WorldWideScience

Sample records for ethylene oxide oligomers

  1. Diffusivities and Viscosities of Poly(ethylene oxide) Oligomers

    KAUST Repository

    Hong, Bingbing; Escobedo, Fernando; Panagiotopoulos, Athanassios Z.

    2010-01-01

    Diffusivities and viscosities of poly(ethylene oxide) (PEO) oligomer melts with 1 to 12 repeat units have been obtained from equilibrium molecular dynamics simulations using the TraPPE-UA force field. The simulations generated diffusion coefficients

  2. Atomistic simulation of CO 2 solubility in poly(ethylene oxide) oligomers

    KAUST Repository

    Hong, Bingbing; Panagiotopoulos, Athanassios Z.

    2013-01-01

    We have performed atomistic molecular dynamics simulations coupled with thermodynamic integration to obtain the excess chemical potential and pressure-composition phase diagrams for CO2 in poly(ethylene oxide) oligomers. Poly(ethylene oxide

  3. Molecular Dynamics Simulations of Silica Nanoparticles Grafted with Poly(ethylene oxide) Oligomer Chains

    KAUST Repository

    Hong, Bingbing; Panagiotopoulos, Athanassios Z.

    2012-01-01

    A molecular model of silica nanoparticles grafted with poly(ethylene oxide) oligomers has been developed for predicting the transport properties of nanoparticle organic-hybrid materials (NOHMs). Ungrafted silica nanoparticles in a medium of poly(ethylene

  4. Diffusivities and Viscosities of Poly(ethylene oxide) Oligomers

    KAUST Repository

    Hong, Bingbing

    2010-10-14

    Diffusivities and viscosities of poly(ethylene oxide) (PEO) oligomer melts with 1 to 12 repeat units have been obtained from equilibrium molecular dynamics simulations using the TraPPE-UA force field. The simulations generated diffusion coefficients with high accuracy for all of the molar masses studied, but the statistical uncertainties in the viscosity calculations were significantly larger for longer chains. There is good agreement of the calculated viscosities and densities with available experimental data, and thus, the simulations can be used to bridge gaps in the data and for extrapolations with respect to chain length, temperature, and pressure. We explored the convergence characteristics of the Green-Kubo formulas for different chain lengths and propose minimal production times required for convergence of the transport properties. The chain-length dependence of the transport properties suggests that neither Rouse nor reptation models are applicable in the short-chain regime investigated. © 2010 American Chemical Society.

  5. Atomistic simulation of CO 2 solubility in poly(ethylene oxide) oligomers

    KAUST Repository

    Hong, Bingbing

    2013-10-02

    We have performed atomistic molecular dynamics simulations coupled with thermodynamic integration to obtain the excess chemical potential and pressure-composition phase diagrams for CO2 in poly(ethylene oxide) oligomers. Poly(ethylene oxide) dimethyl ether, CH3O(CH 2CH2O)nCH3 (PEO for short) is a widely applied physical solvent that forms the major organic constituent of a class of novel nanoparticle-based absorbents. Good predictions were obtained for pressure-composition-density relations for CO2 + PEO oligomers (2 ≤ n ≤ 12), using the Potoff force field for PEO [J. Chem. Phys. 136, 044514 (2012)] together with the TraPPE model for CO2 [AIChE J. 47, 1676 (2001)]. Water effects on Henrys constant of CO2 in PEO have also been investigated. Addition of modest amounts of water in PEO produces a relatively small increase in Henrys constant. Dependence of the calculated Henrys constant on the weight percentage of water falls on a temperature-dependent master curve, irrespective of PEO chain length. © 2013 Taylor & Francis.

  6. Molecular Dynamics Simulations of Silica Nanoparticles Grafted with Poly(ethylene oxide) Oligomer Chains

    KAUST Repository

    Hong, Bingbing

    2012-03-01

    A molecular model of silica nanoparticles grafted with poly(ethylene oxide) oligomers has been developed for predicting the transport properties of nanoparticle organic-hybrid materials (NOHMs). Ungrafted silica nanoparticles in a medium of poly(ethylene oxide) oligomers were also simulated to clarify the effect of grafting on the dynamics of nanoparticles and chains. The model approximates nanoparticles as solid spheres and uses a united-atom representation for chains, including torsional and bond-bending interactions. The calculated viscosities from Green-Kubo relationships and temperature extrapolation are of the same order of magnitude as experimental data but show a smaller activation energy relative to real NOHMs systems. Grafted systems have higher viscosities, smaller diffusion coefficients, and slower chain dynamics than the ungrafted ones at high temperatures. At lower temperatures, grafted systems exhibit faster dynamics for both nanoparticles and chains relative to ungrafted systems, because of lower aggregation of particles and enhanced correlations between nanoparticles and chains. This agrees with the experimental observation that NOHMs have liquidlike behavior in the absence of a solvent. For both grafted and ungrafted systems at low temperatures, increasing chain length reduces the volume fraction of nanoparticles and accelerates the dynamics. However, at high temperatures, longer chains slow down nanoparticle diffusion. From the Stokes-Einstein relationship, it was determined that the coarse-grained treatment of nanoparticles leads to slip on the nanoparticle surfaces. Grafted systems obey the Stokes-Einstein relationship over the temperature range simulated, but ungrafted systems display deviations from it. © 2012 American Chemical Society.

  7. Enthalpies of solvation of ethylene oxide oligomers CH{sub 3}O(CH{sub 2}CH{sub 2}O){sub n}CH{sub 3} (n = 1 to 4) in different H-bonding solvents: Methanol, chloroform, and water. Group contribution method as applied to the polar oligomers

    Energy Technology Data Exchange (ETDEWEB)

    Barannikov, Vladimir P., E-mail: vpb@isc-ras.ru [Institute of Solution Chemistry, Russian Academy of Sciences, Academicheskaya Str. 1, Ivanovo 153045 (Russian Federation); Guseynov, Sabir S.; Vyugin, Anatoliy I. [Institute of Solution Chemistry, Russian Academy of Sciences, Academicheskaya Str. 1, Ivanovo 153045 (Russian Federation)

    2011-12-15

    Highlights: > Solvation enthalpy is found for ethylene oxide oligomers in chloroform and methanol. > Coefficients of solute-solute interaction are determined for oligomers in methanol. > Enthalpies of hydrogen bonding of oligomers with chloroform and water are estimated. > Additivity scheme is developed for describing enthalpies of solvation of oligomers. - Abstract: The enthalpies of solution and solvation of ethylene oxide oligomers CH{sub 3}O(CH{sub 2}CH{sub 2}O){sub n}CH{sub 3} (n = 1 to 4) in methanol and chloroform have been determined from calorimetric measurements at T = 298.15 K. The enthalpic coefficients of pairwise solute-solute interaction for methanol solutions have been calculated. The enthalpic characteristics of the oligomers in methanol, chloroform, water and tetrachloromethane have been compared. The hydrogen bonding of the oligomers with chloroform and water molecules is exhibited in the values of solvation enthalpy and coefficient of solute-solute interaction. This effect is not observed for methanol solvent. The thermochemical data evidence an existence of multi-centred hydrogen bonds in associates of polyethers with the solvent molecules. Enthalpies of hydrogen bonding of the oligomers with chloroform and water have been estimated. The additivity scheme has been developed to describe the enthalpies of solvation of ethylene oxide oligomers, unbranched monoethers and n-alkanes in chloroform, methanol, water, and tetrachloromethane. The correction parameters for contribution of repeated polar groups and correction term for methoxy-compounds have been introduced. The obtained group contributions permit to describe the enthalpies of solvation of unbranched monoethers and ethylene oxide oligomers in the solvents with standard deviation up to 0.6 kJ . mol{sup -1}. The values of group contributions and corrections are strongly influenced by solvent properties.

  8. 46 CFR 154.1725 - Ethylene oxide.

    Science.gov (United States)

    2010-10-01

    ... 46 Shipping 5 2010-10-01 2010-10-01 false Ethylene oxide. 154.1725 Section 154.1725 Shipping COAST....1725 Ethylene oxide. (a) A vessel carrying ethylene oxide must: (1) Have cargo piping, vent piping, and... space of an ethylene oxide cargo tank for a period of 30 days under the condition of paragraph (e) of...

  9. RESIDUAL RISK ASSESSMENT: ETHYLENE OXIDE ...

    Science.gov (United States)

    This document describes the residual risk assessment for the Ethylene Oxide Commercial Sterilization source category. For stationary sources, section 112 (f) of the Clean Air Act requires EPA to assess risks to human health and the environment following implementation of technology-based control standards. If these technology-based control standards do not provide an ample margin of safety, then EPA is required to promulgate addtional standards. This document describes the methodology and results of the residual risk assessment performed for the Ethylene Oxide Commercial Sterilization source category. The results of this analyiss will assist EPA in determining whether a residual risk rule for this source category is appropriate.

  10. 49 CFR 173.323 - Ethylene oxide.

    Science.gov (United States)

    2010-10-01

    ... 49 Transportation 2 2010-10-01 2010-10-01 false Ethylene oxide. 173.323 Section 173.323... SHIPMENTS AND PACKAGINGS Gases; Preparation and Packaging § 173.323 Ethylene oxide. (a) For packaging ethylene oxide in non-bulk packagings, silver mercury or any of its alloys or copper may not be used in any...

  11. 29 CFR 1910.1047 - Ethylene oxide.

    Science.gov (United States)

    2010-07-01

    ... 29 Labor 6 2010-07-01 2010-07-01 false Ethylene oxide. 1910.1047 Section 1910.1047 Labor... Ethylene oxide. (a) Scope and application. (1) This section applies to all occupational exposures to ethylene oxide (EtO), Chemical Abstracts Service Registry No. 75-21-8, except as provided in paragraph (a...

  12. Poly[(ethylene oxide)-co-(methylene ethylene oxide)]: A hydrolytically-degradable poly(ethylene oxide) platform

    OpenAIRE

    Lundberg, Pontus; Lee, Bongjae F.; van den Berg, Sebastiaan A.; Pressly, Eric D.; Lee, Annabelle; Hawker, Craig J.; Lynd, Nathaniel A.

    2012-01-01

    A facile method for imparting hydrolytic degradability to poly(ethylene oxide) (PEO), compatible with current PEGylation strategies, is presented. By incorporating methylene ethylene oxide (MEO) units into the parent PEO backbone, complete degradation was defined by the molar incorporation of MEO, and the structure of the degradation byproducts was consistent with an acid-catalyzed vinyl-ether hydrolysis mechanism. The hydrolytic degradation of poly[(ethylene oxide)-co-(methylene ethylene oxi...

  13. Poly(ethylene oxide) functionalization

    Science.gov (United States)

    Pratt, Russell Clayton

    2014-04-08

    A simple procedure is provided by which the hydroxyl termini of poly(ethylene oxide) can be appended with functional groups to a useful extent by reaction and precipitation. The polymer is dissolved in warmed toluene, treated with an excess of organic base and somewhat less of an excess of a reactive acylating reagent, reacted for several hours, then precipitated in isopropanol so that the product can be isolated as a solid, and salt byproducts are washed away. This procedure enables functionalization of the polymer while not requiring laborious purification steps such as solvent-solvent extraction or dialysis to remove undesirable side products.

  14. 29 CFR 1926.1147 - Ethylene oxide.

    Science.gov (United States)

    2010-07-01

    ... 29 Labor 8 2010-07-01 2010-07-01 false Ethylene oxide. 1926.1147 Section 1926.1147 Labor Regulations Relating to Labor (Continued) OCCUPATIONAL SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR... Ethylene oxide. Note: The requirements applicable to construction work under this section are identical to...

  15. 29 CFR 1915.1047 - Ethylene oxide.

    Science.gov (United States)

    2010-07-01

    ... 29 Labor 7 2010-07-01 2010-07-01 false Ethylene oxide. 1915.1047 Section 1915.1047 Labor Regulations Relating to Labor (Continued) OCCUPATIONAL SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR... § 1915.1047 Ethylene oxide. Note: The requirements applicable to shipyard employment under this section...

  16. Effect of phenolic oligomer on adhesion of poly (ethylene terephthalate) film laminated steel sheets by Electron Beam Curing method

    International Nuclear Information System (INIS)

    Masuhara, Kenichi; Mori, Koji; Koshiishi, Kenji; Sasaki, Takashi.

    1995-01-01

    Adhesion of poly (ethylene terephthalate) film by Electron Beam Curing (EBC) method which can be thought as an energy-saving process was studied for the purpose of bestowing economically design and distinctness of image on thermosetting high molecular weight polyester precoated steel sheets. Adhesion of EB curable resins onto metal is generally poor. In this report, addition of EB curable phenolic resole oligomer with bifunctional acrylates to the top coat used for precoated steel was studied in order to increase the adhesion of an EB curable adhesive, and it was found that the phenolic oligomer is tremendously effective for the improvement of adhesion. The reasons why the phenolic oligomer provides excellent adhesion were 1) elongation at break of the top coat to which the phenolic oligomer is added is little decreased by EB irradiation, and the formability does not reduce. 2) As the phenolic oligomer is unevenly distributed to the surface layer of the top coat, it is suggested that the contact frequency of the phenolic oligomer to the EB curable adhesive is so high that graft polymerization between them is liable to occur. (author)

  17. Poly[(ethylene oxide)-co-(methylene ethylene oxide)]: A hydrolytically-degradable poly(ethylene oxide) platform.

    Science.gov (United States)

    Lundberg, Pontus; Lee, Bongjae F; van den Berg, Sebastiaan A; Pressly, Eric D; Lee, Annabelle; Hawker, Craig J; Lynd, Nathaniel A

    2012-11-20

    A facile method for imparting hydrolytic degradability to poly(ethylene oxide) (PEO), compatible with current PEGylation strategies, is presented. By incorporating methylene ethylene oxide (MEO) units into the parent PEO backbone, complete degradation was defined by the molar incorporation of MEO, and the structure of the degradation byproducts was consistent with an acid-catalyzed vinyl-ether hydrolysis mechanism. The hydrolytic degradation of poly[(ethylene oxide)-co-(methylene ethylene oxide)] was pH-sensitive, with degradation at pH 5 being significantly faster than at pH 7.4 at 37 °C in PBS buffer while long-term stability could be obtained in either the solid-state or at pH 7.4 at 6 °C.

  18. Health Assessment Document for Ethylene Oxide

    Science.gov (United States)

    The largest single use of ethylene oxide is as an intermediate in the synthesis of ethylene glycol. However, small amounts of this epoxide are used as a sterilant or pesticide in commodities, pharmaceuticals, medical devices, tobacco, and other items, representing a considerable ...

  19. 21 CFR 172.770 - Ethylene oxide polymer.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Ethylene oxide polymer. 172.770 Section 172.770... CONSUMPTION Other Specific Usage Additives § 172.770 Ethylene oxide polymer. The polymer of ethylene oxide may... conditions. (a) It is the polymer of ethylene oxide having a minimum viscosity of 1,500 centipoises in a 1...

  20. 46 CFR 151.50-12 - Ethylene oxide.

    Science.gov (United States)

    2010-10-01

    ... 46 Shipping 5 2010-10-01 2010-10-01 false Ethylene oxide. 151.50-12 Section 151.50-12 Shipping... BULK LIQUID HAZARDOUS MATERIAL CARGOES Special Requirements § 151.50-12 Ethylene oxide. (a)(1) Ethylene... otherwise provided for in paragraph (a)(3) of this section. (2) Ethylene oxide shall be loaded at a...

  1. 21 CFR 880.6860 - Ethylene oxide gas sterilizer.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Ethylene oxide gas sterilizer. 880.6860 Section... Miscellaneous Devices § 880.6860 Ethylene oxide gas sterilizer. (a) Identification. An ethylene gas sterilizer is a nonportable device intended for use by a health care provider that uses ethylene oxide (ETO) to...

  2. Synthesis of α-hydroxy-ω-amino poly(ethylene oxide) and its use in reaction injection moulding (RIM)

    NARCIS (Netherlands)

    Loontjens, Ton J.A.; Scholtens, Boudewijn J.R.; Belt, Wil J.W.; Frisch, Kurt C.; Wong, Shaio-wen

    1993-01-01

    Computer simulations show that oligomers with two different terminal groups with dissimilar reactivities for isoeyanates give a delayed viscosity rise in polyurethanes. This is a desired behaviour for RIM processes. Therefore, an α-hydroxy-ω-amino poly(ethylene oxide) (HAPEO) has been prepared. The

  3. Biocatalytic conversion of ethylene to ethylene oxide using an engineered toluene monooxygenase.

    Science.gov (United States)

    Carlin, D A; Bertolani, S J; Siegel, J B

    2015-02-11

    Mutants of toluene o-xylene monooxygenase are demonstrated to oxidize ethylene to ethylene oxide in vivo at yields of >99%. The best mutant increases ethylene oxidation activity by >5500-fold relative to the native enzyme. This is the first report of a recombinant enzyme capable of carrying out this industrially significant chemical conversion.

  4. 21 CFR 880.6100 - Ethylene oxide gas aerator cabinet.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Ethylene oxide gas aerator cabinet. 880.6100... Miscellaneous Devices § 880.6100 Ethylene oxide gas aerator cabinet. (a) Identification. An ethyene oxide gas... required to remove residual ethylene oxide (ETO) from wrapped medical devices that have undergone ETO...

  5. 40 CFR 180.151 - Ethylene oxide; tolerances for residues.

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 23 2010-07-01 2010-07-01 false Ethylene oxide; tolerances for... § 180.151 Ethylene oxide; tolerances for residues. (a) General. (1) Tolerances are established for residues of the antimicrobial agent and insecticide ethylene oxide, when used as a postharvest fumigant in...

  6. Poly(ethylene oxide) surfactant polymers

    OpenAIRE

    VACHEETHASANEE, KATANCHALEE; WANG, SHUWU; QIU, YONGXING; MARCHANT, ROGER E.

    2004-01-01

    We report on a series of structurally well-defined surfactant polymers that undergo surface-induced self-assembly on hydrophobic biomaterial surfaces. The surfactant polymers consist of a poly(vinyl amine) backbone with poly(ethylene oxide) and hexanal pendant groups. The poly(vinyl amine) (PVAm) was synthesized by hydrolysis of poly(N-vinyl formamide) following free radical polymerization of N-vinyl formamide. Hexanal and aldehyde-terminated poly (ethyleneoxide) (PEO) were simultaneously att...

  7. Oxidation of Ethylene Carbonate on Li Metal Oxide Surfaces

    DEFF Research Database (Denmark)

    Østergaard, Thomas M.; Giordano, Livia; Castelli, Ivano Eligio

    2018-01-01

    Understanding the reactivity of the cathode surface is of key importance to the development of batteries. Here, density functional theory is applied to investigate the oxidative decomposition of the electrolyte component, ethylene carbonate (EC), on layered LixMO(2) oxide surfaces. We compare...

  8. [Quantitative analysis of urinary ethylene glycol in rats exposed to ethylene oxide].

    Science.gov (United States)

    Koga, M; Hori, H; Tanaka, I; Akiyama, T; Inoue, N

    1985-03-01

    A gas chromatographic method was used for determining ethylene glycol in urine. The analytical procedure is based on an azeotropic distillation and on esterification with n-butyl boronic acid. The linear calibration curve was obtained up to 500 micrograms/ml of ethylene glycol. The detection limit was estimated to be 10 micrograms/ml and relative standard deviation was 3.5% for 100 micrograms/ml of ethylene glycol. This method was applied to determine the urinary excretion of ethylene glycol in rats exposed to ethylene oxide at various concentrations (from 50 to 500 ppm). The excretion amounts of ethylene glycol were observed to be dependent on the concentration of ethylene oxide exposed.

  9. Parkinsonism secondary to ethylene oxide exposure

    Directory of Open Access Journals (Sweden)

    Egberto R. Barbosa

    1992-12-01

    Full Text Available Ethylene oxide is a gas widely used in the production of industrial chemicals. It is also used to sterilize heat-sensitive medical supplies. Previous reports of acute and chronic exposure have described neurotoxic effects like peripheral neuropathy and cognitive impairment. We describe a pure parkinsonian syndrome following acute ethylene oxide intoxication. A 39-years-old male was referred to our Movement Disorders Clinic tor evaluation of a parkinsonian syndrome. He was acutely exposed to ethylene oxide four years before and remained comatose for three days, and gradually regained consciousness.. At that time he showed a global parkinsonian syndrome including bradykinesia, rigidity and rest tremor, with a severe motor disability; no other neurological disorders were found. The symptomatology was partially controlled with biperidene and levodopa plus carbidopa. Two years later he developed L-dopa induced dyskinesias. Four years after the intoxication he was evaluated at our clinic. General examination showed no abnormalities. Neurologic examination revealed a normal menta1 status. Motor evaluation disclosed moderate bradykinesia, rigidity and rest tremor, shuffling gait, poor facial mimic, stooped posture, and his speech was low and monotonous; deep tendon reflexes were brisk. The Hoehn-Yahr disability score was degree IV. Routine laboratory and radiological exams showed results within normal limits. The CSF examination was normal. Brain computed tomography and magnetic ressonance were normal. A trial with bromocriptine and levodopa plus carbidopa did not improve dyskinesia, and he was put on a schedule including amantadine and biperidene with improvement to grade III in Hoehn-Yahr scale. In the present case there was a clear relation between the acute exogenous intoxication and irreversible parkinsonism. No other causes for the condition were identified.

  10. Mesomorphic structure of poly(styrene)-block-poly(4-vinylpyridine) with oligo(ethylene oxide)sulfonic acid side chains as a model for molecularly reinforced polymer electrolyte

    NARCIS (Netherlands)

    Kosonen, H; Valkama, S; Hartikainen, J; Eerikainen, H; Torkkeli, M; Jokela, K; Serimaa, R; Sundholm, F; ten Brinke, G; Ikkala, O; Eerikäinen, Hannele

    2002-01-01

    We report self-organized polymer electrolytes based on poly(styrene)-block-poly(4-vinylpyridine) (PS-block-P4VP). Liquidlike ethylene oxide (EO) oligomers with sulfonic acid end groups are bonded to the P4VP block, leading to comb-shaped supramolecules with the PS-block-P4VP backbone. Lithium

  11. Poly(ethylene oxide) surfactant polymers.

    Science.gov (United States)

    Vacheethasanee, Katanchalee; Wang, Shuwu; Qiu, Yongxing; Marchant, Roger E

    2004-01-01

    We report on a series of structurally well-defined surfactant polymers that undergo surface-induced self-assembly on hydrophobic biomaterial surfaces. The surfactant polymers consist of a poly(vinyl amine) backbone with poly(ethylene oxide) and hexanal pendant groups. The poly(vinyl amine) (PVAm) was synthesized by hydrolysis of poly(N-vinyl formamide) following free radical polymerization of N-vinyl formamide. Hexanal and aldehyde-terminated poly(ethylene oxide) (PEO) were simultaneously attached to PVAm via reductive amination. Surfactant polymers with different PEO:hexanal ratios and hydrophilic/hydrophobic balances were prepared, and characterized by FT-IR, 1H-NMR and XPS spectroscopies. Surface active properties at the air/water interface were determined by surface tension measurements. Surface activity at a solid surface/water interface was demonstrated by atomic force microscopy, showing epitaxially molecular alignment for surfactant polymers adsorbed on highly oriented pyrolytic graphite. The surfactant polymers described in this report can be adapted for simple non-covalent surface modification of biomaterials and hydrophobic surfaces to provide highly hydrated interfaces.

  12. Radicidation as an alternative for ethylene oxide

    Energy Technology Data Exchange (ETDEWEB)

    Farkas, J [Koezponti Elelmiszeripari Kutato Intezet, Budapest (Hungary)

    1985-01-01

    The application of ethylene oxide to sterilize dry foodstuff additions proved to be a source of danger both for the personnel of the food preservation industry and for the consumers due to the residue of some chemicals and toxic reaction products which can not be removed from the foodstuff. A more advantageous and less harmful alternative for the reduction of the number of germs is offered by using ionizing radiation. Based on a great number of references, the applicability and effectiveness of radicidation for the preservation of spices, dry vegetable powders, sugar, thickening materials, protein and enzyme products were confirmed. Regarding the economic aspects, this method can be compared with the traditional chemical treatment. Commercial licenses have been issued by the health organizations of 12 countries.

  13. Radicidation as an alternative for ethylene oxide

    International Nuclear Information System (INIS)

    Farkas, Jozsef

    1985-01-01

    The application of ethylene oxide to sterilize dry foodstuff additions proved to be a source of danger both for the personnel of the food preservation industry and for the consumers due to the residue of some chemicals and toxic reaction products which can not be removed from the foodstuff. A more advantageous and less harmful alternative for the reduction of the number of germs is offered by using ionizing radiation. Based on a great number of references, the applicability and effectiveness of radicidation for the preservation of spices, dry vegetable powders, sugar, thickening materials, protein and enzyme products were confirmed. Regarding the economic aspects, this method can be compared with the traditional chemical treatment. Commercial licenses have been issued by the health organizations of 12 countries. (V.N.)

  14. Reactions of organic zinc- and cadmium elementoxides with ethylene oxide

    International Nuclear Information System (INIS)

    Dodonov, V.A.; Krasnov, Yu.N.

    1980-01-01

    Studied are reactions of triphenylmethoxy, -triphenylsiloxyethylzinc and -cadmium with ethylene oxide in ratio of 1:1. Reactions have been carried out in tolyene solutions in ampules sealed in argon atmosphere. It is found that interaction of triphenylsiloxy-, triphenylmethoxyethylcadmium and triphenylsiloxyethylzinc with ethylene oxide occurs at the metal-carbon bond with formation of implantation products. Triphenylmethoxyethylzinc reacts with ethylene oxide both at the metal-carbon and metal-oxygen bonds. Alkoxytriphenylsiloxyderivatives of zinc and cadmium are thermally instable and decompose under the conditions of reaction (130 deg C) with migration of phenyl group from silicon to zinc or cadmium, giving alkoxyphenylderivative and with bensene splitting out

  15. Combined gas-phase oxidation of methane and ethylene

    International Nuclear Information System (INIS)

    Pogosyan, N.M.; Pogosyan, M.D.

    2009-01-01

    It is established that depending on the reaction conditions combined oxidation of methane and ethylene may result in ethylene and propylene oxides with high selectivity with respect to the process, where in the initial reaction mixture methane is replaced by the same quantity of nitrogen. The formed additional methyl radicals increase the yield of all reaction products except CO. At low temperatures methyl radicals react with oxygen resulting in methyl peroxide radicals, which in turn, reacting with ethylene provide its epoxidation and formation of other oxygen-containing products. At high temperatures as a result of addition reaction between methyl radicals and ethylene, propyl radicals are formed that, in turn yield propylene. Alongside with positive influence on the yield of reaction products, methane exerts negative influence upon the conversion, that is it decreases the rate of ethylene and oxygen conversion, simultaneously decreasing significantly the yield of CO

  16. Effect of gamma radiation and ethylene oxide on neomycin sulphate

    International Nuclear Information System (INIS)

    Gopal, N.G.S.; Rajagopalan, S.

    1981-01-01

    Neomycin is affected by ethylene oxide but not by gamma radiation (2.75 Mrad). Differential refractometry is more advantageous in quantitating neomycin A, B and C than is the ninhydrin method. (Auth.)

  17. effects of ethylene oxide resterilisation and in-vitro degradation

    African Journals Online (AJOL)

    2013-06-01

    Jun 1, 2013 ... Subjects: Two composite meshes were used in the study: One mesh is ... Ethylene oxide gas sterilisation was performed ... were completed for control and resterilisation specimens. .... lowers in-hospital care expenses.

