Hydrolytic splitting of vitamin A esters in the blood]

The retinol and retinylpalmitate content along with the retinylacetate and retinylpalmitate-hydrolase in the blood of the portal vein and in the peripheral blood from the superficial vein of the hind limb of dogs was determined in chronic experiments before and 1, 2, 3 and 4 hours after administration of the vitamin A preparations into the small intestine fistula. The introduction of an oily retinylacetate solution into the fistula was attended both by an increase of the retinylpalmitate content in the blood plasma and the appearance therein of the retinyl-palmitat-hydrolase activity. Introduction of an aquous-colloidal solution of retinyl-palmitate caused a rise in the latter's content in the blood but was not accompanied by the appearance of the retinyl-palmitate-hydrolase activity. In the blood taken on an empty stomach no capacity for retinyl-palmitate hydrolysis was in evidence. It is presumed that the emergence of the retinyl-palmitate activity in the blood following introduction of precisely the oily retinylacetate solution is due to an intensified supply of the pancreatic enzymes into the blood in response to the fat load. The retinylacetate-hydrolase activity was continually present in the blood and did not vary in its intensity in the dynamics of absorption.     

Allergic contact dermatitis from ethyl sebacata in haloprogin cream

A 13-year-old girl developed contact dermatitis to haloprogin (Halotex) cream. Patch tests incriminated ethyl sebacata, a solubilizer, as the allergen. To our knowledge, this is the second reported case of contact dermatitis attributable to this substance.     

Cholesterol biosynthesis in stomach and intestinal tissue of rat

Biosynthesis of cholesterol and its precursors (metastenol, latosterol and 7-dehydrocholesterol) was studied in the mucous and serous membranes of small intestine, secretory and esophageal regions of the normal rat stomach. The content of these sterols was also determined. The intensity of sodium 2-14C-acetate incorporation into cholesterol and its precursors in the mucous membrane of the small intestine and stomach secretory region is considerably higher than into the same sterols of the serous membrane and esophageal region. Cholesterol synthesis is most intensive in the small intestine mucous membrane and stomach secretory region.     

Brass Depassivation in Neutral Chloride Media

The influence of the composition of Cu–Zn alloys and of the content of chloride ions in solution on the initial stages of brass depassivation in a borate buffer was studied. It was demonstrated that the pitting resistance of brasses decreases from to ( + ) brass. The pit initiation was attributed to nucleophilic substitution of corrosive anions for the passivating species in the adsorbed complex. It was shown that pit initiation on brasses, as for copper, predominantly follows the dissociative mechanism.     

Complex amine-based reagents

Amines for a long time have been applied to maintaining water chemistry conditions (WCC) at power plants. However, making use of complex reagents that are the mixture of neutralizing and the filmforming amines, which may also contain other organic components, causes many disputes. This is mainly due to lack of reliable information about these components. The protective properties of any amine with regard to metal surfaces depend on several factors, which are considered in this article. The results of applying complex reagents to the protection of heating surfaces in industrial conditions and estimated behavior forecasts for various reagents under maintaining WCC on heat-recovery boilers with different thermal circuits are presented. The case of a two-drum heat-recovery boiler with in-line drums was used as an example, for which we present the calculated рН values for various brands of reagents under the same conditions. Work with different reagent brands and its analysis enabled us to derive a composition best suitable for the conditions of their practical applications in heat-recovery boilers at different pressures. Testing the new amine reagent performed at a CCPP power unit shows that this reagent is an adequate base for further development of reagents based on amine compounds. An example of testing a complex reagent is shown created with the participation of the authors within the framework the program of import substitution and its possible use is demonstrated for maintaining WCC of power-generating units of combined-cycle power plants (CCPP) and TPP. The compliance of the employed reagents with the standards of water chemistry conditions and protection of heating surfaces were assessed. The application of amine-containing reagents at power-generating units of TPP makes it possible to solve complex problems aimed at ensuring the sparing cleaning of heating surfaces from deposits and the implementation of conservation and management of water chemistry condition on the TPP equipment.     

Phenomenological description of doped manganites. Electron bandwidth,crystal local structure and Curie temperature

La_0.7Ca_0.3Mn_0.95M_0.05O₃ (M = Mn, Al, 0.5Al+0.5In, and In) perovskites (ABO₃) were studied with x-ray diffraction and AC susceptibility measurements. We provide the phenomenological expressions for the electron bandwidth, W, and Curie temperature, T_C, to describe the variance in these values caused by the change of the degree of doping in the A- position and of the type of dopant in the B-position. The observed decrease in T_C with doping is found to be mostly related to the difference in the electron configuration of Mn³⁺ ions and dopant M, and partially caused by the change in the local crystal structure because of the difference in the Mn³⁺- and M-ion radii.     

Thermally Activated Brown and Black Coals as the Sorbents of Chromium(VI) from Aqueous Solutions

Porous materials prepared from brown and black coals were used as sorbents for the extraction of chromium(VI) from aqueous solutions. They were compared with an AG-3 commercial sorbent. The effect of the acidity of reaction medium on the adsorption of chromium(VI) was established. The extraction of Cr(VI) from aqueous solutions reached a maximum in a range of pH 1.5–2.0. A kinetic study made it possible to determine equilibration times in the porous material–chromium(VI) solution systems.