Terminal double bonds in the alkenes and acetates of defensive secretion from the thrips Suocerathrips linguis Mound & Marullo, 1994 (Thysanoptera: Phlaeothripidae)

Defensive secretions of adult males and females of the subsocial thrips Suocerathrips linguis were examined using gas chromatography–mass spectrometry (GC–MS). The samples contained six long-chain acetates and five aliphatic alkanes and alkenes. Whole-body extracts yielded six methyl esters of fatty acids as well as hexadecyl acetate. Structures of the two main components, (11Z)-icosa-11,19-dienyl acetate and octadecyl acetate, were confirmed. The third most abundant substance was identified as octadec-17-enyl acetate, which is a new natural product. In addition, (9Z)-octadec-9-enyl acetate was identified along with other acetates. Pure icosadienyl acetate was found to remain liquid down to −15°C, and is the solvent for the solid components of the secretion cocktail. A tentative biosynthetic pathway for all of the 12 acetates, alkanes and alkenes is discussed, considering especially the components with terminal double bonds that are uncommon in Thysanoptera and other insects.     

二氧化硫和铅联合染毒对小鼠遗传物质的损伤

运用单细胞凝胶电泳技术研究了SO₂和醋酸铅亚急性联合染毒对雄性小鼠脑、肺、脾、肾细胞DNA的损伤.结果表明,在42mg/m³ SO₂和0.2%醋酸铅单独及联合作用下,小鼠脑、肺、肾、脾细胞DNA迁移距离均比对照组显著增加,而且铅可以加剧SO₂对脑、肾、脾细胞核DNA的损伤程度;SO₂对肺细胞核DNA的损伤程度要比铅的损伤大,小鼠肺细胞核DNA迁移距离在SO₂和醋酸铅联合作用组与醋酸铅单独作用组间有极显著性差异(P<0.01),而与SO₂单独作用组间没有显著性差异.SO₂和醋酸铅均可引起小鼠组织细胞的DNA损伤,它们对脑、肺、脾、肾的损伤程度不同,在一定条件下存在明显的协同效应,可以增强彼此的毒性作用.这意味着SO₂和铅均有引起哺乳动物细胞基因突变的潜在危险,大气SO₂污染与铅的污染可能加剧某些疾病的发生与发展.     

Predicting bioavailability of PAHs in field-contaminated soils by passive sampling with triolein embedded cellulose acetate membranes

Triolein embedded cellulose acetate membrane (TECAM) was used for passive sampling of the fraction of naphthalene, phenanthrene, pyrene and benzo[a]pyrene in 18 field-contaminated soils. The sampling process of PAHs by TECAM fitted well with a first-order kinetics model and PAHs reached 95% of equilibrium in TECAM within 20 h. Concentrations of PAHs in TECAM (C_TECAM) correlated well with the concentrations in soils (r² = 0.693-0.962, p < 0.001). Furthermore, concentrations of PAHs determined in the soil solution were very close to the values estimated by C_TECAM and the partition coefficient between TECAM and water (K_TECAM-w). After lipid normalization nearly 1:1 relationships were observed between PAH concentrations in TECAMs and earthworms exposed to the soils (r² = 0.591-0.824, n = 18, p < 0.01). These results suggest that TECAM can be a useful tool to predict bioavailability of PAHs in field-contaminated soils.     

茅草添加与温度变化对餐厨垃圾厌氧水解产酸的影响简

比较了茅草添加在温度变化条件下对餐厨垃圾厌氧水解过程小分子有机酸产量的影响,提出一种新型餐厨垃圾的资源化方式。研究结果显示,餐厨垃圾在55℃条件下厌氧水解主要产物为乳酸,达到25.7 g/L,其干物质转化率可以达到32.1% （g TS）,而餐厨+茅草处理在同样条件下的乳酸产量为20.1 g/L,干物质转化率为25.1%。温度下降为37℃后继续进行的的厌氧水解,得到的主要产物是乙酸、丙酸和丁酸,餐厨处理和餐厨+茅草处理这两者的峰值分别为6.5、2.8、8.0和6.1 g/L、2.7 g/L和5.9 g/L。结果显示茅草添加可以在一定程度上调节水解产物的比例,而温度变化可以调控小分子有机酸的产量。本研究结果表明,厌氧水解是一种有潜力的小分子有机酸生产与餐厨垃圾资源化处理途径。     

醋酸纤维素包埋非水溶性介体催化强化生物反硝化特性

利用醋酸纤维素包埋法固定非水溶性醌类介体,研究其催化强化Paracoccus versutus菌株GW1的反硝化作用。结果表明,醌浓度在26.7 mmol/L时,固定化蒽醌(AQ)、1-氯蒽醌(1-AQ)、2-氯蒽醌(2-AQ)、1,5-二氯蒽醌(1,5-AQ)、1,8-二氯蒽醌(1,8-AQ)和1,4,5,8-四氯蒽醌(1,4,5,8-AQ)催化反硝化效率依次为:1,5-AQ1,8-AQ1,4,5,8-AQAQ1-AQ空白对照2-AQ。反应10 h时,1,5-AQ可使硝酸盐去除率比空白对照提高1.84倍;硝酸盐氮反硝化动力学拟合为零级反应,其速率常数Kx随1,5-AQ浓度的增加均呈线性增加(Kx=0.1885C1,5-AQ+8.378);水中溶解氧会降低GW1菌反硝化的效果;投加1,5-AQ的反硝化体系中亚硝酸盐积累的最大值比不投加介体的低48.3%;醋酸纤维素介体小球经过4次的重复利用,催化效果始终是空白对照的1.5倍以上。醋酸纤维素固定化非水溶性醌可以有效加速生物反硝化,表明其是一种较优的醌固定化方法,具有良好的应用价值。     

