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Selected AbstractsHighly Efficient Access to Bi- and Tricyclic Ketals through Gold-Catalyzed Tandem Reactions of 4-Acyl-1,6-diynesCHEMISTRY - A EUROPEAN JOURNAL, Issue 8 2009Jia Meng Dr. Abstract Single step: Fused bicyclic and bridged tricyclic ketals were synthesized in a single step from the reactions of easily available 4-acyl-1,6-diynes with H2O and alkanols (see scheme). The highly efficient AuCl3 -catalyzed multicomponent domino reactions, involving five CO bond formations, can proceed in a highly regio- and diastereoselective manner at room temperature under air and lead to structures of high molecular complexity from simple starting materials in an atom economic way. [source] Monoclonal antibody proteomics: Discovery and prevalidation of chronic obstructive pulmonary disease biomarkers in a single stepELECTROPHORESIS, Issue 23 2007Eszter Csanky Abstract We define mAb proteomics as the global generation of disease specific antibodies that permit mass screening of biomarkers. An integrated, high-throughput, disease-specific mAb-based biomarker discovery platform has been developed. The approach readily provided new biomarker leads with the focus on large-scale discovery and production of mAb-based, disease-specific clinical assay candidates. The outcome of the biomarker discovery process was a highly specific and sensitive assay, applicable for testing of clinical validation paradigms, like response to treatment or correlation with other clinical parameters. In contrast to MS-based or systems biology-based strategies, our process produced prevalidated clinical assays as the outcome of the discovery process. By re-engineering the biomarker discovery paradigm, the encouraging results presented in this paper clearly demonstrate the efficiency of the mAb proteomics approach, and set the grounds for the next steps of studies, namely, the hunt for candidate biomarkers that respond to drug treatment. [source] Proteomic analysis of rat brain tissue: Comparison of protocols for two-dimensional gel electrophoresis analysis based on different solubilizing agentsELECTROPHORESIS, Issue 24 2002Lucia Carboni Abstract The present study reports a comparison of recently described solubilizing methods, to set up a simple protocol for obtaining two-dimensional (2-D) gel electrophoresis maps of brain tissue. Different protocols were used for preparing rat brain homogenates and the resulting maps were compared by image analysis. Three different detergents, two delipidation methods, and introduction of a fractionation step based on different protein solubility in surfactants, were evaluated. When using efficient zwitterionic detergents (3-[(3-cholamidopropyl)dimethylamino]-1-propanesulfonate, CHAPS; amidosulfobetaine 14, ASB-14), the patterns obtained by direct loading of total extracts were qualitatively overlapping with patterns obtained from fractionated samples. In contrast, a weaker nonionic agent (Nonidet P-40, NP-40) produced a different protein pattern in the collected fractions. Delipidation did not improve the results for all the different extraction methods. Immunoblots performed with antibodies recognizing cytosolic and membrane-spanning proteins, which were detected as nondegraded spots, showed that membrane proteins with intermediate molecular mass could be recovered. We suggest, as a simple and efficient method for preparing rat brain maps, the homogenization in a solution containing an efficient zwitterionic surfactant, which allows to solubilize cytosolic and membrane proteins in a single step. Alternatively, a fractionation can be carried out on samples homogenized by a weak solubilizing agent, a more labor-intensive effort resulting in a larger number of proteins on two maps. [source] Solid-State Photodimerization of Guest Molecules in Inclusion CompoundsEUROPEAN JOURNAL OF ORGANIC CHEMISTRY, Issue 18 2006Irena Zouev Abstract Photochemical dimerization reactions of 1,3-diphenyl-1-propen-3-one (chalcone), 9-acetylanthracene, and 9-(methoxycarbonyl)anthracene as guest molecules in inclusion compounds with 1,1,6,6-tetraphenyl-2,4-hexadiyne-1,6-diol were studied. The irradiation of a single crystal containing chalcone was carried out in a single step and resulted in a single crystal containing the photodimer in full occupancy. In the case of the crystal containing 9-acetylanthracene, X-ray diffraction data were collected after irradiation for different periods of time. Only one of the two crystallographically independent pairs of 9-acetylanthracene underwent solid-state photodimerization at ca. 11,% conversion to the head-to-tail dimer. Photodimerization of the 9-(methoxycarbonyl)anthracene inclusion compound led, after irradiation for 2.5 h, to ca. 37,% conversion. It was found that the molecules that were arranged in stacks had undergone photodimerization in two different ways, so that on the average it looked as if all the guest molecules had polymerized. