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Sample records for 2-methylpropane

  1. Viscosities of binary mixtures of toluene with butan-1-ol and 2-methylpropan-2-ol

    Directory of Open Access Journals (Sweden)

    VASILE DUMITRESCU

    2005-11-01

    Full Text Available The viscosities of binary liquid mixtures of toluene with butan-1-ol and 2-methylpropan-2-ol have been determined at 298.15, 303.15, 308.15, 313.15 and 318.15 K over the whole concentration range. The Hind, Grunberg–Nissan, Wijk, Auslander and McAllister models were used to calculate the viscosity coefficients and these were compared with the experimental data for the mixtures. Excess viscosities were also calculated and fitted to the Redlich–Kister equation. Various thermodynamic properties of viscous flow activation were determined and their variations with composition are discussed.

  2. Measurements and thermodynamic modeling of liquid-liquid equilibria in ternary system 2-methoxy-2-methylpropane+p-cresol+water☆

    Institute of Scientific and Technical Information of China (English)

    Liejin Luo; Dong Liu; Libo Li; Yun Chen

    2016-01-01

    Liquid–liquid equilibrium (LLE) data for the ternary system 2-methoxy-2-methylpropane (methyl tert-butyl ether)+p-cresol+water was measured at atmospheric pressure and temperatures of 298.15 K and 313.15 K. From the distribution coefficients and selectivity, it was found that 2-methoxy-2-methylpropane is an efficient solvent to extract p-cresol from wastewater. The consistency of the experimental tie-line data was verified with the Hand and Bachman equations. These data were also correlated with the non-random two liquid (NRTL) and universal quasi-chemical correlation activity coefficient (UNIQUAC) models to yield binary interac-tion parameters for p-cresol extraction process evaluation. Both models agreed with experiments very well, yet the NRTL model showed even smal er average deviation than the UNIQUAC model.

  3. Contribution to study of the thermodynamics properties of mixtures containing 2-methoxy-2-methylpropane, alkanol, alkane

    International Nuclear Information System (INIS)

    Graphical abstract: - Highlights: • Experimental enthalpies for the mixtures MTBE + pentanol + hexane and pentanol + hexane were measured. • No experimental ternary values were found in the currently available literature. • Excess molar enthalpies are positive over the whole range of composition. • The ternary contribution is also positive with the exception of a range located around the rich compositions of 1-pentanol. - Abstract: Excess molar enthalpies for the ternary system {x1 2-methoxy-2-methylpropane (MTBE) + x2 1-pentanol + (1 − x1 − x2) hexane} and the involved binary mixture {x 1-pentanol + (1 − x) hexane}, have been measured at T = 298.15 K and atmospheric pressure over the whole composition range. We are not aware of the existence of previous experimental measurement of the excess enthalpy for the ternary mixture under study in the literature currently available. Values of the excess molar enthalpies were measured using a Calvet microcalorimeter. The results were fitted by means of different variable degree polynomials. The ternary contribution to the excess enthalpy was correlated with the equation due to Verdes et al. (2004), and the equation proposed by Myers–Scott (1963) was used to fit the experimental binary mixture measured in this work. Smooth representations of the results are presented and used to construct constant excess molar enthalpy contours on Roozeboom diagrams. The excess molar enthalpies for the binary and ternary system are positive over the whole range of composition. The binary mixture {x 1-pentanol + (1 − x) hexane} is asymmetric, with its maximum displace toward a high mole fraction of decane. The ternary contribution is also positive with the exception of a range located around the rich compositions of 1-pentanol, and the representation is asymmetric. Additionally, the group contribution model of the UNIFAC model, in the versions of Larsen et al. (1987) [18] and Gmehling et al. (1993) [19] was used to estimate

  4. Synthesis and Evaluation of Poly(Sodium 2-Acrylamido-2-Methylpropane Sulfonate-co-Styrene/Magnetite Nanoparticle Composites as Corrosion Inhibitors for Steel

    Directory of Open Access Journals (Sweden)

    Gamal A. El-Mahdy

    2014-01-01

    Full Text Available Self-stabilized magnetic polymeric composite nanoparticles of coated poly-(sodium 2-acrylamido-2-methylpropane sulfonate-co-styrene/magnetite (PAMPS-Na-co-St/Fe3O4 were prepared by emulsifier-free miniemulsion polymerization using styrene (St as a monomer, 2-acrylamido-2-methylpropane sulfonic acid sodium salt (AMPS-Na as an ionic comonomer, N,N-methylenebisacrylamide (MBA as crosslinker, hexadecane (HD as a hydrophobic solvent, and 2,2-azodiisobutyronitrile (AIBN as an initiator in the presence of hydrophobic oleic acid coated magnetite particles. Hydrophobic oleic acid coated magnetite particles with an average size of about 7-10 nm were prepared with the new modified water-based magnetite ferrofluid, synthesized by a chemical modified coprecipitation method. The morphology and the particle size distributions of the crosslinked PAMPS-Na-co-St/Fe3O4 composite were observed and analyzed by transmission electron microscopy (TEM. The average Fe3O4 content of PAMPS-Na-co-St/Fe3O4 was determined by thermogravimetric analysis (TGA. The inhibitory action of PAMPS-Na-co-St/Fe3O4 towards steel corrosion in 1 M HCl solutions has been investigated by polarization and electrochemical impedance spectroscopy (EIS methods. Polarization measurements indicate that PAMPS-Na-co-St/Fe3O4 acts as a mixed type-inhibitor and the inhibition efficiency increases with inhibitor concentration. The results of potentiodynamic polarization and EIS measurements clearly showed that the inhibition mechanism involves blocking of the steel surface by inhibitor molecules via adsorption.

  5. Synthesis and evaluation of poly(Sodium 2-Acrylamido-2-Methylpropane Sulfonate-co-Styrene)/magnetite nanoparticle composites as corrosion inhibitors for steel.

    Science.gov (United States)

    El-Mahdy, Gamal A; Atta, Ayman M; Al-Lohedan, Hamad A

    2014-01-30

    Self-stabilized magnetic polymeric composite nanoparticles of coated poly-(sodium 2-acrylamido-2-methylpropane sulfonate-co-styrene)/magnetite (PAMPS-Na-co-St/Fe3O4) were prepared by emulsifier-free miniemulsion polymerization using styrene (St) as a monomer, 2-acrylamido-2-methylpropane sulfonic acid sodium salt (AMPS-Na) as an ionic comonomer, N,N-methylenebisacrylamide (MBA) as crosslinker, hexadecane (HD) as a hydrophobic solvent, and 2,2-azodiisobutyronitrile (AIBN) as an initiator in the presence of hydrophobic oleic acid coated magnetite particles. Hydrophobic oleic acid coated magnetite particles with an average size of about 7-10 nm were prepared with the new modified water-based magnetite ferrofluid, synthesized by a chemical modified coprecipitation method. The morphology and the particle size distributions of the crosslinked PAMPS-Na-co-St/Fe3O4 composite were observed and analyzed by transmission electron microscopy (TEM). The average Fe3O4 content of PAMPS-Na-co-St/Fe3O4 was determined by thermogravimetric analysis (TGA). The inhibitory action of PAMPS-Na-co-St/Fe3O4 towards steel corrosion in 1 M HCl solutions has been investigated by polarization and electrochemical impedance spectroscopy (EIS) methods. Polarization measurements indicate that PAMPS-Na-co-St/Fe3O4 acts as a mixed type-inhibitor and the inhibition efficiency increases with inhibitor concentration. The results of potentiodynamic polarization and EIS measurements clearly showed that the inhibition mechanism involves blocking of the steel surface by inhibitor molecules via adsorption.

  6. Synthesis and evaluation of poly(Sodium 2-Acrylamido-2-Methylpropane Sulfonate-co-Styrene)/magnetite nanoparticle composites as corrosion inhibitors for steel.

    Science.gov (United States)

    El-Mahdy, Gamal A; Atta, Ayman M; Al-Lohedan, Hamad A

    2014-01-01

    Self-stabilized magnetic polymeric composite nanoparticles of coated poly-(sodium 2-acrylamido-2-methylpropane sulfonate-co-styrene)/magnetite (PAMPS-Na-co-St/Fe3O4) were prepared by emulsifier-free miniemulsion polymerization using styrene (St) as a monomer, 2-acrylamido-2-methylpropane sulfonic acid sodium salt (AMPS-Na) as an ionic comonomer, N,N-methylenebisacrylamide (MBA) as crosslinker, hexadecane (HD) as a hydrophobic solvent, and 2,2-azodiisobutyronitrile (AIBN) as an initiator in the presence of hydrophobic oleic acid coated magnetite particles. Hydrophobic oleic acid coated magnetite particles with an average size of about 7-10 nm were prepared with the new modified water-based magnetite ferrofluid, synthesized by a chemical modified coprecipitation method. The morphology and the particle size distributions of the crosslinked PAMPS-Na-co-St/Fe3O4 composite were observed and analyzed by transmission electron microscopy (TEM). The average Fe3O4 content of PAMPS-Na-co-St/Fe3O4 was determined by thermogravimetric analysis (TGA). The inhibitory action of PAMPS-Na-co-St/Fe3O4 towards steel corrosion in 1 M HCl solutions has been investigated by polarization and electrochemical impedance spectroscopy (EIS) methods. Polarization measurements indicate that PAMPS-Na-co-St/Fe3O4 acts as a mixed type-inhibitor and the inhibition efficiency increases with inhibitor concentration. The results of potentiodynamic polarization and EIS measurements clearly showed that the inhibition mechanism involves blocking of the steel surface by inhibitor molecules via adsorption. PMID:24487568

  7. Excess enthalpies from displacement calorimetry excess enthalpies for 1,1,1- trichloroethane+carbon tetrachloride and 2-chloro-2-methylpropane+carbon tetrachloride at 298.15 K

    NARCIS (Netherlands)

    Miltenburg, J.C. van der; Obbink, J.H.; Meijer, E.L.

    1979-01-01

    Excess enthalpies HE are reported for the 1,1,1-trichloroethane+carbon tetrachloride and 2-chloro-2-methylpropane+carbon tetrachloride systems. The results are fitted to the formula HE = x(1−x)Σiai(1−2x)i.

  8. Biocompatibility of polypropylene non-woven fabric membrane via UV-induced graft polymerization of 2-acrylamido-2-methylpropane sulfonic acid

    Energy Technology Data Exchange (ETDEWEB)

    Song Lingjie [State Key Laboratory of Polymer Physics and Chemistry, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun 130022 (China); Graduate University of Chinese Academy of Sciences, Beijing 100049 (China); Zhao Jie; Yang Huawei; Jin Jing; Li Xiaomeng [State Key Laboratory of Polymer Physics and Chemistry, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun 130022 (China); Stagnaro, Paola [Istituto per Io Studio delle Macromolecole, Consiglio Nazionale delle Ricerche, Via de Marini 6, 16149 Genova (Italy); Yin Jinghua, E-mail: yinjh@ciac.jl.cn [State Key Laboratory of Polymer Physics and Chemistry, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun 130022 (China)

    2011-10-15

    This work described the graft polymerization of a sulfonic acid terminated monomer, 2-acrylamido-2-methylpropane sulfonic acid (AMPS), onto the surface of polypropylene non-woven (NWF PP) membrane by O{sub 2} plasma pretreatment and UV-induced photografting method. The chemical structure and composition of the modified surfaces were analyzed by FTIR-ATR and XPS, respectively. The wettability was investigated by water contact angle and equilibrium water adsorption. And the biocompatibility of the modified NWF PP membranes was evaluated by protein adsorption and platelet adhesion. It was found that the graft density increased with prolonging UV irradiation time and increasing AMPS concentration; the water contact angles of the membranes decreased from 124{sup o} to 26{sup o} with the increasing grafting density of poly(AMPS) from 0 to 884.2 {mu}g cm{sup -2}, while the equilibrium water adsorption raised from 5 wt% to 75 wt%; the protein absorption was effectively suppressed with the introduction of poly(AMPS) even at the low grafting density (132.4 {mu}g cm{sup -2}); the number of platelets adhering to the modified membrane was dramatically reduced when compared with that on its virgin surface. These results indicated that surface modification of NWF PP membrane with AMPS was a facile approach to construct biocompatible surface.

  9. Solubility of n-butane and 2-methylpropane (isobutane) in 1-alkyl-3-methylimidazolium-based ionic liquids with linear and branched alkyl side-chains.

    Science.gov (United States)

    Pison, Laure; Shimizu, Karina; Tamas, George; Lopes, José Nuno Canongia; Quitevis, Edward L; Gomes, Margarida F Costa

    2015-11-11

    The solubility of n-butane and 2-methylpropane (isobutane) in three ionic liquids - 1-(2-methylpropyl)-3-methylimidazolium bis(trifluoromethylsulfonyl)imide [(2mC3)C1im][Ntf2], 1-(3-methylbutyl)-3-methylimidazolium bis(trifluoromethylsulfonyl)imide [(3mC4)C1im][Ntf2] and 1-methyl-3-pentylimidazolium bis(trifluoromethylsulfonyl)imide [C5C1im][Ntf2] - has been measured at atmospheric pressure from 303 to 343 K. Isobutane is less soluble than n-butane in all the ionic liquids. Henry's constant values range from 13.8 × 10(5) Pa for n-butane in [C5C1im][Ntf2] at 303 K to 64.5 × 10(5) Pa for isobutane in [(2mC3)C1im][Ntf2] at 343 K. The difference in solubility between the two gases can be explained by a more negative enthalpy of solvation for n-butane. A structural analysis of the pure solvents and of the solutions of the gases, probed by molecular dynamics simulations, could explain the differences found in the systems: (i) the nonpolar domains of the ionic liquids accommodate better the long and more flexible n-butane solute; (ii) the small differences in solubility of each gas in the ionic liquids with the same number of carbon atoms in the alkyl side-chains are explained by the absence of large structural differences in the pure solvents. In all cases, the structural analysis of the four ionic liquids confirms that the studied gases can act as probes of the molecular structure of the ionic liquids, the simulations being always compatible with the experimental solubility data.

