Sialon-containing silicon carbide refractories

Conclusions We worked out the technology of sialon-containing silicon carbide refractories for lining the shafts of blast furnaces. It was shown that addition of MgO in combination with the waste products of the oxides of the rare-earth elements improves the strength and the other properties of the products fired at 1550°C in nitrogen atmosphere.The sialon-containing silicon carbide refractories exhibit a high resistance to the action of slags and are recommended for lining the lower portion of the shaft and the bosh of blast furnaces.Translated from Ogneupory, No. 5, pp. 6–8, May, 1992.     

Immature Vascular Smooth Muscle Cells in Healthy Murine Arteries and Atherosclerotic Plaques: Localization and Activity

The local development of atherosclerotic lesions may, at least partly, be associated with the specific cellular composition of atherosclerosis-prone regions. Previously, it was demonstrated that a small population of immature vascular smooth muscle cells (VSMCs) expressing both CD146 and neuron-glial antigen 2 is postnatally sustained in atherosclerosis-prone sites. We supposed that these cells may be involved in atherogenesis and can continuously respond to angiotensin II, which is an atherogenic factor. Using immunohistochemistry, flow cytometry, wound migration assay xCELLigence system, and calcium imaging, we studied the functional activities of immature VSMCs in vitro and in vivo. According to our data, these cells do not express nestin, CD105, and the leptin receptor. They are localized in atherosclerosis-prone regions, and their number increases with age, from 5.7% to 23%. Immature VSMCs do not migrate to low shear stress areas and atherosclerotic lesions. They also do not have any unique response to angiotensin II. Thus, despite the localization of immature VSMCs and the presence of the link between their number and age, our study did not support the hypothesis that immature VSMCs are directly involved in the formation of atherosclerotic lesions. Additional lineage tracing studies can clarify the fate of these cells during atherogenesis.     

Mullite-alumina refractories with combined nitride-containing binders

Formation of a combined nitride-containing binder for mullite-alumina refractories is studied. An optimal combination is found to consist of 80% crystalline silicon, 10% silicon carbide, and 10% aluminum, magnium, or zirconium oxide. Mullite-alumina refractories with selected binders showed high resistance to the effects of slag, alkali, and iron.Translated from Ogneupory, No. 6, pp. 9–13, June, 1994.     

Effect of dimensions of the hot conditioning zone on homogenizing capacity of a sheet glass melting furnace

Translated from Steklo i Keramika, No. 2, pp. 12–14, February, 1990.     

High efficiency removal of dissolved As(III) using iron nanoparticle-embedded macroporous polymer composites

Novel nanocomposite materials where iron nanoparticles are embedded into the walls of a macroporous polymer were produced and their efficiency for the removal of As(III) from aqueous media was studied. Nanocomposite gels containing α-Fe₂O₃ and Fe₃O₄ nanoparticles were prepared by cryopolymerisation resulting in a monolithic structure with large interconnected pores up to 100 μm in diameter and possessing a high permeability (ca. 3 × 10⁻³ m s⁻¹). The nanocomposite devices showed excellent capability for the removal of trace concentrations of As(III) from solution, with a total capacity of up to 3 mg As/g of nanoparticles. The leaching of iron was minimal and the device could operate in a pH range 3-9 without diminishing removal efficiency. The effect of competing ions such as SO₄²⁻ and PO₄³⁻ was negligible. The macroporous composites can be easily configured into a variety of shapes and structures and the polymer matrix can be selected from a variety of monomers, offering high potential as flexible metal cation remediation devices.     

Drug resistant tuberculosis in prisons in Azerbaijan: case study

Tuberculosis is a significant health problem in Azerbaijan. In prisons, this problem is compounded by overcrowding, poor general health, a high representation of risk groups, late case finding, and incomplete treatments. The present study investigated the extent of drug resistance at the Central Penitentiary Hospital in Baku--the country's only treatment center for prisoners with tuberculosis. This International Committee of the Red Cross program, established in 1995, uses the directly observed treatment, short course (DOTS) strategy. Sputum samples were collected from two groups of prisoners: 1) 28 patients who failed to respond, clinically or bacteriologically, after a minimum of 8 weeks to the treatment regimen recommended by the World Health Organization and 2) 38 patients consecutively enrolled over a 4-week period from whom sputum was taken before the start of treatment. Mycobacterium tuberculosis was isolated from all 66 sputum specimens. In the first group, 25 strains (98%) were multidrug resistant (to rifampicin and isoniazid). Such resistance occurred in all new cases and 14 (82%) of the 17 failure or relapse cases. In the second group, 9 strains (24%) were multidrug resistant and only 12 (32%) were fully susceptible. This resistance was found in 3 strains (15%) among the 20 new cases and in 6 strains (33%) among the 18 cases of treatment failure or relapse. These findings suggest that prisoners may have an important future role in the transmission of tuberculosis, especially multidrug resistant forms, in the former Soviet Union.     

Morphological effects in rats following a 22-day space flight

A morphological examination of 27 rats flown onboard the biosatellite and sacrificed on the 1st-2nd and 26-27th postflight days demonstrated no significant changes in the structural organization of the vital organs and systems of the animal body. It was, however, found that the space exposure induced morphologically detectable changes in the musculo-skeletal system, hemo- and lymphopoiesis, hypothalamic-pituitary-adrenal system and the juxtaglomerular apparatus of the kidneys. The changes were reversible and nonspecific, and could be seen in animals exposed to ground-based hypokinetic and other stress experiments. Postflight the animals developed some reactions that were similar to those in humans. This helps to identify the morphological substrate of certain changes in the human body and to investigate their pathogenesis.