928 resultados para Single Molecule Magnets (SMMs), 1H NMR, 13C NMR, residual dipolar couplings (RDCs)


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基于核磁共振技术的代谢组学是近年发展起来的一种新的组学技术,主要利用生物体液的核磁共振谱提供生物体内全部小分子代谢物的丰富信息。然而,噪声的存在影响了模式识别方法分析的准确度。近年来小波变换以其多分辨率分析的特性、方法简单、快速等优点成为一种有效的去除分析信号噪声的方法。本实验通过运用小波变换去除噪声、校正基线后,再进行Fisher判别分析,得到了较传统分析更为清晰的代谢标识物,建立了良好的代谢模型

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对环化氯丁橡胶的1H -NMR谱进行了归属 ,并推导出计算环化氯丁橡胶 (CR)的环化度和溶剂参与量的公式。

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随着稀土应用的日益扩大,稀土将有可能越来越多地进入生态环境和生物体内,但其作用机理及对生物体正常生理功能的影响还不清楚,因此研究稀土的生物效应是一个迫切需要解决的重要基础课题。本文采用现代核磁共振技术,通过分析灌胃给药0.2,2.0,10,20mg/kg 剂量的 La(NO_3)_3六个月后大鼠血清中某些内源性化合物的变化研究了稀土化合物在动物体内的作用情况及长期毒性,同时对20mg/kg 剂量组三个月后大鼠尿液的 H NMR 谱图进行了分析,并通过血液中一些重要生化指标的测定对结果进行了验证。图1(a)为正常大鼠血清的 H NMR 谱,图1(b)为给药(10mg La(NO_3)_3/kg)六个月后大鼠血清的 H NMR 谱图。从图中一些内源性化合物的物种和浓度的变化可以看出,稀土在体内长期作用后,可能导致动物肝脏和肾脏物特定部位受到了一定程度的损害,并使体内酶代谢发生紊乱,且随着稀土量的增多,损害程度也越严重。另外通过20mg La(NO_3)_3/kg 组三个月后大鼠尿液的 H NMR 分析及血液中生化指标的检测结果也可得出动物机体受损的信息。本方法也可应用于非先天疾病的异常代谢的临床检测及其它药...

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合成了两种新的DTPA双酰胺衍生物,DTPA-BDMA和DTPA-BDEA.通过~1HNMR滴定研究发现这两种化合物的质子解离过程为:中部胺基(PH<0.5),端部羧基(0.5<PH<3.1),中部羧基(3.1<pH<5.4),端部胺基(5.4<pH<8.5)和中部胺基(8.5<pH<12.5).在质子解离过程中端部胺基上的一个质子能转位到中部胺基上,同时分子结构将发生较大变化。Gd(DTPA-BDMA)和Gd(DTPA-BDEA)的弛豫效率分别为4.01和4.97L·mmol-1.s-1(400MHz,pH=7.3,25℃),说明这两种化合物是非常有应用前景的MRI造影剂.

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关于双甘肽的~(13)C化学位移行为及其与稀土离子的配位作用前人有过报导。但有关水溶液中双甘肽稀土配合物的结构仍不清楚。本文测定了在重稀土离子Dy~(3+)、Ho~(3+)、Er~(3+)、Tm~(3+)和Yb~(3+)作用下双甘肽~(13)C和~1H的顺磁诱导位移,研究了水溶液中双甘肽稀土配合物的组成及结构。1 实验部分

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Human activities are fundamentally altering the chemistry of the world's oceans. Ocean acidification (OA) is occurring against a background of warming and an increasing occurrence of disease outbreaks, posing a significant threat to marine organisms, communities, and ecosystems. In the current study, (1)H NMR spectroscopy was used to investigate the response of the blue mussel, Mytilus edulis, to a 90-day exposure to reduced seawater pH and increased temperature, followed by a subsequent pathogenic challenge. Analysis of the metabolome revealed significant differences between male and female organisms. Furthermore, males and females are shown to respond differently to environmental stress. While males were significantly affected by reduced seawater pH, increased temperature, and a bacterial challenge, it was only a reduction in seawater pH that impacted females. Despite impacting males and females differently, stressors seem to act via a generalized stress response impacting both energy metabolism and osmotic balance in both sexes. This study therefore has important implications for the interpretation of metabolomic data in mussels, as well as the impact of environmental stress in marine invertebrates in general.