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Sample records for 2-methylpropane

  1. Density and viscosity of mixtures of nitrobenzene with methanol, ethanol, propan-1-ol, propan-2-ol, butan-1-ol, 2-methylpropan-1-ol, and 2-methylpropan-2-ol at 298.15 and 303.15 K

    SciTech Connect

    Nikam, P.S.; Jadhav, M.C.; Hasan, M.

    1995-07-01

    Densities and viscosities of mixtures of nitrobenzene with methanol, ethanol, propan-1-ol, propan-2-ol, butan-1-ol, 2-methylpropan-1-ol, and 2-methylpropan-2-ol were measured at 298.15 and 303.15 K. From these measurements, the excess volumes (V{sup E}) and deviation in viscosity ({delta}{eta}) were calculated. These results were fitted to the Redlich-Kister polynomial.

  2. Density and viscosity of mixtures of dimethyl sulfoxide + methanol, + ethanol, + propan-1-ol, + propan-2-ol, + butan-1-ol, + 2-methylpropan-1-ol, and + 2-methylpropan-2-ol at 298.15 K and 303.15 K

    SciTech Connect

    Nikam, P.S.; Jadhav, M.C.; Hasan, M.

    1996-09-01

    Densities and viscosities have been measured for the binary mixtures of dimethyl sulfoxide + methanol, + ethanol, + propan-1-ol, + propan-2-ol, + butan-1-ol, + 2-methylpropan-1-ol, and + 2-methylpropan-2-ol at 298.15 K and 303.15 K. From these results, the excess molar volume (V{sup E}) and deviation in viscosity ({Delta}{eta}) have been computed. These properties are used to calculate regression coefficients of the Redlich-Kister equation.

  3. Synthesis and properties of poly(methyl methacrylate-2-acrylamido-2-methylpropane sulfonic acid)/PbS hybrid composite

    SciTech Connect

    Preda, N.; Rusen, E.; Musuc, A.; Enculescu, M.; Matei, E.; Marculescu, B.; Fruth, V.; Enculescu, I.

    2010-08-15

    The synthesis of a new hybrid composite based on PbS nanoparticles and poly(methyl methacrylate-2-acrylamido-2-methylpropane sulfonic acid) [P(MMA-AMPSA)] copolymer is reported. The chemical synthesis consists in two steps: (i) a surfactant-free emulsion copolymerization between methyl methacrylate and 2-acrylamido-2-methylpropane sulfonic acid and (ii) the generation of PbS particles in the presence of the P(MMA-AMPSA) latex, from the reaction between lead nitrate and thiourea. The composite was studied by scanning electron microscopy (SEM), X-ray diffraction, FTIR spectroscopy, thermogravimetric analysis and differential scanning calorimetry. The microstructure observed using SEM proves that the PbS nanoparticles are well dispersed in the copolymer matrix. The X-ray diffraction measurements demonstrate that the PbS nanoparticles have a cubic rock salt structure. It was also found that the inorganic semiconductor nanoparticles improve the thermal stability of the copolymer matrix.

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

    PubMed

    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

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

    PubMed

    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. PMID:26506981

  6. C4H9I 2-Iodo-2-methylpropane

    NASA Astrophysics Data System (ADS)

    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'.

  7. Thermodynamic properties of {Delta}H{sub f 298}{degree}, S{sub 298}{degree}, and C{sub p}(T) for 2-fluoro-2-methylpropane, {Delta}H{sub f 298}{degree} of fluorinated ethanes, and group additivity for fluoroalkanes

    SciTech Connect

    Yamada, Takahiro; Bozzelli, J.W.

    1999-09-09

    G2(MP2) composite calculations are performed to obtain thermodynamic properties ({Delta}H{sub f 298}{degree}, S{sub 298}{degree} and C{sub p}(T)'s) of 2-fluoro-2-methylpropane. {Delta}H{sub f 298}{degree} is calculated from the G2(MP2) calculated enthalpy of reaction ({Delta}H{sub rxn 298}{degree}) and use of isodesmic reactions. Standard entropy (S{sub 298}{degree} in cal/(mol{center{underscore}dot}K)) and heat capacities (C{sub p}(T)'s in cal/(mol{center{underscore}dot}K)) are calculated using the rigid-rotor--harmonic-oscillator approximation with direct integration over energy levels of the intermolecular rotation potential energy curve. These thermodynamic properties are used to estimate data for the C/C3/F group. Enthalpies of formation ({Delta}H{sub f 298}{degree} in kcal/mol) for 1,2-difluoroethane ({minus}102.7), 1,1,2-trifluoroethane ({minus}156.9), 1,1,2,2- and 1,1,1,2-tetrafluoroethane (209.6 and 213.3), and pentafluoroethane ({minus}264.1), are calculated using total energies obtained from G2(MP2) composite ab initio methods. Isodesmic reactions with existing literature values of {Delta}H{sub f 298}{degree} for ethane, 1-fluoroethane, 1,1-difjuoroethane and 1,1,1-trifluoroethane are used. Fluorine/fluorine interaction terms, F/F, 2F/F, 3F/F, 2F/2F, and 3F/2F, where ``/'' indicates interaction for alkane compounds, for {Delta}H{sub f 298}{degree} are reevaluated based on {Delta}H{sub f 298}{degree} of the above five fluoroethanes. Thermodynamic properties ({Delta}H{sub f 298}{degree}, S{sub 298}{degree} and C{sub p}(T)'s (300 {le} T/K {le} 1500)) for fluorinated carbon groups, C/C3F, C/C2/F/H, C/C2/F2, are calculated using data from ab initio methods and existing literature data. Fluorine-methyl (alkyl) group additivity corrections for gauche interactions are also evaluated.

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

    NASA Astrophysics Data System (ADS)

    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.

  9. THERMODYNAMIC PROPERTIES HF 298, S 298, AND CP(T) FOR 2-FLUORO-2-METHYLPROPANE, HF 298 OF FLUORINATED ETHANES, AND GROUP ADDITIVITY FOR FLUOROALKANES. (R824970)

    EPA Science Inventory

    The perspectives, information and conclusions conveyed in research project abstracts, progress reports, final reports, journal abstracts and journal publications convey the viewpoints of the principal investigator and may not represent the views and policies of ORD and EPA. Concl...

  10. Rate of Hydrolysis of Tertiary Halogeno Alkanes

    ERIC Educational Resources Information Center

    Pritchard, D. R.

    1978-01-01

    Describes an experiment to measure the relative rate of hydrolysis of the 2-x-2 methylpropanes, where x is bromo, chloro or iodo. The results are plotted on a graph from which the relative rate of hydrolysis can be deduced. (Author/GA)

  11. A two-dimensional homospin Cu(II) ferrimagnet featuring S-shaped hexanuclear secondary building blocks.

    PubMed

    Chen, Zilu; Liu, Long; Wang, Yifei; Zou, Huahong; Zhang, Zhong; Liang, Fupei

    2014-06-14

    The decomposition of 2-(1-hydroxy-2-methylpropan-2-yl-imino)-1,2-diphenylethanone in the presence of copper acetate promoted the formation of a two-dimensional homospin Cu(II) ferrimagnet featuring S-shaped hexanuclear secondary building blocks and a new pentanodal topology. PMID:24676556

  12. Well cementing method using an am/amps fluid loss additive blend

    SciTech Connect

    Boncan, V.G.; Gandy, R.

    1986-12-30

    A method is described of cementing a wellbore, comprising the steps of: mixing together a hydraulic cement, water in an amount to produce a pumpable slurry, and a non-retarding fluid loss additive blend. The blend comprises a copolymer of acrylamide and 2-acrylamide-2-methylpropane sulfonate, the sodium salt of naphthalene formaldehyde sulfonate, and polyvinylpyrrolidone polymer; pumping the cement slurry to the desired location in the wellbore; and allowing the cement slurry to harden to a solid mass.

  13. [Analysis of C4 fluoride compounds in alkylation materials by gas chromatography/flame ionization detection (GC/FID)].

    PubMed

    Han, Jianghua; Yang, Haiying

    2004-09-01

    A method for the analysis of C4 fluoride compounds in alkylation materials was developed by GC/FID. In order to confirm the presence of C4 fluoride compounds in alkylation materials, 1-fluorobutane, 2-fluorobutane and 2-fluoro-2-methylpropane were synthesized and analysed by GC/FID, gas chromatography/atomic emission detection (GC/AED) and gas chromatography/mass spectrometry (GC/MS). The results showed that only 2-fluoro-2-methylpropane existed in the alkylation materials. Based on the properties of element response on GC/AED, the calibration factors of C4 fluoride compounds on GC/FID were calculated. The analysis was performed on OV-225 (50 m x 0.25 mm i. d. x 0.25 microm) and SE-54 (44 m x 0.22 mm i. d. x 0.25 microm) columns, which were connected in series. FID was used as the detector. In quantitative analysis of the alkylation materials the methods of calibration normalization and indirect external standard were suggested. The calibration curves were linear (r = 0.992) in the concentration range of 156 - 700 microL/L. The minimum detection limit of 2-fluoro-2-methylpropane in real samples was 150 microL/L (S/N = 3). The method is simple, reproducible and easy to be applied. The other components in the alkylation materials can also be analyzed if the calibration normalization method is used. PMID:15706940

  14. Release of volatile organic compounds (VOCs) from the lung cancer cell line CALU-1 in vitro

    PubMed Central

    Filipiak, Wojciech; Sponring, Andreas; Mikoviny, Tomas; Ager, Clemens; Schubert, Jochen; Miekisch, Wolfram; Amann, Anton; Troppmair, Jakob

    2008-01-01

    Background The aim of this work was to confirm the existence of volatile organic compounds (VOCs) specifically released or consumed by lung cancer cells. Methods 50 million cells of the human non-small cell lung cancer (NSCLC) cell line CALU-1 were incubated in a sealed fermenter for 4 h or over night (18 hours). Then air samples from the headspace of the culture vessel were collected and preconcentrated by adsorption on solid sorbents with subsequent thermodesorption and analysis by means of gas chromatography mass spectrometry (GC-MS). Identification of altogether 60 compounds in GCMS measurement was done not only by spectral library match, but also by determination of retention times established with calibration mixtures of the respective pure compounds. Results The results showed a significant increase in the concentrations of 2,3,3-trimethylpentane, 2,3,5-trimethylhexane, 2,4-dimethylheptane and 4-methyloctane in the headspace of CALU-1 cell culture as compared to medium controls after 18 h. Decreased concentrations after 18 h of incubation were found for acetaldehyde, 3-methylbutanal, butyl acetate, acetonitrile, acrolein, methacrolein, 2-methylpropanal, 2-butanone, 2-methoxy-2-methylpropane, 2-ethoxy-2-methylpropane, and hexanal. Conclusion Our findings demonstrate that certain volatile compounds can be cancer-cell derived and thus indicative of the presence of a tumor, whereas other compounds are not released but seem to be consumed by CALU-1 cells. PMID:19025629

  15. Metabolism of 2-Methylpropene (Isobutylene) by the Aerobic Bacterium Mycobacterium sp. Strain ELW1

    PubMed Central

    Kottegoda, Samanthi; Waligora, Elizabeth

    2015-01-01

    An aerobic bacterium (Mycobacterium sp. strain ELW1) that utilizes 2-methylpropene (isobutylene) as a sole source of carbon and energy was isolated and characterized. Strain ELW1 grew on 2-methylpropene (growth rate = 0.05 h−1) with a yield of 0.38 mg (dry weight) mg 2-methylpropene−1. Strain ELW1 also grew more slowly on both cis- and trans-2-butene but did not grow on any other C2 to C5 straight-chain, branched, or chlorinated alkenes tested. Resting 2-methylpropene-grown cells consumed ethene, propene, and 1-butene without a lag phase. Epoxyethane accumulated as the only detected product of ethene oxidation. Both alkene consumption and epoxyethane production were fully inhibited in cells exposed to 1-octyne, suggesting that alkene oxidation is initiated by an alkyne-sensitive, epoxide-generating monooxygenase. Kinetic analyses indicated that 1,2-epoxy-2-methylpropane is rapidly consumed during 2-methylpropene degradation, while 2-methyl-2-propen-1-ol is not a significant metabolite of 2-methylpropene catabolism. Degradation of 1,2-epoxy-2-methylpropane by 2-methylpropene-grown cells led to the accumulation and further degradation of 2-methyl-1,2-propanediol and 2-hydroxyisobutyrate, two sequential metabolites previously identified in the aerobic microbial metabolism of methyl tert-butyl ether (MTBE) and tert-butyl alcohol (TBA). Growth of strain ELW1 on 2-methylpropene, 1,2-epoxy-2-methylpropane, 2-methyl-1,2-propanediol, and 2-hydroxyisobutyrate was fully inhibited when cobalt ions were omitted from the growth medium, while growth on 3-hydroxybutyrate and other substrates was unaffected by the absence of added cobalt ions. Our results suggest that, like aerobic MTBE- and TBA-metabolizing bacteria, strain ELW1 utilizes a cobalt/cobalamin-dependent mutase to transform 2-hydroxyisobutyrate. Our results have been interpreted in terms of their impact on our understanding of the microbial metabolism of alkenes and ether oxygenates. PMID:25576605

  16. Synthesis and evaluation of iron-doped titania/silane based hydrogel for the adsorptional photocatalytic degradation of Victoria blue under visible light.

