fajfer S.,University Paris - Sud | Kosnik N.,University of Ljubljana | Kosnik N.,Jozef Stefan Institute
Physical Review D - Particles, Fields, Gravitation and Cosmology | Year: 2015

We explore a scenario of new physics entering the description of B→K(∗)μμ decay through couplings to the operators O9,10′, satisfying C9′=-C10′. From the current data on B(Bs→μμ) and B(B→Kμμ)[15,22]GeV2, we obtain constraints on ReC10′ and ImC10′ which we then assume to be lepton specific, and find RK=B(B→Kμμ)/B(B→Kμμ)[1,6]GeV2=0.88(8), consistent with the recent value measured at the LHCb. A specific realization of this scenario is the one with a scalar leptoquark state Δ, in which C10′ is related to the mass of Δ and its Yukawa couplings. We then show that this scenario does not make any significant impact on Bs-B¯s mixing amplitude or on B(B→Kνν¯). Instead, it can modify RK∗=B(B→K∗μμ)/B(B→K∗μμ)[1,6]GeV2, which will soon be experimentally measured, and we find it to be RK∗=1.11(8), while RK∗/RK=1.27(19). A similar ratio of forward-backward asymmetries also becomes lower than in the Standard Model. © 2015 American Physical Society.

Takezoe H.,Tokyo Institute of Technology | Gorecka E.,University of Warsaw | Cepic M.,Jozef Stefan Institute | Cepic M.,University of Ljubljana
Reviews of Modern Physics | Year: 2010

This paper reviews nearly 20 years of research related to antiferroelectric liquid crystals and gives a short overview of possible applications. "Antiferroelectric liquid crystals" is the common name for smectic liquid crystals formed of chiral elongated molecules that exhibit a number of smectic (Sm) tilted structures with variation of the strong-tilt azimuthal direction from layer to layer (i.e., nonsynclinic structures). The phases have varying crystallographic unit periodicity from a few (Sm Cα*), four (Sm C FI2 *), three (Sm C FI1 *), and two (Sm CA*) smectic layers and all of the phases possess liquidlike order inside the layer. The review describes the discovery of these phases and various methods used for their identification and to determine their structures and their properties. A theoretical description of these systems is also given; one of the models-the discrete phenomenological model-of antiferroelectric liquid crystals is discussed in detail as this model allows for an explanation of phase structures and observed phase sequences under changes of temperature or external fields that is most consistent with experimental results. © 2010 The American Physical Society.

Luzar B.,University of Ljubljana | Calonje E.,St Thomass Hospital
Archives of Pathology and Laboratory Medicine | Year: 2011

Context.-Deep penetrating nevus is a distinctive melanocytic lesion that may simulate melanoma both clinically and histologically. Objective.-To review clinical and histologic features of deep penetrating nevi and discuss their differential diagnosis, especially regarding melanoma. Data Sources.-The literature on deep penetrating nevi is reviewed and supplemented by our experiences with deep penetrating nevi. Conclusions.-One or more disturbing histologic features may frequently be found in deep penetrating nevi, including asymmetry, plump but fairly regular nests of melanocytes in the dermis, cytologic atypia with some nuclear pleomorphism, a small to medium-sized eosinophilic nucleolus, absence of maturation, occasional presence of normal dermal mitoses, and a patchy mononuclear inflammatory cell infiltrate. Although unusual, such histologic features should not be regarded as a sign of malignancy in deep penetrating nevi.

Podnar S.,University of Ljubljana | Harlander M.,University of Ljubljana
Muscle and Nerve | Year: 2013

Introduction: The most common etiology of hypercapnic respiratory failure is chronic obstructive pulmonary disease (COPD). However, the differential diagnosis also includes neuromuscular disorders. We studied the specificity of reduced amplitude phrenic nerve compound motor action potential (CMAP) to diagnose neuromuscular disorders. Methods: A group of patients with advanced COPD were recruited prospectively and compared with controls. Phrenic nerve CMAPs were measured bilaterally using supraclavicular surface stimulation and bipolar recording (G1: 5 cm above the xiphoid; G2: 16 cm from G1). Results: A group of 20 patients (15 men) and a group of 29 controls (15 men) were included. Phrenic nerve CMAPs of patients with COPD had significantly longer latency and higher amplitude. Conclusion: Our study demonstrates that patients with hypercapnic respiratory failure and reduced phrenic nerve CMAP amplitude most probably have a neuromuscular disorder affecting the diaphragm and not COPD or another lung disorder. © 2012 Wiley Periodicals, Inc.

Gustin S.,Farme Ihan D.d. | Marinsek-Logar R.,University of Ljubljana
Process Safety and Environmental Protection | Year: 2011

A stable continuous stripping of ammonia from the anaerobic wastewater treatment plant effluent was obtained in the ammonia stripping bench plant. The effects of temperature, amount of air and pH level on the removal of ammonium from the effluent were examined in the experiments. The operating parameters in the trials were chosen in respect of the economically feasible operating conditions in a biogas plant. The results of ammonium removal were compared with theoretically calculated values of free ammonia in these conditions. Ammonia stripping bench plant continuously removed up to 92.8% of ammonium and 88.3% of total nitrogen from the anaerobic digestion effluent. High pH had the most significant effect on stripping, causing the change of the ammonia/ammonium ratio in favour of ammonia. The second important factor was the amount of air passing through the stripping bench plant promoting the transition of ammonia from the liquid phase to the gas phase. The temperature within the examined range had the least significant effect on ammonia stripping. Continuous stripping of nitrogen from the anaerobic digestion effluent could considerably reduce the area required for the application of nitrogen-rich digestate after the biogas production and enable the treatment of the anaerobically digested effluent in the wastewater treatment plant. © 2010 The Institution of Chemical Engineers. Published by Elsevier B.V. All rights reserved.

