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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.

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.

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.

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.

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.

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.

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.

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.

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.

The application of wood in seawater is one of the most challenging. Impregnated wood is exposed to leaching and to various marine borers, Limnoria sp. and Teredo sp. being the most important ones. The present research investigated the durability of pine wood impregnated with copper-amine based preservative solution (Silvanolin) of different concentrations exposed to the seawater according to EN 275 standard. Performance of Silvanolin treated wood was compared to the performance of reference wood (Quercus sp., Castanea sativa, Larix decidua). After 10, 18 and 32 months of exposure, specimens were removed and assessed. The results show clearly that the reference wood species were completely degraded after 10 months of exposure. On the other hand, it became evident that Silvanolin prolonged the service life of wood exposed to the sea. The specimens impregnated with the lowest concentration of preservative solution (CCu = 0.31 %) were slightly decayed. The specimens, impregnated with higher concentrations of copper (CCu > 0.31 %), showed almost no defects after expsore to marine borers.

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.

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.

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.

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.

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.

Mervic L.,University of Tubingen | 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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

Rizner T.L.,University of Ljubljana
Expert Review of Molecular Diagnostics | Year: 2015

Endometriosis is defined as the presence of endometrial glands and stroma outside the uterus, in different parts of the peritoneal cavity. It affects up to 10% of reproductive-age women and up to 50% of women with infertility. Surgical diagnosis of endometriosis is still the gold standard, with no diagnostic biomarkers available. Medical therapies target the symptoms and not the disease itself, and surgical treatment cannot prevent recurrence. As peritoneal fluid reflects the altered peritoneal microenvironment of endometriosis patients, it can provide a wealth of information on pathophysiological processes and potential biomarkers. This report reviews the molecular biomarkers identified in peritoneal fluid over the last 5 years and discusses their potential applications for diagnosis, prognosis and drug therapy. © 2015 Informa UK, Ltd.

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.

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.

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.

Golicnik M.,University of Ljubljana
Biochemical Engineering Journal | Year: 2012

This article presents closed-form analytic solutions to three illustrative problems in biochemical kinetics that have usually been considered solvable only by various numerical methods. The problems solved concern two enzyme-catalyzed reaction systems that obey diversely modified Michaelis-Menten rate equations, and biomolecule surface binding that is limited by mass transport. These problems involve the solutions of transcendental equations that include products of variables and their logarithms. Such equations are solvable by the use of the Lambert W(x) function. Thus, these standard kinetics examples are solved in terms of W(x) to show the applicability of this commonly unknown function to the biochemical community. Hence, this review first of all describes the mathematical definition and properties of the W(x) function and its numerical evaluations, together with analytical approximations, and then it describes the use of the W(x) function in biochemical kinetics. Other applications of the function in various engineering sciences are also cited, although not described. © 2012 Elsevier B.V.

Kralj-Iglic V.,University of Ljubljana
International Journal of Nanomedicine | Year: 2012

Membranous nanostructures, such as nanovesicles and nanotubules, are an important pool of biological membranes. Recent results indicate that they constitute cell-cell communication systems and that cancer development is influenced by these systems. Nanovesicles that are pinched off from cancer cells can move within the circulation and interact with distant cells. It has been suggested and indicated by experimental evidence that nanovesicles can induce metastases from the primary tumor in this way. Therefore, it is of importance to understand better the mechanisms of membrane budding and vesiculation. Here, a theoretical description is presented concerning consistently related lateral membrane composition, orientational ordering of membrane constituents, and a stable shape of nanovesicles and nanotubules. It is shown that the character of stable nanostructures reflects the composition of the membrane and the intrinsic shape of its constituents. An extension of the fluid mosaic model of biological membranes is suggested by taking into account curvature-mediated orientational ordering of the membrane constituents on strongly anisotropically curved regions. Based on experimental data for artificial membranes, a possible antimetastatic effect of plasma constituents via mediation of attractive interaction between membranous structures is suggested. This mediated attractive interaction hypothetically suppresses nanovesiculation by causing adhesion of buds to the mother membrane and preventing them from being pinched off from the membrane. © 2012 Kralj-Iglic, publisher and licensee Dove Medical Press Ltd.

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.

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.

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.

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.

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.

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.

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.

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.

Nagode M.,University of Ljubljana | Langler F.,BorgWarner Turbo Systems Engineering GmbH | Hack M.,LMS Deutschland
International Journal of Fatigue | Year: 2011

The damage operator approach is extended to time dependent viscoplasticity and creep. The oxidation is taken into account indirectly. Time efficient viscoplastic approximation based on the nonlinear Maxwell model and the corresponding lifetime prediction is presented. Both thermo-mechanical fatigue tests on the specimens and the thermal shock tests on turbine housings of a turbocharger subject to a complex change of temperature and strain are conducted for identification and verification purposes. The material is casting material Ni-resist D-5S. The research points out that the mean stress correction and the multiaxial criterion affect the predictive lifetimes significantly. For the turbine housing of a turbocharger the Smith-Watson-Topper mean stress correction, tensile-compressive creep and the critical plane mode I approach is the most suitable parameter combination. The lifetime predictions are convenient. The time consuming elastoviscoplastic finite element analyses can thus often be replaced by the elastoplastic FEA with kinematic hardening even at extreme conditions. © 2010 Elsevier Ltd. All rights reserved.

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..

Van Hoof J.,HU University of Applied Sciences Utrecht | Mazej M.,University of Ljubljana | Hensen J.L.M.,TU Eindhoven
Frontiers in Bioscience | Year: 2010

Thermal comfort -the state of mind, which expresses satisfaction with the thermal environment- is an important aspect of the building design process as modern man spends most of the day indoors. This paper reviews the developments in indoor thermal comfort research and practice since the second half of the 1990s, and groups these developments around two main themes; (i) thermal comfort models and standards, and (ii) advances in computerization. Within the first theme, the PMV-model (Predicted Mean Vote), created by Fanger in the late 1960s is discussed in the light of the emergence of models of adaptive thermal comfort. The adaptive models are based on adaptive opportunities of occupants and are related to options of personal control of the indoor climate and psychology and performance. Both models have been considered in the latest round of thermal comfort standard revisions. The second theme focuses on the ever increasing role played by computerization in thermal comfort research and practice, including sophisticated multi-segmental modeling and building performance simulation, transient thermal conditions and interactions, thermal manikins.

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.

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.

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.

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.

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.

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.

Shrestha A.,North Dakota State University | Bohinc K.,University of Ljubljana | May S.,North Dakota State University
Langmuir | Year: 2012

Electrostatic interactions affect the immersion depth of charged nanoparticles that are trapped at an air-water interface. Recent experiments indicate that upon adding salt negatively charged nanoparticles penetrate deeper into the aqueous phase, whereas positively charged nanoparticles exhibit opposite behavior. It has been proposed that this unexpected lack of invariance with respect to the nanoparticle's charge reversal is caused by a negative surface potential of the air-water interface. To support this hypothesis, we have performed detailed calculations based on nonlinear Poisson-Boltzmann theory of individual spherical particles that are either negatively or positively charged and reside at the interface between air and water. The nanoparticles possess dissociable surface groups that become charged when exposed to the aqueous environment. We calculate the optimal immersion depth from a numerical minimization of the total free energy, which we express as the sum of a surface tension term and an electrostatic contribution. In all calculations we fix the surface potential at the air-water surface at -50 mV. In qualitative agreement with recent experiments, our model predicts opposite behaviors of negatively versus positively charged nanoparticles: adding salt increases/decreases the water immersion depth of negatively/positively charged nanoparticles. © 2012 American Chemical Society.

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.

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.

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.

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).

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.

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.

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.

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.

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.

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

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.

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.

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.

Boh B.,University of Ljubljana
Recent Patents on Anti-Cancer Drug Discovery | Year: 2013

Based on the analysis of more than 270 patents and scientific articles, this state-of-the-art review presents Ganoderma lucidum, a medicinal basidiomycete mushroom with immunomodulatory and anti-cancer effects. Cultivation methods for the commercial production of G. lucidum fruit bodies and mycelia are summarized, with main active compounds of triterpenoids, polysaccharides, and proteins, often found in forms of proteoglycans or glycopeptides. Pharmacological effects with emphasis on anti-cancer and immunomodulatory functions are presented, separately for spores and dry mycelia, and for the groups of triterpenoids, polysaccharides, proteins and glycoproteins. Patents disclosing preparation methods of extracts and purified pharmaceutical isolates are reviewed, and examples of anti-cancer formulations, used as pharmaceuticals or nutraceuticals, are given. The review suggests that according to the present understanding, the anti-cancer activity of G. lucidum may be attributed to at least five groups of mechanisms: (1) activation/modulation of the immune response of the host, (2) direct cytotoxicity to cancer cells, (3) inhibition of tumor-induced angiogenesis, (4) inhibition of cancer cells proliferation and invasive metastasis behaviour, and (5) carcinogens deactivation with protection of cells. Although, the data from recent in vitro and in vivo studies demonstrate promising anti-cancer effects, a need is identified for further (1) isolation and purification of compounds, with deeper understanding of their individual and synergistic pharmacological effects, (2) molecular level studies of the antitumor and immuno-supportive mechanisms, (3) well designed in vivo tests and controlled clinical studies, and (4) standardisation and quality control for G. lucidum strains, cultivation processes, extracts and commercial formulations. © 2013 Bentham Science Publishers.

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.

Kusar S.,University of Ljubljana
Urbani Izziv | Year: 2012

In 2007, the United States witnessed a financial crisis that gradually developed into one of the most serious global financial and economic recessions in the history of (post)modern society. Its effects are numerous. This article studies one of its spatial effects; that is, newly built (after 2005) residential and office buildings that are either unfinished or already built but not fully occupied. In Ljubljana in November 2011, there were ninety-seven locations with unoccupied or partly occupied residential houses and office buildings or groups of houses and office buildings together with abandoned or active construction sites. The majority of the structures studied were predominately represented by several blocks of flats and groups of dwellings. The others are office buildings or buildings and complexes with distinctively mixed residential-business functions. There are more than 1,500 empty flats and almost 75,000 m2 of office area in the buildings surveyed. Spatial analysis showed that the structures surveyed are relatively scattered throughout Ljubljana. However, there were some clusters of buildings, especially in areas with the best accessibility. This article analyses the causes of this phenomenon, which is creating a new morphological element in Ljubljana. The article concludes by stating possible directions for future research.

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.

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.

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.

The paper addresses market-based congestion management (MBCM) in electric power systems taking into account the constraints of the electric power system (EPS) and the natural gas system (NGS). The proposed method is based on the countertrade methodology, where the system operator performs minimum-cost redispatching according to bids from generators and loads. The EPS is presented by the DC model for power flow calculation, which uses power transfer distribution factors (PTDFs) to describe the relation between generators/loads and line-power flows. The proposed solution applies the Benders decomposition method to decouple the problem into a master problem and subproblem. The master problem includes the bid-based redispatching for congestion relief and the EPS feasibility check. The subproblem checks the NGS operation feasibility when gas-fired generating units are redispatched in the master problem. Any NGS violations from the subproblem are incorporated into the master problem as power constraints for the next iteration of congestion management. The master problem is solved by linear programming. The NGS is presented in a nonlinear model and its feasibility check is performed using successive linear programming. Case studies illustrate the applicability of the proposed congestion management method on simple test models of the EPS and the NGS. © 2011 Elsevier Ltd.

David E.,National Research Institute Of Cryogenics And Isotope Technologies Cpraureni | Kopac J.,University of Ljubljana
International Journal of Hydrogen Energy | Year: 2011

This paper presents the major objectives involved in the development of a thin-layer palladium/ceramic composite membranes. These are (a) electroless plating of palladium on ceramic substrate, (b) characterization of palladium/ceramic composite formed, (c) evaluation of selectivity of the composite membranes for hydrogen separation. Commercially available ceramic was used as substrate for deposition of hydrogen selective layers. The substrate was coated with a thin palladium layer by electroless plating. The plating technique allowed to vary the thickness by depositing multiple metal layers. The details of the plating procedures and formulations of the plating solutions are presented. The palladium/ceramic composite membranes were studied by X-ray diffraction (XRD), scanning electron microscopy (SEM) and measuring the thickness of the coated film by a weight-gain method. The palladium film thicknesses were determined to be between 2 μm and 5 μm. Sorption performances of composite membranes were evaluated using temperature swing sorption process (TSSP). A gases mixture, provided from biomass gasification process, containing about 40-50% vol. H2 and numerous other gases such as CO, CO2, CH4, hydrocarbons C2-C 10, was used for the tests. In a first step, at first temperature (5-10 °C), the palladium/ceramic composites sorb only hydrogen from mixture and form hydride, all other components leave the sorbent. Then, subsequently, in a second step, energy is added to the sorbent, thus bringing it to a second temperature (105-120 °C) and hydrogen is desorbed while the pressure is reduced. The hydrogen obtained in desorption step is of a high purity (>99.5% vol). The results obtained show that this kind of composite membranes have certain separation selectivity for hydrogen and can have good industrial applications. © 2010, Hydrogen Energy Publications, LLC. Published by Elsevier Ltd. All rights reserved.

