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  • 1
    Language: English
    In: Journal of Engineering Physics and Thermophysics, 2012, Vol.85(2), pp.423-431
    Description: With the aim of developing a new methodology of thermal investigations of heat-insulating structures and materials, the features of quasi-stationary heat conduction in a flat wall under varying ambient conditions have been considered. The quasi-stationary approximation errors and the applicability criteria of stationary relations between the thermal parameters of the medium imposing restrictions on the rate of change in boundary temperatures have been determined. The possibility of using nonstationary states and stable conditions in thermal diagnostics of exterior walls has been shown.
    Keywords: heat conduction in a flat wall ; variable boundary conditions ; stationary relations ; thermal parameters ; thermal diagnostics
    ISSN: 1062-0125
    E-ISSN: 1573-871X
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  • 2
    In: Molecular Microbiology, March 2010, Vol.75(6), pp.1389-1401
    Description: Mechanisms of hydrogen peroxide generation in were investigated using a strain lacking scavenging enzymes. Surprisingly, the deletion of many abundant flavoenzymes that are known to autoxidize did not substantially lessen overall HO formation. However, HO production diminished by 25–30% when NadB turnover was eliminated. The flavin‐dependent desaturating dehydrogenase, NadB uses fumarate as an electron acceptor in anaerobic cells. Experiments showed that aerobic NadB turnover depends upon its oxidation by molecular oxygen, with HO as a product. This reaction appears to be mechanistically adventitious. In contrast, most desaturating dehydrogenases are associated with the respiratory chain and deliver electrons to fumarate anaerobically or oxygen aerobically without the formation of toxic by‐products. Presumably, NadB can persist as an HO‐generating enzyme because its flux is limited. The anaerobic respiratory enzyme fumarate reductase uses a flavoprotein subunit that is homologous to NadB and accordingly forms substantial HO upon aeration. This tendency is substantially suppressed by cytochrome oxidase. Thus cytochrome oxidase, which is prevalent among anaerobes, may diminish intracellular HO formation by the anaerobic respiratory chain, whenever these organisms encounter oxygen. These two examples reveal biochemical and physiological arrangements through which evolution has minimized the rate of intracellular oxidant formation.
    Keywords: Hydrogen Peroxide -- Physiological Aspects ; Escherichia Coli -- Physiological Aspects ; Cytochrome Oxidase -- Physiological Aspects;
    ISSN: 0950-382X
    E-ISSN: 1365-2958
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  • 3
    Language: English
    In: Journal of Alloys and Compounds, Oct 5, 2015, Vol.645, pp.S140-S143
    Description: To link to full-text access for this article, visit this link: http://dx.doi.org/10.1016/j.jallcom.2015.01.131 Byline: K.V. Korshunov, M.V. Tsarev, V.V. Mokrushin, A.M. Shapovalov, E.V. Zabavin Abstract: * The method of impedance measurement of powder materials is developed. * Impedance spectroscopy was used to study titanium hydride powders oxidized by air oxygen at different modes. * Impedance spectroscopy seems suitable for studying of properties of shielding coatings at the particles.
    Keywords: Spectroscopy ; Powders (Particulate Matter)
    ISSN: 0925-8388
    Source: Cengage Learning, Inc.
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  • 4
    Language: English
    In: Queueing Systems, 2011, Vol.68(3), pp.261-266
    Description: We discuss the problem of establishing an upper bound for the distribution tail of the stationary waiting time D in the GI / GI /1 FCFS queue.
    Keywords: FCFS single server queue ; Stationary waiting time ; Heavy tails ; Large deviations ; Long tailed distribution ; Subexponential distribution ; Integrated tail distribution ; Accuracy of approximation ; Lower and upper bounds
    ISSN: 0257-0130
    E-ISSN: 1572-9443
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  • 5
    In: Circulation, 2012, Vol.126(20), pp.2418-2427
    Description: BACKGROUND—: Carotid intima-media thickening is associated with increased cardiovascular risk in humans. We discovered that intima formation and cell proliferation in response to carotid injury is greater in SJL/J (SJL) in comparison with C3HeB/FeJ (C3H/F) mice. The purpose of this study was to identify candidate genes contributing to intima formation. METHODS AND RESULTS—: We performed microarray and bioinformatic analyses of carotid arteries from C3H/F and SJL mice. Kyoto Encyclopedia of Genes and Genomes analysis showed that the ribosome pathway was significantly up-regulated in C3H/F in comparison with SJL mice. Expression of a ribosomal protein, RpL17, was 〉40-fold higher in C3H/F carotids in comparison with SJL. Aortic vascular smooth muscle cells from C3H/F grew slower in comparison to SJL. To determine the role of RpL17 in vascular smooth muscle cell growth regulation, we analyzed the relationship between RpL17 expression and cell cycle progression. Cultured vascular smooth muscle cells from mice, rats, and humans showed that RpL17 expression inversely correlated with growth as shown by decreased cells in S phase and increased cells in G0/G1. To prove that RpL17 acted as a growth inhibitor in vivo, we used pluronic gel delivery of RpL17 small interfering RNA to C3H/F carotid arteries. This resulted in an 8-fold increase in the number of proliferating cells. Furthermore, following partial carotid ligation in SJL mice, RpL17 expression in the intima and media decreased, but the number of proliferating cells increased. CONCLUSIONS—: RpL17 acts as a vascular smooth muscle cell growth inhibitor (akin to a tumor suppressor) and represents a potential therapeutic target to limit carotid intima-media thickening.
