N、P共掺杂莲藕生物碳材料用于芦丁的电化学传感

以莲藕为生物质原料、聚磷酸铵(APP)为氮磷掺杂剂制备了一种N、P共掺杂生物质碳材料，采用SEM、TGA、XRD、XPS和FTIR对材料的结构、形貌和元素组成进行了表征，并以该碳材料修饰玻碳电极，构建了一种检测芦丁的电化学传感器。采用电化学阻抗谱、循环伏安法和差分脉冲伏安法考察了传感器的电化学性能及芦丁在不同电极上的电化学行为。结果表明，在莲藕与APP质量比为1∶1、热解温度为800℃条件下，制备的热解碳材料修饰电极对芦丁的检测效果最好。在最优化条件下，芦丁浓度与该修饰电极的响应电流呈线性关系，检出范围为0.01～10μmol/L，检出限为1.19×10^–2μmol/L(信噪比=3)。此外，该修饰电极对双黄连口服液和健康人尿样中芦丁的测定效果良好。     

一步电沉积制备多孔石墨烯/金纳米复合材料修饰电极测定芦丁

在玻碳电极(GCE)上覆盖一层多孔石墨烯/金纳米复合材料,制备了一种简单、低成本、高灵敏度的电化学传感器应用于芦丁的测定。考察了沉积圈数、缓冲液pH值对芦丁反应的影响。采用差分脉冲伏安法在优化条件下,芦丁浓度在1nmol/L～1μmol/L和1μmol/L～10μmol/L范围内与其氧化峰电流呈良好的线性关系,最低检出限为0.35nmol/L。     

基于葡萄糖酸锌衍生碳源制备同时检测邻/对苯二酚的电化学传感器

为实现邻苯二酚(HQ)和对苯二酚(CA)的快速、灵敏检测,以NaC1作为模板、葡萄糖酸锌(sodium gluconate)为碳源,通过溶解-重结晶制备碳前驱体,同时热解制备多孔碳材料(ZGDPC)并将其用于构建电化学传感器ZGDPC/GCE.使用扫描电子显微镜(SEM)、X射线粉末衍射(XRD)及比表面积分析仪分别对其形貌和结构进行了表征,然后通过差分脉冲伏安法(DPV)考察了ZGDPC/GCE表面HQ和CA的电化学行为.优化条件下,HQ的线性检出范围为0～25 μmol/L,检出限为0.124 μmol/L,CA的线性检出范围为0～30 μmol/L,检出限为0.213 μmol/L.该传感器对实际水样中HQ和CA的回收率为95.6％～102.3％.以上结果表明,基于该电化学传感器能实现实际样品中对HQ和CA的同时检测.     

基于纳米铜-碳纳米纤维复合材料的电化学传感器检测芦丁

采用化学还原法制备了纳米铜-碳纳米纤维复合材料(CuNPs-CNFs),将其修饰在玻碳电极表面制备了一种检测芦丁的电化学传感器。在铁氰化钾-亚铁氰化钾体系中,采用电化学阻抗法和循环伏安法考察了传感器的电化学响应,研究了传感器的电化学性能;采用扫描电镜研究了传感器的表面形貌。在0.067 mol/L Na_2HPO_4-NaH_2PO_4(pH=7.0)缓冲溶液中,采用循环伏安法研究了芦丁在传感器上的电化学行为,结果表明,传感器对芦丁的氧化还原反应有较好的电催化作用。在优化实验条件下,用微分脉冲伏安法测得芦丁的还原峰电流与其在5.0×10~(-9)～5.0×10~(-6) mol/L浓度范围内呈线性关系,检出限为3.0×10~(-9) mol/L,该传感器具有较好的重现性和稳定性,可用于芦丁片剂和槐米中芦丁含量的测定。     

Hf-ZnO酪氨酸酶生物传感器检测邻苯二酚

以四氯化铪(HfCl4)和硝酸锌为原料，通过水热法制得Hf掺杂氧化锌纳米材料(Hf-ZnO)，并将Hf-ZnO、酪氨酸酶(Tyr)和壳聚糖(CS)修饰在玻碳电极(GCE)上,制得Tyr/Hf-ZnO/CS/GCE生物电极。利用FESEM、DLS、XRD和XPS对Hf-ZnO的结构和性能进行表征。采用循环伏安伏安法(CV)和计时电流法(IT)对Tyr/Hf-ZnO/CS/GCE电极进行电化学测试。结果表明，Tyr/Hf-ZnO/CS/GCE电极在pH 5和-50 mV的低电势下对邻苯二酚有最佳检测能力，对邻苯二酚检测的线性范围是0.5~47 μmol/L，灵敏度为195 μA/(mmol/L)，检测限是0.1215 μmol/L(S/N=3)。此外，该生物电极的稳定性和重复性好，可有效避免尿素、多巴胺、抗坏血酸等与邻苯二酚电活性相近物质的干扰。     

