502 research outputs found

    On the hierarchy of partially invariant submodels of differential equations

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    It is noticed, that partially invariant solution (PIS) of differential equations in many cases can be represented as an invariant reduction of some PIS of the higher rank. This introduce a hierarchic structure in the set of all PISs of a given system of differential equations. By using this structure one can significantly decrease an amount of calculations required in enumeration of all PISs for a given system of partially differential equations. An equivalence of the two-step and the direct ways of construction of PISs is proved. In this framework the complete classification of regular partially invariant solutions of ideal MHD equations is given

    Spectrophotometric experiment on the Verera-11 and Venera-12 descent vehicles: Some results of the analysis of the spectrum of the daytime sky of Venus

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    The spectra of the daytime sky of Venus were recorded on the Venera-11 and Venera-12 descent vehicles at various altitudes above the planet's surface, within the interval of 4500 to 12,000 Angstroms. The angular distribution of the brightness of the scattered radiation was recorded and the ratio of water and carbon dioxide were studied, with respect to the cloud cover boundaries

    Spray nozzle designs for agricultural aviation applications

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    Techniques of generating monodisperse sprays and information concerning chemical liquids used in agricultural aviation are surveyed. The periodic dispersion of liquid jet, the spinning disk method, and ultrasonic atomization are the techniques discussed. Conceptually designed spray nozzles for generating monodisperse sprays are assessed. These are based on the classification of the drops using centrifugal force, on using two opposing liquid laden air jets, and on operating a spinning disk at an overloaded flow. Performance requirements for the designs are described and estimates of the operational characteristics are presented

    Effect of audiovisual stimulation on the psychophysiological functions in track-and-field athletes

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    In 18- to 23-year-old athletes specialized in field-and-track athletics, the psychophysiological status (cognitive, psychoemotional, and neurodynamic indicators) and the spectral power of the main EEG rhythms, and the heart rate variability prior to and after the course of audiovisual stimulation (AVS) training (the experimental group) were studied as compared with athletes not receiving AVS (the control group). It has been shown that the AVS training sessions in the experimental group caused improvements to the psychoemotional (the levels of anxiety and neuroticism decreased, while the motivation to achieve success and the hardiness level increased), cognitive, and neurodynamic indicators (the volume of mechanical memory and the speeds of attention switching and simple visual-motor responses increased, while the variation of anticipatory and delayed responses to a moving object became reduced). Increases have also been recorded in the high-frequency EEG α2-subrange rhythm power and the parasympathetic nervous system activity, while the autonomic regulation contour activity was enhanced, and more efficient heart activity at rest was formed after the AVS training course in the experimental group compared to the control. This leads to the conclusion about a positive effect of the AVS training course received by athletes engaged in track-and-field athletics on their psychophysiological parameters and autonomic regulation mechanisms

    SIMCOMP/SUBCOMP: chemical structure search servers for network analyses

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    One of the greatest challenges in bioinformatics is to shed light on the relationship between genomic and chemical significances of metabolic pathways. Here, we demonstrate two types of chemical structure search servers: SIMCOMP (http://www.genome.jp/tools/simcomp/) for the chemical similarity search and SUBCOMP (http://www.genome.jp/tools/subcomp/) for the chemical substructure search, where both servers provide links to the KEGG PATHWAY and BRITE databases. The SIMCOMP is a graph-based method for searching the maximal common subgraph isomorphism by finding the maximal cliques in the association graph. In contrast, the SUBCOMP is an extended method for solving the subgraph isomorphism problem. The obtained links to PATHWAY or BRITE databases can be used to interpret as the biological meanings of chemical structures from the viewpoint of the various biological functions including metabolic networks

    Analysis of the influence of chronic heart failure type on changes in the microelement composition of myocardial tissue in patients of senile age

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    Aim: conduct a comparative analysis of the content and distribution of macroelements (Ca2+, K+, Mg2+, and Na+) in myocardial tissue according to autopsy data in elder patients with CHF, depending on the LV E

    Pharmacotherapy for the prevention of the progression of chronic heart failure in elderly patients with coronary heart disease

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    Aim: chronic heart failure (CHF), which occurs as a result of common cardiovascular diseases in the elderly, combined with age-related changes in both structural and functional features of the heart. Myocardial remodeling is an essential substrate that determines the occurrence and progression of CHF in elderly patient

    System for Synchronous Detection Trace of Explosives and Drags Substances on Human Fingers

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    AbstractThe sampling unit of the device, based on ion mobility spectroscopy technique, for detection of ultra small (trace) substances concentration on human fingers and documents is described. The vapor pressure of many dangerous substances is very small; so the heating of an investigated surface is needed for effective detection. However the direct heating of the human fingers by irradiation of the gas-discharge lamp is not effective because a small concentration of the melamine (pigment of the black or brown color) in the skin of the human palm. Therefore in this work the combination of the two methods is used: a grid is heated by the irradiation of the gas-discharge lamp and a grid heats the surface of the finger which is pressed to a grid

    The Role of Outer Membrane Vesicles of Agents of Particularly Dangerous Infections in the Pathogenesis and Immunogenesis of Infectious Process

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    The literature review is devoted to the modern concepts of the vesiculation phenomenon and its biological role in pathogenic bacteria – causative agents of particularly dangerous human infections. Data on the production, structure, composition, and functions of the outer membrane vesicles (OMV) of bacteria have been summarized. In recent years, the interest of researchers in the formation of spherical structures (so called bubbles or vesicles) from outer membrane of gram-negative bacteria has significantly increased. Such structures are surrounded by the double layer of a phospholipid membrane, the outer layer of which is enriched with lipopolysaccharide molecules. The inner space of vesicles could include various antigens, receptors, adhesins, toxins, enzymes, porins, etc. The formation of vesicles by the outer membranes of bacteria is recognized as a normal physiological manifestation of bacterial activity aimed at adaptation to environmental conditions. The investigation of the biological role of OMV showed their connection with the pathogenesis and immunogenesis of bacterial diseases. The review provides information on the peculiarity of induction, OMV composition and their participation in the processes of patho- and immunogenesis of severe infections caused by groups I–II PBA – the gram-negative causative agents of plague, tularemia, brucellosis, glanders, melioidosis, cholera, and formation of extracellular vesicles in a gram-positive anthrax pathogen. The particular attention is paid to the issue of developing safe and effective next-generation vaccine preparations based on bacterial vesicles

    Novel cerium-containing layered double hydroxid

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    Nickel-aluminum-cerium layered double hydroxide (LDH) in carbonate form was successfully synthesized by co-precipitationfollowed by hydrothermal treatment. The predetermined molar percentage was the following: Ni²+/( Al³+ + Ce³+) = 3 and Ce³+/( Al³+ + Ce³+) = 0.05. The XRD data indicated that the cerium-containing single-phase product with a hydrotalcite structure could be obtained by hydrothermal treatment for 48 h at 120 °
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