蒲公英提取物黄酮类物质成分及其抗氧化活性的初步研究

蒲公英全草干粉经乙醇回流提取,聚酰胺柱层析（poyamide pole)得到的黄酮类提取物（total flavonoid)的纯度为67．4％,用高效液相色谱法（HPLC）测定其中的芦丁（Rutin)占5．49％,槲皮素占1．22％,另外还有其他黄酮类物质,经NBT法测定的结果表明,萍公英黄酮类提取物和其中的芦丁均有较强的体清全超氧阴离子(O^－2）的能力。     

黄酮类物质在豆科植物结瘤固氮中的作用

介绍黄酮类物质对根瘤菌的趋化、结瘤基因的诱导、根瘤菌的生长、根瘤的发育和固氮的作用,以及黄酮类物质在豆科植物中的分布和分泌。     

概念图在医学微生物学教学中的应用

概念图已成为各种教育背景下的学习工具,通过概念图可以构建学生的知识结构、促进学生批判性思维的发展和对知识的理解。本文初步探讨了概念图在医学微生物学教学准备、教学实施及教学评价等方面的有效应用。     

香薷叶表皮腺毛及其分泌黄酮类物质的组织化学研究

利用光学显微技术和扫描电镜技术,研究了香薷营养生长期和生殖生长期的枝条上部、中部、下部叶片的腺毛种类、分布及数量;采用组织化学染色和荧光显微技术,观察香薷腺毛分泌黄酮类物质的过程,探讨香薷叶表皮腺毛的泌香机理,为生产中确定提取香薷黄酮类物质的最佳取材时期提供依据。结果表明:(1)香薷叶表皮有头状腺毛和盾状腺毛,成熟的头状腺毛包括基细胞、柄细胞和头部,头部较小,呈半圆球型,直径为(20±2)μm;发育近成熟的盾状腺毛头部较大,呈盾状,直径为(60±5)μm。(2)香薷叶片远轴面和近轴面均有腺毛的分布,远轴面分布较多,近轴面分布较少;盾状腺毛主要分布在叶的远轴面,头状腺毛在叶的两面均有分布;腺毛密度随节位的降低而减少,节位相同时,营养生长期叶片上的腺毛密度(283.9个/mm2)高于生殖生长期(194.4个/mm2)。(3)香薷头状腺毛和盾状腺毛均能分泌黄酮类物质,且随着腺毛的发育成熟,黄酮类物质逐渐积累于腺毛的头部。     

概念图在植物学复习教学中的运用

应用“概念图”组织复习绿色开花植物的根、茎、叶、花、种子、果实六大器官的结构功能及其生长发育过程,复习绿色开花植物光合作用、呼吸作用、吸收作用、蒸腾作用、运输作用5种生活方式,构建概念图促使学生整合新旧知识,浓缩知识结构,建构知识网络,提高学生从整体上把握知识的能力。     

胜红蓟黄酮类物质对柑桔园主要病原菌的抑制作用

柑桔园引种杂草胜红蓟能有效地控制主要病害,研究发现,胜红蓟产生并释放到土壤中的黄桐类物质对疮痂病菌、炭疽病菌、白粉病菌和烟煤病菌等柑桔园主要病原真菌具有抑制活性,从胜红蓟植株中分离鉴定了10个黄酮物质,包括一个糖甙黄酮分子,但胜红蓟植株产生的大部分黄酮物质在土壤中会逐渐降解,只有3个黄酮分子能在柑梧园的土壤中累积并存在较长时间,而这3个黄酮物质对柑桔园主要病原真菌具有显著的抑制活性,其活性不仅超过胜红蓟释放的其化感物质,而且强于商业的杀菌剂多菌灵,表明胜红蓟产生和释放的黄酮物质在柑桔园病害控制中起着重要作用。     

十二烷基硫酸钠辅助提取布渣叶中的黄酮类物质

以布渣叶为研究体系,采用表面活性剂辅助热回流法提取黄酮类物质.考察了表面活性剂种类及浓度、提取时间、液固比和溶剂pH等因素,并通过实验数据进行了正交试验设计,得到最优的工艺条件:表面活性剂选择十二烷基硫酸钠(SDS),质量浓度0.8 g/L,提取时间105 min,液固比45 mL/g,溶剂pH 6.3.在此条件下,布渣叶黄酮得率为15.73％,与其他方法相比具有显著优势.     

