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Kruzliak P.,St Annes University Hospital Brno | Kruzliak P.,Slovak Academy of Sciences | Novak J.,St Annes University Hospital Brno | Novak J.,Masaryk University | Novak M.,St Annes University Hospital Brno
American Journal of Hypertension | Year: 2014

Hypertension is the most common adverse effect of the inhibitors of vascular endothelial growth factor (VEGF) pathway-based therapy (VEGF pathway inhibitors therapy, VPI therapy) in cancer patients. VPI includes monoclonal antibodies against VEGF, tyrosine kinase inhibitors, VEGF Traps, and so-called aptamers that may become clinically relevant in the future. All of these substances inhibit the VEGF pathway, which in turn causes a decrease in nitric oxide (NO) and an increase in blood pressure, with the consequent development of hypertension and its final events (e.g., myocardial infarction or stroke). To our knowledge, there is no current study on how to provide an optimal therapy for patients on VPI therapy with hypertension. This review summarizes the roles of VEGF and NO in vessel biology, provides an overview of VPI agents, and suggests a potential treatment procedure for patients with VPI-induced hypertension. © American Journal of Hypertension, Ltd 2013.

Hafner J.,University of Vienna | Krajci M.,Slovak Academy of Sciences
Accounts of Chemical Research | Year: 2014

Complex intermetallic compounds are a class of ordered alloys consisting of quasicrystals and other ordered compounds with large unit cells; many of them are approximant phases to quasicrystals. Quasicrystals are the limiting case where the unit cell becomes infinitely large; approximants are series of periodic structures converging to the quasicrystal. While the unique properties of quasicrystals have inspired many investigations of their surfaces, relatively little attention has been devoted to the surface properties of the approximants.In general, complex intermetallic compounds display rather irregular, often strongly corrugated surfaces, making the determination of their atomic structure a very complex and challenging task. During recent years, scanning tunneling microscopy (STM) has been used to study the surfaces of several complex intermetallic compounds. If atomic resolution can be achieved, STM permits visualization of the local atomistic surface structure. However, the interpretation of the STM images is often ambiguous and sometimes even impossible without a realistic model of the structure of the surface and the distribution of the electronic density above the surface.Here we demonstrate that ab initio density functional theory (DFT) can be used to determine the energetics and the geometric and electronic structures of the stable surfaces of complex intermetallic compounds. Calculations for surfaces with different chemical compositions can be performed in the grand canonical ensemble. Simulated cleavage experiments permit us to determine the formation of the cleavage planes requiring the lowest energy. The investigation of the adsorption of molecular species permits a comparison with temperature-programmed thermal desorption experiments. Calculated surface electronic densities of state can be compared with the results of photoelectron spectroscopy. Simulations of detailed STM images can be directly confronted with the experimental results.Detailed results are presented for two intermetallic compounds that have recently attracted much attention as active and highly selective catalysts for the semihydrogenation of alkynes to alkenes, but the identification of the catalytically active surfaces was found to be very difficult. The crystal structure of B20-type GaPd can be interpreted as the lowest order approximant of icosahedral Al-Pd-Mn quasicrystals. Among the low-index surfaces, the {100} surface shows 2-fold symmetry and the {210} surface pseudo-5-fold symmetry; for both the surface stoichiometry is identical to that of the bulk. Because the structure lacks inversion symmetry, the {111} surfaces have polar character and permit terminations of widely different chemical composition. Results for all three surfaces are presented and compared with the available experiments. The crystal structure of orthorhombic Al13Co4 is built by pentagonal clusters similar to those found in decagonal Al-Co and Al-Ni-Co quasicrystals. A simulated cleavage experiment shows that the constituent clusters remain intact upon cleavage, resulting in the formation of a highly corrugated (100) surface. The calculated STM images are found to be in very good agreement with experiment and permit in addition identification of possible surface modifications by the desorption of individual atoms. Pentagonal motifs on the {210} surface of GaPd and on the (100) surface of Al13Co4 consisting of simple- and transition-metal atoms have been identified as the catalytically active centers for the semihydrogenation of acetylene to ethylene. © 2014 American Chemical Society.

Berke S.K.,University of Chicago | Jablonski D.,University of Chicago | Krug A.Z.,University of Chicago | Roy K.,University of California at San Diego | And 2 more authors.
Global Ecology and Biogeography | Year: 2013

Aim Variations in body size are well established for many taxa of endotherms and ectotherms, but remain poorly documented for marine invertebrates. Here we explore how body size varies with latitude, temperature and productivity for a major marine invertebrate class, the Bivalvia. Location Continental shelves world-wide. Methods We used regression models to assess univariate relationships between size and latitude as well as multivariate relationships between size, latitude and environmental parameters (mean and seasonality in temperature and mean productivity). The dataset consisted of 4845 species in 59 families from shelf depths at all latitudes in the Pacific and Atlantic oceans. We also used Blomberg's K to assess whether size-latitude relationships show phylogenetic signal, and test whether functional groups based on feeding mode, substrate relationships, mobility and fixation can account for observed size-latitude trends. Results Size-latitude trends are taxonomically and geographically common in bivalves, but vary widely in sign and strength - no simple explanations based on environmental parameters, phylogeny or functional group hold across all families. Perhaps most importantly, we found that the observed trends vary considerably between hemispheres and among coastlines. Main conclusions Broadly generalizable macroecological patterns in inter-specific body size may not exist for marine invertebrates. Although size-latitude trends occur in many bivalve lineages, the underlying mechanisms evidently differ among regions and/or lineages. Fully understanding macroecological patterns requires truly global datasets as well as information about the evolutionary history of specific lineages and regions. © 2012 Blackwell Publishing Ltd.

Lihova J.,Slovak Academy of Sciences | Kudoh H.,Kyoto University | Marhold K.,Charles University
American Journal of Botany | Year: 2010

Premise of the study: Studies on genetic structure of plant populations help us understand the history of local flora and vegetation. In this study, we focus on the temperate-boreal herb Cardamine scutata from northeast Asia, an area with scarce phylogeographic studies. We explore patterns of genetic variation within this species, with an aim to infer its (post-) glacial history with reference to colonization routes and migrations via land bridges. Methods: We analyzed 46 populations sampled in Japan, Kamchatka, and Korea using AFLP and cpDNA sequence data. Key results: Two intraspecific genetic groups were resolved, distributed in the northeastern and southwestern part of the study area, most likely reflecting lineages isolated from each other during (at least) the last glaciation. A zone of secondary contacts was found in central/northern Honshu, and a few cases of long-distance dispersal were observed. We detected efficient gene flow across the marine straits, supporting the role of land bridges created by sea level decline during the last glacial period. The cpDNA data indicated extensive recent expansion and diversification within both lineages. We inferred recent colonization of Kamchatka from Hokkaido, associated with genetic impoverishment. Conclusions: The pattern of north-south genetic differentiation found in C. scutata is rather common among several other plant species studied in Japan, despite their distinct biological features. We assume that different processes and factors may have brought about this similarity. Overall, this study contributes to better understanding of the biogeography of northeast Asia. © 2010 Botanical Society of America.

Dvurecenskij A.,Slovak Academy of Sciences
International Journal of Theoretical Physics | Year: 2011

We study states, measures, and signed measures on pseudo effect algebras with some version of the Riesz Decomposition Property (RDP). We show that the set of all Jordan signed measures is always an Abelian Dedekind complete ℓ-group. Therefore, the state space of a pseudo effect algebra with RDP is either empty or a nonempty Choquet simplex or even a Bauer simplex. This will allow to represent states on pseudo effect algebras by standard integrals. © 2011 Springer Science+Business Media, LLC.

Kawamura M.,RIKEN | Ono K.,RIKEN | Stano P.,RIKEN | Stano P.,Slovak Academy of Sciences | And 2 more authors.
Physical Review Letters | Year: 2015

We report an electronic magnetization measurement of a quantum point contact (QPC) based on nuclear magnetic resonance (NMR) spectroscopy. We find that NMR signals can be detected by measuring the QPC conductance under in-plane magnetic fields. This makes it possible to measure, from Knight shifts of the NMR spectra, the electronic magnetization of a QPC containing only a few electron spins. The magnetization changes smoothly with the QPC potential barrier height and peaks at the conductance plateau of 0.5×2e2/h. The observed features are well captured by a model calculation assuming a smooth potential barrier, supporting a no bound state origin of the 0.7 structure. © 2015 American Physical Society. © 2015 American Physical Society.

Dvurecenskij A.,Slovak Academy of Sciences
International Journal of Theoretical Physics | Year: 2011

We show conditions when a state on a quantum structure E like an effect algebra, a pseudo effect algebra E satisfying some kind of the Riesz Decomposition Properties (RDP) or on an MV-algebra, a BL-algebra, a pseudo MV-algebra and a pseudo BL-algebra is an integral through a regular Borel probability measure defined on the Borel σ-algebra of a Choquet simplex K. In particular, if E satisfies the strongest type of (RDP), the representing Borel probability measure can be uniquely chosen to have its support in the set of the extreme points of K. The same is true for states on an MV-algebra and a BL-algebra and their noncommutative variants. © 2011 Springer Science+Business Media, LLC.

Garcia J.A.,Autonomous University of Madrid | Glasa M.,Slovak Academy of Sciences | Cambra M.,Instituto Valenciano Of Investigaciones Agrarias Ivia | Candresse T.,French National Institute for Agricultural Research
Molecular Plant Pathology | Year: 2014

Summary: Taxonomic relationships: Plum pox virus (PPV) is a member of the genus Potyvirus in the family Potyviridae. PPV diversity is structured into at least eight monophyletic strains. Geographical distribution: First discovered in Bulgaria, PPV is nowadays present in most of continental Europe (with an endemic status in many central and southern European countries) and has progressively spread to many countries on other continents. Genomic structure: Typical of potyviruses, the PPV genome is a positive-sense single-stranded RNA (ssRNA), with a protein linked to its 5' end and a 3'-terminal poly A tail. It is encapsidated by a single type of capsid protein (CP) in flexuous rod particles and is translated into a large polyprotein which is proteolytically processed in at least 10 final products: P1, HCPro, P3, 6K1, CI, 6K2, VPg, NIapro, NIb and CP. In addition, P3N-PIPO is predicted to be produced by a translational frameshift. Pathogenicity features: PPV causes sharka, the most damaging viral disease of stone fruit trees. It also infects wild and ornamental Prunus trees and has a large experimental host range in herbaceous species. PPV spreads over long distances by uncontrolled movement of plant material, and many species of aphid transmit the virus locally in a nonpersistent manner. Sources of resistance: A few natural sources of resistance to PPV have been found so far in Prunus species, which are being used in classical breeding programmes. Different genetic engineering approaches are being used to generate resistance to PPV, and a transgenic plum, 'HoneySweet', transformed with the viral CP gene, has demonstrated high resistance to PPV in field tests in several countries and has obtained regulatory approval in the USA. © 2013 BSPP AND JOHN WILEY & SONS LTD.

Langer P.,Slovak Academy of Sciences
Frontiers in Neuroendocrinology | Year: 2010

High prevalence of thyroid and metabolic disorders has been repeatedly observed in the population living in the area of eastern Slovakia highly polluted by a mixture of PCBs, DDE and HCB since about 50 years ago. Among thyroid disorders, increase of thyroid volume as measured by ultrasound volumetry may be suggested as one of notable findings which appeared possibly related to increased OCs levels and to autoimmunity signs (e.g. positive thyroperoxidase antibodies in blood and/or hypoechogenicity image obtained by ultrasound), while some participation of individual susceptibility and also of immunogenic effect of OCs and iodine in this iodine replete country cannot be excluded. Another notable finding has been the increase of blood FT4 and TT3 positively related to high PCBs level. Such increased FT4 level has been found associated with TSH level in hyperthyroid range in about 2% of examined population from polluted area. High prevalence of thyroid autoimmune disorders strongly supported the assumption on impaired immune system and thus also on presumably increased prevalence of other autoimmune disorders in highly exposed population. In addition, markedly increased prevalence of prediabetes and diabetes significantly related to major OCs (PCBs, DDE and HCB) levels and accompanied by increasing level of cholesterol and triglycerides has been observed. The observations also suggested a role of prenatal exposure to OCs in the development of several adverse health signs (e.g. increased prevalence of thyroid antibodies, impaired fasting glucose level, increased thyroid volume, decreased thymus volume, decreased neurobehavioral performance, increased hearing and dental disorders) in young generation born to highly exposed mothers in polluted area. © 2010 Elsevier Inc.

Samaj L.,Slovak Academy of Sciences | Jancovici B.,University Paris - Sud
Journal of Statistical Physics | Year: 2010

This paper is a continuation of the previous study (Šamaj in J. Stat. Phys. 137:1-17, 2009), where a sequence of sum rules for the equilibrium charge and current density correlation functions in an infinite (bulk) quantum media coupled to the radiation was derived by using Rytov's fluctuational electrodynamics. Here, we extend the previous results to inhomogeneous situations, in particular to the three-dimensional interface geometry of two joint semi-infinite media. The sum rules derived for the charge-charge density correlations represent a generalization of the previous ones, related to the interface dipole moment and to the long-ranged tail of the surface charge density correlation function along the interface of a conductor in contact with an inert (not fluctuating) dielectric wall, to two fluctuating semi-infinite media of any kind. The charge-current and current-current sum rules obtained here are, to our knowledge, new. The current-current sum rules indicate a breaking of the directional invariance of the diagonal current-current correlations by the interface. The sum rules are expressed explicitly in the classical high-temperature limit (the static case) and for the jellium model (the time-dependent case). © 2010 Springer Science+Business Media, LLC.

Kristek F.,Slovak Academy of Sciences
Current Pharmaceutical Biotechnology | Year: 2011

Long-term increase of blood pressure represents one of the most important risk factors triggering many cardiovascular diseases, and via counter-regulatory mechanisms it is itself modulated by them. Adequate perfusion of the respective areas with nutrients requires appropriate production of vasodilatory and vasoconstrictory agents. Disharmony among them has an important impact on mechanical properties of the arteries, resulting in pathological alterations in the cardiovascular system. Defective production of the vasodilatory agent nitric oxide (NO) has a pronounced effect on this delicate balance and can evoke functional and structural changes in the cardiovascular system leading to hypertension. This review is focused mainly on changes in the cardiovascular system of newborn and adult Wistar rats after long-term administration of two different types of NO-synthase inhibitors: nonspecific inhibitor N G-nitro-L-arginine methylester and specific inhibitor of neuronal NO-synthase 7-nitroindazole. A possible supplementation of decreased endogenous NO production by NO donors is discussed. Particular attention is given to the complex interplay among blood pressure, arterial geometry, including arterial wall thickness, cross-sectional area, inner diameter, and individual components of the arterial wall, as extracellular matrix, endothelial and smooth muscle cell trophicity. Some methodological remarks for determination of the arterial geometry are also presented. Better understanding of the interrelationship among the factors involved can help in explaining more accurately differences in functional manifestations of vessels in various types of hypertension. The review indicates that the current concept of NO production, effect of NO deficiency, substitution of the missing NO in failing NO production in the cardiovascular system appears to be oversimplified. © 2011 Bentham Science Publishers.

Olejnik S.,Slovak Academy of Sciences
Journal of Physics: Conference Series | Year: 2015

Beside anniversaries of the important discoveries celebrated at the DISCRETE 2014 Symposium, there is another worth to mention: The first paper attempting direct calculation of the Yang-Mills vacuum wave functional was published by Greensite in 1979. I review some recent results of the determination of the vacuum wave functional in Monte Carlo simulations of SU(2) lattice gauge theory.

Vranec P.,University of P.J. Safarik | Potocnak I.,University of P.J. Safarik | Kavecansky V.,Slovak Academy of Sciences
Polyhedron | Year: 2012

[Pt(CQ) 2] and [Pd(CQ) 2] (yellow and green) complexes (CQ = 5-chloro-7-iodo-quinolin-8-ol, clioquinol) were prepared as potential anticancer agents. X-ray structure analysis revealed that the yellow [Pd(CQ) 2] complex is a molecular coordination compound with Pd central atoms square-planarly coordinated by nitrogen and oxygen atoms of two trans-arranged bidentate molecules of CQ. Non-bonding interactions between parallel neighboring molecules in this complex were also investigated. The crystal structures of microcrystalline [Pt(CQ) 2] and green [Pd(CQ) 2] complexes were not solved but according to the LeBail (profile fitting) mode of the Rietveld analysis, all three complexes are isostructural. The complexes were characterized by thermal analysis, which revealed that they are stable up to 250 (yellow and green [Pd(CQ) 2]) and 230 °C ([Pt(CQ) 2]) as well as IR spectroscopy, which proved the presence of CQ in all complexes, and by elemental analysis which confirmed composition of the complexes. © 2012 Elsevier Ltd. All rights reserved.

Bella M.,Slovak Academy of Sciences | Bella M.,Slovak University of Technology in Bratislava | Milata V.,Slovak University of Technology in Bratislava
Tetrahedron | Year: 2014

A series of tricyclic azoloquinolones was prepared by a novel approach based on the protection of a benzene-1,2-diamine moiety as 2,1,3- benzoselenadiazole ring. A new reductive deselenation of 9-ethylselenadiazolo[3, 4-h]quinolones using zinc powder in acetic acid afforded 7,8-diamino-1- ethylquinolones in high yields. The obtained diaminoquinolones were employed as useful substrates in cyclocondensation reactions leading to azoloquinolone derivatives. © 2014 Elsevier Ltd. All rights reserved.

Gee D.G.,Uppsala University | Janak M.,Slovak Academy of Sciences | Majka J.,Uppsala University | Robinson P.,Geological Survey of Norway | van Roermund H.,University Utrecht
Lithosphere | Year: 2013

The recent discovery of ultrahigh-pressure (UHP) mineral parageneses in the far-transported (greater than 400 km) Seve Nappe Complex of the Swedish Caledonides sheds new light on the subduction system that dominated the contracting Baltoscandian margin of continental Baltica during the Ordovician and culminated in collision with Laurentia in the Silurian to Early Devonian. High-grade metamorphism of this Neoproterozoic to Cambrian rifted, extended, dike-intruded outer-margin assemblage started in the Early Ordovician and may have continued, perhaps episodically, until collision of the continents at the end of this period. The recent discovery of UHP kyanite eclogite in northern Jämtland (west-central Sweden) yields evidence of metamorphism at depths of 100 km. Although UHP rocks are only locally preserved from retrogression during the long-distance transport onto the Baltoscandian platform, these high-pressure parageneses indicate that deep subduction played an important role in the tectonothermal history of the complex. Based on existing isotopic age data, this UHP metamorphism occurred in the Late Ordovician, shortly before, or during, the initial collision between the continents (Scandian orogeny). In some central parts of the complex, migmatization and hot extrusion occurred in the Early Silurian, giving way to thrust emplacement across the Baltoscandian foreland basin and platform that continued into the Early Devonian. Identification of HP/UHP metamorphism at different levels within the Scandian allochthons, definition of their pressure-temperature-time paths, and recognition of their vast transport distances are essential for an understanding of the deeper structural levels of the orogen in the hinterland (e.g., the Western Gneiss Region), where the attenuated units were reworked together during the Early Devonian. © 2012 Geological Society of America.

Kuzmik J.,Slovak Academy of Sciences
Applied Physics Express | Year: 2012

Using a coupled Schrödinger-Poisson equation solver, we propose an N-polarity InN-channel quantum well high-electron-mobility transistors. The structure comprises from the bottom, a relaxed InAlN buffer with Al mole fraction between 0.1 and 0.3, GaN spacer with thickness less than 1 nm, 5 nm strained InN, and 5 nm ZrO 2 or HfO 2 to insulate a gate. Depending on the Al mole fraction, calculations indicate highly confined electrons in the channel with a two-dimensional density ranging from 1:6 × 10 13 to 3:5 × 10 13 cm -2. The polarity of the structure provides a possibility to grow InN as the last III-N layer with a relatively low polarization charge at the surface. © 2012 The Japan Society of Applied Physics.

Ceniga L.,Slovak Academy of Sciences
Meccanica | Year: 2012

This paper deals with analytical modelling of thermal stresses in a multi-particle-matrix system with isotropic spherical particles. These particles are periodically distributed in an isotropic infinite matrix. This model system which is characterized by microstructural parameters (particle volume fraction, particle radius) is applicable to two-phase composites of a precipitate-matrix type with isotropic phases. The thermal stresses originate during a cooling process due to a difference in thermal expansion coefficients. The analytical modelling which is based on fundamental equations of solid continuum mechanics represents a combination of different mathematical procedures applied to equilibrium and compatibility equations. This novel analytical model is compared with that which is based on mathematical procedures applied to the equilibrium equations only. The energy analysis of both analytical models which is applied to the SiC-Al 2O 3composite is presented. © Springer Science+Business Media B.V. 2011.

Capkovic F.,Slovak Academy of Sciences
Advances in Intelligent Systems and Computing | Year: 2014

Timed Petri nets (TPN) and first order hybrid Petri nets (FOHPN) are tested here in order to model transport systems and to find the suitable travel routes in different non-standard situations during the increased traffic density (i.e. at the bounded traffic or congestion). This work extends our previous work where the flexible routes in transport systems were found by means of the place/transition Petri nets (P/T PN). While at usage of the TPN only the time parameters are assigned to the P/T PN model transitions, the FOHPN model is different and it yields the continuous flows of vehicles. © Springer International Publishing Switzerland 2014

Mesiarova-Zemankova A.,Slovak Academy of Sciences
Fuzzy Sets and Systems | Year: 2016

The idempotent uninorms are characterized by means of the ordinal sum of Clifford. It is shown that idempotent uninorms are in one-to-one correspondence with special linear orders on [0,1]. A connection between respective linear order on [0,1] and the characterizing multi-function of the uninorm is also investigated. © 2016 Elsevier B.V.

Ugorcakova J.,Slovak Academy of Sciences
Bratislavské lekárske listy | Year: 2012

The determination of gene mutations is important for the diagnosis and prognosis of various gastrointestinal cancers. The aim of our study was to develop a new procedure for the analysis of KRAS gene mutation by application of the real-time PCR method. The detection process requires discriminate trace amount of mutant allele in a large excess of wild-type DNA in various samples. The real-time PCR based technique using hybridization probes for five most frequently KRAS codon 12 mutations and WT specific peptide nucleic acid (PNA) was performed. Our multiplex detection system was tested in various DNA samples (tissue, bile, pancreatic juice) of patients with different diagnoses of gastrointestinal tract disease obtained by endoscopy and ERCP. We designed and optimized the real-time PCR conditions and tested various amount of PNA in PCR reaction to suppress amplification of the wild-type DNA. We determined the interassay variability of the melting temperatures and the results of mutation testing were confirmed by DNA sequencing with the 100 % accuracy. Incidence of searched mutations was 67.5 % in cohort of 40 patients; for KRASG12D it was in 44.4 %, KRASG12V in 22.2 %, KRASG12S in 14.8 %, KRASG12A in 14.8 % and KRASG12C in 3.8 %. The sensitivity of the assays is 1x10-5. Advantages of this technique are rapidity, accuracy and it is generally easy to perform. This method can be adapted for synchronic detection of multiple mutations and after readjustment by other type mutation of KRAS gene may serve as useful clinical tool for analyzing point mutations in various clinical samples (Tab. 3, Fig. 3, Ref. 42).

Minarik G.,Comenius University | Tretinarova D.,Comenius University | Szemes T.,Comenius University | Kadasi L.,Slovak Academy of Sciences
International Journal of Pediatric Otorhinolaryngology | Year: 2012

Objectives: Non-syndromic hearing loss is one of the most common genetically determined diseases in human. The incidence is approximately 1:700 and most of the cases are caused by mutations in specific locus - DFNB1, which contains two genes - GJB2 and GJB6. For the GJB2 gene following mutations are most prevalent in specific populations - 35delG, 235delC, W24X and 167delT for Caucasians, Asians, Indians and Ashkenazi Jews, respectively. Large deletions are common in GJB6 gene. Many other mutations and polymorphisms were found in DFNB1 focused non-syndromic hearing loss studies thus the establishment of optimal screening protocol should be based on population specific mutation screening studies and is an objective in our study. Patients and methods: In our study samples from 273 non-syndromic hearing loss patients were screened for mutations in coding and non-coding part of GJB2 gene and large deletion in GJB6 gene - del(GJB6-D13S1830). Results: Causal mutation on both chromosomes was detected in 24.57% of patients, another 9.9% carried causal mutation on one chromosome. Totally 7 polymorphisms: V27I, M34T, F83L, 354 C → T, R127H, V153I, 684 C → A and 11 causal mutations: IVS1. +. 1 G → A, 35delG, W24X, V37I, E47X, 167delT, V84M, L90P, 310del14, 333-334delAA, R184Q were detected. No patient carried the GJB6 deletion mutation (del(GJB6-D13S1830)). Conclusion: According to our results sequencing of GJB2 coding regions and IVS1. +. 1G → A specific detection should explain approximately 25% of sporadic NSHL cases and these two tests are relevant for use as routine screening protocol for NSHL in Slovakia. The GJB6 del(GJB6-D13S1830) mutation was not detected in any of NSHL samples therefore it is not necessary to implement it in our routine screening protocol. © 2012 Elsevier Ireland Ltd.

Golysheva P.,Moscow State University | Shugarov S.,Slovak Academy of Sciences
Contributions of the Astronomical Observatory Skalnate Pleso | Year: 2014

Multicolor photometry of a new object PNV J19150199+0719471 during its superoutburst in June and July of 2013 is presented. The detailed light curves for different stages of a superoutburst were obtained and analyzed. The variations of the period and amplitude of superhumps were investigated. The tracks of the variable star on the two-colour diagrams were constructed and described.

Adamcik S.,Slovak Academy of Sciences | Buyck B.,CNRS Systematics, Biodiversity and Evolution Institute
Cryptogamie, Mycologie | Year: 2014

After a short historical summary of the species in Russula subgenus Compacta subsection Nigricantes in the United States, the microscopic features of the type specimens of four taxa from North America are described and discussed: Russula decora, R. densifolia var. paxilloides, R. sordida and R. subsordida. Previous suggestions of possible synonymies with European taxa are rejected. © 2014 Adac.

Janecek S.,Slovak Academy of Sciences | Svensson B.,Technical University of Denmark | MacGregor E.A.,2 Nicklaus Green
Enzyme and Microbial Technology | Year: 2011

Starch-binding domains (SBDs) comprise distinct protein modules that bind starch, glycogen or related carbohydrates and have been classified into different families of carbohydrate-binding modules (CBMs). The present review focuses on SBDs of CBM20 and CBM48 found in amylolytic enzymes from several glycoside hydrolase (GH) families GH13, GH14, GH15, GH31, GH57 and GH77, as well as in a number of regulatory enzymes, e.g., phosphoglucan, water dikinase-3, genethonin-1, laforin, starch-excess protein-4, the β-subunit of AMP-activated protein kinase and its homologues from sucrose non-fermenting-1 protein kinase SNF1 complex, and an adaptor-regulator related to the SNF1/AMPK family, AKINβγ. CBM20s and CBM48s of amylolytic enzymes occur predominantly in the microbial world, whereas the non-amylolytic proteins containing these modules are mostly of plant and animal origin. Comparison of amino acid sequences and tertiary structures of CBM20 and CBM48 reveals the close relatedness of these SBDs and, in some cases, glycogen-binding domains (GBDs). The families CBM20 and CBM48 share both an ancestral form and the mode of starch/glycogen binding at one or two binding sites. Phylogenetic analyses demonstrate that they exhibit independent behaviour, i.e. each family forms its own part in an evolutionary tree, with enzyme specificity (protein function) being well represented within each family. The distinction between CBM20 and CBM48 families is not sharp since there are representatives in both CBM families that possess an intermediate character. These are, for example, CBM20s from hypothetical GH57 amylopullulanase (probably lacking the starch-binding site 2) and CBM48s from the GH13 pullulanase subfamily (probably lacking the starch/glycogen-binding site 1). The knowledge gained concerning the occurrence of these SBDs and GBDs through the range of taxonomy will support future experimental research. © 2011 Elsevier Inc.

Samaj L.,Slovak Academy of Sciences | Samaj L.,University Paris - Sud | Trizac E.,University Paris - Sud
Contributions to Plasma Physics | Year: 2012

We propose a strong-coupling analysis of a polarizable planar interface, in the spirit of a recently introduced Wigner-Crystal formulation. The system is made up of two moieties: a semi-infinite medium (z < 0) with permittivity ε ′ while the other half space in z > 0 is occupied by a solution with permittivity ε, and mobile counter-ions (no added electrolyte). The interface at z = 0 bears a uniform surface charge. The counter-ion density profile is worked out explicitly for both repulsive and attractive dielectric image cases. © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Foulis D.J.,University of Massachusetts Amherst | Pulmannova S.,Slovak Academy of Sciences
Foundations of Physics | Year: 2013

A synaptic algebra is a generalization of the self-adjoint part of a von Neumann algebra. In this article we extend to synaptic algebras the type-I/II/III decomposition of von Neumann algebras, AW*-algebras, and JW-algebras. © 2013 Springer Science+Business Media New York.

Mucka P.,Slovak Academy of Sciences
Road Materials and Pavement Design | Year: 2013

The study quantified the influence of the road profile obstacles on 27 different road unevenness indicators (RUI). The influence of obstacle height, length and number of obstacles per kilometre was assessed. The 2997 real longitudinal road-profile records from the Long-Term Pavement Performance program with considering asphalt concrete and cement concrete road surfaces were processed. 5169 obstacles were identified by a median filtering approach and their dimensions were quantified. The regression function based on linear coefficients for dependence of the RUI on three obstacle parameters was derived. The marked dependence of the road indicators on all three obstacle parameters was observed. The road indices describing the short wavelength band proved to be the most sensitive for detecting obstacle presence in a road profile. © 2013 © 2013 Taylor & Francis.

