超临界CO_2萃取木香挥发油的研究

采用超临界CO_2流体萃取木香挥发油。探讨了压力、温度、CO_2密度对挥发油收率的影响,研究了萃取的最适宜条件。对水蒸汽蒸馏法与超临界萃取法进行了比较。     

超临界CO2萃取木香挥发油的研究

采用超临界ＣＯ２流体萃取木香挥发油。探讨了压力、温度、ＣＯ２密度对挥发油收率的影响，研究了萃取的最适宜条件。对水蒸汽蒸馏法与超临界萃取法进行了比较。     

超临界CO_2萃取柴胡茎、叶中挥发油的实验研究

采用超临界CO2萃取从柴胡茎、叶中提取挥发油,通过正交实验确定了超临界CO2萃取柴胡挥发油的工艺条件为萃取压力15 MPa,萃取温度55℃,CO2流量20 L/h,在此条件下,挥发油的收率为0.9%,并将所得结果与水蒸气蒸馏法所得的结果进行了比较,超临界CO2萃取的收率明显高于水蒸气蒸馏。     

干姜化学成分提取及其在卷烟中的应用

采用同时蒸馏萃取法与超临界二氧化碳萃取法制备干姜挥发油,应用于卷烟中。研究了同时蒸馏萃取和超临界二氧化碳萃取干姜挥发油的工艺,并对两种干姜挥发油化学成分进行气相色谱-质谱法检测。结论表明,超临界CO_2萃取干姜挥发油化学成分多、含量高于同时蒸馏萃取法;将该挥发油用于卷烟加香,干姜挥发油加香浓度为0. 02%～0. 06%,烟草香味成分具有改善香气质和香气量、丰富烟香、减轻刺激,改善卷烟余味,且与烟香较协调的作用。     

挥发曲线法测定鹅不食草挥发油的研究

建立了鹅不食草挥发油含量测定新方法,并对水蒸汽蒸馏法一些提取条件(如粉末粗细,萃取溶剂,浸泡等)进行优化,以确定最佳提取方案。具体方法是:利用水蒸汽蒸馏法提取鹅不食草中挥发油,采用挥发曲线法测定挥发油含量。结果表明:水蒸汽蒸馏法的提取率最佳工艺是粉末先浸泡1～2 h,再进行水蒸气蒸馏法,用乙醚萃取为佳。挥发曲线法RSD为0.959%。挥发曲线法测定挥发油含量是一种成本低廉,操作简便,准确的测定方法。     

超临界CO2和微波辅助萃取辽细辛挥发油

通过超临界CO2萃取辽细辛挥发油均匀设计实验和微波诱导萃取的正交实验比较,考察了影响提取的主要因素,得到了最佳萃取工艺. 超临界CO2萃取最佳工艺条件为：压力16 MPa,温度32oC,CO2流量20 kg/h和时间80 min,得率为3.78%;微波萃取最佳工艺条件为：辐射功率720 W,辐射时间50 s,溶剂用量300 ml,洗涤溶剂用量30 ml,得率为5.46%. 水蒸馏法提取率为1.62%. 结果表明,超临界CO2和水蒸馏法萃取辽细辛挥发油品质最好;微波萃取收率最高,但品质较差.     

超临界CO2萃取丁香挥发油的实验研究

采用正交实验法对超临界CO2萃取丁香挥发油的条件进行了研究。考察了萃取温度、压力、CO2流量等因素在不同水平下对丁香挥发油提取率的影响。得到了超临界C02萃取丁香挥发油的最佳实验条件：萃取压力30MPa、温度40℃、CO2流量40kg／h和萃取时间80min,得率为20．62％。与水蒸气蒸馏法比较,超临界CO2萃取的收率高,萃取时间短。     

超临界CO2流体萃取辛夷挥发油化学组分的研究

本文在国内首次采用超临界ＣＯ_流萃取辛夷挥发油,利用色谱－质谱联用（ＧＣ－ＭＳ）法对挥发油进行了化学组分的定性和定量分析,鉴定出５５个组分,平均出油率为４．１５％,发现与文献水蒸汽蒸馏法所得之挥发油组分有相当差别。     

超临界CO_2流萃取及与水蒸气蒸馏萃取辛夷挥发油的化学组分分析

采用超临界ＣＯ２ 流萃取辛夷挥发油,对在不同条件下萃取的辛夷挥发油,用色谱－ 质谱（ＧＣ－ ＭＳ） 联用方法进行了化学组分的测定和分析,并与水蒸气蒸馏法所得之挥发油化学组分相比较,发现超临界ＣＯ２ 流萃取的挥发油香气、品质和产率均优于蒸馏法所得。     

石菖蒲挥发油的超临界CO2萃取工艺研究

考察了萃取压力、萃取温度、工作流量和时间等因素对超临界CO2萃取石菖蒲挥发油的影响.分别以萃取得到的挥发油得率、挥发油中α-细辛醚含量及α-细辛醚萃取率为指标,通过单因素试验获得石菖蒲挥发油超临界萃取的最佳工艺条件以及最佳萃取结果,即得油率4.86%,α-细辛醚含量3.17%,α-细辛醚萃取率1.26×10-3,同时也与水蒸气蒸馏方法进行了比较,结果表明超临界CO2萃取石菖蒲挥发油中α-细辛醚的含量要稍低于水蒸气蒸馏法,但其得油率及α-细辛醚的萃取率要明显优于传统的水蒸气蒸馏法.     

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.     

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.     

Novel polyurethane coating technology through glycidyl carbamate chemistry

Glycidyl carbamate chemistry combines the excellent properties of polyurethanes with the crosslinking chemistry of epoxy resins. Glycidyl carbamate functional oligomers were synthesized by the reaction of polyfunctional isocyanate oligomers and glycidol. The oligomers were formulated into coatings with several amine functional crosslinkers at varying stoichiometric ratios and cured at different temperatures. Properties such as solvent resistance, hardness, and impact resistance were dependent on the composition and cure conditions. Most coatings had an excellent combination of properties. Studies were carried out to determine the kinetics of the curing reaction of the glycidyl carbamate functional oligomers with multifunctional and model amines. Detailed kinetic analysis of the curing reactions was also undertaken. The results indicated that the glycidyl carbamate functional group is more reactive than a glycidyl ether group. Presented at the 82nd Annual Meeting of the Federation of Societies for Coatings Technology, on October 27–29, 2004, in Chicago, IL.