  10. 2-Methylpropan-2-aminium 2-(methoxycarbonylbenzoate

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    Jian Li

    2011-10-01

    Full Text Available In the title compound, C4H12N+·C9H7O4−, two C atoms and the N atom of the cation lie on a mirror plane, while all the atoms of the anion are disordered about a mirror plane. In the crystal, N—H...O hydrogen bonds link the components into chains along [010]. In the anion, the mean planes of the methoxycarbonyl and carboxylate groups form dihedral angles of 83.0 (2 and 83.2 (2°, respectively, with the aromatic ring.

  11. C4H9I 2-Iodo-2-methylpropane

    Science.gov (United States)

    Demaison, J.

    This document is part of Subvolume C 'Symmetric Top Molecules' of Volume 29 'Molecular Constants Mostly from Microwave, Molecular Beam, and Sub-Doppler Laser Spectroscopy' of Landolt-Börnstein - Group II 'Molecules and Radicals'.

  12. Synthesis and Characterization of Graft Copolymer of Dextran and 2-Acrylamido-2-methylpropane Sulphonic Acid

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    Venkanna Azmeera

    2012-01-01

    Full Text Available A novel biodegradable graft copolymer of dextran (Dx and 2-acrylamido-2-methyl-1-propane sulphonic acid (AMPS was synthesized by grafting poly-AMPS chains onto dextran backbone by free radical polymerization using ceric ammonium nitrate (CAN as an initiator. Different amounts of AMPS were used to synthesize four different grades of graft copolymers with different side chain lengths. These grafted polymers were characterized by elemental analysis, FTIR, 1HNMR, rheological technique, scanning electron microscopy (SEM, thermogravimetric analysis (TGA, and X-ray diffractometry (XRD. They exhibited efficient flocculation performance in kaolin suspension.

  13. (SS,2S,3S-2-(2-Methylpropan-2-sulfinamido-3-phenylbutyronitrile

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    Klaus Harms

    2009-11-01

    Full Text Available The absolute configuration has been determined for the title compound, C14H20N2OS. There are two independent molecules in the asymmetric unit. Intermolecular N—H...O hydrogen bonds are observed in the crystal packing, forming infinite chains with the base vectors [100] and [010]. Each chain contains only one of the two independent molecules.

  14. Bis{(R-N-[(R-2-benzyloxy-1-(4-tert-butylphenylethyl]-2-methylpropane-2-sulfinamide} monohydrate

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    Charlotte L. Humes

    2014-04-01

    Full Text Available The asymmetric unit of the title compound, 2C23H33NO2S·H2O, contains one organic molecule in a general position and one co-crystallized water molecule on a crystallographic twofold axis. Each water molecule serves as a hydrogen-bond donor to a pair of S=O acceptors on symmetry-related molecules. Thus, each trio of molecules forms one title formula unit. These groupings are further connected along [010] via weak non-classical C—H...O hydrogen bonds.

  15. Preparation and characterization of poly(2-acrylamido-2-methylpropane-sulfonic acid)/Chitosan hydrogel using gamma irradiation and its application in wastewater treatment

    Science.gov (United States)

    Gad, Y. H.

    2008-09-01

    Radiation grafting of chitosan with 2-acrylamido-2-methyl propane sulfonic acid (AMPS) has been successfully performed. The effect of absorbed dose (kGy) and the chitosan:AMPS ratio on graft hydrogelization was studied. The structure of the prepared hydrogel was confirmed using infrared spectroscopy (IR). Thermal properties were simultaneously studied by thermogravimetric analysis (TGA). The effect of the polymerization variables on the swelling % of the prepared hydrogel was investigated. The highest equilibrium degree of swelling (38.6 g/g) and gel % (94.7%) of the prepared chitosan-AMPS hydrogel was at 40% AMPS and absorbed dose of 10 kGy. The removal of methylene blue, acid red dye, Cd (II) and Cr (III) from composed wastewater was also investigated. The effect of pH, the chitosan:AMPS ratio and the concentration of the pollutant on the adsorption process were studied.

  16. Debaryomyces hansenii strains differ in their production of flavor compounds in a cheese-surface model

    DEFF Research Database (Denmark)

    Gori, Klaus; Sørensen, Louise Marie; Petersen, Mikael Agerlin;

    2012-01-01

    important cheese flavor compounds, primarily branched-chain aldehydes and alcohols, and thus important for the final cheese flavor. Quantification of representative aldehydes (2-Methylpropanal, 3-Methylbutanal) and alcohols (2-Methyl-1-propanol, 3-Methyl-1-butanol, and 3-Methyl-3-buten-1-ol) showed...... that the investigated D. hansenii strains varied significantly with respect to production of these flavor compounds. Contrary to the alcohols (2-Methyl-1-propanol,3-Methyl-1-butanol, and3-Methyl-3-buten-1-ol), the aldehydes (2-Methylpropanal, 3-Methylbutanal) were produced by the D. hansenii strains in concentrations...

  17. Metabolite production and kinetics of branched-chain aldehyde oxidation in Staphylococcus xylosus

    DEFF Research Database (Denmark)

    Beck, Hans Christian; Hansen, A.M.; Lauritsen, F.R.

    2002-01-01

    ,5-methylpyrazine, 2-phenylethylacetate, 2-methyltetrahydrothiophen-3-one, 3-(methylthio)-propanoic acid and 3-(methylthio)-propanal. The organoleptic metabolites derived from branched-chain amino acid catabolism; 2-methylpropanal from valine, 2-methylbutanal from isoleucine and 3-methylbutanal from leucine were...

  18. CARBONYL STRETCHING FREQUENCY-CHARACTERISTICS FOR THE STRONGLY HYDROPHOBIC SOLUTE, N-CYCLOHEXYL-2-PYRROLIDONE IN BINARY AQUEOUS MIXTURES AT 298.15-K - EVIDENCE FOR A 2-DOMAIN MODEL FOR 2-BUTOXYETHANOL WATER MIXTURES

    NARCIS (Netherlands)

    ENGBERTS, JBFN; PERJESSY, A; BLANDAMER, MJ; EATON, G

    1992-01-01

    Infrared spectra are reported in the C=O stretching region for N-cyclohexyl-2-pyrrolidone (NCP) in D2O as a function of the mole fraction of added cosolvents. As the solvent composition is changed by adding methanol, ethanol and 2-methylpropan-2-ol, the spectra reveal the presence of two types of hy

  19. [Fe(mu-btzmp)(2)(btzmp)(2)](ClO4)(2) : a doubly-bridged 1D spin-transition bistetrazole-based polymer showing thermal hysteresis behaviour

    NARCIS (Netherlands)

    Quesada, Manuel; Kooijman, Huub; Gamez, Patrick; Costa, Jose Sanchez; van Koningsbruggen, Petra J.; Weinberger, Peter; Reissner, Michael; Spek, Anthony L.; Haasnoot, Jaap G.; Reedijk, Jan

    2007-01-01

    The reaction of btzmp (1,2-bis(tetrazol-1-yl)-2-methylpropane) with Fe(ClO4)(2) generates a 1D polymeric species, [Fe(mu-btzmp)(2)(btzmp)(2)](ClO4)(2), showing a steep spin transition (T-1/2 up arrow = 136 K and T-1/2 down arrow = 133 K) with a 3 K thermal hysteresis. The crystal structure at 100 an

  20. Intermolecular Hydrogen Transfer in Isobutane Hydrate

    OpenAIRE

    Takeshi Sugahara; Kei Takeya; Mikio Nakagoshi; Takashi Minami; Atsushi Tani; Naohiro Kobayashi; Kazunari Ohgaki

    2012-01-01

    Electron spin resonance (ESR) spectra of butyl radicals induced with γ-ray irradiation in the simple isobutane (2-methylpropane) hydrate (prepared with deuterated water) were investigated. Isothermal annealing results of the γ-ray-irradiated isobutane hydrate reveal that the isobutyl radical in a large cage withdraws a hydrogen atom from the isobutane molecule through shared hexagonal-faces of adjacent large cages. During this “hydrogen picking” process, the isobutyl radical is apparently tra...

  1. Determination of some volatile compounds in fruit spirits produced from grapes (Vitis Vinifera L.) and plums (Prunus domestica L.) cultivars

    OpenAIRE

    Kostik, Vesna; Gjorgjeska, Biljana; Angelovska, Bistra; Kovacevska, Ivona

    2014-01-01

    Fruit spirits contain a large array of volatile compounds among which the important role from toxicological aspect besides ethanol has methanol, aliphatic esters and fusel alcohols. This study evaluates the content of ethanol, ethyl acetate, methanol, isopropyl alcohol (2-propanol), n-propyl alcohol (propan-l-ol), isobutyl alcohol (2-methylpropan-1-ol), n-butyl alcohol (1-butanol), isoamyl alcohol (3-methyl-1-butanol) and n-amyl alcohol (pentan-1-ol) in different grapes and plum brandies i...

  2. Discovery of novel (4-piperidinyl)-piperazines as potent and orally active acetyl-CoA carboxylase 1/2 non-selective inhibitors: F-Boc and triF-Boc groups are acid-stable bioisosteres for the Boc group.

    Science.gov (United States)

    Chonan, Tomomichi; Wakasugi, Daisuke; Yamamoto, Daisuke; Yashiro, Miyoko; Oi, Takahiro; Tanaka, Hiroaki; Ohoka-Sugita, Ayumi; Io, Fusayo; Koretsune, Hiroko; Hiratate, Akira

    2011-03-01

    Novel (4-piperidinyl)-piperazine derivatives were synthesized and evaluated as ACC1/2 non-selective inhibitors. Optimization of the substituents on the nitrogen of the piperidine ring led to the identification of the fluorine substituted tert-butoxycarbonyl group. Advanced analog, 1,1,1-trifluoro-2-methylpropan-2-yl 4-{4-[(2-amino-6-methyl-1-benzothiophen-3-yl)carbonyl]piperazin-1-yl}piperidine-1-carboxylate (12c) showed potent inhibitory activities in enzyme-assay and cell-based assays. Compound 12c also exhibited reduction of hepatic de novo fatty acid synthesis in rats after oral administration.

  3. Protection of Petroleum Pipeline Carbon Steel Alloys with New Modified Core-Shell Magnetite Nanogel against Corrosion in Acidic Medium

    Directory of Open Access Journals (Sweden)

    Gamal A. El Mahdy

    2013-01-01

    Full Text Available New method was used to prepare magnetite nanoparticle based on reduction of Fe(III ions with potassium iodide to produce Fe3O4 nanoparticle. The prepared magnetite was stabilized with cross-linked polymer based on 2-acrylamido-2-methylpropane sulfonic acid (AMPS to prepare novel core-shell nanogel. In this respect, Fe3O4/poly(2-acrylamido-2-methylpropane sulfonic acid (PAMPS magnetic nanogels with controllable particle size produced via free aqueous polymerization at 65°C have been developed for the first time. The polymer was crosslinked in the presence of N,N-methylenebisacrylamide (MBA as a crosslinker and potassium peroxydisulfate (KPS as redox initiator system. The structure and morphology of the magnetic nanogel were characterized by Fourier transform infrared spectroscopy (FTIR and transmission and scanning electron microscopy (TEM and SEM. The effectiveness of the synthesized compounds as corrosion inhibitors for carbon steel in 1 M HCl was investigated by various electrochemical techniques such as potentiodynamic polarization and electrochemical impedance spectroscopy (EIS. The results showed enhancement in inhibition efficiencies with increasing the inhibitor concentrations. The results showed that the nanogel particles act as mixed inhibitors. EIS data revealed that Rct increases with increasing inhibitor concentration.

  4. Novel negatively-charged membrane adsorbers made using combination of photopolymerization and immersion precipitation

    Directory of Open Access Journals (Sweden)

    Tomković Tanja

    2016-01-01

    Full Text Available A novel method combining a traditional immersion precipitation process for making membranes with photopolymerization and crosslinking of functional monomers included in the casting solution was used to prepare asymmetric polyethersulfone membranes with submicron particles incorporating glycidyl methacrylate copolymer. In order to introduce sulfonic groups epoxide rings of glycidyl methacrylate were opened using two methods. The first method was functionalization with sodium sulfite, and the second method was functionalization with sulfuric acid and then grafting with 2-acrylamido-2-methylpropane sulfonic acid. Obtained membranes were characterized using infrared spectroscopy, conductometric titration and water permeability measurements. Scanning electron microscopy and atomic force microscopy were used to investigate the surface morphology and topology of membrane. Dynamic adsorption of Rhodamine B as a model dye was used to demonstrate suitability of these novel membranes for membrane adsorption since the adsorption capacity for dye cations was much better for both functionalized membrane with sodium sulfite and grafted membrane with 2-acrylamido-2-methylpropane sulfonic acid compared to the nonfunctionalized membrane. [Projekat Ministarstva nauke Republike Srbije, br. TR32008 and III 43009

  5. Structure-guided engineering of Lactococcus lactis alcohol dehydrogenase LlAdhA for improved conversion of isobutyraldehyde to isobutanol

    KAUST Repository

    Liu, Xiang

    2013-03-01

    We have determined the X-ray crystal structures of the NADH-dependent alcohol dehydrogenase LlAdhA from Lactococcus lactis and its laboratory-evolved variant LlAdhA(RE1) at 1.9Å and 2.5Å resolution, respectively. LlAdhA(RE1), which contains three amino acid mutations (Y50F, I212T, and L264V), was engineered to increase the microbial production of isobutanol (2-methylpropan-1-ol) from isobutyraldehyde (2-methylpropanal). Structural comparison of LlAdhA and LlAdhA(RE1) indicates that the enhanced activity on isobutyraldehyde stems from increases in the protein\\'s active site size, hydrophobicity, and substrate access. Further structure-guided mutagenesis generated a quadruple mutant (Y50F/N110S/I212T/L264V), whose KM for isobutyraldehyde is ∼17-fold lower and catalytic efficiency (kcat/KM) is ∼160-fold higher than wild-type LlAdhA. Combining detailed structural information and directed evolution, we have achieved significant improvements in non-native alcohol dehydrogenase activity that will facilitate the production of next-generation fuels such as isobutanol from renewable resources.

