超声波法提取木材中阿拉伯半乳聚糖的工艺参数优化

以兴安落叶松(Larix grneinii Rupr．)木材的加工剩余物为原料，采用超声波法提取阿拉伯半乳聚糖。根据前期单因素试验确定的主要影响因素，采用正交试验研究了不同参数对超声波法提取阿拉伯半乳聚糖提取率的影响，另外组合对试验结果有最大影响的各因素为追加试验的工艺参数。较佳工艺参数为：原料粒度60—80目的兴安落叶松木粉5．0g，超声波功率160W，料液比1：30，提取时间50min，阿拉伯半乳聚糖粗糖收率19．47％。通过红外光谱和紫外光谱分析鉴定其结构。     

超声波提取生姜中姜辣素的工艺研究

采用干生姜粉末为原料,超声波法提取其中姜辣素。从乙醇浓度、温度、时间、固液比及超声功率等单因素方面研究其对提取效果的影响,并用正交试验优化了工艺参数。实验结果表明,较优的提取工艺条件是:60%浓度乙醇;25℃提取温度;10min提取时间;1∶15的固液比,在此条件下姜辣素提取率达到5.14%。     

正交法优选石榴皮中黄酮类化合物的提取工艺

采用正交试验方法研究石榴皮中黄酮的提取工艺,原料为攀枝花大田石榴,以芦丁为标准品,采用分光光度法,以超声波辅助提取,并用提取物得率为考察指标,结果显示乙醇提取法最佳工艺组合为A2B2C2D2,即:超声提取时间30 min、料液比1∶20、乙醇浓度70 %、超声波功率45 W.其中主要因素为超声提取时间.影响最小因素为超声频率.超声提取时间、溶剂倍量因素以及乙醇浓度对总黄酮溶出含量影响极大,应加以控制.     

超声波提取灯笼草中总黄酮的最佳提取条件的研究

本文以灯笼草为原料,研究超声波提取灯笼草总黄酮的最佳工艺。通过单因素试验研究乙醇体积分数、料液比、超声波功率及超声时间对总黄酮提取量的影响。以此为基础,采用正交试验设计,优化超声波提取灯笼草总黄酮工艺条件结果为乙醇浓度为60%,最佳料液比为1︰40,提取温度为50℃,超声波功率为100 W,提取时间30 min为最佳提取条件。黄酮提取率为5.66%。     

正交试验法优选废次烟叶烟碱的超声波提取工艺

以废次烟叶为原料,用正交试验法优化了废次烟叶烟碱的超声波提取工艺,考察了超声时间、温度、乙醇浓度3个因素对烟碱提取量的影响,确定了超声波提取烟碱的最佳工艺为:以乙醇作为提取溶剂,超声时间30min、温度50℃,乙醇浓度80％。在该优化条件下,超声波提取烟碱量为22．7 mg·mL-1。     

肉苁蓉多糖超声波提取工艺条件的优化

多糖是肉苁蓉中的主要成分之一,具有调节免疫活性、抗衰老、抗肿瘤等作用。本实验以内蒙古肉苁蓉为主要原料,先采用单因素试验法分别对影响肉苁蓉多糖提取的主要因素进行分析研究,最后再利用正交试验法优化选取一个最佳的工艺条件。结果表明肉苁蓉多糖超声波提取最佳工艺条件是:提取温度60℃;料水比1∶25;提取时间75 min。此条件下测得肉苁蓉多糖的含量为18. 90%。     

正交实验法优选超声辅助提取稻壳中黄酮的工艺

以稻壳为原料,采用超声波提取法提取稻壳中黄酮。通过单因素试验及正交设计试验,考查了超声温度、乙醇浓度、料液比、超声时间对稻壳黄酮提取得率的影响。结果表明,最优提取工艺条件为超声温度70℃,乙醇浓度50%,料液比1∶50(g∶m L),超声时间20min。此条件下稻壳黄酮提取得率为0.59%。验证试验表明,优化后的提取工艺条件稳定可行。     

银杏叶中有效成分的提取及性质研究

以汉中银杏树叶为原料,采用有机溶剂提取法对银杏叶中黄酮类化合物的提取工艺进行研究,通过单因素实验研究了不同提取温度,提取液浓度,提取次数,超声波对银杏叶中黄酮提取率的影响,其中对其显著地影响因素采用正交试验作以继续探究,得到:在提取温度70℃,提取液浓度为70%,提取次数为3次下为最佳提取条件,并且对黄酮类物质作以性能研究得到:黄酮类物质对绿豆幼苗有壮苗作用。     

响应曲面法优化超声波辅助提取艾叶中总黄酮的工艺研究

以艾叶为原料,采用单因素实验与响应曲面分析法相结合,研究了超声波辅助提取艾叶中总黄酮的影响因素及最佳工艺条件。结果表明,超声波辅助提取艾叶中总黄酮的最佳工艺条件为:乙醇体积分数60%,提取时间60min,液固比为20∶1(mL·g-1),提取温度为40℃,艾叶中总黄酮的提取率为9.15%。与传统法相比,超声波辅助提取法显著提高了艾叶中总黄酮的得率,大大缩短了提取时间,该提取工艺稳定可行,具有明显的优势和很大的应用前景。     

落叶松中二氢槲皮素的提取工艺研究

采用正交试验法研究落叶松中二氢槲皮素的提取工艺。考察了萃取温度、固液比、萃取时间、萃取次数、pH值、沉淀剂用量及乙酸乙酯用量等7个因素对二氢槲皮素提取率的影响。确立了落叶松中二氢槲皮素提取的最佳条件是:萃取温度为80℃,原料与水的固液比为1∶12,萃取时间为20min,萃取次数为3次,pH值为6,沉淀剂A用量为原料质量的30%,V(溶液)∶V(乙酸乙酯)为1∶0.7。提取率为0.29%。     

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.     

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.     

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.     

ICP-MS法测定地球化学样品中As、Cr、Ge、V等18种微量痕量元素的研究

建立了测定地球化学样品中包括As、Cr、Ge、V等18种微量、痕量元素的ICP-MS方法。地化试样用HF-HNO3混酸分解后,以1 1 HNO3溶解干渣。由于制样不使用盐酸,避免了Cl对As、Cr、Ge、V的质谱干扰。用国家一级地球化学标准物质GBW 07309制备溶液优化仪器工作参数,并用于校准。方法测定限(6s)为:0.007~6.4μg/g,精密度(RSD%,n=12)为:29%~9.4%,经过国家一级地球化学标准物质的分析验证,结果与标准值吻合。方法已应用于国土资源调查的试样分析。