105 research outputs found

    ELECTROCHEMICALLY MEDIATED OXIDATIVE C-C AND C-HET COUPLING

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    ELECTROCHEMICAL OXIDATIVE C-C COUPLING

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    This work was supported by the Russian Science Foundation, project # 21-13-00205

    Basic principles of postgrowth annealing of CdTe:Cl ingot to obtain semi-insulating crystals

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    The process of annealing of a CdTe:Cl ingot during its cooling after growth was studied. The annealing was performed in two stages: a high-temperature stage, with an approximate equality of chlorine and cadmium vacancy concentrations established at the thermodynamic equilibrium between the crystal and vapors of volatile components, and a low-temperature stage, with charged defects interacting to form neutral associations. The chlorine concentrations necessary to obtain semi-insulating crystals were determined for various ingot cooling rates in the high temperature stage. The dependence of the chlorine concentration [Cl+Te] in the ingot on the temperature of annealing in the high-temperature stage was found. The carrier lifetimes and drift mobilities were obtained in relation to the temperature and cadmium vapor pressure in the postgrowth annealing of the ingot.Comment: 6 pages, 6 figure

    Oxetane-containing metabolites: origin, structures, and biological activities

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    Cyclobutanes containing one oxygen atom in a molecule are called oxetane-containing compounds (OCC). More than 600 different OCC are found in nature; they are produced by microorganisms, and also found in marine invertebrates and algae. The greatest number of them is found in plants belonging to the genus Taxus. Oxetanes are high-energy oxygen-containing nonaromatic heterocycles that are of great interest as new potential pharmacophores with a significant spectrum of biological activities. The biological activity of OCC that is produced by bacteria and Actinomycetes demonstrates antineoplastic, antiviral (arbovirus), and antifungal activity with confidence an angiogenesis stimulator, respiratory analeptic, and antiallergic activity dominate with confidence from 81 to 99%

    Stabilized Phase Variants of <I>Vibrio cholerae</I> El Tor P-18895

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    Produced have been stabilized phase variants of V. cholerae El Tor P-18895 (O- and rugose colonies). Frequency of reversion to initial ST-phenotype does not exceed 10 %. Identity of the origin is verified in VNTR. Evaluated has also been their activity by means of the following diagnostic tests: agglutination assay, sensitivity to diagnostic bacteriophages test, and studies of growth behavior in solid nutrient media. Stabilized variants of V. cholerae El Tor P-18895 can be deployed for further investigations of peculiarities of biofilm formation on various surfaces, bacterial resistance to environmental factors, and for the enhancement of methods for isolation of cholera vibrio variants from ambient environment

    Electroproduction of Charmonia off Nuclei

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    In a recent publication we have calculated elastic charmonium production in ep collisions employing realistic charmonia wave functions and dipole cross sections and have found good agreement with the data in a wide range of s and Q^2. Using the ingredients from those calculations we calculate exclusive electroproduction of charmonia off nuclei. Here new effects become important, (i) color filtering of the c-cbar pair on its trajectory through nuclear matter, (ii) dependence on the finite lifetime of the c-cbar fluctuation (coherence length) and (iii) gluon shadowing in a nucleus compared to the one in a nucleon. Total coherent and incoherent cross sections for C, Cu and Pb as functions of s and Q^2 are presented together with some differential cross sections. The results can be tested with future electron-nucleus colliders or in peripheral collisions of ultrarelativistic heavy ions.Comment: 21 pages of Latex including 14 figures; few misprints are fixe

    Lewis Acids and Heteropoly Acids in the Synthesis of Organic Peroxides

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    Organic peroxides are an important class of compounds for organic synthesis, pharmacological chemistry, materials science, and the polymer industry. Here, for the first time, we summarize the main achievements in the synthesis of organic peroxides by the action of Lewis acids and heteropoly acids. This review consists of three parts: (1) metal-based Lewis acids in the synthesis of organic peroxides; (2) the synthesis of organic peroxides promoted by non-metal-based Lewis acids; and (3) the application of heteropoly acids in the synthesis of organic peroxides. The information covered in this review will be useful for specialists in the field of organic synthesis, reactions and processes of oxygen-containing compounds, catalysis, pharmaceuticals, and materials engineering

    Diffractive S and D-wave vector mesons in deep inelastic scattering

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    We derive helicity amplitudes for diffractive leptoproduction of the S and D wave states of vector mesons. We predict a dramatically different spin dependence for production of the S and D wave vector mesons. We find very small R=σL/σTR=\sigma_{L}/\sigma_{T} and abnormally large higher twist effects in production of longitudinally polarized D-wave vector mesons.Comment: 6 pages, 1 Postscript figure; the missing figure include

    Experience in the Design and Production of Recombinant Oral Vaccine «Revax VZT»

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    Objective of the work was the production of recombinant vaccine «RevaxVZT» in tablet dosage form against hepatitis B and pathogenic for humans orthopoxviruses for further clinical trials. Materials and methods. Recombinant strain b7.5S2-S of vaccinia virus carrying a DNA fragment of hepatitis B virus inserted into thymidinekinase gene was used as an active component of the vaccine. Microbiological, virological, physical, physical and chemical, and biotechnological methods were used for studying the quality of the drug and technological processes. Results and discussion. Results of technological control for semi-finished products and final products of the vaccine “Revax VZT” showed the possibility of using certified hardware-processing line of “TEOVac” for its manufacturing. Same technology can be potentially used with other live tableted embryo smallpox vaccines too. For the development of the vaccine “Revax VZT” with the specific activity of not less than 1.0·107 PFu/tablet, it is necessary to use a dry virus-containing material with activity not less than 2.0·108 PFU/g which is produced by freeze-drying of liquid virus-containing preparation with the activity of not less than 1.0·108 PFU/g, preferentially propagated from chorionic allantoic membranes of chicken embryos as a substrate for viral biomass accumulation

    Charm and Bottom Semileptonic Decays

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    We review the present status of theoretical attempts to calculate the semileptonic charm and bottom decays and then present a calculation of these decays in the light--front frame at the kinematic point q2=0q^2=0. This allows us to evaluate the form factors at the same value of q2q^2, even though the allowed kinematic ranges for charm and bottom decays are very different. Also, at this kinematic point the decay is given in terms of only one form factor A0(0)A_{0}(0). For the ratio of the decay rates given by the E653 collaboration we show that the determination of the ratio of the Cabibbo--Kobayashi--Maskawa (CKM) matrix elements is consistent with that obtained from the unitarity constraint. At present, though, the unitarity method still has greater accuracy. Since comparisons of the semileptonic decays into ρ\rho and either electrons or muons will be available soon from the E791 Fermilab experiment, we also look at the massive muon case. We show that for a range of q2q^2 the SU(3)FSU(3)_F symmetry breaking is small even though the contributions of the various helicity amplitudes becomes more complicated. For BB decays, the decay BKˉB \rightarrow K^{*} \ell \bar{\ell} at q2=0q^2=0 involves an extra form factor coming from the photon contribution and so is not amenable to the same kind of analysis, leaving only the decay BKννˉB \rightarrow K^{*}\nu \bar{\nu} as a possibility. As the mass of the decaying particle increases we note that the SU(3)SU(3) symmetry becomes badly broken at q2=0q^2=0.Comment: Latex, 19 pages, two figures are attached, a minor change in the manuscript related to thi
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