检索结果-南通市图书馆

Secondary metabolites of rice sheath blight pathogen Rhizoctonia solani Kühn and their biological activities

在线全文

学校读者我要写书评

暂无评论

Journal of Integrative Agriculture 2015年第1期14卷 80-87页

作者： XU Liang wang xiao-han LUO Rui-ya LU Shi-qiong GUO Ze-jian wang Ming-an LIU Yang ZHOU Li-gang Key Laboratory of Plant Pathology Ministry of Agriculture/Department of Plant PathologyCollege of Agronomy and BiotechnologyChina Agricultural University Institute of Agro-Products Processing and Technology Chinese Academy of Agricultural Sciences

Eight compounds were isolated from the fermentation cultures of rice sheath blight pathogen Rhizoctonia solani Kuhn. They were identified as ergosterol （1）, 6β-hydroxysitostenone （2）, sitostenone （3）, m-hydroxyphenylacetic acid （4）, methyl m-hydroxyphenylacetate （5）, m-hydroxymethylphenyl pentanoate （6）, （Z）-3-methylpent-2-en-1,5-dioic acid （7） and 3-methoxyfuran-2-carboxylic acid （8） by means of physicochemical and spectroscopic analysis. Among them, 2, 3, 5-8 were isolated from R. solani for the first time. All the compounds were evaluated for their biological activities. 4-6 and 8 showed their inhibitory activities on the radical and germ elongation of rice seeds. 1,4 and 7 showed moderate antibacterial activity to some bacteria. 4, 7 and 8 exhibited weak inhibitory activities on spore germination of Magnaporthe oryzae. 8 showed moderate antioxidant activity with the 1,1-diphenyl-2-picryhydrazyl （DPPH） andβ-carotene-linoleic acid assays. This is the first time to reveal compounds 5, 6 and 8 from rice sheath blight pathogen R. solani to have in vitro phytotoxic activity.

关键词： rice sheath blight Rhizoctonia solani Kuhn secondary metabolites bioactivities in vitro phytotoxic activity

Evaluation of Sensitivities and Specificities of SARS-CoV Detection by Real-time Quantitative Reverse Transcription-PCR Assays

在线全文

学校读者我要写书评

暂无评论

Virologica Sinica 2009年第3期24卷 187-193页

作者： Li-li XU Zhi-hong HU Hua-lin wang xiao han Fei DENG State Key Laboratory of Virology Wuhan Institute of Virology Chinese Academy of Sciences Wuhan 430071 China

The etiological agent of severe acute respiratory syndrome(SARS) was identified as a new coronavirus,termed SARS-CoV. Establishment of an efficient and sensitive diagnostic system of SARS-CoV genetic materials is crucial for SARS control. In this study,we quantified SARS-CoV mRNAs in both infected cell culture lysate and in supernatant by using Real-time quantitative revere transcription-PCR based on EvaGreenTM dye and Taqman-MGB probes. For extensive evaluation of sensitivities and specificities,13 pairs of primers and 4 probes were designed based on different genes of SARS-CoV. Glyceraldehydes-3-phosphate dehydrogenase(GAPDH) was selected as the internal control gene. Results showed that S-gene-specific PCR was the most sensitive for detection,but because of its sequence variability in the different viral strains,primers and a probe based on the N gene were suitable substitutions. Meanwhile,we found the mRNA concentrations in cell culture lysates were much higher than in cell supernatant and facilited more sensitive detection of the SARS-CoV.

关键词： SARS-CoV Sensitivities Specificities Evaluation

Impacts of land cover change on plant and bird species diversity in Hainan Island,China

在线全文

学校读者我要写书评

暂无评论

Journal of Environmental Sciences 1999年第2期11卷 100-103页

作者： Ouyang Zhi yun, wang Ru song, wang xiao ke, xiao han Research Center for Eco Environmental Sciences,Chinese Academy of Sciences,Beijing 100085, China

Hainan Island, located at the southern end of China, has less than 0.4% of land area but contains 13% of plant and animal species in China. During the last four decades many primary forests have been converted to shrub land, grassland, and tree planation (e.g., eucalyptus forest). As a result, area of primary tropical forest has been reduced from 25.8% in the 1950s to 4% in the 1990s. To assess impacts of land conversion on plant and bird species diversity, a series of samples in primary forest and four types of converted lands were took. The land conversion had tremendously reduced both plant and bird species diversity. Specifically, plant species richness per site was 83.7 in primary forest, 28.3 in shrub land, 12.5 in grassland, 14.4 in eucalyptus forest, and 21.4 in Acacia forest. Bird species richness showed a similar trend: 22.0 in primary forest, 14.5 in shrub land, 2.5 in grassland, 4.9 in eucalyptus forest, and 9.0 in Acacia forest. The Shannon species diversity indices for plants in the five types of land cover were 3.69, 1.99, 0.97, 1.47 and 2.07, respectively. Similarly, the Shannon indices for bird species diversity were the highest in primary forest, and lowest in grassland, and intermediate in shrub land and eucalyptus forest.

