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121.
Cryptosporidium parvum is an increasingly recognized agent of intestinal infection in normal and immunocompromised humans, and in many other animals. The intraepithelial cell infection results in villous atrophy, mild submucosal inflammation, reduction of brush-border enzymes and a characteristic persistent watery diarrhea. The infection is self-limiting in immunocompetent hosts, probably because of specific acquired immunity; specific serum and secretory antibody responses develop that may be required for clearance and protection against reinfection. Passive milk antibody, especially i f in high titers, may be partially protective but severe, persistent infection in athymic rodents and humans with AIDS demonstrate that T cells are essential for controlling the infection. Specific anti-bodies and lymphocyte extracts have been tested in cases of cryptosporidiosis but the interpretation of the results remains controversial. Here, Shu-Xian Zu, Guo-Dong Fang, Ronald Foyer and Richard Guerrant emphasize that effective treatment and prevention remain dependent on advances in our understanding of the host cell-parasite relationship. 相似文献
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Stress‐Relieved Nanowires by Silicon Substitution for High‐Capacity and Stable Lithium Storage 下载免费PDF全文
Ting He Jianrui Feng Yan Zhang Lianhai Zu Guichang Wang Yan Yu Jinhu Yang 《Liver Transplantation》2018,8(14)
Silicon is promising as a high energy anode for next‐generation lithium‐ion batteries. However, severe capacity fading upon cycling associated with huge volume change is still an obstacle for silicon toward practical applications. Herein, the authors report that Si‐substituted Zn2(GeO4)0.8(SiO4)0.2 nanowires can effectively suppress volume expansion effect, exhibiting high specific capacity (1274 mA h g?1 at 0.2 A g?1 after 700 cycles) and ultralong cycling stability (2000 cycles at 5 A g?1 with a capacity decay rate of 0.008% per cycle), which represents outstanding comprehensive performance. The superior performance is ascribed to the substitution of Si atom that imparts to the nanowires not only high reactivity and reversibility, but also the unique stress‐relieved property upon lithiation which is further confirmed by detailed density‐functional theory computation. This work provides a new guideline for designing high‐performance Si‐based materials toward practical energy storage applications. 相似文献
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Inactivation of immobilized penicillin acylase has been studied in the presence of substrate (penicillin G) and products (phenylacetic acid and 6-aminopenicillanic acid), under the hypothesis that substances which interact with the enzyme molecule during catalysis will have an effect on enzyme stability. The kinetics of immobilized penicillin acylase inactivation was a multistage process, decay constants being evaluated for the free-enzyme and enzyme complexes, from whose values modulation factors were determined for the effectors in each enzyme complex at each stage. 6-Aminopenicillanic acid and penicillin G stabilized the enzyme in the first stage of decay. Modulation factors in that stage were 0.96 for penicillin G and 0.98 for 6-aminopenicillanic acid. Phenylacetic acid increased the rate of inactivation in both stages, modulating factors being -2.31 and -2.23, respectively. Modulation factors influence enzyme performance in a reactor and are useful parameters for a proper evaluation. (c) 1996 John Wiley & Sons, Inc. 相似文献
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重组[B18Ile]人胰岛素的鉴定和特征 总被引:4,自引:2,他引:2
突变体「B18Ile」猪胰岛素前体经分离纯化,转肽,得到重组「B18Ile」人胰素「B18Ile」人胰岛素能结晶,其与受体的结合能力为猪胰岛素的82%,保留了与猪胰岛素基本相同的体内活力,从本文结果和分析表明B18Val可能不是胰岛素表现生物功能所必需的。 相似文献
126.
Zhi Wang Longxiang Wu Shiyu Tong Xiheng Hu Xiongbing Zu Yuan Li 《Animal cells and systems.》2016,20(2):77-85
Resveratrol possesses a wide spectrum of pharmacological properties and has been an ideal alternative drug for the treatment of different cancers, including prostate cancer. However, the mechanisms by which resveratrol inhibits the growth of prostate cancer are still not fully elucidated. To understand the effect of resveratrol on the apoptosis and the epithelial-to-mesenchymal transition (EMT) of prostate cancer as well as its related mechanism, we investigated the potential use of resveratrol in PC-3 prostate cancer cells in vitro using real-time PCR, fluorescence-activated cell sorting, Western blotting, etc. Resveratrol suppresses the PC-3 prostate cancer cell growth and induces apoptosis. Resveratrol also influences the expression of EMT-related proteins (increased E-cadherin and decreased Vimentin expression). Finally, resveratrol also suppressed Akt phosphorylation in PC-3 cells. This study indicates that resveratrol may be a potential anti-cancer treatment for prostate cancer; moreover, it provides new evidence that resveratrol suppresses prostate cancer growth and metastasis. 相似文献
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Two new species and one new record species of Rhopus (Hymenoptera: Encyrtidae) from China,with a key to Chinese species 下载免费PDF全文
Rhopus antennalis sp. nov. and R. qingdaoensis sp. nov. are described as new to science and R. nigroclavatus (Ashmead, 1902) is first recorded from China. A key to all the known Chinese species of the genus also presented. 相似文献