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Easy Preparation (easy + preparation)
Selected AbstractsAn Easy Preparation of Pyridinium N-Heteroarylaminides.CHEMINFORM, Issue 23 2004M. Jose Reyes Abstract For Abstract see ChemInform Abstract in Full Text. [source] DNA Hybridization at Magnetic Nanoparticles with Electrochemical Stripping DetectionELECTROANALYSIS, Issue 23 2004Ningning Zhu Abstract A simple and practical method for electrochemical DNA hybridization assay has been developed to take advantage of magnetic nanoparticles for ssDNA immobilization and zinc sulfide nanoparticle as oligonucleotide label. Magnetic nanoparticles were prepared by coprecipitation of Fe2+ and Fe3+ with NH4OH, and then amino silane was coated onto the surface of magnetite nanoparticles. The magnetic nanoparticles have the advantages of easy preparation, easy surface modification and low cost. The target ssDNA with the phosphate group at the 5, end was then covalently immobilized to the amino group of magnetite nanoparticles by forming a phosphoramidate bond in the presence of 1-ethyl-3-(3-dimeth-ylaminopropyl)carbodiimide (EDAC). The zinc sulfide (ZnS) nanoparticle-labeled oligonucleotides probe was used to identify the target ssDNA immobilized on the magnetic nanoparticles based on a specific hybridization reaction. The hybridization events were assessed by the dissolution of the zinc sulfide nanoparticles anchored on the hybrids and the indirect determination of the dissolved zinc ions by anodic stripping voltammetry (ASV) at a mercury film glassy carbon electrode (GCE). The proposed method couples the high sensitivity of anodic stripping analysis for zinc ions with effective magnetic separation for eliminating nonspecific adsorption effects and offers great promise for DNA hybridization analysis. [source] Multi-walled carbon nanotube composites with polyacrylate prepared for open-tubular capillary electrochromatographyELECTROPHORESIS, Issue 19 2010Jian-Lian Chen Abstract A new phase containing immobilized carbon nanotubes (CNTs) was synthesized by in situ polymerization of acid-treated multi-walled CNTs using butylmethacrylate (BMA) as the monomer and ethylene dimethacrylate as the crosslinker on a silanized capillary, forming a porous-layered open-tubular column for CEC. Incorporation of CNT nanomaterials into a polymer matrix could increase the phase ratio and take advantage of the easy preparation of an OT-CEC column. The completed BMA-CNT column was characterized by SEM, ATR-IR, and EOF measurements, varying the pH and the added volume organic modifier. In the multi-walled CNTs structure, carboxylate groups were the major ionizable ligands on the phase surface exerting the EOF having electroosmotic mobility, 4.0×104,cm2,V,1,S,1, in the phosphate buffer at pH 2.8 and RSD values (n=5), 3.2, 4.1, and 4.3%, for three replicate capillaries at pH 7.6. Application of the BMA-CNT column in CEC separations of various samples, including nucleobases, nucleosides, flavonoids, and phenolic acids, proved satisfactory upon optimization of the running buffers. Their optima were found in the borate buffers at pH 9.0/50,mM, pH 9.5/10,mM/50% v/v ACN, and pH 9.5/30,mM/10% v/v methanol, respectively. The separations could also be used to assess the relative contributions of electrophoresis and chromatography to the CEC mechanism by calculating the corresponding velocity and retention factors. Discussions about interactions between the probe solutes and the bonded phase included the ,,, interactions, electrostatic repulsion, and hydrogen bonding. Furthermore, a reversed-phase mode was discovered to be involved in the chromatographic retention. [source] Design of Biomolecular Interfaces Using Liquid Crystals Containing Oligomeric Ethylene GlycolADVANCED FUNCTIONAL MATERIALS, Issue 13 2010Zhongqiang Yang Abstract An investigation of nematic liquid crystals (LCs) formed from miscible mixtures of 4-cyano-4,-pentylbiphenyl (5CB) and 2-(2-[2-{2-(2,3-difluoro-4-{4-(4- trans -pentylcyclohexyl)-phenyl-phenoxy)ethoxy}ethoxy]ethoxy)ethanol (EG4-LC) is reported, the latter being a mesogen with a tetra(ethylene glycol) tail. Quantitative characterization of the ordering of this LC mixture at biologically relevant aqueous interfaces reveals that addition of EG4-LC (1%,5% by weight) to 5CB causes a continuous transition in the ordering of the LC from a planar (pure 5CB) to a perpendicular (homeotropic) orientation. The homeotropic ordering is also seen in aqueous dispersions of micrometer-sized droplets of the LC mixture, which exhibit enhanced stability against coalescence. These observations and others, all of which suggest partitioning of the EG4-LC from the bulk of the LC to its aqueous interface, are complemented by measurements of the adsorption of bovine serum albumin to the aqueous,LC interface. Overall, the results demonstrate a general and facile approach to the design of LCs with interfaces that present biologically relevant chemical functional groups, assume well-defined orientations at aqueous interfaces, and lower non-specific protein adsorption. The bulk of the LC serves as a reservoir of