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2006) [source] A Graphene Oxide,Streptavidin Complex for Biorecognition , Towards Affinity PurificationADVANCED FUNCTIONAL MATERIALS, Issue 17 2010Zunfeng Liu Abstract In our postgenomic era, understanding of protein-protein interactions by characterizing the structure of the corresponding protein complex is becoming increasingly important. An important problem is that many protein complexes are only stable for a few minutes. Dissociation will occur when using the typical, time-consuming purification methods such as tandem affinity purification and multiple chromatographic separations. Therefore, there is an urgent need for a quick and efficient protein-complex purification method for 3D structure characterization. The graphene oxide (GO)·streptavidin complex is prepared via a GO·biotin·streptavidin strategy and used for affinity purification. The complex shows a strong biotin recognition capability and an excellent loading capacity. Capturing biotinylated DNA, fluorophores and Au nanoparticles on the GO·streptavidin complexes demonstrates the usefulness of the GO·streptavidin complex as a docking matrix for affinity purification. GO shows a high transparency towards electron beams, making it specifically well suited for direct imaging by electron microscopy. The captured protein complex can be separated via a filtration process or even via on-grid purification and used directly for single-particle analysis via cryo-electron microscopy. Therefore, the purification, sample preparation, and characterization are rolled into one single step. [source] The Synthesis, Characterisation, and Reactivity of Some Polydentate Phosphinoamine Ligands with Benzene-1,3-diyl and Pyridine-2,6-diyl BackbonesHELVETICA CHIMICA ACTA, Issue 10 2003Nermin Biricik The polydentate phosphinoamines 1,3-{(Ph2P)2N}2C6H4 and 2,6-{(Ph2P)2N}2C5H3N have been prepared in a single step from the reaction of the amines 1,3-(NH2)2C6H4 or 2,6-(NH2)2C5H3N with Ph2PCl in presence of Et3N (1,:,4,:,4 molar ratio) in CH2Cl2. Reaction of 1,3-{(Ph2P)2N}2C6H4 or 2,6-{(Ph2P)2N}2C5H3N with elemental sulfur or selenium in CH2Cl2 affords the corresponding tetrasulfide or tetraselenide, respectively, in good yield. The complexes [1,3-{Mo(CO)4(Ph2P)2N}2(C6H4)] and [2,6-{Mo(CO)4(Ph2P)2N}2(C5H3N)] were prepared from the reaction of these phosphinoamines with [Mo(CO)4(nbd)] (nbd=norbornadiene) in toluene, and the structure of the latter complex has been determined by single-crystal X-ray diffraction analysis. [source] One-Step Direct-Patterning Template Utilizing Self-Assembly of POSS-Containing Block CopolymersADVANCED MATERIALS, Issue 43 2009Tomoyasu Hirai We report the self-assembly of organic-inorganic block copolymers (BCP) in thin-films by simple solvent annealing on unmodified substrates. The resulting vertically oriented lamellae and cylinders are converted to a hard silica mask by a single step highly selective oxygen plasma etching. The size of the resulting nanostructures in the case of cylinders is less than 10,nm. [source] Nanostructured Organic,Inorganic Composite Materials by Twin Polymerization of Hybrid MonomersADVANCED MATERIALS, Issue 20 2009Stefan Spange Abstract Forming two structurally different but associated polymer structures in a single step is a possible route for the production of nanostructured materials. By means of twin polymerization of specially constructed monomers consisting of two different covalently bonded building blocks (hybrid monomers), this route is realized. What is important is that two different macromolecular structures are formed from one monomer in a single process. The two polymers formed can be linear, branched, or cross-linked structures. The molecular composition of the hybrid monomer defines the degree