Numerical Simulation of the Medical Linear Accelerator Electron Beams Absorption by ABS-Plastic doped with Metal

In this paper the numerical simulation results of the dose spatial distribution of the medical electron beams in ABS-plastic doped with different concentrations of lead and zinc are shown. The dependences of the test material density on the lead and zinc mass concentrations are illustrated. The depth dose distributions of the medical electron beams in the modified ABS-plastic for three energies 6 MeV, 12 MeV and 20 MeV are tested. The electron beam shapes in the transverse plane in ABS-plastic doped with different concentrations of lead and zinc are presented

Методика оптимизации геометрических размеров чувствительных элементов измерительных преобразователей силы сложной формы

У статті на прикладі пружних вимірювальних перетворювачів сили розглядається методика оптимізації геометричних розмірів з використанням системи 3D-моделювання й конструювання SolidWorks у сполученні з додатком до неї COSMOS Works.There article we consider device end optimization to use the system Solid Works end COSMOS Works.В статье на примере измерительных упругих преобразователей силы рассмотрена методика оптимизации их геометрических размеров с помощью использования системы 3D-моделирования и конструирования SolidWorks совместно с дополнением к ней COSMOS Works

Stabilization of enzymes by dormancy autoinducers as a possible mechanism of resistance of resting microbial forms

Alkyl-substituted hydroxybenzenes (AHBs), autoinducers of microbial dormancy (or d1 factors), were found to stabilize the structure of protein macromolecules, making them metabolically less active and more resistant to stresses. In vitro experiments with the Bacillus intermedius ribonuclease and chymotrypsin showed that the degree of the physical and chemical stability of these enzymes treated with AHBs depends on their concentration and incubation time. Experiments with RNase, which is capable of refolding, i.e., renaturation after heat denaturation, revealed that AHBs efficiently interact with both intact and denatured proteins. The data obtained allow the inference to be made that d1 factors may play the role of natural chemical chaperons, blocking metabolism in dormant cells through the formation of catalytically inactive thermostable complexes with enzymes. © 2000 MAIK "Nauka/Interperiodica"

Comparative benchmark analysis of coverage by specialists involved in healthcare provision to patients with cardiovascular diseases in the regions of the Northwestern Federal District

Control of cardiovascular diseases  (CVDs), which are the cause of premature mortality and high economic  costs,  is one of the priorities of social policy. Human resources are a key link in health system performance.  In Russia, there is a significant geographical  heterogeneity  in the distribution of medical workers and structural disproportions  in certain specialties.  Regional  differences  in the availability of specialists in cardiology system have not been studied enough.Aim. To perform a comparative benchmark analysis of coverage by specialists involved  in healthcare  provision  to patients with cardiovascular  diseases  in the regions of the Northwestern Federal District (NWFD), identifying regional differences for the period from 2015 to 2019.Material and methods. To assess the number of specialists involved in providing care to patients with CVDs, data from the federal statistical monitoring forms №30 “Information on a medical organization” for 2015-2019 of the subjects of the Northwestern Federal District were used. Multiple linear regression was used to compare the basic estimated parameters of provision per 10000 population with specialists at the level of district as a whole and in NWFD regions  with data for Russia as a whole. P<0,05 was considered significant.Results. Among the subjects of Northwestern Federal District, differences  were revealed  in all specialties  of varying severity. While the estimated parameter of provision with cardiologists  in Russia is 0,896 (95%  CI, 0,794-0,998),  there are differences  in the regions in a wide range from -0,446 (Vologda Oblast) to +0,502 (St. Petersburg).  Regional  differences  in the provision of vascular radiology specialists from the basic estimated level for Russia were observed  only in two subjects. At the same time, for all subjects in general, an increase in the indicator from 2015 to 2019 by 0,011 [95% CI, 0,006; 0,016] per year (p<0,001) was observed.  The smallest range of differences was observed for cardiovascular surgeons:  with a baseline  estimate  in Russia of 0,158 [95% CI, 0,140; 0,176] the range of differences was from -0,086 to +0,198. For emergency  medicine paramedic, the largest number of subjects with positive values of the statistical correction of the average relative to Russia was noted (7 out of 11 regions). For neurologists and intensivists, on the contrary, the largest number of subjects with negative values (7 out of 11 regions)  was revealed.  Structural staff disproportions in cardiology care system were revealed.Conclusion. In the NWFD, in general, coverage  by specialists involved in health-care provision for CVD are higher than the estimated base level for Russia. However,  their uneven distribution within the district and its subjects is observed. The demonstrated mathematical approach to assessing staff differences  at the subject or district level can be used to develop measures to achieve the goals of the regional health personnel policy

