Effect of basicity and chromium oxide on the viscosity of boron-containing slags

The main diluent for chromium-containing slags is CaF2. However, fluorspar disadvantages make it necessary to search for a replacement. As a substitute, boron oxide allows to improve slag physical properties and environmental situation. The paper presents the experimental study results of the chemical composition and temperature influence on viscosity of slags of CaO-SiO2-Cr2O3 system containing 8% MgO, 3% Al2O3 and 6% B2O3. It was found that a slag free of chromium oxide with basicity of 1.0 has a sufficiently high fluidity of 0.2-0.6 Pa•s in a wide temperature range of 1200-1350 C, due to high concentration of low-melting phases, reaching 22%, and only 11 % high-melting. A slag with 18% Cr2O3 and the same basicity retains a low viscosity of 0.1-1.0 Pa•s but at higher temperature of 1450-1570 C due to increase in high-melting compound content to 27%. The viscosity of a slag with basicity of 2.5 without chromium oxide is 0.07-1.0 Pa•s in a narrow temperature range of 1650-1700 C and 0.14-1.0 Pa•s for a 'shorter' slag with 18% Cr2O3 and same basicity in even narrower range of 1650-1670 C. These slags have the highest high-melting phase content of about 50%. © Published under licence by IOP Publishing Ltd

Профилактика профессиональных заболеваний работающего населения

The article discusses urgent issues of maintenance, possible risks of occupational diseases, adoption of measures to optimize and improve the quality of working conditions, exchanging of experience with other countries, necessity to monitor the health status of employees and mandatory medical check-ups, the adoption of universal terminology and classification of occupational diseases, longer life expectancy resulted in later retirement age. The article describes some forms of work, danger and harmfulness of the working environment. The article is based on legal safety guidelines, it the importance of the employment contract between employees and employers, the state policy directions in the field of occupational safety. The article also contains information on special assessment of working conditions (a study of harmful and hazardous production factors).В статье «Профилактика профессиональных заболеваний работающего населения» поднимаются актуальные вопросы о сохранении здоровья населения, о возможных рисках профзаболеваний, принятие мер по оптимизации и улучшению качества условий труда, обмен опытом с другими странами, необходимость мониторинга состояния здоровья работающих, обязательные медицинские осмотры работников, принятие единой терминологии и классификации профзаболеваний, увеличение пенсионного возраста, как результат продолжительности жизни и здоровья нации. Описаны некоторые виды трудовой деятельности, опасность и вредность производственной среды. За основу взяты правовые источники охраны труда, необходимость и важность трудового договора между работником и работодателем, направления государственной политики в области охраны труда. Также дана информация по специальной оценке условий труда (исследование вредных и опасных производственных факторов)

Excitons in type-II quantum dots: Finite offsets

Quantum size effects for an exciton attached to a spherical quantum dot are calculated by a variational approach. The band line-ups are assumed to be type-II with finite offsets. The dependence of the exciton binding energy upon the dot radius and the offsets is studied for different sets of electron and hole effective masses

Relation Between the Thickness of Stellar Disks and the Relative Mass of Dark Halo in Galaxies

We consider a thickness of stellar disks of late-type galaxies by analyzing the R and K_s band photometric profiles for two independent samples of edge-on galaxies. The main goal is to verify a hypotesis that a thickness of old stellar disks is related to the relative masses of the spherical and disk components of galaxies. We confirm that the radial-to-vertical scale length ratio for galactic disks increases (the disks become thinner) with the increasing of total mass-to-light ratio of the galaxies, which characterize the contribution of dark halo to the total mass, and with the decreasing of central deprojected disk brightness (surface density). Our results are in good agreement with numerical models of collisionless disks evolved from subcritical velocity dispersion state to a marginally stable equilibrium state. This suggests that in most galaxies the vertical stellar velocity dispersion, which determine the equilibrium disk thickness, is close to the minimum value, that ensures disk stability. The thinnest edge-on disks appear to be low brightness galaxies (after deprojection) in which a dark halo mass far exceeds a mass of the stellar disk.Comment: 13 pages. To be Published in Astronomy Letters, v.28(2002

