负载薄荷香精微孔淀粉的制备及其表征

采用双酶水解法制备糯玉米微孔淀粉,并吸附薄荷香精制备香精微孔淀粉有机微球。研究了酶解反应时间、淀粉乳质量分数以及酶质量分数对微孔淀粉产率和吸附率的影响,并采用SEM、粒径分析、热重分析对微孔淀粉进行表征。通过单因素实验和正交试验得到优化工艺条件为:反应时间5 h,淀粉乳质量分数28.6%,酶质量分数3%,此条件下微孔淀粉的平均产率为25.7%,平均吸附率为111.7%。SEM观察微孔淀粉形态完好;其粒径大小为10μm左右;热重分析测得吸附于微孔淀粉上香精的开始分解温度较未吸附前有所提高。     

微孔淀粉的工艺研究

微孔淀粉是一种新型的变性淀粉。介绍了酸法和高温α-淀粉酶与糖化酶联用的方法水解玉米淀粉制备微孔淀粉,通过比较发现酶法优于酸法。并且当高温α-淀粉酶与糖化酶联用重量比为1∶3、pH=4.5、50℃、水解18 h时,可获得吸油率较高的微孔淀粉。     

微孔木薯淀粉的制备及结构表征研究

利用微波处理,α-淀粉酶和葡萄糖苷酶协同水解制备微孔木薯淀粉,通过扫描电镜研究微孔木薯淀粉的形貌。采用氮气吸附法测定微孔木薯淀粉的吸附/脱附等温线,计算其比表面积、比孔容积以及孔径分布。微孔木薯淀粉的孔径分布主要集中在2~40 nm之间,是富含中孔的吸附剂。     

α-淀粉酶水解番薯淀粉的研究

用α-淀粉酶水解番薯淀粉制备微孔淀粉,研究在不同的酶用量、温度、pH值、番薯淀粉浓度和反应时间条件下,考察番薯微孔淀粉吸附性能的变化规律,进而获得最佳的工艺条件。实验得出:当α-淀粉酶用量为1.0%、温度为40℃、pH值为4.60、番薯淀粉用量为25 g、反应时间为4 h时,得到番薯微孔淀粉的吸附性能最佳。     

盐酸水解制备红薯微孔淀粉的研究

研究在不同的盐酸浓度、温度、淀粉用量和反应时间条件下,通过单因素实验和正交实验取得最佳工艺条件。利用盐酸水解红薯淀粉制备微孔淀粉,通过吸油率考察了微孔淀粉吸附性能。盐酸浓度为1.5%、温度为45℃、淀粉用量为20g、反应时间为8h时,制备红薯微孔淀粉的吸附性能最佳。     

双酶一步法水解马铃薯淀粉的动力学研究

本文以山西五寨马铃薯淀粉为原料,应用α-淀粉酶和糖化酶进行了双酶协同水解淀粉的动力学研究,建立了修正的双酶一步法水解马铃薯淀粉的动力学速度方程。协同作用阶段dS/dt=VmlS0/Km1 S0;dG/dt=Vm20S/Km20(1 G/Ki) S 协同作用结束后-dS/dt=Vm2S1/1.1/Km2(1 G/Ki) Si dG/dt=Vm2S/Km2(1 G/Ki) S实验结果与计算机模拟结果吻合良好。     

采用酶的糖化法制造葡萄糖

葡萄糖的制造,在工业上向来是将淀粉加酸水解而制成。亦可从木材加酸而制得,但工艺过程比较复杂。近时糖化酶的研究日益进展,利用糖化酶由淀粉制造葡萄糖,经过试用结果,认为此法较加酸水解有一些优点,一部分业已正式投入生产。每日产葡萄糖在10吨以上。糖化酶是由培养微生物而获得,用于葡萄糖制造所用的糖化酶,必需具备下述条件: (1)由淀粉生成葡萄糖的糖化率约100%。(2)当作用于高浓度(约40%)的淀粉溶液时,糖甙移转酶的活性小,因为此酶具有异麦芽糖、潘糖和其它寡糖类的逆合成作用,而使葡萄糖受到损失。可以生产符合上述两项的糖化酶的微生物不多,     

微孔玉米淀粉的制备工艺研究

以玉米淀粉为原料,采用酸水解的处理方法,研究制取微孔淀粉的最佳工艺条件和技术参数,同时结合扫描电子显微镜观察,研究淀粉经处理形成微孔后颗粒的表观特征和理化性质,并初步探讨微孔淀粉作为吸附剂吸水和吸油性能。研究结果如下：酸处理制备玉米微孔淀粉的最佳反应条件：5％盐酸、反应时间18h、反应温度52℃、淀粉乳浓度36％。实验表明制备的微孔淀粉具有良好的吸水和吸油性能。     

生物酶法制备白果微孔淀粉及其特性研究

以白果淀粉为原料,用生物酶降解的方法制备微孔淀粉,研究制备条件对白果淀粉成孔的影响。通过单因素和正交试验确定酶法制备白果微孔淀粉的最优工艺条件为：20g白果淀粉,酶种类为α-淀粉酶,酶用量2．0％,pH值5．5,酶解温度40℃,酶解时间18h,白果微孔淀粉的得率为92．5％,吸水率由102％提高到162％。采用扫描电子显微镜（SEM）和差示扫描量热仪（DSC）对白果微孔淀粉的颗粒结构和热特性进行分析,并将其与原白果淀粉进行比较。结果表明,制备的白果微孔淀粉表面有凹坑或孔洞,内部有空腔,其糊化温度范围（温差7．69℃）较原淀粉变窄（温差8．27℃）。焓变值为1．913J/g,较原淀粉无明显变化。     

多孔淀粉的生物法制备、改性及应用

多孔淀粉是一种中空变性淀粉,有超声波照射、喷雾、机械撞击、醇变性和酸水解等多种生产方法.介绍了酶水解制备多孔淀粉的影响因素和条件,并探讨了多孔淀粉的吸附性质和流变学性质,以及现代分析技术(扫描电子显微镜、差示扫描量热法、X射线衍射法、布拉班德黏度仪、比表面积分析仪等)在多孔淀粉研究中的基本应用状况.     

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。     

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.     

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.