Grgic G.,Metrology Institute of the Republic of Slovenia | Pusnik I.,University of Ljubljana
International Journal of Thermophysics | Year: 2011

A thermal imager with a microbolometer focal plane array (FPA) detector which does not require cooling is a relatively new type of instrument. With increasing use of thermal imagers for absolute temperature measurements, there is also an increasing need for their calibration. Five thermal imagers from three manufacturers were evaluated to identify parameters which affect their performance for accurate temperature measurements. Evaluation methods and measurements of parameters such as accuracy, temperature resolution, drift between internal calibration, non-uniformity, size-of-source effect, and distance effect are discussed. Based on the results, it is indicated which parameters should be evaluated in the calibration procedure as well as the uncertainty budget. The suitability of a blackbody for calibration was also addressed, especially in terms of dimensions related to the field of view of a thermal imager at the minimum focal distance. © 2011 Springer Science+Business Media, LLC.

Site effects studies using microtremor free-field measurements were performed recently in five Slovenian towns characterized by increased seismic hazard to determine resonance frequency of soft sediments. In this study, microtremor investigations were extended to the measurements inside buildings to determine their fundamental frequencies and to assess the possible occurrence of soil-structure resonance. Measurements were performed in 66 buildings, and by spectral analysis, it was possible to determine reliably fundamental frequencies (longitudinal and transverse) for 58 buildings. Residential masonry houses with two or three floors prevail, but some buildings of up to six-floor height were also surveyed. Microtremor measurements have proved to be an effective tool for assessment of fundamental frequencies of buildings. Such experimental approach is very valuable, as analytical seismic evaluation of an existing building is usually very difficult. Statistical analysis of the fundamental frequency versus number of floors (height) was performed to generalize identification of potential soil-structure resonance. The difference in average fundamental frequency is very clear between buildings with two and three floors. The average value of both horizontal components for two-floor buildings is 9.11 ± 1.94 Hz, and for three-floor buildings, 7.03 ± 1.46 Hz. On the other hand, the difference in frequencies between three- and four-floor buildings (average for later is 6.52 ± 0.80 Hz) is very small. The average fundamental frequencies for five- and six-floor buildings are lower, 4.62 ± 0.64 Hz and 5.30 ± 0.70 Hz, respectively, with no statistically significant difference between both types. Most Slovenian towns are located in shallow sedimentary basins where the free-field soft covers frequencies are in the range 2-20 Hz. On the other hand, houses with two and three floors represent the large majority of the building stock. To assess the possible occurrence of soil-structure resonance in general, an average fundamental frequency ± one standard deviation interval is obtained for these two building heights, which gives the range 5.6-11.1 Hz. The free-field data show that this frequency range occupies from 22 % of the surveyed area in the Kobarid basin to up to 59 % in the Bovec basin and is in between for other three basins. This leads to the conclusion that the possible occurrence of soil-structure resonance is a serious issue for typical geological situations, in which towns are located. © 2012 Springer Science+Business Media B.V.

Rizner T.L.,University of Ljubljana
Molecular and Cellular Endocrinology | Year: 2013

Endometrial cancer is the most common gynecological malignancy in the developed World. Based on their histopathology, clinical manifestation, and epidemiology, the majority of endometrial cancer cases can be divided into two groups: the more prevalent type 1 which is associated with unopposed estrogen exposure; and the less common type 2, which is usually not associated with hyper-estrogenic factors. This manuscript overviews the published data on the expression of genes encoding the estrogen biosynthetic enzymes, the phase I and phase II estrogen metabolic enzymes, and the estrogen receptors in endometrial cancer, at the mRNA, protein and enzyme activity levels. The potential role of altered expression of these enzymes and receptors in cancerous versus control endometrial tissue, and the implication of estrogens in tumor initiation and promotion, are discussed. Finally, based on the published data, a model of estrogen metabolism and actions is proposed for pre-cancerous and cancerous endometrial tissue, and the role of the estrogens in the progression of endometrial cancer from endometrial hyperplasia is suggested. © 2013 Elsevier Ireland Ltd.

Mavcic B.,University of Ljubljana | Antolic V.,University of Ljubljana
International Orthopaedics | Year: 2012

The aim of this paper is to review recent experimental and clinical publications on bone biology with respect to the optimal mechanical environment in the healing process of fractures and osteotomies. The basic postulates of bone fracture healing include static bone compression and immobilisation/ fixation for three weeks and intermittent dynamic loading treatment afterwards. The optimal mechanical strain should be in the range of 100-2,000 microstrain, depending on the frequency of the strain application, type of bone and location in the bone, age and hormonal status. Higher frequency of mechanical strain application or larger number of repetition cycles result in increased bone mass at the healing fracture site, but only up to a certain limit, values beyond which no additional benefit is observed. Strain application and transition period from non-load-bearing to full load-bearing can be modified by implants allowing dynamisation of compression and generating strains at the fracture healing site in a controlled manner. © 2012 Springer-Verlag.

Kocjan B.J.,University of Ljubljana
The Journal of infectious diseases | Year: 2013

Seventy initial and 125 follow-up tissue specimens of laryngeal papillomas, obtained from 70 patients who had had recurrent respiratory papillomatosis for from 1-22 years, were investigated for the presence of human papillomavirus (HPV) DNA and HPV E5a, LCR and/or full-length genomic variants. HPV-6 was found in 130/195, HPV-11 in 63/195, and HPV-6/HPV-11 in 2/195 samples. Within 67/70 (95.7%) patients, all follow-up HPV isolates genetically matched completely initial HPV isolate over the highly variable parts of the genome or over the entire genome. Frequent recurrence of laryngeal papillomas is a consequence of long-term persistence of the identical initial HPV genomic variant.