Lacik I.,Slovak Academy of Sciences
Micro and Nanosystems | Year: 2013

This minireview focuses on recent developments in the field of islet microencapsulation as one of the strategies for immunoprotection of transplanted insulin-producing cells for future diabetes treatment. A growing number of peerreviewed publications and reviews in the last few years demonstrate both the progress and strong motivation to identify safe and functional biomaterials. This minireview is primarily based on a literature survey covering the last few years, with the main section devoted to the discussion of various microcapsule types currently under development. The information on microcapsules is complemented by a brief discussion of two additional current strategies used for immunoprotection, namely macroencapsulation and conformal coating, to capture the overall situation in the field of islet encapsulation and transplantation. This is followed by briefly commenting on the characterization of encapsulation devices. In conclusion, the past and very recent achievements (1) reveal that islet microencapsulation remains a vital strategy to protect islet cells and (2) allow for proposing the next steps to bring this strategy closer to clinics. © 2013 Bentham Science Publishers.

Prokop P.,Slovak Academy of Sciences | Fancovicova J.,University of Trnava
Acta Ethologica | Year: 2010

Evolutionary explanations of disgust propensity propose that disgust is an adaptation which helps us to decrease the likelihood of being infected by pathogens. To test this hypothesis, we examined human fear, disgust and self-perceived danger as a response on colourful pictures of disease-relevant and disease-irrelevant invertebrates. Furthermore, we also examined a possible link between these variables and human anti-parasite behaviour. We found that participants clearly distinguished between disease-relevant and disease-irrelevant group of animals, and that females always scored higher than males. Moreover, there were associations between ratings of fear, disgust and danger and human anti-parasite behaviour. Our results support the hypothesis that human emotions and behaviours are shaped by natural selection. © 2010 Springer-Verlag and ISPA.

Hoi H.,Austrian Academy of Sciences | Kristin A.,Slovak Academy of Sciences | Valera F.,CSIC - Estacion Experimental De Zonas Aridas | Hoi C.,Austrian Academy of Sciences
Oecologia | Year: 2012

In order to understand habitat selection, it is important to consider the way individual animals assess the suitability of a future reproductive site. One way of investigating mechanisms (such as those involved in nest site selection) is to examine breeding success and habitat characteristics in terms of animals returning to a place where they have already reproduced and using the same location over successive years or searching for new alternatives. This approach seems especially suitable for testing recent hypotheses suggesting that nest site selection is an integrative process that includes the use of social information (e. g. past breeding success of conspecifics). Determining the factors that elicit conservative or innovative behaviour regarding nest-site selection could be important for improving our understanding of habitat selection decisions in animals. More than half of the nests of the long-distance migratory lesser grey shrike Lanius minor, are built in the same or neighbouring trees. We found no evidence that habitat characteristics influence nest-site tradition. On the contrary, social information in terms of the presence of conspecifics and past reproductive success in terms of complete nest failures due to nest predation (but not detailed information such as variation in fledgling number) influenced nest-site tradition. Hence, social information and past reproductive success may play a role in nest-site choice in this species. Our results further demonstrate that previous experience with a nest site does not appear to be beneficial. © 2011 Springer-Verlag.

Hanel L.,Academy of Sciences of the Czech Republic | Cerevkova A.,Slovak Academy of Sciences
Helminthologia | Year: 2010

Fauna of soil nematodes was studied in three main forest types of the Vihorlat Mountains, Querceto-Fageto-Aceretum at Remetské Hámre (RH), Fagetum at Morské oko (MO), and Fageto-Aceretum at Sninský kameň (SK). Each forest type was represented by five sites. In total 198 species and 98 genera of soil nematodes were distinguished. Most species belonged to rare taxa with the frequency of occurrence lower than 50 %. The number of species and genera decreased from RH (167 species and 86 genera) through MO (115 and 68) to SK (87 and 51). Species and generic richness was significantly positively correlated with soil pH(H2O), negatively with altitude, soil moisture and Cox. Greater part of nematode species and genera belonged to microbivores and to the taxa with higher cp values of 3 - 5. We can conclude that rich nematode fauna indicated undisturbed forest soil condition, nevertheless, the richness decreased with increasing altitude. © 2010 Versita Warsaw and Springer-Verlag Wien.

Sumbalova Z.,University of Sfax | Kucharska J.,University of Sfax | Kristek F.,Slovak Academy of Sciences
Cellular and Molecular Neurobiology | Year: 2010

Increased production of free radicals and impairment of mitochondrial function are important factors in the pathogenesis of hypertension. This study examined the impact of hypertension on mitochondrial respiratory chain function, coenzyme Q 9 (CoQ 9), coenzyme Q 10 (CoQ 10), and α-tocopherol content in brain mitochondria, and the effect of blockade of angiotensin II type 1 receptors (AT1R) in the prehypertensive period on these parameters. In addition, blood pressure, heart and brain weight to body weight ratios, and the geometry of the basilar artery supplying the brain were evaluated. In the 9th week blood pressure and heart weight/body weight ratio were significantly increased and brain weight/body weight ratio was significantly decreased in spontaneously hypertensive rats (SHR) when compared to Wistar rats (WR). The crosssectional area of the basilar artery was increased in SHR. Glutamate-supported respiration, the rate of ATP production, and concentrations of CoQ 9, CoQ 10, and α-tocopherol were decreased in SHR. The succinate-supported function and cytochrome oxidase activity were not changed. The treatment of SHR with losartan (20 mg/kg/day) from 4th to 9th week of age exerted preventive effect against hypertension, heart and arterial wall hypertrophy, and brain weight/body weight decline. After the therapy, the rate of ATP production and the concentration of CoQ increased in comparison to untreated SHR. The impairment of energy production and decreased level of lipid-soluble antioxidants in brain mitochondria as well as structural alterations in the basilar artery may contribute to increased vulnerability of brain tissue in hypertension. Long-term treatment with AT1R blockers may prevent brain dysfunction in hypertension. © Springer Science+Business Media, LLC 2010.

Serova L.I.,New York Medical College | Laukova M.,New York Medical College | Laukova M.,Slovak Academy of Sciences | Alaluf L.G.,New York Medical College | And 2 more authors.
European Neuropsychopharmacology | Year: 2014

PTSD is a debilitating neuropsychiatric disorder and many patients do not respond sufficiently to current treatments. Neuropeptide Y (NPY) is suggested to provide resilience to the development of PTSD and co-morbid depression. Injections of NPY to the rodent brain are anxiolytic. Recently we showed that intranasal delivery of NPY to rats before or immediately after exposure to single prolonged stress (SPS) animal model of PTSD prevented development of many biochemical and behavioral symptoms of PTSD, indicating its prophylactic potential. Here, we investigated whether intranasal NPY might provide benefits once symptoms have already developed. One week after exposure to SPS stressors, animals were given intranasal NPY or vehicle and tested on elevated plus maze 2. h or 2 days later. The NPY treated rats had lower anxiety-like behavior than vehicle treated rats as indicated by more entries into open arms and fewer into closed arms, lower anxiety index, higher risk assessment and unprotected head dips and reduced grooming time. Their anxiety index was similar to that of unstressed controls. On most of these variables there was no effect of time interval and rats displayed similar overall changes 2. h or 2 days after the infusion. Moreover, intranasal NPY led to reduced depressive-like behavior, assessed by forced swim test. Thus, intranasal NPY reversed several behavioral impairments triggered by the traumatic stress of SPS and has potential for non-invasive PTSD therapeutic intervention. © 2013 Elsevier B.V. and ECNP.

Reith D.,Johannes Gutenberg University Mainz | Cifra P.,Slovak Academy of Sciences | Stasiak A.,University of Lausanne | Virnau P.,Johannes Gutenberg University Mainz
Nucleic Acids Research | Year: 2012

Observation that DNA molecules in bacteriophage capsids preferentially form torus type of knots provided a sensitive gauge to evaluate various models of DNA arrangement in phage heads. Only models resulting in a preponderance of torus knots could be considered as close to reality. Recent studies revealed that experimentally observed enrichment of torus knots can be qualitatively reproduced in numerical simulations that include a potential inducing nematic arrangement of tightly packed DNA molecules within phage capsids. Here, we investigate what aspects of the nematic arrangement are crucial for inducing formation of torus knots. Our results indicate that the effective stiffening of DNA by the nematic arrangement not only promotes knotting in general but is also the decisive factor in promoting formation of DNA torus knots in phage capsids. © 2012 The Author(s).

Mesiarova-Zemankova A.,Slovak Academy of Sciences
Fuzzy Sets and Systems | Year: 2016

Extensions of several concepts for definition of capacities given by a small number of parameters in the unipolar and bipolar framework to the case of multi-polar input spaces are studied. The paper covers decomposable, symmetric, category symmetric, additive, reduced additive and k-additive multi-(polar) capacities and discusses its properties. The multi-polar Möbius transform of multi-polar capacities is introduced and its properties for coordinate-wisely given, additive and k-additive multi-polar capacities are described. © 2015 Elsevier B.V.

Syringes are the most expensive consumables for analyses in the Liquid Water Isotope Analyser using commercial Cavity Ring-Down Spectroscopy (CRDS) systems. Our experience shows that although the syringe life significantly varies, it is not an exception that a syringe performs many thousands of injections. A simple maintenance procedure consisting of replacing the syringes two times per day and keeping them in the deionised water resulted in an average syringe life of over 3500 injections. Number of injections per sample affects the between-sample memory effect and the cost of the analysis (duration, energy, consumption of syringes). We studied the influence of the number of injections (six and nine) on the final δ18O and δ2H values using two sets of samples covering the ranges of isotopic composition typical for the natural waters of the highest part of the Carpathians (streams, springs, soil water and precipitation). The differences in the final δ-values between nine and six injections were within 0.1 ‰ for δ18O and 1.0 ‰ for δ2H for the Picarro 2120i and 2130i CRDS systems. © 2015 Taylor & Francis

The aim of the study presented in the paper was to determine standards of quality for outdoor recreation in Tatra National Park in Slovakia. A survey was carried out in two nature reserves in the park, Mlynická Valley and Studené Valleys, during the 2012 and 2013 summer seasons. The questionnaire focused on several topics relevant for visitor management. In this paper we present partial results of the survey, focusing on visual simulations for crowding and vegetation loss. Findings from both study areas point towards the need for management action since preferred conditions for both indicators had been exceeded. © all photographs by the authors.

Mesiarova-Zemankova A.,Slovak Academy of Sciences
Soft Computing | Year: 2016

The fuzzy rule-based classifier can be taken as a function that assigns to a point from the feature space a class, or a class with an association degree. Under this assumption, the robustness of fuzzy rule-based classifiers is investigated by means of the Lipschitz condition. The Lipschitz continuity of fuzzy sets, fuzzy rules and whole fuzzy rule-based classifiers is examined for multi-polar outputs, extended multi-polar outputs and outputs in the form of a class. Related performance of a fuzzy rule-based classifier is also discussed. All studied concepts are shown on an exemplar fuzzy rule-based classifier. © 2015, Springer-Verlag Berlin Heidelberg.

Puliova P.,Park University | Puliova P.,Academy of Sciences of the Czech Republic | Kovac J.,Slovak Academy of Sciences | Voigt A.,Otto Von Guericke University of Magdeburg | Raschman P.,Park University
Journal of Magnetism and Magnetic Materials | Year: 2013

Nano-particles of CoFe2O4, NiFe2O 4 and Co0.5Ni0.5Fe2O4 were synthesized by a two step microemulsion precipitation where inverse micelles of water in hexanol were stabilized using cetyltrimethylammonium bromide. Powder X-ray diffraction analysis and Transmission electron microscopy measurements provided data to clarify the crystal structure and size of the produced nano-particles. Different measurements of magnetic properties at low temperatures of 2 K revealed that nano-particles of NiFe2O4 represent magnetically soft ferrite with a coercivity -40 kA!m, whereas nano-particles of CoFe 2O4 and Coo.5Nio5Fe2O4 were magnetically harder with a coercivity of 815 and 947 kA!m, respectively. Additionally zero field cooling and field cooling measurements provided data for estimating the blocking temperature of the materials produced. For NiFe 2O4 this temperature is lower, 23 K. The blocking temperature of CoFe2O4 of 238 K and Co0.5Ni0.5Fe 2O4 of 268 K are higher in comparison with NiFe 2O4. © 2013 Elsevier B.V. All rights reserved.

Pey A.L.,University of Granada | Majtan T.,Aurora University | Majtan T.,Slovak Academy of Sciences | Sanchez-Ruiz J.M.,University of Granada | Kraus J.P.,Aurora University
Biochemical Journal | Year: 2013

CBS (cystathionine β-synthase) is a multidomain tetrameric enzyme essential in the regulation of homocysteine metabolism, whose activity is enhanced by the allosteric regulator SAM (S-adenosylmethionine). Missense mutations in CBS are the major cause of inherited HCU (homocystinuria). In the present study we apply a novel approach based on a combination of calorimetric methods, functional assays and kinetic modelling to provide structural and energetic insight into the effects of SAM on the stability and activity of WT (wild-type) CBS and seven HCU-causing mutants. We found two sets of SAM-binding sites in the C-terminal regulatory domain with different structural and energetic features: a high affinity set of two sites, probably involved in kinetic stabilization of the regulatory domain, and a low affinity set of four sites, which are involved in the enzyme activation. We show that the regulatory domain displays a low kinetic stability in WT CBS, which is further decreased in many HCU-causing mutants. We propose that the SAM-induced stabilization may play a key role in modulating steady-state levels of WT and mutant CBS in vivo. Our strategy may be valuable for understanding ligand effects on proteins with a complex architecture and their role in human genetic diseases and for the development of novel pharmacological strategies. © The Authors Journal compilation © 2013 Biochemical Society.

Sabbah I.,Alexandria University | Kudela K.,Slovak Academy of Sciences
Journal of Geophysical Research: Space Physics | Year: 2011

Spectral analysis of neutron monitors and muon telescope daily averages counts shows a significant higher harmonic (∼9 day) of the 27 day variation of galactic cosmic rays (CRs). This quasiperiodicity is also present in the time series of daily averages of the product of interplanetary magnetic field magnitude and the square of solar wind speed (BV2). The wavelet spectrum density of the third harmonic of the 27 day variation of CRs is weakly correlated with the quantity BV2. This result reflects the coupling between galactic CR modulation and interplanetary parameters. Copyright 2011 by the American Geophysical Union.

Pohanka V.,Slovak Academy of Sciences
Contributions to Geophysics and Geodesy | Year: 2011

We calculate the gravitational intensity and potential of a homogeneous body with the shape of the rotational ellipsoid. The calculation is performed in ellipsoidal coordinates and uses the properties of harmonic functions expressed as ellipsoidal harmonics. The resulting formulae for the internal and external fields are expressed in ellipsoidal coordinates and (in the case of external field) also in spherical coordinates. The results are used in the calculation of the gravitational field of a layered body whose layer boundaries are rotational ellipsoids with common centre and rotational axis; the density in each layer is constant. The equilibrium of such a layered rotating body is examined: it is found that there is no equilibrium for such a body except the case that the body is homogeneous (thus proving once more the important, but rarely mentioned, fact).

Hricoviniova Z.,Slovak Academy of Sciences
Carbohydrate Polymers | Year: 2013

The influence of microwave irradiation on hydrolysis of xylan and simultaneous epimerization of the d-xylose to d-lyxose has been studied. An acidic solution of xylan was treated with catalytic amount of sodium molybdate and the composition of the reaction mixture was analyzed. Short reaction times of hydrolysis and subsequent epimerization reaction provided an equilibrium reaction mixture of d-xylose and d-lyxose (1.6:1) without significant formation of undesirable side products. Obtained pentoses can be reduced to the corresponding alditols (d-xylitol and d-lyxitol) in very good yields (88% and 85%) or can be further dehydrated to furfural (53%). Combined use of Mo(VI) catalyst and microwave irradiation allows better conversions and substantial reduction of reaction times (400-fold) compared to that obtained by conventional heating. Studied stereospecific transformation of xylan proceeds with high selectivity, short reaction times and very good yields that makes this approach attractive also for preparative purposes. © 2013 Elsevier Ltd. All rights reserved.

Janisova M.,Slovak Academy of Sciences | Bartha S.,Hungarian Academy of Sciences | Kiehl K.,Osnabruck University of Applied Sciences | Dengler J.,University of Hamburg
Plant Biosystems | Year: 2011

Dry grasslands in Europe are mostly of zoo-anthropogenic origin, but nevertheless they are among the most diverse plant communities of the world at small spatial scales, and they support a significant proportion of the biodiversity of the continent. Both agricultural intensification and abandonment of former dry grasslands caused dramatic losses in area and quality of this habitat type during recent decades. Here we report from the 7th European Dry Grassland Meeting, organised by the European Dry Grassland Group (EDGG) in Smolenice, Slovakia, in 2010. Under the motto "Succession, restoration and management of dry grasslands" one hundred researchers from throughout Europe discussed conservation issues of this threatened habitat type. We give a brief introduction to those nine articles that are included in this Special Feature. With contributions from many different countries and various dry grassland types, they address issues of conservation value, succession, management as well as regeneration and restoration. We conclude that the diversity of dry grasslands and their conservation problems require further research to develop adequate management techniques under changing frame conditions. However, also the frame conditions, such as the incentives for certain land use practices provided by the Common Agricultural Policy of the European Union need to be addressed if long-term success in conservation of dry grasslands is intended. © 2011 Società Botanica Italiana.

Mesiarova-Zemankova A.,Slovak Academy of Sciences
IEEE Transactions on Fuzzy Systems | Year: 2014

The reasoning methods in fuzzy rule-based classification systems are studied, and their relation to multipolar aggregation operators is discussed. We describe the change in the output of the classification system based on the change of the fuzzy reasoning method. We propose a new fuzzy reasoning method based on multipolar fusion OWA operator which can control the transition between the maximum rule method and the maximum vote method by a weighting vector. This new method uses principles of OWA operators and assigns the rule weight according to the strength of activation of the rule. We compare different fuzzy reasoning methods in case studies. © 2014 IEEE.

Lichvarova L.,Slovak Academy of Sciences
General physiology and biophysics | Year: 2012

Neuronal growth factor (NGF) induces neurodifferentiation of PC12 cells into cholinergic neurons-like cells. It was shown that intracellular Ca2+ ions participate in regulation of the differentiation of PC12 cells. We tested whether L-type calcium channels contribute to Ca2+ entry which supports neurite outgrowth accompanying NGF-activated differentiation process. Development of morphological changes did correlate with increase of functional expression of L-type calcium channels. However, inhibition of L-type calcium channels by 1 μM of isradipine did not affect significantly an NGF-activated neurite outgrowth.

Orlicky O.,Slovak Academy of Sciences
Contributions to Geophysics and Geodesy | Year: 2011

The results of the study of young rhyodacites (erupted in 1400 year) from the Haruna area (Japan) and from the 1991 Pinatubo eruption (Philippines) are presented. The experimental works have proven that the Fe-Ti ferrimagnetic-antiferromagnetic phase is the carrier of the self-reversed remanent magnetization in these rocks. The theoretical solution of this problem has been outlined, but has not yet been accomplished.

Hajdukova M.,Slovak Academy of Sciences | Kornos L.,Comenius University | Toth J.,Comenius University
Meteoritics and Planetary Science | Year: 2014

Hyperbolic meteor orbits from the catalog of 64,650 meteors observed by the multistation video meteor network located in Japan (SonotaCo 2009) have been investigated with the aim of determining the relation between the frequency of hyperbolic and interstellar meteors. The proportion of hyperbolic meteors in the data decreased significantly (from 11.58% to 3.28%) after a selection of quality orbits, which shows its dependence on the quality of observations. Initially, the hyperbolic orbits were searched for meteors unbound due to planetary perturbation. It was determined that 22 meteors from the 7489 hyperbolic orbits in the catalog (and 2 from the selection of the orbits with the highest quality) had had a close encounter with a planet, none of which, however, produced essential changes in their orbits. Similarly, the fraction of hyperbolic orbits in the data, which could be hyperbolic by reason of a meteor's interstellar origin, was determined to be at most 3.9 × 10-2. From the statistical point of view, the vast majority of hyperbolic meteors in the database have definitely been caused by inaccuracy in the velocity determination. This fact does not necessarily assume great measurement errors, since, especially near the parabolic limit, a small error in the value of the heliocentric velocity of a meteor can create an artificial hyperbolic orbit that does not really exist. The results show that the remaining 96% of meteoroids with apparent hyperbolic orbits belong to the solar system meteoroid population. This is also supported by their high abundance (about 50%) among the meteor showers. © The Meteoritical Society, 2013.

Capek I.,Slovak Academy of Sciences
Advances in Colloid and Interface Science | Year: 2011

Many biomolecules have specific binding properties in the nanostructure formation; they are attractive materials for nanotechnology. One such promising construction material for growing a well-defined nanostructure is deoxyribonucleic acid, due to its π-electron hydrophobic core and predictable recognition attributed to the specificity of Watson-Crick base-pairing. Hydrogen bonding provides the specificity behind the matching of complementary pairs of single-stranded (ss) DNA to hybridize into a double strand (ds) of helical DNA. The double-helical structure of DNA is determined by a subtle balance of noncovalent interactions among the DNA building blocks. The most prominent role is played by the interactions between the DNA bases, where two binding motifs can be recognized: planar hydrogen bonding and vertical stacking. DNA-based nanotechnology has generated interest in a number of applications due to the specificity, programmability, and reproducibility of DNA interaction with noble metal nanoparticles. 5′ and 3′ thiol moieties are used to prepare composite DNAs, DNA-gold nanoparticle conjugates and nanostructures with a variety of nanoparticle-based DNA assays. Particularly, color changes induced by the association of nanometer-sized gold particles provide a basis of a simple yet highly selective method for detecting specific biological reactions between anchored ligand molecules and receptor molecules in the milieu. Colloidal noble metal nanoparticles, in particular, have found application in a variety of assay formats in which analyte binding is coupled to particle adsorption. The extreme sensitivity of the bandwidth, the peak height, and the position of the absorption (or scattering) maximum of surface plasmon resonance spectra to environmental changes have prompted the development of approaches directly monitor the DNA hybridization. The same features that make DNA an effective molecule for the storage of genetic information also render it useful as an engineering material for the construction of smart objects at the nanometer scale because of its ability to self organize into desired structures via the specific hybridization of complementary sequences. Biocompatibility between gold nanomaterials and biological scaffolding is crucial to the development of smart biomaterials. These DNA/metal colloids are interesting for their fundamental properties as well as for applications in nanomaterials science and nanobiotechnology. © 2011 Elsevier B.V. All rights reserved.

Schouwink P.,University of Geneva | Ley M.B.,University of Aarhus | Jensen T.R.,University of Aarhus | Smrcok L.,Slovak Academy of Sciences | Cerny R.,University of Geneva
Dalton Transactions | Year: 2014

The five novel compounds ALiM(BH4)4 (A = K or Rb; M = Mg or Mn) and K3Li2Mg2(BH4) 9 crystallizing in the space groups Aba2 and P2/c, respectively, represent the first two-dimensional topologies amongst homoleptic borohydrides. The crystal structures have been solved, refined and characterized by synchrotron X-ray powder diffraction, neutron powder diffraction and solid-state DFT calculations. Minimal energies of ordered models corroborate crystal symmetries retrieved from diffraction data. The layered Li-Mg substructure forms negatively charged uninodal 4-connected networks. It is shown that this connectivity cannot generate the long sought-after, bimetallic Li-Mg borohydrides without countercations when assuming preferred coordination polyhedra as found in Mg(BH4)2 and LiBH4. The general properties of the trimetallic compound series are analogous with the anhydrous aluminosilicates. Additionally, a relationship with zeolites is suggested, which are built from three-dimensional Al-Si-O networks with a negative charge on them. The ternary metal borohydride systems are of interest due to their potential as novel hydridic frameworks and will allow exploration of the structural chemistry of light-metal systems otherwise subject to eutectic melting. This journal is © the Partner Organisations 2014.

Benedek R.,Argonne National Laboratory | Thackeray M.M.,Argonne National Laboratory | Low J.,Argonne National Laboratory | Bucko T.,Comenius University | And 2 more authors.
Journal of Physical Chemistry C | Year: 2012

Constrained density functional theory at the GGA+U level, within the Blue Moon ensemble, as implemented in the VASP code, is applied to simulate aqueous dissolution of lithium manganate spinel, a candidate cathode material for lithium ion batteries. Ions are dissolved from stoichiometric slabs of composition LiMn 2O 4, with orientations (001) and (110), embedded in a cell with 20 Å water channels between periodically repeated slabs. Analysis of the Blue Moon ensemble forces for dissolution of Li, Mn, and O ions from lithium manganate indicate that bond breaking occurs sequentially, ordered from weak to strong bonds, where bond breaking occurs when a bond length is stretched about 50% relative to its equilibrium value. Substrate ions are displaced to maintain bond lengths close to equilibrium for bonds other than that the one being broken. The predicted free energies required to break the chemical bonds with the LiMn 2O 4 substrate are Mn 3+, 1.4; O 2-, 1.0; Mn 2+, 0.8; and Li +, 0.35, in eV; an existing experimental measurement (Lu, C. H.; Lin, S. W. J. Mater. Res.2002, 17, 1476) had yielded an effective dissolution activation energy of 0.7 eV. A mechanism for the role of acid in promoting lithium manganate dissolution is discussed. © 2012 American Chemical Society.

The 81-aa Vpu protein of Human immunodeficiency virus 1 (HIV-1) is a structural analogue of the M2 protein of Influenza A virus (IAV). Expression of Vpu in Xenopus oocytes has showed that it can form a voltage-activated ion channel permeable to Na+ and K+ions (Ewart et al., 1996). To investigate whether Vpu has a pH-modulating activity comparable to that of M2, Vpu was co-expressed with the pH-sensitive hemagglutinin (HA) from IAV. The results indicated that Vpu was unable to reduce the acidity of the exocytic pathway and reduce the conversion of the pH-sensitive HA to its low-pH conformation during transport to the cell surface. Despite these findings, we did not exclude the possibility that Vpu formed a weak ion channel with almost pore-like characteristics as was recently suggested.

Capek I.,Slovak Academy of Sciences
Advances in Colloid and Interface Science | Year: 2015

Virus-based nanotechnology has generated interest in a number of applications due to the specificity of virus interaction with inorganic and organic nanoparticles. A well-defined structure of virus due to its multifunctional proteinaceous shell (capsid) surrounding genomic material is a promising approach to obtain nanostructured materials. Viruses hold great promise in assembling and interconnecting novel nanosized components, allowing to develop organized nanoparticle assemblies. Due to their size, monodispersity, and variety of chemical groups available for modification, they make a good scaffold for molecular assembly into nanoscale devices. Virus based nanocomposites are useful as an engineering material for the construction of smart nanoobjects because of their ability to associate into desired structures including a number of morphologies. Viruses exhibit the characteristics of an ideal template for the formation of nanoconjugates with noble metal nanoparticles. These bioinspired systems form monodispersed units that are highly amenable through genetic and chemical modifications. As nanoscale assemblies, viruses have sophisticated yet highly ordered structural features, which, in many cases, have been carefully characterized by modern structural biological methods. Plant viruses are increasingly being used for nanobiotechnology purposes because of their relative structural and chemical stability, ease of production, multifunctionality and lack of toxicity and pathogenicity in animals or humans. The multifunctional viruses interact with nanoparticles and other functional additives to the generation of bioconjugates with different properties - possible antiviral and antibacterial activities. © 2014 Elsevier B.V. All rights reserved.

Martinovic L.,Slovak Academy of Sciences
Few-Body Systems | Year: 2014

We discuss a few new results within the exactly solvable relativistic models studied in both the conventional and the light front field theory. The models include the Rothe-Stamatescu, the Thirring, the Federbush and the Thirring-Wess model. The unifying feature is that the corresponding field equations are solved in a simple and exact form. We work within the hamiltonian framework and pay a careful attention to the correct definition of interacting currents which are built from the known solutions in a point-split regularized manner. Quantum "anomalies" follow immediately. The Hamiltonians of the models are expressed in terms of the correct (dynamically independent) field variables, namely the free Heisenberg fields. Due to the simplicity of the models' dynamics, one can explicitly determine structure of the physical ground states. © 2014 Springer-Verlag Wien.

Heat shock 70kDa protein 9 (HSPA9)/mortalin is a heat-uninducible member of the heat shock 70 protein family. This protein has been attributed many cellular functions, including energy generation, stress response, carcinogenesis and involvement in neurodegenerative diseases, which is well documented by many names it has been given (CSA, MOT, MOT2, GRP75, PBP74, GRP-75, HSPA9B, MGC4500, MTHSP75, and mortalin). As an immortalization marker (hence the name "mortalin") in mouse embryonic fibroblasts cybrids it preferentially segregated with loss of immortality in passaged cells. Mortalin regulates the functions of the tumor suppressor protein p53 and plays important roles in stress response and maintenance of the mitochondria and endoplasmic reticulum. Furthermore, mortalin appears to have roles in membrane trafficking and viral release regulation, since it interacts with Nef protein it is necessary for secretion of exosomal negative factor (Nef) and HIV-1 virus release. Recently, mortalin has been described as a significant player in neurodegenerative diseases. Mutations in HSPA9 gene have been found in Parkinson's disease patients; mortalin isoform expression differs in hippocampus of patients with Alzheimer's disease and could regulate the β-amyloid toxicity pathway. In this review we summarize the functions of mortalin, its pathological implications in neuronal dysfunction and possible roles in neurodegenerative diseases. Keywords: HSPA9/mortalin/GRP75; mitochondria; cancer; Alzheimer's disease.

