Cadinane Sesquiterpenes from the brown alga Dictyopteris divaricata

Seven new cadinane sesquiterpenes, (-)-(1R,6S,7S,10R)-1-hydroxycadinan-3-en-5-one (1), (+)-(1R,5S,6R,7S, 10R)-cadinan-3-ene-1,5-diol (2), (+)-(1R,5R,6R,7S,10R)-cadinan-3-ene-1,5-diol (3), (+)-(1R,5S,6R,7S,10R)-cadinan-4(11)-ene-1,5-diol (4), (+)-(1R,5R,6R,7R,10R)-cadinan-4(11)-ene-1,5,12-triol (5), (-)-(1R,4R,5S,6R,7S, 10R)-cadinan-1,4,5-triol (6), and (-)-(1R,6R,7S,10R)-11-oxocadinan-4-en-1-ol (7), together with nine known compounds were isolated from the brown alga Dictyopteris divaricata. The structures of the new natural products, as well as their absolute configuration, were established by means of spectroscopic data including IR, HRMS, 1D and 2D NMR, single-crystal X-ray diffraction, and CD. All compounds were inactive against several human cancer cell lines including lung adenocarcinoma (A549), stomach cancer (BGC-823), breast cancer (MCF-7), hepatoma (Bel7402), and colon cancer (HCT-8) cell lines.

Preparation of low-molecular-weight and high-sulfate-content chitosans under microwave radiation and their potential antioxidant activity in vitro

In the present paper microwave radiation has been used to introduce N-sulfo and O-sulfo groups into chitosan with a thigh degree of substitution and low-molecular weight. The sulfation of chitosan was performed in microwave ovens. It was found that microwave heating is a convenient way to obtain a wide range of products of different degrees of substitution and molecular weight only by changing reaction time or/and radiation power. Moreover, microwave radiation accelerated the degradation of sulfated chitosan, and the molecular weight of sulfated chitosan was considerably lower than that obtained by traditional heating. There are no differences in the chemical structure of sulfated chitosan obtained by microwave and by conventional technology. FTIR and C-13 NMR spectral analyses demonstrated that a significantly shorter time is required to obtain a satisfactory degree of substitution and molecular weight by microwave radiation than by conventional technology. In this present paper, we also determined antioxidant activity of low-molecular-weight and high-sulfate-content chitosans (LCTS). The results showed LCTS could scavenge superoxide and hydroxyl radical. Its IC50 is 0.025 and 1.32mg/mL, respectively. It is a potential antioxidant in vitro. (C) 2004 Published by Elsevier Ltd.

不同生长时期盐藻无机元素分析

测定了对数生长期和稳定期盐藻中10种无机元素K、Na、Ca、Mg、P、Cu、Zn、Fe、Mn、Se的含量.结果表明,稳定期盐藻中K、Ca、Mg、Cu、Zn、Fe、Mn、Se的含量比对数生长期都有不同程度的增加,Na、P的含量反而降低.

藏药抱茎獐牙莱HPLC指纹图谱研究

采用反相高效液相色谱-二极管阵列的检测方法,对不同产地的10批野生和栽培抱茎獐牙菜药材的水溶性成分进行了分析,建立了抱茎獐牙菜药材的指纹图谱.色谱柱为VP-ODS C18柱(5 μm,150 mm×4.6 mm),流动相为甲醇-0.02%的磷酸水溶液,检测波长254 nm.用文中的最佳条件可较全面地反映抱茎獐牙菜的主要成分,为藏药抱茎獐牙菜的质量控制提供了科学依据.

藏药花锚指纹图谱研究

采用反相高效液相色谱二极管阵列的检测方法,对不同产地的10批野生花锚药材的水溶性成分进行了分析,建立了花锚药材的指纹图谱,并对栽培花锚进行了指纹图谱的特征比较.结果证明,栽培花锚中的主要化学成分及数量符合花锚药材的指纹特征,可以代替野生花锚药材入药.