EG4-LC, thus permitting easy preparation of these interfaces and the potential for spontaneous repair of the EG4-decorated interfaces during contact with biological systems. [source] Meshless thermo-elastoplastic analysis by triple-reciprocity boundary element methodINTERNATIONAL JOURNAL FOR NUMERICAL METHODS IN ENGINEERING, Issue 13 2010Yoshihiro OchiaiArticle first published online: 18 SEP 200 Abstract In general, internal cells are required to solve thermo-elastoplasticity problems by a conventional boundary element method (BEM). However, in this case, the merit of BEM, which is the easy preparation of data, is lost. A conventional multiple-reciprocity boundary element method (MRBEM) cannot be used to solve elastoplasticity problems, because the distribution of initial strain or stress cannot be determined analytically. In this study, it is shown that without the use of internal cells, two-dimensional thermo-elastoplasticity problems can be solved by a triple-reciprocity BEM using a thin plate spline. Initial strain and stress formulations are adopted and the initial strain or stress distribution is interpolated using boundary integral equations. A new computer program was developed and applied to solve several problems. Copyright © 2009 John Wiley & Sons, Ltd. [source] A New Strategy for the Synthesis of Polyaniline Nanostructures: From Nanofibers to NanowiresMACROMOLECULAR RAPID COMMUNICATIONS, Issue 6 2007Jing Li Abstract A new approach for the synthesis of polyaniline (PANI) nanostructures under UV light illumination has been developed, which is the first report of a templateless chemical process for preparing pure PANI nanowires. The acceleration effect of photo-assistance on the polymerization can promote the homogeneous nucleation and elongation of the nanofibers and nanowires, leading to easy preparation of tunable diameters of the nanowires and nanofibers of PANI. [source] High-performance affinity chromatography with immobilization of protein A and L-histidine on molded monolithBIOTECHNOLOGY & BIOENGINEERING, Issue 5 2002Quanzhou Luo Abstract Reactive monoliths of macroporous poly(glycidyl methacrylate- co -ethylene dimethacrylate) have been prepared by "in-situ" copolymerization of the monomers in the presence of porogenic diluents. Protein A and L-histidine were immobilized on the monoliths directly or through a spacer arm, respectively. The properties of these two kinds of affinity columns were characterized, and the results showed that the columns with coupling of ligands by a spacer arm have some extent of non-specific adsorption for bovine serum albumin. The affinity column based on the monolithic polymer support provided us with good hydrodynamic characteristic, low flow resistance, and easy preparation. These two affinity columns were used for the purification of immunoglobulin G from human serum. The purity of the purified IgG was detected by matrix-assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF-MS). The stability of the protein A affinity column was investigated, and its performance remained invariable after half a year. The effects of the nature and the pH of the buffer system on the adsorption capacity of human IgG on histidyl affinity column were also investigated. The protein A affinity column is favorable for rapid analysis of human IgG samples. In contrast, the advantages of mild elution conditions, high stability, as well as low cost provide the histidyl column further potential possibility for fast removal of IgG from human plasma in clinical applications. © 2002 Wiley Periodicals, Inc. Biotechnol Bioeng 80: 481,489, 2002. [source] Cycloaddition of CO2 to Epoxides Catalyzed by Polyaniline SaltsCHEMISTRY - A EUROPEAN JOURNAL, Issue 24 2007Jinling He Abstract The catalytic activity of polyaniline-HX (X=I, Br, Cl) (PANI-HI, PANI-HBr, PANI-HCl) for the cycloaddition of CO2 to propylene oxide (PO) to produce propylene carbonate (PC) was studied for the first time. It was shown that all the PANI salts were active for the reaction, and PANI-HI was most active and selective. On the basis of the preliminary results, the effect of the reaction conditions on the cycloadditions of CO2 to propylene oxide and epichlorohydrin was further investigated by using PANI-HI as the catalyst. The results indicated that the optimized temperature was around 115,°C. The maxima occurred in yield versus pressure curves at about 5,MPa for both substrates. Complete conversion was achieved in 3,h for epichlorohydrin and 6,h for propylene oxide at 115,°C and 5,MPa. With propylene oxide as the substrate, the reusability of PANI-HI was evaluated and no loss of catalytic activity was detectable after the catalyst had been reused five times. The catalyst was characterized by thermogravimetric analysis (TGA) and scanning electron microscopy (SEM), which provided further evidence for the high stability of the catalyst. We believe that the catalyst has great potential for industrial applications because it has some unusual advantages, such as its easy preparation, high activity, selectivity, stability, low cost, and simple separation from products. [source] | ||||||||||||||||