活性炭纤维对气体中醋酸丁酯吸附性能的研究

通过试验选择活性炭纤维作为吸附剂,吸气气体中醋酸丁酯。对影响其吸附性能的主要因素进行了研究。     

膜萃取和CaO-MgO乳状液反萃取法由醋酸废水生产醋酸钙镁盐

采用磺化聚醚砜中空纤维膜萃取醋酸废水,再用CaO—MgO乳状液反萃取制备醋酸钙镁盐。考察了膜萃取和反萃取的最佳实验条件。单级膜萃取醋酸废水（醋酸质量分数2％）的最佳条件为：水相走管程有机相走壳程（水外油内）逆流、有机相流量与水相流量比1．3、水相流量0．23mL/min,在此条件下萃取率可达74％;采用二级萃取,总萃取率可达95％。反萃取的最佳条件为：采用质量浓度100g／L的CaO—MgO乳状液作反萃取剂,CaO—MgO与醋酸摩尔比1．0：2．0,投料钙与镁摩尔比2．9：7．0,反萃取时间30min,室温,在此条件下反萃取率高于97％。     

活性炭生物转盘法处理化工废水

使用固定剂将颗粒状活性炭固定在盘片上，制成了一种新型生物转盘盘片——活性炭生物转盘盘片。采用一级微型生物转盘法处理模拟化工废水，对比了活性炭、石英砂、聚丙烯3种生物转盘的处理效果。实验结果表明，活性炭生物转盘对COD的去除效果好于其他两种转盘。在进水COD为600mg／L、水力停留时间为6h、盘片转速为4r／min的条件下，活性炭生物转盘对COD的去除率可达71．3％。此外，活性炭生物转盘还有较强的耐有机负荷冲击能力。在废水处理过程中，活性炭仅在挂膜的前7天起吸附作用，挂膜成功后生物降解起主导作用。     

Effect of Sequential Mixing and Compounding Conditions on Cellulose Acetate/Layered Silicate Nanocomposites

Injection molded nanocomposites have been successfully fabricated from cellulose acetate (CA), eco-friendly triethyl citrate (TEC) plasticizer, and organically modified clay with and without maleic anhydride grafted cellulose acetate butyrate (CAB-g-MA) as a compatibilizer. The effects of processing conditions such as mixing methods, pre-plasticizing times, extruder retention times (RT) and addition of compatibilizer on the performance of these nanocomposites have been evaluated. The cellulosic plastic with CA/TEC (80/20 wt%) was used as the polymer matrix for nanocomposite fabrication. The morphologies of these nanocomposites were evaluated through X-ray diffraction (XRD) and transmission electron microscopy (TEM) studies. The mechanical properties of the nanocomposites were measured and have been correlated with the XRD and TEM observations. From all of the sequential mixing methods used, powder–powder mixing leads to the most transparent nanocomposites. Cellulosic plastic-based nanocomposites obtained using increased pre-plasticizing times and RT showed better exfoliated structures. In the system containing compatibilizer, the minimum retention time required for obtaining almost completely exfoliated hybrid nanocomposites was shorter than in the system without compatibilizer.     

Sex pheromones and their potential role in the evolution of reproductive isolation in small ermine moths (Yponomeutidae)

Summary Sex pheromone communication in the nine European species of small ermine moths (Yponomeuta) is reviewed in regard to the potential role of pheromones in the speciation process. Six of the nine species studied (viz.,Y. evonymellus, Y. cagnagellus, Y. padellus, Y. irrorellus, Y. plumbellus, andY. vigintipunctatus) use a mixture of (E)-11-and (Z)-11-tetradecenyl acetate in different ratios as primary pheromone components, with combinations of tetradecyl acetate, (Z)-9-tetradecenyl acetate, (Z)-11-hexadecenyl acetate and the corresponding alcohols of the acetates as additional pheromone components. Analysis of (Z)- to (E)-11-tetradecenyl acetate ratios produced by individual females of these species demonstrated significant variation among females of all species. However, the ranges of ratios produced byY. cagnagellus, Y. irrorellus, andY. plumbellus, sharing the same host-plant species, spindle tree, did not overlap. Niche separation of all six species mentioned required consideration of at least one additional pheromone component or of temporal aspects. The remaining three species,i.e. Y. malinellus, Y. mahalebellus andY. rorellus, have pheromones that differ qualitatively.Biosynthetic routes to the pheromone components identified are proposed on the basis of fatty acid pheromone precursors found in the pheromone glands. A phylogenetic tree for the genus is constructed based on allozyme frequency data and changes in pheromone composition are superimposed on this tree. We suggest that the ancestral ermine moth pheromone is a mixture of (Z)-11- and (E)-11-tetradecenyl acetate and the corresponding alcohols, and a scenario of how present-day patterns evolved is outlined. The pheromone differences among the three species using spindle tree as their host-plant might have evolved throughreproductive character displacement upon secondary contact between populations that had already diverged genetically in allopatry. Pheromone differences within the so-calledpadellus-complex (includingY. cagnagellus, Y. mahalebellus, Y. malinellus, Y. padellus, andY. rorellus) in which species might have originated sympatrically, may have evolved byreinforcing selection as these species still hybridise and produce viable offspring when confined in cages. The role of pheromones in reproductive isolation amongYponomeuta species is emphasised by (1) the function of pheromone components of some of the species as behavioural antagonists to other species, (2) the cross-attraction under experimental conditions between allochronic species with similar pheromones, and (3) the formation of hybrids in the laboratory between species that are isolated in nature by pheromone differences.