Je Purkinje University

Ústí nad Labem, Czech Republic

Je Purkinje University

Ústí nad Labem, Czech Republic
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Wu Q.,Huazhong Agricultural University | Dohnal V.,University of Hradec Kralove | Dohnal V.,Je Purkinje University | Huang L.,Huazhong Agricultural University | And 2 more authors.
Drug Metabolism Reviews | Year: 2010

Trichothecenes are a group of mycotoxins mainly produced by the fungi of Fusarium genus. Consumers are particularly concerned over the toxicity and food safety of trichothecenes and their metabolites from food-producing animals. The metabolism of T-2 toxin, deoxynivalenol (DON), nivalenol (NIV), fusarenon-X (FX), diacetoxyscirpenol (DAS), 3-acetyldeoxy-nivalenol (3-aDON), and 15-acetyldeoxynivalenol (15-aDON) in rodents, swine, ruminants, poultry, and humans are reviewed in this article. Metabolic pathways of these mycotoxins are very different. The major metabolic pathways of T-2 toxin in animals are hydrolysis, hydroxylation, de-epoxidation, and conjugation. After being transformed to HT-2 toxin, it undergoes further hydroxylation at C-3' to yield 3'-hydroxy-HT-2 toxin, which is considered as an activation pathway, whereas transformation from T-2 to T-2 tetraol is an inactivation pathway in animals. The typical metabolites of T-2 toxin in animals are HT-2 toxin, T-2 triol, T-2 tetraol, neosolaniol (NEO), 3'-hydroxy-HT-2, and 3'-hydroxy-T-2, whereas HT-2 toxin is the main metabolite in humans. De-epoxidation is an important pathway for detoxification in animals. De-epoxy products, DOM-1, and de-epoxy-NIV are the main metabolites of DON and NIV in most animals, respectively. However, the two metabolites are not found in humans. Deacetyl can occur rapidly on the acetyl derivatives, 3-aDON, 15-aDON, and FX. DAS is metabolized in animals to 15-monoacetoxyscirpenol (15-MAS) via C-4 deacetylation and then transformed to scirpentriol (SCP) via C-15 deacetylation. Finally, the epoxy is lost, yielding de-epoxy-SCP. De-epoxy-15-MAS is also the main metabolite of DAS. 15-MAS is the main metabolite in human skin. The review on the metabolism of trichothecenes will help one to well understand the fate of these toxins' future in animals and humans, as well as provide basic information for the risk assessment of them for food safety. © 2010 Informa UK Ltd.


Moucka F.,Je Purkinje University | Nezbeda I.,Je Purkinje University | Nezbeda I.,Czech Institute of Chemical Process Fundamentals
Fluid Phase Equilibria | Year: 2013

The multi-particle-move Monte Carlo methodology is implemented for Gibbs ensemble Monte Carlo (GEMC) simulations and applied to two recent Baranyai-Kiss polarizable models of water. In addition to obtaining and reporting the GEMC data for the considered models, attention is paid also to technical parts of simulations, particularly to the long-range corrections. A detailed analysis identifies the reasons for discrepancies found between the present results and those reported in literature. The problem lies in the application of incomplete long-range corrections in previous studies. It turns out that in fact both considered models are in better agreement with experiment than originally reported. © 2013 Elsevier B.V.


Gryndler M.,Je Purkinje University | Cerna L.,Academy of Sciences of the Czech Republic | Bukovska P.,Academy of Sciences of the Czech Republic | Hrselova H.,Academy of Sciences of the Czech Republic | Jansa J.,Academy of Sciences of the Czech Republic
Mycorrhiza | Year: 2014

Mycorrhizal fungi provide direct and functional interconnection of soil environment with their host plant roots. Colonization of non-host plants have occasionally been described, but its intensity and functional significance in complex plant communities remain generally unknown. Here, the abundance of ectomycorrhizal fungus Tuber aestivum was measured in the roots of host and non-host (non-ectomycorrhizal) plants in a naturally occurring T. aestivum colony using a quantitative PCR approach. The roots of non-host plant species found inside the brûlé area were extensively colonized by T. aestivum mycelium, although the levels were significantly lower than those found in host Carpinus betulus roots. However, fungal biomass concentration in the non-host roots was one to two orders of magnitude higher than that in the surrounding soil. This indicates existence of an important biotic interaction between T. aestivum mycelium and the non-host, mostly herbaceous plants. Roots, either host or non-host, thus probably constitute hot spots of T. aestivum activity in the soil ecosystem with as yet uncovered functional significance. © 2014, Springer-Verlag Berlin Heidelberg.