    Keywords: Medicine ; Anatomy & Physiology;
    ISSN: 0009-7322
    E-ISSN: 15244539
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  • 6
    Language: English
    In: The Physics of Metals and Metallography, 2013, Vol.114(9), pp.789-797
    Description: The effect of a thermomechanical treatment including severe plastic deformation under dry sliding friction conditions and subsequent heating in air to 350–650°C with further holding for 1 h on the structure and wear resistance of commercial titanium of grade VT1-0 has been studied. It has been shown that the deformation by friction leads to the formation of a nanocrystalline structure with α crystals 20–100 nm in size in a surface layer of titanium of about 10 μm thick. The heating of titanium deformed by friction at temperatures of 450–650°C for 1 h in air leads to the formation in the surface layer of this material ∼10 μm thick of nanocrystalline particles of the titanium oxide TiO 2 (rutile), the volume fraction of which reaches tens of percents, while the dimensions are ∼10 nm. The presence in the surface layer of titanium of a nanocrystalline two-phase (α-Ti + rutile) structure leads to a significant increase in the wear resistance of the VT1-0 titanium in pair with steel 40Kh13. This is explained by the enhanced strength of the arising nanocrystalline layer and its positive influence (as of a transition layer) on the reduction of the level of internal stresses that exist at the interface between the titanium oxide TiO 2 and the host metal.
    Keywords: deformation by friction ; heating ; nanocrystalline layer ; TiO (rutile) particles ; tribological properties
    ISSN: 0031-918X
    E-ISSN: 1555-6190
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  • 7
    In: Nature, 2013, Vol.497(7451), p.624
    Description: Recent exon-sequencing studies of human tumours have revealed that subunits of BAF (mammalian SWI/SNF) complexes are mutated in more than 20% of all human malignancies, but the mechanisms involved in tumour suppression are unclear. BAF chromatin-remodelling complexes are polymorphic assemblies that use energy provided by ATP hydrolysis to regulate transcription through the control of chromatin structure and the placement of Polycomb repressive complex 2 (PRC2) across the genome. Several proteins dedicated to this multisubunit complex, including BRG1 (also known as SMARCA4) and BAF250a (also known as ARID1A), are mutated at frequencies similar to those of recognized tumour suppressors. In particular, the core ATPase BRG1 is mutated in 5-10% of childhood medulloblastomas and more than 15% of Burkitt's lymphomas. Here we show a previously unknown function of BAF complexes in decatenating newly replicated sister chromatids, a requirement for proper chromosome segregation during mitosis. We find that deletion of Brg1 in mouse cells, as well as the expression of BRG1 point mutants identified in human tumours, leads to anaphase bridge formation (in which sister chromatids are linked by catenated strands of DNA) and a G2/M-phase block characteristic of the decatenation checkpoint. Endogenous BAF complexes interact directly with endogenous topoisomerase IIα (TOP2A) through BAF250a and are required for the binding of TOP2A to approximately 12,000 sites across the genome. Our results demonstrate that TOP2A chromatin binding is dependent on the ATPase activity of BRG1, which is compromised in oncogenic BRG1 mutants. These studies indicate that the ability of TOP2A to prevent DNA entanglement at mitosis requires BAF complexes and suggest that this activity contributes to the role of BAF subunits as tumour suppressors.