    PubMed

    Anirudhan, Thayyath S; Divya, Peethambaran L; Nima, Jayachandran; Sandeep, Sadanandan

    2014-11-15

    Novel photocatalyst, poly(itaconic acid-co-2-acrylamido-2-methylpropane-1-sulfonic acid) iron doped titania/silane was successfully prepared by the polymerization of iron doped titania/silane and two functional monomers, itaconic acid and 2-acrylamido-2-methylpropane-1-sulfonic acid in aqueous solution using ethylene glycol dimethacrylate as cross-linker and benzoylperoxide as initiator. The sample was characterized using scanning electron microscopy (SEM), X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR) and Diffuse reflectance spectroscopy (DRS) techniques. Effects of various factors like pH, adsorbent dose, contact time, and ionic strength on the adsorption capacity of photocatalyst for Victoria blue (VB) were studied by batch adsorption experiments. The kinetic data were found to follow pseudo-second-order kinetic model with low chi square, χ(2) values and R(2) values closer to unity. The equilibrium data were in well agreement with Langmuir isotherm model and maximum adsorption capacity was found to be 153.89 mg/g. The swelling capacity of the adsorbent with changes in pH, time and temperature was also investigated. The kinetics of photocatalytic degradation of VB by the photocatalyst found to follow first-order kinetics. The regeneration and repeated use of photocatalyst were also examined upto four cycles. The prepared photocatalyst was found to be efficient photocatalyst-cum-adsorbent for the degradation of VB from aqueous solutions under solar light. PMID:25168582

  17. Amino-functionalized (meth)acryl polymers by use of a solvent-polarity sensitive protecting group (Br-t-BOC)

    PubMed Central

    Tabatabai, Monir; Herrmann, Markus

    2016-01-01

    Summary We describe the synthesis of bromo-tert-butyloxycarbonyl (Br-t-BOC)-amino-protected monomers 2-((1-bromo-2-methylpropan-2-yl)oxycarbonylamino)ethyl (meth)acrylate 3a,b. For this purpose, 2-isocyanatoethyl (meth)acrylate 1a,b was reacted with 1-bromo-2-methylpropan-2-ol (2a). The free radical polymerization of (Br-t-BOC)-aminoethyl (meth)acrylates 3a,b yielded poly((Br-t-BOC)-aminoethyl (meth)acrylate) 6a,b bearing protected amino side groups. The subsequent solvolysis of the Br-t-BOC function led to the new polymers poly(2-aminoethyl (meth)acrylate) 8a,b with protonated free amino groups. The monomers and the resulting polymers were thoroughly characterized by 1H NMR, IR, GPC and DSC methods. The kinetics of the deprotection step was followed by 1H NMR spectroscopy. The solvent polarity and neighboring group effects on the kinetics of deprotection are discussed. PMID:26977183

  18. Amino-functionalized (meth)acryl polymers by use of a solvent-polarity sensitive protecting group (Br-t-BOC).

    PubMed

    Ritter, Helmut; Tabatabai, Monir; Herrmann, Markus

    2016-01-01

    We describe the synthesis of bromo-tert-butyloxycarbonyl (Br-t-BOC)-amino-protected monomers 2-((1-bromo-2-methylpropan-2-yl)oxycarbonylamino)ethyl (meth)acrylate 3a,b. For this purpose, 2-isocyanatoethyl (meth)acrylate 1a,b was reacted with 1-bromo-2-methylpropan-2-ol (2a). The free radical polymerization of (Br-t-BOC)-aminoethyl (meth)acrylates 3a,b yielded poly((Br-t-BOC)-aminoethyl (meth)acrylate) 6a,b bearing protected amino side groups. The subsequent solvolysis of the Br-t-BOC function led to the new polymers poly(2-aminoethyl (meth)acrylate) 8a,b with protonated free amino groups. The monomers and the resulting polymers were thoroughly characterized by (1)H NMR, IR, GPC and DSC methods. The kinetics of the deprotection step was followed by (1)H NMR spectroscopy. The solvent polarity and neighboring group effects on the kinetics of deprotection are discussed. PMID:26977183

  19. Identification and characterization of the aroma-impact components of Thai fish sauce.

    PubMed

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

    2015-03-18

    Comprehensive analysis of the potent odorants in Thai premium fish sauce samples was accomplished by use of complementary volatile isolation methods combined with gas chromatography-olfactometry (GC-O) and GC-mass spectrometry. Odorants of intermediate and low volatility were determined by direct solvent extraction/solvent-assisted flavor evaporation (DSE-SAFE) and aroma extract dilution analysis (AEDA). Meanwhile, static headspace dilution analysis (SHDA) and headspace solid-phase microextraction (H-SPME) were used to determine the highly volatile odorants. Results of AEDA indicated the importance (log3FD factor≥6) of five acidic odorants (butanoic acid, 3-methylbutanoic acid, 4-hydroxy-2,5-dimethyl-3(2H)-furanone, 4-hydroxy-2-ethyl-5-methyl-3(2H)-furanone, and 2-phenylacetic acid) and four neutral/basic odorants (3-methylbutanal, (Z)-1,5-octadien-3-one, phenylacetaldehyde, and o-aminoacetophone). Results of SHDA indicated the predominant (log3FD factors≥5) headspace odorants were methanethiol, 2-methylpropanal, 2-methylbutanal, 3-methylbutanal, dimethyl trisulfide, 3-(methylthio)propanal, and butanoic acid. Concentrations for 21 odorants were determined by stable isotope dilution analysis (SIDA), and their odor-activity values (OAVs) were calculated. Among these, methanethiol, 2-methylpropanal, 3-methylbutanal, dimethyl trisulfide, 3-(methylthio)propanal, and butanoic acid had the highest OAVs (>500). Results of aroma recombination and omission studies revealed the importance of acids, aldehydes, and sulfur-containing compounds to the overall aroma of the Thai fish sauce. PMID:25730550

  20. Solvent effects on kinetics of an heteroatomic nucleophilic substitution reaction in ionic liquid and molecular solvents mixtures

    NASA Astrophysics Data System (ADS)

    Salari, Hadi; Pedervand, Mohsen; Sadeghzadeh-Darabi, Faramarz; Gholami, Mohammad Reza

    2013-12-01

    Rate constants, k A, for the aromatic nucleophilic substitution reaction of 2-chloro-3,5-dinitropyridine with aniline were determined in different compositions of 2-propanol mixed with hexane, benzene, and 2-methylpropan-2-ol and 1-ethyl-3-methylimidazolium ethylsulfate ([Emim][EtSO4]) with dimethyl sulfoxide at 25°C. The obtained rate constants of the reaction in pure solvents are in the following order: 2-methylpropan-2-ol > dimethyl sulfoxide > 2-propanol > hexane > benzene > [Emim][EtSO4]. Molecularmicroscopic solvent parameters corresponding to the selected binary mixtures were utilized to study the kinetics of a nucleophilic substitution reaction in order to investigate and compare the effects of the solvents on a chemical process. The influence of solvent parameters including normalized polarity ( E {/T N }), dipolarity/polarizability (π*), hydrogen bond donor acidity (α), and hydrogen bond acceptor basicity (β) on the second-order rate constants were investigated and multiple linear regressions gave much better results with regard to single parameter regressions. The dipolarity/polarizability of media has a positive effect in all mixtures regarding zwitterionic character of the reaction intermediate and the hydrogen bond acceptor basicity of the solvent by stabilizing of activated complex increases the reaction rate.

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

    PubMed

    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

  2. Use of gas chromatography-olfactometry to identify key odorant compounds in dark chocolate. Comparison of samples before and after conching.

    PubMed

    Counet, Christine; Callemien, Delphine; Ouwerx, Caroline; Collin, Sonia

    2002-04-10

    After vacuum distillation and liquid-liquid extraction, the volatile fractions of dark chocolates were analyzed by gas chromatography-olfactometry and gas chromatography-mass spectrometry. Aroma extract dilution analysis revealed the presence of 33 potent odorants in the neutral/basic fraction. Three of these had a strong chocolate flavor: 2-methylpropanal, 2-methylbutanal, and 3-methylbutanal. Many others were characterized by cocoa/praline-flavored/nutty/coffee notes: 2,3-dimethylpyrazine, trimethylpyrazine, tetramethylpyrazine, 3(or 2),5-dimethyl-2(or 3)-ethylpyrazine, 3,5(or 6)-diethyl-2-methylpyrazine, and furfurylpyrrole. Comparisons carried out before and after conching indicate that although no new key odorant is synthesized during the heating process, levels of 2-phenyl-5-methyl-2-hexenal, Furaneol, and branched pyrazines are significantly increased while most Strecker aldehydes are lost by evaporation. PMID:11929301

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

    NASA Astrophysics Data System (ADS)

    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.

  4. Adsorption of water to double-network polymers having a hierarchical structure

    NASA Astrophysics Data System (ADS)

    Tominaga, Taiki; Takata, Shin-ichi; Suzuki, Jun-ichi; Aizawa, Kazuya; Seto, Hideki; Arai, Masatoshi

    2014-04-01

    Double-network hydrogels (DN-gels) have cross-linked aqueous polymer networks which result in unique mechanical properties [1,2]. Although the structure of the hydrophilic polymer networks have been previously determined [3,4,5], it was not clear how water molecules are adsorbed to the polymer network. We prepared freeze-dried DN-gels (DN-polymers) made of polyacrylamide and sodium salt of poly(2-acrylamido-2-methylpropane sulfonic acid), and small-angle neutron scattering (SANS) experiments were conducted to determine the humidity dependence of the nanoscale structure. The SANS results show that water molecules adsorb on larger structures than the mesh size of polymer networks at low relative humidity (RH), and adsorb gradually on the segmental scale of polymers with increasing RH.

  5. Solubility of anthracene in binary alkane + methyl tert-butyl ether solvent mixtures at 298.15 K

    SciTech Connect

    McHale, M.E.R.; Kauppila, A.S.M.; Acree, W.E. Jr.

    1996-09-01

    Experimental solubilities are reported for anthracene dissolved in seven binary mixtures containing methyl tert-butyl ether (also called 2-methoxy-2-methylpropane) with hexane, heptane, octane, cyclohexane, methylcyclohexane, 2,2,4-trimethylpentane, and tert-butylcyclohexane (also called (1,1-dimethylethyl)-cyclohexane) at 25 C. Results of these measurements are used to test two mathematical representations based upon the combined nearly ideal binary solvent (NIBS)/Redlich-Kister equation and modified Wilson model. For the seven systems studied, both equations were found to provide an accurate mathematical representation of the experimental data, with an overall average absolute deviation between measured and calculated values being on the order of 0.5%.

