Corrosion Rate and Mechanism of Degradation of Chitosan/TiO Coatings Deposited on MgZnCa Alloy in Hank's Solution.

Overly fast corrosion degradation of biodegradable magnesium alloys has been a major problem over the last several years. The development of protective coatings by using biocompatible, biodegradable, and non-toxic material such as chitosan ensures a reduction in the rate of corrosion of Mg alloys in simulated body fluids. In this study, chitosan/TiO nanocomposite coating was used for the first time to hinder the corrosion rate of Mg19Zn1Ca alloy in Hank's solution.

Corrosion Resistance of MgZn Alloy Covered by Chitosan-Based Coatings.

Chitosan coatings are deposited on the surface of Mg20Zn magnesium alloy by means of the spin coating technique. Their structure was investigated using Fourier Transform Infrared Spectroscopy (FTIR) an X-ray photoelectron spectroscopy (XPS). The surface morphology of the magnesium alloy substrate and chitosan coatings was determined using Scanning Electron Microscope (FE-SEM) analysis.

Caldanaerobacter uzonensis sp. nov., an anaerobic, thermophilic, heterotrophic bacterium isolated from a hot spring.

An anaerobic thermophilic bacterium, strain K67(T), was isolated from a terrestrial hot spring of Uzon Caldera, Kamchatka Peninsula. Analysis of the 16S rRNA gene sequence revealed that the novel isolate belongs to the genus Caldanaerobacter, with 95 % 16S rRNA gene sequence similarity to Caldanaerobacter subterraneus subsp. subterraneus SEBR 7858(T), suggesting that it represents a novel species of the genus Caldanaerobacter.

[The thermophilic bacteria hydrolyzing agar: characterization of thermostable agarase].

Three strains of anaerobic thermophilic bacteria capable of growing on agarose as a source of energy and carbon were isolated from hot springs near Lake Baikal (Barguzin National Park) and the caldera Uzon (Kamchatka). Cells of all the three strains were spore bacilli with peritrichous flagellation. These isolates grew at a temperature of 55-60 degrees C and pH 6.