MATHEMATICS
For sufficiently large Q there exist the intervals I ⊂ [0,1) of length c1(n)Q−1 that do not contain algebraic numbers of any degree n and of height H(P) ≤ Q. In this article we have found an condition for intervals I in terms of the Diophatine approximations when the intervals of length c2(n)Q−γ, γ >1, contain not less than c3(n)Qn−2γ+1 algebraic numbers α of height H(α) ≤ Q and degree deg α = n > 2γ -1.
PHYSICS
CHEMISTRY
In this paper, the effect of brassinosteroids – 24-epibrassinolide and 28-homocastasterone, as well as their stereoisomers – (22S,23S)-24-homobrassinolide and (22S,23S)-28-homocastasterone on the level of reactive oxygen species in cancer cell line A549 (lung adenocarcinoma) has been characterized for the first time, and the results obtained have been compared with the data on their antiproliferative activity.
The effect depended on the structure of the side chain and was more pronounced in the case of the SS-orientation of hydroxyl groups at the C22 and C23 positions ((22S,23S)-28-homocastasterone). This compound also had greater antiproliferative activity, which suggested a possible relationship between the induction of activated oxygen species and cytotoxicity of the substances.
The results of this work allow one to assume that one of the ways of the effect of brassinosteroids on cancer cells may lie in the initiation of oxidative stress, which leads to the death of cancer cells through ROS-dependent mechanisms.
BIOLOGY
EARTH SCIENCES
TECHNICAL SCIENCES
The results of investigation of elemental and phase composition, structure, microhardness, and friction coefficient of the Ti-6Al-4V alloy surface layer treated by compression plasma flows are presented. The findings showed that the plasma impact resulted in forming a modified layer with the thickness of up to 24 μm containing δ-TiNx, α′-Ti(N), α-Ti and β-Ti phases. The treatment of the Ti-6Al-4V alloy by compression plasma flows led to a more uniform alloying element distribution in the modified layer and to a decrease of the aluminium concentration. The plasma surface modification allows the surface layer microhardness to be increased by a factor of 1.5 and the friction coefficient to be decreased by a factor of 2 in comparison with the initial sample.
The effect of diisocyanate chain extender (CE) on the rheological, and relaxation properties, as well as on the molecular weight and crystallizability, of poly(butylene terephthalate) (PBT) and thermoplastic polyester elastomer (TPEE) blends with the different-phase structure has been studied. It has been showed that CE in the amount of 0.2 up to 1.25 % leads to an increase in polyesters melt and solutions viscosity because of chain extending and cross-linking reactions. Values of high and low flow limits increase with increasing the CE concentration regardless of the phase structure of blends. It is revealed that СЕ decreases the polyesters melt-crystallization temperature; the crystallinity reduces simultaneously, which is indicative of the crystallization deceleration owing to a growth of the molecular weight.
SOCIAL SCIENCES AND HUMANITIES
On the basis of the concepts of Western scientists Anton Popovich, Katarina Rice, Hans Fermeer, Edmund Husserl, Roman Ingarden et al., hard-to solve problems of literary translation from related languages are comprehended theoretically. The translation is a result of an original work of a translator who reproduces the original in the language of another nationality and for different social and cultural environment and is an indication of certain translation outlook and aesthetic position.
AGRARIAN SCIENCES
ISSN 2524-2431 (Online)