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941.
集旋转与悬浮于一体的无轴承异步电机是一个非常复杂的非线性系统,电磁转矩与径向悬浮力的非线性解耦是实现电机稳定悬浮运行的基础.为了降低控制系统对电机参数的依赖程度,本文采用定子磁场定向控制,同时为了克服此方法在低速时的不足,应用U-I法和I-ω法相结合观测定子磁通和气隙磁通,在matlab/simulink中构造了定子磁场定向控制的无轴承异步电机矢量控制系统.仿真结果表明:实现了电磁转矩与径向悬浮力之间的解耦,验证了此方法的有效性. 相似文献
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AIM: To compare 2 environments, the subrenal capsule and oral submucosa, for producing well-formed teeth from mouse tooth germs and for exploring the ideal environment for tooth regeneration. METHODS: Two groups were set up. Group A was transplanted with the mouse embronic day (ED) 14.5 first mandibular molar tooth germs into the subrenal capsule, while group B was transplanted with the ED14.5 first mandibular molar tooth germs into the oral submucosa. After 3 weeks and 4 weeks, the host mice were sacrificed, and the transplanted explants were evaluated with morphologic observation, histological structures, hardness and elastictic modulus tests, and chemical compositions. RESULTS: (1) The explants isolated from both environments showed the tooth-like structures, but as to the group B, the crown was smaller, and the shape of the cusps was not significant. (2) HE staining showed that the dentin and enamel in group A were thicker than those in group B in which the ameloblasts and odontoblasts were differentiated not very well. (3) In the test of enamel hardness, only the hardness of 4 weeks in group B was lower than normal mouse tooth. In the test of enamel modulus, the elastic modulus of enamel in 3 weeks of group A was slightly lower than normal mouse tooth, but the difference was not significant.The elastic modulus of enamel in 4 weeks of group A and group B was significantly lower than normal mouse tooth and 3 weeks of group B. The hardness and elastic modulus of dentin in 3 groups was not significant. (4) Raman spectroscopy showed 2 groups grew in harmony in general, they all had the largest peak in the point of 961 cm-1, but the 3 weeks of group B had an obvious peak in the point of 2 947 cm-1. CONCLUSION: For the development of ED14.5 tooth germs, we obtain almost the whole tooth in subrenal capsule transplantation after 3 or 4 weeks. The buccal submucosa environment still has a certain influence on the tooth germ development, although there are some differences about the tooth development between this environment and subrenal capsule environment. 相似文献
945.
ZHOU Zi-yi GAO Jun-peng XIANG Jun CHEN Yi-ping CAI Ye-feng LUO En-li CAI Ding-fang 《园艺学报》2015,31(4):659-663
AIM: To investigate the effect of triptolide on the inhibition of microglial activation in 1-methyl-4-phenyl pyridinium (MPP+)-induced hemiparkinson disease rats.METHODS: The rat model of Parkinson disease was established by intranigral injection of MPP+. The rats were randomly divided into sham group, MPP+ group, triptolide group and vehicle group. The survival of dopaminergic neurons was detected by the immunofluorescence of tyrosine hydroxylase (TH) in the substantia nigra (SN). The activation of microglia was determined by immunofluorescence of OX-42 (microglia marker) in the SN. The expression of chemokine receptor CX3CR1 in SN was measured by Western blotting.RESULTS: Intranigral injection of MPP+ increased the fluorescence intensity of the microglial marker, and promoted DA neuron degenerative death. Immunohistological analysis showed that the OX-42 density was decreased (P<0.01) and tyrosine hydroxylase (TH) positive neurons were increased in the triptolide group (P<0.01). The expression of CX3CR1 was lower in triptolide group than that in model group (P<0.05).CONCLUSION: Triptolide may improve PA neurons function in MPP+-induced rats through inhibiting CX3CR1 expression and microglial activation. 相似文献
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AIM: To investigate the expression and clinical significance of PAK4 in the cell lines and tissues of non-small cell lung cancer (NSCLC). METHODS: PAK4 expression in human bronchial epithelial (HBE) cells, NSCLC cell lines, NSCLC tissues and adjacent non-tumor tissues were assessed by immunohistochemistry, real-time PCR and Western blot. Prognostic value of PAK4 expression was evaluated by Kaplan-Meier analysis and Cox regression. RESULTS: PAK4 was over-expressed in the NSCLC cell lines at both mRNA and protein levels compared with HBE cells (P<0.05). PAK4 was over-expressed in the NSCLC tissues at both mRNA and protein levels compared with adjacent non-tumor tissues (P<0.05). PAK4 was over-expressed in the metastatic NSCLC tissues compared with the primary NSCLC tissues (P<0.05). Higher PAK4 staining scores were positively correlated with differentiation, lymph node metastasis, distant metastasis, and clinical stage. Kaplan-Meier analysis and log-rank test showed that overall survival was significantly different between the patients with up-regulated PAK4 and the patients with down-regulated PAK4(P<0.05). PAK4 over-expression was associated with NSCLC progression.CONCLUSION: Increased PAK4 expression was associated with tumor invasion, metastasis and prognosis in the patients with NSCLC. PAK4 is an important prognostic marker and potential therapeutic target in NSCLC. 相似文献
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大豆吡哆醇生物合成蛋白基因(PDX)的电子克隆和进化分析 总被引:3,自引:0,他引:3
电子克隆(In silicocloning)是随着基因组计划和EST计划实施而发展起来的利用生物信息学手段进行基因克隆的新方法。根据物种间同源基因相对保守的特点,以拟南芥(Arabidopsis thaliana)吡哆醇生物合成蛋白cDNA序列为信息探针,对大豆(Glycine max)EST数据库进行同源搜索和序列拼接,获得了1 280 bp长的大豆吡哆醇生物合成蛋白的基因序列(GenBank登陆号为DQ139265)。经过RT-PCR扩增、基因组PCR扩增、分子克隆和序列分析验证,结果表明与电子克隆序列完全一致。该基因具有完整的开放阅读框架(ORF,20~955 bp),编码311个氨基酸。通过与水稻、日本百脉根、烟草、截形苜蓿等物种的吡哆醇生物合成蛋白序列比对,发现该基因具有高度的保守性。表明根据物种间同源基因序列,对跨物种间EST数据库进行同源检索、筛选、拼接,是克隆基因的有效途径。 相似文献