55 research outputs found
Monitoring of mercury content in agroecosystems of the central Chernozem region of Russia
The paper considers the results of the local agroecological monitoring of the agroecosystems of the Belgorod region and the ecosystems of Yamskaya Steppe of the reserve “Belogorye
Traveling through potential energy landscapes of disordered materials: the activation-relaxation technique
A detailed description of the activation-relaxation technique (ART) is
presented. This method defines events in the configurational energy landscape
of disordered materials, such as a-Si, glasses and polymers, in a two-step
process: first, a configuration is activated from a local minimum to a nearby
saddle-point; next, the configuration is relaxed to a new minimum; this allows
for jumps over energy barriers much higher than what can be reached with
standard techniques. Such events can serve as basic steps in equilibrium and
kinetic Monte Carlo schemes.Comment: 7 pages, 2 postscript figure
Effect of Secondary Echo Signals in Spin-Systems with a Large Inhomogeneous Broadening of NMR Line
The possibility of comparatively simple and fast determination of
characteristic relaxation parameters T1, T2 and T3 for nuclear spin-systems
with strong Larmor and Rabi inhomogeneous broadenings of NMR lines using the
secondary echo signal effect was experimentally shown. Resides, this method
gives opportunity to obtain a valuable infomation on the inhomogeneous NMR
broadening which reflects the character of magnetic field microscopic
destribution in such systems, as example, multidomain magnetics and
superconductors.Comment: 12 pages, 5 figure
Atomic layering at the liquid silicon surface: a first- principles simulation
We simulate the liquid silicon surface with first-principles molecular
dynamics in a slab geometry. We find that the atom-density profile presents a
pronounced layering, similar to those observed in low-temperature liquid metals
like Ga and Hg. The depth-dependent pair correlation function shows that the
effect originates from directional bonding of Si atoms at the surface, and
propagates into the bulk. The layering has no major effects in the electronic
and dynamical properties of the system, that are very similar to those of bulk
liquid Si. To our knowledge, this is the first study of a liquid surface by
first-principles molecular dynamics.Comment: 4 pages, 4 figures, submitted to PR
Application of 3D Zernike descriptors to shape-based ligand similarity searching
Background: The identification of promising drug leads from a large database of compounds is an important step in the preliminary stages of drug design. Although shape is known to play a key role in the molecular recognition process, its application to virtual screening poses significant hurdles both in terms of the encoding scheme and speed. Results: In this study, we have examined the efficacy of the alignment independent three-dimensional Zernike descriptor (3DZD) for fast shape based similarity searching. Performance of this approach was compared with several other methods including the statistical moments based ultrafast shape recognition scheme (USR) and SIMCOMP, a graph matching algorithm that compares atom environments. Three benchmark datasets are used to thoroughly test the methods in terms of their ability for molecular classification, retrieval rate, and performance under the situation that simulates actual virtual screening tasks over a large pharmaceutical database. The 3DZD performed better than or comparable to the other methods examined, depending on the datasets and evaluation metrics used. Reasons for the success and the failure of the shape based methods for specific cases are investigated. Based on the results for the three datasets, general conclusions are drawn with regard to their efficiency and applicability
OPPORTUNITIES OF CORRECTION OF RHEOLOGICAL PROPERTIES OF BLOOD IN INTENSIVE THERAPY IN PATIENTS WITH PERITONITIS AND ACUTE BOWEL OBSTRUCTION
An analysis of efficacy of 1.5% reamberin solution usage was made in 80 patients for correction of blood rheological properties disorder in the case of peritonitis and bowel obstruction. It was established, that reamberin, which was administered in the dose of 500 ml after 12 hours of the beginning of intensive care during 48 hours, efficiently corrected the rheological disorders. It was because the erythron and reticulocyte production were activated, the hyposmolarity was removed, the intensity of free radical oxidation and peroxide oxidation of lipids was decreased and the antioxidant status was restored. This facilitated the hydrophily and erythrocyte volume decrease, the haemolysis reduction and qualitative gas exchange at the level of tissues
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