ЭКСПЕРИМЕНТАЛЬНАЯ ОЦЕНКА КОМПОЗИЦИОННОГО МАТЕРИАЛА НА ОСНОВЕ БЕЛКОВО-МИНЕРАЛЬНЫХ КОМПОНЕНТОВ И РЕКОМБИНАНТНОГО КОСТНОГО МОРФОГЕНЕТИЧЕСКОГО БЕЛКА-2 В КАЧЕСТВЕ ПОКРЫТИЯ ТИТАНОВЫХ ИМПЛАНТАТОВ

The influence of both, the composite material based on the protein-mineral components including the prolonged form of the recombinant human bone morphogenetic protein 2 (rhBMP-2) and the method of the titanium implant’s surface treatment, on the reparative osteogenesis and adhesion strength of the bone tissue – implant’s surface contact was evaluated. Covering of implants with the composite coating promotes significant acceleration of the bone tissue regeneration processes in the site of implants loading. The composition coating with prolonged form of the rhBMP-2 promoted increasing of the neogenic bone tissue’s adhesion with the implants, as compared with the coating without recombinant human bone morphogenetic protein. The implants treated with microarc oxidation demonstrated higher values of the breakout force during the separation of the implants from the bone than the implants treated with sandblasting method.Проведена оценка влияния композиционного материала на основе белково-минеральных компонентов, содержащего пролонгированную форму рекомбинантного костного морфогенетического белка-2 человека (rhВМР-2), и способа обработки поверхности титанового имплантата на репаративный остеогенез и адгезионную прочность контакта костной ткани с поверхностью имплантата. Нанесение на имплантаты композиционного препарата/покрытия способствовало значительному ускорению процессов регенерации костной ткани в месте введения имплантатов. Композиционное покрытие с пролонгированной формой rhBMP-2, способствовало увеличению адгезионных связей новообразованной костной ткани с поверхностью образцов по сравнению с покрытием, не содержащим рекомбинантного костного морфогенетического белка. Имплантаты с поверхностью, обработанной с помощью микродугового оксидирования, демонстрировали более высокие значения величины усилия отрыва имплантата от кости, чем модифицированные пескоструйной обработкой

Changes in Isotopic Composition of Metals Enriched in Hydrogen

We have studied changes in the isotopic composition of niobium and palladium as well as of titanium film structures over ceramics enriched in deuterium. We have also investigated changes in the isotopic composition of copper under thermally activated copper diffusion into nickel. An intense isotope exchange between the atoms of the matrices and impurites enriched in deuterium and changes in the isotopic composition of copper during diffusion into nickel were observed. The relationships seen in the experiments lead us to suggest that changes in the isotope ratio may be caused (along with plausible neclear transformations) by a strong isotopic effect involved in cold diffusion induced by hydrogen migration

Diffusion of Zn in nanostructured aluminum alloys produced by surface mechanical attrition treatment

After surface nanocrystallization of pure Al and a cast Al-Si alloy through surface mechanical attrition treatment (SMAT), 200- to 300-lm-thick Zn coatings were deposited on the nanostructured surface using the clod spray technique. Subsequently, diffusion of Zn into the Al substrate was induced by postspray annealing treatment at various temperatures for different times. The diffusion kinetics of Zn in the nanostructured surface layers was studied in terms of the Zn concentration profile in the substrate by using scanning electron microscopy (SEM) and electron probe microscopy analysis (EPMA). Experimental results show that not only the diffusivity of Zn in the nanocrystalline grains is significantly increased compared with the diffusion in the coarse grained counterpart, but the temperature at which noticeable Zn diffusion in Al alloys occurs is also reduced from 573 K (300 °C) in coarse-grained Al alloys to 523 K (250 °C) in nanostructured alloys. In addition, because the nanocrystalline grains produced by SMAT in Al-Si alloys are much smaller than those in pure Al due to the effect of eutectic Si, the diffusion of Zn in the SMATed Al-Si alloy is much faster than that in the SMATed pure Al. It is believed that the high diffusivity of Zn in the nanocrystalline Al grains is attributed to the large fraction of grain boundaries that act as fast diffusion channel. The effect of thermal stability of the nanocrystalline grains on Zn diffusion in the SMATed Al alloys is also discussed

An Analytical Framework for Predicting the Limit in Structural Refinement in Accumulative Roll Bonded Nickel

The limit in structural refinement of lamellar bands (LBs) generated during accumulative roll bonding (ARB) of commercially pure nickel was investigated by transmission electron microscopy and transmission Kikuchi diffraction. A typical LB consists of an internal cellular substructure of low angle boundaries (LABs) bounded by two high angle boundaries (HABs) that are aligned parallel to the rolling plane. At low true strains (e < 2.4; 1 to 3 ARB cycles), the deformation substructure was distributed heterogeneously; nano-sized (~80 nm) equiaxed grains containing mainly HABs were generated in the vicinity of the roll bonding region of the individual nickel layers, whereas a typical dislocation substructure containing LABs was generated in their interior. At high strains (e > 4.8; 6 to 10 ARB cycles), a homogenous distribution of well-defined, highly elongated LBs of average thickness 75 nm was generated throughout the entire thickness of the material. The thickness of these LBs decreased with increasing number of ARB cycles and reached a saturation thickness of ~75 nm after 6 to 8 cycles. A theoretical framework for the limit to LB refinement during ARB is presented based on the refinement rate due to the stored energy of deformation balanced by the growth rate caused by adiabatic heating. The analysis takes into account the unique features of LB structures and processing parameters