138 research outputs found

    Studying the specific features of the hydration processes of alumina cements based on the compounds of CaO–NiO–Al₂O₃ system

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    The article gives the results of studying hydration processes occurring in cement synthesis using waste products of chemical industry. Cement clinker was synthesized with the relation of initial raw components, calcium-containing water treatment waste and rejected nickel containing catalyst of AZOT Private Joint Stock Company (Severodonetsk, Luhansk Region, Ukraine), equal to 50/50. The obtained samples were studied by Strelkov minor method: normal density, setting time and mechanical strength were determined within 1, 3, 7 and 28 days. The results regarding the setting product were analyzed by differential thermal, X-ray phase analysis, microscopic analysis and electron microscopy; this enables to control the phase relation in the synthesis of a new class of aluminate cements using waste products of chemical industry. The obtained data showed the absence of cubic hydroaluminates which deteriorate the strength. The methods of physicochemical analysis revealed that the phase composition of hydrated alumina cement is represented by calcium hydroaluminate of different basicity, whereas cleavage structure consists of prismatic crystals which give dual coalescence, and this is favorable form to provide matrix self-reinforcement. The developed composition of aluminous nickel-containing cement referred to hydraulic binders. The results of physical-mechanical tests of the synthesized cements indicated that the obtained cements are quick-setting, fast-hardening and high-strength materials

    Phase and Intensity Distributions of Individual Pulses of PSR B0950+08

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    The distribution of the intensities of individual pulses of PSR B0950+08 as a function of the longitudes at which they appear is analyzed. The flux density of the pulsar at 111 MHz varies strongly from day to day (by up to a factor of 13) due to the passage of the radiation through the interstellar plasma (interstellar scintillation). The intensities of individual pulses can exceed the amplitude of the mean pulse profile, obtained by accumulating 770 pulses, by more than an order of magnitude. The intensity distribution along the mean profile is very different for weak and strong pulses. The differential distribution function for the intensities is a power law with index n = -1.1 +- 0.06 up to peak flux densities for individual pulses of the order of 160 Jy

    Pharmacological characteristics of intranasal dosage forms containing Ginkgo biloba extracts

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    To evaluate specific pharmacological activity of the developed dosage forms of ginkgo bilob

    REGIONAL FEATURES OF BIFIDOBACTERIA ANTAGONISTIC ACTIVITY IN INTESTINAL MICROBIOTA OF CHILDREN LIVING IN SIBERIA

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    Antagonistic properties of bifidobacteria to opportunistic microorganisms in vitro and mechanism of antagonistic activity decreasing were studied and. analyzed. Great percentage of bifidobacteria regional population strains with low antagonistic activity to transitional opportunistic microorganisms is registered. It results to colonization. resistance decreasing and. requires development of the preventive probiotics therapy methods to correct

    Analysis of phagoand antibiotic sensitivity of Enterobacteriaceae bacteria isolated from women of reproductive age

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    Pelvic inflammatory diseases occupy a special place in the structure of general morbidity, and are polymicrobial in nature with dominance of opportunistic microorganisms, in particular bacteria of the family Enterobacteriaceae. The aim was to study the composition of the vaginal microbiota in women of reproductive age with pelvic inflammatory diseases, as well as to determine the sensitivity of isolated microorganisms to antibiotics and bacteriophages. The study included 70 women of reproductive age, among them 37 were diagnosed with colpitis and cervicitis, 33 women in the comparison group (women screened for a diagnosis). Isolated microorganisms were identified by abdominoperineal methods, including the disk diffusion method to determine the sensitivity of microorganism cultures of Enterobacteriaceae family to antibiotics, and the method of crosses (evaluation of lytic activity of bacteriophages by the number of crosses) to determine the sensitivity to specific therapeutic bacteriophages. Vaginal biocenosis was characterized by deficit of lactobacilli (< 106 CFU/ml in 100 %), the presence of conditionally pathogenic microflora: bacteria of Enterobacteriaceae family, coccal flora and Candida fungi. From 60.0 to 89.3 % of Enterobacteria strains were resistant to aminoglycosides and quinolones, but also had a low level of sensitivity to therapeutic bacteriophages. The obtained data indicate the reduction of colonization resistance of vaginal mucosa in pelvic inflammatory diseases and specify the need to use medicinal drugs only under medical supervision to prevent clinically significant drug resistance

