Thermal Stability and Mechanical Properties of Al-Al2O3 Nanocomposite Produced by Mechanical Milling and Hot-Pressing

In this study, Al-Al2O3 nanocomposite powders containing 5, 10 and 15 Wt% of nanopowder were produced by mechanical alloying. For comparing, Al-Al2O3 composite powder containing 5Wt% of micrometric Al2O3 was also produced. The powder was then hot-pressed in a mold to produce bulked parts. The effect of Al2O3 content on grain growth, density, hardness and bending strength of bulked composite was discussed and microstructures were investigated by optical, scanning and transmission electron microscopy. The results revealed that when nanometric particles were used instead of micrometric particles the grain growth was reduced, while the increase of particle weight percentage did not affect the grain growth. The results also showed that when weight percentage of nanometric particles was increased, although hardness of bulked parts was increased but relative density and bending strength was reduced severely. When you are citing the document, use the following link http://essuir.sumdu.edu.ua/handle/123456789/3493

Angiogenesis and expression of tenascin after transmural laser revascularization

Transmyocardial revascularization (TMR) with CO2-laser equipment is an alternative approach in the treatment of patients with severe ischemic cardiac disease. Several studies concerning morphological features after TMR document a strong transmyocardial injury, but little is known about wound healing in laserinduced alterations of the cardiac skeleton and their putative role for angiogenesis and endothelialization. The present study was conducted to establish a useful immunohistochemical marker for detection of these laser-induced injuries and to analyze starting points of angiogenesis in human myocardium after TMR. Our data show that tenascin labeling is a useful immunohistochemical approach to detect laser-alterated segments of the cardiac skeleton as well as laser-induced fibrosis. Starting points of the angiogenetic process are seen throughout the margins of laser-induced lesions, where myocardial capillaries are found. Disrupted vessels located within laser-alterated connective tissue septa are not major starting points for endothelialization of laser-induced lesions and for capillary sprouts. In comparison to laser-induced fibrosis, induction and promotion of angiogenesis by laser radiation is weak

Angiogenesis and expression of tenascin after transmural laser revascularization

Transmyocardial revascularization (TMR) with CO2-laser equipment is an alternative approach in the treatment of patients with severe ischemic cardiac disease. Several studies concerning morphological features after TMR document a strong transmyocardial injury, but little is known about wound healing in laserinduced alterations of the cardiac skeleton and their putative role for angiogenesis and endothelialization. The present study was conducted to establish a useful immunohistochemical marker for detection of these laser-induced injuries and to analyze starting points of angiogenesis in human myocardium after TMR. Our data show that tenascin labeling is a useful immunohistochemical approach to detect laser-alterated segments of the cardiac skeleton as well as laser-induced fibrosis. Starting points of the angiogenetic process are seen throughout the margins of laser-induced lesions, where myocardial capillaries are found. Disrupted vessels located within laser-alterated connective tissue septa are not major starting points for endothelialization of laser-induced lesions and for capillary sprouts. In comparison to laser-induced fibrosis, induction and promotion of angiogenesis by laser radiation is weak