  18. Evaluating OSHA's ethylene oxide standard: exposure determinants in Massachusetts hospitals.

    Science.gov (United States)

    LaMontagne, A D; Kelsey, K T

    2001-03-01

    This study sought to identify determinants of workplace exposures to ethylene oxide to assess the effect of the Occupational Safety and Health Administration's (OSHA's) 1984 ethylene oxide standard. An in-depth survey of all hospitals in Massachusetts that used ethylene oxide from 1990 through 1992 (96% participation, N = 90) was conducted. Three types of exposure events were modeled with logistic regression: exceeding the 8-hour action level, exceeding the 15-minute excursion limit, and worker exposures during unmeasured accidental releases. Covariates were drawn from data representing an ecologic framework including direct and indirect potential exposure determinants. After adjustment for frequencies of ethylene oxide use and exposure monitoring, a significant inverse relation was observed between exceeding the action level and the use of combined sterilizer-aerators, an engineering control technology developed after the passage of the OSHA standard. Conversely, the use of positive-pressure sterilizers that employ ethylene oxide gas mixtures was strongly related to both exceeding the excursion limit and the occurrence of accidental releases. These findings provide evidence of a positive effect of OSHA's ethylene oxide standard and specific targets for future prevention and control efforts.

  19. Simulation of 3D mesoscale structure formation in concentrated aqueous solution of the triblock polymer surfactants (ethylene oxide)(13)(propylene oxide)(30)(ethylene oxide)(13) and (propylene oxide)(19)(ethylene oxide)(33)(propylene oxide)(19). Application of dynamic mean-field density functional theory

    NARCIS (Netherlands)

    van Vlimmeren, BAC; Maurits, NM; Zvelindovsky, AV; Sevink, GJA; Fraaije, JGEM

    1999-01-01

    We simulate the microphase separation dynamics of aqueous solutions of the triblock polymer surfactants (ethylene oxide)(13)(propylene oxide)(30)(ethylene oxide)(13) and (propylene oxide)(19)(ethylene oxide)(33)(propylene oxide)(19) by a dynamic variant of mean-field density functional theory for

  20. Theoretical investigation of the reaction of Mn+ with ethylene oxide.

    Science.gov (United States)

    Li, Yuanyuan; Guo, Wenyue; Zhao, Lianming; Liu, Zhaochun; Lu, Xiaoqing; Shan, Honghong

    2012-01-12

    The potential energy surfaces of Mn(+) reaction with ethylene oxide in both the septet and quintet states are investigated at the B3LYP/DZVP level of theory. The reaction paths leading to the products of MnO(+), MnO, MnCH(2)(+), MnCH(3), and MnH(+) are described in detail. Two types of encounter complexes of Mn(+) with ethylene oxide are formed because of attachments of the metal at different sites of ethylene oxide, i.e., the O atom and the CC bond. Mn(+) would insert into a C-O bond or the C-C bond of ethylene oxide to form two different intermediates prior to forming various products. MnO(+)/MnO and MnH(+) are formed in the C-O activation mechanism, while both C-O and C-C activations account for the MnCH(2)(+)/MnCH(3) formation. Products MnO(+), MnCH(2)(+), and MnH(+) could be formed adiabatically on the quintet surface, while formation of MnO and MnCH(3) is endothermic on the PESs with both spins. In agreement with the experimental observations, the excited state a(5)D is calculated to be more reactive than the ground state a(7)S. This theoretical work sheds new light on the experimental observations and provides fundamental understanding of the reaction mechanism of ethylene oxide with transition metal cations.

  1. The oxidation of copper catalysts during ethylene epoxidation.

    Science.gov (United States)

    Greiner, M T; Jones, T E; Johnson, B E; Rocha, T C R; Wang, Z J; Armbrüster, M; Willinger, M; Knop-Gericke, A; Schlögl, R

    2015-10-14

    The oxidation of copper catalysts during ethylene epoxidation was characterized using in situ photoemission spectroscopy and electron microscopy. Gas chromatography, proton-transfer reaction mass spectrometry and electron-ionization mass spectrometry were used to characterize the catalytic properties of the oxidized copper. We find that copper corrodes during epoxidation in a 1 : 1 mixture of oxygen and ethylene. The catalyst corrosion passes through several stages, beginning with the formation of an O-terminated surface, followed by the formation of Cu2O scale and eventually a CuO scale. The oxidized catalyst exhibits measurable activity for ethylene epoxidation, but with a low selectivity of 8/2500) Cu2O forms and eventually covers the surface.

  2. Anaphylaxis to ethylene oxide - a rare and overlooked phenomenon?

    DEFF Research Database (Denmark)

    Bache, Søren; Petersen, J T; Garvey, L H

    2011-01-01

    Spina bifida patients have been reported to be at increased risk of anaphylactic reactions during general anaesthesia. Following a reaction, latex is often incriminated as spina bifida patients are known to have an increased incidence of latex allergy. Ethylene oxide (EO) has recently been...

  3. 78 FR 24738 - Ethylene Oxide; Receipt of Application for Emergency Exemption, Solicitation of Public Comment

    Science.gov (United States)

    2013-04-26

    ... ENVIRONMENTAL PROTECTION AGENCY [EPA-HQ-OPP-2013-0276; FRL-9385-2] Ethylene Oxide; Receipt of... ethylene oxide (CAS No. 75-21-8) to sterilize the interior surfaces of enclosed animal isolator units to... APHIS has requested the EPA Administrator to issue a quarantine exemption for the use of ethylene oxide...

  4. 21 CFR 872.3450 - Ethylene oxide homopolymer and/or karaya denture adhesive.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Ethylene oxide homopolymer and/or karaya denture... HUMAN SERVICES (CONTINUED) MEDICAL DEVICES DENTAL DEVICES Prosthetic Devices § 872.3450 Ethylene oxide homopolymer and/or karaya denture adhesive. (a) Identification. Ethylene oxide homopolymer and/or karaya...

  5. 40 CFR 721.3680 - Ethylene oxide adduct of fatty acid ester with pentaerythritol.

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 30 2010-07-01 2010-07-01 false Ethylene oxide adduct of fatty acid... New Uses for Specific Chemical Substances § 721.3680 Ethylene oxide adduct of fatty acid ester with... identified generically as ethylene oxide adduct of fatty acid ester with pentaerythritol (PMN P-91-442) is...

  6. 46 CFR 154.1730 - Ethylene oxide: Loading and off loading.

    Science.gov (United States)

    2010-10-01

    ... 46 Shipping 5 2010-10-01 2010-10-01 false Ethylene oxide: Loading and off loading. 154.1730... Operating Requirements § 154.1730 Ethylene oxide: Loading and off loading. (a) The master shall ensure that before ethylene oxide is loaded into a cargo tank: (1) The tank is thoroughly clean, dry, and free of...

  7. 21 CFR 872.3410 - Ethylene oxide homopolymer and/or carboxymethylcellulose sodium denture adhesive.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Ethylene oxide homopolymer and/or....3410 Ethylene oxide homopolymer and/or carboxymethylcellulose sodium denture adhesive. (a) Identification. An ethylene oxide homopolymer and/or carboxymethylcellulose sodium denture adhesive is a device...

  8. 40 CFR 721.3700 - Fatty acid, ester with styrenated phenol, ethylene oxide adduct.

    Science.gov (United States)

    2010-07-01

    ... phenol, ethylene oxide adduct. 721.3700 Section 721.3700 Protection of Environment ENVIRONMENTAL..., ethylene oxide adduct. (a) Chemical substances and significant new uses subject to reporting. (1) The chemical substance identified generically as fatty acid, ester with styrenated phenol, ethylene oxide...

  9. Mechanisms leading to oligomers and SOA through aqueous photooxidation: insights from OH radical oxidation of acetic acid and methylglyoxal

    Directory of Open Access Journals (Sweden)

    Y. Tan

    2012-01-01

    Full Text Available Previous experiments have demonstrated that the aqueous OH radical oxidation of methylglyoxal produces low volatility products including pyruvate, oxalate and oligomers. These products are found predominantly in the particle phase in the atmosphere, suggesting that methylglyoxal is a precursor of secondary organic aerosol (SOA. Acetic acid plays a central role in the aqueous oxidation of methylglyoxal and it is a ubiquitous product of gas phase photochemistry, making it a potential "aqueous" SOA precursor in its own right. However, the fate of acetic acid upon aqueous-phase oxidation is not well understood. In this research, acetic acid (20 μM–10 mM was oxidized by OH radicals, and pyruvic acid and methylglyoxal experimental samples were analyzed using new analytical methods, in order to better understand the formation of SOA from acetic acid and methylglyoxal. Glyoxylic, glycolic, and oxalic acids formed from acetic acid and OH radicals. In contrast to the aqueous OH radical oxidation of methylglyoxal, the aqueous OH radical oxidation of acetic acid did not produce succinic acid and oligomers. This suggests that the methylgloxal-derived oligomers do not form through the acid catalyzed esterification pathway proposed previously. Using results from these experiments, radical mechanisms responsible for oligomer formation from methylglyoxal oxidation in clouds and wet aerosols are proposed. The importance of acetic acid/acetate as an SOA precursor is also discussed. We hypothesize that this and similar chemistry is central to the daytime formation of oligomers in wet aerosols.

  10. Removal of ethylene oxide from waste gases by absorption

    Directory of Open Access Journals (Sweden)

    Arsenijević Zorana Lj.

    2011-01-01

    Full Text Available Ethylene oxide (EtO is an organic compound, which is used as starting material in the production of polymers and as sterilizing agent for thermolabile materials. Although ethylene oxide is not common as an organic pollutant, its removal from numerous emission sources (e.g. ethylene oxide production plants or food and pharmaceutical sterilizing units is of the crucial importance because of its mutagenic, teratogenic and cancerogenic effect on human health. The objective of this paper is the experimental investigation of ethylene oxide (EtO absorption in diluted aqueous solution of sulfuric acid in order to evaluate the applicability of this procedure as well as to obtain project parameters for industrial plant realization. It was found that absorption is suitable as the fist step in the purification treatment of high EtO concentrations in the emission gases. According to the literature data, the basic parameter that defines the scrubber efficiency is the contact time, i.e. the ratio of packing height in scrubber and velocity of gas mixture. To investigate the characteristics of wet treatment in a broad range of contact time, part of experimental studies were conducted in the system with two and with three scrubbers in series. The obtained experimental results show that the high degree of EtO removal can be achieved (>98% when the contact time is sufficiently long (about 25 s. The process is effective until the concentration of formed glycol in the solution reaches value of about 20%. The process is safe and there is no danger of ignition and explosion of air and EtO mixture, although at the entrance to the scrubber EtO concentrations are significantly above the lower explosive limit.

  11. Performance limitations of polymer electrolytes based on ethylene oxide polymers

    International Nuclear Information System (INIS)

    Buriez, Olivier; Han, Yong Bong; Hou, Jun; Kerr, John B.; Qiao, Jun; Sloop, Steven E.; Tian, Minmin; Wang, Shanger

    1999-01-01

    Studies of polymer electrolyte solutions for lithium-polymer batteries are described. Two different salts, lithium bis(trifluoromethanesulfonyl)imide (LiTFSI) and lithium trifluoromethanesulfonate (LiTf), were dissolved in a variety of polymers. The structures were all based upon the ethylene oxide unit for lithium ion solvation and both linear and comb-branch polymer architectures have been examined. Conductivity, salt diffusion coefficient and transference number measurements demonstrate the superior transport properties of the LiTFSI salt over LiTf. Data obtained on all of these polymers combined with LiTFSI salts suggest that there is a limit to the conductivity achievable at room temperature, at least for hosts containing ethylene oxide units. The apparent conductivity limit is 5 x 10-5 S/cm at 25 C. Providing that the polymer chain segment containing the ethylene oxide units is at least 5-6 units long there appears to be little influence of the polymer framework to which the solvating groups are attached. To provide adequate separator function, the mechanical properties may be disconnected from the transport properties by selection of an appropriate architecture combined with an adequately long ethylene oxide chain. For both bulk and interfacial transport of the lithium ions, conductivity data alone is insufficient to understand the processes that occur. Lithium ion transference numbers and salt diffusion coefficients also play a major role in the observed behavior and the transport properties of these polymer electrolyte solutions appear to be quite inadequate for ambient temperature performance. At present, this restricts the use of such systems to high temperature applications. Several suggestions are given to overcome these obstacles

  12. Intermolecular potential energy surface and thermophysical properties of ethylene oxide.

    Science.gov (United States)

    Crusius, Johann-Philipp; Hellmann, Robert; Hassel, Egon; Bich, Eckard

    2014-10-28

    A six-dimensional potential energy hypersurface (PES) for two interacting rigid ethylene oxide (C2H4O) molecules was determined from high-level quantum-chemical ab initio calculations. The counterpoise-corrected supermolecular approach at the MP2 and CCSD(T) levels of theory was utilized to determine interaction energies for 10178 configurations of two molecules. An analytical site-site potential function with 19 sites per ethylene oxide molecule was fitted to the interaction energies and fine tuned to agree with data for the second acoustic virial coefficient from accurate speed of sound measurements. The PES was validated by computing the second virial coefficient, shear viscosity, and thermal conductivity. The values of these properties are substantiated by the best experimental data as they tend to fall within the uncertainty intervals and also obey the experimental temperature functions, except for viscosity, where experimental data are insufficient. Due to the lack of reliable data, especially for the transport properties, our calculated values are currently the most accurate estimates for these properties of ethylene oxide.

  13. Identification of chlorinated oligomers formed during anodic oxidation of phenol in the presence of chloride

    International Nuclear Information System (INIS)

    Chen, Linxi; Campo, Pablo; Kupferle, Margaret J.

    2015-01-01

    Graphical abstract: - Highlights: • By-products from anodic oxidation of phenol in the presence of chloride are investigated. • Chlorinated oligomer formation is demonstrated by LC-QTOF-MS. • They have structures similar to triclosan and polychlorinated dibenzo-p-dioxins. - Abstract: Chlorinated oligomer intermediates formed during the anodic electrochemical oxidation of phenol with a boron-doped diamond electrode were studied at two different concentrations of chloride (5 mM and 50 mM). Under the same ionic strength, with sodium sulfate being the make-up ion, a 10-fold increase in Cl − led to removal rates 10.8, 1.5, and 1.4 times higher for phenol, TOC, and COD, respectively. Mono-, di- and trichlorophenols resulting from electrophilic substitution were the identified by-products. Nevertheless, discrepancies between theoretical and measured TOC values along with gaps in the mass balance of chlorine-containing species indicated the formation of unaccounted-for chlorinated by-products. Accurate mass measurements by liquid chromatography quadrupole time-of-flight mass spectrometry and MS-MS fragmentation spectra showed that additional compounds formed were dimers and trimers of phenol with structures similar to triclosan and polychlorinated dibenzo-p-dioxins

  14. Identification of chlorinated oligomers formed during anodic oxidation of phenol in the presence of chloride

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Linxi; Campo, Pablo; Kupferle, Margaret J., E-mail: margaret.kupferle@uc.edu

    2015-02-11

    Graphical abstract: - Highlights: • By-products from anodic oxidation of phenol in the presence of chloride are investigated. • Chlorinated oligomer formation is demonstrated by LC-QTOF-MS. • They have structures similar to triclosan and polychlorinated dibenzo-p-dioxins. - Abstract: Chlorinated oligomer intermediates formed during the anodic electrochemical oxidation of phenol with a boron-doped diamond electrode were studied at two different concentrations of chloride (5 mM and 50 mM). Under the same ionic strength, with sodium sulfate being the make-up ion, a 10-fold increase in Cl{sup −} led to removal rates 10.8, 1.5, and 1.4 times higher for phenol, TOC, and COD, respectively. Mono-, di- and trichlorophenols resulting from electrophilic substitution were the identified by-products. Nevertheless, discrepancies between theoretical and measured TOC values along with gaps in the mass balance of chlorine-containing species indicated the formation of unaccounted-for chlorinated by-products. Accurate mass measurements by liquid chromatography quadrupole time-of-flight mass spectrometry and MS-MS fragmentation spectra showed that additional compounds formed were dimers and trimers of phenol with structures similar to triclosan and polychlorinated dibenzo-p-dioxins.

  15. Ion-molecule reactions in the binary mixture of ethylene oxide and trioxane, 1

    International Nuclear Information System (INIS)

    Kumakura, Minoru; Sugiura, Toshio.

    1977-01-01

    The formation mechanism of protonated molecular ions by cross-reactions in ethylene oxide-trioxane mixtures has been studied with use of a modified time-of-flight mass spectrometer. The precursors of the product ions were determined by analysis of the fine structure of their ionization efficiency curves using deuterated ethylene oxide. Protonated ethylene oxide is formed by the hydrogen atom transfer reaction of ethylene oxide molecular ion with trioxane, and protonated trioxane by the proton transfer reaction of CHO + (from ethylene oxide) with trioxane. In the ion-molecule reactions of ethylene-d 4 oxide-trioxane mixtures, appreciable isotope effect was observed. The CHO + from ethylene oxide is an important reactant ion as compared with that from trioxane in the proton transfer reaction, and CHO + from ethylene oxide was suggested as a thermal reactive ion. The order of proton affinity could be estimated from the proton transfer reactions involving CHO + . It was found that the proton affinity of trioxane is smaller than that of ethylene oxide. (auth.)

  16. Ethylene, nitric oxide and haemoglobins in plant tolerance to flooding

    DEFF Research Database (Denmark)

    Mur, Luis A J; Gupta, Kapuganti J; Chakraborty, U

    2015-01-01

    -tolerant species Rumex palustris and the model plant Arabidopsis thaliana have been extensively exploited to reveal some key molecular events. Our groups have recently demonstrated that nitric oxide (NO) triggers the biosynthesis of ethylene during stress and that NO plays key roles in PCD and the hyponastic......As much as 12% of the world's soils may suffer excess water so that flooding is a major limiting factor on crop production in many areas. Plants attempt to deal with submergence by forming root aerenchyma to facilitate oxygen diffusion from the shoot to the root, initiating a hyponastic response....... This chapter will detail our understanding of the roles of ethylene, NO and haemoglobin in flooding stress....

  17. Deformation of confined poly(ethylene oxide) in multilayer films.

    Science.gov (United States)

    Lai, Chuan-Yar; Hiltner, Anne; Baer, Eric; Korley, LaShanda T J

    2012-04-01

    The effect of confinement on the deformation behavior of poly(ethylene oxide) (PEO) was studied using melt processed coextruded poly(ethylene-co-acrylic acid) (EAA) and PEO multilayer films with varying PEO layer thicknesses from 3600 to 25 nm. The deformation mechanism was found to shift as layer thickness was decreased between 510 and 125 nm, from typical axial alignment of the crystalline fraction, as seen in bulk materials, to nonuniform micronecking mechanisms found in solution-grown single crystals. This change was evaluated via tensile testing, wide-angle X-ray diffraction (WAXD), atomic force microscopy (AFM), and differential scanning calorimetry (DSC). With the commercially relevant method of melt coextrusion, we were able to overcome the limitations to the testing of solution-grown single crystals, and the artifacts that occur from their handling, and bridged the gap in knowledge between thick bulk materials and thin single crystals.

  18. [Carcinogenic activity of ethylene oxide and its reaction products 2-chloroethanol, 2-bromoethanol, ethylene glycol and diethylene glycol. I. Carcinogenicity of ethylene oxide in comparison with 1,2-propylene oxide after subcutaneous administration in mice (author's transl)].

    Science.gov (United States)

    Dunkelberg, H

    1981-12-01

    Ethylene oxide is an important initial product for a number of organic compounds and, in addition, is used in the medical field for sterilization. The aim of our experiments was to test ethylene oxide and, as a comparative substance, 1,2-propylene oxide in respect to their cancerogenic effectiveness in animal experiments. Ethylene oxide was administered subcutaneously in three dosages (1.0; 0.3 and 0.1 mg single dosage per mouse) once per week to groups of 100 female NMRI mice respectively. In the case of 1,2-propylene oxide, four dosages were used (2.5; 1.0; 0.3 and 0.1 mg single dosage per mouse). The vehicle was tricaprylin. Administrations were carried out over a period of 95 weeks. The mean total dosage per mouse in the case of ethylene oxide amounted to 64.4; 22.7, and 7.3 mg and, in the case of propylene oxide, to 165.4; 72.8; 21.7 and 6.8 mg. Both substances induced local tumours depending upon the dosage. There were mostly fibrosarcomas. In the case of the groups treated with ethylene oxide the frequency was between 11 and 5% and in the case of the groups treated with 1,2-propylene oxide this was between 16 and 2%. The cancerogenic effect of ethylene oxide and 1,2-propylene oxide determined in animal experiments could, therefore, be confirmed statistically. On the basis of the results presented in this paper, new aspects have arisen for the medical evaluation of ethylene oxide residues in the field of manufacturing and use and in respect to the TLV.

  19. Poly(ethylene oxide)–Poly(propylene oxide)-Based Copolymers for ...

    African Journals Online (AJOL)

    Amphiphilic poly(ethylene oxide)–poly(propylene oxide) (PEO–PPO)-based copolymers are thermoresponsive materials having aggregation properties in aqueous medium. As hydrosolubilizers of poorly water-soluble drugs and improved stability of sensitive agents, these materials have been investigated for improvement ...

  20. Synthesis of poly(ethylene oxide)-silica hybrids

    International Nuclear Information System (INIS)

    Ishak Manaf

    2002-01-01

    A hybrid material incorporating silica networks in poly (ethylene oxide) was produced using the sol-gel process from solution mixtures of poly (ethylene oxide) dissolved in water and partially polymerized tetraethylorthosilicate (TEOS) with and without compatibilisation agent. These mixtures were converted into films by solvent evaporation and drying them in an air-circulating oven at 60 degree C. Depending on the alkoxysilane solution composition and several mixing parameters, different morphologies were obtained, varying from semi-interpenetrating networks of PEO within highly cross linked silica chains, to finely dispersed heterogeneous system exhibiting either co-continuous or particulate microstructure. The influence of pH, type of solvents, mixing temperatures and time, as well as the nature of compatibiliser was found to be extremely important in controlling the morphology and properties of the fine hybrid films. It was found that compatibilisation of PEO-SiO 2 hybrid system is achieved exclusively with the use of γ-glycidyloxypropyltrimethoxysilane (GOTMS) coupling agent. (Author)

  1. Radiochemical oxidation of an ethylene-propylene-hexadiene terpolymer

    International Nuclear Information System (INIS)

    Verdu, J.; Pinel, B.; Gueguen, V.; Audouin, L.

    1996-01-01

    The γ ray initiated oxidation of an ethylene-propylene-hexadiene terpolymer (molar ratios 87/12/1) was studied by IR spectrophotometry in the 40-90 deg C temperature range, with dose rates varying from 10 to 2500 Gy h -1 and integrated doses up to 100 kGy. Bulk (∼ 8 mm) and thin (∼ 0.1 mm) samples were studied. It appears that the oxidation is diffusion controlled in the bulk samples and non diffusion controlled in thin films. A kinetic study of IR spectral changes in these latter reveals that vinylene groups of the hexadiene monomer unit disappear in the early period of exposure, presumably by addition reactions with peroxy radicals. A very simplified mechanistic scheme allows a satisfying modelling of this process whose rate is almost proportional to the dose rate (irradiation intensity). (authors)

  2. Amino siloxane oligomer-linked graphene oxide as an efficient adsorbent for removal of Pb(II) from wastewater

    International Nuclear Information System (INIS)

    Luo, Shenglian; Xu, Xiangli; Zhou, Guiyin; Liu, Chengbin; Tang, Yanhong; Liu, Yutang

    2014-01-01

    Graphical abstract: A high performance sorbent, oligomer-linked graphene oxide, was prepared by using oligomeric poly3-aminopropyltriethoxysilane as crosslinking agents. The sorbent could selectively remove Pb(II) with high adsorption capacity. - Highlights: • Oligomer-linked graphene oxide sharply fattened function groups. • The sorbent exhibited high adsorption capacity toward Pb(II). • Pb, Cu and Fe were selectively removed from smelter industrial effluent. • The sorption could be conducted at a wide pH range of about 4.0–7.0. - Abstract: A high performance sorbent, oligomer-linked graphene oxide (GO) composite, was prepared through simple cross-linking reactions between GO sheets and poly3-aminopropyltriethoxysilane (PAS) oligomers as crosslinking agents. The three-dimensional PAS oligomers prevented GO sheets from aggregation, provided foreign molecules with easier access, and introduced a large amount of amino functional groups. The morphology, structure and property of the PAS-GO composite were determined by scanning electron microscope (SEM), transmission electron microscope (TEM), Fourie transform infrared (FTIR), X-ray diffractometer (XRD), thermogravimetric analysis (TGA) and X-ray photoelectron spectroscopy (XPS). The adsorption performance of PAS-GO was investigated in removing Pb(II) ions from water. Compared to 3-aminopropyltriethoxysilane functionalized GO (AS-GO) which was prepared by the direct reaction between 3-aminopropyltriethoxysilane and GO, PAS-GO exhibited much higher adsorptivity toward Pb(II) with the maximum adsorption capacity of 312.5 mg/g at 303 K and furthermore the maximum adsorption capacity increased with increasing temperature. The adsorption could be conducted in a wide pH range of 4.0–7.0. Importantly, PAS-GO had a priority tendency to adsorb Pb, Cu and Fe from a mixed solution of metal ions, especially from a practical industrial effluent

  3. A physiologically based toxicokinetic model for inhaled ethylene and ethylene oxide in mouse, rat, and human.

    Science.gov (United States)

    Filser, Johannes Georg; Klein, Dominik

    2018-04-01

    Ethylene (ET) is the largest volume organic chemical. Mammals metabolize the olefin to ethylene oxide (EO), another important industrial chemical. The epoxide alkylates macromolecules and has mutagenic and carcinogenic properties. In order to estimate the EO burden in mice, rats, and humans resulting from inhalation exposure to gaseous ET or EO, a physiological toxicokinetic model was developed. It consists of the compartments lung, richly perfused tissues, kidneys, muscle, fat, arterial blood, venous blood, and liver containing the sub-compartment endoplasmic reticulum. Modeled ET metabolism is mediated by hepatic cytochrome P450 2E1, EO metabolism by hepatic microsomal epoxide hydrolase or cytosolic glutathione S-transferase in various tissues. EO is also spontaneously hydrolyzed or conjugated with glutathione. The model was validated on experimental data collected in mice, rats, and humans. Modeled were uptake by inhalation, wash-in-wash-out effect in the upper respiratory airways, distribution into tissues and organs, elimination via exhalation and metabolism, and formation of 2-hydroxyethyl adducts with hemoglobin and DNA. Simulated concentration-time courses of ET or EO in inhaled (gas uptake studies) or exhaled air, and of EO in blood during exposures to ET or EO agreed excellently with measured data. Predicted levels of adducts with DNA and hemoglobin, induced by ET or EO, agreed with reported levels. Exposures to 10000 ppm ET were predicted to induce the same adduct levels as EO exposures to 3.95 (mice), 5.67 (rats), or 0.313 ppm (humans). The model is concluded to be applicable for assessing health risks from inhalation exposure to ET or EO. Copyright © 2017 The Author(s). Published by Elsevier B.V. All rights reserved.

  4. Competitive intramolecular hydrogen bonding in oligo(ethylene oxide) substituted quadruple hydrogen bonded systems

    NARCIS (Netherlands)

    Greef, de T.F.A.; Nieuwenhuizen, M.M.L.; Sijbesma, R.P.; Meijer, E.W.

    2010-01-01

    A series of oligo(ethylene oxide) (oligoEO) substituted 2-ureido-pyrimidinones (UPy), differing in the number of ethylene oxide units and the length of the aliphatic spacer connecting the oligoEO side chain with the UPy group, have been prepared. It was found that variation in these structural

  5. Novel and existing data for a future physiological toxicokinetic model of ethylene and its metabolite ethylene oxide in mouse, rat, and human.

    Science.gov (United States)

    Filser, Johannes Georg; Artati, Anna; Li, Qiang; Pütz, Christian; Semder, Brigitte; Klein, Dominik; Kessler, Winfried

    2015-11-05

    The olefin ethylene is a ubiquitously found gas. It originates predominantly from plants, combustion processes and industrial sources. In mammals, inhaled ethylene is metabolized by cytochrome P450-dependent monooxygenases, particularly by cytochrome P450 2E1, to ethylene oxide, an epoxide that directly alkylates proteins and DNA. Ethylene oxide was mutagenic in vitro and in vivo in insects and mammals and carcinogenic in rats and mice. A physiological toxicokinetic model is a most useful tool for estimating the ethylene oxide burden in ethylene-exposed rodents and humans. The only published physiological toxicokinetic model for ethylene and metabolically produced ethylene oxide is discussed. Additionally, existing data required for the development of a future model and for testing its predictive accuracy are reviewed and extended by new gas uptake studies with ethylene and ethylene oxide in B6C3F1 mice and with ethylene in F344 rats. Copyright © 2015 The Authors. Published by Elsevier Ireland Ltd.. All rights reserved.