Vachata P.,Je Purkinje University | Petrovicky P.,Charles University | Sames M.,Je Purkinje University
Journal of Clinical Neuroscience | Year: 2010

Although many reports mention a "high jugular bulb" (HJB), it is often not clearly defined. We examined the relationship between the jugular bulb (JB) and the internal auditory canal (IAC) in 200 temporal bones on high resolution CT scans and alcohol-fixed skull bases of adults. The average distance (±standard deviation) between the IAC and the JB was 7.5 ± 2.3 mm (range, 1-16 mm). The JB was higher on the right side than its companion in 53.3% of patients (left side only in 22%; no side dominance in 23.7% of bases). When the JB reached or exceeded the floor of the IAC (16.5%), it was defined as a HJB; 61% of HJB were found in females. Bilateral HJB was found in 0.5% of patients. The HJB was not associated with a contralateral flat JB. Preoperative multiplanar high resolution CT reconstructions make the most detailed assessment of structural topography. © 2009 Elsevier Ltd. All rights reserved.


Kormunda M.,Je Purkinje University | Pavlik J.,Je Purkinje University
Vacuum | Year: 2011

The SnO2 gas sensors and catalytic surfaces are produced by different techniques with a wide range of dopants improving their selectivity and sensitivities. The surface topology is important because the active surface area can be enlarged dramatically by employing nanostructures. Many reported techniques for the tin oxide nanostructures preparation require fine powders or liquid precursors together with high temperatures above 500 °C. But the nanostructures can be formed by the RF off-axis magnetron sputtering technique at room temperature from a bulk target. The single target co-sputtering of SnO2 target with Fe inset was used to deposit SnO2 film doped by iron. The 400 nm diameter pillars were successfully deposited in controllable density on polished Si substrates at low pressure 0.3 Pa of argon and oxygen gas mixture. The pillars were not formatted at the beginning of deposition process but certain SnO2 film was required. The surface around the pillars was flat without any significant texture. The iron in form of the iron oxide was found to be the doping in deposited coatings when the stannic oxide was sub-stoichiometry with oxygen vacancies. © 2011 Elsevier Ltd. All rights reserved.


Boublik T.,Je Purkinje University
Fluid Phase Equilibria | Year: 2012

Two-dimensional systems, especially systems of hard disks, have been studied intensively during the last years both by simulation methods and theoretically; modified density functional theory has been applied most often. Recently, we have proposed an improved expression for the residual Helmholtz energy, ΔA, of the mixtures of 2D convex figures, which makes it possible to develop another, more simple " geometric" method. By differentiating ΔA with respect to the number of particles of type j, the chemical potential Δμ j might be obtained and consequently the logarithm of the radial distribution function expressed in terms of Δμ k of the considered pair of particles and the corresponding combined figure. The resulting equation is very simple, only two geometric quantities - figure areas and mean curvature integrals (mean radii) are to be evaluated. The used method is extremely simple and yields accurate prediction of the radial distribution functions of both the one- and multi-component systems in the most important interval of distances. © 2011 Elsevier B.V.


Skvor J.,Je Purkinje University | Nezbeda I.,Je Purkinje University | Nezbeda I.,Czech Institute of Chemical Process Fundamentals
Molecular Physics | Year: 2011

The question of a physical relevance (meaning) of the percolation line in simple supercritical fluids has been addressed using both extensive Monte Carlo simulations and accurate analytic equations of state. Thermodynamic and structural properties of two qualitatively different fluids, the Lennard-Jones (continuous model) and square-well fluid (stepwise model), have been studied in the vicinity of their percolation lines over a range of pressures in order to find potential changes which may take place when an infinite cluster is detected in the system. Two different criteria for the occurrence of an infinite cluster, physical and configurational criteria, have also been used to assess their effect on the observed properties. It is found that the lines of extremes of various response functions run close to the percolation lines. Accounting for uncertainties in the definition of bonds and determination of the percolation line one may conjecture that extremes in some response functions occur when crossing the percolation line. © 2011 Taylor & Francis.


