Reagent Separation of Petroleum-containing Plant Sludges and Sediments

More than 7 million tons of petroleum sludges formed in circulating water systems as a result of treatment of wastewaters, maintenance of equipment, and cleaning of tanks has accumulated in enterprises in the oil production, oil refining, and petrochemical industry, and in tank farms [1].     

Transverse spatial transport in field-effect transistors based on heterostructures with selective doping and the limits of applicability of quasi-hydrodynamic models

Semiconductors - For field-effect transistors based on heterostructures with selective doping, the results of calculations for the output characteristics of devices on the basis of the hydrodynamic...     

SBA-15 modified with Al,Ti, or Zr as supports for highly active NiW catalysts for HDS

A series of SBA-15-type materials modified with Al, Ti, and Zr were prepared and used as supports for hydrodesulfurization (HDS) catalysts based on NiW. Prepared supports and catalysts were characterized by N₂ physisorption, small- and wide-angle XRD, UV–Vis DRS, FT-IR, IEP, TPR, TPD, HRTEM, and SEM–EDX. Sulfided catalysts were evaluated in HDS of dibenzothiophene (DBT). Catalytic activity tests show that the creation of defined anchoring points for the W species by modifying the surface of SBA-15 with Al, Ti, and Zr results in a considerable improvement in catalysts’ performance compared to pure SBA-supported analog. The possible reasons for this behavior are discussed.     

Laser sintering of ultradispersed iron-base powder materials

Experimental data on the formation of the structure and mechanical properties of layers produced from ultradispersed Fe-base powder mixtures under laser irradiation (λ ∼ 1 μm) with a radiation density q ∼ 10³ W/cm² and pulse duration 10⁻⁵ s are reported. The results of the study provide a background for the development of a method of producing complex metal alloys in a metastable condition with the help of high-concentration energy sources. The field of application of this method is the production of thin layers on the surface of highly loaded friction units.     

Influence of bioactive dietary supplement--dietary unsaturated fats--on immune status of patients with myocardial ischemia and impaired glucose tolerance

Immune status measured by the flow cytrometric analysis under the ischemic heart disease and IHD with impaired glucose tolerance has been found to be altered in B cells as well as in T lymphocytes in some cases. Having received the diet supplemented by PUFA "Eicolen", IHD patients present with the restored immune status. Patients with IHD and impaired glucose tolerance did not present with any significant modifications in immune status after PUFA "Eicolen" supplementation.     

Structural flexibility of the linker region of human P-glycoprotein permits ATP hydrolysis and drug transport

P-Glycoprotein (Pgp), an energy-dependent drug efflux pump responsible for multidrug resistance of many cancer cells, is comprised of two homologous halves connected by a peptide segment approximately 75 amino acids (aa) in length. The effects of length and composition of this connecting region on Pgp cell surface expression and the ability of the two halves to interact were explored using both stable transfections of Pgp mutants in mammalian cell lines and a vaccinia virus transient expression system. A 17 aa insertion of predicted flexible structure between amino acids 681 and 682 resulted in a functional Pgp molecule that was capable of conferring drug resistance. In contrast, an 18 aa peptide insertion with a predicted alpha-helical structure was unstable when expressed transiently. A 34 aa deletion from the central core of the linker region (Delta653-686) resulted in a protein expressed at the cell surface in amounts comparable to that of wild-type Pgp but unable to confer drug resistance. No apparent differences in drug or [alpha-32P]-8-azido-ATP photoaffinity labeling were observed. However, both ATP hydrolysis and drug transport activities of the deletion mutant were completely abrogated, indicating that the linker deletion disconnected substrate binding from ATP hydrolysis and transport. This mutant also failed to exhibit an ATP hydrolysis-dependent enhancement of binding of a conformation-sensitive monoclonal antibody, UIC2. Upon replacement with a 17 aa linker peptide having a predicted flexible secondary structure, but bearing no homology to the deleted 34 aa segment, normal Pgp transport and basal and drug-stimulated ATPase activities were restored along with increased UIC2 binding in the presence of substrate, suggesting a dramatic conformational change between the nonfunctional and functional molecules. Taken together, these data suggest a flexible secondary structure of the connector region is sufficient for the coordinate functioning of the two halves of Pgp, likely specifically required for the proper interaction of the two ATP binding sites.