Vol. 47 No. 3 (232) (2013)

New derivatives of 2,5-dihydro-2-oxofurans were synthesized by the interaction of 3-acetyl-4,5,5-trimethyl-2,5-dihydro-2-oxofuran with N-nucleophiles containing aromatic and heterocyclic substituents.

New enamines of Gewald’s 4(5)-phenyl substituted thiophenes interaction with primary amines allowed to obtain 5(6)-phenylthieno[2,3-d]pyrimidin-4-ones with variable N³-substituents.

The interaction of chromium(VI) with 2-(3-(azepan-1-yl)-2-hydroxypropilthio) acetic acid has been studied by means of potentiometric, amperometric and spectrophotometric titration methods. The titration is possible to carry out in the acidity range $3.0-7.0~mol / L$ by sulfuric acid. Molar ratio of the reacting agents is [Cr(VI)] : [Reagent] $= 2 : 3$. Conformity to the Beer’s law is preserved when $8.3\cdot10^6-2.0\cdot10^3~mol / L$ at $E=+0.2~V$ and when $2.0\cdot10^5-2.0\cdot10^3~mol / L$ at $E =+1.2~V$ chromium(VI) solutions were titrated. The technique elaborated has been approved during the analysis of standard chromium-containing ore with standard relative deviation 0.61% . Possible scheme describing the interaction of chromium(VI) with the reagent has been suggested. 

Interreaction of ThF₄ and CsF in solution in the range of 700–900°C has been studied by thermographic means. It has been stated that in the system following chemical compounds are formed (that melt congruent without decay):   Cs₃ThF₇ ($T_m$ =765°C), CsThF₅ (825°C), Cs₃Th₂F₁₁ (842°C), CsTh₆F₂₅ (844°C).

Textural characteristics of silica obtained from the gels have been introduced, which were formed in a pulsing magnetic field. It is shown, that all the characteristics of the resulting silica porosity, especially the pore distribution according to the size, essentially depend on the frequency of the magnetic field. It has been suggested that in dilute gels of the polysilitic acids pseudo-mesophase aggregate systems may be formed, which similar to liquid crystaline structures are capable of restructuring under the influence of weak electromagnetic fields. 

After inactivation by ethylenediaminetetraacetic acid (EDTA) the subunits (dimer, monomer) of Rana ridibunda frog’s liver arginase differs by sensitivity towards thiol reagents. Moreover, the particular activation of subunits is also observed at the presence of p-chloromercuribenzoate (p-CMB). It is notable, that p-CMB significantly decreases the activity of reactivated enzyme in the presence of Mn²⁺ ions, despite the fact that in native extracts the enzyme is not inhibited by the thiol reagent. Here we discussed the effect of p-CMB in the inactivation process not only as a result of SH groups’ modification, but also because of structural changes in native conformation by EDTA and non specific reaction of p-CMB with other functional groups.

It was found that the levels of Adenosine deaminase activity in joint effusions of patients with rheumatoid arthritis and osteoarthritis differ significantly (p < 0.0001). To differentiate the arthritis of these two etiologies, the cutoff value of the enzyme activity in synovial fluid was evaluated as 12 IU/L with sensitivity 0.96, specificity 0.89 and diagnosis efficiency 0.93. Based on this observation, we can offer using in clinics of Armenia the Adenosine deaminase activity in synovial fluid for quick diagnosis of rheumatoid arthritis as a sensitive, specific, low-cost and technically convenient test.

In this paper a method is presented for determining the permeability coefficient of bilayer lipid membrane (BLM) for porphyrins by UV/Vis spectrophotometry. BLM is formed on the hole separating two compartments of the cell. The coefficient permeability of BLM is calculated for meso-tetra-[4-N-(2'-hydroxyethyl)pyridyl] porphyrin. The proposed method can be used to determine the permeability coefficient of BLM for other substances. 

The modulation effect of 8 Hz (2.5 mT) extra low frequency electromagnetic fields (ELF EMF) on cisPt induced changes of cell hydration and number of ouabain receptors (Na⁺/K⁺ ATPase molecules) in membrane of Sarcoma-180 tissue was studied. Tissue hydration was measured as wet mass/dry mass and expressed as a water content of g/g in dry mass. The number of ³H-ouabain receptors in membrane was counted by isotope scintillation counter. It was shown, that 8 Hz ELF EMF has dehydration effect on cancer tissue. Besides, 8 Hz ELF EMF is not a modulator of cisPt effect on tumor tissue.

Analyses of some physicochemical properties of soil samples from six of the most risky sites in mining territories around Kajaran Town and from unpolluted site as a control revealed that the studied soils were basically weakly eroded, and they were classified from moderately bad to good according to texture. In some soil samples much stoniness was observed. The root systems were comparatively well-developed almost in all soil samples and they were rated from medium to good. Experiments have led us to the assumption that the erosion processes in studied sites were conditioned by natural climatic conditions, high slope gradients and high anthropogenic impact.

On the basis of the sodium salts and urea derivatives of isocyanuric acid and transition metals new chelate complexes were synthesized. It is shown that the chelate complexes based on disodiom salt 1-monokarbamidilmethyl isocyanurate with Ni²⁺ and Co²⁺ ions have structure of spatially cross-linked clusters, while chelate complexes based on monosodiom salt 1,3-karbamidilmethyl isocianurate have ladder structure. The synthesized chelate complexes are studied by IR spectroscopy and elemental analysis.