李永康膏滋对小鼠胸腺端粒酶活性等免疫功能的影响

通过臭氧(O_3)致小鼠衰老模型,对各组抗衰老实验小鼠的生理和免疫功能进行检测,采用端粒重复序列分析(TRAP)方法检测衰老小鼠胸腺组织的端粒酶活性。李永康膏滋能使衰老小鼠爬绳、游泳和抗冻能力增强(P<0.05或P<0.01),血清总IgG浓度提高(P<0.01),脚掌发疱增重明显(P<0.01),胸腺指数增加(P<0.05或P<0.01);并使衰老小鼠胸腺端粒酶活性增强。表明李氏膏滋有延缓臭氧致小鼠衰老的作用,提高衰老小鼠体液和细胞免疫功能。使衰老小鼠胸腺端粒酶活性增强可能与该器官富含活化的淋巴细胞有关。教育部厦门大学细胞生物学和肿瘤细胞工程重点实验室开放研究基

Deformation mechanisms for superplastic behaviors in a dual-phase high specific strength steel with ultrafine grains

The superplastic behaviors of a high specific strength steel (HSSS) with dual-phase microstructure and ultrafine grains have been investigated under a temperature range of 873-973 K and at a wide strain rate range of 10(-4)-10(-1)/s. The ultrafine grained HSSS exhibits excellent superplastic properties. The microstructure observations at interrupted strains for tests under temperature of 973 K and at strain rate of 10(-3)/s have provided evidences of different mechanisms for two stages. At the first stage (strain range from 0% to 400%), the superplastic flow is attributed to the diffusional transformation from fcc austenite phase to intermetallic compound B2 phase coupled with grain boundary sliding. While intragranular dislocation activities should be the dominant mechanism for the second stage (strain range from 400% to 629%) due to the increased realistic strain rate by diffusive necking. The grain sizes of both phases are observed to be relatively stable and remain always sub micron level during the high temperature tensile deformation, facilitating the superplastic flow.</p