Ferbar Tratar L.,University of Ljubljana
International Journal of Production Economics | Year: 2015

Exponential smoothing methods are very commonly used for forecasting demand. Regarding the process of forecasting demand, the main approach towards the selection and optimisation of alternative methods relates to the minimisation of forecast error measures such as the mean square error (MSE). With regard to Pegels' classification of usage of proper forecasting methods, HW methods (additive and multiplicative) are appropriate for demand with trend and seasonality which corresponds to B-2 and B-3. But HW methods are not accurate enough for demand with large noise that is often a property of real data. In this paper we present improved an HW method for demand with noise and we demonstrate that a reduction in forecast error (MSE) can be reached. From the results, we prove that the proposed method is more accurate than the existing ones and that it is the proper choice for forecasting noisy demand. Furthermore, we show that essential reduction of supply chain costs can be achieved if we use improved the HW method for joined optimisation. © 2014 Elsevier B.V. All rights reserved.

The aim of our study was to assess the atherosclerotic burden in patients with the first symptoms of coronary artery disease (CAD). The study population consisted of 100 consecutive patients (new-onset severe angina or myocardial infarction) and 70 age and sex matched asymptomatic volunteers. Functional and morphologic atherosclerotic markers were sought in carotid, brachial and femoral arteries of all individuals by means of high-resolution ultrasonography, whereas coronary arteriography was performed in the CAD patients only. A total of 347 coronary lesions [230 (66%) obstructive] were discovered in the CAD patients as well as 105 peripheral plaques [26 (25%) obstructive]. The mean percentage diameter stenosis of the culprit coronary lesion was 83.8 ± 15.8%, the mean vessel score 1.7 (range 0-3), the mean stenosis score 19.8 (range 1.5-89.0), and the mean extent score 49.1% (range 10-65%). Endothelium-dependent vasodilation, as assessed by the brachial flow-mediated response (FMR), was reduced by 50% in the CAD patients (P < 0.001 vs. controls). Furthermore, endothelium-independent vasodilation was significantly impaired in all investigated peripheral arteries of the CAD patients (P < 0.05-0.001 vs. controls). Intima-media thickness (IMT) was increased in the carotid arteries of the CAD patients by 43%, in brachial arteries by 20% and in femoral arteries by 57% (P < 0.01-0.001 vs. controls). Decreased FMR or increased carotid IMT was found to be independent risk factors for the CAD, and they correlated with the coronary vessel and extent scores. In conclusion, the atherosclerotic process was quite advanced in coronary as well as peripheral arteries of our patients with the first clinical presentation of CAD. © 2011 Italian Federation of Cardiology.

Faletic S.,University of Ljubljana
European Journal of Physics | Year: 2015

Interviews with students suggest that even though they understand the formalism and the formal nature of quantum theory, they still often desire a mental picture of what the equations describe and some tangible experience with the wavefunctions. Here we discuss a mechanical wave system capable of reproducing correctly a mechanical equivalent of a quantum system in a potential, and the resulting waveforms in principle of any form. We have successfully reproduced the finite potential well, the potential barrier and the parabolic potential. We believe that these mechanical waveforms can provide a valuable experience base for introductory students to start from. We aim to show that mechanical systems that are described with the same mathematics as quantum mechanical, indeed behave in the same way. We believe that even if treated purely as a wave phenomenon, the system provides much insight into wave mechanics. This can be especially useful for physics teachers and others who often need to resort to concepts and experience rather than mathematics when explaining physical phenomena. © 2015 IOP Publishing Ltd.

Legan M.,University of Ljubljana
Bosnian Journal of Basic Medical Sciences | Year: 2010

Gallbladder carcinoma is the fifth most common malignancy of the gastrointestinal tract. The absolute characteristics of the disease are the high mortality rate due to the late discovery of a tumor and the low therapeutic possibilities except by surgical intervention. In oncology we can predict the outcome of the disease with a combination of classical standard clinico/pathological parameters (stage of the tumors, differentiation) and the intrinsic genetic and biochemical properties of the tumor. Such intrinzic properties of the tumors that are connected with the outcome of the disease are the denominators (markers). The author searched extensively for the expression and influence of 3 markers included in chronic inflammation and early carcinogenesis, cell cycle regulation and tissue hypoxia: cyclooxygenase-2 (COX-2), P53 gene and glucose transporter-i protein (GLUT-i). The author discusses their possible role in the development as well as fighting this disease, if specific medications targeting them were available.

Musevic I.,Jozef Stefan Institute | Musevic I.,University of Ljubljana
Liquid Crystals | Year: 2014

This contribution is a personal view of the rapidly developing subfield of nematic colloids, with an emphasis on possible applications of these materials in future photonic microdevices. A brief overview of the most important phenomena, observed in the past decade in nematic colloids is given. It is explained why integrated photonics based on microstructured liquid crystals is feasible and future challenges towards the realisation of integrated liquid crystal microphotonics are discussed. © 2013 © 2013 Taylor & Francis.

Kesic V.,University of Belgrade | Poljak M.,University of Ljubljana | Rogovskaya S.,Moscow Medical Academy
Cancer Epidemiology Biomarkers and Prevention | Year: 2012

Cervical cancer is an important public health care problem in Europe. The overall incidence rate of cervical cancer in Europe is 10.6 per 100,000. However, within Europe, the incidence rates significantly differ, being lower in Western Europe where prevention programs are better developed. Significantly higher are the incidence and mortality rates in Central and Eastern Europe, being in close correlation to the intensity of organized screening. Human papillomavirus (HPV) vaccines are being delivered to the low-incidence populations that already have extensive screening programs, whereas the high-incidence countries have not implemented the vaccination programs yet. The resolution of the problem of cervical cancer control in Europe will be a matter of the implementation of public health care programs across the whole continent. © 2012 AACR.

Prelovsek S.,University of Ljubljana | Prelovsek S.,Jozef Stefan Institute | Leskovec L.,Jozef Stefan Institute
Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics | Year: 2013

Recently three experiments reported a discovery of manifestly exotic Zc+(3900) in the decay to J/ψπ+, while J and P are experimentally unknown. We search for this state on the lattice by simulating the channel with JPC=1+- and I=1, and we do not find a candidate for Zc+(3900). Instead, we only find discrete scattering states DD-* and J/ψπ, which inevitably have to be present in a dynamical QCD. The possible reasons for not finding Zc+ may be that its quantum numbers are not 1+- or that the employed interpolating fields are not diverse enough. Simulations with additional types of interpolators will be needed to reach a more definite conclusion. © 2013 Elsevier B.V.

The standard Michaelis-Menten model equation must be extended to describe the kinetics of enzyme-catalyzed reactions that exhibit also spontaneous substrate depletion. Hence, its use is limited because the integrated form cannot be expressed in an explicit closed-form reformulation of the time-dependent solution. Thus, we construct explicit approximations to the solution of the extended Michaelis-Menten equation using the Adomian decomposition method, and this report presents its use to an illustrative problem that has been considered solvable only by numerical methods. We demonstrate here that the algebraic nature of these approximations to the solution of the extended Michaelis-Menten equation makes progress-curve analysis an attractive and useful alternative that can be simply performed using a standard nonlinear regression curve-fitting computer program.

Ribaric S.,University of Ljubljana
Oxidative Medicine and Cellular Longevity | Year: 2012

Nutrition has important long-term consequences for health that are not only limited to the individual but can be passed on to the next generation. It can contribute to the development and progression of chronic diseases thus effecting life span. Caloric restriction (CR) can extend the average and maximum life span and delay the onset of age-associated changes in many organisms. CR elicits coordinated and adaptive stress responses at the cellular and whole-organism level by modulating epigenetic mechanisms (e.g., DNA methylation, posttranslational histone modifications), signaling pathways that regulate cell growth and aging (e.g., TOR, AMPK, p53, and FOXO), and cell-to-cell signaling molecules (e.g., adiponectin). The overall effect of these adaptive stress responses is an increased resistance to subsequent stress, thus delaying age-related changes and promoting longevity. In human, CR could delay many diseases associated with aging including cancer, diabetes, atherosclerosis, cardiovascular disease, and neurodegenerative diseases. As an alternative to CR, several CR mimetics have been tested on animals and humans. At present, the most promising alternatives to the use of CR in humans seem to be exercise, alone or in combination with reduced calorie intake, and the use of plant-derived polyphenol resveratrol as a food supplement. © 2012 Samo Ribarič.

Znidaric M.,University of Ljubljana
Physical Review Letters | Year: 2016

Standard quantum state preparation methods work by preparing a required state locally and then distributing it to a distant location by a free-space propagation. We instead study procedures of preparing a target state at a remote location in the presence of an interacting background medium on which no control is required, manipulating only local dissipation. In mathematical terms, we characterize a set of reduced steady states stabilizable by local dissipation. An explicit local method is proposed by which one can construct a wanted one-site reduced steady state at an arbitrary remote site in a lattice of any size and geometry. In the chain geometry we also prove uniqueness of such a steady state. We demonstrate that the convergence time to fixed precision is smaller than the inverse gap, and we study robustness of the scheme in different medium interactions. © 2016 American Physical Society.

The probabilistic safety assessment is a standardized and widely accepted method for assessing and improving the reliability and safety of complex technologies, which is particularly true for the nuclear and the aerospace industry. The number of its applications to reliability of power systems is increasing. The objective of the paper is to collect and present the advantages and difficulties with the application of methods of probabilistic safety assessment to power systems reliability. The methods which apply the features of fault tree analysis to reliability analysis of power systems are presented and compared. The results are discussed and evaluated. The main advantages are connected with the facts that the methods are relative simple, the models are mostly available and that the data is intensively collected, evaluated and can serve as an excellent support for the quantitative part of the analyses. The difficulties are connected with different nature of components interaction within the power system compared to the safety systems in a nuclear power plant and with the large complexity of the power system, which distinguishes the term reliability into its static and dynamic parts known as adequacy and security. The results show large impact of common cause failures. The lack of data for the evaluations in the field of common cause failures of power systems increases significantly the uncertainty of the results. The uncertainty of the results may be reduced by improved data collection and analysis similarly as it is done in the nuclear safety. © 2011 Elsevier B.V. All rights reserved.

Shiogai Y.,Lancaster University | Stefanovska A.,Lancaster University | Stefanovska A.,University of Ljubljana | McClintock P.V.E.,Lancaster University
Physics Reports | Year: 2010

The application of methods drawn from nonlinear and stochastic dynamics to the analysis of cardiovascular time series is reviewed, with particular reference to the identification of changes associated with ageing. The natural variability of the heart rate (HRV) is considered in detail, including the respiratory sinus arrhythmia (RSA) corresponding to modulation of the instantaneous cardiac frequency by the rhythm of respiration. HRV has been intensively studied using traditional spectral analyses, e.g. by Fourier transform or autoregressive methods, and, because of its complexity, has been used as a paradigm for testing several proposed new methods of complexity analysis. These methods are reviewed. The application of time-frequency methods to HRV is considered, including in particular the wavelet transform which can resolve the time-dependent spectral content of HRV. Attention is focused on the cardio-respiratory interaction by introduction of the respiratory frequency variability signal (RFV), which can be acquired simultaneously with HRV by use of a respiratory effort transducer. Current methods for the analysis of interacting oscillators are reviewed and applied to cardio-respiratory data, including those for the quantification of synchronization and direction of coupling. These reveal the effect of ageing on the cardio-respiratory interaction through changes in the mutual modulation of the instantaneous cardiac and respiratory frequencies. Analyses of blood flow signals recorded with laser Doppler flowmetry are reviewed and related to the current understanding of how endothelial-dependent oscillations evolve with age: the inner lining of the vessels (the endothelium) is shown to be of crucial importance to the emerging picture. It is concluded that analyses of the complex and nonlinear dynamics of the cardiovascular system can illuminate the mechanisms of blood circulation, and that the heart, the lungs and the vascular system function as a single entity in dynamical terms. Clear evidence is found for dynamical ageing. © 2009 Elsevier B.V.

Borut K.,Oncology and Radiotherapy Institute | Lijana Z.-K.,University of Ljubljana
Radiotherapy and Oncology | Year: 2012

Tolerability to gemcitabine radiochemotherapy was evaluated in 33 patients with inoperable, locally advanced transitional-cell bladder cancers. The dose of 75 mg/m 2 gemcitabine once a week, concurrently with standard radiotherapy of 60 Gy/6 weeks, was found to be acceptable. Eighty-one percentage of 3-year local progression-free survival suggests efficiency warranting further studies. © 2011 Elsevier Ireland Ltd. All rights reserved.

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.

Luzar B.,University of Ljubljana | Calonje E.,St Johns Institute Of Dermatology
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.

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.

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.

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.

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.

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.

Vidic A.D.,University of Ljubljana
International Journal of Engineering Education | Year: 2011

In this comparative study, we examined the level of basic discipline knowledge and problem-solving abilities in problem-based learning (PBL), incorporated into a traditional curriculum in an introductory statistics course. Progressively less structured, less familiar and more open problems were presented to engineering students. Engineering problems triggered the learning of new statistical contents and activated small group problem solving. Students as a group determined the learning goals, individually searched for information, and together analysed the information collected. Such a problem-solving process with real-world problemsis often seen as unstructured and time-consuming. Anexperiment was carried out to find out whether this approach yields adequate basic statistical knowledge and improves problem solving. Two randomised groups of students from the same engineering programme were compared: one group used PBL and the other followed the traditional method of instruction. The results of statistical analysis showed that engineering students with the PBL approach acquired sufficient basic statistical knowledge and were better able to solve statistical problems from the field of engineering than the students who followed the traditional way of instruction. Some characteristics of the implementation of the course are discussed, as well as some limitations of the study. © 2011 TEMPUS Publications.

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.

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.

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.

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.

Batista M.,University of Ljubljana
International Journal of Mechanical Sciences | Year: 2016

In this article, an analytical solution for the deflection of a Reissner's beam under a force acting at the midpoint between two supports is given. Three types of beams are considered: simply supported, roller supported, and hinge supported. The solution for each type is illustrated by load-deflection diagrams, tables of reference values, and examples of deformed beam shapes. © 2016 Elsevier Ltd. All rights reserved.

