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Immunohistochemical and biochemical study of infiltrative ductal breast carcinoma and tissue adjacent to the tumour revealed a particular molecular profile and characteristics of the oxidant-antioxidant status neoplasms depending on the age of the patients and the presence of metastases in regional lymph nodes. Some causes of high aggressiveness and low hormone sensitivity of tumours in premenopausal women, as well as stability and high metastatic potential of tumours in postmenopausal women have been found. [ABSTRACT FROM AUTHOR]

An experimental batch of connecting M12 bolts for aerospace application was produced by the method of rapid heat treatment with hot heading from the rods of VT22 alloy obtained as a result of intense hot plastic deformation (step-by-step forging and rolling). After final aging in the course of tensile tests, the bolts had the following characteristics: the yield and ultimate strengths equal to 1380 and 1455 МРа, respectively, a relative elongation of 7.2%, and a relative narrowing of 24.3%. The tests carried out according to the program developed at the 'ANTONOV' State Enterprise showed that the fatigue and low-cycle fatigue are almost two times higher in the case of thread rolling performed in the completely thermally hardened state, i.e., after final aging. We also established the possibility of enhancement of the fatigue characteristics of the bolts by improving the technology of mechanical treatment. [ABSTRACT FROM AUTHOR]

The goal of this study is to investigate experimentally the mechanical contact properties of fine particles ( $$<$$ 120 $$\upmu $$ m) using of a novel experimental setup. On the basis of deformation curves from compression tests, particle behaviour under mechanical stress can be approximated with theoretical contact models. Models examined in this study include Walton and Braun, Tomas and Antonyuk, Zener and Thornton. Influence of climatic conditions on particle behaviour as well as hardening effects related to cyclic loading were also considered. Maltodextrin was used as a model substance for primary particles, while irregular shaped titanium dioxide granules were used to study the behaviour of agglomerates. In both cases, results are in good agreement with the established theories. [ABSTRACT FROM AUTHOR]

This article analyzes the stability of solutions of stochastic dynamic systems with the entire prehistory and Markov disturbance. A theorem on sufficient conditions of the asymptotic stochastic stability of solutions of such dynamic systems is formulated and proved. [ABSTRACT FROM AUTHOR]

It has been observed that the Acinetobacter calcoaceticus K-4 strain produces surface-active substances (SAS) while growing either on hydrophilic (ethanol) or on hydrophobic substrates (hexadecane). Maximal SAS synthesis (with a conditional SAS concentration of 3.6; emulsifying activity of culture liquid dissolved in 50 times equal to 96%) was detected with growth on an ethanol-containing medium with the addition of urea, yeast autolysate and microelements, C/N ratio 60:1 and 10% inoculate, cultivated on ethanol-containing medium by the end of the exponential phase of growth. With respect to its chemical nature, extracellular SAS synthesized by A. calcoaceticus K-4 growing on ethanol-containing medium under optimal cultivating conditions form a glycolipid-aminolipid complex. [ABSTRACT FROM AUTHOR]

The Markov properties of the solutions of Ito-Skorokhod stochastic functional-differential equations (SFDEs) with entire prehistory are considered, the concept of a weak infinitesimal operator is introduced for a Markov process that is a solution of an SFDE, and the strong solution of the SFDE is analyzed for stability. [ABSTRACT FROM AUTHOR]

It is shown that the mechanical properties and structure of semifinished products of VT22 alloy are formed in the stage of hot deformation and depend on the kinetics and morphology of formation of the structure. It is shown that the α-edge and α-precipitates affect the properties of semifinished products of VT22 alloy, especially in the case of massive products, which means that the indicated structural inhomogeneities should be regulated by the technical specifications for supply and inspection. [ABSTRACT FROM AUTHOR]

The article presents the study that examines the effect of thermal treatment on the resistance of forge-rolled plates made of high-strength T110 titanium alloy. Macrofractographic investigations of the specimens indicates that the cracks formed due to impacts propagate primarily in the direction of forge-rolling. Moreover, data of the optical and electron fractography of some areas of the surface cracks formed as a result of impacts reveals that the fracture surfaces have pit structure.

