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杨立官 《扬州教育学院学报》2003,21(1):32-35
明清时期扬州经济繁荣 ,成为全国数一数二的消费性城市。在消费时尚的追求下 ,扬州人的服饰不断趋时翻新 ,争奇斗妍 ,妇女尤甚。本文试从妇女的发式、首饰、化妆、手饰、服装、鞋袜诸方面反映明清时期扬州妇女服饰时尚 相似文献
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窦雅斌 《教学研究(河北)》2001,24(4):300-302
学校的教学应从教师为中心转变为学生为中心,让学生在学习内容、方法等方面有更大的选择余地。这样做的结果,会使学生对学习产生浓厚的兴趣,加强自信心,把握机遇,培养独立性,成为自己命运的主人。 相似文献
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存储混合型是目前研究较多的控制释放体系 ,但由于其机理较为复杂 ,目前尚未建立合理实用的动力学模型 .以混合药膜包膜体系为研究对象 ,建立了释放动力学的简化模型并获得了解析解 .实验数据表明 ,该模型适用于描述药物装填量大于饱和溶解度的药物释放动力学行为 (相对偏差小于 3 % ) .根据该模型还从理论上分析了两种限定条件 (Dm Df和 Dm Df)下药物的释放特征 :当 Dm Df时 ,释放速率变为常数 ,达到零级释放 ,其释放速率与药膜无关 ,这为零级释放缓释体系如何控制释放速率和药物释放量提供了理论依据 :当 Dm Df时 ,药物的释放速率与药膜中的释放系数、溶解度和药物的装填量有关 ,与包膜过程无关 ,其释放过程类似于混合药膜缓释体系 相似文献
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Objective: To determine the effective nucleotide sites of ribozymes against HCV, and obtain a highly effective, nontoxic and
inexpensive antisense ribozyme specific for HCV. Methods: Two effective ribozymes, targeted to HCV 5’NC region and C region,
were designed and synthesized. Eukaryotic expression vectors, pSV2-gpt. CD-SR (, containing either HCRZNC or HCRZC were constructued
and transfected into MT-2 cells, which had been infected by HCV. Quantitative PCR and hydridization were used to determine
the effect of inhibition of HCV by ribozymes. Results: HCRZNC and HCRZC suppressed the replication of HCV by 54.7% and 62.1%,
respectively. Furthermore, when both ribozymes were cotransfected into cells, they suppressed replication by 78.8%. Conclusion:
Two specific antisense ribozymes have strong inhibitory effects on the replication of HCV in cultured cells, and have better
effect when used together. 相似文献
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文章对水稻胚乳细胞发育过程、淀粉体和蛋白体结构特征与结实特性、养分输入胚乳细胞的途径、ATPase活性分布与水稻充实的关系、水稻强弱势粒胚乳细胞发育与其结实特性进行分析.提出进一步研究胚乳细胞发育及其超微结构与籽粒生理活性的关系,可从深入开展亚显微水平下强弱势粒背部维管束结构、ATPase的活性分布、差异表达基因对结实特性的影响等方面展开研究. 相似文献
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Mapping the knowledge structure exhibited by a cohort of students based on their understanding of how a galvanic cell produces energy
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This study evaluates the use of an open‐ended question to determine students' knowledge structure on the topic of galvanic cells. The open‐ended question was developed and administered to 163 Grade 10 students who had earlier completed a course on electrochemistry. Students' responses were marked as well as coded on the basis of the fields identified from their responses. This was then evaluated statistically to determine the collective knowledge structure of the sample of students. The knowledge structure thus mapped contains both canonical concepts and alternative conceptions (ACs). An important finding emerging from this study is that instructors need to focus student's attention on the dynamic processes involving electrons and ions during the operation of galvanic cells. In order for students to fully understand how a galvanic cell operates, they need to see the whole picture. There are three critical components that lead to students' understanding of how an oxidation–reduction reaction can generate energy and how a circuit is complete: transfer of electrons during oxidation–reduction half‐reactions, flow of electrons within metals, and migration of ions in solution. Also, we found that it is possible for students to use correct chemistry concepts in an incorrect way by establishing linkages among these in an inappropriate manner. We reiterate that apart from evaluating students' ACs, it is also important to evaluate the links between the concepts and conceptions present in students' knowledge structure so that teaching can be made more effective. 相似文献
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Objective: To investigate the directed transplantation of allograftic bone marrow-derived mesenchymal stem cells (MSCs) in myocardial infarcted (MI) model rabbits. Materials and Methods: Rabbits were divided into 3 groups, heart infarcted model with MSCs transplanted treatment (MSCs group, n=12), heart infarcted model with PBS injection (control group, n=20), sham operation with PBS injection (sham group, n=l 7). MSCs labelled by BrdUrd were injected into the MI area of the MSCs group. The same volume of PBS was injected into the MI area of the control group and sham group. The mortality, LVIDd, LVIDs and LVEF Of the two groups were compared 4 weeks later. Tropomyosin inhibitory component (Tn I) and BrdUrd immunohistochemistry identified the engrafted cells 4 weeks after transplantation. Result: The mortality of the MSCs group was 16.7% (2/12), and remarkably lower than the control group's mortality [35% (7/20) (P<0.05)].Among the animals that survived for 4 weeks, the LVIDd and LVIDs of the MSCs group after operation were 1.17±0.21 cm and 0.74±0.13 cm, and remarkably lower than those of the model group, which were 1.64±0.14 cm and 1.19±0.12 cm (P<0.05); the LVEF of the MSCs group after operation was 63±6%, and remarkably higher than that of the model group,which was 53±6% (P<0.05). Among the 10 cases of animals that survived for 4 weeks in the MSCs group, in 8 cases (80%),the transplanted cells survived in the non MI, MI region and its periphery, and even farther away; part of them differentiated into cardiomyocytes; in 7 cases (70%), the transplanted cells participated in the formation of blood vessel tissue in the MI region. Conclusion: Transplanted allograftic MSCs can survive and differentiate into cardiomyocytes, form the blood vessels in the MI region. MSCs transplantation could improve the heart function after MI. 相似文献
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