林檎叶防腐保鲜成分微波提取工艺的优化研究

在林檎叶天然防腐保鲜成分微波辅助浸提工艺中通过均匀试验设计构建模型,运用Excel中回归分析工具得到回归方程。试验中所选因素对微波辅助提取的影响顺序为:微波功率>液料比>浸提次数>微波时间。确定林檎叶防腐保鲜成分提取最优工艺条件为:微波时间1min,微波功率700W,液料比61.62∶1,浸提次数3.51。对林檎叶防腐保鲜成分中的活性成分进行化学定性分析,其中含有黄酮类化合物、多元酚类及皂甙等活性物质。     

马占相思树皮中原花色素提取工艺及其生物活性的研究

通过正交试验优化了马占相思树皮中原花色素的3种提取方法的最佳提取工艺条件。结果显示,传统溶剂提取法的最佳工艺为：60%乙醇、70℃、70 min、料液比1∶18（g∶mL,下同）,原花色素得率为7.42%;微波辅助提取法的最佳工艺条件为：60%乙醇、微波功率200 W、微波时间8 min、料液比1∶18,得率为7.05%;超声波辅助提取法的最佳工艺为：70%乙醇、超声波温度50℃、超声波时间50 min、料液比为1∶16,得率为8.57%。超声波辅助提取法效果最好,浸提温度低,得率高。进一步对超声波提取物不同溶剂萃取物的体外抗氧化活性和抗肿瘤活性进行了研究。结果表明,乙酸乙酯萃取物对DPPH·清除效果最好,其半数抑制浓度（IC₅₀）为17.94 mg/L,低于对照样维生素C（Vc）的IC₅₀值;乙酸乙酯萃取物对人肝癌细胞Bel-7404具有明显的抑制效果,IC₅₀值为4.86 mg/L,与抗肿瘤药依托泊苷效果相当。     

肉桂水溶性多糖提取工艺的研究

在肉桂化学成分的研究中,对肉桂多糖成分的研究非常不全面,多糖提取工艺的研究更是鲜有报道。本文研究了肉桂多糖的直接浸提和微波辅助提取两种方法的最佳提取条件。微波辅助提取的最佳条件为:料液比1∶8,微波时间25 min,微波功率350W,提取次数2次。直接浸提的最佳条件为:料液比1∶10,浸提2.5 h,浸提温度80℃,浸提次数3次。通过对比可知,在实验室进行小规模提取时,微波辅助提取在料液比、提取时间和提取次数上有较大优势,但在规模化生产中,直接浸提法则在处理量方面优势明显。     

超声波辅助提取花生粕中花生衣红色素

以花生粕为原料,采用超声波辅助甲醇溶剂法提取花生红衣色素。研究了超声波处理时间、超声波频率、温度、料液比四个影响因素,采用单因素实验法和L_9(3~4)正交表进行实验,以花生衣红色素的吸光度大小来判断提取效果。实验结果表明:该方法的最佳工艺条件为超声时间60min,超声频率35.4k Hz,超声温度50℃,料液比1∶30,且此条件下的提取率高达为8.71%。     

热水法、微波辅助法及超声辅助法提取桔梗多糖的比较研究

以桔梗多糖为研究对象,采用单因素分组实验法对桔梗多糖提取工艺(热水法、微波辅助提取法及超声辅助提取法)进行了初步研究,比较了料液比、温度、提取时间、微波功率、粒度等因素对多糖提取率的影响。实验确定了三种方法的最佳工艺条件,三种方法相比,微波辅助提取时间最短且多糖提取率最高,其最佳工艺条件为:微波功率250 W,微波时间4 min,粒度60目,料液比1∶40。     

不同提取方法对竹屑多糖提取得率影响的研究

采用水提法、微波辅助提取法、超声波提取法三种方法对竹屑多糖进行提取得率工艺研究。通过实验确定每种方法对竹屑多糖得率的最佳工艺条件,结果如下:水提法的优化工艺条件是:料液比1∶15,温度85℃,提取时间2.5 h,此条件下,竹屑多糖的得率可以达到2.278 mg·g~(-1);超声波提取法的优化工艺条件是:料液比1∶20,时间30 min,温度65℃,功率为总超声功率的60%(即180 W),此条件下,竹屑多糖的得率可以达到1.484 mg·g~(-1);微波提取法的优化工艺条件为:料液比为1∶12,功率为700 W,时间为8 min,竹屑多糖的得率可以达到2.026 mg·g~(-1),并对三种方法进行了分析说明。     

酸浆籽油高速匀质—微波辅助提取工艺及其抗氧化活性研究

目的:优选酸浆籽油高速匀质-微波辅助提取工艺及其抗氧化活性研究。方法:以酸浆籽出油率为考察指标,采用单因素法筛选液料比、匀质速度、匀质时间、微波温度、微波功率、微波时间等提取参数,将优选出的参数进行三批工艺验证;以DPPH清除率为指标,以橄榄油为对照,对其进行抗氧化活性研究。结果:优选的酸浆籽油提取工艺参数为液料比为10∶1、匀质速度1200 rpm、匀质时间60 s、微波温度40℃、微波功率500 w、微波时间40 min;通过三批验证,酸浆籽油高速匀质-微波辅助法平均提取率为40.48%,RSD为0.33%,比单一高速匀质提取法(30.24%)、微波辅助提取法(31.55%)提取率更高;酸浆籽油清除DPPH自由基的IC50值为(21.67±0.23)mg/mL。结论:优选的酸浆籽油高速匀质-微波辅助提取工艺合理可行,酸浆籽油具有较好的抗氧化活性。     

微波辅助提取黔产党参多糖及其含量分析

采用微波辅助法对黔产党参进行了多糖提取,从时间、温度、料液比和功率4个因素对多糖得率进行了考察。结果表明,对党参多糖得率影响较大的因素是微波时间和温度,料液比和微波功率对党参多糖提取率无明显影响;最佳提取工艺条件为：提取温度为70℃,微波辐射功率为100 W,料液比为1∶30 g/mL,提取时间为8 min。采用此工艺对毕节市野生党参和铜仁市引种种植党参多糖含量测定分析发现,种植党参与野生党参多糖含量存在一定差异。     

微波法提取竹叶中抗氧化物质的工艺探讨

以竹叶为原料,采用回流提取法、沸水浴提取法、超声波提取法、微波提取法提取其抗氧化性成分,通过测定吸光度利用Fenton反应比较对羟自由基的清除率,用正交实验对提取竹叶的工艺条件进行优化,结果表明:微波提取法效果较好;以60%的乙醇为提取剂,固液比为1g∶15mL,微波火力为60W,提取时间为20s时清除率最高。     

微波辅助棉花秸秆稀酸水解糖化工艺研究

采用微波辅助稀酸法对棉花秸秆进行水解糖化。探索了微波辐射温度、微波辐射时间、料液比及硫酸浓度对秸秆水解糖化效果的影响。结果表明,微波辅助棉花秸秆稀酸水解糖化的最佳糖化工艺条件为:微波辐射温度80℃,微波辐射时间50min,料液比1∶16g/mL,硫酸浓度3.0%。各影响因素对还原糖收率的影响顺序为:料液比微波辐射温度硫酸浓度微波辐射时间。在最佳糖化工艺条件下,还原糖收率为3.17%。     

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.     

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.     

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。     

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。     

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.     

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.     

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.