电子概念图在医学微生物学教学中的应用

研究电子概念图对提高医学微生物学教学效果的作用。设计实验组和对照组, 实验组完成电子概念图练习, 填写问卷表, 与对照组一起参加闭卷考试; 用社会科学统计软件包 (Solutions statistical package for the social sciences, SPSS) 分析闭卷考成绩, 讨论、评价问卷答案。在练习过程中, 教师制作概念图脚手架, 学生完成作业后, 教师再提供反馈意见。两组闭卷考试总分和名词解释等得分有明显差异; 调查问卷提示, 实验组多数学生认为电子概念图有利于提高理解记忆力。概念图反映大脑的思考过程, 展示发散性思维。概念图可提高实验组学生的《医学微生物学》成绩, 是医学教学的有力助手。     

概念图及其在教与学中的应用

1 关于概念图的概述概念 图是一种关于概念知识、思维过程或思维结果、系统结构、计划流程等的图形化表征方式，它由节点、链接（节点间的连线）和节点间的关联词组成。康奈尔大学的Joseph D．Novak博士根据奥苏贝尔（David P．Ausubel）学习理论于1960年始研究概念图技术，并使之成为一种教学工具。学生利用概念图进行知识的自主建构，教师利用概念图引导和考察学生组织知识、理解知识的过程，都与建构主义学习观是一致的。     

概念图策略在生理学教学实践中的应用

目的:探讨概念图策略在高职护理专业生理学教学实践中的效果。方法:随机抽取57名学生作为实验组,54名学生作为对照组;实验组施行概念图策略教学法,对照组则采用传统教学法。分别比较两组学生的单元测验成绩和期末考试成绩,并于全部课程结束后进行问卷调查,分析调查结果。结果:实验组学生的单元测试成绩和期末考试成绩均明显高于对照组学生,差异具有统计学意义(P<0.05);实验组94.34%的学生认为教学能够提高学习主动性,而对照组为64.81%;实验组84.21%的学生认为教学有助于提升对课程内容的理解,而对照组为64.11%;实验组87.72%的学生认为教学促进师生互动,而对照组为38.89%;实验组84.21%的学生认为教学可增强团队合作精神,而对照组为57.41%。实验组的调查结果明显优于对照组,差异具有统计学意义(P<0.05)。结论:将概念图策略引入高职护理专业的生理学课程教学实践中,能够更好的帮助学生掌握生理学的理论体系,提升教学质量,提高学生的专业知识水平。     

Effects of organic pH buffers on a cell growth and an antibody production of human-human hybridoma HB4C5 cells in a serum-free culture

Human-human hybridoma cells secreting a human monoclonal antibody were cultured in a serum-free medium containing various organic pH buffers in order to clarify their effects on cell growth and antibody production. Organic pH buffers having either one sulfonic acid and several acyclic amine moieties, or several cyclic amine moieties containing two amino nitrogen did not inhibit cell growth; while other organic buffers sulfonic acid moiety plus several cyclic amine moieties containing one amino nitrogen slightly decreased cell growth, but enhanced antibody production. Using Fujita's organic conceptual diagram, a relationship between the organicity and inorganicity of a pH buffer to cell growth and antibody production was found. pH buffers with large inorganicity and small organicity values were favorable for cell growth, and buffers with small inorganicity and large organicity values were preferred to enhance antibody production. Although the pH buffering range affects cell growth, its effect on antibody production is not clear. In conclusion, 2-morpholinoethanesulfonic acid (MES), 3-morpholino-propanesulfonic acid (MOPS) and 1, 2-N, N-bis[N, N-di(2-sulfonoethyl)piperazinyl]ethane (Bis-PIPES) are shown to be the most optimal of the buffers tested, because they enhanced antibody production without decreasing the cell growth among the pH buffers tested here.     