    Keywords: Antigens, Neoplasm -- Metabolism ; DNA Helicases -- Metabolism ; DNA Topoisomerases, Type II -- Metabolism ; DNA, Catenated -- Chemistry ; DNA-Binding Proteins -- Metabolism ; Nuclear Proteins -- Metabolism ; Transcription Factors -- Metabolism;
    ISSN: 0028-0836
    E-ISSN: 14764687
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  • 8
    Language: English
    In: Journal of Engineering Physics and Thermophysics, 2014, Vol.87(4), p.827(12)
    Description: Systematizing the partial solutions of the nonstationarity heat conduction problem of a flat wall in comparison with the general asymptotic solution of this problem, we have found the transverse temperature distributions with any monotone change in the ambient conditions and elucidated the heat conduction properties of the wall under these conditions. The asymptotic solution is given by semiconvergent series and definite integrals and has been investigated for power time dependences with an exponent of 0-2, which has enabled us to justify the concept of quasi-stationarity of the thermal parameters of the wall and obtain asymptotic errors and corrections defining the deviations of these parameters from their stationary values. The features of the average heat flows most resistant to thermal disturbances as to both time and amplitude have been considered. Keywords: heat conduction of a flat wall, variable boundary conditions, asymptotic dependences, quasi-stationarity, heat flow density.
    Keywords: Engineering ; Engineering Thermodynamics, Heat and Mass Transfer ; Thermodynamics ; Industrial Chemistry/Chemical Engineering ; Statistical Physics, Dynamical Systems and Complexity ; Mechanics ; Heat Conduction of a Flat Wall ; Variable Boundary Conditions ; Asymptotic Dependences ; Quasi-Stationarity ; Heat Flow Density ; Engineering ; Physics;
    ISSN: 1062-0125
    E-ISSN: 1573871X
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  • 9
    In: Molecular Microbiology, July 2016, Vol.101(1), pp.62-77
    Description: When sulfur compounds are scarce or difficult to process, adapts by inducing the high‐level expression of sulfur‐compound importers. If cystine then becomes available, the cystine is rapidly overimported and reduced, leading to a burgeoning pool of intracellular cysteine. Most of the excess cysteine is exported, but some is adventitiously degraded, with the consequent release of sulfide. Sulfide is a potent ligand of copper and heme moieties, raising the prospect that it interferes with enzymes. We observed that when cystine was provided and sulfide levels rose, became strictly dependent upon cytochrome oxidase for continued respiration. Inspection revealed that low‐micromolar levels of sulfide inhibited the proton‐pumping cytochrome oxidase that is regarded as the primary respiratory oxidase. In the absence of the back‐up cytochrome oxidase, growth failed. Exogenous sulfide elicited the same effect. The potency of sulfide was enhanced when oxygen concentrations were low. Natural oxic‐anoxic interfaces are often sulfidic, including the intestinal environment where dwells. We propose that the sulfide resistance of the cytochrome oxidase is a key trait that permits respiration in such habitats. Toxic levels of intracellular sulfide arise either from the degradation of excess cysteine or from an influx of hydrogen sulfide itself. Sulfide inhibits the primary respiratory cytochrome oxidase, and continued respiration depends upon the presence of the secondary cytochrome oxidase. This scenario is likely common to sulfidic environments, such as the mammalian gut.
    Keywords: Sulfur Compounds ; Cytochromes ; Heme ; Respiration ; Enzymes ; Copper ; Hydrogen Sulfide ; Habitat ; Sulfide ; Oxygen ; Digestive Tract ; Cysteine ; Intestine ; Cytochrome Bd ; Escherichia Coli ; Cell Biology;
    ISSN: 0950-382X
    E-ISSN: 1365-2958
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  • 10
    Language: English
    In: Journal of Alloys and Compounds, 05 October 2015, Vol.645, pp.S140-S143
    Description: Results of studies of current-conducting properties of titanium hydride powders oxidized by air oxygen at different modes in order to form oxide and oxohydride coatings at the particles surface which enhance heat resistance of the hydride are presented. Method of impedance spectroscopy is used to determine contribution of resistance of the formed coatings and contribution of resistance of the grains of titanium hydride powders into the powder impedance. Method aspects of conducting measurements of the impedance of powder materials by stepwise sample compression are discussed. General approach to experimental data processing related to study of metal hydrides which contain shielding films of various chemical compositions at the particle surface is described.
    Keywords: Titanium Hydride Powder ; Impedance Spectroscopy of Powder Materials ; Stepwise Compression ; Interparticle Contacts ; Shielding Coatings At the Particle Surface ; Engineering ; Chemistry ; Physics
    ISSN: 0925-8388
    E-ISSN: 1873-4669
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