Di Nola A.,University of Salerno | Dvurecenskij A.,Slovak Academy of Sciences | Lettieri A.,University of Naples Federico II
International Journal of Approximate Reasoning | Year: 2010

In [4,5] the authors introduced the variety SMV of MV-algebras with an internal operator, state MV-algebras. In [2,3] the authors gave a stronger version of state MV-algebras, called state-morphism MV-algebras. In this paper we continue the studies presented in [2,3] just looking at several proper subvarieties of SMV, obtained by imposing suitable conditions on the behavior of the internal operator. © 2010 Elsevier Inc. All rights reserved.

Harra L.K.,UCL Mullard Space Science Laboratory | Sterling A.C.,NASA | Sterling A.C.,Japan Aerospace Exploration Agency | Gomory P.,Slovak Academy of Sciences | Veronig A.,University of Graz
Astrophysical Journal Letters | Year: 2011

We observed a coronal wave (EIT wave) on 2011 February 16, using EUV imaging data from the Solar Dynamics Observatory/Atmospheric Imaging Assembly (AIA) and EUV spectral data from the Hinode/EUV Imaging Spectrometer (EIS). The wave accompanied an M1.6 flare that produced a surge and a coronal mass ejection (CME). EIS data of the wave show a prominent redshifted signature indicating line-of-sight velocities of 20kms-1 or greater. Following the main redshifted wave front, there is a low-velocity period (and perhaps slightly blueshifted), followed by a second redshift somewhat weaker than the first; this progression may be due to oscillations of the EUV atmosphere set in motion by the initial wave front, although alternative explanations may be possible. Along the direction of the EIS slit the wave front's velocity was 500kms -1, consistent with its apparent propagation velocity projected against the solar disk as measured in the AIA images, and the second redshifted feature had propagation velocities between 200 and 500kms-1. These findings are consistent with the observed wave being generated by the outgoing CME, as in the scenario for the classic Moreton wave. This type of detailed spectral study of coronal waves has hitherto been a challenge, but is now possible due to the availability of concurrent AIA and EIS data. © 2011. The American Astronomical Society. All rights reserved..

Lieskovsky J.,Slovak Academy of Sciences
Acta Universitatis Carolinae, Geographica | Year: 2011

This paper describes the evaluation of the anti-erosion effect of vineyards, represented by the Universal Soil Loss Equation (USLE), covermanagement factor (C factor), and support practice factor (P factor). The calculations are based on measured soil loss data. The erosion and deposition rates were evaluated from aboveground vineyard poles as their exposure lengths change between the year of vineyard plantation and the year of measurement. The lengths increased on the erosion areas, because the soil had been washed away. On the deposition areas the poles had been covered by soil, so the exposed lengths for aboveground poles decreased. The measurements were taken in Horný Ohaj vineyards, which belong to the Vráble viticultural district. The calculations were based on a comparison between the measured erosion, and the erosion modelled with USLE model. The cover management factor was evaluated for ploughed vineyard. Different C factor values were substituted to the USLE until the root mean squared error between measured and modelled data was minimal.The support practice factor for hoed and rotavatored vineyard was calculated simultaneously.The cover-management factor was determined to 0.692.The support practice factor for ploughed vineyard is 1.000, for hoed vineyard is 0.586, and for rotavatored vineyard is 0.719.

Masan P.,Slovak Academy of Sciences | Halliday B.,CSIRO
Zootaxa | Year: 2014

The family Pachylaelapidae Berlese, 1913 (Acari: Mesostigmata) includes a total of 16 valid and adequately described genera, namely Chaetodellus Mašán & Halliday, 2013, Elaphrolaelaps Berlese, 1910, Mirabulbus Liu & Ma, 2001, Neopachylaelaps Mašán, 2007, Olopachys Berlese, 1910, Onchodellus Berlese, 1904, Pachydellus Mašán, 2007, Pachyglobolaelaps Mašán, new genus, Pachylaelaps Berlese, 1888, Pachylaelapsoides Mašán, 2007, Pachyseiulus Moraza & Johnston, 1990, Pachyseius Berlese, 1910, Pachysphaerolaelaps Mašán, 2007, Paralaelaps Trägardh, 1908, Pseudopachys Berlese, 1916 and Sphaerolaelaps Berlese, 1903. Three of these genera include subgenera, namely Elaphrolaelaps (Incisosternum) Elsen, 1974, Olopachys (Olopachylaella) Mašán, 2007 and Pachylaelaps (Longipachylaelaps) Mašán, 2007. The family is classified here into three subfamilies, Pachyseiinae Karg, 1971 including Pachyseius and Mirabulbus; Pachyseiulinae Mašán, 2007 including Pachyseiulus and Pseudopachys; and Pachylaelapinae Berlese, 1913, with all the other genera. Pachylaelapinae is further divided into three tribes, Pachylaelapini, Paralaelapini and Onchodellini. Almost half of the known genera are monotypic: Neopachylaelaps, Pachyglobolaelaps, Pachylaelapsoides, Pachyseiulus, Pachysphaerolaelaps, Pseudopachys and Sphaerolaelaps, while Onchodellus and Pachylaelaps are the largest genera in the family. Eleven genera that were provisionally classified as Pachylaelapidae cannot be reliably placed into a family on the basis of the available information, or have been incorrectly placed in the Pachylaelapidae: Actinoseius Berlese, 1916, Beaurieuia Oudemans, 1929, Brachylaelaps Berlese, 1910, Bulbogamasus Gu, Wang & Duan, 1991, Megalolaelaps Berlese, 1892, Meliponapachys Turk, 1948, Neoparasitus Oudemans, 1901, Pachylaella Berlese, 1916, Platylaelaps Berlese, 1905, Pseudolaelaps Berlese, 1916 and Zygoseius Berlese, 1916. New synonymies are established for Pseudoparasitus (Pseudopachys) parasitizans Berlese, 1916 (= Pseudopachyseiulus ignacii Moraza & Johnston, 1993) and Pseudopachys Berlese, 1916 (= Pseudopachyseiulus Moraza & Johnston, 1993). Brachylaelaps and Pachylaella are here considered as genera of Neoparasitidae and Macrochelidae respectively, rather than Pachylaelapidae. The genus Mirabulbus is redefined and transferred from Bulbogamasidae to Pachyseiinae. Paralaelaps and Elaphrolaelaps are provisionally placed together in the Pachylaelapinae and the new tribe Paralaelapini. Altogether 44 new combinations are proposed. Onchodellus slovacus Mašán and Pachyglobolaelaps hallidayi Mašán are introduced as new species. Mašán (2007a) described these species but did not designate holotypes for them, so their names are not available from that date. Replacement names are proposed for five junior homonyms: (1) Onchodellus michaelcostai Mašán & Halliday, replacement name for Pachylaelaps brevis Costa, 1971, junior homonym of Pachylaelaps brevis Berlese, 1920; (2) Onchodellus morazae Mašán & Halliday, replacement name for Pachylaelaps minutus Moraza & Peña, 2005, junior homonym of Pachylaelaps minutus Oudemans, 1901; (3) Pachylaelaps atlanticus Mašán & Halliday, replacement name for Pachylaelaps major Van Driel, Loots & Marais, 1977, junior homonym of Pachylaelaps (Paralaelaps) major Berlese, 1918; (4) Pachylaelaps schweizeri Mašán & Halliday, replacement name for Pachylaelaps latus Schweizer, 1961, junior homonym of Pachylaelaps (Platylaelaps) latus Berlese, 1905; and (5) Pachylaelaps similis Mašán & Halliday, replacement name for Pachylaelaps reticulata Hafez & Nasr, 1982, junior homonym of Pachylaelaps (Onchodellus) reticulatus Berlese, 1904. We provide a catalogue of the world species of Pachylaelapidae, which includes 253 named species (including synonyms), with details of their authorship, synonyms, nomenclatural and bibliographic details and generic placement. Copyright © 2014 Magnolia Press.

Czachor H.,Polish Academy of Sciences | Lichner L.,Slovak Academy of Sciences
Journal of Hydrology and Hydromechanics | Year: 2013

The aim of this study was to determine the potential development of water sorptivity of soil aggregates by heating. Soil aggregates were sampled from arable layer of 5 Polish soils: Haplic Luvisol 1 from Czesławice, Haplic Luvisol 2 from Wierzchucinek, Haplic Cambisol from Felin, Gleyic Mollic Cambisol from Chylice, and Haplic Phaeozem from Grabiec. Three aggregates of each soil type with minimum diameter between 4 and 10 mm were heated in the oven for at least 3 hours at temperatures 20, 100, 200, 250, and 360°C. After each temperature treatment the soil aggregates were conditioned at the room temperature for 16 hours. Laboratory measurements of water sorptivity of soil aggregates were performed under a negative tension h0 = -2 cm using tension infiltrometer. It was found that the exposure to temperatures between 100 and 200°C tends to decrease water sorptivity of aggregates from all the studied soils but one (Haplic Luvisol 1), followed by about two- to four-fold increase in water sorptivity for exposure to temperatures of 250°C (in Haplic Luvisol 1, Haplic Luvisol 2, and Haplic Phaeozem) or 360°C (in Haplic Cambisol and Gleyic Mollic Cambisol).

Planat M.,FEMTO ST Institute | Saniga M.,Slovak Academy of Sciences | Holweck F.,University of Technology of Belfort - Montbeliard
Quantum Information Processing | Year: 2013

Disregarding the identity, the remaining 63 elements of the generalized three-qubit Pauli group are found to contain 12096 distinct copies of Mermin's magic pentagram. Remarkably, 12096 is also the number of automorphisms of the smallest split Cayley hexagon. We give a few solid arguments showing that this may not be a mere coincidence. These arguments are mainly tied to the structure of certain types of geometric hyperplanes of the hexagon. It is further demonstrated that also an (182, 123) -type of magic configurations, recently proposed by Waegell and Aravind (J Phys A Math Theor 45:405301, 2012), seems to be intricately linked with automorphisms of the hexagon. Finally, the entanglement properties exhibited by edges of both pentagrams and these particular Waegell-Aravind configurations are addressed. © 2013 Springer Science+Business Media New York.

Lamphar H.S.,Slovak Academy of Sciences | Kundracik F.,Comenius University
Lighting Research and Technology | Year: 2014

In recent years, the scientific community has shown an increased interest in sky glow research. This has revealed an increased need for automated technology that enables continuous evaluation of sky glow. As a result, a reliable low-cost platform has been developed and constructed for automating sky glow measurement. The core of the system is embedded software and hardware managed by a microcontroller with ARM architecture. A monolithic photodiode transimpedance amplifier is used to allow linear light measurement. Data from the diode are collected and used to arrange the exposure time of every image captured by the digital single-lens reflex camera. This proposal supports experimenters by providing a low-cost system to analyse sky glow variations overnight without a human interface. © 2013 The Chartered Institution of Building Services Engineers.

Janak M.,Slovak Academy of Sciences | Van Roermund H.,University Utrecht | Majka J.,Uppsala University | Gee D.,Uppsala University
Gondwana Research | Year: 2013

The first evidence for ultrahigh-pressure (UHP) metamorphism in the Seve Nappe Complex of the Scandinavian Caledonides is recorded by kyanite-bearing eclogite, found in a basic dyke within a garnet peridotite body exposed close to the lake Friningen in northern Jämtland (central Sweden). UHP metamorphic conditions of ~. 3. GPa and 800. °C, within the stability field of coesite, are constrained from geothermobarometry and calculated phase equilibria for the peak-pressure assemblage garnet. +. omphacite. +. kyanite. +. phengite. A prograde metamorphic evolution from a lower P-T (1.5-1.7. GPa and 700-750. °C) stage during subduction is inferred from inclusions of pargasitic amphibole, zoisite and kyanite in garnet cores. The post-UHP evolution is constrained from breakdown textures, such as exsolutions of kyanite and silica from the Ca-Eskola clinopyroxene. Near isothermal decompression of eclogite to lower crustal levels (~. 0.8-1.0. GPa ) led to formation of sapphirine, spinel, orthopyroxene and diopside at granulite facies conditions. Published age data suggest a Late Ordovician (460-445. Ma) age of the UHP metamorphism, interpreted to be related to subduction of Baltoscandian continental margin underneath an outboard terrane, possibly outermost Laurentia, during the final stages of closure of the Iapetus Ocean. The UHP rocks were emplaced from the hinterland collision zone during Scandian thrusting of the nappes onto the Baltoscandian foreland basin and platform. The record of P-T conditions and geochonological data from UHP rocks occurring within the allochthonous units of the Scandinavian Caledonides indicate that Ordovician UHP events may have affected much wider parts of the orogen than previously thought, involving deep subduction of the continental crust prior to final Scandian collision between Baltica and Laurentia. © 2012 International Association for Gondwana Research.

Hricko J.,Slovak Academy of Sciences
23rd International Conference on Robotics in Alpe-Adria-Danube Region, IEEE RAAD 2014 - Conference Proceedings | Year: 2015

Design of small robotic positioning devices is required for some special tasks in field of robotics. In the case that workspace is smaller as 1mm then only compact compliant devices could be utilized. But in the case that straight-line output motion is required too; the design of such devices is more complicated, because the parasitic deformations must be minimized. As suitable solution is seemed combination of principles straight-line devices and compliant mechanisms in design process. This paper deals with design procedures for device based on compact compliant mechanical structure, where kinematical structure of Peaucellier-Lipkin straight-line mechanism was utilized. Design problems of transformation between straight-line mechanisms and flexure structures are discussed. © 2014 IEEE.

Solin L.,Slovak Academy of Sciences
Journal of Flood Risk Management | Year: 2012

In the new paradigm of flood defence, the control of flooding by technical means is supported by an emphasis on the reduction of vulnerability to flooding by economic, social and environmental means. The aim of the present work was to assess the vulnerability of basic urban units (BUUs) located in the headwater basins of Slovakia. Vulnerability was expressed in terms of proxy variables. Using a combination of these variables, specific indices were established. These indices represented the potential for susceptibility to damage, resistance to flooding and resilience after flooding of the social and economic systems in these BUUs. The assessment of vulnerability was based on an application of the multi-atribute decision-making approach. The overall vulnerability of a BUU was calculated via a summation of the specific vulnerability indices. Using visualisation in GIS, the BUUs were grouped into three classes, of low, medium and high vulnerability. Second, evaluation of BUUs from the point of view of expected negative consequences of flooding was done. © 2012 Blackwell Publishing Ltd and The Chartered Institution of Water and Environmental Management (CIWEM).

Corina Ciungu L.,University of Bucharest | Corina Ciungu L.,State University of New York at Buffalo | Dvureenskij A.,Slovak Academy of Sciences
Fuzzy Sets and Systems | Year: 2010

In this paper, we extend the notions of states and measures presented in Dvureenskij and Pulmannová (2000) [12] to the case of pseudo-BCK algebras and study similar properties. We prove that, under some conditions, the notion of a state in the sense of Dvureenskij and Pulmannová (2000) [12] coincides with the Bosbach state, and we extend to the case of pseudo-BCK algebras some results proved by Kühr only for pseudo-BCK semilattices. We characterize extremal states, and show that the quotient pseudo-BCK algebra over the kernel of a measure can be embedded into the negative cone of an archimedean ℓ-group. Additionally, we introduce a Borel state and using results by Kühr and Mundici (2007) [28], we prove a relationship between de Finetti maps, Bosbach states and Borel states. © 2010 Elsevier B.V. All rights reserved.

Kocifaj M.,Slovak Academy of Sciences | Kundracik F.,Comenius University
Solar Energy | Year: 2011

The luminous intensity solid of hollow light guide is determined using an extended HOLIGILM solution. The solution concept enables to simulate luminous intensity solids for various light guides and sky luminance patterns. Angular distribution of light emitted from bottom interface of the light guide strongly depends on how the illumination system is designed. Any beam undergoes many reflection events which influence significantly its direction below the optical interface. As a consequence, the computed luminous intensity solid may show many peak during sunny days. After interaction with tube the light beams suffer from imperfect reflections resulting in non-uniform luminous intensity solid even if the sky luminance is constant. The directionality of the light below the pipe is characterized by asymmetry parameter which is a cosine-weighted integral of luminous intensity. Such a single-value can serve as supplementary parameter that quantifies a measure of downward luminous emissions. © 2011 Elsevier Ltd.

Kowalczewska M.,Jean Moulin University Lyon 3 | Sekeyova Z.,Slovak Academy of Sciences | Raoult D.,Jean Moulin University Lyon 3
Genome Medicine | Year: 2011

Q fever is a worldwide zoonosis caused by Coxiella burnetii. The disease most frequently manifests clinically as a self-limited febrile illness, as pneumonia (acute Q fever) or as a chronic illness that presents mainly as infective endocarditis. The extreme infectivity of the bacterium results in large outbreaks, and the recent outbreak in the Netherlands underlines its impact on public health. Recent studies on the bacterium have included genome sequencing, the investigation of host-bacterium interactions, the development of cellular and animal models of infection, and the comprehensive analysis of different clinical isolates by whole genome and proteomic approaches. Current approaches for diagnosing Q fever are based on serological methods and PCR techniques, but the diagnosis of early stage disease lacks specificity and sensitivity. Consequently, different platforms have been created to explore Q fever biomarkers. Several studies using a combination of proteomics and recombinant protein screening approaches have been undertaken for the development of diagnostics and vaccines. In this review, we highlight advances in the field of C. burnetii proteomics, focusing mainly on the contribution of these technologies to the development and improvement of Q fever diagnostics.

Ivanova H.,Slovak Academy of Sciences
Folia Oecologica | Year: 2015

During an investigation of the mycoflora of Japanese red maple trees growing in an urbanized area of Nitra, Slovakia, Sordaria fimicola (Roberge ex Desm.) Ces. & De Not) was isolated from affected leaves and branches of Acer palmatum ´Atropurpureum´ L. This fungus was associated with symptoms of brown wood discoloration and leaf spottiness of these trees. Sordaria fimicola was recorded for the first time on Acer palmatum ´Atropurpureum´ in Slovakia. The fungus is characterized by dark brown ascomata clothed with setae, fasciculate, unitunicate, cylindrical asci, and olivaceous to olivaceous-brown, one-celled, ellipsoidal, smooth-walled ascospores with a colourless basal germ pore and surrounded by a gelatinous sheath. © 2015, Institute of Forest Ecology SAS.

Krajci M.,Slovak Academy of Sciences | Hafner J.,University of Vienna
Journal of Catalysis | Year: 2014

The activity and selectivity of the polar threefold surfaces of the B20-type intermetallic compound GaPd for the semi-hydrogenation of acetylene to ethylene has been investigated using ab initio density functional theory (DFT). Because of the lack of inversion symmetry, the threefold {1 1 1} surfaces of the B20 structure have polar character, in both nonequivalent [1 1 1] and [1̄1̄1̄] directions several surface terminations differing in structure and chemical composition are possible. The structural and energetic properties and the chemical reactivities of ten conceivable terminations have recently been investigated using DFT (Krajčí and Hafner, 2013) - here detailed atomistic scenarios for the selective semi-hydrogenation of acetylene to ethylene on these surfaces have been developed. Threefold surfaces with only Ga-atoms in the outermost layer are energetically favorable at the Ga-rich end of the interval of the admissible chemical potentials, but they are catalytically inactive because molecular hydrogen cannot be dissociated and hence the hydrogenation of adsorbed hydrocarbon molecules is impossible. Highly corrugated surfaces with Pd atoms in the top atomic plane can hydrogenate adsorbed acetylene molecules easily. But simultaneously their high reactivity with respect to both molecular and atomic hydrogen complicates dissociation and diffusion processes. The selectivity of such surfaces is also insufficient as ethylene molecules adsorbed on-top of highly protruding Pd atoms can be easily attacked by co-adsorbed hydrogen atoms from the bottom. We have found that one of the possible threefold surface terminations with isolated Pd3 triplets and Ga atoms in one-half of the hollows between the Pd3 triplets exhibits both superior catalytic activity and selectivity. However, this surface is energetically competitive only in a very narrow range of chemical potentials. An important factor for achieving a high selectivity is the transition from di-σ bonded adsorption configuration for acetylene to a π-bonded adsorption of ethylene. This transition has also been found in our earlier investigation of the (2 1 0) surface of GaPd as a catalyst for semi-hydrogenation (Krajčí and Hafner, 2012). The large distances between the isolated active sites is also important to avoid undesired side-reactions such as oligomerization. Our results are well compatible with the available experimental observations. We have demonstrated that the observed activity and selectivity of GaPd catalyst originate form contributions from different surfaces terminations differing in activity and selectivity. An optimal selectivity of the catalyst can be achieved only if the formation of surfaces with low selectivity is avoided and terminations with enhanced selectivity are formed. © 2014 Elsevier Inc. All rights reserved.

Majtan T.,University of Colorado at Denver | Majtan T.,Slovak Academy of Sciences | Liu L.,University of Colorado at Denver | Carpenter J.F.,University of Colorado at Denver | Kraus J.P.,University of Colorado at Denver
Journal of Biological Chemistry | Year: 2010

Missense mutations represent the most common cause of many genetic diseases including cystathionine β-synthase (CBS) deficiency. Many of these mutations result in misfolded proteins, which lack biological function. The presence of chemical chaperones can sometimes alleviate or even restore protein folding and activity of mutant proteins. We present the purification and characterization of eight CBS mutants expressed in the presence of chemical chaperones such as ethanol, dimethyl sulfoxide, or trimethylamine-N-oxide. Preliminary screening in Escherichia coli crude extracts showed that their presence during protein expression had a significant impact on the amount of recovered CBS protein, formation of tetramers, and catalytic activity. Subsequently, we purified eight CBS mutants to homogeneity (P49L, P78R, A114V, R125Q, E176K, P422L, I435T, and S466L). The tetrameric mutant enzymes fully saturated with heme had the same or higher specific activities than wild type CBS. Thermal stability measurements demonstrated that the purified mutants are equally or more thermostable than wild type CBS. The response to S-adenosyl-L-methionine stimulation or thermal activation varied. The lack of response of R125Q and E176K to both stimuli indicated that their specific conformations were unable to reach the activated state. Increased levels of molecular chaperones in crude extracts, particularly DnaJ, indicated a rather indirect effect of the chemical chaperones on folding of CBS mutants. In conclusion, the chemical chaperones present in the expression medium were able to fully restore the activity of eight CBS mutants by improving their protein folding. This finding could have direct implications for the development of a therapeutical approach to pyridoxine unresponsive homocystinuria. © 2010 by The American Society for Biochemistry and Molecular Biology, Inc.

Hurai V.,Slovak Academy of Sciences | Paquette J.-L.,University Blaise Pascal | Huraiova M.,Comenius University | Konecny P.,Geological Survey
Journal of Volcanology and Geothermal Research | Year: 2010

Phreatomagmatic eruptions in the Lučenec Basin in Slovakia ejected fragments of igneous rocks of unknown age and ranging in composition from gabbro to syenite and orthopyroxene granodiorite - pincinite. Two kinds of syenites with different Fe3+ contents composed of anorthoclase and interstitial metaluminous trachyte-to-alkali rhyolite glass represent the final products of alkali basalt differentiation at depths of 10 and 15-18km. Pincinite composed of plagioclase, quartz, orthopyroxene, ilmenite and interstitial peraluminous dacite glass is a quenched supersolidus anatectic melt formed at the depth of 17-20km by high-temperature dehydration melting of biotite-bearing gneissic protolith. Zircon from pincinite and syenite, and monazite from syenite were dated using excimer laser ablation ICP-MS. The obtained ages cluster at 5.8 ± 0.1 and 5.4 ± 0.1. Ma, thus corroborating the genetic link between the two rock-types and constraining the residence time of at least 300 ± 100. ka of the parental basalt in the deep crustal magma storage zones. The inferred ages overlap the Upper Miocene-Pliocene boundary, and are considerably younger than spatially associated basaltic lava flows dated using the K/Ar method. Consequently, the fluviolacustrine Poltár Formation overlying the maar structure must have sedimented during the Pliocene and not during the Upper Miocene (Pontian) as previously assumed. © 2010 Elsevier B.V.

Bravyi S.,IBM | Caha L.,Masaryk University | Movassagh R.,Massachusetts Institute of Technology | Nagaj D.,Slovak Academy of Sciences | Shor P.W.,Massachusetts Institute of Technology
Physical Review Letters | Year: 2012

Frustration-free (FF) spin chains have a property that their ground state minimizes all individual terms in the chain Hamiltonian. We ask how entangled the ground state of a FF quantum spin-s chain with nearest-neighbor interactions can be for small values of s. While FF spin-1/2 chains are known to have unentangled ground states, the case s=1 remains less explored. We propose the first example of a FF translation-invariant spin-1 chain that has a unique highly entangled ground state and exhibits some signatures of a critical behavior. The ground state can be viewed as the uniform superposition of balanced strings of left and right brackets separated by empty spaces. Entanglement entropy of one half of the chain scales as 12logn+O(1), where n is the number of spins. We prove that the energy gap above the ground state is polynomial in 1/n. The proof relies on a new result concerning statistics of Dyck paths which might be of independent interest. © 2012 American Physical Society.

Klinovaja J.,University of Basel | Stano P.,University of Basel | Stano P.,Slovak Academy of Sciences | Loss D.,University of Basel
Physical Review Letters | Year: 2012

We study hybrid superconducting-semiconducting nanowires in the presence of Rashba spin-orbit interaction as well as helical magnetic fields. We show that the interplay between them leads to a competition of phases with two topological gaps closing and reopening, resulting in unexpected reentrance behavior. In addition to the topological phase with localized Majorana fermions (MFs) we find new phases characterized by fractionally charged fermion (FF) bound states of Jackiw-Rebbi type. The system can be fully gapped by the magnetic fields alone, giving rise to FFs that transmute into MFs upon turning on superconductivity. We find explicit analytical solutions for MF and FF bound states and determine the phase diagram numerically by determining the corresponding Wronskian null space. We show by renormalization group arguments that electron-electron interactions enhance the Zeeman gaps opened by the fields. © 2012 American Physical Society.

The sedimentary sequence of the Central-Carpathian Paleogene Basin provides proxy records of climatic changes related to cooling events at the Eocene/Oligocene boundary (TEE). In this basin, climatic deterioration is inferred from the demise of the carbonate platform and oligotrophic benthic biota in the SBZ19 and from the last species of warm-water planktonic foraminifers in the E14 Zone. Upper Eocene formations already indicate warm-temperate to cool-temperate productivity and nutrient-enriched conditions (Bryozoan Marls, Globigerina Marls). Rapid cooling during the earliest Oligocene (Oi-1 event) led to a temperature drop (∼11 °C), humidity, fresh water influx and continental runoff, water mass stratification, bottom water anoxia, eutrofication, estuarine circulation and upwelling, carbonate depletion, sapropelitic and biosiliceous deposition, H2S intoxication and mass faunal mortality, and also other characteristics of Black Sea-type basins. Tectonoeustatic events with the interference of TA 4.4 sea-level fall and the Pyrenean phase caused basin isolation at the beginning of the Paratethys. The Early Oligocene stage of Paratethyan isolation is indicated by a stagnant regime, low tide influence, endemic fauna development, widespread anoxia and precipitation of manganese deposits. The episodic rise in the sea-level, less humid conditions and renewed circulation is marked by calcareous productivity, nannoplankton blooms and the appearance of planktic pteropods and re-oxygenation. Paleogeographic differentiation of the Carpatho-Pannonian Paleogene basins resulted from plate-tectonic reorganization during the Alpine orogenesis.

Hricko J.,Slovak Academy of Sciences
International Journal of Mechanics and Control | Year: 2015

Structures of straight-line mechanisms are very often used in building of smart precise robotic devices, to which requirements based on high accuracy and precision with manipulation of micro- and nano- scale objects are put. In this case only compact compliant devices can be used. The parasitic deformations in movement of compliant mechanisms must be minimized, when exact straight-line output motion is required. This put higher requirements to complexity of such devices design. This paper deals with design procedures (conversion) for device based on compact compliant mechanical structure, where kinematical structure of Peaucellier-Lipkin straight-line mechanism was used. Design problems of transformation between straight-line mechanisms and flexure structures are discussed.

Mandakova T.,Masaryk University | Marhold K.,Slovak Academy of Sciences | Marhold K.,Charles University | Lysak M.A.,Masaryk University
New Phytologist | Year: 2014

The origin of Cardamine flexuosa (Wavy Bittercress) has been a conundrum for more than six decades. Here we identify its parental species, analyse its genome structure in comparison to parental genomes and describe intergenomic structural variations in C. flexuosa. Genomic in situ hybridization (GISH) and comparative chromosome painting (CCP) uncovered the parental genomes and the chromosome composition of C. flexuosa and its presumed diploid progenitors. Cardamine flexuosa is an allotetraploid (2n = 4x = 32), originating from two diploid species, Cardamine amara and Cardamine hirsuta (2n = 2x = 16). The two parental species display almost perfectly conserved chromosomal collinearity for seven out of the eight chromosomes. A 13 Mb pericentric inversion distinguishes chromosome CA1 from CH1. A comparative cytomolecular map was established for C. flexuosa by CCP/GISH. Whereas conserved chromosome collinearity between the C. amara and C. hirsuta subgenomes might have promoted intergenomic rearrangements through homeologous recombination, only one reciprocal translocation between two homeologues has occurred since the origin of C. flexuosa. The genome of C. flexuosa demonstrates that allopolyploids can maintain remarkably stable subgenomes over 104-105 yr throughout a wide distribution range. By contrast, the rRNA genes underwent genome-specific elimination towards a diploid-like number of loci. © 2013 New Phytologist Trust.