Selih J.,University of Ljubljana
Journal of Civil Engineering and Management | Year: 2010

Selection of de-icing agent applied to the road surfaces can crucially affect the winter driving conditions as well as the deterioration of materials employed in the road structures in cold climates. In particular, concrete as one of the main construction load bearing materials can be affected. Road managers should therefore base their decisions regarding the selection of de-icing agent not only on data regarding their defrosting potential but also on data related to deterioration rates of materials built in the road infrastructure system. The paper presents the results of a study where the influence of different types of de-icing salts upon concrete performance was assessed in laboratory conditions. The theoretical background of freezing and thawing in the presence of de-icing salts in concrete is summarized. Salt scaling tests were performed using 3 selected de-icing salts on 3 different types of concrete. The mass scaled off the surface was weighed after every 5 freeze-thaw cycles. The results obtained show that a CaCl2 solution has the most destructive effect upon concrete performance, regardless of the type of concrete. Deterioration was the least when a MgCl2 solution was applied to the concrete surface.

Prodan I.,University of Ljubljana | Drnovsek M.,University of Ljubljana
Technovation | Year: 2010

Policy makers are increasingly recognizing the catalytic role of academics' spin-off companies in a national economy, which derives from their innovativeness that result in new value generation, and job creation. Although research on academics' spin-off companies has been increasing, knowledge gaps exist as to the specific determinants and processes that characterize the emergence of academics' entrepreneurial intentions that lead them to spin off companies. This research aims to fill this gap. Drawing from psychological and entrepreneurship research on intentionality, the authors propose a conceptual model of academics' entrepreneurial intentions. They empirically test the model using structural equation modeling and a robust data set collected in two European academic settings to guide future research on this important topic. © 2010 Elsevier Ltd. All rights reserved.

Tavcer P.F.,University of Ljubljana
Biocatalysis and Biotransformation | Year: 2012

Glucose oxidase enzymes were used to produce hydrogen peroxide from glucose and oxygen in aqueous solutions. Different working conditions, that is, temperature, aeration with liquefied air, presence of cotton fibre and time of enzyme activity, were tested in order to obtain a solution with the highest possible concentration of hydrogen peroxide. The hydrogen peroxide produced was transformed into different peracids which could bleach the cotton fabric under mild conditions, at a pH between 7 and 8 and at a temperature of around 60°C. The conversion or activation of hydrogen peroxide was conducted with the bleach activators TAED, NOBS and TBBC. The concentrations of hydrogen peroxide and peracids in the solutions were measured with sodium thiosulphate titrations. The results indicated that the formation of hydrogen peroxide with glucose oxidase was effective under optimal conditions, which are 50°C, pH 4.6 and aeration. Convenient activators for the conversion of hydrogen peroxide into peracids were TAED and TBBC, which enabled attainment of a relatively high degree of whiteness at pH 7.5 and temperature 50°C. Using the activator NOBS under these conditions did not provide enough peracid to markedly improve whiteness. © 2012 Informa UK, Ltd.

Bratina N.,University of Ljubljana
Pediatric endocrinology reviews : PER | Year: 2010

The use of insulin pump and continuous glucose monitoring (CGM) therapies in children and adolescents with type 1 diabetes (T1DM) has increased over the last 10 years, including the group of children <7 years of age. When these young children use pumps and CGM, their families, teachers, school nurses and professional caregivers (who take the place of school nurses in many countries) in preschools, kindergartens and primary schools need to give them special attention since they depend completely on their help in succeeding with diabetes management. Written individualized diabetesrelated health-care plans should be agreed upon between parents, school nurses, professional caregivers and teachers, and the diabetes healthcare team. A structured educational program should be provided for preschools, kindergartens and primary schools that includes information about and practical training for the use of these new diabetes-related technologies.

Battelino T.,University of Ljubljana
Pediatric endocrinology reviews : PER | Year: 2010

Several recent randomized controlled trials offer firm evidence supporting the efficacy and safety of real-time continuous glucose monitoring (RT-CGM) in type 1 diabetes mellitus (T1DM). Improved metabolic control with significant lowering of glycated hemoglobin (A1C) along with other parameters of glycemia, and without a concomitant increase in hypoglycemia, has been demonstrated. However, poor compliance in adolescents has been a limiting factor in that age group. The potential of RT-CGM of reducing hypoglycemia in well-controlled individuals with T1DM is anticipated but remains to be confirmed. The current high cost of this technology may limit clinical experience in routine clinical settings.

Skulj D.,University of Ljubljana
International Journal of Approximate Reasoning | Year: 2011

A new approach to constructing generalised probabilities is proposed. It is based on the models using lower and upper previsions, or equivalently, convex sets of probability measures. Our approach uses sets of Markov operators in the role of rules preserving desirability of gambles. The main motivation being the operators of conditional expectations which are usually assumed to reduce riskiness of gambles. Imprecise probability models are then obtained in the ways to be consistent with those desirability preserving rules. The consistency criteria are based on the existing interpretations of models using imprecise probabilities. The classical models based on lower and upper previsions are shown to be a special class of the generalised models. Further, we generalise some standard extension procedures, including the marginal extension and independent products, which can be defined independently of the existing procedures known for standard models. © 2011 Elsevier Ltd. All rights reserved.

Mierzejewski M.,University of Silesia | Prelovsek P.,University of Ljubljana | Prelovsek P.,Jozef Stefan Institute | Prosen T.,University of Ljubljana
Physical Review Letters | Year: 2014

We establish a relation between two hallmarks of integrable systems: the relaxation towards the generalized Gibbs ensemble (GGE) and the dissipationless charge transport. We show that the former one is possible only if the so-called Mazur bound on the charge stiffness is saturated by local conserved quantities. As an example we show how a non-GGE steady state with a current can be generated in the one-dimensional model of interacting spinless fermions with a flux quench. Moreover, an extended GGE involving the quasilocal conserved quantities can be formulated for this case. © 2014 American Physical Society.

