富G寡核苷酸-N-甲基卟啉二丙酸荧光法测定铀

富G寡核苷酸形成的G四聚体能与NMM作用导致荧光显著增强,在酸性环境下,UO2+2与NMM优先作用使荧光猝灭并抑制NMM与G四聚体的作用。以λex=399 nm为激发波长,测量加入UO2+2前后λem=609 nm处的荧光变化值,线性范围为1.29×10-7⁷.0×10-6mol/L,线性回归方程为:ΔF=4.91+3.91 c(×10-7mol/L),r=0.999 4,检测限为3.86×10-8mol/L,相对标准偏差为2.3%7.0×10-6mol/L,线性回归方程为:ΔF=4.91+3.91 c(×10-7mol/L),r=0.999 4,检测限为3.86×10-8mol/L,相对标准偏差为2.3%³.9%。实验首次发现UO2+2能猝灭NMM荧光,已应用于铀模拟样品的测定,具有选择性好、精密度和准确度高等优点。     

罗丹明Schiff碱型比色探针的合成及对Cu~(2+)的识别

以7-羟基-4-甲基-8-香豆素醛和罗丹明B酰肼为原料,经缩合反应得到可选择性识别Cu2+的比色探针L,并利用1HNMR、MS和元素分析对其结构进行了表征。通过紫外-可见光谱法研究了探针L在缓冲液(V(CH3CN)∶V(Tris-HCl)=1∶1,pH=6.0)中对金属离子的识别能力。随着Cu2+加入,探针L在λ=557 nm处产生强的可见吸收响应,溶液由无色迅速转变为紫红色。在0.6×10-6~1.6×10-6mol/L范围内,Cu2+的浓度与吸光度呈线性关系,最低检测限为6.6×10-8mol/L。探针L与Cu2+形成1∶1型配合物,识别过程可逆。     

富G寡核苷酸-N-甲基卟啉二丙酸荧光法测定铀

富G寡核苷酸形成的G四聚体能与NMM作用导致荧光显著增强,在酸性环境下,UO2+2与NMM优先作用使荧光猝灭并抑制NMM与G四聚体的作用。以λex=399 nm为激发波长,测量加入UO2+2前后λem=609 nm处的荧光变化值,线性范围为1.29×10-7~7.0×10-6mol/L,线性回归方程为:ΔF=4.91+3.91 c(×10-7mol/L),r=0.999 4,检测限为3.86×10-8mol/L,相对标准偏差为2.3%~3.9%。实验首次发现UO2+2能猝灭NMM荧光,已应用于铀模拟样品的测定,具有选择性好、精密度和准确度高等优点。     

色酮-3-甲醛席夫碱新型荧光探针高选择性检测CN离子

以色酮-3-甲醛和3-氨基吡唑为原料,通过一锅法缩合反应得到新型猝灭型席夫碱荧光探针Z.在V(DMSO):V(H2 O)=3:2的溶液中,通过选择性、灵敏度、抗干扰、稳定性及pH影响等实验,证实该探针具有较好的稳定性,能够高灵敏度和选择性地识别CN-,最低检测限为1.9×10-8 mol/L.进一步荧光滴定实验和机理研...     

基于Schiff碱结构的Cu~(2+)荧光探针的合成及性能研究

合成了一种以氟化硼络合二吡咯甲川类染料为荧光团,Schiff碱结构为识别体的Cu2+荧光猝灭探针。在pH7.36的缓冲溶液中,当Cu2+浓度达到5.0×10-5mol/L时,探针在最大发射波长为518 nm处的荧光强度减弱80%以上,且其识别作用不受其他金属离子干扰。Cu2+浓度在3.0×10-7~7.0×10-6mol/L范围内,探针的荧光强度与Cu2+浓度有较好的线性关系,可以定量检测中性水溶液中Cu2+含量。     

