185 resultados para Q-TOF


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肿瘤的生长依赖于血管的生成,新生血管不仅为肿瘤生长提供必需的营养物质,而且为肿瘤细胞扩散提供了重要的途径[1].1997年哈佛大学的O'Reilly等[2]发现了一种内源性新血管生成抑制因子内皮抑素(Endostatin),显示出特异抑制激活的血管内皮细胞增殖和肿瘤新血管生成的生物学活性,其抗肿瘤作用具有高效、低毒、无耐药性的优点.

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The molecular weight of recombinant hirudin ( rHV-2) was determined rapidly by matrix-assisted laser desorption/ionization time of fight mass spectrometry (MALDI-TOF-MS). The effects of the three types of matrixes were compared and discussed, alpha-cynao-4-hydroxycinnamic acid was proved to be the best matrix. It showed that MALDI-TOF-MS was superior to the traditional method of molecular weight determination of the biological macromolecules. The mass spectrum data proved that the primary structure of rHV-2 was correct and there was no amino acid deletion, mutation and modification in its expression, refolding and purification.

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利用基质辅助激光解吸电离飞行时间质谱(MALDI-TOF -MS)法测定了重组人肿瘤坏死因子α衍生物的分子质量 ,并对所得的结果进行了讨论 ,实验证明该法灵敏度高 ,重复性好 ,结果准确 ,是测定蛋白质分子质量的有效方法

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应用基质辅助激光解吸电离飞行时间质谱 ( MALDI- TOF- MS)技术对系列环状预聚体进行了表征 ,分别确定了系列环状预聚体各自不同的聚合度 ,同时对它们的结构进行了确认 ,获得了满意的结果。实验结果表明 MALDI- TOF- MS是分析环状预聚体准确、快速工具之一

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目的: 分析测定长白山白眉蝮蛇蛇毒纤溶酶和磷脂酶A2 的分子量和纯度。方法与结果: 应用MALDI/TOF MS法测定纤溶酶的分子量为23333±90,磷脂酶A2的分子量为14000±20,相对偏差在0138%以内。结论: 应用此方法未检测到杂蛋白质谱峰的存在, 酶的纯度较好, 测得结果要比电泳法准确。MALDI/TOF MS提供了一种测定蛋白质药物纯度快速准确的新方法。

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采用MALDI TOF MS法快速测定了天花粉蛋白的分子量,并讨论和对比了三种不同基质对其影响,认为用基质芥子酸是最佳适宜条件。实验结果表明本方法优于其它传统的测定生物大分子分子量方法

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利用MALDI-TOF-MS法测定了谷胱甘肽S-转移酶的分子量,并讨论和对比了三种不同基质对其影响,认为用α-氰基-4-羟基肉桂酸(α-CHC)作基质是最佳适宜条件。实验结果表明本方法优于其它传统的测定生物大分子分子量方法。

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应用介质辅助激光解吸离子化飞行时间质谱(MALDI-TOFMS),以二羟基苯甲酸为介质、N2(337nm)为激光源,对两种聚芳醚酮环状低聚物的结构进行了确认,研究了环状低聚物不同聚合度组分的分布规律,并且与GPC质量分析法作了比较,实验结果表明,MALDI-TOF质谱是分析环状低聚物的准确、快速的工具之一.

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用基质辅助激光解吸电离飞行时间质谱(MALDI-TOF-MS)技术研究了F-46和JF-43型酚醛环氧树脂。获得了该类树脂的聚合度及其不同聚合度组分的分子结构;发现该类树脂中含有环氧氯丙烷的聚合物,给出了可能的分子结构。

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应用基质辅助激光解吸电离飞行时间质谱(MALDI-TOF-MS)技术,研究了E-12、E-31、E-42、E-44和E-51五种牌号环氧树脂。获得了该类树脂的聚合度及其不同聚合度所对应的分子结构;发现了该类树脂中有一定量的环氧氯丙烷的聚合物,并给出了可能的分子结构。

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Ammonia synthesis over ruthenium catalysts supported on different carbon materials using Ba or K compounds as promoters has been investigated. Ba(NO3)(2), KOH, and KNO3 are used as the promoter or promoter precursor, and activated carbon (AC), activated carbon fiber (ACF). and carbon molecular sieve (CMS) are used as the support. The activity measurement for ammonia synthesis was carried out in a flow micro-reactor under mild conditions: 350-450 degreesC and 3.0 MPa. Results show that KOH promoter was more effective than KNO3. and that Ba(NO3)(2) was the most effective promoter among the three. The roles of promoters can be divided into the electronic modification of ruthenium, the neutralization of surface functional groups on the carbon support and the ruthenium precursor. The catalyst with AC as the support gave the highest ammonia concentration in the effluent among the supports used, while the catalyst with ACF as the support showed the highest turnover-frequency (TOF) value. It seems that the larger particles of Ru on the carbon supports are more active for ammonia synthesis in terms of TOF value. (C) 2001 Elsevier Science B.V. All rights reserved.