Mervic L.,University of Ljubljana
Acta Dermatovenerologica Alpina, Pannonica et Adriatica | Year: 2012

The clinical and histopathological characteristics that predict the outcomes of patients with melanoma have been studied for more than four decades. Increasingly more melanoma patients are being included in prospectively collected databases and our understanding of the biology of melanoma is improving. Therefore, the melanoma staging system is constantly being revised. The currently valid American Joint Committee on Cancer (AJCC) staging system for melanoma has been in place since early 2010 and is crucial for the determination of appropriate treatment, follow-up, and evaluating the risk of recurrence. Staging of a localized primary melanoma is based on the histopathological characteristics of the tumor: Breslow tumor thickness, mitotic rate, and presence or absence of ulceration. The Clark level of invasion is no longer recommended as a staging criterion. When mitotic rate is taken into consideration, it is no longer an independent prognostic factor. Other important and independent adverse predictors of primary cutaneous melanoma survival that are not part of the AJCC staging system are the age and sex of the patient and the anatomic location of the primary tumor. These factors, combined with the melanoma's histopathological features, could predict an individual patient's prognosis more precisely than the AJCC staging system currently in use.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

Rubbers are commonly used in industry to reduce vibration transfer and, consequently, reduce structural noise. The vibration transfer through rubber can be modelled with finite elements; however, to achieve satisfactory results it is necessary to know the viscoelastic properties of the rubber. This paper describes the commonly used theory of vibration transmission through rubber modelled as a single-degree-of-freedom (SDOF) system. Three simplified rubber models are used to identify the constant Young's modulus and damping factor from the measurements of two different rubber specimens, and with the obtained results the theoretical transmissibilities are calculated. The frequency-dependent Young's modulus and damping factor are also calculated from measurements. The practical use of previous measurements of dynamic material properties is presented in a finite-element analysis, where three different definitions of the dynamic material properties are carried out for four different rubber specimens, which corresponds to 12 analyses. The finite-element analyses are then compared with the measurements, and general guidelines for using dynamic material properties in ansys Workbench v.14 are given. © 2013, Society for Experimental Mechanics.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

Ilievski E.,University of Amsterdam | De Nardis J.,University of Amsterdam | Wouters B.,University of Amsterdam | Caux J.-S.,University of Amsterdam | And 2 more authors.
Physical Review Letters | Year: 2015

In integrable many-particle systems, it is widely believed that the stationary state reached at late times after a quantum quench can be described by a generalized Gibbs ensemble (GGE) constructed from their extensive number of conserved charges. A crucial issue is then to identify a complete set of these charges, enabling the GGE to provide exact steady-state predictions. Here we solve this long-standing problem for the case of the spin-1/2 Heisenberg chain by explicitly constructing a GGE which uniquely fixes the macrostate describing the stationary behavior after a general quantum quench. A crucial ingredient in our method, which readily generalizes to other integrable models, are recently discovered quasilocal charges. As a test, we reproduce the exact postquench steady state of the Néel quench problem obtained previously by means of the Quench Action method. © 2015 American Physical Society.

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.

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.

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.

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.

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.

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.

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.

Zitko R.,Jozef Stefan Institute | Zitko R.,University of Ljubljana | Pruschke T.,University of Gottingen
New Journal of Physics | Year: 2010

We study the effects of the exchange interaction between an adsorbed magnetic atom with easy-axis magnetic anisotropy and the conductionband electrons from the substrate. We model the system using an anisotropic Kondo model and we compute the impurity spectral function, which is related to the differential conductance (dI/dV) spectra measured using a scanning tunneling microscope. To make contact with the known experimental results for iron atoms on the CuN/Cu(100) surface (Hirjibehedin et al 2007 Science 317 1199), we calculated the spectral functions in the presence of an external magnetic field of varying strength applied along all three spatial directions. It is possible to establish an upper bound on the coupling constant J: in the range of the magnetic fields for which the experimental results are currently known (up to 7 T), the low-energy features in the calculated spectra agree well with the measured dI/dV spectra if the exchange coupling constant J is at most half as large as that for cobalt atoms on the same surface. We show that for an even higher magnetic field (between 8 and 9 T) applied along the 'hollow direction', the impurity energy states cross, giving rise to a Kondo effect which takes the form of a zero-bias resonance. The coupling strength J could be determined experimentally by performing tunneling spectroscopy in this range of magnetic fields. On the technical side, the paper introduces an approach for calculating the expectation values of global spin operators and all the components of the impurity magnetic susceptibility tensor (including the out-of-diagonal ones) in numerical renormalization group (NRG) calculations with no spin symmetry. An appendix contains a density functional theory (DFT) study of the Co and Fe adsorbates on the CuN/Cu(100) surface: we compare magnetic moments, as well as orbital energies, occupancies, centers and spreads, by calculating the maximally localized Wannier orbitais of the adsorbates. © IOP Publishing Ltd and Deutsche Physikalische Gesellschaft.

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.

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.

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.

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.

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.

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.

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.

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.

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.

Trkman P.,University of Ljubljana | McCormack K.,DRK Research A Practitioner Oriented Research Organization
IEEE Transactions on Engineering Management | Year: 2010

In recent years, organizations have invested heavily in e-procurement technology solutions. However, an estimation of the value of the technology-enabled procurement process is often lacking. Our paper presents a rigorous methodological approach to the analysis of e-procurement benefits. Business process simulations are used to analyze the benefits of both technological and organizational changes related to e-procurement. The approach enables an estimation of both the average and variability of procurement costs and benefits, workload, and lead times. In addition, the approach enables optimization of a procurement strategy (e.g., approval levels). Finally, an innovative approach to estimation of value at risk is shown. © 2010 IEEE.

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.

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.

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.

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.

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.

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.

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.

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.

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.

Mankoc Borstnik N.S.,University of Ljubljana
Physical Review D - Particles, Fields, Gravitation and Cosmology | Year: 2015

The spin-charge-family theory [1-13], in which spinors, besides the Dirac spin, also carry the second kind of Clifford object - no charges - is a type of Kaluza-Klein theory [14]. The Dirac spinors of one Weyl representation in d=(13+1) manifest [1,3,4,10,13,15] in d=(3+1) at low energies all of the properties of quarks and leptons assumed by the standard model. The second kind of spin explains the origin of families. Spinors interact with the vielbeins and the two kinds of spin connection fields, the gauge fields of the two kinds of Clifford objects, which, besides the gravity and known gauge vector fields, manifest in d=(3+1) also several scalar gauge fields. Scalars with the space index s∈(7,8) carry the weak charge and the hypercharge (12,±12, respectively), thereby explaining the origin of the Higgs and Yukawa couplings. It is demonstrated in this paper that the scalar fields with the space index t∈(9,10,⋯,14) carry the triplet color charges, causing transitions of antileptons and antiquarks into quarks and back, thus enabling the appearance and the decay of baryons. These scalar fields show themselves in the presence of the right-handed neutrino condensate, which breaks the CP symmetry, the answer to the question about matter-antimatter asymmetry. © 2015 American Physical Society.

Prelovsek S.,University of Ljubljana | Prelovsek S.,Jozef Stefan Institute | Lang C.B.,University of Graz | Leskovec L.,Jozef Stefan Institute | Mohler D.,Fermi National Accelerator Laboratory
Physical Review D - Particles, Fields, Gravitation and Cosmology | Year: 2015

Recently experimentalists have discovered several charged charmoniumlike hadrons Zc+ with unconventional quark content c¯cd¯u. We perform a search for Zc+ with mass below 4.2 GeV in the channel IG(JPC)=1+(1+-) using lattice QCD. The major challenge is presented by the two-meson states J/ψπ, ψ2Sπ, ψ1Dπ, DD¯∗, D∗D¯∗, ηcρ that are inevitably present in this channel. The spectrum of eigenstates is extracted using a number of meson-meson and diquark-antidiquark interpolating fields. For our pion mass of 266 MeV we find all the expected two-meson states but no additional candidate for Zc+ below 4.2 GeV. Possible reasons for not seeing an additional eigenstate related to Zc+ are discussed. We also illustrate how a simulation incorporating interpolators with a structure resembling low-lying two-meson states seems to render a Zc+ candidate, which is however not robust after further two-meson states around 4.2 GeV are implemented. © 2015 American Physical Society.

Marinsek M.,University of Ljubljana
Boletin de la Sociedad Espanola de Ceramica y Vidrio | Year: 2011

Carbon deposition on various Ni-YSZ catalytic composites with average Ni particle size from 0.44 μm to 0.98 mm was studied under dry CH4-Ar and humidified CH4-Ar conditions. The change in the catalytic activity was monitored both as a mass gain due to carbon deposition and hydrogen evolution due to CH4 dehydrogenation on Ni-YSZ. Regarding the start of methane decomposition and subsequent catalyst deactivation rate, composites with smaller Ni-grains were much more active in comparison to those with relatively large grains. Dry methane conditions always caused coking of the catalyst substrate with substantial activity loss. In contrast, under humidified methane atmosphere conditions with a steam to carbon (S/C) ratio of 0.82, catalytic activity of the Ni-YSZ composites remained nearly undiminished after 2,000 minutes at chosen deposition temperatures (600-800 °C). On the catalyst surface, some encapsulation of Ni with the deposited carbon was noticed while carbon filaments grew inside the treated samples. The dimensions of C-filaments were influenced by treatment conditions and Ni-YSZ substrate morphology.

Cerovsek T.,University of Ljubljana
Advanced Engineering Informatics | Year: 2011

This study provides a review of important issues for 'Building Information Modelling' (BIM) tools and standards and comprehensive recommendations for their advancement and development that may improve BIM technologies and provide a basis for inter-operability, integration, model-based communication, and collaboration in building projects. Based on a critical review of Building Product Modelling, including the development of standards for exchange and the features of over 150 AEC/O (Architecture, Engineering, Construction, and Operation) tools and digital models, a methodological framework is proposed for improvements to both BIM tools and schemata. The features relevant to the framework were studied using a conceptual process model and a 'BIM System-of-Systems' (BIM-SoS) model. The development, implementation, and use of the BIM Schema are analysed from the standpoint of standardisation. The results embrace the requirements for a BIM research methodology, with an example of methods and procedures, an R&D review with critique, and a multi-standpoint framework for developments with concrete recommendations, supported by BIM metrics, upon which the progress of tools, models, and standards may be measured, evaluated, streamlined, and judged. It is also proposed that any BIM Schema will never be 'completed' but should be developed as evolutionary ontology by 'segmented standpoint models' to better account for evolving tools and AEC/O practices. © 2010 Elsevier Ltd. All rights reserved.

Vodopivec-Jamsek V.,University of Ljubljana
Cochrane database of systematic reviews (Online) | Year: 2012

Preventive health care promotes health and prevents disease or injuries by addressing factors that lead to the onset of a disease, and by detecting latent conditions to reduce or halt their progression. Many risk factors for costly and disabling conditions (such as cardiovascular diseases, cancer, diabetes, and chronic respiratory diseases) can be prevented, yet healthcare systems do not make the best use of their available resources to support this process. Mobile phone messaging applications, such as Short Message Service (SMS) and Multimedia Message Service (MMS), could offer a convenient and cost-effective way to support desirable health behaviours for preventive health care. To assess the effects of mobile phone messaging interventions as a mode of delivery for preventive health care, on health status and health behaviour outcomes. We searched: the Cochrane Central Register of Controlled Trials (CENTRAL, The Cochrane Library 2009, Issue 2), MEDLINE (OvidSP) (January 1993 to June 2009), EMBASE (OvidSP) (January 1993 to June 2009), PsycINFO (OvidSP) (January 1993 to June 2009), CINAHL (EbscoHOST) (January 1993 to June 2009), LILACS (January 1993 to June 2009) and African Health Anthology (January 1993 to June 2009).We also reviewed grey literature (including trial registers) and reference lists of articles. We included randomised controlled trials (RCTs), quasi-randomised controlled trials (QRCTs), controlled before-after (CBA) studies, and interrupted time series (ITS) studies with at least three time points before and after the intervention. We included studies using SMS or MMS as a mode of delivery for any type of preventive health care. We only included studies in which it was possible to assess the effects of mobile phone messaging independent of other technologies or interventions. Two review authors independently assessed all studies against the inclusion criteria, with any disagreements resolved by a third review author. Study design features, characteristics of target populations, interventions and controls, and results data were extracted by two review authors and confirmed by a third author. Primary outcomes of interest were health status and health behaviour outcomes. We also considered patients' and providers' evaluation of the intervention, perceptions of safety, health service utilisation and costs, and potential harms or adverse effects. Because the included studies were heterogeneous in type of condition addressed, intervention characteristics and outcome measures, we did not consider that it was justified to conduct a meta-analysis to derive an overall effect size for the main outcome categories; instead, we present findings narratively. We included four randomised controlled trials involving 1933 participants.For the primary outcome category of health, there was moderate quality evidence from one study that women who received prenatal support via mobile phone messages had significantly higher satisfaction than those who did not receive the messages, both in the antenatal period (mean difference (MD) 1.25, 95% confidence interval (CI) 0.78 to 1.72) and perinatal period (MD 1.19, 95% CI 0.37 to 2.01). Their confidence level was also higher (MD 1.12, 95% CI 0.51 to 1.73) and anxiety level was lower (MD -2.15, 95% CI -3.42 to -0.88) than in the control group in the antenatal period. In this study, no further differences were observed between groups in the perinatal period. There was low quality evidence that the mobile phone messaging intervention did not affect pregnancy outcomes (gestational age at birth, infant birth weight, preterm delivery and route of delivery).For the primary outcome category of health behaviour, there was moderate quality evidence from one study that mobile phone message reminders to take vitamin C for preventive reasons resulted in higher adherence (risk ratio (RR) 1.41, 95% CI 1.14 to 1.74). There was high quality evidence from another study that participants receiving mobile phone messaging support had a significantly higher likelihood of quitting smoking than those in a control group at 6 weeks (RR 2.20, 95% CI 1.79 to 2.70) and at 12 weeks follow-up (RR 1.55, 95% CI 1.30 to 1.84). At 26 weeks, there was only a significant difference between groups if, for participants with missing data, the last known value was carried forward.

