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Ling Tang Xiao Juan Wu Bao Min Feng Li Ying Shi Xue Yan Fu Yong Qi Wang Mei Feng Liu 《中国化学快报》2011,22(7):835-838
Two new acetylated kaempferol glycosides were isolated from the seeds of Camellia semiserrata Chi,their structures were elucidated as kaempferol-3-O-[(3-O-acetyl)-α-L-rhamnopyranosyl(1→3)(4-O-acetyl)-α-L-rhamnopyranosyl(1→6)-β-D-glucopyranoside] (1) and kaempferol-3-O-[(2-O-acetyl)-α-L-rhamnopyranosyl(1→3)(4-O-acetyl)-α-L-rhamnopyranosyl(1→6)-β-D-gluco -pyranoside](2) by spectral experiments(including ESI-MS,1D- and 2D-NMR). 相似文献
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研究了配位体和氧化改性对活性炭吸附Ag^ 及其配合物的影响以及银在活性炭表面的分布特征。结果表明:(1)活性炭对Ag^ 的吸附非常快,且不受离子强度的影响.但当Ag^ 形成[Ag(NH3)2]^ 和[Ag(S2O3)2]^3-后在活性炭上吸附性能下降,氨水浓度增加对[Ag(NH3)2]^ 的吸附没有影响,而还原性的Na2S2O3浓度增加使[Ag(S2O3)2]^3-的吸附下降。(2)银主要分布在活性炭的外表面,Ag^ 浓度和吸附时间不同将导致银颗粒的分布及粒径也不同,合理控制Ag^ 浓度和吸附时间,就可以在活性炭表面负载纳米金属银.(3)活性炭氧化改性不利于Ag^ 和[Ag(S2O3)2]^3-的吸附,却有利于[Ag(NH3)2]^ 的吸附。 相似文献
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ZHAO Wei LIANG GuiZhao CHEN YuZhen & YANG Li Key Laboratory of Biorheological Science Technology Ministry of Education Bioengineering College Chongqing University Chongqing China 《中国科学B辑(英文版)》2011,(7)
An integrated approach is proposed to predict the chromatographic retention time of oligonucleotides based on quantitative structure-retention relationships(QSRR) models.First,the primary base sequences of oligonucleotides are translated into vectors based on scores of generalized base properties(SGBP),involving physicochemical,quantum chemical,topological,spatial structural properties,etc.;thereafter,the sequence data are transformed into a uniform matrix by auto cross covariance(ACC).ACC accounts for the ... 相似文献
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提出一种新的组合方法用于β-turns预测和特征分析.该方法包括两步:如何表征β-turns特征和如何构建其预测模型.第一步应用氨基酸广义信息因子分析标度表征蛋白质中β-turns的结构特征,该标度涉及氨基酸的疏水性、α-螺旋与转角倾向、体积性质、构成特征、局部柔性及静电性.第二步以426个蛋白质为训练集样本,通过留1/7法交互验证,基于支持向量机建立β-turns预测模型.该模型分别成功地预测547和823个蛋白的β-turns.所得结果与所对比方法结果相当,更重要的是,SVM模型提供了一些关于β-turns特征的重要结构信息.该组合方法可以进一步尝试用于蛋白质结构预测及特征分析. 相似文献
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LIANG GuiZhao & ZHAO Wei Key Laboratory of Biorheological Science Technology Ministry of Education Bioengineering College Chongqing University Chongqing China 《中国科学:化学》2010,(5)
This paper offers a new combined approach to predict and characterize β-turns in proteins.The approach includes two key steps,i.e.,how to represent the features of β-turns and how to develop a predictor.The first step is to use factor analysis scales of generalized amino acid information(FASGAI),involving hydrophobicity,alpha and turn propensities,bulky properties,compositional characteristics,local flexibility and electronic properties,to represent the features of β-turns in proteins.The second step is to ... 相似文献
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低能氮离子对腺嘌呤水溶液损伤作用的光谱分析 总被引:1,自引:1,他引:0
利用气体常压弧光放电产生低能N^ 离子,在阴极位降的加速下被注入到腺嘌呤(A)水溶液中,研究了低能N^ 离子作用后腺嘌呤水溶液的紫外,红外及核磁共振光谱的变化。结果表明,低能N^ 离子的注入对溶液样品造成了多种形式的损伤,其中不仅包括N^ 直接与水作用,还包括溶液中各种碎片之间重新化合,形成丰富多采的损伤产物。 相似文献
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Several gentamicin bulk samples from different origins were investigated using an LC/MS method.LC equipped with ion trap MS with positive ionization was performed on a Capcell Pak C18(AQ) column with the mobile phase containing 50 mM trifluoroacetic(TFA) and methanol.Impurities present in batches of gentamicin bulk samples were elucidated and compared according to their fragmentation behavior.In total seventeen impurities present in samples,five impurities were not elucidated and two compounds were identifi... 相似文献
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Design, synthesis and characterization of novel biodegradable macrodiols based on poly(DL-lactic acid) and poly(p-dioxanone) 总被引:1,自引:0,他引:1
Chan Yu Zhang Yan Feng Luo Su Jun Wang Zhao Liu Yuan Liang Wang Zhi Qing Liang 《中国化学快报》2009,20(6):743-746
Integrating poly(lactic acid)(PLA),glycolic acid(GA) and ethylene glycol(EG) will hopefully result in a novel copolymer that combines such advantages as fastened and controllable release rate and improved flexibility together with good biocompatibility.In this study,p-dioxanone(PDO) was employed to copolymerize with DL-lactide(LA) via ring-opening melt polymerization using Sn(Oct)_2 as an initiator and ethylene glycol as a co-initiator.The obtained degradable macrodiols(HO-P(LA-co-PDO)-OH) were just such... 相似文献
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