Vol. 49 No. 2 (237) (2015)

Effect of aqueous soluble vitamins nicotinic acid, pyridoxine and biologically active ions Co²⁺, Mn²⁺, Cu²⁺ on critical micelle concentration (cmc) of anionic surfactant sodium pentadecylsulfonate, cationic surfactant cetylpyridinium bromide and nonionic surfactant hexadecylpoly[oxyethylene(20)] alcohol (C₁₆A₂₀) in aqueous solutions at 303.15 K was studied. It was shown that with increase of vitamins concentration the cmc of studied anionic sodium pentadecylsulfonate increases and cmc of C₁₆A₂₀ decreases. In the presence of metal-ions cmc of the studied surfactants decreases.

3-Cyanopyridine-2(1H)-ones containing unsaturated substituents at the position C-4 and various substituents at N-1 of the ring have been synthesized as new potential bioactive compounds by interaction of ethyl ylidene cyanoacetate with dimethylformamide dimethyl acetal, and simultaneous reamination-cyclization of obtained derivatives with amines to targeted 3-cyanopyridine-2(1H)-ones.

New derivatives of 5-oxotetrahydrofuran were syntesized by efficient and convenient reactions from 2-(2,2-dimethyl-5-oxotetrahydrofuran-3-yl)acetyl chloride.

A method of sodium tripolyphosphate peroxo solvate synthesis has been developed. It has been shown that the hydrogen peroxide content in peroxo solvate is 28 wt.% and the solid product exists in crystalline form.

It has been investigated the influence of pH on iron migration in water–bottom sediment system in the Hrazdan River based on 2012–2013 hydrological investigations. Obtained results show that in some sampling points the iron concentration exceeded the maximum permissible concentration. It has been observed particularly in August 2012. Correlation coefficients are given based on data analysis results. 66 samples of water and bottom sediment have been taken from six sampling points.

On the example of the model reaction of cumene oxidation herbal extracts are classified as antioxidants. It is established that according to the character of oxidation influence on the process, the extracts are divided into four major groups: 1) extracts, which function as conventional classic antioxidants, in the presence of these extracts on the kinetic curves of oxygen absorption, distinct induction periods appear; 2) extracts-moderators, in the presence of which kinetic curves of oxygen absorptions function without induction periods; 3) extracts, which operate as antioxidants at low concentrations and at relatively high concentrations, they undergo auto oxidation; 4) extracts, that inhibit the oxidation process to some extent. The mechanism of the effect of the extracts as antioxidants on the oxidation of cumene covering these groups is suggested.

This research indicated various fungal infections in different parts of several medicinal plants that grown in arid woodlands of Vayots Dzor region of Armenia. In this territory we investigate 289 species of medicinal plants belonging to 175 genera and 58 families. 39 species of microscopic fungi were found from 41 species of medicinal plants from this area. Among the taxa of fungi 18 species belong to Ascomycota, 7 belong to Basidiomycota and 1 belongs to Oomycota divisions. Golovinomyces genus from powdery fungi was the dominant for 11 higher plants, the most common species of micromycetes in this territory is G. galeopsis (about 15.4% of the total), which causes of medicinal plants from the family Lamiaceae.

In the current work the investigation of interaction between polyguanylic acid and ethidium bromide (EtBr) at different ionic strengths and at three different temperatures has been carried out. Based on absorption spectra of formed complexes, adsorption isotherms were constructed and binding constants were determined. Thermodynamic parameters of this interaction were determined as well. Obtained data show that in four-stranded structure, the “classical” intercalation becomes impossible and the only possible binding mode remains semiintercalation. It was also shown that thermodynamic parameters of interaction by semi-intercalation mode do not strongly depend on the ionic strength of solution.

In the present work the description of absorption spectra of ethidium bromide complexes with synthesized polyribonucleotide by several modes has been carried out. The binding constant value and the values of changes of thermodynamic parameters were determined. It was shown that at the description by linear binding isotherm the value of enthalpy and the number of nucleotides corresponding to one ligand molecule at interaction saturation are approximately the same as real ones, but the values of the binding constant, Gibbs free energy change and entropy change differ from real values.

In the paper morphological characteristics of blood parasites of 8 species of rock lizards of Darevskia genus were investigated. Their prevalence in the host organism was revealed.

The present study was aimed in assessing the heavy metal pollution of the soils around Kajaran Town, Armenia and related environmental risks. The investigations showed that the soils around the mining complex near Kajaran Town were highly polluted with heavy metals (Mo, Cu, Pb, As, Zn, Ni) and this was conditioned by Zangezur copper and molybdenum combine activity. Such heavy metal pollution degree in the soils may pose risks to agricultural production and the health of population especially children in this territory.