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251.
A new dual‐amplification strategy of electrochemical signaling from antigen–antibody interactions was proposed via backfilling gold nanoparticles on (3‐mercaptopropyl) trimethoxysilane sol‐gel (MPTS) functionalized interface. The MPTS was employed not only as a building block for the electrode surface modification but also as a matrix for ligand functionalization with first amplification. The second signal amplification strategy introduced in this study was based on the backfilling immobilization of nanogold particles to the immunosensor surface. Several coupling techniques, such as with nanogold but not MPTS or with MPTS but not nanogold, were investigated for the determination of carcinoembryonic antigen (CEA) as a model, and a very good result was obtained with nanogold and MPTS coupling immunosensor. With the noncompetitive format, the formation of the antigen–antibody complex by a simple one‐step immunoreaction between the immobilized anti‐CEA and CEA in sample solution introduced membrane potential change before and after the antigen–antibody interaction. Under optimal conditions, the proposed immunosensor exhibited a good electrochemical behavior to CEA in a dynamic concentration range of 4.4 to 85.7 ng/mL with a detection limit of 1.2 ng/mL (at 3 δ). Moreover, the precision, reproducibility and stability of the as‐prepared immunosensor were acceptable. Importantly, the proposed methodology would be valuable for diagnosis and monitoring of carcinoma and its metastasis. 相似文献
252.
The definition of bond index introduced by Ehrenson, and written in terms of bond order and overlap integrals, has been applied to a series of nitriles. A good correlation between heats of formation and a linear equation in the indices for each bond present is obtained. This was extended to include the results for a set of hydrocarbons. 相似文献
253.
The adsorption of α1-acid glycoprotein into bilirubin/cholesterol mixed monolayers with various component molar ratios is investigated using surface
pressure-area (π-A) isotherms and (dπ/dA)-A curves. The results showed that the surface area per molecule increased after the adsorption/insertion of glycoprotein molecules
into the monolayers. The compressibility of mixed monolayers increased as a result of hydrogen bonding between bilirubin and
glycoprotein molecules, while the interactions between bilirubin and cholesterol are weakened. The adsorption of glycoprotein
into a monolayer induced changes in molecular surface area depending on the surface pressure and molar fraction of bilirubin.
The transmission electron microscopy of mixed monolayers confirmed the insertion of glycoprotein particles of spherical shape
with an average diameter of about 80 nm into the monolayer.
The text was submitted by the authors in English. 相似文献
254.
The chemisorption of NO on clean Pt(111), Rh/Pt(111) alloy, and Pd/Pt(111) alloy surfaces has been studied by first principles density functional theory (DFT) computations. It was found that the surface compositions of the surface alloys have very different effects on the adsorption of NO on Rh/Pt(111) versus that on Pd/Pt(111). This is due to the different bond strength between the two metals in each alloy system. A complex d-band center weighting model developed by authors in a previous study for SO2 adsorption is demonstrated to be necessary for quantifying NO adsorption on Pd/Pt(111). A strong linear relationship between the weighted positions of the d states of the surfaces and the molecular NO adsorption energies shows the closer the weighted d-band center is shifted to the Fermi energy level, the stronger the adsorption of NO will be. The consequences of this study for the optimized design of three-way automotive catalysts, (TWC) are also discussed. 相似文献
255.
Fingerprint quality control of Tianjihuang by high-performance liquid chromatography-photodiode array detection 总被引:5,自引:0,他引:5
A novel, simple and accurate fingerprint method was developed using high-performance liquid chromatography-photodiode array detection (HPLC-DAD) for the quality control of Hypericum japonicum thunb (Tianjihuang), a Chinese herbal medicine used for the treatment of several bacterial diseases, infectious hepatitis, gastrointestinal disorder, internal hemorrhage and tumors. For the first time, the feasibility and advantages of employing chromatographic fingerprint were investigated and demonstrated for the evaluation of Tianjihuang by systematically comparing chromatograms with a professional analytical software recommended by State Food and Drug Administration (SFDA). Our results revealed that the chromatographic fingerprint combining similarity evaluation could efficiently identify and distinguish raw herbs of Tianjihuang from different sources. The effects resulted from collecting locations, harvesting time and storage time on herbal chromatographic fingerprints were also examined. 相似文献
256.
Liu BD Bando Y Tang CC Xu FF Golberg D 《The journal of physical chemistry. B》2005,109(46):21521-21524
GaN nanowires with P doping were synthesized via a simple thermal evaporation process. The P-doped GaN nanowires have average diameters of approximately 100 nm and lengths up to tens of micrometers. Scanning electron microscope and high-resolution field-emission transmission electron microscope analyses revealed that P doping results in a rough surface morphology of GaN nanowires. Field-emission measurements showed that P doping effectively decreases the turn-on field of GaN nanowire to 5.1 V/mum, holding promise of application as an electron emitter. The rough surface is responsible for enhancement of the field-emission properties of GaN nanowires. 相似文献
257.
258.
Hui-Ning D Wen-Chen Z Shao-Yi W Sheng T 《Spectrochimica acta. Part A, Molecular and biomolecular spectroscopy》2004,60(3):489-492
In this paper, we calculate the EPR parameters (g factors g parallel, g perpendicular and hyperfine structure constants A parallel, A perpendicular) of rare earth ion Sm3+ in fluoride crystals KY3F10 and LiYF4 from the perturbation formulas of EPR parameters for a 4f5 ion in tetragonal symmetry. In these formulas, the crystal-field J-mixing of the first and second excited-state multiplets 6H(7/2) and 6H(9/2) into the ground state multiplet 6H(5/2), the mixtures among the states with the same J value via spin-orbit coupling interaction and the interactions between the ground Kramers doublet Gammagamma and the same irreducible representation as Gammagamma in other 11 Kramers doublets Gammax within 6HJ (J=5/2, 7/2, 9/2) states via crystal-field and orbital angular momentum (or hyperfine structure) are considered. The calculated results (which are in agreement with the observed values) are discussed. 相似文献
259.
IntroductionItiswellknownthatyttriumcanbeusedinmanyfields ,suchasmetallurgy ,ceramics ,lasersandelectron ics ,especiallyinfluorescentmaterialswhoseneedforhighpurityyttriumoxideisincreasing .InChina ,there sourceofyttriumisrich ,andthehighpureyttriumisbe ingo… 相似文献
260.
可再生甲壳素吸附铬(Ⅵ)的特性研究 总被引:9,自引:0,他引:9
可再生甲壳素吸附铬(Ⅵ)的特性研究陈炳稔*汤又文李国明万春华(华南师范大学化学系广州510631)关键词可再生甲壳素,制备,铬(Ⅵ),吸附1997-08-19收稿,1997-12-23修回广东省科委及高教厅资助课题利用甲壳素作为铬(Ⅵ)的捕集剂已有报... 相似文献