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

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

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

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

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

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 $E\gtrsim10$\,keV exerts a significant influence on the vertical structure of the accretion disk at a distance $R\gtrsim10^{10}$\,cm from the neutron star. At a distance $R\sim10^{11}$\,cm, where the total surface density in the disk reaches $\Sigma_0\sim20$\,g\,cm$^{-2}$, 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 $T_{atm}\sim(2\div3)\times10^6$\,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 $\gtrsim10$\,% accuracy in the range of X-ray photon energies $E<20$\,keV.Comment: 19 pages, 8 figures, published in Astronomy Letter

The profile of a narrow line after single scattering by Maxwellian electrons: relativistic corrections to the kernel of the integral kinetic equation

The frequency distribution of photons in frequency that results from single Compton scattering of monochromatic radiation on thermal electrons is derived in the mildly relativistic limit. Algebraic expressions are given for (1) the photon redistribution function, K(nu,Omega -> nu',Omega'), and (2) the spectrum produced in the case of isotropic incident radiation, P(nu -> nu'). The former is a good approximation for electron temperatures kT_e < 25 keV and photon energies hnu < 50 keV, and the latter is applicable when hnu(hnu/m_ec^2) < kT_e < 25 keV, hnu < 50 keV. Both formulae can be used for describing the profiles of X-ray and low-frequency lines upon scattering in hot, optically thin plasmas, such as present in clusters of galaxies, in the coronae of accretion disks in X-ray binaries and AGNs, during supernova explosions, etc. Both formulae can also be employed as the kernels of the corresponding integral kinetic equations (direction-dependent and isotropic) in the general problem of Comptonization on thermal electrons. The K(nu,Omega -> nu',Omega') kernel, in particular, is applicable to the problem of induced Compton interaction of anisotropic low-frequency radiation of high brightness temperature with free electrons in the vicinity of powerful radiosources and masers. Fokker-Planck-type expansion (up to fourth order) of the integral kinetic equation with the P(nu -> nu') kernel derived here leads to a generalization of the Kompaneets equation. We further present (1) a simpler kernel that is necessary and sufficient to derive the Kompaneets equation and (2) an expression for the angular function for Compton scattering in a hot plasma, which includes temperature and photon energy corrections to the Rayleigh angular function.Comment: 29 pages, 17 figures, accepted for publication in ApJ, uses emulateapj.sty, corrects misprints in previous astro-ph versio

Оценка выраженности легочного фиброза по данным аутопсии у реконвалесцентов COVID-19: сопоставление с данными количественной КТ легких в острой фазе заболевания

INTRODUCTION: After the COVID-19 pandemic, there is increasing evidence that many patients show fibrous changes in lung tissue accompanied by functional lung disorders. Objective data on the histopathogenesis of such changes is still insufficient. Prospective studies are required to fully assess the consequences of these clinical manifestations.OBJECTIVE: Evaluation of the capabilities of digital processing of histological preparations of lung tissue and their comparison with quantitative CT data of lung patients in the acute phase of COVID-19.MATERIALS AND METHODS: The study included data from patients after COVID-19 (7 women and 3 men aged 47 to 93 years) who died after the acute phase of COVID-19 from extrapulmonary causes. The control group included data from 7 people (5 women and 2 men aged 35 to 93 years) who died shortly after hospitalization from extrapulmonary causes (myocardial infarction or acute cerebral stroke), with no signs of lung diseases, including autopsy results. Digital processing of histological preparations of lung tissue obtained during autopsy was carried out, and their comparison with the results of quantitative semi-automatic processing of CT data.Statistics. Beta regression (mgcv library) was used. The model was characterized by a pseudodetermination coefficient R2. The association was considered statistically significant at p&lt;0.05.RESULTS: A reliable dependence of the severity of fibrous changes in histological samples on the results of quantitative analysis of CT images of patients in the acute period of COVID-19 was demonstrated.DISCUSSION: Extrapolation of lung autopsy data through quantitative CT assessment is one of the ways to pre-diagnose and identify groups of patients who require specific treatment of post-COVID-19 pulmonary fibrosis.CONCLUSION. Computerized digital processing of histological images made it possible to correctly compare the histopathological examination data with the CT picture in COVID-19, which could potentially have a prognostic value in the search for more effective treatment strategies.ВВЕДЕНИЕ: После пандемии COVID-19 появляется все больше доказательств того, что у многих реконвалесцентов COVID-19 выявляются фиброзные изменения легочной ткани, сопровождающиеся функциональными нарушениями легких. Объективных данных о гистопатогенезе подобных изменений по-прежнему недостаточно. Для полной оценки последствий этих клинических проявлений требуются проспективные исследования.ЦЕЛЬ: Оценка возможностей цифровой обработки гистологических препаратов легочной ткани и их сопоставление с данными количественной КТ легких пациентов в острой фазе COVID-19.МАТЕРИАЛЫ И МЕТОДЫ: В исследование были включены данные пациентов-реконвалесцентов COVID-19 (7 женщин и 3 мужчин в возрасте от 47 до 93 лет), умерших после острой фазы COVID-19 от внелегочных причин. В контрольную группу вошли данные 7 человек (5 женщин и 2 мужчин в возрасте от 35 до 93 лет), умерших вскоре после госпитализации от внелегочных причин (ОКС либо ОНМК), без каких-либо признаков заболеваний легких, в том числе по результатам аутопсии. Проводилась цифровая обработка полученных при аутопсии гистологических препаратов легочной ткани и их сопоставление с результатами количественной полуавтоматической обработки данных СКТ. Статистика. Использовалась бета-регрессия (библиотека mgcv). Модель характеризовалась коэффициентом псевдодетерминации R2. Ассоциация признавалась статистически значимой при p&lt;0,05.РЕЗУЛЬТАТЫ: Продемонстрирована достоверная зависимость выраженности фиброзных изменений в гистологических образцах от результатов количественного анализа КТ-изображений пациентов в остром периоде COVID-19.ОБСУЖДЕНИЕ: Экстраполяция данных аутопсийного исследования легких через количественную оценку КТ является одним из способов предварительной диагностики и определения групп пациентов, которым требуется специфическое лечение пост-COVID-19 легочного фиброза.ЗАКЛЮЧЕНИЕ: Компьютеризированная цифровая обработка гистологических изображений позволила корректно сопоставить данные гистопатологического исследования с КТ-картиной при COVID-19, что потенциально может иметь прогностическое значение в поиске более эффективных стратегий лечения

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

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

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