Reliability Analysis of the Groundwater Conceptual Model

The hydrologic model is the foundation of water resource management and planning. Conceptual model is the essential component of groundwater model. Due to limited understanding of natural hydrogeological conditions, the conceptual model is always constructed incompletely. Therefore, the uncertainty in the model's output is evitable when natural groundwater field is simulated by a single groundwater model. A synthetic groundwater model is built and regarded as the true model, and three alternative conceptual models are constructed by considering incomplete hydrogeological conditions. The outputs (groundwater budget terms from boundary conditions) of these groundwater models are analyzed statistically. The results show that when the conceptual model is closer to the true hydrogeological conditions, the distributions of outputs of the groundwater model are more concentrated on the true outputs. Therefore, the more reliable the structure of the conceptual model is, the more reliable the output of the groundwater model is. Moreover, the uncertainty caused by the conceptual model cannot be compensated by parameter uncertainty.     

有机框架材料在多肽富集的应用

生物医药领域近年来发展迅猛,多肽类药物因其生物学活性高、毒性小、生物相容性好等优势,在肿瘤治疗、细胞活性模拟、抗体检测等领域展开广泛应用,多肽的检测分析也成为研究的一大热点。传统的色谱法、溶剂沉淀法、离心超滤法和固相萃取法对多肽能够展现富集效果,但富集的效率往往不够理想。近年来,以有机框架材料为代表的纳米材料,在气体吸附、荧光、传感和催化等领域展开了广泛应用。有机框架材料凭借着独特的结构尺寸,成为了一类理想的生物吸附剂。由于其具有表面可修饰性,能够大大提高对多肽的富集效率。本文着重介绍近5年来金属-有机框架材料（metalorganic frameworks,MOFs）和共价-有机框架（covalent-organic frameworks,COFs）在多肽富集中的应用。     

Conceptual and ethical problems in the epistemology of genetic information

My thesis will be that the identification of genetic features and their medical interpretation follow at least partially from reductionist premises: “Genes are charging the gun, life(-style) will trigger it.” This simplistic metaphor illustrates a problem of genetic diagnosis: from the viewpoint of philosophy of science, concepts of the gene and the genome are vague and confused. Until now these concepts have not been defined satisfactorily. Partly on account of this there is an additional problem in applying genetic tests in medical diagnostics. The epistemic status of predictive genetic diagnosis in many cases can justifiably be called “opaque.” But a predictive genetic test is designed to reveal genetic knowledge of and for a client on the basis of scientific research. Methodologically the diagnosis of the scientific problem in genetics as a science is developed philosophically as an epistemological argument. The problem of genetics as applied science in medicine and society is the danger of irrationality due to reductionist premises of science. This problem is to be revealed by philosophical analysis. The major result of the argument is that the assessment of applications of basic research in genetics should include considerations from epistemology and philosophy of science. The epistemological status of scientific concepts and reasonableness of advice are interrelated. My thesis is that at the interface between theory of science in genetics and reasonableness of “genetic advice” is the responsibility of the researchers for concepts of their science.     

Conceptual Site Models and Multimedia Modeling: Comparing MEPAS,MMSOILS, and RESRAD

The use of multimedia models to assess current and future human and ecological exposure to contamination at hazardous waste sites has become common practice in recent years. The U.S. Environmental Protection Agency has identified development of a conceptual site model as a critical part of the risk assessment process. This paper investigates the relationship between the choice of conceptual site models and application of multimedia models and the variation in risk estimates obtained when using data and default parameter values suggested by the individual model developers.     

