江门市农田土壤蔬菜重金属污染调查分析

土壤污染具有一定的地域性,调查江门地区的土壤和蔬菜中的污染情况,科学指导菜农对蔬菜的种植。采用直接在本地采集土壤和蔬菜作为样品的方法,利用火焰-原子吸收分光光度法检测Cd、Cr和Pb三种重金属含量。结果表明:该地区的土壤中Cd、Cr和Pb的大部分检测结果都符合国家标准,只有镉测定项目的两个结果的污染指数污染(Pi)值大于1,有轻微污染的情况;在四种菜叶类蔬菜中,菜心的重金属含量最低,都没有超出国家一级标准的规定含量,而西洋菜平均含量恰好相反,三种重金属浓度都偏高,对。     

工业废水重金属在线监测技术对比研究

重金属监测仪是对工业废水中重金属监测的仪器设备,根据检测原理包括原子吸收光谱法、原子发射光谱法、原子荧光光谱法、电感耦合等离子体质谱法以及分光光度计法、化学显色法、微生物法等,在监测精度上不同原理的监测仪器存在一定差异,对在线自动监测仪器中,分光光度法及伏安溶出法结果进行了分析比较,探讨了废水重金属监测使用过程中应注意的问题。结果可知,显色反应分光光度法更适用于高浓度下的重金属检测。而原子吸收分光光度法检测适用于低浓度下的重金属检测,伏安溶出法较分光光度法的准确性更高。     

原子吸收分光光度法测工业废水中重金属的含量

用火焰原子吸收分光光度法检测太原市排入汾河一个支流的工业废水中重金属镉、铬、铅、铜、镍的含量,测定结果发现除了镍外,其它金属含量均超过国家规定的最高容许排放浓度。     

卷烟中有害重金属含量的测定

实验用用原子吸收分光光度法测定市售香烟中的三种有害重金属的含量。样品用马弗炉进行灰化处理后,再用少量浓盐酸处理,进行二次灰化,灰化完全后用浓硝酸处理得到澄清溶液,用1%体积分数的硝酸定容,用原子吸收分光光度法测定样品中几种重金属的含量。该方法简单快捷有效,灵敏度高,干扰少,回收率达到95%以上,相对误差小,对实验样品的测定结果满意。实验数据表明所测市售香烟的烟叶中都不同程度的含有有害重金属元素。     

莲花山矿山土壤重金属污染初步调查

通过运用原子吸收分光光度法、原子荧光光度法对莲花山矿区废弃地典型重金属污染区的土壤进行研究。从所调查的矿区9种植物根际土壤对Cd、As、Pb、Cu、Ni 5种重金属进行检测,分析得到该钨矿区植物土的特性,从数据显示As、Cd、Pb、Cu含量都超标,只有Ni不超标,超标的倍数最大的是As元素的含量。从检测结果可以得出,莲花山矿山的土壤重金属污染特性主要表现在As,Cd 2种元素上。     

双硫腙萃取分光光度法测定色漆涂料中的铅

以双硫腙的1,1,1三-氯乙烷溶液从试液中萃取铅,采用分光光度法检测色漆涂料中铅的含量,该方法选择性好,灵敏度、准确度高,重现性好。具有很好的适用性,可以用于监测色漆涂料中的有害重金属铅的含量。     

碘量法和分光光度法测定萝卜中维生素C含量的比较研究

采用碘量法、分光光度法两种测定方法,分别对白萝卜中的维生素C含量进行测定。碘量法测得100.0g白萝卜中含有12.4mg维生素C,加标回收率为95.53%;分光光度法测得100.0 g白萝卜中含有14.9mg维生素C,加标回收率为99.87%。实验表明,分光光度法准确度更高,适合蔬菜中维生素C含量的测定。     

农用地土壤中重金属含量测定及原因探究

农用地作为粮食的生产来源,土壤中由于工业生产所残留的重金属对农作物生长和人民健康都有着极大的影响。因此,对土壤重金属含量的检测,是保证粮食安全和人民健康的坚实防线。土壤中重金属含量的检测方法有色谱分析法、原子光谱分析法、电化学分析法、分光光度法。选用具有检测限低、检测范围广等特点的电感耦合等离子体-原子发射光谱法对苏南某区域的农用地进行铜、铅、铬、锌、镍、镉含量的检测,并对污染物的来源进行分析。本研究为土壤中重金属离子含量的检测提供方法参考,同时为提高土壤质量、保证国民健康提供一定保障。     

亚单位流感疫苗中裂解剂壬苯醇醚-9含量两种检测方法的比较

目的比较高效液相色谱法(HPLC)和紫外分光光度法检测亚单位流感疫苗中裂解剂壬苯醇醚-9含量的效果。方法分别采用HPLC法和紫外分光度法检测亚单位流感疫苗中间体和成品中壬苯醇醚-9的含量,并取中间体进行SDS-PAGE分析。结果紫外分光光度法测定亚单位流感疫苗成品和中间体的壬苯醇醚-9含量比HPLC法高10%以上,测定中间体3壬苯醇醚-9含量的结果差异更显著;SDS-PAGE分析显示中间体1、2、3的核蛋白(NP)含量差异显著,大多数存在于中间体3中。结论 HPLC法可代替紫外分光光度法检测亚单位流感疫苗中裂解剂壬苯醇醚-9的含量。     

石墨炉原子吸收光谱法测量飞剑潭水库中镉的含量

本文通过石墨炉原子吸收分光光度法测定飞剑潭水库中重金属镉的含量,选取水库库头、库尾和库中三各断面。方法简单快速,结果令人满意。     

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.     

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.     

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。     

Methyl 2,4,6-decatrienoates Attract Stink Bugs and Tachinid Parasitoids

Halyomorpha halys (Stål) (Pentatomidae), called the brown marmorated stink bug (BMSB), is a newly invasive species in the eastern USA that is rapidly spreading from the original point of establishment in Allentown, PA. In its native range, the BMSB is reportedly attracted to methyl (E,E,Z)-2,4,6-decatrienoate, the male-produced pheromone of another pentatomid common in eastern Asia, Plautia stali Scott. In North America, Thyanta spp. are the only pentatomids known to produce methyl 2,4,6-decatrienoate [the (E,Z,Z)-isomer] as part of their pheromones. Methyl 2,4,6-decatrienoates were field-tested in Maryland to monitor the spread of the BMSB and to explore the possibility that Thyanta spp. are an alternate host for parasitic tachinid flies that use stink bug pheromones as host-finding kairomones. Here we report the first captures of adult and nymph BMSBs in traps baited with methyl (E,E,Z)-2,4,6-decatrienoate in central Maryland and present data verifying that the tachinid, Euclytia flava (Townsend), exploits methyl (E,Z,Z)-2,4,6-decatrienoate as a kairomone. We also report the unexpected finding that various isomers of methyl 2,4,6-decatrienoate attract Acrosternum hilare (Say), although this bug apparently does not produce methyl decatrienoates. Other stink bugs and tachinids native to North America were also attracted to methyl 2,4,6-decatrienoates. These data indicate there are Heteroptera in North America in addition to Thyanta spp. that probably use methyl 2,4,6-decatrienoates as pheromones. The evidence that some pentatomids exploit the pheromones of other true bugs as kairomones to find food or to congregate as a passive defense against tachinid parasitism is discussed.