Vol. 56 No. 3 (259) (2022)

In this work, the conformational and vibrational analysis of dipropyl sulfone in its isolated gaseous state with identification of all stable conformers, their energy and degeneracy, relative population determined by Boltzmann distribution, as well as IR spectra have been performed by density functional theory (DFT) methods. Several DFT methods and basis sets were tested. It was demonstrated that the various local and hybrid DFT functionals such as well-known B3LYP, regardless of the size of basis sets, completely fail in the prediction of correct molecular structures, let alone the IR spectra. It was found that only long-range corrected hybrid density functionals, combined with decently sized basis sets are capable to predict correct values of dihedral angles between non-bonded atomic groups: the most important coordinates in conformational analysis. Thus, wB97XD/6-311++G(2df,2pd) method/basis set combination appears to be the best method for the titled system both in terms of geometry and IR spectra prediction. A detailed analysis of the potential energy surface revealed the existence of 28 distinct conformers with various populations at 298 K, which have significant impact in the simulated IR spectra. The linear scaling equation (LSE) fitting methodology was successfully adopted for the calibration of wavenumbers and achievement of the best match between theoretical and experimental absorption regions of functional groups in sulfones. Moreover, in the construction of the simulated IR spectra, the Lorentzian broadening of each calculated mode with different full widths at half maximum was considered to obtain extinction coefficients, thus more realistic ε(ν) dependency, that is directly comparable with experimental spectra. The authenticity of the results obtained have been verified by comparison with existing experimental literature data on sulfones.

The work is devoted to a comparative study of the fatty acid composition of white and black sesame oils, as well as the development of a relatively effective method for isolating the natural antioxidant sesamol. The purpose of this work was to determine the comparative indicators of the content of fatty and free organic acids in the studied oils by gas and high-performance liquid chromatography, confirm their suitability and further use. The optimal conditions for obtaining high-quality unrefined oil from sesame seeds for the food and pharmaceutical industries were determined by the method of cold pressing (pressing chamber temperature was 100℃, oil outlet temperature was ≤ 40℃). Under these conditions, the oil yield was 30% and 27%, respectively. It was shown that finished sesame seed oils contain a highly effective natural antioxidant sesamol (oxyhydroquinone methyl ester) – 0.140 mg/kg, due to which they can be stored at room conditions for more than 3 years. The extracts of squeezes of sesame oils contain valuable free organic acids: oxalic – 0.017 mg/mL, malic – 0.02 mg/mL, fumaric – 0.001 mg/mL. Based on the research, the fatty acid composition of oils was determined and a relatively effective method for the complex processing of sesame raw materials was developed to obtain a highly effective natural antioxidant sesamol.

In the present work the effect of resonant electromagnetic irradiation (EMI) and acetylsalicylic acid (ASA) on value change of the surface tension coefficient of human blood plasma has been studied. It was shown that both the plasma irradiation and the ASA insertion into plasma result in changing of the surface tension coefficient of human blood plasma, as well as affect the surface buffering. These changes are due to the fact that the mentioned factors invoke conformational alterations in the structures of plasma proteins, though we assume that ASA contributes in stabilization of structural changes of proteins.

The effect of various doses of γ-irradiation on the biochemical composition of the nuclear fractions of wheat seedlings has been investigated. The research results indicate a direct dependence of changes in the biochemical composition of nuclear membranes and soluble nuclear fraction on the magnitude of the radiation dose. A change in the protein content in the fraction of the nuclear membrane and in the soluble nuclear fraction of the cell nuclei of the seedlings of irradiated seeds was observed. The data obtained indicate that ionizing radiation as a result of chain reactions changes the content of nuclear fractions, which in turn leads to a change and disruption of the functional ability of the nucleus.

The study of the interaction of phenothiazine dye methylene blue (MB) and phenantridine dye ethidium bromide (EtBr) with synthetic single-stranded (ss)-poly(rA) has been carried out at the ionic strength of the solution 0.1 mol, in wide interval of ligand/phosphate ratio change, by the method of absorption spectroscopy. The binding curves of MB and EtBr with ss-poly(rA) were obtained. MB was shown to interact with this polynucleotide cooperatively, while for EtBr the cooperativity was not revealed. The binding parameters of MB and EtBr with ss-poly(rA) were determined – association constant K and base number n per binding site. It was shown that both ligands bind to ss-poly(rA) at least by two modes, though the affinity of MB to the polynucleotide is higher by an order, than that of EtBr.

The processes of lipid peroxidation (LPO) were studied in rat brain and liver tissues under normal conditions, as well as under conditions of hypobaric hypoxia, since it is known that hypoxia causes the development of LPO in the cells of organism tissues. It has been also studied the influense of dry flowers of Trifolium pratense L. (red clover) and Crataegus laevigata (midland hawthorn) on lipid peroxidation, which triggers by hypobaric hypoxia. It has been shown, that the end product of lipid peroxidation malondialdehyde in rat brain and liver tissues was significantly decreased with the addition of plants flowers to the diet of animals, especially in the case of C. laevigata.

Modeling of methemoglobinemia (MetHb) led to a violation of antioxidant protection, which was manifested by a decrease in the activity of enzymes of the primary link of the antioxidant system – superoxide dismutase and catalase in blood plasma and brain homogenates of experimental animals. The state of MetHb also led to an increase in the concentration of malondialdehyde, an indicator of lipid peroxidation, as well as an indicator of oxidative modification of proteins. It has been established that the antihypoxic activity in the application of succinic acid significantly suppresses the biochemical changes caused by the hypoxic state.

In the current research, we investigated soil micromycetes-decomposers around Kajaran City. As a result of the studies, 30 micromycetes were identified as belonging to 16 genera of which 1 belongs to Basidiomycota, 1 – to Mortierellomycota, 3 – to Mucoromycota, and 11 – to Ascomycota. Changes in the species composition and some morphological features of soil fungi are observed depending on the industrial pollution.

Holoparasitic plants of the family Orobanchaceae are represented by 36 species belonging to 4 genera in Armenia. Despite the fact that the secondary metabolites and their pharmacological properties are not well studied, the limited data on this topic is already a promising source for different bioactive compounds. In this paper, we are representing the antioxidant properties and phenolic content of four species belonging to Orobanchaceae family. The highest antioxidant activities were recorded for Orobanche kurdica alcoholic extract. Water soluble phenols may explain the great antioxidant capacity of the aqueous extract of Diphelypaea tournefortii.

Hypobaric hypoxia causes degenerative changes in different parts of the brain, which leads to the formation of cerebral edema. This study aimed to investigate the morphohistological changes in the brain of rats exposed to hypobaric hypoxia. In particular, the hippocampus, cerebral cortex, and striatum were studied. Animals were exposed to hypobaric hypoxia for 10 days. Histomorphological examination showed degenerative changes in the hippocampus, dentate gyrus, and striatum, accompanied by pyknosis of neuronal nuclei, cytoplasmic vacuolization, and neuronal shrinkage, while the cortex of the large hemispheres remained almost intact. Histological studies showed that different parts of the brain respond to hypoxic conditions with different manifestations.

The change in the functional state of the body of first-year students under the influence of physical activity was studied. As the analysis of the obtained data showed, running at a distance of 500 m, both for girls and boys, leads to unidirectional shifts in all the studied indicators of varying severity. The functional systems of the organism of first-year students of the university react to physical activity by the tension of the sympathetic circuit of the regulation of adaptive mechanisms.