of cross-linking of the corresponding macromolecular structures that is theoretically possible. [source] Generalized trapezoidal numerical integration of an advanced soil modelINTERNATIONAL JOURNAL FOR NUMERICAL AND ANALYTICAL METHODS IN GEOMECHANICS, Issue 1 2008Yunming Yang Abstract This paper investigates the numerical performance of the generalized trapezoidal integration rule by using an advanced soil model. The generalized trapezoidal integration rule can include many other integration algorithms by adjusting a single parameter , ranging from 1 to 0. The soil model used is the recently developed middle surface concept (MSC) sand model which simulates different soil response characteristics by using different pseudo-yield functions. The generalized trapezoidal rule and MSC sand model are used to simulate the responses of sand samples with different relative densities under various initial and loading conditions. Instead of a single step, multiple loading steps bring the sample to the vicinity of failure. These comprehensive investigations examine and compare the influences of various values of , on the numerical solution of integrated constitutive equations, the convergence of Newton's iterative scheme, and the integration accuracy. Copyright © 2007 John Wiley & Sons, Ltd. [source] A unified approach for the formulation of interaction problems by the boundary element methodINTERNATIONAL JOURNAL FOR NUMERICAL METHODS IN ENGINEERING, Issue 5 2006Yalcín Mengi Abstract A unified formulation is presented, based on boundary element method, in a form suitable for performing the interaction analyses by substructure method for solid,solid and soil,structure problems. The proposed formulation permits the evaluation of all the elements of impedance and input motion matrices simultaneously at a single step in terms of system matrices of the boundary element method without solving any special problem, such as, unit displacement or load problem, as required in conventional methods. It eliminates further the complicated procedure and the need for using scattering analysis in the evaluation of input motion functions. To explain the formulation, it is first given for an inclusion interacting with an infinite surrounding medium under the influence of a seismic input, where both the inclusion and surrounding medium are treated as viscoelastic. It is shown that the formulation for a rigid inclusion may be obtained from that for flexible inclusion as a special case through a transformation. Then, the formulation is extended to other types of interaction problems: a multi-inclusion problem and an interaction problem involving a foundation embedded in a viscoelastic half-space. It is found that the proposed formulation remains essentially the same for all kinds of interaction problems and it can be used not only in regular interaction analysis, but also in the analysis involving diffraction of waves in a medium containing holes. Copyright © 2005 John Wiley & Sons, Ltd. [source] Titania/Polypyrrole Hybrid Nanocomposites Built from In-Situ Generated Organically Functionalized Nanoanatase Building Blocks,ADVANCED MATERIALS, Issue 3 2003S. Roux A bifunctional capping ligand is used to obtain pyrrol-functionalized monodispersed nanocrystalline TiO2 (anatase) particles in a single step. The pyrrole functionalities in the shell are then (electro)chemically polymerized to create a polypyrrole (PPy)/TiO2 hybrid nanocomposite film (see Figure). Further electronic modification of the conducting polymer is possible, leading to a great variety of potential applications. [source] One Step Synthesis of Chiral Olefins via Asymmetric Diamination and their Applications as Ligands for Rhodium(I)-Catalyzed 1,4-AdditionsADVANCED SYNTHESIS & CATALYSIS (PREVIOUSLY: JOURNAL FUER PRAKTISCHE CHEMIE), Issue 4 2010Xichao Hu Abstract A variety of acyclic chiral dienes were synthesized in a single step via palladium(0)-catalyzed asymmetric allylic and homoallylic CH diamination of terminal olefins. The applications of such simple dienes as steering ligands for rhodium(I)-catalyzed asymmetric 1,4-additions afforded the corresponding adducts in excellent yields and up to 85% ee. [source] A Novel Bis-Thiourea Organocatalyst for the Asymmetric Aza-Henry ReactionADVANCED SYNTHESIS & CATALYSIS (PREVIOUSLY: JOURNAL FUER PRAKTISCHE CHEMIE), Issue 11-12 2008Constantinos Rampalakos