毕赤酵母分泌表达植物病毒蛋白制备自组装纳米催化剂提高催化性能

病毒样颗粒（VLPs）包裹纳米粒子的亚细胞结构仿生设计在催化领域潜力巨大。本文构建了一株基于毕赤酵母（Pichia pastoris）的基因工程菌,用于分泌表达重组豇豆褪绿斑驳病毒衣壳蛋白（CCMV CPs）。通过表达工艺的优化（诱导温度30℃、诱导时间96h、每24h添加终浓度体积分数1.0%的甲醇）,可在发酵上清液中直接收获较高产量[(101.4±3.2)mg/L]和较高纯度（>90%）的衣壳蛋白。纯化后的CCMV CPs具有较强的体外自组装性能,能高效封装柠檬酸稳定的钌纳米颗粒（Ru-CA）（封装率约70%）,制备具有核壳结构的复合纳米催化剂Ru@VLPs。与非负载型催化剂Ru-CA相比,该催化剂在硝基芳烃包括4-硝基苯酚（4-NP）和3-硝基苯磺酸钠（3-NBS）还原反应中显示出较高的催化活性,表观反应速率常数（k）分别达到约0.14min^-1（4-NP还原反应）和0.16min^-1（3-NBS还原反应）。经计算,它催化的4-NP还原反应活化能为32kJ/mol,略低于Ru-CA（39kJ/mol）。Ru@VLPs较高的催化性能可归因于CCMV CPs封装Ru-CA后其分散性和稳定性的提高,以及Ru纳米颗粒与衣壳蛋白功能基团（如氨基,—NH₂）之间的协同作用。同时表明,Ru@VLPs亦具有较好的回收再利用性能。     

生物素-亲和素-DNA纳米颗粒信号放大检测载体的构建

目的构建用于检测细菌、病毒等病原体DNA的生物素-亲和素纳米颗粒信号放大载体。方法设计并合成两端和一端标记生物素的寡核苷酸探针(2B/1B-DNA),与抗生蛋白链菌素葡聚糖(Poly-STV)通过生物素与亲和素作用,偶联形成大分子纳米网状颗粒,并筛选最佳探针类型及其长度、2B-DNA和Poly-STV的浓度及比例和反应条件。结果2B-DNA和Poly-STV形成纳米颗粒信号放大载体的最佳浓度分别为1μmol/L和5μmol/L,最佳浓度比为1∶5,2B-DNA长度为60bp,缓冲液为Buffer B,反应条件为55℃,800r/min,20min。结论已成功构建了生物素-亲和素大分子纳米颗粒,可作为DNA检测信号放大技术的备选载体。     

纳米Al_2O_3负载Ru催化剂用于CO_2加氢合成甲酸研究

为了研究载体性质对Ru负载型催化剂的CO2加氢合成甲酸反应性能的影响,制备了以Al2O3纳米棒和γ-Al2O3为载体的一系列Ru基催化剂,采用透射电镜(TEM)、X射线衍射(XRD)、D2/OH交换和程序升温还原(H2-TPR)等方法详细表征催化剂的性质,并考察CO2加氢制甲酸的反应性能。结果表明:与传统Ru/Al2O3催化剂相比,以Al2O3纳米棒为载体时,Ru Ox物种在载体表面的分散程度高,Al2O3纳米棒的表面OH数目多,有利于提高催化剂的反应活性,另外当Ru在Al2O3纳米棒上的负载量(质量分数)为1%时,甲酸产量最高可以达到11.7mmol/h。     

Ru/C催化剂的制备及其催化双酚A加氢的研究

在碳酸丙烯酯(PC)中,用氢气还原氯化钌制备粒径均一的Ru纳米颗粒,并直接吸附到载体M(M=Si O2、Al2O3、Ti O2、活性炭)上,制得Ru/M催化剂。研究表明,以活性炭作为载体时,其催化效果最佳。采用X射线衍射(XRD)、X射线光电子能谱(XPS)、高分辨透射电镜(TEM)和比表面分析(BET)等手段对Ru/C催化剂的结构和表面特性进行表征。结果表明,Ru纳米颗粒在活性碳载体上均匀分散,粒径小于4 nm。以双酚A加氢反应对该催化剂进行考核,在120℃、4.0 MPa的反应条件下,双酚A的转化率为100%,氢化双酚A(HBPA)的选择性可达97.9%,表明该催化剂具有良好的双酚A催化加氢性能。     

温控相分离纳米Pd催化α, β-不饱和酮的选择加氢

以Pd(OAc)2、[CH3(OCH2CH2)22N+Et3][CH3SO3–](ILPEG1000)为原料,制得温控相分离Pd纳米催化剂,对其进行了UV-Vis和TEM表征.常压氢气条件下在α,β-不饱和酮的选择加氢反应中,Pd纳米催化剂显示了优异的催化性能.在最佳的反应条件下〔n(查尔酮):n(Pd)=500:1,n(ILPEG1000):n(Pd)=100:1,90℃,20 min,p=1.01×105 Pa(H2气球)〕,查尔酮的转化率和C==C双键加氢产物的选择性均>99％.Pd纳米催化剂易于与产物分离并可以循环使用6次,循环使用6次后转化率和选择性均>99％.转化频率(TOF)可达1470 h–1,高于目前文献中报道的常压氢气条件下过渡金属纳米催化剂催化查尔酮选择加氢反应的最高值(870 h–1).     

