705 research outputs found
Correction of retinal ischemia/reperfusion by 3-(1H-benzimidazol-2-il)-1,2,2-trimethyl cyclopentancarbonic acid in experiment
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
Ion channeling in CuInSe2 single crystals
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
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
Gaussian Mixture Models and Model Selection for [18F] Fluorodeoxyglucose Positron Emission Tomography Classification in Alzheimer’s Disease
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
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
The role of pharmacist in early phase clinical research
This article discusses the role of pharmacist in early phase clinical trials. Authors emphasize that in Russian phase I units pharmacists are rarely involved in clinical research activities. Probably the lack of regulatory documentation in this field is one of the main reasons. The opposite situation occurs abroad where pharmacist is key member of investigational team. This problem is particularly relevant because number of phase I studies in Russia steadily increases over the last years. Based on their practical experience authors describe the range of pharmacist functions and responsibilities when working in early phase research. Qualification requirements and skills of such specialist are pointed out as well. Due to the fact that not only number of trials but also number of phase I units increases (including private departments) the value of pharmacist in clinical research will grow
DANSSino: a pilot version of the DANSS neutrino detector
DANSSino is a reduced pilot version of a solid-state detector of reactor
antineutrinos (to be created within the DANSS project and installed under the
industrial 3 GW(th) reactor of the Kalinin Nuclear Power Plant -- KNPP).
Numerous tests performed at a distance of 11 m from the reactor core
demonstrate operability of the chosen design and reveal the main sources of the
background. In spite of its small size (20x20x100 ccm), the pilot detector
turned out to be quite sensitive to reactor antineutrinos, detecting about 70
IBD events per day with the signal-to-background ratio about unity.Comment: 16 pages, 11 figures, 3 tables. arXiv admin note: substantial text
overlap with arXiv:1304.369
Optical spectroscopy studies of Cu2ZnSnSe4 thin films
Cu2ZnSnSe4 thin films were synthesised by selenisation of magnetron sputtered metal precursors. The band gap determined from the absorption spectra increases from 1.01 eV at 300 K to 1.05 eV at 4.2 K. In lower quality films photoluminescence spectra show a broad, low intensity asymmetric band associated with a recombination of free electrons and holes localised on acceptors in the presence of spatial potential fluctuations. In high quality material the luminescence band becomes intense and narrow resolving two phonon replicas. Its shifts at changing excitation power suggest donor–acceptor pair recombination mechanisms. The proposed model involving two pairs of donors and acceptors is supported by the evolution of the band intensity and spectral position with temperature. Energy levels of the donors and acceptors are estimated using Arrhenius quenching analysis
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