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排序方式: 共有395条查询结果,搜索用时 15 毫秒
81.
WU Xiao-juan ZHU Xin-jian CAO Guang-yi TU Heng-yong 《浙江大学学报(A卷英文版)》2007,8(9):1505-1509
The solid oxide fuel cell (SOFC) is a nonlinear system that is hard to model by conventional methods. So far,most existing models are based on conversion laws,which are too complicated to be applied to design a control system. To facilitate a valid control strategy design,this paper tries to avoid the internal complexities and presents a modelling study of SOFC per-formance by using a radial basis function (RBF) neural network based on a genetic algorithm (GA). During the process of mod-elling,the GA aims to optimize the parameters of RBF neural networks and the optimum values are regarded as the initial values of the RBF neural network parameters. The validity and accuracy of modelling are tested by simulations,whose results reveal that it is feasible to establish the model of SOFC stack by using RBF neural networks identification based on the GA. Furthermore,it is possible to design an online controller of a SOFC stack based on this GA-RBF neural network identification model. 相似文献
82.
研究了没食子儿茶素没食子酸酯(EGCG)对人肝癌细胞BEL-7402增殖凋亡及对信号转导蛋白和转录激活因子3(Stat3)蛋白及磷酸化Stat3蛋白表达的影响.应用MTT法检测不同浓度EGCG对BEL-7402细胞增殖的抑制作用,用流式细胞仪分析细胞的凋亡率,用ELISA方法检测EGCG对Stat3蛋白及磷酸化的Stat3蛋白表达的影响.结果表明:EGCG有抑制肝癌细胞增殖促进凋亡的作用,并呈剂量依赖性.ELISA结果显示EGCG能降低磷酸化Stat3蛋白的表达水平.EGCG能抑制肝癌细胞的增殖促进凋亡,其机制可能有与下调磷酸化的Stat3蛋白的表达有关. 相似文献
83.
杨晓蕾 《山东教育学院学报》2012,27(2)
1型糖尿病是把自身免疫系统对胰岛β细胞进行特异性损伤作为特征的自身免疫疾病,其中β细胞自身抗原,T淋巴细胞,B淋巴细胞及巨噬细胞对胰岛β细胞的损伤起重要作用。 相似文献
84.
Nurul Akidah BAHARUDDIN Hamimah Abd RAHMAN Andanastuti MUCHTAR Abu Bakar SULONG Huda ABDULLAH 《浙江大学学报(A卷英文版)》2013,14(1):11-24
Solid oxide fuel cells(SOFCs) offer high energy conversion,low noise,low pollutant emission,and low processing cost.Despite many advantages,SOFCs face a major challenge in competing with other types of fuel cells because of their high operating temperature.The necessity to reduce the operational temperature of SOFCs has led to the development of research into the materials and fabrication technology of fuel cells.The use of composite cathodes significantly reduces the cathode polarization resistance and expands the triple phase boundary area available for oxygen reduction.Powder preparation and composite cathode fabrication also affect the overall performance of composite cathodes and fuel cells.Among many types of cathode materials,lanthanum-based materials such as lanthanum strontium cobalt ferrite(La1-xSrxCo1-yFeyO3- have recently been discovered to offer great compatibility with ceria-based electrolytes in performing as composite cathode materials for intermediate-to low-temperature SOFCs(IT-LTSOFCs).This paper reviews various ceria-based composite cathodes for IT-LTSOFCs and focuses on the aspects of progress and challenges in materials technology. 相似文献
85.
86.
Ferenc Torma Zoltan Gombos Marcell Fridvalszki Gergely Langmar Zsofia Tarcza Bela Merkely Hisashi Naito Noriko Ichinoseki-Sekine Masaki Takeda Zsolt Murlasits Peter Osvath Zsolt Radak 《运动与健康科学(英文)》2021,10(4):470-477
BackgroudBlood flow restriction (BFR) with low-intensity resistance training has been shown to result in hypertrophy of skeletal muscle. In this study, we tested the hypothesis that BFR during the rest periods between acute, high-intensity resistance exercise sessions (70% of 1 repetition maximum, 7 sets with 10 repetitions) enhances the effects of the resistance training.MethodsA total of 7 healthy young men performed squats, and between sets BFR was carried out on one leg while the other leg served as a control. Because BFR was applied during rest periods, even severe occlusion pressure (approximately 230 mmHg), which almost completely blocked blood flow, was well-tolerated by the participants. Five muscle-specific microRNAs were measured from the biopsy samples, which were taken 2 h after the acute training.ResultsDoppler data showed that the pattern of blood flow recovery changed significantly between the first and last BFR. microRNA-206 levels significantly decreased in the BFR leg compared to the control. The mRNA levels of RAC-β serine/threonine-protein kinase v22, nuclear respiratory factor 1, vascular endothelial growth factor, lupus Ku autoantigen protein p70 genes (p < 0.05), and paired box 7 (p < 0.01) increased in the BFR leg. The protein levels of paired box 7, nuclear respiratory factor 1, and peroxisome proliferator-activated receptor γ coactivator 1α did not differ between the BFR leg and the control leg.ConclusionBFR, during the rest periods of high-load resistance training, could lead to mRNA elevation of those proteins that regulate angiogenesis, mitochondrial biogenesis, and muscle hypertrophy and repair. However, BFR also can cause DNA damage, judging from the increase in mRNA levels of lupus Ku autoantigen protein p70. 相似文献
87.