Mechanisms of the Vertical Secular Heating of a Stellar Disk

We investigate the nonlinear growth stages of bending instability in stellar disks with exponential radial density profiles.We found that the unstable modes are global (the wavelengths are larger than the disk scale lengths) and that the instability saturation level is much higher than that following from a linear criterion. The instability saturation time scales are of the order of one billion years or more. For this reason, the bending instability can play an important role in the secular heating of a stellar disk in the $z$ direction. In an extensive series of numerical $N$-body simulations with a high spatial resolution, we were able to scan in detail the space of key parameters (the initial disk thickness $z_0$, the Toomre parameter $Q$, and the ratio of dark halo mass to disk mass $M_{\rm h} / M_{\rm d}$). We revealed three distinct mechanisms of disk heating in the $z$ direction: bending instability of the entire disk, bending instability of the bar, and heating on vertical inhomogeneities in the distribution of stellar matter.Comment: 22 pages including 8 figures. To be published in Astronomy Letters (v.29, 2003

Genome sequence of the Trifolium rueppellianum -nodulating Rhizobium leguminosarum bv. trifolii strain WSM2012

Rhizobium leguminosarum bv. trifolii WSM2012 (syn. MAR1468) is an aerobic, motile, Gram-negative, non-spore-forming rod that was isolated from an ineffective root nodule recovered from the roots of the annual clover Trifolium rueppellianum Fresen. growing in Ethiopia. WSM2012 has a narrow, specialized host range for N2-fixation. Here we describe the features of R. leguminosarum bv. trifolii strain WSM2012, together with genome sequence information and annotation. The 7,180,565 bp high-quality-draft genome is arranged into 6 scaffolds of 68 contigs, contains 7,080 protein-coding genes and 86 RNA-only encoding genes, and is one of 20 rhizobial genomes sequenced as part of the DOE Joint Genome Institute 2010 Community Sequencing Progra

Ultrathin compound semiconductor on insulator layers for high performance nanoscale transistors

Over the past several years, the inherent scaling limitations of electron devices have fueled the exploration of high carrier mobility semiconductors as a Si replacement to further enhance the device performance. In particular, compound semiconductors heterogeneously integrated on Si substrates have been actively studied, combining the high mobility of III-V semiconductors and the well-established, low cost processing of Si technology. This integration, however, presents significant challenges. Conventionally, heteroepitaxial growth of complex multilayers on Si has been explored. Besides complexity, high defect densities and junction leakage currents present limitations in the approach. Motivated by this challenge, here we utilize an epitaxial transfer method for the integration of ultrathin layers of single-crystalline InAs on Si/SiO2 substrates. As a parallel to silicon-on-insulator (SOI) technology14,we use the abbreviation "XOI" to represent our compound semiconductor-on-insulator platform. Through experiments and simulation, the electrical properties of InAs XOI transistors are explored, elucidating the critical role of quantum confinement in the transport properties of ultrathin XOI layers. Importantly, a high quality InAs/dielectric interface is obtained by the use of a novel thermally grown interfacial InAsOx layer (~1 nm thick). The fabricated FETs exhibit an impressive peak transconductance of ~1.6 mS/{\mu}m at VDS=0.5V with ON/OFF current ratio of greater than 10,000 and a subthreshold swing of 107-150 mV/decade for a channel length of ~0.5 {\mu}m

Influence of silicone mammoplasty on the immunoendocrine status of female recipients

