Synthesis and antiviralactivity of 2,3-<Emphasis Type="Italic">seco</Emphasis>-derivatives of betulonic acid

A lupane 2,3-seco-aldehydoacid that was oxidized further to the 2,3-seco-diacid was synthesized by Beckmann fragmentation of the α-hydroxyoxime of betulonic acid. It was found that both 2,3-seco-derivatives were capable of suppresing reproduction of Herpes type 1 and flu A viruses (EC₅₀ from 1.9 to 21.3 μM).     

Effect of temperature on the fracture surfaces of filled systems based on SKS-85 butadiene-styrene copolymer

The tear fracture surfaces of mixtures of SKS-85 butadiene — styrene copolymer (85% styrene) with ordinary (carbon black, chalk) and polymeric (Kapron and cellophane powder) fillers have been investigated on the interval from –60 to +40°C. As the temperature varies within the limits of the glassy state (T_g SKS-85=+24°C) of the filled polymer, the nature of the fracture surface of specimens of filled mixtures, like that of the unfilled polymer, changes; in the region of the temperature transition of the copolymer associated with the mobility of the phenyl groups (–10±5°C) there is a slowing of the fracture process. At temperatures below the T_g of the copolymer the tear fracture surfaces of specimens of mixtures containing ordinary and polymeric fillers differ sharply. The introduction of fillers (20 vol. %) with a coefficient of thermal expansion different from that of the filled polymer considerably reduces the resistance of the material to fracture and leads to a sharp increase in the rate of crack propagation; the introduction of polymeric fillers with coefficients of thermal expansion similar to that of the filled polymer leads to an increase in the resistance of the material to fracture and to a decrease in the rate of crack propagation.Moscow Technological Institute of the Meat and Dairy Industry; State Institute of Polymer Adhesives, Kirovakan. Translated from Mekhanika Polimerov, No. 5, pp. 819–826, September–October, 1969.     

Effect of the physical state on tearing of amorphous polymers

The temperature dependence of the basic tear characteristics of deformation and failure of SKS-85 copolymer in the range from Tg to T>T_f is examined. It is established that the total work done in tearing the polymer in the brittle state is determined by the work of deformation up to separation of the specimen into two parts. In contrast to this, the total work done in tearing the polymer in the high-elastic state is determined mainly by the work of formation of the tear surface.Mekhanika Polimerov, Vol. 1, No. 5, pp. 71–77, 1965     

Antibodies-Abzymes with Antioxidant Activities in Two Th and 2D2 Experimental Autoimmune Encephalomyelitis Mice during the Development of EAE Pathology

The exact mechanisms of multiple sclerosis development are still unknown. However, the development of EAE (experimental autoimmune encephalomyelitis) in Th and 2D2 mice is associated with the infringement of the differentiation profiles of bone marrow hematopoietic stem cells which are bound with the production of compounds that are harmful for human autoantibodies-abzymes that hydrolyze myelin oligodendrocyte glycoprotein, myelin basic protein, and DNA. It showed that autoimmune patients’ antioxidant IgG antibodies oxidise some compounds due to their peroxidase (H₂O₂-dependent) and oxidoreductase (H₂O₂-independent) activities more effectively than those in healthy humans can. It was interesting to identify whether the redox activities of the antibodies change during the development of autoimmune diseases. Here, we analyzed the change in these redox activities of the IgGs from the blood of Th and 2D2 mice, which corresponded to different stages of the EAE development. The peroxidase activity in the oxidation of ABTS (2,2′-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid)) in the Th (4-fold) and 2D2 (2-fold) mice IgGs, on average, is higher than the oxidoreductase activity is. The peroxidase activity of the Th (1.9-fold) and 2D2 (3.5-fold) mice IgGs remarkably increased during the 40 days of the spontaneous development of EAE. Forty days after the immunization of the MOG peroxidase activity, the IgGs of the Th and 2D2 mice increased 5.6–6.0 times when they were compared with those that presented no increase (3 months of age). The mice IgGs were oxidized with 3,3′-diaminobenzidine (2.4–4.3-fold) and o-phenylenediamine (139–143-fold) less efficiently than they were with ABTS. However, the temper of the change in the IgG activity in the oxidation of these substrates during the spontaneous and MOG-induced development of EAE was close to that which occurred for ABTS. All of the data show that the IgG peroxidase and oxidoreductase activities of EAE mice can play an important role in their protection from toxic compounds and oxidative stress.     

Application of microemulsions to the recovery,preconcentration, and determination of ten surfactants from various soils

The application of a microemulsion (ME), consisting of 3% of sodium dodecyl sulfate, 0.8% of benzene, 0.6% of n-butanol, and 90.2% of water, to the extraction of ten polycyclic aromatic hydrocarbons (PAHs) from soil and simultaneous preconcentration of the analytes in the organic phase after separation of the microemulsion is demonstrated. PAHs were determined by HPLC with fluorimetric detection. The recovery rates of PAHs from different types of soil (sand, peat, and clay) are 90–105%. The preconcentration ratios of PAHs in the organic phase formed after the separation of the microemulsion were 5–6.5; the limits of detection were 0.1–0.7 μg/kg. The duration of sample preparation was 20 min.     

Some results of measurement of atmospheric temperature and density using artificial periodic inhomogeneities of the ionospheric plasma

We present the preliminary results of measurement of atmospheric temperature and density at the E-region heights near Nizhny Novgorod in the 1990–1991 period (λ=56.15°N, ϕ=44.3°E). The monthly mean temperature and density are given in the height interval 100–110 km for September and October 1990. The temporal variations of temperature and density, associated with the propagation of acoustic-gravity and internal waves, are presented. The influence of natural turbulence on the measurement accuracy has been analyzed. The method is based on the generation of artificial periodic inhomogeneities (APIs) by a powerful radio wave and registration of the amplitudes of pulse probe radio waves backscattered by APIs. Radiophysical Research Institute, Nizhny Novgorod, Russia. Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Radiofizika, Vol. 41, No. 3, pp. 348–357, March, 1998.     

A rapid method of sample preparation for determining arsenic in water by stripping voltammetry

A procedure was developed for sample preparation for the further determination of arsenic in potable and natural water and process solutions by stripping voltammetry (SV). To minimize the losses and simplify the procedure, arsenic(III) was oxidized by the ozonation or UV irradiation of the solution in the presence of sulfite, chloride, or hydroxide ions, which increased the oxidation efficiency. The time required for 100% oxidation does not exceed 60 s for an arsenic concentration of no more than 1 mg/L. The reduction to arsenic(III) was performed photochemically in the presence of sodium sulfite for 5 min. Further stripping voltammetric determination was performed in the same solution using a gold-plated carbon electrode. The developed procedure is rapid, simple, and easy-to-automate.