目的 获得可用于动物试验和临床试验的人表皮生长因子原料药。方法 化学合成的人表皮生长因子基因在甲基营养型酵母中表达并分泌到培养基中的人表皮生长因子蛋白经 Phenysepharose 6 Fast Flow（ high sub）柱、 Q-sepharose High Perfo...目的 获得可用于动物试验和临床试验的人表皮生长因子原料药。方法 化学合成的人表皮生长因子基因在甲基营养型酵母中表达并分泌到培养基中的人表皮生长因子蛋白经 Phenysepharose 6 Fast Flow（ high sub）柱、 Q-sepharose High Performance柱、 Superdex 30柱纯化后进行生物学性质检测。结果 纯化后的蛋白产物纯度达 98％，是无热源、无内毒素、无甲基营养型酵母染色体 DNA污染的，有正确的分子量、等电点、氨基末端氨基酸顺序、肽图、紫外光谱、及生物活性性质的重组蛋白。结论 纯化蛋白符合动物试验和临床试验的要求，为制备多种人表皮生长因子制剂进行动物实验和临床试验打下了基础。展开更多
Non-consistency of stress results is of ten observed during field measurements. In some cases, even the rneasurernents are made at the same location in a massive rockrnass, the results can vary widely. In order to sol...Non-consistency of stress results is of ten observed during field measurements. In some cases, even the rneasurernents are made at the same location in a massive rockrnass, the results can vary widely. In order to solve the problem, extensive research has been carried out to study the major factors wh1ch rnay affect stress deterrnlnation. They include the rock behaviour and the stress state. For rocks showing non-isotropic behaviour, the values of Young’s modulus and Poisson ratio vary with the orientation of loading and measurement. Stress condition in the rock affects the rock behaviour. Furtherrnore, the loading condition on rock samples durlng laboratory tests is different from in the field and therefore the determined e1astic constants may not represent the field condi tion. In general , the Young’s modulus may depend on the orientation, the loading path, the stress magnitude and the stress ratio. This paper examines in detail the effects of those factors, especially for rocks showing transversely isotropic behaviour. It is found that the discrepancy of stress results from field measurernents in this type of rock is mainly due to over simplification of the rock behavior and inadequate use of elastic constants of the rock during stress calculation. A case study is given,which indicates the significance of these factors and demonstrates the proper procedure for stress calculation from measurements.展开更多
This study makes a qualitative inquiry into the use of collaborative learning in Chinese higher education （HE） EFL classrooms with its focus on students＇ experience. It seeks to reveal the dilemmas encountered by c...This study makes a qualitative inquiry into the use of collaborative learning in Chinese higher education （HE） EFL classrooms with its focus on students＇ experience. It seeks to reveal the dilemmas encountered by considering the cultural aspect of teaching and learning within the Chinese context. Drawing on data sources from 60 students＇ written reflections, 2 groups of post-hoc interviews and the researcher＇s field notes, the study reveals that： 1） the use of collaborative learning conflicts with students＇ formed learning behaviors and grammar- oriented exams; 2） guanxi as an indigenous Chinese sociocultural construct prevails in the language classrooms as a communicative tie among students, which facilitates students＇ interaction and peer collaboration; 3） power differentials, by contrast, engender less interaction and create distance among peers. Notwithstanding these incompatibilities, the study claims that collaborative learning is consonant with the Chinese culture that emphasizes collective orientation and socially appropriate behaviors during interaction. It is concerned with the right way of learning among peers. Finally, the study suggests ways for teacher educators to cope with these dilemmas.展开更多
文摘Non-consistency of stress results is of ten observed during field measurements. In some cases, even the rneasurernents are made at the same location in a massive rockrnass, the results can vary widely. In order to solve the problem, extensive research has been carried out to study the major factors wh1ch rnay affect stress deterrnlnation. They include the rock behaviour and the stress state. For rocks showing non-isotropic behaviour, the values of Young’s modulus and Poisson ratio vary with the orientation of loading and measurement. Stress condition in the rock affects the rock behaviour. Furtherrnore, the loading condition on rock samples durlng laboratory tests is different from in the field and therefore the determined e1astic constants may not represent the field condi tion. In general , the Young’s modulus may depend on the orientation, the loading path, the stress magnitude and the stress ratio. This paper examines in detail the effects of those factors, especially for rocks showing transversely isotropic behaviour. It is found that the discrepancy of stress results from field measurernents in this type of rock is mainly due to over simplification of the rock behavior and inadequate use of elastic constants of the rock during stress calculation. A case study is given,which indicates the significance of these factors and demonstrates the proper procedure for stress calculation from measurements.
基金supported by the Research Fund of Xi’an International Studies University(Grant No.14XWC03)Teaching Reform Project of Xi’an International Studies University(Grant No.15BYG04)~~
文摘This study makes a qualitative inquiry into the use of collaborative learning in Chinese higher education （HE） EFL classrooms with its focus on students＇ experience. It seeks to reveal the dilemmas encountered by considering the cultural aspect of teaching and learning within the Chinese context. Drawing on data sources from 60 students＇ written reflections, 2 groups of post-hoc interviews and the researcher＇s field notes, the study reveals that： 1） the use of collaborative learning conflicts with students＇ formed learning behaviors and grammar- oriented exams; 2） guanxi as an indigenous Chinese sociocultural construct prevails in the language classrooms as a communicative tie among students, which facilitates students＇ interaction and peer collaboration; 3） power differentials, by contrast, engender less interaction and create distance among peers. Notwithstanding these incompatibilities, the study claims that collaborative learning is consonant with the Chinese culture that emphasizes collective orientation and socially appropriate behaviors during interaction. It is concerned with the right way of learning among peers. Finally, the study suggests ways for teacher educators to cope with these dilemmas.