Znidaric M.,University of Ljubljana
Physical Review B - Condensed Matter and Materials Physics | Year: 2013

We study magnetization transport at infinite temperature in several spin ladder systems as well as in next-nearest-neighbor coupled spin chains. In the integrable ladder considered we analytically show that the transport is ballistic in sectors with nonzero average magnetization, while numerical simulations of a nonequilibrium stationary setting indicate an anomalous transport in the zero-magnetization sector. For other systems, isotropic Heisenberg ladder and spin chains, showing eigenlevel repulsion typical of quantum chaotic systems, numerical simulations indicate diffusive transport. © 2013 American Physical Society.

Zupancic M.,University of Ljubljana | Kavcic T.,University of Primorska
Journal of Adolescence | Year: 2014

The role of personality traits in 674 emerging adult students' (aged 18 to 28; 80% female) individuation in relation to parents was investigated cross-sectionally. Self-reports were obtained by the Big Five Inventory and the Individuation Test for Emerging Adults. Personality was predictive of measures of individuation, over and above the students' background characteristics, suggesting that personality can be viewed as an inner resource shaping experiences of individuation. Agreeableness contributed to support seeking, and connectedness with both parents, and Extraversion predicted connectedness with mothers. Conscientiousness was related negatively to both perceptions of parental intrusiveness and fear of disappointing the mother, whereas Neuroticism was predictive of perceptions of maternal intrusiveness, and fear of disappointing the parents. Openness was associated with self-reliance in relationships with both parents, and demonstrated negative links with support seeking and connectedness with mothers. Few moderating effects of age and gender on Extraversion-individuation associations were revealed. © 2014 The Foundation for Professionals in Services for Adolescents.

Prosen T.,University of Ljubljana
Journal of Physics A: Mathematical and Theoretical | Year: 2015

We review recent progress on constructing non-equilibrium steady state density operators of boundary driven locally interacting quantum chains, where driving is implemented via Markovian dissipation channels attached to the chain's ends. We discuss explicit solutions in three different classes of quantum chains, specifically, the paradigmatic (anisotropic) Heisenberg spin- chain, the Fermi-Hubbard chain, and the Lai-Sutherland spin-1 chain, and discuss universal concepts which characterize these solutions, such as matrix product ansatz and a more structured walking graph state ansatz. The central theme is the connection between the matrix product form of nonequilibrium states and the integrability structures of the bulk Hamiltonian, such as the Lax operators and the Yang-Baxter equation. However, there is a remarkable distinction with respect to the conventional quantum inverse scattering method, namely addressing nonequilibrium steady state density operators requires non-unitary irreducible representations of Yang-Baxter algebra which are typically of infinite dimensionality. Such constructions result in non-Hermitian, and often also non-diagonalisable families of commuting transfer operators which in turn result in novel conservation laws of the integrable bulk Hamiltonians. For example, in the case of the anisotropic Heisenberg model, quasi-local conserved operators which are odd under spin reversal (or spin flip) can be constructed, whereas the conserved operators stemming from orthodox Hermitian transfer operators (via logarithmic differentiation) are all even under spin reversal. © 2015 IOP Publishing Ltd.

A computing environment for the seismic performance assessment of reinforced concrete frames has been developed in Matlab in combination with OpenSees. It includes several functions which provide calculations of the moment-rotation relationship of plastic hinges in columns and beams, rapid determination of simplified nonlinear structural models, the post-processing of the results of analyses and structural performance assessment with different methods. The user can add new functions to the PBEE toolbox in order to support additional procedures for the seismic performance assessment of RC frames, or can just change the rules for determining the moment-rotation relationship of plastic hinges in columns and beams, which are the main source of uncertainty in simplified nonlinear models. In the paper, the capabilities of the computing environment (PBEE toolbox) are first explained by focusing on the procedures for determining the moment-rotation relationship of plastic hinges. Different examples are then presented, starting with a comparison between the calculated response of a four-storey RC frame building and the response obtained in a pseudo-dynamic experiment. The calculated response was determined with the two different structural models which are later on used for the demonstration of the seismic performance assessment of the same structure by the N2 method. Lastly, seismic performance assessment of an eight-storey frame is performed by using incremental dynamic analysis with consideration of the modelling uncertainties. © 2010 Springer Science+Business Media B.V.

Pusavec F.,University of Ljubljana
International Journal of Refractory Metals and Hard Materials | Year: 2012

This experimental study focuses on high performance cryogenic machining of porous tungsten, which is classified as a difficult-to-machine material, where the quality of the machined surface porosity is one of the most important objectives. For achieving the required post-machining porosity and surface roughness, the optimum machining parameters and tool grade, as well as cryogenic machining method, an alternative to conventional machining, were chosen. For smearing evaluation, pores on the machined surface are individually analyzed from SEM pictures. Different tool grades (uncoated carbide, ceramic, polycrystalline diamond and cubic boron nitride) are analyzed in this study. A precise correlation between the performance measures and the machining parameters, including tool grade, is developed to achieve the required performance measures. Surface roughness, porosity, tool-wear and cutting forces are measured and analyzed. A performance-based multi-objective optimization model is developed based on genetic algorithms (GA) and is used to predict the optimal cutting parameters for achieving improved machining performance. © 2012 Elsevier Ltd. All rights reserved.

Isidori G.,CERN | Isidori G.,National Institute of Nuclear Physics, Italy | Kamenik J.F.,Jozef Stefan Institute | Kamenik J.F.,University of Ljubljana
Physical Review Letters | Year: 2012

Recent evidence for direct CP violation in nonleptonic charm decays cannot be easily accommodated within the standard model. On the other hand, it fits well in new physics models generating CP violating ΔC=1 chromomagnetic dipole operators. We show that in these frameworks sizable direct CP asymmetries in radiative D→P +P -γ decays (P=π, K), with M PP close to the ρ or the peak, can be expected. Enhanced matrix elements of the electromagnetic dipole operators can partly compensate the long distance dominance in these decays, leading to CP asymmetries of the order of several percent. If observed at this level, these would provide a clean signal of physics beyond the standard model and of new dynamics associated with dipole operators. We briefly comment on related CP violating observables accessible via time dependent D(D̄)→P +P -γ studies and angular decay product distributions in rare semileptonic D decays. © 2012 American Physical Society.

Crossman R.J.,Durham University | Skulj D.,University of Ljubljana
International Journal of Approximate Reasoning | Year: 2010

We consider convergence of Markov chains with uncertain parameters, known as imprecise Markov chains, which contain an absorbing state. We prove that under conditioning on non-absorption the imprecise conditional probabilities converge independently of the initial imprecise probability distribution if some regularity conditions are assumed. This is a generalisation of a known result from the classical theory of Markov chains by Darroch and Seneta [6]. Crown Copyright © 2010 Published by Elsevier Inc. All rights reserved.

Golez D.,Jozef Stefan Institute | Zitko R.,Jozef Stefan Institute | Zitko R.,University of Ljubljana
Physical Review B - Condensed Matter and Materials Physics | Year: 2013

We establish the low-temperature phase diagrams of the spin-1/2 and spin-1 Kondo lattice models as a function of the conduction-band filling n and the exchange coupling strength J in the regime of ferromagnetic effective exchange interactions (n≲0.5, J/D≳2). We show that both models have several distinct ferromagnetic phases separated by continuous Lifshitz transitions of the Fermi-pocket vanishing or emergence type: one of the phases has a true gap in the minority band (half metal with magnetization rigidity), the others only a pseudogap. The spin-1/2 model has the half-metal phase, two topologically different pseudogap phases, and a paramagnetic state for very large J. The spin-1 model has the half-metal phase and a single pseudogap phase with an electron pocket. We find that, quite generically, ferromagnetism and Kondo screening coexist rather than compete both in spin-1/2 and spin-1 models. We establish the hysteretic behavior of the systems in an external magnetic field: spin-flop transitions preempt further Lifshitz transitions at finite magnetic field. We establish a "ferromagnetic Doniach diagram": in the spin-1/2 model the Curie temperature peaks near J/D≈1.2 and goes to zero, while in the spin-1 model it saturates. © 2013 American Physical Society.

Dular M.,University of Ljubljana
Wear | Year: 2016

In the present study we show experimental campaign where cavitation erosion in water at different temperatures was investigated. In contrary to other studies, where cavitation is generated by ultrasound, we employed hydrodynamic cavitation, which more closely resembles the conditions in applications - it is known that the results obtained by ultrasonic cavitation can be misleading. The tests were performed in a radial flow test-section, which can generate very aggressive type of cavitation. Polished aluminum samples were used to investigate the damage. Temperatures in the range between 30 and 100 °C were investigated.We found out that the temperature of the water significantly influences the cavitation aggressiveness - maximum aggressiveness was found at 60 °C.In the last part of the work two theories were developed and tested. Micro-jet approach correctly predicted the trend but the influence of the temperature was marginal. On the other hand, the theory of the spherical bubble collapse with consideration of thermodynamic effects of cavitation produced a very good agreement to the experiments. © 2015.

Demsar J.,University of Ljubljana
Machine Learning | Year: 2010

Relief is a measure of attribute quality which is often used for feature subset selection. Its use in induction of classification trees and rules, discretization, and other methods has however been hindered by its inability to suggest subsets of values of discrete attributes and thresholds for splitting continuous attributes into intervals. We present efficient algorithms for both tasks. © The Author(s) 2009.

Topic M.D.,University of Ljubljana | Coakley J.,University of Chichester
Sociology of Sport Journal | Year: 2010

Sociology of sport knowledge on national identity is grounded in research that focuses primarily on long established nation-states with widely known histories. The relationship between sport and national identity in postsocialist/Soviet/colonial nations that have gained independence or sovereignty since 1990 has seldom been studied. This paper examines the role of sports in the formation of national identity in postsocialist Slovenia, a nation-state that gained independence in 1990. Our analysis focuses on the recent context in which the current but fluid relationship between sport and Slovenian national identity exists. Using Slovenia as a case study we identify seven factors that may moderate the effectiveness of sports as sites for establishing and maintaining national identity and making successful global identity claims in the twenty-first century. We conclude that these factors should be taken into account to more fully understand the sport-national identity relationship today, especially in new and developing nations. © 2010 Human Kinetics, Inc.

Savic M.,S2P D.o.o. | Gersak G.,University of Ljubljana
Measurement: Journal of the International Measurement Confederation | Year: 2015

The paper presents a procedure for evaluation of system for measuring electrodermal activity of the skin. The proposed procedure was tested within a metrological evaluation of a low-cost wireless system. The procedure consists of static calibration by comparison, dynamic evaluation by means of generated sine signals and testing for functionality using of a simple psychophysiological experiment. Additionally, the quality and reliability of measured data transmission is evaluated. A low cost, low weight, ergonomically shaped and battery powered wireless (ZigBee protocol) portable wrist-type measuring system was designed and built and the proposed procedure used to evaluate it. Based on the results of the evaluation acceptance criteria for a reliable skin conductance meter used for skin conductance levels studies could be proposed. Devices conforming to these criteria would be reliable and sufficiently accurate for skin conductance level measurements, with an established metrological traceability and readings linked to the basic units of the international system of units SI. © 2014 Elsevier Ltd. All rights reserved.

Bandmann V.,TU Darmstadt | Kreft M.,University of Ljubljana | Homann U.,TU Darmstadt
Molecular Plant | Year: 2011

To analyze the kinetics and size of single exo- and endocytotic events in BY-2 protoplasts, we employed cell-attached membrane capacitance measurements. These measurements revealed different modes of fusion and fission of single vesicles. In about half of the observed exocytotic events, fusion occurred transiently, which facilitates rapid recycling of vesicles. In addition, transient sequential or multi-vesicular exocytosis observed in some recordings can contribute to an increase in efficiency of secretory product release. Microscopic analysis of the timescale of cellulose and pectin deposition in protoplasts demonstrates that rebuilding of the cell wall starts soon after isolation of protoplasts and that transient fusion events can fully account for secretion of the required soluble material. The capacitance measurements also allowed us to investigate formation of the fusion pore. We speculate that regulation of secretion may involve control of the length and/or size of fusion pore opening. Together, the different kinetic modes of exo- and endocytosis revealed by capacitance measurements underline the complexity of this process in plants and provide a basis for future research into the underlying mechanisms. The fact that similar fusion/fission kinetics are present in plant and animal cells suggests that many of these mechanisms are highly conserved among eukaryotes. © 2010 The Author. Published by the Molecular Plant Shanghai Editorial Office in association with Oxford University Press on behalf of CSPP and IPPE, SIBS, CAS.

