522 research outputs found
Generation of small-scale structures in the developed turbulence
The Navier-Stokes equation for incompressible liquid is considered in the
limit of infinitely large Reynolds number. It is assumed that the flow
instability leads to generation of steady-state large-scale pulsations. The
excitation and evolution of the small-scale turbulence is investigated. It is
shown that the developed small-scale pulsations are intermittent. The maximal
amplitude of the vorticity fluctuations is reached along the vortex filaments.
Basing on the obtained solution, the pair correlation function in the limit
is calculated. It is shown that the function obeys the Kolmogorov law
.Comment: 18 page
Manifestation of systemic toxicity in rats after a short-time inhalation of lead oxide nanoparticles
Outbred female rats were exposed to inhalation of lead oxide nanoparticle aerosol produced right then and there at a concentration of 1.30 ± 0.10 mg/m3 during 5 days for 4 h a day in a nose-only setup. A control group of rats were sham-exposed in parallel under similar conditions. Even this short-time exposure of a relatively low level was associated with nanoparticles retention demonstrable by transmission electron microscopy in the lungs and the olfactory brain. Some impairments were found in the organism’s status in the exposed group, some of which might be considered lead-specific toxicological outcomes (in particular, increase in reticulocytes proportion, in δ-aminolevulinic acid (δ-ALA) urine excretion, and the arterial hypertension’s development). © 2020 by the authors. Licensee MDPI, Basel, Switzerland.Funding: This work was funded by the budget of the Ekaterinburg Medical Research Center for Prophylaxis and Health Protection in Industrial Workers
Using Strategy Improvement to Stay Alive
We design a novel algorithm for solving Mean-Payoff Games (MPGs). Besides
solving an MPG in the usual sense, our algorithm computes more information
about the game, information that is important with respect to applications. The
weights of the edges of an MPG can be thought of as a gained/consumed energy --
depending on the sign. For each vertex, our algorithm computes the minimum
amount of initial energy that is sufficient for player Max to ensure that in a
play starting from the vertex, the energy level never goes below zero. Our
algorithm is not the first algorithm that computes the minimum sufficient
initial energies, but according to our experimental study it is the fastest
algorithm that computes them. The reason is that it utilizes the strategy
improvement technique which is very efficient in practice
Some Peculiarities in the Dose Dependence of Separate and Combined In Vitro Cardiotoxicity Effects Induced by CdS and PbS Nanoparticles With Special Attention to Hormesis Manifestations
Spherical nanoparticles (NPs) of cadmium and lead sulfides (diameter 37 ± 5 and 24 ± 4 nm, respectively) have been found to be cytotoxic for HL-1 cardiomyocytes as evidenced by decrease in adenosine triphosphate–dependent luminescence. Cadmium sulfide (CdS)-NPs were discovered to produce a much greater cytotoxic impact than lead sulphide (PbS)-NP. Given the same dose range, CdS-NP reduced the number of calcium spikes. A similar effect was observed for small doses of PbS-NP. In addition to cell hypertrophy under the impact of certain doses of CdS-NP and PbS-NP, doses causing cardiomyocyte size reduction were identified. For these 3 outcomes, we obtained both monotonic “dose–response” functions (well approximated by the hyperbolic function) and different variants of non-monotonic ones for which we found adequate mathematical expressions by modifying certain models of hormesis available in the literature. Data analysis using a response surface linear model with a cross-term provided new support to the previously established postulate that a diversity of types of joint action characteristic of one and the same pair of damaging agents is one of the important assertions of the general theory of combined toxicity. © The Author(s) 2020
Main results obtained in a series of animal experiments for the assessment of the organism’s responses to metallic nanoparticles (self-review).
The heats of formation of the haloacetylenes XCCY [X, Y = H, F, Cl]: basis set limit ab initio results and thermochemical analysis
The heats of formation of haloacetylenes are evaluated using the recent W1
and W2 ab initio computational thermochemistry methods. These calculations
involve CCSD and CCSD(T) coupled cluster methods, basis sets of up to spdfgh
quality, extrapolations to the one-particle basis set limit, and contributions
of inner-shell correlation, scalar relativistic effects, and (where relevant)
first-order spin-orbit coupling. The heats of formation determined using W2
theory are: \hof(HCCH) = 54.48 kcal/mol, \hof(HCCF) = 25.15 kcal/mol,
\hof(FCCF) = 1.38 kcal/mol, \hof(HCCCl) = 54.83 kcal/mol, \hof(ClCCCl) = 56.21
kcal/mol, and \hof(FCCCl) = 28.47 kcal/mol. Enthalpies of hydrogenation and
destabilization energies relative to acetylene were obtained at the W1 level of
theory. So doing we find the following destabilization order for acetylenes:
FCCF ClCCF HCCF ClCCCl HCCCl HCCH. By a combination of W1
theory and isodesmic reactions, we show that the generally accepted heat of
formation of 1,2-dichloroethane should be revised to -31.80.6 kcal/mol, in
excellent agreement with a very recent critically evaluated review. The
performance of compound thermochemistry schemes such as G2, G3, G3X and CBS-QB3
theories has been analyzed.Comment: Mol. Phys., in press (E. R. Davidson issue
Organization, perspectives of development, and scientific-methodological approaches to the occupational health risk management within the system “Occupational medicine” in the Sverdlovsk oblast, Russia
