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禾豆间作氮素高效利用机理及农艺调控途径研究进展 被引量:54
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作者 柴强 胡发龙 陈桂平 《中国生态农业学报》 CAS CSCD 北大核心 2017年第1期19-26,共8页
为保障粮食安全,农业生产中化肥使用极为普遍,但过量使用,往往引起地下水污染、温室效应加剧、生物多样性降低等多种环境和生态问题。禾豆间作系统由于不同作物生物学特性和氮素利用存在差异,进行合理调控可充分发挥生物固氮优点,从而... 为保障粮食安全,农业生产中化肥使用极为普遍,但过量使用,往往引起地下水污染、温室效应加剧、生物多样性降低等多种环境和生态问题。禾豆间作系统由于不同作物生物学特性和氮素利用存在差异,进行合理调控可充分发挥生物固氮优点,从而减少化肥投入,提高生产效益,是一种稳产、高产、高效可持续的种植体系。该系统中"氮转移"、"氮阻遏"消减和氮素时空分异是目前研究的热点,也是促进豆科作物固氮、减少化肥投入的有效途径,可实现禾、豆两种作物对氮素的高效利用。特别是该系统中作物品种、施氮制度、空间布局以及种植密度等农艺措施是对种间关系进行调控的必要手段,合理优化可有效促进禾/豆间作竞争与互补协同作用,增强氮素协调利用,从而挖掘两种作物对氮素高效利用的生物学潜力。为此,本文基于前人研究成果和农业可持续发展观点,重点综述了国内外有关禾豆间作氮素高效利用主要机理及相关农艺调控途径的研究现状,旨在为构建简易、高产、高效、氮肥节约型禾豆间作模式提供有力的科学依据和理论支撑。 展开更多
关键词 禾豆间作 氮转移 氮阻遏 种间关系 氮素高效利用
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蛇床子素抑制膀胱癌细胞生长和侵袭的机制 被引量:9
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作者 刘军 徐冉 赵晓昆 《中南大学学报(医学版)》 CAS CSCD 北大核心 2016年第4期345-352,共8页
目的:探讨蛇床子素对表皮生长因子受体酪氨酸激酶(epidermal growth factor receptor tyrosine kinase,EGFRTPK)、基质金属蛋白酶(matrix-metalloproteinase-2,MMP-2)和氨肽酶N(aminopeptidase N,APN)的抑制作用,并阐明蛇床子素抑制膀胱... 目的:探讨蛇床子素对表皮生长因子受体酪氨酸激酶(epidermal growth factor receptor tyrosine kinase,EGFRTPK)、基质金属蛋白酶(matrix-metalloproteinase-2,MMP-2)和氨肽酶N(aminopeptidase N,APN)的抑制作用,并阐明蛇床子素抑制膀胱癌T24细胞生长和侵袭的机制。方法:利用分光光度法研究蛇床子素对T24细胞EGFR-TPK,APN,MMP-2和caspase-3活性的影响,利用MTT法测定蛇床子素对膀胱癌T24细胞和人正常膀胱上皮细胞SV-HUC-1生长的抑制作用,采用Transwell小室法分析蛇床子素对膀胱癌T24细胞转移能力;Western印迹检测培养液中加入蛇床子素后,人膀胱癌细胞株T24中COX-2,VEGF及β-actin的表达;采用非放射性NF-κB凝胶迁移或电泳迁移率实验(electrophoretic mobility shift assay,EMSA)试剂盒测定T24细胞中NF-κB活性。结果:蛇床子素对EGFR-TPK,APN和MMP-2的半数抑制浓度(IC_(50))分别为(45.33±3.98),(28.21±3.23)和(8.11±0.54)μmol/L;随着蛇床子素浓度的增加,膀胱癌T24细胞生长抑制率不断增高,与空白对照组比较,差异均具有统计学意义(P<0.05);但SV-HUC-1细胞的生长并未受到明显的抑制;与空白对照组比较,蛇床子素组穿膜细胞的数减少(P<0.05);膀胱癌T24细胞中凋亡蛋白caspase-3活性显著增强(P<0.05);蛇床子素能够下调NF-κB,COX-2及VEGF的表达。结论:低毒性的蛇床子素可能通过降低EGFR-TPK,APN和MMP-2活性和NF-κB,COX-2及VEGF的表达,激活caspase-3活性的方式,对膀胱肿瘤细胞的侵袭、增殖和血管生成产生抑制作用。 展开更多
关键词 蛇床子素 表皮生长因子受体酪氨酸激酶 基质金属蛋白酶 氨肽酶n 膀胱癌T24细胞 抑制作用 血管生成 CASPASE-3
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Appraisal of the Production-Oriented Approach: An Introduction 被引量:4
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作者 濮实 《Chinese Journal of Applied Linguistics》 SCIE 2017年第4期452-453,共2页
The production-oriented approach (POA) has been developed over a decade. It is driven by the need to improve English classroom instruction for university students in China (Wen, 2016). It is also motivated by the ... The production-oriented approach (POA) has been developed over a decade. It is driven by the need to improve English classroom instruction for university students in China (Wen, 2016). It is also motivated by the aspiration to enhance the quality of foreign language education in other similar pedagogical contexts outside China. A volume of research has been done by Wen Qiufang and her research team, to formulate the theory of POA and to test its effectiveness in classroom pedagogy (e.g. Wen, 2016, 2015; Yang, 2015; Zhang, 2015). At the moment, the POA is still at an early stage of theory building and almost all empirical research is done in the Chinese context. In order to improve the quality of this theory and to make it intelligible to the international academic community, a one-day symposium was held in Beijing Foreign Studies University on May 15, 2017. The symposium was entitled 'The first international forum on innovative foreign language education in China: Appraisal of the POA'. In the forum, leading experts in applied linguistics were invited to discuss the strengths and weaknesses of the POA and the directions for its future development. The symposium was the first attempt for the POA research team to discuss its latest work with international scholars. This Viewpoint section collects the responses of four experts who participated in the symposium, listed in alphabetical order. The collection of articles covers three topics related to the POA: its pedagogical application, its use for teacher training, and its research. Alister Cumming is Professor Emeritus and the former Head of the Centre for Educational Research on Languages and Literacies, University of Toronto, Canada. His article focuses primarily on POA research as an exemplary case of design-based research. Rod Ellis is Research Professor in the School of Education at Curtin University, Australia. He discusses POA in terms of pedagogy, teacher training and research, with both critiques and constructive suggestions. Paul