  6. Selective oxidation of methane to ethane and ethylene over various oxide catalysts

    NARCIS (Netherlands)

    Roos, J.A.; Bakker, A.G.; Bosch, H.; van Ommen, J.G.; Ross, J.R.H.

    1987-01-01

    Preliminary results are reported for the oxidative coupling of methane to give ethane/ethylene mixtures over a series of different catalyst formulations; the temperature range studied is 650–850°C. A comparison is made of the behaviour of lead/alumina and lithium/magnesia materials. It is found that

  7. 78 FR 44117 - Notice of a Public Comment Period on the Draft IRIS Carcinogenicity Assessment for Ethylene Oxide

    Science.gov (United States)

    2013-07-23

    ... Public Comment Period on the Draft IRIS Carcinogenicity Assessment for Ethylene Oxide AGENCY... Carcinogenicity of Ethylene Oxide'' (EPA/635/R-13/128a) and on the draft peer review charge questions. The draft... on the draft Evaluation of the Inhalation Carcinogenicity of Ethylene Oxide and on the draft peer...

  8. Kinetic studies of potassium permanganate adsorption by activated carbon and its ability as ethylene oxidation material

    Science.gov (United States)

    Aprilliani, F.; Warsiki, E.; Iskandar, A.

    2018-03-01

    Generally, ethylene production in many horticultural products has been seen to be detrimental to the quality during storage and distribution process. For this reason, removing ethylene from storage or distribution atmosphere is needed to maintain the quality. One of the technologies that can be applied is the use of potassium permanganate (KMnO4). KMnO4 is an active compound that can be used as an oxidizing agent on ethylene removal process. KMnO4 is not recommended for direct used application. As the result, additional material is required to impregnate the potassium permanganate. The inert materials used are commercial activated carbon. Activated carbon is chosen because it has high surface area. The purpose of this research is to determine kinetics adsorption and oxidation model of ethylene removal material. The kinetics adsorption was determined using the pseudo-first and second-order kinetic models. The data on adsorption process show that the second-order equation is more suitable to express the adsorption process on this research. The analyzing of the ethylene oxidation capacity increased with time until it reaches an optimal value. The ethylene oxidation rate is able to be estimated by the formula r = 0.1967 [C2H4]0.99 [KMnO4]0.01; MSE = 0.44 %. The actual and estimation data of ethylene oxidation show that the model is fitted to describe the actual ethylene oxidation under same experimental conditions.

  9. Effect of poly(ethylene oxide) homopolymer and two different poly(ethylene oxide-b-poly(propylene oxide)-b-poly(ethylene oxide) triblock copolymers on morphological, optical, and mechanical properties of nanostructured unsaturated polyester.

    Science.gov (United States)

    Builes, Daniel H; Hernández-Ortiz, Juan P; Corcuera, Ma Angeles; Mondragon, Iñaki; Tercjak, Agnieszka

    2014-01-22

    Novel nanostructured unsaturated polyester resin-based thermosets, modified with poly(ethylene oxide) (PEO), poly(propylene oxide) (PPO), and two poly(ethylene oxide-b-propylene oxide-b-ethylene oxide) block copolymers (BCP), were developed and analyzed. The effects of molecular weights, blocks ratio, and curing temperatures on the final morphological, optical, and mechanical properties were reported. The block influence on the BCP miscibility was studied through uncured and cured mixtures of unsaturated polyester (UP) resins with PEO and PPO homopolymers having molecular weights similar to molecular weights of the blocks of BCP. The final morphology of the nanostructured thermosetting systems, containing BCP or homopolymers, was investigated, and multiple mechanisms of nanostructuration were listed and explained. By considering the miscibility of each block before and after curing, it was determined that the formation of the nanostructured matrices followed a self-assembly mechanism or a polymerization-induced phase separation mechanism. The miscibility between PEO or PPO blocks with one of two phases of UP matrix was highlighted due to its importance in the final thermoset properties. Relationships between the final morphology and thermoset optical and mechanical properties were examined. The mechanisms and physics behind the morphologies lead toward the design of highly transparent, nanostructured, and toughened thermosetting UP systems.

  10. Oxidative dehydrogenation of ethane to ethylene using vanadia based catalysts

    Energy Technology Data Exchange (ETDEWEB)

    Qiao, Ailing; Kalevaru, V.N. [Univ. Rostock e.V., Rostock (Germany). Leibniz-Inst. fuer Katalyse; Humar, A.S.; Lingaiah, N.; Sai Prasad, P.S.; Martin, A. [Indian Institute of Chemical Technology, Hyderabad (India). Inorganic and Physical Chemistry Div.

    2011-07-01

    In this work, we describe the application of V{sub 2}O{sub 5}/Nb{sub 2}O{sub 5} catalysts for the oxidative dehydrogenation (ODH) of ethane to ethylene. A series of Nb{sub 2}O{sub 5} supported V{sub 2}O{sub 5} catalysts were prepared by impregnation technique. NH{sub 4}VO{sub 3} was used as a precursor for V{sub 2}O{sub 5}. The content of V{sub 2}O{sub 5} is varied in the range from 5 to 20 wt%. Catalytic tests were carried out in a fixed bed quartz reactor in the temperature range from 500 to 600 C. The conversion of ethane has been increased from ca. 20 to 35 % with increase in temperature from 500 to 600 C, while the yield of ethylene is increased from about 5 to 12 % only. CO and CO{sub 2} are the only major by-products of the reaction. The activity tests were performed at low O{sub 2} concentration in the feed and hence low conversions were achieved. Furthermore, the conversion of ethane is found to increase continuously with increase in V{sub 2}O{sub 5} loading while the yield of C{sub 2}H{sub 4} increased only up to 10wt% V{sub 2}O{sub 5} and then decreased. Results revealed that the catalytic activity and selectivity is found to depend on the V{sub 2}O{sub 5} loading. Among all, 10wt% V{sub 2}O{sub 5}/Nb{sub 2}O{sub 5} catalyst has displayed the superior performance. (orig.)

  11. Ethylene Gas Sensing Properties of Tin Oxide Nanowires Synthesized via CVD Method

    Science.gov (United States)

    Akhir, Maisara A. M.; Mohamed, Khairudin; Rezan, Sheikh A.; Arafat, M. M.; Haseeb, A. S. M. A.; Uda, M. N. A.; Nuradibah, M. A.

    2018-03-01

    This paper studies ethylene gas sensing performance of tin oxide (SnO2) nanowires (NWs) as sensing material synthesized using chemical vapor deposition (CVD) technique. The effect of NWs diameter on ethylene gas sensing characteristics were investigated. SnO2 NWs with diameter of ∼40 and ∼240 nm were deposited onto the alumina substrate with printed gold electrodes and tested for sensing characteristic toward ethylene gas. From the finding, the smallest diameter of NWs (42 nm) exhibit fast response and recovery time and higher sensitivity compared to largest diameter of NWs (∼240 nm). Both sensor show good reversibility features for ethylene gas sensor.

  12. Metal oxides modified NiO catalysts for oxidative dehydrogenation of ethane to ethylene

    KAUST Repository

    Zhu, Haibo

    2014-06-01

    The sol-gel method was applied to the synthesis of Zr, Ti, Mo, W, and V modified NiO based catalysts for the ethane oxidative dehydrogenation reaction. The synthesized catalysts were characterized by XRD, N2 adsorption, SEM and TPR techniques. The results showed that the doping metals could be highly dispersed into NiO domains without the formation of large amount of other bulk metal oxide. The modified NiO materials have small particle size, larger surface area, and higher reduction temperature in contrast to pure NiO. The introduction of group IV, V and VI transition metals into NiO decreases the catalytic activity in ethane ODH. However, the ethylene selectivity is enhanced with the highest level for the Ni-W-O and Ni-Ti-O catalysts. As a result, these two catalysts show improved efficiency of ethylene production in the ethane ODH reaction. © 2014 Elsevier B.V. All rights reserved.

  13. Ethylene signalling is mediating the early cadmium-induced oxidative challenge in Arabidopsis thaliana.

    Science.gov (United States)

    Schellingen, Kerim; Van Der Straeten, Dominique; Remans, Tony; Vangronsveld, Jaco; Keunen, Els; Cuypers, Ann

    2015-10-01

    Cadmium (Cd) induces the generation of reactive oxygen species (ROS) and stimulates ethylene biosynthesis. The phytohormone ethylene is a regulator of many developmental and physiological plant processes as well as stress responses. Previous research indicated various links between ethylene signalling and oxidative stress. Our results support a correlation between the Cd-induced oxidative challenge and ethylene signalling in Arabidopsis thaliana leaves. The effects of 24 or 72 h exposure to 5 μM Cd on plant growth and several oxidative stress-related parameters were compared between wild-type (WT) and ethylene insensitive mutants (etr1-1, ein2-1, ein3-1). Cadmium-induced responses observed in WT plants were mainly affected in etr1-1 and ein2-1 mutants, of which the growth was less inhibited by Cd exposure as compared to WT and ein3-1 mutants. Both etr1-1 and ein2-1 showed a delayed response in the glutathione (GSH) metabolism, including GSH levels and transcript levels of GSH synthesising and recycling enzymes. Furthermore, the expression of different oxidative stress marker genes was significantly lower in Cd-exposed ein2-1 mutants, evidencing that ethylene signalling is involved in early responses to Cd stress. A model for the cross-talk between ethylene signalling and oxidative stress is proposed. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.

  14. Effects of Lytic Polysaccharide Monooxygenase Oxidation on Cellulose Structure and Binding of Oxidized Cellulose Oligomers to Cellulases

    Energy Technology Data Exchange (ETDEWEB)

    Vermaas, Josh V.; Crowley, Michael F.; Beckham, Gregg T.; Payne, Christina M.

    2015-05-21

    with different affinities relative to cellobiose itself, which potentially affects hydrolytic turnover through product inhibition. To examine the effect of oxidation on cello-oligomer binding, we use thermodynamic integration to compute the relative change in binding free energy between the hydrolyzed and oxidized products in the active site of Family 7 and Family 6 processive glycoside hydrolases, Trichoderma reesei Cel7A and Cel6A, which are key industrial cellulases and commonly used model systems for fungal cellulases. Our results suggest that the equilibrium between the two reducing end oxidized products, favoring the linear aldonic acid, may increase product inhibition, which would in turn reduce processive substrate turnover. In the case of LMPO action at the nonreducing end, oxidation appears to lower affinity with the nonreducing end specific cellulase, reducing product inhibition and potentially promoting processive cellulose turnover. Overall, this suggests that oxidation of recalcitrant polysaccharides by LPMOs accelerates degradation not only by increasing the concentration of chain termini but also by reducing decrystallization work, and that product inhibition may be somewhat reduced as a result.

  15. Antibacterial effects of electrospun chitosan/poly(ethylene oxide) nanofibrous membranes loaded with chlorhexidine and silver

    NARCIS (Netherlands)

    Song, J.; Remmers, S.J.; Shao, J.; Kolwijck, E.; Walboomers, X.F.; Jansen, J.A.; Leeuwenburgh, S.C.; Yang, F.

    2016-01-01

    To prevent percutaneous device associated infections (PDAIs), we prepared electrospun chitosan/poly(ethylene oxide) (PEO) nanofibrous membrane containing silver nanoparticles as an implantable delivery vehicle for the dual release of chlorhexidine and silver ions. We observed that the silver

  16. Ethylene Oxide Commerical Sterilization and Fumigation Operations National Emission Standards for Hazardous Air Pollutants (NESHAP)

    Science.gov (United States)

    The purpose of this document is to provide implementation materials to assist in conducting complete and efficient inspections at ethylene oxide commercial sterilization and fumigation operations to determine compliance with the NESHAP

  17. Ethylene Oxide Emissions Standards for Sterilization Facilities: National Emission Standards for Hazardous Air Pollutants (NESHAP)

    Science.gov (United States)

    Learn about the NESHAP for ethylene oxide emissions for sterilization facilities. Find the rule history information, federal register citations, legal authority, and related rules as well as a rule summary.

  18. A mechanistic investigation of ethylene oxide hydrolysis to ethanediol.

    Science.gov (United States)

    Lundin, Angelica; Panas, Itai; Ahlberg, Elisabet

    2007-09-20

    The B3LYP/6-311+G(d,p) description is employed to study the heterolytic ring opening mechanisms under microsolvation conditions for ethylene oxide in acidic, neutral, and alkaline environments. In acid and alkaline media, a concerted trans S(N)2 reaction is strongly favored as compared to the corresponding cis reaction. The importance of the nucleophile, water in acidic media and hydroxide ion in alkaline media, for lowering the activation enthalpy is emphasized and activation energies of approximately 80 and approximately 60 kJ mol(-1) are obtained under acid and alkaline conditions, respectively. Under neutral conditions, the trans S(N)2 mechanism becomes inaccessible because it invokes the formation of a transient H+ and OH- pair across the 1,2-ethanediol molecule. Rather, epoxide ring opening is achieved by hydrolysis of a single water molecule. The latter mechanism displays significantly greater activation enthalpy (205 kJ mol(-1)) than those in acid and alkaline environments. This is in agreement with experiment. Product distributions of simple olefins in neutral aqueous media, as well as the detrimental impact of acid/base conditions for the selectivity of epoxidation catalysts in aqueous media, are discussed.

  19. Chemical modifications of therapeutic proteins induced by residual ethylene oxide.

    Science.gov (United States)

    Chen, Louise; Sloey, Christopher; Zhang, Zhongqi; Bondarenko, Pavel V; Kim, Hyojin; Ren, Da; Kanapuram, Sekhar

    2015-02-01

    Ethylene oxide (EtO) is widely used in sterilization of drug product primary containers and medical devices. The impact of residual EtO on protein therapeutics is of significant interest in the biopharmaceutical industry. The potential for EtO to modify individual amino acids in proteins has been previously reported. However, specific identification of EtO adducts in proteins and the effect of residual EtO on the stability of therapeutic proteins has not been reported to date. This paper describes studies of residual EtO with two therapeutic proteins, a PEGylated form of the recombinant human granulocyte colony-stimulating factor (Peg-GCSF) and recombinant human erythropoietin (EPO) formulated with human serum albumin (HSA). Peg-GCSF was filled in an EtO sterilized delivery device and incubated at accelerated stress conditions. Glu-C peptide mapping and LC-MS analyses revealed residual EtO reacted with Peg-GCSF and resulted in EtO modifications at two methionine residues (Met-127 and Met-138). In addition, tryptic peptide mapping and LC-MS analyses revealed residual EtO in plastic vials reacted with HSA in EPO formulation at Met-328 and Cys-34. This paper details the work conducted to understand the effects of residual EtO on the chemical stability of protein therapeutics. © 2014 Wiley Periodicals, Inc. and the American Pharmacists Association.

  20. Synthesis and Functionalization of Poly(ethylene oxide-b-ethyloxazoline) Diblock Copolymers with Phosphonate Ions

    OpenAIRE

    Chen, Alfred Yuen-Wei

    2013-01-01

    Poly(ethylene oxide) (PEO) and poly(2-ethyl-2-oxazoline) (PEOX) are biocompatible polymers that act as hydrophilic "stealth" drug carriers. As block copolymers, the PEOX group offers a wider variety of functionalization. The goal of this project was to synthesize a poly(ethylene oxide)-b-poly(2-ethyl-2-oxazoline) (PEO-b-PEOX) block copolymer and functionalize pendent groups of PEOX with phosphonic acid. This was achieved through cationic ring opening polymerization (CROP) of 2-...

  1. Rutin improves spatial memory in Alzheimer's disease transgenic mice by reducing Aβ oligomer level and attenuating oxidative stress and neuroinflammation.

    Science.gov (United States)

    Xu, Peng-Xin; Wang, Shao-Wei; Yu, Xiao-Lin; Su, Ya-Jing; Wang, Teng; Zhou, Wei-Wei; Zhang, He; Wang, Yu-Jiong; Liu, Rui-Tian

    2014-05-01

    Alzheimer's disease (AD) is a progressive, neurodegenerative disease characterized by extracellular β-amyloid (Aβ) plaques and intracellular neurofibrillary tangles in the brain. Aβ aggregation is closely associated with neurotoxicity, oxidative stress, and neuronal inflammation. The soluble Aβ oligomers are believed to be the most neurotoxic form among all forms of Aβ aggregates. We have previously reported a polyphenol compound rutin that could inhibit Aβ aggregation and cytotoxicity, attenuate oxidative stress, and decrease the production of nitric oxide and proinflammatory cytokines in vitro. In the current study, we investigated the effect of rutin on APPswe/PS1dE9 transgenic mice. Results demonstrated that orally administered rutin significantly attenuated memory deficits in AD transgenic mice, decreased oligomeric Aβ level, increased super oxide dismutase (SOD) activity and glutathione (GSH)/glutathione disulfide (GSSG) ratio, reduced GSSG and malondialdehyde (MDA) levels, downregulated microgliosis and astrocytosis, and decreased interleukin (IL)-1β and IL-6 levels in the brain. These results indicated that rutin is a promising agent for AD treatment because of its antioxidant, anti-inflammatory, and reducing Aβ oligomer activities. Copyright © 2014 Elsevier B.V. All rights reserved.

  2. Effect of ethylene oxide sterilization on the osteoinductivity of demineralized allograft bone powder

    International Nuclear Information System (INIS)

    Hamid Reza Aghayan; Babak Arjmand; Mehdi Golestani; Farokh Tirgari

    2008-01-01

    Full text: Ethylene oxide has been widely used for secondary sterilization of bone allograft to reduce the risk of infection and associated complications. In this study we investigate the effects of ethylene oxide gas sterilization on the osteoinductivity of demineralized bone Powder. Eighteen rats received two separate implants consisting of 30 mg aseptically prepared and 30 mg ethylene oxide-sterilized demineralized bone powder. The demineralized bone powder from each group was placed into two separate muscle pouch created in the paravertebral muscles of each rat. After 4 weeks each implantation site was removed with 0.5 cm normal tissue around the implant. Histological examination was done to determine the presence or absence of osteoinduction. All except one of eighteen aseptically prepared demineralized bone powder sites histologically contained new bone elements (94.4%) and fourteen (77.7%) of ethylene oxide sterilized demineralized bone powder sites showed evidence of new bone elements (p>0.05). There is no significant difference in osteoblast formation in two groups. We concluded that ethylene oxide sterilization in 42 degree C did not significantly reduce the osteoinductivity of demineralized bone powder. So ethylene oxide can be considered as a suitable but not perfect method for secondary sterilization of demineralized bone powder. (Author)

  3. Ni–Ta–O mixed oxide catalysts for the low temperature oxidative dehydrogenation of ethane to ethylene

    KAUST Repository

    Zhu, Haibo; Rosenfeld, Devon C.; Anjum, Dalaver H.; Sangaru, Shiv; Saih, Youssef; Ould-Chikh, Samy; Basset, Jean-Marie

    2015-01-01

    The "wet" sol-gel and "dry" solid-state methods were used to prepare Ni-Ta-O mixed oxide catalysts. The resulting Ni-Ta oxides exhibit high activity and selectivity for the low temperature oxidative dehydrogenation of ethane to ethylene. The Ta

  4. Low-Energy, Low-Cost Production of Ethylene by Low- Temperature Oxidative Coupling of Methane

    Energy Technology Data Exchange (ETDEWEB)

    Radaelli, Guido [Siluria Technologies, Inc., San Francisco, CA (United States); Chachra, Gaurav [Siluria Technologies, Inc., San Francisco, CA (United States); Jonnavittula, Divya [Siluria Technologies, Inc., San Francisco, CA (United States)

    2017-12-30

    In this project, we develop a catalytic process technology for distributed small-scale production of ethylene by oxidative coupling of methane at low temperatures using an advanced catalyst. The Low Temperature Oxidative Coupling of Methane (LT-OCM) catalyst system is enabled by a novel chemical catalyst and process pioneered by Siluria, at private expense, over the last six years. Herein, we develop the LT-OCM catalyst system for distributed small-scale production of ethylene by identifying and addressing necessary process schemes, unit operations and process parameters that limit the economic viability and mass penetration of this technology to manufacture ethylene at small-scales. The output of this program is process concepts for small-scale LT-OCM catalyst based ethylene production, lab-scale verification of the novel unit operations adopted in the proposed concept, and an analysis to validate the feasibility of the proposed concepts.

  5. Effect of acid on the aggregation of poly(ethylene xide)-poly(propylene oxide)-poly(ethylene oxide) block copolymers.

    Science.gov (United States)

    Yang, Bin; Guo, Chen; Chen, Shu; Ma, Junhe; Wang, Jing; Liang, Xiangfeng; Zheng, Lily; Liu, Huizhou

    2006-11-23

    The acid effect on the aggregation of poly(ethylene oxide)-poly(propylene oxide)-poly(ethylene oxide) block copolymers EO(20)PO(70)EO(20) has been investigated by transmission electron microscopy (TEM), particle size analyzer (PSA), Fourier transformed infrared, and fluorescence spectroscopy. The critical micellization temperature for Pluronic P123 in different HCl aqueous solutions increases with the increase of acid concentration. Additionally, the hydrolysis degradation of PEO blocks is observed in strong acid concentrations at higher temperatures. When the acid concentration is low, TEM and PSA show the increase of the micelle mean diameter and the decrease of the micelle polydispersity at room temperature, which demonstrate the extension of EO corona and tendency of uniform micelle size because of the charge repulsion. When under strong acid conditions, the aggregation of micelles through the protonated water bridges was observed.

  6. Ion-molecule reactions in the binary mixture of ethylene oxide and trioxane, 2

    International Nuclear Information System (INIS)

    Kumakura, Minoru; Arakawa, Kazuo; Sugiura, Toshio.

    1978-01-01

    The ion-molecule reactions in the binary mixture of ethylene oxide and trioxane have been studied with use of a modified time-of-flight mass spectrometer. As cross-reaction product ions, C 3 H 5 O 2 + , C 3 H 6 O 2 +sup(, and C**3**H**7**O**2**)+sup( were observed under the conditions of long delay times and elevated pressure. It was found that these ions are formed by the dissociation of unstable intermediate-complex resulting from the reaction of ethylene oxide molecular ion with trioxane. It was proposed that the complex is of cyclic structure in which positive charge is delocalized. From the consideration of isotopic distribution of the product ions in ethylene-d**4** oxide-trioxane mixtures, the skeletal structures of the product ions were investigated. The rate constants of the formation reactions of C**3**H**5**O**2**)+sup(, C**3**H**6**O**2**)+sup(, and C**3**H**7**O**2**)+sup( in ethylene oxide-trioxane mixtures were found to be 2.20 x 10)-10sup(, 2.61 x 10)-10sup(, and 1.74 x 10)-10sup( cm)3sup( molecule)-1sup(s)-1 , respectively. (auth.)

  7. Recycling Monoethylene Glycol (MEG from the Recirculating Waste of an Ethylene Oxide Unit

    Directory of Open Access Journals (Sweden)

    Moayed Mohsen

    2017-06-01

    Full Text Available In the ethylene glycol generation unit of petrochemical plants, first a reaction of ethylene oxide takes place which is then followed by other side reactions. These reactions include water absorption with ethylene oxide, which leads to the generation of formaldehyde and acetaldehyde. Over the lifetime of the alpha-alumina-based silver catalyst there is an increase in side reactions, increasing the amount of the formaldehyde and acetaldehyde generated by the ethylene oxide reactor which leads to reduced MEG product purity. Given the need of a petrochemical complex to further strip the aldehyde (formaldehyde and acetaldehyde to increase the quality of the MEG and increase the lifetime of the alpha-alumina-based silver catalyst, resin beds are designed and their surface absorption capacity is investigated to optimize aldehyde (formaldehyde and acetaldehyde removal in the recirculating water flow of the ethylene oxide unit. Experiments show that the ion exchange system based on strong anionic resin pre-treated with a sodium bisulfite solution can reduce the aldehyde level from about 300ppm to less than 5ppm. After the resin is saturated with aldehyde, the resin can be recycled using the sodium bisulfite solution which is a cheap chemical substance.

  8. Comparative analysis of spices decontaminated by ethylene oxide or gamma radiation

    International Nuclear Information System (INIS)

    Farkas, J.; Andrassy, E.

    1988-01-01

    A comparison was made between the microbiological efficacy of ethylene oxide treatment (800 g T gas per m 3 at 22 deg C for 6 h) and irradiation with 4 or 8 kGy gamma radiation and between their respective effects on the volatile oil content of black pepper, the sensory characteristics of ground black pepper, ground paprika, onion powder and garlic powder and the water uptake of the latter two seasonings. The study showed radiation treatment to be competitive with ethylene oxide treatment from the point of view of microbiological efficacy as well as in maintaining the quality characteristics of seasoning. (author) 53 refs.; 7 figs.; 3 tabs

  9. Quantitative comparisons of genotoxic effects of atomic energy and fossil-fuelled energy. Rad-equivalences for ethylene, ethylene oxide and formaldehyde - consequences for decisions at Government level

    International Nuclear Information System (INIS)

    Latarjet, R.; Averbeck, D.; Levy, S.; Poirier, V.

    1982-01-01

    Rad-equivalences have been determined on the basis of data on the genotoxic effects of low linear energy transfer ionizing radiation and of three chemical pollutants - ethylene, ethylene oxide and formaldehyde - emitted from energy-producing power plants. In the case of ethylene and its metabolite, ethylene oxide, the conditions were particularly favourable because the equivalences could be based on the induction of total mutations in the mouse, which is the same genetic end-point used for the assessment of radiation risks. Once established, the rad-equivalences were used (a) to extrapolate the rules adopted for radiation to each of these two compounds and (b) to make recommendations for exposed workers at 'hot spots' and for the general population. Measurements of ethylene in power plants and in the atmosphere of Paris have indicated that in most cases the measured values fall within the recommended values. However, pollution by ethylene oxide in cold sterilization units should be reduced. Rad-equivalences obtained for lethal effects, and for the induction of chromosome aberrations by formaldehyde in human cells in vitro, suggest that the maximum admissible concentrations are far too high in most countries and must be reconsidered. In France, the Ministry of Health is taking the rad-equivalences into consideration for the preparation of a law regulating pollution by ethylene and ethylene oxide - as a first step. These results show that rad-equivalences can be used for risk assessments of genotoxic effects from power plants and that decisions can be made by extrapolating the rules adopted for radiation protection to some chemical mutagens, when certain strict conditions are fulfilled. (author)

  10. Gas-permeation properties of poly(ethylene oxide) poly(butylene terephthalate block copolymers

    NARCIS (Netherlands)

    Metz, S.J.; Mulder, M.H.V.; Wessling, Matthias

    2004-01-01

    This paper reports the gas-permeation properties of poly(ethylene oxide) (PEO) poly(butylene terephthalate) (PBT) segmented multiblock copolymers. These block copolymers allow a precise structural modification by the amount of PBT and the PEO segment length, enabling a systematic study of the

  11. CO2 permeation properties of poly(ethylene oxide)-based segmented block copolymers

    NARCIS (Netherlands)

    Husken, D.; Visser, Tymen; Wessling, Matthias; Gaymans, R.J.

    2010-01-01

    This paper discusses the gas permeation properties of poly(ethylene oxide) (PEO)-based segmented block copolymers containing monodisperse amide segments. These monodisperse segments give rise to a well phase-separated morphology, comprising a continuous PEO phase with dispersed crystallised amide

  12. On the structure of polymeric composite of metallacarborane with poly(ethylene oxide)

    Czech Academy of Sciences Publication Activity Database

    Matějíček, P.; Brus, Jiří; Jigounov, Alexander; Pleštil, Josef; Uchman, M.; Procházka, K.; Gradzielski, M.