Abstract A novel bis-thiourea/2,2,-diaminobinaphthalene (BINAM)-based catalyst for the asymmetric aza-Henry reaction has been developed. This catalyst promotes the reaction of N -Boc imines with nitroalkanes to afford ,-nitroamines with good yields and high enantioselectivities. This catalyst has the advantage that it can be prepared in a single step from commercially available materials. A model is proposed for the catalyst action where both components of the reaction are activated simultaneously by hydrogen bonding. Regardless of the mechanism, the success of the present catalyst demonstrates the potential of bis-thioureas as an interesting class of relatively unexplored catalysts. [source] 2,3-Disubstituted Benzo[b]thiophenes from Diarylalkynes via Electrophilic Addition-Cyclization and Palladium-Catalyzed Cross-CouplingADVANCED SYNTHESIS & CATALYSIS (PREVIOUSLY: JOURNAL FUER PRAKTISCHE CHEMIE), Issue 13 2007Giuseppe Lamanna Abstract Diarylalkynes are readily transformed in 3-chlorobenzo[b]thiophenes in a two-step electrophilic addition-cyclization procedure that runs highly efficiently in solution or in the solid phase. The heteroaromatic carbon-chlorine bond participates in palladium-catalyzed Suzuki,Miyaura or Buchwald,Hartwig cross-couplings to give, in a single step, 2,3-disubstituted derivatives of pharmacological relevance . [source] One-Pot Conversion of Cephalosporin C to 7-Aminocephalosporanic Acid in the Absence of Hydrogen PeroxideADVANCED SYNTHESIS & CATALYSIS (PREVIOUSLY: JOURNAL FUER PRAKTISCHE CHEMIE), Issue 14 2005Fernando Lopez-Gallego Abstract The main drawback in the production of 7-aminocephalosporanic acid (7-ACA) at the industrial level is the inactivation of the enzymes implicated in the process due to the presence of hydrogen peroxide during the reaction. As an alternative, we have developed the conversion of cephalosporin C to 7-ACA in a single reactor without the presence of hydrogen peroxide during the reaction, achieving more than 80% yield. In order to develop this process, D -amino acid oxidase (DAAO) was co-immobilized with catalase (CAT), which is able to fully eliminate in situ the hydrogen peroxide formed by the neighbouring DAAO molecules. Thus, the product of the reaction is only ,-ketoadipyl-7-ACA. This system prevents the inactivation of the oxidase by hydrogen peroxide, solving the main problem of the enzymatic process. Moreover, we have found that ,-ketoadipyl-7-ACA is recognized as a substrate by glutaryl acylase (GAC) and hydrolyzed as long as glutaric acid is absent from the reaction medium (because it is able to inhibit the hydrolysis). The low stability of ,-ketoadipyl-7-ACA justifies the use of a single reactor, in which glutaryl acylase is already present when this substrate is generated. Thus, the whole process may (and must) be performed in a single step, and in the absence of hydrogen peroxide that could affect the stabilities of the involved enzymes. [source] Electrospun self-assembled nanofiber yarnsJOURNAL OF APPLIED POLYMER SCIENCE, Issue 1 2008Abhijit Mondal Abstract A technique for making self-assembled electrospun (E-spun) nanofiber yarns from poly(acrylonitrile) in a single step is described. The process involved formation of the nanofiber yarn directly within the electrospinning zone and its removal before it can reach the counter-electrode. The yarn is presumably formed due to splitting of the main jet into numerous nanojets and their reassembly into a single entity midway between the two electrodes. The process was found to occur at a particular field strength, which varied considerably with the concentration of the polymer dope. The gross morphology of yarns and the alignment of nanofibers in the yarn were evaluated by scanning electron microscopy (SEM). The rationale behind the formation of the yarn like structure has been explained. