Rheology and porosity effect on the proliferation of preosteoblast on zirconia ceramics

It has been studied ZrO2(MexOy) based porous ceramics, obtained from the powders consisting of hollow spherical particles. It was shown that the structure is represented as a cellular carcass with a bimodal porosity, formed of a large pore close to a spherical shape and the pores that were not filled with the powder particles during the compaction. For such ceramics the increase of pore volume is accompanied by an increase in strain in an elastic area. It was also shown that the porous ZrO2 ceramics had no acute or chronic cytotoxicity. At the same time, ceramics possess the osteoconductive properties: adhesion support, spreading, proliferation and osteogenic differentiation of MSCs

Влияние крупномасштабных мод общей изменчивости атмосферы и океана в Атлантико-Европейском регионе на климат Беларуси

We have established the relationships of quasicyclic components in changes of air temperature and precipitation in Belarus with large-scale modes of general variability of the atmosphere and ocean in the Atlantic-European region. When the summer air temperature changes in Belarus and in Eastern Europe, a quasi-60-year oscillation is identified, which coincides in phase with the Atlantic multi-decadal oscillation. It is shown that the time series of winter air temperature in Belarus contain a quasi-8-year component synchronized with a similar component of the North Atlantic Oscillation. Moreover, the periods of acceleration and deceleration of winter warming in Belarus coincide with the upward and downward quasi-30-year phases of the North Atlantic Oscillation, respectively. The latter are also consistent with fluctuations in moisture content in Belarus and Europe. Based on the established patterns, we have concluded that the rapid rise in winter temperatures, slowing down of summer warming and deterioration in water supply in the southern regions of Belarus observed in the last decade are part of a natural cycle lasting about 30 years, developing against the background of a long-term trend of anthropogenic global warming. Установлены связи квазициклических компонент в изменении температуры воздуха и количества осадков на территории Беларуси с крупномасштабными модами общей изменчивости атмосферы и океана в Атлантико-Европейском регионе - Атлантической мультидекадной осцилляцией и Североатлантическим колебанием. В изменениях летней температуры воздуха в Беларуси и на территории Восточной Европы выделено квази-60-летнее колебание, совпадающее по фазе с Атлантической мультидекадной осцилляцией. Показано, что временные ряды зимней температуры воздуха в Беларуси содержат квази-8-летнюю компоненту, синхронизированную с аналогичной компонентой Северо-Атлантического колебания, а периоды ускорения и замедления зимнего потепления в Беларуси совпадают соответственно с восходящими и нисходящими квази-30-летними фазами Северо-Атлантического колебания. Последние также согласуются с колебаниями увлажненности территории Беларуси и Европы. Исходя из установленных закономерностей сделан вывод, что быстрый рост зимних температур, замедление темпов летнего потепления и ухудшение водообеспеченности южных регионов Беларуси, наблюдаемые в последнее десятилетие, являются частью естественного цикла длительностью около 30 лет, развивающегося на фоне долгосрочного тренда антропогенного глобального потепления

Rheology and porosity effect on the proliferation of preosteoblast on zirconia ceramics

It has been studied ZrO2(MexOy) based porous ceramics, obtained from the powders consisting of hollow spherical particles. It was shown that the structure is represented as a cellular carcass with a bimodal porosity, formed of a large pore close to a spherical shape and the pores that were not filled with the powder particles during the compaction. For such ceramics the increase of pore volume is accompanied by an increase in strain in an elastic area. It was also shown that the porous ZrO2 ceramics had no acute or chronic cytotoxicity. At the same time, ceramics possess the osteoconductive properties: adhesion support, spreading, proliferation and osteogenic differentiation of MSCs

Increasing fracture toughness of zirconia-based composites as a synergistic effect of the introducing different inclusions

The effect of multi-walled carbon nanotubes (MWCNTs) and hexagonal boron nitride (h-BN) inclusions on the fracture toughness of yttria-stabilized zirconia (YSZ) ceramics has been studied. It is shown that an increase in the MWCNTs and h-BN content has a positive effect on the K1C of zirconia ceramics. The greatest increase in the fracture toughness of YSZ ceramics was observed with the introduction of hexagonal boron nitride particles. For YSZ ceramics, the K1C value was ≈6.1 MPa m1/2, for ceramics with a 5 wt % of h-BN K1C ≈ 9.2 MPa m1/2. It was shown that an increase of the YSZ ceramics fracture toughness with the introduction of MWCNTs and h-BN, both and separately was provided by the combined action of several mechanisms of increasing the work of crack propagation. In addition, in all composites obtained in this work, the transformation of tetragonal ZrO2 into monoclinic was observed

Method of maxillofacial reconstruction using individualized implants made of bioactive ceramics

Introduction. Many researchers are currently searching for new, safe, and effective methods of maxillofacial reconstruction in cancer patients.In this case, special attention should be paid to ceramic implants.Objective: to develop a personalized approach to the maxillofacial reconstruction using bioactive ceramic implants.Materials and methods. We performed virtual planning of the implants for the reconstruction of the maxillofacial region basing on the preoperative spiral computed tomography scans of the facial skeleton.Results. We have developed a new method of preoperative planning and creation of individualized implants made of bioactive ceramics for reconstructing the maxillofacial region. This method is demanded in reconstructive surgery and can be applied in routine clinical practice.Conclusion. Reconstructive surgeries with the implants made of bioactive ceramics allow achieving good functional and aesthetic results in patients with large postoperative defects in the maxillofacial region, thus, improving their quality of life

Preparation and Properties of Iron Nanoparticle-Based Macroporous Scaffolds for Biodegradable Implants

Fe-based scaffolds are of particular interest in the technology of biodegradable implants due to their high mechanical properties and biocompatibility. In the present work, using an electroexplosive Fe nanopowder and NaCl particles 100–200 µm in size as a porogen, scaffolds with a porosity of about 70 ± 0.8% were obtained. The effect of the sintering temperature on the structure, composition, and mechanical characteristics of the scaffolds was considered. The optimum parameters of the sintering process were determined, allowing us to obtain samples characterized by plastic deformation and a yield strength of up to 16.2 MPa. The degradation of the scaffolds sintered at 1000 and 1100 °C in 0.9 wt.% NaCl solution for 28 days resulted in a decrease in their strength by 23% and 17%, respectively