  6. Producing Radical-Free Hyperpolarized Perfusion Agents for In Vivo Magnetic Resonance Using Spin-Labeled Thermoresponsive Hydrogel.

    Science.gov (United States)

    Cheng, Tian; Mishkovsky, Mor; Junk, Matthias J N; Münnemann, Kerstin; Comment, Arnaud

    2016-07-01

    Dissolution dynamic nuclear polarization (DNP) provides a way to tremendously improve the sensitivity of nuclear magnetic resonance experiments. Once the spins are hyperpolarized by dissolution DNP, the radicals used as polarizing agents become undesirable since their presence is an additional source of nuclear spin relaxation and their toxicity might be an issue. This study demonstrates the feasibility of preparing a hyperpolarized [1-(13) C]2-methylpropan-2-ol (tert-butanol) solution free of persistent radicals by using spin-labeled thermoresponsive hydrophilic polymer networks as polarizing agents. The hyperpolarized (13) C signal can be detected for up to 5 min before the spins fully relax to their thermal equilibrium. This approach extends the applicability of spin-labeled thermoresponsive hydrogel to the dissolution DNP field and highlights its potential as polarizing agent for preparing neat slowly relaxing contrast agents. The hydrogels are especially suited to hyperpolarize deuterated alcohols which can be used for in vivo perfusion imaging. PMID:27184565

  7. The separation and analysis of symmetric and asymmetric dimethylarginine and other hydrophilic isobaric compounds using aqueous normal phase chromatography.

    Science.gov (United States)

    Pesek, Joseph J; Matyksa, Maria T; Modereger, Brent; Hasbun, Alejandra; Phan, Vy T; Mehr, Zahra; Guzman, Mariano; Watanable, Seiichiro

    2016-04-01

    Two biologically important compounds with clinical relevance, asymmetric dimethylarginine and symmetric dimethylarginine, are analyzed using aqueous normal phase chromatography on silica hydride-based columns. Two different stationary phases were tested, a commercially available Diamond Hydride™ and a 2-acrylamido-2-methylpropane sulfonic acid experimental column. Two types of analytical protocols were investigated: analysis of the compounds when separation was achieved and analysis of the compounds with partial chromatographic separation. Urine samples from tuberculosis patients were tested for levels of asymmetric and symmetric dimethylarginine. The mass spectrometric technique of in-source fragmentation that can provide data similar to a tandem mass analyzer was evaluated as a means of identification and quantitation of the two compounds when complete separation is not achieved. This same protocol was also evaluated for two other isobaric compounds, glucose-1 and glucose-6 phohsphate, and leucine and isoleucine.

  8. Characterization of the most odor-active compounds of Iberian ham headspace.

    Science.gov (United States)

    Carrapiso, Ana I; Ventanas, Jesús; García, Carmen

    2002-03-27

    Gas chromatography-olfactometry (GC-O) based on detection frequency (DF) was used to characterize the most odor-active compounds from the headspace of Iberian ham. Twenty-eight odorants were identified by GC-O on two capillary columns, including aldehydes (11), sulfur-containing compounds (7), ketones (5), nitrogen-containing compounds (2), esters (2), and an alcohol. Among them, the highest odor potencies (DF values) were found for 2-methyl-3-furanthiol, 2-heptanone, 3-methylbutanal, methanethiol, hexanal, hydrogen sulfide, 1-penten-3-one, 2-methylpropanal, ethyl 2-methylbutyrate, and (E)-2-hexenal. Nine of the 28 most odor-active compounds were identified for the first time as aroma components of dry-cured ham, including hydrogen sulfide, 1-penten-3-one, (Z)-3-hexenal, 1-octen-3-one, and the meaty-smelling compounds 2-methyl-3-furanthiol, 2-furfurylthiol, 3-mercapto-2-pentanone, 2-acetyl-1-pyrroline, and 2-propionyl-1-pyrroline.

  9. Thermodynamic and acoustical properties of mixtures p-anisaldehyde—alkanols (C1-C4)—2-methyl-1-propanol at 303.15 K

    Science.gov (United States)

    Saini, Balwinder; Kumar, Ashwani; Rani, Ruby; Bamezai, Rajinder K.

    2016-07-01

    The density, viscosity and speed of sound of pure p-anisaldehyde and some alkanols, for example, methanol, ethanol, propan-1-ol, propan-2-ol, butan-1-ol, butan-2-ol, 2-methylpropan-1-ol, and the binary mixtures of p-anisaldehyde with these alkanols were measured over the entire composition range at 303.15 K. From the experimental data, various thermodynamic parameters such as excess molar volume ( V E), excess Gibbs free energy of activation (Δ G*E), and deviation parameters like viscosity (Δη), speed of sound (Δ u), isentropic compressibility (Δκs), are calculated. The excess as well as deviation parameters are fitted to Redlich—Kister equation. Additionally, the viscosity data for the systems has been used to correlate the application of empirical relation given by Grunberg and Nissan, Katti and Chaudhari, and Hind et al. The results are discussed in terms of specific interactions present in the mixtures.

  10. Separation of PCR-ready DNA from dairy products using magnetic hydrophilic microspheres and poly(ethylene glycol)-NaCl water solutions

    Energy Technology Data Exchange (ETDEWEB)

    Rittich, Bohuslav [Masaryk University, Faculty of Science, Institute of Experimental Biology, Tvrdeho 14, CZ-611 37 Brno (Czech Republic); Brno University of Technology, Faculty of Chemistry, Institute of Food Science and Biotechnology, Purkynova 464/118, CZ-612 00 Brno (Czech Republic)], E-mail: rittich@sci.muni.cz; Spanova, Alena [Masaryk University, Faculty of Science, Institute of Experimental Biology, Tvrdeho 14, CZ-611 37 Brno (Czech Republic); Brno University of Technology, Faculty of Chemistry, Institute of Food Science and Biotechnology, Purkynova 464/118, CZ-612 00 Brno (Czech Republic); Salek, Petr [Brno University of Technology, Faculty of Chemistry, Institute of Food Science and Biotechnology, Purkynova 464/118, CZ-612 00 Brno (Czech Republic); Nemcova, Petra [Masaryk University, Faculty of Science, Institute of Experimental Biology, Tvrdeho 14, CZ-611 37 Brno (Czech Republic); Trachtova, Stepanka [Brno University of Technology, Faculty of Chemistry, Institute of Food Science and Biotechnology, Purkynova 464/118, CZ-612 00 Brno (Czech Republic); Horak, Daniel [Institute of Macromolecular Chemistry, Academy of Sciences of the Czech Republic, Heyrovsky Sq. 2, CZ-162 06 Prague (Czech Republic)

    2009-05-15

    Carboxyl group-containing magnetic nonporous poly(2-hydroxyethyl methacrylate-co-glycidyl methacrylate) (P(HEMA-co-GMA)) and magnetic glass microspheres were used for the isolation of bacterial DNA. P(HEMA-co-GMA) microspheres were prepared by the dispersion polymerization in toluene/2-methylpropan-1-ol mixture in the presence of magnetite nanoparticles obtained by coprecipitation of Fe(II) and Fe(III) salts with ammonium hydroxide. Carboxyl groups were then introduced by oxidation of the microspheres with potassium permanganate. The most extensive DNA recovery was achieved at PEG 6000 concentrations of 12% or 16% and 2 M NaCl. The method proposed was used for bacterial DNA isolation from different dairy products containing Bifidobacterium and Lactobacillus cells. The presence of target DNA and the quality of isolated DNA were checked by polymerase chain reaction (PCR) amplification with specific primers.

  11. Fluorinated Alkoxide-Based Magnesium-Ion Battery Electrolytes that Demonstrate Li-Ion-Battery-Like High Anodic Stability and Solution Conductivity.

    Science.gov (United States)

    Crowe, Adam J; Stringham, Kyle K; Bartlett, Bart M

    2016-09-01

    Based on DFT predictions, a series of highly soluble fluorinated alkoxide-based electrolytes were prepared, examined electrochemically, and reversibly cycled. The alcohols react with ethylmagnesium chloride to generate a fluoroalkoxy-magnesium chloride intermediate, which subsequently reacts with aluminum chloride to generate the electrolyte. Solutions starting from a 1,1,1,3,3,3-hexafluoro-2-methylpropan-2-ol precursor exhibit high anodic stability, 3.2 V vs Mg(2+/0), and a record 3.5 mS/cm solution conductivity. Excellent galvanostatic cycling and capacity retention (94%) is observed with more than 300 h of cycle time while employing the standard Chevrel phase-Mo6S8 cathode material.

  12. Polymerization of novel methacrylated anthraquinone dyes

    Directory of Open Access Journals (Sweden)

    Christian Dollendorf

    2013-02-01

    Full Text Available A new series of polymerizable methacrylated anthraquinone dyes has been synthesized by nucleophilic aromatic substitution reactions and subsequent methacrylation. Thereby, green 5,8-bis(4-(2-methacryloxyethylphenylamino-1,4-dihydroxyanthraquinone (2, blue 1,4-bis(4-((2-methacryloxyethyloxyphenylaminoanthraquinone (6 and red 1-((2-methacryloxy-1,1-dimethylethylaminoanthraquinone (12, as well as 1-((1,3-dimethacryloxy-2-methylpropan-2-ylaminoanthraquinone (15 were obtained. By mixing of these brilliant dyes in different ratios and concentrations, a broad color spectrum can be generated. After methacrylation, the monomeric dyes can be covalently emplaced into several copolymers. Due to two polymerizable functionalities, they can act as cross-linking agents. Thus, diffusion out of the polymer can be avoided, which increases the physiological compatibility and makes the dyes promising compounds for medical applications, such as iris implants.

  13. Separation of PCR-ready DNA from dairy products using magnetic hydrophilic microspheres and poly(ethylene glycol)-NaCl water solutions

    International Nuclear Information System (INIS)

    Carboxyl group-containing magnetic nonporous poly(2-hydroxyethyl methacrylate-co-glycidyl methacrylate) (P(HEMA-co-GMA)) and magnetic glass microspheres were used for the isolation of bacterial DNA. P(HEMA-co-GMA) microspheres were prepared by the dispersion polymerization in toluene/2-methylpropan-1-ol mixture in the presence of magnetite nanoparticles obtained by coprecipitation of Fe(II) and Fe(III) salts with ammonium hydroxide. Carboxyl groups were then introduced by oxidation of the microspheres with potassium permanganate. The most extensive DNA recovery was achieved at PEG 6000 concentrations of 12% or 16% and 2 M NaCl. The method proposed was used for bacterial DNA isolation from different dairy products containing Bifidobacterium and Lactobacillus cells. The presence of target DNA and the quality of isolated DNA were checked by polymerase chain reaction (PCR) amplification with specific primers.

  14. Scientific Opinion on the safety and efficacy of branched-chain primary aliphatic alcohols/aldehydes/acids, acetals and esters with esters containing branched-chain alcohols and acetals containing branched-chain aldehydes (chemical group 2 when used as flavourings for all animal species

    Directory of Open Access Journals (Sweden)

    EFSA Panel on Additives and Products or Substances used in Animal Feed (FEEDAP

    2012-10-01

    Full Text Available

    Chemical group 2 consists of branched-chain primary aliphatic alcohols/aldehydes/acids, acetals and esters with esters containing branched-chain alcohols and acetals containing branched-chain aldehydes, of which 34 are currently authorised for use as flavours in food. The use of 2-methylpropionic acid, isopentyl acetate, 3-methylbutyl butyrate and 2-methylbutyl acetate is safe at the proposed use level of 25 mg/kg complete feed for cattle, salmonids and non food producing animals and at 5 mg/kg complete feed for pigs and poultry. 2-Methylpropan-1-ol, isopentanol, 2-ethylhexan-1-ol, 2-methylpropanal, 3-methylbutanal, 2-methylbutyraldehyde, 3-methylbutyric acid, 2-methylvaleric acid, 2-ethylbutyric acid, 2-methylbutyric acid, 2-methylheptanoic acid, 4-methyloctanoic acid, isobutyl acetate, isobutyl butyrate, 3-methylbutyl propionate, 3-methylbutyl formate, glyceryl tributyrate, isobutyl isobutyrate, isopentyl isobutyrate, isobutyl isovalerate, isopentyl 2-methylbutyrate, 2-methylbutyl isovalerate and 2-methylbutyl butyrate are safe at the proposed use level of 5 mg/kg complete feed for all animal species. 3,7-Dimethyloctan-1-ol, 2-methylundecanal, 4-methylnonanoic acid, 3-methylbutyl hexanoate, 3-methylbutyl dodecanoate, 3-methylbutyl octanoate and 3-methylbutyl 3-methylbutyrate are safe at a maximum of 1.5 mg/kg complete feed for cattle, salmonids and non food-producing animals and of 1.0 mg/kg complete feed for pigs and poultry. No safety concern was identified for the consumer from the use of these compounds up to the highest safe level in feedingstuffs for all animal species. All compounds should be considered as irritants to skin, eyes and respiratory tract, and as skin sensitisers. The compounds do not pose a risk to the environment when used at concentrations considered safe for the target species. Since all compounds are used in food as flavourings, no further demonstration of efficacy is necessary.

