770 research outputs found

    Cardiovascular effects of an arginase II selective inhibitor

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    For the first time in vitro experiments there were studied the inhibitory activity and safety of potential molecules arginase II selective inhibitors from the group of norleucine derivatives. Also first the substance under the code ZB49-0010C from the group of norleucine derivatives showed the greatest selectivity and inhibitory activity against arginase II in experiments in vitro. However, this substance in vivo exerts dose-dependent hypotensive action and cardioprotective and endothelial protective effects on the L-NAME induced and homocysteine-induced endothelial dysfunction (ED), which are most pronounced at a dose of 10 mg/kg in intragastric administratio

    Ion channeling in CuInSe2 single crystals

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    CuInSe2 single crystals are studied by the Rutherford Backscattering of 2 MeV helium ions involving axial channeling along the 〈2 2 1〉 direction of the chalcopyrite lattice. Experimental values of the critical angle and normalized minimum yield are measured and compared with theory. The concentration of point defects separately in the Cu, In, and Se sublattices, determined from the comparison of experimental and theoretical minimum yields, are estimated as 4.7 × 1020, 1.0 × 1020, and 5.7 × 1020 cm-3, respectively. © 2013 Elsevier B.V. All rights reserved

    Optical properties of high quality Cu2ZnSnSe4 thin films

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    Cu2ZnSnSe4 thin films, fabricated on bare or molybdenum coated glass substrates by magnetron sputtering and selenisation, were studied by a range of techniques. Photoluminescence spectra reveal an excitonic peak and two phonon replicas of a donor-acceptor pair (DAP) recombination. Its acceptor and donor ionisation energies are 27 and 7 meV, respectively. This demonstrates that high-quality Cu2ZnSnSe4 thin films can be fabricated. An experimental value for the longitudinal optical phonon energy of 28 meV was estimated. The band gap energy of 1.01 eV at room temperature was determined using optical absorption spectr

    Correction of retinal ischemia/reperfusion by 3-(1H-benzimidazol-2-il)-1,2,2-trimethyl cyclopentancarbonic acid in experiment

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    Results of ocular fundus studies revealed the most pronounced protective effects of 3-(1Hbenzimidazol-2-il)-1,2,2-trimethyl cyclopentancarbonic acid in a dose 50 mg/kg on the model of retinal ischemiareperfusion in Wistar rats, which is reflected in the restoration of the optic disc. Correction of retinal ischemiareperfusion by 3-(1H-benzimidazol-2-il)-1,2,2-trimethyl cyclopentancarbonic acid in a dose 50 mg/kg leads to higher values of the coefficient b/a of electroretinography after 72 hours of reperfusion compared to the group with pathology correction by the same drug in a dose 10 mg/kg, which indicates the restoration of the electrophysiological state of the retin

    Resonant photoemission spectroscopy of Cu(InGa)Se2 materials for solar cells

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    The electron structure of CuIn1 - x Ga x Se 2 single crystals is determined via resonant photoemis-sion and the main regularities of its transformation upon varying concentration x from 0 to 1 are established. The dependence of the shape of valence band spectra on the photon energy is studied. Integral photoemission intensities are shown to be determined by atomic photoionization cross sections. Processes of the direct and two-step creation of photoelectrons accompanying photoemission and the participation of internal states in the spectra of electrons from valence bands are studied. Two-hole final states in photoemission are obtained upon threshold excitation of the Cu 2p level. The strong interaction of holes leads to the multiplet splitting of these states. Partial densities of the components' states are determined using the energy dependence of atomic photoionization cross sections. © 2013 Allerton Press, Inc

    Investigation of the Structure and Properties of Coatings on Molybdenum Obtained in the Process of Low-Temperature Siliconizing in a Vibro-Boiling Bed

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    Образцы молибдена были подвергнуты низкотемпературному силицированию в виброкипящем слое в среде чистого кремния с использованием активатора NH4Cl при температурах 850, 900, 950 °C и выдержкой 120 мин. Проведены комплексные структурные исследования полученных покрытий методами РЭМ и РСФА. Рассчитаны константы скорости роста силицидного слоя MoSi2.Molybdenum samples were subjected to low-temperature siliconization in a vibrating-boiling pure silicon layer with NH4Cl activator at a temperature 850, 900, 950 °C with a holding time of 120 minutes. Complex structural studies of the obtained coatings were carried out and the growth rate constants of the MoSi2 layer were calculated.Авторы выражают благодарность научному руководителю — кандидату технических наук, доценту Н.И. Кардониной.The authors express their gratitude to the scientific supervisor — candidate of sciences in engineering, associate professor N.I. Kardoni

    Numerical and experimental studies of the carbon etching in EUV-induced plasma

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    We have used a combination of numerical modeling and experiments to study carbon etching in the presence of a hydrogen plasma. We model the evolution of a low density EUV-induced plasma during and after the EUV pulse to obtain the energy resolved ion fluxes from the plasma to the surface. By relating the computed ion fluxes to the experimentally observed etching rate at various pressures and ion energies, we show that at low pressure and energy, carbon etching is due to chemical sputtering, while at high pressure and energy a reactive ion etching process is likely to dominate

    A photoelectron spectroscopy study of the electronic structure evolution in CuInSe2-related compounds at changing copper content

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    Evolution of the valence-band structure at gradually increasing copper content has been analysed by x-ray photoelectron spectroscopy (XPS) in In2Se3, CuIn5Se8, CuIn3Se5, and CuInSe2 single crystals. A comparison of these spectra with calculated total and angular-momentum resolved density-of-states (DOS) revealed the main trends of this evolution. The formation of the theoretically predicted gap between the bonding and non-bonding states has been observed in both experimental XPS spectra and theoretical DOS

    Gaussian Mixture Models and Model Selection for [18F] Fluorodeoxyglucose Positron Emission Tomography Classification in Alzheimer’s Disease

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    We present a method to discover discriminative brain metabolism patterns in [18F] fluorodeoxyglucose positron emission tomography (PET) scans, facilitating the clinical diagnosis of Alzheimer’s disease. In the work, the term “pattern” stands for a certain brain region that characterizes a target group of patients and can be used for a classification as well as interpretation purposes. Thus, it can be understood as a so-called “region of interest (ROI)”. In the literature, an ROI is often found by a given brain atlas that defines a number of brain regions, which corresponds to an anatomical approach. The present work introduces a semi-data-driven approach that is based on learning the characteristics of the given data, given some prior anatomical knowledge. A Gaussian Mixture Model (GMM) and model selection are combined to return a clustering of voxels that may serve for the definition of ROIs. Experiments on both an in-house dataset and data of the Alzheimer’s Disease Neuroimaging Initiative (ADNI) suggest that the proposed approach arrives at a better diagnosis than a merely anatomical approach or conventional statistical hypothesis testing

    Use of L-arginine immobilised on activated carbon for pharmacological correction of endothelial disfunction

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    For the first time a complex of L-arginine sodium salt of sulfate of cellulose acetate on activated carbon. To investigate the processes of sorption-desorption of L-arginine in a model environmen
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