Kei Matsuda is Professor of English and Director of Second Language Writing at Arizona State University, the writed states. He responds to POA from the perspective of an expert researcher and teacher of L2 writing. Charlene Polio is Professor and Associate Chair in the Department of Linguistics & Germanic, Slavic, Asian & African Languages atMichigan State University, the writed states. She conceptualises POA as a useful method to address some issues in pre-service teacher development. Overall, the articles in this section are insightful and reader-friendly. They are not only useful for the development of POA in particular, but may also be valuable to a broad range of researchers as they touch upon pertaining issues, as well as emerging topics, in the field of applied linguistics. We therefore find it necessary to make them accessible to a wide readership. 展开更多
关键词 The production-oriented approach (POA) has been developed over a decade. It is driven by the need to improve English classroom instruction for university students in China (Wen 2016). It is also motivated by the aspiration to enhance the quality of foreign language education in other similar pedagogical contexts outside China. A volume of research has been done by Wen Qiufang and her research team to formulate the theory of POA and to test its effectiveness in classroom pedagogy (e.g. Wen 2016 2015 Yang 2015 Zhang 2015). At the moment the POA is still at an early stage of theory building and almost all empirical research is done in the Chinese context. In order to improve the quality of this theory and to make it intelligible to the international academic community a one-day symposium was held in Beijing Foreign Studies University on May 15 2017. The symposium was entitled 'The first international forum on innovative foreign language education in China: Appraisal of the POA'. In the forum leading experts in applied linguistics were invited to discuss the strengths and weaknesses of the POA and the directions for its future development. The symposium was the first attempt for the POA research team to discuss its latest work with international scholars. This Viewpoint section collects the responses of four experts who participated in the symposium listed in alphabetical order. The collection of articles covers three topics related to the POA: its pedagogical application its use for teacher training and its research. Alister Cumming is Professor Emeritus and the former Head of the Centre for Educational Research on Languages and Literacies University of Toronto Canada. His article focuses primarily on POA research as an exemplary case of design-based research. Rod Ellis is Research Professor in the School of Education at Curtin University Australia. He discusses POA in terms of pedagogy teacher training and research with both critiques and constructive suggestions. Paul Kei Matsuda is Professor of English and Director of Second Language Writing at Arizona State University the writed states. He responds to POA from the perspective of an expert researcher and teacher of L2 writing. Charlene Polio is Professor and Associate Chair in the Department of Linguistics Germanic Slavic Asian African Languages atMichigan State University the writed states. She conceptualises POA as a useful method to address some issues in pre-service teacher development. Overall the articles in this section are insightful and reader-friendly. They are not only useful for the development of POA in particular but may also be valuable to a broad range of researchers as they touch upon pertaining issues as well as emerging topics in the field of applied linguistics. We therefore find it necessary to make them accessible to a wide readership.
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榅桲籽的化学成分及其PTP1B抑制活性 被引量:7
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作者 哈及尼沙 阿卜杜热合曼.努如拉 +2 位作者 李改茹 马桂芝 程煜凤 《药学学报》 CAS CSCD 北大核心 2019年第3期510-513,共4页
采用硅胶、Sephadex LH-20及半制备液相等多种色谱方法从榅桲种子中分离得到11个化合物,利用UV、1D、2D NMR、HR-ESI-MS等波谱技术分别鉴定为5,7-二羟基-2-正二十五烷基色烯-4-酮(1)、乌苏酸(2)、委陵菜酸(3)、齐墩果酸(4)、β-胡萝卜苷... 采用硅胶、Sephadex LH-20及半制备液相等多种色谱方法从榅桲种子中分离得到11个化合物,利用UV、1D、2D NMR、HR-ESI-MS等波谱技术分别鉴定为5,7-二羟基-2-正二十五烷基色烯-4-酮(1)、乌苏酸(2)、委陵菜酸(3)、齐墩果酸(4)、β-胡萝卜苷(5)、β-谷甾醇(6)、苦杏仁苷(7)、芦丁(8)、山柰酚(9)、槲皮素(10)和异槲皮素(11)。其中化合物1为新化合物, 3和5为首次从榅桲属中分离得到,其他成分均为首次从榅桲籽中分离得到。用体外PTP1B抑制活性实验,化合物1~4和8对PTP1B有抑制活性,其IC50值分别为0.465、16.14、28.96、23.78和11.70μmol·L^(-1)。 展开更多
关键词 榅桲籽 化学成分 5 7-二羟基-2-正二十五烷基色烯-4-酮 PTP1B抑制活性
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