核酸四碱基体及四螺旋模型的理论构建     

邵丹  谢君  刘世熙  刘次全 《玉溪师范学院学报》2002,18(3):64-71

核酸的结构具有多态性 ,核酸的功能取决于其结构 .了解核酸不同结构的特征有利于对其功能的充分认识 .本文对核酸四碱基体及其形成的四链结构模型进行了理论研究 .这些工作有助于从理论上进一步研究核酸四螺旋结构 ,对相关的实验研究也将起到有益参考作用 .  相似文献   

Comparison of oil and egg tempera paint systems using time-of-flight secondary ion mass spectrometry     

Zachary E. Voras  Kristin deGhetaldi  Brian Baade  Eric Gordon  Glenn Gates  Thomas P. Beebe 《文物保护研究》2016,61(4):222-235

Time-of-flight secondary ion mass spectrometry (ToF-SIMS) is quickly becoming a critical tool in the field of art conservation. This technique provides high-resolution spatial maps of both inorganic and organic components located within cross-sectional samples collected from works of art. With recent advances in surface analysis, ToF-SIMS can now be used to identify specific amino acids present in protein-containing materials as well as fatty acids in drying oils. For example, the detection of the ion fragment associated with the amino acid hydroxyproline can be used to confirm the use of animal glue in a paint sample. As an analytical technique, ToF-SIMS avoids the need for derivatization/silylation reagents, with no interference by the presence of pigments. Furthermore, the layered systems that are often encountered in historical paint samples remain intact throughout the analytical procedure. This allows for the co-localization of organic and inorganic species in specific layers (e.g. egg yolk paint atop a glue ground). Because of this ability to localize the analytical signal to approximately 6?µm or less, the mass spectral information can be used to produce mass-resolved and spatially-resolve images which can be correlated to previous studies of the same samples. In this study, ToF-SIMS was used to analyze a paint cross section obtained from a painting attributed to Raphael, and another from a painting by the Sienese artist Matteo di Giovanni.  相似文献   

鬼针草的研究现状与应用前景   总被引：8，自引：0，他引：8  

张延昌  张永明 《山东教育学院学报》2004,19(4):79-83

针对近年来对鬼针草属植物研究的资料 ,系统总结了鬼针草药用成分分析 (细胞学、生药学、化学成分、药理学 )和品种的鉴定方法 ,同时对鬼针草资源进一步开发利用指出了更广阔的前景。  相似文献   

刺五加茎叶化学成分分析   总被引：1，自引：0，他引：1  

李筱玲  邓寒霜 《商洛学院学报》2006,20(1):103-105

采用多种试剂及仪器,分析刺五加叶中氨基酸、无机元素、总糖、黄酮的含量.结果测定出了刺五加中氨基酸、无机元素、总糖、黄酮的含量,为刺五加质量控制新模式提供了参考.  相似文献   

支链氨基酸对运动能力影响的研究进展     

路正社  熊正英 《和田师范专科学校学报》2005,25(5):1-2

尽管支链氨基酸在运动过程中提供的能量很少,但它却与运动能力有密切的关系.本文从体内支链氨基酸的代谢途径;运动对支链氨基酸代谢的影响;以及补充支链氨基酸提高运动能力的机理等方面综述了支链氨基酸与运动能力关系的研究进展.  相似文献   

动脉粥样硬化性脑梗塞和脑出血患者血浆可溶性血栓调节蛋白水平的研究   总被引：1，自引：0，他引：1  

刘建仁  章昀  张敏  张佩利  黄鉴政  魏尔清 《科技通报》2003,19(2):158-161

目的 探讨血浆可溶性血栓调节蛋白（Soluble thrombmodulin,sTM）与脑梗塞和脑出血患者小血管损伤、动脉粥样硬化的关系。方法 应用酶联免疫吸附方法（Enzyme-Linked Immunosorbent Assays,ELISA），检测60例脑梗塞患者、56例脑出血患者和64例健康对照的sTM水平，并分析sTM与血脂、血压的关系。结果 脑梗塞和脑出血的甘油三脂、舒张期血压明显高于对照组；脑梗塞和脑出血的高密度脂蛋白显著低于对照组；脑出血组的收缩期血压明显高于其他两组；脑梗塞的 胆固醇水平显著高于其他两组；脑出血的sTM显著高于脑梗塞和对照组，而脑梗塞的sTM显著高于对照组。sTM与总胆固醇、甘油三脂、收缩和舒张期血压水平显著正相关；sTM与高密度脂蛋白水平成显著负相关。结论 脑梗塞和脑出血存在由高血压和动脉粥样硬化导致的小血管损伤。sTM是脑卒中的独立危险因子。  相似文献   

