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971.
Sun Z Jin L Shi W Wei M Evans DG Duan X 《Langmuir : the ACS journal of surfaces and colloids》2011,27(11):7113-7120
This article reports a novel method to tune the photoluminance properties of ammonium 1-anilinonaphthalene-8-sulfonate (ANS) in a 2D matrix of layered double hydroxide (LDH) by changing the interlayer microenvironment. ANS and a series of surfactants with different alkyl chain lengths (pentanesulphonate (PES), hexanesulphonate (HES), heptanesulphonate (HPS), decanesulphonate (DES), and dodecylsulphonate (DDS)) were respectively cointercalated into the galleries of ZnAl-LDH by the anion exchange method. Thin films of ANS/surfactant-LDHs obtained by the solvent evaporation method possess good c orientation as revealed by XRD and SEM. It was found that the ANS/HPS-LDH film showed the maximum fluorescence efficiency and the longest intensity-average lifetime among these ANS/surfactant-LDH composites owing to the "size-matching" rule between the organic dye and surfactant. Moreover, the fluorescence properties can be tuned by changing the relative molar ratio of ANS/HPS, and the film containing 20% ANS (molar percentage, expressed as ANS(20%)/HPS-LDH) exhibits the maximum fluorescence efficiency, the longest average lifetime, and significantly enhanced photo and thermal stability. In addition, the composite films show fluorescence anisotropy, attributed to the preferential orientation of ANS in the LDH gallery. Therefore, this work demonstrates a feasible approach to tuning the photoluminescence properties of a dye confined in an inorganic 2D matrix via changing the interlayer microenvironment, which may be considered to be a good candidate for solid photoluminescence materials, nonlinear optics, and polarized luminescence materials. 相似文献
972.
Hua Liu Xuan Wu Ying Huang Jing He Sai-Feng Xue Zhu Tao Qian-Jiang Zhu Gang Wei 《Journal of inclusion phenomena and macrocyclic chemistry》2011,71(3-4):583-587
Interaction between cucurbit[8]uril (Q[8]) with a fungicide, carboxin in aqueous solution, was investigated by 1H-NMR, electronic absorption spectroscopy, and fluorescence spectroscopy. Spectroscopy analysis established a basic interaction model which formed an inclusion complex with a host:guest ratio of 1:1. 1H-NMR showed that Q[8] encapsulated the phenyl ring into its cavity and the rest of the guest molecule stayed outside the host. Comparative in vitro evaluations of the growth inhibitory effects of the inclusion complex solution toward Rhizoctonia solani demonstrated appreciable improvements in the antifungal activity of carboxin through the addition of Q[8]. In comparison with the positive control, improvement was evaluated in terms of area covered by the mycelia of R. solani and their growth inhibition rate. Inclusion complexation of carboxin with Q[8] suggests a potential means for production of an environmentally friendly carboxin-based fungicide to counteract R. solani. 相似文献
973.
The hydroxide of meso-tetraphenylporphyrin derivatives functionalized carbon nanotubes (CNTs) was fabricated in our research to explore the interaction between porphyrin and explosive. It was turned out that in the formation of grid porphyrin film, carbon nanotubes as a cruciul base materials promoted the electron transfer rate. Most of important, the results also showed that the electrochemical response was enhanced through increasing the number of -OH substitution in porphyrin. Such information provides the platform for a practical strategy for rational design of the sensor of explosives. 相似文献
974.
Deming Huang Shanhong Wan Liping Wang Qunji Xue 《Surface and interface analysis : SIA》2011,43(7):1064-1068
Tungsten trioxide‐incorporated hydrogenated amorphous carbon (WO3/a‐C:H) films have been fabricated on a single‐crystal silicon wafer by liquid phase electrodeposition using methanol as carbon source and tungsten carbonyl as incorporated reagent. The morphology, composition and structure of the films have been investigated by SEM, XPS, Raman scattering spectroscopy, Fourier transform infrared spectroscopy (FTIR) and Transmission electron microscope (TEM), respectively. The effects of WO3 incorporation on the electrical and wetting properties were studied in detail. The characterization results showed that tungsten trioxide nanocrystalline particles with diameters in the range of 10–20 nm were homogenously embedded in the amorphous carbon films. Also, the electrical conductivity and wetting ability of the films were strongly improved due to the contribution of the tungsten trioxide. Copyright © 2010 John Wiley & Sons, Ltd. 相似文献
975.