The article concerns a study of early influence of silicone breast implants on the development of autoimmune reactions and dynamics of prolactin and thyroid hormone levels in women after mammoplasty. At the present time, this issue remains relevant for several reasons: more than 20 million pairs of implants have been installed in the world and the number of their implantations is constantly growing. Despite relative safety of the silicone implants, some of them are periodically banned by regulatory bodies in various countries. At the same time, there is a growing number of controversial publications in the scientific literature, about potential adverse consequences of their use. Some authors suggest an association between the silicone implants and risk of developing autoimmune conditions, connective tissue disorders, and occasional malignancies. On the other hand, the journals are full of publications about the overall safe tolerance of such medical devices by the patients. These considerations served as a pre-requisite to our research. As part of this project, we have assayed serum levels of autoantibodies to ten antigens, as well as contents of prolactin and thyroid hormones by means of ELISA technique in 27 patients before, 3 and 6 months after aesthetic and reconstructive mammoplastics performed within a period of September 2018 to November 2019. As a result, it was found that 5 out of 27 patients exhibited changes in the autoimmunity spectrum and intensity after mammoplasty. In particular, the concentrations of autoantibodies to modified citrullinated vimentin and IgM autoantibodies to cardiolipin exceeded the normal level at 3 and 6 months. In addition, the initially high prolactin concentration in mammoplasty recipients dropped to normal ranges by 3 months after breast surgery, even after several-fold increased initial levels. As for thyroid hormones, there were no statistically significant changes in their dynamics. The increase of autoantibodies to various target antigens after mammoplasty was statistically significant and positively correlated with each other. This can be explained, for example, by dependence on the adjuvant effect of silicone, which is not associated with antigen specificity. However, it may generally stimulate the immune responses

Bending Instability of Stellar Disks: The Stabilizing Effect of a Compact Bulge

The saturation conditions for bending modes in inhomogeneous thin stellar disks that follow from an analysis of the dispersion relation are compared with those derived from $N$-body simulations. In the central regions of inhomogeneous disks, the reserve of disk strength against the growth of bending instability is smaller than that for a homogeneous layer. The spheroidal component (a dark halo, a bulge) is shown to have a stabilizing effect. The latter turns out to depend not only on the total mass of the spherical component, but also on the degree of mass concentration toward the center. We conclude that the presence of a compact (not necessarily massive) bulge in spiral galaxies may prove to be enough to suppress the bending perturbations that increase the disk thickness. This conclusion is corroborated by our $N$-body simulations in which we simulated the evolution of almost equilibrium, but unstable finite-thickness disks in the presence of spheroidal components. The final disk thickness at the same total mass of the spherical component (dark halo + bulge) has been found to be much smaller than that in the simulations where a concentrated bulge is present.Comment: 27 pages including 10 figures. To be published in Astronomy Letters (v.31, No. 1, pp. 15-29 2005

PHENOTYPIC AND FUNCTIONAL CHARACTERISTICS OF MICROVESICLES PRODUCED BY NATURAL KILLER CELLS

Natural killer (NK) cells are of special interest among a multitude of microvesicle (MV) source cells. NK cells are a lymphocyte subpopulation performing contact cytolysis of virus-infected cells and tumor cells. Each of the NK cell populations has a unique receptor repertoire on its surface and, thus, unique functions. During their contact with a target cell, the most common mechanism of cytolysis is an exocytosis of lytic granules. However, some indirect evidence suggests that MV with CD56 phenotype and leukocyte-derived MV with various phenotypes are present in the peripheral blood plasma.This research is aimed to study the phenotype, composition and cytotoxic activity of microvesicles produced by NK cells. The analysis of receptor expression showed that MV, as well as source cells of the NK-92 cell line, had a similar CD56 molecule expression profile. The expression profile in MV differs from the same in source cells by higher CD119 and CD11b expression and by lower CD18 expression. Culturing of NK-92 cells in the presence of PMA, IL-1β, TNFα, IFNγ resulted in alterations of cell phenotypes and MV. Immunoblots revealed a change of perforin and granzyme B (GrB) in MV. The analysis of the cytotoxic activity of NK-92 cells in a natural killer in vitro assay employing K562 target cells demonstrated that MV obtained from TNFα-activated cells of the NK-92 cell line increased the cytotoxicity of the same TNFα-activated NK-92 cells regarding cytotoxicity levels. This coincides with the previously revealed increased content of GrB in MV obtained from TNFα-activated cells of the NK-92 cell line. To sum up depending on the cytokine NK-92 cells produce MV that differ in their phenotype, composition and activity. Any changes in MV composition can result in changes in their functional activity: in particular, changes can increase the cytotoxic activity of NK cells of the NK-92 cell line. Thus, besides a well-known and proved way for GrB delivery to a target cell, we can suggest an additional way – the transportation of GrB within MV