12 research outputs found
Using of Magnetron Sputtering for Biocompatible Composites Creating
Biocompatible composites obtained using the magnetron sputtering for the production of minimally invasive implantation medical devices (stents) were investigated. Nano- and microdimensional surface layers of Ta, Ti, Ag, and Cu on flat and wire NiTi, Cu, Ti, and SiO2 substrates were created. The phase composition, surface morphology, and the layer-by-layer composition were investigated on an X-ray diffractometer, SEM, and Auger spectrometer. It was shown that the thickness and the structure of surface layers were affected by the sputtering distance, time, power, and the bias voltage at the substrate. The presence of the transition layer that contains both substrate and target elements and provides high adhesion of the surface layer to the substrate has been demonstrated. The material was tested for corrosion resistance under static conditions by dipping into solutions with various acidities (pH from 1.68 to 9.18) for 2 years, static mechanical properties, and biocompatibility in vitro and in vivo. A slight corrosive dissolution was observed only in a medium with a pH of 1.56. Dissolution in the other media is absent. An increase in strength and plasticity in comparison with substrate was attained depending on the nature of the sputtered substance and substrate. Toxicity of samples has not been revealed
Studying of the Polylactide or Polyglycylidactide Surface Layer Biodegradation in Neutral Media for the Subsequent Layered Composite Creation
The processes of biodegradation in phosphate buffer with pH 7.4 and 0.9 wt.% NaCl of polymer polylactide or polyglycylidactide films for the subsequent creation of a layered composite with a biodegradable layer on the basis of a nickel-free shape memory alloy TiNbTaZr were studied. The structure of the samples was determined by SEM and an optical microscope. For polylactide films the rate of biodegradation did not depend on the mass of the film. A gradual decrease in the rate of biodegradation at any mass with a similar dependence on time is noted. With an increase in the mass of films based on poly(glycolide-lactide) the rate of biodegradation increased. And even at the initial stage the dissolution rate is 2-3 times higher than in pure polylactide. On day 180, complete dissolution of the polyglycolidelactide was observed (even a precipitate was not observed) and completely entire polylactide films, however, lost their transparency, was noted
migration of ukrainian nationals to italy women on the move
The chapter describes the main characteristics of Ukrainian migration to Italy and the major studies of this migratory process, which is characterized by the key role of middle-aged women. Ukrainian migration is analyzed from the gender perspective and contextualized within the social, economic and political transformations involving Ukraine and Italy in recent decades. Furthermore, the main socio-demographic features of the Ukrainian presence in Italy are described from both the statistical and qualitative points of view, drawing on the most detailed and interesting studies of Ukrainian migration. In particular, the most typical profiles of Ukrainian migrant women are illustrated – "the migrant in transit" and "the permanent migrant" – to show the plurality of migration patterns and the role of structural constraints
Ecological Parameters of Outbreeding in the Interspecific Hybridization of the Common Carp
Aim. To assess the quality of offspring obtained by the method of outbreeding combination (F1), Ukrainian scaly carp with the Romanian Fresinet breeding group for the biological intensification of the ecological parameters of fishponds.Material and Methods. Serving as materials for this work were new brood-stock of cultured breeds of carp. As an improver of the indicators carp of the Romanian Fresinet breeding group obtained in crossbreeding with Ukrainian breeds of carp of heterosis combinations (F1) were used. The studies were conducted during 2014-2017 in the ponds of the Sarsky experimental farm in the May district of the Kabardino-Balkaria Republic (V Ecological-Phenological Fish Breeding Zone).Results. The study of the growth of hybrid fry of F x Ukr. scaly, Ukr. scaly x F was undertaken during 2014-2017. The resulting data shows that F x Ukr. scaly, Ukr. scaly x F hybrids are significant competitors for purebred carp. When comparing the data obtained with the results of the joint rearing of test and control carp, it is clear that the economic effect of joint rearing is very significant in terms of economy of space and artificial feed.Conclusion. Heterosis in growth and viability manifested through the crossing of carp of groups of different breeds permits us to recommend the widespread use of industrial crossbreeding of F x Ukr. scaly (inbreeding) in carp farming and particularly in regions with a high temperature range, i.e. in the North Caucasus