Rozman D.,University of Ljubljana | Monostory K.,Hungarian Academy of Sciences
Pharmacology and Therapeutics | Year: 2010

This review focuses on the non-statin strategies for the treatment of hyperlipidemias in humans. Even if statins remain the major hypolipidemic drugs at present, an increasing number of patients that are treated with statins raises as well the numbers of patients suffering from side effects or not responding well to the therapy. Thus, development of novel approaches to battle the world epidemics of hyperlipidemia remains relevant. The non-statin strategies include the decrease of cholesterol absorption from the diet, lowering the atherogenic lipoprotein release and increasing HDL levels, or increasing elimination of cholesterol by bile acid binding. Representative non-statin drugs that are on the market or are in development phases are described herein in comparison to statins. In addition to 3β-hydroxy-3-methylglutaryl coenzyme A reductase (HMGCR), as the major regulatory enzyme of cholesterol synthesis that is the target of statins, some other enzymes of this multi-step pathway represent perspective targets for the development of novel hypolipidemics. None of these inhibitors are currently approved for use in humans. We describe the characteristics of the later enzymes of cholesterol synthesis, starting from the squalene synthase step. Inhibitors of these enzymes are critically evaluated, particularly concerning safety in humans (teratogenic potential, toxicity, and other side effects) and their hypolipidemic effects compared to the statins. Since only a limited number of publications discuss the non-statin approaches for the treatment of hyperlipidemias, this review represents a valuable up-to date summary, with a take-home message, that novel approaches deserve more attention in the future, irrespective of the success of statins. © 2010 Elsevier Inc.

Zarnack K.,European Bioinformatics Institute | Konig J.,University of Cambridge | Tajnik M.,University of Cambridge | Tajnik M.,University of Ljubljana | And 10 more authors.
Cell | Year: 2013

There are ∼650,000 Alu elements in transcribed regions of the human genome. These elements contain cryptic splice sites, so they are in constant danger of aberrant incorporation into mature transcripts. Despite posing a major threat to transcriptome integrity, little is known about the molecular mechanisms preventing their inclusion. Here, we present a mechanism for protecting the human transcriptome from the aberrant exonization of transposable elements. Quantitative iCLIP data show that the RNA-binding protein hnRNP C competes with the splicing factor U2AF65 at many genuine and cryptic splice sites. Loss of hnRNP C leads to formation of previously suppressed Alu exons, which severely disrupt transcript function. Minigene experiments explain disease-associated mutations in Alu elements that hamper hnRNP C binding. Thus, by preventing U2AF65 binding to Alu elements, hnRNP C plays a critical role as a genome-wide sentinel protecting the transcriptome. The findings have important implications for human evolution and disease. © 2013 Elsevier Inc.

Drobne D.,University of Ljubljana
Methods in Molecular Biology | Year: 2013

Integration of a scanning electron microscope (SEM) and focused ion beam (FIB) technology into a single FIB/SEM system permits use of the FIB as a nano-scalpel to reveal site-specific subsurface microstructures which can be examined in great detail by SEM. The FIB/SEM technology is widely used in the semiconductor industry and material sciences, and recently its use in the life sciences has been initiated. Samples for FIB/SEM investigation can be either embedded in a plastic matrix, the traditional means of preparation of transmission electron microscopy (TEM) specimens, or simply dried as in samples prepared for SEM imaging. Currently, FIB/SEM is used in the life sciences for (a) preparation by the lift-out technique of lamella for TEM analysis, (b) tomography of samples embedded in a matrix, and (c) in situ site-specific FIB milling and SEM imaging using a wide range of magnifications. Site-specific milling and imaging has attracted wide interest as a technique in structural research of single eukaryotic and prokaryotic cells, small animals, and different animal tissue, but it still remains to be explored more thoroughly. In the past, preparation of samples for site-specific milling and imaging by FIB/SEM has typically adopted the embedding techniques used for TEM samples, and which have been very well described in the literature. Sample preparation protocols for the use of dried samples in FIB/SEM have been less well investigated. The aim of this chapter is to encourage application of FIB/SEM on dried biological samples. A detailed description of conventional dried sample preparation and FIB/SEM investigation of dried biological samples is presented. The important steps are described and illustrated, and direct comparison between embedded and dried samples of same tissues is provided. The ability to discover links between gross morphology of the tissue or organ, surface characteristics of any selected region, and intracellular structural details on the nanometer scale is an appealing application of electron microscopy in the life sciences and merits further exploration. © 2013 Springer Science+Business Media, LLC.

Tavcer P.F.,University of Ljubljana
Textile Research Journal | Year: 2010

Cotton fabric was bleached with equilibrium peracetic acid in an exhaustion process and in cold pad-batch, hot pad-batch, and pad-steam bleaching processes. Exhaustion bleaching proceeded for 40 minutes at 60 °C and pH 7.5 with different concentrations of Persan S15 (peracetic acid produced by Belinka, Slovenia). Pad-batch processes were conducted with storage for different times at room temperature or at 60 °C. Two bleaching baths with 15 and 60 ml/l of Persan S15 were used for the impregnation processes. Pad-steam bleaching was also performed; the samples were steamed immediately after padding with bleaching solution or after cold/hot storage. The degree of whiteness achieved with elongation of storage time was measured. The influence of different bleaching conditions on damage to the cotton fabrics was evaluated by measurements of the degree of polymerization and the breaking strength of the fabrics. It was established that the achieved whiteness values depend on the concentration of the bleaching agent, temperature, and time of treatment. The exhaustion bleaching and both types of pad-batch bleaching with low concentration bleaching solution are very convenient processes for bleaching of cotton fabric with peracetic acid. The pad-steam process did not prove appropriate. The breaking strength of the fabric did not deteriorate remarkably with any of the processes, but the degree of polymerization of the fibers revealed that damage occurred at high concentrations of bleaching agent. © The Author(s), 2010.

Macura M.,University of Ljubljana
Arthroscopy : the journal of arthroscopic & related surgery : official publication of the Arthroscopy Association of North America and the International Arthroscopy Association | Year: 2010

Rupture of the anterior cruciate ligament is a well-known entity and causes anteroposterior and rotational instability of an injured knee. Rupture of the medial patellofemoral ligament is less frequent, and its insufficiency causes patellar instability. Several techniques have been described for the reconstruction of each ligament. The 2 lesions and following instabilities can coexist, and both ligaments can be reconstructed simultaneously. We report on 2 cases, 1 recreational sportswoman and 1 high-level sportswoman, with coexisting lesions treated surgically by a single-step procedure using ipsilateral graft of the quadriceps tendon for reconstruction of medial patellofemoral ligament and anterior cruciate ligament. The advantage of this procedure is that there is only 1 donor site, and thus lower donor-site morbidity, while the strength of either neoligament is not sacrificed. The technique is described here. 2010 Arthroscopy Association of North America. Published by Elsevier Inc. All rights reserved.

Hebert-Losier K.,Mid Sweden University | Supej M.,University of Ljubljana | Holmberg H.-C.,Mid Sweden University
Sports Medicine | Year: 2014

Background: Alpine ski racing is a popular international winter sport that is complex and challenging from physical, technical, and tactical perspectives. Despite the vast amount of scientific literature focusing on this sport, including topical reviews on physiology, ski-snow friction, and injuries, no review has yet addressed the biomechanics of elite alpine ski racers and which factors influence performance. In World Cup events, winning margins are often mere fractions of a second and biomechanics may well be a determining factor in podium place finishes. Objective: The aim of this paper was to systematically review the scientific literature to identify the biomechanical factors that influence the performance of elite alpine ski racers, with an emphasis on slalom, giant slalom, super-G, and downhill events. Methods: Four electronic databases were searched using relevant medical subject headings and key words, with an additional manual search of reference lists, relevant journals, and key authors in the field. Articles were included if they addressed human biomechanics, elite alpine skiing, and performance. Only original research articles published in peer-reviewed journals and in the English language were reviewed. Articles that focused on skiing disciplines other than the four of primary interest were excluded (e.g., mogul, ski-cross and freestyle skiing). The articles subsequently included for review were quality assessed using a modified version of a validated quality assessment checklist. Data on the study population, design, location, and findings relating biomechanics to performance in alpine ski racers were extracted from each article using a standard data extraction form. Results: A total of 12 articles met the inclusion criteria, were reviewed, and scored an average of 69 ± 13 % (range 40-89 %) upon quality assessment. Five of the studies focused on giant slalom, four on slalom, and three on downhill disciplines, although these latter three articles were also relevant to super-G events. Investigations on speed skiing (i.e., downhill and super-G) primarily examined the effect of aerodynamic drag on performance, whereas the others examined turn characteristics, energetic principles, technical and tactical skills, and individual traits of high-performing skiers. The range of biomechanical factors reported to influence performance included energy dissipation and conservation, aerodynamic drag and frictional forces, ground reaction force, turn radius, and trajectory of the skis and/or centre of mass. The biomechanical differences between turn techniques, inter-dependency of turns, and abilities of individuals were also identified as influential factors in skiing performance. In the case of slalom and giant slalom events, performance could be enhanced by steering the skis in such a manner to reduce the ski-snow friction and thereby energy dissipated. This was accomplished by earlier initiation of turns, longer path length and trajectory, earlier and smoother application of ground reaction forces, and carving (rather than skidding). During speed skiing, minimizing the exposed frontal area and positioning the arms close to the body were shown to reduce the energy loss due to aerodynamic drag and thereby decrease run times. In actual races, a consistently good performance (i.e., fast time) on different sections of the course, terrains, and snow conditions was a characteristic feature of winners during technical events because these skiers could maximize gains from their individual strengths and minimize losses from their respective weaknesses. Limitations: Most of the articles reviewed were limited to investigating a relatively small sample size, which is a usual limitation in research on elite athletes. Of further concern was the low number of females studied, representing less than 4 % of all the subjects examined in the articles reviewed. In addition, although overall run time is the ultimate measure of performance in alpine ski racing, several other measures of instantaneous performance were also employed to compare skiers, including the aerodynamic drag coefficient, velocity, section time, time lost per change in elevation, and mechanical energy behaviours, which makes cross-study inferences problematic. Moreover, most studies examined performance through a limited number of gates (i.e., 2-4 gates), presumably because the most commonly used measurement systems can only capture small volumes on a ski field with a reasonable accuracy for positional data. Whether the biomechanical measures defining high instantaneous performance can be maintained throughout an entire race course remains to be determined for both male and female skiers. Conclusions: Effective alpine skiing performance involves the efficient use of potential energy, the ability to minimize ski-snow friction and aerodynamic drag, maintain high velocities, and choose the optimal trajectory. Individual tactics and techniques should also be considered in both training and competition. To achieve better run times, consistency in performance across numerous sections and varied terrains should be emphasized over excellence in individual sections and specific conditions. © 2013 Springer International Publishing Switzerland.

Mihalic T.,University of Ljubljana
Journal of Cleaner Production | Year: 2015

Despite several decades of academic and practical debate on tourism sustainability, its application in practice remains difficult. The dominant tourism discourse on sustainability (theory, seen as a concept) and responsibility (practice, understood as appropriate action) calls for a solid understanding of the process of how a responsible destination actually implements a sustainability agenda, which this paper aims to provide. In this context, we explore theoretical perspectives from political economics and behavioural economics to offer a well-reasoned integrated sustainability-responsibility model comprising three stages: Awareness, Agenda and Action. This Triple-A Model complements the sustainability indicators debate and provides advice on how to continuously implement the sustainability concept and move from market-value-led and environmentally laissez-faire tourism towards more environmental- and social-value-driven responsible tourism. In addition, this paper discusses the existing sustainability and responsibility nomenclatures and their use and contributes relevant conclusions on the current understanding of sustainability and responsibility in European and UNWTO practices. The term responsustable tourism is suggested to join two existing terms and demonstrate that the current understanding of responsible tourism behaviour is based on the concept of sustainable tourism. © 2014 The Author.

Vehovec T.,Krka D.d. | Obreza A.,University of Ljubljana
Journal of Chromatography A | Year: 2010

Recently a new detection method, based upon aerosol charging (the charged aerosol detector (CAD)) has been introduced as an alternative to evaporative light-scattering detector (ELSD), chemiluminescent nitrogen detector and refractive index detector for detection of non-ultraviolet and weakly ultraviolet active compounds and for UV-absorbing compounds in the absence of standards. The content of this review article includes description of operation principle, advantages and disadvantages of CAD system, and short reports of selected applications of this detector. The main advantages of CAD detector are unique performance characteristics: better sensitivity than ELSD system, a dynamic range of up to 4 orders of magnitude, ease of use and constancy of response factors. Both detectors are mass dependent and the response generated does not depend on the spectral or physicochemical properties of the analyte. This attractive feature of a detection technique generating universal response factors is the potential use of a single, universal standard for calibration against which all other compounds or impurities can be qualified. CAD also has the same limitation as ELSD, namely, the response is affected by mobile-phase composition. This problem has been resolved by using inverse gradient compensation as is done for high pressure liquid chromatography and supercritical fluid chromatography. CAD has been applied for the analysis of structurally diverse compounds used in the pharmaceutical, chemical, food, and consumer products industries and in life science research. They include nonvolatile and semivolatile neutral, acidic, basic, and zwitterionic compounds, both polar and nonpolar (e.g. lipids, proteins, steroids, polymers, carbohydrates, peptides). © 2010 Elsevier B.V. All rights reserved.