  6. Experimental and theoretical studies on formation and degradation of chloro organic compounds.

    PubMed

    Cysewski, Piotr; Gackowska, Alicja; Gaca, Jerzy

    2006-03-01

    Studies on oxidation of tert-butyl ethers in the presence of chloride ions proved that acid medium favoured formation of chloro organic compounds. 1,2-Dichloro-2-methylpropane, 3-chloro-2-chloromethylpropene were identified among the reaction products. Presence of these compounds was identified both in the case when methyl-tert-butyl ether (MTBE) and ethyl-tert-butyl ether (ETBE) were subjected to reaction. Reaction products were analysed by gas chromatography method with application of -FID, -MS and -AED detectors. On the basis of experimental data, the path of tert-butyl ethers conversion to dichloro products was proposed. It was found that the identified chloro derivatives could be formed both by ionic and radical reactions. In order to confirm this thesis for the proposed scheme of reaction, the theoretical calculations of molecular simulation of the reaction paths were performed. PMID:16146644

  7. Polymerization of novel methacrylated anthraquinone dyes

    PubMed Central

    Dollendorf, Christian; Kreth, Susanne Katharina; Choi, Soo Whan

    2013-01-01

    Summary 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-methacryloxyethyl)phenylamino)-1,4-dihydroxyanthraquinone (2), blue 1,4-bis(4-((2-methacryloxyethyl)oxy)phenylamino)anthraquinone (6) and red 1-((2-methacryloxy-1,1-dimethylethyl)amino)anthraquinone (12), as well as 1-((1,3-dimethacryloxy-2-methylpropan-2-yl)amino)anthraquinone (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. PMID:23503994

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

    NASA Astrophysics Data System (ADS)

    Rittich, Bohuslav; Španová, Alena; Šálek, Petr; Němcová, Petra; Trachtová, Štěpánka; Horák, Daniel

    2009-05-01

    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.

  9. Magnetic Properties of [Ni(C_4H_12N_2)_2(μ-N_3)]_n(ClO_4)_n: A Quasi-One-Dimensional Antiferromagnetic S = 1 Ladder-Like Material.

    NASA Astrophysics Data System (ADS)

    Ward, B. H.; Talham, D. R.; Granroth, G. E.; Meisel, M. W.

    1997-03-01

    [Ni(1,2-diamino-2-methylpropane)_2(μ-N_3)]_n(ClO_4)n forms a helicoidal nickel(II)-azido skeleton due to the cis position of the azido bridging ligands( J. Ribas et al.), Inorg. Chem. 34 (1995) 4986.. The resulting S = 1 ladder-like structure is reminiscent of the one possessed by the S = 1/2 material Cu_2(C_5H_12N_2)_2Cl_4.( B. Chiari et al., Inorg. Chem.) 29 (1990) 1172.^,( P.R. Hammer and D.H. Reich, J. Appl. Phys.) 79 (1996) 5392. The magnetic properties of powder, polycrystalline, and oriented single crystal samples have been measured down to 2 K in fields up to 5 T, where no evidence for long-range order is observed. Various possible theoretical fits of the data will be presented, and magnetic and thermodynamic measurements at millikelvin temperatures are in progress.

  10. Synthesis and Low Temperature Spectroscopic Observation of 1,3,5-Trioxane-2,4,6-Trione: The Cyclic Trimer of Carbon Dioxide.

    PubMed

    Rodig, Michael J; Snow, Arthur W; Scholl, Paul; Rea, Simon

    2016-07-01

    1,3,5-Trioxane-2,4,6-trione (cyclic trimer of CO2) is the product of a four-step synthesis: chlorination of isobutyraldehyde; cyclotrimerization of 2-chloro-2-methylpropanal; dehydochlorination of 2,4,6-tris(2-chloropropan)-2-yl-1,3,5-trioxane; ozonolysis at -80 °C of 2,4,6-tri(propan-2-ylidene)-1,3,5-trioxane. This trioxane-trione is detected in solution at temperatures between -80 to -40 °C, and its conversion to CO2 is monitored by (13)C NMR and FTIR. The CO2 trimer has a half-life of approximately 40 min at -40 °C. PMID:27183100

  11. Water-soluble copolymers. IV. Random copolymers of acrylamide with sulfonated comonomers

    SciTech Connect

    McCormick, C.L.; Chen, G.S.

    1982-03-01

    Random copolymers of acrylamide with sodium-2-sulfoethyl methacrylate and with sodium-2-acrylamido-2-methylpropane sulfonate were synthesized in aqueous solutions utilizing persulfate initiators. Copolymer compositions were determined by elemental analysis and by infrared spectroscopic methods. Monomer reactivity ratios were calculated using Fineman-Ross, Kelen-Tuedos, and/or Mayo-Lewis techniques at appropriate conversions. The copolymer microstructure, including mean sequence length distributions, was calculated from reactivity ratios. Membrane osmometry and viscometry measurements were utilized to estimate molecular weight and size. The large dimensions of these polyelectrolytes in aqueous solutions, as well as their inherent hydrogen bonding capacity and pseudoplasticity, make these copolymers excellent candidates for application as mobility control agents in enhanced oil recovery.

  12. Foxo3a Inhibitors of Microbial Origin, JBIR-141 and JBIR-142.

    PubMed

    Kawahara, Teppei; Kagaya, Noritaka; Masuda, Yuichi; Doi, Takayuki; Izumikawa, Miho; Ohta, Kumiko; Hirao, Atsushi; Shin-ya, Kazuo

    2015-11-01

    JBIR-141 (1) and JBIR-142 (2) were discovered as potent Foxo3a inhibitors that consist of three quite unique substructures, a 1-((dimethylamino)ethyl)-5-methyl-4,5-dihydrooxazole-4-carboxylic acid that is originated from Ala-Thr amino acid residues, a 3-acetoxy-4-amino-7-(hydroxy(nitroso)amino)-2,2-dimethylheptanoic acid, and an α-acyl tetramic acid fused with a 2-methylpropan-1-ol moiety. Their structures involving absolute configurations were determined by spectroscopic data, chemical degradation, anisotropy methods, and LC-MS analyses of diastereomeric derivatives. Compounds 1 and 2 exhibited specific inhibition against Foxo3a transcriptional activity with IC50 values of 23.1 and 166.2 nM, respectively. PMID:26493489

  13. Crystal structures of 6-[(2-hydroxy-1,1-bishydroxymethylethylamino)methylene]-2, 4-dinitrocyclohexa-2, 4-dienone hydrate and complexes of copper(II) chloride and copper(II) nitrate with this ligand

    SciTech Connect

    Chumakov, Yu. M. Tsapkov, V. I.; Jeanneau, E.; Bocelli, G.; Luneau, D.

    2006-07-15

    The crystal structures of 6-[(2-hydroxy-1,1-bishydroxymethylethylamino)methylene]-2, 4-dinitrocyclohexa-2, 4-dienone hydrate L . H{sub 2}O (I), chloro-(2-hydroxymethyl-2-methylpropane-1,3-diol-2-iminomethyl-4, 6-dinitrophenolo)aquacopper hydrate [Cu(H{sub 2}O)(L-H)Cl] . H{sub 2}O (II), and (2-hydroxymethyl-2-methylpropane-1,3-diol-2-iminomethyl-4,6-dinitrophenolo) aquacopper nitrate [Cu(H{sub 2}O)(L-H)]NO{sub 3} (III) are determined using X-ray diffraction. It is established that the salicylidene fragment of azomethine L in the structure of compound I is in a quinoid tautomeric form. In the crystal, molecules L and water molecules are joined together by hydrogen bonds into two-dimensional layers aligned parallel to the (010) plane. The copper atom in the structure of compound II coordinates the singly deprotonated tridentate molecule L (whose salicylidene fragment is in a benzenoid form), the chlorine ion, and the water molecule. The coordination polyhedron of the central copper atom is a distorted tetragonal pyramid. In the structure of compound III, the polymer chains are formed through the coordination bonds of the copper atom with two oxygen atoms of the amino alcohol fragment of azomethine L of the neighboring complex, which is related to the initial complex by the translation along the x axis. The coordination polyhedron of the central atom is an elongated tetragonal bipyramid. Polymers and nitro groups form a three-dimensional framework through hydrogen bonds.

  14. Drilling fluids containing amps, acrylic acid, itaconic acid polymer

    SciTech Connect

    Bardoliwalla, D.F.

    1987-10-13

    This patent describes an aqueous drilling fluid having present in an amount sufficient to reduce fluid loss of the drilling fluid, at least one polymer of (1) from about 5% to about 50% by weight of 2-acrylamido-2-methylpropane sulfonic acid and (2) from about 95% to about 50% by weight of a second component, there being from 100% to about 80% by weight of acrylic acid and from 0% by weight to about 20% by weight of itaconic acid in the second component. The polymer has a weight average molecular weight of between about 50,000 to about 1,000,000 being in its free acid or partially or completely neutralized form and being at least water dispersible. A method is described of drilling a well into a subterranean formation in which an aqueous drilling fluid is circulated into the well. The step of circulating the drilling fluid contains in an amount sufficient to reduce fluid loss of the drilling fluid, at least one polymer of (1) from about 5% to about 50% by weight of 2-acrylamido-2-methylpropane sulfonic acid and (2) from about 95% to about 50% by weight of a second component. There is from 100% to about 80% by weight of acrylic acid and from 0% by weight to about 20% by weight of itaconic acid in the second component. The polymer has weight average molecular weight of between about 50,000 to about 1,000,000 in its free acid or partially or completely neutralized form and is at least water dispersible.

  15. Impact of higher alcohols blended in gasoline on light-duty vehicle exhaust emissions.

    PubMed

    Ratcliff, Matthew A; Luecke, Jon; Williams, Aaron; Christensen, Earl; Yanowitz, Janet; Reek, Aaron; McCormick, Robert L

    2013-12-01

    Certification gasoline was splash blended with alcohols to produce four blends: ethanol (16 vol%), n-butanol (17 vol%), i-butanol (21 vol%), and an i-butanol (12 vol%)/ethanol (7 vol%) mixture; these fuels were tested in a 2009 Honda Odyssey (a Tier 2 Bin 5 vehicle) over triplicate LA92 cycles. Emissions of oxides of nitrogen, carbon monoxide, non-methane organic gases (NMOG), unburned alcohols, carbonyls, and C1-C8 hydrocarbons (particularly 1,3-butadiene and benzene) were determined. Large, statistically significant fuel effects on regulated emissions were a 29% reduction in CO from E16 and a 60% increase in formaldehyde emissions from i-butanol, compared to certification gasoline. Ethanol produced the highest unburned alcohol emissions of 1.38 mg/mile ethanol, while butanols produced much lower unburned alcohol emissions (0.17 mg/mile n-butanol, and 0.30 mg/mile i-butanol); these reductions were offset by higher emissions of carbonyls. Formaldehyde, acetaldehyde, and butyraldehyde were the most significant carbonyls from the n-butanol blend, while formaldehyde, acetone, and 2-methylpropanal were the most significant from the i-butanol blend. The 12% i-butanol/7% ethanol blend was designed to produce no increase in gasoline vapor pressure. This fuel's exhaust emissions contained the lowest total oxygenates among the alcohol blends and the lowest NMOG of all fuels tested. PMID:24180630

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

    PubMed

    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. PMID:27019154

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

    PubMed

    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 < 0.05). Fish sauce inoculated with T. 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

  18. Fabrication, modeling and optimization of an ionic polymer gel actuator

    NASA Astrophysics Data System (ADS)

    Jo, Choonghee; Naguib, Hani E.; Kwon, Roy H.

    2011-04-01

    The modeling of the electro-active behavior of ionic polymer gel is studied and the optimum conditions that maximize the deflection of the gel are investigated. The bending deformation of polymer gel under an electric field is formulated by using chemo-electro-mechanical parameters. In the modeling, swelling and shrinking phenomena due to the differences in ion concentration at the boundary between the gel and solution are considered prior to the application of an electric field, and then bending actuation is applied. As the driving force of swelling, shrinking and bending deformation, differential osmotic pressure at the boundary of the gel and solution is considered. From this behavior, the strain or deflection of the gel is calculated. To find the optimum design parameter settings (electric voltage, thickness of gel, concentration of polyion in the gel, ion concentration in the solution, and degree of cross-linking in the gel) for bending deformation, a nonlinear constrained optimization model is formulated. In the optimization model, a bending deflection equation of the gel is used as an objective function, and a range of decision variables and their relationships are used as constraint equations. Also, actuation experiments are conducted using poly(2-acrylamido-2-methylpropane sulfonic acid) (PAMPS) gel and the optimum conditions predicted by the proposed model have been verified by the experiments.