细菌肽聚糖及其应用     

陈国胜  谷欣  张想竹 《安阳工学院学报》2007,(6):36-38

肽聚糖是构成细菌细胞壁基本骨架的主要成分,结构具有多样性的特点.青霉素等药物能抑制肽聚糖的生物合成.细菌肽聚糖分子中肽尾第三位氨基酸的种类、肽桥的结构以及邻近肽尾交联的位置,常被用作现代微生物分类鉴定中的重要依据,肽聚糖是免疫系统的免疫增强剂,能用于疾病的诊治研究.把肽聚糖用于水产养殖等方面有利于解决生物抗药性问题及食品的药物残留问题.  相似文献   

中成药可溶性汞形态分析方法及样品结果测定     

徐陆正  解清  闫赖赖  陈玉红  王京宇 《实验技术与管理》2011,28(12):40-43

建立了微波辅助提取、HPLC-ICP-MS联用分析中成药中二价汞和甲基汞的方法。分别比较了提取液中盐酸和L-半胱氨酸含量、提取温度和提取时间对提取结果的影响,得到了微波辅助提取的最优条件:体积分数为1%的盐酸10mL和质量分数为5%的L-半胱氨酸1mL作为提取液,控温70℃,微波辅助提取1h。该方法测得的二价汞和甲基汞的精密度分别为1.7%和4.4%,加标回收率分别为80.7%～99.5%和93.7%～95.8%。并应用该方法分析测定了20种、共49批次的含朱砂的中成药中可溶性汞的形态。  相似文献   

急性力竭运动对大鼠血浆支链氨基酸及氨量变影响的研究     

钟兴明  姚鸿恩  韩慧婉 《首都体育学院学报》1999,(2)

本研究选用９ 只健康成年 Ｓ Ｄ 雄性大白鼠,采用一次性力竭游泳运动方式,通过运动前及运动后即刻从心脏取血, 测定其力竭运动前后血浆尿素氮、支链氨基酸、氨的量变情况。结果表明急性力竭性运动后大鼠血浆尿素氮、支链氨基酸、氨含量均呈明显增高, 且前两者的变化差异有显著意义（ Ｐ＜ ０． ０５）。结果提示急性力竭运动后体内蛋白质分解代谢、支链氨基酸的代谢增强,血浆氨、支链氨基酸的含量变化与运动性疲劳的出现和疲劳程度有密切关系。  相似文献   

The effect of l-citrulline and watermelon juice supplementation on anaerobic and aerobic exercise performance     

Paul T. Cutrufello  Stephen J. Gadomski  Gerald S. Zavorsky 《Journal of sports sciences》2015,33(14):1459-1466

Citrulline has been proposed as an ergogenic aid, leading to an interest in watermelon given its high citrulline concentration. The aim of this study was to determine the effects of a single, pre-exercise dose of l-citrulline, watermelon juice, or a placebo on the total maximum number of repetitions completed over 5 sets, time to exhaustion, maximal oxygen consumption (VO₂max), anaerobic threshold, and flow-mediated vasodilation. A randomised double-blind within-participants study design was used to examine these effects among 22 participants (n = 11 males). Supplementation included either a 7.5% sucrose drink containing 6 g of l-citrulline, 710 mL of watermelon juice (~1.0 g citrulline), or a 7.5% sucrose placebo drink. Supplementation was administered 1 or 2 h before exercise testing to investigate a timing effect. There was no significant effect between the three supplements for the total number of repetitions, time to exhaustion, VO₂max, anaerobic threshold, or flow-mediated vasodilation. There was also no interaction observed relative to gender or supplement timing (P > 0.05). A single dose of l-citrulline or watermelon juice as a pre-exercise supplement appears to be ineffective in improving exercise performance; however, greater doses of l-citrulline have been shown to be safe and are currently left unexamined.  相似文献