醇醚糖苷厌氧生物降解性能及降解机理研究

参考GB/T 27857-2011有机物厌氧降解试验方法,在实验室条件下模拟厌氧环境,采用蒽酮法和TOC法分别研究了醇醚糖苷(AEG)的初级和最终生物降解性能。结果表明,即使AEG的起始质量浓度达到100 mg/L,其初级厌氧生物降解率仍然能够达到90%以上;当起始质量浓度为40 mg/L时,其最终厌氧生物降解率为88.5%。最后采用气-质联用仪对AEG的厌氧生物降解机理进行探讨发现:AEG首先经历糖苷醚键断裂,生成葡萄糖和AEO;之后AEO从末端EO链开始降解形成醇,最后转化为CO_2、CH_4和水等。     

驯化污泥对厌氧生物降解2,4-二氯酚的影响

以2,4-二氯酚(2,4-DCP)为目标污染物,考察葡萄糖共基质条件下厌氧污泥驯化过程中目标物的生物降解以及驯化污泥对2,4-DCP降解效果的影响.结果表明:厌氧污泥具有降解2,4-DCP的潜力,连续驯化2个月其对污染物的降解能力逐步增强.2,4,6-TCP(2,4,5-三氯酚)与2,4-DCP长期共存可加快厌氧污泥对...     

吸附-生物降解法处理含挥发性有机物废水

采用吸附-生物降解法处理含碳氢溶剂挥发性有机物(VOCs)的水洗废水,研究了废水中挥发性有机成分的非稳性,考察了2种活性污泥(厌氧、好氧污泥)对废水中挥发性有机物的吸附性能,探讨了厌氧-好氧组合工艺对水洗废水的降解效能,分析了处理工艺的运行效果.结果表明,水洗废水中的VOCs易再次挥发,曝气状态下VOCs的最大挥发率为...     

城市污泥厌氧法处理聚乙二醇废水

在厌氧条件下,考察驯化后的城市污泥对聚乙二醇2000(PEG2000)的降解效果。结果表明,驯化后的城市污泥经厌氧反应后形态发生变化,孔隙变大,厌氧菌以菌胶团的形式存在于污泥中。在PEG初始质量浓度为4.0 g/L,总有机碳(TOC)为1 650 mg/L,38℃的恒温厌氧降解条件下,系统运行前5 d,PEG2000降解率快于TOC降解率,通过液质联用(LC-MS)分析发现,PEG2000在降解初始阶段断裂为分子质量较低的物质,厌氧反应10 d后,低分子质量的物质进一步氧化降解,TOC和PEG2000降解率均高于90%。     

酸性染料黑10B的生物降解特性研究

在好氧、厌氧和兼性交替条件下,采用活性污泥系统生物处理酸性染料,研究染料酸性黑10B在有氧或者厌氧状态下的生物降解特性以及在不同染料浓度和不同生物化学需氧量(COD)条件下对其降解特性的影响,并进行全波段扫描和气相色谱-质谱联用(GC-MS),初步探讨了该染料的生物降解过程。结果表明,染料黑10B在厌氧条件下降解效率最高,兼性条件下次之,好氧条件下最低。随着染料黑10B浓度的增加,反应器中COD的去除率逐渐降低。而碳源的投加量也对酸性黑10B的生物降解起到重要的作用。全波段扫描和GC-MS测定结果显示,染料黑10B经过生物降解作用后,发色基团得到降解,染料黑10B生物降解中间产物有苯胺、对苯二胺、对硝基苯胺,这些中间产物对应的停留时间分别是10.168、15.875、21.747 min。     

2,4,6-三硝基甲苯生物降解研究进展

介绍了降解2,4,6-三硝基甲苯(TNT)的微生物及降解途径.总结了好氧氧化、厌氧还原以及厌氧和好氧过程协同作用降解TNT的代谢途径.指出目前生物法降解TNT存在的关键问题是实际应用中降解效率低,在分子水平上对相关基因、酶进行研究、多种技术的联合和生物法的实际应用是今后生物法研究的重点.     

污泥中邻苯二甲酸酯生物降解性与化学结构的相关性

为预测邻苯二甲酸酯类环境激素的好氧生物降解性,评价其在城市污泥中的滞留情况,应用定量结构-活性关系(QSAR)研究方法,对城市污泥中邻苯二甲酸酯类化合物的好氧生物降解性能与其化学结构间的关系(QSBR)进行了研究。研究表明,污泥中邻苯二甲酸酯类化合物好氧生物降解速率常数随受试物相对分子质量的增大而减少,以分子连接性指数描述的空间结构参数是影响受试物好氧生物降解性能的重要因素。     

