In this article, upper bounds of spectral radii of K_2,4-minor-free graphs have been obtained.

Functional quadrature formulas for evaluation of mathematical expectation of nonlinear functionals from the solution to the linear Îto–Lévy equation are constructed. The formulas are exact for third-degree functional polynomials from the solution. The error of the constructed composed formula is obtained for a class of integral-form functionals.

In the article, we have obtained an asymptotic formula for the number of algebraic integers α of an arbitrary given degree n that have the height H(α) ≤ Q and lie in the interval I, as Q tends to infninity. We have proved that the error term in this formula is of the order O(Q^n–1) for infinitely many intervals. We have shown that algebraic integers of the given degree n are distributed asymptotically just like algebraic numbers of the degree n – 1.

The generalized two-step Newton–Kantorovich method for approximate solution of nonlinear equations with nondifferentiable operators allowing the separation of a regular smooth component is considered. Using majorants, the convergence of this method is proved and estimates for the convergence rate are obtained.

Within the framework of traditional cosmography (without reference to Friedmann’s cosmological equations) the metric of Robertson-Walker type is found, for which a relationship between conformal and cosmic times coincides in form with the transformation of light cone generating lines with respect to a group of special conformal transformations. The metric gives birth to a constant value of the deceleration parameter equal to minus one second, which reproduces the effect of accelerating expansion of the Universe in good agreement with observations.

It is shown that the effect of synchrotron-like electron-positron pair production by gamma-quanta makes it possible to devise angular-sensitive gamma-telescopes with a resolution of several hundreds microradians to be effective at gamma-quanta energies of several tens of GeV and more. The gamma-telescope angular resolution can be increased up to several tens of microradians if the effect of electron radiative cooling is used. An efficiency of gamma-quanta registration by the proposed crystalline gammatelescopes is close to unity while their mass per 1 m² of active area does not exceed 100 kg, allowing one to devise gammatelescopes with an active area of 10 m².

We discuss the possibility of constructing topological solitons which generalize the Hopfian field configurations in the scalar Faddeev–Skyrme model extended to the case of spaces with the dimensions d = 4n – 1, nєZ. The fields of the model are the Hopf maps φ : R^4n–1 → S²ⁿ with the usual vacuum boundary condition φ(x) → φ₀ as x →∞. These soliton configurations are labelled by the topological invariant Q, which generalizes the first Hopf invariant of the map S³ → S². We have demonstrated that there is a topological energy bound E ≥ c|Q|^d⁄d+1, which generalizes the Vaculenko–Kapitansky inequality.

Within the framework of the density functional theory, the method was developed to calculate the band gap of semiconductors. Calculation of the band gap for a number of monoatomic and diatomic semiconductors demonstrated that the method gives the value of the band gap of almost experimental accuracy. An important point is the fact that the developed method can also be used to calculate both localized states (energy deep-level of defects in crystal), and electronic properties of nanostructures.

The method is developed for a simultaneous differentiation of red blood cells in terms of magnetic susceptibility, hemoglobin oxygenation, and sedimentation velocity based upon video recording and automated handling of cell motion trajectories in a thin microfluidic channel under the action of crossed gravitational and high-gradient magnetic fields. The study of suspension of red blood cells with a low oxygen partial pressure, for the first time, revealed the existence of cell fractions with considerably reduced and increased hemoglobin oxygenation, which is presumably related with a weakened oxygen transport function of old red blood cells. Our method creates additional possibilities of studying native and pathogenic processes in red blood cells, and can be useful for medical diagnostics.

For the first time, reagents have been synthesized and a technique has been developed for a lanthanide immunofluorometric assay of phytohormonal steroids of 24-epicastasterone and 24-epibrassinolide. A low-molecular-weight conjugate of the brassinosteroid and an Eu³⁺ complexonate was synthesized by the reaction of 24-epicastasterone-6-(O-carboxymethyl) oxime N-succinimide ester with the europium salt of the diethylenetriaminepentaacetic acid N¹-(aminoethyl)amide. A protein conjugate with a high specific fluorescent activity was the product of a simultaneous acylation of primary amino groups in albumin with activated esters of carboxyl derivatives of 24-epicastasterone and an Eu³⁺ complexonate. Using the high-molecular weight conjugate in an immunochemical system, a linear relationship was obtained between a fluorescent signal of labeled 24-epiсastasterone bound to immobilized antibodies and 24-epibrassinolide concentration in the range of 1 to 300 nM.

Conformational and energy characteristics of the structural complex between the HIV-1 gp41 protein and monoclonal antibody 10e8 exhibiting broad viral neutralization were studied by molecular dynamics simulations. Contributions of the amino acid residues of the gp41 protein and antibody 10e8 to the enthalpy constituent of the free energy of the complex formation were estimated. Residues Tyr- 99, Asp-100, Phe-100a, Trp-100b of the heavy chain of antibody 10e8 and Trp-672, Phe-673, Arg-683 of the gp41 protein were shown to be critical for the binding. The results obtained form a productive basis for virtual screening, computer testing, and development of novel HIV-1 entry inhibitors presenting the antibody 10e8 peptidomimetics with broad-spectrum neutralizing activity.

A high antimicrobial activity of сarvaсrol, citral, and linalool is confirmed. The features of the antibacterial activity of pinene and limonene enantiomers are determined. A high antimicrobial activity of the essential oils of Satureja montana and Monarda fistulosa regarding test-cultures, which allows one to consider essential oils of these plants as effective antimicrobial agents, is shown.

