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%。     

桃叶中黄酮的提取及测定研究

探讨了桃树叶中黄酮的提取方法,研究了溶剂浸提温度、时间、固液比、乙醇浓度,超声波或微波辅助等对桃叶中黄酮提取效果的影响。研究结果表明:溶剂浸提中,影响因素依次为:料液比乙醇浓度浸提温度水浴时间;超声波辅助提取中则为乙醇浓度料液比浸提温度超声时间;微波提取中则又为微波时间微波功率料液比乙醇浓度。用70%乙醇作为浸提溶剂,料液比1∶25,温度控制在30℃,1次浸提40 min,桃叶黄酮提取率1.81%;采用超声波辅助提取,料液比为1∶30,浸提温度控制在50℃,提取30 min,用70%乙醇提取桃叶黄酮,提取率最高达3.98%;使用微波辅助提取时,料液比1∶30,微波功率控制在200 W,用60%乙醇提取30 s,则黄酮提取率3.92%。由此可见,纯粹用溶剂提取,提取率较低,不到2%,采用超声波或微波辅助提取,可达近4.0%。     

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。     

超声波强化提取荠菜中总生物碱的研究

采用超声波辅助提取法提取荠菜中总生物碱,考察了提取剂、料液比、提取时间、提取温度、超声波功率对生物碱提取率的影响.正交实验结果表明超声法的最佳提取条件为:乙醇体积分数为70%,料液比为1∶10,提取时间10 min,提取温度50℃,功率160 W.     

不同产地普洱生茶中黄酮含量的区别研究

通过单因素实验研究了乙醇浓度、料液比、超声波功率、提取时间对普洱生茶中总黄酮提取效果的影响,再利用正交实验法优化最佳提取工艺条件。结果表明,对普洱生茶中总黄酮的提取影响的大小次序为超声功率料液比乙醇浓度提取时间,最佳提取工艺为:乙醇浓度65%,料液比1∶75,超声功率270 W,提取时间50 min。并在该最佳提取工艺条件下对不同产地普洱生茶中总黄酮的含量进行了研究。     

超声波法提取淫羊藿中淫羊藿苷工艺研究

对超声波辅助提取淫羊藿中淫羊藿苷进行研究,以淫羊藿苷为考察目标,系统考察了超声波频率、乙醇浓度、超声提取时间、料液比四个因素对提取效果的影响。通过正交实验初步确定最佳提取工艺条件为:90%乙醇,超声波功率900 W,提取时间60 min,料液比1∶20。     

超声波法提取香樟果中总黄酮的研究

利用超声波辅助提取了香樟果中的黄酮类化合物。通过单因素和正交实验研究了乙醇体积分数、超声波时间、超声波功率、温度及料液比对黄酮类化合物提取率的影响。结果表明:乙醇的体积分数为40%,温度为50℃,超声波功率为300 W,液料比为1∶20,时间为0.5 h的条件下提取效果最佳。在最优化条件下测得总黄酮的提取率可达到2.504%。     

何首乌中二苯乙烯苷类物质的超声波提取工艺优化

采用超声波辅助乙醇提取何首乌中二苯乙烯苷类物质,考察了乙醇浓度、料液比、提取温度、提取时间和提取功率对提取率的影响。结果表明,提取最佳工艺条件为:乙醇浓度60%,料液比1∶25 g/m L,提取温度65℃,提取时间1.5 h和提取功率800 W。在此条件下,二苯乙烯苷类物质的提取率达7.19%。     

何首乌中二苯乙烯苷类物质的超声波提取工艺优化

采用超声波辅助乙醇提取何首乌中二苯乙烯苷类物质,考察了乙醇浓度、料液比、提取温度、提取时间和提取功率对提取率的影响。结果表明,提取最佳工艺条件为:乙醇浓度60%,料液比1∶25 g/m L,提取温度65℃,提取时间1.5 h和提取功率800 W。在此条件下,二苯乙烯苷类物质的提取率达7.19%。     

红景天中黄酮类化合物的提取及抗氧化性研究

利用超声波辅助提取红景天中黄酮类化合物,采用单因素和正交实验研究了料液比、乙醇浓度、超声波功率、超声波时间、超声波温度对黄酮类化合物提取率的影响。结果表明,液料比为1∶35,乙醇的浓度为40%,超声波功率为280 W,超声波时间为40 min的条件下提取效果最佳。在最优化条件下测得总黄酮的提取率可达到17.08%,并测定黄酮类化合物对羟基自由基的消除能力。     

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.     

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.     

2007～2008年世界塑料工业进展

收集了2007年7月～2008年6月世界塑料工业的相关资料,介绍了2007～2008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、不饱和聚酯树脂、环氧树脂)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.     

2005～2006年国外塑料工业进展

收集了2005年7月～2006年6月国外塑料工业的相关资料,介绍了2005—2006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生产量以及各国塑料制品的进出口情况。作为对比,介绍了中国塑料的生产情况。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（聚酰胺、聚碳酸酯、聚甲醛、热塑性聚酯、聚苯醚）、通用热固性树脂（酚醛、聚氨酯、不饱和树脂、环氧树脂）、特种工程塑料（聚苯硫醚、液晶聚合物、聚醚醚酮）的品种顺序,对树脂的产量、消费量、供需状况及合成工艺、产品开发、树脂品种的延伸及应用的扩展作了详细的介绍。