污泥热消化试验研究

污泥是污水处理的产物,成分复杂,如果处置不当会引起二次污染。污泥热消化可以使污泥达到稳定化和无害化。实验比较了在不同污泥浓度下,污泥高温好氧消化的效果,并且对污泥高温好氧消化和高温厌氧消化、高温厌氧消化和常温厌氧消化进行了比较,得出结果:低浓度的污泥(含水率约91.5%,VSS=38.6 mg/L)更有利于污泥的高温好氧消化,经过12 d的高温好氧消化,污泥各项指标:COD、VSS的降解率分别达到76.58%和50.2%,热消化中的高温(约50℃)可以去除污泥中的病原菌、病毒等,可以使污泥达到农用的标准;高温好氧消化和高温厌氧消化(都在低浓度污泥条件下)均可以使污泥达到稳定化,但经高温厌氧消化后的污泥有臭味;高温厌氧消化无论是在杀菌、杀病毒方面还是在产甲烷和氢气的速率方面等都要优于常温厌氧消化。     

基于EGSB反应器的不同接种污泥启动厌氧氨氧化特性研究

采用两套相同的EGSB反应器，分别接种厌氧颗粒污泥和好氧活性污泥，在温度(35±1)℃、水力停留时间6 h、上升流速为4 m/h的条件下，通过低浓度基质模拟废水进行驯化启动厌氧氨氧化，考察驯化启动厌氧氨氧化反应变化的特性以及基质浓度梯度提升和基质比对驯化系统运行的影响特性。结果表明：接种厌氧颗粒污泥和好氧活性污泥分别经过93 d和63 d后成功驯化启动了厌氧氨氧化，并经过容积TN负荷提升达到1.76 kgN/(m³·d),TN去除率均值分别达到了83%和81%；当进水基质比为1.32时，接种厌氧颗粒污泥组的NH₄⁺-N去除量∶NO₂^--N去除量∶NO₃^--N产生量为1∶1.24∶0.15，低于理论值1∶1.32∶0.26，而接种好氧活性污泥组的为1∶1.33∶0.17接近理论值。     

城市污水处理厂剩余污泥厌氧消化试验研究

探讨了影响污泥厌氧消化的各种因素，包括温度、pH值、污泥投配率、有机负荷等，以期寻找出最佳的污泥厌氧消化条件，获得最高的污泥降解率和最高的产气量；为比较不同停留时间和有机负荷对污泥厌氧消化效率的影响，实验中维持进料含固率不变，探讨相关的污泥厌氧消化效率。     

Sapindaceae,cyanolipids, and bugs

Scentless plant bugs (Heteroptera: Rhopalidae) are so named because adults of the Serinethinae have vestigial metathoracic scent glands. Serinethines are seed predators of Sapindales, especially Sapindaceae that produce toxic cyanolipids. In two serinethine species whose ranges extend into the southern United States,Jadera haematoloma andJ. sanguinolenta, sequestration of host cyanolipids as glucosides renders these gregarious, aposematic insects unpalatable to a variety of predators. The blood glucoside profile and cyanogenesis ofJadera varies depending on the cyanolipid chemistry of hosts, and adults and larvae fed golden rain tree seeds (Koelreuteria paniculata) excrete the volatile lactone, 4-methyl-2(5H)-furanone, to which they are attracted.Jadera fed balloon vine seeds (Cardiospermum spp.) do not excrete the attractive lactone. Loss of the usual heteropteran defensive glands in serinethines may have coevolved with host specificity on toxic plants, and the orientation ofJadera to a volatile excretory product could be an adaptive response to save time.Mention of a commercial product does not consititute an endorsement by the USDA.     

Insect antifeedant properties of anthranoids from the genusVismia

Vismiones and ferruginins, representatives of a new class of lypophilic anthranoids from the genusVismia were found to inhibit feeding in larvae of species ofSpodoptera, Heliothis, and inLocusta migratoria.     

2008～2009年世界塑料工业进展

收集了2008年7月～2009年6月世界塑料工业的相关资料,介绍了2008～2009年国外塑料工业的发展情况,提供了世界塑料产量、消费量及全球各类树脂的需求量及产能情况。按通用热塑性树脂(聚乙烯、聚丙烯、聚苯乙烯、聚氯乙烯、ABS树脂)、工程塑料(尼龙、聚碳酸酯、聚甲醛、热塑性聚酯、聚苯醚)、特种工程塑料(聚苯硫醚、液晶聚合物、聚醚醚酮)、通用热固性树脂(酚醛、聚氨酯、环氧树脂、不饱和聚酯树脂)不同品种的顺序,对树脂的产量、消费量、供需状况及合成工艺、产品应用开发、树脂品种的延伸及应用的进一步扩展等技术作了详细介绍。     

Direct observation of freeze-thaw instability of latex coatings via high pressure freezing and cryogenic SEM