    2011-01-01

    Roč. 44, č. 10 (2011), s. 3847-3855 ISSN 0024-9297 R&D Projects: GA MŠk 2B08021 Institutional research plan: CEZ:AV0Z40500505 Keywords : polymer * metallacarborane * poly(ethylene oxide) Subject RIV: CB - Analytical Chemistry, Separation Impact factor: 5.167, year: 2011

  13. Ripening, storage temperature, ethylene action, and oxidative stress alter apple peel phytosterol metabolism

    Science.gov (United States)

    The chilling conditions of apple cold storage can provoke an economically significant necrotic peel disorder called superficial scald (scald) in susceptible cultivars. Disorder development can be reduced by inhibiting ethylene action or oxidative stress. We found previously that scald is preceded b...

  14. Toluidine blue-sodium lauryl ether sulfate complexes : Influence of ethylene oxide length

    NARCIS (Netherlands)

    Vleugels, L.F.W.; Féat, A.; Voets, I.K.; Tuinier, R.

    2017-01-01

    Sodium Lauryl Ether Sulfates (SLES) are an increasingly important and versatile type of surfactants. The complexation between ortho-Toluidine blue (TBO) and a homologous series of SLES, including Sodium Lauryl Sulfate (SDS) without Ethylene Oxide (EO), has been investigated using visible

  15. Synthesis and characterization of polystyrene-poly(ethylene oxide)-heparin block copolymers

    NARCIS (Netherlands)

    Vulić, I.; Okano, T.; Kim, S.W.; Feijen, Jan

    1988-01-01

    A procedure for the preparation of new block copolymers composed of a hydrophobic block of polystyrene, a hydrophilic spacer-block of poly(ethylene oxide) and a bioactive block of heparin was investigated. Polystyrene with one amino group per chain was synthesized by free radical oligomerization of

  16. Improved synthesis of polystyrene-poly(ethylene oxide)-heparin block copolymers

    NARCIS (Netherlands)

    Vulic, I.; Loman, A.J.B.; Feijen, Jan; Okano, T.; Kim, S.W.

    1990-01-01

    A novel procedure for the synthesis of block copolymers composed of a hydrophobic block of polystyrene, a hydrophilic block of poly(ethylene oxide) and a bioactive block of nitrous acid-degraded heparin was developed. Amino-semitelechelic polystyrene was prepared by anionic polymerization of styrene

  17. Electrochemical and density functional studies of the catalytic ethylene oxidation on nanostructured Au electrodes

    Czech Academy of Sciences Publication Activity Database

    Šebera, Jakub; Hoffmannová, Hana; Krtil, Petr; Samec, Zdeněk; Záliš, Stanislav

    2010-01-01

    Roč. 158, 1-2 (2010), s. 29-34 ISSN 0920-5861 R&D Projects: GA AV ČR KAN100400702 Institutional research plan: CEZ:AV0Z40400503 Keywords : electrocatalysis * ethylene oxidation * DFT Subject RIV: CG - Electrochemistry Impact factor: 2.993, year: 2010

  18. Nanofibrous web quality in dependence on the preparation of poly(ethylene oxide) aqueous solutions

    Czech Academy of Sciences Publication Activity Database

    Peer, Petra; Filip, Petr

    2017-01-01

    Roč. 108, č. 12 (2017), s. 2021-2026 ISSN 0040-5000 R&D Projects: GA ČR GA17-26808S Institutional support: RVO:67985874 Keywords : nanofibrous web * poly(ethylene oxide) solution * magnetic stirring * vibrational shaking Subject RIV: BK - Fluid Dynamics OBOR OECD: Polymer science Impact factor: 1.007, year: 2016

  19. Hydrophilic segmented block copolymers based on poly(ethylene oxide) and monodisperse amide segments

    NARCIS (Netherlands)

    Husken, D.; Feijen, Jan; Gaymans, R.J.

    2007-01-01

    Segmented block copolymers based on poly(ethylene oxide) (PEO) flexible segments and monodisperse crystallizable bisester tetra-amide segments were made via a polycondensation reaction. The molecular weight of the PEO segments varied from 600 to 4600 g/mol and a bisester tetra-amide segment (T6T6T)

  20. 40 CFR 721.7000 - Polymer of disodium maleate, allyl ether, and ethylene oxide.

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 30 2010-07-01 2010-07-01 false Polymer of disodium maleate, allyl... New Uses for Specific Chemical Substances § 721.7000 Polymer of disodium maleate, allyl ether, and... substance identified generically as a polymer of disodium maleate, allyl ether, and ethylene oxide (P-91...

  1. Stability and effectiveness against bacterial adhesion of poly(ethylene oxide) coatings in biological fluids

    NARCIS (Netherlands)

    Roosjen, Astrid; de Vries, Jacob; van der Mei, HC; Norde, W; Busscher, HJ

    Poly(ethylene oxide) (PEO) coatings have been shown to reduce the adhesion of different microbial strains and species and thus are promising as coatings to prevent biomaterial-centered infection of medical implants. Clinically, however, PEO coatings are not yet applied, as little is known about

  2. Synthesis of Monodispersed Tantalum(V) oxide Nanospheres by an Ethylene Glycol Mediated Route

    Science.gov (United States)

    Tantalum(V) oxide (Ta2O5) nanospheres have been synthesized by a very simple ethylene glycol mediated route. The two-step process involves the formation of glycolate nanoparticles and their subsequent hydrolysis and calcination to generate the final Ta2O5 nanospheres. The synthes...

  3. Stability and effectiveness against bacterial adhesion of poly(ethylene oxide) coatings in biological fluids

    NARCIS (Netherlands)

    Roosjen, A.; Vries, de J.; Mei, van der H.C.; Norde, W.; Busscher, H.J.

    2005-01-01

    Poly(ethylene oxide) (PEO) coatings have been shown to reduce the adhesion of different microbial strains and species and thus are promising as coatings to prevent biomaterial-centered infection of medical implants. Clinically, however, PEO coatings are not yet applied, as little is known about

  4. Crystallization and unusual rheological behavior in poly(ethylene oxide)–clay nanocomposites

    KAUST Repository

    Kelarakis, Antonios; Giannelis, Emmanuel P.

    2011-01-01

    We report a systematic study of the crystallization and rheological behavior of poly(ethylene oxide) (PEO)-clay nanocomposites. To that end a series of nanocomposites based on PEOs of different molecular weight (103 < MW < 105 g/mol) and clay

  5. Characterization of Titanium Oxide Nanoparticles Obtained by Hydrolysis Reaction of Ethylene Glycol Solution of Alkoxide

    International Nuclear Information System (INIS)

    Uekawa, N.; Endo, N.; Ishii, K.; Kojima, T.; Kakegawa, K.

    2012-01-01

    Transparent and stable sols of titanium oxide nanoparticles were obtained by heating a mixture of ethylene glycol solution of titanium tetraisopropoxide (TIP) and a NH 3 aqueous solution at 368 K for 24 h. The concentration of NH 3 aqueous solution affected the structure of the obtained titanium oxide nanoparticles. For NH 3 aqueous solution concentrations higher than 0.2 mol/L, a mixture of anatase TiO 2 nanoparticles and layered titanic acid nanoparticles was obtained. The obtained sol was very stable without formation of aggregated precipitates and gels. Coordination of ethylene glycol to Ti4+ ions inhibited the rapid hydrolysis reaction and aggregation of the obtained nanoparticles. The obtained titanium oxide nanoparticles had a large specific surface area: larger than 350 m2/g. The obtained titanium oxide nanoparticles showed an enhanced adsorption towards the cationic dye molecules. The selective adsorption corresponded to presence of layered titanic acid on the obtained anatase TiO 2 nanoparticles.

  6. Solubilization of docetaxel in poly(ethylene oxide)-block-poly(butylene/styrene oxide) micelles.

    Science.gov (United States)

    Elsabahy, Mahmoud; Perron, Marie-Eve; Bertrand, Nicolas; Yu, Ga-Er; Leroux, Jean-Christophe

    2007-07-01

    Poly(ethylene oxide)-block-poly(styrene oxide) (PEO-b-PSO) and PEO-b-poly(butylene oxide) (PEO-b-PBO) of different chain lengths were synthesized and characterized for their self-assembling properties in water by dynamic/static light scattering, spectrofluorimetry, and transmission electron microscopy. The resulting polymeric micelles were evaluated for their ability to solubilize and protect the anticancer drug docetaxel (DCTX) from degradation. The drug release kinetics as well as the cytotoxicity of the loaded micelles were assessed in vitro. All polymers formed micelles with a highly viscous core at low critical association concentrations (hydrolysis under accelerated stability testing conditions. Only PEO-b-PBO bearing 24 BO units afforded significant protection against degradation. In vitro, DCTX was released slower from the latter micelles, but all formulations possessed a similar cytotoxic effect against PC-3 prostate cancer cells. These data suggest that PEO-b-P(SO/BO) micelles could be used as alternatives to conventional surfactants for the solubilization of taxanes.

  7. Oxygen Barrier Properties and Melt Crystallization Behavior of Poly(ethylene terephthalate)/Graphene Oxide Nanocomposites

    OpenAIRE

    Szymczyk, Anna; Paszkiewicz, Sandra; Pawelec, Iwona; Lisiecki, Slawomir; Jotko, Marek; Spitalsky, Zdenko; Mosnácek, Jaroslav; Roslaniec, Zbigniew

    2015-01-01

    Poly(ethylene terephthalate) nanocomposites with low loading (0.1–0.5 wt%) of graphene oxide (GO) have been prepared by using in situ polymerization method. TEM study of nanocomposites morphology has shown uniform distribution of highly exfoliated graphene oxide nanoplatelets in PET matrix. Investigations of oxygen permeability of amorphous films of nanocomposites showed that the nanocomposites had better oxygen barrier properties than the neat PET. The improvement of oxygen permeability for ...

  8. Electrical and mechanical properties of poly(ethylene oxide)/intercalated clay polymer electrolyte

    International Nuclear Information System (INIS)

    Moreno, Mabel; Quijada, Raúl; Santa Ana, María A.; Benavente, Eglantina; Gomez-Romero, Pedro; González, Guillermo

    2011-01-01

    Highlights: ► Poly(ethylene oxide)/intercalated clay nanocomposite as filler in solid poly(ethylene oxide) electrolytes. ► Nanocomposite filler improves mechanical properties, transparency, and conductivity of poly(ethylene oxide) electrolyte films. ► Nanocomposite is more effective than unmodified clay in improving polymer electrolyte properties. ► Low Li/polymer ratio avoids crystalline Li complexes, so effects mainly arise from the polymer. ► High nanocomposite/poly(ethylene oxide)-matrix affinity enhances microhomogeneity in the polyelectrolyte. - Abstract: Solvent-free solid polymer electrolytes (SPEs) based on two different poly(ethylene oxide), PEO Mw 600,000 and 4,000,000 and intercalated clays are reported. The inorganic additives used were lithiated bentonite and the nanocomposite PEO-bentonite with the same polymer used as matrix. SPE films, obtained in the scale of grams by mixing the components in a Brabender-type batch mixer and molding at 130 °C, were characterized by X-ray diffraction analysis, UV–vis spectroscopy, and thermal analysis. During the preparation of the films, the unmodified clay got intercalated in situ. Comparative analysis of ionic conductivity and mechanical properties of the films show that the conductivity increases with the inclusion of fillers, especially for the polymer with low molecular weight. This effect is more pronounced when using PEO-bentonite as additive. Under selected work conditions, avoiding the presence of crystalline lithium complexes, observed effects are mainly centered on the polymer. An explanation, considering the higher affinity between the modified clay and PEO matrix which leads to differences in the micro homogeneity degree between both types of polymer electrolytes is proposed.

  9. Ethylene, nitric oxide and haemoglobins in plant tolerance to flooding

    DEFF Research Database (Denmark)

    Mur, Luis A J; Gupta, Kapuganti J; Chakraborty, U

    2015-01-01

    As much as 12% of the world's soils may suffer excess water so that flooding is a major limiting factor on crop production in many areas. Plants attempt to deal with submergence by forming root aerenchyma to facilitate oxygen diffusion from the shoot to the root, initiating a hyponastic response...... where petiole elongation facilitates access to atmospheric oxygen or initiating a bio-energetically conserving quiescence phase. Ethylene has well established roles in the initiation of programmed cell death (PCD) to form air-spaces in aerenchyma and in the hyponastic responses in petioles. The flooding...... response. NO is formed from the reduction of NO3/NO2 via several pathways, which are differentially utilized depending on the availability of O2. In fact, NO production and responses to flooding can be directly dependent on the nitrogen status of soil, which reflects local agricultural practice...

  10. Synthesis of novel bis(perfluorophenyl azides) coupling agents: Evaluation of their performance by crosslinking of poly(ethylene oxide)

    KAUST Repository

    Mehenni, Hakim

    2011-11-01

    Novel bis(perfluorophenyl azides) coupling agents, containing spacer arms from ethylene or ethylene glycol subunits, were successfully synthesized. Nitrenes photogenerated from these novel bis(PFPA) coupling agents were applied successfully to the cross-linking of poly(ethylene oxide) (PEO10,000) in either aqueous medium or at the solid state, thus, we demonstrated the potential of these bis(PFPA) molecules as promising coupling agents in surface engineering. © 2011 Elsevier Ltd. All rights reserved.

  11. Differential substrate behaviours of ethylene oxide and propylene oxide towards human glutathione transferase theta hGSTT1-1.

    Science.gov (United States)

    Thier, R; Wiebel, F A; Bolt, H M

    1999-11-01

    The transformation of ethylene oxide (EO), propylene oxide (PO) and 1-butylene oxide (1-BuO) by human glutathione transferase theta (hGSTT1-1) was studied comparatively using 'conjugator' (GSTT1 + individuals) erythrocyte lysates. The relative sequence of velocity of enzymic transformation was PO > EO > 1-BuO. The faster transformation of PO compared to EO was corroborated in studies with human and rat GSTT1-1 (hGSTT1-1 and rGSTT1-1, respectively) expressed by Salmonella typhimurium TA1535. This sequence of reactivities of homologous epoxides towards GSTT1-1 contrasts to the sequence observed in homologous alkyl halides (methyl bromide, MBr; ethyl bromide, EtBr; n-propyl bromide, PrBr) where the relative sequence MeBr > EtBr > PrBr is observed. The higher reactivity towards GSTT1-1 of propylene oxide compared to ethylene oxide is consistent with a higher chemical reactivity. This is corroborated by experimental data of acid-catalysed hydrolysis of a number of aliphatic epoxides, including ethylene oxide and propylene oxide and consistent with semi-empirical molecular orbital modelings.

  12. ABA crosstalk with ethylene and nitric oxide in seed dormancy and germination

    Directory of Open Access Journals (Sweden)

    Erwann eArc

    2013-03-01

    Full Text Available Dormancy is an adaptive trait that enables seed germination to coincide with favorable environmental conditions. It has been clearly demonstrated that dormancy is induced by abscisic acid (ABA during seed development on the mother plant. After seed dispersal, germination is preceded by a decline in ABA in imbibed seeds, which results from ABA catabolism through 8’-hydroxylation. The hormonal balance between ABA and gibberellins (GAs has been shown to act as an integrator of environmental cues to maintain dormancy or activate germination. The interplay of ABA with other endogenous signals is however less documented. In numerous species, ethylene counteracts ABA signaling pathways and induces germination. In Brassicaceae seeds, ethylene prevents the inhibitory effects of ABA on endosperm cap weakening, thereby facilitating endosperm rupture and radicle emergence. Moreover, enhanced seed dormancy in Arabidopsis ethylene-insensitive mutants results from greater ABA sensitivity. Conversely, ABA limits ethylene action by down-regulating its biosynthesis. Nitric oxide (NO has been proposed as a common actor in the ABA and ethylene crosstalk in seed. Indeed, convergent evidence indicates that NO is produced rapidly after seed imbibition and promotes germination by inducing the expression of the ABA 8’-hydroxylase gene, CYP707A2, and stimulating ethylene production. The role of NO and other nitrogen-containing compounds, such as nitrate, in seed dormancy breakage and germination stimulation has been reported in several species. This review will describe our current knowledge of ABA crosstalk with ethylene and NO, both volatile compounds that have been shown to counteract ABA action in seeds and to improve dormancy release and germination.

  13. Revealing the Cytotoxicity of Residues of Phosphazene Catalysts Used for Synthesis of Poly(ethylene oxide)

    KAUST Repository

    Xia, Yening

    2017-08-24

    We herein report a case study on the toxicity of residual catalyst in metal-free polymer. Eight-arm star-like poly(ethylene oxide)s were successfully synthesized via phosphazene-catalyzed ring-opening polymerization of ethylene oxide using sucrose as an octahydroxy initiator. The products were subjected to MTT assay using human cancer cell lines (MDA-MB-231 and A2780). Comparison between the crude and purified products clearly revealed that the residual phosphazenium salts were considerably cytotoxic regardless of the anionic species, and that the cytotoxicity of more bulky t-BuP4 salt was higher than that of t-BuP2 salt. Such results have therefore put forward the necessity for removal of the catalyst residues from PEO-based polymers synthesized through phosphazene catalysis for bio-related applications, and for the development of less or non-toxic organocatalysts for such polymers.

  14. Revealing the Cytotoxicity of Residues of Phosphazene Catalysts Used for Synthesis of Poly(ethylene oxide)

    KAUST Repository

    Xia, Yening; Shen, Jizhou; Alamri, Haleema; Hadjichristidis, Nikolaos; Zhao, Junpeng; Wang, Yucai; Zhang, Guangzhao

    2017-01-01

    We herein report a case study on the toxicity of residual catalyst in metal-free polymer. Eight-arm star-like poly(ethylene oxide)s were successfully synthesized via phosphazene-catalyzed ring-opening polymerization of ethylene oxide using sucrose as an octahydroxy initiator. The products were subjected to MTT assay using human cancer cell lines (MDA-MB-231 and A2780). Comparison between the crude and purified products clearly revealed that the residual phosphazenium salts were considerably cytotoxic regardless of the anionic species, and that the cytotoxicity of more bulky t-BuP4 salt was higher than that of t-BuP2 salt. Such results have therefore put forward the necessity for removal of the catalyst residues from PEO-based polymers synthesized through phosphazene catalysis for bio-related applications, and for the development of less or non-toxic organocatalysts for such polymers.

  15. Fumigation of Folia belladonnae with 14C-labelled ethylene oxide to reduce the germ number - activity distributions in the drug and preparations made from it

    International Nuclear Information System (INIS)

    Strohmeier, H.

    1988-01-01

    The study described here provided evidence to prove that considerable quantities of ethylene oxide, ethylene chlorhydrin and ethylene glycol are retained, when a drug is fumigated with ethylene oxide under standard fumigation conditions in order to reduce the germ number. Ethylene oxide bound by adsorption may be eliminated from the drug by repeated aeration. If an aqueous-ethanolic percolate is prepared from a drug showing very high levels of ethylene chlorhydrin and then carefully distilled at 40 C using only little pressure, a dry extract can be obtained that contains no such residue. (orig.) [de

  16. pH responsiveness of dendrimer-like poly(ethylene oxide)s.

    Science.gov (United States)

    Feng, Xiaoshuang; Taton, Daniel; Borsali, Redouane; Chaikof, Elliot L; Gnanou, Yves

    2006-09-06

    Poly(ethylene oxide) (PEO) and poly(acrylic acid) (PAA), two polymers known to form pH-sensitive aggregates through noncovalent interactions, were assembled in purposely designed architecture -a dendrimer-like PEO scaffold carrying short inner PAA chains-to produce unimolecular systems that exhibit pH responsiveness. Because of the particular placement of the PAA chains within the dendrimer-like structure, intermolecular complexation between acrylic acid (AA) and ethylene oxide (EO) units-and thus macroscopic aggregation or even mesoscopic micellization-could be avoided in favor of the sole intramolecular complexation. The sensitivity of such interactions to pH was exploited to generate dendrimer-like PEOs that reversibly shrink and expand with the pH. Such PAA-carrying dendrimer-like PEOs were synthesized in two main steps. First, a fifth-generation dendrimer-like PEO was obtained by combining anionic ring-opening polymerization (AROP) of ethylene oxide from a tris-hydroxylated core and selective branching reactions of PEO chain ends. To this end, an AB(2)C-type branching agent was designed: the latter includes a chloromethyl (A) group for its covalent attachment to the arm ends, two geminal hydroxyls (B(2)) protected in the form of a ketal ring for the growth of subsequent PEO generations by AROP, and a vinylic (C) double bonds for further functionalization of the interior of dendrimer-like PEOs. Reiteration of AROP and derivatization of PEO branches allowed us to prepare a dendrimer-like PEO of fourth generation with a total molar mass of 52,000 g x mol(-1), containing 24 external hydroxyl functions and 21 inner vinylic groups in the interior. A fifth generation of PEO chains was generated from this parent dendrimer-like PEO of fourth generation using a "conventional" AB(2)-type branching agent, and 48 PEO branches could be grown by AROP. The 48 outer hydroxy-end groups of the fifth-generation dendrimer-like PEO obtained were subsequently quantitatively

  17. Structure and conductive properties of poly(ethylene oxide)/layered double hydroxide nanocomposite polymer electrolytes

    International Nuclear Information System (INIS)

    Liao, C.-S.; Ye, W.-B.

    2004-01-01

    The oligo(ethylene oxide) modified layered double hydroxide (LDH) prepared by template method was added as a nanoscale nucleating agent into poly(ethylene oxide) (PEO) to form PEO/OLDH nanocomposite electrolytes. The effects of OLDH addition on morphology and conductivities of nanocomposite electrolytes were studied using wide-angle X-ray diffractometer, polarized optical microscopy, differential scanning calorimetry and ionic conductivity measurement. The results show that the exfoliated morphology of nanocomposites is formed due to the surface modification of LDH layers with PEO matrix compatible oligo(ethylene oxide)s. The nanoscale dispersed OLDH layers inhibit the crystal growth of PEO crystallites and result in a plenty amount of intercrystalline grain boundary within PEO/OLDH nanocomposites. The ionic conductivities of nanocomposite electrolytes are enhanced by three orders of magnitude compared to the pure PEO polymer electrolytes at ambient temperature. It can be attributed to the ease transport of Li + along intercrystalline amorphous phase. This novel nanocomposite electrolytes system with high conductivities will be benefited to fabricate the thin-film type of Li-polymer secondary battery

  18. Formyl-ended heterobifunctional poly(ethylene oxide): synthesis of poly(ethylene oxide) with a formyl group at one end and a hydroxyl group at the other end.

    Science.gov (United States)

    Nagasaki, Y; Kutsuna, T; Iijima, M; Kato, M; Kataoka, K; Kitano, S; Kadoma, Y

    1995-01-01

    Well-defined poly(ethylene oxide) (PEO) with a formyl group at one end and a hydroxyl group at the other terminus was synthesized by the anionic ring opening polymerization of ethylene oxide (EO) with a new organometallic initiator possessing an acetal moiety, potassium 3,3-diethoxypropyl alkoxide. Hydrolysis of the acetal moiety produced a formyl group-terminated heterobifunctional PEO with a hydroxyl group at the other end.

  19. Surface grafting of cellulose nanocrystals with poly(ethylene oxide) in aqueous media.

    Science.gov (United States)

    Kloser, Elisabeth; Gray, Derek G

    2010-08-17

    Aqueous suspensions of poly(ethylene oxide)-grafted nanocrystalline cellulose (PEO-grafted NCC) were prepared in order to achieve steric instead of electrostatic stabilization. A two-step process was employed: in the first step NCC suspensions prepared by sulfuric acid hydrolysis were desulfated with sodium hydroxide, and in the second step the surfaces of the crystals were functionalized with epoxy-terminated poly(ethylene oxide) (PEO epoxide) under alkaline conditions. The PEO-grafted samples were analyzed by conductometric titration, ATR-IR, solid-state NMR, MALDI-TOF MS, SEC MALLS, and AFM. The covalent nature of the linkage was confirmed by weight increase and MALDI-TOF analysis. The PEO-grafted cellulose nanocrystals (CNCs) formed a stable colloidal suspension that remained well dispersed, while the desulfated nanoparticles aggregated and precipitated. Upon concentration of the PEO-grafted aqueous NCC suspension, a chiral nematic phase was observed.

  20. Photoionization and ion cyclotron resonance studies of the ion chemistry of ethylene oxide

    Science.gov (United States)

    Corderman, R. R.; Williamson, A. D.; Lebreton, P. R.; Buttrill, S. E., Jr.; Beauchamp, J. L.

    1976-01-01

    The formation of the ethylene oxide molecular ion and its subsequent ion-molecule reactions leading to the products C2H5O(+) and C3H5O(+) have been studied using time-resolved photoionization mass spectroscopy, ion cyclotron resonance spectroscopy, and photoelectron spectroscopy. An examination of the effects of internal energy on reactivity shows that the ratio of C3H5O(+) to C2H5O(+) increases by an order of magnitude with a single quantum of vibrational energy. The formation of (C2H4O/+/)-asterisk in a collision-induced isomerization is found which yields a ring-opened structure by C-C bond cleavage. The relaxed ring-opened C2H4O(+) ion reacts with neutral ethylene oxide by CH2(+) transfer to yield an intermediate product ion C3H6O(+) which gives C3H5O(+) by loss of H.

  1. Experimental ethylene oxide neuropathy. Chronic exposure to 250 ppm in rats

    Energy Technology Data Exchange (ETDEWEB)

    Ohnishi, A.; Yamamoto, T.; Inoue, N.; Tanaka, I.; Koga, M.

    1985-12-01

    In Wistar rats subjected to a six-hour exposure to ethylene oxide (ETO) at the concentration of 250 parts per million once a day, five times a week for 9 months, histopathologic studies of myelinated fibers of the proximal sural, distal sural and peroneal nerves and of the fasciculus gracilis at the fifth thoracic and third cervical segments of the spinal cord were performed to reveal whether ETO of such concentration produces the degeneration of the primary sensory neuron. Throughout the study, no definite abnormality of the gait or posture was observed in both control and test rats. Qualitative histologic studies disclosed preferential distal axonal degeneration of myelinated fibers in both sural nerves and gracile fascicles in test rats, although the extent of the distribution and the severity of the degenerative findings were variable among test rats. Therefore, it was concluded that exposure to 250 ppm ethylene oxide produces central-peripheral distal axonal degeneration of the primary sensory neuron in rats.

  2. Are plant endogenous factors like ethylene modulators of the early oxidative stress induced by mercury?

    Directory of Open Access Journals (Sweden)

    M Belén eMontero-Palmero

    2014-08-01

    Full Text Available The induction of oxidative stress is one of the quickest symptoms appearing in plants subjected to metal stress. A transcriptional analysis of the early responses of alfalfa (Medicago sativa seedlings to mercury (Hg; 3 µM for 3, 6 and 24 h showed that up-regulation of genes responding to ethylene were up-regulated, a phytohormone known to mediate in the cellular redox homeostasis. In this mini-review we have compared these quick responses with two other concurrent transcriptomic analysis in Barrel medic (Medicago truncatula and barley (Hordeum vulgare under Hg stress. Besides ethylene, ABA and jasmonate related genes were up-regulated, all of them are endogenous factors known to intervene in oxidative stress responses. The information obtained may target future work to understand the cellular mechanisms triggered by Hg, enabling biotechnological approaches to diminish Hg-induced phytotoxicity.

  3. Ethylene oxide gas sterilization does not reduce the osteoinductive potential of demineralized bone in rats

    DEFF Research Database (Denmark)

    Solheim, E; Pinholt, E M; Bang, G

    1995-01-01

    It has been shown that different sterilization procedures of demineralized bone may influence its osteoinductive properties. The aim of this study was to evaluate the effect of ethylene oxide sterilization for 1, 3, and 6 hours on the osteoinductive potential of allogeneic demineralized bone...... implanted heterotopically in rats. Sixty male Wistar rats were randomly assigned to one of four groups, A through D, and four demineralized bone chips (2.8 mg) were implanted in a pouch created between the right oblique abdominal muscles in each animal. In Group A, the demineralized bone was implanted...... without prior sterilization of the material, whereas the demineralized bone implanted in Groups B, C, and D had been sterilized in ethylene oxide gas for 1, 3, or 6 hours, respectively, and aerated for 48 hours. At 4 weeks postoperatively, bone formation was evaluated quantitatively by strontium 85 uptake...

