107 resultados para 497


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The molecular spectroscopy (including near infrared diffuse reflection spectroscopy, Raman spectroscopy and infrared spectroscopy) with OPUS/Ident software was applied to clustering ginsengs according to species and processing methods. The results demonstrate that molecular spectroscopic analysis could provide a rapid, nondestructive and reliable method for identification of Chinese traditional medicine. It's found that the result of Raman spectroscopic analysis was the best one among these three methods. Comparing with traditional methods, which are laborious and time consuming, the molecular spectroscopic analysis is more effective.

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Natural bone is one kind of compounds consisting of hydroxyapatite (HAp) nano-rods, which are embedded in the template of collagen matrix in vivo with the same crystallographic organization. Herein HAp nano-rods precursors were synthesized via wet chemical method. Large-scale HAp nano-wires with the same crystallographic organization as the template of anodic aluminum oxide (AAO) were obtained by the electrophoretic deposition and the technology of the template. It provides a meaningful method to study and understand the information of biological molecules' mineralization process.

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Lanthanocene chlorides (C4H7OCH2C9H6)(2)LnCl[Ln=Y(1); Ln=Gd(2)] were synthesized by the reaction of tetrahydrofurfurylindenyl lithium(in situ) with corresponding anhydrous lanthanide chorides in THF. The crystal structures of these two complexes were determined by X-ray diffraction and they were unsolvated monomeric complexes. They were stable in the air for several hours. Complexes 1 and 2 belong to the same crystal system (orthorhombic) and space group(P2(1)2(1)2(1)). The unit cell dimensions of complex 1 were a=1.042 52(9) nm, b=1.47455(12) nm, c=1.497 99(13) nm, Z=4, D-c=1.508 g/cm(3); The unit cell dimensions of complex 2 were a=1.037 01(10) nm, b=1.472 33(12) nm, c=1.513 54(14) nm, Z=4, D-c=1.699 g/cm(3). They have the same structure and different space configurations. The central metal atom is coordinated by two indenyl, two oxygen of the tetrahydrofurfuryl and one chlorine atom to form a distorted trigonal bipyramid.

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The electroanalysis research of deoxyribonucleic acid (DNA) is an attractive project in life science. This paper reviews the recent progress of DNA electrochemical analysis, which includes DNA electroanalysis and DNA electrochemical biosensors. The prospects of the research are very bright. 77 papers are cited.

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就DNA电分析化学研究及其应用方面进行综述 ,主要叙述了DNA的各种电分析化学方法 ,以及DNA电化学传感器的原理、应用以及发展。

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A series of high sulfonated poly(ether ether ketone)s were prepared by copolymerization of sodium 5,5 ' -carbonylbis (2-fluorobenzenesulfonate)(2),4,4 ' -difluorobenzophenone (1) and bisphenol A(3) in the presence of potassium carbonate in dimethylsulfoxide. The copolymers were characterized by IR and DSC, The influence of degree of sulfonation on the properties of copolymers, such as component, thermal stability, solubility and filming ability, was studied.

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用 3 ,3’-二磺酸钠基 -4 ,4 -二氟二苯酮合成了具有高磺化度的荷电聚醚醚酮 .用红外吸收光谱及 DSC对其进行了表征 .研究了共聚物的组成、热稳定性、溶解性、成膜性及磺化度对共聚物性能的影响

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A new heteropolycomplex, K6H3[ZnW11O40Al] . 9.5H(2)O was prepared and characterized by means of elemental analysis, IR, UV spectroscopy, Al-27 NMR, electrochemistry and X-ray crystallography. The crystal of K6H3[ZnW11O40Al] . 9.5H(2)O is cubic, space group Fm-3m, with lattice constants a=b=c=2. 144 8(2) nm, V = 9.866(2) nm(3), Mo radiation, R = 0.057 8 for 497 independent data with [I>2 delta(I)]. The anion is of alpha-type Keggin structure with C-s symmetry.

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A novel type of electrochemical detector based on a polyaniline-dispersed mercury-coated glassy carbon chemically modified electrode was investigated for the detection of monochloramine and dichloramine. A polyaniline dispersed-mercury modified electrode, which was prepared by coating polyaniline on a thin mercury film electrode using fast-sweep voltammetry, was developed. The selectivity could be altered using various counter ions incorporated into the polymer. The results indicated that the use of a conducting polymer-based electrochemical sensor for the selective determination of chloramine is a feasible approach.

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The heterogeneous electron transfer reaction of hemeproteins including hemoglobin, myoglobin and cytochrome C at Pt mesh electrode adsorbed methylene blue has been investigated. Thin-layer spectroelectrochemical technique was used for observing the electron transfer processes of three kinds of proteins, and the corresponding electrode rate constants were measured.

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本文研究了几种血红素蛋白质包括牛血红蛋白,人肌红蛋白和马心细胞色素C在亚甲蓝修饰电极上的非均相电子转移反应,采用光透薄层光谱电化学法监测了血红素蛋白质的直接电化学反应过程,并进行了动力学研究.

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A transformation model for Laminaria japonica was established from 1993 to 1998, on the basis of which the transgenic kelp with heterologous gene encoding hepatitis B surface antigen (HBsAg) was obtained by using the micro-particle bombardment transformation method. Results of quantitative ELISA showed that HBsAg in transgenic kelp was 0.529 mug/mg soluble proteins on average and the highest value was 2.497 mug/mg, implying that recombinant HBsAg had natural epitope. Further support for the integration of HBsAg gene into kelp genome was obtained by PCR-Southern and total DNA hybridization. Prospect of kelp bio-reactor producing high value materials such as edible HBV vaccine was discussed as well.

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This paper reports for the first time the transient expression of a reporter gene, LacZ, in the unicellular green alga Haematococcus pluvialis. By employing the micro-particle bombardment method, motile cells in the exponential phase showed transient expression of lacZ. This was detected in bombarded motile cells under the rupture-disc pressures of 3103 KPa and 4137 KPa. Transient expression of LacZ gene could not be observed in non-motile cells of this alga under the same transformation condition. No LacZ background was found in either the motile cells or the non-motile cells. The study suggests a promising potential of the SV40 promoter and the lacZ reporter gene in genetic engineering of unicellular green algae.

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The unicellular green alga Haematococcus pluvialis accumulates a commercially valuable astaxanthin, with levels reaching up to 4% dry weight under environmental stress. In recent years, much effort has been devoted to understanding the molecular mechanisms regulating astaxanthin biosynthetic pathways. Beta-carotene ketolase (bkt), with control being exhibited at the transcription level, plays an important role in astaxanthin biosynthesis by H. pluvialis. Here we demonstrate the presence of two separate 5'-flanking regions [1.5 kilobase (kb) and 2 kb] of bkt (bkt1 and bkt2) that possess regulatory elements similar to those of known stress-responsive genes in plants. Results of 5'-deletion constructs and transient beta-galactosidase expression assays demonstrate that there may be positive regulatory elements governing expression in the shorter promoter at -1060/-900 from the 1.5 kb 5' region, and in the longer promoter at -1838/-1219 and at -1046/ -734 from the 2 kb 5' region relative to each homologous ATG start codon. Furthermore, our present studies reveal that the first intron (+371/+497) downstream from the 1.5 kb 5' untranslated region of bkt1 may function as a negative regulatory element to regulate its own promoter.