关键词： land cover change species diversity Hainan Island.

SYNTHESIS AND CHARACTERIZATION OF NEW LIQUID CRYSTALLINE POLYUREThanE

在线全文

学校读者我要写书评

暂无评论

Chinese Chemical Letters 1993年第4期4卷 311-312页

作者： De Li wang xiao Zu han Da Wei CAI Lian Ying xiao xiao Fu XUE Zhi Shen MO Changchun Institute of Applied Chemistry,Academia Sinica,Changchun 130022

A new Schiff base diol,4,4'-[3-methoxy-4-(2-hydroxy)-ethoxy]azomethine biphenyl(MHAMB), was synthesized,which was copolynerized with PEC-600 and TDI to obtain a blook *** monomer and the polymer were charaoterized by ... 详细信息

关键词：台五 PU LC SYNTHESIS AND CHARACTERIZATION OF NEW LIQUID CRYSTALLINE POLYUREThanE Poly

Mersenne数的Smarandache函数值的下界

在线全文

学校读者我要写书评

暂无评论

西北大学学报（自然科学版） 2014年第3期44卷 367-369页

作者：王枭涵西安外国语大学经济金融学院陕西西安710127

对于正整数n,设S(n)是n的Smarandache函数。对于素数p,设Mp=2p-1是Mersenne数。文中运用初等方法讨论了S(Mp)的下界。证明了:对于任何正整数x,如果p≥9x2(logx+1)3,则必有S(Mp)≥2xp+1。

关键词： Mersenne数 Smarandache函数下界

主动冷却通道内正庚烷热裂解与换热过程的数值模拟

在线全文

学校读者我要写书评

暂无评论

推进技术 2018年第4期39卷 827-834页

作者：李浩瀚吴勇于会宾汪小憨中国科学院广州能源研究所广东广州510640 中国科学院可再生能源重点实验室广东广州510640 广东省新能源和可再生能源研究开发与应用重点实验室广东广州510640 中国科学院大学北京100049

为了深入研究碳氢燃料在主动冷却通道中的传热特性,采用详细基元反应机理对微小通道内正庚烷热解反应耦合流动换热过程进行了数值模拟。根据燃料的热裂解反应和壁面传热特性可将通道分为三个换热区域。通过对不同的入口温度、运行压力... 详细信息

为了深入研究碳氢燃料在主动冷却通道中的传热特性,采用详细基元反应机理对微小通道内正庚烷热解反应耦合流动换热过程进行了数值模拟。根据燃料的热裂解反应和壁面传热特性可将通道分为三个换热区域。通过对不同的入口温度、运行压力、壁面温度和通道直径等典型工况进行模拟,探索了正庚烷的热裂解反应和流动换热过程耦合的基本规律。研究结果表明,入口温度对通道整体的换热性能影响不大;保持其它参数不变,通道直径从2mm减小到0.5mm,其整体换热量降低约10%,单位面积的换热量提升约4倍。

关键词：热裂解详细反应动力学微小通道正庚烷数值模拟

在线全文

学校读者我要写书评

暂无评论

论我国弱势群体权利保障制度之完善

烟台大学学报（哲学社会科学版） 2017年第5期30卷 104-113页

作者：王笑寒北京大学人口研究所北京100871

弱势群体的权利保障问题,涉及社会公平正义价值观的实现,在任何国家都是一个值得重视的问题。在这方面,随着改革开放的进程,我国已取得了巨大的成绩。但从制度等深层次审视,我国弱势群体权利保障方面还存在诸多问题。这些问题,既涉及国... 详细信息

弱势群体的权利保障问题,涉及社会公平正义价值观的实现,在任何国家都是一个值得重视的问题。在这方面,随着改革开放的进程,我国已取得了巨大的成绩。但从制度等深层次审视,我国弱势群体权利保障方面还存在诸多问题。这些问题,既涉及国家在法律、政策及社会体系方面的顶层设计,又涉及弱势群体法定权利的确定、实现以及救济等具体制度的完善与改革。保障弱势群体的正当合法权益,我们还有很长一段路要走。应制定一部保障弱势群体权益的基本法,确定弱势群体保障制度的基本原则,形成以平等权、生存权、发展权为核心的人权标准体系,确保弱势群体既有利益表达渠道通畅,同时开拓新的利益表达机制,使该群体的利益和尊严能在不久的将来获得更为充分的保护。

关键词：弱势群体权利保障制度设计与解决方案