  4. Using solvent-free sample preparation to promote protonation of poly(ethylene oxide)s with labile end-groups in matrix-assisted laser desorption/ionisation.

    Science.gov (United States)

    Mazarin, Michael; Phan, Trang N T; Charles, Laurence

    2008-12-01

    Protonation is usually required to observe intact ions during matrix-assisted laser desorption/ionization (MALDI) of polymers containing fragile end-groups while cation adduction induces chain-end degradation. These polymers, generally obtained via living free radical polymerization techniques, are terminated with a functionality in which a bond is prone to homolytic cleavage, as required by the polymerization process. A solvent-free sample preparation method was used here to avoid salt contaminant from the solvent traditionally used in the dried-droplet MALDI procedure. Solvent-based and solvent-free sample preparations were compared for a series of three poly(ethylene oxide) polymers functionalized with a labile end-group in a nitroxide-mediated polymerization reaction, using 2,4,6-trihydroxyacetophenone (THAP) as the matrix without any added salt. Intact oligomer ions could only be produced as protonated molecules in solvent-free MALDI while sodium adducts of degraded polymers were formed from the dried-droplet samples. Although MALDI analysis was performed at the laser threshold, fragmentation of protonated macromolecules was still observed to occur. However, in contrast to sodiated molecules, dissociation of protonated oligomers does not involve the labile C--ON bond of the end-group. As the macromolecule size increased, protonation appeared to be less efficient and sodium adduction became the dominant ionization process, although no sodium salt was added in the preparation. Formation of sodiated degraded macromolecules would be dictated by increasing cation affinity as the size of the oligomers increases and would reveal the presence of salts at trace levels in the MALDI samples.

  5. Reaction path of the oxidative coupling of methane over a lithium-doped magnesium oxide catalyst : Factors affecting the Rate of Total Oxidation of Ethane and Ethylene

    NARCIS (Netherlands)

    Roos, J.A.; Korf, S.J.; Veehof, R.H.J.; van Ommen, J.G.; Ross, J.R.H.

    1989-01-01

    Experiments using gas mixtures of O2, C2H6 or C2H4 and CH4 or He have been carried out with a Li/MgO catalyst using a well-mixed reaction system which show that the total oxidation products, CO and CO2, are formed predominantly from ethylene, formed in the oxidative coupling of methane. It is

  6. The influence of sonication of poly(ethylene oxide) solutions to the quality of resulting electrospun nanofibrous mats

    Czech Academy of Sciences Publication Activity Database

    Peer, Petra; Filip, Petr; Polášková, M.; Kucharczyk, P.; Pavlínek, V.

    2016-01-01

    Roč. 126, April (2016), s. 101-106 ISSN 0141-3910 Institutional support: RVO:67985874 Keywords : electrospinning * nanofibres * poly(ethylene oxide) * sonication * degradation Subject RIV: BK - Fluid Dynamics Impact factor: 3.386, year: 2016

  7. Magnetorheological behaviour and electrospinning of poly(ethylene oxide) suspensions with magnetic nanoparticles

    Czech Academy of Sciences Publication Activity Database

    Peer, Petra; Stěnička, M.; Sedlačík, M.; Filip, Petr; Pavlínek, V.

    2016-01-01

    Roč. 27, č. 7 (2016), s. 898-903 ISSN 1045-389X R&D Projects: GA ČR(CZ) GAP105/11/2342 Grant - others:GA MŠk(CZ) ED2.1.00/03.0111 Institutional support: RVO:67985874 Keywords : magnetorheological * electrospinning * poly(ethylene oxide) * nanofibres * sedimentation * rheology Subject RIV: BK - Fluid Dynamics Impact factor: 2.255, year: 2016

  8. Unique Crystal Orientation of Poly(ethylene oxide) Thin Films by Crystallization Using a Thermal Gradient

    DEFF Research Database (Denmark)

    Gbabode, Gabin; Delvaux, Maxime; Schweicher, Guillaume

    2017-01-01

    Poly(ethylene oxide), (PEO), thin films of different thicknesses (220, 450, and 1500 nm) and molecular masses (4000, 8000, and 20000 g/mol) have been fabricated by spin-coating of methanol solutions onto glass substrates. All these samples have been recrystallized from the melt using a directional......, to significantly decrease the distribution of crystal orientation obtained after crystallization using the thermal gradient technique....

  9. Copolymerization of poly (ethylene oxide) and poly (methyl methacrylate) initiated by ceric ammonium nitrate

    International Nuclear Information System (INIS)

    Gomes, A.S.; Ferreira, A.A.; Coutinho, F.M.B.; Marinho, J.R.D.

    1984-01-01

    Cerium (IV) salts such as the ceric ammonium nitrate and ceric ammonium sulfate in aqueous acid solution with reducing agents such as alcohols, thiols, glycols, aldehydes and amines are well known initiators of vinyl polymerization. In this work, the polymerization of methyl methacrylate initiated by ceric ammonium nitrate/HNO 3 -poly(ethylene oxide) with hydroxyl end group system was studied in aqueous solution at 25 0 C to obtain block copolymers. (Author) [pt

  10. Nonfouling poly(ethylene oxide) layers end-tethered to polydopamine

    Czech Academy of Sciences Publication Activity Database

    Pop-Georgievski, Ognen; Verreault, D.; Diesner, M. O.; Proks, Vladimír; Heissler, S.; Rypáček, František; Koelsch, P.

    2012-01-01

    Roč. 28, č. 40 (2012), s. 14273-14283 ISSN 0743-7463 R&D Projects: GA ČR GAP108/11/1857; GA ČR GPP108/12/P624 Institutional research plan: CEZ:AV0Z40500505 Institutional support: RVO:61389013 Keywords : poly(ethylene oxide) * polydopamine * biomaterials Subject RIV: CD - Macromolecular Chemistry Impact factor: 4.187, year: 2012

  11. Poly(organo phosphazene) nanoparticles surface modified with poly(ethylene oxide).

    Science.gov (United States)

    Vandorpe, J; Schacht, E; Stolnik, S; Garnett, M C; Davies, M C; Illum, L; Davis, S S

    1996-10-05

    The use of biodegradable derivatives of poly(organo phosphazenes) for the preparation of nanoparticles and their surface modification with the novel poly(ethylene oxide) derivative of poly(organo phosphazene) has been assessed using a range of in vitro characterization methods. The nanoparticles were produced by the precipitation solvent evaporation method from the derivative co-substituted with phenylalanine and glycine ethyl ester side groups. A reduction in particle size to less than 200 nm was achieved by an increase in pH of the preparation medium. The formation (and colloidal stability) of these nanoparticles seems to be controlled by two opposite effects: attractive hydrophobic interactions between phenylalanine ester groups and electrostatic repulsions arising from the carboxyl groups formed due to (partial) hydrolysis of the ester bond(s) at the high pH of the preparation medium. The poly[(glycine ethyl ester)phosphazene] derivative containing 5000-Da poly(ethylene oxide) as 5% of the side groups was used for the surface modification of nanoparticles. Adsorbed onto the particles, the polymer produced a thick coating layer of approximately 35 nm. The coated nanoparticles exhibited reduced surface negative potential and improved colloidal stability toward electrolyte-induced flocculation, relative to the uncoated system. However, the steric stabilization provided was less effective than that of a Poloxamine 908 coating. This difference in effectiveness of the steric stabilization might indicate that, although both the stabilizing polymers possess a 5000-Da poly(ethylene oxide) moiety, there is a difference in the arrangements of these poly(ethylene oxide) chains at the particle surface. (c) 1996 John Wiley & Sons, Inc.

  12. Phase Separation and Elastic Properties of Poly(Trimethylene Terephthalate)-block-poly(Ethylene Oxide) Copolymers

    OpenAIRE

    Elżbieta Piesowicz; Sandra Paszkiewicz; Anna Szymczyk

    2016-01-01

    A series of poly(trimethylene terephthalate)-block-poly(ethylene oxide) (PTT-b-PEOT) copolymers with different compositions of rigid PTT and flexible PEOT segments were synthesized via condensation in the melt. The influence of the block length and the block ratio on the micro-separated phase structure and elastic properties of the synthesized multiblock copolymers was studied. The PEOT segments in these copolymers were kept constant at 1130, 2130 or 3130 g/mol, whereas the PTT content varied...

  13. Hydrolytic Degradation of Poly (ethylene oxide)-block-Polycaprolactone Worm Micelles

    OpenAIRE

    Geng, Yan; Discher, Dennis E.

    2005-01-01

    Spherical micelles and nanoparticles made with degradable polymers have been of great interest for therapeutic application, but degradation induced changes in a spherical morphology can be subtle and mechanism/kinetics appears poorly understood. Here, we report the first preparation of giant and flexible worm micelles self-assembled from degradable copolymer poly (ethylene oxide)-block-polycaprolactone. Such worm micelles spontaneously shorten to generate spherical micelles, triggered by poly...

  14. Iron oxide/cassava starch-supported Ziegler-Natta catalysts for in situ ethylene polymerization.

    Science.gov (United States)

    Chancharoenrith, Sittikorn; Kamonsatikul, Choavarit; Namkajorn, Montree; Kiatisevi, Supavadee; Somsook, Ekasith

    2015-03-06

    Iron oxide nanoparticles were used as supporters for in situ polymerization to produce polymer nanocomposites with well-dispersed fillers in polymer matrix. Iron oxide could be sustained as colloidal solutions by cassava starch to produce a good dispersion of iron oxide in the matrix. New supports based on iron oxide/cassava starch or cassava starch for Ziegler-Natta catalysts were utilized as heterogeneous supporters for partially hydrolyzed triethylaluminum. Then, TiCl4 was immobilized on the supports as catalysts for polymerization of ethylene. High-density polyethylene (HDPE) composites were obtained by the synthesized catalysts. A good dispersion of iron oxide/cassava starch particles was observed in the synthesized polymer matrix promoting to good mechanical properties of HDPE. Copyright © 2014 Elsevier Ltd. All rights reserved.

  15. Characterization of Titanium Oxide Nanoparticles Obtained by Hydrolysis Reaction of Ethylene Glycol Solution of Alkoxide

    OpenAIRE

    Naofumi Uekawa; Naoya Endo; Keisuke Ishii; Takashi Kojima; Kazuyuki Kakegawa

    2012-01-01

    Transparent and stable sols of titanium oxide nanoparticles were obtained by heating a mixture of ethylene glycol solution of titanium tetraisopropoxide (TIP) and a NH3 aqueous solution at 368 K for 24 h. The concentration of NH3 aqueous solution affected the structure of the obtained titanium oxide nanoparticles. For NH3 aqueous solution concentrations higher than 0.2 mol/L, a mixture of anatase TiO2 nanoparticles and layered titanic acid nanoparticles was obtained. The obtained sol was very...

  16. Newly designed PdRuBi/N-Graphene catalysts with synergistic effects for enhanced ethylene glycol electro-oxidation

    International Nuclear Information System (INIS)

    Li, Tengfei; Huang, Yiyin; Ding, Kui; Wu, Peng; Abbas, Syed Comail; Ghausi, Muhammad Arsalan; Zhang, Teng; Wang, Yaobing

    2016-01-01

    Graphical abstract: We rationally design and synthesize a ternary PdRuBi/NG catalyst with significantly enhanced catalytic activity with synergetic effect of Ru and Bi towards ethylene glycol electro-oxidation. - Abstract: Palladium (Pd)-based catalysts are appealing electro-catalysts for alcohol oxidation reaction in fuel cell, but still not efficient as the complicated oxidation process and sluggish kinetic. Here we rationally design and synthesize a PdRuBi/NG tri-metallic catalyst with space synergetic effect for enhanced ethylene glycol electro-oxidation, in which both Ru and Bi in the catalyst are synergistic effective in promoting catalytic activity of Pd catalytic interlayer by electronic effect and surface modification mechanism respectively. It shows 4.2 times higher peak current density towards ethylene glycol electro-oxidation than commercial Pd/C catalyst, and the catalytic durability is also greatly improved.

  17. Characterization of Titanium Oxide Nanoparticles Obtained by Hydrolysis Reaction of Ethylene Glycol Solution of Alkoxide

    Directory of Open Access Journals (Sweden)

    Naofumi Uekawa

    2012-01-01

    Full Text Available Transparent and stable sols of titanium oxide nanoparticles were obtained by heating a mixture of ethylene glycol solution of titanium tetraisopropoxide (TIP and a NH3 aqueous solution at 368 K for 24 h. The concentration of NH3 aqueous solution affected the structure of the obtained titanium oxide nanoparticles. For NH3 aqueous solution concentrations higher than 0.2 mol/L, a mixture of anatase TiO2 nanoparticles and layered titanic acid nanoparticles was obtained. The obtained sol was very stable without formation of aggregated precipitates and gels. Coordination of ethylene glycol to Ti4+ ions inhibited the rapid hydrolysis reaction and aggregation of the obtained nanoparticles. The obtained titanium oxide nanoparticles had a large specific surface area: larger than 350 m2/g. The obtained titanium oxide nanoparticles showed an enhanced adsorption towards the cationic dye molecules. The selective adsorption corresponded to presence of layered titanic acid on the obtained anatase TiO2 nanoparticles.

  18. The Enhancement of the Selectivity of Complex Reactions by a Catalytic Membrane Reactor -Ethylene Oxidation Over a Ag Catalyst Supported in a Ceramic Membrane-

    OpenAIRE

    馮, 臨; 小林, 正義; Lin, FENG; Masayoshi, KOBAYASHI

    1991-01-01

    This research demonstrated that, using a membrane reactor consisting of a tubular, microporous, glass-ceramic membrane, it is possible to achieve selective oxidation of ethylene to ethylene oxide with an Ag catalyst. In experiments which a reaction temperature range of 115 to 300℃ and a contact time of 1.5 to 5 seconds, resulting data illustrated the following characteristics of this membrane reactor : 1) compared with a classic tubular reactor, the selectivity of ethylene oxide is increased ...

  19. Effects of gamma irradiation in graphene/poly (ethylene oxide) nanocomposites

    International Nuclear Information System (INIS)

    Braz, Elton P.; Goncalves, Natercia Antunes; Araujo, Patricia L.B.; Araujo, Elmo S.

    2013-01-01

    Nanotechnology is the understanding and control of matter in dimensions between 1 and 100nm. In such small matter portions, improved or even new properties may arise, as a direct consequence of reduced size. Thus, the development of multifunctional nanomaterials is nowadays one of the main goals of the materials research field. In this context, we produced graphene sheets through ultrasound exfoliation of graphite oxide, followed by chemical reduction. Composite nanofibers of these graphene sheets with biocompatible polymer poly (ethylene oxide) (PEO) were obtained by electrospinning technique, and irradiated up to 75kGy dose to assess the effects of gamma irradiation in the molecular structure of these composite nanomaterial. Our findings showed that PEO is quite resistant to radiation damage and that the incorporation of graphene oxide has no significant influence on its radiostability. (author)

  20. V2O5 xerogel-poly(ethylene oxide) hybrid material: Synthesis, characterization, and electrochemical properties

    International Nuclear Information System (INIS)

    Guerra, Elidia M.; Ciuffi, Katia J.; Oliveira, Herenilton P.

    2006-01-01

    In this work, we report the synthesis, characterization, and electrochemical properties of vanadium pentoxide xerogel-poly(ethylene oxide) (PEO) hybrid materials obtained by varying the average molecular weight of the organic component as well as the components' ratios. The materials were characterized by X-ray diffraction, ultraviolet/visible and infrared spectroscopies, thermogravimetric analysis, scanning electron microscopy, electron paramagnetic resonance, and cyclic voltammetry. Despite the presence of broad and low intensity peaks, the X-ray diffractograms indicate that the lamellar structure of the vanadium pentoxide xerogel is preserved, with increase in the interplanar spacing, giving evidence of a low-crystalline structure. We found that the electrochemical behaviour of the hybrid materials is quite similar to that found for the V 2 O 5 xerogel alone, and we verified that PEO leads to stabilization and reproducibility of the Li + electrochemical insertion/de-insertion into the V 2 O 5 xerogel structure, which makes these materials potential components of lithium ion batteries. - Graphical abstract: The synthesis, structural and electrochemical properties of vanadium pentoxide xerogel-poly(ethylene oxide) hybrid materials have been described. Despite the presence of broad and low intensity peaks, the X-ray diffractograms indicate that the lamellar structure of the vanadium pentoxide xerogel is preserved. The cyclic voltammetry technique demonstrated that PEO intercalation provides an improvement in the electrochemical properties, mainly with respect to the lithium electroinsertion process into the oxide matrix

  1. Extrusion of polysaccharide nanocrystal reinforced polymer nanocomposites through compatibilization with poly(ethylene oxide).

    Science.gov (United States)

    Pereda, Mariana; El Kissi, Nadia; Dufresne, Alain

    2014-06-25

    Polysaccharide nanocrystals with a rodlike shape but with different dimensions and specific surface area were prepared from cotton and capim dourado cellulose, and with a plateletlike morphology from waxy maize starch granules. The rheological behavior of aqueous solutions of poly(ethylene oxide) (PEO) with different molecular weights when adding these nanoparticles was investigated evidencing specific interactions between PEO chains and nanocrystals. Because PEO also bears hydrophobic moieties, it was employed as a compatibilizing agent for the melt processing of polymer nanocomposites. The freeze-dried mixtures were used to prepare nanocomposite materials with a low density polyethylene matrix by extrusion. The thermal and mechanical behavior of ensuing nanocomposites was studied.

  2. Hydrolytic degradation of poly(ethylene oxide)-block-polycaprolactone worm micelles.

    Science.gov (United States)

    Geng, Yan; Discher, Dennis E

    2005-09-21

    Spherical micelles and nanoparticles made with degradable polymers have been of great interest for therapeutic application, but degradation-induced changes in a spherical morphology can be subtle and mechanism/kinetics appears poorly understood. Here, we report the first preparation of giant and flexible worm micelles self-assembled from degradable copolymer poly(ethylene oxide)-block-polycaprolactone. Such worm micelles spontaneously shorten to generate spherical micelles, triggered by polycaprolactone hydrolysis, with distinct mechanism and kinetics from that which occurs in bulk material.

  3. Evaluation of miscibility of poly(epichlorohydrin-co-ethylene oxide) and poly(methylmethacrylate) blends

    International Nuclear Information System (INIS)

    Turchete, Renato; Felisberti, Maria Isabel

    1999-01-01

    The miscibility of blends of poly(methylmethacrylate), (PMMA) and poly(epichlorohydrin-co-ethylene oxide), (ECO) were investigated by differential scanning calorimetry. The ECO was fractionated using two different systems: a solvent-non solvent system and by cooling the solution in tetrahydrofuran in the temperature range from 20 to 0 deg C. The fractions with different composition and molecular weight were used to prepare the blends by casting from solution in tetrahydrofuran. The blends exhibit two glass transitions shifted in relation to the glass transitions of the pure polymers, indicating a partial miscibility. Blends containing copolymer richer in epichlorohydrin segments were more miscible than blends of non-fractionated ECO. (author)

  4. Integrating nitric oxide into salicylic acid and jasmonic acid/ethylene plant defense pathways

    DEFF Research Database (Denmark)

    Mur, Luis A J; Prats, Elena; Pierre, Sandra

    2013-01-01

    to be tailored to particular biotic stresses. Nitric oxide (NO) has emerged as a major signal influencing resistance mediated by both signalling pathways but no attempt has been made to integrate NO into established SA/JA/ET interactions. NO has been shown to act as an inducer or suppressor of signalling along......Plant defence against pests and pathogens is known to be conferred by either salicylic acid (SA) or jasmonic acid (JA)/ethylene (ET) pathways, depending on infection or herbivore-grazing strategy. It is well attested that SA and JA/ET pathways are mutually antagonistic allowing defence responses...

  5. Synthesis and properties of highly dispersed ionic silica-poly(ethylene oxide) nanohybrids.

    KAUST Repository

    Fernandes, Nikhil J

    2013-02-04

    We report an ionic hybrid based on silica nanoparticles as the anion and amine-terminated poly(ethylene oxide) (PEO) as a cation. The charge on the nanoparticle anion is carried by the surface hydroxyls. SAXS and TEM reveal an exceptional degree of dispersion of the silica in the polymer and high degree of order in both thin film and bulk forms. In addition to better dispersion, the ionic hybrid shows improved flow characteristics compared to silica/PEO mixtures in which the ionic interactions are absent.

  6. Synthesis and properties of highly dispersed ionic silica-poly(ethylene oxide) nanohybrids.

    KAUST Repository

    Fernandes, Nikhil J; Akbarzadeh, Johanna; Peterlik, Herwig; Giannelis, Emmanuel P

    2013-01-01

    We report an ionic hybrid based on silica nanoparticles as the anion and amine-terminated poly(ethylene oxide) (PEO) as a cation. The charge on the nanoparticle anion is carried by the surface hydroxyls. SAXS and TEM reveal an exceptional degree of dispersion of the silica in the polymer and high degree of order in both thin film and bulk forms. In addition to better dispersion, the ionic hybrid shows improved flow characteristics compared to silica/PEO mixtures in which the ionic interactions are absent.

  7. Emission characteristics of plastic syringes sterilized with ethylene oxide--a controlled study.

    Science.gov (United States)

    Chien, Yeh-Chung; Su, Po-Chi; Lee, Lien-Hsiung; Chen, Chang-Yuh

    2009-11-01

    This study examined the emission characteristics of ethylene oxide (EO)-sterilized syringes under various environmental conditions, aiming to develop control strategies to minimize worker exposure. Experiments were performed in a facility in which temperature, relative humidity (RH), and air change rate (ACR) were controlled. Analytical results indicate that the main effects of the four test variables on kinetic parameters were statistically significant (p Plastic content, temperature, RH, and ACR affected EO emissions. ACR is an achievable means of control; however, the aeration area/system should be isolated to ensure adequate ventilation is achieved.

  8. Effectiveness of ethylene oxide and gamma irradiation on the microbiological population of three types of paprika

    International Nuclear Information System (INIS)

    Franco, S.L.; Gimenez, J.L.; Sanchez, F.M.; Romojaro, F.

    1986-01-01

    The effectiveness of ethylene oxide and the gamma irradiation sterilizing treatments on the microbiological population was studied in three types of Spanish paprika, stored in a cold chamber (4 0 C) and at room temperature (16-38.8 0 C) over an experimental period of 285 days. The controlled microorganisms were: mesophilic aerobes, coliforms, sulfite reducing anaerobes, yeasts, molds, and Salmonella. The presence of aflatoxins was also studied. The results showed that both sterilizing treatments reduced the microbiological population to below the permissible levels recommended by the International Commission on Microbiological Specification for Food. Nevertheless, it was interesting that the gamma irradiation treatment was more effective

  9. Adhesion mapping of chemically modified and poly(ethylene oxide)-grafted glass surfaces

    OpenAIRE

    Jogikalmath, G.; Stuart, J.K.; Pungor, A.; Hlady, V.

    1999-01-01

    Two-dimensional mapping of the adhesion pull-off forces was used to study the origin of surface heterogeneity in the grafted poly(ethylene oxide) (PEO) layer. The variance of the pull-off forces measured over the μm-sized regions after each chemical step of modifying glass surfaces was taken to be a measure of the surface chemical heterogeneity. The attachment of γ-glycidoxypropyltrimethoxy silane (GPS) to glass decreased the pull-off forces relative to the clean glass and made the surface mo...

  10. Metal oxides modified NiO catalysts for oxidative dehydrogenation of ethane to ethylene

    KAUST Repository

    Zhu, Haibo; Dong, Hailin; Laveille, Paco; Saih, Youssef; Caps, Valerie; Basset, Jean-Marie

    2014-01-01

    in contrast to pure NiO. The introduction of group IV, V and VI transition metals into NiO decreases the catalytic activity in ethane ODH. However, the ethylene selectivity is enhanced with the highest level for the Ni-W-O and Ni-Ti-O catalysts. As a result

  11. Microstructural study of a nitroxide-mediated poly(ethylene oxide)/polystyrene block copolymer (PEO-b-PS) by electrospray tandem mass spectrometry.

    Science.gov (United States)

    Girod, Marion; Phan, Trang N T; Charles, Laurence

    2008-08-01

    Electrospray ionization tandem mass spectrometry has been used to characterize the microstructure of a nitroxide-mediated poly(ethylene oxide)/polystyrene block copolymer, called SG1-capped PEO-b-PS. The main dissociation route of co-oligomers adducted with lithium or silver cation was observed to proceed via the homolytic cleavage of a C-ON bond, aimed at undergoing reversible homolysis during nitroxide mediated polymerization. This cleavage results in the elimination of the terminal SG1 end-group as a radical, inducing a complete depolymerization process of the PS block from the so-formed radical cation. These successive eliminations of styrene molecules allowed a straightforward determination of the PS block size. An alternative fragmentation pathway of the radical cation was shown to provide structural information on the junction group between the two blocks. Proposed dissociation mechanisms were supported by accurate mass measurements. Structural information on the SG1 end-group could be reached from weak abundance fragment ions detected in the low m/z range of the MS/MS spectrum. Amongst fragments typically expected from PS dissociation, only beta ions were produced. Moreover, specific dissociation of the PEO block was not observed to occur in MS/MS, suggesting that these rearrangement reactions do not compete effectively with dissociations of the odd-electron fragment ions. Information about the PEO block length and the initiated end-group were obtained in MS(3) experiments.

  12. Electrochemical performance for the electro-oxidation of ethylene glycol on a carbon-supported platinum catalyst at intermediate temperature

    International Nuclear Information System (INIS)

    Kosaka, Fumihiko; Oshima, Yoshito; Otomo, Junichiro

    2011-01-01

    Highlights: → High oxidation current in ethylene glycol electro-oxidation at intermediate temperature. → High C-C bond dissociation ratio of ethylene glycol at intermediate temperature. → Low selectivity for CH 4 in ethylene glycol electro-oxidation. → High selectivity for CO 2 according to an increase in steam to carbon ratios. - Abstract: To determine the kinetic performance of the electro-oxidation of a polyalcohol operating at relatively high temperatures, direct electrochemical oxidation of ethylene glycol on a carbon supported platinum catalyst (Pt/C) was investigated at intermediate temperatures (235-255 o C) using a single cell fabricated with a proton-conducting solid electrolyte, CsH 2 PO 4 , which has high proton conductivity (>10 -2 S cm -1 ) in the intermediate temperature region. A high oxidation current density was observed, comparable to that for methanol electro-oxidation and also higher than that for ethanol electro-oxidation. The main products of ethylene glycol electro-oxidation were H 2 , CO 2 , CO and a small amount of CH 4 formation was also observed. On the other hand, the amounts of C 2 products such as acetaldehyde, acetic acid and glycolaldehyde were quite small and were lower by about two orders of magnitude than the gaseous reaction products. This clearly shows that C-C bond dissociation proceeds almost to completion at intermediate temperatures and the dissociation ratio reached a value above 95%. The present observations and kinetic analysis suggest the effective application of direct alcohol fuel cells operating at intermediate temperatures and indicate the possibility of total oxidation of alcohol fuels.

