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141.
《科学通报(英文版)》1999,44(19):1737-1737
Being the functional basis of neural networks, neuronal signal integration has been currently becoming a hot point of neuroscience research. Active and passive membrane properties of retinal bipolar cells, temporal and spatial distribution of synaptic inputs to these cells are described, and modulation of signal integration characteristics of these cells under different retinal adaptation states is analyzed. In consideration of the functional and morphological properties of retinal bipolar cells, it is suggested that they may be an appropriate model for the study of neuronal signal integration.  相似文献   
142.
差分方程△xn=rn(-xn pe^-rxn-k),n=0,1,2,…,用来描述红血球生长规律,运用迭代法给出了保证方程每一正解{xn}趋于正平衡点的一族充分条件,所得结果不仅异于已知结论,并且文中推论改进了已有定理。  相似文献   
143.
Summary The induction of unresponsiveness to mycobacterial adjuvant took a longer time in male DA rats than in female rats. A shift in the induction time of unresponsiveness in males toward the female type was brought about by castration, but could be reverted to the male type by the application of testosterone. The transfer study revealed that cells capable of preventing arthritis required a longer incubation time for their development in males than in females. This suggests that testosterone inhibits the development of suppressor cells in adjuvant arthritis.Acknowledgments. We are grateful to The Naito Foundation Research Grant for 1983.  相似文献   
144.
IntroductionThe tumor- associated antigen,epithelial celladhesion molecule (Ep- CAM ) ,defined by themurine m Ab1 7- 1 A,is expressed on the surface ofvarious types of normal and malignant humanepithelial tissues,which makes it an attractivetarget for immunotherapy[15] . Adjuvantimmunotherapy treatment with the m Ab 1 7- 1 Asuccessfully reduced the 5 - year mortality andrecurrence rate among colorectal cancer patientswith minimal residual disease[6 ] . Studies on Ep- CAM,alias 1 7- 1 A a…  相似文献   
145.
沈承  曹广益  朱新坚 《系统仿真学报》2002,14(7):836-838,843
针对现有的熔融碳酸盐燃料电池(MCFC)模型过于复杂的弊端,本文应用RBF神经网络辨识方法建立了MCFC的温度非线性模型。简要分析了MCFC电堆的温度特性,讨论了应用RBF神经网络进行多输入/多输出非线性系统建模的主要问题,并详细给出了其辨识结构,算法和模型训练方案,应用仿真对建模的有效性和建模精度进行了检验,并与BP神经网络辨识的效果进行了对比,仿真结果证明RBF神经网络远比BP神经网络收敛得快,应用RBF神经网络辨识方法对MCFC电堆建模是可行的,它避免了用复杂的微分方程组来描述MCFC,通过神经网络可快速地得到其输入同特性,它为MCFC温度的在线预测和在线控制奠定了基础。  相似文献   
146.
Summary Peptidylarginine (protein-L-arginine) deiminase activities have been demonstrated in extracts of rat and mouse peritoneal macrophages, bone marrow cells, splenic adherent cells, neutrophils, and mouse monocyte/macrophage cell lines. The enzyme in these cells is indistinguishable from the skeletal muscle enzyme with respect to immunochemical properties.  相似文献   
147.
The invasion of cytotrophoblast cells into the maternal endometrium during embryonic implantation is very similar to the metastasis of carcinoma cells. However, the significant difference is that the former is a highly controlled process. In this report, the effects of integrin αvβ3 on the secretion of matrix metalloproteinase (MMP) were compared between normal cytotrophoblast cells and choriocarcinoma cells by RT-PCR, gelatin zymography and immunocytochemistry. The results reveal that both normal cytotrophoblast cells and choriocarcinoma cells can express integrin αvβ3. The secretion of MMPs in normal cytotrophoblast ceils is up-regulated by anti-αvβ3 antibody, whereas, decreased in choriocarcinoma cells. It was suggested that αvβ3 can modulate the expression of MMPs in trophoblasts, and this action is carried out through distinct mechanisms in normal and carcinoma cytotrophoblast cells.  相似文献   
148.
影响固定化里氏木霉合成纤维素酶的动力学因素   总被引:3,自引:0,他引:3  
对影响固定化里氏木霉细胞合成纤维素酶的主要动力学进行了研究。以纸浆为主要碳源,采用固定化细胞,在250mL摇瓶中重复分批发酵,结果表明,在一批加料条件下,适宜于固定化细胞产酶的条件是:纸浆浓度1.5%~2.0%,C/N为8,培养液的初始pH值4.0摇瓶转速200r/min及26℃。分批添加纸浆可以减少固体底物对氧气输送和物质扩散等方面造成的不良影响,有利于增加底物的总用量,从而促进纤维素酶的合成,  相似文献   
149.
Summary The ratio of sinusoidal nonparenchymal cells to hepatocytes in rat liver was significantly increased following induction of inflammation, and decreased after subsequent exposure to endotoxin, particularly in the region around the terminal portal venules. Rats with inflammatory lesions were more sensitive to endotoxin hepatocytotoxicity than normal controls, as judged from the dose-dependent increase in activity of serum transaminases and from the extent of liver tissue injury. In addition, these animals, which were already in a state of depletion of hepatic glycogen, demonstrated marked hyperglycemia 24 h after endotoxin administration in small doses of less than 2 mg/kg.  相似文献   
150.
 CD4+CD25+FOXP3+调节性T细胞(Treg)负责维持机体免疫稳态、调节免疫耐受。Treg细胞通过调控机体对外来或自身抗原的免疫应答水平,在抗自身免疫及抗肿瘤免疫中均发挥重要作用。深入分析了Treg细胞功能的分子机理,通过FOXP3+Treg细胞体外扩增或对其进行修饰改造,可以使其在不同组织及炎症微环境下特异性促进对机体的有益作用,减少副作用,这一现象会为免疫细胞治疗提供新思路与新策略。  相似文献   
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