三种海洋微藻生长期脂肪酸组成研究

球等鞭金藻、盐藻和小球藻脂肪酸组成气相色谱分析的结果表明 ,三种海洋微藻在指数生长期总多不饱和脂肪酸含量 (TPUFA)明显比稳定生长期高 ,而总饱和脂肪酸含量 (TSFA)在指数生长期间相对较低。球等鞭金藻的DHA ,小球藻的EPA和盐藻的C18∶3均在培养后的第 6d均达最大值。     

Detection of geosmin and 2-methylisoborneol by liquid-liquid extraction-gas chromatograph mass spectrum (LLE-GCMS)and solid phase extraction-gas chromatograph mass spectrum (SPE-GCMS)

Two sample preparation methods were introduced and compared in this paper to establish a simple, quick and exact analysis of geosmin and 2-methylisoborneol. LC-18 column was employed in solid phase extraction (SPE), 1.0 mL of hexane was adopted in liquid-liquid extraction (LLE), and the extracts were analyzed by gas chromatograph mass spectrum (GCMS) in selected ion mode. Mean recoveries of SPE were low for 2-methylisoborneol (2-MIB) and geosmin (GSM) with values below 50%. For LLE, the recoveries were satisfyingly above 50% for 2-MIB and 80% for GSM. Detection limits of the LLE method were as low as 1.0 ng/L for GSM and 5.0 ng/L for 2-MIB. A year-long investigation on odor chemicals of drinking water in Shanghai demonstrated that in the summer, there was a serious odor problem induced by a high concentration of 2-MIB. The highest concentration of 152.82 ng/L appeared in July in raw water, while GSM flocculation was minimal with concentrations below odor threshold.     

Aerosol optical properties derived from simultaneous sunphotometer and aureolemeter measurements in Lhasa

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Surviving the change to warning colouration: density-dependent polyphenism suggests a route for the evolution of aposematism

Summary. How warning colouration first appeared remains a disputed question in evolutionary biology. A density-dependent transition from crypsis to aposematism that occurs during phase change in the desert locust (Schistocerca gregaria) provides insight into the conditions under which acquiring warning colouration is adaptive. When crowded for only a few hours, solitarious locusts cease avoiding each other and actively aggregate. This occurs well before they acquire warning colouration. We show that accompanying this early behavioural gregarisation is a remarkable shift in feeding behaviour, in which solitarious insects switch from being deterred by a toxic plant alkaloid to feeding avidly upon foods containing it. A computer simulation shows how crypsis ceases to be effective as an anti-predator strategy when solitarious locusts are crowded, how chemical defence becomes essential as conspicuousness increases with local density, and how warning colouration becomes advantageous under these conditions. These findings provide empirical evidence for an adaptive route for the change from a cryptic edible phenotype to a brightly coloured toxic one.     

Shifts in a Pacific Ocean Fish Assemblage: the Potential Influence of Exploitation

Abstract:  As in many regions of the world, marine fishes and invertebrates along the Pacific coast of the United States have long been subjected to overexploitation. Despite this history, however, we lack basic information on the current status of many fishes along this coastline. We used data from a quarter century of fishery-independent, coast-wide trawl surveys to study systematically the demersal fish assemblages along the U.S. Pacific coast. We documented fundamental shifts in this fish assemblage. Average fish size, across a diversity of species, has declined 45% in 21 years. There have been major shifts in the constituent species of the assemblage, with some species achieving annual population growth rates of >10% and others declining in excess of 10% per year. Annual rate of change in population size appeared to be a function of life history interacting with fishing pressure. Negative trends in population size were particularly apparent in rockfish ( Sebastes spp.). However, across all taxa examined, trends in population size were associated with size of maturity, maximum size, and growth rate. Trends in population size were associated inversely with harvest levels, but stocks that mature late tended to decline faster than would be predicted by catch rates alone. Our results are disquieting because they raise the possibility that fishing-induced phase shifts in fish communities may affect the recovery of fishes, even after the implementation of severe fishing restrictions.     

微波辅助-顶空固相微萃取-气相色谱-脉冲火焰光度法测定海水中二甲基硫和藻体中二甲基巯基丙酸

建立了海水中二甲基硫和海洋微藻藻体中二甲基巯基丙酸的微波辅助 顶空固相微萃取 气相色谱 脉冲火焰光度检测的分析方法 .二甲基硫的检测限达 0 0 1ng·ml- 1( 3S/N) ,海水和藻体样品多次平行测定的相对标准偏差分别为 3 95 %和 7 32 % .已初步应用于实验室培养的不同生长时期甲藻藻体中二甲基巯基丙酸和培养液中二甲基硫含量的测定 .     

水中杀菌剂叶青双及其降解物的反相液相色谱测定

本文用反相液相色谱法测定水中叶青双及其降解物2-氨基5-巯基-1,3,4-噻二唑。平均回收率分别为91％和94％;对水样的最低检测浓度分别为2ppb和0.8ppb;叶青双与2-氨基-5-巯基-1,3,4-噻二唑的分离度为2.5。本法在柱效和灵敏度上比硅胶柱液相色谱法有明显的提高。     

活性炭载体三相流化床催化氧化含氰废水的工艺理论研究

以三相流化床作为反应器处理含氰废水的工艺理论及操作特性，通过正交试验确立了工作条件，并进行了相关因素的影响程度分析。活性炭作载体的三相流化床处理含氰废水因提高传质速度和解决深层供氧问题而加快吸附速度和催化氧化反应速度，明显提高活性炭对氰化物的处理效率，在相同条件下处理容量比固定床法高４６．３％。这种方法可应用于中小型电镀厂排出中高浓度含氰废水的处理。     

火灾中硅酸盐水泥制品的膨胀爆炸与开裂

本文介绍了四川消防科研所自1972年以来开展的钢筋混凝土建筑构件和建筑材料耐火性能研究工作中关于硅酸盐水泥制品在火灾温度条件下膨胀、爆炸与开裂方面的实验研究情况。通过对有关各类以硅酸盐为重要成分的建筑构件和制品的反复试验研究与理论分析，初步掌握了一定程度的膨胀、爆炸以及开裂的物理、化学变化特征。着重指出了应用于建筑中的硅酸盐水泥制品－诸如混凝土构建或装修板材之类，它们的这些特性对建筑物的防火、灭火都有很大的威胁，应该对其产生的根本原因和预防对策进行更加深入的研究，以避免因制品的破坏而导致火灾蔓延和减少消防人员在扑救火灾过程中所造成的不必要的伤亡。     

顶空固相微萃取-气相色谱质谱法测定水体中的苯甲醚

建立了顶空固相微萃取-气相色谱质谱法定性定量检测水中苯甲醚的分析方法。对影响检测结果的因素如萃取头的选择、萃取时间等进行了优化。经过条件优化，方法在1～1 000 μg/L 范围内线性良好，线性相关系数＞0.999，实际水样加标质量浓度分别为10，60，300 μg/L时，加标回收率为85%～120%，相对标准偏差（RSD）为3.95%～6.72%。全扫描模式下，苯甲醚的检出限为0.3 μg/L。实验结果表明，该方法快速、简便、灵敏度高，方法精密度和准确度均能满足水中微量及痕量苯甲醚检测的要求。