The design and application of a fluorescent fiber-optic immunosensor (FFOI) are reported. The FFOI is utilized for the detection of antibody/antigen binding within the near-infrared (NIR) spectral region. The technique is developed through the combined use of fiber-optic, semiconductor laser-excitation, fluorescence detection, NIR dye, and immunochemical techniques. The antibody is immobilized on the FFOI and utilized as a recognition component for trace amounts of specific antigen. The FFOI is constructed to utilize an antibody sandwich technique. The assay involves the immobilization of the capture antibody on the sensing tip of the FFOI followed by the exposure of the immobilized sensing tip to the antigen. The antigen-coated FFOI is then introduced to a second antibody previously labeled with the NIR dye. Typical measurements are performed in about 15 min. A semiconductor laser provides the excitation (780 nm) of the immune complex. The resulting emission is detected by a silicon photodiode detector (820 nm). The intensity of the resulting fluorescence is directly proportional to the concentration of the antigen. The sensitivity of the analysis reaches 10 ng/ml and the response time is 10–15 min. 相似文献
Research on Chemical Intermediates - The aim of this study was to compare the degradation efficiency (DE%) of imidacloprid as a model pesticide by electro-Fenton (EF) and photoelectro-Fenton... 相似文献
Enzymatic cyclization of homocysteine forms a reactive thiolactone that may play an important role in its cardiovascular toxicity, but reliable quantitation of the free thiolactone metabolite in physiological fluids has not been reported. We have therefore used a highly selective gas chromatography/mass spectrometry (GC/MS) technique combined with the sensitivity of negative chemical ionization (NCI) to develop a quantitative method for the detection of homocysteine thiolactone (HcyTL) in plasma. To improve accuracy the deuterated isomer d(4)-HcyTL was synthesized and added to plasma as internal standard. The plasma was then treated with silica solid-phase extraction and derivatized with heptafluorobutyric anhydride. The derivative was analyzed by GC/MS in NCI mode with methane as the reagent gas and quantified by analyzing for the HcyTL ion [M(-)[bond]HF] and its d(4)-HcyTL counterpart in single-ion monitoring mode. The calibration curve showed a dynamic linear range up to 40 nmol/L. Within-day precision (n = 20, nominal concentration 5.2 nmol/L) was 0.96% and between-day precision was 3.9%, with a detection limit of 1.7 nmol/L and quantification limit of 5.2 nmol/L. Two human plasma samples had HcyTL concentrations of 18 and 25 nmol/L. This facile method for quantitation of homocysteine thiolactone opens the way for more detailed clinical studies of its potential role in homocysteine-induced arteriosclerosis and vaso-occlusive disease. 相似文献
We say that an R-module M is virtually semisimple if each submodule of M is isomorphic to a direct summand of M. A nonzero indecomposable virtually semisimple module is then called a virtually simple module. We carry out a study of virtually semisimple modules and modules which are direct sums of virtually simple modules . Our study provides several natural generalizations of the Wedderburn-Artin Theorem and an analogous to the classical Krull-Schmidt Theorem. Some applications of these theorems are indicated. For instance, it is shown that the following statements are equivalent for a ring R: (i) Every finitely generated left (right) R-module is virtually semisimple; (ii) Every finitely generated left (right) R-module is a direct sum of virtually simple R-modules; (iii) \(R\cong {\prod }_{i = 1}^{k} M_{n_{i}}(D_{i})\) where k,n1,…,nk ∈ ? and each Diis a principal ideal V-domain; and (iv) Every nonzero finitely generated left R-module can be written uniquely (up to isomorphism and order of the factors) in the form Rm1 ⊕… ⊕ Rmkwhere each Rmiis either a simple R-module or a virtually simple direct summand of R. 相似文献
A composite consisting of carbon nanotubes (CNT) and copper nanoparticles (CuNPs) was prepared by a chemical reduction method, and its structure characterized by scanning electron microscopy, transmission electron microscopy energy dispersive spectroscopy and FT-IR spectrometry. The hybrid composite was deposited on the surface of a disposable gold electrode that was manufactured from a commercial digital versatile gold disc by a drop casting method. The electrochemical properties of the modified electrode were investigated by cyclic voltammetry and differential pulse voltammetry. The sensor showed an excellent electrocatalytic activity towards oxidation of paracetamol (PA). The calibration plot (with current typically measured at 0.41 V vs. Ag/AgCl) is linear in the 0.5 to 80 μM concentration range, and the detection limit is as low as 10 nM. The sensor was successfully applied to the determination of PA in spiked water and tablet samples where it gave recoveries ranging between 95.25 and 100.5 %.