    Calculations of parity nonconserving s-d transitions in Cs, Fr, Ba II, and Ra II

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    We have performed ab initio mixed-states and sum-over-states calculations of parity nonconserving (PNC) electric dipole (E1) transition amplitudes between s-d electron states of Cs, Fr, Ba II, and Ra II. For the lower states of these atoms we have also calculated energies, E1 transition amplitudes, and lifetimes. We have shown that PNC E1 transition amplitudes between s-d states can be calculated to high accuracy. Contrary to the Cs 6s-7s transition, in these transitions there are no strong cancelations between different terms in the sum-over-states approach. In fact, there is one dominating term which deviates from the sum by less than 20%. This term corresponds to an s-p_{1/2} weak matrix element, which can be calculated to better than 1%, and a p_{1/2}-d_{3/2} E1 transition amplitude, which can be measured. Also, the s-d amplitudes are about four times larger than the corresponding s-s transitions. We have shown that by using a hybrid mixed-states/sum-over-states approach the accuracy of the calculations of PNC s-d amplitudes could compete with that of Cs 6s-7s if p_{1/2}-d_{3/2} E1 amplitudes are measured to high accuracy.Comment: 15 pages, 8 figures, submitted to Phys. Rev.

    CENTRE OF ISOTOPIC AND GEOCHEMICAL RESEARCH (IGC SB RAS): CURRENT STATE OF MICRO- AND MACROANALYSIS

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    Centre of Isotopic and Geochemical Research based on the Analytical Department of Vinogradov Institute of Geochemistry SB RAS (Irkutsk) performs a wide range of analytical studies to solve mineralogical and petrological, geochemical, prospecting, ecological, paleoclimatic and applied problems. The studies are supported by the modern equipment for electron microprobe, X-ray diffraction, X-ray fluorescence, atomic emission and mass spectrometric (including isotope) analyses, as well as the necessary international certified reference materials (SRM) and a collection of SRM of the natural and technogenic composition of our production

    MICROECOLOGICAL CHARACTERISTICS OF KLEBSIELLA SPP. REGIONAL POPULATIONS IN THE INTESTINAL MICROBIOTA OF IRKUTSK CHILDREN

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    In this paper the microecological characteristics of Klebsiella spp. regional populations in the intestinal microbiota of infants were represented. 373 children (55,9 % of general quantity of researched) had disbiotic changes of intestinal microbiota related to increasing number of Klebsiella. The autostrains sensitivity to antibiotic drugs (в-lactams, aminoglycosides, quinolones) and to purified Klebsiella pneumoniae phage and purified polyvalent Klebsiella phage were researched. Samples of isolates (n = 142) characterized by a high proportion of antibiotic susceptible strains. Phage sensitivity of bacteriophage to the commercial preparations was determined in 268 strains of Klebsiella spp. of two types (146 strains of K. Oxytoca and 122 strains of K. pneumonia). Probably high frequency of pathogens resistant to studied bacteriophages (K. oxytocain 66 % and K. pneumoniae in 77.8 % of cases) was the reason of low efficiency of phage therapy by specific phage and can explain high frequency of occurrence of Klebsiella at dysbiosis in children of early age

    Species substrate specificity of growth of lactobacilli isolated from vaginal biotope on culture medium with inclusions of different types of natural nanopolysaccharides

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    The article presents the research of substrate and prebiotic properties of natural nanopolysaccharides for several species of lactobacilli isolated from vaginal biotope of women, with assessment of their species combinations. Most of typeable lactobacilli species prefer to grow on media containing polysaccharides, mainly in nutrient broth supplemented with galactomannan and carageenan. Using galactomannan increases the frequency of detection, as compared with the isolation from the starting material, twice

    Correlated many-body treatment of Breit interaction with application to cesium atomic properties and parity violation

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    Corrections from Breit interaction to basic properties of atomic 133Cs are determined in the framework of third-order relativistic many-body perturbation theory. The corrections to energies, hyperfine-structure constants, off-diagonal hyperfine 6S-7S amplitude, and electric-dipole matrix elements are tabulated. It is demonstrated that the Breit corrections to correlations are comparable to the Breit corrections at the Dirac-Hartree-Fock level. Modification of the parity-nonconserving (PNC) 6S-7S amplitude due to Breit interaction is also evaluated; the resulting weak charge of 133^{133}Cs shows no significant deviation from the prediction of the standard model of elementary particles. The neutron skin correction to the PNC amplitude is also estimated to be -0.2% with an error bound of 30% based on the analysis of recent experiments with antiprotonic atoms. The present work supplements publication [A. Derevianko, Phys. Rev. Lett. 85, 1618 (2000)] with a discussion of the formalism and provides additional numerical results and updated discussion of parity violation.Comment: 16 pages; 5 figs; submitted to Phys. Rev.
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