大鸨生长期能量代谢和蛋白质沉积量的初步研究

对不同日龄笼养大鸨(Otis tarda)的能量代谢和蛋白质沉积量进行研究.结果表明,50日龄、70日龄、300日龄和400日龄雄性大鸨的能量日摄入量分别为1 498.9 kJ、2 376.2 kJ、2 397.4 kJ和2 465.9 kJ;能量代谢率分别为82.3%、81.8%、81.8%和83.1%;蛋白质的日沉积量分别为5.8 g、13.4 g、15.8 g和13.5 g. 表3 参9

茶藨属植物果实提取物及其制备工艺及其应用

本发明涉及一种茶藨属植物果实提取物及其制备工艺和应用；它是将青藏高原的茶藨属植物的果实干燥后粉碎，再用醚类溶剂浸泡提取，萃取得果实油脂；然后将果实油脂加醚并加KOH－CH3－OH溶液摇动后静置10－20分钟；将静置的溶液加水静置分层，取上层清液得提取物；本发明富含不饱和脂肪酸，含量在92％以上；其提取工艺简单、提取率高达98.5％；本发明的提取物可用于降血脂、抑制血小板凝聚、治疗高血脂和血栓病。

基于遗传退火算法的装配线设计多目标优化方法

针对混装配线设计这一有约束的多目标优化问题,建立了数学模型。将基于Pareto的解的分级方法与Lp-范数形式的非线性机制相组合,构建了基于遗传退火算法多目标优化方法。重点阐述了个体编码、染色体检修、多目标处理机制等关键技术。设计了算法流程图,并开发了优化程序。该方法克服了加权和方法的不足,用模拟退火改善了遗传算法全局寻优性能。计算实例表明,随着迭代次数的增加,每代的非受控点逐渐收敛于Pareto最优边界,是一种混装线设计多目标优化的新方法。

Model 1027连续测氡仪测量室内氡浓度若干问题的探讨

本文探讨Model 1027 连续测氡仪测量室内氡浓度的方法。用两台仪器对一房间内氡浓度在不同情况下进行近一个月的测量后,得出以下结论:仪器操作简便,测量结果稳定;仪器处于DISABLE(数字显示关闭) 状态所测氡浓度高于ENABLE(数字显示开启) 状态测量氡浓度;测量结果表达方式有两类,即氡浓度总平均值和美国环保局推荐平均值,多点比较测量应采用同一类氡浓度;仪器连续测量时间不得少于24h ,最好为48h 或更长;本次所测房间氡浓度平均值为9215 Bq/ m3 ,符合国家标准。

氮同位素示踪贵州红枫湖河流季节性氮污染

利用氮同位素技术对贵州红枫湖各输入、输出河流氮污染状况和季节性变化规律进行了研究,并通过对输入河流和输出河流的氮对比,探讨红枫湖的氮负荷变化。农业输入河流季节氮污染变化较小,以低硝酸盐、低铵盐含量为特征,其氮同位素组成较小,位于农业源范围之内( < + 10 ‰) 。工业污染河流氮污染呈干季和雨季变化:干季(冬春季) 以高硝酸盐、高铵盐含量和高氮同位素组成( > + 10 ‰) 为特征,雨季(夏季) 则相似于农业输入河流。因而利用氮同位素组成可以对不同类型河流氮污染源进行可靠识别。

准噶尔盆地构造动力学过程

准噶尔盆地被古生代缝合线构造包围，周缘山系向盆地方向逆冲推覆，显示了盆地处于长期受压的构造环境；火山喷发由海相转变为大陆相，火山活动由强到弱，表明二叠纪以后，上地幔物质一直处于收缩状态，盆地整体持续下沉接受沉积，地壳增厚。二叠纪进入盆地演化阶段之后，经历了晚海西、印支、燕山和喜马拉雅四期构造应力场的作用，发生了南北向拉张变形、南北向和北西向碰撞挤压变形、南北向和北西向张压交替变形以及南北向压扭冲断、走滑和重力滑覆变形，形成复杂多样构造类型。