148 research outputs found

    Evidence of electron-irradiation activated creep in amorphous olivine at room temperature

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    Hydrodynamic structure of laminar flows with oppositely-swirled coaxial layers

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    The article is devoted to the theoretical study of hydrodynamics of laminar flows with coaxial layers swirled in opposite directions and moving along the pipe. Such flows in a turbulent range have a wide practical application potential in technologies of dissipation of mechanical energy and mixing multiphase and heterogeneous media in microbiology, chemistry, ecology, heat engineering, power engineering, engine and rocket engineering. The article describes the tensor of viscous tangents (τii) and normal (σii) stresses. The questions of stability of flow according to the Rayleigh (Ra) and Richardson (Ri) criteria are considered. Calculation formulas and graphs of radial-axial distributions of viscous stress components, local stability zones are given, the point of “crisis and decay of the flow” or “vortex breakdown” is indicated. The solutions are obtained in the form of Fourier-Bessel series. The analysis of the hydrodynamic structure of the flow is made

    Vasculoprotective Role of Olive Oil Compounds via Modulation of Oxidative Stress in Atherosclerosis

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    Existing evidence supports the significant role of oxidative stress in the endothelial injury, and there is a direct link between increased oxidative stress, and the development of endothelial dysfunction. Endothelial dysfunction precedes the development of atherosclerosis and subsequent cardiovascular disease (CVD). The overproduction of reactive oxygen species facilitates the processes, such as oxidative modification of low-density lipoproteins and phospholipids, reduction in the NOS-derived nitric oxide, and the functional disruption of high-density lipids that are profoundly involved in atherogenesis, inflammation, and thrombus formation in vascular cells. Thus, under oxidative stress conditions, endothelial dysfunction was found to be associated with the following endothelial alterations: reduced nitric oxide bioavailability, increased anticoagulant properties, increased platelet aggregation, increased expression of adhesion molecules, chemokines, and cytokines. In this review, we summarized the evidence indicating that endothelial damage triggered by oxidation can be diminished or reversed by the compounds of olive oil, a readily available antioxidant food source. Olive oil bioactive compounds exhibited a potent capability to attenuate oxidative stress and improve endothelial function through their anti-inflammatory, anti-oxidant, and anti-thrombotic properties, therefore reducing the risk and progression of atherosclerosis. Also, their molecular mechanisms of action were explored to establish the potential preventive and/or therapeutic alternatives to the pharmacological remedies available

    Small Dense Low-Density Lipoprotein as Biomarker for Atherosclerotic Diseases

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    Low-density lipoprotein (LDL) plays a key role in the development and progression of atherosclerosis and cardiovascular disease. LDL consists of several subclasses of particles with different sizes and densities, including large buoyant (lb) and intermediate and small dense (sd) LDLs. It has been well documented that sdLDL has a greater atherogenic potential than that of other LDL subfractions and that sdLDL cholesterol (sdLDL-C) proportion is a better marker for prediction of cardiovascular disease than that of total LDL-C. Circulating sdLDL readily undergoes multiple atherogenic modifications in blood plasma, such as desialylation, glycation, and oxidation, that further increase its atherogenicity. Modified sdLDL is a potent inductor of inflammatory processes associated with cardiovascular disease. Several laboratory methods have been developed for separation of LDL subclasses, and the results obtained by different methods can not be directly compared in most cases. Recently, the development of homogeneous assays facilitated the LDL subfraction analysis making possible large clinical studies evaluating the significance of sdLDL in the development of cardiovascular disease. Further studies are needed to establish guidelines for sdLDL evaluation and correction in clinical practice

    In-situ Plasma Studies using a Direct Current Microplasma in a Scanning Electron Microscope

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    Microplasmas can be used for a wide range of technological applications and to improve our understanding of fundamental physics. Scanning electron microscopy, on the other hand, provides insights into the sample morphology and chemistry of materials from the mm-down to the nm-scale. Combining both would provide direct insight into plasma-sample interactions in real-time and at high spatial resolution. Up till now, very few attempts in this direction have been made, and significant challenges remain. This work presents a stable direct current glow discharge microplasma setup built inside a scanning electron microscope. The experimental setup is capable of real-time in-situ imaging of the sample evolution during plasma operation and it demonstrates localized sputtering and sample oxidation. Further, the experimental parameters such as varying gas mixtures, electrode polarity, and field strength are explored and experimental VV-II curves under various conditions are provided. These results demonstrate the capabilities of this setup in potential investigations of plasma physics, plasma-surface interactions, and materials science and its practical applications. The presented setup shows the potential to have several technological applications, e.g., to locally modify the sample surface (e.g., local oxidation and ion implantation for nanotechnology applications) on the μ\mum-scale.Comment: LG, DC, and RDM contributed equally to this work. The videos mentioned in the manuscript can be found in the Zenodo repository linked in the pape

    Spread Dynamics of Leucosis in Cattle in Livestock Farms of the Russian Federation for 2000–2018

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    Leucosis occupies a leading position in the modern nosological structure of cattle infectious diseases. This is due to the high infection of livestock and large economic damage in affected farms [1–3]. Leucosis is a chronic tumor disease caused by an RNA-containing virus of the Retroviridae family. The disease is characterized by uncontrolled reproduction of immature hematopoietic cells [4, 5]. The objective is to assess in dynamics the indicators of cattle infection with the leucosis virus and the incidence of leucosis in farms of all categories of the Russian Federation in the period of 2000–2018. The data of the analysis of the epizootic situation for leucosis in cattle in farms of all categories of the Russian Federation for 2000-2018 are presented. Over this period of time, the number of diagnostic serological studies in the immunodiffusion reaction increased 1.88 times in all subjects. According to the results of epizootological monitoring in farms of all categories of the Russian Federation, the rates of infection of the bovine leucosis virus decreased 1.89 times, the incidence rates decreased 2.02 times. At present, the epizootic situation has improved markedly, but so far there are problems with incomplete release of farms from leucosis in cattle. It is necessary to continue work on the elimination of this dangerous chronic disease in farms of all categories in the territory of the Russian Federation
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