4,849 research outputs found

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

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    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

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

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    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

    Vertical Structure of the Outer Accretion Disk in Persistent Low-Mass X-Ray Binaries

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    We have investigated the influence of X-ray irradiation on the vertical structure of the outer accretion disk in low-mass X-ray binaries by performing a self-consistent calculation of the vertical structure and X-ray radiation transfer in the disk. Penetrating deep into the disk, the field of scattered X-ray photons with energy E10E\gtrsim10\,keV exerts a significant influence on the vertical structure of the accretion disk at a distance R1010R\gtrsim10^{10}\,cm from the neutron star. At a distance R1011R\sim10^{11}\,cm, where the total surface density in the disk reaches Σ020\Sigma_0\sim20\,g\,cm2^{-2}, X-ray heating affects all layers of an optically thick disk. The X-ray heating effect is enhanced significantly in the presence of an extended atmospheric layer with a temperature Tatm(2÷3)×106T_{atm}\sim(2\div3)\times10^6\,K above the accretion disk. We have derived simple analytic formulas for the disk heating by scattered X-ray photons using an approximate solution of the transfer equation by the Sobolev method. This approximation has a 10\gtrsim10\,% accuracy in the range of X-ray photon energies E<20E<20\,keV.Comment: 19 pages, 8 figures, published in Astronomy Letter

    Effects of broadening and electron overheating in tunnel structures based on metallic clusters

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    We study the influence of energy levels broadening and electron subsystem overheating in island electrode (cluster) on current-voltage characteristics of three-electrode structure. A calculation scheme for broadening effect in one-dimensional case is suggested. Estimation of broadening is performed for electron levels in disc-like and spherical gold clusters. Within the two-temperature model of metallic cluster and by using a size dependence of the Debye frequency the effective electron temperature as a function of bias voltage is found approximately. We suggest that the effects of broadening and electron overheating are responsible for the strong smoothing of current-voltage curves, which is observed experimentally at low temperatures in structures based on clusters consisting of accountable number of atoms.Comment: 8 pages, 5 figure

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

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    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

    Safety and pharmacological efficiency (influence on muscular dysfunction) of new derivatives of chromon-3-aldehyde

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    Objective: to estimate the safety of application of new derivatives of chromon-3-aldehyde and the possibility of its application for correction of muscular dysfunction. Materials and methods: the experiment was performed on 120 mice-males of the Balb/c line. Research objects - halogenated derivatives of chromon-3-aldehyde under codes of X3AF and X3ACl. The safety assessment of its application included the determination ofits single dose toxicity with calculation of LD50 using the Finni method. Further, the influence of derivatives on the development of muscular dysfunction using the myostimmulation test after its preventive introduction was studied. Results: the conducted research showed that new halogenated derivatives of chromon-3-aldehyde under codes of X3AF and X3ACl possessed an optimum profile of safety and wereable to alleviate the manifestations of muscle dysfunction. At the same time the substanceX3AF surpassed the substance X3ACl and comparison drug «Mildronat» in the size of pharmacological action. Conclusions: the low toxicity and high pharmacological efficiency of new halogenated derivatives of chromon-3-aldehyde makes these compounds the perspective o

    Magnetostimulated Chandges of Microhardness in Potassium Acid Phthalate Crystals

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    A decrease in microhardness along the (010) cleavage in potassium acid phthalate single crystals by 15--18% after the application of a permanent magnetic field was revealed for the first time. It is shown that the effect revealed is of the volume character. The role of interlayer water in the processes stimulated by a magnetic field is studied., Interlayer water plays does not cause the observed changes it only plays the part of an indicator of these changes in potassium acid phthalate crystals in a magnetic field. It is established that microhardness in the (100) plane of the crystal in an applied a magnetic field first increases by 12--15% and then remains constant in time within the accuracy of the experiment. The possibility of varying the crystal structure of potassium acid phthalate crystals by applying magnetic fields inducing rearrangement in the system of hydrogen bonds or in the defect structure is discussed.Comment: 6 pages, 7 figure

    Pharmacological characteristics of intranasal dosage forms containing Ginkgo biloba extracts

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    To evaluate specific pharmacological activity of the developed dosage forms of ginkgo bilob

    Backward asymmetry of the Compton scattering by an isotropic distribution of relativistic electrons: astrophysical implications

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    The angular distribution of low-frequency radiation after single scattering by an isotropic distribution of relativistic electrons considerably differs from the Rayleigh angular function. In particular, the scattering by an ensemble of ultra-relativistic electrons obeys the law p=1-cos(alpha), where alpha is the scattering angle; hence photons are preferentially scattered backwards. We discuss some consequences of this fact for astrophysical problems. We show that a hot electron-scattering atmosphere is more reflective than a cold one: the fraction of incident photons which become reflected having suffered a single scattering event can be larger by up to 50 per cent in the former case. This should affect the photon exchange between cold accretion disks and hot coronae or ADAF flows in the vicinity of relativistic compact objects; as well as the rate of cooling (through multiple inverse-Compton scattering of seed photons supplied from outside) of optically thick clouds of relativistic electrons in compact radiosources. The forward-backward scattering asymmetry also causes spatial diffusion of photons to proceed slower in hot plasma than in cold one, which is important for the shapes of Comptonization spectra and the time delays between soft and hard radiations coming from variable X-ray sources.Comment: 20 pages, 3 figures, to appear in Astronomy Letters, added reference

    X-ray line formation in the spectrum of SS 433

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    The mechanisms for the formation of X-ray lines in the spectrum of SS 433 are investigated by taking into account the radiative transfer inside the jets. The results of Monte Carlo numerical simulations are presented. The effect of a decrease in line intensity due to scattering inside the jet turns out to be pronounced, but it does not exceed 60% in magnitude on the entire grid of parameters. The line broadening due to scattering, nutational motion, and the contribution of satellites can lead to overestimates of the jet opening angle Θ\Theta from the line widths in Chandra X-ray observations. The fine structure of the lines turns out to be very sensitive to the scattering effects. This makes its investigation by planned X-ray observatories equipped with high-resolution spectrometers (primarily Astro-H) a powerful tool for diagnosing the parameters of the jets in SS 433.Comment: 23 pages, 14 figures, to be published in Astronomy Letters, v. 38, n. 7, p. 443 (2012
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