Adamcik S.,Slovak Academy of Sciences | Buyck B.,French Natural History Museum
Cryptogamie, Mycologie | Year: 2010

R. levyana, R. floridana and R. praerubriceps are three species described by W. A. Murrill that are traditionally interpreted as synonyms of R. xerampelina var. semirubra Singer. As such, these species have never been reported again since their original description. In this paper the authors re-examine and illustrate the type-specimens of these species in detail and come to the conclusion that they represent 3 different species that are not synonymous with Singer's variety. Of these 3 species, only R. levyana belongs in sect. Xerampelinae and a new, modern description is provided based on recent collections from Texas. These specimens represent the first records of Murrill's species since its original description from Florida. © 2010 Adac. Tous droits réservés.

Martinovic Lubomir L.,Slovak Academy of Sciences
Nuclear Physics B - Proceedings Supplements | Year: 2010

Simple two-dimensional models with massless and massive fermions are studied in the Hamiltonian framework. While the ultimate purpose of this study is a comparison between correlation functions constructed from known operator solutions in both space-like and light-front forms of the theory, the main goal at the present stage is to find physical vacuum states of the space-like models as the lowest energy eigenstates of H0+Hint. This can be accomplished, using Klaiber's bosonization of the vector current, by means of a Bogoliubov transformation of the Hamiltonian which is quadratic in effective boson operators composed of fermion bilinears. The massless Thirring model is studied in this way and recent claims about its broken phase are critically examined. A brief discussion of the physical content of the models with derivative coupling is also included. © 2010 Elsevier B.V.

Kona J.,Slovak Academy of Sciences | Fabian W.M.F.,University of Graz
Journal of Chemical Theory and Computation | Year: 2011

The first reaction step of the redox cycle of bovine erythrocyte glutathione peroxidase from class 1 (GPX1) was investigated using hybrid quantum mechanics/molecular mechanics (QM/MM) calculations using the ONIOM methodology. The reduction of hydrogen peroxide by the active-site selenocysteine in selenolate form assisted by the Arg177 residue was modeled based on a proposal from previous molecular dynamics simulations and pK a calculations (J. Chem. TheoryComput. 2010, 6, 1670-1681). The redox reaction is predicted as a concerted S N2 nucleophilic substitution with a concomitant proton transfer from Arg177 onto leaving hydroxide ion upon reduction of hydrogen peroxide. The height of the reaction barrier was predicted in range of 6-11 kcal mol -1, consistent with an experimental rate constant of ca. 10 7 M -1 s -1. The proposed GPX1-Se --Arg177H + mechanism for GPX1 is compared with the GPX3-SeH-Gln83 one proposed for human glutathione peroxidase from class 3 (GPX3) and with the solvent-assisted proton exchange mechanism proposed for GPX-like organic selenols. The structural and energetic parameters predicted by various density functional theory methods (B3LYP, MPW1PW91, MPW1K, BB1K, M05-2X, M06-2X, and M06) are also discussed. © 2011 American Chemical Society.

Jiraskova G.,Slovak Academy of Sciences
Lecture Notes in Computer Science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics) | Year: 2016

We survey recent results on the descriptional complexity of self-verifying finite automata. In particular, we discuss the cost of simulation of self-verifying finite automata by deterministic finite automata, and the complexity of basic regular operations on languages represented by self-verifying finite automata. © IFIP International Federation for Information Processing 2016.

This study was aimed to investigate the therapeutic potential of novel nonclassical antifolate, 2-[N-(2'-Hydroxyethyl)ami-no]methyl-3H-quinazolin-4-one (HEAMQ), toward human promonocytic U937 and murine lymphoblastic L1210 cell lines. The antiproliferative activity of HEAMQ was determined by MTT assay and its effects on cell cycle progression and apoptosis were studied by flow cytometry, and by immunoblots, respectively. In addition, combination chemotherapy of HEAMQ with cisplatin and temozolomide under in vitro and in vivo conditions was tested. HEAMQ showed concentration- and time-dependent cytotoxicity toward U937 and L1210 cells. It induced G2/M arrest that in U937 cells was associated with a marked decrease in the protein expressions of cyclin A, cyclin B, and cyclin-dependent kinase Cdk1. HEAMQ-induced apoptosis was accompanied with up-regulation of the protein expression of Bax and down-regulation of the protein expression of Bcl-2, Mcl-1, XIAP, and survivin, resulting in cytochrome c release and activation of caspases. Inhibitors of JNK (SP600125) and p38 MAPK (SB203580) suppressed HEAMQ-induced apoptosis and G2/M phase arrest, attenuated the activation of Bax, and blocked down-regulation of Bcl-2, XIAP and survivin in HEAMQ-treated U937 cells. In addition, combinations of HEAMQ with cisplatin and temozolomide resulted in synergistic inhibition of cell growth, producing long-term survivors of L1210 tumor-bearing mice. In conclusion, these results indicate that HEAMQ antineoplastic activity toward leukemia cells is associated with cell cycle arrest and apoptosis. The in vivo studies further confirmed the antitumor activity of HEAMQ and highlighted that this agent could be used to further increase therapeutic efficacies of traditional chemotherapeutic agents.

Betak E.,Slovak Academy of Sciences | Betak E.,Silesian University in Opava
Nuclear Data Sheets | Year: 2014

We address the angular momentum effects within the state density approach to the Iwamoto-Harada-(Bisplinghoff) model of the pre-equilibrium cluster emission. Using this way, the cluster emission is independent of the cluster formation probability, which - using a rough approximation - contains also all angular momenta couplings related to the creation of a cluster in nuclear reaction. Consequently, the angular-momentum part of the cluster emission rate is formally the same as it is in the nucleon emission case (but energy parts are substantially different). The 197Au(p,α) reaction at 62 MeV serves as an illustration of the suggested model. Inclusion of spin variables causes the enhancement of the α channel (and a weakening of the sum of nucleon channels due to particle emission competition) compared to the spin-independent case. © 2014.

Dubnicka S.,Slovak Academy of Sciences | Dubnickova A.Z.,Comenius University
Acta Physica Slovaca | Year: 2010

The utility of an application of the analyticity in a phenomenology of electro-weak structure of hadrons is demonstrated in a number of obtained new and experimentally verifiable results. With this aim first the problem of an inconsistency of the asymptotic behavior of VMD model with the asymptotic behavior of form factors of baryons and nuclei is solved generally and a general approach for determination of the lowest normal and anomalous singularities of form factors from the corresponding Feynman diagrams is reviewed. Then many useful applications by making use of the analytic properties of electro-weak form factors and amplitudes of various electromagnetic processes of hadrons are carried out.

Simkovic I.,Slovak Academy of Sciences
Carbohydrate Polymers | Year: 2013

Composites made solely from polysaccharides are mostly ecological because they can degrade without leaving behind ecologically harmful residues, in contrast to composites which contain synthetic polymers. Herein, the following groups of all-polysaccharide composites (APCs) are discussed: an all-cellulose group that includes cotton composites, cellulose combined with other polysaccharides, as well as those based on chitin/chitosan, heparin, hyaluronan, xylan, glucomannan, pectin, xyloglucan, arabinan, starch, carrageenan, alginate, galactan as one of the components in combination with other polysaccharides. They can be used in medical, paper, food, packing, textile, electronic, mechanical engineering and other applications. The composites were tested for absorptivity, biodegradability, crystallinity, rheology, and mechanical, optical, separation, gelling, pasting, film-forming, adhesive, antimicrobial properties, as well as water vapor permeability, water repellency, dye uptake, and fire-retardancy. Except for food applications, composites based on more than two types of polysaccharides have rarely been used and many possible combinations remain unexplored. © 2013 Elsevier Ltd. All rights reserved.

Plescha M.,Slovak Academy of Sciences | Pivoluska M.,Masaryk University
Physics Letters, Section A: General, Atomic and Solid State Physics | Year: 2014

Expansion and amplification of weak randomness with untrusted quantum devices has recently become a very fruitful topic of research. Here we contribute with a procedure for amplifying a single weak random source using tri-partite GHZ-type entangled states. If the quality of the source reaches a fixed threshold R = log2 (10), perfect random bits can be produced. This technique can be used to extract randomness from sources that can't be extracted neither classically, nor by existing procedures developed for Santha-Vazirani sources. Our protocol works with a single fault-free device decomposable into three non-communicating parts, that is repeatedly reused throughout the amplification process. © 2014 Elsevier B.V. All rights reserved.

Capkovic F.,Slovak Academy of Sciences
INES 2015 - IEEE 19th International Conference on Intelligent Engineering Systems, Proceedings | Year: 2015

During cooperation of several robots in a limited working space critical situations can occur. The main aim of this paper is to point out the possibility of utilizing the Petri net-based approach in order to eliminate them. In such a case usually only one robot is allowed to enter the working space. Place/transition Petri nets are used here to model the robotic cell and to synthesize supervisors ensuring the cooperation of its devices. Then, timed Petri nets (TPN) are used in order to acquire the performance evaluation of the whole cell. © 2015 IEEE.

Khodabakhshi F.,Sharif University of Technology | Simchi A.,Sharif University of Technology | Kokabi A.H.,Sharif University of Technology | Gerlich A.P.,University of Waterloo | Nosko M.,Slovak Academy of Sciences
Materials and Design | Year: 2014

Aluminum matrix nanocomposites were fabricated via friction stir processing of an Al-Mg alloy with pre-inserted TiO2 nanoparticles at different volume fractions of 3%, 5% and 6%. The nanocomposites were annealed at 300-500°C for 1-5h in air to study the effect of annealing on the microstructural changes and mechanical properties. Microstructural studies by scanning and transmission electron microscopy showed that new phases were formed during friction stir processing due to chemical reactions at the interface of TiO2 with the aluminum matrix alloy. Reactive annealing completed the solid-state reactions, which led to a significant improvement in the ductility of the nanocomposites (more than three times) without deteriorating their tensile strength and hardness. Evaluation of the grain structure revealed that the presence of TiO2 nanoparticles refined the grains during friction stir processing while the in situ formed nanoparticles hindered the grain growth upon the post-annealing treatment. Abnormal grain growth was observed after a prolonged annealing at 500°C. The highest strength and ductility were obtained for the nanocomposites annealed at 400°C for 3h. © 2014 Elsevier Ltd.

Capek I.,Slovak Academy of Sciences
Designed Monomers and Polymers | Year: 2012

The miniemulsion polymerizations (MiEPs) of butyl acrylate (BA) initiated by UV-light have been studied. The oil-soluble dibenzoyl peroxide was used as a photoinitiator. Furthermore, the effect of sodium montmorillonite on kinetics and BA miniemulsion stabilized by anionic sodium dodecylsulfate (SDS) and anionic cetyltrimethylammonium bromide (CTAB) was studied. The polymerization rate vs. conversion curve of the photoinduced MiEP of BA was described by two and four nonstationary rate intervals. Two rate intervals with one rate maximum was observed with CTAB and four nonstationary rate intervals with two rate maxima appeared with SDS. Variation of the rate of polymerization with conversion was discussed in terms of types of initiating radicals and the gel effect. © 2012 Taylor & Francis.

Hurai V.,Slovak Academy of Sciences
Chemical Geology | Year: 2010

Temperatures and pressures of heterogeneous carbo-aqueous fluids are usually derived from the isochore of the gaseous phase calculated using an equation of state for the anhydrous gas. Theoretical calculations with binary CH4-H2O and CO2-H2O systems have shown that this approach is justified only for trapping pT conditions far away from the critical curve, and for the partial homogenization of the gaseous phase to vapour. In contrast, partial homogenization to the liquid phase is significantly affected by volume effects associated with the reaction of the gas to hydrates, and/or with the phase transformation of the supercooled water to hexagonal ice. The curvature and slope of the two-phase isochoric trajectory of the water-containing gaseous inclusion deviate slightly from that of a homogeneous supercritical anhydrous gas with an equivalent density, thus contributing to the inaccuracy of the calculated trapping pressure. The calculated geologic pressure can be significantly overestimated in CO2-H2O inclusions with the partial homogenization of the carbonic phase in the presence of water, and in CH4-H2O inclusions trapped at temperatures lower than 270°C. All heterogeneous gas-aqueous fluids trapped close to their critical conditions yield erroneous results when interpreted in terms of an anhydrous supercritical gas. Special care must be exercised when calculating the "minimum trapping pressure" from the partial homogenization temperature of the gaseous phase in aqueous liquid-dominated fluid inclusions. In this special case, a triple partial homogenization at extremely varying temperatures can be observed in H2O-CO2 inclusions with 30-40vol.% of the gaseous phase at room temperature: a metastable partial homogenization in the presence of ice and clathrate below Te, stable partial homogenization in the presence of aqueous liquid and clathrate, and a second metastable partial homogenization in the presence of aqueous liquid alone. © 2010 Elsevier B.V.

Renco M.,Slovak Academy of Sciences | Sasanelli N.,Institute for Plant Protection | Kovacik P.,Slovak University of Agriculture
Helminthologia | Year: 2011

Summary: A pot experiment on potato was carried out to verify the nematicidal effect of four composts of different origin (C1: 70 % horse manure + 15 % sugar beet pomace + 5 % poultry manure + 10% grape pomace; C2: 100 % pig manure decomposed by juveniles of Musca domestica; C3: 100 % vermicompost from medical plants wastes; C4: 100% vermicompost from cattle manure) on the potato cyst nematodes G. rostochiensis (Ro1) and G. pallida (Pa2 and Pa3). Composts at different rates (1.0, 2.5 and 5.0 % w/w) were mixed with the nematode infested soils. Pots with unamended soils were used as control. Pots (4 l) were arranged in a glasshouse according to a randomized block design with four replications per each treatment. A significant reduction in number of cysts, eggs and juveniles/cyst and eggs and juveniles/g soil was observed in each compost in comparison to unamended soil. The suppressive nematode effect increased according to the compost NH 4 + content and compost rate. © 2011 © Versita Warsaw and Springer-Verlag Wien.

Monosik R.,Slovak University of Technology in Bratislava | Stredansky M.,Biorealis Ltd | Tkac J.,Slovak Academy of Sciences | Sturdik E.,Slovak University of Technology in Bratislava
Food Analytical Methods | Year: 2012

The importance of analyses of different parameters in food products and monitoring of a production process requires quick and reliable analytical methods and devices. For this purpose, biosensors can be a suitable option, whereas most of the current quality control techniques are time consuming, expensive, and unpractical. In this paper, we describe biosensors developed for analysis of different components present in food samples, namely, glucose, fructose, sucrose, lactose, lactic, malic, acetic, ascorbic, citric and amino acids, ethanol, glycerol, and triglyceride. Biosensors showed desirable sensitivity, selectivity, and response time required for various applications. They are often designed to avoid interference from components present in a complex sample to be analyzed. © 2011 Springer Science+Business Media, LLC.

Cuchta P.,University of P.J. Safarik | Miklisova D.,Slovak Academy of Sciences | Kovac L.,University of P.J. Safarik
European Journal of Soil Biology | Year: 2012

Soil Collembola communities were investigated in spruce forest stands of the High Tatra Mts that had been heavily damaged by a windstorm in November 2004. The study focused on the effect two different forest practices had on collembolan community distribution and structure in the three years after the windstorm. Three different treatments were selected for the study: intact forest stands (REF), clear-cut windthrown stands (EXT), and non-extracted windthrown stands (NEX), with each treatment having three study stands. From a total 6829 individuals, 65 species were identified. The highest Collembola abundance means were recorded in NEX stands, with the same parameter being lower in REF stands and the lowest in EXT stands. Although there was a significant increase in abundance over time observed in EXT stands, this increase in abundance over time was much higher in NEX stands. The ordination method used demonstrated a significant influence of both treatment and sampling date on the abundance of Collembola. The present study shows that clearing windthrown spruce forests following a catastrophic storm is less favourable for communities of soil collembolans and slow down the recovery process. © 2012 Elsevier Masson SAS.

Luptacik P.,University of P.J. Safarik | Miklisova D.,Slovak Academy of Sciences | Kovac L.,University of P.J. Safarik
European Journal of Soil Biology | Year: 2012

A small-scale field study was carried out in the floodplain area of the Ondava River in the East-Slovak Lowland, Slovakia. The study aims were to compare soil oribatid mite diversity at sites within agricultural land and to assess the role of different land components as potential diversity sources. An arable field was sampled weekly on 12 sampling occasions at five sites along a transect line from a drainage ditch with a willow tree belt (hedgerow at field margin) and across the field, which had a terrain depression without water outflow. A spring-time investigation period was chosen when the field depression and the drainage ditch would have been waterlogged. Oribatid abundances at the uncultivated willow hedgerow and the depression were significantly different, not only from the rest of field sites but also from each other. The euryvalent species Oppiella nova, Oppiella obsoleta and Tectocepheus velatus dominated in the arable soils beyond the depression. The community species spectrum at the bottom of the depression, which had considerably higher soil moisture was similar to other field sites but hygro- and halotolerant Oxyoppia europaea, Microppia minus prevailed in this community. Low competitive ability and wide tolerance to environmental changes is probably the reason for the distribution pattern of these species. In the hedgerow a different community was established, with the dominant species Dissorhina ornata, Ramusella insculpta and Hermaniella dolosa being abundant usually in forest and meadow habitats rich in organic matter. Distinct environmental conditions at this site (no cultivation, leaf litter layer on the soil surface) enabled a more diverse oribatid community to establish itself, which was comprised of more specialized (less tolerant) species. We observed a high turnover rate of accidental species in field sites and more stable communities in hedgerow and depression sites. The results document that even small landscape units may serve as important diversity sources (corridors) for restitution of local microarthropod communities in arable fields (α-diversity), provided that management practices avoid drastic changes leading to the disturbance and degradation of arable soils. © 2011 Elsevier Masson SAS.

Samaj L.,Slovak Academy of Sciences
Acta Physica Slovaca | Year: 2010

This is the second part of a three-volume introductory course about integrable systems of interacting bodies. The models of interest are quantum spin chains with nearest-neighbor interactions between spin operators, in particular Heisenberg spin- 1/2 models. The Ising model in a transverse field, expressible as a quadratic fermion form by using the Jordan-Wigner transformation, is the subject of Sect. 12. The derivation of the coordinate Bethe ansatz for the XXZ Heisenberg chain and the determination of its absolute ground state in various regions of the anisotropy parameter are presented in Sect. 13. The magnetic properties of the ground state are explained in Sect. 14. Sect. 15 concerns excited states and the zero-temperature thermodynamics of the XXZ model. The thermodynamics of the XXZ Heisenberg chain is derived on the basis of the string hypothesis in Sect. 16; the thermodynamic Bethe ansatz equations are analyzed in high-temperature and low-temperature limits. An alternative derivation of the thermodynamics without using strings, leading to a non-linear integral equation determining the free energy, is the subject of Sect. 17. A nontrivial application of the Quantum Inverse Scattering method to the fully anisotropic XYZ Heisenberg chain is described in Sect. 18. Sect. 19 deals with integrable cases of isotropic spin chains with an arbitrary spin.

The effect of microwave irradiation upon starch hydrolysis and simultaneous epimerization of the D-glucose to D-mannose obtained was investigated. An acidic aqueous solution of starch was treated with a catalytic amount of hexavalent molybdenum salt in microwave field and the composition of the reaction mixture was analyzed. Rapid starch hydrolysis and subsequent epimerization provided an equilibrium reaction mixture of D-glucose and D-mannose (2:1) without the formation of any undesirable by-products. The reduction of D-mannose with sodium borohydride yielded D-mannitol in very good yield. Microwave irradiation proved to be an efficient tool for the transformation of starch to mannose over an MoVI catalyst. This method has the advantages of environmental friendliness, easy operation, good yields and substantial reduction of reaction time. © 2011 Elsevier Ltd. All rights reserved.

Horakova L.,Slovak Academy of Sciences
Interdisciplinary Toxicology | Year: 2011

Flavonoids, natural phenolic compounds, are known as agents with strong antioxidant properties. In many diseases associated with oxidative/nitrosative stress and aging they provide multiple biological health benefits. Ca2+-ATPases belong to the main calcium regulating proteins involved in the balance of calcium homeostasis, which is impaired in oxidative/nitrosative stress and related diseases or aging. The mechanisms of Ca2+-ATPases dysfunction are discussed, focusing on cystein oxidation and tyrosine nitration. Flavonoids act not only as antioxidants but are also able to bind directly to Ca2+- ATPases, thus changing their conformation, which results in modulation of enzyme activity.Dysfunction of Ca2+-ATPases is summarized with respect to their posttranslational and conformational changes in diseases related to oxidative/nitrosative stress and aging. Ca2+- ATPases are discussed as a therapeutic tool and the possible role of flavonoids in this process is suggested. Copyright © 2011 Slovak Toxicology Society SETOX.

Ferrari C.,Science 37 | Buffagni E.,Science 37 | Bonnini E.,Science 37 | Bonnini E.,University of Parma | Korytar D.,Slovak Academy of Sciences
Journal of Applied Crystallography | Year: 2013

Diffraction profiles of curved Si and GaAs crystals obtained by a controlled damage process on one side of planar crystals have been investigated at X-ray energies E = 17, 59 and 120keV. At E = 17 and 59keV in the condition of slight curvature, that is when the diffracting plane bending over the extinction length is lower than the Darwin width, the Laue diffraction profiles with lattice planes parallel or inclined with respect to the curvature radius R show an enhancement of integrated intensity proportional to 1/R, much larger than in the corresponding perfect bent crystals. At E = 120keV, in the condition of strong curvature, the crystals behave as bent perfect crystals with integrated intensity corresponding to that of a mosaic crystal. These crystals are proposed as optical elements for focusing hard X-ray beams. © 2013 International Union of Crystallography Printed in Singapore - all rights reserved.

Mucka P.,Slovak Academy of Sciences
International Journal of Pavement Engineering | Year: 2015

Paper summarised the proposals of fourteen new alternative indexes intended for road roughness evaluation of longitudinal road profile, which have been introduced in the last decade approximately. The main advantages of proposed indexes are: (1) effort to reflect the most of ride quality aspects such as ride comfort, ride safety and dynamic load of road or cargo; (2) using the insitu measurements of vibration response or subjective perception of vibration; (3) effort to reflect the vehicle responses such as roll and pitch vibration, or longitudinal and lateral vibration; (4) effort to detect the critical parts of road in a spatial domain; and (5) effort to reflect a vehicle velocity. The main limitations of proposed indexes are: (1) many proposals are only alternative to the international roughness index (IRI) or are based on the IRI procedure; (2) a simple one-dimensional vehicle model is often used with the constant parameters and velocity; and (3) orientation to one vibration response category as ride comfort. © 2015 Taylor & Francis

Stefek M.,Slovak Academy of Sciences
Interdisciplinary Toxicology | Year: 2011

Cataract is one of the earliest secondary complications of diabetes mellitus. The lens is a closed system with limited capability to repair or regenerate itself. Current evidence supports the view that cataractogenesis is a multifactorial process. Mechanisms related to glucose toxicity, namely oxidative stress, processes of non-enzymatic glycation and enhanced polyol pathway significantly contribute to the development of eye lens opacity under conditions of diabetes. There is an urgent need for inexpensive, non-surgical approaches to the treatment of cataract. Recently, considerable attention has been devoted to the search for phytochemical therapeutics. Several pharmacological actions of natural flavonoids may operate in the prevention of cataract since flavonoids are capable of affecting multiple mechanisms or etiological factors responsible for the development of diabetic cataract. In the present paper, natural flavonoids are reviewed as potential agents that could reduce the risk of cataract formation via affecting multiple pathways pertinent to eye lens opacification. In addition, the bioavailability of flavonoids for the lens is considered. Copyright © 2011 Slovak Toxicology Society SETOX.

Orlicky O.,Slovak Academy of Sciences
Contributions to Geophysics and Geodesy | Year: 2010

The results of the magnetic measurements and mineralogic data of the submarine basalts and peridotites have been compared with the original model to explain the origin of the normal and the reversed remanent magnetization (RM) of volcanics. According to the author the Ti-rich titano-magnetite (Ti-Mt) bearing rocks (without the secondary magnetic phase) and the magnetite are always the carriers of only normal RM. The low-temperature oxidized Ti-Mt bearing rocks and those of the ilmenite-hematite bearing rocks of the deutheric oxidation origin (of the defined composition) are the carriers of dominantly reversed RM of the self-reversal origin. This idea have been approved by many results of submarine volcanics, mostly basalts.

Ostrozlik M.,Slovak Academy of Sciences
Contributions to Geophysics and Geodesy | Year: 2010

On the basis of the fifty three-year time series of air temperature and precipitation in three levels of the atmospheric layer the seasonal variability of air temperature and precipitation in the Low and High Tatras regions are studied. Measurements of the air temperature and precipitation at the meteorological observatories Lomnický štít, Skalnaté Pleso and Chopok during the 1955-2007 period were used to analyse the time series in winter season, and compared with the corresponding results from the normal period 1961-1990. By processing of the extensive experimental material many statistical characteristics of the precipitation in the Low and High Tatra Mts were obtained.

Klinovaja J.,University of Basel | Stano P.,RIKEN | Stano P.,Slovak Academy of Sciences | Loss D.,University of Basel | Loss D.,RIKEN
Physical Review Letters | Year: 2016

We consider periodically driven arrays of weakly coupled wires with conduction and valence bands of Rashba type and study the resulting Floquet states. This nonequilibrium system can be tuned into nontrivial phases such as topological insulators, Weyl semimetals, and dispersionless zero-energy edge mode regimes. In the presence of strong electron-electron interactions, we generalize these regimes to the fractional case, where elementary excitations have fractional charges e/m with m being an odd integer. © 2016 American Physical Society.

Mucka P.,Slovak Academy of Sciences
Komunikacie | Year: 2016

The paper examined the sensitivity of International Roughness Index (IRI) to the local discontinuities (various distresses, joints, joint and surface defects, other road features, etc.) of the cement concrete (CC) pavements. About 5 300 road records of total length 470 km from Long Term Pavement Performance (LTPP) program were processed. The raw profiles were separated into a random part and a distress part using the median filtering method. The median filter order was set to identify distresses of variable maximum width from 20 to 40 cm, and minimal height, 3 mm. About 26 000 distresses were separated and their dimensions were identified. The raw longitudinal road profiles were compared with the separated pure random parts. The mean relative increase in IRI caused by distresses was 3.3 % for maximum distress width 20 cm, 6.6 % (30 cm), and 10.7 % (40 cm).

Kruger D.H.,Institute of Medical Virology | Figueiredo L.T.M.,University of Sao Paulo | Song J.-W.,Korea University | Klempa B.,Institute of Medical Virology | Klempa B.,Slovak Academy of Sciences
Journal of Clinical Virology | Year: 2015

Hantaviruses are emerging zoonotic viruses which cause human disease in Africa, America, Asia, and Europe. This review summarizes the progress in hantavirus epidemiology and diagnostics during the previous decade. Moreover, we discuss the influence of ecological factors on the worldwide virus distribution and give an outlook on research perspectives for the next years. © 2014 Elsevier B.V.

Majtan T.,Aurora University | Majtan T.,Slovak Academy of Sciences | Kraus J.P.,Aurora University
Protein Expression and Purification | Year: 2012

Cystathionine β-synthase (CBS), a heme-containing pyridoxal-5- phosphate (PLP)-dependent enzyme, catalyzes the condensation of serine and homocysteine to yield cystathionine. Missense mutations in CBS, the most common cause of homocystinuria, often result in misfolded proteins. Arginine 266, where the pathogenic missense mutation R266K was identified, appears to be involved in the communication between heme and the PLP-containing catalytic center. Here, we assessed the effect of a short affinity tag (6xHis) compared to a bulky fusion partner (glutathione S-transferase - GST) on CBS wild type (WT) and R266K mutant enzyme properties. While WT CBS was successfully expressed either in conjunction with a GST or with a 6xHis tag, the mutant R266K CBS had no activity, did not form native tetramers and did not respond to chemical chaperone treatment when expressed with a GST fusion partner. Interestingly, expression of R266K CBS constructs with a 6xHis tag at either end yielded active enzymes. The purified, predominantly tetrameric, R266K CBS with a C-terminal 6xHis tag had ∼82% of the activity of a corresponding WT CBS construct. Results from thermal pre-treatment of the enzyme and the denaturation profile of R266K suggests a lower thermal stability of the mutant enzyme compared to WT, presumably due to a disturbed heme environment. © 2012 Elsevier Inc. All rights reserved.

Hajek M.,Masaryk University | Horsak M.,Masaryk University | Tichy L.,Masaryk University | Hajkova P.,Masaryk University | And 2 more authors.
Journal of Biogeography | Year: 2011

Aim The term relict refers to a formerly widespread species currently occurring in refugia that provide a persistent combination of specific ecological conditions. In peatlands, direct palaeoecological evidence of relict status exists for some plant species and, in the case of calcareous sediments, for some snail species. We tested whether some species are significantly linked to old calcareous fens at the millennial scale independent of the effect of recent fen area. We focused on three organism groups - vascular plants, bryophytes and land snails - that differ in the degree of preservation of their remains in calcareous fen sediments and in their dispersal ability. Location Western Carpathians (Slovakia and the Czech Republic). Methods The sample sites comprised 47 well-preserved calcareous fens, from which we compiled complete recent species lists, measured the area and analysed radiocarbon-dated samples from the deepest sediment and from the beginning of complete deforestation, as indicated by plant and snail fossils. Using the species co-occurrences in large data sets, we identified calcareous fen specialists and compared their recent distribution patterns against a null model that controlled for the effect of fen area. Results Two land snail species, eleven vascular plant species and no bryophyte species have statistically significant affinities with old fens, independent of the effect of recent fen area. For one bryophyte and one snail, the effects of age and area are not distinguishable. Main conclusions The results for land snails, being abundantly preserved and easily determinable in calcareous fen deposits, are in full accordance with the direct macrofossil evidence. This suggests that our approach indirectly revealed a relict distribution of the species. Identification of species that are significantly linked to ancient localities at the millennial scale has great potential in palaeoecology for the detection of stands with old sediments, and in nature conservation as a tool for the identification of long-term-persisting rare species that infrequently colonize young sites and thus deserve priority in the protection of their habitats. From a theoretical perspective, limited dispersal from old to new localities of the same habitat can contribute to spatial effects in biotic assemblages, even at relatively fine scales. © 2010 Blackwell Publishing Ltd.

