<abstract>Aim: To study the expression and regulation of Smadl, Smad2 and Smad4 proteins (intracellular signaling molecules of transforming growth factor-β family) in rat testis during postnatal development. Me...<abstract>Aim: To study the expression and regulation of Smadl, Smad2 and Smad4 proteins (intracellular signaling molecules of transforming growth factor-β family) in rat testis during postnatal development. Methods: The whole testes were collected from SD rats aged 3, 7, 14, 28 and 90 (adult) days. The cellular localization and developmental changes were examined by immunohistochemistry ABC method with the glucose oxidase-DAB-nickel enhancement technique. Quantitative analysis of the immunostaining was made by the image analysis system. The Smads proteins coexistence in the adult rat testis was tested by the double immune staining for CD14-Smad4 and Smad2-Smad4. The protein expression of Smad during rat testicular development was examined by means of Western blots. Results: Smadl, Smad2 and Smad4 were present throughout testicular development. The immunostaining of Smadl and Smad2 were present in spermatogenic cells. A positive immunoreactivity was located at the cytoplasm, but the nucleus was negative. Smadl was immunolocalized at the d14, d28 and adult testes, while Smad2, at the d7, d14, d28 and adult testis. There was positive irnmunoreaction in the Sertoli cells and Leydig cells as well. The immunolocalization of Smad4 was exclusively at the cytoplasm of Leydig cells and the nuclei were negative throughout the testicular development. No expression was detected in the germ cells. The results of image and statistical analysis showed that generally the expression of Smadl, Smad2 and Smad4 in the testis tended to increase gradually with the growth of the rat. Conclusion: The present data provide direct evidences for the molecular mechanism of TGF-βaction in rat testes during postnatal development and spermatogenesis.展开更多
A mathematical model of single char particle combustion in circulating fluidized bed combustor (CFBC)is developed in this paper. Its numerical solution in operating conditions of CFBC verifies the nature of a phenomen...A mathematical model of single char particle combustion in circulating fluidized bed combustor (CFBC)is developed in this paper. Its numerical solution in operating conditions of CFBC verifies the nature of a phenomenon that the distribution of carbon content of char particles has a peak value versus their diameters. The results show that the temperature of smaller char particle is close to the bed temperature, and there also exits a peak value for the burn-out time of char particles versus their diameters.The countermeasures are presented to improve combustion of fine particles, such as use of the fly-ash recirculation, the hot cyclone, and so on.展开更多
文摘<abstract>Aim: To study the expression and regulation of Smadl, Smad2 and Smad4 proteins (intracellular signaling molecules of transforming growth factor-β family) in rat testis during postnatal development. Methods: The whole testes were collected from SD rats aged 3, 7, 14, 28 and 90 (adult) days. The cellular localization and developmental changes were examined by immunohistochemistry ABC method with the glucose oxidase-DAB-nickel enhancement technique. Quantitative analysis of the immunostaining was made by the image analysis system. The Smads proteins coexistence in the adult rat testis was tested by the double immune staining for CD14-Smad4 and Smad2-Smad4. The protein expression of Smad during rat testicular development was examined by means of Western blots. Results: Smadl, Smad2 and Smad4 were present throughout testicular development. The immunostaining of Smadl and Smad2 were present in spermatogenic cells. A positive immunoreactivity was located at the cytoplasm, but the nucleus was negative. Smadl was immunolocalized at the d14, d28 and adult testes, while Smad2, at the d7, d14, d28 and adult testis. There was positive irnmunoreaction in the Sertoli cells and Leydig cells as well. The immunolocalization of Smad4 was exclusively at the cytoplasm of Leydig cells and the nuclei were negative throughout the testicular development. No expression was detected in the germ cells. The results of image and statistical analysis showed that generally the expression of Smadl, Smad2 and Smad4 in the testis tended to increase gradually with the growth of the rat. Conclusion: The present data provide direct evidences for the molecular mechanism of TGF-βaction in rat testes during postnatal development and spermatogenesis.
文摘A mathematical model of single char particle combustion in circulating fluidized bed combustor (CFBC)is developed in this paper. Its numerical solution in operating conditions of CFBC verifies the nature of a phenomenon that the distribution of carbon content of char particles has a peak value versus their diameters. The results show that the temperature of smaller char particle is close to the bed temperature, and there also exits a peak value for the burn-out time of char particles versus their diameters.The countermeasures are presented to improve combustion of fine particles, such as use of the fly-ash recirculation, the hot cyclone, and so on.