Znidaric M.,University of Ljubljana
Physical Review Letters | Year: 2014

We consider a one-dimensional XX spin chain in a nonequilibrium setting with a Lindblad-type boundary driving. By calculating large-deviation rate function in the thermodynamic limit, a generalization of free energy to a nonequilibrium setting, we obtain a complete distribution of current, including closed expressions for lower-order cumulants. We also identify two phase-transition-like behaviors in either the thermodynamic limit, at which the current probability distribution becomes discontinuous, or at maximal driving, when the range of possible current values changes discontinuously. In the thermodynamic limit the current has a finite upper and lower bound. We also explicitly confirm nonequilibrium fluctuation relation and show that the current distribution is the same under mapping of the coupling strength Γ→1/Γ. © 2014 American Physical Society.

Prosen T.,University of Ljubljana
Physical Review Letters | Year: 2014

We discuss the current carrying nonequilibrium steady state of an open fermionic Hubbard chain that is strongly driven by Markovian incoherent processes localized at the chain ends. An explicit form of an exact many-body density operator for any value of the coupling parameter is presented. The structure of a matrix product form of the solution is encoded in terms of a novel diagrammatic technique that should allow for generalization to other integrable nonequilibrium models. © 2014 American Physical Society.

Znidaric M.,University of Ljubljana
Physical Review Letters | Year: 2013

We show that in a nonintegrable spin ladder system with the XX type of coupling along the legs and the XXZ type along the rungs there are invariant subspaces that support ballistic magnetization transport. In the complementary subspace the transport is found to be diffusive. This shows that (i) quantum chaotic systems can possess ballistic subspaces, and (ii) diffusive and ballistic transport modes can coexist in a rather simple nonintegrable model. In the limit of an infinite anisotropy in rungs the system studied is equivalent to the one-dimensional Hubbard model. © 2013 American Physical Society.

Buca B.,University of Ljubljana | Prosen T.,University of Ljubljana
Physical Review Letters | Year: 2014

We study the full counting statistics for interacting quantum many-body spin systems weakly coupled to the environment. In the leading order in the system-bath coupling, we derive exact spin current statistics for a large class of parity symmetric spin-1/2 systems driven by a pair of Markovian baths with local coupling operators. Interestingly, in this class of systems the leading-order current statistics are universal and do not depend on details of the Hamiltonian. Furthermore, in the specific case of a symmetrically boundary driven anisotropic Heisenberg (XXZ) spin-1/2 chain, we explicitly derive the third-order nonlinear corrections to the current statistics. © 2014 American Physical Society.

Kotnik P.,University of Ulm | Kotnik P.,University of Ljubljana | Fischer-Posovszky P.,University of Ulm | Wabitsch M.,University of Ulm
European Journal of Endocrinology | Year: 2011

Adipose tissue is an endocrine organ secreting biologically active factors called adipokines that act on both local and distant tissues. Adipokines have an important role in the development of obesity-related comorbidities not only in adults but also in children and adolescents. Retinol binding protein 4 (RBP4) is a recently identified adipokine suggested to link obesity with its comorbidities, especially insulin resistance, type 2 diabetes (T2D), and certain components of the metabolic syndrome. However, data, especially resulting from the clinical studies, are conflicting. In this review, we summarize up-to-date knowledge on RBP4's role in obesity, development of insulin resistance, and T2D. Special attention is given to studies on children and adolescents. We also discuss the role of possible confounding factors that should be taken into account when critically evaluating published studies or planning new studies on this exciting adipokine. © 2011 European Society of Endocrinology.

Prelovsek S.,University of Ljubljana | Prelovsek S.,Jozef Stefan Institute | Leskovec L.,Jozef Stefan Institute
Physical Review Letters | Year: 2013

A candidate for the charmonium(like) state X(3872) is found 11±7 MeV below the DD̄* threshold using dynamical Nf=2 lattice simulation with JPC=1++ and I=0. This is the first lattice simulation that establishes a candidate for X(3872) in addition to the nearby scattering states DD̄* and J/ψω, which inevitably have to be present in dynamical QCD. We extract large and negative DD̄* scattering length a0DD*=-1.7±0.4 fm and the effective range r0DD *=0.5±0.1 fm, but their reliable determination will have to wait for a simulation on a larger volume. In I=1 channel, only the DD ̄* and J/ψρ scattering states are found and no candidate for X(3872). This is in agreement with the interpretation that X(3872) is dominantly I=0, while its small I=1 component arises solely from the isospin breaking and is therefore absent in our simulation with m u=md. © 2013 American Physical Society.

Klen J.,General Hospital Trbovlje | Dolzan V.,University of Ljubljana | Janez A.,University of Ljubljana
European Journal of Clinical Pharmacology | Year: 2014

Purpose: Sulphonylureas (SU) are widely used in the management of type 2 diabetes. We investigated the influence of CYP2C9, KCNJ11 and ABCC8 polymorphisms on the response to SU currently used in everyday clinical practice. Methods: Patients treated for type 2 diabetes with sulphonylurea in monotherapy (n=21) or in combination with metformin (n=135) were provided with glucose-monitoring devices and instructed to measure fasting blood glucose levels once per week and additionally at any signs and symptoms suggesting low blood glucose for a period of three months. All patients were genotyped for CYP2C9 rs1799853 and rs1057910 (*2 and *3 allele, respectively), KCNJ11 rs5219 and rs5215, and ABCC8 rs757110. Results: The average duration of diabetes in the study group was 10.6±7.1 years. Most of the patients achieved relatively good blood glucose control (HbA1c 7.0±0.9). In total, 76 hypoglycemia events were observed (mean 0.48±1.3). No severe hypoglycemia was reported; the lowest blood glucose was 2.1 mmol/l. Although 124 (79.5 %) patients never experienced hypoglycemia, 32 (20.5 %) patients experienced from one to eight events. None of the investigated polymorphisms influenced HbA1c levels or risk for hypoglycemia episodes in the whole group of patients. CYP2C9 genotype significantly influenced the occurrence of hypoglycemia events among the elderly patients (aged 60 years and over; n=103). Among them, carriers of two wild-type alleles suffered 0.36±0.98 events, while patients with one or two polymorphic alleles had 0.79±1.7 or 2.67±4.6 events, respectively (p=0.014). Conclusions: Our results indicate that the CYP2C9 genotype may influence the risk for hypoglycemia events in elderly patients, but not in the overall population of type 2 diabetes patients. © 2014 Springer-Verlag.

