Vol. 52 No. 1 (245) (2018)

This paper studies volumetric properties of L-ascorbic acid+ethanol–water ternary systems. The densities of solution of L-ascorbic acid (vitamin C) in ethanol–water mixtures with various compositions have been measured over the available concentration range at temperatures from 298.15–318.15 K. Apparent molar volumes, standard partial molar volumes and transfer partial molar volumes of L-ascorbic acid were determined in ethanol–water mixtures. The competitive intermolecular interactions between molecules of ascorbic acid and components of ethanol–water mixtures are responsible for the irregular volumetric behavior of these systems.

LiCl–dimethyl sulfone and LiCl–diethyl sulfone systems have been investigated by restricted Hartree-Fock (RHF/6-311++G(d, p)) computations in order to establish the structural and spectral parameters of solute–solvent systems. The calculations show the existence of two stable LiCl–sulfone (1:1) structures and one transition state. It was shown that sensitivity of the CH and SO stretching vibrations to the interaction between LiCl and sulfone strongly depends on the structure of the complex, and the difference in their properties is explained in the frame of vibrational Stark effect, rather than by specific solute-solvent interactions only. Results are compared to the solid state experimental spectra.

Interaction between bovine serum albumin (BSA) and (R)-5-(3-(4-(azepan-1-ylmethyl)-1H-1,2,3-triazol-1-yl)prop-1-en-2-yl)-2-methylcyclohex-2-enone (Triazole-A) was studied at 298 K and 308 K using fluorescence spectroscopy method. It was shown that the quenching mechanism of BSA by Triazole-A was initiated by a dynamic collision. Synchronous fluorescence measurements indicate that binding between Triazole-A and the protein does not lead to a change in the polarity of the microenvironment of the tryptophan and tyrosine residues.

The influence of vitamins Bc (folic acid, FA), B₁ (thiamine, TA) and C (ascorbic acid, AA) on H₂O₂ (HP) decomposition rate in aqueous solutions was studied using gasometric method. In alkaline medium in the presence of FA the reactions are carried out at [H₂O₂]₀=[HOO^–]=0.5 M. [FA]0 is changed in the range 0–2.8∙10^–3 M. It is established that the reaction rate (W) decreases more than twofold. It is assumed that FA effectively reacts with HO^• and HOO^•, which are chain carriers. So the reaction runs by radical-chain mechanism. In acidic medium (pH 3.5) catalyzed by Fe(II) cations HP decomposition occurs mainly by radicalchain mechanism. TA (0–2.5∙10^–4 M) also decreases W more than 4 times. At pH 3.5, [TA∙HCl]₀ ≥ 1∙10^–4 M there is no O₂ evolution. The AA influence on the HP decomposition, W is studied at pH 3.5. In the presence of AA, [AA]₀≈1.25∙10^–3 M, W also decreases the radical-chain run catalyzed by Fe(II) cations HP decomposition.

New methods for synthesizing polyols have been developed: erythritol, 1,2,3-butanetriol and 1,2,4-butanetriol from 1,4-dichloro-2-butene, 1-chloro-2-butene and 4-chloro-1-butene respectively. The esterification of the resulting erythritol, 1,2,3-butanetriol and 1,2,4-butanetriol with palmitic, stearic, lauric and oleic acids gave the corresponding esters. The physicochemical constants of the obtained compounds are determined. New non-glyceride oil-like products can be used to screen dietary oils and fats.

Biologically active compounds in aqueous and ethanol extracts from branches and leaves of Armenian Pistacia atlantica were determined. The presence of flavonoids, floroglucides, coumarins, tannins, anthracene derivatives, sugars, saponins, phenolic glycosides and alkaloids are shown. Flavonoids in ethanol extracts from leaves and branches were obtained more (1.81 and 0.95 mg/g) than in aqueous extracts (0.95 and 0.3 mg/g). The most amounts of coumarins (2.2 mg/g) and anthracene derivatives (8.5 mg/g) were determined in ethanol extract from leaves. The aqueous extract from leaves was more effective in inhibiting of dipeptidyl peptidase IV and adenosine deaminase activities.

More than 600 strain isolates were obtained from 200 matsun and salted cheeses samples. The strains were screened for potential probiotic properties, antibiotic and phenol resistance. Eight different lactic acid bacteria strains with high antibacterial activities were identified by multiphase approach comprising classical and molecular methods and indicated their relation to four species distributed in two genera Lactobacillus (L. rhamnosus, L. helveticus, L. delbrueckii) and Enterococcus (E. faecium).

The study of joint binding of intercalating compounds – ethidium bromide (EtBr) and mitoxantrone (MTX) with double-stranded DNA (ds-DNA) and poly(rA)-poly(rU) (ds-RNA) has been carried out by UV-melting method. The melting parameters of the complexes of both EtBr–ds-DNA–MTX and EtBr–ds-RNA–MTX triple systems were obtained. Changes of the melting parameters of these complexes revealed that EtBr binds to both ds-DNA and ds-RNA by several modes, though these binding modes of EtBr with nucleic acids (NA) were performed in the presence of MTX as well. MTX binds to ds-DNA and ds-RNA by semi-intercalation mode although this ligand shows more pronounced affinity to DNA than to RNA. It was found that at the joint binding of both ligands to NA a competition emerges between them and the effect of EtBr on the melting parameters of NA prevails.

In this article we have considered patients’ physiological, psychological and social peculiarities with cervical osteochondrosis, as well as the ways of its prevention and treatment. It has been detected that patients with cervical osteochondrosis have reduction of activeness of defense mechanisms, which manifests in arterial pressure as well as anxiety, aggression and low level of activity. At the same time these patients are described by high level of tiredness. The complex program, based on the obtained data (includes physical, physiotherapeutic and psychological affective technologies), promotes neurovegetative system optimization, and as a result affects the improvement of patients life quality.

To construct the binding isotherms of nucleic acid–ligand it is necessary to determine physical characteristics of completely bound state of ligand (A_b) experimentally. It is often impossible to determine A_b experimentally, due to which as A_b the value of the parameter is accepted, which almost does not change in the experiment error framework. Calculations show that in this case the binding constant determination error does not exceed 10%.