Study of the physicochemical properties of aminostyrene copolymers modified by plasma treatment

The change in the surface and mechanical properties of styrene-butyl methacrylate-aminostyrene terpolymer films by plasma treatment was investigated. It was found that treatment in a direct-current discharge enhanced the mechanical strength of the terpolymer surface, which can be associated with the crosslinking of linear macromolecules into a three-dimensional network structure. It was shown that the most substantial changes in the mechanical strength are achieved in the case of terpolymer film treatment at the anode.     

Regiospecific cleavage of 1,3-dioxanes by organoaluminum compounds

Organoaluminum compounds react with 4-methyl-2-phenyl-1,3-dioxane with cleavage of the O₁-C₂ bond to give monoethers with a primary alcohol group.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 8, pp. 1036–1037, August, 1985.     

Virtual Screening in Search for a Chemical Probe for Angiotensin-Converting Enzyme 2 (ACE2)

We elaborate new models for ACE and ACE2 receptors with an excellent prediction power compared to previous models. We propose promising workflows for working with huge compound collections, thereby enabling us to discover optimized protocols for virtual screening management. The efficacy of elaborated roadmaps is demonstrated through the cost-effective molecular docking of 1.4 billion compounds. Savings of up to 10-fold in CPU time are demonstrated. These developments allowed us to evaluate ACE2/ACE selectivity in silico, which is a crucial checkpoint for developing chemical probes for ACE2.     

Specific features of infrared absorption in films materials subjected to a magnetic field

The reflection spectra and magnetorefractive effect (MRE) of metal (Co, CoFe), semiconductor (Si, GaAs), and granular and amorphous Co₃₀Ag₇₀ and Co₅₉Fe₅Ni₁₀Si₁₁B₁₅ films are studied in the IR spectral region at λ=2.5–25 μm. It is found that the IR optical properties of the ferromagnetic metal films can be described with regard to light absorption due to electron transitions in the two spin systems. The MRE is found to occur in both the ferromagnetic (Co, CoFe) and semiconductor (Si, GaAs) films. The amplitude and shape of the MRE are determined for the p and s polarizations of light. It is shown that, to a first approximation, the IR optical properties of the films with giant magnetoresistance can be described by the Drude theory, while the MRE is explained on the basis of a modified Hagen-Rubens relation. Variations in the IR reflection of semiconductor or amorphous metal films in the magnetic field are found to depend on the degree of polarization of localized electron states at the Fermi level.     

Magnetorefractive effect in (Co<Subscript>50</Subscript>Fe<Subscript>50</Subscript>)<Subscript>x</Subscript>(Al<Subscript>2</Subscript>O<Subscript>3</Subscript>)<Subscript>1−<Emphasis Type="Italic">x</Emphasis></Subscript> granular films

The reflectivity spectra and the magnetorefractive effect (MRE) of (Co₅₀Fe₅₀)_x(Al₂O₃)_1?x metal-dielectric granular films (0.07<x<0.52) are analyzed in the IR spectral range λ=2.5–25 µm. It is revealed that the specific features observed in the spectra at λ≈8.5 and 20 µm are associated with the excitation of phonon modes in the dielectric matrix. The magnetorefractive effect in the films is observed below the percolation thresh-old only in p-polarized light and above the percolation threshold for both the p and s polarizations. It is demonstrated that the optical properties of (Co₅₀Fe₅₀)_x(Al₂O₃)_1?x films in the IR spectral range, to a first approximation, can be interpreted in the framework of the effective-medium theory and the magnetorefractive effect can be explained in terms of the modified Hagen-Rubens relation.     

A study on the water permeability of poly(ethylene terephthalate) track membranes modified by dc discharge polymerization of <Emphasis Type="Italic">N,N</Emphasis>-dimethylaniline

The properties of poly(ethylene terephthalate) track membranes modified by dimethylaniline polymerization in a dc discharge were studied. The influence of plasma treatment conditions on the basic membrane characteristics: the pore size, wettability, surface charge, and water permeability, were examined. It was shown that the polymer membranes obtained were capable of reversibly responding to pH and pressure changes.Translated from Khimiya Vysokikh Energii, Vol. 39, No. 2, 2005, pp. 143–152.Original Russian Text Copyright © 2005 by Kravets, Gilman, Drachev.This revised version was published online in April 2005 with a corrected cover date.     

Specific features of the magneto-optical properties of α-Al<Subscript>2</Subscript>O<Subscript>3</Subscript> in the IR region

The spectra of reflection and magnetoreflection of light from the crystalline insulator α-Al₂O₃ in the IR spectral region (λ = 2.5–25 μm) are investigated. Some features in the magnetoreflection spectra in the wavelength range corresponding to the excitation of optical phonon modes in α-Al₂O₃ are found. A significant increase in magnetoreflection is observed near these wavelengths. The amplitude and shape of the magnetore-flection spectra for the p and s polarizations of probe light are determined. It is shown that the optical and magneto-optical properties of α-Al₂O₃ in the IR region can be described on the basis of the theory of polaron excitation. A satisfactory correlation between the theoretical and experimental spectra is obtained, which indicates that polarons play an important role in determining the optical characteristics of nonmagnetic insulators and make the dominant contribution to the magnetoreflection spectra.     

Separation flows on a concave conical wing

The results are given of an investigation into the structure of the flow and the pressure distribution on delta wings with conical concavity.     

Steroids of the spirostan and furostan series from plants of the genus Allium. XXVI. Structure of anzurogenin and anzuroside from the collective fruits of Allium suvorovii and Allium stipitatum

A new steroid glycoside of the spirostan series, anzuroside, has been isolated from the collective fruits of the cocultivatedAllium suvorovii Rgl. andA. stipitatum Rgl. (family Liliaceae, local name anzur). Enzymatic cleavage of the glycoside has given the previously undescribed steroid sapogenin anzurogenic C, which has the structure of (24S, 25S)-2,3,5,24-tetrahydroxy-5-spirostan-6-one. Anzuroside is the 24-O--D-glucopyranoside of anzurogenin C.Institute of the Chemistry of Plant Substances, Uzbek SSR Academy of Sciences, Tashkent. Translated from Khimiya Prirodnykh Soedinenii, No. 4, pp. 505–510, July–August, 1989.