  13. Electrochemical performance for the electro-oxidation of ethylene glycol on a carbon-supported platinum catalyst at intermediate temperature

    Energy Technology Data Exchange (ETDEWEB)

    Kosaka, Fumihiko; Oshima, Yoshito [Department of Environment Systems, Graduate School of Frontier Sciences, University of Tokyo, 5-1-5 Kashiwanoha, Kashiwa, Chiba 277-8563 (Japan); Otomo, Junichiro, E-mail: otomo@k.u-tokyo.ac.jp [Department of Environment Systems, Graduate School of Frontier Sciences, University of Tokyo, 5-1-5 Kashiwanoha, Kashiwa, Chiba 277-8563 (Japan)

    2011-11-30

    Highlights: > High oxidation current in ethylene glycol electro-oxidation at intermediate temperature. > High C-C bond dissociation ratio of ethylene glycol at intermediate temperature. > Low selectivity for CH{sub 4} in ethylene glycol electro-oxidation. > High selectivity for CO{sub 2} according to an increase in steam to carbon ratios. - Abstract: To determine the kinetic performance of the electro-oxidation of a polyalcohol operating at relatively high temperatures, direct electrochemical oxidation of ethylene glycol on a carbon supported platinum catalyst (Pt/C) was investigated at intermediate temperatures (235-255 {sup o}C) using a single cell fabricated with a proton-conducting solid electrolyte, CsH{sub 2}PO{sub 4}, which has high proton conductivity (>10{sup -2} S cm{sup -1}) in the intermediate temperature region. A high oxidation current density was observed, comparable to that for methanol electro-oxidation and also higher than that for ethanol electro-oxidation. The main products of ethylene glycol electro-oxidation were H{sub 2}, CO{sub 2}, CO and a small amount of CH{sub 4} formation was also observed. On the other hand, the amounts of C{sub 2} products such as acetaldehyde, acetic acid and glycolaldehyde were quite small and were lower by about two orders of magnitude than the gaseous reaction products. This clearly shows that C-C bond dissociation proceeds almost to completion at intermediate temperatures and the dissociation ratio reached a value above 95%. The present observations and kinetic analysis suggest the effective application of direct alcohol fuel cells operating at intermediate temperatures and indicate the possibility of total oxidation of alcohol fuels.

  14. High-efficiency synthesis of dendrimer-like poly(ethylene oxide) via “arm-first” approach

    KAUST Repository

    Zhu, Saisai

    2017-04-14

    In this study, a dendrimer-like polymer based on poly(ethylene oxide) (PEO) was synthesized through a combination of anionic ring-opening polymerization (AROP) and click reaction via arm-first method. Firstly, the polymeric arm, a linear PEO with one alkynyl group and two bromo groups, was synthesized by AROP of ethylene oxide followed by functionalization with propargyl bromide and esterified with 2-bromopropionic bromide. Second, a star PEO carrying three azide groups was synthesized though AROP of ethylene oxide used 1,1,1-tris(hydrosymethyl) ethane as initiator followed esterificated with 2-bromopropionic acid and azidation. By azide–alkyne click reactions between the azide-terminated PEO star polymer and linear PEO with functionalization alkynyl group, a three generation dendrimer-like PEO, G3-PEO-24Br, was successfully synthesized. The resulting polymers were observed to have precisely controlled molecular weights and compositions with narrow molecular weight distributions.

  15. Effects of ethylene oxide sterilization on 82: 18 PLLA/PGA copolymer craniofacial fixation plates.

    Science.gov (United States)

    Pietrzak, William S

    2010-01-01

    Bioabsorbable devices are generally susceptible to some form of degradation or alteration of material properties in response to exposure to the terminal sterilization cycle. In addition to affecting the material strength, sterilization can also increase the rate of hydrolysis, both of which can impact clinical performance. The impact of sterilization on the material/device is unpredictable and must be empirically determined. This study examined the effects of ethylene oxide treatment on the material properties of LactoSorb 82:18 poly(L-lactic acid)-poly(glycolic acid) craniofacial plates. Compared with untreated control plates, there was no effect on the initial inherent viscosity (1.3 dL/g), the glass transition temperature (58 degrees C), or on the flexural mechanical properties. Furthermore, there was no effect on the in vitro rate of hydrolysis and mechanical strength loss profile. This provides evidence that the ethylene oxide sterilization cycle is compatible with these copolymer plates and that such treatment should not affect the clinical performance.

  16. Gas chromatographic determination with electron capture detection of residual ethylene oxide in intraocular lenses

    Energy Technology Data Exchange (ETDEWEB)

    Kikuchi, H.; Nakamura, A.; Tsuji, K.

    1988-01-01

    A sensitive method is described to determine trace quantities of ethylene oxide (EO) in EO-sterilized intraocular lenses (IOLs). An IOL is dipped in ethanol containing 0.25 ppm propylene oxide (PO) in a 4 mL vial, 2 drops of freshly distilled hydrobromic acid is added through a septum, and the mixture is warmed at 50/sup 0/C for 24 h. It is then neutralized by vigorous shaking with sodium bicarbonate, dehydrated with anhydrous sodium sulfate, and filtered. The filtrate is injected into a gas chromatograph with electron-capture detection, and the peak height ratio of ethylene bromohydrin/propylene bromohydrin is measured. EO residue is calculated from the calibration curve obtained through a similar procedure with the standard EO/PO solutions. The limit of determination is 0.04 ..mu..g/lens (ca 2.0 ppm). When EO residue levels were determined for IOLs sampled at 3 different aeration periods after stabilization, the authors found that 9 days of aeration was necessary to meet the US Food and Drug Administration proposed limit for EO residue in IOLs.

  17. Lithium ion conductivity of molecularly compatibilized chitosan-poly(aminopropyltriethoxysilane)-poly(ethylene oxide) nanocomposites

    International Nuclear Information System (INIS)

    Fuentes, S.; Retuert, P.J.; Gonzalez, G.

    2007-01-01

    Films of composites of chitosan/poly(aminopropyltriethoxysilane)/poly(ethylene oxide) (CHI/pAPS/PEO) containing a fixed amount of lithium salt are studied. The ternary composition diagram of the composites, reporting information on the mechanic stability, the transparence and the electrical conductivity of the films, shows there is a window in which the molecular compatibility of the components is optimal. In this window, defined by the components ratios CHI/PEO 3:2, pAPS/PEO 2:3 and CHI/PEO 1:2, there is a particular composition Li x (CHI) 1 (PEO) 2 (pAPS) 1.2 for which the conductivity reaches a value of 1.7 x 10 -5 S cm -1 at near room temperature. Considering the balance between the Lewis acid and basic sites available in the component and the observed stoichiometry limits of formed polymer complexes, the conductivity values of these products may be understood by the formation of a layered structure in which the lithium ions, stabilized by the donors, poly(ethylene oxide) and/or poly(aminopropyltriethoxysilane), are intercalated in a chitosan matrix

  18. Microbiological Load Of Ethylene Oxide Sterilized Medical Devices And Its Elimination By Cobalt 60 Source

    International Nuclear Information System (INIS)

    Bashir, R.; Afroze, B.; Zulfiqar, H. F.; Saleem, R.; Saleem, F.; Aslam, F.; Naz, S.

    2016-01-01

    Objective: To determine the residing microbial flora of ethylene oxide (EtO) sterilized medical devices and optimization of safe dose of gamma radiation (Cobalt 60 source) for the complete elimination of microbial load. Study Design: Experimental study. Place and Duration of Study: Department of Biotechnology, Lahore College for Women University, Lahore, Pakistan from September 2014 to June 2015. Methodology: Thirty-six samples of EtO sterilized medical devices of same batch of three different companies were collected for this study. Isolation and enumeration of microbes were done by using different selective and differential media. Gram staining and biochemically characterization by API 20 (Bio Merieux, France) kit was done for identification of the microorganisms. The medical devices having high microbial load were sent to Pakistan Radiation Services (PARAS) for gamma irradiations at 3 different selected doses (20 KGy, 25 KGy, and 30 KGy). Result: Different types of Gram positive bacteria (Staphylococcus epidermidis, Staphylococcus aureus and Bacillus subtilis) were isolated from the EtO sterilized samples. Gram negative bacteria and fungi were not detected on these medical devices. Gamma irradiations Result showed that 30 KGy was optimized dose for complete elimination of microbial flora on endotracheal, Nelaton, and tracheostomy tubes. Conclusion: Gamma radiations (Co 60 source) effectively decontaminate the microbial flora on the equipment previously sterilized by the ethylene oxide gas; and 30 KGy is the optimized dose for all these medical devices. (author)

  19. Phthalocyanines with eight oligo(ethylene oxide) alkoxy units: thermotropic phase behavior, aggregate formation and ion complexation with redox-active ions

    NARCIS (Netherlands)

    Piet, D.P.; Verheij, H.J.; Zuilhof, H.

    2003-01-01

    The thermotropic phase behavior of phthalocyanines (Pc's) with eight oligo(ethylene oxide) alkoxy side chains has been investigated. An increase in the number of ethylene oxide units results in a decrease in the solid-to-mesophase and isotropization temperatures. The investigated compounds display a

  20. New Aptes Cross-linked Polymers from Poly(ethylene oxide)s and Cyanuric Chloride for Lithium Batteries

    Science.gov (United States)

    Tigelaar, Dean M.; Meador, Mary Ann B.; Kinder, James D.; Bennett, William R.

    2005-01-01

    A new series of polymer electrolytes for use as membranes for lithium batteries are described. Electrolytes were made by polymerization between cyanuric chloride and diamino-terminated poly(ethylene oxide)s, followed by cross-linking via a sol-gel process. Thermal analysis and lithium conductivity of freestanding polymer films were studied. The effects of several variables on conductivity were investigated, such as length of backbone PEO chain, length of branching PEO chain, extent of branching, extent of cross-linking, salt content, and salt counterion. Polymer films with the highest percentage of PEO were found to be the most conductive, with a maximum lithium conductivity of 3.9 x 10(exp -5) S/cm at 25 C. Addition of plasticizer to the dry polymers increased conductivity by an order of magnitude.

  1. Effect of succinonitrile on electrical, structural, optical, and thermal properties of [poly(ethylene oxide)-succinonitrile]/LiI–I2 redox-couple solid polymer electrolyte

    International Nuclear Information System (INIS)

    Gupta, Ravindra Kumar; Rhee, Hee-Woo

    2012-01-01

    Effect of succinonitrile on electrical, structural, optical, and thermal properties of [poly(ethylene oxide)-succinonitrile]/LiI–I 2 redox-couple solid polymer electrolyte is reported for the first time. For the poly(ethylene oxide)-succinonitrile blend-based electrolyte electrical conductivity was noted as high as ∼3 × 10 −4 S cm −1 at 25 °C, which is an order of magnitude higher than that of pure poly(ethylene oxide)-based electrolyte. It also exhibited relatively better pseudo-activation energy (∼0.08 eV). X-ray diffractometry, polarized optical microscopy, and differential scanning calorimetry studies revealed that succinonitrile is helpful in reducing the poly(ethylene oxide) crystallinity due to its plasticizing property. FT-IR study showed significant modification of the poly(ethylene oxide) chain conformation due to the succinonitrile.

  2. A study on optical properties of poly (ethylene oxide) based polymer electrolyte with different alkali metal iodides

    Science.gov (United States)

    Rao, B. Narasimha; Suvarna, R. Padma

    2016-05-01

    Polymer electrolytes were prepared by adding poly (ethylene glycol) dimethyl ether (PEGDME), TiO2 (nano filler), different alkali metal iodide salts RI (R+=Li+, Na+, K+, Rb+, Cs+) and I2 into Acetonitrile gelated with Poly (ethylene oxide) (PEO). Optical properties of poly (ethylene oxide) based polymer electrolytes were studied by FTIR, UV-Vis spectroscopic techniques. FTIR spectrum reveals that the alkali metal cations were coordinated to ether oxygen of PEO. The optical absorption studies were made in the wavelength range 200-800 nm. It is observed that the optical absorption increases with increase in the radius of alkali metal cation. The optical band gap for allowed direct transitions was evaluated using Urbach-edges method. The optical properties such as optical band gap, refractive index and extinction coefficient were determined. The studied polymer materials are useful for solar cells, super capacitors, fuel cells, gas sensors etc.

  3. Ni–Ta–O mixed oxide catalysts for the low temperature oxidative dehydrogenation of ethane to ethylene

    KAUST Repository

    Zhu, Haibo

    2015-09-01

    The "wet" sol-gel and "dry" solid-state methods were used to prepare Ni-Ta-O mixed oxide catalysts. The resulting Ni-Ta oxides exhibit high activity and selectivity for the low temperature oxidative dehydrogenation of ethane to ethylene. The Ta/(Ni + Ta) atomic ratios (varying from 0 to 0.11 in "wet" sol-gel method, and from 0 to 0.20 in "dry" solid-state method) as well as the preparation methods used in the synthesis, play important roles in controlling catalyst structure, activity, selectivity and stability in the oxidative dehydrogenation of ethane. Electron microscopy characterizations (TEM, EELS mapping, and HAADF-STEM) clearly demonstrate that the Ta atoms are inserted into NiO crystal lattice, resulting in the formation of a new Ni-Ta oxide solid solution. More Ta atoms are found to be located at the lattice sites of crystal surface in sol-gel catalyst. While, a small amount of thin layer of Ta2O5 clusters are detected in solid-state catalyst. Further characterization by XRD, N2 adsorption, SEM, H2-TPR, XPS, and Raman techniques reveal different properties of these two Ni-Ta oxides. Due to the different properties of the Ni-Ta oxide catalysts prepared by two distinct approaches, they exhibit different catalytic behaviors in the ethane oxidative dehydrogenation reaction at low temperature. Thus, the catalytic performance of Ni-Ta-O mixed oxide catalysts can be systematically modified and tuned by selecting a suitable synthesis method, and then varying the Ta content. ©2015 Elsevier Inc. All rights reserved.

  4. The effect of gamma-ray and ethylene oxide sterilization on collagen-based wound-repair materials

    International Nuclear Information System (INIS)

    Gorham, S.D.; Scott, R.

    1993-01-01

    The effects of 2.5, 5.0, 7.5 and 10 Mrad gamma-irradiation and ethylene oxide sterilization on collagen-coated vicryl mesh, on collagen film and vicryl mesh were investigated. No cytotoxic effects were observed towards either L929 cells or human fibroblasts with any of the treatments, even at the highest doses of irradiation. Although the rate of biodegradation and tissue reaction towards the test materials appeared to be relatively unaffected by ethylene oxide, the rate of breakdown in the lumbar muscles of laboratory rats was considerably increased by irradiation. Dose-dependent irradiation damage to the vicryl mesh was confirmed in vitro using viscometry and by an increase in the rate of hydrolysis in phosphate-buffered saline (PBS) at 37 o C. Tensiometric studies on irradiated collagen films showed a dose-dependent reduction in both the break load and elongation before breaking. A small reduction in the break load and stretch to breaking was also observed following treatment with ethylene oxide. The findings presented favour ethylene oxide as a method of sterilization of both the composite membrane and its individual components. However, gamma-irradiation produced no toxic effects or adverse tissue reaction under the conditions described, and is more convenient to use. Hence, provided that the efficacy of the membrane would not be compromised by the higher rate of degradation, it could also be considered for sterilization of the material. (author)

  5. Cadmium toxicity in cultured tomato cells - Role of ethylene, proteases and oxidative stress in cell death signaling

    NARCIS (Netherlands)

    Iakimova, E.T.; Woltering, E.J.; Kapchina-Toteva, V.M.; Harren, F.J.M.; Cristescu, S.M.

    2008-01-01

    Our aim was to investigate the ability of cadmium to induce programmed cell death in tomato suspension cells and to determine the involvement of proteolysis, oxidative stress and ethylene. Tomato suspension cells were exposed to treatments with CdSO4 and cell death was calculated after fluorescein

  6. High-efficiency synthesis of dendrimer-like poly(ethylene oxide) via “arm-first” approach

    KAUST Repository

    Zhu, Saisai; Xia, Ru; Chen, Peng; Yang, Bin; Miao, Jibin; Zheng, Zhengzhi; Su, Lifeng; Qian, Jiasheng; Cao, Ming; Feng, Xiaoshuang

    2017-01-01

    In this study, a dendrimer-like polymer based on poly(ethylene oxide) (PEO) was synthesized through a combination of anionic ring-opening polymerization (AROP) and click reaction via arm-first method. Firstly, the polymeric arm, a linear PEO

  7. Phosphazene-promoted metal-free ring-opening polymerization of ethylene oxide initiated by carboxylic acid

    KAUST Repository

    Zhao, Junpeng; Pahovnik, David; Gnanou, Yves; Hadjichristidis, Nikolaos

    2014-01-01

    The effectiveness of carboxylic acid as initiator for the anionic ring-opening polymerization of ethylene oxide was investigated with a strong phosphazene base (t-BuP4) used as promoter. Kinetic study showed an induction period, i.e., transformation

  8. High molecular weight poly(L-lactide) and poly(ethylene oxide) blends : Thermal characterization and physical properties

    NARCIS (Netherlands)

    Nijenhuis, AJ; Colstee, E; Grijpma, DW; Pennings, AJ

    1996-01-01

    The miscibility of high molecular weight poly(L-lactide) (PLLA) with high molecular weight poly(ethylene oxide) (PEG) was studied by differential scanning calorimetry. Ail blends containing up to 50 weight% PEO showed single glass transition temperatures. The PLLA and PEO melting temperatures were

  9. Effects of Silica Nanostructures in Poly(ethylene oxide)-Based Composite Polymer Electrolytes.

    Science.gov (United States)

    Mohanta, Jagdeep; Anwar, Shahid; Si, Satyabrata

    2016-06-01

    The present work describes the synthesis of some poly(ethylene oxide)-based nanocomposite polymer electrolyte films using various silica nanostructures as the inorganic filler by simple solution mixing technique, in which the nature of the silica nanostructures play a vital role in modulating their electrochemical performances at room temperature. The silica nanostructures are prepared by ammonical hydrolysis of tetraethyl orthosilicate following the modified St6ber method. The resulting films are characterized by X-ray diffraction and differential scanning calorimeter to study their crystallinity. Room temperature AC impedance spectroscopy is utilized to determine the Li+ ion conductivity of the resulting films. The observed conductivity values of various NCPE films depend on the nature of silica filling as well as on their surface characteristics and also on the varying PEO-Li+ ratio, which is observed to be in the order of 10(-7)-10(-6) S cm(-1).

  10. Poly(ester amide-Poly(ethylene oxide Graft Copolymers: Towards Micellar Drug Delivery Vehicles

    Directory of Open Access Journals (Sweden)

    Gregory J. Zilinskas

    2012-01-01

    Full Text Available Micelles formed from amphiphilic copolymers are promising materials for the delivery of drug molecules, potentially leading to enhanced biological properties and efficacy. In this work, new poly(ester amide-poly(ethylene oxide (PEA-PEO graft copolymers were synthesized and their assembly into micelles in aqueous solution was investigated. It was possible to tune the sizes of the micelles by varying the PEO content of the polymers and the method of micelle preparation. Under optimized conditions, it was possible to obtain micelles with diameters less than 100 nm as measured by dynamic light scattering and transmission electron microscopy. These micelles were demonstrated to encapsulate and release a model drug, Nile Red, and were nontoxic to HeLa cells as measured by an MTT assay. Overall, the properties of these micelles suggest that they are promising new materials for drug delivery systems.

  11. Adsorption of poly(ethylene oxide) on smectite: Effect of layer charge.

    Science.gov (United States)

    Su, Chia-Chi; Shen, Yun-Hwei

    2009-04-01

    The adsorption of polymers on clay is important in many applications. However the mechanisms of poly(ethylene oxide) (PEO) adsorption on smectite is not well elucidated at present. The aim of this study was to investigate the effect of layer charge density on the adsorption of PEO by smectite. The results indicated that both the hydrophobic interaction (between CH(2)CH(2) groups and siloxane surface) and the hydrogen bonding (between ether oxygen of PEO and structure OH of smectite) lead to PEO preferential adsorption on the surface of low-charge smectite. In addition, the delamination of low-charge smectite in water is enhanced upon PEO adsorption presumably due to the hydrophilic ether oxygen of adsorbed PEO.

  12. Effect Of Ethylene Oxide, Autoclave and Ultra Violet Sterilizations On Surface Topography Of Pet Electrospun Fibers

    Directory of Open Access Journals (Sweden)

    Sebnem DUZYER

    2016-11-01

    Full Text Available The aim of this study to investigate the effects of different sterilization methods on electrospun polyester. Ethylene oxide (EO, autoclave (AU and ultraviolet (UV sterilization methods were applied to electrospun fibers produced from polyethylene terephthalate (PET solutions with concentrations of 10, 15 and 20 wt.%. The surface characteristics of the fibers were examined by scanning electron microscope (SEM, atomic force microscope (AFM, surface pore size studies and contact angle measurements. Differential scanning calorimetry (DSC tests were carried out to characterize the thermal properties. Fourier Transform Infrared spectroscopy (FTIR tests were performed to analyze the micro structural properties. SEM studies showed that different sterilization methods made significant changes on the surfaces of the fibers depending on the PET concentration. Although the effects were decreased with the increasing polymer concentration, the fiber structure was damaged especially with the EO sterilization. The contact angle values were decreased with the UV sterilization method the most.

  13. Thermodynamic characterization of poly(4-hydroxystyrene)-g-[poly(propyleneoxide-b-ethylene oxide)] thermoresponsive brush copolymers

    Energy Technology Data Exchange (ETDEWEB)

    Thanassoulas, Angelos, E-mail: athanas@rrp.demokritos.gr [Biomolecuar Physics Laboratory, National Centre for Scientific Research “Demokritos”, 153 10 Aghia Paraskevi (Greece); Papadopoulos, Athanasios [Biomolecuar Physics Laboratory, National Centre for Scientific Research “Demokritos”, 153 10 Aghia Paraskevi (Greece); Pispas, Stergios [Theoretical and Physical Chemistry Institute, National Hellenic Research Foundation, 11635 Athens (Greece); Zhao, Junpeng; Zhang, Guangzhao [Faculty of Materials Science and Engineering, South China University of Technology, Guangzhou 510640 (China); Nounesis, George [Biomolecuar Physics Laboratory, National Centre for Scientific Research “Demokritos”, 153 10 Aghia Paraskevi (Greece)

    2016-08-20

    Highlights: • PPO-b-PEO core-shell brush copolymers exhibit thermoresponsive behavior in aqueous solutions. • Their thermal transitions strongly depend on their architecture and chemical composition. • These copolymer transitions follow a coil-to-globule mechanism. • It is possible to fine-tune their thermoresponsiveness to a wide range of temperatures. - Abstract: Thermoresponsive brush copolymers with poly(4-hydroxystyrene) backbones and poly(propyleneoxide-b-ethylene oxide) side chains were synthesized via a “grafting from” technique. The thermoresponsive behavior of four samples with different compositions has been investigated in dilute aqueous solutions by high-accuracy differential scanning calorimetry measurements. Thermal transitions involving both core contraction and intermolecular aggregation have been observed for all the copolymers in this study. The temperature where these thermal transitions occur is strongly associated to the architecture and chemical composition of the copolymers, allowing for fine-tuning of their thermoresponsiveness in a wide range of temperatures.

  14. Nanostructure of propylammonium nitrate in the presence of poly(ethylene oxide) and halide salts

    Science.gov (United States)

    Stefanovic, Ryan; Webber, Grant B.; Page, Alister J.

    2018-05-01

    Nanoscale structure of protic ionic liquids is critical to their utility as molecular electrochemical solvents since it determines the capacity to dissolve salts and polymers such as poly(ethylene oxide) (PEO). Here we use quantum chemical molecular dynamics simulations to investigate the impact of dissolved halide anions on the nanostructure of an archetypal nanostructured protic ionic liquid, propylammonium nitrate (PAN), and how this impacts the solvation of a model PEO polymer. At the molecular level, PAN is nanostructured, consisting of charged/polar and uncharged/nonpolar domains. The charged domain consists of the cation/anion charge groups, and is formed by their electrostatic interaction. This domain solvophobically excludes the propyl chains on the cation, which form a distinct, self-assembled nonpolar domain within the liquid. Our simulations demonstrate that the addition of Cl- and Br- anions to PAN disrupts the structure within the PAN charged domain due to competition between nitrate and halide anions for the ammonium charge centre. This disruption increases with halide concentration (up to 10 mol. %). However, at these concentrations, halide addition has little effect on the structure of the PAN nonpolar domain. Addition of PEO to pure PAN also disrupts the structure within the charged domain of the liquid due to hydrogen bonding between the charge groups and the terminal PEO hydroxyl groups. There is little other association between the PEO structure and the surrounding ionic liquid solvent, with strong PEO self-interaction yielding a compact, coiled polymer morphology. Halide addition results in greater association between the ionic liquid charge centres and the ethylene oxide components of the PEO structure, resulting in reduced conformational flexibility, compared to that observed in pure PAN. Similarly, PEO self-interactions increase in the presence of Cl- and Br- anions, compared to PAN, indicating that the addition of halide salts to PAN

  15. Removal of ethylene from air stream by adsorption and plasma-catalytic oxidation using silver-based bimetallic catalysts supported on zeolite.

    Science.gov (United States)

    Trinh, Quang Hung; Lee, Sang Baek; Mok, Young Sun

    2015-03-21

    Dynamic adsorption of ethylene on 13X zeolite-supported Ag and Ag-M(x)O(y) (M: Co, Cu, Mn, and Fe), and plasma-catalytic oxidation of the adsorbed ethylene were investigated. The experimental results showed that the incorporation of Ag into zeolite afforded a marked enhancement in the adsorptivity for ethylene. The addition of transition metal oxides was found to have a positive influence on the ethylene adsorption, except Fe(x)O(y). The presence of the additional metal oxides, however, appeared to somewhat interrupt the diffusion of ozone into the zeolite micro-pores, leading to a decrease in the plasma-catalytic oxidation efficiency of the ethylene adsorbed there. Among the second additional metal oxides, Fe(x)O(y) was able to reduce the emission of ozone during the plasma-catalytic oxidation stage while keeping a high effectiveness for the oxidative removal of the adsorbed ethylene. The periodical treatment consisting of adsorption followed by plasma-catalytic oxidation may be a promising energy-efficient ethylene abatement method. Copyright © 2014 Elsevier B.V. All rights reserved.

  16. Poly(ethylene glycol or Poly(ethylene oxide?: Magnitude of end-group Contribution to the Partitioning of Ethylene Oxide Oligomers and Polymers between Water and Organic Phases

    Directory of Open Access Journals (Sweden)

    Spitzer Marcos

    2002-01-01

    Full Text Available PEO partitioning from water to CH2Cl2 and CHCl3 increases with its molar mass, leveling off at ca. 3 000 g mol-1. Such a behaviour is related to PEO end-group contributions, suggesting a polyglycol to polyether transition at ca. 3 000 g mol-1.

  17. Poly(ethylene glycol) dicarboxylate/poly(ethylene oxide) hydrogel film co-crosslinked by electron beam irradiation as an anti-adhesion barrier

    International Nuclear Information System (INIS)

    Haryanto,; Singh, Deepti; Han, Sung Soo; Son, Jun Hyuk; Kim, Seong Cheol

    2015-01-01

    The cross-linked poly(ethylene glycol) dicarboxylate (PEGDC)/poly(ethylene oxide) (PEO) and poly(ethylene glycol) dimethacrylate (PEGDMA)/(PEO) hydrogels were developed for possible biomedical applications such as an anti-adhesion barrier. Various contents of PEGDC/PEO film were irradiated using an electron beam with various beam intensities in order to obtain various degrees of crosslinked hydrogels. The optimum dose (300 kGy) and total crosslinker content of 10% were used to prepare crosslinked hydrogel films with three different compositions (10% PEGDC, 10% PEGDMA, 5% PEGDC–5% PEGDMA). Among them, 10% PEGDC hydrogel film exhibited the highest elongation at break (69.33 ± 6.87%) with high mechanical strength. 10% PEGDC hydrogel film showed the lowest hemolysis activity (6.03 ± 0.01%) and the highest tissue adherence (75.67 ± 1.15 cN). The result also indicated that the carboxyl groups in PEGDC affect the tissue adherence of hydrogel films via H-bonding interactions. In animal studies, 10% PEGDC anti-adhesion hydrogel film degraded within 3 weeks and demonstrated better anti-adhesive effect compared to Guardix-SG®. - Highlights: • The crosslinked PEGDC/PEO hydrogel was developed by e-beam irradiation. • 10% PEGDC hydrogel film showed the highest elongation at break and tissue adhesion. • The COOH group enhanced the tissue adherence of hydrogel films on the intestine. • 10% PEGDC hydrogel film demonstrated a good anti-adhesive effect in animal study. • All of the hydrogel films with 10% PEGDC degraded in vivo within three weeks

  18. Citric acid-modified Fenton's reaction for the oxidation of chlorinated ethylenes in soil solution systems.

    Science.gov (United States)

    Seol, Yongkoo; Javandel, Iraj

    2008-06-01

    Fenton's reagent, a solution of hydrogen peroxide and ferrous iron catalyst, is used for an in situ chemical oxidation of organic contaminants. Sulfuric acid is commonly used to create an acidic condition needed for catalytic oxidation. Fenton's reaction often involves pressure buildup and precipitation of reaction products, which can cause safety hazards and diminish efficiency. We selected citric acid, a food-grade substance, as an acidifying agent to evaluate its efficiencies for organic contaminant removal in Fenton's reaction, and examined the impacts of using citric acid on the unwanted reaction products. A series of batch and column experiments were performed with varying H2O2 concentrations to decompose selected chlorinated ethylenes. Either dissolved iron from soil or iron sulfate salt was added to provide the iron catalyst in the batch tests. Batch experiments revealed that both citric and sulfuric acid systems achieved over 90% contaminant removal rates, and the presence of iron catalyst was essential for effective decontamination. Batch tests with citric acid showed no signs of pressure accumulation and solid precipitations, however the results suggested that an excessive usage of H2O2 relative to iron catalysts (Fe2+/H2O2<1/330) would result in lowering the efficiency of contaminant removal by iron chelation in the citric acid system. Column tests confirmed that citric acid could provide suitable acidic conditions to achieve higher than 55% contaminant removal rates.

