1,477 research outputs found

    К актуальности разработки информационных систем для поддержки социальных исследований

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    This article is devoted to the problem of social researches information support and designed for the purpose of weaknesses identification in the current methods of organizing large-scale sociological studies (within the region) and also for assessment of related costs

    Characterization of the monocyte-specific esterase (MSE) gene

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    Carboxylic esterases are widely distributed in hematopoietic cells. Monocytes express the esterase isoenzyme (termed 'monocyte-specific esterase', MSE) that can be inhibited by NaF in the alpha-naphthyl acetate cytochemical staining. We examined the expression of MSE in normal cells and primary and cultured leukemia-lymphoma cells. The MSE protein was demonstrated by isoelectric focusing (IEF); MSE mRNA expression was investigated by Northern blotting and reverse transcriptase-polymerase chain reaction (RT-PCR). The following samples were positive for MSE protein and Northern mRNA expression: 20/24 monocytic, 4/32 myeloid, and 1/20 erythroid-megakaryocytic leukemia cell lines, but none of the 112 lymphoid leukemia or lymphoma cell lines; of the normal purified cell populations only the monocytes were positive whereas, T, B cells, and granulocytes were negative; of primary acute (myelo) monocytic leukemia cells (CD14-positive, FAB M4/M5 morphology) 14/20 were Northern mRNA and 11/14 IEF protein positive. RT-PCR revealed MSE expression in 29/49 Northern-negative lymphoid leukemia-lymphoma cell lines. The RT-PCR signals in monocytic cell lines were on average 50-fold stronger than the mostly weak trace expression in lymphoid specimens. On treatment with various biomodulators, only all-trans retinoic acid significantly upregulated MSE message and protein levels but could not induce new MSE expression in several leukemia cell lines; lipopolysaccharide and interferon-gamma increased MSE expression in normal monocytes. Analysis of DNA methylation with sensitive restriction enzymes showed no apparent regulation of gene expression by differential methylation; the MSE gene is evolutionarily conserved among mammalian species; the half-life of the human MSE transcripts was about 5-6 h. The extent of MSE expression varied greatly among different monocytic leukemia samples. However, the MSE overexpression in a significant number of specimens was not associated with gene amplification, gross structural rearrangements or point mutations within the cDNA region. Taken together, the results suggest that MSE expression is not absolutely specific for, but strongly associated with cells of the monocytic lineage; MSE is either not expressed at all or expressed at much lower levels in cells from other lineages. The biological significance, if any, of rare MSE messages in lymphoid cells detectable only by the hypersensitive RT-PCR remains unclear. Further studies on the regulation of this gene and on the physiological function of the enzyme will no doubt be informative with respect to its striking overexpression in some malignant cells and to a possible role in the pathobiology of monocytic leukemias

    Hydrogen fluoride and inorganic fluorine compounds (fluorides) – Addendum: Evaluation of a pregnancy risk group for the BAT value

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    In 2005, the German Commission for the Investigation of Health Hazards of Chemical Compounds in the Work Area re-evaluated the maximum workplace concentration (MAK value) of hydrogen fluoride [7664-39-3] and fluorides [16984-48-8]. If the MAK values of 1 ml hydrogen fluoride/m3 (0.83 mg/m3) or 1 mg fluoride/m3, respectively, are not exceeded, prenatal toxic effects are not to be expected. Therefore, hydrogen fluoride and fluorides were classified in Pregnancy Risk Group C. In 2013, the biological tolerance value (BAT value) for hydrogen fluoride and inorganic fluorine compounds (fluorides) of 4 mg fluoride/l urine was established which protects against the long-term effects of fluoride such as skeletal fluorosis. The BAT value was not derived in correlation to the MAK value. For this reason, it is to be evaluated whether no prenatal toxic effects are to be expected when the BAT value is adhered to. By extrapolating the NOAEL (no observed adverse effect level) for developmental toxicity in rodent studies to fluoride concentrations in urine it could be concluded that Pregnancy Risk Group C is also valid for the BAT value

    Magnetoplasmon excitations in an array of periodically modulated quantum wires

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    Motivated by the recent experiment of Hochgraefe et al., we have investigated the magnetoplasmon excitations in a periodic array of quantum wires with a periodic modulation along the wire direction. The equilibrium and dynamic properties of the system are treated self-consistently within the Thomas-Fermi-Dirac-von Weizsaecker approximation. A calculation of the dynamical response of the system to a far-infrared radiation field reveals a resonant anticrossing between the Kohn mode and a finite-wavevector longitudinal excitation which is induced by the density modulation along the wires. Our theoretical calculations are found to be in excellent agreement with experiment.Comment: 9 pages, 8 figure

    Features of financing of small business and microenterprises

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    In this article, we examined the specifics of financing small businesses and microenterprises

    Optical excitations of a self assembled artificial ion

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    By use of magneto-photoluminescence spectroscopy we demonstrate bias controlled single-electron charging of a single quantum dot. Neutral, single, and double charged excitons are identified in the optical spectra. At high magnetic fields one Zeeman component of the single charged exciton is found to be quenched, which is attributed to the competing effects of tunneling and spin-flip processes. Our experimental data are in good agreement with theoretical model calculations for situations where the spatial extent of the hole wave functions is smaller as compared to the electron wave functions.Comment: to be published in Physical Review B (rapid communication

    Fragmentation pathways of nanofractal structures on surface

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    We present a detailed systematical theoretical analysis of the post-growth processes occurring in nanofractals grown on surface. For this study we developed a method which accounts for the internal dynamics of particles in a fractal. We demonstrate that particle diffusion and detachment controls the shape of the emerging stable islands on surface. We consider different scenarios of fractal post-growth relaxation and analyze the time evolution of the island's morphology. The results of our calculations are compared with available experimental observations, and experiments in which the post-growth relaxation of deposited nanostructures can be probed are suggested.Comment: 34 pages, 11 figure
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