不同种类预过滤膜对纳米膜（DV20 nm）过滤人免疫球蛋白效果的影响

目的比较不同种类预过滤膜对纳米膜(DV20 nm)过滤人免疫球蛋白效果的影响。方法以A、B、C厂家生产的纳米膜(DV20 nm)和不同预过滤膜对1 000 mL 5. 3%IgG样品进行膜通量筛选实验,比较蛋白回收率及通量;应用筛选的预过滤膜和纳米膜对样品中滴度为6. 50 LgTCID50/0. 1 mL猪细小病毒(porcine parvovirus,PPV)进行去除病毒验证。结果选取A厂Minisart预过滤膜,120 min通量为7. 68 L/(m~2·h),蛋白回收率为96. 1%;B厂FTKDJL预过滤膜,120、300及400 min通量分别为9. 87、3. 93和1. 85 L/(m~2·h),蛋白回收率为97. 6%。A及B厂的纳米膜过滤约1 200 min,通量分别为2. 39和3. 74 L/(m~2·h),指示病毒PPV下降滴度分别为≥4. 63和≥4. 25 LgTCID50/0. 1 mL,均能在有效过滤量之内完全去除PPV,蛋白回收率均在96%以上。结论不同预过滤膜对纳米膜过滤通量有明显影响,筛选的预过滤膜及纳米膜均可有效去除PPV,可用于人免疫球蛋白规模化生产工艺。     

活性炭负载的纳米金催化剂上葡萄糖氧化工艺

采用溶胶固定法制备了一系列的Au/C纳米催化剂,进行了透射电镜(TEM)表征,用于常压下以氧气为氧化剂碱性溶液中葡萄糖氧化制备葡萄糖酸钠,并对最佳的催化剂进行了反应条件影响考察。结果显示,使用溶胶固定法制备的质量分数为1%的Au/C催化效果最佳,纳米金颗粒直径小于2 nm且分布均匀,其较佳反应条件为50℃,pH 9.5,氧气流量40 mL/min,催化剂0.22 g,水溶液中质量分数为7.5%的葡萄糖,葡萄糖在1 h内,选择性及转化率均可同时达到100%,反应的转化频率(Turnover Frequency,TOF)高达1 560 h-1。上述研究表明溶胶固定法能制备一定纳米金颗粒大小的Au/C催化剂,且在该多相催化剂上反应时间短,活性高,选择性高。     

基于铂碳催化加氢合成防老剂4030

以活性炭为载体,制备了铂负载型催化剂。透射电子显微镜、比表面积孔隙度分析仪、程序升温化学吸附仪等测试结果表明,铂金属颗粒均匀分布在活性炭表面,催化剂具有大的比表面积和金属活性面积,其对防老剂4030的合成具有很高的催化活性。防老剂4030的最佳合成工艺条件为:催化剂质量分数1.4%,5–甲基–2–己酮与PPD摩尔比3/1,反应压力4.5 MPa,反应温度110℃,搅拌速率650 r/min,反应时间2 h。此工艺条件下,对苯二胺(PPD)的转化率和防老剂4030的产率分别可达100%和99.2%。     

活性炭颗粒稳定化纳米级Pd/Fe复合颗粒对2-氯联苯的还原脱氯

利用超声波强化液相还原法制备活性炭颗粒(GAC)稳定化纳米级Pd/Fe复合颗粒,并对2-氯联苯(2-CB)进行催化还原脱氯研究。结果表明:40k Hz超声波辐照强化下制备的GAC稳定化纳米级Pd/Fe复合颗粒的比表面积、粒径和分散性均较普通液相还原法制备的复合颗粒有明显改善,粒径均在100nm以下,比表面积增大了21.73%。当复合颗粒钯化率为0.3%(质量分数)且GAC和Pd/Fe投加量分别为0.15g/L和5.0g/L时,在反应温度25℃、初始pH为3的条件下反应300min后,对初始质量浓度为10mg/L的2-CB降解率近95%,符合拟一级反应动力学,反应速率常数为3.88×10~(–2)min~(–1)。     

高分散度Ru/C选择性催化对氯硝基苯加氢制备对氯苯胺

研究了高分散度Ru/C在对氯硝基苯(p-CNB)加氢制备对氯苯胺(p-CAN)反应中的催化性能,考察了Ru负载量、溶剂种类、底物浓度、反应温度和压力等反应条件对反应的影响。结果表明,反应条件只影响p-CNB的加氢速率,但对p-CAN的选择性没有影响,p-CNB 100%转化时,p-CAN的选择性100%,没有脱氯副反应发生。催化剂的高活性和高选择性与纳米Ru在活性炭上的高分散度及催化剂的表面碱性有关。p-CNB浓度低于0.96mol/L时,还原反应对p-CNB宏观表现为零级反应。催化剂连续套用30次活性保持稳定。     

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.