水溶性壳聚糖纳米粒子的制备及其BSA载药性能

为了避免高分子量壳聚糖水溶性差以及增溶剂乙酸可能带来的负面作用,本文选择低分子量水溶性壳聚糖 (WSC)作研究对象,采用三聚磷酸(TPP)作交链剂制备不同WSC/TPP比率的WSC纳米粒子,并用于牛血清白蛋白 (BSA)的释放载体。经测得为球形形貌的纳米粒子空载和载药时粒径、Zeta电位分别在35～190 nm、35～42 mV。红外光谱及X–射线衍射证实了纳米粒子中WSC的氨基与TPP的磷酸基团发生了交联反应。纳米粒子载药性能试验表明在0.05～1 mg/mL范围内随着BSA浓度的增大,纳米粒子的载药量增加而负载率降低。体外释放实验表明水溶性壳聚糖纳米载体对蛋白质药物具有缓释特征。因此,水溶性壳聚糖有望成为新的载体应用于蛋白质药物的控制释放。     

止血性壳聚糖的制备及其凝血效果的研究

在温和均相条件下,对较高脱乙酰度的壳聚糖进行乙酰化,制备不同脱乙酰度的壳聚糖;测试不同脱乙酰度和分子量的壳聚糖醋酸溶液的凝血效果。中药—壳聚糖复合止血材料的制备及其止血功能的研究。     

聚氨基葡糖的成膜及其应用基础理论研究(Ⅰ)——成膜因素及其对膜性能的影响

研究了不同脱乙酰度的聚氨基萄糖(以下简称壳聚糖)交联剂、交联时间及不同操作压力等因素对壳聚糖微孔膜分离效率的影响。研究表明,以乙二醛为交联剂,交联反应一天,膜液浓度越高,膜的性能越好;脱乙酰度越大的壳聚糖,交联后的膜分离效率越高。     

微波间歇法快速制备高粘均分子量和高脱乙酰度的壳聚糖

使用微波间歇法可快速制备高脱乙酰度和高粘均分子量的壳聚糖. 单因素实验确定的工艺条件为微波功率800 W,将45%(w)的氢氧化钠溶液与250~380 mm的20 g甲壳素粉以8:1的体积比混合,在100℃下反应10 min,洗涤、微波干燥后在相同条件下再反应1次,共20 min,可制得脱乙酰度为94.5%、粘均分子量1.48×106的白色壳聚糖粉末. 其他制备条件相同,使用电加热法间歇处理甲壳素粉3次,反应共5 h,可以得到脱乙酰度为96.2%、粘均分子量为3.8×105的褐色壳聚糖粉末. 微波间歇法所制壳聚糖的结晶度高,内部有规整的有序结构,用它制备的膜致密,性能优于用电加热法所制壳聚糖制备的膜.     

新型天然交联剂氧化海藻酸钠制备及其性能研究

用高碘酸钠氧化海藻酸钠(ALG),制备具有二醛结构的部分氧化海藻酸钠(ADA),对醛基化过程中ALG结构、氧化度、醛基含量和粘均分子量进行研究.以剩余NaIO4与KI反应的碘显色法,考察ALG氧化程度,得出氧化动力学曲线;用粘度法得到ADA分子量.结果表明,ALG的氧化度随高碘酸钠量的增加而增加,12 h后在70%左右趋于平缓;氧化反应因为自由基存在,ALG由原来的分子量为28万变为氧化后的1万左右,并不随高碘酸钠用量的变化而变化.制得的ADA与壳聚糖溶液反应.交联生成凝胶,并且凝胶时间与ADA浓度增加而缩短,证明其具有交联作用,为应用于支架材料复合打下基础.     

聚氨基葡糖的成膜及其应用基础理论研究（I）

研究了不同脱乙酰度的聚氨基葡糖交联剂、交联时间及不同操作压力等因素对壳聚糖微孔膜分离效率的影响。研究表明，以乙二醛为交联剂，交联反应一天，膜液浓度超高，膜的性能越好；脱乙酰度越大的壳聚糖，交联后的分离效率越高。     

壳聚糖理化性能:粘均分子量、脱乙酰度及结晶性能测定

使用粘度法测定了阿拉丁牌低粘、中粘、高粘和沪试牌四种壳聚糖的分子量,分别约为126万,115万,69万和56万。分别使用酸碱滴定法和双突跃电位滴定法测定了脱乙酰度,结果表明后者更精密,四类壳聚糖的脱乙酰度值均在78%～86%之间。X射线衍射测得阿拉丁牌壳聚糖具有相对较低的结晶度,脱乙酰度降低导致结晶度下降。     

壳聚糖的表面性能及分子量与脱乙酰度的影响

应用红外光谱法对四种壳聚糖样品进行了结构表征,同时估算了其脱乙酰度,并用粘度法测定了分子量。根据Washburn的浸渍理论和van Oss-Chaudhury-Good的组合理论,应用柱状灯芯技术,对壳聚糖的表面性能进行了测试。研究发现,壳聚糖的分子量和脱乙酰度都影响其表面性能。当脱乙酰度相同时,分子量与表面能γS及表面能分量γSLW、酸碱比值γS+/γS-成正比,而与其酸性力γS+和碱性力γS-以及极性率γAB/γs成反比;而分子量相近时,表面性能可能主要受脱乙酰度的影响。随着脱乙酰度的增加,壳聚糖的表面能γS及其分量γSLW、酸碱比值γS+/γS-都增大。实验所测得的壳聚糖的表面能数据得到文献的支持。     

壳聚糖在醋酸溶液中的溶解行为及动力学模型

用电导和粒度测试两种方法研究了壳聚糖在醋酸溶液中的溶解行为。结果显示:醋酸浓度、溶解温度和壳聚糖样品本身的脱乙酰度及分子量都会影响壳聚糖的溶解,但溶解初期壳聚糖因吸附醋酸根离子而产生聚集现象。一般情况下,温度高有利于壳聚糖的溶解。当壳聚糖脱乙酰度非常高,分子量差距又并不是非常大时,前者将对溶解起主导作用,同时脱乙酰度越高越有利于其溶解。     

从柠檬酸厂废黑曲霉菌丝体中提取壳聚糖的工艺研究

确定了从柠檬酸厂废黑曲霉菌中制备壳聚糖的工艺条件,得到了白色壳聚糖产品,其中脱乙酰度80.48%,1%壳聚糖的1%醋酸溶液的运动粘度为5.41×10-4m2.s-1,粘均分子量为7.89×104,灰分为10%,得率为7.2%。     

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。