电化学法制备氧化亚铜的研究

采用电化学法制备氧化亚铜粉末,研究了电解液组成及其浓度、温度以及电流密度等因素对氧化亚铜产品质量的影响,得到了电化学法制备氧化亚铜的优化工艺条件:c(NaCl)=260～290 g·l-1,c(NaOH)=0.1～1.0 g·l-1(pH=11.1～12.1),电解温度:80～85℃,电流密度500～1000 A·m-2.对影响产品质量的原因进行了分析和探讨.     

赖氨酸脱羧酶发酵工艺及酶学性质

考察了蜂房哈夫尼菌(H.alveiAS1.1009)的L-赖氨酸脱羧酶对L-赖氨酸的脱羧作用,分析了培养基、温度、pH、激活剂等因素对酶活力的影响。实验结果表明,最适培养基成分为:ρ(蔗糖)=20 g/L、ρ(玉米浆)=20g/L、ρ(酵母膏)=5 g/L、ρ(牛肉膏)=3 g/L、ρ(蛋白胨)=10 g/L、ρ(氯化钠)=5 g/L、ρ(硫酸铵)=2 g/L、ρ(维生素B6)=5 g/L和ρ(L-赖氨酸)=5 g/L,100 mL发酵液中接种量为5 mL液体菌种。最佳转化工艺条件为:转化体系温度35℃、pH=5.0,ρ(菌体)=10 g/L,ρ(吐温-80)=0.15 g/L。L-赖氨酸脱羧酶在最适发酵和转化条件下比酶活可达7 984.43 U,底物转化率可达70%。     

假单胞菌AB93066产鼠李糖脂发酵条件的优化

通过单因素实验和正交实验对铜绿假单胞杆菌AB93066产鼠李糖脂(RL)的摇瓶发酵培养基配方和产生规律进行了研究。结果表明,最佳培养基配方为:ρ(酵母膏)=0.2 g/L,ρ(豆油)=120 g/L,ρ(NaNO3)=6.5 g/L,ρ(KH2PO4)=1.0 g/L,ρ(Na2HPO4.12H2O)=1.0 g/L,ρ(MgSO4.7H2O)=0.1 g/L,ρ(FeSO4.7H2O)=0.2 g/L,pH=6.0。RL的收获期在发酵后156~168 h最佳。发酵生产RL的扩大实验表明,在最优发酵条件下RL的产量可达56 g/L以上,提取后的RL可将去离子水的表面张力降至29.01 mN/m。用高效液相色谱/质谱联用仪进一步分析了所提取的RL的组成,它分别为二鼠李糖脂(R1)和单鼠李糖脂(R2)两种同系物。R1和R2的表观临界胶束浓度(CMC)分别为0.03 mmol/L和0.04 mmol/L。     

化学镀制备激光ICF磁性PS靶材的研究

为了制备可以在磁场中悬浮的ICF靶丸材料,采用化学镀法对PS微球包覆Ni-P合金磁性镀层,并用正交实验确定了最佳工艺条件。采用XRD、SEM、DSC、VSM分析了镀层结构、形貌以及磁性。结果表明,Ni-P镀层在PS微球表面沉积均匀,表面光滑;微球的饱和磁化强度为2.130 A/m,所具有的磁性可使其在磁场中悬浮;化学镀Ni-P合金层最佳工艺条件为:ρ(NiSO4.6H2O)=40 g/L,ρ(NaH2PO2)=25 g/L,ρ(柠檬酸钠)=50 g/L,pH=10,温度为40℃。     

Fenton氧化法处理含乌洛托品废水

通过实验优化了Fenton试剂法氧化处理含乌洛托品废水的反应条件。实验表明,当ρ(H2O2)=8.25g/L,n(H2O2)∶n(Fe)=20∶1,pH=3.0,在35℃下反应5h以后,CODCr可从1250mg/L降到<100mg/L。但当温度降低到15℃时,出水CODCr则很难降到<100mg/L。在同样的反应条件下,连续流完全混合反应器的出水CODCr明显高于间歇反应的出水。     

复合载体固定化大肠杆菌制备γ-氨基丁酸

用卡拉胶与明胶复合载体固定大肠杆菌,优化了固定化细胞的制备条件,并利用该复合载体固定大肠杆菌细胞进行酶法制备γ-氨基丁酸的研究。实验结果表明,最佳工艺条件为:m(卡拉胶):m(明胶)=3:2,ρ(混合胶)=12g/L,ρ(KCl)=60g/L,固定化时间为3h,ρ(菌体)=80g/L,反应温度为37℃,转化体系pH=4.8,ρ(底物)=40g/L。固定化细胞在最适条件下比酶活高达10740U。包埋1.0g湿菌体的固定化细胞重复使用7次,可把42gL-谷氨酸完全转化为γ-氨基丁酸。     