Prosen T.,University of Ljubljana | Zunkovic B.,University of Chile
Physical Review Letters | Year: 2013

We demonstrate that a completely integrable classical mechanical model, namely the lattice Landau-Lifshitz classical spin chain, supports diffusive spin transport with a finite diffusion constant in the easy-axis regime, while in the easy-plane regime, it displays ballistic transport in the absence of any known relevant local or quasilocal constant of motion in the symmetry sector of the spin current. This surprising finding should open the way towards analytical computation of diffusion constants for integrable interacting systems and hints on the existence of new quasilocal classical conservation laws beyond the standard soliton theory. © 2013 American Physical Society.

Ahlin Grabnar P.,University of Ljubljana | Kristl J.,University of Ljubljana
Journal of Microencapsulation | Year: 2011

Over the past few decades, nanoparticle (NP) formulation has been the subject of extensive research. The choice of a suitable NP formulation technique is dependent on the physicochemical properties of the drug, such as solubility and chemical stability. Different NP manufacturing methods enable modification of the physicochemical characteristics such as size, structure, morphology and surface texture, but also affect the drug loading, drug entrapment efficiency and release kinetics. This review covers an update on the state of art of the manufacturing of polymeric NPs from preformed polymers. Both, conventional methods for NP preparation, such as spontaneous formulation and emulsification-based methods, and new approaches in NP technology are presented. A comparative analysis is given for polymer, drug and solvent nature, toxicity, purification, drug stability and scalability of the method. The information obtained allows establishing criteria for selecting a method for preparation of NPs according to its advantages and limitations. © 2011 Informa UK Ltd All rights reserved: reproduction in whole or part not permitted.

Lenarcic Z.,Jozef Stefan Institute | Prelovsek P.,Jozef Stefan Institute | Prelovsek P.,University of Ljubljana
Physical Review Letters | Year: 2013

We present a calculation of the recombination rate of the excited holon-doublon pairs based on the two-dimensional model relevant for undoped cuprates, which shows that fast processes, observed in pump-probe experiments on Mott-Hubbard insulators in the picosecond range, can be explained even quantitatively with the multimagnon emission. The precondition is the existence of the Mott-Hubbard bound exciton of the s-type. We find that its decay is exponentially dependent on the Mott-Hubbard gap and on the magnon energy, with a small prefactor, which can be traced back to strong correlations and consequently large exciton-magnon coupling. © 2013 American Physical Society.

Ozbolt M.,University of Ljubljana | Kitanovski A.,University of Ljubljana | Tusek J.,University of Ljubljana | Poredos A.,University of Ljubljana
International Journal of Refrigeration | Year: 2014

Electrocaloric refrigeration represents a new, alternative technology for refrigeration, cooling, heating or even power generation. As a technology it can be characterized as being analogous to magnetocaloric energy conversion. Therefore, any knowledge acquired from magnetocaloric energy conversion can be usefully applied to future electrocaloric applications. This article presents a review of electrocaloric refrigeration and heat pumping, supported by a basic description of the thermodynamics of the different processes. There are also a few examples provided to demonstrate the operation of the electrocaloric refrigeration cycle. A comprehensive review of existing electrocaloric materials and their properties is given. Since it is one of the most important issues with regard to electrocaloric regenerators, different heat-transfer mechanisms and solutions are presented and discussed. These are required to obtain both the high energy efficiency as well as the large power density in a device, i.e.; to be able to produce a compact device. This article also presents some guidelines for the future research and development of electrocaloric refrigeration and heat pumping. © 2013 Elsevier Ltd and IIR. All rights reserved.

Zupanc T.,University of Ljubljana
European Addiction Research | Year: 2012

Background: Addiction is a major social and health problem. Studies on suicide and alcohol at the individual and aggregated level have confirmed a link between alcohol and suicide. Aim: To assess the impact of the new national alcohol policy in Slovenia on the blood alcohol concentration (BAC) in BAC-positive suicide victims before, during and after the implementation of the new national alcohol policy in 2003. Method: Blood samples were collected by forensic pathologists during medicolegal autopsies of suicide victims in order to establish their BAC levels at the time of death. BAC was measured using two routine independent headspace gas chromatography methods (HSS-GC-FID) and expressed in grams per kilogram. Results: During the period before the implementation of the act which limited the availability of alcohol in Slovenia, the BACs of BAC-positive suicide victims were higher than those tested in the period after the implementation of the act. Conclusion: Despite certain limitations, this study demonstrates that legislation measures restricting alcohol availability may be an effective measure of BAC reduction in BAC-positive suicide victims. Copyright © 2012 S. Karger AG, Basel.

Pozar T.,University of Ljubljana | Mozina J.,University of Ljubljana
Physical Review Letters | Year: 2013

The reflection of light from the surface of an elastic solid gives rise to various types of elastic waves that propagate inside the solid. The weakest waves are generally those that are generated by the radiation pressure acting during the reflection of the light. Here, we present the first quantitative measurement of such light-pressure-induced elastic waves inside an ultrahigh-reflectivity mirror. Amplitudes of a few picometers were observed at the rear side of the mirror with a displacement-measuring conical piezoelectric sensor when laser pulses with a fluence of 1 J/cm2 were reflected from the front side of the mirror. © 2013 American Physical Society.