Dysregulation of nucleotide-binding oligomerization domains 1 and 2 (NOD1 and NOD2) has been implicated in the pathology of various inflammatory disorders, rendering them and their downstream signaling proteins potential therapeutic targets. Selective inhibition of NOD1 and NOD2 signaling could be advantageous in treating many acute and chronic diseases; therefore, harnessing the full potential of NOD inhibitors is a key topic in medicinal chemistry. Although they are among the best studied NOD-like receptors (NLRs), the therapeutic potential of pharmacological modulation of NOD1 and NOD2 is largely unexplored. This review is focused on the scientific progress in the field of NOD inhibitors over the past decade, including the recently reported selective inhibitors of NOD1 and NOD2. In addition, the potential approaches to inhibition of NOD signaling as well as the advantages and disadvantages linked with inhibition of NOD signaling are discussed. Finally, the potential directions for drug discovery are also discussed. © 2014 American Chemical Society.

Urbic T.,University of Ljubljana
Journal of Chemical Physics | Year: 2013

Monte Carlo simulations and integral equation theory were used to study the thermodynamics and structure of particles interacting through the smooth version of Stell-Hemmer interaction. We checked the possibility that a fluid with a core-softened potential reproduces anomalies of liquid water such as the density anomaly, the minimum in the isothermal compressibility as a function of temperature, and others. Critical points of the fluid were also determined. We showed that a potential with two characteristic distances is sufficient for the system to exhibit water-like behavior and anomalies, including the famous density maximum. We also showed that some versions of the integral equation theory completely fail to predict structure of such system, while others only predict it qualitatively. © 2013 AIP Publishing LLC.

Rutherford M.A.,University of Gottingen | PangrSic T.,University of Gottingen | PangrSic T.,University of Ljubljana
Cell Calcium | Year: 2012

Hair cells mediate our senses of hearing and balance by synaptic release of glutamate from somatic active zones (AZs). They share conserved mechanisms of exocytosis with neurons and other secretory cells of diverse form and function. Concurrently, AZs of these neuro-epithelial hair cells employ several processes that differ remarkably from those of neuronal synaptic terminals of the brain. Their unique molecular anatomy enables them to better respond to small, graded changes in membrane potential and to produce unsurpassed rates of exocytosis. Here, we focus on the AZs of cochlear inner hair cells (IHCs). As in other hair cells, these AZs are occupied by a cytoplasmic extension of the presynaptic density, called the synaptic ribbon: a specialized protein complex required for normal physiological function. Some proteins found at IHC synapses are uniquely expressed or enriched there, where their disruption can beget deafness in humans and in animal models. Other proteins, essential for regulation of conventional neuronal Ca2+-triggered fusion, are apparently absent from IHCs. Certain common synaptic proteins appear to have extra significance at ribbon-type AZs because of their interactions with unique molecules, their unusual concentrations, or their atypical localization and regulation. We summarize the molecular-anatomical specializations that underlie the unique synaptic physiology of hair cells. © 2012 Elsevier Ltd.

Dorner I.,University of Sarajevo | Dorner I.,University Paris - Sud | Fajfer S.,University of Ljubljana | Konik N.,Jozef Stefan Institute
Physical Review D - Particles, Fields, Gravitation and Cosmology | Year: 2012

We list scalar leptoquarks which mediate proton decay via renormalizable couplings to the standard model fermions. We employ a general basis of baryon number violating operators to parametrize contributions of each leptoquark towards proton decay. This then sets the stage for investigation of bounds on the leptoquark couplings to fermions with respect to the most current Super Kamiokande results on proton stability. We quantify if, and when, it is necessary to have leptoquark masses close to a scale of grand unification in the realistic SU(5) and flipped SU(5) frameworks. The most and the least conservative lower bounds on the leptoquark masses are then presented. We furthermore single out a leptoquark without phenomenologically dangerous tree-level exchanges which might explain discrepancy of the forward-backward asymmetries in tt̄ production observed at Tevatron, if relatively light. The same state could also play a significant role in explaining muon anomalous magnetic moment. We identify contributions of this leptoquark to dimension-six operators, mediated through a box diagram, and tree-level dimension-nine operators, which would destabilize the proton if sizable leptoquark and diquark couplings were to be simultaneously present. © 2012 American Physical Society.

Leskovec L.,Jozef Stefan Institute | Prelovsek S.,Jozef Stefan Institute | Prelovsek S.,University of Ljubljana
Physical Review D - Particles, Fields, Gravitation and Cosmology | Year: 2012

We derive the relation between the scattering phase shift and the two-particle energy in the finite box, which is relevant for extracting the strong phase shifts in lattice QCD. We consider elastic scattering of two particles with different mass and with nonzero total momentum in the lattice frame. This is a generalization of the Lüscher formula, which considers zero total momentum, and a generalization of Rummukainen-Gottlieb's formula, which considers degenerate particles with nonzero total momentum. We focus on the most relevant total momenta in practice, i.e. P=(2π/L)e z and P=(2π/L)(e x+e y), including their multiples and permutations. We find that the P-wave phase shift can be reliably extracted from the two-particle energy if the phase shifts for l2 can be neglected, and we present the corresponding relations. The reliable extraction of the S-wave phase shift is much more challenging since δ l=0 is always accompanied by δ l=1 in the phase shift relations, and we propose strategies for estimating δ l=0. We also propose the quark-antiquark and meson-meson interpolators that transform according the considered irreducible representations. © 2012 American Physical Society.

Kamenik J.F.,Jozef Stefan Institute | Kamenik J.F.,University of Ljubljana | Smith C.,University Claude Bernard Lyon 1
Physical Review D - Particles, Fields, Gravitation and Cosmology | Year: 2012

The impact a new neutral light particle of spin 0, 1/2, 1, or 3/2 could have on the tiny width of a light Higgs boson is systematically analyzed. To this end, we include all the relevant effective interactions, whether renormalizable or not, and review the possible signatures in the Higgs decay modes with missing energy. This includes the fully invisible Higgs boson decay, as well as modes with standard model gauge bosons or fermions in the final state. In many cases, simply preventing these modes from being dominant suffices to set tight model-independent constraints on the masses and couplings of the new light states. © 2012 American Physical Society.

Likozar B.,Polymer Competence Center Leoben | Likozar B.,University of Ljubljana
Soft Matter | Year: 2011

In order to achieve good morphological, mechanical, structural, and thermal properties of a polymer electrolyte, ionic-liquid-in-polymer electrolytes have been explored. It was found that 1-ethyl-3-methylimidazolium, 1-butyl-3-methylimidazolium, and 1-butyl-1-methylpyrrolidinium tetrafluoroborate (EMImBF 4, BMImBF 4, and BMPyBF 4), hexafluorophosphate (EMImPF 6, BMImPF 6, and BMPyPF 6), and bis(trifluoromethylsulfonyl)imide (EMImTFSI, BMImTFSI, and BMPyTFSI) in hydroxy-functionalized multi-walled carbon nanotubes (MWCNT-OH) reinforced hydrogenated poly(acrylonitrile-co-1,3-butadiene) (HNBR) produce homogeneous solids. HNBR/MWCNT-OH/ionic liquid solid electrolytes were prepared by melt compounding of the nanotubes in the elastomer, mixing with curing system, curing, and immersion in the ionic liquid. Cross-linked with 12.9 wt% of the curing system (per total composite weight prior to ionic liquid sorption), these HNBR-based electrolytes displayed elastomeric properties and high tensile strength (up to 24 MPa). HNBR/MWCNT-OH/ionic liquid composites had the elongation at break up to 378% (BMPyTFSI) at the room temperature and ionic liquid concentrations up to 18 wt% (BMImTFSI). Thermal analysis showed that the T g of HNBR/MWCNT-OH/ionic liquid systems decreased as a function of increasing ionic liquid content at the constant polymer content in a composite. © 2011 The Royal Society of Chemistry.

Cepic M.,University of Ljubljana
Physics Education | Year: 2012

Anisotropy is a difficult concept, although it is often met in everyday life. This paper describes a simple model-knitted patterns-having anisotropic elastic properties. The elastic constant is measured for the force applied in different directions with respect to the knitting direction. It is also shown that the deformation of the knitted pattern does not always have the same direction as the applied force, a behaviour that is also typical for anisotropic systems. The dependence of the elastic coefficient on the direction of applied force has the same form as the refraction coefficient of an extraordinary ray in a uniaxial anisotropic crystal. © 2012 IOP Publishing Ltd.

Rizner T.L.,University of Ljubljana
Frontiers in Pharmacology | Year: 2012

Endometrial and cervical cancers, uterine myoma, and endometriosis are very common uterine diseases. Worldwide, more than 800,000 women are affected annually by gynecological cancers, as a result of which, more than 360,000 die. During their reproductive age, about 70% of women develop uterine myomas and 10-15% suffer from endometriosis. Uterine diseases are associated with aberrant inflammatory responses and concomitant increased production of prostaglandins (PG). They are also related to decreased differentiation, due to low levels of protective progesterone and retinoic acid, and to enhanced proliferation, due to high local concentrations of estrogens. The pathogenesis of these diseases can thus be attributed to disturbed PG, estrogen, and retinoid metabolism and actions. Five human members of the aldo-keto reductase 1B (AKR1B) and 1C (AKR1C) superfamilies, i.e., AKR1B1, AKR1B10, AKR1C1, AKR1C2, and AKR1C3, have roles in these processes and can thus be implicated in uterine diseases. AKR1B1 and AKR1C3 catalyze the formation of PGF2α, which stimulates cell proliferation. AKR1C3 converts PGD2 to 9α,11β-PGF2, and thus counteracts the formation of 15-deoxy-PGJ2, which can activate pro-apoptotic peroxisome-proliferator-activated receptor γ. AKR1B10 catalyzes the reduction of retinal to retinol, and thus lessens the formation of retinoic acid, with potential pro-differentiating actions. The AKR1C1-AKR1C3 enzymes also act as 17-ketoand 20ketosteroid reductases to varying extents, and are implicated in increased estradiol and decreased progesterone levels. This review comprises an introduction to uterine diseases and AKR1B and AKR1C enzymes, followed by an overview of the current literature on the AKR1B and AKR1C expression in the uterus and in uterine diseases. The potential implications of the AKR1B and AKR1C enzymes in the pathophysiologies are then discussed, followed by conclusions and future perspectives. © 2012 Rižner.

Rupnik H.,University of Ljubljana | Rupnik H.,Dermatology Center Arsderma | Rijavec M.,University Clinic of Respiratory and Allergic Diseases | Korosec P.,University Clinic of Respiratory and Allergic Diseases
British Journal of Dermatology | Year: 2015

Background The influence of filaggrin gene (FLG) mutations on early- vs. late-onset development of atopic dermatitis (AD), allergic contact dermatitis (ACD) and chronic irritant contact dermatitis (CICD) is not completely understood. Objectives To assess the association between FLG mutations and development of AD, ACD and CICD. Methods This study assessed 241 patients with AD. AD developed during infancy in 85 patients, during childhood in 79 patients (32 early and 47 late) and during adulthood in 77 patients. We also included 100 patients with ACD and 44 with CICD, as well as 164 healthy controls. Four prevalent FLG loss-of-function mutations were genotyped (R501X, 2282del4, R2447X and S3247X). Results The 2282del4 mutation was significantly associated with a greater risk of AD in the entire group [odds ratio (OR) 4·33, 95% confidence interval (CI) 1·26-14·96]. However, the 2282del4 mutation was associated only with AD that developed during infancy or in early childhood (≤ 8 years: OR 20·91, 95% CI 2·73-159·9), not with AD development in late childhood or adulthood (> 8 or > 18 years), or ACD or CICD. Similar associations were also observed for the combined 2282del4 or R501X genotype. Carriers of FLG mutations also experienced a longer duration of AD and required hospitalization more often. Conclusions FLG mutations are associated with only the early onset of AD, not late onset. Other factors should receive attention in patients with late-onset AD. © 2014 British Association of Dermatologists.

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.

Purpose: The paper aims to assess the utility of non-agriculture-specific information systems, databases, and respective controlled vocabularies (thesauri) in organising and retrieving agricultural information. The purpose is to identify thesaurus-linked tree structures, controlled subject headings/terms (heading words, descriptors), and principal database-dependent characteristics and assess how controlled terms improve retrieval results (recall) in relation to free-text/uncontrolled terms in abstracts and document titles. Design/methodology/approach: Several different hosts (interfaces, platforms, portals) and databases were used: CSA Illumina (ERIC, LISA), Ebscohost (Academic Search Complete, Medline, Political Science Complete), Ei-Engineering Village (Compendex, Inspec), OVID (PsycINFO), ProQuest (ABI/Inform Global). The search-terms agriculture and agricultural and truncated word-stem agricultur- were employed. Permuted (rotated index) search fields were used to retrieve terms from thesauri. Subject-heading search was assessed in relation to free-text search, based on abstracts and document titles. Findings: All thesauri contain agriculture-based headings; however, associative, hierarchical and synonymous relationships show important inter-database differences. Using subject headings along with abstracts and titles in search syntax (query) sometimes improves retrieval by up to 60 per cent. Retrieval depends on search fields and database-specifics, such as autostemming (lemmatization), explode function, word-indexing, or phrase-indexing. Research limitations/implications: Inter-database and host comparison, on consistent principles, can be limited because of some particular host- and database-specifics. Practical implications: End-users may exploit databases more competently and thus achieve better retrieval results in searching for agriculture-related information. Originality/value: The function of as many as ten databases in different disciplines in providing information relevant to subject matter that is not a topical focus of databases is assessed. © Emerald Group Publishing Limited.

