148 research outputs found
Studying the specific features of the hydration processes of alumina cements based on the compounds of CaO–NiO–Al₂O₃ system
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
Measurement of the electric dipole moments for transitions to rubidium Rydberg states via Autler-Townes splitting
We present the direct measurements of electric-dipole moments for
transitions with for Rubidium atoms. The
measurements were performed in an ultracold sample via observation of the
Autler-Townes splitting in a three-level ladder scheme, commonly used for
2-photon excitation of Rydberg states. To the best of our knowledge, this is
the first systematic measurement of the electric dipole moments for transitions
from low excited states of rubidium to Rydberg states. Due to its simplicity
and versatility, this method can be easily extended to other transitions and
other atomic species with little constraints. Good agreement of the
experimental results with theory proves the reliability of the measurement
method.Comment: 12 pages, 6 figures; figure 6 replaced with correct versio
REGIONAL FEATURES OF BIFIDOBACTERIA ANTAGONISTIC ACTIVITY IN INTESTINAL MICROBIOTA OF CHILDREN LIVING IN SIBERIA
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
Measurement of the 6s - 7p transition probabilities in atomic cesium and a revised value for the weak charge Q_W
We have measured the 6s - 7p_{1/2,3/2} transition probabilities in atomic
cesium using a direct absorption technique. We use our result plus other
previously measured transition rates to derive an accurate value of the vector
transition polarizability \beta and, consequently, re-evaluate the weak charge
Q_W. Our derived value Q_W=-72.65(49) agrees with the prediction of the
standard model to within one standard deviation.Comment: 4 pages, 2 figure
Correlated many-body treatment of Breit interaction with application to cesium atomic properties and parity violation
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 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.
VAGINAL MICROECOLOGY IN WOMEN WITH THE NON-SPECIFIC GENITAL INFLAMMATORY DISEASES AND REPRODUCTIVE FUNCTION DISORDERS
We conducted the microbiological examination of vaginal microbiota in 324 women with non-specific inflammatory diseases of the genital tract and with reproductive dysfunction. According the condition of microecological balance of indigenous microflora (lactobacilli concentration) of women we have identified three types of vaginal microbiota: "normocenosis", " dysbiosis", "deep dysbiosis" We marked deficiency oflactobacilli in every fourth women (28%) with infertility and miscarriage, and deep deficit in every second (53% in the third group) - sharp depression of the indigenous microbiota and its replacement by opportunistic (facultative anaerobic and obligate anaerobic), what indicates microecological trouble in the vaginal biotope and can be one of the causes of infectious and inflammatory diseases of genitals and other reproductive disorders. It was shown that the dominant microorganisms of pathogenic microbiota (UPM) of inflammatory diseases in women are coagulase-negative staphylococci (CNS), fungi of genus Candida, Escherihia coli and Enterococcus spp. During the analysis of UPM representatives material of groups with "normocenosis", "dysbiosis" and "deep dysbiosis" an important microecological indicator was calculated which characterizing microbiocaenosis as a whole - index of species richness (ISR) - the average number of species in the composition
MICROECOLOGICAL AND GENESPECIFIC CHARACTERISTICS OF VAGINAL BIOTOPE LACTOBACILLI IN WOMEN WITH NONSPECIFIC LOWER FEMALE REPRODUCTIVE TRACT INFLAMMATORY DISEASES
The study included 30 reproductive age women with lower female reproductive tract nonspecific inflammatory diseases. The analysis of the qualitative and quantitative pathogenic microorganisms as well as lactobacilli composition was conducted. It was shown that in women observed the opportunistic microflora detected often (73,3 %) in the rest part of patients (26,7 %) in case if opportunistic microflora was absent the disbiotic changes occurred in lower concentration of normal microflora of vagina represented mostly by lactoflora. Deficiency of lactobacilli was observed almost in all women of this group (96,6 %) and only in one case (3,4 %) the concentration of lactobacilli was consistent with normal physiological range. Molecular genetic methods (PCR amplification) with visualization by means of electrophoresis in agarose gel was made for identification of Lactobacilli species. Consistency index (c) and species saturation index (sri) for opportunistic microorganisms in women vaginal biotope examined were calculated. Prevalence of Lactobacillus plantarum and Lactobacillus jensoni isolating in 83 and 50 % respectively was shown. Also it was shown that in the structure of quantitative compatibility of studied species of lactobacilli the highest rate is characterized to the association of two types that makes 53 %
DETECTION OF CERTAIN GENETIC MARKERS OF THE PATHOGENIC FACTORS IN AUTOSTRAINS KLEBSIELLA SPP. IN INFANTS
The article presents the results of detection of genetic determinants of pathogenicity in 44 strains of Klebsiella (Klebsiella pneumoniae, Klebsiella oxytoca), isolated from the intestinal habitat of infants with intestinal dysbiosis. The presence of the uge gene was detected in 92 % of cases in K. oxytoca and in 90 % of K. pneumoniae. Kfu gene was detected twice as frequent (30 %) in K. pneumoniae strains than in K. oxytoca (12,5 %); bfp gene was detected in K. oxytoca 5 times more frequently (25 %) than in K. pneumoniae (5 %), as well as stx 1 - 29,2 % and 15 %, correspondingly. The presence of stx 2 gene wasn't recorded in any of the DNA samples. Registration of investigated determinants in DNA of Klebsiella spp. autostrains which are non-clinical isolates indicates pathogenicity factors circulation among them and therefore the risk of the formation of intestinal dysbiosis in children
Detection of genetic markers of pathogenicity factors at associative symbiosis of Klebsiella spp. and Staphylococcus aureus autostrains, isolated from infants
The article presents the results of detection of genetic determinants of pathogenicity in 120 Klebsiella strains (Klebsiella pneumoniae, Klebsiella oxytoca) and 48 Staphylococcus aureus strains isolated from the intestinal habitat of infants with intestinal dysbiosis. Registration of the investigated determinants in Klebsiella spp. autostrains DNA, which are non-clinical isolates, indicates the circulation of pathogenicity factors and, consequently, their possible causation in the formation of intestinal dysbiosis in infants
Calculations of parity nonconserving s-d transitions in Cs, Fr, Ba II, and Ra II
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.
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