Despite its industrial importance, the subject of freeze-thaw (F/T) stability of latex coatings has not been studied extensively. There is also a lack of fundamental understanding about the process and the mechanisms through which a coating becomes destabilized. High pressure (2100 bar) freezing fixes the state of water-suspended particles of polymer binder and inorganic pigments without the growth of ice crystals during freezing that produce artifacts in direct imaging scanning electron microscopy (SEM) of fracture surfaces of frozen coatings. We show that by incorporating copolymerizable functional monomers, it is possible to achieve F/T stability in polymer latexes and in low-VOC paints, as judged by the microstructures revealed by the cryogenic SEM technique. Particle coalescence as well as pigment segregation in F/T unstable systems are visualized. In order to achieve F/T stability in paints, latex particles must not flocculate and should provide protection to inorganic pigment and extender particles. Because of the unique capabilities of the cryogenic SEM, we are able to separate the effects of freezing and thawing, and study the influence of the rate of freezing and thawing on F/T stability. Destabilization can be caused by either freezing or thawing. A slow freezing process is more detrimental to F/T stability than a fast freezing process; the latter actually preserves suspension stability during freezing. Presented at the 82nd Annual Meeting of the Federation of Societies for Coatings Technology, October 27–29, 2004 in Chicago, IL. Tied for first place in The John A. Gordon Best Paper Competition.     

Ethanol and (−)-α-Pinene: Attractant Kairomones for Bark and Ambrosia Beetles in the Southeastern US

In 2002–2004, we examined the flight responses of 49 species of native and exotic bark and ambrosia beetles (Coleoptera: Scolytidae and Platypodidae) to traps baited with ethanol and/or (−)-α-pinene in the southeastern US. Eight field trials were conducted in mature pine stands in Alabama, Florida, Georgia, North Carolina, and South Carolina. Funnel traps baited with ethanol lures (release rate, about 0.6 g/day at 25–28°C) were attractive to ten species of ambrosia beetles (Ambrosiodmus tachygraphus, Anisandrus sayi, Dryoxylon onoharaensum, Monarthrum mali, Xyleborinus saxesenii, Xyleborus affinis, Xyleborus ferrugineus, Xylosandrus compactus, Xylosandrus crassiusculus, and Xylosandrus germanus) and two species of bark beetles (Cryptocarenus heveae and Hypothenemus sp.). Traps baited with (−)-α-pinene lures (release rate, 2–6 g/day at 25–28°C) were attractive to five bark beetle species (Dendroctonus terebrans, Hylastes porculus, Hylastes salebrosus, Hylastes tenuis, and Ips grandicollis) and one platypodid ambrosia beetle species (Myoplatypus flavicornis). Ethanol enhanced responses of some species (Xyleborus pubescens, H. porculus, H. salebrosus, H. tenuis, and Pityophthorus cariniceps) to traps baited with (−)-α-pinene in some locations. (−)-α-Pinene interrupted the response of some ambrosia beetle species to traps baited with ethanol, but only the response of D. onoharaensum was interrupted consistently at most locations. Of 23 species of ambrosia beetles captured in our field trials, nine were exotic and accounted for 70–97% of total catches of ambrosia beetles. Our results provide support for the continued use of separate traps baited with ethanol alone and ethanol with (−)-α-pinene to detect and monitor common bark and ambrosia beetles from the southeastern region of the US.     

Many Drugs of Abuse May Be Acutely Transformed to Dopamine,Norepinephrine and Epinephrine In Vivo

It is well established that a wide range of drugs of abuse acutely boost the signaling of the sympathetic nervous system and the hypothalamic–pituitary–adrenal (HPA) axis, where norepinephrine and epinephrine are major output molecules. This stimulatory effect is accompanied by such symptoms as elevated heart rate and blood pressure, more rapid breathing, increased body temperature and sweating, and pupillary dilation, as well as the intoxicating or euphoric subjective properties of the drug. While many drugs of abuse are thought to achieve their intoxicating effects by modulating the monoaminergic neurotransmitter systems (i.e., serotonin, norepinephrine, dopamine) by binding to these receptors or otherwise affecting their synaptic signaling, this paper puts forth the hypothesis that many of these drugs are actually acutely converted to catecholamines (dopamine, norepinephrine, epinephrine) in vivo, in addition to transformation to their known metabolites. In this manner, a range of stimulants, opioids, and psychedelics (as well as alcohol) may partially achieve their intoxicating properties, as well as side effects, due to this putative transformation to catecholamines. If this hypothesis is correct, it would alter our understanding of the basic biosynthetic pathways for generating these important signaling molecules, while also modifying our view of the neural substrates underlying substance abuse and dependence, including psychological stress-induced relapse. Importantly, there is a direct way to test the overarching hypothesis: administer (either centrally or peripherally) stable isotope versions of these drugs to model organisms such as rodents (or even to humans) and then use liquid chromatography-mass spectrometry to determine if the labeled drug is converted to labeled catecholamines in brain, blood plasma, or urine samples.