A branched-chain aldose bearing an azido group at the C-2 position provides access to the corresponding 1-deoxy-1-azido- and 1-deoxy-1-amino ketoses in a single step via stereospecific isomerization. The isomerization exploited the catalytic effect of molybdate ions and microwave irradiation. The structures of the products were analyzed by NMR spectroscopy, IR, HRMS spectrometry and quantum-chemical DFT calculations. DFT-computed proton-proton coupling constants of the prepared Amadori ketose 1-deoxy-1-amino-d-gluco-heptulose were found to be comparable with the experimentally obtained coupling constants and were in agreement with the 4C1 pyranose form in aqueous solution at room temperature. © 2010 Elsevier Ltd. All rights reserved.

Halada L.,Slovak Academy of Sciences | Evans D.,French Natural History Museum | Romao C.,European Environment Agency | Petersen J.-E.,European Environment Agency
Biodiversity and Conservation | Year: 2011

The aim of this paper is to identify the habitat types listed in the Habitats Directive Annex I that require low-intensity agricultural management for their existence. We assessed the link between the Annex I habitat types and agricultural practices in order to identify habitat types that depend on the continuation of agricultural practices or whose existence is prolonged or spatially enlarged via blocking or reducing the secondary succession by agricultural activities. 63 habitat types that depend on or which can profit from agricultural activities-mainly grazing and mowing-were identified. They are classified into 2 groups: (1) habitats fully dependent on the continuation of agricultural management; (2) habitats partly dependent on the continuation of agricultural management. This paper also briefly discusses habitat types for which either doubts remain on their dependence on agricultural management, or the relation to extensive farming practices exists only in part of their area of distribution in Europe or under certain site conditions, respectively. Assessments of the conservation status of habitats of European Importance by 25 EU Member States in 2007 showed that habitats identified by us as depending on agricultural practices had a worse status than non-agricultural habitats. © 2011 Springer Science+Business Media B.V.

Vrsansky P.,Slovak Academy of Sciences | Vrsansky P.,Russian Academy of Sciences
Zootaxa | Year: 2010

Macroscopic fossils of terrestrial animals originating directly from deposits close to the Permian/Triassic boundary are very scarce. Volcanic ash sediments in Eastern Siberia were found to hold the cockroach Sobytie tungusicum gen. et sp. n. This new taxon belongs to the predominantly Palaeozoic family Phyloblattidae, but has many advanced features characteristic of the Mesozoic family Caloblattinidae, and also of the basal Liberiblattinidae. These connections provide an indication of the origin of the family Liberiblattinidae and thus all the Mesozoic cockroach lineages from such Phyloblattidae - precursors of the Caloblattinidae. Copyright © 2010 Magnolia Press.

Green R.M.,University of Colorado at Boulder | Saniga M.,Slovak Academy of Sciences
International Journal of Geometric Methods in Modern Physics | Year: 2013

We give a detailed description of the Veldkamp space of the smallest slim dense near hexagon. This space is isomorphic to PG(7,2) and its 28 - 1 = 255 Veldkamp points (that is, geometric hyperplanes of the near hexagon) fall into five distinct classes, each of which is uniquely characterized by the number of points/lines as well as by a sequence of the cardinalities of points of given orders and/or that of (grid-)quads of given types. For each type we also give its weight, stabilizer group within the full automorphism group of the near hexagon and the total number of copies. The totality of (255 choose 2)/3 = 10,795 Veldkamp lines split into 41 different types. We give a complete classification of them in terms of the properties of their cores (i.e. subconfigurations of points and lines common to all the three hyperplanes comprising a given Veldkamp line) and the types of the hyperplanes they are composed of. These findings may lend themselves into important physical applications, especially in view of recent emergence of a variety of closely related finite geometrical concepts linking quantum information with black holes. © 2013 World Scientific Publishing Company.

Strecka J.,University of P.J. Safarik | Cencarikova H.,Slovak Academy of Sciences | Lyra M.L.,Federal University of Alagoas
Physics Letters, Section A: General, Atomic and Solid State Physics | Year: 2015

Phase diagrams and thermodynamic properties of a correlated spin-electron system considering localized Ising spins on nodal sites and mobile electrons on decorating sites of doubly decorated planar lattices are rigorously examined with the help of generalized decoration-iteration transformation. The investigated model defined on loose-packed (honeycomb and square) lattices exhibits the phase diagram including a spontaneous ferromagnetic and antiferromagnetic order in a vicinity of quarter and half-filling, respectively, while the same model on close-packed (triangular and kagome) lattices only shows a spontaneous ferromagnetic order due to a kinetically-driven spin frustration at high electron concentrations. The lower critical concentration, at which the ferromagnetic order appears, is remarkably close to a bond percolation threshold in spite of the annealed character of the developed procedure. The specific heat exhibits at the critical temperature either a logarithmic divergence for integer-valued electron concentrations or it shows a finite-cusp for any non-integer electron concentration due to the annealed bond disorder. © 2015 Elsevier B.V.

Williams A.M.,University of Surrey | Balaz V.,Slovak Academy of Sciences
Journal of Risk Research | Year: 2014

Migration is a risky behaviour because of the uncertainty about future wages, living conditions, changing relationships with family and friends and cultural adjustment. While there has been some research on risk and uncertainty in migration, this has mostly been approached as a form of rational decision-making: such approaches explain why some groups of individuals are more likely than others to migrate, but are limited in explaining individual variations in behaviour within these groups. Individual migrants vs. non-migrants are self-selected in terms of tolerance of risk and uncertainty but, with very few exceptions, there has been no research on migration within the framework of risk tolerance/aversion and competence to manage risk. Moreover, existing research is based on, and constrained by the limitations of, incumbent data-sets. Drawing on a specially commissioned large-scale survey of the UK population, this paper uses principal component analysis and logistic regression to analyse the extent to which risk and risk-related measures can be used to predict four different types of mobility profiles. There are significant associations between these individual mobility characteristics and general risk/uncertainty tolerance, and competence-based tolerance. These are strongest in terms of the two most polarised mobility types: the least mobile, the Stayers, and the most mobile, the Roamers. Recognising that previous migration is exogenous, a further analysis of migration intentions, with previous migration included as an independent variable, finds the propensity for future migration is, in fact, negatively associated with previous migration, probably due to the importance of pure risk as opposed to acquired competence via migration experience, and to life cycle considerations. © 2013 Taylor and Francis.

Plavalova E.,Slovak Academy of Sciences
Contributions of the Astronomical Observatory Skalnate Pleso | Year: 2014

While working with extra-solar planet databases, it is very useful to have a taxonomy scale (classification), for example, like the Harvard classification for stars. This new taxonomy has to be comprehensible and present the most relevant information about extra-solar planets. We propose an extra-solar planet taxonomy scale with five parameters.

Tomko D.,Slovak Academy of Sciences
Contributions of the Astronomical Observatory Skalnate Pleso | Year: 2014

We deal with a theoretical meteoroid stream of the comet 122P/de Vico. For five perihelion passages in the distant past, we model a theoretical stream and follow its dynamical evolution until the present. We predict the characteristics of potential a meteor shower approaching the Earth's orbit and we make also the identification of the particles of the predicted shower with the real meteors in three databases (photo, radar, and video). Our overall prediction is, however, negative because only the particles released from the comet nucleus before approximately 37 000 years are found to evolve into a collision course with the Earth and, therefore, form a possible shower. Many meteoroids do not survive such a long time in interplanetary space.

Foulis D.J.,University of Massachusetts Amherst | Pulmannova S.,Slovak Academy of Sciences
Reports on Mathematical Physics | Year: 2011

Elements of the exocenter of a generalized effect algebra (GEA) correspond to decompositions of the GEA as a direct sum and thus the exocenter is a generalization to GEAs of the center of an effect algebra. The exocenter of a GEA is shown to be a boolean algebra, and the notion of a hull mapping for an effect algebra is generalized to a hull system for a GEA. We study Dedekind orthocompleteness of GEAs and extend to GEAs the notion of a centrally orthocomplete effect algebra. © 2011 Polish Scientific Publishers.

Racko D.,Slovak Academy of Sciences
Acta Physica Polonica A | Year: 2014

In this contribution the free volume of glycerol phase confined in a nanopore in a wide temperature range is computed. The computed free volume is compared to the previously computed values in the glycerol bulk. The mean cavity volumes are also discussed with the experimental measurements by positronium annihilation lifetime spectroscopy. The computer simulations show that in the case of the confined glycerol phase the mean cavity volumes are larger than in the simulated bulk, and also the temperature dependence has a different qualitative behavior; the computed data are in agreement with experimental measurements performed for glycerol in a pore of comparable size with diameter 6 nm. The simulations also indicate that an aspect of filling a pore is important for experimentalists. In the case of a perfectly sealed pore the cavity volume is observed to rise with decreasing temperature.

Skopal A.,Slovak Academy of Sciences
Contributions of the Astronomical Observatory Skalnate Pleso | Year: 2014

Symbiotic stars comprise a cool giant and a white dwarf (WD) on, typically, a few years orbit. The white dwarf accretes from the giant's wind, heats up to 1-2 × 105 K, ionizes the circumbinary environment, and is subject to occasional outbursts. The presence of physically different sources of radiation and particles in the system, diversing extremely in temperatures, produces a complex composite spectrum from X-rays to radio wavelengths. In my presentation I will introduce some main points of the research of symbiotic stars based on the multicolour photometry carried out by small telescopes of the Astronomical Institute of the Slovak Academy of Sciences.

Kalinay P.,Slovak Academy of Sciences | Percus J.K.,Courant Institute of Mathematical Sciences | Percus J.K.,New York University
Physical Review E - Statistical, Nonlinear, and Soft Matter Physics | Year: 2011

We study diffusion of pointlike particles biased toward the x axis by a quadratic potential U(x,y)=κ(x)y2. This system mimics a channel with soft walls of some varying (effective) cross section A(x), depending on the stiffness κ(x). We show that diffusion in this geometry can also be mapped rigorously onto the longitudinal coordinate x by a procedure known for channels with hard walls; i.e., we arrive at a one-dimensional evolution equation of the Fick-Jacobs type. On the other hand, the calculation presented serves as a prototype for mapping of the Smoluchowski equation with a wide class of potentials U(x,y) varying in both the longitudinal as well as the transverse directions, which is necessary for understanding, e.g., stochastic resonance. © 2011 American Physical Society.

Husarik M.,Slovak Academy of Sciences
Contributions of the Astronomical Observatory Skalnate Pleso | Year: 2014

Despite very valuable information from space missions (NEAR, Hayabusa,.) extremely important data about asteroids are provided by pho-tometric observations from ground-based telescopes. Because observations are so time-consuming, small telescopes (< 2 m) at professional observatories are mostly used. The community of amateur astronomers also perform extraordi-nary precise work using even smaller telescopes (> 0:2 m). The results of short-term photometry are the rotational period and the am-plitude of changes of brightness in a variety of solar phase angles. Medium-term photometry is able to cover eclipses/occultations of binary asteroids very well and to determine the parameters of the primary and the satellite. Long-term photometry detects amplitude variations in different apparitions, determines the direction of rotation axes and the sense of rotation and helps to create a 3D model of the asteroid's shape. By using photometric data from a wider time interval we can study the thermal YORP effect, which affects the trajectory and rotation of asteroids (mainly NEAs). It can be used also in the photometric survey of the paired asteroids.

Holic R.,Japan National Institute of Advanced Industrial Science and Technology | Holic R.,Slovak Academy of Sciences | Yazawa H.,Japan National Institute of Advanced Industrial Science and Technology | Kumagai H.,Asahi Glass Co. | Uemura H.,Japan National Institute of Advanced Industrial Science and Technology
Applied Microbiology and Biotechnology | Year: 2012

In an effort to produce ricinoleic acid (12-hydroxy-octadeca-cis-9-enoic acid: C18:1-OH) as a petrochemical replacement in a variety of industrial processes, we introduced Claviceps purpurea oleate Δ12-hydroxylase gene (CpFAH12) to Schizosaccharomyces pombe, putting it under the control of inducible nmt1 promoter. Since Fah12p is able to convert oleic acid to ricinoleic acid, we thought that S. pombe, in which around 75% of total fatty acid (FA) is oleic acid, would accordingly be an ideal microorganism for high production of ricinoleic acid. Unfortunately, at the normal growth temperature of 30°C, S. pombe cells harboring CpFAH12 grew poorly when the CpFAH12 gene expression was induced, perhaps implicating ricinoleic acid as toxic in S. pombe. However, in line with a likely thermoinstability of Fah12p, there was almost no growth inhibition at 37°C or, by contrast with 30°C and lower temperatures, ricinoleic acid accumulation. Accordingly, various optimization steps led to a regime with preliminary growth at 37°C followed by a 5-day incubation at 20°C, and the level of ricinoleic acid reached 137.4 μg/ml of culture that corresponded to 52.6% of total FA. © 2012 Springer-Verlag.

Reiterova K.,Slovak Academy of Sciences | Auer H.,Medical University of Vienna | Altintas N.,Ege University | Yolasigmaz A.,Ege University
Parasitology Research | Year: 2014

Echinococcus granulosus antigen B fraction (AgB) was evaluated for its prognostic value in the serological follow-up of cystic echinococcosis (CE), compared to crude hydatid fluid (HF) as well as soluble somatic Echinococcus multilocularis antigen (Em). The sensitivity and specificity of enzyme-linked immunosorbent assays (ELISA) were compared examining 177 sera from patients with different clinical courses and outcome of CE and with other parasitic infections. AgB-ELISA in comparison to confirmed cystic echinococcosis has 96.4 % sensitivity and 97.2 % specificity, with 93.1 % positive predictive value and 98.6 % negative predictive value. The HF-ELISA was more sensitive than the AgB-ELISA, but its specificity was lower. Our results indicate that AgB-ELISA was more satisfactory for seroconfirmation of acute echinococcosis than HF-ELISA. Moreover, the AgB-ELISA has a potential key role in control measures implemented in patients undergoing surgery. In sera of patients more than 3 months after the treatment, no antibody response to antigen B was detected; however, with conventionally used HF-ELISA, they were still positive. The AgB is recommended for the confirmatory diagnosis. AgB-WB allocated low background with typical "triplet" bands at 8-12-16 kDa. © 2014 Springer-Verlag.

Ladislav H.,Slovak Academy of Sciences
Journal of Hydrology and Hydromechanics | Year: 2010

Open area rainfall and throughfall measurements in the Western Tatra Mountains (altitude about 1500 m a.s.l.) made by tipping bucket gauges were used to estimate the usefulness of the short-time data in analysis of spruce interception. The 10-minute data from period 13 May-13 October 2009 did not reveal meaningful correlations between the open area rainfall and throughfall. Aggregated measurements representing individual rainfall events were more useful. They showed linear relationship between open area rainfall and throughfall for events with total rainfall depth in the open area exceeding 5 mm. Correlation between open area rainfall and throughfall for rainfall events with duration above 120 minutes was significantly better than for the shorter ones. Mean values of interception (percentage of open area rainfall which did not appear in throughfall) of individual rainfall events was high. When we excluded events for which throughfall was higher than the open area rainfall, mean interception for larger and longer rainfall events was 46% and 48%, respectively. For smaller (runoff depth below 5 mm) and shorter events (duration below 2 hours) the mean interception was 70% and 72%, respectively. However, the data revealed very high variability of interception.

Orosova M.,Slovak Academy of Sciences | Orosova M.,Academy of Sciences of the Czech Republic | Oros M.,Academy of Sciences of the Czech Republic
Parasitology Research | Year: 2012

Chromosomes of the invasive tapeworm Khawia sinensis (Caryophyllidea), the specific parasite of common carp, were analyzed by means of conventional Giemsa staining and using fluorescent DAPI and YOYO-1 dyes, silver staining, and fluorescent in situ hybridization (FISH) with 18S rDNA probe. The karyotype is composed of eight pairs of metacentric and telocentric chromosomes (2n016, n=3m+5t, TCL=42.54 μm). Constitutive heterochromatin was located at pericentromeric regions of all pairs, except for the largest metacentric pair (no. 1), which possessed no DAPI-positive band. FISH with rDNA probe revealed that both homologues of chromosome pair no. 6 carry a cluster of ribosomal arrays, which were located interstitially close to the centromere. Present results are compared with previous cytogenetic data on Khawia spp., and comments are made on the karyotypes with respect to their phylogenetic links. © Springer-Verlag 2011.

Narasaki C.T.,Texas A&M University | Toman R.,Slovak Academy of Sciences
Advances in Experimental Medicine and Biology | Year: 2012

A lipopolysaccharide (LPS) is considered to be one of the major determinants of virulence expression and infection of virulent Coxiella burnetii. The LPSs from virulent phase I (LPS I) and from avirulent phase II (LPS II) bacteria were investigated for their chemical composition, structure and biological properties. LPS II is of rough (R) type in contrast to LPS I, which is phenotypically smooth (S) and contains a noticeable amount of two sugars virenose (Vir) and dihydrohydroxystreptose (Strep), which have not been found in other LPSs and can be considered as unique biomarkers of the bacterium. Both sugars were suggested to be located mostly in terminal positions of the O-specific chain of LPS I (O-PS I) and to be involved in the immunobiology of Q fever. There is a need to establish a more detailed chemical structure of LPS I in connection with prospective, deeper studies on mechanisms of pathogenesis and immunity of Q fever, its early and reliable diagnosis, and effective prophylaxis against the disease. This will also help to better understanding of host-pathogen interactions and contribute to improved modulation of pathological reactions which in turn are prerequisite for research and development of vaccines of new type. A fundamental understanding of C. burnetii LPS biosynthesis is still lacking. The intracellular nature of the bacterium, lack of genetic tools and its status as a selected agent have made elucidating basic physiological mechanisms challenging. The GDP-β-D-Vir biosynthetic pathway proposed most recently is an important initial step in this endeavour. The current advanced technologies providing the genetic tools necessary to screen C. burnetii mutants and propagate isogenic mutants might speed the discovery process. © 2012 Springer Science+Business Media Dordrecht.

Veselsky M.,Slovak Academy of Sciences | Ma Y.G.,CAS Shanghai Institute of Applied Physics
Physical Review C - Nuclear Physics | Year: 2013

The extension of the Boltzmann-Uehling-Uhlenbeck model of nucleus-nucleus collision is presented. The isospin-dependent nucleon-nucleon cross sections are estimated using the proper volume extracted from the equation of state of the nuclear matter transformed into the form of the Van der Waals equation of state. The results of such simulations demonstrate the dependence on symmetry energy, which typically varies strongly from the results obtained using only the isospin-dependent mean field. The evolution of the n/p multiplicity ratio with angle and kinetic energy, in combination with the elliptic flow of neutrons and protons, provides a suitable set of observables for determination of the density dependence of the symmetry energy. The model thus provides an environment for testing of equations of state that are used for various applications in nuclear physics and astrophysics. © 2013 American Physical Society.

Ceniga L.,Slovak Academy of Sciences
Mechanics Research Communications | Year: 2015

This paper represents a continuation of the author's previous work which deals with an analytical model of thermal stresses which originate during a cooling process of an anisotropic solid elastic continuum. This continuum consists of anisotropic spherical particles which are periodically distributed in an anisotropic infinite matrix. The infinite matrix is imaginarily divided into identical cubic cells with central particles. This multi-particle-matrix system represents a model system which is applicable to two-component materials of the precipitate-matrix type. The thermal stresses, which originate due to different thermal expansion coefficients of components of the model system, are determined within the cubic cell. The analytical modelling results from fundamental equations of continuum mechanics for solid elastic continuum (Cauchy's, compatibility and equilibrium equations, Hooke's law). This paper presents suitable mathematical procedures which are applied to the fundamental equations. These mathematical procedures lead to such final formulae for the thermal stresses which are relatively simple in comparison with the final formulae presented in the author's previous work which are extremely extensive. Using these new final formulae, the numerical determination of the thermal stresses in real two-component materials with anisotropic components is not time-consuming. © 2015 Elsevier Ltd. All rights reserved.

Svoren J.,Slovak Academy of Sciences
Contributions of the Astronomical Observatory Skalnate Pleso | Year: 2014

The paper presents the results of CCD astrometry of comets carried out at the Skalnaté Pleso Observatory in 2003. A total of 233 observations of 21 comets are given.

Majernik V.,Slovak Academy of Sciences
Gravitation and Cosmology | Year: 2014

We consider a two-component universe consisting of ordinary matter and vacuum energy quantitatively described by the cosmological term Lc = (l/a)ρc, where l is a quantity having the dimension of length, ρc is the density of ordinary matter, and a is the scale factor. To justify the form of Lc, we use the Maxwell-like approach to gravitation in which it is supposed that the gravitational field energy gravitates. The total energy conservation law for both cosmic components determines the mass density and the vacuum energy density as a function of the scale factor. Applying this two-component cosmic model to the present universe, the important cosmic parameters get values consistent with observations. The ratio of density parameters of ordinary matter and vacuum mass-energy, Ωm/Ωl, in today’s universe is 1/2. Interesting features of our model are (i) the existence of an inflationary phase just at the earliest era of the universe follows directly from the modified Friedmann equations, and (ii) the beginning of cosmic expansion, the Big-Bang, is singularity-free, i.e., both the mass and vacuum energy contents assume finite values at the very origin of the universe. © 2014, Pleiades Publishing, Ltd.

Filip P.,Slovak Academy of Sciences
Physics of Particles and Nuclei | Year: 2014

The response of pseudoscalar and vector mesons to strong magnetic fields is studied within a simple constituent quark model using analogy with bound states of Positronium. Magnetic moments of charged vector mesons K*, D*, B* are predicted and it is found that η mesons have magnetic polarizability. In extremely strong magnetic fields, behaviour of J/Ψ mesons is discussed. We speculate on the existence of an induced magnetic moment of η meson. © 2014 Pleiades Publishing, Ltd.

Statistical analysis of facies clustering in deep-water successions in combination with their facies characteristics has been applied to interpretation of the depositional sub-environment of two selected sedimentary sequences, which expose the Upper Eocene Kýčera Member of the Zlín Formation of the Rača Unit and the Middle Eocene-Lower Oligocene Racibor Formation of the Krynica (Oravská Magura) Unit of the Magura Zone of the Outer Western Carpathians. Clustering patterns of three bed-by-bed variables, namely coarse division thickness, coarse division thickness percentages, and basal grain size were analyzed. Apart from coarse division thickness percentages of the Kýčera Member section, all the datasets passed the Hurst K test and, according to their facies characteristics, revealed the lobe-interlobe motif. Although the employment of this technique confirmed the advantages of its practical utilization in interpretation of submarine fan environments, its widespread application is limited to good exposures where adequate quantity and quality of data is available. © 2012 Springer-Verlag.

Lattova E.,University of Manitoba | Lattova E.,Slovak Academy of Sciences | Perreault H.,University of Manitoba
Mass Spectrometry Reviews | Year: 2013

Over the last years, extensive studies have evaluated glycans from different biological samples and validated the importance of glycosylation as one of the most important post-translational modifications of proteins. Although a number of new methods for carbohydrate analysis have been published and there has been significant progress in their identification, the development of new approaches to study these biomolecules and understand their role in living systems are still vivid challenges that intrigue glycobiologists. In the last decade, the success in analyses of oligosaccharides has been driven mainly by the development of innovative, highly sensitive mass spectrometry techniques. For enhanced mass spectrometry detection, carbohydrate molecules are often derivatized. Besides, the type of labeling can influence the fragmentation pattern and make the structural analysis less complicated. In this regard, in 2003 we introduced the low scale, simple non-reductive tagging of glycans employing phenylhydrazine (PHN) as the derivatizing reagent. PHN-labeled glycans showed increased detection and as reported previously they can be analyzed by HPLC, ESI, or MALDI immediately after derivatization. Under tandem mass spectrometry conditions, PHN-derivatives produced useful data for the structural elucidation of oligosaccharides. This approach of analysis has helped to reveal new isomeric structures for glycans of known/unknown composition and has been successfully applied for the profiling of N-glycans obtained from serum samples and cancer cells. The efficacy of this labeling has also been evaluated for different substituted hydrazine reagents. This review summarizes all types of reducing-end labeling based on hydrazone-linkage that have been used for mass spectrometric analyses of oligosaccharides. This review is also aimed at correcting some past misconceptions or interpretations reported in the literature. © 2013 Wiley Periodicals, Inc. Rapid Commun. Mass Spectrom. 32: 366-385, 2013. © 2013 Wiley Periodicals, Inc.

Bucko T.,Comenius University | Bucko T.,Slovak Academy of Sciences | Hafner J.,University of Vienna | Lebegue S.,University of Lorraine | Angyan J.G.,University of Lorraine
Physical Chemistry Chemical Physics | Year: 2012

Periodic dispersion corrected DFT calculations have been performed to study the spin-crossover transition of Fe(phen)2(NCS)2 in the molecular and in the crystalline state. We show that London dispersion interactions play a crucial role in the cohesion of the crystals. Based on calculations of vibrational eigenstates of the isolated molecule and of the crystalline phase in both the low- and high-spin states, the transition entropies and enthalpies have been calculated. We demonstrate that, due to the stabilization of the low-spin state by intermolecular dispersion forces, the transition enthalpy at the transition temperature is larger for the crystalline phase in comparison with an isolated molecule. The effective coordination number of the nitrogen atoms of the ligands around the iron atom has been identified as the order parameter driving the quasi-reversible low-spin to high-spin transition in the crystal. Finally, using constrained geometry relaxations at fixed values of the coordination number, we computed the energy barrier of the LS to HS transition and found it to be in a reasonable agreement with the experimental value. © the Owner Societies 2012.

Kocifaj M.,Slovak Academy of Sciences
Astrophysics and Space Science | Year: 2012

The two-stream concept is used for modeling the radiative transfer in Earth's atmosphere illuminated by ground-based light sources. The light pollution levels (illuminance and irradiance) are computed for various aerosol microphysical parameters, specifically the asymmetry parameter g A, single scattering albedo ω A, and optical thickness τ A. Two distinct size distributions of Junge's and gamma-type are employed. Rather then being a monotonic function of τ A, the diffuse illuminance/irradiance shows a local minimum at specific τ A,lim independent of size distribution taken into consideration. The existence of local minima has relation to the scattering and attenuation efficiencies both of which have opposite effects. The computational scheme introduced in this paper is advantageous especially if the entire set of calculations needs to be repeated with an aim to simulate diffuse light in various situations and when altering optical states of the atmospheric environment. © 2012 Springer Science+Business Media B.V.

Simkovic I.,Slovak Academy of Sciences
Carbohydrate Polymers | Year: 2012

Unbleached cotton fabrics (UCF) with 12.5% polypropylene scrim treated with two phosphate-urea based fire-retardant (FR) formulations were evaluated for FR properties using thermogravimetry/differential thermogravimetry/differential thermal analysis (TG/DTG/DTA) method. In addition to testing the two FR-treated unbleached cotton fabrics (CF-FR1 and CF-FR2), bleached cotton fabric (BCF) treated with the two FR formulations (BCF-FR1 and BCF-FR2) was evaluated. Both formulations were washable with add-on of FR chemicals at 18.7% (FR1) or 17.4% (FR2) for UCF and 22.5% (FR1) or 24.9% (FR2) for BCF. The decreasing order of sums at maximal rates of samples degradation in air environment according to DTG method was: BCF (21.40%/min) > UCF (12.91%/min) > BCF-FR2 (12.83%/min) > BCF-FR1 (11.68%/min) > CF-FR2 (10.20%/min) > CF-FR1 (9.73%/min). It indicates that both formulations cause the decrease of thermooxidation of the products at slower rates than the starting material. Several endo- and exothermic peaks observed by DTA in inert and oxidative environment gives additional information about the degradation process. The order of decreasing thermal responses of the studied samples based on sums of DTA peak values of endothermic and exothermic peaks in air environment is: UCF (0.597 °C/mg) > BCF (0.120 °C/mg) > CF-FR1 (0.089 °C/mg) > BCF-FR1 (0.077 °C/mg) > CF-FR2 (0.062 °C/mg) > BCF-FR2 (0.053 °C/mg). This is in agreement with the cone calorimeter results according to which the flammability properties are improving with the decreasing heat release rates or ignition time prolongation in order: UCF > CF-FR1 > CF-FR2. The advantage of TG/DTG/DTA method is slower linear heating rate, which allows the more detailed evaluation of the light and flammable cotton fabric. © 2012 Elsevier Ltd. All rights reserved.

Varga S.,Slovak Academy of Sciences
Journal of Mathematical Chemistry | Year: 2011

Two theorems for robust density fitting are proved: A. For a given electron density, the best robust density fitting approximation to the Coulomb electron repulsion energy results from the unconstrained Coulomb metric fit, B. For infinite periodic systems, the necessary condition for correct long-range behavior of any robust density fitting approximation of the Coulomb electron repulsion energy is the exact reproduction of the number of electrons. © 2010 Springer Science+Business Media, LLC.