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008 [source] Catalytic selective oxidation faces the sustainability challenge: turning points, objectives reached, old approaches revisited and solutions still requiring further investigationJOURNAL OF CHEMICAL TECHNOLOGY & BIOTECHNOLOGY, Issue 9 2010Fabrizio Cavani Abstract This review documents some examples of recently developed technologies and new approaches currently being investigated in the field of catalytic selective oxidation, that may contribute to improving the sustainability of the chemical industry. Tools to reach this ambitious target include process integration, the development of new reactions for the valorization of renewables and new catalysts able to perform complex transformations in a single step. Copyright © 2010 Society of Chemical Industry [source] Expression of 2 Lipomyces kononenkoae,-Amylase Genes in Selected Whisky Yeast StrainsJOURNAL OF FOOD SCIENCE, Issue 7 2004K. la Grange-Nel ABSTRACT: Nineteen whisky yeasts were evaluated according to their fermentation performance and ability to produce a palatable spirit. Four of these strains were selected and, together with a commercial wine yeast strain (control), were transformed with integration plasmids containing the LKA1 and LKA2 , -amylase genes from the yeast Lipomyces kononenkoae. Fermentation trials with starch-containing media indicated that the transformants produced between 47% and 66% of the theoretical ethanol yield. This study has resulted in progress toward the development of whisky yeast that could ultimately be used in a process during which production of amylases, hydrolysis of starch, and fermentation of resulting sugars to grain whisky occur in a single step. [source] Synthesis of models of metabolites: Oxidation of variously substituted chromenes including acronycine, by a porphyrin catalytic systemJOURNAL OF HETEROCYCLIC CHEMISTRY, Issue 7 2005Bernardin Akagah The influence of chemical neighbouring on oxidation of substituted 2,2-dimethylchromenes derivatives 5-8 by a biomimetic catalytic system was first studied. It was then applied to acronycine an anti-cancer drug in order to obtain in one single step oxidized products resulting from the reactivity of the 1,2-double bond in the pyranic D-ring. These 2,2-dimethylchromenes constitute the structural moiety responsible for the activity of acronycine. This oxidation showed the sensitivity of the ethylenic bond, leading to the formation of the corresponding epoxides, diols and/or ketoalcohol. In the case of 5-dimethylamino-2,2-dimethylchromene 8, the double bond was not sensitive to oxidation, but the N -methyl groups reacted to lead to the formamide derivative 16 and an imino-alcohol 17. This methodology applied to acronycine molecule 1, allowed to obtain in one step, two oxidized compounds, a trans -diol 3 and a ketoalcohol 4 under preparative conditions. [source] Gas-phase ion chemistry in the ternary silane,propyne,phosphine systemJOURNAL OF MASS SPECTROMETRY (INCORP BIOLOGICAL MASS SPECTROMETRY), Issue 6 2004Lorenza Operti Abstract The gas-phase ion chemistry of propyne,phosphine and silane,propyne,phosphine mixtures was studied by ion trap mass spectrometry. For the binary mixture, the effect of different partial pressures of the reagents on the yield of C and P-containing ions was evaluated. Reaction sequences and rate constants were determined and reaction efficiencies were calculated from comparison of experimental and collisional rate constants. In the ternary silane,propyne,phosphine systems, the reaction pathways leading to formation of SimCnPpHq+ ions were determined and the rate constants of the most important steps were measured. For some ion species, selected by double isolation procedures (MS/MS), the low ion abundances prevented determination of the reaction rate constants. Si, C and P-containing ions are mainly produced in reactions of SimPpHq+ ions with propyne, while the reactivity of the SimCnHq+ ions towards PH3 and of the CnPpHq+ ions towards SiH4 is very low. The formation of hydrogenated SiCP ions is interesting for their possible role as precursors of amorphous silicon carbides doped with phosphorus, obtained in a single step, by deposition from properly activated silane,propyne,phosphine mixtures. Copyright © 2004 John Wiley & Sons, Ltd. [source] Grafting polymer chains bearing an N -succinimidyl activated ester end-group onto primary amine-coated silica particles and application of a simple, one-step approach via nitroxide-mediated controlled/living free-radical polymerizationJOURNAL OF POLYMER SCIENCE (IN TWO SECTIONS), Issue 1 2010Julien Parvole Abstract In a first part, the alkoxyamine initiator derived from BlocBuilder® based on the nitroxide SG1 and bearing an N -succinimidyl ester function was used to synthesize a variety of well-defined polymers with the activated ester group at the ,-end. The grafting of those polymer chains