  19. Mid-infrared surface transmitting and detecting quantum cascade device for gas-sensing

    NASA Astrophysics Data System (ADS)

    Harrer, Andreas; Szedlak, Rolf; Schwarz, Benedikt; Moser, Harald; Zederbauer, Tobias; Macfarland, Donald; Detz, Hermann; Andrews, Aaron Maxwell; Schrenk, Werner; Lendl, Bernhard; Strasser, Gottfried

    2016-02-01

    We present a bi-functional surface emitting and surface detecting mid-infrared device applicable for gas-sensing. A distributed feedback ring quantum cascade laser is monolithically integrated with a detector structured from a bi-functional material for same frequency lasing and detection. The emitted single mode radiation is collimated, back reflected by a flat mirror and detected by the detector element of the sensor. The surface operation mode combined with the low divergence emission of the ring quantum cascade laser enables for long analyte interaction regions spatially separated from the sample surface. The device enables for sensing of gaseous analytes which requires a relatively long interaction region. Our design is suitable for 2D array integration with multiple emission and detection frequencies. Proof of principle measurements with isobutane (2-methylpropane) and propane as gaseous analytes were conducted. Detectable concentration values of 0-70% for propane and 0-90% for isobutane were reached at a laser operation wavelength of 6.5 μm utilizing a 10 cm gas cell in double pass configuration.

  20. 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.

    PubMed

    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. PMID:25079080

  1. Antimicrobial efficacy of a novel silver hydrogel dressing compared to two common silver burn wound dressings: Acticoat™ and PolyMem Silver(®).

    PubMed

    Boonkaew, Benjawan; Kempf, Margit; Kimble, Roy; Supaphol, Pitt; Cuttle, Leila

    2014-02-01

    A novel burn wound hydrogel dressing has been previously developed which is composed of 2-acrylamido-2-methylpropane sulfonic acid sodium salt with silver nanoparticles. This study compared the antimicrobial efficacy of this novel dressing to two commercially available silver dressings; Acticoat™ and PolyMem Silver(®). Three different antimicrobial tests were used: disc diffusion, broth culture, and the Live/Dead(®) Baclight™ bacterial viability assay. Burn wound pathogens (P. aeruginosa, MSSA, A. baumannii and C. albicans) and antibiotic resistant strains (MRSA and VRE) were tested. All three antimicrobial tests indicated that Acticoat™ was the most effective antimicrobial agent, with inhibition zone lengths of 13.9-18.4mm. It reduced the microbial inocula below the limit of detection (10(2)CFU/ml) and reduced viability by 99% within 4h. PolyMem Silver(®) had no zone of inhibition for most tested micro-organisms, and it also showed poor antimicrobial activity in the broth culture and Live/Dead(®) Baclight™ assays. Alarmingly, it appeared to promote the growth of VRE. The silver hydrogel reduced most of the tested microbial inocula below the detection limit and decreased bacterial viability by 94-99% after 24h exposure. These results support the possibility of using this novel silver hydrogel as a burn wound dressing in the future. PMID:23790588

  2. Cytotoxicity testing of silver-containing burn treatments using primary and immortal skin cells.

    PubMed

    Boonkaew, Benjawan; Kempf, Margit; Kimble, Roy; Cuttle, Leila

    2014-12-01

    A novel burn wound hydrogel dressing has been previously developed which is composed of 2-acrylamido-2-methylpropane sulfonic acid sodium salt with silver nanoparticles (silver AMPS). This study compared the cytotoxicity of this dressing to the commercially available silver products; Acticoat™, PolyMem Silver(®) and Flamazine™ cream. Human keratinocytes (HaCaT and primary HEK) and normal human fibroblasts (NHF) were exposed to dressings incubated on Nunc™ polycarbonate inserts for 24, 48 and 72h. Four different cytotoxicity assays were performed including; Trypan Blue cell count, MTT, Celltiter-Blue™ and Toluidine Blue surface area assays. The results were expressed as relative cell viability compared to an untreated control. The cytotoxic effects of Acticoat™ and Flamazine™ cream were dependent on exposure time and cell type. After 24h exposure, Acticoat™ and Flamazine™ cream were toxic to all tested cell lines. Surprisingly, HaCaTs treated with Acticoat™ and Flamazine™ had an improved ability to survive at 48 and 72h while HEKs and NHFs had no improvement in survival with any treatment. The novel silver hydrogel and PolyMem Silver(®) showed low cytotoxicity to all tested cell lines at every time interval and these results support the possibility of using the novel silver hydrogel as a burn wound dressing. Researchers who rely on HaCaT cells as an accurate keratinocyte model should be aware that they can respond differently to primary skin cells. PMID:24767717

  3. Improved polymers for enhanced-oil-recovery synthesis and rheology. Fifth annual report, October 1981-September 1982

    SciTech Connect

    McCormick, C.L.; Hester, R.D.; Neidlinger, H.H.; Wildman, G.C.

    1983-10-01

    The goal of this project is to gain a more complete understanding of structure/property/performance interrelationships of water-soluble polymers which can aid industry in commercial production of polymers which are more efficient than those presently used. During the past the following have been accomplished: synthesis of model dextran-g-poly(acrylamide-co-sodium acrylates); synthesis of model dextran-g-poly(acrylamide-co-sodium-2-acrylamido-2-methylpropane sulfonates); characterization of model copolymers by elemental analysis, C-13NMR, and viscometry; study of dilute solution properties of the models including the effects of temperature, salt, pH; rheological studies of model graft copolymers; development of mathematical models, new calibration functions, analytical methods, and data acquisition techniques for aqueous size exclusion chromatography; application of quasielastic light scattering techniques to the study of hydrodynamic volume concepts; preferential and overall solvation studies of AN/NaA and AM/NaAMPS copolymers; study of phase behavior of model polymers in mono- and multivalent electrolytes at different polymer and salt concentrations as a function of temperature; education and training of students in basic energy research.

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

    NASA Astrophysics Data System (ADS)

    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.

  5. Fluid loss agents for oil well cementing composition

    SciTech Connect

    Savoly, A.; Villa, J.L.; Garvey, C.M.; Resnick, A.L.

    1987-06-23

    This patent describes a method of cementing a conduit in a borehole penetrating an earthen formation by introducing a cementing composition into the space. The cementing composition comprises: water; hydraulic cement; a water dispersible fluid loss additive comprised of a terpolymer of (1) from about 10 to about 75 weight percent of an acid selected from the group consisting of 2-acrylamido-2 methylpropane sulfonic acid, sodium vinyl sulfonate and vinyl benzene sulfonate; (2) from about 10 to 76 weight percent of a nonionic monomer selected from the group consisting of acrylamide, N,N-dimethylacrylamide, N-vinyl pyrrolidone, N-vinyl acetamide and dimethylamino ethyl methacrylate; and (3) from about 1 to 60 weight percent of an unsaturated polybasic acid selected from the group consisting of itaconic acid, maleic acid, fumaric acid, citraconic acid, mesaconic acid, glutaconic acid, aconitic acid, dimethylmuconic acid and 1-butene 2,3,4-tricarboxylic acid, the polymer having an average molecular weight of between about 200,000 and about 1,000,000 being in its free acid or partially or completely neutralized form and being at least water dispersible.

  6. γ-Unsaturated aldehydes as potential Lilial replacers.

    PubMed

    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

  7. Mid-infrared surface transmitting and detecting quantum cascade device for gas-sensing.

    PubMed

    Harrer, Andreas; Szedlak, Rolf; Schwarz, Benedikt; Moser, Harald; Zederbauer, Tobias; MacFarland, Donald; Detz, Hermann; Andrews, Aaron Maxwell; Schrenk, Werner; Lendl, Bernhard; Strasser, Gottfried

    2016-01-01

    We present a bi-functional surface emitting and surface detecting mid-infrared device applicable for gas-sensing. A distributed feedback ring quantum cascade laser is monolithically integrated with a detector structured from a bi-functional material for same frequency lasing and detection. The emitted single mode radiation is collimated, back reflected by a flat mirror and detected by the detector element of the sensor. The surface operation mode combined with the low divergence emission of the ring quantum cascade laser enables for long analyte interaction regions spatially separated from the sample surface. The device enables for sensing of gaseous analytes which requires a relatively long interaction region. Our design is suitable for 2D array integration with multiple emission and detection frequencies. Proof of principle measurements with isobutane (2-methylpropane) and propane as gaseous analytes were conducted. Detectable concentration values of 0-70% for propane and 0-90% for isobutane were reached at a laser operation wavelength of 6.5 μm utilizing a 10 cm gas cell in double pass configuration. PMID:26887891

  8. Quantitative analysis by GC-MS/MS of 18 aroma compounds related to oxidative off-flavor in wines.

    PubMed

    Mayr, Christine M; Capone, Dimitra L; Pardon, Kevin H; Black, Cory A; Pomeroy, Damian; Francis, I Leigh

    2015-04-01

    A quantitation method for 18 aroma compounds reported to contribute to "oxidative" flavor in wines was developed. The method allows quantitation of the (E)-2-alkenals ((E)-2-hexenal, (E)-2-heptenal, (E)-2-octenal, and (E)-2-nonenal), various Strecker aldehydes (methional, 2-phenylacetaldehyde, 3-methylbutanal, and 2-methylpropanal), aldehydes (furfural, 5-methylfurfural, hexanal, and benzaldehyde), furans (sotolon, furaneol, and homofuraneol), as well as alcohols (methionol, eugenol, and maltol) in the same analysis. The aldehydes were determined after derivatization directly in the wine with O-(2,3,4,5,6-pentafluorobenzyl)hydroxylamine hydrochloride; the formed oximes along with the underivatized aroma compounds were isolated by solid-phase extraction and analyzed by means of GC-MS/MS. The method was used to investigate the effect of different closures (synthetic closures, natural corks, and screw cap) on the formation of oxidation-related compounds in 14 year old white wine. Results showed a significant increase in the concentration of some of the monitored compounds in the wine, particularly methional, 2-phenylacetaldehyde, and 3-methylbutanal. PMID:25819472

  9. Structure-Activity Relationships in Human Toll-like Receptor 7-Active Imidazoquinoline Analogues

    PubMed Central

    Shukla, Nikunj M.; Malladi, Subbalakshmi S.; Mutz, Cole A.; Balakrishna, Rajalakshmi; David, Sunil A.

    2010-01-01

    Engagement of toll-like receptors serve to link innate immune responses with adaptive immunity and can be exploited as powerful vaccine adjuvants for eliciting both primary and anamnestic immune responses. TLR7 agonists are highly immunostimulatory without inducing dominant proinflammatory cytokine responses. A structure-activity study was conducted on the TLR7-agonistic imidazoquinolines, starting with 1-(4-amino-2-((ethylamino)methyl)-1H-imidazo[4,5-c]quinolin-1-yl)-2-methylpropan-2-ol as a lead. Modifications of the secondary amine of the C2 ethylaminomethylene sidechain are poorly tolerated. The 4-amino group must be retained for activity. Replacement of the imidazole ring of the scaffold with triazole or cyclic urea led to complete loss of activity. A systematic exploration of N1-benzyl-C2-alkyl substituents showed a very distinct relationship between alkyl length and TLR7-agonistic potency with the optimal compound bearing a C2-n-butyl group. Transposition of the N1 and C2 substituents led to the identification of an extremely active TLR7-agonistic compound with an EC50 value of 8.6 nM. The relative potencies in human TLR7-based primary reporter gene assays were paralleled by interferon-α induction activities in whole human blood models. PMID:20481492

  10. An unnatural death by propan-1-ol and propan-2-ol.

    PubMed

    Skopp, Gisela; Gutmann, Isabelle; Schwarz, Clara-Sophie; Schmitt, Georg

    2016-07-01

    A fatality of an inpatient ingesting a disinfectant containing ethanol, propan-1-ol, and propan-2-ol is reported. The alleged survival time was about 1 h. Major findings at autopsy were an extended hemorrhagic lung edema, an edematous brain, and shock kidneys. Concentrations of alcohols and acetone, a major metabolite of propan-2-ol, were determined from body fluids (blood from the heart and the femoral vein, urine, gastric contents) and tissues (brain, muscle, liver, kidneys, lungs) by headspace/gas chromatography using 2-methylpropan-2-ol as the internal standard. All samples investigated were positive for propan-1-ol, propan-2-ol, ethanol, and acetone except stomach contents, where acetone was not detectable. The low concentration of acetone compared to propan-2-ol likely supports the short survival time. The concentration ratios estimated from the results are in accordance with the physico-chemical properties of the particular alcohols, their different affinities towards alcohol dehydrogenase as well as their interdependence during biotransformation. Autopsy did not reveal the cause of death. According to the few published data, blood concentrations of 1.44 and 1.70 mg/g of propan-2-ol and propan-1-ol, respectively, are considered sufficient to have caused the death. This case also points to the need to restrict access to antiseptic solutions containing alcohols in wards with patients at risk. PMID:26712504

  11. Redox Potentials, Laccase Oxidation, and Antilarval Activities of Substituted Phenols

    PubMed Central

    Prasain, Keshar; Nguyen, Thi D. T.; Gorman, Maureen J.; Barrigan, Lydia M.; Peng, Zeyu; Kanost, Michael R.; Syed, Lateef U.; Li, Jun; Zhu, Kun Yan; Hua, Duy H.