Bester-Rogac M.,University of Ljubljana | Stoppa A.,University of Regensburg | Buchner R.,University of Regensburg
Journal of Physical Chemistry B | Year: 2014

Molar conductivities, Λ, of dilute solutions of the ionic liquids (ILs) 1-ethyl-3-methylimidazolium tetrafluoroborate ([emim][BF4]), 1-butyl-3-methylimidazolium tetrafluoroborate ([bmim][BF4]), 1-butyl-3-methylimidazolium hexafluorophosphate ([bmim][PF6]), 1-hexyl-3-methylimidazolium tetrafluoroborate ([hmim][BF4]), and 1-hexyl-3-methylimidazolium bis(trifluoromethanesulfonyl)amide ([hmim][NTf 2]) in acetonitrile (AN) were determined as a function of temperature in the range 273.15-313.15 K. The data were analyzed with Barthel's lcCM model to obtain limiting molar conductivities, Λ∞(T), and association constants, KA (T) of these electrolytes. The temperature dependence of these parameters, as well as the extracted limiting cation conductivities, λi∞, were discussed. Additionally, dielectric spectra for [hmim][NTf2] + AN were analyzed in terms of ion association and ion solvation and compared with the inference from conductivity. It appears that in dilute solutions the imidazolium ring of the cations is solvated by ∼6 AN molecules that are slowed by a factor of ∼8-10 compared to the bulk-solvent dynamics. Ion association of imidazolium ILs to contact ion pairs is only moderate, similar to common 1:1 electrolytes in this solvent. © 2014 American Chemical Society.

Poljsak B.,University of Ljubljana
Oxidative Medicine and Cellular Longevity | Year: 2011

The reduction of oxidative stress could be achieved in three levels: by lowering exposure to environmental pollutants with oxidizing properties, by increasing levels of endogenous and exogenous antioxidants, or by lowering the generation of oxidative stress by stabilizing mitochondrial energy production and efficiency. Endogenous oxidative stress could be influenced in two ways: by prevention of ROS formation or by quenching of ROS with antioxidants. However, the results of epidemiological studies where people were treated with synthetic antioxidants are inconclusive and contradictory. Recent evidence suggests that antioxidant supplements (although highly recommended by the pharmaceutical industry and taken by many individuals) do not offer sufficient protection against oxidative stress, oxidative damage or increase the lifespan. The key to the future success of decreasing oxidative-stress-induced damage should thus be the suppression of oxidative damage without disrupting the wellintegrated antioxidant defense network. Approach to neutralize free radicals with antioxidants should be changed into prevention of free radical formation. Thus, this paper addresses oxidative stress and strategies to reduce it with the focus on nutritional and psychosocial interventions of oxidative stress prevention, that is, methods to stabilize mitochondria structure and energy efficiency, or approaches which would increase endogenous antioxidative protection and repair systems. Copyright © 2011 B. Poljsak.

Poijak M.,University of Ljubljana
Acta Dermatovenerologica Alpina, Pannonica et Adriatica | Year: 2011

Background: Human papillomaviruses (HPV), remarkably diverse DNA viruses etiologically linked with various benign and malignant neoplastic lesions of mucosal and skin epithelium, have been the subject of intensive research for the last 30 years worldwide. Objective: Briefly to review 20 years of HPV research in Slovenia by analyzing the articles published in journals indexed in peer-reviewed databases Medline/Pubmed, Science Citation Index/Web of Science, Embase and PsycINFO. Methods and Results: Up until October 2011, Slovenian researchers published 73 articles in journals indexed in peer-reviewed databases, which can be divided into 15 categories: detection of HPV in archival clinical specimens, development of novel HPV tests, evaluation of various commercial tests for the detection of high- and low-risk alpha-HPV, HPV and anogenital tumours, HPV testing in routine gynecological practice, HPV and laryngeal benign tumours, HPV and laryngeal epithelial hyperplastic lesions and laryngeal cancer, HPV and tumors in oral cavity, HPV and esophageal benign and malignant tumors, HPV and inverted papillomas, genomic diversity of selected HPV types, hair follicles as an important endogenous reservoir of HPV, identification and characterization of novel HPV types, HPV vaccination and HPV basic research. Until October 2011, Slovenian HPV papers received 473 citations (self-citation excluded) and their Hirsch index is currently h=13. Conclusion: In the last 20 years, Slovenian HPV researchers have been actively and successfully incorporated in the international HPV community and have contributed small but significant achievements in the field.

Benatti F.,University of Trieste | Benatti F.,National Institute of Nuclear Physics, Italy | Floreanini R.,National Institute of Nuclear Physics, Italy | Marzolino U.,University of Ljubljana
Physical Review A - Atomic, Molecular, and Optical Physics | Year: 2014

Entanglement in fermion many-body systems is studied using a generalized definition of separability based on partitions of the set of observables, rather than on particle tensor products. In this way, the characterizing properties of nonseparable fermion states can be explicitly analyzed, allowing a precise description of the geometric structure of the corresponding state space. These results have direct applications in fermion quantum metrology: Sub-shot-noise accuracy in parameter estimation can be obtained without the need of a preliminary state entangling operation. © 2014 American Physical Society.

The affinity of amphiphilic compounds for water is important in various processes, e.g., in conformational transitions of biopolymers, protein folding/unfolding, partitioning of drugs in the living systems, and many others. Herein, we study the conformational transition of two isomer forms of poly(methacrylic acid) (PMA), isotactic (iPMA) and atactic (aPMA), in water. These isomers are chemically equivalent and differ only in the arrangement of functional groups along the chain. A complete thermodynamic analysis of the transition of the PMA chains from the compact to the extended form (comprising the conformational transition) in water in the presence of three alkali chlorides is conducted by determining the free energy, enthalpy, and entropy changes of the process as a function of temperature, and therefrom also the heat capacity change. The heat capacity change of the transition is positive (+20 J/K mol) for aPMA and negative (-50 J/K mol) for iPMA. This result suggests a different affinity of PMA isomers for water. The conformational transition of iPMA is parallel to the transfer of polar solutes into water, whereas that of aPMA agrees with the transfer of nonpolar solutes into water. © 2016 by the authors.

Trcek D.,University of Ljubljana
IEEE Security and Privacy | Year: 2011

The study of trust should be multidisciplinary. This primarily means including computing and information science on one hand, and psychology on the other. Although some research projects have already employed multidisciplinary approaches, they've rarely included all the necessary ingredients. Furthermore, the core of the trust phenomenon is often overlooked. In addition, to complement current quantitative methodologies, we should develop methodologies that support a quantitative treatment by using qualitative assessments of trust. © 2006 IEEE.

Parpura V.,University of Alabama at Birmingham | Zorec R.,University of Ljubljana | Zorec R.,Technology Park Ljubljana
Brain Research Reviews | Year: 2010

Gliotransmitters are chemicals released from glial cells fulfilling a following set of criteria: (i) they are synthesized by and/or stored in glia; (ii) their regulated release is triggered by physiological and/or pathological stimuli; (iii) they activate rapid (milliseconds to seconds) responses in neighboring cells; and (iv) they play a role in (patho)physiological processes. Astrocytes can release a variety of gliotransmitters into the extracellular space using several different mechanisms. In this review, we focus on exocytotic mechanism(s) underlying the release of three classes of gliotransmitters: (i) amino acids, such as, glutamate and d-serine; (ii) nucleotides, like adenosine 5'-triphosphate; and (iii) peptides, such as, atrial natriuretic peptide and brain-derived neurotrophic factor. It is becoming clear that astrocytes are endowed with elements that qualify them as cells communicating with neurons and other cells within the central nervous system by employing regulated exocytosis. © 2009 Elsevier B.V.

There have been intensive efforts to try to understand the details of phosphoryl transfer reactions extending from nonenzymatic (or enzyme model) systems to the mechanisms of the enzyme catalysed reactions. As phosphate analogues, few metallic fluorides AlFx, BeFx and MgF x affect the activity of a variety of phosphoryl transfer enzymes, and it is accepted that these small inorganic complexes are useful chemical probes for structural and mechanistic studies in enzymology because they are able to mimic phosphoryl group in ground state (BeFx) as well as in transition state (AlFx,Mg- Fx). Al3+ and Be2+ tend to form stable complexes with different fluoride anions (x = 1 to 4) spontaneously in aqueous solution but Mg2+ does not. BeFx geometry is strictly tetrahedral resembling the phosphate ground state when bound to an acyl group of protein active site (phosphorylated acyl groups are unstable otherwise), or the Michaelis complex when BeFx concominantly with nucleoside diphosphate replaces γ-phosphate group in nucleoside triphosphate sites. AlFx and MgFx are identified as enzymatic analogues of phosphoryl transition state where both are able to form different coordination geometries within the enzyme active sites: trigonal bipyramidal (AlF3 and MgF3-) or octahedral (AlF4 - or Mg- F42-). The geometry and charge of MgF3- are the best suited to mimicking the trigonal planar PO3- moiety of phosphoryl transfer transition state but MgF3- does not, unlike aluminum and beryllium fluoride complexes, exists in solution and can be assembled and stabilized in suitable active site only. Therefore it is particularly interesting to characterize as a potentially highly accurate transition state analogue and may be the best reagent of choice for studying phosphoryl transfer reactions in future.

Kostic U.,University of Ljubljana
General Relativity and Gravitation | Year: 2012

Time-like orbits in Schwarzschild space-time are presented and classified in a very transparent and straightforward way into four types. The analytical solutions to orbit, time, and proper time equations are given for all orbit types in the form r = r(λ), t = t(χ), and τ= τ (χ), where λ is the true anomaly and χ is a parameter along the orbit. A very simple relation between λ and χ is also shown. These solutions are very useful for modelling temporal evolution of transient phenomena near black holes since they are expressed with Jacobi elliptic functions and elliptic integrals, which can be calculated very efficiently and accurately. © 2012 Springer Science+Business Media, LLC.

Jerina K.,University of Ljubljana
Journal of Mammalogy | Year: 2012

Most studies on the relationship between home-range size and composition focus on natural factors, whereas effects of anthropogenic factors are poorly understood. I evaluated effects of multiple natural and anthropogenic habitat factors, population density, and sex on the annual home-range size of red deer (Cervus elaphus) in well-preserved forest areas in the Dinaric Mountains of Slovenia, Europe, based on >11,000 telemetry locations from 17 males and 25 females. Home ranges were 902,107 ha and averaged 460 ha. Using a mixed linear model, I estimated that home-range size decreased with increasing 1) red deer density, 2) supplemental feeding intensity, and 3) average annual temperature; 4) home-range size increased as the distance of main roads from the edge of the home range increased; and 5) males had a larger home range than females (580 ha versus 400 ha). These results were explained by effects of food availability (1, 2, and 3), energy expenditure of an individual (4 and 5), intraspecific interactions (1 and 5), and size of unfragmented habitat patches (4) on home-range size. To my knowledge, this is the 1st large mammal study to explicitly show that the density and spatial distribution of roads and supplemental feeding affect home-range size of red deer and that humans can have a greater impact on home-range size and shape than natural habitat factors. Ungulates are often supplementally fed to increase their value to hunters and to reduce forest damage, particularly in Europe; however, this practice can greatly reduce the home-range size, potentially leading to increased disease transmission and competition associated with the higher deer densities around feeding sites, which can result in just the opposite of what was intended. © 2012 American Society of Mammalogists.

Mahnic V.,University of Ljubljana
International Journal of Engineering Education | Year: 2010

In order to prepare students for the increasing use of agile methods in industry, teaching these methods is becoming an important part of the Computer Science and Software Engineering curricula. So far most of the attention has been devoted to Extreme Programming and its practices, but there is not much reported about teaching Scrum, in spile of the fact that Scrum is one of the most widespread agile methods. To fill this gap, a course was developed at the University of Ljubljana that not only teaches Scrum through a capstone project, but also serves as a study about the learnability and applicability of Scrum. This paper describes the course details and analyses students' perceptions and teachers' observations after running the course for the first time in the Spring semester of the Academic Year 2008109. The student surveys showed that students were overwhelmingly positive about the course and confirmed the anecdotal evidence of Scrum's benefits as reported in the literature. © 2010 TEMPUS Publications.

Vidic A.D.,University of Ljubljana
International Journal of Engineering Education | Year: 2010

Assessment in problem-based learning (PBL) incorporated into traditional engineering education should lead students to fulfil the PBL aims. Using process and outcome-oriented assessment methods, we introduced an assessment scheme that addresses all eleven outcomes of EAC 3 in engineering and contains individual and group assessment. The present article aims to expose and present difficulties of group assessment with 'problem projects' integrated in the assessment scheme. 'Problem projects' could provide an objective picture of individual student's knowledge, skills and progress if they are used in combination with other assessment elements from the scheme. The assessment scheme was used in an experiment, where PBL and traditional instruction were compared in an introductory statistics course. In the experiment, significant difference in students' achievements across 'problem projects' was observed. Despite difficulties in assessment the results encouraged us to use PBL also in other subjects. © 2010 TEMPUS Publications.

The glucagon-like peptide-1 receptor (GLP-1 receptor) mediates important antidiabetogenic effects on peripheral tissues. It appears to be one of the most promising therapeutic targets for treatment of diabetes mellitus type 2. Surprisingly, very little is known about the cellular mechanisms that regulate receptor function in living cells. One of the approaches how to study receptor dynamics is by using tagged fluorescent proteins. In this study, YFP-tagged GLP-1 (YFP-GLP-1) receptor and CFP-tagged GLP-1 (CFP-GLP-1) receptor for visualizing protein-protein interaction in living cells were constructed and localized in CHO cells. Cells expressing YFP-GLP-1 and CFP-GLP-1 receptor showed characteristic GLP-1 mediated increase in cAMP, similar to cells expressing a wild type GLP-1 receptor. This means that both types of receptors are functional and localized in plasma membrane. © 2009 Springer Science+Business Media B.V.