  15. Scientific Opinion on the safety and efficacy of aliphatic and aromatic mono- and di-thiols and mono-, di-, tri-, and polysulphides with or without additional oxygenated functional groups (chemical group 20 when used as flavourings for all animal species

    Directory of Open Access Journals (Sweden)

    EFSA Panel on Additives and Products or Substances used in Animal Feed (FEEDAP

    2013-05-01

    Full Text Available Chemical group 20 consists of aliphatic and aromatic mono- and di-thiols and mono-, di-, tri-, and polysulphides with or without additional oxygenated functional groups, of which 31 are currently authorised for use as flavours in food. The FEEDAP Panel was unable to perform an assessment of six compounds (methanethiol, methyl propyl disulphide, dipropyl trisulphide, 3-mercaptobutan-2-one, 3-(methylthiobutanal and 3-methyl-1,2,4-trithiane because of issues related to the purity of the compounds. The FEEDAP Panel concludes that the following 25 compounds are safe for the target species at the proposed maximum dose level (0.05 mg/kg complete feed: 3-(methylthiopropionaldehyde, methyl 3-(methylthiopropionate, allylthiol, dimethyl sulphide, dibutyl sulphide, diallyl disulphide, diallyl trisulphide, dimethyl trisulphide, dipropyl disulphide, allyl isothiocyanate, dimethyl disulphide, 2-methylbenzene-1-thiol, S-methyl butanethioate, allyl methyl disulphide, 3-(methylthiopropan-1-ol, 3-(methylthiohexan-1-ol, 1-propane-1-thiol, diallyl sulphide, 2,4-dithiapentane, 2-methyl-2-(methyldithiopropanal, 2-methylpropane-1-thiol, methylsulfinylmethane, propane-2-thiol, 3,5-dimethyl-1,2,4-trithiolane and 2-methyl-4-propyl-1,3-oxathiane. No safety concern for the consumer would arise from the use of these 25 compounds of CG 20 up to the highest safe level in feedingstuffs for all animal species, with the exception of allyl isothiocyanate. Although additional exposure to this substance through its low use level in animal feeds would not substantially increase consumer exposure, the FEEDAP Panel notes that the estimated exposure of consumers is already higher than the acceptable daily intake (ADI. All compounds should be considered irritant to skin, eyes and respiratory tract and as skin sensitisers. The proposed concentration of 0.05 mg flavour/kg feed is not expected to cause detrimental effects to the environment, except for 2-methylpropane-1-thiol, for which 0

  16. γ-Unsaturated aldehydes as potential Lilial replacers.

    Science.gov (United States)

    Schroeder, Martin; Mathys, Marion; Ehrensperger, Nadja; Büchel, Michelle

    2014-10-01

    A series of Claisen rearrangements was undertaken in order to find a replacement for Lilial (=3-(4-(tert-butyl)phenyl)-2-methylpropanal), a high-tonnage perfumery ingredient with a lily-of-the-valley odour, which is a CMR2 material [1]. 5,7,7-Trimethyl-4-methyleneoctanal (10), the synthesis of which is described, became the main lead. It possesses an odour which is very close to that of Lilial but lacks its substantivity. Aldehydes with higher molecular weights than that of 10 were, therefore, synthesised in order to boost substantivity and to understand the structural requirements for a 'Lilial' odour. The aldehydes were obtained via Claisen rearrangements of 'exo-methylidene' vinyl ethers, allenyl vinyl ethers, or allenyl allyl ethers. Alternatively, coupling of terminal alkynes with allyl alcohols led to the desired aldehydes. Derivatives of 10 and their sila analogues were also synthesised. The olfactory properties of all synthesised molecules were evaluated for possible structure-odour relationships (SOR). PMID:25329790

  17. Characterization of the key aroma compounds in an american bourbon whisky by quantitative measurements, aroma recombination, and omission studies.

    Science.gov (United States)

    Poisson, Luigi; Schieberle, Peter

    2008-07-23

    Thirty-one of the 45 odor-active compounds previously identified by us in an American Bourbon whisky were quantified by stable isotope dilution assays. Also for this purpose, new synthetic pathways were developed for the synthesis of the deuterium-labeled whisky lactone as well as for gamma-nona- and gamma-decalactone. To obtain the odor activity values (OAVs), the concentrations measured were divided by the odor thresholds of the odorants determined in water/ethanol (6:4 by vol.). Twenty-six aroma compounds showed OAVs >1, among which ethanol, ethyl (S)-2-methylbutanoate, 3-methylbutanal, 4-hydroxy-3-methoxybenzaldehyde, (E)-beta-damascenone, ethyl hexanoate, ethyl butanoate, ethyl octanoate, 2-methylpropanal, (3S,4S)- cis-whiskylactone, (E, E)-2,4-decadienal, 4-allyl-2-methoxyphenol, ethyl-3-methylbutanoate, and ethyl 2-methylpropanoate showed the highest values. The overall aroma of the Bourbon whisky could be mimicked by an aroma recombinate consisting of the 26 key odorants in their actual concentrations in whisky using water/ethanol (6:4 by vol.) as the matrix. Omission experiments corroborated the importance of, in particular, 4-hydroxy-3-methoxybenzaldehyde, (3S,4S)-cis-whiskylactone, ethanol, and the entire group of esters for the overall aroma of the Bourbon whisky. PMID:18582086

  18. Characterization of the key aroma compounds in an american bourbon whisky by quantitative measurements, aroma recombination, and omission studies.

    Science.gov (United States)

    Poisson, Luigi; Schieberle, Peter

    2008-07-23

    Thirty-one of the 45 odor-active compounds previously identified by us in an American Bourbon whisky were quantified by stable isotope dilution assays. Also for this purpose, new synthetic pathways were developed for the synthesis of the deuterium-labeled whisky lactone as well as for gamma-nona- and gamma-decalactone. To obtain the odor activity values (OAVs), the concentrations measured were divided by the odor thresholds of the odorants determined in water/ethanol (6:4 by vol.). Twenty-six aroma compounds showed OAVs >1, among which ethanol, ethyl (S)-2-methylbutanoate, 3-methylbutanal, 4-hydroxy-3-methoxybenzaldehyde, (E)-beta-damascenone, ethyl hexanoate, ethyl butanoate, ethyl octanoate, 2-methylpropanal, (3S,4S)- cis-whiskylactone, (E, E)-2,4-decadienal, 4-allyl-2-methoxyphenol, ethyl-3-methylbutanoate, and ethyl 2-methylpropanoate showed the highest values. The overall aroma of the Bourbon whisky could be mimicked by an aroma recombinate consisting of the 26 key odorants in their actual concentrations in whisky using water/ethanol (6:4 by vol.) as the matrix. Omission experiments corroborated the importance of, in particular, 4-hydroxy-3-methoxybenzaldehyde, (3S,4S)-cis-whiskylactone, ethanol, and the entire group of esters for the overall aroma of the Bourbon whisky.

  19. A flow reactor study of neopentane oxidation at 8 atmospheres: Experiments and modeling

    Energy Technology Data Exchange (ETDEWEB)

    Wang, S.; Miller, D.L.; Cernansky, N.P. [Drexel Univ., Philadelphia, PA (United States). Dept. of Mechanical Engineering and Mechanics; Curran, H.J.; Pitz, W.J.; Westbrook, C.K. [Lawrence Livermore National Lab., CA (United States)

    1999-08-01

    An existing detailed chemical kinetic reaction mechanism for neopentane oxidation is applied to new experimental measurements, taken in a flow reactor operating at a pressure of 8 atm. The reactor temperature ranged from 620 K to 810 K and flow rates of the reactant gases neopentane, oxygen, and nitrogen were 0.285, 7.6, and 137.1 standard liter per minute (SLM), respectively, producing an equivalence ratio of 0.3. Initial simulations identified some deficiencies in the existing model and the paper presents modifications which included upgrading the thermodynamic parameters of alkyl radical and alkylperoxy radical species, adding an alternative isomerization reaction of hydroperoxy-neopentyl-peroxy, and a multistep reaction sequence for 2-methylpropan-2-yl radical with molecular oxygen. These changes improved the calculation for the overall reactivity and the concentration profiles of the following primary products: formaldehyde, acetone, isobutene; 3,3-dimethyloxetane, methacrolein, carbon monoxide, carbon dioxide, and water. Experiments indicate that neopentane shows negative temperature coefficient behavior similar to other alkanes, though it is not as pronounced as that shown by n-pentane for example. Modeling results indicate that this behavior is caused by the {beta}-scission of the neopentyl radical and the chain propagation reactions of the hydroperoxyl-neopentyl radical.

  20. A chemical assessment of the suitability of allyl- iso-propyltelluride as a Te precursor for metal organic vapour phase epitaxy

    Science.gov (United States)

    Hails, Janet E.; Cole-Hamilton, David J.; Stevenson, John; Bell, William; Foster, Douglas F.; Ellis, David

    2001-04-01

    The chemical studies, which led to the testing of allyl- iso-propyltelluride (allylTePr i) as a Te precursor in metal organic vapour phase epitaxy are presented. The pyrolysis in hydrogen of allylTePr i gave products including 1,5-hexadiene, propane and propene. Co-pyrolysis of dimethylcadmium (Me 2Cd) and allylTePr i gave the hydrocarbons expected from the pyrolysis of the individual precursors plus additional hydrocarbons including 2-methylpropane and 1-butene. Plots of percentage decomposition versus temperature, which proved extremely useful in determining the likely growth temperatures for both CdTe and HgTe, showed that allylTePr i is less stable than both Pr 2iTe (di- iso-propyltelluride) and Me 2Cd. The possible role of Hg in the growth of CdTe is also discussed. The chemistry of allylTePr i is well suited for use as an efficient precursor for epitaxial growth of tellurium containing semiconductors since there is very little formation of other organotellurium compounds on pyrolysis.

  1. Scale-up of the Reversible Addition-Fragmentation Chain Transfer (RAFT Polymerization Using Continuous Flow Processing

    Directory of Open Access Journals (Sweden)

    Nenad Micic

    2014-01-01

    Full Text Available A controlled radical polymerization process using the Reversible Addition-Fragmentation Chain Transfer (RAFT approach was scaled up by a factor of 100 from a small laboratory scale of 5 mL to a preparative scale of 500 mL, using batch and continuous flow processing. The batch polymerizations were carried out in a series of different glass vessels, using either magnetic or overhead stirring, and different modes of heating: Microwave irradiation or conductive heating in an oil bath. The continuous process was conducted in a prototype tubular flow reactor, consisting of 6 mm ID stainless steel tubing, fitted with static mixers. Both reactor types were tested for polymerizations of the acid functional monomers acrylic acid and 2-acrylamido-2-methylpropane-1-sulfonic acid in water at 80 °C with reaction times of 30 to 40 min. By monitoring the temperature during the exothermic polymerization process, it was observed that the type and size of reactor had a significant influence on the temperature profile of the reaction.

  2. Use of Lactococcus lactis subsp. cremoris NCDO 763 and α-ketoglutarate to improve the sensory quality of dry fermented sausages.

    Science.gov (United States)

    Herranz, B; Fernández, M; Hierro, E; Bruna, J M; Ordóñez, J A; de la Hoz, L

    2004-01-01

    The aim of the present work was to enhance the degradation of free amino acids in dry fermented sausages as precursors of volatile compounds responsible for the ripened flavour. For this purpose, Lactococcus lactis subsp. cremoris NCDO 763, its intracellular cell free extract (ICFE) and α-ketoglutarate were added to sausages. Papain was also used to increase the amount of free amino acids. When L. lactis was inoculated in sausages, an increase in the proteolytic phenomena was observed. The addition of α-ketoglutarate increased transamination phenomena in batches where it was added. The enhancement of these phenomena determined a noticeable rise in the content of glutamic acid (the main final product in transamination reactions) and a decrease, among other amino acids, of valine and leucine, with the formation of high amounts of their derivatives 2-methylpropanal and 3-methylbutanal. These aldehydes are responsible for the ripened flavour of dry fermented sausages. Sensory analysis showed an improvement of odour and flavour when L. lactis and α-ketoglutarate were combined. On the other hand, the intracellular cell free extract of L. lactis did not show any important activity in relation to amino acid breakdown even when used together with α-ketoglutarate and/or papain. PMID:22063943

  3. Direct nuclear magnetic resonance observation of odorant binding to mouse odorant receptor MOR244-3.

    Science.gov (United States)

    Burger, Jessica L; Jeerage, Kavita M; Bruno, Thomas J

    2016-06-01

    Mammals are able to perceive and differentiate a great number of structurally diverse odorants through the odorant's interaction with odorant receptors (ORs), proteins found within the cell membrane of olfactory sensory neurons. The natural gas industry has used human olfactory sensitivity to sulfur compounds (thiols, sulfides, etc.) to increase the safety of fuel gas transport, storage, and use through the odorization of this product. In the United States, mixtures of sulfur compounds are used, but the major constituent of odorant packages is 2-methylpropane-2-thiol, also known as tert-butyl mercaptan. It has been fundamentally challenging to understand olfaction and odorization due to the low affinity of odorous ligands to the ORs and the difficulty in expressing a sufficient number of OR proteins. Here, we directly observed the binding of tert-butyl mercaptan and another odiferous compound, cis-cyclooctene, to mouse OR MOR244-3 on living cells by saturation transfer difference (STD) nuclear magnetic resonance (NMR) spectroscopy. This effort lays the groundwork for resolving molecular mechanisms responsible for ligand binding and resulting signaling, which in turn will lead to a clearer understanding of odorant recognition and competition.

  4. Optimal Design for Reactivity Ratio Estimation: A Comparison of Techniques for AMPS/Acrylamide and AMPS/Acrylic Acid Copolymerizations

    Directory of Open Access Journals (Sweden)

    Alison J. Scott

    2015-11-01

    Full Text Available Water-soluble polymers of acrylamide (AAm and acrylic acid (AAc have significant potential in enhanced oil recovery, as well as in other specialty applications. To improve the shear strength of the polymer, a third comonomer, 2-acrylamido-2-methylpropane sulfonic acid (AMPS, can be added to the pre-polymerization mixture. Copolymerization kinetics of AAm/AAc are well studied, but little is known about the other comonomer pairs (AMPS/AAm and AMPS/AAc. Hence, reactivity ratios for AMPS/AAm and AMPS/AAc copolymerization must be established first. A key aspect in the estimation of reliable reactivity ratios is design of experiments, which minimizes the number of experiments and provides increased information content (resulting in more precise parameter estimates. However, design of experiments is hardly ever used during copolymerization parameter estimation schemes. In the current work, copolymerization experiments for both AMPS/AAm and AMPS/AAc are designed using two optimal techniques (Tidwell-Mortimer and the error-in-variables-model (EVM. From these optimally designed experiments, accurate reactivity ratio estimates are determined for AMPS/AAm (rAMPS = 0.18, rAAm = 0.85 and AMPS/AAc (rAMPS = 0.19, rAAc = 0.86.