苯丙氨酸脱氨酶发酵工艺及其酶学性质研究

选育出一株具有较高苯丙氨酸脱氨酶活性的菌株巨大芽孢杆菌AS1.127-NJU10。考察了该菌的发酵产酶条件,结果表明:蔗糖为最佳碳源、酵母浸膏和NH4C l组成最佳氮源,其质量浓度分别为:ρ(蔗糖)=20 g/L,ρ(酵母浸膏)=2 g/L和ρ(NH4C l)=10 g/L;发酵培养基最适pH=6.5,培养温度为37℃;诱导物ρ(L-苯丙氨酸)=1 g/L时,酶活最高达1 070 U。同时对苯丙氨酸脱氨酶的性质进行了研究,结果表明:该酶最适pH=5.8,最适温度为40℃,反应液中添加φ(吐温-80)=0.2%和c(K+)=10-5mol/L能明显提高酶活。     

复合电沉积制备镍-石墨烯电极及其电催化析氢性能研究

以紫铜为基体,电沉积制备了镍还原氧化石墨烯(Ni-RGO)复合电极,研究了石墨烯质量浓度、电流密度、pH、温度和时间对Ni RGO复合电极的电催化析氢性能。得到最佳配方和工艺条件为:Ni(NH2SO3)2·4H2O 350 g/L,NiCl2·6H2O 10 g/L,C6H8O7·H2O 5 g/L,H3BO320 g/L,十二烷基苯磺酸钠0.12 g/L,RGO 0.16 g/L,pH 3.5,温度40°C,电流密度5 A/dm^2,时间10 min。该条件下所得Ni-RGO复合电极的电催化析氢性能最佳。     

从牛眼玻璃体中分离纯化透明质酸的新方法

为了得到一种简便的从动物组织中分离纯化透明质酸(HA)的新方法,用牛眼玻璃体为原料,对HA的分离纯化进行了研究。在ρ(NaHCO3)=7.56 g/L和ρ(Na2CO3)=1.06 g/L的碱性缓冲水溶液中,用胰蛋白酶水解牛眼HA提取物中的蛋白质,经氯苯除杂后,用乙醇析出并分离得到HA初级沉淀物,将其溶解于ρ(NaC l)=11.6 g/L,ρ(NaH2PO4.12H2O)=0.45 g/L,ρ(Na2HPO4.2H2O)=0.06 g/L的含盐磷酸盐水溶液中,再用3倍体积的乙醇析出并分离得到HA的首次纯化沉淀物,此纯化阶段分离系数(α)=19.03,蛋白质和HA中w(HA)=63.9%,HA回收率91.84%。其次,用含盐磷酸盐水溶液溶解HA的首次纯化沉淀物,再加入ρ(活性炭)=50 g/L及ρ(高岭土)=100 g/L进行吸附纯化,此纯化阶段分离系数(α)=27.69,HA回收率94.0%,w(DNA)=0%,蛋白质和HA中w(HA)=98.0%。最后,经50 000 Da透析袋用去离子水透析4 h,用乙醇析出并分离得到纯化了的HA沉淀,此纯化阶段分离系数(α)=17.64,HA回收率93.5%。最终HA沉淀经冷冻干燥后获白色粉末状HA纯化品,无水HA纯化品中w(HA)=99.77%,HA相对分子质量Mη=6.3×105。该方法牛眼玻璃体质量扩大至2 000 mL的扩试结果与小试结果相近。该文报道工作的新颖性,已为2007年4月18日由陕西省科学技术信息研究所查新中心出具的第2007360-3号《科技查新报告》所证实。     

Ni-P-纳米TiO_2化学复合镀镀液稳定性研究

在确定纳米TiO2超声分散工艺的基础上,采用正交试验和单因素比较法,系统研究了镀液配比、pH值、温度、PbCl2和纳米TiO2加入量对Ni-P-纳米TiO2化学复合镀镀液稳定性的影响。研究结果表明:镀液的配比、pH值、温度对镀液稳定性均有影响,其影响的显著性顺序是:pH值小于乳酸浓度小于温度小于镍磷比小于乙酸钠浓度的影响;PbCl2的加入可使镀液的稳定性明显提高,而纳米TiO2的加入对镀液的稳定性几乎没有影响;推荐Ni-P-纳米TiO2化学复合镀采用的镀液为:x(Ni2+/H2PO2-)=0 4,ρ(乳酸)=34g/L、ρ(乙酸钠)=4g/L、ρ(PbCl2)=0 0010g/L、ρ(TiO2)=4g/L。     

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.     

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.     

ICP-MS法测定地球化学样品中As、Cr、Ge、V等18种微量痕量元素的研究

建立了测定地球化学样品中包括As、Cr、Ge、V等18种微量、痕量元素的ICP-MS方法。地化试样用HF-HNO3混酸分解后,以1 1 HNO3溶解干渣。由于制样不使用盐酸,避免了Cl对As、Cr、Ge、V的质谱干扰。用国家一级地球化学标准物质GBW 07309制备溶液优化仪器工作参数,并用于校准。方法测定限(6s)为:0.007~6.4μg/g,精密度(RSD%,n=12)为:29%~9.4%,经过国家一级地球化学标准物质的分析验证,结果与标准值吻合。方法已应用于国土资源调查的试样分析。