  19. Oxygen Barrier Properties and Melt Crystallization Behavior of Poly(ethylene terephthalate/Graphene Oxide Nanocomposites

    Directory of Open Access Journals (Sweden)

    Anna Szymczyk

    2015-01-01

    Full Text Available Poly(ethylene terephthalate nanocomposites with low loading (0.1–0.5 wt% of graphene oxide (GO have been prepared by using in situ polymerization method. TEM study of nanocomposites morphology has shown uniform distribution of highly exfoliated graphene oxide nanoplatelets in PET matrix. Investigations of oxygen permeability of amorphous films of nanocomposites showed that the nanocomposites had better oxygen barrier properties than the neat PET. The improvement of oxygen permeability for PET nanocomposite films over the neat PET is approximately factors of 2–3.3. DSC study on the nonisothermal crystallization behaviors proves that GO acts as a nucleating agent to accelerate the crystallization of PET matrix. The evolution of the lamellar nanostructure of nanocomposite and neat PET was monitored by SAXS during nonisothermal crystallization from the melt. It was found that unfilled PET and nanocomposite with the highest concentration of GO (0.5 wt% showed almost similar values of the long period (L=11.4 nm for neat PET and L=11.5 nm for PET/0.5GO.

  20. Final Technical Report - High-Performance, Oxide-Dispersion-Strengthened Tubes for Production of Ethylene adn Other Industrial Chemicals

    Energy Technology Data Exchange (ETDEWEB)

    McKimpson, Marvin G.

    2006-04-06

    This project was undertaken by Michigan Technological University and Special Metals Corporation to develop creep-resistant, coking-resistant oxide-dispersion-strengthened (ODS) tubes for use in industrial-scale ethylene pyrolysis and steam methane reforming operations. Ethylene pyrolysis tubes are exposed to some of the most severe service conditions for metallic materials found anywhere in the chemical process industries, including elevated temperatures, oxidizing atmospheres and high carbon potentials. During service, hard deposits of carbon (coke) build up on the inner wall of the tube, reducing heat transfer and restricting the flow of the hydrocarbon feedstocks. About every 20 to 60 days, the reactor must be taken off-line and decoked by burning out the accumulated carbon. This decoking costs on the order of $9 million per year per ethylene plant, accelerates tube degradation, and requires that tubes be replaced about every 5 years. The technology developed under this program seeks to reduce the energy and economic cost of coking by creating novel bimetallic tubes offering a combination of improved coking resistance, creep resistance and fabricability not available in current single-alloy tubes. The inner core of this tube consists of Incoloy(R) MA956, a commercial ferritic Fe-Cr-Al alloy offering a 50% reduction in coke buildup combined with improved carburization resistance. The outer sheath consists of a new material - oxide dispersion strengthened (ODS) Alloy 803(R) developed under the program. This new alloy retains the good fireside environmental resistance of Alloy 803, a commercial wrought alloy currently used for ethylene production, and provides an austenitic casing to alleviate the inherently-limited fabricability of the ferritic Incoloy(R) MA956 core. To provide mechanical compatibility between the two alloys and maximize creep resistance of the bimetallic tube, both the inner Incoloy(R) MA956 and the outer ODS Alloy 803 are oxide dispersion

  1. Synthesis of terephthalic acid via Diels-Alder reactions with ethylene and oxidized variants of 5-hydroxymethylfurfural

    Science.gov (United States)

    Pacheco, Joshua J.; Davis, Mark E.

    2014-01-01

    Terephthalic acid (PTA), a monomer in the synthesis of polyethylene terephthalate (PET), is obtained by the oxidation of petroleum-derived p-xylene. There is significant interest in the synthesis of renewable, biomass-derived PTA. Here, routes to PTA starting from oxidized products of 5-hydroxymethylfurfural (HMF) that can be produced from biomass are reported. These routes involve Diels-Alder reactions with ethylene and avoid the hydrogenation of HMF to 2,5-dimethylfuran. Oxidized derivatives of HMF are reacted with ethylene over solid Lewis acid catalysts that do not contain strong Brønsted acids to synthesize intermediates of PTA and its equally important diester, dimethyl terephthalate (DMT). The partially oxidized HMF, 5-(hydroxymethyl)furoic acid (HMFA), is reacted with high pressure ethylene over a pure-silica molecular sieve containing framework tin (Sn-Beta) to produce the Diels-Alder dehydration product, 4-(hydroxymethyl)benzoic acid (HMBA), with 31% selectivity at 61% HMFA conversion after 6 h at 190 °C. If HMFA is protected with methanol to form methyl 5-(methoxymethyl)furan-2-carboxylate (MMFC), MMFC can react with ethylene in the presence of Sn-Beta for 2 h to produce methyl 4-(methoxymethyl)benzenecarboxylate (MMBC) with 46% selectivity at 28% MMFC conversion or in the presence of a pure-silica molecular sieve containing framework zirconium (Zr-Beta) for 6 h to produce MMBC with 81% selectivity at 26% MMFC conversion. HMBA and MMBC can then be oxidized to produce PTA and DMT, respectively. When Lewis acid containing mesoporous silica (MCM-41) and amorphous silica, or Brønsted acid containing zeolites (Al-Beta), are used as catalysts, a significant decrease in selectivity/yield of the Diels-Alder dehydration product is observed. PMID:24912153

  2. Doxorubicin-loaded micelles of reverse poly(butylene oxide)-poly(ethylene oxide)-poly(butylene oxide) block copolymers as efficient "active" chemotherapeutic agents.

    Science.gov (United States)

    Cambón, A; Rey-Rico, A; Mistry, D; Brea, J; Loza, M I; Attwood, D; Barbosa, S; Alvarez-Lorenzo, C; Concheiro, A; Taboada, P; Mosquera, V

    2013-03-10

    Five reverse poly(butylene oxide)-poly(ethylene oxide)-poly(butylene oxide) block copolymers, BOnEOmBOn, with BO ranging from 8 to 21 units and EO from 90 to 411 were synthesized and evaluated as efficient chemotherapeutic drug delivery nanocarriers and inhibitors of the P-glycoprotein (P-gp) efflux pump in a multidrug resistant (MDR) cell line. The copolymers were obtained by reverse polymerization of poly(butylene oxide), which avoids transfer reaction and widening of the EO block distribution, commonly found in commercial poly(ethylene oxide)-poly(propylene oxide) block copolymers (poloxamers). BOnEOmBOn copolymers formed spherical micelles of 10-40 nm diameter at lower concentrations (one order of magnitude) than those of equivalent poloxamers. The influence of copolymer block lengths and BO/EO ratios on the solubilization capacity and protective environment for doxorubicin (DOXO) was investigated. Micelles showed drug loading capacity ranging from ca. 0.04% to 1.5%, more than 150 times the aqueous solubility of DOXO, and protected the cargo from hydrolysis for more than a month due to their greater colloidal stability in solution. Drug release profiles at various pHs, and the cytocompatibility and cytotoxicity of the DOXO-loaded micelles were assessed in vitro. DOXO loaded in the polymeric micelles accumulated more slowly inside the cells than free DOXO due to its sustained release. All copolymers were found to be cytocompatible, with viability extents larger than 95%. In addition, the cytotoxicity of DOXO-loaded micelles was higher than that observed for free drug solutions in a MDR ovarian NCI-ADR-RES cell line which overexpressed P-gp. The inhibition of the P-gp efflux pump by some BOnEOmBOn copolymers, similar to that measured for the common P-gp inhibitor verapamil, favored the retention of DOXO inside the cell increasing its cytotoxic activity. Therefore, poly(butylene oxide)-poly(ethylene oxide) block copolymers offer interesting features as cell

  3. Adsorption of Poly(ethylene oxide)-Poly(lactide) Copolymers. Effects of Composition and Degradation.

    Science.gov (United States)

    Muller, Dries; Carlsson, Fredrik; Malmsten, Martin

    2001-04-01

    The effect of chemical degradation of two diblock copolymers of poly(ethylene oxide) (E) and poly(lactide) (L), E(39)L(5) and E(39)L(20), on their adsorption at silica and methylated silica was investigated with in situ ellipsometry. Steric stablization of polystyrene dispersions was investigated in relation to degradation. Hydrolysis of the poly(lactide) block of the copolymers was followed at different temperatures and pH by using HPLC to measure the occurrence of lactic acid in solution. The block copolymers were quite stable in pH-unadjusted solution at low temperature, whereas degradation was facilitated by increasing temperature or lowering of the pH. Lower degradation rates of E(39)L(20) where observed at low temperature in comparison with those of E(39)L(5), whereas the degradation rates of the copolymers were quantitatively similar at high temperature. The adsorption of the copolymers at methylated silica substrates decreased with increasing degree of degradation due to the reduction in the ability of hydrophobic block to anchor the copolymer layer at the surface. At silica the adsorption initially increased with increasing degradation, particularly for E(39)L(20) due to deposition of aggregates onto the surface. After extensive degradation the adsorption of the copolymers at both silica and methylated silica resembled that of the corresponding poly(ethylene oxide) homopolymer. Overall, it was found that the eventual reduction in adsorption occurred at a lower degree of degradation for E(39)L(5) than for E(39)L(20). Mean-field calculations showed a reduced anchoring for the block copolymers with decreasing poly(lactide) block length at hydrophobic surfaces. In accordance with this finding, it was observed that polystyrene dispersions were stabilized by E(39)L(20) or E(39)L(5) in a way that depended on both the lactide block length and the degree of degradation. Upon degradation of the hydrophobic block, stabilization of the polystyrene dispersions was

  4. Catalysis by Nanostructures: Methane, Ethylene Oxide, and Propylene Oxide Synthesis on Ag, Cu or Au Nanoclusters

    Science.gov (United States)

    2008-02-07

    22 nm) were prepared by reducing a Au salt, and encapsulating the Au nanoparticles formed in a polymer33 . A variety of high area oxides (TiO 2, ZnO ...Morphologies Utilizing a Combinatorial Electrochemistry Methodology. Ph. D. dissertation, Chemical Engineering, University of California, Santa Barbara (2004

  5. Phosphazene-promoted metal-free ring-opening polymerization of ethylene oxide initiated by carboxylic acid

    KAUST Repository

    Zhao, Junpeng

    2014-03-11

    The effectiveness of carboxylic acid as initiator for the anionic ring-opening polymerization of ethylene oxide was investigated with a strong phosphazene base (t-BuP4) used as promoter. Kinetic study showed an induction period, i.e., transformation of carboxylic acid to hydroxyl ester, followed by slow chain growth together with simultaneous and fast end-group transesterification, which led to poly(ethylene oxide) (PEO) consisting of monoester (monohydroxyl), diester, and dihydroxyl species. An appropriate t-BuP4/acid ratio was proven to be essential to achieve better control over the polymerization and low dispersity of PEO. This work provides important information and enriches the toolbox for macromolecular and biomolecular engineering with protic initiating sites. © 2014 American Chemical Society.

  6. Analysis of hemoglobin adducts from acrylamide, glycidamide, and ethylene oxide in paired mother/cord blood samples from Denmark

    DEFF Research Database (Denmark)

    von Stedingk, Hans; Vikström, Anna C; Rydberg, Per

    2011-01-01

    The knowledge about fetal exposure to acrylamide/glycidamide from the maternal exposure through food is limited. Acrylamide, glycidamide, and ethylene oxide are electrophiles and form adducts with hemoglobin (Hb), which could be used for in vivo dose measurement. In this study, a method.......20-0.73) for glycidamide, and 0.43 (range 0.17-1.34) for ethylene oxide. In vitro studies with acrylamide and glycidamide showed a lower (0.38-0.48) rate of adduct formation with Hb in cord blood than with Hb in maternal blood, which is compatible with the structural differences in fetal and adult Hb. Together...... for analysis of Hb adducts by liquid chromatography-mass spectrometry, the adduct FIRE procedure, was applied to measurements of adducts from these compounds in maternal blood samples (n = 87) and umbilical cord blood samples (n = 219). The adduct levels from the three compounds, acrylamide, glycidamide...

  7. Dynamics of electrocatalytic oxidation of ethylene glycol, methanol and formic acid at MWCNT platform electrochemically modified with Pt/Ru nanoparticles

    CSIR Research Space (South Africa)

    Maxakato, NW

    2010-03-01

    Full Text Available Comparative electrocatalytic behavior of functionalized multiwalled carbon nanotubes (fMWCNTs) electrodecorated with Pt/Ru nanoparticles towards the oxidation of methanol (MeOH), ethylene glycol (EG) and formic acid (FA) has been investigated...

  8. In vitro degradation of nanoparticles prepared from polymers based on DL-lactide, glycolide and poly(ethylene oxide)

    NARCIS (Netherlands)

    Zweers, M.L.T.; Engbers, G.H.M.; Grijpma, Dirk W.; Feijen, Jan

    2004-01-01

    Nanoparticles of poly(DL-lactic acid) (PDLLA), poly(DL-lactic-co-glycolic acid) (PLGA) and poly(ethylene oxide)–PLGA diblock copolymer (PEO–PLGA) were prepared by the salting-out method. The in vitro degradation of PDLLA, PLGA and PEO–PLGA nanoparticles in PBS (pH 7.4) at 37 °C was studied. The

  9. Poly(ethylene oxide) layers grafted to dopamine-melanin anchoring layer: stability and resistance to protein adsorption

    Czech Academy of Sciences Publication Activity Database

    Pop-Georgievski, Ognen; Popelka, Štěpán; Houska, Milan; Chvostová, Dagmar; Proks, Vladimír; Rypáček, František

    2011-01-01

    Roč. 12, č. 9 (2011), s. 3232-3242 ISSN 1525-7797 R&D Projects: GA AV ČR KJB400500904; GA ČR GAP108/11/1857; GA ČR GPP207/10/P569 Institutional research plan: CEZ:AV0Z40500505; CEZ:AV0Z10100522 Keywords : dopamine -melanin * polydopamine * poly(ethylene oxide) Subject RIV: CD - Macromolecular Chemistry Impact factor: 5.479, year: 2011

  10. Crystallinity and order of poly(ethylene oxide)/lithium triflate complex confined in nanoporous membranes

    International Nuclear Information System (INIS)

    Bishop, Christina; Teeters, Dale

    2009-01-01

    The confinement of poly(ethylene oxide), PEO, electrolyte in pores of 13, 35, 55 and 100 nm in diameter in nanoporous alumina membranes was seen to have effects on the ionic conduction properties. Specific conductivity values for the PEO/lithium triflate complex in the 13 and 35 nm pores, for temperatures below the melt temperatures, were increased by a factor of four compared to the non-confined polymer and the 55 and 100 nm pore systems. Thermal analysis data indicate the melting temperature for the PEO electrolyte in the pores is directly proportional to the pore size such that as the pore size of confinement is decreased, the T m decreases as well. The same behavior is seen for the amount of crystallinity, with less crystallinity being observed as the pores become smaller. Perhaps the observed conduction behavior could be attributed to less crystallinity. However, it is known that confinement of polyethers in pores results in stretching and ordering of the backbone and that such ordering can increase ion conduction. This ordering would seem to be the major factor involved in these results. The enhanced conduction only being seen in the 13 and 35 nm pores and not the 55 and 100 nm pores is attributed to the larger size for the latter which allows a more bulk-like behavior with less ordering.

  11. Poly(ethylene oxide)/clay nanaocomposites: Thermal and mechanical properties

    International Nuclear Information System (INIS)

    Ejder-Korucu, Mehtap; Gürses, Ahmet; Karaca, Semra

    2016-01-01

    Highlights: • PEO/clay nanocomposites were prepared via solution intercalation. Complete exfoliation occurs in samples of 0.5 and 2.0 CEC. • The impaired helical structure of PEO in nanocomposite structures had been verified based on the results of FTIR studies. • The crystallization temperature of PEO/OMMT nanocomposites is low compared to raw polymer. • The increase of melting temperatures indicates the increase of the stability of PEO in case of availability of clay. • The tensile strength, yield strength, % stretching of nanocomposite samples increase compared to raw polymer at all CEC rates. - Abstract: Poly(ethylene oxide) (PEO)/clay nanocomposites were prepared by a solution intercalation method using chloroform as a solvent. The nanocomposites were characterised by X-ray diffraction (XRD), scanning electron microscopy (SEM), differential scanning calorimetry (DSC), Fourier transform infrared spectroscopy (FT-IR) and also investigation of some mechanical properties of the composites. Formation of nanocomposite was confirmed by XRD analysis. The increasing tendency of exfoliation degree with an increase in clay content may be attributed to easier diffusion of PEO chains to interlayer regions. An increase in PEO crystallinity in case of nanocomposite, was confirmed by an increase in the heat of melting as indicated by DSC. Improvement in tensile properties in all respect was observed for nanocomposites with clay content.

  12. Resistance of poly(ethylene oxide)-silane monolayers to the growth of polyelectrolyte multilayers.

    Science.gov (United States)

    Buron, Cédric C; Callegari, Vincent; Nysten, Bernard; Jonas, Alain M

    2007-09-11

    The ability of poly(ethylene oxide)-silane (PEO-silane) monolayers grafted onto silicon surfaces to resist the growth of polyelectrolyte multilayers under various pH conditions is assessed for different pairs of polyelectrolytes of varying molar mass. For acidic conditions (pH 3), the PEO-silane monolayers exhibit good polyelectrolyte repellency provided the polyelectrolytes bear no moieties that are able to form hydrogen bonds with the ether groups of the PEO chains. At basic pH, PEO-silane monolayers undergo substantial hydrolysis leading to the formation of negatively charged defects in the monolayers, which then play the role of adsorption sites for the polycation. Once the polycation is adsorbed, multilayer growth ensues. Because this is defect-driven growth, the multilayer is not continuous and is made of blobs or an open network of adsorbed strands. For such conditions, the molar mass of the polyelectrolyte plays a key role, with polyelectrolyte chains of larger molar mass adsorbing on a larger number of defects, resulting in stronger anchoring of the polyelectrolyte complex on the surfaces and faster subsequent growth of the multilayer. For polyelectrolytes of sufficiently low molar mass at pH 9, the growth of the multilayer can nevertheless be prevented for as much as five cycles of deposition.

  13. Crystallization and unusual rheological behavior in poly(ethylene oxide)–clay nanocomposites

    KAUST Repository

    Kelarakis, Antonios

    2011-05-01

    We report a systematic study of the crystallization and rheological behavior of poly(ethylene oxide) (PEO)-clay nanocomposites. To that end a series of nanocomposites based on PEOs of different molecular weight (103 < MW < 105 g/mol) and clay surface modifier was synthesized and characterized. Incorporation of organoclays with polar (MMT-OH) or aromatic groups (MMT-Ar) suppresses the crystallization of polymer chains in low MW PEO, but does not significantly affect the crystallization of high MW matrices. In addition, the relative complex viscosity of the nanocomposites based on low MW PEO increases significantly, but the effect is less pronounced at higher MWs. The viscosity increases in the series MMT-Alk < MMT-OH < MMT-Ar. In contrast to the neat PEO which exhibits a monotonic decrease of viscosity with temperature, all nanocomposites show an increase after a certain temperature. This is the first report of such dramatic enhancements in the viscoelasticity of nanocomposites, which are reversible, are based on a simple polymer matrix and are true in a wide temperature range. © 2011 Elsevier Ltd. All rights reserved.

  14. SHI induced modification in structural, optical, dielectric and thermal properties of poly ethylene oxide films

    Energy Technology Data Exchange (ETDEWEB)

    Patel, Gnansagar B.; Bhavsar, Shilpa [Department of Physics, The M.S. University of Baroda, Vadodara 390002 (India); Singh, N.L., E-mail: nl.singh-phy@msubaroda.ac.in [Department of Physics, The M.S. University of Baroda, Vadodara 390002 (India); Singh, F.; Kulriya, P.K. [Inter University Accelerator Centre, Aruna Asaf Ali Marg, New Delhi 110067 (India)

    2016-07-15

    Poly ethylene oxide (PEO) films were synthesized by solution cast method. These self-standing films were exposed with 60 MeV C{sup +5} ion and 100 MeV Ni{sup +7} ion at different fluences. SHI induced effect was investigated by employing various techniques. The crystalline size decreased upon irradiation as observed from XRD analysis. FTIR analysis reveals the decrement in the peak intensity upon irradiation. Tauc’s method was used to determine the optical band gap (E{sub g}), which shows decreasing trends with increase of fluence. The dielectric properties were investigated in the frequency range 10 Hz to 10 MHz for unirradiated and irradiated films. The dielectric constant remains same for the broad-spectrum of frequency and increases at lower frequency. The dielectric loss also moderately influence as a function of frequency due to irradiation. DSC analysis validated the results of XRD. Scanning electron microscopy (SEM) reveals that there is significant change in the surface morphology due to irradiation.

  15. Electrospinning of chitosan solutions in acetic acid with poly(ethylene oxide).

    Science.gov (United States)

    Duan, Bin; Dong, Cunhai; Yuan, Xiaoyan; Yao, Kangde

    2004-01-01

    Electrospinning of chitosan solutions with poly(ethylene oxide) (PEO) in an aqueous solution of 2 wt% acetic acid was studied. The properties of the chitosan/PEO solutions, including conductivity, surface tension and viscosity, were measured. Morphology of the electrospun chitosan/PEO was observed by using scanning electron micrographs. Results showed that the ultrafine fibers could be generated after addition of PEO in 2:1 or 1:1 mass ratios of chitosan to PEO from 4-6 wt% chitosan/PEO solutions at 15 kV voltage, 20 cm capillary-collector distance and flow rate 0.1 ml/h. During electrospinning of the chitosan/PEO solutions, ultrafine fibers with diameters from 80 nm to 180 nm were obtained, while microfibers with visually thicker diameters could be formed as well. Results of X-ray photoelectron spectroscopy, Fourier transform infrared spectroscopy and differential scanning calorimeter exhibited the larger electrospun microfibers were almost entirely made from PEO, while the electrospun ultrafine fibers mainly contained chitosan.

  16. Polycation-sodium lauryl ether sulfate-type surfactant complexes: influence of ethylene oxide length.

    Science.gov (United States)

    Vleugels, Leo F W; Pollet, Jennifer; Tuinier, Remco

    2015-05-21

    Polyelectrolyte-surfactant complexes (PESC) are a class of materials which form spontaneously by self-assembly driven by electrostatic and hydrophobic interactions. PESC containing sodium lauryl ether sulfates (SLES) have found wide application in hair care products like shampoo. Typically, SLES with only one or two ethylene oxide (EO) groups are used for this application. We have studied the influence of the size of the EO block (ranging from 0 to 30 EO groups) on complexation with two model polycations: linear polyDADMAC and branched PEI. PESC size and electrostatic properties were determined during stepwise titration of buffered polycation solutions. The critical aggregation concentration (CAC) of PESC was determined by surface tension measurements and fluorescence spectroscopy. For polyDADMAC, there is no influence of the size of the EO block on the complexation behavior; the stiff polycation governs the structure formation. For PEI, it was seen that the EO block size does affect the structure of the complexes. The CAC value of the investigated complexes turns out to be rather independent of the EO block size; however, the CMC/CAC ratio decreases with increasing size of the EO block. This latter observation explains why the Lochhead-Goddard effect is most effective for small EO blocks.

  17. Studies on the properties of poly (ethylene oxide) R-150 hydrogel films formed by irradiation graft

    International Nuclear Information System (INIS)

    Yang Zhanshan; Zhu Nankang; Yang Shuqin; Qiang Yizhong

    1999-01-01

    In order to improve the mechanical properties of poly (ethylene oxide) (PEO) hydrogel film was used as wound dressing. The chemical and physical properties of the PEO R-150 graft hydrogel film formed by blends of electron beam irradiated-PEO R-150 and poly(vinyl alcohol) (PVA) were studied. The experimental results showed that the crosslinking densities of the PEO R-150 graft hydrogel increased along with the increasing of the irradiation doses and decreased with the increasing of the blend concentrations. While the PVA graft proportions did not produce obvious effects on the crosslinking density of the graft hydrogel. The crosslinking density of the graft hydrogel were obviously lower than that of the pure PVA hydrogel. The equilibrium water content of the graft hydrogel decrease as the irradiation dose and the PVA graft proportion increased; but they increased as the blend concentration increased. The equilibrium water content of the graft hydrogel was obviously higher than those of the pure PVA hydrogel. The hardness of the PVA hydrogel film increased with the irradiation dose. The hardness of the graft hydrogel decreased with the blend concentration, whereas it increased with the PVA graft proportion. The results suggest the PVA produces a main effect on the crosslinking density of the graft hydrogel, the PEO R-150 produces a main effect on the equilibrium water content of the graft hydrogel, and the both polymers have double effects on the hardness of the graft hydrogel

  18. The relative safety of gamma-ray, autoclave, and ethylene oxide gas sterilization of thermosetting polyurethane.

    Science.gov (United States)

    Shintani, H

    1995-01-01

    Sterilization of polyurethane (PU) produces 4,4'-methylenedianiline (MDA), a known carcinogen, and various other compounds. The relationships of the components of PU to the formation of these compounds by sterilization were studied. Specimens of PU fabricated from different combinations of isocyanates and polyols were obtained from dialyzers. The molecular weight of the particular polyol was found to influence the production of MDA by sterilization. Sterilization also produced many unidentified compounds. MDA production was not always associated with the production of the other compounds. Compared with gamma-ray irradiation and ethylene oxide gas (EOG) sterilization, autoclave sterilization eluted more hydrophilic compounds. This phenomenon was significant for PUs produced from smaller-molecular-weight polyols. The combination of autoclave sterilization and a PU produced from a larger-molecular-weight polyol is recommended to minimize the production of potentially toxic compounds. Of the techniques studied, EOG sterilization produced the least amounts of MDA and the other compounds, but the residue of EOG is itself problematic. The risk posed by the amounts of MDA extracted was not significant, but the biological safety of the other compounds remains to be determined.

  19. Integrating nitric oxide into salicylic acid and jasmonic acid/ ethylene plant defense pathways.

    Science.gov (United States)

    Mur, Luis A J; Prats, Elena; Pierre, Sandra; Hall, Michael A; Hebelstrup, Kim H

    2013-01-01

    Plant defense against pests and pathogens is known to be conferred by either salicylic acid (SA) or jasmonic acid (JA)/ethylene (ET) pathways, depending on infection or herbivore-grazing strategy. It is well attested that SA and JA/ET pathways are mutually antagonistic allowing defense responses to be tailored to particular biotic stresses. Nitric oxide (NO) has emerged as a major signal influencing resistance mediated by both signaling pathways but no attempt has been made to integrate NO into established SA/JA/ET interactions. NO has been shown to act as an inducer or suppressor of signaling along each pathway. NO will initiate SA biosynthesis and nitrosylate key cysteines on TGA-class transcription factors to aid in the initiation of SA-dependent gene expression. Against this, S-nitrosylation of NONEXPRESSOR OF PATHOGENESIS-RELATED PROTEINS1 (NPR1) will promote the NPR1 oligomerization within the cytoplasm to reduce TGA activation. In JA biosynthesis, NO will initiate the expression of JA biosynthetic enzymes, presumably to over-come any antagonistic effects of SA on JA-mediated transcription. NO will also initiate the expression of ET biosynthetic genes but a suppressive role is also observed in the S-nitrosylation and inhibition of S-adenosylmethionine transferases which provides methyl groups for ET production. Based on these data a model for NO action is proposed but we have also highlighted the need to understand when and how inductive and suppressive steps are used.