  5. Proteinase-producing halophilic lactic acid bacteria isolated from fish sauce fermentation and their ability to produce volatile compounds.

    Science.gov (United States)

    Udomsil, Natteewan; Rodtong, Sureelak; Tanasupawat, Somboon; Yongsawatdigul, Jirawat

    2010-07-15

    Halophilic lactic acid bacteria were isolated from fish sauce mashes fermented at 1 to 12 months. Seven out of sixty-four isolates were selected according to their proteolytic activity and growth at 25% NaCl for characterization and investigation of volatile compound production. All selected isolates were Gram-positive cocci with pairs/tetrads and grew at 0-25% NaCl, pH 4.5-9.0. Results of 16S rRNA gene sequence analysis showed 99% homology to Tetragenococcus halophilus ATCC 33315. The restriction fragment length polymorphism (RFLP) patterns of all isolates were also similar to those of T. halophilus ATCC 33315. These isolates were, thus, identified as T. halophilus. All isolates hydrolyzed fish protein in the medium containing 25% NaCl. Intracellular aminopeptidase of 7 isolates exhibited the highest activity of 2.85-3.67 U/ml toward Ala-p-nitroanilide (Ala-pNA). T.halophilus strains MS33 and M11 showed the highest alanyl aminopeptidase activity (Phalophilus MS33 and MRC5-5-2 were 1-propanol, 2-methylpropanal, and benzaldehyde, corresponding to major volatile compounds in fish sauce. T.halophilus appeared to play an important role in volatile compound formation during fish sauce fermentation. PMID:20541276

  6. Use of Tetragenococcus halophilus as a starter culture for flavor improvement in fish sauce fermentation.

    Science.gov (United States)

    Udomsil, Natteewan; Rodtong, Sureelak; Choi, Yeung Joon; Hua, Yanglin; Yongsawatdigul, Jirawat

    2011-08-10

    The potential of Tetragenococcus halophilus as a starter culture for flavor improvement in fish sauce fermentation was elucidated. Four strains of T. halophilus isolated from fish sauce mashes were inoculated to anchovy mixed with 25% NaCl with an approximate cell count of 10(6) CFU/mL. The α-amino content of 6-month-old fish sauce samples inoculated with T. halophilus was 780-784 mM. The addition of T. halophilus MRC10-1-3 and T. halophilus MCD10-5-10 resulted in a reduction of histamine (P halophilus showed high contents of total amino acids with predominantly high glutamic acid. Major volatile compounds in fish sauce were 2-methylpropanal, 2-methylbutanal, 3-methylbutanal, and benzaldehyde. T. halophilus-inoculated fish sauce samples demonstrated the ability to reduce dimethyl disulfide, a compound contributing to a fecal note. The use of T. halophilus for fish sauce fermentation improves amino acid profiles and volatile compounds as well as reduces biogenic amine content of a fish sauce product. PMID:21710980

  7. Development and characterization of a novel, antimicrobial, sterile hydrogel dressing for burn wounds: single-step production with gamma irradiation creates silver nanoparticles and radical polymerization.

    Science.gov (United States)

    Boonkaew, Benjawan; Barber, Philip M; Rengpipat, Sirirat; Supaphol, Pitt; Kempf, Margit; He, Jibao; John, Vijay T; Cuttle, Leila

    2014-10-01

    Patients with burn wounds are susceptible to wound infection and sepsis. This research introduces a novel burn wound dressing that contains silver nanoparticles (SNPs) to treat infection in a 2-acrylamido-2-methylpropane sulfonic acid sodium salt (AMPS-Na(+) ) hydrogel. Silver nitrate was dissolved in AMPS-Na(+) solution and then exposed to gamma irradiation to form SNP-infused hydrogels. The gamma irradiation results in a cross-linked polymeric network of sterile hydrogel dressing and a reduction of silver ions to form SNPs infused in the hydrogel in a one-step process. About 80% of the total silver was released from the hydrogels after 72 h immersion in simulated body fluid solution; therefore, they could be used on wounds for up to 3 days. All the hydrogels were found to be nontoxic to normal human dermal fibroblast cells. The silver-loaded hydrogels had good inhibitory action against Pseudomonas aeruginosa and methicillin-resistant Staphylococcus aureus. Results from a pilot study on a porcine burn model showed that the 5-mM silver hydrogel was efficient at preventing bacterial colonization of wounds, and the results were comparable to the commercially available silver dressings (Acticoat(TM) , PolyMem Silver(®) ). These results support its use as a potential burn wound dressing.

  8. Configuration control on the shape memory stiffness of molecularly imprinted polymer for specific uptake of creatinine

    Science.gov (United States)

    Ang, Qian Yee; Zolkeflay, Muhammad Helmi; Low, Siew Chun

    2016-04-01

    In this study, sol-gel processing was proposed to prepare a creatinine (Cre)-imprinted molecularly imprinted polymer (MIP). The intermolecular interaction constituted by the cross-linkers, i.e., 2-acrylamido-2-methylpropane-sulfonic acid (AMPS) and aluminium ion (Al3+), was studied and compared in order to form a confined matrix that promises the effectiveness of molecular imprinting. In view of the shape recognition, the hydrogen bonded Cre-AMPS did not demonstrate good recognition of Cre, with Cre binding found only at 5.70 ± 0.15 mg g-1 of MIP. Whilst, MIP cross-linked using Al3+ was able to attain an excellent Cre adsorption capacity of 19.48 ± 0.64 mg g-1 of MIP via the stronger ionic interaction of Cre-Al3+. Based on the Scatchard analysis, a higher Cre concentration in testing solution required greater driving force to resolve the binding resistance of Cre molecules, so as to have a precise Cre binding with shape factor. The molecular recognition ability of Cre-MIP in present work was shape-specific for Cre as compared to its structural analogue, 2-pyrrolidinone (2-pyr), by an ideal selectivity coefficient of 6.57 ± 0.10. In overall, this study has come up with a practical approach on the preparation of MIP for the detection of renal dysfunction by point-of-care Cre testing.

  9. Volatile compound profile of sous-vide cooked lamb loins at different temperature-time combinations.

    Science.gov (United States)

    Roldán, Mar; Ruiz, Jorge; Del Pulgar, José Sánchez; Pérez-Palacios, Trinidad; Antequera, Teresa

    2015-02-01

    Lamb loins were subjected to sous-vide cooking at different combinations of temperature (60 and 80°C) and time (6 and 24h) to assess the effect on the volatile compound profile. Major chemical families in cooked samples were aliphatic hydrocarbons and aldehydes. The volatile compound profile in sous-vide cooked lamb loin was affected by the cooking temperature and time. Volatile compounds arising from lipid oxidation presented a high abundance in samples cooked at low or moderate cooking conditions (60°C for 6 and 24h, 80°C for 6h), while a more intense time and temperature combination (80°C for 24h) resulted on a higher concentration of volatile compounds arising from Strecker degradations of amino acids, as 2-methylpropanal and 3-methylbutanal. Therefore, sous-vide cooking at moderately high temperatures for long times would result in the formation of a stronger meaty flavor and roast notes in lamb meat.

  10. Transferable force field for alcohols and polyalcohols.

    Science.gov (United States)

    Ferrando, Nicolas; Lachet, Véronique; Teuler, Jean-Marie; Boutin, Anne

    2009-04-30

    A new force field has been developed for alcohol and polyalcohol molecules. Based on the anisotropic united-atom force field AUA4 developed for hydrocarbons, it only introduces one new anisotropic united atom corresponding to the hydroxyl group OH. In the case of polyalcohols and complex molecules, the calculation of the intramolecular electrostatic energy is revisited. These interactions are calculated between charges belonging to the different local dipoles of the molecule, one dipole being defined as a group of consecutive charges globally neutral. This new method allows avoiding the use of empirical scaling parameters commonly introduced to calculate 1-4 electrostatic interactions. The transferability of the proposed potential is demonstrated through the simulation of a wide variety of alcohol families: primary alcohols (methanol, ethanol, propan-1-ol, hexan-1-ol, octan-1-ol), secondary alcohols (propan-2-ol), tertiary alcohols (2-methylpropan-2-ol), phenol, and diols (1,2-ethanediol, 1,3-propanediol, 1,5-pentanediol). Monte Carlo simulations carried out in the Gibbs ensemble lead to a good agreement between calculated and experimental data for the thermodynamic properties along the liquid/vapor saturation curve, for the critical point coordinates and for the liquid structure at room temperature. Additional simulations were performed on the methanol + n-butane system showing the capability of the proposed potential to reproduce the azeotropic behavior of such mixtures with a good agreement. PMID:19344171

  11. Sulfonated macro-RAFT agents for the surfactant-free synthesis of cerium oxide-based hybrid latexes.

    Science.gov (United States)

    Garnier, Jérôme; Warnant, Jérôme; Lacroix-Desmazes, Patrick; Dufils, Pierre-Emmanuel; Vinas, Jérôme; van Herk, Alex

    2013-10-01

    Three types of amphiphatic macro-RAFT agents were employed as compatibilizers to promote the polymerization reaction at the surface of nanoceria for the synthesis of CeO2-based hybrid latexes. Macro-RAFT copolymers and terpolymers were first synthesized employing various combinations of butyl acrylate as a hydrophobic monomer and acrylic acid (AA) and/or 2-acrylamido-2-methylpropane sulfonic acid (AMPS) as hydrophilic monomers. After characterizing the adsorption of these macro-RAFT agents at the cerium oxide surface by UV-visible spectrometry, emulsion copolymerization reactions of styrene and methyl acrylate were then carried out in the presence of the surface-modified nanoceria. Dynamic Light Scattering and cryo-Transmission Electron Microscopy were employed to confirm the hybrid structure of the final CeO2/polymer latexes, and proved that the presence of acrylic acid units in amphiphatic macro-RAFT agents enabled an efficient formation of hybrid structures, while the presence of AMPS units, when combined with AA units, resulted in a better distribution of cerium oxide nanoclusters between latex particles.

  12. Experimental and modeling study of the oxidation of n- and iso-butanal

    KAUST Repository

    Veloo, Peter S.

    2013-09-01

    Understanding the kinetics of large molecular weight aldehydes is essential in the context of both conventional and alternative fuels. For example, they are key intermediates formed during the low-temperature oxidation of hydrocarbons as well as during the high-temperature oxidation of oxygenated fuels such as alcohols. In this study, an experimental and kinetic modeling investigation of n-butanal (. n-butyraldehyde) and iso-butanal (. iso-butyraldehyde or 2-methylpropanal) oxidation kinetics was performed. Experiments were performed in a jet stirred reactor and in counterflow flames over a wide range of equivalence ratios, temperatures, and pressures. The jet stirred reactor was utilized to observe the evolution of stable intermediates and products for the oxidation of n- and iso-butanal at elevated pressures and low to intermediate temperatures. The counterflow configuration was utilized for the determination of laminar flame speeds. A detailed chemical kinetic interpretative model was developed and validated consisting of 244 species and 1198 reactions derived from a previous study of the oxidation of propanal (propionaldehyde). Extensive reaction pathway and sensitivity analysis was performed to provide detailed insight into the mechanisms governing low-, intermediate-, and high-temperature reactivity. The simulation results using the present model are in good agreement with the experimental laminar flame speeds and well within a factor of two of the speciation data obtained in the jet stirred reactor. © 2013 The Combustion Institute.

  13. Characterization of protein hydrolysis and odor-active compounds of fish sauce inoculated with Virgibacillus sp. SK37 under reduced salt content.

    Science.gov (United States)

    Lapsongphon, Nawaporn; Cadwallader, Keith R; Rodtong, Sureelak; Yongsawatdigul, Jirawat

    2013-07-10

    The effect of Virgibacillus sp. SK37, together with reduced salt content, on fish sauce quality, particularly free amino acids and odor-active compounds, was investigated. Virgibacillus sp. SK37 was inoculated with an approximate viable count of 5 log CFU/mL in samples with varied amounts of solar salt, for example, 10, 15, and 20% of total weight. Eighteen selected odorants were quantitated by stable isotope dilution assays (SIDA), and their odor activity values (OAVs) were calculated. Samples prepared using 10% salt underwent spoilage after 7 days of fermentation. The viable count of Virgibacillus sp. SK37 was found over 3 months in the samples containing 15 and 20% salt. However, acceleration of protein hydrolysis was not pronounced in inoculated samples at both 15 and 20% salt. Virgibacillus sp. SK37, together with salt contents reduced to 15-20%, appeared to increase the content of 2-methylpropanal, 2-methylbutanal, 3-methylbutanal, acetic acid, and 2-methylpropanoic acid. However, only aldehydes were found to have an effect on the overall aroma of fish sauce based on high OAVs, suggesting that the inoculation of samples with Virgibacillus sp. SK37 under reduced salt contents of 15-20% likely contributed to stronger malty or dark chocolate notes. PMID:23768048

  14. Identification of the degradation pathways of alkanolamines with TiO{sub 2} photocatalysis

    Energy Technology Data Exchange (ETDEWEB)

    Lu, Chung-Shin, E-mail: cslu6@ntcnc.edu.tw [Department of General Education, National Taichung Nursing College, Taichung 403, Taiwan (China); Chen, Chiing-Chang [Department of Science Application and Dissemination, National Taichung University, Taichung 403, Taiwan (China); Mai, Fu-Der [Department of Biochemistry, School of Medicine, Taipei Medical University, Taipei 110, Taiwan (China); Li, Hua-Kuang [Department of General Education, National Taichung Nursing College, Taichung 403, Taiwan (China)

    2009-06-15

    The present study deals with the photocatalytic degradation of the alkanolamine, 2-dimethylamino-2-methyl-1-propanol (DMAMP), in the presence of TiO{sub 2} particles and UV-A ({lambda} = 365 nm) radiation. The obtained results show complete oxidation of DMAMP after 20 h, and a little over 90% of DMAMP was mineralization after 64-h of treatment. The effects of the solution pH, catalyst loading, and anions on the photocatalytic degradation of DMAMP were investigated, as well as the reaction intermediates that were formed during treatment. To the best of our knowledge, this is the first time that reports the degradation pathways of DMAMP. A number of intermediates were identified by GC/MS techniques during the treatment of DMAMP, following three tentative degradation routes. The first one is based on the oxidation of the primary alcohol group leading to the formation of corresponding aldehyde and carboxylic acid. The second route is based on the rupture of the N-C bond to form 2-methylpropanal and acetone. The last degradation route is based on the cyclization of the {beta}-amino alcohol group to form the oxazolidine derivatives.

