喜树碱与胰蛋白酶的相互作用

喜树碱(camptothecin,CPT)是从珙桐科乔木喜树中分离得到的一类重要抗癌药物,对动物肿瘤及白血病均有明显的抑制作用[1]。CPT分子为五环结构,含有一个吡咯[3,4-b]喹啉环,一个共轭吡啶环和一个α-羟基六元内脂环[2]。CPT通过嵌合抑制DNA拓扑异构酶Ⅰ的活性,对卵巢癌、结肠直肠癌     

清代北京私家名园万柳堂考述(上)*

核电站发生严重事故时,会产生大量氢气,需要进行处理,而氢气催化氧化技术是一种较好的处理方式可用于核电站的氢气处理,其关键是依靠氢氧化合催化剂得以实现.我们综述了催化剂的活性成分、载体和制备方法,以及催化剂的改性方法对催化性能的影响.目前催化剂的改性研究主要集中于对金属粒子的尺寸和分散性的改善,尽可能利用载体表面的金属粒子以获得高的催化剂活性.同时,催化反应容易受到"有毒"物质干扰,可以通过活性成分合金化、改变负载在载体表面的金属粒子形貌(如核壳结构)等方式改善,从而达到提升催化活性的目的.     

两个单核镉、锌配合物M（2－SC_5H_3NH－3－SiMe_3）_2Cl_2（M＝Cd，Zn）的合成与晶体结构

以大空阻的３．三甲基硅－吡啶－２－硫酚为配体，合成了２个单核镉、锌配合物，并用Ｘ射线单晶衍射法测定了其晶体结构．     

银-磷催化剂催化乙二醇制乙二醛及其表面性质

用银－磷催化剂研究了原料气线速、空速、氧醇摩尔比、反应温度、乙二醇重量浓度对催化氧化乙二醇制乙二醛的反应活性的影响．结果表明，在相近的反应条件下，银－磷催化剂能使副产物ＣＯ２的产率从电解银的３０％降到１３．３％，而使乙二醛收率从５４％增至８１％．Ｘ射线光电子能谱表明，在银表面上形成了稳定的表面磷化合物并占据了一部分深度氧化的活性位，因而提高了反应的选择性．     

无溶剂体系中脂肪酶催化红花油水解反应

无溶剂体系中脂肪酶催化红花油水解反应;水解;红花油;无溶剂体系;脂肪酶     

草酸镁空心纳米结构的一步低热固相化学合成(英)

Nanostructuredmaterialsareafocusedresearchfieldduetotheirunusualpropertiesandpotentialap-plicationsrangingfrommesoscopicresearchtothede-velopmentofnanodevices[1,2].Especially,allsortsofnanoscalematerialswithspecificstructureorinter-estingmorphologyhavepro…     

A New Eremophilanoid Sesquiterpene from Senecio oldhamianus

A new Eremophilanoid sesquiterpene(1) was isolated from the whole plant of Senecio oldhaminus. Its structure was elucidated as 7β,11-epoxy-9α,10α-epoxy-8-oxoeremophilane using spectroscopic methords and X-ray analysis.     

Sesquiterpenes from Carpesium longifolium

The genus Carpesium (Compositae) with only 21 species is widely distributed in Asia, mainly in the southwest ern mountainous regions of China. The seeds, roots, leaves and stems of some Carpesium species have long been used as Chinese traditional medicine for hemostatic, vermifuge, anti-inflammatory and detoxication properties. [1,2]Here, we report the first phytochemical investigation of Carpesium longifolium Chen et C. M. Hu, which led to the isolation and structural elucidation of four new sesquiterpene lactones 1 ～ 4 and five known compounds 5 ～ 9, the cy totoxic activity test of three compounds 5, 6 and 7, and compounds 5 and 7 exhibited significant cytotoxic activity against cultured SMMC-7721 (human hepatoma cell) and HO-8910 (human ovarian carcinoma cell).     

Solvent-free Rapid Synthesis of Styryl Dyes with Benzimidazole Nucleus Using Microwave Irradiation

The reactions of 2-methylbenzimidazole or 2-methylbenzimidazolium iodide with aromatic aldehydes are accelerated under microwave irradiation by using Ac2O or piperidine as dehydrant or catalyst in the absence of any solvent. The approach provides an attractive and environmentally friendly pathway to several useful styryl dyes with benzimidazole nucleus.     

沿海港口表层沉积物中三丁基锡化合物的顶空固相微萃取气相色谱测定

利用顶空固相微萃取与气相色谱火焰光度检测法测定广东汕头港表层沉积物中的三丁基锡化合物(TBT) ,探索了样品的最佳超声处理时间、缓冲溶液 pH值及萃取时间 ,该法可方便、灵敏地测定沉积物中的三丁基锡 ,检出限达到0.28×10 -9(w)。