The possibility of sonochemical immobilization of polymolybdic acid on the surface of electrochemically deposited nickel is shown. It is revealed that the thus obtained oxide-hydroxide surface layer is inhomogeneous and involves the products of interaction of molybdic acid oligomers with nickel and MoO₃ particles which impart antifriction properties to the modified nickel surface. The possibility of doping the sonochemically obtained molybdenum oxide-hydroxide layer with a corrosion inhibitor (benzotriazole) is demonstrated; such treatment results in a radical (ca. 4-fold) enhancement of corrosion resistance of the galvanic nickel coating.

We have studied the dependence of aggregation of mitochondrial aspartate aminotransferase (mAspAT) from the concentration of gold nanoparticles (AuNP). It has been shown that AuNPs decreased the aggregation of mAspAT in the temperature range from 55 to 73 °C. The maximal anti-aggregational effect of AuNP reached 56 % and was observed at 60 °C. Increase of AuNP concentration led to a decrease of the constant rate of enzyme aggregation. We suggest here that interaction between Au-NPs and mAspAT increases conformational stability of the enzyme molecule. It also reduces the probability of polypeptide chain unfolding, which causes exposure of hydrophobic patches on the protein surface resulting in intra molecular adhesion followed by the protein aggregation.

The resistance to the oxidative stress, the proliferative activity, the immunophenotype stability, and the ability to differentiate in the adipogenic direction of MSCs from adipose tissue of rats after the incubation of cells in the presence of quercetin has been investigated. The cultivation of MSCs in the presence of 100 nM – 100 mM quercetin enhances the antioxidant defense system activity and the resistance of cells to the oxidative stress, decreases the intracellular ROS content (hydrogen peroxide), and inhibits the adipogenic differentiation of cells. At concentrations of 10–100 nM, polyphenol has a stimulating effect on the proliferative activity of MSCs and does not affect the immunophenotype of cells. At concentrations of 10–100 mM, quercetin decreases the proliferative activity of the cells and changes the expression of markers of multipotent MSCs CD29, CD44, and CD90.

A full nucleotide sequence of the β-galactosidase gene (β-gal) was deciphered by cloning in plasmid pJET1.2 of DNA fragments containing β-gal of bacteria Arthrobacter sulfonivorans LF-GAL, their subsequent sequencing and comparison with the known sequences from the GenBank database. It was deposited under access number KM2778940.
The evaluation of the β-gal structure showed that it is composed of 3132 b.p. encoding 1043 amino acids making up a β-galactosidase subunit with a molecular weight of 113.6 kDa. It was found that β-gal of the examined strain is characterized by the highest degree of similarity to the genes encoding β-galactosidase in the genus Arthrobacter (66–72 %).
The amino acid composition of enzyme proteins from A. sulfonivorans LF-GAL matches that of other representatives of the genus Arthrobacter by 59–95 %. The analysis of the enzyme protein amino acid sequence by BLAST software package demonstrated that β-galactosidase of A. sulfonivorans LF-GAL comprises conservative sequences typical for glycosyl hydrolase family 2.

The changes in the ABA contents in rye plants are investigated in the development of different protective reactions against rust infection. A temporary significant increase in the ABA content both in resistant (Secale sp. derzhavinii – Puccinia dispersa), and in incompatible (Secale sereale grade Igumenskaja – Puccinia coronifera) combinations can be a signal to involve antistressful programs in infected tissues directed against pathogen suppression, whereas a high ABA concentration in all pathogenesis stages in a susceptible pathosystem reduces the efficacy of plant antistressful programs and results in the development of disease.

A preliminary intake of probiotics has a positive effect on the structural and functional status of the heart with its chronic failure. There was a decrease in the frequency of a pathological Q-wave on ECG, reducing the fibrosis degree and the conservation of the volume of cardiomyocytes; wavy deformations and cardiac myocyte vacuolization were not seen. There was a decrease in blood concentrations of CRP.

The key condition for radical progress in technology in the 21th century is the availability of a technique for the controlled production in a solid of 3D patterns incorporating regions of desired physical and chemical properties. It is especially urgent for the creation of nanometer areas. In this article, a method for changing the silicon bipolar microwave power transistor’s characteristics in a direct and deliberate manner by modifying the chemical composition at the molybdenum–silicon boundary, the electrophysical properties of molybdenum–silicon contacts, and the electrophysical characteristics of transistor structure areas by the phosphorus ions irradiation of generated оhmic molybdenum–silicon contacts to the transistor emitters is proposed for the first time. The possibilities of this method are investigated and confirmed experimentally.

Studies found that the pH of the meat of the experimental steers was at 5.8–5.9 (р < 0.05), which corresponds to the NORquality raw materials. According to the content of fat and protein, aberdeen-anguss × black pied bulls were superior to blackmotley and hereford × black and white peers by 1.9 (р < 0.05) – 1.3 percentage points and 1.8 (р < 0.05) – 0.5 percentage points, respectively. All meat samples met the requirements of SANPIN 11-63 RB98.

Studies found that the pH of the meat of the experimental steers was at 5.8–5.9 (р < 0.05), which corresponds to the NORquality raw materials. According to the content of fat and protein, aberdeen-anguss × black pied bulls were superior to blackmotley and hereford × black and white peers by 1.9 (р < 0.05) – 1.3 percentage points and 1.8 (р < 0.05) – 0.5 percentage points, respectively. All meat samples met the requirements of SANPIN 11-63 RB98.