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101.
应用活化鲁米诺,用优化的增强化学发光酶联免疫分析体系测定人绒毛膜促性腺激素,检测限为0.2mIU/ml。线性范围0~200mIU/ml,与放射免分析测定结果比较,相关性良好。进而又发展了一种半定量的照相测定法,通过实际血清样品测定,效果良好。 相似文献
102.
PVA固定化脲酶电极的制作及电极特性的研究 总被引:2,自引:0,他引:2
利用PVA低温下的物理交联固定酶,制成酶电极并在不同尿素浓度、pH值、温度等条件下进一步研究这种酶电极的响应特性. 相似文献
103.
聚乙烯醇缩丁醛膜涂丝酶电极构造方法的研究 总被引:1,自引:0,他引:1
本文以三月桂胺为中性载体制成聚乙烯醇缩丁醛膜涂丝pH电极,再以该pH电极为换能器,采用三种共价交联固定化酶方法制成涂丝乙酰胆碱酯酶电极。该酶电极能用于测定0.1~10mmol/L浓度范围内的乙酰胆碱,响应时间在3~6min之内,寿命可达两个多月。 相似文献
104.
We report on a new enzyme/support system to immobilize proteins such as enzymes through a covalent bond on polysulfone membranes. In the present case the enzyme endo-1,4-β-xylanase (E.C.3.2.1.8) is attached to polysulfone previously derivatized by introducing an acrylate group. Membranes are properly prepared from this polysulfone acrylate. Afterwards the enzyme is immobilized though the amino groups of side chains of the amino acids of the enzyme and the acrylate group of the derivatized polysulfone. Such immobilization of the enzyme is confirmed by microelemental analysis as well as by amino acid analysis by HPLC. Moreover, the enzymatic activity of the membranes was evaluated and compared with that corresponding to the free enzyme. Certain physical parameters (asymmetry, irregularity, pore size and surface roughness) of the corresponding enzymatic membranes were obtained from SEM and AFM image interpretation. 相似文献
105.
以正庚烷的转化为探针反应 ,研究了添加元素锆对铂重整催化剂性能的影响规律。结果表明 ,在 4 50℃和连续流动条件下 ,Pt/γ -Al2 O3催化剂中引入锆不仅能够提高铂催化剂的稳定性和芳构化产率、抑制氢解和异构化 ,而且能使铂催化剂保持初活性。锆含量在 0 .56%左右 ,其调变作用最为显著。 相似文献
106.
Reaction of 2,3,7,8,12,13,17,18-octaethylporphyrin with LiR reagents containing functional groups readily yields meso substituted derivatives suitable for further transformations with residues such as -p-C6H5Br, -p-C6H5-CCH, -p-C6H5-NH2 or -(CH2)3-CHCH2. Similar reactions of tetrabenzoporphyrin with alkyllithium reagents afforded the first entry into meso mono- and dialkylsubstituted tetrabenzoporphyrins while reaction of bicyclo[2.2.2]oct-type masked isoindole precursors with LiR followed by in situ retro-Diels-Alder reaction also afforded the 5-phenyl and 5,10-diphenyltetrabenzoporphyrins in high purity. 相似文献
107.
The large number of possible chemical reactions represents a severe burdenfor modeling of even relatively simple plasma systems. Reduced sets ofchemical reactions have been obtained for numerical simulations of nitrogenand nitrogen-hydrogen plasma jets flowing into an atmospheric airenvironment. The important or active reactions are determined based on asimplified reduction method. A reaction is considered active if it leadsto higher sensitivities than a specified cutoff sensitivity of 1%. Theactive reactions exert a significant influence on main plasma parameters,such as velocity, temperature, and species concentrations. The sensitivityanalysis for the specified systems shows that two NO reactions, known asZel'dovich reactions (N2+ONO+N andNO+OO2+N),(1) are both active in a nitrogenplasma jet. On the other hand, the latter is not active and may be omittedin a nitrogen–hydrogen plasma jet. A nitrogen–hydrogen plasmajet requires contribution of two active charge exchange reactions:N2+N+N+
2+N andN+H+N+ +H, while only the former is needed in a nitrogen plasmajet. The dissociation reactions are all active in both plasma jets, exceptthe dissociation of OH. 相似文献
108.
There are many methods available for the detection of nucleotide variations in genetic material. Most of these methods are applied after amplification of the target genome sequence by the polymerase chain reaction (PCR). Many efforts are currently underway to develop techniques that can detect single nucleotide variations in genes either by means of, or without the need for, PCR. Allele-specific PCR (asPCR), which reports nucleotide variations based on either the presence or absence of a PCR-amplified DNA product, has the potential to combine target amplification and analysis in one single step. The principle of asPCR is based on the formation of matched or mismatched primer-target complexes by using allele-specific primer probes. PCR amplification by a DNA polymerase from matched 3'-primer termini proceeds, whereas a mismatch should obviate amplification. Given the recent advancements in real-time PCR, this technique should, in principle, allow single nucleotide variations to be detected online. However, this method is hampered by low selectivity, which necessitates tedious and costly manipulations. Recently, we reported that the selectivity of asPCR can be significantly increased through the employment of chemically modified primer probes. Here we report further significant advances in this area. We describe the synthesis of various primer probes that bear polar 4'-C-modified nucleotide residues at their 3' termini, and their evaluation in real-time asPCR. We found that primer probes bearing a 4'-C-methoxymethylene modification have superior properties in the discrimination of single nucleotide variations by PCR. 相似文献
109.
V. A. Bakulev Yu. O. Subbotina V. M. F. Fabian 《Chemistry of Heterocyclic Compounds》2003,39(11):1504-1515
The cyclization of 1,3,5-hexatrien-1-one, 1, and the Z- and E-isomers of 1-aza-1,3-butadienylketene 3 were studied using the semiempirical AM1 and PM3 methods. Cyclizations of compounds 1 and Z-3 are shown to occur via a mono-rotation mechanism with barriers of 15.49 and 32.85 kcal/mol respectively. The reactions proceed via non-planar transition states which result from rotation of the methylene group for compound 1 and the imino group for compound Z-3. Cyclization of E-3 proceeds via a non-rotatory mechanism through a planar transition state. The activation barrier is 4.83 kcal/mol (AM1). The electronic structures of the initial and final states, and of some intermediate structures, including the transition states for the cyclization of compounds 1 and 3, were analyzed by the natural orbital method using HF/6-31G*//AM1 calculations. Energetic, structural, and orbital criteria indicate the heteroelectric mechanism for the cyclization of compound E-3 and the pericyclic mechanism for the cyclization of compounds 1 and Z-3. 相似文献
110.
Kristin Odlo 《Tetrahedron letters》2007,48(12):2097-2099
1,4-Disubstituted 1,2,3-triazoles were obtained by a high-yielding copper(I) catalyzed 1,3-dipolar cycloaddition reaction between in situ generated azides and terminal acetylenes. This one-pot, two-step procedure tolerates most functional groups and circumvents the problems associated with the isolation of potentially toxic and explosive organic azides. 相似文献