Gabrisko M.,Slovak Academy of Sciences
Journal of Molecular Evolution | Year: 2013

Although some α-glucosidases from the α-amylase family (glycoside hydrolase family GH13) have been studied extensively, their exact number, organization on the chromosome, and orthology/paralogy relationship were unknown. This was true even for important disease vectors where gut α-glucosidase is known to be receptor for the Bin toxin used to control the population of some mosquito species. In some cases orthologs from related species were studied intensively, while potentially important paralogs were omitted. We have, therefore, used a bioinformatics approach to identify all family GH13 α-glucosidases from the selected species from Metazoa (including three mosquito species: Aedes aegypti, Anopheles gambiae, and Culex quinquefasciatus) as well as from Fungi in an effort to characterize their arrangement on the chromosome and evolutionary relationships among orthologs and among paralogs. We also searched for pseudogenes and genes coding for enzymatically inactive proteins with a possible new function. We have found GH13 α-glucosidases mostly in Arthropoda and Fungi where they form gene families, as a result of multiple lineage-specific gene duplications. In mosquito species we have identified 14 α-glucosidase (Aglu) genes of which only five have been biochemically characterized so far, two are putative pseudogenes and the rest remains uncharacterized. We also revealed quite a complex evolutionary history of the eukaryotic α-glucosidases probably involving multiple losses of genes or horizontal gene transfer from bacteria. © 2013 Springer Science+Business Media New York.

Chiang C.-F.,University of Central Florida | Nagaj D.,Slovak Academy of Sciences | Wocjan P.,University of Central Florida
Quantum Information and Computation | Year: 2010

We present an efficient general method for realizing a quantum walk operator corresponding to an arbitrary sparse classical random walk. Our approach is based on Grover and Rudolph's method for preparing coherent versions of efficiently integrable probability distributions [1]. This method is intended for use in quantum walk algorithms with polynomial speedups, whose complexity is usually measured in terms of how many times we have to apply a step of a quantum walk [2], compared to the number of necessary classical Markov chain steps. We consider a finer notion of complexity including the number of elementary gates it takes to implement each step of the quantum walk with some desired accuracy. The difference in complexity for various implementation approaches is that our method scales linearly in the sparsity parameter and poly-logarithmically with the inverse of the desired precision. The best previously known general methods either scale quadratically in the sparsity parameter, or polynomially in the inverse precision. Our approach is especially relevant for implementing quantum walks corresponding to classical random walks like those used in the classical algorithms for approximating permanents [3, 4] and sampling from binary contingency tables [5]. In those algorithms, the sparsity parameter grows with the problem size, while maintaining high precision is required. © Rinton Press.

Kalinay P.,Slovak Academy of Sciences
Journal of Chemical Physics | Year: 2013

Applicability of the effective one-dimensional equations, such as Fick-Jacobs equation and its extensions, describing diffusion of particles in 2D or 3D channels with varying cross section A(x) along the longitudinal coordinate x, is studied. The leading nonstationary correction to Zwanzig-Reguera-Rubí equation [R. Zwanzig, J. Phys. Chem. 96, 3926 (1992)10.1021/j100189a004; D. Reguera and J. M. Rubí, Phys. Rev. E 64, 061106 (2001)10.1103/PhysRevE.64.061106] is derived and tested on the exactly solvable model, diffusion in a 2D linear cone. The effects of such correction are demonstrated and discussed on elementary nonstationary processes, a time dependent perturbation of the stationary flow and calculation of the mean first passage time. © 2013 AIP Publishing LLC.

Krajci M.,Slovak Academy of Sciences | Hafner J.,University of Vienna
Journal of Chemical Physics | Year: 2013

The polar threefold surfaces of the GaPd compound crystallizing in the B20 (FeSi-type) structure (space group P213) have been investigated using density-functional methods. Because of the lack of inversion symmetry the B20 structure exists in two enantiomorphic forms denoted as A and B. The threefold {111} surfaces have polar character. In both nonequivalent (111) and (111) directions several surface terminations differing in structure and chemical composition are possible. The formation of the threefold surfaces has been studied by simulated cleavage experiments and by calculations of the surface energies. Because of the polar character of the threefold surfaces calculations for stoichiometric slabs permit only the determination of the average energy of the surfaces exposed on both sides of the slab. Calculations for nonstoichiometric slabs performed in the grand canonical ensemble yield differences of the surface energies for the possible terminations as a function of the chemical potential in the reactive atmosphere above the surface and predict a transition between Ga- and Pd-terminated surfaces as a function of the chemical potential. The {100} surfaces are stoichiometric and uniquely defined. The calculated surface energies are identical to the average energies of the {100} surfaces of the pure metals. The {210} surfaces are also stoichiometric, with an energy very close to that of the {100} surfaces. Assuming that for the {111} surfaces the energies of different possible terminations are in a proportion equal to that of the concentration-weighted energies of the {111} surfaces of the pure metals, surface energies for all possible {111} terminations may be calculated. The preferable termination perpendicular to the A111 direction consists of a bilayer with three Ga atoms in the upper and three Pd atoms in the lower part. The surface energy of this termination further decreases if the Pd triplet is covered by additional Ga atom. Perpendicular to the A111 direction the lowest energy has been found for a bilayer with three Ga atoms per surface cell in the upper layer and one Ga and one Pd in the lower part. The calculated surface energies are in agreement with a simulated cleavage experiment. However, cleavage does not result in the formation of the lowest-energy surfaces, because all possible {111} cleavage planes expose a low-energy surface on one, and a high-energy surface on the other side. The prediction of Ga-terminated surfaces has been tested against the available experimental information. The calculated surface electronic density of states is in very good agreement with photo-emission spectroscopy. Calculated STM images of the most stable surfaces agree with all details of the available experimental images. The chemical reactivity of the most stable surfaces has been studied by the adsorption of CO molecules. The adsorption energies and maximum coverages calculated for the Ga-terminated surfaces permit a reasonable interpretation of the observed thermal desorption spectra, whereas for the Pd-terminated surfaces the calculated adsorption energies are far too high. © 2013 American Institute of Physics.

Benco L.,University of Vienna | Benco L.,Slovak Academy of Sciences
Journal of Catalysis | Year: 2013

The compensation effect is investigated using DFT calculations of the activation of the N2O molecule over mononuclear cations (Fe 2+, Co2+) and cationic oxo-particles (RuO2+, RuO+), identified as perspective active sites. Constrained MD simulations are used to calculate Helmholtz free energies of activation at 300 K, 420 K, and 700 K. Reaction rates calculated according to the transition state theory are used to construct Arrhenius plots (AP). Activation energies, derived from the AP, are 60.9 kJ/mol, 77.2 kJ/mol, 99.4 kJ/mol, and 105.1 kJ/mol for RuO+, Fe2+, Co2+, and RuO2+, respectively. A linear dependence between enthalpy of activation ΔH ‡ and entropy of activation ΔS‡ is observed only when the reaction exhibits the isokinetic behavior. The change of entropy of activation is approximately three orders smaller than the change of enthalpy. For the activation of N2O, a rare case of the anticompensation is observed. The reaction rates computed for the temperature range between 300 K and 700 K increase in order: RuO+ > Fe 2+ > Co2+ > RuO2+. © 2012 Elsevier Inc. All rights reserved.

Neslusan L.,Slovak Academy of Sciences
Contributions of the Astronomical Observatory Skalnate Pleso | Year: 2015

A review of observational and theoretical studies of the well-known major meteoroid stream Geminids is presented. We also give a summary of the studies of the relationship between the stream and its parent body, asteroid 3200 Phaethon.

Svoren J.,Slovak Academy of Sciences
Contributions of the Astronomical Observatory Skalnate Pleso | Year: 2015

The paper offers a look at distribution of solar activity during an average solar cycle. Activity profiles in solar cycles from 13 to 17 and from 18 to 22 were studied based on the relative sunspot numbers. The average values for both groups of cycles were derived after the standardization to the maximum monthly value. Obtained values differed minimally, allowing us to derive a uniform distribution of activity for the entire review period from 1890 to 1996. The derived model of the distribution of activity in an average solar cycle allows us to predict the maximum value of an activity cycle with an advance of approximately 5 years based only on the value obtained in the first year of the cycle. This can be of use for, e.g., the planning of long-term human activities in outer space.

Shagatova N.,Slovak Academy of Sciences
Contributions of the Astronomical Observatory Skalnate Pleso | Year: 2015

A double nature of the circumbinary matter in symbiotic systems, i. e. the presence of H0 and H+ regions, offers an opportunity to investigate both the properties of the wind from the donor star and the effect of radiation from the ionizing companion onto the surrounding material. In this contribution we explain the importance of the effect of ionization for a proper treating of the inversion problem for the wind velocity profile. The method allows us to obtain the models for total and neutral hydrogen column densities and corresponding wind velocity profiles. We describe in detail the process of modelling for the spherically symmetric wind and compare it with simpler approaches. The first application of our improved approach revealed that the effect of ionization on the column density shapes is not negligible for a wide range of orbital phases, in contrast to the assumptions in previous papers. Thus, it implies a higher concentration of the wind matter than it was supposed before.

Dubecky M.,Palacky University | Jurecka P.,Palacky University | Derian R.,Slovak Academy of Sciences | Hobza P.,Palacky University | And 3 more authors.
Journal of Chemical Theory and Computation | Year: 2013

An accurate description of noncovalent interaction energies is one of the most challenging tasks in computational chemistry. To date, nonempirical CCSD(T)/CBS has been used as a benchmark reference. However, its practical use is limited due to the rapid growth of its computational cost with the system complexity. Here, we show that the fixed-node diffusion Monte Carlo (FN-DMC) method with a more favorable scaling is capable of reaching the CCSD(T)/CBS within subchemical accuracy (<0.1 kcal/mol) on a testing set of six small noncovalent complexes including the water dimer. In benzene/water, benzene/methane, and the T-shape benzene dimer, FN-DMC provides interaction energies that agree within 0.25 kcal/mol with the best available CCSD(T)/CBS estimates. The demonstrated predictive power of FN-DMC therefore provides new opportunities for studies of the vast and important class of medium/large noncovalent complexes. © 2013 American Chemical Society.

Majtan J.,Slovak Academy of Sciences | Majtan J.,Slovak Medical University
Evidence-based Complementary and Alternative Medicine | Year: 2011

Honey has been considered as a remedy in wound healing since ancient times. However, as yet, there are inadequate supportive robust randomized trials and experimental data to fully accept honey as an effective medical product in wound care. Manuka honey has been claimed to have therapeutic advantages over other honeys. Recently, it has been documented that the pronounced antibacterial activity of manuka honey is due, at least in part, to reactive methylglyoxal (MG). The concentration of MG in manuka honeys is up to 100-fold higher than in conventional honeys. MG is a potent protein-glycating agent and an important precursor of advanced glycation end products (AGEs). MG and AGEs play a role in the pathogenesis of impaired diabetic wound healing and can modify the structure and function of target molecules. This commentary describes the concern that MG in manuka honey may delay wound healing in diabetic patients. Further detailed research is needed to fully elucidate the participation of honey/derived MG in healing diabetic ulcers. We advocate randomized controlled trials to determine efficacy and safety of manuka honey in this population. Copyright 2011 Juraj Majtan.

Mesiarova-Zemankova A.,Slovak Academy of Sciences
Information Sciences | Year: 2015

Transformation of uninorms defined on the unit interval to the bipolar scale yields bipolar t-conorms and transformation of nullnorms on the unit interval yields bipolar t-norms. We use this relation in the investigation of the structure of bipolar and multi-polar t-norms and t-conorms. We use the same transformation of the unit interval into the bipolar scale in order to obtain bipolar aggregation operators from ordinal sum t-norms and t-conorms. The extensions of these special bipolar aggregation operators generalize both multi-polar t-norms and t-conorms and therefore we call them multi-polar uninorms. Several examples of multi-polar t-conorms and uninorms are also presented. © 2015 Elsevier Inc.

Pocs J.,Slovak Academy of Sciences
Information Sciences | Year: 2012

The aim of this paper is to compare an approach of creating fuzzy concept lattices proposed by Popescu with several other approaches. Particularly, we show that this approach is in some way equivalent to the approach of Krajči called generalized concept lattices. We also give a straightforward generalization of Popescu's approach to non-homogeneous cases. © 2011 Elsevier Inc. All rights reserved.

The novel separation method, liquid chromatography under limiting conditions of desorption, LC LCD enables rapid one-step discrimination of both parent homopolymers from diblock copolymers. The low-molecular admixtures/impurities can be base-line separated, as well. The general rules for selection of the LC LCD columns are reviewed. Bare silica gel column packings are discussed in detail. Selected examples of separation are presented. They demonstrate that the principle of LC LCD separation is not affected by the particle size and initial purity of bare silica gel column packing nor by its effective pore diameter and volume. However, appropriate choice of the packing pore size facilitates base-line separation of particular sample constituents. Important may be the column history; columns saturated with previously adsorbed polymers may lose their performance. Up to a certain limit, success of the LC LCD separation does not depend on the column efficiency and reasonable results can be obtained even with the columns packed with rather big particles. This indicates possibility of the large-scale preparative applications and feasibility of the high-speed LC LCD separations. © 2009 Elsevier Ltd. All rights reserved.

Skopal A.,Slovak Academy of Sciences | Tomov N.A.,Bulgarian Academy of Science | Tomova M.T.,Bulgarian Academy of Science
Astronomy and Astrophysics | Year: 2013

Context. Detection of collimated ejection from white dwarfs (WD) in symbiotic binaries is very rare and has employed a variety of methods in X-ray, radio, optical imagery, and spectroscopy. To date, its signature in the optical spectra has only been recorded for four objects (MWC 560, Hen 3-1341, StHα 190, and Z And). Aims. We present the first observational evidence of highly-collimated bipolar ejection from the symbiotic binary BF Cyg, which developed during its current (2006-12) active phase, and determine their physical parameters. Methods. We monitored the outburst with the optical high-resolution spectroscopy and multicolour UBVRCIC photometry. Results. During 2009, three years after the 2006-eruption of BF Cyg, satellite components to Hα and Hβ lines emerged in the spectrum. During 2012, they became stable and were located symmetrically with respect to the main emission core of the line. Spectral properties of these components suggest bipolar ejection collimated within an opening angle of ≲15°, whose radiation is produced by an optically thin medium with the emission measure of 1-2 × 1059 (d/3.8 kpc)2 cm-3. Conclusions. Formation of the collimated ejection a few years after the eruption and its evolution on a time scale of years at a constant optical brightness can aid us in better understanding the accretion process during the active phases of symbiotic stars. © 2013 ESO.

Sadovsky Z.,Slovak Academy of Sciences
Safety and Reliability: Methodology and Applications - Proceedings of the European Safety and Reliability Conference, ESREL 2014 | Year: 2015

The contribution addresses combination of time-variant actions, particularly snow and wind loads on a variety of structural design situations. The simplified Turkstra's rule commonly used for probabilistic calibration of standardized design procedures is compared with a an approach employing a direct inclusion of joint action effect. The study is carried out for three representative frames of low-rise industrial buildings designed such that both snow or wind loads could be relevant. For each frame three levels of permanent load realized as light, medium and heavy weight roofs are considered. The frames are designed to the lifetime of 50 years and reliability index βt = 3.8 by FORM. The comparison of the values of the resulting design variable-the nominal plastic moment is presented. © 2015 Taylor & Francis Group.

Bacharova L.,International Laser Center | Szathmary V.,Slovak Academy of Sciences | Mateasik A.,International Laser Center
Journal of Electrocardiology | Year: 2011

By definition, the electrocardiographic (ECG) patterns of left bundle-branch block (LBBB) represent distinctive changes in duration and shape of the QRS complex caused by intraventricular conduction delay in the left ventricle (LV) due to structural abnormalities in the His-Purkinje conduction system and/or ventricular myocardium. However, impaired conduction in the working myocardium is not taken into consideration in the practical ECG diagnosis. Because the degree of LV myocardium impairment could be of importance for clinical evaluation of patients, we studied the effects of blocked and of delayed onsets of activation in the LV to simulate complete and incomplete LBBBs and slowed conduction in the LV myocardium by applying an analytical computer model. We demonstrated that typical LBBB patterns were caused both by block or delay in the onset of the LV activation, as well as by impaired conduction in the myocardium itself while maintaining the location and onset of the LV activation. The most important difference was the absence of initial anteriorly oriented electrical forces in cases of the simulated complete LBBB and of incomplete LBBB if the onset of LV activation was delayed (≥6 milliseconds). Under the conditions defined in this model that did not consider myocardial infarction, the presence of initial anteriorly oriented electrical forces was indicative of preserved conduction in the left bundle and of impaired conduction in LV working myocardium. Conclusion: The elucidation of the participation of working myocardium impairment in the intraventricular conduction delay in the LV could be of vital significance for the clinical management of patients with LBBB patterns, for example, indicated for resynchronization therapy. Copyright © 2011 Published by Elsevier Inc. All rights reserved.

Pardo E.,Slovak Academy of Sciences
Superconductor Science and Technology | Year: 2016

Screening currents caused by varying magnetic fields degrade the homogeneity and stability of the magnetic fields created by REBCO coated conductor coils. They are responsible for the AC loss; which is also important for other power applications containing windings, such as transformers, motors and generators. Since real magnets contain coils exceeding 10000 turns, accurate modeling tools for this number of turns or above are necessary for magnet design. This article presents a fast numerical method to model coils with no loss of accuracy. We model a 10400-turn coil for its real number of turns and coils of up to 40000 turns with continuous approximation, which introduces negligible errors. The screening currents, the screening current induced field (SCIF) and the AC loss is analyzed in detail. The SCIF is at a maximum at the remnant state with a considerably large value. The instantaneous AC loss for an anisotropic magnetic-field dependent J c is qualitatively different than for a constant J c, although the loss per cycle is similar. Saturation of the magnetization currents at the end pancakes causes the maximum AC loss at the first ramp to increase with J c. The presented modeling tool can accurately calculate the SCIF and AC loss in practical computing times for coils with any number of turns used in real windings, enabling parameter optimization. © 2016 IOP Publishing Ltd.

Thorson M.K.,University of Utah | Majtan T.,Slovak Academy of Sciences | Kraus J.P.,University of Colorado at Denver | Barrios A.M.,University of Utah
Angewandte Chemie - International Edition | Year: 2013

Buzzing with activity: A hydrogen sulfide selective fluorogenic probe, 7-azido-4-methylcoumarin (AzMC), serves as a highly sensitive assay for cystathionine β-synthase activity, and is suitable for the high-throughput discovery of novel enzyme inhibitors. Copyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Stress-induced activation of the hypothalamic-pituitary-adrenal axis and sympathoadrenal system is precisely regulated by well-documented negative feedback mechanisms. These include direct negative feedback effect of glucocorticoids on brain structures regulating the hypothalamic-pituitary-adrenal axis activity. However, since the blood-brain-barrier is impermeable to circulating catecholamines, the role of circulating epinephrine and norepinephrine in feedback regulation of the sympathoadrenal system activity is unclear. Here we show that vagal innervation of the adrenal medulla combined with the presence of β-adrenergic receptors on vagal sensory neurons, the epinephrine-induced activation of vagal afferents, and increased plasma epinephrine levels following subdiaphragmatic vagotomy indicate that sensory fibers of the vagus nerve participate in the monitoring of plasma and tissue catecholamine concentrations. Furthermore, it shows that signaling transmitted by vagal afferents regulates sympathoadrenal system activity at the level of the brain. Therefore, we propose that vagal sensory fibers, directly activated by epinephrine and norepinephrine, represent the afferent limb of a  negative feedback loop that adjusts the activity of the sympathoadrenal system according to actual plasma and tissue catecholamine levels.

Mucka P.,Slovak Academy of Sciences
Journal of Testing and Evaluation | Year: 2016

Road classification of longitudinal road unevenness was proposed based on road elevation power spectral density (PSD). The proposal is based on two spectrum parameters (unevenness index and waviness): vehicle model vibration response, and vehicle velocity. A planar model of a personal car with 12 degrees-of-freedom (DOF) was used and four vertical vibration responses were considered. Ride comfort quantities in terms of the frequencyweighted acceleration on driver and passenger seats and ride safety/pavement dynamic load quantities as a dynamic load coefficient (DLC) on the front and rear axle were taken into account. A tire-enveloping model was used as representative of tire-road contact. This approach was compared with pure tire-road point contact and moving averaged profile. Data was obtained for 1600 real road sections and three different velocities. The results indicated marked differences in comparison with the road classification based on a constant waviness according to the ISO 8608 standard. © 2016 ASTM Int'l (all rights reserved).

Balaz M.,Slovak Academy of Sciences
28th Norchip Conference, NORCHIP 2010 | Year: 2010

The aim of the presented work is to improve the quality of testing of SoC digital cores surrounded with test wrappers. The paper presents a new effective delay fault test generation method for the transition faults based on the skewed-load test. The generated delay fault test can be applied to a SoC core through a test wrapper architecture with only a simple boundary scan chain. This eliminates the necessity to use an enhanced boundary scan chain for the application of the delay fault test. The effectiveness of the developed method for a transition delay test generation was verified on the set of combinational and sequential circuits. The experiments show a significant reduction of test vector application time. ©2010 IEEE.

Pritychenko B.,Brookhaven National Laboratory | Betak E.,Slovak Academy of Sciences | Singh B.,McMaster University | Totans J.,Brookhaven National Laboratory
Nuclear Data Sheets | Year: 2014

The Nuclear Science References (NSR) database together with its associated Web interface, is the world's only comprehensive source of easily accessible low- and intermediate-energy nuclear physics bibliographic information for more than 210,000 articles since the beginning of nuclear science. The weekly-updated NSR database provides essential support for nuclear data evaluation, compilation and research activities. The principles of the database and Web application development and maintenance are described. Examples of nuclear structure, reaction and decay applications are specifically included. The complete NSR database is freely available at the websites of the National Nuclear Data Center http://www.nndc.bnl.gov/nsr and the International Atomic Energy Agency http://www-nds.iaea.org/nsr. © 2014 Elsevier Inc.

Samaj L.,Slovak Academy of Sciences
Journal of Statistical Physics | Year: 2015

Macromolecules, when immersed in a polar solvent like water, become charged by a fixed surface charge density which is compensated by “counter-ions” moving out of the surface. Such classical particle systems exhibit poor screening properties at any temperature and the trivial bulk regime (far away from the charged surface) with no particles, so the validity of standard Coulomb sum rules is questionable. In the present paper, we concentrate on the two-dimensional version of the model with the logarithmic interaction potential. We go from the finite disc to the semi-infinite planar geometry. The system is exactly solvable for two values of the coupling constant Γ: in the Poisson–Boltzmann mean-field limit (Formula Presented.) and at the free-fermion point (Formula Presented.). We show that the finite-size expansion of the free energy does not contain universal term as is usual for Coulomb fluids. For the coupling constant being an arbitrary positive even integer, using an anticommuting representation of the partition function and many-body densities we derive a sequence of sum rules. As a result, the contact density of counter-ions at the wall is available for the disc. The amplitude function, which characterizes the asymptotic inverse-power law behavior of the two-body density along the wall, is found to be related to the particle density profile. The dielectric susceptibility tensor, calculated exactly for an arbitrary coupling and the particle number, exhibits the anticipated disc value in the thermodynamic limit, in spite of zero contribution from the bulk region. Some of the results obtained in the Poisson–Boltzmann limit are generalized to an arbitrary Euclidean dimension. © 2015, Springer Science+Business Media New York.

Musatov A.,University of Texas Health Science Center at San Antonio | Musatov A.,Slovak Academy of Sciences
Journal of Biological Inorganic Chemistry | Year: 2013

The effect of heparin on peroxidation of cardiolipin (CL) initiated by ferrous iron was studied in vitro using detergent-solubilized CL, liposomal CL, or CL bound to isolated cytochrome c oxidase (CcO). Heparin increased both the rate and the extent of CL peroxidation for detergent-solubilized CL and for CcO-bound CL. The effect of heparin was time- and concentration-dependent as monitored by the formation of conjugated dienes or thiobarbituric acid reactive substances. The results showed great similarity between the effect of heparin and the effect of certain iron chelators, such as ADP, on phospholipid peroxidation. Heparin increased the peroxidation of CcO-bound CL only when tertiary butyl hydroperoxide was also present. The enzyme activity of the resulting CcO complex decreased 25 %, in part due to peroxidation of functionally important CL. In contrast to peroxidation of detergent-solubilized CL, peroxidation of liposomal CL was inhibited by heparin, suggesting that the effect of heparin and ferrous iron depends on their proximity to the acyl chains of CL. © 2013 SBIC.

Cmorik R.,University of P.J. Safarik | Jiraskova G.,Slovak Academy of Sciences
Lecture Notes in Computer Science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics) | Year: 2012

We give a characterization of nondeterministic automata accepting suffix-free languages, and a sufficient condition on deterministic automata to accept suffix-free languages. Then we investigate the state complexity of basic operations on binary suffix-free regular languages. In particular, we show that the upper bounds on the state complexity of all the boolean operations as well as of Kleene star are tight in the binary case. On the other hand, we prove that the bound for reversal cannot be met by binary languages. This solves several open questions stated by Han and Salomaa (Theoret. Comput. Sci. 410, 2537-2548, 2009). © 2012 Springer-Verlag Berlin Heidelberg.

Fedorov Yu.,Ukrainian Academy of Sciences | Stehlik M.,Slovak Academy of Sciences
Journal of Physics B: Atomic, Molecular and Optical Physics | Year: 2010

The acceleration of energetic particles is investigated using the kinetic equation in a statistically anisotropic helical turbulent magnetic field in the diffusion approximation. It is known that large-scale magnetic and electric fields are generated in a medium with statistically anisotropic magnetohydrodynamic turbulence. The particle acceleration by the large-scale electric field can be very efficient if the magnetic helicity of a turbulent medium is sufficiently high. The effectiveness of this acceleration mechanism is compared with the Fermi acceleration of the second order. The steady-state cosmic ray energetic spectra as well as their evolution during their approach to an equilibrium state of both acceleration processes are studied. © 2010 IOP Publishing Ltd.

Ilkovic V.,Slovak Academy of Sciences
Journal of Magnetism and Magnetic Materials | Year: 2015

Magnetic reorientation in three layer antiferromagnetic films with simple cubic lattice and with (001) surfaces is investigated theoretically. We applied the Green function method to the Heisenberg model. Self-consistent calculations for layer magnetizations and the surface reorientation temperatures for different exchange anisotropy and single-ion anisotropy parameters are carried out. Particularly, we compare the effect of both mentioned anisotropies on the surface reorientation temperature. © 2014 Published by Elsevier B.V.

Farkas R.,Slovak Academy of Sciences
Biochimica et Biophysica Acta - General Subjects | Year: 2015

Background While apocrine secretion was among the earliest secretory mechanisms to be identified, its underlying basis remains poorly understood. Scope of review This review reappraises our understanding of apocrine secretion using insights about apocrine secretion from the salivary glands of Drosophila, in which molecular genetic analyses have provided a glimmer of hope for elucidating the mechanistic aspects of this fundamental process. Major conclusions In contrast to the well-defined process of exocytosis, apocrine secretion is non-vesicular transport and secretory pathway that entails the loss of part of the cytoplasm. It often involves apical protrusions and generates cytoplasmic fragments inside a secretory lumen. In its most intense phase this process is accompanied by the release of large fragments of cellular structures and entire organelles that include mitochondria, Golgi, and portions of the endoplasmic reticulum, among others. Proteomic analyses revealed that the secretion is composed of hundreds to thousands of membranous, cytoskeletal, microsomal, mitochondrial, ribosomal, and even nuclear as well as nucleolar proteins. Strikingly, although many nuclear proteins are released, the nuclear deoxyribonucleic acid itself remains intact. In spite of this complexity, it appears that several protein components of apocrine secretion are identical, regardless of the location of the apocrine gland. General significance This type of secretion appears to be common to many, if not all, barrier epithelial tissues including skin derivatives and the epididymis, and is implicated also in lung/bronchi and intestinal epithelium. Apocrine secretion is a mechanism that provides the en masse delivery of a very complex proteinaceous mixture from polarized epithelial tissues to allow for communication at exterior interfaces. © 2015 Elsevier B.V. All rights reserved.

Saniga M.,Slovak Academy of Sciences | Levay P.,Budapest University of Technology and Economics
EPL | Year: 2012

Mermin's pentagram, a specific set of ten three-qubit observables arranged in quadruples of pairwise commuting ones into five edges of a pentagram and used to provide a very simple proof of the Kochen-Specker theorem, is shown to be isomorphic to an ovoid (elliptic quadric) of the three-dimensional projective space of order two, PG(3, 2). This demonstration employs properties of the real three-qubit Pauli group embodied in the geometry of the symplectic polar space W(5, 2) and rests on the facts that: 1) the four observables/operators on any of the five edges of the pentagram can be viewed as points of an affine plane of order two, 2) all the ten observables lie on a hyperbolic quadric of the five-dimensional projective space of order two, PG(5, 2), and 3) that the points of this quadric are in a well-known bijective correspondence with the lines of PG(3, 2). Copyright © EPLA, 2012.

Nikitovic D.,University of Crete | Juranek I.,Slovak Academy of Sciences | Wilks M.F.,University of Basel | Tzardi M.,University of Crete | And 2 more authors.
Chest | Year: 2014

The mechanisms of anthracycline-dependent cardiotoxicity have been studied widely, with the suggested principal mechanism of anthracycline damage being the generation of reactive oxygen species by iron-anthracycline complexes, leading to lipid peroxidation and membrane damage. An increasing number of researchers studying cardiovascular events associated with anthracycline-based chemotherapy are addressing cardiac extracellular matrix (ECM) remodeling. The heart is an effi cient muscular pump, with the cardiomyocytes and intramural coronary vasculature of the heart tethered in an ECM consisting of a network of fi brillar, structural proteins, mostly collagens. Increasing evidence suggests that the ECM plays a complex and diverse role in the processes initiated by anthracycline-class drugs that lead to cardiac damage. This review discusses adverse myocardial remodeling induced by anthracyclines and focuses on their mechanisms of action. © 2014 AMERICAN COLLEGE OF CHEST PHYSICIANS.