    2012-01-01

    Laccases are copper-containing oxidases that are involved in sclerotization of the cuticle of mosquitoes and other insects. Oxidation of exogenous compounds by insect laccases may have the potential to produce reactive species toxic to insects. We investigated two classes of substituted phenolic compounds, halogenated di- and trihydroxybenzenes and substituted di-tert-butylphenols, on redox potential, oxidation by laccase and effects on mosquito larval growth. An inverse correlation between the oxidation potentials and laccase activity of halogenated hydroxybenzenes was found. Substituted di-tert-butylphenols however were found to impact mosquito larval growth and survival. In particular, 2,4-di-tert-butyl-6-(3-methyl-2-butenyl)phenol (15) caused greater than 98% mortality of Anopheles gambiae larvae in a concentration of 180 nM, whereas 2-(3,5-di-tert-butyl-4-hydroxyphenyl)-2-methylpropanal oxime (13) and 6,8-di-tert-butyl-2,2-dimethyl-3,4-dihydro-2H-chromene (33) caused 93% and 92% mortalities in concentrations of 3.4 and 3.7 μM, respectively. Larvae treated with di-tert-butylphenolic compounds died just before pupation. PMID:22300888

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

    SciTech Connect

    Wang, S.; Miller, D.L.; Cernansky, N.P.; Curran, H.J.; Pitz, W.J.; Westbrook, C.K.

    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.

  13. Comparison of Aroma-Active Volatiles in Oolong Tea Infusions Using GC-Olfactometry, GC-FPD, and GC-MS.

    PubMed

    Zhu, JianCai; Chen, Feng; Wang, LingYing; Niu, YunWei; Yu, Dan; Shu, Chang; Chen, HeXing; Wang, HongLin; Xiao, ZuoBing

    2015-09-01

    The aroma profile of oolong tea infusions (Dongdingwulong, DDWL; Tieguanyin, TGY; Dahongpao, DHP) were investigated in this study. Gas chromatography-olfactometry (GC-O) with the method of aroma intensity (AI) was employed to investigate the aroma-active compounds in tea infusions. The results presented forty-three, forty-five, and forty-eight aroma-active compounds in the TGY, DHP, and DDWL infusions, including six, seven, and five sulfur compounds, respectively. In addition, the concentration of volatile compounds in the tea infusions was further quantitated by solid phase microextraction-gas chromatography (SPME)-GC-MS and SPME-GC-flame photometric detection (FPD). Totally, seventy-six and thirteen volatile and sulfur compounds were detected in three types of tea infusions, respectively. Quantitative results showed that forty-seven aroma compounds were at concentrations higher than their corresponding odor thresholds. On the basis of the odor activity values (OAVs), 2-methylpropanal (OAV: 230-455), 3-methylbutanal (1-353), 2-methylbutanal (34-68), nerolidol (108-184), (E)-2-heptenal (148-294), hexanal (134-230), octanal (28-131), β-damascenone (29-59), indole (96-138), 6-methyl-5-hepten-2-one (34-67), (R)-(-)-linalool (63-87), and dimethyl sulfide (7-1320) presented relatively higher OAVs than those of other compounds, indicating the importance of these compounds in the overall aroma of tea infusions. PMID:26257073

  14. Synthesis and application of hybrid polymer composites based on silver nanoparticles as corrosion protection for line pipe steel.

    PubMed

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

    2014-01-01

    A facile method was developed to synthesize in high yield dispersed silver nanoparticles (AgNPs) with small particle sizes of less than 10 nm. Silver nitrate was reduced to silver nanoparticles by p-chloroaniline in the presence of polyoxyethylene maleate 4-nonyl-2-propylene-phenol (NMA) as a stabilizer. The produced AgNPs were used to prepare hybrid polymer based on N-isopropylacrylamide (NIPAm), 2-acrylamido-2-methylpropane sulfonic acid (AMPS), N,N-methylenebisacrylamide (MBA) and potassium persulfate (KPS) using a semi-batch solution polymerization method. The prepared AgNPs and hybrid polymer were characterized by Fourier transform infrared (FTIR) spectroscopy, X-ray diffraction (XRD) patterns and transmission electron microscopy (TEM). The corrosion inhibition activity of the AgNPs and hybrid polymer towards steel corrosion in the presence of hydrochloric acid has been investigated by polarization and electrochemical impedance spectroscopy (EIS) methods. Polarization measurements indicate that the AgNPs and hybrid polymer 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:24840897

  15. Mechanochemistry of ibuprofen pharmaceutical.

    PubMed

    Andini, Salvatore; Bolognese, Adele; Formisano, Domenico; Manfra, Michele; Montagnaro, Fabio; Santoro, Luciano

    2012-07-01

    In this paper mechanochemistry has been studied in view of possible application to detoxification of expired pharmaceuticals. The experiments have been carried out with a commercial medication containing ibuprofen ((RS)-2-(4-(2-methylpropyl)phenyl)propanoic acid) which has been submitted to prolonged milling up to 40h. When Al(OH)(3) is used as co-reagent, the first degradation step induced by the mechanochemical treatment is an acid-base reaction with the ibuprofen carboxylic acid group. The subsequent degradation follows a complex pathway leading to 1-(4-isobutylphenyl)ethanone, 1-isobutyl-4-vinylbenzene and 2-(4-(3-methylbutan-2-yl)phenyl)propan-1-ol after 10h milling and, in addition, 1-(4-acetylphenyl)-2-methylpropan-1-one, 1-(4-(1-hydroxy-2-methylpropyl)phenyl)ethanone and 1-(4-(2-hydroxy-2-methylpropyl)phenyl)ethanone after 40h milling. The degradation reaction path and products have been identified by means of FT-IR spectroscopy, thin layer chromatography, NMR spectroscopy, mass spectroscopy and elemental analysis. The observed ibuprofen decarboxylation makes the drug simultaneously lose both its pharmaceutical activity and toxicity. PMID:22472100

  16. Mid-infrared surface transmitting and detecting quantum cascade device for gas-sensing

    PubMed Central

    Harrer, Andreas; Szedlak, Rolf; Schwarz, Benedikt; Moser, Harald; Zederbauer, Tobias; MacFarland, Donald; Detz, Hermann; Andrews, Aaron Maxwell; Schrenk, Werner; Lendl, Bernhard; Strasser, Gottfried

    2016-01-01

    We present a bi-functional surface emitting and surface detecting mid-infrared device applicable for gas-sensing. A distributed feedback ring quantum cascade laser is monolithically integrated with a detector structured from a bi-functional material for same frequency lasing and detection. The emitted single mode radiation is collimated, back reflected by a flat mirror and detected by the detector element of the sensor. The surface operation mode combined with the low divergence emission of the ring quantum cascade laser enables for long analyte interaction regions spatially separated from the sample surface. The device enables for sensing of gaseous analytes which requires a relatively long interaction region. Our design is suitable for 2D array integration with multiple emission and detection frequencies. Proof of principle measurements with isobutane (2-methylpropane) and propane as gaseous analytes were conducted. Detectable concentration values of 0–70% for propane and 0–90% for isobutane were reached at a laser operation wavelength of 6.5 μm utilizing a 10 cm gas cell in double pass configuration. PMID:26887891

  17. Hypolipidemic and antioxidant activity of mountain celery (Cryptotaenia japonica Hassk) seed essential oils.

    PubMed

    Cheng, Ming-Ching; Lin, Li-Yun; Yu, Tung-Hsi; Peng, Robert Y

    2008-06-11

    Mountain celery seed essential oils (MC-E) contained 109 compounds, including mainly nine kinds of monoterpenoids, 31 kinds of of sesquiterpenoids, and 22 kinds of alcohols. A successive gel column adsorption with solvent fractionation yielded four fractionates. The pentane fractionate revealed potent hypolipidemic but poor antioxidant activities. The ether fractionate exhibited strong hypolipidemic activity in addition to excellent 1,1-diphenyl-2-picrylhydrazyl free radical- and superoxide anion-scavenging capabilities. The third acetone fractionate only showed moderate superoxide anion-scavenging activity. Finally, the fourth methanol fractionate having a rather high content of gamma-selinene, 2-methylpropanal, and Z-9-octadecenamide uniquely revealed very strong superoxide anion-scavenging capability. All MC diets except the MC-E-added diet simultaneously exhibited both significant hypolipidemic and high-density lipoprotein-cholesterol (HDL-C)-elevating capabilities. However, all diets totally failed to affect the hepatic phospholipid levels. Conclusively, the MC-E can be fractionated by such a separation technology to produce products uniquely possessing hypolipidemic and HDL-C-elevating activities. PMID:18473476

  18. Determination of direct photolysis rate constants and OH radical reactivity of representative odour compounds in brewery broth using a continuous flow-stirred photoreactor

    NASA Astrophysics Data System (ADS)

    Jürgens, Marion; Jacob, Fritz; Ekici, Perihan; Friess, Albrecht; Parlar, Harun

    A method based on photolysis was developed for the appropriate treatment of organic pollutants in air exhausting from breweries upon wort decoction, and thereby causing smell nuisance. A continuous flow stirred photoreactor was built-up exclusively, allowing OH radicals to react with selected odorous compounds contained in exhaust vapours, such as: 2-methylpropanal, 3-methylbutanal, 2-methylbutanal, 3-methyl-1-butanol, n-hexanal, 2-methylbutyl isobutyrate, 2-undecanone, phenyl acetaldehyde, myrcene, limonene, linalool, humulene, dimethylsulphide, and dimethyltrisulphide. These substances were quantified in brewery broth before and after UV irradiation using high-resolution gas chromatography-mass spectrometry (HRGC-MS). For odour analysis, high-resolution gas chromatography-flame ionisation detection (HRGC-FID) coupled with sensory methods was used. Determined quantum yields of about 10 -3 for phenyl acetaldehyde, myrcene, and humulene pointed out that direct photolysis contributed to their decay. Quantum yields of below 10 -4 for the other substances indicated that UV irradiation did not contribute significantly to their degradation processes. Hydroxyl radical reaction rate constants and Henry constants of organic compounds were also measured. Substances accompanied with low Henry constants converted rapidly, whereas those with higher ones, relatively slowly. Determined aroma values concluded that after UV-H 2O 2 treatment, only dimethylsulphide and myrcene remained as important odorous compounds, but in significantly reduced concentrations. The UV-H 2O 2 treatment of brewery broth has been proved effective to reduce smell-irritating substances formed upon wort decoction.

  19. Transferable force field for alcohols and polyalcohols.

    PubMed

    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

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

    NASA Astrophysics Data System (ADS)

    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. Determination of compounds responsible for tempeh aroma.