  15. Identification of the degradation pathways of alkanolamines with TiO2 photocatalysis

    International Nuclear Information System (INIS)

    The present study deals with the photocatalytic degradation of the alkanolamine, 2-dimethylamino-2-methyl-1-propanol (DMAMP), in the presence of TiO2 particles and UV-A (λ = 365 nm) radiation. The obtained results show complete oxidation of DMAMP after 20 h, and a little over 90% of DMAMP was mineralization after 64-h of treatment. The effects of the solution pH, catalyst loading, and anions on the photocatalytic degradation of DMAMP were investigated, as well as the reaction intermediates that were formed during treatment. To the best of our knowledge, this is the first time that reports the degradation pathways of DMAMP. A number of intermediates were identified by GC/MS techniques during the treatment of DMAMP, following three tentative degradation routes. The first one is based on the oxidation of the primary alcohol group leading to the formation of corresponding aldehyde and carboxylic acid. The second route is based on the rupture of the N-C bond to form 2-methylpropanal and acetone. The last degradation route is based on the cyclization of the β-amino alcohol group to form the oxazolidine derivatives.

  16. Volatile compound profile of sous-vide cooked lamb loins at different temperature-time combinations.

    Science.gov (United States)

    Roldán, Mar; Ruiz, Jorge; Del Pulgar, José Sánchez; Pérez-Palacios, Trinidad; Antequera, Teresa

    2015-02-01

    Lamb loins were subjected to sous-vide cooking at different combinations of temperature (60 and 80°C) and time (6 and 24h) to assess the effect on the volatile compound profile. Major chemical families in cooked samples were aliphatic hydrocarbons and aldehydes. The volatile compound profile in sous-vide cooked lamb loin was affected by the cooking temperature and time. Volatile compounds arising from lipid oxidation presented a high abundance in samples cooked at low or moderate cooking conditions (60°C for 6 and 24h, 80°C for 6h), while a more intense time and temperature combination (80°C for 24h) resulted on a higher concentration of volatile compounds arising from Strecker degradations of amino acids, as 2-methylpropanal and 3-methylbutanal. Therefore, sous-vide cooking at moderately high temperatures for long times would result in the formation of a stronger meaty flavor and roast notes in lamb meat. PMID:25306511

  17. Intermolecular Hydrogen Transfer in Isobutane Hydrate

    Directory of Open Access Journals (Sweden)

    Takeshi Sugahara

    2012-05-01

    Full Text Available Electron spin resonance (ESR spectra of butyl radicals induced with γ-ray irradiation in the simple isobutane (2-methylpropane hydrate (prepared with deuterated water were investigated. Isothermal annealing results of the γ-ray-irradiated isobutane hydrate reveal that the isobutyl radical in a large cage withdraws a hydrogen atom from the isobutane molecule through shared hexagonal-faces of adjacent large cages. During this “hydrogen picking” process, the isobutyl radical is apparently transformed into a tert-butyl radical, while the sum of isobutyl and tert-butyl radicals remains constant. The apparent transformation from isobutyl to tert-butyl radicals is an irreversible first-order reaction and the activation energy was estimated to be 35 ± 3 kJ/mol, which was in agreement with the activation energy (39 ± 5 kJ/mol of hydrogen picking in the γ-ray-irradiated propane hydrate with deuterated water.

  18. Dispersion of iron oxide particles in industrial waters. The influence of polymer structure, ionic charge, and molecular weight

    Energy Technology Data Exchange (ETDEWEB)

    Amjad, Z. [Goodrich (B.F.) Co., Brecksville, OH (United States)

    1999-01-01

    This paper deals with studies on the influence of polymeric and non-polymeric materials on the dispersion of iron oxide particles in aqueous system. The aim of the work was to evaluate the performance of a variety of additives as iron oxide dispersants. The polymers investigated include homopolymers of acrylamide, vinylpyrrolidone, actylic acid, maleic acid, 2-acrylamido-2-methylpropane sulfonic acid, and acrylic acid based copolymers containing a variety of functional groups. It has been found that the addition of low levels of copolymers to the iron oxide suspension has a marked effect in dispersing iron oxide particles. The dispersancy data of several polymers indicate that the performance of the polymer depends upon the functional group, molecular weight, composition, and the ionic charge of the polymer. The results on non-polymeric materials such as polyphosphates, phosphonates, and surfactants show that these additives, compared to copolymers are ineffective as iron oxide dispersants. (orig.) [Deutsch] In dieser Arbeit wird der Einfluss von polymeren und nichtpolymeren Stoffen auf die Dispergierung von Eisenoxidpartikeln in waessrigen Systemen untersucht. Ziel dieser Arbeit war es, die Wirkung verschiedener Additive als Eisenoxiddispergatoren zu bewerten. Die untersuchten Polymere waren homopolymeres Acrylamid, Vinylpyrrolidon, Acrylsaeure, Maleinsaeure, 2-Acrylamido-2-Methylpropansulfonsaeure und Copolymere auf Acrylsaeurebasis mit verschiedenen fuktionellen Gruppen. Die Zugabe von geringen Mengen Copolymeren zur Eisenoxidsuspension hat einen deutlichen Einfluss auf die Dispergierung dieser Partikel. Die Daten zum Dispergierverhalten einiger Polymere zeigen, dass die Wirkung eines Polymers von der fuktionellen Gruppe, dem Molgewicht, der Zusammensetzung und der Ionenladung des Polymers abhaengt. Ergebnisse, die mit nichtpolymeren Substanzen wie Polyphosphaten, Phosphonaten und Tensiden erhalten wurden, zeigen, dass sich diese Additive nicht so gut als

  19. Synthesis of Discodermolide Subunits by S(E)2' Addition of Nonracemic Allenylstannanes to Aldehydes.

    Science.gov (United States)

    Marshall, James A.; Lu, Zhi-Hui; Johns, Brian A.

    1998-02-01

    Three subunits, 15, 29, and 34, of the immunosuppressant discodermolide were prepared starting from (S)-3-[(tert-butyldimethylsilyl)oxy]-2-methylpropanal ((S)-1) and the enantioenriched allenylstannanes (P)-2a, (P)-2b, and (P)-31. The route to 15 involved BF(3)-promoted addition of stannane (P)-2a to aldehyde (S)-1 which afforded the syn,syn-homopropargylic alcohol adduct 3 in 97% yield. The derived p-methoxybenzylidene acetal 5 was treated with Red-Al to effect cleavage of the pivalate and reduction of the double bond leading to the (E)-allylic alcohol 6. Sharpless epoxidation and subsequent addition of Me(2)CuCNLi(2) yielded the syn,syn,syn,anti stereopentad, diol 8. Protection of the secondary alcohol and oxidation of the primary gave aldehyde 12, which was treated with the alpha-bromo allylsilane 13 and CrCl(2), followed by NaH to effect elimination to the diene 15. A similar sequence was employed to prepare aldehyde 29. In this case aldehyde (S)-1 was converted to the anti,syn-homopropargylic alcohol 20 by treatment with the allenyl indium reagent formed in situ from allenylstannane (P)-2b and InBr(3). Epoxy alcohol 24, prepared from alcohol 20 by the above-described sequence, was reduced with Red-Al to afford diol 25. Protection of the secondary alcohol and oxidation of the primary completed the synthesis of 29. The anti,syn-homopropargylic alcohol 32 was obtained through addition of the allenic indium reagent, from allenylstannane (P)-31, to aldehyde (S)-1. Protection of the derived diol 33 as the p-methoxybenzylidene acetal afforded the third subunit, acetylene 34. Addition of the lithio derivative of 34 to aldehyde 29 gave alcohol 35 with the carbinyl stereochemistry needed for C7 of discodermolide as the major product.

  20. Hydrolysis and Photolysis of Herbicide Clomazone in Aqueous Solutions and Natural Water Under Abiotic Conditions

    Institute of Scientific and Technical Information of China (English)

    CAO Jia; DIAO Xiao-ping; HU Ji-ye

    2013-01-01

    The hydrolysis and photolysis of clomazone in aqueous solutions and natural water were assessed under natural and controlled conditions. Kinetics of hydrolysis and photolysis of clomazone were determined by HPLC-DAD. Photoproducts were identiifed by HPLC-MS. No noticeable hydrolysis occurred in aqueous buffer solutions ((25±2)°C, pH (4.5±0.1), pH (7.4±0.1), pH (9.0±0.1);(50±2)°C, pH (4.5±0.1), pH (7.4±0.1)) or in natural water up to 90 d. At pH (9.0±0.1) and (50±2)°C the half-life of clomazone was 50.2 d. Clomazone photodecomposition rate in aqueous solutions under UV radiation and natural sunlight followed ifrst-order kinetics. Degradation rates were faster under UV light (half-life of 51-59 min) compared to sunlight (half-life of 87-136 d). Under UV light, four major photoproducts were detected and tentatively identiifed according to HPLC-MS spectral information such as 2-chlorobenzamide, N-hydroxy-(2-benzyl)-2-methylpropan-amide, 2-[2-phenol]-4,4-dimethyl-3-isoxazolidinone and 2-[(4,6-dihydroxyl-2-chlorine phenol)]-4,4-dimethyl-3-isoxazolidinone. These results suggested that clomazone photodegradation proceeds via several reaction pathways:1) dehalogenation;2) substitution of chlorine group by hydroxyl;3) cleavage of the side chain. Photosensitizers, such as H2O2 and ribolfavin, could enhance photolysis of clomazone in natural sunlight. In summary, we found that photoreaction is an important dissipation pathway of clomazone in natural water systems.

  1. Oxytetracycline recovery from aqueous media using computationally designed molecularly imprinted polymers.

    Science.gov (United States)

    Rodríguez-Dorado, Rosalía; Carro, Antonia M; Chianella, Iva; Karim, Kal; Concheiro, Angel; Lorenzo, Rosa A; Piletsky, Sergey; Alvarez-Lorenzo, Carmen

    2016-09-01

    Polymers for recovery/removal of the antimicrobial agent oxytetracycline (OTC) from aqueous media were developed with use of computational design and molecular imprinting. 2-Hydroxyethyl methacrylate, 2-acrylamide-2-methylpropane sulfonic acid (AMPS), and mixtures of the two were chosen according to their predicted affinity for OTC and evaluated as functional monomers in molecularly imprinted polymers and nonimprinted polymers. Two levels of AMPS were tested. After bulk polymerization, the polymers were crushed into particles (200-1000 μm). Pressurized liquid extraction was implemented for template removal with a low amount of methanol (less than 20 mL in each extraction) and a few extractions (12-18 for each polymer) in a short period (20 min per extraction). Particle size distribution, microporous structure, and capacity to rebind OTC from aqueous media were evaluated. Adsorption isotherms obtained from OTC solutions (30-110 mg L(-1)) revealed that the polymers prepared with AMPS had the highest affinity for OTC. The uptake capacity depended on the ionic strength as follows: purified water > saline solution (0.9 % NaCl) > seawater (3.5 % NaCl). Polymer particles containing AMPS as a functional monomer showed a remarkable ability to clean water contaminated with OTC. The usefulness of the stationary phase developed for molecularly imprinted solid-phase extraction was also demonstrated. Graphical Abstract Selection of functional monomers by molecular modeling renders polymer networks suitable for removal of pollutants from contaminated aqueous environments, under either dynamic or static conditions. PMID:27488280

  2. Singlet molecular oxygen generated in dark biological process.

    Science.gov (United States)

    Di Mascio, Paolo; Medeiros, Marisa H G

    2014-10-01

    Ultraweak chemiluminescence arising from biomolecules oxidation has been attributed to the radiative deactivation of singlet molecular oxygen [(1)O2] and electronically excited triplet carbonyl products involving dioxetane intermediates. As examples, we will discuss the generation of (1)O2 from lipid hydroperoxides, which involves a cyclic mechanism from a linear tetraoxide intermediate. The generation of (1)O2 in aqueous solution via energy transfer from the excited triplet acetone arising from the thermodecomposition of dioxetane a chemical source, and horseradish peroxidase-catalyzed oxidation of 2-methylpropanal, as an enzymatic source, will also be discussed. The approach used to unequivocally demonstrate the generation of (1)O2 in these reactions is the use of (18)O-labeled hydroperoxide / triplet dioxygen ((18)[(3)O2]), the detection of labeled compounds by HPLC coupled to tandem mass spectrometry (HPLC-MS/MS) and the direct spectroscopic detection and characterization of (1)O2 light emission. Characteristic light emission at 1,270nm, corresponding to the singlet delta state monomolecular decay was observed. Using(18)[(3)O2], we observed the formation of (18)O-labeled (1)O2 ((18)[(1)O2]) by the chemical trapping of (18)[(1)O2]with the anthracene-9,10-diyldiethane-2,1-diyl disulfate disodium salt (EAS) and detected the corresponding (18)O-labeled EAS endoperoxide usingHPLC-MS/MS. The combined use of the thermolysis of a water-soluble naphthalene endoperoxide as a generator of (18)O labeled (1)O2 and the sensitivity of HPLC-MS/MS allowed the study of (1)O2reactivity toward biomolecules. Photoemission properties and chemical trapping clearly demonstrate that the production of hydroperoxide and excited carbonyls generates (18)[(1)O2], and points to the involvement of (1)O2 in physiological and pathophysiological mechanism. Supported by FAPESP (2012/12663-1), CAPES, INCT Redoxoma (FAPESP/CNPq/CAPES; 573530/2008-4), NAP Redoxoma (PRPUSP; 2011.1.9352.1.8), CEPID