One-dimensional GdVO4:Ln3+ (Ln=Eu, Dy, Sm) nanofibers have been prepared by a combination method of sol-gel process and electrospinning technology. X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), thermogravimetric and differential thermal analysis (TG-DTA), scanning electron microscopy (SEM), transmission electron microscopy (TEM), photoluminescence (PL), quantum efficiency (QE), and cathodoluminescence (CL) spectra as well as kinetic decays were used to characterize the samples. The XRD, FT-IR, and TG-DTA results show that GdVO4:Ln3+ nanofibers samples crystallize at 700 °C. SEM images indicate that the as prepared precursor fibers are smooth. After being calcined at 700 °C for 4 h, the fibers still maintain their fiberlike morphology with rough surface. TEM image further manifests that the GdVO4:Ln3+ nanofibers consist of nanoparticles. Under ultraviolet excitation and low-voltage electron beam excitation, GdVO4:Ln3+ phosphors showed their strong characteristic emission due to an efficient energy transfer from vanadate groups to dopants. The optimum doping concentration of Ln3+ in the GdVO4 nanofibers also has been investigated. 相似文献
976.
Pan Xue Yongming Li Zhujun Zhang Aihua Fu Fei Liu Xiaoming Zhang Yuanjie Sun Lili Chen Boquan Jin Kun Yang 《Mikrochimica acta》2011,174(1-2):167-174
An enzyme-linked immunosorbent assay, a horseradish peroxidase-catalyzed fluorogenic reaction, and chemiluminescence (CL) analysis have been combined to develop a sandwich ELISA for Staphylococcal enterotoxin B (SEB) using monoclonal antibodies for different epitopes of SEB. The enzyme catalyzed reaction of 3-(4-hydroxyphenyl propionate) with the urea complex of hydrogen peroxide produced a fluorescent dimer which was detected by chemiluminescence analysis. The CL response to SEB is linear in the range from 6.0 to 564?pg?mL?1 (r?=?0.9993), and the detection limit is 3.3?pg?mL?1 (S/N?=?3). Intra- and interassay coefficients of variation are <7.0% at three concentrations (24, 96 and 384?pg?mL?1). The method was applied to the analysis of SEB in serum, lake water and milk samples. The results compared well with those obtained by conventional ELISAs. Figure
Procedures of the proposed method. A sandwich ELISA for Staphylococcal enterotoxin B (SEB) using a pair of monoclonal antibodies that recognizes different epitopes of SEB. After the ELISA procedure, PHPPA is reacted with Hydrogen peroxide-urea, with catalysis by HRP-conjugated anti-SEB, to produce PHPPA fluorescent Dimer, which is detected by TCPO chemiluminescence. 相似文献
977.
978.
以廉价的异香草醛和2,4,6-三羟基苯乙酮为起始原料,经过C-异戊烯基化、选择性甲基化、甲氧甲基化、羟醛缩合、去保护基、催化环化以及脱除甲基等步骤,分别以13.3%和23%的总收率首次完成了天然异戊烯基黄烷酮Glovanon(1)和5-O-methylglovanon(2)的全合成.合成的关键步骤是2,4,6-三羟基苯乙酮的单C-异戊烯基化.所有新化合物的结构都经过1H NMR,IR,MS确认.抑菌活性研究表明,两种新合成的化合物对藤黄微球菌(M.luteus)和大肠杆菌(E.coli)均有良好的抑制作用. 相似文献
979.
980.
Fu H Pang S Xue P Yang J Liu X Wang Y Li T Li H Li X 《Applied biochemistry and biotechnology》2011,165(2):465-475
Fibroblast growth factor-21 (FGF21) is a hepatic hormone that plays a critical role in metabolism, stimulating fatty acid
oxidation in the liver and glucose uptake in adipose tissue. In this study, we produced tobacco plants expressing human recombinant
FGF21 (hFGF21) via Agrobacterium-mediated transformation using a potato virus X (PVX)-based vector (pgR107). The vector contained the sequence encoding the
human FGF21 gene fused with green florescence protein and a histidine tag. The recombinant plasmid was introduced into leaf
cells of Nicotiana benthamiana (a wild Australian tobacco) via Agrobacterium-mediated agroinfiltration. As determined by fluorescence and Western blot of leaf extracts, the hFGF21 gene was correctly
translated in tobacco plants. Seven days after agroinfection, the recombinant hFGF21 had accumulated to levels as high as
450 μg g−1 fresh weight in leaves of agroinfected plants. The recombinant hFGF21 was purified from plant tissues by Ni–NTA affinity
chromatography, and the purified hFGF21 stimulated glucose uptake in 3T3/L1 cells. This indicated that the recombinant hFGF21
expressed via the PVX viral vector in N. benthamiana was biologically active. 相似文献