Endothelotropic activity of 4-hydroxy-3,5-di-tret-butylcinnamic acid in the conditions of experimental cerebral ischemia

The aim of the study was to evaluate the endothelioprotective activity of 4-hydroxy-3,5-di-tret-butylcinnamic acid in conditions of experimental cerebral ischemia. The brain ischemia was reproduced by the method of irreversible right-sided thermocoagulation of the middle cerebral artery. As comparative drugs, mexidol (30 mg/kg) and sulodexide (30 U/kg) were use

Analysis of functional condition of cardiorespiratory system of qualified and entrant weight lifters

This article provides data of the analysis of functional condition of cardio respiratory system of qualified and entrant weight lifter

Neuroprotective effect of L-carnitine. Focus on changing mitochondrial function

In this study, the neuroprotective effect of L-carnitine administered per os in a dose of 25 mg/kg-800 mg/kg was evaluated. The effects of L-carnitine on changes in mitochondrial function were also studie

Accumulation of aggregated alpha-synuclein in neural tissue structures in neurodegenerative diseases

A critical analysis of the literature on the structure and properties of alpha-synuclein under physiological and pathological conditions is presented, when the conformation of this protein changes, which contributes to its aggregation and changes in localization features in brain structures in such neurodegenerative diseases as Parkinson’s disease, dementia with Lewy bodies, multiple systemic atrophy and Alzheimer’s disease. It has been shown that the toxic effect of conformationally altered alpha-synuclein can indirectly affect the functions of neurons due to its interaction with neuroglial cells, primarily microglia and astrocytes, and can also modulate the aggregation and expression of other proteins that are functionally important for the development of neurodegeneration. Further study of the mechanisms of interaction of conformationally altered alphasynuclein with other proteins and clarification of the relationship between its accumulation in brain structures and neuronal dysfunction remains relevant for modern neurology. Literature search was carried out in the “PubMed” and “eLIBRARY” databases

Electrochemical oxygenation of diorganyldichlorosilanes: A novel route to generation of diorganylsilanones

Interaction of diorganyldichlorosilanes R2SiCl2 (R = Me, Et, Ph) with superoxide or peroxide anions, produced in situ by electroreduction of molecular oxygen, provides short-living diorganylsilanones R2Si=O. The latter undergo cyclization to give lower perorganylcyclosiloxanes (R2SiO)n, n = 3 or 4 and then insert to the molecules of these primary products to form higher cyclic oligomers. When the process is carried out in the presence of a reagent-trap for silanones (hexamethyldisiloxane, hexamethylcyclotrisiloxane), the products of insertion of diorganylsilanones into the molecule-traps (Me3Si(OSiR2)nOSiMe3 with n ≥ 1, and (Me2SiO)3(R2SiO)m with m ≥ 1, respectively) were obtained. © 2000 Elsevier Science B.V. All rights reserved

The effect of oxide precipitates on minority carrier lifetime in n-type silicon

Supersaturated levels of interstitial oxygen in Czochralski silicon can lead to the formation of oxide precipitates. Although beneficial from an internal gettering perspective, oxygen-related extended defects give rise to recombination which reduces minority carrier lifetime. The highest efficiency silicon solar cells are made from n-type substrates in which oxide precipitates can have a detrimental impact on cell efficiency. In order to quantify and to understand the mechanism of recombination in such materials, we correlate injection level-dependent minority carrier lifetime data measured with silicon nitride surface passivation with interstitial oxygen loss and precipitate concentration measurements in samples processed under substantially different conditions. We account for surface recombination, doping level, and precipitate morphology to present a generalised parameterisation of lifetime. The lifetime data are analysed in terms of recombination activity which is dependent on precipitate density or on the surface area of different morphologies of precipitates. Correlation of the lifetime data with interstitial oxygen loss data shows that the recombination activity is likely to be dependent on the precipitate surface area. We generalise our findings to estimate the impact of oxide precipitates with a given surface area on lifetime in both n-type and p-type silicon

How do methanol masers manage to appear in the youngest star vicinities and isolated molecular clumps?

General characteristics of methanol (CH3OH) maser emission are summarized. It is shown that methanol maser sources are concentrated in the spiral arms. Most of the methanol maser sources from the Perseus arm are associated with embedded stellar clusters and a considerable portion is situated close to compact HII regions. Almost 1/3 of the Perseus Arm sources lie at the edges of optically identified HII regions which means that massive star formation in the Perseus Arm is to a great extent triggered by local phenomena. A multiline analysis of the methanol masers allows us to determine the physical parameters in the regions of maser formation. Maser modelling shows that class II methanol masers can be pumped by the radiation of the warm dust as well as by free-free emission of a hypercompact region hcHII with a turnover frequency exceeding 100 GHz. Methanol masers of both classes can reside in the vicinity of hcHIIs. Modelling shows that periodic changes of maser fluxes can be reproduced by variations of the dust temperature by a few percent which may be caused by variations in the brightness of the central young stellar object reflecting the character of the accretion process. Sensitive observations have shown that the masers with low flux densities can still have considerable amplification factors. The analysis of class I maser surveys allows us to identify four distinct regimes that differ by the series of their brightest lines.Comment: 8 pages, 4 figures, invited presentation at IAU242 "Astrophysical Masers and their environments

Study of dose-dependent actoprotective effect of ATACL on physical performancend psychoemotional status of animals under exhausting exercise

The aim of the study was to investigate the dose-dependent actoprotective effect of ATACL on physical performance and psychoemotional status of animals under conditions of exhausting exercis

Class I methanol masers in low-mass star formation regions

Four Class I maser sources were detected at 44, 84, and 95 GHz toward chemically rich outflows in the regions of low-mass star formation NGC 1333I4A, NGC 1333I2A, HH25, and L1157. One more maser was found at 36 GHz toward a similar outflow, NGC 2023. Flux densities of the newly detected masers are no more than 18 Jy, being much lower than those of strong masers in regions of high-mass star formation. The brightness temperatures of the strongest peaks in NGC 1333I4A, HH25, and L1157 at 44 GHz are higher than 2000 K, whereas that of the peak in NGC 1333I2A is only 176 K. However, rotational diagram analysis showed that the latter source is also a maser. The main properties of the newly detected masers are similar to those of Class I methanol masers in regions of massive star formation. The former masers are likely to be an extension of the latter maser population toward low luminosities of both the masers and the corresponding YSOs.Comment: 5 pages, 1 figure, Proc. IAU Symp. 287 "Cosmic Masers: from OH to H0". LSR velocities of the HH25 masers, which are presented in Table 1, are correcte

Second-layer nucleation in coherent Stranski-Krastanov growth of quantum dots

We have studied the monolayer-bilayer transformation in the case of the coherent Stranski-Krastanov growth. We have found that the energy of formation of a second layer nucleus is largest at the center of the first-layer island and smallest on its corners. Thus nucleation is expected to take place at the corners (or the edges) rather than at the center of the islands as in the case of homoepitaxy. The critical nuclei have one atom in addition to a compact shape, which is either a square of i*i or a rectangle of i*(i-1) atoms, with i>1 an integer. When the edge of the initial monolayer island is much larger than the critical nucleus size, the latter is always a rectangle plus an additional atom, adsorbed at the longer edge, which gives rise to a new atomic row in order to transform the rectangle into the equilibrium square shape.Comment: 6 pages, 4 figures. Accepted version, minor change