Boublik T.,Je Purkinje University
Molecular Physics | Year: 2011

Knowledge of the structure of simple fluids in nano-tubes constitutes important information in many scientific and technical branches. Computer simulations and density functional theory (DFT) offer accurate but laborious results. We have proposed a simple analytical method to determine the background correlation function on the basis of the residual chemical potentials of a pair of interacting bodies and of the corresponding combined body. These potentials are obtained in terms of geometric quantities. In this paper we dealt with the combination rule for the geometric quantity Q; the harmonic mean rule was proposed and verified at low densities by calculating the third cross-virial coefficient, and by comparing calculated density profiles of the inhomogeneous systems of hard sphere-wall at higher densities. A slight improvement over the previous results were found. Next, we applied our analytic method to realistic systems of a simple molecule in the graphite cylindrical pore. Hydrogen (and carbon monoxide), interacting with carbon of the graphite via the modified LJ potential are considered and the density profile was determined taking into account only the soft-sphere interaction within Weeks-Chandler-Andersen approximation. The considered approach was found to yield a fair description of the realistic simple fluid-cylindrical pore system. © 2011 Taylor & Francis.


Boublik T.,Je Purkinje University
Molecular Physics | Year: 2011

An improved two-dimensional (2D) equation of state is proposed on the basis of an expression from scaled particle theory. For pure hard disks, the virial coefficients B 3-B 18 are determined and compared with their pseudo-experimental values. The 2D compressibility factor, Z, of pure hard disks is evaluated from the improved equation of state (IEOS) and compared with Z from Henderson's relation and with simulation data. Similarly, the Z values of mixtures of hard disks with diameter ratios σ 2/σ 1 = 1, 2, 3, 4, 5 and 10 and mole fractions x 1 = 0.5 and 0.25 were compared with the corresponding simulation data. Fair agreement was found in the case of the pure fluid as well as the studied mixtures. The third and fourth virial coefficients of three types of convex figures - hard ellipses, hard spherocylinders and rectangles - were determined from the IEOS and fair agreement with pseudo-experiment was found. The predictive capability of the considered IEOS was investigated for 2D hard prolate spherocylinders and systems of hard ellipses with three values of the aspect ratio, k = a/b, k = 2, 4 and 6 (where a and b denote the semi-axes of an ellipse). The compressibility factor of the 2D spherocylinders compared well with the MC data; in the case of hard ellipses, the description is fair for the isotropic phase. © 2011 Taylor & Francis.


Kormunda M.,Je Purkinje University | Pavlik J.,Je Purkinje University
Polymer Degradation and Stability | Year: 2010

The effects of low (2.5, 0.2 keV) energy reactive oxygen ion bombardment and argon ion bombardment on poly(ethylene terephthalate) thin film (PET) surface chemical composition were studied. PET films have a high potential as a material for biomedical and electrical industries. The source of ions was an ECR Ion Gun with settable acceleration voltages. PET films were sputtered by ion bombardment for variable process time and the modified films were investigated by in-situ X-ray Photoelectron Spectroscopy (XPS) and ex-situ Fourier transform infrared spectroscopy (FTIR). The significant changes in the chemical composition of surface layers were quantitatively studied by XPS. The ion bombardment scissions the chains in PET film surface layers. Selective sputtering of oxygen atoms from PET surface was observed when argon ion flux used. The 0.2 keV and 2.5 keV argon ion decreased O/C ratio from 0.37 to 0.25, 0.04 respectively. This phenomenon is responsible for the creation of carbon-rich up 96 at.% surface layer and the oxygen in ester bonds is detached first. The oxygen 2.5 keV ion bombardment had similar effect as argon ion bombardment; the ratio O/C was decreased. The ester bond was broken first. But oxygen 0.2 keV ion flux irradiation created an oxygen rich surface; the O/C ratio was in increased from 0.37 to 0.46. The changes in surface conductivity were investigated by shifts in C1s binding energy. Good agreement with atomic concentration of carbon in C-C bonds on the films surface was found. The FTIR analyses identified changes in chemical composition but with no obvious correlation to surface changes. Photons from the ion source irradiating the PET film during ion bombardment probably caused the observed changes in FTIR spectra. © 2010 Elsevier Ltd. All rights reserved.

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