彭南生 《邵阳学院学报(社会科学版)》1997,(2)
本文考虑多滞量的红血球生存模型 dN(t)/dt=-μN(t) sum from n=1 to m(P_ie-r_iN(t-r_i),t≥0建立了其正平衡N是全局吸引子的充分条件,推广和改进了文献[1~3]中相应的结果. 相似文献
88.
89.
Yixian QUAH Nor Ismaliza MOHD ISMAIL Jillian Lean Sim OOI Yang Amri AFFENDI Fazilah ABD MANAN Lai-Kuan TEH Fai-Chu WONG Tsun-Thai CHAI 《Journal of Zhejiang University. Science. B》2019,(1):59-70
目的:纯化和鉴定软珊瑚Sarcophyton glaucum蛋白水解物中的细胞毒性肽。创新点:首次从软珊瑚S. glaucum中发现具有癌细胞毒性的寡肽,开发了一种有潜力的新型抗癌药物。方法:通过碱性蛋白酶、胰凝乳蛋白酶、木瓜蛋白酶和胰蛋白酶产生软珊瑚S. glaucum蛋白质水解物,并通过MTT法评估其对人宫颈癌HeL a细胞的毒性。通过膜超滤、凝胶过滤色谱、固相萃取和反相高效液相色谱等技术进一步提纯肽;采用从头测序法(de novo sequencing)进行肽鉴定;根据所鉴定的序列,进一步确定合成肽的细胞毒性。结论:从软珊瑚S. glaucum的木瓜蛋白酶水解物中鉴定出三种新型肽序列:AGAPGG、AERQ和RDTQ(分子量分别为428.45、502.53和518.53 Da)。此三种寡肽具有对HeLa的细胞毒性,其半最大效应浓度(EC50)值各为8.6、4.9和5.6 mmol/L,为抗癌药物5-氟尿嘧啶的3.3、5.8和5.1倍。当测试对非癌细胞Hek293的毒性时,这三种肽仅显示16%、25%和11%的细胞毒性。因此,AERQ、AGAPGG和RDTQ有很大的潜力成为肽类抗癌药物。 相似文献
90.
BackgroundSuper-paramagnetic iron oxide nanoparticles (SPION) contain a chemotherapeutic drug and are regarded as a promising technique for improving targeted delivery into cancer cells.ResultsIn this study, the fabrication of 5-fluorouracil (5-FU) was investigated with loaded Dextran (DEX-SPION) using the co-precipitation technique and conjugated by folate (FA). These nanoparticles (NPs) were employed as carriers and anticancer compounds against liver cancer cells in vitro. Structural, magnetic, morphological characterization, size, and drug loading activities of the obtained FA-DEX-5-FU-SPION NPs were checked using FTIR, VSM, FESEM, TEM, DLS, and zeta potential techniques. The cellular toxicity effect of FA-DEX-5-FU-SPION NPs was evaluated using the MTT test on liver cancer (SNU-423) and healthy cells (LO2). Furthermore, the apoptosis measurement and the expression levels of NF-1, Her-2/neu, c-Raf-1, and Wnt-1 genes were evaluated post-treatment using flow cytometry and RT-PCR, respectively. The obtained NPs were spherical with a suitable dispersity without noticeable aggregation. The size of the NPs, polydispersity, and zeta were 74 ± 13 nm, 0.080 and −45 mV, respectively. The results of the encapsulation efficiency of the nano-compound showed highly colloidal stability and proper drug maintenance. The results indicated that FA-DEX-5-FU-SPION demonstrated a sustained release profile of 5-FU in both phosphate and citrate buffer solutions separately, with higher cytotoxicity against SNU-423 cells than against other cells types. These findings suggest that FA-DEX-SPION NPs exert synergistic effects for targeting intracellular delivery of 5-FU, apoptosis induction, and gene expression stimulation.ConclusionsThe findings proved that FA-DEX-5-FU-SPION presented remarkable antitumor properties; no adverse subsequences were revealed against normal cells.How to cite: Mahdia SA, Kadhimb AA, Albukhaty S, et al. Gene expression and apoptosis response in hepatocellular carcinoma cells induced by biocompatible polymer/magnetic nanoparticles containing 5-fluorouracil. Electron J Biotechnol 2021;52. https://doi.org/10.1016/j.ejbt.2021.04.001 相似文献