Konvalinka Matjaz.,University of Ljubljana
Journal of Combinatorial Theory. Series A | Year: 2015

Recently, residue and quotient tables were defined by Fishel and the author, and were used to describe strong covers in the lattice of k-bounded partitions. In this paper, we prove (and, in some cases, conjecture) that residue and quotient tables can be used to describe many other results in the theory of k-bounded partitions and k-Schur functions, including k-conjugates, weak horizontal and vertical strips, and the Murnaghan-Nakayama rule. Evidence is presented for the claim that one of the most important open questions in the theory of k-Schur functions, a general rule that would describe their product, can be also concisely stated in terms of residue tables. © 2015 Elsevier Inc..

Ilic M.,University of Ljubljana
European journal of medicinal chemistry | Year: 2012

Fluorinated 3,4-dihydro-2H-1,4-benzoxazine derivatives possessing both thrombin inhibitory and glycoprotein IIb/IIIa receptor antagonistic activities were prepared as potential dual antithrombotic compounds. Fluorine scan (3-fluorobenzyl, 4-fluorobenzyl, 3,4-difluorobenzyl and 3,5-difluorobenzyl substituted compounds) was performed in order to obtain 6-(carboxymethyl)(3,4-difluorobenzyl)amino compound (9i) as the most potent compound with balanced dual activity (K(i(Thr))=0.33±0.07μM, IC(50(GP IIb/IIIa))=1.1±0.6μM). Copyright © 2012 Elsevier Masson SAS. All rights reserved.

Gomboc A.,University of Ljubljana
Contemporary Physics | Year: 2012

Gamma Ray Bursts are unpredictable and brief flashes of gamma rays that occur about once a day in random locations in the sky. Since gamma rays do not penetrate the Earth's atmosphere, they are detected by satellites, which automatically trigger ground-based telescopes for follow-up observations at longer wavelengths. In this introduction to Gamma Ray Bursts we review how building a multi-wavelength picture of these events has revealed that they are the most energetic explosions since the Big Bang and are connected with stellar deaths in other galaxies. However, in spite of exceptional observational and theoretical progress in the last 15 years, recent observations raise many questions which challenge our understanding of these elusive phenomena. Gamma Ray Bursts therefore remain one of the hottest topics in modern astrophysics. © 2012 Copyright Taylor and Francis Group, LLC.

Bauer A.,University of Ljubljana
Theoretical Computer Science | Year: 2012

We show that in the effective topos there is a chain-complete distributive lattice with a monotone and progressive endomap which does not have a fixed point. An immediate consequence of this is that both Tarski's theorem for chain-complete posets and the Bourbaki-Witt theorem have no constructive (topos-valid) proofs. © 2012 Elsevier B.V. All rights reserved.

Bavec A.,University of Ljubljana
Life Sciences | Year: 2014

Insulin therapy remains the standard of care for achieving and maintaining adequate glycemic control, especially in hospitalized patients with critical and noncritical illnesses. Insulin therapy is more effective against elevated fasting glycaemia but less in the reduction of postprandial hyperglycaemia. It is associated with a high incidence of hypoglycemia and weight gain. Contrary, GLP-1 mimetic therapy improves postprandial glycaemia without the hypoglycaemia and weight gain associated with aggressive insulin therapy. Moreover, it has the potential to reduce cardiovascular related morbidity. However, its increased immunogenicity and severe gastrointestinal adverse effects present a huge burden on patients. Thus, a right combination of basal insulin which has lowering effect on fasting plasma glucose and GLP-1 mimetic with its lowering effect on postprandial plasma glucose with minimal gastrointestinal adverse effects, seems the right therapy choice from a clinical point of view for some diabetic patients. In this article, we discuss the pros and cons of the use of insulin analogues and GLP-1 mimetics that are associated with the treatment of type 2 diabetes. © 2014 Elsevier Inc.

Kreft L.,University of Ljubljana
International Journal of Sport Policy | Year: 2011

Athletes Whereabouts Information demands that 'athletes who have been identified by their International Federation or National Anti-Doping Organization for inclusion in a Registered Testing Pool shall provide accurate, current location information'. As from 1 January 2009, this means that elite level athletes have to report on their out-ofcompetition whereabouts 24 h per day and 7 days a week. This kind of total surveillance requires active participation of athletes, starting with their signature allowing anti-doping authorities to reach them anytime and anywhere. This instrument of control has been discussed from moral and legal points of view, especially as potential human rights violation, and with conclusions which either support or criticize the instrument. This article seeks to contribute to another topic: Why did anti-doping control in elite sport develop in such a way that it demands measures which would be unacceptable if introduced by any other state or international authority? There are two main reasons: moralization and the special kind of precariousness of sport work. Moralization can be detected in many areas of social life, as morality's subordination to claims for control and eradication of evil, and its result is subordination of legality to morality: that is what happened in sport, starting from 'war on doping' and 'zero-tolerance' politics which are both typical signs of moralization. Precariousness is a situation in which increasing numbers of workers are engaged in insecure, casualized or irregular labour. Sport professionals found themselves in precarious situation much earlier than all the other professionals because of the nature and limits of their profession. What is special in their working conditions is, however, that they at the same time represent labour force and product, and this product is their own body together with their body's abilities. Antidoping control starts from their precarious position: they do not have a choice but to accept its demands because their job depends on it. However, they are not only tested as labour force, but also as commodities, as in the quality of food and other goods that have to be clear and healthy. For commodities, of course, human rights do not apply. © 2011 Taylor & Francis.

Using specific scientific methods and through a model, the paper determines how investments in the railway infrastructure influence the whole railway system. The research is based on experience and on the results that have been found out in Austria, Argentina, Bolivia, Brazil, Chile and Venezuela. Based on scientific studies about the conditions of the Slovenian railway system, on the Methodology for determination of the investment measures and definition of conditions for a justified realisation and on the Calculation of the expected number of freight trains, the results that confirm the hypothesis of mid and long-term positive effects of investments in the railway network are given © 2014, Faculty of Transport and Traffic Engineering. All rights reserved.

Demsar J.,University of Ljubljana
Artificial life | Year: 2014

It is not exactly known why birds aggregate in coordinated flocks. The most common hypothesis proposes that the reason is protection from predators. Most of the currently developed examples of individual-based predator-prey models assume predators are attracted to the center of a highly coordinated flock. This proposed attraction of a predator to a flock would appear to be contradictory to an alternate hypothesis that flocks evolved as a protection against predation. In an attempt to resolve this apparent conflict, in this article we use a fuzzy individual-based model to study three attack tactics (attack center, attack nearest, attack isolated) and analyze the success of predation on two types of prey (social and individualistic). Our simulations revealed that social flocking (as opposed to individualistic behavior) is the optimal anti-predatory response to predators attacking mainly isolated individuals.

Peternel S.,Slovenian National Institute of Chemistry | Peternel S.,University of Ljubljana
New Biotechnology | Year: 2013

Recombinant protein production significantly improved in the past three decades. Novel expression systems were developed, growth conditions optimised and the technology and thus monitoring and analysis significantly enhanced. However, the studies of bacterial cell disruption were more or less neglected. The existing methods were acceptable until the final product of protein production was soluble and pure protein. However recently, inclusion bodies (IBs) as whole protein particles were also recognised as the final product. Classical methods for bacterial cell disruption are therefore not always suitable, sufficient or even appropriate for isolation of such particulate material. Some of the currently existing methods for bacterial cell disruption were recognised as damaging for the structure of IBs, while sonication was even found harmful for the recombinant protein. The powers needed for disruption of the bacterial cells damage the recombinant proteins and thus their biological activity significantly reduces. Furthermore, the classical isolation methods enable disruption of majority of the bacterial cells and this is enough for isolation of soluble proteins, yet it is not adequate for isolation of particulate material. While remaining bacterial cells sediment together with the IBs, they represent impurity. The need for isolation of cell-free IBs was therefore revealed in the recent studies, because only pure IBs can be used as nanoparticles in further biomedical applications. Therefore it is time to consider, redesign, optimise or even develop new alternative methods that would enable isolation of pure, structurally intact and biologically active particles. Two such alternative methods that enable isolation of bacterial free, active protein particles were developed recently. © 2011 Elsevier B.V.

Mean-value engine models (MVEMs) are frequently applied in system-level simulations of vehicle powertrains. In particular, MVEMs are a common choice in engine simulators, where real-time execution is mandatory. In the case of real-time applications with prescribed, fixed sampling times, the use of explicit integration schemes is almost mandatory. Thus the stability of MVEMs is one of the main limitations when it comes to optimizing their performance. It is limited either by the minimum size of the gas volume elements or by the maximum integration time step. An innovative approach that addresses both constraints arises from the fact that the mass flow through the transfer elements of the MVEM is not modelled considering the quasi-steady assumption, but instead the mass-flow is calculated using a single transient momentum balance (TMB) equation. The proposed approach closely resembles phenomena in the physical model, since it considers both the flow-field history and the inertial effects arising from the time variation of the mass flow. It is shown in this paper that a consideration of the TMB equation improves the stability and/or the computational speed of the MVEMs, whereas it also makes it possible to capture physical phenomena in a more physically plausible manner. © 2013 by the authors.

Jevtic V.,University of Ljubljana
Handchirurgie Mikrochirurgie Plastische Chirurgie | Year: 2012

The 2 major and clinically most important primary inflammatory rheumatic diseases which affect small hand and feet joints are rheumatoid arthritis (RA) and psoriatic arthritis (PsA). The most important initial histopathological feature of RA is synovitis followed by chronic proliferative granulomatous pannus-tissue, which is associated with cartilage and bone destruction. Early inflammatory changes in RA also develop synchronously within the subchondral bone marrow. Enthesitis is the hallmark of SNSA, and is often seen as one of the first radiological manifestations of the diseases. As a rule inflammation within the synovial joints, histologically similar to RA, is not so pronounced. Consequently destructive changes within the synovial joints are much less with the exception of PsA in which pronounced bone destruction may develop (arthritis mutilans). Considerable overlapping in clinical and morphological manifestation of RA and PsA may be present. For evaluation of hand and feet joints and surrounding soft tissue structures in RA and PsA different imaging modalities are used, which include projection radiography, ultrasonography (US), radionuclide techniques and magnetic resonance imaging (MRI). MRI has become the imaging modality of choice for evaluation of arthritis, when conventional radiography is not conclusive. © Georg Thieme Verlag KG Stuttgart · New York.

Saksida P.,University of Ljubljana
Journal of Physics: Conference Series | Year: 2012

In this paper we construct a new Lax pair for the Klein-Gordon equation. The structure algebra of this Lax pair is the algebra T A 2 of upper triangular Toeplitz block matrices with blocks. For the suitable choice of the values of the spectral parameter, the integrals of motion, obtained from the holonomy of the spatial part of the Lax pair, have simple expressions in terms of the Fourier data. We compare these integrals to the corresponding integrals of the sine-Gordon system.

Bratkovic T.,University of Ljubljana | Rogelj B.,Institute of Psychiatry
Cellular and Molecular Life Sciences | Year: 2011

Small nucleolar RNAs (snoRNAs) constitute a group of non-coding RNAs principally involved in posttranscriptional modification of ubiquitously expressed ribosomal and small nuclear RNAs. However, a number of tissue-specific snoRNAs have recently been identified that apparently do not target conventional substrates and are presumed to guide processing of primary transcripts of protein-coding genes, potentially expanding the diapason of regulatory RNAs that control translation of mRNA to proteins. Here, we review biogenesis of snoRNAs and redefine their function in light of recent exciting discoveries. We also discuss the potential of recombinant snoRNAs to be used in modulation of gene expression. © Springer Basel AG 2011.

Nastran M.,University of Ljubljana
Journal of Environmental Planning and Management | Year: 2014

Stakeholder analysis is the key step towards a successful participatory spatial planning. The case study of the protected area in designation features stakeholder analysis as a tool in defining the salience of the stakeholders' involvement in the designation and the operations of the Kamniško-Savinjske Alps Regional Park in Slovenia. The salience of a stakeholder was determined using a flexible method using numerical evaluations of three stakeholder attributes: power, legitimacy and interest. Local farmers and residents are the key stakeholders in the research area. The survey explored which stakeholders they believe are necessary in individual phases of the protected area and how they would participate. The salience of different stakeholder groups varies during various project stages. Consequently, the perception of how and to what extent those stakeholders should participate also varies. © 2013 © 2013 University of Newcastle upon Tyne.

Cole M.W.,Rutgers University | Cole M.W.,Washington University in St. Louis | Repovs G.,University of Ljubljana | Anticevic A.,Yale University
Neuroscientist | Year: 2014

Recent findings suggest the existence of a frontoparietal control system consisting of flexible hubs that regulate distributed systems (e.g., visual, limbic, motor) according to current task goals. A growing number of studies are reporting alterations of this control system across a striking range of mental diseases. We suggest this may reflect a critical role for the control system in promoting and maintaining mental health. Specifically, we propose that this system implements feedback control to regulate symptoms as they arise (e.g., excessive anxiety reduced via regulation of amygdala), such that an intact control system is protective against a variety of mental illnesses. Consistent with this possibility, recent results indicate that several major mental illnesses involve altered brain-wide connectivity of the control system, likely altering its ability to regulate symptoms. These results suggest that this "immune system of the mind" may be an especially important target for future basic and clinical research. © The Author(s) 2014.

Background and Purpose: It is widely accepted that south-European peninsulas were major refugial areas from where European beech, Fagus sylvatica L., spread to the rest of Europe in the Holocene. The aim of this paper is to review and evaluate all the available data and present different types of evidence, some of them new or overlooked until now, to support the hypothesis on the existence of glacial refugia of European beech furt