Modeling the process of melt solidification on the surface of a material

Translated from Prikladnaya Mekhanika i Tekhnicheskaya Fizika, No. 2, pp. 122–126, March–April, 1992.     

Adsorption and hydrogenation of unsaturated aldehydes over rhodium black

Hydrogenation selectivity of conjugated ethylenic bonds of unsaturated aldehydes over rhodium black is shown to be determined by intramolecular interactions in surface complexes due to the electronic structure of the initial unsaturated aldehydes.

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Pulsed-Spray Radiofrequency Plasma Enhanced Chemical Vapor Deposition of CuInS2 Thin Films

Thin films of CuInS₂ were grown on various substrates at a temperature of 523 K from two metal-organic precursors using radiofrequency plasma enhanced chemical vapor deposition (PECVD). Two precursor molecules, with different solubility properties, were dissolved in appropriate solvents and sprayed into the plasma region in the PECVD chamber. The resulting films were examined for atomic composition, growth rate, crystalline orientation, and uniformity. Films made from each precursor differed in thickness, atomic composition, and crystallinity. The uniformity of the film was fairly good from near the edge to the center of the substrate, and evidence for a chalcopyrite-like structure was found in several samples deposited from one of the precursor molecules.     

Oxidation-dependent effects of oxidized LDL: proliferation or cell death

Oxidized low-density lipoprotein (oxLDL) induces a wide range of cellular responses to produce atherosclerotic lesion, but key factors determining the response are not understood. In this study, purified LDL was oxidized with copper sulfate, and its physical properties and the related biological responses were investigated. The average hydrodynamic diameter of the lightly oxidized LDL was approximately 25 nm and its Rf value relative to nLDL on agarose gel was between 1.0 and 1.25. The diameter of the extensively oxidized LDL was over 30 nm, the Rf value was over 2.0. A 24 h-exposure of resting RAW264.7 macrophage cells to 100 microg/ml of the lightly oxidized LDL induced proliferation and macrophage activation whereas the extensively oxidized LDL induced cell death at the same concentration. In contrast, 200 microg/ml of oxLDL caused cell death regardless of oxidation degree. Short incubation (4-6 h) of the highly oxidized LDL (100 microg/ml) also resulted in cell proliferation. OxLDL-induced cell death showed mixed characteristics of apoptosis and/or necrosis depending on the strength and duration of the insult. These results suggest that cellular responses induced by oxLDL be dependent on the oxidation degree, the duration of exposure, and the concentration of oxLDL.     

Conformation Analysis of Ile-Ala-Val-Pro Peptide and Its Derivatives by Circular Dichroism

Ile-Ala-Val-Pro as a hypocholesterolemic peptide was isolated from soybean protein. We have synthesized four peptides, Ile-Ala-Val-Pro-Gly-Glu-Val-Ala, Leu-Ile-Ala-Val-Pro-Gly-Glu-Val-Ala, Ile-Ala-Val-Pro-Thr-Gly-Val-Ala, Leu-Ile-Ala-Val-Pro-Thr-Gly-Val-Ala, with a conserved Ile-Ala-Val-Pro amino acid sequence, for circular dichroism investigations. These four peptide sequences were also found in the amino acid sequence in soybean protein, which was defined from the genomic sequence. Additionally for a detailed analysis of conformation features of these peptides, the Ile-Ala-Val-Pro and Leu-Ile-Ala-Val-Pro were also synthesized. All peptides were prepared using standard fluorenylmethyloxycarbonyl methodology and the peptide yields ranged from 90 to 95% of the theoretical yields with purity after purification above 99%.     

Color Centers in Irradiated Potassium Picrate

The kinetics of the formation of color centers in solid potassium picrate in a -radiation field was studied. Optical spectra in potassium picrate were studied for the first time. The transmission spectra of irradiated crystals of potassium picrate displayed peaks at 515 (2,6-dinitro-para-quinone) and 630 nm (a picric acid-derived radical containing the nitrite group), with the intensity increasing with an increase in the absorbed dose. The potassium picrate radiolysis scheme is discussed.