564 research outputs found

    Interaction of Gram-negative bacteria with cationic proteins: Dependence on the surface characteristics of the bacterial cell

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    Gram-negative bacteria can enter the bloodstream and interact with serum cationic proteins. The character of interaction will depend on the surface characteristics of bacterial cells, which are determined by bacterial chemotype and density of lipopolysaccharide (LPS) packing in the cell wall. It was shown that the lysozyme treatment resulted in the increase sensitivity to hypotonic shock. Significant differences to this effect were found between Escherichia coli strain D21 and D21f2 under treatment with physiological protein concentration. On the basis of electrokinetic measurements and studies of the interaction of cells with lysozyme, the hypothesis was formed that the cell wall of the E. coli strain D21f2 contains more LPS and has a higher density of their packing than the cell wall of the E. coli D21 cells. The effect of lysozyme and lactoferrin on the viability of E. coli cells of two different strains was examined. Lysozyme was found to more effectively inhibit the growth of the E. coli D21 bacteria, and lactoferrin suppressed mainly the growth of the E. coli D21f2 bacteria. These results indicate that the differences in LPS core structure of bacterial R-chemotype, which determines surface charge and density of LPS packing, plays an essential role in the mechanisms of interaction of the cationic proteins with the cell wall

    Long-range angular correlations on the near and away side in p–Pb collisions at

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    Underlying Event measurements in pp collisions at s=0.9 \sqrt {s} = 0.9 and 7 TeV with the ALICE experiment at the LHC

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    Evaluating the potential of capillary rise for the migration of Pt nanoparticles in Luvisols and Phaeozems (Western Siberia)

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    Numerous experiments with nanoparticles have recently led to a better understanding of the migration of colloids and larger particles in soils. However, it remains unclear how colloidal particles migrate in soil horizons without macropores, and whether they can move with the fl ow of capillary water. In this article, we tested the hypothesis that colloidal particles can be transported by water flow in capillary-sized soil pores. To test our hypothesis, column experiments with platinum nanoparticles were carried out. The columns contained undisturbed monoliths from the Luvisols and Phaeozems soil horizons in the southeast of Western Siberia. The lower part of the soil columns was immersed in a colloidal solution with platinum nanoparticles. Thus, we checked whether the nanoparticles would rise to the top of the columns. Platinum nanoparticles are a usable tracer of colloidal particle migration pathways. Due to the minimal background concentrations, platinum can be detected by inductively coupled plasma mass spectrometry (ICP-MS) in experimental samples. Due to their low zeta potential, nanoparticles are well transported over long distances through the pores. Our experiments made it possible to establish that the process of the transfer of nanoparticles with a fl ow of capillary water is possible in almost all the studied horizons. However, the transfer distances are limited to the fi rst tens of centimeters. The number of migrating nanoparticles and the distance of their transfer increase with an increase in the minimum moisture-holding capacity and decrease with an increase in the bulk density of soil horizons and an increase in the number of direct macropores. The migration of nanoparticles in capillary pores is limited in carbonate soil horizons. The transfer of colloidal particles through soil capillaries can occur in all directions, relative to the gravity gradient. Capillary transport plays an important role in the formation of the ice composition of permafrost soils, as well as in plant nutrition

    Transformations of Conjugated Enynones in the Superacid CF<sub>3</sub>SO<sub>3</sub>H. Synthesis of Butadienyl Triflates, Indanones, and Indenes

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    Conjugated 1,5-diarylpent-2-en-4-yn-1-ones add the superacid CF<sub>3</sub>SO<sub>3</sub>H to the acetylenic bond with formation of the corresponding butadienyl triflates. Under superacidic reaction conditions, these triflates are transformed into indanone or indene derivatives depending on which substituents on the aromatic ring are conjugated with the butadiene fragment. In a less acidic system (10% vol pyridine in CF<sub>3</sub>SO<sub>3</sub>H) only the formation of butadienyl triflates takes place. Cationic reaction intermediates were studied by means of NMR and DFT calculations

    Analysis of Energy and Power Parameters on the Extruding of Copper Installation Conform with Prechamber

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    Объектом расчета послужил реальный технологический процесс непрерывного экструдирования медных профилей на установке «Конформ», оснащенной комплектом прессового инструмента с форкамерой на заводе по обработке цветных металлов в городе Каменск-Уральский. Для расчета длины разъемного контейнера, которая должна обеспечить на его подвижной поверхности силу трения, достаточную для экструдирования металла из форкамеры в очко матрицы, крутящего момента на приводном колесе и мощности электродвигателя, использована методика, основанная на определении полного усилия прессования, которая была предложена И.Л. Перлиным. Полученные уравнения отличаются простотой и удобством использования при техническом и технологическом проектировании процесса экструдирования металла способом «Конформ» с применением форкамерThe object of the calculation served as a real process of continuous extrusion of copper profiles on the installation Conform equipped with a set of pressing tool prechamber at the factory for processing non-ferrous metals in the city of Kamensk-Uralsk. To calculate the length of the split container, which should provide on its moving surface friction force sufficient to extrude the metal from the forehearth in a point matrix, the torque on the drive wheel and the electric motor power, used a methodology based on the determination of the total compression force, which was proposed by I.L. Perlin. These equations are characterized by simplicity and ease of use in technical and technological design of the metal extrusion process method Conform with prechambe

