Reconstruction of mitochondrial cytochrome P450-dependent steroid hydroxylases in artificial phospholipid membranes: studies of cytochrome P450scc topology by limited proteolysis

Highly purified cytochrome P450scc from bovine adrenal cortex mitochondria was inserted in artificial phospholipid membranes prepared from phosphatidylcholine to study the main principles of its membrane organization in the model system. Topology of the cytochrome P450scc polypeptide chain in proteoliposomes was studied by limited proteolysis with trypsin or chymotrypsin followed by immunochemical identification of the products of proteolysis products of the membrane-bound heme protein. It is shown that limited proteolysis of cytochrome P450scc in proteoliposomes results in a significant decrease of Vmax for the reaction of cholesterol hydroxylation to pregnenolone in the reconstituted system in the presence of exogenously added adrenodoxin-reductase and adrenodoxin. However, after proteolytic modification of cytochrome P450scc with trypsin and chymotrypsin the affinity of the heme protein to adrenodoxin is increased. Different models of membrane organization as well as functional specificity of cytochrome P450scc in artificial membranes are discussed.     

Resonance features of the allowed and forbidden bands of the microwave photonic crystal with periodicity defects

The resonance features of the allowed and forbidden bands of the microwave waveguide photonic crystals with periodicity defects are theoretically and experimentally analyzed. It is demonstrated that the number of resonances in the allowed band is determined by the number of identical elements whose periodic sequence determines the photonic crystal and the maximum Q factor is reached in the vicinity of the lower and upper boundaries of the allowed band. An increase in the size of the forbidden bands and a decrease in the size of the allowed bands of the microwave photonic crystal due to a decrease in the number of resonances in the allowed band are caused by violations of periodicity of the photonic crystal related to nonidentity of a single element.     

Automated Grain-Metric and Morphological Testing of Diamond Grinding Powders

The paper considers basic aspects of automation of morphological and grain-metric tests of diamond micropowders. The problem of automation of such tests has been solved. An optical package for an automated testing system and an algorithm for image processing have been suggested. Some information concerning fabrication and operational characteristics of experimental samples for the automated system for grain-measuring and morphological tests of diamond grinding powders is given.     

Oil coolers of turboexpansion engines of cryogenic installations made of tubes with transverse perforated ribbing

Translated from Khimicheskoe i Neftyanoe Mashinostroenie, No. 9, pp. 13–14, September, 1989.     

Remote Control of the Surface Movement of an Object Using a Two-Channel SHF Autodyne Generator

Journal of Communications Technology and Electronics - In this paper, we describe a method for restoring reflector motion using a radio-wave signal from a super high frequency (SHF) autodyne...