  3. Comparison of different real time VOC measurement techniques in a ponderosa pine forest

    Directory of Open Access Journals (Sweden)

    L. Kaser

    2012-10-01

    Full Text Available Volatile organic compound (VOC mixing ratios measured by five independent instruments are compared at a forested site dominated by ponderosa pine (Pinus Ponderosa during the BEACHON-ROCS field study in summer 2010. The instruments included a Proton Transfer Reaction Time of Flight Mass Spectrometer (PTR-TOF-MS, a Proton Transfer Reaction Quadrupole Mass Spectrometer (PTR-MS, a Fast Online Gas-Chromatograph coupled to a Mass Spectrometer (GC/MS; TOGA, a Thermal Dissociation Chemical Ionization Mass Spectrometer (PAN-CIMS and a Fiber Laser-Induced Fluorescence Instrument (FILIF. The species discussed in this comparison include the most important biogenic VOCs and a selected suite of oxygenated VOCs that are thought to dominate the VOC reactivity at this particular site as well as typical anthropogenic VOCs that showed low mixing ratios at this site. Good agreement was observed for methanol, the sum of the oxygenated hemiterpene 2-methyl-3-buten-2-ol (MBO and the hemiterpene isoprene, acetaldehyde, the sum of acetone and propanal, benzene and the sum of methyl ethyl ketone (MEK and butanal. Measurements of the above VOCs conducted by different instruments agree within 20%. The ability to differentiate the presence of toluene and cymene by PTR-TOF-MS is tested based on a comparison with GC-MS measurements, suggesting a study-average relative contribution of 74% for toluene and 26% for cymene. Similarly, 2-hydroxy-2-methylpropanal (HMPR is found to interfere with the sum of methyl vinyl ketone and methacrolein (MVK+MAC using PTR-(TOF-MS at this site. A study-average relative contribution of 85% for MVK+MAC and 15% for HMPR was determined. The sum of monoterpenes measured by PTR-MS and PTR-TOF-MS was generally 20–25% higher than the sum of speciated monoterpenes measured by TOGA, which included α-pinene, β-pinene, camphene, carene, myrcene, limonene, cineole as well as other terpenes. However, this difference is consistent throughout the

  4. Comparison of different real time VOC measurement techniques in a ponderosa pine forest

    Directory of Open Access Journals (Sweden)

    L. Kaser

    2013-03-01

    Full Text Available Volatile organic compound (VOC mixing ratios measured by five independent instruments are compared at a forested site dominated by ponderosa pine (Pinus Ponderosa during the BEACHON-ROCS field study in summer 2010. The instruments included a Proton Transfer Reaction Time of Flight Mass Spectrometer (PTR-TOF-MS, a Proton Transfer Reaction Quadrupole Mass Spectrometer (PTR-MS, a Fast Online Gas-Chromatograph coupled to a Mass Spectrometer (GC/MS; TOGA, a Thermal Dissociation Chemical Ionization Mass Spectrometer (PAN-CIMS and a Fiber Laser-Induced Fluorescence Instrument (FILIF. The species discussed in this comparison include the most important biogenic VOCs and a selected suite of oxygenated VOCs that are thought to dominate the VOC reactivity at this particular site as well as typical anthropogenic VOCs that showed low mixing ratios at this site. Good agreement was observed for methanol, the sum of the oxygenated hemiterpene 2-methyl-3-buten-2-ol (MBO and the hemiterpene isoprene, acetaldehyde, the sum of acetone and propanal, benzene and the sum of methyl ethyl ketone (MEK and butanal. Measurements of the above VOCs conducted by different instruments agree within 20%. The ability to differentiate the presence of toluene and cymene by PTR-TOF-MS is tested based on a comparison with GC-MS measurements, suggesting a study-average relative contribution of 74% for toluene and 26% for cymene. Similarly, 2-hydroxy-2-methylpropanal (HMPR is found to interfere with the sum of methyl vinyl ketone and methacrolein (MVK + MAC using PTR-(TOF-MS at this site. A study-average relative contribution of 85% for MVK + MAC and 15% for HMPR was determined. The sum of monoterpenes measured by PTR-MS and PTR-TOF-MS was generally 20–25% higher than the sum of speciated monoterpenes measured by TOGA, which included α-pinene, β-pinene, camphene, carene, myrcene, limonene, cineole as well as other terpenes. However, this difference is consistent throughout the study

  5. Indigenous Georgian Wine-Associated Yeasts and Grape Cultivars to Edit the Wine Quality in a Precision Oenology Perspective.

    Science.gov (United States)

    Vigentini, Ileana; Maghradze, David; Petrozziello, Maurizio; Bonello, Federica; Mezzapelle, Vito; Valdetara, Federica; Failla, Osvaldo; Foschino, Roberto

    2016-01-01

    In Georgia, one of the most ancient vine-growing environment, the homemade production of wine is still very popular in every rural family and spontaneous fermentation of must, without addition of chemical preservatives, is the norm. The present work investigated the yeast biodiversity in five Georgian areas (Guria, Imereti, Kakheti, Kartli, Ratcha-Lechkhumi) sampling grapes and wines from 22 different native cultivars, in 26 vineyards and 19 family cellars. One hundred and eighty-two isolates were ascribed to 15 different species by PCR-ITS and RFLP, and partial sequencing of D1/D2 domain 26S rDNA gene. Metschnikowia pulcherrima (F' = 0.56, I' = 0.32), Hanseniaspora guilliermondii (F' = 0.49, I' = 0.27), and Cryptococcus flavescens (F' = 0.31, I' = 0.11) were the dominant yeasts found on grapes, whereas Saccharomyces cerevisiae showed the highest prevalence into wine samples. Seventy four isolates with fermentative potential were screened for oenological traits such as ethanol production, resistance to SO2, and acetic acid, glycerol and H2S production. Three yeast strains (Kluyveromyces marxianus UMY207, S. cerevisiae UMY255, Torulaspora delbrueckii UMY196) were selected and separately inoculated in vinifications experiments at a Georgian cellar. Musts were prepared from healthy grapes of local varieties, Goruli Mtsvane (white berry cultivar) and Saperavi (black berry cultivar). Physical (°Brix) and microbial analyses (plate counts) were performed to monitor the fermentative process. The isolation of indigenous S. cerevisiae yeasts beyond the inoculated strains indicated that a co-presence occurred during the vinification tests. Results from quantitative GC-FID analysis of volatile compounds revealed that the highest amount of fermentation flavors, such as 4-ethoxy-4-oxobutanoic acid (monoethyl succinate), 2-methylpropan-1-ol, ethyl 2-hydroxypropanoate, and 2-phenylethanol, were significantly more produced in fermentation conducted in Saperavi variety inoculated

  6. Computer aided screening and evaluation of herbal therapeutics against MRSA infections.

    Science.gov (United States)

    Skariyachan, Sinosh; Krishnan, Rao Shruti; Siddapa, Snehapriya Bangalore; Salian, Chithra; Bora, Prerana; Sebastian, Denoj

    2011-01-01

    Methicillin resistant Staphylococcus aureus (MRSA), a pathogenic bacterium that causes life threatening outbreaks such as community-onset and nosocomial infections has emerged as 'superbug'. The organism developed resistance to all classes of antibiotics including the best known Vancomycin (VRSA). Hence, there is a need to develop new therapeutic agents. This study mainly evaluates the potential use of botanicals against MRSA infections. Computer aided design is an initial platform to screen novel inhibitors and the data finds applications in drug development. The drug-likeness and efficiency of various herbal compounds were screened by ADMET and docking studies. The virulent factor of most of the MRSA associated infections are Penicillin Binding Protein 2A (PBP2A) and Panton-Valentine Leukocidin (PVL). Hence, native structures of these proteins (PDB: 1VQQ and 1T5R) were used as the drug targets. The docking studies revealed that the active component of Aloe vera, β-sitosterol (3S, 8S, 9S, 10R, 13R, 14S, 17R) -17- [(2R, 5R)-5-ethyl-6-methylheptan-2-yl] -10, 13-dimethyl 2, 3, 4, 7, 8, 9, 11, 12, 14, 15, 16, 17- dodecahydro-1H-cyclopenta [a] phenanthren-3-ol) showed best binding energies of -7.40 kcal/mol and -6.34 kcal/mol for PBP2A and PVL toxin, respectively. Similarly, Meliantriol (1S-1-[ (2R, 3R, 5R)-5-hydroxy-3-[(3S, 5R, 9R, 10R, 13S, 14S, 17S)-3-hydroxy 4, 4, 10, 13, 14-pentamethyl-2, 3, 5, 6, 9, 11, 12, 15, 16, 17-decahydro-1H-cyclopenta[a] phenanthren-17-yl] oxolan-2-yl] -2- methylpropane-1, 2 diol), active compound in Azadirachta indica (Neem) showed the binding energies of -6.02 kcal/mol for PBP2A and -8.94 for PVL toxin. Similar studies were conducted with selected herbal compound based on pharmacokinetic properties. All in silico data tested in vitro concluded that herbal extracts of Aloe-vera, Neem, Guava (Psidium guajava), Pomegranate (Punica granatum) and tea (Camellia sinensis) can be used as therapeutics against MRSA infections. PMID:22125390

  7. Thermochemical Properties Enthalpy, Entropy, and Heat Capacity of C1-C4 Fluorinated Hydrocarbons: Fluorocarbon Group Additivity.

    Science.gov (United States)

    Wang, Heng; Castillo, Álvaro; Bozzelli, Joseph W

    2015-07-23

    Enthalpies of formation for 14 C2–C4 fluorinated hydrocarbons were calculated with nine popular ab initio and density functional theory methods: B3LYP, CBS-QB3, CBS-APNO, M06, M06-2X, ωB97X, G4, G4(MP2)-6X, and W1U via several series of isodesmic reactions. The recommended ideal gas phase ΔHf298° (kcal mol(–1)) values calculated in this study are the following: −65.4 for CH3CH2F; −70.2 for CH3CH2CH2F; −75.3 for CH3CHFCH3; −75.2 for CH3CH2CH2CH2F; −80.3 for CH3CHFCH2CH3; −108.1 for CH2F2; −120.9 for CH3CHF2; −125.8 for CH3CH2CHF2; −133.3 for CH3CF2CH3; −166.7 for CHF3; −180.5 for CH3CF3; −185.5 for CH3CH2CF3; −223.2 for CF4; and −85.8 for (CH3)3CF. Entropies (S298° in cal mol(–1) K(–1)) were estimated using B3LYP/6-31+G(d,p) computed frequencies and geometries. Rotational barriers were determined and hindered internal rotational contributions for S298°, and Cp(T) were calculated using the rigid rotor harmonic oscillator approximation, with direct integration over energy levels of the intramolecular rotation potential energy curve. Thermochemical properties for the fluorinated carbon groups C/C/F/H2, C/C2/F/H, C/C/F2/H, C/C2/F2, and C/C/F3 were derived from the above target fluorocarbons. Previously published enthalpies and groups for 1,2-difluoroethane, 1,1,2-trifluoroethane, 1,1,2,2-tetrafluoroethane, 1,1,1,2-tetrafluoroethane, 1,1,1,2,2-pentafluoroethane, 2-fluoro-2-methylpropane that were previously determined via work reaction schemes are revised using updated reference species values. Standard deviations are compared for the calculation methods.

  8. Indigenous Georgian wine-associated yeasts and grape cultivars to edit the wine quality in a precision oenology perspective

    Directory of Open Access Journals (Sweden)

    Ileana eVigentini

    2016-03-01

    Full Text Available In Georgia, one of the most ancient vine-growing environment, the homemade production of wine is still very popular in every rural family and spontaneous fermentation of must, without addition of chemical preservatives, is the norm. The present work investigated the yeast biodiversity in five Georgian areas (Guria, Imereti, Kakheti, Kartli, Ratcha-Lechkhumi sampling grapes and wines from 22 different native cultivars, in 26 vineyards and 19 family cellars. One hundred and eighty-two isolates were ascribed to 15 different species by PCR-ITS and RFLP, and partial sequencing of D1/D2 domain 26S rDNA gene. Metschnikowia pulcherrima (F’ = 0.56, I’ = 0.32, Hanseniaspora gulliermondii (F’ = 0.49, I’ = 0.27 and Cryptococcus flavescens (F’ = 0.31, I’ = 0.11 were the dominant yeasts found on grapes, whereas Saccharomyces cerevisiae showed the highest prevalence into wine samples. Seventy four isolates with fermentative potential were screened for oenological traits such as ethanol production, resistance to SO2, and acetic acid, glycerol and H2S production. Three yeast strains (Kluyveromyces marxianus UMY207, S. cerevisiae UMY255, Torulaspora delbrueckii UMY196 were selected and separately inoculated in vinifications experiments at a Georgian cellar. Musts were prepared from healthy grapes of local varieties, Goruli Mtsvane (white berry cultivar and Saperavi (black berry cultivar. Physical (°Brix and microbial analyses (plate counts were performed to monitor the fermentative process. The isolation of indigenous S. cerevisiae yeasts beyond the inoculated strains indicated that a co-presence occurred during the vinification tests. Results from quantitative GC-FID analysis of volatile compounds revealed that the highest amount of fermentation flavours, such as 4-ethoxy-4-oxobutanoic acid (monoethyl succinate, 2-methylpropan-1-ol, ethyl 2-hydroxypropanoate and 2-phenylethanol, were significantly more produced in fermentation conducted in Saperavi

  9. Biosynthesis of the cyanogenic glucosides linamarin and lotaustralin in cassava: isolation, biochemical characterization, and expression pattern of CYP71E7, the oxime-metabolizing cytochrome P450 enzyme.