Ultrashort filaments of light in weakly-ionized, optically-transparent media

Modern laser sources nowadays deliver ultrashort light pulses reaching few cycles in duration, high energies beyond the Joule level and peak powers exceeding several terawatt (TW). When such pulses propagate through optically-transparent media, they first self-focus in space and grow in intensity, until they generate a tenuous plasma by photo-ionization. For free electron densities and beam intensities below their breakdown limits, these pulses evolve as self-guided objects, resulting from successive equilibria between the Kerr focusing process, the chromatic dispersion of the medium, and the defocusing action of the electron plasma. Discovered one decade ago, this self-channeling mechanism reveals a new physics, widely extending the frontiers of nonlinear optics. Implications include long-distance propagation of TW beams in the atmosphere, supercontinuum emission, pulse shortening as well as high-order harmonic generation. This review presents the landmarks of the 10-odd-year progress in this field. Particular emphasis is laid to the theoretical modeling of the propagation equations, whose physical ingredients are discussed from numerical simulations. Differences between femtosecond pulses propagating in gaseous or condensed materials are underlined. Attention is also paid to the multifilamentation instability of broad, powerful beams, breaking up the energy distribution into small-scale cells along the optical path. The robustness of the resulting filaments in adverse weathers, their large conical emission exploited for multipollutant remote sensing, nonlinear spectroscopy, and the possibility to guide electric discharges in air are finally addressed on the basis of experimental results.Comment: 50 pages, 38 figure

Study of Bars and Wires Properties from Al-REM System Alloy

The article presents the results of studies on the production of wire with a diameter of 0,5 mm from aluminum alloy 01417 with a content of rare-earth metals (REM) in the amount of 7–9 % for aircraft construction needs. The deformation modes, the experimental technique and equipment for the implementation of the proposed technology are described.В статье представлены результаты исследований по получению проволоки диаметром 0,5 мм из алюминиевого сплава 01417 с содержанием редкоземельных металлов (РЗМ) в количестве 7–9 % для нужд авиастроения. Описаны режимы деформации, методика проведения экспериментов и оборудование для реализации предложенной технологии.Исследования выполнены при финансовой поддержке РФФИ, Правительства Красноярского края и ООО «Научно-производственный центр Магнитной гидродинамики» в рамках научного проекта № 18-48-242021 «Разработка фундаментальных основ получения деформированных полуфабрикатов электротехнического назначения из высоколегированных сплавов системы Al-РЗМ с применением методов совмещенной обработки и исследование их реологических свойств»

A novel role for syndecan-3 in angiogenesis.

Syndecan-3 is one of the four members of the syndecan family of heparan sulphate proteoglycans and has been shown to interact with numerous growth factors via its heparan sulphate chains. The extracellular core proteins of syndecan-1,-2 and -4 all possess adhesion regulatory motifs and we hypothesized that syndecan-3 may also possess such characteristics. Here we show that a bacterially expressed GST fusion protein consisting of the entire mature syndecan-3 ectodomain has anti-angiogenic properties and acts via modulating endothelial cell migration. This work identifies syndecan-3 as a possible therapeutic target for anti-angiogenic therapy.This work was funded by Arthritis Research-UK (Grant No. 19207) and funds from the William Harvey Research Foundation both to JRW

Демаскировка нарушений почвенного покрова с помощью моделирования динамики параметров наземной растительности

Стаття присвячена проблематиці виявлення незначних змін у характері ґрунтового покриву за допомогою динамічної моделі, що описує взаємодію колориметричних параметрів. На наведеному прикладі цифрового космічного знімка ділянки поверхні показано використання системних ефектів для цілей демаскування порушення ґрунтового покриву.The "Introduction" describes topicality and importance of revealing the soil cover's disruption for a wide range of fields. It was shown that spectral brightness and colorimetric parameters of ground vegetation can be used for this task. However, a traditional scheme of data processing for remote sensing requires a long-term observations and cannot always be applied, if quick decision-making is necessary or there is lack of information. Such cases require the use of special methods, one of which is a dynamic model developed with authors' participation based on the following basic relationships: (+,-) (-, -) (+, 0), (-, 0) (0,0). The section "Brief description of a dynamic model" describes the basic principles of dynamic systems used to solve the problem. Using above-mentioned relationships, the dynamics of a system consisting of several components is constructed and its main properties are listed. The main feature of this model is that the identification of structure and parameters of the dynamic system does not required sequential order of observations (as for models based on time series). This feature of the model enables for identifying the system's parameters of dynamics of the natural system to use information from a single picture taken from the spacecraft rather than long-term observations. The section "Materials and Methods" describes specific colorimetric parameters used to analyze the vegetation cover. The section "obtained results" contains an example of the model's application to a satellite image for detecting the differences in two sites of a field with vegetation. One site is a recultivated area near the liquidated gas-oil well, another site is non-recultivated area at a considerable distance from the well (500-1000 m). The simulation results are described by eight signed graphs (4 graphs for each sites), whose structure allows to identify the system differences between the two cases. The section "Conclusions" summarizes the results of previous sections. The prospects of the use of proposed methodology for soil cover's disruption are shown. Advantages of this methodology over other approaches are highlighted.Статья посвящена проблематике выявления незначительных изменений в характере почвенного покрова с помощью динамической модели, описывающей взаимодействие колориметрических параметров. На приведенном примере цифрового космического снимка участка поверхности показано использование системных эффектов для целей демаскировки нарушение почвенного покрова