    PubMed

    Jeleń, Henryk; Majcher, Małgorzata; Ginja, Alexandra; Kuligowski, Maciej

    2013-11-01

    Tempeh is a fermented food, popular mainly in south-east Asia, but also among vegetarians worldwide. It is produced by fermenting soybean or other beans with Rhizopus strains and usually eaten deep-fried, steamed or roasted. The flavour of tempeh depends upon the fermentation time, beans used and the (eventual) frying process. Our goal was to identify compounds responsible for the unique aroma of fermented and fried soy tempeh. Gas chromatography-olfactometry (GC-O) with the aroma extract dilution analysis (AEDA) approach, was used to determine key odorants after 1 and 5 days of fermentation and subsequent frying. Comprehensive gas chromatography-mass spectrometry (GC×GC-ToF-MS) was used for their quantitation using stable isotope dilution analysis (SIDA) or standard addition (SA) methods. Odour activity values (OAV) were calculated for 19 out of 21 key odorants. Tempeh was fermented for 5 days and fried, and the main aroma compounds were found to be the following: 2-acetyl-1-pyrroline, (FD=1024, OAV 1380), 2-ethyl-3,5-dimethylpyrazine (FD=512, OAV 338), dimethyl trisulfide, (FD=512, OAV 900), methional (FD=512, OAV 930), 2-methylpropanal (FD=512, OAV 311) and (E,E)-2,4-decadienal (FD=512, OAV 455). The frying process induced the increase or appearance of the main key odorants in tempeh. PMID:23768380

  2. Selective determination of pharmaceuticals and illicit drugs in wastewaters using a novel strong cation-exchange solid-phase extraction combined with liquid chromatography-tandem mass spectrometry.

    PubMed

    Gilart, Núria; Cormack, P A G; Marcé, Rosa Maria; Fontanals, Núria; Borrull, Francesc

    2014-01-17

    In this study, two materials are presented with strong cation-exchange (SCX) behaviour synthesised by two different approaches and then crushed for their application as sorbents for solid-phase extraction (SPE) to extract a group of pharmaceuticals and illicit drugs selectively from wastewater samples. The first SCX polymer was obtained by copolymerisation of three monomers: 2-acrylamido-2-methylpropane sulphonic acid (AMPSA), 2-hydroxyethyl methacrylate (HEMA) and pentaerythritol triacrylate (PETRA), while the second was obtained by post-modification with sulphuric acid (H2SO4) of a copolymer based on HEMA and divinylbenzene (DVB). After their syntheses, both polymers were evaluated as SPE sorbents, with all parameters affecting SPE being optimised, such as sample pH, washing and elution solvents and volumes. Thanks to the sulphonic groups present in the structure of the polymers, all of the compounds with basic functionalities were retained on the sorbents after the washing step, removing the acidic analytes and other interfering compounds, providing successful results in terms of ion suppression/enhancement (-12% and 21%) when wastewater samples were analysed. However, AMPSA/HEMA/PETRA (20/60/20) failed to retain the analytes after loading wastewater samples (25 or 50mL), decreasing analyte recovery values significantly, whereas the sulphonated HEMA/DVB (50/50) enabled good SPE performance with recovery values between 70% and 98%, except for ranitidine and EDDP (39% and 43%, respectively). Therefore, this polymer was selected for further method validation and quantification of wastewater samples, providing low method detection limits (MDLs) in this matrix (from 2 to 40ngL(-1)). Finally, most of the studied compounds were detected and quantified in wastewater samples, especially atenolol, ranitidine, cocaine and its metabolite benzoylecgonine. PMID:24369996

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

    PubMed

    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 (P<0.05), and produced histamine in mGYP broth containing 5 and 25% NaCl in the level of 6.62-22.55 and 13.14-20.39 mg/100ml, respectively. Predominant volatile compounds of fish broth containing 25% NaCl inoculated with T. halophilus 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

  4. ESR characterization of a novel spin-trapping agent, 15N-labeled N-tert-butyl-alpha-phenylnitrone, as a nitric oxide donor.

    PubMed

    Saito, Kieko; Yoshioka, Hisashi

    2002-10-01

    We previously found that one of the pharmacological effects of N-tert-butyl-alpha-phenylnitrone (PBN) is the release of nitric oxide (NO) under oxidative conditions. However, to confirm this hypothesis in vivo, NO released from PBN must be distinguished from NO produced in biological systems, and therefore we undertook the synthesis of PBN using labeled 15N to identify its corresponding 15NO in vivo. The properties were examined with an ESR spectrometer. To synthesize 15N-PBN, the starting material, ammonium-15N chloride, was converted to 2-amino-15N-2-methylpropane, oxidized to 2-methyl-2-nitropropane-15N, and finally reacted with benzaldehyde to give 15N-PBN. The final product was purified by repeated sublimation. With ferrous sulfate-methyl glucamine dithiocarbamate complex, Fe (MGD)2, as a trapping agent to measure the NO levels of 15N-PBN or 14N-PBN in vitro, the peak intensity of 15NO[Fe(MGD)2] was over 50% stronger than that of 14NO[Fe(MGD)2], and that 15NO and 14NO had the corresponding two-and three line hyperfine structures due to their nuclear spin quantum numbers. Subsequently, the ESR spectrum of 15NO derived from 15N-PBN was significantly different than that of lipopolysaccharide (LPS)-induced NO, which was derived from biological cells, and therefore we have demonstrated the possibility to distinguish 15NO from PBN and 14NO generated from cells. These results suggested that 15N-PBN is a useful molecule, not only as a spin-trapping agent, but also as an NO donor to explore the pharmacological mechanisms of PBN in vivo. PMID:12450131

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

    PubMed

    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

  6. Recovery of anhydrous Na{sub 2}SO{sub 4} from SO{sub 2}-scrubbing liquor by extractive crystallization: Liquid-liquid equilibria for aqueous solutions of sodium carbonate, sulfate, and/or sulfite plus acetone, 2-propanol, or tert-butyl alcohol

    SciTech Connect

    Lynn, S.; Cos, R.; Prausnitz, J.M.; Schiozer, A.L.; Jaecksch, W.L.

    1996-11-01

    Sodium carbonate is a superior scrubbing agent for removing SO{sub 2} from combustion gases, but the resulting sodium sulfate (or sulfite) must be recovered for environmental reasons. Recovery by evaporative crystallization is energy-intensive; extractive crystallization provides an attractive alterative when technically feasible. Liquid/liquid equilibrium data were determined for two-phase mixtures containing aqueous solutions of sodium carbonate, sulfate, or sulfite and a polar organic solvent: acetone, 2-propanol, and 2-methylpropan-1-ol (i.e., tert-butyl alcohol). In the salt-saturated two-phase region, data were obtained between the lower consolute temperature and 60 C (50 C for acetone). data were also obtained at 35 C for liquid/liquid systems that were subsaturated with their respective salts and for liquid/liquid systems with overall molar ratios of sodium sulfite/sodium sulfate fixed at 25/75, 50/50, and 75/25. In the latter systems, it was found that the sulfite/sulfate ratios in the organic and aqueous phases were the same, i.e., there is no selectivity by these solvents for one salt relative to the other. The data show that any one of these solvents can be used to extract water from a concentrated solution of either sodium sulfite or sodium sulfate in a countercurrent extractor at 35 C, causing the anhydrous salt to crystallize. The wet solvent can be dried for recycle in a similar countercurrent operation at 35 C, using a saturated solution of Na{sub 2}CO{sub 3} as the drying agent. The number of moles of carbonate required for drying does not exceed the number of moles of sulfite-plus-sulfate precipitated. The process energy is about 0% of that required for single-stage evaporative crystallization of the same liquor.

  7. Improving the efficiency of configurational-bias Monte Carlo: A density-guided method for generating bending angle trials for linear and branched molecules

    SciTech Connect

    Sepehri, Aliasghar; Loeffler, Troy D.; Chen, Bin

    2014-08-21

    A new method has been developed to generate bending angle trials to improve the acceptance rate and the speed of configurational-bias Monte Carlo. Whereas traditionally the trial geometries are generated from a uniform distribution, in this method we attempt to use the exact probability density function so that each geometry generated is likely to be accepted. In actual practice, due to the complexity of this probability density function, a numerical representation of this distribution function would be required. This numerical table can be generated a priori from the distribution function. This method has been tested on a united-atom model of alkanes including propane, 2-methylpropane, and 2,2-dimethylpropane, that are good representatives of both linear and branched molecules. It has been shown from these test cases that reasonable approximations can be made especially for the highly branched molecules to reduce drastically the dimensionality and correspondingly the amount of the tabulated data that is needed to be stored. Despite these approximations, the dependencies between the various geometrical variables can be still well considered, as evident from a nearly perfect acceptance rate achieved. For all cases, the bending angles were shown to be sampled correctly by this method with an acceptance rate of at least 96% for 2,2-dimethylpropane to more than 99% for propane. Since only one trial is required to be generated for each bending angle (instead of thousands of trials required by the conventional algorithm), this method can dramatically reduce the simulation time. The profiling results of our Monte Carlo simulation code show that trial generation, which used to be the most time consuming process, is no longer the time dominating component of the simulation.

  8. Improving the efficiency of configurational-bias Monte Carlo: A density-guided method for generating bending angle trials for linear and branched molecules

    NASA Astrophysics Data System (ADS)

    Sepehri, Aliasghar; Loeffler, Troy D.; Chen, Bin

    2014-08-01

    A new method has been developed to generate bending angle trials to improve the acceptance rate and the speed of configurational-bias Monte Carlo. Whereas traditionally the trial geometries are generated from a uniform distribution, in this method we attempt to use the exact probability density function so that each geometry generated is likely to be accepted. In actual practice, due to the complexity of this probability density function, a numerical representation of this distribution function would be required. This numerical table can be generated a priori from the distribution function. This method has been tested on a united-atom model of alkanes including propane, 2-methylpropane, and 2,2-dimethylpropane, that are good representatives of both linear and branched molecules. It has been shown from these test cases that reasonable approximations can be made especially for the highly branched molecules to reduce drastically the dimensionality and correspondingly the amount of the tabulated data that is needed to be stored. Despite these approximations, the dependencies between the various geometrical variables can be still well considered, as evident from a nearly perfect acceptance rate achieved. For all cases, the bending angles were shown to be sampled correctly by this method with an acceptance rate of at least 96% for 2,2-dimethylpropane to more than 99% for propane. Since only one trial is required to be generated for each bending angle (instead of thousands of trials required by the conventional algorithm), this method can dramatically reduce the simulation time. The profiling results of our Monte Carlo simulation code show that trial generation, which used to be the most time consuming process, is no longer the time dominating component of the simulation.

  9. Excited singlet molecular O2 (1Δg) is generated enzymatically from excited carbonyls in the dark

    PubMed Central

    Mano, Camila M.; Prado, Fernanda M.; Massari, Júlio; Ronsein, Graziella E.; Martinez, Glaucia R.; Miyamoto, Sayuri; Cadet, Jean; Sies, Helmut; Medeiros, Marisa H. G.; Bechara, Etelvino J. H.; Di Mascio, Paolo

    2014-01-01

    In mammalian tissues, ultraweak chemiluminescence arising from biomolecule oxidation has been attributed to the radiative deactivation of singlet molecular oxygen [O2 (1Δg)] and electronically excited triplet carbonyl products involving dioxetane intermediates. Herein, we describe evidence of the generation of O2 (1Δg) in aqueous solution via energy transfer from excited triplet acetone. This involves thermolysis of 3,3,4,4-tetramethyl-1,2-dioxetane, a chemical source, and horseradish peroxidase-catalyzed oxidation of 2-methylpropanal, as an enzymatic source. Both sources of excited carbonyls showed characteristic light emission at 1,270 nm, directly indicative of the monomolecular decay of O2 (1Δg). Indirect analysis of O2 (1Δg) by electron paramagnetic resonance using the chemical trap 2,2,6,6-tetramethylpiperidine showed the formation of 2,2,6,6-tetramethylpiperidine-1-oxyl. Using [18O]-labeled triplet, ground state molecular oxygen [18O2 (3Σg-)], chemical trapping of 18O2 (1Δg) with disodium salt of anthracene-9,10-diyldiethane-2,1-diyl disulfate yielding the corresponding double-[18O]-labeled 9,10-endoperoxide, was detected through mass spectrometry. This corroborates formation of O2 (1Δg). Altogether, photoemission and chemical trapping studies clearly demonstrate that chemically and enzymatically nascent excited carbonyl generates 18O2 (1Δg) by triplet-triplet energy transfer to ground state oxygen O2 (3Σg−), and supports the long formulated hypothesis of O2 (1Δg) involvement in physiological and pathophysiological events that might take place in tissues in the absence of light. PMID:25087485

  10. Bacterial Degradation of tert-Amyl Alcohol Proceeds via Hemiterpene 2-Methyl-3-Buten-2-ol by Employing the Tertiary Alcohol Desaturase Function of the Rieske Nonheme Mononuclear Iron Oxygenase MdpJ

    PubMed Central

    Schuster, Judith; Schäfer, Franziska; Hübler, Nora; Brandt, Anne; Rosell, Mònica; Härtig, Claus; Harms, Hauke; Müller, Roland H.