    Analysis of Energy and Power Parameters on the Extruding of Copper Installation Conform with Prechamber

    Get PDF
    Объектом расчета послужил реальный технологический процесс непрерывного экструдирования медных профилей на установке «Конформ», оснащенной комплектом прессового инструмента с форкамерой на заводе по обработке цветных металлов в городе Каменск-Уральский. Для расчета длины разъемного контейнера, которая должна обеспечить на его подвижной поверхности силу трения, достаточную для экструдирования металла из форкамеры в очко матрицы, крутящего момента на приводном колесе и мощности электродвигателя, использована методика, основанная на определении полного усилия прессования, которая была предложена И.Л. Перлиным. Полученные уравнения отличаются простотой и удобством использования при техническом и технологическом проектировании процесса экструдирования металла способом «Конформ» с применением форкамерThe object of the calculation served as a real process of continuous extrusion of copper profiles on the installation Conform equipped with a set of pressing tool prechamber at the factory for processing non-ferrous metals in the city of Kamensk-Uralsk. To calculate the length of the split container, which should provide on its moving surface friction force sufficient to extrude the metal from the forehearth in a point matrix, the torque on the drive wheel and the electric motor power, used a methodology based on the determination of the total compression force, which was proposed by I.L. Perlin. These equations are characterized by simplicity and ease of use in technical and technological design of the metal extrusion process method Conform with prechambe

    PNPLA3 rs738409 associates with alcoholic liver cirrhosis but not with serum levels of IL6, IL10, IL8 or CCL2 in the Russian population

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    Introduction and aim: Polymorphic variant rs738409 within the PNPLA3 gene associates with alcoholic liver cirrhosis (ALC) in heavy drinkers of various ancestry but has not yet been established in the Russian population characterized by high incidence of ALC. PNPLA3 rs738409 involvement in the inflammatory process has been proposed as one of the mechanisms of liver dysfunction. Relationship between the PNPLA3 polymorphism and the biochemical markers of inflammation in patients with ALC remains unclear. The current study revealed the association between the rs738409 polymorphism, liver cirrhosis and serum cytokines in heavy drinkers in the Russian population. Materials and methods: The serum levels of IL6, IL10, IL8, and CCL2 along with PNPLA3 rs738409 polymorphism were determined in heavy drinkers (AA, n = 71) and heavy drinkers with diagnosed liver cirrhosis (ALC, n = 110). All of the recruited individuals were Caucasians and belonged to the Russian population. Results: Heavy drinkers carrying PNPLA3 rs738409 CG or CG+GG genotypes as compared with CC genotype carriers or G allele as compared with C allele carriers had significant risk of ALC. In ALC levels of interleukins and CCL2 increased as compared with AA. PNPLA3 rs738409 CC carriers had lower cirrhosis stage as compared with CG+GG carriers, however there were no differences of IL6, IL10, IL8 or CCL2 levels between G allele carriers and non-carriers in heavy drinkers. Conclusion: Thus, in the Russian population heavy drinkers carrying PNPLA3 rs738409 G allele are at higher risk of ALC, however the presence of rs738409 allele does not influence the serum cytokine levels

    Friedel–Crafts Alkylation of Arenes with 2‑Halogeno-2-CF<sub>3</sub>‑styrenes under Superacidic Conditions. Access to Trifluoromethylated Ethanes and Ethenes

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    The formation of the corresponding benzyl cations [ArHC<sup>+</sup>–CH­(X)­CF<sub>3</sub>] takes place under protonation of <i>E</i>-/<i>Z</i>-2-halogeno-2-CF<sub>3</sub> styrenes [ArCHC­(X)­CF<sub>3</sub>, X = F, Cl, Br] in superacids. The structures of these new electrophiles were studied by means of NMR and theoretical DFT calculations. According to these data, in the case of bromo derivatives, the formed cations, most probably, exist as cyclic bromonium ions; however, in the cases of chloro and fluoro derivatives, open forms are more preferable. Subsequent reaction of these benzyl cations with arenes proceeds as Friedel–Crafts alkylation to afford 1,1-diaryl-2-halo-3,3,3-trifluoro­propanes [Ar­(Ar′)­CH–CH­(X)­CF<sub>3</sub>] in high yields (up to 96%) as a mixture of two diastereomers. The prepared halogenopropanes were easily converted into the corresponding mixtures of <i>E</i>-/<i>Z</i>-trifluoro­methylated diarylethenes [Ar­(Ar′)­CCCF<sub>3</sub>] (in yields up to 96%) by dehydrohalogenation with base (KOH or <i>t</i>-BuOK). The mechanism of elimination (E<sub>2</sub> and Ecb) depends on the nature of the leaving group and reaction conditions
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