Prosen T.,University of Ljubljana | Znidaric M.,University of Ljubljana
Physical Review Letters | Year: 2013

We propose to quantify the complexity of nonequilibrium steady state density operators, as well as of long-lived Liouvillian decay modes, in terms of the level spacing distribution of their spectra. Based on extensive numerical studies in a variety of models, some solvable and some unsolved, we conjecture that the integrability of density operators (e.g., the existence of an algebraic procedure for their construction in finitely many steps) is signaled by a Poissonian level statistics, whereas in the generic nonintegrable cases one finds level statistics of a Gaussian unitary ensemble of random matrices. Eigenvalue statistics can therefore be used as an efficient tool to identify integrable quantum nonequilibrium systems. © 2013 American Physical Society.

Mohler D.,Fermi National Accelerator Laboratory | Lang C.B.,University of Graz | Leskovec L.,Jozef Stefan Institute | Prelovsek S.,Jozef Stefan Institute | And 2 more authors.
Physical Review Letters | Year: 2013

The scalar meson Ds0*(2317) is found 37(17) MeV below the DK threshold in a lattice simulation of the JP=0+ channel using, for the first time, both DK as well as s̄c interpolating fields. The simulation is done on Nf=2+1 gauge configurations with mπ 156 MeV, and the resulting MDs0*-14(MDs+3M Ds*)=266(16) MeV is close to the experimental value 241.5(0.8) MeV. The energy level related to the scalar meson is accompanied by additional discrete levels due to DK scattering states. The levels near threshold lead to the negative DK scattering length a0=-1.33(20) fm that indicates the presence of a state below threshold. © 2013 American Physical Society.

Prosen T.,University of Ljubljana | Ilievski E.,University of Ljubljana
Physical Review Letters | Year: 2013

For fundamental integrable quantum chains with deformed symmetries we outline a general procedure for defining a continuous family of quasilocal operators whose time derivative is supported near the two boundary sites only. The program is implemented for a spin 1/2 XXZ chain, resulting in improved rigorous estimates for the high temperature spin Drude weight. © 2013 American Physical Society.

Babic J.,University of Ljubljana | Pavko A.,University of Ljubljana
Journal of Industrial Microbiology and Biotechnology | Year: 2012

White-rot fungi are extensively used in various submerged biotechnology processes to produce ligninolytic enzymes. Transfer of the process from the laboratory to the industrial level requires optimization of the cultivation conditions on the laboratory scale. An interesting area of optimization is pellet growth since this morphological form solves problems such as the decreased oxygen concentration, limited heat, and nutrient transport, which usually occur in dispersed mycelium cultures. Many submerged fermentations with basidiomycetes in pellet form were done with Phanerochaete, Trametes, and Bjerkandera species, among others. In our study, another promising basidiomycete, D. squalens, was used for ligninolytic enzyme production. With the addition of wood particles (sawdust) as a natural inducer and optimization of mixing and aeration conditions in laboratory stirred tank (STR) and bubble column (BCR) reactors on pellet growth and morphology, the secretion of laccase and the manganese-dependent peroxidase into the medium was substantially enhanced. The maximum mean pellet radius was achieved after 10 days in the BCR (5.1 mm) where pellets were fluffy and 5 days in the STR (3.5 mm) where they were round and smooth. The maximum Lac activity (1,882 U l -1 ) was obtained after 12 days in the STR, while maximum MnP activity (449.8 U l -1 ) occurred after 18 days in the BCR. The pellet size and morphology depended on the agitation and aeration conditions and consequently influenced a particular enzyme synthesis. The enzyme activities were high and comparable with the activities found for other investigations in reactors with basidiomycetes in the form of pellets. © 2011 Society for Industrial Microbiology and Biotechnology.

Prosen T.,University of Ljubljana
Nuclear Physics B | Year: 2014

A continuous family of quasilocal exact conservation laws is constructed in the anisotropic Heisenberg (XXZ) spin-1/2 chain for periodic (or twisted) boundary conditions and for a set of commensurate anisotropies densely covering the entire easy plane interaction regime. All local conserved operators follow from the standard (Hermitian) transfer operator in fundamental representation (with auxiliary spin s = 1/2), and are all even with respect to a spin flip operation. However, the quasilocal family is generated by differentiation of a non-Hermitian highest weight transfer operator with respect to a complex auxiliary spin representation parameter s and includes also operators of odd parity. For a finite chain with open boundaries the time derivatives of quasilocal operators are not strictly vanishing but result in operators localized near the boundaries of the chain. We show that a simple modification of the non-Hermitian transfer operator results in exactly conserved, but still quasilocal operators for periodic or generally twisted boundary conditions. As an application, we demonstrate that implementing the new exactly conserved operator family for estimating the high-temperature spin Drude weight results, in the thermodynamic limit, in exactly the same lower bound as for almost conserved family and open boundaries. Under the assumption that the bound is saturating (suggested by agreement with previous thermodynamic Bethe ansatz calculations) we propose a simple explicit construction of infinite time averages of local operators such as the spin current. © 2014 The Author.

The PhysioNet Challenge 2013 focused to develop accurate algorithms for locating QRS complexes and estimating the QT interval in noninvasive fetal ECG (FECG) signals obtained from noninvasive abdominal recordings in pregnant women. © 2013 CCAL.

