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．     

悬浮进样阻抑火焰原子吸收光谱法测定甘薯粉条中的微量铝

本文利用铝对钙吸收的阻抑效应,建立了悬浮进样-火焰原子吸收光谱法快速测定甘薯粉条中微量铝的方法。结果表明,当底液中的钙为20.0μg/mL时,测定铝的线性范围是0.5~8.0μg/mL,检出限为0.25μg/mL。本法用于三种不同粉条中铝的测定,相对标准偏差为0.7%~1.9%,加标回收率为95%~104%。     

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.     

低温吸附、热解吸气相色谱法测定痕量气体硫化氢

采用GC-7890Ⅱ气相色谱仪和自行研制的控温炉，以Chromosorb G为吸附剂。液氮为冷冻剂，低温吸附大气中痕量硫化氢。在130℃下热解吸4min后，直接进入色谱分析。结果表明该方法精密度和回收率均较好。当样品体积为1L时。检出限为0．192ng/L.     

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.