    2012-01-01

    Tertiary alcohols, such as tert-butyl alcohol (TBA) and tert-amyl alcohol (TAA) and higher homologues, are only slowly degraded microbially. The conversion of TBA seems to proceed via hydroxylation to 2-methylpropan-1,2-diol, which is further oxidized to 2-hydroxyisobutyric acid. By analogy, a branched pathway is expected for the degradation of TAA, as this molecule possesses several potential hydroxylation sites. In Aquincola tertiaricarbonis L108 and Methylibium petroleiphilum PM1, a likely candidate catalyst for hydroxylations is the putative tertiary alcohol monooxygenase MdpJ. However, by comparing metabolite accumulations in wild-type strains of L108 and PM1 and in two mdpJ knockout mutants of strain L108, we could clearly show that MdpJ is not hydroxylating TAA to diols but functions as a desaturase, resulting in the formation of the hemiterpene 2-methyl-3-buten-2-ol. The latter is further processed via the hemiterpenes prenol, prenal, and 3-methylcrotonic acid. Likewise, 3-methyl-3-pentanol is degraded via 3-methyl-1-penten-3-ol. Wild-type strain L108 and mdpJ knockout mutants formed isoamylene and isoprene from TAA and 2-methyl-3-buten-2-ol, respectively. It is likely that this dehydratase activity is catalyzed by a not-yet-characterized enzyme postulated for the isomerization of 2-methyl-3-buten-2-ol and prenol. The vitamin requirements of strain L108 growing on TAA and the occurrence of 3-methylcrotonic acid as a metabolite indicate that TAA and hemiterpene degradation are linked with the catabolic route of the amino acid leucine, including an involvement of the biotin-dependent 3-methylcrotonyl coenzyme A (3-methylcrotonyl-CoA) carboxylase LiuBD. Evolutionary aspects of favored desaturase versus hydroxylation pathways for TAA conversion and the possible role of MdpJ in the degradation of higher tertiary alcohols are discussed. PMID:22194447

  11. On-road emission characteristics of VOCs from rural vehicles and their ozone formation potential in Beijing, China

    NASA Astrophysics Data System (ADS)

    Yao, Zhiliang; Wu, Bobo; Shen, Xianbao; Cao, Xinyue; Jiang, Xi; Ye, Yu; He, Kebin

    2015-03-01

    This paper is the second in a series of papers aimed at understanding volatile organic compound (VOC) emissions from motor vehicles in Beijing using on-board emission measurements, focusing specifically on rural vehicles (RVs). In this work, 13 RVs, including 6 different 3-wheel (3-W) RVs and 7 different 4-wheel (4-W) RVs, were examined using a portable emissions measurement system (PEMS) as the vehicles were driven on predesigned fixed test routes in rural areas of Beijing. Overall, 50 VOC species were quantified in this study, including 18 alkanes, 5 alkenes, 11 aromatics, 13 carbonyls and 3 other compounds. The average emission factor (EF) of the total VOCs for the 4-W RVs based on the distance traveled was 326.2 ± 129.3 mg/km, which is 2.5 times greater than that of the 3-W RVs. However, the VOC emissions for the 3-W RVs had higher EFs based on their CO2 emissions due to the different fuel economies of the two types of RVs. Formaldehyde, toluene, acetaldehyde, m-xylene, p-xylene, isopentane, benzene, ethylbenzene, n-pentane, 2-methoxy-2-methylpropane and butenal were the dominant VOC species from the RVs, accounting for an average of 68.6% of the total VOC emissions. Overall, the RVs had high proportions of aromatics and carbonyls. The ozone formation potentials (OFPs) were 670.6 ± 227.2 and 1454.1 ± 643.0 mg O3/km for the 3-W and 4-W RVs, respectively, and approximately 60%-70% of the OFP resulted from carbonyls. We estimated that the 3-W and 4-W RVs accounted for approximately 50% and 10%, respectively, of the total OFP caused by diesel vehicles (including diesel trucks and RVs) in Beijing in 2012. Thus, more attention should be given to VOC emissions and their impact on ozone formation.

  12. Solution properties of water soluble macromolecules for enhanced oil recovery applications

    SciTech Connect

    Lindner, J.S.

    1985-01-01

    Static and dynamic light scattering, dilute solution viscometry and membrane osmometry were used to determine the solution properties of two different series of copolymers. A series of dextran polysaccharides and poly(acrylamides) differing in molar mass were evaluated. Dextrans were observed to obey the relationships Dz = 8.45 x 10/sup -5/ M/sup x/ and eta = 0.366 M/sup y/ where x = -0.5, y = 0.39, Dz is the translational z-average diffusion coefficient, eta the intrinsic viscosity, and M the molecular weight. The exponents of both power laws indicate that dextrans were branched polymers and that water was a marginal solvent. Poly(acrylamides) were described by Dz = 1.25 x 10/sup -4/ M/sup x/ and eta = 6.36 x 10/sup -3/ M/sup y/ where x = -0.54 and y = 0.79. The exponents indicated that poly(acrylamides) exhibit extensive excluded volumes and extended configurations in water. Dextran-g-acrylamide copolymers with small numbers of branches tended to associate while samples with high branching densities exhibited polyelectrolyte behavior. Addition of 0.1 N KCl to aqueous solutions of the graft copolymers resulted in normal solution behavior. Associates species were disrupted by the action of the salt on hydrogen bonds. Unshielded ionizable groups were neutralized. Derived solution parameters did not depend on previously reported structural characteristics. In brine, linear copolymers of acrylamide with Na-2-acryamido-2 methylpropane/sulfonate (AMPS) exhibited large excluded volumes. Consideration of the solution properties of the two different copolymer series indicated that linear copolymers of acrylamide with AMPS may be useful in enhanced oil recovery application. Dextran-g-acrylamide copolymers offer no distinct advantages.

  13. Photooxidation of 2-methyl-3-Buten-2-ol (MBO) as a potential source of secondary organic aerosol.

    PubMed

    Chan, Arthur W H; Galloway, Melissa M; Kwan, Alan J; Chhabra, Puneet S; Keutsch, Frank N; Wennberg, Paul O; Flagan, Richard C; Seinfeld, John H

    2009-07-01

    2-Methyl-3-buten-2-ol (MBO) is an important biogenic hydrocarbon emitted in large quantities by pine forests. Atmospheric photooxidation of MBO is known to lead to oxygenated compounds, such as glycolaldehyde, which is the precursor to glyoxal. Recent studies have shown that the reactive uptake of glyoxal onto aqueous particles can lead to formation of secondary organic aerosol (SOA). In this work, MBO photooxidation under high- and low-NO(x) conditions was performed in dual laboratory chambers to quantify the yield of glyoxal and investigate the potential for SOA formation. The yields of glycolaldehyde and 2-hydroxy-2-methylpropanal (HMPR), fragmentation products of MBO photooxidation, were observed to be lower at lower NO(x) concentrations. Overall, the glyoxal yield from MBO photooxidation was 25% under high-NO(x) and 4% under low-NO(x) conditions. In the presence of wet ammonium sulfate seed and under high-NO(x) conditions, glyoxal uptake and SOA formation were not observed conclusively, due to relatively low (< 30 ppb) glyoxal concentrations. Slight aerosol formation was observed under low-NO(x) and dry conditions, with aerosol mass yields on the order of 0.1%. The small amount of SOA was not related to glyoxal uptake, but is likely a result of reactions similar to those that generate isoprene SOA under low-NO(x) conditions. The difference in aerosol yields between MBO and isoprene photooxidation under low-NO(x) conditions is consistent with the difference in vapor pressures between triols (from MBO) and tetrols (from isoprene). Despite its structural similarity to isoprene, photooxidation of MBO is not expected to make a significant contribution to SOA formation. PMID:19673246

  14. TAME5OX, abiotic siderophore analogue to enterobactin involving 8-hydroxyquinoline subunits: thermodynamic and photophysical studies.

    PubMed

    Akbar, Rifat; Baral, Minati; Kanungo, B K

    2015-05-01

    The synthesis, thermodynamic and photophysical properties of trivalent metal complexes of biomimetic nonadentate analogue, 5,5'-(2-(((8-hydroxyquinolin-5-yl)methylamino)methyl)-2-methylpropane-1,3-diyl)bis(azanediyl)bis(methylene)diquinolin-8-ol (TAME5OX), have been described. Combination of absorption and emission spectrophotometry, potentiometry, electrospray mass spectrometry, IR, and theoretical investigation were used to fully characterize metal (Fe(+3), Al(+3) and Cr(+3)) chelates of TAME5OX. In solution, TAME5OX forms protonated complexes [M(H3L)](3+) below pH 3.4, which consecutively deprotonates through one to three-proton processes with rise of pH. The formation constants (Logβ11n) of neutral complexes formed at or above physiological pH, have been determined to be 30.18, 23.27 and 22.02 with pM values of 31.16, 18.07 and 18.12 for Fe(+3), Al(+3) and Cr(+3) ions, respectively, calculated at pH 7.4, indicating TAME5OX is a powerful among synthetic metal chelator. The results clearly demonstrate that the ligand in a tripodal orchestration firmly binds these ions over wide pH range and forms distorted octahedral complexes. The binding and the coordination event could be monitored from absorption and fluorescence spectroscopy. The high thermodynamic stability in water at physiological pH of ferric complex of TAME5OX indicates that these complexes are resistant to hydrolysis and therefore are well suited for the development of device for applications as probes. The ligand displays high sensitive fluorescence enhancement to Al(3+) at pH 7.4, in water. Moreover, TAME5OX can distinguish Al(3+) from Fe(3+) and Cr(3+) via two different sensing mechanisms: photoinduced electron transfer (PET) for Al(3+) and internal charge transfer (ICT) for Fe(3+) and Cr(3+). Density functional theory was employed for optimization and evaluation of vibrational modes, NBO analysis, excitation and emission properties of the different species of metal complexes observed by solution

  15. TAME5OX, abiotic siderophore analogue to enterobactin involving 8-hydroxyquinoline subunits: Thermodynamic and photophysical studies

    NASA Astrophysics Data System (ADS)

    Akbar, Rifat; Baral, Minati; Kanungo, B. K.

    2015-05-01

    The synthesis, thermodynamic and photophysical properties of trivalent metal complexes of biomimetic nonadentate analogue, 5,5‧-(2-(((8-hydroxyquinolin-5-yl)methylamino)methyl)-2-methylpropane-1,3-diyl)bis(azanediyl)bis(methylene)diquinolin-8-ol (TAME5OX), have been described. Combination of absorption and emission spectrophotometry, potentiometry, electrospray mass spectrometry, IR, and theoretical investigation were used to fully characterize metal (Fe+3, Al+3 and Cr+3) chelates of TAME5OX. In solution, TAME5OX forms protonated complexes [M(H3L)]3+ below pH 3.4, which consecutively deprotonates through one to three-proton processes with rise of pH. The formation constants (Log β11n) of neutral complexes formed at or above physiological pH, have been determined to be 30.18, 23.27 and 22.02 with pM values of 31.16, 18.07 and 18.12 for Fe+3, Al+3 and Cr+3 ions, respectively, calculated at pH 7.4, indicating TAME5OX is a powerful among synthetic metal chelator. The results clearly demonstrate that the ligand in a tripodal orchestration firmly binds these ions over wide pH range and forms distorted octahedral complexes. The binding and the coordination event could be monitored from absorption and fluorescence spectroscopy. The high thermodynamic stability in water at physiological pH of ferric complex of TAME5OX indicates that these complexes are resistant to hydrolysis and therefore are well suited for the development of device for applications as probes. The ligand displays high sensitive fluorescence enhancement to Al3+ at pH 7.4, in water. Moreover, TAME5OX can distinguish Al3+ from Fe3+ and Cr3+ via two different sensing mechanisms: photoinduced electron transfer (PET) for Al3+ and internal charge transfer (ICT) for Fe3+ and Cr3+. Density functional theory was employed for optimization and evaluation of vibrational modes, NBO analysis, excitation and emission properties of the different species of metal complexes observed by solution studies.