柚皮热解炭应用于对\邻苯二酚电化学传感器

分别以氨水、NaOH和KOH为活化剂对柚皮进行活化,然后通过一步热解法制备了生物炭材料.与其他活化剂处理得到的生物炭相比,经KOH活化处理后制得的生物炭孔道分布最为丰富,同时表现出最大的比表面积.通过滴涂法将该类生物炭分别修饰在玻碳电极表面,在磷酸盐缓冲液(PBS,pH=7.0)中用微分脉冲伏安法(DPV)考察了对苯二酚(HQ)和邻苯二酚(CA)在不同电极上的电化学行为.结果表明,经KOH活化后制得的生物炭修饰电极对HQ和CA同时检测效果最佳.在最优条件下和0.5～100μmol/L浓度范围内时,HQ和CA对该传感器的响应电流随浓度线性增大,检出限分别低至0.023和0.040μmol/L.同时,该传感器具有良好的稳定性并可应用于HQ和CA的实际样品检测.     

纳米氧化铜/石墨烯修饰电极的制备及对H_2O_2的检测

采用电化学方法在玻碳电极上修饰石墨烯及纳米氧化铜,制备了纳米氧化铜/石墨烯修饰电极(nanoCuO/ERGO/GCE)。研究了纳米氧化铜/石墨烯修饰电极的电化学性质。该修饰电极在氢氧化钠溶液中,低电位下(0.08V)可催化氧化过氧化氢。在2.3×10-5~3.0×10-3mol/L和3.0×10-3~8.3×10-3mol/L浓度范围内,过氧化氢的响应电流与浓度呈良好的线性关系,线性相关系数分别为0.9943和0.9972,检测限为6.96×10-6mol/L(三倍噪音法)。     

基于聚L-精氨酸修饰玻碳电极的抗坏血酸电化学传感器的研究

研究了电化学方法制备聚L-精氨酸修饰电活化玻碳电极(PLA/GCME)即抗坏血酸电化学传感器及抗坏血酸(AA)在该传感器上的电化学行为。结果表明,传感器对AA具有较好的催化作用。AA的氧化峰电流与其浓度在1.0×10-2~1.0×10-5mol/L范围内呈现良好的线性关系,检出限为6.71×10-6mol/L。传感器具有良好的重现性和稳定性。该方法用于实际样品的测定,回收率在98.3%~104.1%之间。     

螺旋霉素的电化学检测研究

通过恒电位还原氧化石墨烯的方法制备电化学还原氧化石墨烯修饰电极(rGO/GCE),再结合浸渍法制备出电化学还原氧化石墨烯纳米银复合修饰电极(rGO-AgNPs/GCE)。考察了螺旋霉素(SPY)在rGO-AgNPs/GCE上的电化学响应情况，并对修饰量、电还原时间、浸渍时间、支持电解质种类及酸碱度等实验条件进行优化。结果显示，在2.0×10^-6～1.0×10^-4 mol/L浓度范围内，SPY氧化峰电流与其浓度呈显著的线性关系，线性方程为I_p=0.528 5c+26.085,r=0.997 3,检测下限为4.0×10^-7 mol/L。稳定性、可重复性和回收率实验取得令人满意的结果。     

纳米银石墨烯多壁碳纳米管复合修饰电极检测双酚A

利用浸渍法和电化学还原法制备了纳米银石墨烯多壁碳纳米管复合修饰电极(Ag NPs/GR/MWCNTs/GCE),采用循环伏安法(CV)表征了复合电极的电化学性能,研究了双酚A(BPA)在Ag NPs/GR/MWCNTs/GCE上的电化学行为,并在此基础上使用差分脉冲伏安法(DPV)探讨了Ag NPs/GR/MWCNTs/GCE检测BPA的可行性。结果表明,在8.0×10~(-6)～1.0×10~(-4)mol/L范围内,BPA的电化学检测峰电流值与其浓度呈明显的线性关系,线性方程为I_p=1.076 1C-5.153 6,相关系数r=0.999 4。研究表明,Ag NPs/GR/MWCNTs/GCE可用于BPA的电化学检测。     

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.     

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.     

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.     

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.     

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。