Galvanomagnetic properties of 3C-SiC epilayers grown on hexagonal SiC substrates

Epitaxial 3C-SiC films have been grown on 6H-SiC substrates by sublimation epitaxy in vacuum. The Hall effect in these heterostructures and their magnetoresistance have been measured in a temperature range from 1.4 to 300 K. At liquid-helium temperatures, the samples are characterized by low resistance and exhibit negative magnetoresistance in weak fields (～1 T). Analysis of the experimental results suggests that the low resistance of samples is most probably due to the metal-insulator transition in the epitaxial 3C-SiC films.     

Bounds for the number of modes of the simplest Gaussian mixture

Several theorems on sufficient unimodality conditions are formulated for a sum of k normal distributions with the same variance and with different mean values μ _i , i = 1, ..., k, 2 ≤ k < ∞, taken with their a priori probabilities π_i. On the basis of these theorems, estimates for the lower and upper bounds for the mode numbers m are obtained for k ≥ 3 in the case when the mixture contains k* components, 2 ≤ k* < k, satisfying the unimodality conditions. Aprausheva Nina Nikolaevna (b. 1940). Graduated from the Moscow State University (Department of Mechanics and Mathematics) in 1966. In 1982, defended the Cand. Sci. thesis “On the Application of Mixtures of Normal Distributions in Pattern Recognition.” Senior scientist at Dorodnicyn Computing Center, Russian Academy of Sciences. Scientific interests: mathematical statistics, computational mathematics, mathematical methods in pattern recognition, and decision theory (about 70 publications). Member of Association of Pattern Recognition. Mollaverdi Naser (b. 1967). Graduated from the Isfahan University of Technology (Iran) in 1990. In 1995, graduated from the Educational University (Teheran, Iran). Third-year scholar at Moscow State University (Department of Computational Mathematics and Cybernetics). Scientific interests: computational mathematics, pattern recognition, programming, and statistics (12 publications). Sorokin Stanislav Viktorovich (b. 1947). Graduated from Moscow State University (Department of Computational Mathematics and Cybernetics) in 1971. Programmer at Dorodnicyn Computing Center, Russian Academy of Sciences. Scientific interests: computational mathematics, system programming, and pattern recognition (15 publications).     

Structural strength of frozen soils during thawing

Conclusions Frozen clayey soils of semi-hard and hard consistency and sandy soils of medium density have a structural strength equal to the value of the actual pressure under complete saturation, and, consequently, the suspending effect of water, and their deformation is determined by the presence of ice striations and the extent to which the macropores that form after their complete thawing are interconnected. From The Editorial Office: Problems that are extremely interesting from the scientific and practical standpoint are touched upon in the paper. The authors, however, do not always adequately substantiate their own assumptions. Making note of the influence exerted by the suspending action of water on the settlement of frozen soils, the authors fail to cite data on comparison of the results of settlement computation with allowance for and with disregard of the suspending effect of water and actual settlement; this would impart greater persuasiveness to their assumptions. The authors' conclusions on the structural strength of soils are also insufficiently founded — neither physicomechanical characteristics of the soils under consideration nor geologic sections are cited, and there is no comparison made between computed and actual settlements.By publishing the paper "in order of discussion," therefore, the editorial office hopes that other specialists will participate in the solution of these critical problems.Translated from Osnovaniya, Fundamenty i Mekhanika Gruntov, No. 5, pp. 17–18, September–October, 1989.     

hTERT-Driven Immortalization of RDEB Fibroblast and Keratinocyte Cell Lines Followed by Cre-Mediated Transgene Elimination

The recessive form of dystrophic epidermolysis bullosa (RDEB) is a crippling disease caused by impairments in the junctions of the dermis and the basement membrane of the epidermis. Using ectopic expression of hTERT/hTERT + BMI-1 in primary cells, we developed expansible cultures of RDEB fibroblasts and keratinocytes. We showed that they display the properties of their founders, including morphology, contraction ability and expression of the respective specific markers including reduced secretion of type VII collagen (C7). The immortalized keratinocytes retained normal stratification in 3D skin equivalents. The comparison of secreted protein patterns from immortalized RDEB and healthy keratinocytes revealed the differences in the contents of the extracellular matrix that were earlier observed specifically for RDEB. We demonstrated the possibility to reverse the genotype of immortalized cells to the state closer to the progenitors by the Cre-dependent hTERT switch off. Increased β-galactosidase activity and reduced proliferation of fibroblasts were shown after splitting out of transgenes. We anticipate our cell lines to be tractable models for studying RDEB from the level of single-cell changes to the evaluation of 3D skin equivalents. Our approach permits the creation of standardized and expandable models of RDEB that can be compared with the models based on primary cell cultures.     

Pre-Senescence Induction in Hepatoma Cells Favors Hepatitis C Virus Replication and Can Be Used in Exploring Antiviral Potential of Histone Deacetylase Inhibitors

Recent evidence suggests that fibrotic liver injury in patients with chronic hepatitis C correlates with cellular senescence in damaged liver tissue. However, it is still unclear how senescence can affect replication of the hepatitis C virus (HCV). In this work, we report that an inhibitor of cyclin-dependent kinases 4/6, palbociclib, not only induced in hepatoma cells a pre-senescent cellular phenotype, including G1 arrest in the cell cycle, but also accelerated viral replicon multiplication. Importantly, suppression of HCV replication by direct acting antivirals (DAAs) was barely affected by pre-senescence induction, and vice versa, the antiviral activities of host-targeting agents (HTAs), such as inhibitors of human histone deacetylases (HDACi), produced a wide range of reactions—from a dramatic reduction to a noticeable increase. It is very likely that under conditions of the G1 arrest in the cell cycle, HDACi exhibit their actual antiviral potency, since their inherent anticancer activity that complicates the interpretation of test results is minimized.     

Production of high-alumina cement clinker by fusion in an electric furnace

Conclusions The possibility of obtaining clinker from high-alumina cement by melting a mixture of lime and technical alumina in an electric-arc furnace at the Klyuchevsk Ferroalloy Plant has been shown.The high-alumina cement obtained from fused clinker is significantly better in its physicochemical properties than the cement produced on the basis of the lime-alumina slags from the ferroalloy industry.Translated from Ogneupory, No. 5, pp. 25–27, May, 1984.     

Crust formation in the blast-furnace stack

Conclusions It was established that the crust forming on the lining of the blast-furnace stack can be divided into two genetic varieties, viz., mass-exchange and metallurgical crusts.The formation of a mass-exchange crust on the stack lining must be prevented by constructing the lining of high-density, thermally and chemically stable refractory minerals. At the same time it is advantageous to create conditions which favor the formation of a protective metallurgical crust on the surface of the lining.Translated from Ogneupory, No, 2, pp. 39–42, February, 1976.