Alibegovic A.,University of Ljubljana
Journal of Forensic and Legal Medicine | Year: 2014

The determination of the time of death or the postmortem interval (PMI) is one of the most important and frequently asked questions in forensic medicine. The methods used for PMI determination are based largely on early and late postmortem changes. The determination of the PMI during the late postmortem changes is based primarily on a subjective assessment and is less precise due to the lack of objective methods. Different studies have presented a gradual decrease in chondrocytes' viability but these researches did not answer the question whether we can use the decrease of chondrocytes' viability for an objective PMI determination. The structure and anatomical location of the cartilage together with its mechanical, physical and chemical properties enable chondrocytes to survive for several weeks after the individual's death, and give cartilage the attributes of a compartment. Therefore, cartilage could be a new parameter for PMI determination. This idea had been partially confirmed by a few in vitro studies. The next step in testing this idea should be an extensive in corpore study. © 2014 Elsevier Ltd and Faculty of Forensic and Legal Medicine. All rights reserved.

Sustar V.,University of Ljubljana
International journal of nanomedicine | Year: 2011

Shedding of nanoparticles from the cell membrane is a common process in all cells. These nanoparticles are present in body fluids and can be harvested by isolation. To collect circulating nanoparticles from blood, a standard procedure consisting of repeated centrifugation and washing is applied to the blood samples. Nanoparticles can also be shed from blood cells during the isolation process, so it is unclear whether nanoparticles found in the isolated material are present in blood at sampling or if are they created from the blood cells during the isolation process. We addressed this question by determination of the morphology and identity of nanoparticles harvested from blood. The isolates were visualized by scanning electron microscopy, analyzed by flow cytometry, and nanoparticle shapes were determined theoretically. The average size of nanoparticles was about 300 nm, and numerous residual blood cells were found in the isolates. The shapes of nanoparticles corresponded to the theoretical shapes obtained by minimization of the membrane free energy, indicating that these nanoparticles can be identified as vesicles. The concentration and size of nanoparticles in blood isolates was sensitive to the temperature during isolation. We demonstrated that at lower temperatures, the nanoparticle concentration was higher, while the nanoparticles were on average smaller. These results indicate that a large pool of nanoparticles is produced after blood sampling. The shapes of deformed blood cells found in the isolates indicate how fragmentation of blood cells may take place. The results show that the contents of isolates reflect the properties of blood cells and their interaction with the surrounding solution (rather than representing only nanoparticles present in blood at sampling) which differ in different diseases and may therefore present a relevant clinical parameter.

Brecelj J.,University of Ljubljana
Documenta ophthalmologica. Advances in ophthalmology | Year: 2014

In routine clinical evaluation of optic neuritis and chiasmal tumours, pattern electroretinography and visual evoked potentials (VEPs) to pattern-reversal stimulation are useful examinations. Similarly, in achiasmia and ocular albinism, VEPs to flash and pattern-onset stimulation provide relevant information. The role of visual electrophysiology in these diseases is to assess potential dysfunction of the visual pathway: (a) at the acute stage of optic neuritis, to determine the magnitude of conduction block of the optic nerve fibres; (b) at the clinical recovery stage of optic neuritis, to determine optic nerve conduction delay due to demyelination, and to follow possible remyelination; (c) at the recovery of optic neuritis when visual acuity does not normalise, to define loss of optic nerve fibres and retrograde degeneration of retinal ganglion cells; (d) in tumours at the chiasm, to detect abnormal conduction along the crossed and/or uncrossed fibres; and (e) in achiasmia or albinism, which are both congenital disorders associated with nystagmus, to detect achiasmia and absence of or reduced optic nerve fibre decussation at the chiasm, or to detect ocular albinism and excess of optic nerve fibre decussation at the chiasm. In optic neuritis, two recent examinations have been used to detect retrograde axonal degeneration: photopic negative response of the electroretinogram, to assess dysfunction of ganglion cell axons; and optic coherence tomography, to measure thinning of the retinal nerve fibre layer. In optic neuritis, multifocal VEPs provide a promising clinical examination, because this can show areas that are associated with normal or abnormal optic nerve fibre function. Visual electrophysiology defines function of the visual pathway and is relevant: (1) in optic neuritis, when visual acuity does not recover well; (2) in tumours of the chiasm with normal visual fields, as in paediatric patients who cannot adequately perform perimetry; and (3) in children with congenital nystagmus and suspected achiasmia or ocular albinism.

The growth of membrane nanotubes is crucial for intercellular communication in both normal development and pathological conditions. Therefore, identifying factors that influence their stability and formation are important for both basic research and in development of potential treatments of pathological states. Here we investigate the effect of cholera toxin B (CTB) and temperature on two pathological model systems: urothelial cell line RT4, as a model system of a benign tumor, and urothelial cell line T24, as a model system of a metastatic tumor. In particular, the number of intercellular membrane nanotubes (ICNs; ie, membrane nanotubes that bridge neighboring cells) was counted. In comparison with RT4 cells, we reveal a significantly higher number in the density of ICNs in T24 cells not derived from RT4 without treatments (P = 0.005), after 20 minutes at room temperature (P = 0.0007), and following CTB treatment (P = 0.000025). The binding of CTB to GM1-lipid complexes in membrane exvaginations or tips of membrane nanotubes may reduce the positive spontaneous (intrinsic) curvature of GM1-lipid complexes, which may lead to lipid mediated attractive interactions between CTB-GM1-lipid complexes, their aggregation and consequent formation of enlarged spherical tips of nanotubes. The binding of CTB to GM1 molecules in the outer membrane leaflet of membrane exvaginations and tips of membrane nanotubes may also increase the area difference between the two leaflets and in this way facilitate the growth of membrane nanotubes.

