超声波提取法对海燕总皂苷提取工艺的研究

采用超声波提取法从海燕中提取总皂苷。在考察单因素影响后,以溶剂浓度、提取时间、料液比、超声波功率及温度建立正交实验。比较超声波提取法与微波提取法和索氏提取法的提取率,结果表明:超声波提取法最优;影响超声波提取法提取率的主要因素为溶剂浓度与料液比,其次是温度和提取时间。超声波提取法提取海燕皂苷工艺的优选方案为:料液比1︰20,乙醇浓度85%,温度70℃,超声功率60 W,提取时间20 min。     

超声波辅助提取黑米色素工艺研究

采用超声波辅助法从黑米粉末中提取黑米色素.通过单因素实验考查了提取温度、提取时间、料液比、超声波功率对色素提取率的影响.在单因素试验基础上,结合正交试验优化提取工艺.实验数据分析得出:提取温度为35℃,提取时间为35 min,料液比为1:6 g/mL,超声波功率为70 W时,黑米色素的提取率最高.     

响应面优化蝙蝠葛根生物碱的提取工艺

为确定从蝙蝠葛根中提取生物碱的最佳工艺,以蝙蝠葛根为材料、乙醇溶液为提取剂,利用超声波辅助提取蝙蝠葛根生物碱。在超声功率175 W的条件下,通过单因素试验考察乙醇浓度、超声温度、超声时间、料液比对超声提取蝙蝠葛生物碱提取量的影响。应用Box-Benhnken中心组合方法进行4因素3水平设计,以蝙蝠葛根生物碱提取量为响应值,采用响应面法优化蝙蝠葛根生物碱的提取工艺。结果表明,超声波辅助提取蝙蝠葛根中生物碱的最佳工艺为料液比1∶40(g/mL)、乙醇浓度70%、超声温度40℃、超声时间2 h,在此工艺条件下,蝙蝠葛根生物碱的提取量为9.067 mg/g。该工艺条件切实可行,可用于控制和预测蝙蝠葛根中生物碱的提取。     

超声波提取山茶花红色素的初步工艺研究

利用超声波技术提取山茶花红色素,通过超声波提取时间、超声波功率、提取温度、料液比、提取次数等单因素实验得到得到山茶花红色素超声波提取的工艺参数为:提取时间40min,提取功率500W,料液比1:12(g/mL),提取温度40℃,提取次数为3次。     

地椒多糖提取工艺研究

主要采用超声波法从地椒中提取多糖,用苯酚-硫酸法测定其含量。通过单因素和正交实验,研究超声波提取时间、料液比、超声功率、超声提取温度四个单因素对地椒多糖提取率的影响,结果表明,影响地椒多糖提取率因素的顺序为:液料比超声提取时间超声提取温度。最终确定超声波法提取地椒中多糖的最佳工艺条件为:超声波提取时间55min、地椒粉1g,乙醇40mL,提取温度45℃,超声功率150 W,在此条件下地椒多糖的提取率为4.13%。     

超声辅助提取柚皮黄酮及其抗氧化性的研究

本论文采用超声波辅助提取柚皮中黄酮类化合物。首先考察超声波的提取时间、乙醇浓度、料液比、提取温度、提取功率五个因素对黄酮类化合物提取率的影响。单因素实验表明,提取时间和提取温度对黄酮类化合物提取率的影响不大,超声波辅助提取柚皮中黄酮的优化工艺条件为:料液比1∶15,乙醇的体积分数为60%,提取功率175 W,与传统工艺相比,超声法有较高提取率。Fenton法表明柚皮中的黄酮具有较强的抗氧化作用。     

响应面法优化超声辅助提取杜仲多糖的工艺研究

采用超声波辅助水提醇沉法提取杜仲粗多糖。以多糖得率为评价指标,考察料液比、提取温度、提取时间和提取功率四个因素水平,采用Box-Behnken法优化提取工艺。结果显示,超声波辅助提取杜仲多糖的最佳工艺条件为料液比1∶31,提取时间为17 min,提取温度为72℃,提取功率为89 W,理论多糖得率为6.19%,在此条件下得到的实际多糖得率为6.28%,相对误差为1.50%。优化的杜仲多糖提取工艺多糖得率高。     

超声提取苦瓜多糖的工艺研究

以苦瓜为原料,研究提取温度、提取时间、超声波功率、料液比对苦瓜多糖提取率的影响。结果表明,在提取温度55℃,提取时间35 min,超声功率350 W,料液比为1∶30(g.mL-1)的条件下,苦瓜多糖提取率可达到13.94%。     

超声波提取无花果皮红色素的研究

利用超声波技术提取无花果皮红色素,通过单因素和正交实验研究了红色素提取的最佳条件,结果表明,影响无花果皮红色素提取的主要因素是超声波功率,其次是超声波提取温度和超声波提取时间,再次是提取料液比。最佳提取条件为:超声波功率350 W,提取温度40℃,提取时间25 min,料液比1∶20(g/mL),收率为10.23%。     

超声波法提取曼陀罗种子总生物碱的工艺优化

采用超声波法对曼陀罗种子总生物碱提取工艺进行优化。采用乙醇为提取溶剂,以提取温度、超声时间和超声功率为考察对象,在单因素优化的基础上设计4因素和3水平正交实验,研究曼陀罗种子总生物碱的最优提取条件。结果表明:超声波法提取曼陀罗种子总生物碱的优化工艺条件为提取剂乙醇浓度85%,提取温度40℃,超声时间20 min,超声功率100 W,在此条件下,曼陀罗种子总生物碱提取得率为0.492%。     

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。