Eu3+掺杂TiO2荧光探针的制备及对氯氰菊酯的检测应用

以钛酸四丁酯为前体,采用液相法制备了水溶态纳米Eu3+掺杂TiO2荧光探针,并对其发光性质进行了研究。通过紫外吸收和荧光光谱研究了它和氯氰菊酯之间的相互作用,结果发现,氯氰菊酯对Eu3+掺杂TiO2的荧光具有猝灭作用,根据Stern-Volmer猝灭方程,计算出其猝灭常数为1.017×1011 L/(mol.s),并讨论了猝灭机理。依据氯氰菊酯浓度和Eu3+掺杂TiO2的荧光强度成正比,建立了一种快速检测农药的新方法。其检测范围为2.5×10-10～2.5×10-7mol/L,检出限为2.5×10-11mol/L,回收率在89.25%～93.55%之间。     

新荧光试剂双[3-(3,5-二溴吡啶)重氮氨基]-联苯的合成及其分析应用

合成了新荧光试剂双[3-(3,5-二溴吡啶)重氮氨基]-联苯(BBPDDP)。其结构经元素分析、红外光谱证实。研究表明,在碱性介质中,该试剂在λex/λem=248 nm/304 nm处产生荧光,且能与Fe3+配合并使BBPDDP的荧光猝灭。据此建立了BBPDDP对Fe3+的新荧光分析法。该方法的线性范围为4.5×10-9~9.0×10-7 mol/L,检测限为8.4×10-9 mol/L。将其应用于香蕉中Fe3+的测定,结果满意。     

淀粉基铽(Ⅲ)配合物的制备及荧光检测性能

制备了一个基于氧化淀粉纳米颗粒(OSNP)的稀土铽(Ⅲ)配合物OSNP@Tb~(3+),在320 nm激发波长下,该物质能发射强烈的绿色荧光。将OSNP@Tb~(3+)作为生物荧光探针检测不同抗生素时,发现该物质对呋喃唑酮的检测有较高的灵敏性和选择性。OSNP@Tb~(3+)水分散液的荧光强度随呋喃唑酮浓度的增加逐渐减少,当呋喃唑酮浓度为2.3×10~(–4) mol/L时,荧光基本完全猝灭(猝灭效率90%)。OSNP@Tb~(3+)水分散液对呋喃唑酮的检测具有较高的猝灭常数(K_(sv)=1.919×10~4 L/mol)、良好的线性关系(R~2=0.992)和低的检测限(1.67×10~(–6) mol/L)。     

葡萄糖修饰的水溶性荧光锌离子化学传感器

设计合成了一个氨基葡萄糖修饰的水溶性锌离子荧光增强型化学传感器,并借助核磁共振谱和质谱对其结构进行了表征,利用荧光光谱法研究了该传感器对不同金属离子的荧光响应。结果显示,在4-羟乙基哌嗪乙磺酸(HEPES)缓冲溶液中,该传感器能与Zn2+配位且在发射波长490 nm处荧光显著增强,除Cu2+、Ni2+、Co2+和Cr3+对此配合物荧光强度有不同程度猝灭外,其他金属离子的加入均没有引起其明显变化,说明传感器对Zn2+有较好的选择性;同时,Job曲线表明二者形成了结合比为2∶1的稳定配合物。     

多巴胺的纸基检测——负载ZnO量子点的细菌纤维素复合膜

以γ-氨丙基三乙氧基硅烷(ATPES)为表面修饰剂,通过溶胶-凝胶法制备水溶性的ZnO量子点。以细菌纤维素(BC)为基体,采用物理吸附法制备了负载ZnO量子点的BC复合膜。采用紫外-可见光谱仪、X射线衍射仪、傅里叶变换红外光谱仪、荧光光谱仪、透射电子显微镜对材料的结构和性能进行了表征,并用于多巴胺的荧光检测,得出荧光猝灭方程中的猝灭常数K_(sv)=3.18×10~5L/mol,检测限为6.5×10~(-8)mol/L,并分析了荧光猝灭的反应机制。     

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.     

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.     

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.     

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.