In this paper the results of the first steps of implementation of the system “Occupational Medicine" created in the Sverdlovsk Region, its role in bettering the medical care for workers' health and in decreasing occupational diseases incidence, as well as ways and perspectives of its further development are presented.В статье приводятся результаты первых этапов реализации созданной в Свердловской области системы «Медицина труда», ее роль в улучшении медицинского обслуживания трудящихся, снижении профессиональной заболеваемости, пути и перспективы ее дальнейшего развития
Implementation of requirements of current sanitary rules and norms when de-veloping buffer zones projects of industrial enterprises and other objects
The article describes the experience of the Federal State Scientific Enterprise «The Ekaterinburg Medical Scientific Center of Prevention and Protection of Health of the Workers of Industrial Enterprises» implementing the requirements for the current sanitary norms and rules for the work related to justifying the size the buffer zones of various objects, setting the integrated boundaries of the buffer zones of the industrial units; exemplifies the branch interaction in this field; highlights the problems connected with developing the buffer zone projects. The foundation of the cooperation is the deep analysis of the current land, town-building and sanitary legislation, normative and methodological basis and the results of multiyear work at the aluminum, titanium-magnesium, mining enterprises, ferrous and non-ferrous metals, pipe production, as well as food production (JSC «BAZ», JSC «UAZ», JSC «Ura-lasbest», JSC «VGOK», R M M Z - branch of JSC «NSMMZ», JSC «VSMPO-AVISMA», JSC «NTMK», JSC «SEAL and Co», JSC «KUMZ», JSC «SinTZ», JSC «PNTZ», «Logopark Pyshma», JSC «Polyplast-UralSib», etc), permitting to develop the methodological approaches to solving the problems of changing the boundaries of the buffer zones under the conditions of the town-building situation and grounding the requirements for the data in the design calculations and finally established buffer zones, being the foundation for the methodological and normative documents adopted at the federal and regional levels.В статье показан опыт работы ФГУН «ЕМНЦ П03РПП» по реализации требований действующих санитарных норм и правил к работам по обоснованию размеров санитарно-защитных зон (C33) различных объектов, установлению границ единых C33 промузлов; приведены примеры межведомственного взаимодействия в этой области; освещены проблемы, связанные с разработкой проектов C33. В основу совместных работ положен углубленный анализ действующего земельного, градостроительного и санитарного законодательства, нормативно-методической базы, и результаты многолетней работы на предприятиях алюминиевой, титано-магниевой, горно-добывающей промышленности, черной и цветной металлургии, производства труб, а так же предприятий пищевых отраслей промышленности (ОАО БАЗ», ОАО «УАЗ», ОАО «Ураласбест», ОАО «ВГОК», РМ М З - филиал ЗАО «НСММЗ», ОАО «ВСМПО-АВИСМА», ОАО «НТМК», ОАО «СЕАЛ и К», ОАО «КУМЗ», ОАО «СинТЗ», ОАО «ПНТЗ», «Логопарк Пышма», ОАО «Полипласт-УралСиб» и др.), что позволило разработать методические подходы к решению вопросов по изменению границ СЗЗ в условиях сложившейся градостроительной ситуации и обосновать требования к представлению данных в проектах расчетных и окончательно установленных СЗЗ, которые положены в основу методических и нормативных документов, принятых на федеральном и региональном уровнях
Toxic effects of low-level long-term inhalation exposures of rats to nickel oxide nanoparticles
Rats were exposed to nickel oxide nanoparticles (NiO-NP) inhalation at 0.23 ± 0.01 mg/m3 for 4 h a day 5 times a week for up to 10 months. The rat organism responded to this impact with changes in cytological and some biochemical characteristics of the bronchoalveolar lavage fluid along with a paradoxically little pronounced pulmonary pathology associated with a rather low chronic retention of nanoparticles in the lungs. There were various manifestations of systemic toxicity, including damage to the liver and kidneys; a likely allergic syndrome as indicated by some cytological signs; transient stimulation of erythropoiesis; and penetration of nickel into the brain from the nasal mucous membrane along the olfactory pathway. Against a picture of mild to moderate chronic toxicity of nickel, its in vivo genotoxic effect assessed by the degree of DNA fragmentation in nucleated blood cells (the RAPD test) was pronounced, tending to increasing with the length of the exposure period. When rats were given orally, in parallel with the toxic exposure, a set of innocuous substances with differing mechanisms of expected bioprotective action, the genotoxic effect of NiO-NPs was found to be substantially attenuated. © 2019 by the authors. Licensee MDPI, Basel, Switzerland.For modeling chronic intoxication development under low-level but long-term inhalation exposures to NiO nanoparticles, the experiments were carried out on outbred white female rats from our own breeding colony with an initial body weight of 150–220 g, with a minimum of 12 animals in exposed and control groups. Rats were housed in conventional conditions, breathed unfiltered air, and were fed standard balanced food. The experiments were planned and implemented in accordance with the “International guiding principles for biomedical research involving animals” developed by the Council for International Organizations of Medical Sciences (1985) and were approved by the Ethics Committee of the Ekaterinburg Medical Research Center Medical for Prophylaxis and Health Protection in Industrial Workers
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