Trcek D.,University of Ljubljana
Ad Hoc Networks | Year: 2013

Pervasive computing is already becoming a reality and one crucial consequence of this fact is endangered privacy. Now taking into account typical properties of pervasive computing devices, which are weak computing power and stringent energy or power consumption limitations, lightweight solutions are a must. This especially holds true for all-in-silicon objects like radio frequency identification tags, or RFIDs. Many solutions in this area are called lightweight, but being lightweight requires conformance to quantitative requirements using certain metrics. A solution that adheres to such requirements is a new privacy enabling protocol for RFIDs that outperforms other architecturally similar protocols, and this presents the first contribution of this paper. Further, privacy is not only a matter of technical solutions, but increasingly so a matter of organizational processes. This fact calls for further addressing of supporting its formal treatment in business contexts. This paper provides a basis for formal addressing of privacy from business processes perspective, and this is its second main contribution. © 2013 Elsevier B.V.

Ravnik R.,University of Ljubljana | Solina F.,University of Ljubljana
Interacting with Computers | Year: 2013

We present a quantitative study of digital signage audience measurement using computer vision. We developed a camera-enhanced digital signage display that acquires audience measurement metrics with computer vision algorithms. Temporal metrics of a person's dwell time, display in-view time and attention time are extracted. The system also determines demographic metrics of the gender and age group. The digital signage display was deployed in a real-world environment of a clothing boutique, where demographic and viewership data of 1294 store customers were recorded, manually verified and analysed. The analysis shows that 35% of customers specifically looked-at the display, having the average attention time of 0.7 s. Interestingly, the attention time was substantially higher for men (1.2 s) than for women (0.4 s). Age group comparison reveals that children (1-14 years) are the most responsive to the digital signage. Finally, the analysis shows that the average attention time is significantly higher when displaying the dynamic content (0.9 s) when compared with the static content (0.6 s). © 2013 The Author.

Batista M.,University of Ljubljana
International Journal of Solids and Structures | Year: 2015

The Jacobi test is used to analyze the stability of planar equilibrium configurations for clamped-clamped and clamped-hinged elastic rods. The governing equilibrium equation and Jacobi equation are derived from variational principles, and their solution is presented in terms of the Jacobi elliptical functions. The critical equation, which determines the stability properties of rod equilibrium, is solved numerically. The results of the analysis are presented in graphical form as instability regions on bifurcation diagrams. © 2015 Elsevier Ltd. All rights reserved.

Zbontar J.,University of Ljubljana | Le Cun Y.,New York University
Proceedings of the IEEE Computer Society Conference on Computer Vision and Pattern Recognition | Year: 2015

We present a method for extracting depth information from a rectified image pair. We train a convolutional neural network to predict how well two image patches match and use it to compute the stereo matching cost. The cost is refined by cross-based cost aggregation and semiglobal matching, followed by a left-right consistency check to eliminate errors in the occluded regions. Our stereo method achieves an error rate of 2.61% on the KITTI stereo dataset and is currently (August 2014) the top performing method on this dataset. © 2015 IEEE.

Berginc M.,University of Ljubljana | Krasovec U.O.,University of Ljubljana | Topic M.,University of Ljubljana
Solar Energy Materials and Solar Cells | Year: 2014

Ionic liquid based dye-sensitized solar cells (DSSCs) were exposed to outdoor irradiation for seven months (April-October, 906 kWh/m2, latitude 46 2'39.39«N, longitude 14 29'18.28»E) under short-circuit, open-circuit, and quasi maximum-power-point regime. As a reference we kept a series of DSSCs in the dark at room temperature under open-circuit regime. The performance of the DSSCs was evaluated indoor under standard test conditions prior to ageing, twice during ageing and after ageing. Additionally, the electroluminescence and transmittance imaging were used to follow the evolution of local defects with ageing. Operating regime has a strong influence on the ageing of DSSCs but despite this the performance of DSSCs remained remarkably stable. The exceptions were cells aged under short-circuit regime, which led to a significant decrease in JSC. This resulted from the degradation of the dye molecules and a decrease in the tri-iodide concentration in the electrolyte. © 2013 Elsevier B.V.

Humar M.,Jozef Stefan Institute | Musevic I.,Jozef Stefan Institute | Musevic I.,University of Ljubljana
Optics Express | Year: 2010

We demonstrate a tunable and omnidirectional microlaser in the form of a microdroplet of a dye-doped, cholesteric liquid crystal in a carrier fluid. The cholesteric forms a Bragg-onion optical microcavity and the omnidirectional 3D lasing is due to the stimulated emission of light from the dye molecules in the liquid crystal. The lasing wavelength depends solely on the natural helical period of the cholesteric and can be tuned by varying the temperature. Millions of microlasers can be formed simply by mixing a liquid crystal, a laser dye and a carrier fluid, thus providing microlasers for soft-matter photonic devices. © 2010 Optical Society of America.

Andersen P.K.,Copenhagen University | Pohar Perme M.,University of Ljubljana
Statistical Methods in Medical Research | Year: 2010

We review recent work on the application of pseudo-observations in survival and event history analysis. This includes regression models for parameters like the survival function in a single point, the restricted mean survival time and transition or state occupation probabilities in multi-state models, e.g. the competing risks cumulative incidence function. Graphical and numerical methods for assessing goodness-of-fit for hazard regression models and for the Fineĝ€"Gray model in competing risks studies based on pseudo-observations are also reviewed. Sensitivity to covariate-dependent censoring is studied. The methods are illustrated using a data set from bone marrow transplantation.

Various explicit reformulations of time-dependent solutions for the classical two-step irreversible Michaelis-Menten enzyme reaction model have been described recently. In the current study, I present further improvements in terms of a generalized integrated form of the Michaelis-Menten equation for computation of substrate or product concentrations as functions of time for more real-world, enzyme-catalyzed reactions affected by the product. The explicit equations presented here can be considered as a simpler and useful alternative to the exact solution for the generalized integrated Michaelis-Menten equation when fitted to time course data using standard curve-fitting software. © 2011 Elsevier Inc. All rights reserved.

Silva C.A.,University of Sao Paulo | Avcin T.,University of Ljubljana | Br