onto primary-amine functionalized Stöber silica particles was performed in soft conditions at room temperature and was studied as a function of the polymer chain length, the type of solvent, and the concentrations of both polymer and amine. Polymer grafting densities were mainly in the 0.1,0.2 chain nm,2 range. To increase the grafting density in simple experimental conditions, a direct one-step method was then proposed: the primary-amine modified silica, the N -succinimidyl ester functionalized alkoxyamine, and the monomer were all introduced into the reaction medium at once. This technique allowed grafting and chain growth to take place simultaneously at the polymerization temperature (i.e., 120 °C for styrene), in a single step, and produced hybrid particles with very high grafting density, up to 0.9 chain nm,2, and long polymer chains. © 2009 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 48: 173,185, 2010 [source] Selective polymerization of functional monomers with Novozym 435JOURNAL OF POLYMER SCIENCE (IN TWO SECTIONS), Issue 24 2007Martijn A. J. Veld Abstract Two novel monomers, ambrettolide epoxide and isopropyl aleuriteate, encompassing functional groups, were obtained in a single step from commercially available materials. Novozym 435 catalyzed ring opening polymerization of ambrettolide epoxide furnished a polymer of Mn = 9.7 kg/mol and PDI = 1.9 while the epoxide groups remained unaffected during the polymerization. Selective polymerization of the primary hydroxyl groups of isopropyl aleuriteate using Novozym 435 was feasible and a polymer with moderate molecular weight (Mn = 5.6 kg/mol, PDI = 3.2) was isolated in moderate yield (43%). Subsequently, copolymerization of isopropyl aleuriteate with ,-CL in different ratios was performed, resulting in soluble, hydroxy functional polymers with good molecular weights (Mn = 10.4,27.2 kg/mol) in good yield (71,78%). The secondary hydroxy groups in the polymer reacted easily with hexyl isocyanate, showing the potential of isopropyl aleuriteate as a comonomer for the synthesis of functional polyesters. © 2007 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 45: 5968,5978, 2007 [source] Determination of basic azaarenes in aviation kerosene by solid-phase extraction and HPLC-fluorescence detectionJOURNAL OF SEPARATION SCIENCE, JSS, Issue 12 2009Elaine Rocha da Luz Abstract SPE in combination with HPLC and fluorescence detection has been used for sensitive determination of six basic azaarenes (7,8-benzoquinoline, 7,9-dimethylbenz[c]acridine, 9-amino-1,2,3,4-tetrahydroacridine, 9-methylacridine, acridine, and dibenz[a,j]acridine) in aviation kerosene (jet fuel). SPE was performed in a single step using a strong cation exchange sorbent. The HPLC system consisted of C18 column with a selected detection program of optimal ,exc and ,em. A gradient elution with ACN and phosphate buffer (pH 6.5) at a flow rate of 1 mL/min allowed efficient and fast separation of azaarenes within 15 min. The LOD and LOQ values (S/N ratio 3:1 and 10:1, respectively) were between 0.0013 and 0.021 and from 0.0044 to 0.072 ng per injection. The calibration curves showed linear behavior from the LOQ to 250 ,g/L (r2 >0.99). For the spiked concentration of 6.0 ,g/L, recoveries were from 92 to 107% for jet fuel samples, except for 9-amino-1,2,3,4-tetrahydroacridine, which presented 68% recovery. The proposed method was applied to the quantification of those six basic azaarenes in one commercial kerosene and in three aviation kerosene samples. The presence of 7,8-benzoquinoline (up to 3.2 ,g/L) and dibenzo[a,j]acridine (up to 6.3 ,g/L) was confirmed in aviation kerosene. [source] Preparation of nitrocellulose (NC) immuno-affinity membrane for purification of rAPC antibodyJOURNAL OF SEPARATION SCIENCE, JSS, Issue 6-7 2008Haixiang Sun Abstract In this study, recombinant allophycocyanin (rAPC) with a purity of 98% was transferred from a gel to a nitrocellulose (NC) membrane to develop a simple and efficient immuno-affinity membrane. Atomic force microscopy (AFM) was used to investigate the surface topography of the affinity membrane and its characterization indicated that rAPC easily forms trimers or hexamers on the membrane surface on use of the given transfer method. The hydrodynamic radius (Rh) of the rAPC aggregation was equal to 103 nm or 365 nm according to dynamic light scattering (DLS), which was