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

    NASA Astrophysics Data System (ADS)

    Kaser, L.; Karl, T.; Schnitzhofer, R.; Graus, M.; Herdlinger-Blatt, I. S.; DiGangi, J. P.; Sive, B.; Turnipseed, A.; Hornbrook, R. S.; Zheng, W.; Flocke, F. M.; Guenther, A.; Keutsch, F. N.; Apel, E.; Hansel, A.

    2012-10-01

    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, and likely

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

    NASA Astrophysics Data System (ADS)

    Kaser, L.; Karl, T.; Schnitzhofer, R.; Graus, M.; Herdlinger-Blatt, I. S.; DiGangi, J. P.; Sive, B.; Turnipseed, A.; Hornbrook, R. S.; Zheng, W.; Flocke, F. M.; Guenther, A.; Keutsch, F. N.; Apel, E.; Hansel, A.

    2013-03-01

    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, and

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

    PubMed

    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

  19. Light-scattering study of polyelectrolyte complex formation between anionic and cationic nanogels in an aqueous salt-free system.

    PubMed

    Miyake, Masafumi; Ogawa, Kazuyoshi; Kokufuta, Etsuo

    2006-08-15

    We studied complex formation in an aqueous salt-free system (pH approximately 3 and at 25 degrees C) between nanogel particles having opposite charges. Anionic gel (AG) and cationic gel (CG) particles consist of lightly cross-linked N-isopropylacrylamide (NIPA) copolymers with 2-acrylamido-2-methylpropane sulfonic acid and with 1-vinylimidazole, respectively. The number of charges per particle was -4490 for AG and +20 300 for CG, as estimated from their molar masses (3.33 MD for AG and 11.7 MD for CG) by static light scattering (SLS) and their charge densities (1.35 mmol/g for AG and 1.74 mmol/g for CG) by potentiometric titration. The complexes were formed through the addition of AG to CG and vice versa using a turbidimetric titration technique. At the endpoint of the titration, the aggregate formed was a complex based upon stoichiometric charge neutralization: CG(n)()(+) + xAG(m)()(-) --> CG(n)()(+) (AG(m)()(-))(x)() where x = (n)()/(m)(). At different stages of the titration before the endpoint, the resulting complexes were examined in detail using dynamic light scattering, SLS, and electrophoretic light scattering (ELS). The main results are summarized as follows: (i) When AG with a hydrodynamic radius (R(h)) of 119 nm is added to CG (R(h) approximately 156 nm), the (R(h)) of the complex size decreases from 156 to 80 nm. (ii) In contrast to this (R(h)) change, the molar mass increases from 11.7 MD to 24 MD with increasing amounts of added AG. (iii) Upon addition of CG to AG, the complex formed has the same size ((R(h)) approximately 80 nm) and the same molar mass (55 +/- 2.5 MD) until 55 +/- 5% of AG has been consumed in the complexation. To understand these results, we used the following two models: the random model (RM), in which the added AG particles uniformly bind to all of the CG particles in the system via a strong electrostatic attraction, and the all-or-none model (AONM), in which part of the AG particles in the system preferably bind to the added CG

  20. Optimisation and validation of a HS-SPME-GC-IT/MS method for analysis of carbonyl volatile compounds as biomarkers in human urine: Application in a pilot study to discriminate individuals with smoking habits.

    PubMed

    Calejo, Isabel; Moreira, Nathalie; Araújo, Ana Margarida; Carvalho, Márcia; Bastos, Maria de Lourdes; de Pinho, Paula Guedes

    2016-02-01

    A new and simple analytical approach consisting of an automated headspace solid-phase microextraction (HS-SPME) sampler coupled to gas chromatography-ion trap/mass spectrometry detection (GC-IT/MS) with a prior derivatization step with O-(2,3,4,5,6-pentafluorobenzyl)hydroxylamine hydrochloride (PFBHA) was developed to detect volatile carbonyl metabolites with low molecular weights in human urine. A central composite design (CCD) was used to optimise the PFBHA concentration and extraction conditions that affect the efficiency of the SPME procedure. With a sample volume of 1 mL, optimal conditions were achieved by adding 300 mg/L of PFBHA and allowing the sample to equilibrate for 6 min at 62°C and then extracting the samples for 51 min at the same temperature, using a divinylbenzene/polydimethylsiloxane (DVB/PDMS) fibre. The method allowed the simultaneous identification and quantification of 44 carbonyl compounds consisting of aldehydes, dialdehydes, heterocyclic aldehydes and ketones. The method was validated with regards to the linearity, inter- and intra-day precision and accuracy. The detection limits ranged from 0.009 to 0.942 ng/mL, except for 4-hydroxy-2-nonenal (15 ng/mL), and the quantification limits varied from 0.029 to 1.66 ng/mL, except for butanal (2.78 ng/mL), 2-butanone (2.67 ng/mL), 4-heptanone (3.14 ng/mL) and 4-hydroxy-2-nonenal (50.0 ng/mL). The method accuracy was satisfactory, with recoveries ranging from 90 to 107%. The proof of applicability of the methodology was performed in a pilot target analysis of urine samples obtained from 18 healthy smokers and 18 healthy non-smokers (control group). Chemometric supervised analysis was performed using the volatile patterns acquired for these samples and clearly showed the potential of the volatile carbonyl profiles to discriminate urine from smoker and non-smoker subjects. 5-Methyl-2-furfural (p<0.0001), 2-methylpropanal, nonanal and 2-methylbutanal (p<0.05) were identified as potentially useful

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

    PubMed

    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

  2. Singlet molecular oxygen generated in dark biological process.

    PubMed

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

    PubMed

    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. PMID:26066097

  4. Metabolism and Disposition of Hepatitis C Polymerase Inhibitor Dasabuvir in Humans.

    PubMed

    Shen, Jianwei; Serby, Michael; Reed, Aimee; Lee, Anthony J; Menon, Rajeev; Zhang, Xiaomei; Marsh, Kennan; Wan, Xia; Kavetskaia, Olga; Fischer, Volker

    2016-08-01

    Dasabuvir [also known as ABT-333 or N-(6-(3-(tert-butyl)-5-(2,4-dioxo-3,4-dihydropyrimidin-1(2H)-yl)-2-methoxyphenyl)naphthalen-2-yl)methanesulfonamide] is a potent non-nucleoside NS protein 5B polymerase inhibitor of the hepatitis C virus (HCV) and is being developed in combination with paritaprevir/ritonavir and ombitasvir in an oral regimen with three direct-acting antivirals for the treatment of patients infected with HCV genotype 1. This article describes the mass balance, metabolism, and disposition of dasabuvir in humans. After administration of a single oral dose of 400-mg [(14)C]dasabuvir (without coadministration of paritaprevir/ritonavir and ombitasvir) to four healthy male volunteers, the mean total percentage of the administered radioactive dose recovered was 96.6%. The recovery from the individual subjects ranged from 90.8% to 103%. Dasabuvir and corresponding metabolites were predominantly eliminated in feces (94.4% of the dose) and minimally through renal excretion (2.2% of the dose). The biotransformation of dasabuvir primarily involves hydroxylation of the tert-butyl group to form active metabolite M1 [N-(6-(5-(2,4-dioxo-3,4-dihydropyrimidin-1(2H)-yl)-3-(1-hydroxy-2-methylpropan-2-yl)-2-methoxyphenyl)naphthalen-2-yl)methanesulfonamide], followed by glucuronidation and sulfation of M1 and subsequent secondary oxidation. Dasabuvir was the major circulating component (58% of total radioactivity) in plasma, followed by metabolite M1 (21%). Other minor metabolites represented < 10% each of total circulating radioactivity. Dasabuvir was cleared mainly through cytochrome P450-mediated oxidation metabolism to M1. M1 and its glucuronide and sulfate conjugates were primarily eliminated in feces. Subsequent oxidation of M1 to the tert-butyl acid, followed by formation of the corresponding glucuronide conjugate, plays a secondary role in elimination. Cytochrome P450 profiling indicated that dasabuvir was mainly metabolized by CYP2C8, followed by CYP3A4. In

  5. Analysis of phosphate esters in plant material

    PubMed Central

    Isherwood, F. A.; Barrett, F. C.

    1967-01-01

    1. A critical study was made of the quantitative extraction of nucleotide and sugar phosphates from plant tissue by either boiling aqueous ethanol or cold trichloroacetic acid. The effect of the extraction technique on the inactivation of the enzymes in the plant tissue and the possibility of adsorption of the phosphate esters on the cell wall were especially considered. 2. In the recommended method the plant tissue was frozen in liquid nitrogen, ground to a powder and then blended with cold aqueous trichloroacetic acid containing 8-hydroxyquinoline to prevent adsorption. 3. The extract contained large amounts of trichloroacetic acid, cations, chloride, sugars, amino acids, hydroxy organic acids, phytic acid, orthophosphoric acid and high-molecular-weight material including some phosphorus-containing compounds. All of these were removed as they were liable to interfere with the chromatographic or enzymic assay of the individual nucleotide or sugar phosphates. 4. The procedure was as follows: the last traces of trichloroacetic acid were extracted with ether after the solution had been passed through a column of Dowex AG 50 in the hydrogen form to remove all cations. High-molecular-weight compounds were removed by ultrafiltration and low-molecular-weight solutes by a two-stage chromatography on cellulose columns with organic solvents. In the first stage, sugars, amino acids, chloride and phytic acid were separated by using a basic solvent (propan-1-ol–water–aqueous ammonia) and, in the second stage, the organic acids and orthophosphoric acid were separated by using an acidic solvent (di-isopropyl ether–formic acid–2-methylpropan-2-ol–water). The final solution of nucleotide and sugar phosphates was substantially free from other solutes and was suitable for the detection of individual phosphate esters by either chromatography or enzymic assay. 5. The recovery of d-glucose 6-phosphate or adenosine 5′-triphosphate added to a trichloroacetic acid extract

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

    PubMed Central

    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

  7. A Unique Equation to Estimate Flash Points of Selected Pure Liquids Application to the Correction of Probably Erroneous Flash Point Values

    NASA Astrophysics Data System (ADS)

    Catoire, Laurent; Naudet, Valérie

    2004-12-01

    several flash points have been reported erroneously, whatever the reason, in one or several reference compilations. In the following lists, the currently accepted flash points for bold compounds err, or probably err, on the hazardous side by at least 10 °C and for the nonbolded compounds, the currently accepted flash points err, or probably err, on the nonhazardous side by at least 10 °C: bicyclohexyl, sec-butylamine, tert-butylamine, 2-cyclohexen-1-one, ethanethiol, 1,3-cyclohexadiene, 1,4-pentadiene, methyl formate, acetonitrile, cinnamaldehyde, 1-pentanol, diethylene glycol, diethyl fumarate, diethyl phthalate, trimethylamine, dimethylamine, 1,6-hexanediol, propylamine, methanethiol, ethylamine, bromoethane, 1-bromopropane, tert-butylbenzene, 1-chloro-2-methylpropane, diacetone alcohol, diethanolamine, 2-ethylbutanal, and formic acid. For some other compounds, no other data than the currently accepted flash points are available. Therefore, it cannot be assessed that these flash point data are erroneous but it can be stated that they are probably erroneous. At least, they need experimental re-examination. They are probably erroneous by at least 15 °C: 1,3-cyclopentadiene, di-tert-butyl sulfide, dimethyl ether, dipropyl ether, 4-heptanone, bis(2-chloroethyl)ether, 1-decanol, 1-phenyl-1-butanone, furan, ethylcyclopentane, 1-heptanethiol, 2,5-hexanediol, 3-hexanone, hexanoic acid methyl ester, 4-methyl-1,3-pentadiene, propanoyl chloride, tetramethylsilane, thiacyclopentane, 1-chloro-2-methyl-1-propene, trans-1,3-pentadiene, 2,3-dimethylheptane, triethylenetetramine, methylal, N-ethylisopropylamine, 3-methyl-2-pentene, and 2,3-dimethyl-1-butene.