    Science.gov (United States)

    Jørgensen, Kirsten; Morant, Anne Vinther; Morant, Marc; Jensen, Niels Bjerg; Olsen, Carl Erik; Kannangara, Rubini; Motawia, Mohammed Saddik; Møller, Birger Lindberg; Bak, Søren

    2011-01-01

    Cassava (Manihot esculenta) is a eudicotyledonous plant that produces the valine- and isoleucine-derived cyanogenic glucosides linamarin and lotaustralin with the corresponding oximes and cyanohydrins as key intermediates. CYP79 enzymes catalyzing amino acid-to-oxime conversion in cyanogenic glucoside biosynthesis are known from several plants including cassava. The enzyme system converting oxime into cyanohydrin has previously only been identified in the monocotyledonous plant great millet (Sorghum bicolor). Using this great millet CYP71E1 sequence as a query in a Basic Local Alignment Search Tool-p search, a putative functional homolog that exhibited an approximately 50% amino acid sequence identity was found in cassava. The corresponding full-length cDNA clone was obtained from a plasmid library prepared from cassava shoot tips and was assigned CYP71E7. Heterologous expression of CYP71E7 in yeast afforded microsomes converting 2-methylpropanal oxime (valine-derived oxime) and 2-methylbutanal oxime (isoleucine-derived oxime) to the corresponding cyanohydrins, which dissociate into acetone and 2-butanone, respectively, and hydrogen cyanide. The volatile ketones were detected as 2.4-dinitrophenylhydrazone derivatives by liquid chromatography-mass spectrometry. A K(S) of approximately 0.9 μm was determined for 2-methylbutanal oxime based on substrate-binding spectra. CYP71E7 exhibits low specificity for the side chain of the substrate and catalyzes the conversion of aliphatic and aromatic oximes with turnovers of approximately 21, 17, 8, and 1 min(-1) for the oximes derived from valine, isoleucine, tyrosine, and phenylalanine, respectively. A second paralog of CYP71E7 was identified by database searches and showed approximately 90% amino acid sequence identity. In tube in situ polymerase chain reaction showed that in nearly unfolded leaves, the CYP71E7 paralogs are preferentially expressed in specific cells in the endodermis and in most cells in the first cortex

  10. Indigenous Georgian Wine-Associated Yeasts and Grape Cultivars to Edit the Wine Quality in a Precision Oenology Perspective

    Science.gov (United States)

    Vigentini, Ileana; Maghradze, David; Petrozziello, Maurizio; Bonello, Federica; Mezzapelle, Vito; Valdetara, Federica; Failla, Osvaldo; Foschino, Roberto

    2016-01-01

    In Georgia, one of the most ancient vine-growing environment, the homemade production of wine is still very popular in every rural family and spontaneous fermentation of must, without addition of chemical preservatives, is the norm. The present work investigated the yeast biodiversity in five Georgian areas (Guria, Imereti, Kakheti, Kartli, Ratcha-Lechkhumi) sampling grapes and wines from 22 different native cultivars, in 26 vineyards and 19 family cellars. One hundred and eighty-two isolates were ascribed to 15 different species by PCR-ITS and RFLP, and partial sequencing of D1/D2 domain 26S rDNA gene. Metschnikowia pulcherrima (F’ = 0.56, I’ = 0.32), Hanseniaspora guilliermondii (F’ = 0.49, I’ = 0.27), and Cryptococcus flavescens (F’ = 0.31, I’ = 0.11) were the dominant yeasts found on grapes, whereas Saccharomyces cerevisiae showed the highest prevalence into wine samples. Seventy four isolates with fermentative potential were screened for oenological traits such as ethanol production, resistance to SO2, and acetic acid, glycerol and H2S production. Three yeast strains (Kluyveromyces marxianus UMY207, S. cerevisiae UMY255, Torulaspora delbrueckii UMY196) were selected and separately inoculated in vinifications experiments at a Georgian cellar. Musts were prepared from healthy grapes of local varieties, Goruli Mtsvane (white berry cultivar) and Saperavi (black berry cultivar). Physical (°Brix) and microbial analyses (plate counts) were performed to monitor the fermentative process. The isolation of indigenous S. cerevisiae yeasts beyond the inoculated strains indicated that a co-presence occurred during the vinification tests. Results from quantitative GC-FID analysis of volatile compounds revealed that the highest amount of fermentation flavors, such as 4-ethoxy-4-oxobutanoic acid (monoethyl succinate), 2-methylpropan-1-ol, ethyl 2-hydroxypropanoate, and 2-phenylethanol, were significantly more produced in fermentation conducted in Saperavi variety

  11. pH dependent photophysical studies of new europium and terbium complexes of tripodal ligand: Experimental and semiempirical approach

    International Nuclear Information System (INIS)

    The photophysical properties of adduct of a novel nonadentate tripodal ligand, 5,5′-(2-(((8-hydroxyquinolin-5-yl)methylamino)methyl)-2-methylpropane-1, 3-diyl)bis(azanediyl)bis(methylene diquinolin-8-ol, (TAME5OX), with Eu3+ and Tb3+ metal ions have been probed for photonics applications. The absorption spectroscopy of these complexes show remarkable spectral changes due to characteristic lanthanide transitions, which support the use of TAME5OX as a sensitive optical pH based sensor to detect Ln3+ metal ions in biological systems. In addition, these complexes have also been shown to exhibit strong green fluorescence allowing simultaneous sensing within the visible region under physiological pH in competitive medium for both Eu3+ and Tb3+ ions. The intense fluorescence from these compounds were revealed to intermittently get quenched under acidic as well as basic conditions due to the photoinduced intramolecular electron transfer from excited 8-hydroxyquinoline (8-HQ) moiety to metal ion, just an opposite process. This renders these compounds the OFF–ON–OFF type of pH-dependent fluorescent sensor. The thermodynamic stability and aqueous coordination chemistry of the chelator with the said lanthanide ions have also been probed by potentiometric, UV–visible and fluorescence spectrophotometric method. TAME5OX has been found to form two protonated complexes [Ln(H5L)]5+ and [Ln(H4L)]4+ below pH 2.5 with both metal ions, which consecutively deprotonates through one proton process with rise of pH. The formation constants (log β11n) of neutral complexes have been determined to be 33.51 and 32.16 with pLn (pLn=−log[Ln3+]) values of 16.14 and 19.48 for Eu3+ and Tb3+ ions, respectively, calculated at pH 7.4, indicating TAME5OX is a good lanthanide synthetic chelator. The emission lifetimes of the Eu3+ and Tb3+ complexes recorded in D2O and H2O suggest the presence of water molecules in the first coordination sphere of the metal ions. NMR titrations were carried out

  12. pH dependent photophysical studies of new europium and terbium complexes of tripodal ligand: Experimental and semiempirical approach

    Energy Technology Data Exchange (ETDEWEB)

    Akbar, Rifat [Department of Chemistry, Sant Longowal Institute of Engineering & Technology, Longowal, Punjab 148106 (India); Baral, Minati [Department of Chemistry, National Institute of Technology Kurukshetra, Haryana 136119 (India); Kanungo, B K, E-mail: b.kanungo@gmail.com [Department of Chemistry, Sant Longowal Institute of Engineering & Technology, Longowal, Punjab 148106 (India)

    2015-11-15

    The photophysical properties of adduct of a novel nonadentate tripodal ligand, 5,5′-(2-(((8-hydroxyquinolin-5-yl)methylamino)methyl)-2-methylpropane-1, 3-diyl)bis(azanediyl)bis(methylene diquinolin-8-ol, (TAME5OX), with Eu{sup 3+} and Tb{sup 3+} metal ions have been probed for photonics applications. The absorption spectroscopy of these complexes show remarkable spectral changes due to characteristic lanthanide transitions, which support the use of TAME5OX as a sensitive optical pH based sensor to detect Ln{sup 3+} metal ions in biological systems. In addition, these complexes have also been shown to exhibit strong green fluorescence allowing simultaneous sensing within the visible region under physiological pH in competitive medium for both Eu{sup 3+} and Tb{sup 3+} ions. The intense fluorescence from these compounds were revealed to intermittently get quenched under acidic as well as basic conditions due to the photoinduced intramolecular electron transfer from excited 8-hydroxyquinoline (8-HQ) moiety to metal ion, just an opposite process. This renders these compounds the OFF–ON–OFF type of pH-dependent fluorescent sensor. The thermodynamic stability and aqueous coordination chemistry of the chelator with the said lanthanide ions have also been probed by potentiometric, UV–visible and fluorescence spectrophotometric method. TAME5OX has been found to form two protonated complexes [Ln(H{sub 5}L)]{sup 5+} and [Ln(H{sub 4}L)]{sup 4+} below pH 2.5 with both metal ions, which consecutively deprotonates through one proton process with rise of pH. The formation constants (log β{sub 11n}) of neutral complexes have been determined to be 33.51 and 32.16 with pLn (pLn=−log[Ln{sup 3+}]) values of 16.14 and 19.48 for Eu{sup 3+} and Tb{sup 3+} ions, respectively, calculated at pH 7.4, indicating TAME5OX is a good lanthanide synthetic chelator. The emission lifetimes of the Eu{sup 3+} and Tb{sup 3+} complexes recorded in D{sub 2}O and H{sub 2}O suggest the presence

  13. Synthesis of High Molecular Weight Inverse Emulsion Polymer Resistant to Temperature and Salt%高相对分子质量反相乳液耐温抗盐聚合物合成研究

    Institute of Scientific and Technical Information of China (English)

    雷齐玲

    2015-01-01

    在概述反相乳液聚合物合成进展的基础上,对提高其相对分子质量和改进耐温性进行了研究.通过优选耐温单体提高产物耐温性,通过优选合成条件提高产物相对分子质量.选用丙烯酸(AA)、丙烯酰胺(AM) 和2-丙烯酰氨基-2-甲基丙磺酸(AMPS) 为水溶性单体,以液体石蜡为油相,以过硫酸盐为引发剂,采用反相乳液共聚法合成了AA/AM/AMPS反相乳液耐温抗盐聚合物.试验发现,乳化剂最佳用量为8%,最佳油水比为1:1,最佳引发温度为20℃,在此条件下合成的反相乳液耐温抗盐聚合物相对分子质量可达1500×104.在90℃矿化度为32868mg/L的水中,7天内产物黏度保留率较常规聚丙烯酰胺高出59%; 溶解时间仅为常规聚丙烯酰胺的1/7,具有较好的耐温抗盐性能和溶解性.研究结果对现阶段反相乳液聚合物性能的提高具有借鉴作用.%Summing up the progress of inverse emulsion polymer synthesis, enhancing molecular weight and high temperature resistance was probed into in this paper. Temperature resistance of product was enhanced by selecting temperature resistant monomer, and molecular weight of product by optimizing synthesis conditions. Selecting acrylic acid (AA), acrylamide (AM), 2- acrylamido-2-methylpropane sulfonic acid (AMPS) as water-soluble monomer, liquid paraffin as oil phase, the persulfate as initiator, inverse emulsion copolymerization was used for synthesizing AA / AM / AMPS inverse emulsion poly-mer resistant to temperature and salt. Test showed that the optimum amount of emulsifier was 8%, the best oil-water ratio was 1. 1:1, the best initiation temperature was 20℃, and the molecular weight of inverse emulsion polymer resistant to tem-perature and salt could reach 1500×104. In water of 90℃and 32868mg/L salinity, the product viscosity retention rate was 59% higher than conventional polyacrylamide within 7 days, but dissolution time was only 1/7 of conventional polyacrylam

  14. 抗盐降失水剂HTF-110L的研制及性能评价%Synthesis and Properties Evaluation of Salt Resistant Fluid Loss Additive HTF-110L

    Institute of Scientific and Technical Information of China (English)

    郭锦棠; 骆成; 余前峰; 刘硕琼; 靳建州; 于永金

    2015-01-01

    针对目前固井降失水剂所存在的抗高温抗盐能力差、温度适应范围窄的问题,以2-丙烯酰胺基-2-甲基丙磺酸(AMPS)、丙烯酰胺(AM)、丙烯酸(AA)为主要单体,并引入新型多羟基羧酸化合物,采用自由基水溶液共聚合成了抗温、抗盐、温度适应范围广的降失水剂 HTF-110L.采用正交实验法,优选出了最佳合成工艺条件.采用红外光谱、核磁共振和热失重分析对共聚物进行了表征.结果表明:各单体成功参与聚合,聚合产物为目标产物,降失水剂耐温性能良好;由于在共聚物分子链中引入了多种功能性基团,合成的降失水剂在淡水、盐水水泥浆中具有良好的降失水性能;降失水剂分散性弱,在高温条件下对水泥浆的稳定性影响较小,低温条件下缓凝性弱,对水泥石强度发展无不良影响,具有较宽的温度适用范围;降失水剂与其他油井水泥外加剂配伍性好,以 HTF-110L 为主剂的低密度、高密度水泥浆体系具有失水量小、流变性好、稳定性佳、过渡时间短、抗压强度高等特点,综合性能优异.%The currently used cement fluid loss additive has the problems of weak salt tolerance,poor thermal stabil-ity and narrow range of temperature adaptation. To solve the problems,a novel high temperature-resistant,salt-tolerant and wide-range-of-temperature-applied fluid loss additive HTF-110L was synthesized by using the monomers of 2-acrylamido-2-methylpropane sulfonic acid(AMPS),acrylamide(AM),acrylic acid(AA)and poly-hydroxyls carboxylic acid with the method of aqueous solution polymerization. Optimal synthesizing process conditions of HTF-110L were extracted by orthogonal experiment. The synthetic fluid loss additive was characterized by Fourier trans-form infrared spectroscopy,proton nuclear magnetic resonance spectroscopy and thermogravimetric analysis. The analysis results reveal that the polymer is the target