in agreement with the result obtained by AFM. Based on the specific immunological reaction of antigen and antibody, anti-APC antibodies were purified from rabbit polyclonal serum in a single step. The amount of absorbed antibody was 5.79 mg/g membrane according to analysis by ELISA methods. The purity of antibodies was up to 98% according to SDS-PAGE. The adsorption-desorption cycle of rAPC was repeated six times using the same immuno-affinity membrane, and there was no significant loss in adsorption capacity. The method provides a novel and efficient immunological affinity membrane for the purification of antibodies. [source] Pyrene-Functionalised, Alternating Copolyimide for Sensing Nitroaromatic CompoundsMACROMOLECULAR RAPID COMMUNICATIONS, Issue 6 2009Stefano Burattini Abstract A novel, pyrene-functionalised copolymer has been synthesised in a single step via imidisation of poly(maleic anhydride- alt -1-octadecene) with 1-pyrenemethylamine, and its potential for the detection of volatile nitro aromatic compounds (NACs) evaluated. The new copolymer forms complexes in solution with NACs such as 2,5-dinitrobenzonitrile, as shown by 1H NMR, UV-vis and fluorescence spectroscopy. Moreover, thin films of this copolymer, cast from THF solution, undergo almost instantaneous fluorescence quenching when exposed to the vapour of 2,5-dinitrobenzonitrile (a model for TNT) at ambient temperatures and pressures. [source] Purification of Escherichia coli RNA polymerase using a self-cleaving elastin-like polypeptide tagPROTEIN SCIENCE, Issue 6 2010Baley A. Fong Abstract A self-cleaving elastin-like polypeptide (ELP) tag was used to purify the multisubunit Escherichia coli RNA polymerase (RNAP) via a simple, nonchromatographic method. To accomplish this, the RNAP , subunit was tagged with a self-cleaving ELP-intein tag and coexpressed with the ,, ,,, and , subunits. The assembled RNAP was purified with its associated subunits, and was active and acquired at reasonable yield and purity. To remove residual polynucleotides bound to the purified RNAP, two polymer precipitation methods were investigated: polyethyleneimine (PEI) and polyethylene (PEG) precipitation. The PEG procedure was shown to enhance purity and was compatible with downstream ELP-intein purification. Thus, this simple ELP-based method should be applicable for the nonchromatographic purification of other recombinant, in vivo -assembled multisubunit complexes in a single step. Further, the simplicity and low cost of this method will likely facilitate scale up for large-scale production of additional multimeric protein targets. Finally, this technique may have utility in isolating protein interaction partners that associate with a given target. [source] Increasing high-throughput Discovery bioanalysis using automated selected reaction monitoring compound optimization, ultra-high-pressure liquid chromatography, and single-step sample preparation workflowsRAPID COMMUNICATIONS IN MASS SPECTROMETRY, Issue 21 2009James Smalley QuickQuan is an integrated software package for Thermo Scientific triple quadrupole mass spectrometers that allows users to automate routine operations ranging from method development to data processing. QuickQuan automated optimization of compound-selected reaction monitoring (SRM) transitions by evaluating both positive and negative polarities during an infusion. Whichever mode produces the most intense Q1 scan is then carried to product ion spectra. QuickQuan then writes these SRM methods to a shared network database. The total volume of compound needed is 100,µL infused over approximately 1.6,min. The auto-optimization is carried out in 96-well plates and does not require an operator present. The SRM database was shared between two identical TSQ Quantum mass spectrometers. For data acquisition, QuickQuan automatically created a sequence file complete with a data processing method pre-populated with compound IDs and corresponding SRM transitions. To increase throughput we coupled each Finnigan Quantum with ultra-high-pressure liquid chromatography (uHPLC) accomplished using 4× Ultra Flux quaternary pumps that were designed to handle pressures up to 15 000,psi. The total run time for all analyses was 1.2,min using BEH 1.7,µm particle C18 columns. Further time reductions were realized with sample preparation accomplished using Strata Impact protein precipitation