Mechanochemical Synthesis of Doped Apatite-type Lanthanum Silicates

In this paper, our results on mechanochemical synthesis of ATLS are summarized. The effect of the dopant type, its parent compound nature and amount of water on the Al and Fe-doped ATLS formation as well as possible phenomenological models of mechanism of apatitetype silicates synthesis are considered. As lanthanum and silicon sources, the La2O3 and SiO2∙nH2O have been taken. As dopant precursors, Fe- and Al-oxides and hydroxides, Fe(HCOO)3, SiO2 impregnated with nitrates have been taken. The apatite formation in the course of milling is studied by XRD, TEM, 29Si and 27Al MAS NMR, IR and UV-Vis spectroscopy. The key role of intermediate La(OH)3 formation, acid-base reactions and double-contact generation in the many-component mixtures due to aluminum or ferrosilicate formation for the rapid MCS of doped ATLS is shown. The doped ATLS formation via the topotactic mechanism was observed in the case of mixtures containing Al(OH)3 and SiO2 impregnated with nitrates. The water presence favours fast passing of acid-base reactions, however a large quantity of water may lead to ATLS formation via the activated mixture amorphization

Influence of the high-power ion-beam irradiation of a hydroxyapatite target on the properties of formed calcium phosphate coatings

The physical-mechanical of properties of biocompatible calcium phosphate coatings deposited onto titanium and silicon substrates from erosion materials, which are generated by irradiating hydroxyapatite (synthetic and natural) targets by means of the high-power pulsed ion beam of a Temp-4 accelerator, are investigated. A calculation technique for predicting the rate and energy efficiency of deposition using pulsed ion beams is proposed. Their characteristics are analyzed as applied to the formation of calcium phosphate coatings

Влияние физических, химических и биологических манипуляций на поверхностный потенциал кальций-фосфатных покрытий на металлических подложках

The electret voltage indices of artificial surfaces are dependent on coatings formation technology and may be regulated by means of change in their physical-chemical parameters. Chemical modification of radio frequency magnetron calcium phosphate coatings (RFMCPC) by means of silicious incorporation led to an augmentation of pieces’ electrostatic potential. A complication of RFMCPC relief that was fixed by roughness index Ra is accompanied by increase in electret voltage index of artificial surface and its statistical deviation. Bone marrow cells suspension in model biological electrolyte populated RFMCPC dimples. In this manner it modulated the amplitude and leveled out the differences of surface electrostatic potential.Показатели потенциала электростатического поля искусственных поверхностей зависят от технологии нанесения покрытий и могут регулироваться через изменение их физико-химических параметров. Химическая модификация высокочастотных (ВЧ) магнетронных кальций-фосфатных (КФ) покрытий посредством введения силикат-иона приводила к возрастанию электростатического потенциала изделий. Усложнение рельефа ВЧ-магнетронных КФ покрытий, зафиксированное по росту индекса шероховатости Ra, сопровождалось увеличением электретного потенциала поверхности и его статистической девиации. Взвесь клеток костного мозга в модельном биологическом электролите заполняла углубления КФ покрытий и, таким образом, модулировала амплитуду и выравнивала различия их поверхностного электростатического потенциала

Characterization of Aeromonas and Vibrio species isolated from a drinking water reservoir

Aims: To study the phenotypic and chemotaxonomic (i.e. phospholipid and cellular fatty acid composition) characteristics of environmental Aeromonas spp. and Vibrio spp. isolated from a drinking water reservoir near Vladivostok City, and the application of some chemotaxonomic markers for discrimination of the two genera and species. Methods and Results: Presumptive Aeromonas species were dominant in surface water samples (up to 25% of the total number of bacteria recovered). These strains were consistent with respect to the cultural and biochemical properties used to define the species Aeromonas sobria (seven strains) and Aer. popoffii (three strains). Vibrio mimicus (two strains) and Vibrio metschnikovii (one strain) were identified according to phenotypic features and cellular fatty acid composition. Conclusions: Environmental Aer. sobria isolates were atypical in their ability to grow at 42°C, and were haemolytic, proteolytic and cytotoxic. Although it was present in a high proportion in the water samples, atypical Aer. sobria is not an indicator of polluted water. Significance and Impact of the Study: The incidence of Aeromonas in the drinking water reservoirs in the Far East of Russia is reported for the first time

The influence of physical, chemical and biological manipulations on surface potential of calcium phosphate coatings on metal substrates

The electret voltage indices of artificial surfaces are dependent on coatings formation technology and may be regulated by means of change in their physical-chemical parameters. Chemical modification of radio frequency magnetron calcium phosphate coatings (RFMCPC) by means of silicious incorporation led to an augmentation of pieces’ electrostatic potential. A complication of RFMCPC relief that was fixed by roughness index Ra is accompanied by increase in electret voltage index of artificial surface and its statistical deviation. Bone marrow cells suspension in model biological electrolyte populated RFMCPC dimples. In this manner it modulated the amplitude and leveled out the differences of surface electrostatic potential

Surface modification of Ti6Al4V alloy scaffolds manufactured by electron beam melting

In this paper, the results of the surface functionalization of the Ti6Al4V alloy scaffolds with different structures for use as a material for medical implants are presented. Radio frequency magnetron sputtering was used to modify the surface of the porous structures by deposition of the biocompatible hydroxyapatite (HA) coating with the thickness of 86050 nm. The surface morphology, elemental and phase composition of the HA-coated scaffolds were studied. According to energy-dispersive X-ray spectroscopy, the stoichiometric ratio of Ca/P for flat, orthorhombic and cubic scaffolds is 1.65, 1.60, 1.53, respectively, which is close to that of stoichiometric ratio for HA (Ca/P = 1.67). It was revealed that this method of deposition makes it possible to obtain the homogeneous crystalline coating both on the dense sample and in the case of scaffolds of complex geometry with different lattice cell structure.