Distribution of plankton lipids and their role in the biological transformation of Antarctic primary production

Production and transfer of lipid through the Antarctic food web is reviewed for the Indian Ocean sector. The slow settling fine particles showed a marked inter-annual variability in biochemical composition with an increase in lipid content as % organic carbon. Comparison of the fatty acid spectra of different size categories of organic particles indicated that fine particles are dominated by saturated, monoenoic and branched acids, while larger material (50–100 μm, 200–500 μm net collected fractions) displayed a signature dominated by polyunsaturated acids. Zooplankton taxa displayed different strategies of lipid accumulation. Lipid content was highest in Thysanoessa macrura females and copepodite stages of Calanus propinquus. Relatively low levels were recorded for juveniles and male stages of euphausiids. Reserve lipids varied with species: C. propinquus showed equal content of triglycerides and wax esters, T. macrura showed a dominance of wax esters and Euphausia superba and Themisto gaudichaudii accumulated only triglycerides. Computed as carbon equivalent and integrated over 200 m, lipids in slow settling particles represented 22.6% of annual primary production. Similar computation with mesozooplankton and E. superba data on biomass and population structure from several summer cruises indicated values of carbon accumulation as lipid reserves and egg production of 4.2 and 0.1% of annual primary production for copepods and 4.4 and 3.8% for E. superba. When all trophic levels are considered, the overall mean exceeded 30% of annual primary production.     

醇类燃料在摩托车中的应用研究

石化燃料日益枯竭,开发和使用可再生生物燃料迫在眉睫。通过介绍醇类燃料的性质以及国内外研究使用醇类燃料的现状,分析醇类燃料在摩托车中的应用前景,并提出具体的改进方案,可供同行参考。     

鸦胆子油脂质体对人肝癌细胞株HepG2抑制作用的体内外研究

目的通过体外体内实验探讨鸦胆子油脂质体对人肝癌细胞株HepG2的影响及可能机制。方法利用鸦胆子油脂质体高剂量(5mg/L)、低剂量(2.5mg/L)体外作用于人肝癌细胞株HepG2,MTT比色分析法分析HepG2细胞生长抑制程度,流式细胞仪检测不同药物浓度作用下细胞的凋亡率,透射电镜下观察HepG2细胞形态变化。通过腹腔注射荷瘤裸鼠进行体内试验,观察鸦胆子油脂质体小剂量(12.5mg/L)、大剂量(25mg/L)对其肝脏的病理改变;TUNEL法检测肝脏肿瘤组织凋亡细胞。结果 MTT比色分析法实验结果显示鸦胆子油脂质体可明显抑制HepG2细胞增殖;透射电镜下观察5mg/L鸦胆子油脂质体在体外作用于HepG2细胞6h后,可见明显凋亡细胞形态出现。流式细胞仪检测随鸦胆子油脂质体作用强度和时间的增加,细胞抑制率逐步由33.31%提升至90.62%(P<0.01)。鸦胆子油脂质体腹腔注射组较阴性对照组动物模型死亡时平均体重增加,肿瘤转移率下降(P<0.01);TUNEL法亦提示鸦胆子油脂质体组凋亡细胞率增加(P<0.01)。结论鸦胆子油脂质体对HepG2细胞在体内体外具有抑制增殖的作用,并可诱导肿瘤细胞凋亡。     

消油剂对环境生物毒性评价研究

选取不同营养级的3种海洋生物(小球藻、褶皱臂尾轮虫和半滑舌鳎)为受试生物,以ED50或LD50作为测试指标,对原油、消油剂和乳化液对不同海洋生物的毒性效应进行比较分析。结果表明:实验用原油、消油剂和乳化液对3种海洋生物均有明显的致毒效应;对不同类型原油,轻质油在24~48 h对不同海洋生物的毒作用效应最为明显,中质油大约有24 h的滞后毒作用效应,重质油在96~240 h时毒作用效应最显著;消油剂对不同海洋生物的生物毒性均低于原油和乳化液,说明消油剂使用形成的乳化液的毒性要高于消油剂单独存在时的毒性。     

Heavy commercial vehicles‐following behavior and interactions with different vehicle classes