plates which provided an in-well protein crash and 0.20 micron filtering in a one-step process. Pharmacokinetic data turnaround time was significantly improved by combining these three techniques of automated method development with the speed efficiency of uHPLC and a single step in well sample preparation. Copyright © 2009 John Wiley & Sons, Ltd. [source] A prospective study of the time to evacuate acute subdural and extradural haematomas,ANAESTHESIA, Issue 3 2009D. Bulters Summary We performed a prospective, single-centre study of times to treatment of patients with life-threatening, traumatic, extra- and subdural haematomas requiring surgical evacuation between May 2006 and May 2007. The mean time to surgical decompression was 5.0 h and 32% were performed within 4 h. Patients who initially presented to a district hospital and required transfer for neurosurgery were decompressed in 5.4 h vs 3.7 h for those admitted directly. The current standard of surgical evacuation of all haematomas within 4 h is not being met. Delays were identified in every stage in the management of these patients and no single step was identified as the major cause. Initial treatment in district hospitals led to delays greater than the added driving time. There may be time savings from carrying out treatment steps in parallel instead of in series. [source] Einstein Lecture , Passion for precision,ANNALEN DER PHYSIK, Issue 9 2006T.W. Hänsch Abstract Optical frequency combs from mode-locked femtosecond lasers have link optical and microwave frequencies in a single step, and they provide the long missing clockwork for optical atomic clocks. By extending the limits of time and frequency metrology, they enable new tests of fundamental physics laws. Precise comparisons of optical resonance frequencies of atomic hydrogen and other atoms with the microwave frequency of a cesium atomic clock are establishing sensitive limits for possible slow variations of fundamental constants. Optical high harmonic generation is extending frequency comb techniques into the extreme ultraviolet, opening a new spectral territory to precision laser spectroscopy. Frequency comb techniques are also providing a key to attosecond science by offering control of the electric field of ultrafast laser pulses. In our laboratories at Stanford and Garching, the development of new instruments and techniques for precision laser spectroscopy has long been motivated by the goal of ever higher resolution and measurement accuracy in optical spectroscopy of the simple hydrogen atom which permits unique confrontations between experiment and fundamental theory. This lecture recounts these adventures and the evolution of laser frequency comb techniques from my personal perspective. [source] A sensitive and specific liquid chromatography/tandem mass spectrometry method for determination of echinacoside and its pharmacokinetic application in ratsBIOMEDICAL CHROMATOGRAPHY, Issue 6 2009Hao Yang Abstract A rapid and sensitive method based on liquid chromatography/tandem mass spectrometry (LC/MS/MS) for the determination of echinacoside in rat plasma was established and fully validated. A single step of liquid,liquid extraction with n -butanol was utilized. Chromatographic separation of the analyte and the internal standard (IS), chlorogenic acid, from the sample matrix was performed using a Capcell-MG C18 analytical column (100 2.0 mm × 5 µm), with a gradient of acetonitrile and water containing 0.1% acetic acid as the mobile phase. Detection was performed on a triple quadrupole tandem mass spectrometer equipped with electrospray ionization source operated in negative ion selected reaction monitoring mode. The method was linear in the concentration range 10,2500 ng/mL. The deviations of both intra- and inter-day precisions (RSD) were 7.1% and the assay accuracies were within 99.2,106.5%. Echinacoside proved to be stable during sample storage, preparation and analysis when an antioxidant solution was used. The method was successfully applied to a pharmacokinetic study in rats after an intragastric administration of echinacoside (100 mg/kg). With the lower limit of quantification at 10 ng/mL, this method proved to have sufficient selectivity, sensitivity and reproducibility for the pharmacokinetic study of echinacoside. Copyright © 2009 John Wiley & Sons, Ltd. [source] | |||||||||||||||||||||||||||||||||||||