Vol. 50 No. 2 (240) (2016)

Transport properties of reverse micellar system of n-heptane–sodium bis (2-ethylhexyl) sulfosuccinate (AOT)–water + diethyl sulfoxide (DESO) have been studied by densitometry and viscosimetry. The relative viscosities (ηr) of the systems were calculated at concentration range of AOT from 0.106 to 1.912 mol/kg, constant degree of AOT hydration (W=[polar phase]/[AOT]=10) and at temperature range 298.15–313.15 K. Based on the plots of ηr against volume fractions of dispersed particles, the probable interactions between micelles were discussed. The obtained results were compared with those of n-heptane–AOT–water + dimethyl sulfoxide (DMSO). The presence of DESO tends to the formation of micellar aggregates at smaller concentrations of surfactant comparing with DMSO.

The reactions of 5-merkapto-3,4-disubstituted-1,2,4-triazoles with ethyl chloroacetate have been investigated. It has been shown that mercapto group reacted and S-substituted derivatives were formed. On the next step hydrazinolysis by 85% hydrazine hydrate was carried out and on the base of obtained hydrazides thiosemicarbazides were synthesized. Further by means of intermolecular cyclization bis-1,2,4-triazoles were obtained, structure of heterocyclic rings were connected by thio-methyl bridge.

The reaction of sorbitol and mannitol esterification with higher fatty acids has been investigated and the corresponding esters were obtained without using catalysts and solvents. The physical and chemical constants of esters were established. An optimal procedure of the reaction was developed.

The influence of 2-cyano-3,4,4-trimethyl-2-butene-4-olyd (unsaturated cyanolactone, UCL) and DMSO on the rate of initiated with AIBN of cumene (CU) autoxidation in chlorobenzene solution by gasometric method is studied. It is established that in the presence of UCL (for reaction order n=0.6) the stationary reaction rate R_st can be described by empirical rate law. In the case of DMSO (n=0.5) a classical rate law of radical-chain reactions in the stationary regime is occurring. In both cases the reaction begins after some induction period, τ. With increasing of [UCL]₀ τ is decreasing up to 0, when [UCL]₀$\geq 2\cdot$10^-3 M. It is shown also that DMSO decreases R_st, which, probably, can be explained by DMSO and CU competition to react with ROO^• free radicals, which are being formed in the reaction propagation step.

The sorption of Cu(II) from aqueous solutions by peat containing sorbent was studied in a dynamic mode. Peat sample was taken from Lake Sevan (near Vardenis in Gegharkunik region of Armenia). The data obtained from sorption experiments were analyzed using Langmuir and Freundlich models. Langmuir equation describes sorption isotherm of Cu(II) with high correlation coefficients, better than Freundlich model. According to Langmuir model, the maximum uptake capacity of peat containing adsorbent for Cu(II) was obtained as about 15 mg/g. The sorption properties of peat were estimated by ICP-MS.

The subject of the study is the involvement of reticular neurons (RN) of the bulbar respiratory center in respiration under conditions of hypobaric hypoxia. Such conditions were created in a laboratory altitude chamber and corresponded to a “lift” up to 8000 m altitude. At the beginning of such a “lift”, at pressure corresponding to an altitude of 4000–5000 m, a decrease in the PO2in the inspired air to 98–85 mm Hg resulted an increasing impulse activity of neurons. Within a phase of extreme hypoxia, at an “altitude” of 7500 to 8000 m ($P_{\mathrm{O}_2}$= 64–58 mm Hg), considerable suppression of the activity of bulbar RN is observed. Impulse activity of RN in different discharge frequency at different stages of hypoxia has demonstrated considerable specificity.

A widely expressed multifunctional, membrane-anchored cell surface or in a soluble form in the plasma and other body fluids serine protease, dipeptidyl peptidase IV (DPPIV), cleaves dipeptide from peptides containing proline or alanine in the N-terminal penultimate position. Several important regulatory peptides have been identified as DPPIV substrates, including neuropeptides, chemokines, and the incretin hormones, which share this conserved sequence at their N-termini. Natural substrates of DPPIV are involved in immunomodulation, psycho/neuronal modulation and physiological processes in general and the cleavage by DPPIV of these peptides resulted in their inactivation or degradation. Therefore, targeting of DPPIV and especially its proteolytic activity has much therapeutic potential. Some known and new natural substrates were discussed in this review.

Viper venom as a hemolytic biochemical “cocktail” of toxins, primarily cause to the systemic alteration of blood cells. In the sixties and seventies, human erythrocytes were extensively studied, but the mechanical and chemical stresses commonly exerted on red blood cells continue to attract interest of scientists for the study of membrane structure and function. Here we monitor the effect of Vipera latifi venom on human erythrocytes ghost membranes using phase contrast microscopy and changes in ATPase activity under snake venom influence in vitro. The ion pumps (Na⁺, K⁺)-ATPase and (Ca²⁺, Mg²⁺)-ATPase plays a pivotal role in the active transport of certain cations and maintenance of intracellular electrolyte homeostasis. We also describe the action of Vipera latifi venom on the freeradical processes in the membrane of erythrocyte ghosts and changes of activity of superoxide dismutase in course of envenomation.

The value of binding enthalpy change (ΔH) due to DNA–ligand complexformation has been determined by Van’t–Hoff mode having dependence of binding constant (K) on the reverse value of absolute temperature. Calculations that were carried out for DNA–ethidium bromide and DNA–mitoxantrone complexes showed, that if ΔH is determined from the values of K at two different temperatures, the calculated value of ΔH in the error frame coincides with its experimental value.

Water quality of the Rivers Voghji, Artsvanik and Geghi was evaluated by Armenian Water Quality Index (AWQI) for the first time. It was shown that from the source to the mouth of the river was observed the increase of the value of AWQI that indicates a decline in the water quality of the rivers from the 1st to the 2nd class of pollution. Correlation between the AWQI and other water quality indexes was established.

The 4th International Conference of CIS countries “Sol–Gel Synthesis and Investigation of Inorganic Compounds, Functional Hybrid Materials and Disperse Systems” (“Sol–Gel-2016”) by an initiative of the Institute of Silicate Chemistry of Russian Academy of Sciences (and the decision of the Organizing Committee of the previous Conference) will be held on September 19–23, 2016, in Yerevan.