Developing Conceptual Categories in Classroom Descriptive Research: Some Problems and Possibilities

This article reflects on a classroom study of children's literary responses to unpack the process of building conceptual categories in ethnographic research, thus challenging accounts that obscure the role of the researcher and present findings as fixed and infallible.     

Conceptual model of seagrass die-off in Florida Bay: Links to biogeochemical processes

Seagrasses are recognized as important plant communities in coastal estuaries and lagoons across both tropical and temperate climes; thus, large-scale seagrass die-off events worldwide are of general concern. In Florida Bay, at the southern terminus of the Florida peninsula, seagrass die-off events up to 4000 ha have been reported and smaller scale mortality events are noted annually. In the present study, we examined several hypothesized causative factors (high temperature, hypersalinity, sulfide toxicity) of seagrass (Thalassia testudinum) mortality in Florida Bay. To test sulfide effects, in situ sulfide production was stimulated by applying a labile carbon source (glucose) to sulfate reducers in the sediment at five sites across the bay (northeastern, northcentral, and southwestern basins). During the one year study, high temperature (32–36 °C) and salinity (> 50 psu) were recorded in the bay associated with a regional drought. We also experienced major seagrass die-off events at two of our southwestern bay sites. These field conditions provided an excellent opportunity to closely examine cause–effect relationships among stressors and die-off events in the field, and verify results of our previous mesocosm experiments. Even though glucose amendments stimulated porewater sulfides in bay sediments (4–8 mmol L^− 1), no significant differences in biomass, short shoot density or final growth rates were found between control and glucose plots. In addition, the highest growth rates and shoot densities were concomitant with maximum water column salinity (> 50 psu) and temperature (32–36 °C), when porewater sulfides were also in the millimolar range. Large-scale seagrass mortality events, encompassing  50% of the entire meadow at one site, occurred at southwestern bay sites when plants were down regulating (slower growth and shoot density), probably in response to shorter day length and lower temperature (30–34 to 23–26 °C) from October, 2004 to January, 2005. Sulfate reduction rates (SRR) were also 2-fold higher in the southwestern (214–488 nmol cm^− 3 d^− 1) versus northcentral and northeastern (97–240 nmol cm^− 3 d^− 1) bay sites, possibly limited by labile carbon, which we found to stimulate SRR 3-fold in northeastern and northcentral bay sites (461–708 nmol cm^− 3 d^− 1) and 4-fold at southwestern bay sites (1211–2036 nmol cm^− 3 d^− 1). Based on a synthesis of the field data reported herein, our mesocosm experiments to date, and contributions by others, we present a conceptual model of seagrass die-off in Florida Bay outlining a cascade of stressors, stimulated by P enrichment, which leads to high O₂ consumption in the system triggering a seagrass die-off event.     

土壤有机质和外源有机物对甲烷产生的影响

对土壤有机质含量及组分、外源有机物和根系分泌对甲烷产生的影响作了综述。土壤产甲烷量和甲烷排放量随有机质含量增加而提高,与土壤中易矿化有机碳或沸水浸提有机碳含量呈显著相关。外源有机碳加入促进了土壤排放甲,刺激效果与外源有机碳的用量和组成有关。还原力强的有机物如纤维素和半纤维素较还原力弱的有机物如类脂和多糖能够产生更多的甲烷。甲醇、甲基化氨基酸等无其它微生物竞争利用的有机物能被产甲烷菌更多地转化成甲烷。植物根系分泌物也促进甲烷的产生,促进作用大小与植物种类及分泌物的数量和质量有关。外源有机物通过3种方式促进土壤甲烷产生;提高土壤的甲烷底物供应量,降低土壤氧化还原电位,刺激土壤原有有机碳的转化。     

连钱草中有机酸成分研究

从连钱草（Glechoma longituba）分离并鉴定了5个有机酸化合物,分别为：月桂酸（1）、二十四烷酸（2）、丁二酸（3）、顺丁烯二酸（4）、三十烷酸（5）。化合物1-5均是首次从该属植物中分离得。