This work investigates the effect of heavy commercial vehicles on the capacity and overall performance of congested freeway sections. Furthermore, the following behaviors of heavy commercial vehicles and its comparison with passenger cars are presented. Freeways are designed to facilitate the flow of traffic including passenger cars and trucks. The impact of these different vehicle types is not uniform, creating problems in freeway operations and safety particularly under heavy demand with a high proportion of heavy vehicles. There have been very few studies concerned with the traffic behavior and characteristics of heavy vehicles in these situations. This study draws on extensive data collected over a long stretch of freeway using videotaping and surveys at several sites. The collected data were firstly used to study the interaction between heavy vehicles and passenger cars. Through a detailed trajectory analysis, the following behaviors of 120 heavy vehicles were then analyzed to provide a thorough understanding of heavy vehicles‐following behavior mechanism. The results showed a significant difference in the following behavior of heavy vehicles compared with other vehicles. Copyright © 2011 John Wiley & Sons, Ltd.     

Acoustic excitation of hull surfaces by propeller sources

We present preliminary results from our new ship motion model that includes both strong and weak three-dimensional interactions between environmental surface waves and ship bodies in arbitrary water depth. The linear solutions of steady flow using the new model agree well with those obtained using the Green function methods. When the Froude number Fn is large, the fully nonlinear solutions of our model are significantly different from linear solutions, even in calm water. The interactions between the ship and incident gravity waves are completely different from those in linear solutions even with small Fn and moderate-amplitude surface waves (e.g., Fn = 0.25 and a significant wave height of about 1–3m).     

高速公路服务区污水回用的技术经济可行性分析

高速公路服务区远离市政给水管网,用水紧张,有污水回用的现实需求。结合江苏省某高速公路服务区研究服务区用水量、污水产生量和污水回用量的构成和关系,对常规三级处理和膜生物反应器两种污水回用工艺进行比较,探讨高速公路服务区污水回用的技术经济可行性。分析结果表明,高速公路服务区使用污水回用技术,有显著的环境效益和社会效益,同时还可产生一定的经济效益。     

大肠癌E-钙黏附分子表达及其临床意义

目的　探讨大肠癌E 钙黏附分子 (E cadherin ,E CD)的表达及其与大肠癌细胞分化程度、大体类型、淋巴结转移及Dukes分期间的关系。方法　应用免疫组化法 ,测定 3 1例经病理证实的新鲜大肠癌标本中E CD的表达。结果　正常大肠黏膜E CD强阳性表达率为 10 0 % ,3 1例大肠癌E CD总减低表达率为 77.4% ;分化较好的和分化不良的大肠癌细胞E CD减低表达率分别为 57.2 %和 94.1% ;肿块型、溃疡型、浸润型癌E CD减低表达率分别为 44.5%、93 .7%、88.3 % ;无淋巴结转移、有淋巴结转移E CD减低表达率分别为 62 .5%、93 .3 %。E CD表达与大肠癌的细胞分化程度、大体生长方式、有无淋巴结转移相关 (P <0 .0 1) ,与Dukes分期无明显相关性 (P >0 .0 5)。结论　E CD表达可作为大肠癌恶性程度及预后判断的有效指标     

B7.1胞外编码区的真核表达及其生物活性

目的　真核表达B7.1细胞外编码区以研究其生物学活性。方法　电穿孔法将重组质粒pDisplay/B7.1(V +C)导入人子宫颈癌细胞株 ,免疫组化及核酸原位杂交法分别检测其蛋白及mRNA表达 ,3 H TdR掺入法测定表达物对T细胞的刺激作用 ;MTT法研究转染细胞 T细胞混合培养引发的细胞毒性杀伤作用。结果　B7.1细胞外区在Hela细胞表面表达 ,所表达的B7.1细胞外区在抗CD3单抗存在的情况下具有刺激T细胞活化的特性 ,重组质粒转染的Hela细胞与T细胞混合培养可引起细胞毒性杀伤。结论　真核表达的B7.1(V +C)具有T细胞共刺激活性 ,可用于构建肿瘤免疫治疗之双功能分子。