The three-dimensional structure of the complex of the enzyme SAICAR synthase with the product of the enzymatic reaction, SAICAR, was solved and refined by methods of protein crystallography. The SAICAR-binding site in the active site of the enzyme was found. The amino-acid residues providing the binding of the reaction product with the protein were revealed. These residues were compared with those involved in the substrate binding in the complex with AICAR and succinic acid studied earlier. [ABSTRACT FROM AUTHOR]

On the basis of the accumulated experimental data on the redistribution of alloying elements between the α-and β-phases in the process of phase transformation and the well-known concept of necessity of guaranteeing equal molybdenum equivalents in the cast state in different parts of the grains in the β-phase, which is attained by complex alloying of titanium with β-stabilizing elements whose distribution coefficients are greater and lower than one, we choose an alloying complex and specify its limits ensuring the high strength and good weldability of the material. On the basis of the Ti-Al-Mo-V-Nb-Fe-Zr system, we propose the composition of a new high-strength titanium alloy with good weldability and develop new modes of its hot deformation, welding, and thermal treatment. [ABSTRACT FROM AUTHOR]

Fatigue tests of welded specimens made of experimental T110 titanium alloy have shown that joints made by electron-beam welding possess the highest endurance under cyclic loading. They have a small zone of thermal influence and finer grain sizes than after argon-arc welding. [ABSTRACT FROM AUTHOR]

The activity and selectivity of mono- and bimetallic catalysts containing copper and rhenium on sibunite were studied in the decomposition of methanol to methyl formate (MF), water, H2, CO, and CO2at 200—400 °C. Methane is also formed on rhenium-containing catalysts at 300—400 °C. The dehydrogenating activity and selectivity to form MF are higher on the copper-sibunite catalysts than on the rhenium-sibunite samples. The introduction of 0.25% Re into the 4% copper-containing catalyst enhances its total activity and stability. [ABSTRACT FROM AUTHOR]

The three-dimensional structures of two enzyme–substrate complexes of SAICAR synthase from the yeast Saccharomycescerevisiae with adenosinetriphosphate (ATP) prepared under different conditions were studied by X-ray diffraction analysis and then refined. An enzyme molecule was shown to contain two binding sites of ATP. One of these sites is located in the central cavity of the enzyme molecule and apparently binds the ATP molecule directly involved in the enzymatic reaction. In the complexes, the phosphate groups of ATP occupying this site adopt different conformations depending on the Mg[sup 2+] concentration. The functional role of the second binding site located at a distance of approximately 15 Å from the first site away from the central enzyme cavity has not been understood as yet. It might be that the second site perform the regulatory role in enzyme functioning. © 2001 MAIK “Nauka / Interperiodica”. [ABSTRACT FROM AUTHOR]

The crystal structures of two forms of the enzyme dimanganese catalase from ThermusThermophilus (native and inhibited by chloride) were studied by X-ray diffraction analysis at 1.05 and 0.98 Å resolution, respectively. The atomic models of the molecules were refined to the R factors 9.8 and 10%, respectively. The three-dimensional molecular structures are characterized in detail. The analysis of electron-density distributions in the active centers of the native and inhibited enzyme forms revealed that the most flexible side chains of the amino acid residues Lys162 and Glu36 exist in two interrelated conformations. This allowed us to obtain the structural data necessary for understanding the mechanism of enzymatic activity of the dimanganese catalase. © 2000 MAIK “Nauka / Interperiodica”. [ABSTRACT FROM AUTHOR]

Methanol decomposition in a water–methanol equimolar mixture is studied in the presence of a nickel-promoted copper–zinc–cement catalyst. Methanol decomposition at 200–300°C on the oxide and reduced forms of the catalyst yields a gas with an H2/CO ratio close to two. The use of an equimolar CH3OH–H2O mixture under analogous conditions enables obtaining gaseous products with a hydrogen concentration up to 75 vol %. [ABSTRACT FROM AUTHOR]