Graphical abstract Carbon nanotubes (CNT) -copper nanoparticles (CuNPs) hybrid composite was synthesized by a facile method then the nanohybrid was used as a modifier for the DVD gold electrode for improving its performance toward paracetamol electrooxidation. Cyclic voltammetry and differential pulse voltammetry were used for characterization and determination of paracetamol, respectively.
Novel metal organic frameworks including {(pipzH2)[Mn(py-2,3-dc)2]·7.75H2O}n, 1, {(pipzH2)[Zn(py-2,3-dc)2]·4H2O}n, 2, [Cd(py-2,3-dc)(H2O)3]n, 3 and {(pipzH2)[Hg4Cl10]}n, 4, in which pipz is piperazine and py-2,3-dcH2 is pyridine-2,3-dicarboxylic acid were synthesized applying a proton transfer ion pair i.e. (pipzH2)(py-2,3-dcH)2 and corresponding metallic salts and studied by IR, 1H NMR, 13C NMR spectroscopy and single crystal X-ray diffractometry. The space group of compounds 1 and 4 are P21/c and C2/c of monoclinic system, respectively. The crystal dimensions are a = 20.108(2) Å, b = 19.910(2) Å, c = 12.997(1) Å, β = 94.354(2)° for 1 and a = 15.940(1) Å, b = 11.2690(9) Å, c = 11.1307(9) Å, β = 90.685(2)° for 4. The crystal structures of 2 and 3 have been reported previously. However, their solution studies are discussed here. The compounds had all polymeric structures. Although ZnII, CdII and HgII were elements of the same group, their behavior against the ion pair was essentially different. Various supramolecular interactions mainly hydrogen bonds of the type O-H?O, N-H?O, C-H?O, N-H…Cl and C-H?Cl were observed in the structures. There was an unusual and huge water cluster in the structure of compound 1. The solution states of compounds 1–4 were studied and reported. The protonation constants of pipz and py-2,3-dc, the py-2,3-dc/pipz proton transfer equilibrium constants and stoichiometry and stability of the system with Mn2+, Zn2+, Cd2+ and Hg2+ ions in aqueous solution were investigated by potentiometric pH titrations. 相似文献
A widely used result of Wedderburn and Artin states that “every left ideal of a ring R is a direct summand of R if and only if R has a unique decomposition as a finite direct product of matrix rings over division rings.” Motivated by this, we call a module Mvirtually semisimple if every submodule of M is isomorphic to a direct summand of M and M is called completely virtually semisimple if every submodule of M is virtually semisimple. We show that the left R-module R is completely virtually semisimple if and only if R has a unique decomposition as a finite direct product of matrix rings over principal left ideal domains. This shows that R is completely virtually semisimple on both sides if and only if every finitely generated (left and right) R-module is a direct sum of a singular module and a projective virtually semisimple module. The Wedderburn-Artin theorem follows as a corollary from our result. 相似文献
Research on Chemical Intermediates - A simple and convenient procedure for the synthesis of 5-arylidene barbituric acid, pyrano[2,3-d]pyrimidinone and 4-hydroxycoumarin derivatives using... 相似文献
Research on Chemical Intermediates - A 2,2′-Bipyridine-based ionic compound named 2,2′-bipyridinium dihydrogen phosphate was synthesized by addition of phosphoric acid to a solution of... 相似文献