Optical properties and orientational order of deoxyribonucleic acid molecules at interfaces

A high degree of planar orientational order of DNA molecules in thin films has been discovered by the oblique-polarized-beam method. The coefficients of surface birefringence of films with different thicknesses are measured. The thickness of optically anisotropic surface layers, which are characterized by macroscopic values higher than the diameter of DNA molecules by three orders of magnitude in terms of thickness, is determined. A difference in the main polarizabilities of the monomer unit of DNA, which is estimated for the films, is compared with the corresponding value for the solution measured by flow birefringence. The effect of temperature on the coefficient of birefringence of the films is examined. A comparison of the data on the native and denatured DNA shows that the degree of orientational order for the single-helix structure is smaller than that for the double helix.     

Macroscopic evidence of soliton formation in multiterawatt laser-plasma interaction

A novel physical phenomenon has been observed following the interaction of an intense (10(19) W/cm(2)) laser pulse with an underdense plasma. Long-lived, macroscopic bubblelike structures have been detected through the deflection that the associated electric charge separation causes in a proton probe beam. These structures are interpreted as the remnants of a cloud of relativistic solitons generated in the plasma by the ultraintense laser pulse. This interpretation is supported by an analytical study of the soliton cloud evolution, by particle-in-cell simulations, and by a reconstruction of the proton-beam deflection.     

Effects of substituents in reactions of sulfenyl chlorides with derivatives of phosphonallenic acids

Conclusions In the reaction of sulfenyl chlorides with derivatives of allenylphosphonic acid, the structure of the products formed is determined by the effect of substituents at the P atom and the terminal C atom of the cumulene, and also by the nature of the organyl group attached to the S atom in sulfenyl chloride.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 8, pp. 1851–1859, August, 1933.     

Narrow-band terahertz wave generation and detection in one periodically poled lithium niobate crystal

In this article, we present studies on therahertz (THz) wave generation and frequency up-conversion in a periodically poled lithium niobate (PPLN) crystal. A frequency at 1.37 THz was generated as femtosecond pump pulses passed through a PPLN crystal with grating periods of 30 μm. The pump-induced THz wave interacts with the probe wave in the crystal by frequency mixing. The frequency up-converted THz wave is easily detected by a normal photodiode. A new scheme for generation and detection of THz wave in one non-linear crystal was proposed.     

Cyclization of N-alkylazinium cations with bifunctional nucleophiles. 24. Synthesis of condensed 1,2,4-triazino- and 1,2,4-oxadiazino[5,6-b]quinoxaline systems

Cyclization of quinoxalinium salts with amidoximes and amidhydrazones yields partially hydrogenated derivatives of new 1,2,4-oxadiazino- and 1,2,4-triazino[5,6-b]quinoxaline heterocyclic systems.For Communication 23, see [1].Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 8, pp. 1118–1121, August, 1987.     

Study of sorption and catalytic activity of peat-based composition material in relation to organic pollutants in waters

The effect exerted by modifying iron(III) chloride additive on the sorption and catalytic activity of granulated iron-containing peat composition in removal of oxalic acid was studied depending on the conditions of the solution treatment (ozone, UV radiation, and hydrogen peroxide). The conditions for virtually complete absorption of oxalic acid from model solutions were chosen.     

Reactions of aromatic acetylenic ethers with triethylgermane

Conclusions The addition of Et₃GeH to the phenoxy- and phenylthioacetylenes under the influence of (Ph₃P)₃RhCl is both nonstereo- and nonregiospecific. The analogous reaction with 3-aroxy-1-propynes is stereospecific but nonregioselective.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 11, pp. 2618–2620, November, 1982.     

Determination of the sorption characteristics of glauconite during extraction of a pharmaceutical from an aqueous medium

A technique for preparing enriched glauconite on the basis of a natural mineral from the Beloozyorskoe field of Saratov oblast has been developed. The results of a study of the chemical composition, surface structure, and certain physicochemical properties of the samples of the sorbent are presented. The sorption of ambroxol hydrochloride ions from aqueous solutions has been studied using natural and enriched glauconite. The sorption isotherms, are approximated by the Langmuir equation, have been obtained, and the values of the maximum sorptive capacities have been calculated. Based on the obtained data, conclusions have been drawn on using the studied natural mineral sorbents to extract the above-mentioned substance from aqueous solutions.