Tomasovych A.,Slovak Academy of Sciences | Jablonski D.,University of Chicago | Berke S.K.,Siena College | Krug A.Z.,Flint Hill School | Valentine J.W.,University of California at Berkeley
Global Ecology and Biogeography | Year: 2015

Aim: Species living at latitudes that have greater annual temperature variations are expected to achieve broader geographic ranges than species living at latitudes that have smaller annual temperature variations, generating a positive relationship between range size and latitude (Rapoport's rule). However, this prediction fails to take into account the greater latitudinal extent of tropical temperatures relative to those at higher latitudes. Here we model the contributions of the broader latitudinal extent of equal-temperature habitats at low latitudes and the greater annual temperature variation at high latitudes to the range size-latitude relationship, and test whether the latitudinal variation in geographic range size in marine bivalves can be explained by models that account for both annual temperature variation and the steepness of latitudinal thermal gradients. Location: Western Pacific, eastern Pacific and western Atlantic. Methods: We use a null model where geographic ranges are placed on the ocean surface independently of thermal gradients, and a range-expansion model where the minimum and maximum temperatures encompassed by the geographic range of a species (macroecological thermal ranges) are positively related to annual temperature minima and maxima at the location where the species originated. We compare results with a database containing 40,820 occurrences of 4760 marine bivalve species. Result: Models incorporating temperature-limited range expansion along realistic thermal gradients predict an inverse relationship between range size and latitude, in opposition to Rapoport's rule. The distribution patterns of marine bivalves match this prediction. Main conclusions: The poleward trend in latitudinal range size is determined by the nonlinearity of the latitudinal gradient of temperature minima and maxima and less by the latitudinal gradient of the local seasonal range in temperatures. Although tropical species do have narrower macroecological thermal ranges than high-latitude species, the nearly constant temperatures over wide areas of the tropics allow tropical species to achieve broad latitudinal ranges. © 2014 John Wiley & Sons Ltd.

Halas R.,Palacky University | Pocs J.,Palacky University | Pocs J.,Slovak Academy of Sciences
Information Sciences | Year: 2015

The main aim of this paper is to introduce the preference relations on generalized one-sided concept lattices, which represent a fuzzy generalization of FCA with classical object clusters and fuzzy attributes. In our case a preference relation is modeled by a linear well quasi-order on the set of all attributes. We describe concept forming operators based on a Galois connection, which is defined between the power set of objects and the fuzzy sets of attributes with lexicographic order induced by the preference relation. The representation theorem for such kind of concept lattices is also presented. © 2015 Elsevier Inc. All rights reserved.

Raith M.,University of Regensburg | Stano P.,Slovak Academy of Sciences | Stano P.,University of Basel | Fabian J.,University of Regensburg
Physical Review B - Condensed Matter and Materials Physics | Year: 2012

Highly accurate numerical results of phonon-induced two-electron spin relaxation in silicon double quantum dots are presented. The relaxation, enabled by spin-orbit coupling and the nuclei of 29Si (natural or purified abundance), is investigated for experimentally relevant parameters, the interdot coupling, the magnetic field magnitude and orientation, and the detuning. We calculate relaxation rates for zero and finite temperatures (100 mK), concluding that our findings for zero temperature remain qualitatively valid also for 100 mK. We confirm the same anisotropic switch of the axis of prolonged spin lifetime with varying detuning as recently predicted in GaAs. Conditions for possibly hyperfine-dominated relaxation are much more stringent in Si than in GaAs. For experimentally relevant regimes, the spin-orbit coupling, although weak, is the dominant contribution, yielding anisotropic relaxation rates of at least two orders of magnitude lower than in GaAs. © 2012 American Physical Society.

Jencova A.,Slovak Academy of Sciences
Journal of Mathematical Physics | Year: 2012

A generalized channel is a completely positive map that preserves trace on a given subspace. We find conditions under which a generalized channel with respect to a positively generated subspace J is an extreme point in the set of all such generalized channels. As a special case, this yields extremality conditions for quantum protocols. In particular, we obtain new extremality conditions for quantum 1-testers with 2 outcomes, which correspond to yes/no measurements on the set of quantum channels. © 2012 American Institute of Physics.

Capkovic F.,Slovak Academy of Sciences
Lecture Notes in Computer Science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics) | Year: 2016

Discrete event systems (DES) control based on interpreted Petri nets (IPN) is presented in this paper. While place/transition Petri nets (P/T PN) are usually used for modelling and control in case of controllable transitions and measurable places, the IPN-based models yield the possibility for the control synthesis also in case when P/T PN models contain some uncontrollable transitions and unmeasurable places. The creation of the IPN model from such a P/T PN model is introduced and the control synthesis is performed. The illustrative examples as well as the case study on a robotized assembly cell are introduced. © Springer-Verlag Berlin Heidelberg 2016.

Baruffa F.,University of Regensburg | Stano P.,Slovak Academy of Sciences | Stano P.,University of Arizona | Fabian J.,University of Regensburg
Physical Review B - Condensed Matter and Materials Physics | Year: 2010

The influence of the spin-orbit interactions on the energy spectrum of two-electron laterally coupled quantum dots is investigated. The effective Hamiltonian for a spin qubit pair proposed in Baruffa [Phys. Rev. Lett. 104, 126401 (2010)]10.1103/PhysRevLett.104.126401 is confronted with exact numerical results in single and double quantum dots in zero and finite magnetic field. The anisotropic exchange Hamiltonian is found quantitatively reliable in double dots in general. There are two findings of particular practical importance: (i) the model stays valid even for maximal possible interdot coupling (a single dot), due to the absence of a coupling to the nearest excited level, a fact following from the dot symmetry. (ii) In a weak-coupling regime, the Heitler-London approximation gives quantitatively correct anisotropic exchange parameters even in a finite magnetic field, although this method is known to fail for the isotropic exchange. The small discrepancy between the analytical model (which employs the linear Dresselhaus and Bychkov-Rashba spin-orbit terms) and the numerical data for GaAs quantum dots is found to be mostly due to the cubic Dresselhaus term. © 2010 The American Physical Society.

Consistent estimators of the asymptotic covariance matrix of vectors of U-statistics are used in constructing asymptotic confidence regions for vectors of Kendall's correlation coefficients corresponding to various pairs of components of a random vector. The regions are products of intervals computed by means of a critical value from multivariate normal distribution. The regularity of the asymptotic covariance matrix of the vector of Kendall's sample coefficients is proved in the case of sampling from continuous multivariate distribution under mild conditions. The results are applied also to confidence intervals for the coefficient of agreement. The coverage and length of the obtained (multivariate) product of intervals are illustrated by simulation.

Strbak V.,Slovak Academy of Sciences
Cellular Physiology and Biochemistry | Year: 2011

Cell swelling induces peptide exocytosis using unique signaling pathway. Hyposmotic-induced secretion in normal cells is not mediated by specific receptors, is independent from extra and intracellular Ca 2+, sodium and potassium channels activity, prostaglandins, leukotriens, does not involve cytoskeleton, cAMP generation, phospholipase A 2, G proteins, protein kinase C. It is promoted by swelling of the secretory vesicles. Resistance to endogenous inhibitors is frequent attribute of this type of secretion. Swelling-induced secretion involves also secretory vesicles not involved in conventional stimulation. Hyposmosis-induced insulin secretion is more sensitive to high cellular cholesterol than conventional one suggesting substantial difference between mechanisms. Participation of sequential exocytosis as dominating mechanism in swelling-induced exocytosis is hypothesized. Signaling and response in tumor cells often differs from native cells and varies markedly between cell lines. Pathogenetic implications: cell swelling could be involved in alcohol induced hypoglycemia in diabetic patients and release of peptides from pituitary and neurons. Swelling-induced products could be mediators of ischemic preconditioning involved also in protection of diabetic heart. Swelling-induced exocytosis is an ancient mechanism generally present in cells; in cells engaged in water and salt regulation is covered by specific response mediated by specific signaling. Disturbance of specific response leads to swelling-induced - inappropriate secretion of antidiuretic hormone - SIADH. Copyright © 2011 S. Karger AG, Basel.

Capek I.,Slovak Academy of Sciences
Polymer - Plastics Technology and Engineering | Year: 2015

The preparation and characterization of noble metal nanoparticles that are coated by organic shells for the covalent immobilization of biopolymers were described. Plasmonic nanoparticles demonstrate unique size-dependent optical and photothermal properties due to the collective oscillation of free electrons in their conduction bands. The intensity of absorption and scattering of noble metal nanoparticles is significantly higher than most absorbing and scattering organic molecular dyes, which makes them excellent candidates as contrast agents in imaging. Cylindrical gold nanorods also demonstrate a tunable photothermal response to near infrared light as a function of nanoparticle aspect ratio. Organic functional groups on the nanoparticles allow the coupling of organic molecules to their shells. Several synthetic approaches to couple biomolecules to metal nanoparticles and to use the hybrid assemblies for various bioanalytical applications have been reported. © Taylor & Francis Group, LLC.

Benus S.,Slovak Academy of Sciences
3rd IEEE International Conference on Cognitive Infocommunications, CogInfoCom 2012 - Proceedings | Year: 2012

This paper provides a first analysis of the Slovak word [no] that is extremely ambiguous in terms of pragmatic and discourse functions and can correspond to 'okay', 'yes', 'well', 'mhm', 'so', and others. We report that the function of backchannel/continuer is the most easily disambiguated by the pitch contour, duration, and other features. Other functions, while also frequent in our corpus, require more sophisticated multi-factor analyses for identifying best disambiguating features. © 2012 IEEE.

Bajnok Z.,Hungarian Academy of Sciences | Samaj L.,Slovak Academy of Sciences
Acta Physica Slovaca | Year: 2011

This is the third part of a three-volume introductory course about integrable systems of interacting bodies. The emphasis is put onto the method of Thermodynamic Bethe ansatz. Two kinds of integrable models are studied. Systems of itinerant electrons, forming a part of Condensed Matter Physics, involve the Hubbard lattice model of electrons with short-ranged one-site interactions (Sect. 20) and the s-d exchange Kondo model (Sect. 21), describing the scattering of conduction electrons on a spin-s impurity. Methods and basic concepts used in Quantum Field Theory are explained on the integrable (1 + 1)-dimensional sine-Gordon model. We start with the classical description of the model in Sect. 22, analyze its finite energy field configurations (soliton, anti-soliton and breathers) and show its classical integrability. The model is quantized by using two schemes: the conformal (Sect. 23) and Lagrangian (Sect. 24) quantizations. The scattering matrix of the sine-Gordon theory is derived at the full quantum level in the bootstrap scheme and is compared to its classical limit in Sect. 25. The parameters of the scattering matrix are related to those of the Lagrangian by calculating the ground-state energy in an applied magnetic field in two ways: Conformal perturbation theory and Thermodynamic Bethe ansatz (Sect. 26). The relation of the sine-Gordon theory to the XXZ Heisenberg model, which provides a complete solution of the sine-Gordon model in a finite volume, is pointed out in Sect. 27. The obtained results are applied in Sect. 28. to the derivation of the exact thermodynamics for the (symmetric) two-component Coulomb gas; this is the first classical two-dimensional fluid with exactly solvable thermodynamics.

Budagovskyi A.I.,Russian Academy of Sciences | Novak V.,Slovak Academy of Sciences
Journal of Hydrology and Hydromechanics | Year: 2011

Basic information about the evapotranspiration and its components is presented. System of equations describing the transport of water and energy in the soil - plant continuum is analyzed. The system of five differential equations with five unknowns is proposed, describing transport of heat and water vapour within the plant canopy, including exchange processes among the leaves and the atmosphere, vertical transport of the heat, water vapour and the energy balance.

Bartanusz V.,University of Texas Health Science Center at San Antonio | Jezova D.,Slovak Academy of Sciences | Alajajian B.,University of Texas Health Science Center at San Antonio | Digicaylioglu M.,University of Texas Health Science Center at San Antonio
Annals of Neurology | Year: 2011

The blood-spinal cord barrier (BSCB) is the functional equivalent of the blood-brain barrier (BBB) in the sense of providing a specialized microenvironment for the cellular constituents of the spinal cord. Even if intuitively the BSCB could be considered as the morphological extension of the BBB into the spinal cord, evidence suggests that this is not so. The BSCB shares the same principal building blocks with the BBB; nevertheless, it seems that morphological and functional differences may exist between them. Dysfunction of the BSCB plays a fundamental role in the etiology or progression of several pathological conditions of the spinal cord, such as spinal cord injury, amyotrophic lateral sclerosis, and radiation-induced myelopathy. This review summarizes current knowledge of the morphology of the BSCB, the methodology of studying the BSCB, and the potential role of BSCB dysfunction in selected disorders of the spinal cord, and finally summarizes therapeutic approaches to the BSCB. © 2011 American Neurological Association.

Jiraskova G.,Slovak Academy of Sciences | Masopust T.,Academy of Sciences of the Czech Republic
Lecture Notes in Computer Science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics) | Year: 2010

We continue the investigation of union-free regular languages that are described by regular expressions without the union operation. We also define deterministic union-free languages as languages recognized by one-cycle-free-path deterministic finite automata, and show that they are properly included in the class of union-free languages. We prove that (deterministic) union-freeness of languages does not accelerate regular operations, except for the reversal in the nondeterministic case. © 2010 Springer-Verlag Berlin Heidelberg.

Kalinak P.,Slovak Academy of Sciences
Acta Physica Polonica B, Proceedings Supplement | Year: 2012

We have studied the K 0 S and Λ particles production in pp interactions at √s = 7 TeV and Pb-Pb collisions at √S NN = 2.76 TeV. The p T and centrality dependence of the Λ/K 0 S ratio are presented and analyzed. Our results are compared with the previous results obtained in √s = 0.9 TeV pp collisions from ALICE experiment and with the Au-Au results from the STAR experiment at √s NN = 0.2 TeV.

Trnka A.,University of Trnava | Prokop P.,University of Trnava | Prokop P.,Slovak Academy of Sciences
Animal Behaviour | Year: 2012

The close resemblance between the common cuckoo, Cuculus canorus, and the Eurasian sparrowhawk, Accipiter nisus, is often viewed as Batesian mimicry evolved by the cuckoo in response to the aggression of its host. However, the effectiveness of such mimicry is poorly known. We examined cuckoo-hawk discrimination ability in the great reed warbler, Acrocephalus arundinaceus, a well-known and aggressive cuckoo host. We measured the responses of birds to three combinations of simultaneously presented taxidermic mounts of the cuckoo, sparrowhawk and turtle dove, as a harmless control, placed near their nests. Great reed warblers clearly discriminated the two enemies from the innocuous species. They always attacked cuckoos and sparrowhawks more often than turtle doves suggesting they considered both a danger to their broods. However, when we confronted the tested birds with the simultaneously presented mounts of these species, the parents attacked the cuckoo more frequently than the sparrowhawk. The results revealed that although great reed warblers attacked both cuckoo and sparrowhawk mounts near their nest, they were able to discriminate between them. This may suggest that if cuckoos had evolved the visual mimicry of a sparrowhawk to avoid host attacks, this mimicry may be unsuccessful not only because it is imperfect and hosts can learn to discriminate but also because of the generalized nest defence of more aggressive hosts. © 2011 The Association for the Study of Animal Behaviour.

Pocs J.,Slovak Academy of Sciences | Pocs J.,Technical University of Kosice
Information Sciences | Year: 2012

We provide a generalization of fuzzy concept lattices based on so-called weak Galois connections. Generalization is that instead of dually isomorphic closure systems we consider dually isomorphic retracts of complete lattices. We also give a generalization of the concept lattices with hedges, proposed by Bělohlávek and Vychodil, based on composition of interior operators with Galois connections. © 2012 Elsevier Inc. All rights reserved.

Hryha E.,Chalmers University of Technology | Dudrova E.,Slovak Academy of Sciences | Nyborg L.,Chalmers University of Technology
Journal of Materials Processing Technology | Year: 2012

Changes of atmosphere composition during sintering of water atomized powder prealloyed with Mn and Cr (up to 2% of both) were studied. Increasing sensitivity to atmosphere purity with increasing alloying elements content was registered. Continuous monitoring of sintering atmosphere composition (CO/CO 2/H 2O) indicates three critical stages during the heating up to final sintering temperature: the importance of rapid atmosphere purification after lubricant decomposition and removal; the reduction of the iron oxide layer by hydrogen at temperatures up to ∼500 °C and by carbon at temperatures around ∼720 °C; the reduction of the spinel oxides on the powder surface at above 900 °C and further reduction of thermodynamically stable surface oxides and mixed internal oxides close to the sintering temperature. The measured ratio of CO/CO 2 indicates favorable thermodynamic conditions for reduction of stable oxides as (Cr,Mn) xO y close to sintering temperature (1120 °C) for the applied sintering conditions. The experimental results were confirmed by modeling the metal-gas interactions using the thermodynamic/thermochemical softwares ThermoCalc and HSC Chemistry. The modeling indicates the significance of maintaining a sintering atmosphere with high reducing potential during heating stage for minimizing oxidation before high-temperature carbothermal reduction starts. © 2011 Elsevier B.V. All rights reserved.

Budagovskyi A.I.,Russian Academy of Sciences | Novak V.,Slovak Academy of Sciences
Journal of Hydrology and Hydromechanics | Year: 2011

Evaporation of water from the soil is described and quantified. Formation of the soil dry surface layer is quantitatively described, as a process resulting from the difference between the evaporation and upward soil water flux to the soil evaporating level. The results of evaporation analysis are generalized even for the case of water evaporation from the soil under canopy and interaction between evaporation rate and canopy transpiration is accounted for. Relationships describing évapotranspiration increase due to evaporation of the water intercepted by canopy are presented. Indirect methods of evapotranspiration estimation are discussed, based on the measured temperature profiles and of the air humidity, as well as of the net radiation and the soil heat fluxes.

Mucka P.,Slovak Academy of Sciences
Journal of Transportation Engineering | Year: 2012

This study presents the regression relationships between two commonly used indicators of longitudinal road unevenness, the international roughness index (IRI) and the straightedge index. A total of 290 real longitudinal road-profile records were processed. The asphalt-concrete and cement-concrete road surfaces were analyzed separately. Five differently defined straightedge indexes, i.e., the deviations between straightedge and profiles, were considered. The one-parameter linear approximation without an absolute term seems to be an appropriate model for fitting the unevenness indexes relation. The conversion relationships between five differently defined straightedge indexes were derived. The results were calculated as a function of a straightedge length in the range of 3 to 7.8 m. The two-parameter power function was shown to be the most suitable approximation model of the straightedge indexes dependence on the straightedge length. The analyzed influence of the different slab lengths of cement-concrete profiles on the conversion relationships indicated the marginal impact for the typical slab lengths. © 2012 American Society of Civil Engineers.

Krajci M.,Slovak Academy of Sciences | Krajci M.,University of Vienna | Hafner J.,University of Vienna
Philosophical Magazine | Year: 2011

While the surfaces of ordinary crystals provide only a few inequivalent adsorption sites, the complex landscape of the surfaces of quasicrystals and their approximants provides a rich variety of different adsorption sites. Recently, Armbruster et al. reported that Al13Co4, whose structure is closely related to decagonal Al-Ni-Co quasicrystals, is an efficient and selective hydrogenation catalyst for alkynes. In the present work, the hydrogenation of acetylene to ethylene on the (100) surface of Al 13Co4 has been studied using ab initio density-functional simulations. Surprisingly, the stable cleavage surface of Al13Co 4 is strongly corrugated. The surface is covered by zig-zag chains of edge-sharing Al pentagons, each centered on a Co atom and separated from neighboring chains by wide troughs. The binding energies for adsorption and co-adsorption of H2 and C2H2 molecules at various surface sites have been calculated. Surprisingly, in the energetically most favorable configuration, acetylene is bound in a di-δ configuration to two Al atoms, not to the Co atom. We have searched for the optimal reaction pathway for the dissociatible adsorption of hydrogen and for the hydrogenation of acetylene to vinyl, ethylene by a Langmuir-Hinshelwood mechanism. The energetic barriers for all reaction steps were calculated by the nudged-elastic-band method. It was found that the energetic barrier of any reaction step does not exceed 0.65 eV (63 kJ/mol). This value is lower than the activation energies for acetylene to ethylene hydrogenation over a Pd catalyst where barriers of 78 kJ/mol and 85 kJ/mol were reported for the rate-determining steps. © 2011 Taylor & Francis.

A new approach to polymer self-assembly was presented recently [M. Sedlák, Č. Koňák, J. Dybal, Macromolecules2009, 2, 7430-7438 and 7439-7446.](1, 2) where stable polymeric nanoparticles were formed from poly(ethylacrylic acid) homopolymers without any assembly triggering additives, simply by heating polymer solution under conditions of thermosensitivity to certain temperature. In the current Article, we present successful results on poly(propylacrylic acid), which is a more hydrophobic polymer. We also present results on a less hydrophobic polymer from this series, poly(methacrylic acid), from which nanoparticles cannot be formed. Comparison of results on all three polymers gives a solid physicochemical insight and supports the molecular mechanism of the self-assembly previously suggested: The solvent quality gradually worsens upon heating of a thermosensitive polymer solution, and polymer-polymer contacts are preferred over polymer-solvent contacts, which leads to the formation of polymer assemblies. The presence of a significant amount of charge on chains prevents macroscopic phase separation. Upon subsequent cooling to laboratory temperature, the assemblies (nanoparticles) should eventually dissolve; however, this is not the case due to the fact that polymer chains brought to a close proximity at elevated temperatures become hydrogen-bonded. In addition, hydrogen bonds strengthen upon cooling. Mainly carboxylic-carboxylate hydrogen bonds (COOH••• •COO-) are responsible for the irreversibility of the process and the stability of nanoparticles. Conclusions are supported by results from static and dynamic light scattering, FTIR spectroscopy, and cryo-TEM microscopy. Size of nanoparticles can be monitored during the growth and custom-tailored by tuning critical parameters, especially the degree of ionization, temperature, and time of heating. Nanoparticles are stable over long periods of time. They are stable in a broad range of salt concentrations, including physiological conditions, and possess a mild acceptable degree of polydispersity. © 2012 American Chemical Society.

Pavlik V.,Slovak University of Technology in Bratislava | Uzakova M.,Slovak Academy of Sciences
Construction and Building Materials | Year: 2016

The present study was undertaken to elucidate the influence of zeolite and metakaolin addition on the compressive strength, porosity, shrinkage, and frost resistance of lime mortars cured at different humidity conditions with or without access of carbon dioxide in a period up to 1 year. The changes in mineral composition of the binders were determined by X-ray diffraction and thermogravimetric analyses. It was found that pozzolans reduced shrinkage of fresh lime mortars. These admixtures positively affected compressive strength development and frost resistance of lime-pozzolan mortars when they were cured in the environment with the relative humidity of 100%. © 2015 Elsevier Ltd.

Battelli F.,Marche Polytechnic University | Feckan M.,Comenius University | Feckan M.,Slovak Academy of Sciences
Physica D: Nonlinear Phenomena | Year: 2012

We first study the problem of chaotic behaviour in time-perturbed discontinuous systems whose unperturbed part has a piecewise C1 homoclinic solution transversally crossing the discontinuity manifolds. We show that if a certain Melnikov function has a simple zero at some point, then the system has solutions that behave chaotically. The Melnikov function is explicitly constructed for two-dimensional systems and extends the usual Melnikov function for the smooth case. In the second part, we extend these results to sliding homoclinic bifurcations. We also mention some possibilities for further research. © 2011 Elsevier B.V. All rights reserved.

Pasteka R.,Comenius University | Karcol R.,Slovak Academy of Sciences | Kusnirak D.,Comenius University | Mojzes A.,Comenius University
Computers and Geosciences | Year: 2012

Downward continuation of potential fields is a powerful, but very unstable tool used in the processing and interpretation of geophysical data sets. Treatment of the instability problem has been realized by various authors in different ways. The Tikhonov regularization approach is one of the most robust. It is based on a low-pass filter derivation in the Fourier spectral domain, by means of a minimization problem solution. We highlight the most important characteristics from its theoretical background and present its realization in the form of a Matlab-based program. The optimum regularization parameter value is selected as a local minimum of constructed L p-norms functions-in the majority of cases, the C-norms give the best results. We demonstrate very good stabilizing properties of this method on several synthetic models and one real-world example from high-definition magnetometry. The main output of the proposed software solution is the estimation of the depth to source below the potential field measurement level. © 2012 Elsevier Ltd.

Krajci M.,Slovak Academy of Sciences | Hafner J.,University of Vienna
Physical Review B - Condensed Matter and Materials Physics | Year: 2013

The low-index surfaces of the AlPd compound crystallizing in the B20 (FeSi-type) structure have been investigated using ab initio density functional methods. The space group of the B20 structure is P213, with four threefold rotational axes along the 111 directions and three twofold screw axes along the 100 directions, but no inversion symmetry. The B20 structure exists in two enantiomorphic forms related by inversion. The termination of the structure perpendicular to the twofold screw axes is uniquely defined: The corrugated {100} surfaces are formed by the characteristic zigzag Al-Pd chains separated by shallow troughs. Perpendicular to the 210a directions the structure consists of slightly puckered planes containing Al and Pd in equal numbers. The {210} surfaces shows pseudo-fivefold symmetry. Their structure is shown to be closely related to that of the {110} surfaces of the B2 structure. Both the {100} and {210} surfaces undergo some structural relaxation, but no reconstruction changing their (1×1) periodicity. While perpendicular to the 100 and 210 directions only one surface termination is possible, perpendicular to the threefold 111 directions there are several possible surface terminations differing in structure and chemical composition. Because of the lack of inversion symmetry the threefold {111} surfaces have polar character. The (111) and (1̄1̄1̄) surfaces are not equivalent; the (111) surfaces of one enantiomorph are identical to the (1̄1̄1̄) surfaces of the other form (and vice versa). In both the (111) and (1̄1̄1̄) directions several surface terminations are possible. The formation of threefold surfaces has been studied by simulated cleavage experiments and by calculations of the surface energies of all possible terminations. Perpendicular to the 111 direction the lowest energy has been found for a bilayer with three Al atoms per surface cell in the upper layer and one Al and one Pd in the lower part. The preferable termination perpendicular to the 1̄1̄1 direction is more symmetric; it consists again of a bilayer with three Al atoms in the upper and three Pd atoms in the lower part. The surface energy of this termination further decreases if the Pd triplet is covered by additional Al atom. The calculated surface energies permit us to perform a Wulff construction of the equilibrium shape of AlPd crystallites. {100} and {210} facets together occupy 77% of the surface area in about equal proportion. The high anisotropy of the energy of the {111} surfaces results in the substantial difference of the surface areas of the opposite threefold facets. © 2013 American Physical Society.

Budaj J.,Slovak Academy of Sciences | Budaj J.,Australian National University
Astronomy and Astrophysics | Year: 2013

Context. An object with a very peculiar light curve was recently discovered using Kepler data. When this object was discovered, it was suggested that this object may be a transiting disintegrating extrasolar planet with a comet-like dusty tail. Aims. We aim to verify this model by modelling the light curve and put constraints on the geometry of the dust region and various dust properties. Methods. We modified the code SHELLSPEC, which is designed for modelling interacting binary stars to calculate the light curves of such planets. Mie absorption and scattering on spherical dust grains with realistic dust opacities, phase functions, and a finite radius of the source of the scattered light are taken into account Results. The light curve is reanalysed using long- and short-cadence Kepler observations from the first 14 quarters. The orbital period of the planet was improved. We prove that the peculiar light curve agrees with the idea of a planet with a comet-like tail. The light curve has a prominent pre-transit brightening and a less prominent post-transit brightening. Both are caused by the forward scattering and are a strong function of the particle size. This feature enabled us to estimate a typical particle size (radius) in the dust tail of about 0.1-1 micron. However, there is an indication that the particle size changes (decreases) along the tail. The dust density in the tail is a steep decreasing function of the distance from the planet, which indicates a significant tail destruction caused by the star-planet interaction. Several possible combinations of other dust properties are tabulated. We reveal interesting periodic long-term evolution of the tail on a time scale of about 1.3 years and also argue that the "planet" does not show a uniform behaviour, but may have at least two constituents. This exoplanet's tail evolution may find an analogy in the comet tail disconnection events caused by the magnetic/coronal activity of the Sun while the light curve with pre-transit brightening is analogous to the light curve of Ïμ Aur and AZ Cas with mid-eclipse brightening and forward scattering playing a significant role in such eclipsing systems. © ESO, 2013. © 2013 Author(s).

Mihalkovic M.,Slovak Academy of Sciences | Henley C.L.,Cornell University
Physical Review B - Condensed Matter and Materials Physics | Year: 2013

Using pair potentials fitted to an ab initio database, combined with replica-exchange simulated annealing, we show that the complex, quasicrystal-related Al11Ir4 compound contains a nonstandard version of the "pseudo-Mackay" icosahedral cluster, with nonicosahedral inner Al10Ir and/or Al9Ir clusters that exist in various orientations and account for partial occupancies in the reported structure. We found two different compositions with different orientationally ordered grounds, each doubling the (cubic) unit cell and each reached by a first-order thermal transition. One of these is metallic and the other is insulating. © 2013 American Physical Society.

Berek D.,Slovak Academy of Sciences
Journal of Separation Science | Year: 2016

Brief elucidation is presented of potential difficulties the researcher can face in the course of the molecular characterization of block copolymers with help of liquid chromatography under critical conditions. The impediments include the demanding identification of critical conditions, the limited area of applicable polymer molar mass, the high sensitivity of critical conditions toward minute changes in experimental conditions including changes in the interactivity of the column packing, extensive band broadening, limited sample recovery, pressure effects, detection problems, coelution of block copolymers with their noninteractive parent homopolymers, possible effect of the noninteracting chains of block copolymers on the behavior of the interacting blocks, and role of preferential solvation of macromolecules in mixed solvents. These matters may complicate proper data evaluation and challenge the exactness of results obtained. Special attention is paid to the so far neglected phenomena of preferential solvation, which may affect not only detection of block copolymers but also their retention. The latter occurrence is demonstrated by the behavior of both poly(methyl methacrylate)s eluted from bare silica gel in a mixed eluent tetrahydrofuran plus toluene and polystyrenes eluted from silica gel C18 bonded phase with the mobile phase of tetrahydrofuran/n-hexane. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Hricovini M.,Slovak Academy of Sciences
Journal of Physical Chemistry B | Year: 2015

High-resolution NMR and density functional theory (DFT) calculations have been applied to analysis of heparin pentasaccharide 3D structure in aqueous solution. The fully optimized molecular geometry of two pentasaccharide conformations (differing from each other in the form, one 1C4 and the other 2S0, of the sulfated iduronic acid residue) were obtained using the B3LYP/6-311+G(d,p) level of theory in the presence of solvent, the latter included as explicit water molecules. The presented approach enabled insight into variations of the bond lengths, bond angles, and torsion angles, formations of intra- and intermolecular hydrogen bonds, and ionic interactions in the two pentasaccharide conformations. A rather complex hydrogen bond network is formed, including inter-residue and intraresidue bonds between the NH group in the GlcN,3,6S with oxygens linked to C-2 at the IdoA2S residue and the glycosidic O-1 and the neighboring OSO3- group linked to C-3 in the same residue. On the other hand, because the first hydration shell is strongly influenced by strong ion-ion and ion-dipole interactions between sodium ions, sulfates, carboxylates, and -OH groups, ionic interactions play an important role in the stabilization of the 3D structure. The DFT-computed three-bond proton-proton coupling constants also showed that best agreement with experiment was obtained with a weighted average of 15:85 (1C4/2S0) of the sulfated iduronic acid forms indicating that the ratio is even more shifted toward the 2S0 form than previously supposed. The DFT-computed pentasaccharide conformation differs from the previously published data, with the main changes at the glycosidic linkages, namely, the 1 torsion angles and the ø3 angle. The comparison of the glycosidic linkage torsion angle values in solution with the antithrombin-pentasaccharide complex also indicates that the pentasaccharide conformation changes upon binding to antithrombin III. The data supports the assumption that the protein selects the more populated 2S0 conformer of heparin pentasaccharide and, consequently, the binding process of heparin pentasaccharide with antithrombin III is energetically more favorable than formerly expected. © 2015 American Chemical Society.

Jiraskova G.,Slovak Academy of Sciences
Lecture Notes in Computer Science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics) | Year: 2012

The paper shows that the tight bound for the conversion of alternating finite automata into nondeterministic finite automata with a single initial state is 2 n + 1. This solves an open problem stated by Fellah et al. (Intern. J. Computer Math. 35, 1990, 117-132). Then we examine the complexity of basic operations on languages represented by boolean and alternating finite automata. We get tight bounds for intersection and union, and for concatenation and reversal of languages represented by boolean automata. In the case of star, and of concatenation and reversal of AFA languages, our upper and lower bounds differ by one. © 2012 Springer-Verlag.

Stano P.,University of Arizona | Stano P.,Slovak Academy of Sciences | Jacquod P.,University of Arizona
Physical Review Letters | Year: 2011

Recent theoretical investigations have shown that spin currents can be generated by passing electric currents through spin-orbit coupled mesoscopic systems. Measuring these spin currents has, however, not been achieved to date. We show how mesoscopic spin currents in lateral heterostructures can be measured with a single-channel voltage probe. In the presence of a spin current, the charge current Iqpc through the quantum point contact connecting the probe is odd in an externally applied Zeeman field B, while it is even in the absence of spin current. Furthermore, the zero-field derivative BIqpc is proportional to the magnitude of the spin current, with a proportionality coefficient that can be determined in an independent measurement. We confirm these findings numerically. © 2011 American Physical Society.

Kocifaj M.,Slovak Academy of Sciences
Monthly Notices of the Royal Astronomical Society | Year: 2010

Spectral features of the night sky are simulated under cloudless conditions. Numerical runs show that spectral composition of the diffuse light changes over the whole sky and sky radiances quickly respond to altering aerosol characteristics, such as the asymmetry parameter, single scattering albedo and total optical thickness. The general trend is a steep decrease of diffuse irradiance with a distance from the city centre. Powerstar HQI-NDL lamps produce more light at short wavelengths, thus implying the higher levels of light pollution. The red light may markedly contribute to the obtrusive light if Vialox NAV-4Y lamps are considered as a prevailing source of light in the model town. In a non-turbid atmosphere, the minimum radiance is notoriously observed close to the zenith. As aerosol loading increases, the minimum radiance is shifted to larger zenith angles at the opposite side of the light source. Obtained results may serve as corrections to spectrophotometry data, as the light pollution can be easily calculated for any sky element and for any spectral band. © 2010 The Author. Journal compilation © 2010 RAS.

Solin L.,Slovak Academy of Sciences
International Journal of River Basin Management | Year: 2015

The exclusive application of the engineering approach to flood defence is a matter of increasing disapproval. This has led to a new paradigm in flood management – the integrated management of flood risk. The change from engineering-based flood protection to the integrated management of flood risk is comparatively slow and has varied in different countries. In Slovakia, the engineering approach enjoys a strong tradition. Recently, the parliament and the government of the Slovak Republic (SR) approved documents which establish new legal and operational frameworks for flood defence in the SR. The aim of this paper is to analyse these documents regarding the concept of integrated flood risk management. The analysis shows that flood protection continues to be based on the traditional engineering approach, which reduces flooding by technical structures. How integrated flood risk assessment and management can eliminate the consequences of engineering flood management is presented through two approaches to preliminary flood risk assessment. © 2015 International Association for Hydro-Environment Engineering and Research.

Hrobarik P.,TU Berlin | Hrobarik P.,Slovak Academy of Sciences | Hrobarikova V.,TU Berlin | Greif A.H.,TU Berlin | Kaupp M.,TU Berlin
Angewandte Chemie - International Edition | Year: 2012

Looking in the right (NMR) ballpark: The 13C shifts of carbon atoms Ï-bonded to uranium(VI) centers, and in particular the 1H shifts of U VI bound hydride ligands, are predicted to be at unprecedentedly high frequencies (see picture), as a result of unexpectedly large spin-orbit effects. Based on relativistic quantum-chemical calculations, the right spectral ranges are suggested, which may allow identification of such compounds. Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Bujdak J.,Comenius University | Bujdak J.,Slovak Academy of Sciences
Journal of Physical Chemistry C | Year: 2014

The formation of layer-by-layer (LBL) assemblies is a simple procedure, suitable for the construction of thin films with well-defined structures and compositions. LBL assemblies based on layered silicates, cationic organic dyes, and polycationic electrolyte were investigated by absorption and fluorescence spectroscopies. The formations of two simple films were investigated: one film bearing a laser dye, oxazine 1, and the second based on J-aggregates of pseudoisocyanine. A detailed study based on chemometric methods (principal component analysis, multivariate curve resolution-alternating least squares) confirmed the very complex nature of the LBL assembly formation. During the assembly deposition, the outer surface with the adsorbed dye often exhibited significant changes upon the formation of a new layer. These changes mainly included a partial desorption of the dye and structural rearrangement of the adsorbed dye species, including molecular aggregation. A complex film composed of alternating layers of the two dyes was made mainly for the purpose of investigating photophysical phenomena, such as fluorescence quenching and intermolecular resonance energy transfer. The results obtained can be useful for further studies leading to the development of functional materials based on photoactive dyes, inorganic layered carriers, and polyelectrolytes. © 2014 American Chemical Society.

Zelenka J.,Slovak Academy of Sciences
INES 2010 - 14th International Conference on Intelligent Engineering Systems, Proceedings | Year: 2010

This article refers to possibility of utilization of modeling of a manufacturing system sense as a discrete event system by the optimization of a job schedule. Using software tools we can create a model, which allows simulation of system behaviour at varying parameters. The example of the manufacturing system model created by the SimEvents toolbox of software tools Matlab is illustrated. © 2010 IEEE.

Sirotkin A.V.,Animal Production Research Center | Sirotkin A.V.,Constantine the Philosopher University | Laukova M.,Slovak Academy of Sciences | Ovcharenko D.,Altogen Biosystems | And 2 more authors.
Journal of Cellular Physiology | Year: 2010

Previous studies have shown that microRNAs (miRNAs) can control steroidogenesis in cultured granulosa cells. In this study we wanted to determine if miRNAs can also affect proliferation and apoptosis in human ovarian cells. The effect of transfection of cultured primary ovarian granulosa cells with 80 different constructs encoding human pre-miRNAs on the expression of the proliferation marker, PCNA, and the apoptosis marker, Bax was evaluated by immunocytochemistry. Eleven out of 80 tested miRNA constructs resulted in stimulation, and 53 miRNAs inhibited expression of PCNA. Furthermore, 11 of the 80 miRNAs tested promoted accumulation of Bax, while 46 miRNAs caused a reduction in Bax in human ovarian cells. In addition, two selected antisense constructs that block the corresponding miRNAs mir-15a and mir-188 were evaluated for their effects on expression of PCNA. An antisense construct inhibiting mir-15a (which precursor suppressed PCNA) increased PCNA, whereas an antisense construct for mir-188 (which precursor did not change PCNA) did not affect PCNA expression. Verification of effects of selected pre-mir-10a, mir-105, and mir-182 by using other markers of proliferation (cyclin B1) and apoptosis (TdT and caspase 3) confirmed specificity of miRNAs effects on these processes. This is the first direct demonstration of the involvement of miRNAs in controlling both proliferation and apoptosis by ovarian granulose cells, as well as the identification of miRNAs promoting and suppressing these processes utilizing a genome-wide miRNA screen. © 2009 Wiley-Liss, Inc.

Czachor H.,Polish Academy of Sciences | Doerr S.H.,University of Swansea | Lichner L.,Slovak Academy of Sciences
Journal of Hydrology | Year: 2010

Soil organic matter can modify the surface properties of the soil mineral phase by changing the surface tension of the mineral surfaces. This modifies the soil's solid-water contact angle, which in turn would be expected to affect its water retention curve (SWRC). Here we model the impact of differences in the soil pore-water contact angle on capillarity in non-cylindrical pores by accounting for their complex pore geometry. Key outcomes from the model include that (i) available methods for measuring the Young's wetting angle on soil samples are insufficient in representing the wetting angle in the soil pore space, (ii) the wetting branch of water retention curves is strongly affected by the soil pore-water contact angle, as manifest in the wetting behavior of water repellent soils, (iii) effects for the drying branch are minimal, indicating that both wettable and water repellent soils should behave similarly, and (vi) water retention is a feature not of only wettable soils, but also soils that are in a water repellent state. These results are tested experimentally by determining drying and wetting branches for (a) 'model soil' (quartz sands with four hydrophobization levels) and (b) five field soil samples with contrasting wettability, which were used with and without the removal of the soil organic matter. The experimental results support the theoretical predictions and indicate that small changes in wetting angle can cause switches between wettable and water repellent soil behavior. This may explain the common observation that relatively small changes in soil water content can cause substantial changes in soil wettability. © 2009 Elsevier B.V. All rights reserved.

Martinovic L.,Slovak Academy of Sciences
Acta Physica Polonica B, Proceedings Supplement | Year: 2013

Massless QED (1+1) - the Schwinger model - is studied in a covariant gauge. The main new ingredient is an operator solution of the Dirac equation expressed directly in terms of the fields present in the Lagrangian. This allows us to study in detail residual symmetry of the covariant gauge. For comparison, we analyze first an analogous solution in the Thirring-Wess model and its implication for the axial anomaly arising from the necessity to correctly define products of fermion operators via point-splitting. In the Schwinger model, one has to define the currents in a gauge-invariant (GI) way. Certain problems with their usual derivation are identified, that obscure the origin of the massive gauge boson. We show how to define the truly GI interacting currents, reformulate the theory in a finite volume and clarify role of the gauge zero mode in the axial anomaly and in the Schwinger mechanism. A transformation to the Coulomb gauge representation is suggested along with ideas about how to correctly obtain other properties of the model.

Mravec B.,Comenius University | Mravec B.,Slovak Academy of Sciences
Autonomic Neuroscience: Basic and Clinical | Year: 2010

The initiation and progression of ischemic and hemorrhagic stroke are the result of a complex cascade of processes that determine both the extent of the lesion and long-term outcome. Several of these processes, including peripheral inflammation, neuroinflammation, and neuroplasticity are influenced by the activity of the afferent as well as efferent pathways of the vagus nerve. It was shown that vagus nerve stimulation significantly reduces the extent of stroke-induced lesion of brain parenchyma. However, the mechanisms of beneficial effect of increased vagal activity on pathological processes related to stroke remains largely unclear. The aim of this article is to describe the role of afferent and efferent vagal pathways in the mechanisms that influence the initiation of stroke as well as its detrimental effects. © 2010 Elsevier B.V.

Takacs S.,Slovak Academy of Sciences
Cryogenics | Year: 2015

The resistivity of the normal region between neighboring and opposite superconducting stripes/strands/filaments in twisted structures should be large enough to obtain the coupling losses at acceptable level. The stability of such structures can be then very low, as the individual superconductors are more or less electrically insulated. In such structures, any electromagnetic perturbations or spatial inhomogeneities can be detrimental for the conductor and eventually for the whole design. Concentrating mainly on helically wound striated coated conductors, we show that placing some normal sheets on the superconductor tapes without increasing the coupling losses considerably can enhance the electromagnetic coupling. The results may be extended also to similar superconducting structures with not very high coupling losses, but requiring better stability, because current sharing between superconducting parts is necessary for electromagnetic stability of longer conductors. © 2014 Elsevier Ltd. All rights reserved.

Benus S.,Constantine the Philosopher University | Benus S.,Slovak Academy of Sciences
Cognitive Computation | Year: 2014

Speech entrainment is the tendency of interlocutors to become similar to each other during spoken interaction. Entrainment is a natural component of the cognitive system underlying communication, and the alignment of cognitive (para)linguistic representations between interlocutors is one way of conceptualizing it. Speech entrainment also plays an important social role, since humans perceive people who entrain to their speaking style as more socially attractive and likeable, more competent and intimate, and conversations with such partners as more successful. Furthermore, dis-entrainment might signal an increase in social distance and a negative attitude towards the interlocutor. Importantly for social robotics, humans also entrain to computer systems, and implementing this idea has brought improvements in several domains of human–machine interaction. This paper provides a targeted overview of advances in speech entrainment and argues that entrainment should be exploited in applications in which communication between humans and robots uses speech, as it opens up possibilities for developing and controlling social relations such as likeability and dominance and makes the applications more efficient. © 2014, Springer Science+Business Media New York.

Mesiarova-Zemankova A.,Slovak Academy of Sciences
Information Sciences | Year: 2016

The continuous, conditionally cancellative t-subnorms that posses a continuous, additive generator are discussed. Conditions for a continuous, conditionally cancellative t-subnorm to have a continuous, additive generator are described. Constructions of corresponding additive generators are also shown. © 2016 Published by Elsevier Inc.

Veselsky M.,Slovak Academy of Sciences
Journal of Computational Biology | Year: 2012

A simple method, inspired by procedures used in the physics of nuclear multi-fragmentation, allows for establishing order of precedence and age of pairs of haplotypes separated by one mutation. For both haplotypes of the pair, searches for existing haplotypes, differing by increasing number of mutations, are carried out using a database. The resulting ratios of frequencies of haplotypes, found at given mutation distances, are compared to calculated probability ratios. The order of precedence and age of the pair of haplotypes can be deduced when the resulting ratios follow a hyperbolic dependence. The method can be used with relatively small and not necessarily complete samples, using publicly accessible databases. © Copyright 2012, Mary Ann Liebert, Inc. 2012.

Zamocky M.,University of Natural Resources and Life Sciences, Vienna | Zamocky M.,Slovak Academy of Sciences | Gasselhuber B.,University of Natural Resources and Life Sciences, Vienna | Furtmuller P.G.,University of Natural Resources and Life Sciences, Vienna | Obinger C.,University of Natural Resources and Life Sciences, Vienna
Cellular and Molecular Life Sciences | Year: 2014

Heme peroxidases and catalases are key enzymes of hydrogen peroxide metabolism and signaling. Here, the reconstruction of the molecular evolution of the peroxidase-catalase superfamily (annotated in pfam as PF00141) based on experimentally verified as well as numerous newly available genomic sequences is presented. The robust phylogenetic tree of this large enzyme superfamily was obtained from 490 full-length protein sequences. Besides already well-known families of heme b peroxidases arranged in three main structural classes, completely new (hybrid type) peroxidase families are described being located at the border of these classes as well as forming (so far missing) links between them. Hybrid-type A peroxidases represent a minor eukaryotic subfamily from Excavates, Stramenopiles and Rhizaria sharing enzymatic and structural features of ascorbate and cytochrome c peroxidases. Hybrid-type B peroxidases are shown to be spread exclusively among various fungi and evolved in parallel with peroxidases in land plants. In some ascomycetous hybrid-type B peroxidases, the peroxidase domain is fused to a carbohydrate binding (WSC) domain. Both here described hybrid-type peroxidase families represent important turning points in the complex evolution of the whole peroxidase-catalase superfamily. We present and discuss their phylogeny, sequence signatures and putative biological function. © 2014 The Author(s).

Filip P.,Slovak Academy of Sciences
Journal of Physics: Conference Series | Year: 2016

The influence of static magnetic field on decays φ (1020) KK, ϒ (4s)→ BB, and Σ±∗ → π± is discussed. In particular, we estimate how much the ratio of decay widths Γ(K+K-)/Γ(K0K0) and Γ(B+B-)/Γ(B0B0) can be modified by magnetic fields of strength B ≈ 1014 T created in relativistic collisions of heavy nuclei at LHC and RHIC colliders. Due to interaction of charged K and B mesons with the magnetic field, branching ratios for K+K- and B+B- decays of φ (1020) and ϒ (4s) completely closed. We study also the influence of magnetic field on strong decay Σ±∗ (1385) → + π±.

Hricovini M.,Slovak Academy of Sciences
Journal of Physical Chemistry B | Year: 2011

Density functional theory (DFT) has been used to analyze structure and NMR spin-spin coupling constants in heparin disaccharide. Both B3LYP/6-311++G* and M05-2X/6-311++G* methods have been used for optimization of disaccharide geometry. Solvent effect was treated by use of explicit water molecules. Solvent-caused variations of DFT-computed indirect one-bond proton-carbon coupling constants up to 17 Hz between isolated and solvated states, however, had a limited influence upon magnitudes of proton-proton spin-spin coupling constants. Interatomic distances and bond and torsion angles indicated that the structure of the 2-O-sulfated iduronic acid residue affected the geometry of the N,6-sulfated glucosamine residue. Optimized disaccharide geometry showed that the change of counterion (Ca2+ instead of Na+) influenced geometry of pyranose rings and the glycosidic linkage conformation. DFT-computed three-bond proton-proton spin-spin coupling constants agreed well with published experimental data and indicated that the population of the 1C4 chair form of the 2-O-sulfated iduronic acid residue increased in the presence of Ca2+ ions compared to the presence of Na+ ions. Analysis also showed that the Fermi contact term was not always dominant and that paramagnetic and diamagnetic contributions considerably influenced magnitudes of proton-proton spin-spin coupling constants. © 2011 American Chemical Society.

Neurofibrillary degeneration and neuronal loss represent key pathological hallmarks of Alzheimer's disease (AD). It has been demonstrated that the decrease of total neuronal numbers correlates with the presence of neurofibrillary degeneration in AD brain. In order to unravel the mechanism leading to the cell death in AD, we developed a stably transfected human neuroblastoma cellular model with doxycycline-regulatable expression of AD truncated tau protein (AT tau, 151-391 4R). Cells expressing the longest tau isoform (Tau 40) were used as a control. We found that more than 80% of the total amount of AT tau and Tau 40 were phosphorylated. Strikingly, both AT tau and Tau 40 reduced the metabolic activity of the cells in a time-dependent manner (p < 0.0001) suggesting that tau overexpression slows down cell proliferation. However, AT tau showed significantly higher toxicity than Tau 40 (p < 0.0001), which indicates that truncation leads to a toxic gain of function. The analysis of the type of the cell death revealed the characteristic features of apoptosis such as cell shrinkage, nuclear, and DNA fragmentation. However, we did not find either the activation of executive caspase (caspase-3) or the caspase cleavage products (PARP and fodrin). These results show that posttranslationally modified truncated tau protein induces caspase-3-independent apoptosis-like programmed cell death, a phenomenon we term tauoptosis.

Cacanyiova S.,Slovak Academy of Sciences
Current Pharmaceutical Biotechnology | Year: 2011

Nitric oxide (NO) participates in the control of the cardiovascular system where two constitutive isoforms of NO-synthase were discovered: endothelial and neuronal. Both isoforms were observed in various cells, however, endothelial NO-synthase is predominantly present in the endothelium. Injury of the endothelium disturbs the balance between vasodilation and vasoconstriction and triggers different pathological alterations. In addition, whereas the intact endothelium protects vascular smooth muscle from oxidative attack, intervention in the vascular wall integrity increases the concentration of vascular superoxides, thus disturbing the effects of NO. To preserve NO-mediated vasorelaxation, different reserve mechanisms have developed. In case of damage of some endothelial receptor type, vasodilation could be ensured by activation of some other type of the present receptors. Moreover, morphological evidence demonstrated that both isoforms of NO-synthase were expressed also in smooth muscle cells and functional studies revealed that different pathological interventions in endothelial function (such as oxidative stress or hypertension) were associated with NO generation in the vascular media. In this case, the generation of NO by vascular smooth muscle may represent a physiologically relevant compensation of endothelial NO deficiency. Whereas long-term inhibition of endothelial NO-synthase resulted in an unequivocal pattern of cardiovascular changes, inhibition of neuronal NO-synthase led to opposite effects, suggesting a specific position of neuronal NO-synthase in the regulation of cardiovascular tone. The specificity of endothelial or neuronal NO function seems to be related to a particular circulatory area and it is presumably determined by mutual interactions with other regulatory systems (sympathoadrenergic, renin-angiotensin, etc.). © 2011 Bentham Science Publishers.

Butka P.,Technical University of Kosice | Pocs J.,Slovak Academy of Sciences
Computing and Informatics | Year: 2013

Robert Fuller We provide a generalization of one-sided (crisp-fuzzy) concept lattices, based on Galois connections. Our approach allows analysis of object-attribute models with different structures for truth values of attributes. Moreover, we prove that this method of creating one-sided concept lattices is the most general one, i.e., with respect to the set of admissible formal contexts, it produces all Galois connections between power sets and the products of complete lattices. Some possible applications of this approach are also included.

Ramaseshadri P.,Monsanto Corporation | Farkas R.,Slovak Academy of Sciences | Palli S.R.,University of Kentucky
Advances in Insect Physiology | Year: 2012

Insect juvenile hormones (JHs) are important regulators of development and reproduction. Perturbation in the homeostasis at inappropriate times in the various developmental and reproductive stages of an insect, which normally requires controlled release and metabolism of this and other hormones, results in abnormal development or lethal consequences. Such deliberate consequences have been possible by the discovery and use of Juvenile Hormone Analogs (JHAs), the synthetic chemicals that mimic JH action, which have also been utilised as insecticides for several decades. With the availability of molecular tools and improvement in pharmacophore analyses in the recent years, there has been considerable advancement in the understanding of the mode of action of JHAs and development of methods for discovery of novel JHAs. Although there is limited use of JHAs for insect pest control, the list of new insect species susceptible to these compounds has been expanding revealing the potential for future use of this class of insecticides. The relatively fewer effects of JHAs on non-target insects and animals and favourable environmental fate of these compounds make them attractive insecticides for inclusion in integrated pest management programmes. In this review, we provide a comprehensive overview of JHAs, as endocrinological and insecticidal tools covering all the relevant research topics on JHAs research during the past three decades. © 2012 Elsevier Ltd.

Orvosova M.,Slovak Museum of Nature Protection and Speleology | Deininger M.,University of Heidelberg | Milovsky R.,Slovak Academy of Sciences
Boreas | Year: 2014

Coarse crystalline cryogenic cave carbonate (CCC) forms during the slow freezing of standing water pools and represents indirect proof of freezing temperature in the past. The dating by U-series of CCC deposits from nine caves in the Western Carpathians Mountains of Slovakia suggests that freezing conditions, and possible permafrost conditions, occurred during the Last Permafrost Maximum (LPM, c.20-18 ka BP). The CCC deposits occur in caves at elevations of between 800 and 1800ma.s.l. They point to widespread alpine permafrost, the lower limit of discontinuous/sporadic permafrost being approximately 800ma.s.l. The thickness of permafrost probably varied between 30 and 180m. In the Vysoké Tatry Mountains at altitudes of ~1800ma.s.l., one occurrence of CCC suggests that subzero temperatures may have penetrated to a depth of over 285m. © 2013 The Boreas Collegium.

Brtko J.,Slovak Academy of Sciences | Dvorak Z.,Palacky University
Current Drug Metabolism | Year: 2011

Retinoic acid receptors (RARs), retinoid X receptors (RXRs) and thyroid hormone receptors (TRs) are nuclear receptors that are crucial transcriptional regulators of many cellular processes such as differentiation, development, apoptosis, carbohydrate and lipid metabolism, homeostasis etc. In addition, RXRs are common heterodimerization partners for several receptors including vitamin D receptor, pregnane X receptor (PXR), constitutive androstane receptor (CAR) etc. In the course of 90s', PXR and CAR were discovered as key xenosensors regulating drug-metabolizing enzymes. Since there exist various cross-talks between cell signaling pathways, this was not surprising that RXRs, RARs and TRs were identified as regulators of human drug-metabolizing cytochromes P450 and cytochromes P450 involved in metabolism of endogenous compounds. Hence, a link between regulation of xenobiotic metabolizing enzymes and regulatory pathways of intermediary metabolism was established. Additionally, several drug-metabolizing enzymes are involved in metabolism of retinoids, rexinoids and thyroid hormones. In the current paper, we summarize the knowledge on the role of RARs, RXRs and TRs in the regulation of drug metabolizing cytochromes P450, and vice versa on the role of P450s in homeostasis of retinoids, rexinoids and thyroid hormone. © 2011 Bentham Science Publishers Ltd.

Britanak V.,Slovak Academy of Sciences
IEEE Transactions on Signal Processing | Year: 2012

A new recursive fast radix-2 algorithm for an efficient computation of the modulated complex lapped transform (MCLT) is presented. Based on a new proposed alternative recursive sparse matrix factorization for the MDCT (modified discrete cosine transform) matrix and a relation between the MDCT and the MDST (modified discrete sine transform), firstly a new recursive fast radix-2 MDST algorithm is derived. The corresponding fast MDCT and MDST computational structures are regular and complementary to each other. Consequently, this fact enables us by their composition to construct a fast MCLT computational structure representing the fast recursive radix-2 MCLT algorithm. The fast MCLT computational structure is regular and all its stages may be realized in parallel. Combining the proposed fast radix-2 MCLT algorithm with an existing generalized fast mixed-radix MDCT algorithm defined for the composite lengths N=2× qm,m ≥ 2, where q is an odd positive integer, we can compute the MCLT for the composite lengths N=2n × q m,n,m ≥ 2, thus supporting a wider range of transform sizes compared to existing fast MCLT algorithms. © 1991-2012 IEEE.

Biely P.,Slovak Academy of Sciences
Biotechnology Advances | Year: 2012

Several plant polysaccharides are partially esterified with acetic acid. One of the roles of this modification is protection of plant cell walls against invading microorganisms. Acetylation of glycosyl residues of polysaccharides prevents hydrolysis of their glycosidic linkages by the corresponding glycoside hydrolases. In this way the acetylation also represents an obstacle of enzymatic saccharification of plant hemicelluloses to fermentable sugars which appears to be a hot topic of current research. We can eliminate this obstacle by alkaline extraction or pretreatment leading to saponification of ester linkages. However, this task has been accomplished in a different way in the nature. The acetyl groups became targets of microbial carbohydrate esterases that evolved to overcome the complexity of the plant cell walls and that cooperate with glycoside hydrolases in plant polysaccharide degradation. This article concentrates on enzymes deacetylating plant hemicelluloses excluding pectin. They are currently grouped in at least 8 families, specifically in CE families 1-7 and 16, originally assigned as acetylxylan esterases, the enzymes acting on hardwood acetyl glucuronoxylan and its fragments generated by endo-β-1, 4-xylanases. There are esterases deacetylating softwood galactoglucomannan, but they have not been classified yet. The enzymes present in CE families 1-7 differ in structure and substrate and positional specificity. There are families behaving as endo-type and exo-type deacetylates, i.e. esterases deacetylating internal sugar residues of partially acetylated polysaccharides and also esterases deacetylating non-reducing end sugar residues in oligosaccharides. With one exception, the enzymes of all mentioned CE families belong to serine type esterases. CE family 4 harbors enzymes that are metal-dependent aspartic esterases. Three-dimensional structures have been solved for members of the first seven CE families, however, there is still insufficient knowledge about their substrate specificity and real physiological role. Current knowledge on catalytic properties of the selected families of CEs is summarized in this review. Some of the families are emerging also as new biocatalysts for regioselective acylation and deacylation of carbohydrates. © 2012 Elsevier Inc.

Wang J.,Guizhou University | Zhou Y.,Xiangtan University | Feckan M.,Comenius University | Feckan M.,Slovak Academy of Sciences
Nonlinear Dynamics | Year: 2013

In this paper, a generalized Darbo's fixedpoint theorem associated with Hausdorff measure of noncompactness is established. Then we apply this new variant fixed-point theorem to study some fractional differential equations in Banach spaces via the technique of measure of noncompactness. Many novel existence and uniqueness results for solutions are obtained under the more general conditions. © Springer Science+Business Media B.V. 2012.