  20. Crystallization Behavior of Poly(ethylene oxide) in Vertically Aligned Carbon Nanotube Array.

    Science.gov (United States)

    Sheng, Jiadong; Zhou, Shenglin; Yang, Zhaohui; Zhang, Xiaohua

    2018-03-27

    We investigate the effect of the presence of vertically aligned multiwalled carbon nanotubes (CNTs) on the orientation of poly(ethylene oxide) (PEO) lamellae and PEO crystallinity. The high alignment of carbon nanotubes acting as templates probably governs the orientation of PEO lamellae. This templating effect might result in the lamella planes of PEO crystals oriented along a direction parallel to the long axis of the nanotubes. The presence of aligned carbon nanotubes also gives rise to the decreases in PEO crystallinity, crystallization temperature, and melting temperature due to the perturbation of carbon nanotubes to the crystallization of PEO. These effects have significant implications for controlling the orientation of PEO lamellae and decreasing the crystallinity of PEO and thickness of PEO lamellae, which have significant impacts on ion transport in PEO/CNT composite and the capacitive performance of PEO/CNT composite. Both the decreased PEO crystallinity and the orientation of PEO lamellae along the long axes of vertically aligned CNTs give rise to the decrease in the charge transfer resistance, which is associated with the improvements in the ion transport and capacitive performance of PEO/CNT composite.

  1. Toxic effects of ethylene oxide residues on bovine embryos in vitro.

    Science.gov (United States)

    Holyoak, G R; Wang, S; Liu, Y; Bunch, T D

    1996-04-15

    The potential of ethylene oxide (EtO) residues in exposed plastic tissue culture dishes to adversely affect bovine oocyte maturation, fertilization and subsequent embryonic development was monitored. In experiment 1, the effects of aeration time and aeration combined with washing of EtO-gassed culture dishes on the extent of residual toxicity were investigated. There was no cleavage in any treatment in which oocytes were matured and fertilized in dishes exposed to EtO. EtO residues caused functional degeneration of oocytes even when culture dishes were aerated for more than 12 days post EtO-exposure and repeatedly washed. In experiment 2, the residual toxicity of EtO gas on in vitro maturation (IVM), in vitro fertilization (IVF) and in vitro culture (IVC) were evaluated. Cleavage rate significantly decreased and post-cleavage development was retarded in ova maintained in dishes treated with EtO either during IVM or IVF. EtO residues may be more detrimental to spermatozoa than to oocytes which may have been the primary cause of fertilization failure during IVF.

  2. Toxicity potential of residual ethylene oxide on fresh or frozen embryos maintained in plastic straws.

    Science.gov (United States)

    Schiewe, M C; Schmidt, P M; Pontbriand, D; Wildt, D E

    1988-01-01

    The toxic effects of residual ethylene oxide (EtO), a frequently used gas-sterilant, on embryos either frozen for long-term purposes or stored acutely for 30 min to 9 hr in a fresh condition in 0.25-ml straw containers were evaluated. In Experiment 1, fresh embryos were frozen (using conventional technology) in straws previously aerated for 0 hr to 8 mo after EtO sterilization. With the exception of the 8-mo group in which survival and quality ratings were depressed, embryo viability was not affected significantly by short-term prefreeze and post-thaw exposure to EtO residues. Experiment 2 was conducted to analyze the influence of prefreeze exposure to EtO residues on embryo development in vitro for embryos temporarily stored in previously sterilized straws aerated for different intervals. Compared to non-EtO-sterilized control straws, the development, quality, and viability of embryos exposed to EtO-treated straws were compromised (p less than 0.05) as the aeration interval decreased and the exposure interval increased. The combined results of both experiments indicate that EtO-treated straws can be used to cryopreserve gametes efficiently, but only if the aeration interval is greater than or equal to 72 hr and the prefreeze duration of exposure is less than or equal to 3 hr.

  3. Incipient microphase separation in short chain perfluoropolyether-block-poly(ethylene oxide) copolymers.

    Science.gov (United States)

    Chintapalli, Mahati; Timachova, Ksenia; Olson, Kevin R; Banaszak, Michał; Thelen, Jacob L; Mecham, Sue J; DeSimone, Joseph M; Balsara, Nitash P

    2017-06-07

    Incipient microphase separation is observed by wide angle X-ray scattering (WAXS) in short chain multiblock copolymers consisting of perfluoropolyether (PFPE) and poly(ethylene oxide) (PEO) segments. Two PFPE-PEO block copolymers were studied; one with dihydroxyl end groups and one with dimethyl carbonate end groups. Despite having a low degree of polymerization (N ∼ 10), these materials exhibited significant scattering intensity, due to disordered concentration fluctuations between their PFPE-rich and PEO-rich domains. The disordered scattering intensity was fit to a model based on a multicomponent random phase approximation to determine the value of the interaction parameter, χ, and the radius of gyration, R g . Over the temperature range 30-90 °C, the values of χ were determined to be very large (∼2-2.5), indicating a high degree of immiscibility between the PFPE and PEO blocks. In PFPE-PEO, due to the large electron density contrast between the fluorinated and non-fluorinated block and the high value of χ, disordered scattering was detected at intermediate scattering angles, (q ∼ 2 nm -1 ) for relatively small polymer chains. Our ability to detect concentration fluctuations was enabled by both a relatively large value of χ and significant scattering contrast.

  4. Study of Polydiacetylene-Poly (Ethylene Oxide Electrospun Fibers Used as Biosensors

    Directory of Open Access Journals (Sweden)

    A K M Mashud Alam

    2016-03-01

    Full Text Available Polydiacetylene (PDA is an attractive conjugated material for use in biosensors due to its unique characteristic of undergoing a blue-to-red color change in response to external stimuli. 10,12-Pentacosadiynoic acid (PCDA and poly (ethylene oxide (PEO were used in this study to develop fiber composites via an electrospinning method at various mass ratios of PEO to PCDA, solution concentrations, and injection speeds. The PEO-PDA fibers in blue phase were obtained via photo-polymerization upon UV-light irritation. High mass ratios of PEO to PCDA, low polymer concentrations of spinning solution, and low injection speeds promoted fine fibers with small diameters and smooth surfaces. The colorimetric transition of the fibers was investigated when the fibers were heated at temperatures ranging from 25 °C to 120 °C. A color switch from blue to red in the fibers was observed when the fibers were heated at temperatures greater than 60 °C. The color transition was more sensitive in the fibers made with a low mass ratio of PEO to PCDA due to high fraction of PDA in the fibers. The large diameter fibers also promoted the color switch due to high reflectance area in the fibers. All of the fibers were analyzed using Fourier transform infrared spectroscopy (FT-IR and differential scanning calorimetry (DSC and compared before and after the color change occurred. The colorimetric transitional mechanism is proposed to occur due to conformational changes in the PDA macromolecules.

  5. Stability and effectiveness against bacterial adhesion of poly(ethylene oxide) coatings in biological fluids.

    Science.gov (United States)

    Roosjen, Astrid; de Vries, Joop; van der Mei, Henny C; Norde, Willem; Busscher, Henk J

    2005-05-01

    Poly(ethylene oxide) (PEO) coatings have been shown to reduce the adhesion of different microbial strains and species and thus are promising as coatings to prevent biomaterial-centered infection of medical implants. Clinically, however, PEO coatings are not yet applied, as little is known about their stability and effectiveness in biological fluids. In this study, PEO coatings coupled to a glass substratum through silyl ether bonds were exposed for different time intervals to saliva, urine, or phosphate-buffered saline (PBS) as a reference at 37 degrees C. After exposure, the effectiveness of the coatings against bacterial adhesion was assessed in a parallel plate flow chamber. The coatings appeared effective against Staphylococcus epidermidis adhesion for 24, 48, and 0.5 h in PBS, urine, and saliva, respectively. Using XPS and contact-angle measurements, the variations in effectiveness could be attributed to conditioning film formation. The overall short stability results from hydrolysis of the coupling of the PEO chains to the substratum. (c) 2005 Wiley Periodicals, Inc.

  6. Adhesion mapping of chemically modified and poly(ethylene oxide)-grafted glass surfaces.

    Science.gov (United States)

    Jogikalmath, G; Stuart, J K; Pungor, A; Hlady, V

    1999-08-01

    Two-dimensional mapping of the adhesion pull-off forces was used to study the origin of surface heterogeneity in the grafted poly(ethylene oxide) (PEO) layer. The variance of the pull-off forces measured over the μm-sized regions after each chemical step of modifying glass surfaces was taken to be a measure of the surface chemical heterogeneity. The attachment of γ-glycidoxypropyltrimethoxy silane (GPS) to glass decreased the pull-off forces relative to the clean glass and made the surface more uniform. The subsequent hydrolysis of the terminal epoxide groups resulted in a larger surface heterogeneity which was modeled by two populations of the terminal hydroxyl groups, each with its own distribution of adhesion forces and force variance. The activation of the hydroxyls with carbonyldiimmidazole (CDI) healed the surface and lowered its adhesion, however, the force variance remained rather large. Finally, the grafting of the α,ω-diamino poly(ethyleneoxide) chains to the CDI-activated glass largely eliminated adhesion except at a few discrete regions. The adhesion on the PEO grafted layer followed the Poisson distribution of the pull-off forces. With the exception of the glass surface, a correlation between the water contact angles and the mean pull-off forces measured with the Si(3)N(4) tip surfaces was found for all modified glass surfaces.

  7. Self-assembly of Polystyrene- b -poly(2-vinylpyridine)- b -poly(ethylene oxide) Triblock Terpolymers

    KAUST Repository

    Musteata, Valentina-Elena; Sutisna, Burhannudin; Polymeropoulos, Georgios; Avgeropoulos, Apostolos; Meneau, Florian; Peinemann, Klaus-Viktor; Hadjichristidis, Nikolaos; Nunes, Suzana Pereira

    2017-01-01

    Polystyrene-b-poly(2-vinylpyridine)-b-poly(ethylene oxide) (PS-b-P2VP-b-PEO) terpolymer is a versatile polymer to form isoporous films and membranes, due to the possibility of self-assembly control and the properties of the different blocks, such as the P2VP ability of complexation, and H-bond formation, and the PEO biocompatibility. Copolymers with different block ratios and sizes were synthesized. The correlation between their equilibrium bulk morphology, the self-assembly in dilute and semi-dilute solutions and the non-equilibrium porous structures of membranes, obtained by non-solvent induced phase separation, was investigated and discussed in detail. The characterization was performed by small-angle X-ray scattering (SAXS), scanning (SEM) and transmission electron microscopy (TEM). Hexagonal, cubic and lamellar arrangements were observed. The preparation conditions were optimized and a regular, isoporous morphology, suitable for membrane application, was successfully obtained with PS80.5k-b-P2VP64.4k-b-PEO16.1k.

  8. Carbonate-linked poly(ethylene oxide) polymer electrolytes towards high performance solid state lithium batteries

    International Nuclear Information System (INIS)

    He, Weisheng; Cui, Zili; Liu, Xiaochen; Cui, Yanyan; Chai, Jingchao; Zhou, Xinhong; Liu, Zhihong; Cui, Guanglei

    2017-01-01

    The classic poly(ethylene oxide) (PEO) based solid polymer electrolyte suffers from poor ionic conductivity of ambient temperature, low lithium ion transference number and relatively narrow electrochemical window (<4.0 V vs. Li + /Li). Herein, the carbonate-linked PEO solid polymer such as poly(diethylene glycol carbonate) (PDEC) and poly(triethylene glycol carbonate) (PTEC) were explored to find out the feasibility of resolving above issues. It was proven that the optimized ionic conductivity of PTEC based electrolyte reached up to 1.12 × 10 −5 S cm −1 at 25 °C with a decent lithium ion transference number of 0.39 and a wide electrochemical window about 4.5 V vs. Li + /Li. In addition, the PTEC based Li/LiFePO 4 cell could be reversibly charged and discharged at 0.05 C-rates at ambient temperature. Moreover, the higher voltage Li/LiFe 0.2 Mn 0.8 PO 4 cell (cutoff voltage 4.35 V) possessed considerable rate capability and excellent cycling performance even at ambient temperature. Therefore, these carbonate-linked PEO electrolytes were demonstrated to be fascinating candidates for the next generation solid state lithium batteries simultaneously with high energy and high safety.

  9. Phase Separation and Elastic Properties of Poly(Trimethylene Terephthalate-block-poly(Ethylene Oxide Copolymers

    Directory of Open Access Journals (Sweden)

    Elżbieta Piesowicz

    2016-06-01

    Full Text Available A series of poly(trimethylene terephthalate-block-poly(ethylene oxide (PTT-b-PEOT copolymers with different compositions of rigid PTT and flexible PEOT segments were synthesized via condensation in the melt. The influence of the block length and the block ratio on the micro-separated phase structure and elastic properties of the synthesized multiblock copolymers was studied. The PEOT segments in these copolymers were kept constant at 1130, 2130 or 3130 g/mol, whereas the PTT content varied from 30 up to 50 wt %. The phase separation was assessed using differential scanning calorimetry (DSC and dynamic mechanical thermal analysis (DMTA. The crystal structure of the synthesised block copolymers and their microstructure on the manometer scale was evaluated by using WAXS and SAXS analysis. Depending on the PTT/PEOT ratio, but also on the rigid and flexible segment length in PTT-b-PEO copolymers, four different domains were observed i.e.,: a crystalline PTT phase, a crystalline PEO phase (which exists for the whole series based on three types of PEOT segments, an amorphous PTT phase (only at 50 wt % content of PTT rigid segments and an amorphous PEO phase. Moreover, the elastic deformability and reversibility of PTT-b-PEOT block copolymers were studied during a cyclic tensile test. Determined values of permanent set resultant from maximum attained stain (100% and 200% for copolymers were used to evaluate their elastic properties.

  10. Self-assembly of Polystyrene- b -poly(2-vinylpyridine)- b -poly(ethylene oxide) Triblock Terpolymers

    KAUST Repository

    Musteata, Valentina-Elena

    2017-11-08

    Polystyrene-b-poly(2-vinylpyridine)-b-poly(ethylene oxide) (PS-b-P2VP-b-PEO) terpolymer is a versatile polymer to form isoporous films and membranes, due to the possibility of self-assembly control and the properties of the different blocks, such as the P2VP ability of complexation, and H-bond formation, and the PEO biocompatibility. Copolymers with different block ratios and sizes were synthesized. The correlation between their equilibrium bulk morphology, the self-assembly in dilute and semi-dilute solutions and the non-equilibrium porous structures of membranes, obtained by non-solvent induced phase separation, was investigated and discussed in detail. The characterization was performed by small-angle X-ray scattering (SAXS), scanning (SEM) and transmission electron microscopy (TEM). Hexagonal, cubic and lamellar arrangements were observed. The preparation conditions were optimized and a regular, isoporous morphology, suitable for membrane application, was successfully obtained with PS80.5k-b-P2VP64.4k-b-PEO16.1k.

  11. Electrode-Impregnable and Cross-Linkable Poly(ethylene oxide)-Poly(propylene oxide)-Poly(ethylene oxide) Triblock Polymer Electrolytes with High Ionic Conductivity and a Large Voltage Window for Flexible Solid-State Supercapacitors.

    Science.gov (United States)

    Han, Jae Hee; Lee, Jang Yong; Suh, Dong Hack; Hong, Young Taik; Kim, Tae-Ho

    2017-10-04

    We present cross-linkable precursor-type gel polymer electrolytes (GPEs) that have large ionic liquid uptake capability, can easily penetrate electrodes, have high ion conductivity, and are mechanically strong as high-performance, flexible all-solid-state supercapacitors (SC). Our polymer precursors feature a hydrophilic-hydrophobic poly(ethylene oxide)-poly(propylene oxide)-poly(ethylene oxide) (PEO-PPO-PEO) triblock main-chain structure and trifunctional silane end groups that can be multi-cross-linked with each other through a sol-gel process. The cross-linked solid-state electrolyte film with moderate IL content (200 wt %) shows a well-balanced combination of excellent ionic conductivity (5.0 × 10 -3 S cm -1 ) and good mechanical stability (maximum strain = 194%). Moreover, our polymer electrolytes have various advantages including high thermal stability (decomposition temperature > 330 °C) and the capability to impregnate electrodes to form an excellent electrode-electrolyte interface due to the very low viscosity of the precursors. By assembling our GPE-impregnated electrodes and solid-state GPE film, we demonstrate an all-solid-state SC that can operate at 3 V and provides an improved specific capacitance (112.3 F g -1 at 0.1 A g -1 ), better rate capability (64% capacity retention until 20 A g -1 ), and excellent cycle stability (95% capacitance decay over 10 000 charge/discharge cycles) compared with those of a reference SC using a conventional PEO electrolyte. Finally, flexible SCs with a high energy density (22.6 W h kg -1 at 1 A g -1 ) and an excellent flexibility (>93% capacitance retention after 5000 bending cycles) can successfully be obtained.

  12. Effect of block composition on thermal properties and melt viscosity of poly[2-(dimethylaminoethyl methacrylate], poly(ethylene oxide and poly(propylene oxide block co-polymers

    Directory of Open Access Journals (Sweden)

    2011-09-01

    Full Text Available To modify the rheological properties of certain commercial polymers, a set of block copolymers were synthesized through oxyanionic polymerization of 2-(dimethylaminoethyl methacrylate to the chain ends of commercial prepolymers, namely poly(ethylene oxide (PEO, poly(ethylene oxide-block-poly(propylene oxide-block-poly(ethylene oxide (PEO-PPO-PEO, and poly(propylene oxide (PPO. The formed block copolymers were analysed with size exclusion chromatography and nuclear magnetic resonance spectroscopy in order to confirm block formation. Thermal characterization of the resulting polymers was done with differential scanning calorimetry. Thermal transition points were also confirmed with rotational rheometry, which was primarily used to measure melt strength properties of the resulting block co-polymers. It was observed that the synthesised poly[2-(dimethylaminoethyl methacrylate]-block (PDM affected slightly the thermal transition points of crystalline PEO-block but the influence was stronger on amorphous PPO-blocks. Frequency sweeps measured above the melting temperatures for the materials confirmed that the pre-polymers (PEO and PEO-PPO-PEO behave as Newtonian fluids whereas polymers with a PDM block structure exhibit clear shear thinning behaviour. In addition, the PDM block increased the melt viscosity when compared with that one of the pre-polymer. As a final result, it became obvious that pre-polymers modified with PDM were in entangled form, in the melted state as well in the solidified form.

  13. Study on Optoelectronic Characteristics of Sn-Doped ZnO Thin Films on Poly(ethylene terephthalate) and Indium Tin Oxide/Poly(ethylene terephthalate) Flexible Substrates

    Science.gov (United States)

    Cheng, Chi-Hwa; Chen, Mi; Chiou, Chin-Lung; Liu, Xing-Yang; Weng, Lin-Song; Koo, Horng-Show

    2013-05-01

    Transparent conductive oxides of Sn-doped ZnO (SZO) films with doping weight ratios of 2.0, 3.0, 4.0, and 5.0 wt % have been deposited on indium tin oxide (ITO)/poly(ethylene terephthalate) (PET) and PET flexible substrates at room temperature by pulsed laser deposition (PLD). Resultant films of SZO on ITO/PET and PET flexible substrates are amorphous in phase. It is found that undoped and SZO films on ITO/PET is anomalously better than films on PET in optical transmittance in the range of longer wavelength, possibly due to the refraction index difference between SZO, ITO films, and PET substrates, Burstein-Moss effect and optical interference of SZO/ITO bilayer films and substrate materials, and furthermore resulting in the decrement of reflection. The lowest electrical resistivity (ρ) of 4.0 wt % SZO films on flexible substrates of PET and ITO/PET are 3.8×10-2 and ρ= 1.2×10-2 Ω.cm, respectively. It is found that electrical and optical properties of the resultant films are greatly dependent on various amount of Sn element doping effect and substrate material characteristics.

  14. Highly active and non-corrosive catalytic systems for the coupling reactions of ethylene oxide and CO{sub 2}

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Shuyao; Jin, So Jeong; Kim, Young Jin; Lee, Je Seung; Kim, Hoon Sik [Dept. of Chemistry and Research Institute of Basic Sciences, Kyung Hee University, Seoul (Korea, Republic of); Hong, Jongki; Lee, Won Woong [College of Pharmacy, Kyung Hee University, Seoul (Korea, Republic of); Ryu, Jung Bok [R and D Center, Chuncheon (Korea, Republic of)

    2017-02-15

    Lithium halide-based molten salts (LiX-[BMIm]Br) synthesized from the reactions of lithium halides (LiX, X = Cl or Br) with 1-butyl-3-methylimidazolium bromide ([BMIm]Br), and their catalytic performances and corrosivities were tested for the coupling reactions of ethylene oxide with carbon dioxide to produce ethylene carbonate. The activity of a molten salt was influenced with the change of halide ion. At a fixed molar amount of LiX, the activity of LiX-[BMIm]Br increased with increasing molar ratio of LiX/[BMIm]Br up to 1–1.25, and then decreased thereafter. Fast atom bombardment mass spectral analysis of LiBr-[BMIm]Br, obtained by dissolving LiBr in [BMIm]Br in a 1:1 molar ratio, implies that [Li{sub a} X{sub a+1}]{sup −} are active species for the carboxylation of ethylene oxide with LiX-[BMIm]Br. The corrosion test toward carbon steel coupons demonstrates that all the Cl-containing molten salts are corrosive, whereas the salts without containing Cl{sup −} are non-corrosive under the carboxylation condition.

  15. Interactions between nitric oxide and ethylene in monomeric G-protein activation in relation to food spoilage

    DEFF Research Database (Denmark)

    Hall, M A; moshkov, moshkov; Novikova, G

    2014-01-01

    Climate change is likely to increase crop stress with negative impacts on yield and quality. Therefore, there is a need to develop our understanding of the key events which govern plant tolerance to stress. Intense research has identified key signalling cascades regulating stress tolerance...... and it is notable that many are dependent on the production of volatile signals or signals which have volatile derivatives. Ethylene (ET) has long been recognized as an important regulator of development, stress responses, senescence and food spoilage. Our work has focused on the gaseous signal nitric oxide (NO......) and how it interacts with established stress signalling pathways and in particular, those regulated by ET. Using laser photoacoustic detection (LPAD) we have established that NO production overlaps with that of ethylene during plant responses to disease. To examine the interaction of NO and ET signalling...

  16. A physiologically based pharmacokinetic model for ethylene oxide in mouse, rat, and human.

    Science.gov (United States)

    Fennell, T R; Brown, C D

    2001-06-15

    Ethylene oxide (EO) is widely used as a gaseous sterilant and industrial intermediate and is a direct-acting mutagen and carcinogen. The objective of these studies was to develop physiologically based pharmacokinetic (PB-PK) models for EO to describe the exposure-tissue dose relationship in rodents and humans. We previously reported results describing in vitro and in vivo kinetics of EO metabolism in male and female F344 rats and B6C3F1 mice. These studies were extended by determining the kinetics of EO metabolism in human liver cytosol and microsomes. The results indicate enzymatically catalyzed GSH conjugation via cytosolic glutathione S-transferase (cGST) and hydrolysis via microsomal epoxide hydrolase (mEH) occur in both rodents and humans. The in vitro kinetic constants were scaled to account for cytosolic (cGST) and microsomal (mEH) protein content and incorporated into PB-PK descriptions for mouse, rat, and human. Flow-limited models adequately predicted blood and tissue EO levels, disposition, and elimination kinetics determined experimentally in rats and mice, with the exception of testis concentrations, which were overestimated. Incorporation of a diffusion-limited description for testis improved the ability of the model to describe testis concentrations. The model accounted for nonlinear increases in blood and tissue concentrations that occur in mice on exposure to EO concentrations greater than 200 ppm. Species differences are predicted in the metabolism and exposure-dose relationship, with a nonlinear relationship observed in the mouse as a result of GSH depletion. These models represent an essential step in developing a mechanistically based EO exposure-dose-response description for estimating human risk from exposure to EO. Copyright 2001 Academic Press.

  17. Occupational exposure to ethylene oxide--OSHA. Final rule: supplemental statement of reasons.

    Science.gov (United States)

    1985-01-02

    On June 22, 1984, the Occupational Safety and Health Administration (OSHA) published a final standard for ethylene oxide (EtO) that established a permissible exposure limit of 1 part EtO per million parts of air determined as an 8-hour time--weighted average (TWA) concentration (29 CFR 1910.1047, 49 FR 25734). The standard also includes provisions for methods of exposure control, personal protective equipment, measurement of employee exposure, training, signs, and labels, medical surveillance, regulated areas, emergencies and recordkeeping. The basis for this action was a determination by OSHA, based on human and animal data, that exposure to EtO presents a carcinogenic, mutagenic, genotoxic, reproductive, neurologic, and sensitization hazard to workers. During the rulemaking proceedings that led to the establishment of the 1 ppm TWA, the issue of whether there was a need for a short-term exposure limit (STEL) for workers protection from EtO was raised. OSHA reserved decision on the adoption of a STEL at the conclusion of the rulemaking in order to permit peer review of the available evidence and to review more fully the arguments and pertinent data regarding the STEL issue. Upon receipt of the analyses from most of the peer reviewers, OSHA published a notice to that effect on September 19, 1984 (49 FR 36659) and invited public comment on the pertinent issues addressed in the peer reviews. Based on the entire rulemaking record, including the peer reviews and public comments received since June 22, the Assistant Secretary has determined that adoption of a STEL for EtO is not warranted by the available health evidence, and that a STEL is not reasonably necessary or appropriate for inclusion in the final EtO standard. OSHA has also asked that NIOSH fund certain additional studies related to whether a dose-rate relationship can be established for EtO, and OSHA will review the results of those studies when they become available.

  18. Impact of ethylene oxide gas sterilization of duodenoscopes after a carbapenem-resistant Enterobacteriaceae outbreak.

    Science.gov (United States)

    Naryzhny, Igor; Silas, Dean; Chi, Kenneth

    2016-08-01

    Carbapenem-resistant Enterobacteriaceae (CRE) outbreaks have been implicated at several medical institutions involving gastroenterology laboratories and, specifically, duodenoscopes. Currently, there are no specific guidelines to eradicate or prevent the outbreak of this bacteria. We describe ethylene oxide (ETO) gas sterilizations of duodenoscopes to address this issue. A complete investigation of the gastroenterology laboratory and an evaluation by the Centers for Disease Control and Prevention concluded that no lapses were found in the reprocessing of the equipment. With no deficiencies to address, we began a novel cleaning process using surgical ETO gas sterilizers in addition to standard endoscope reprocessing recommendations and guidelines, all while trying to eradicate the CRE contamination and prevent future recurrences. We also instituted a surveillance system for recurrence of CRE contamination via monthly cultures of the duodenoscopes. Between October 2013 and April 2014, 589 ERCPs were performed with 645 ETO gas sterilizations of 6 duodenoscopes. Given the extra 16 hours needed to sterilize the duodenoscopes, our institution incurred costs resulting from purchasing additional equipment and surveillance cultures. Four duodenoscopes sustained damage during this period; however, this could not be directly attributed to the sterilization process. Furthermore, after an 18-month success period we encountered a positive CRE culture after sterilization, albeit of a different strain than originally detected during the outbreak. The duodenoscope underwent additional ETO gas sterilization, with a negative repeated culture; all potentially exposed individuals screened negative for CRE. Proper use of high-level disinfection alone may not eliminate multidrug-resistant organisms from duodenoscopes. In this single-center study, the addition of ETO sterilization and frequent monitoring with cultures reduced duodenoscope contamination and eliminated clinical infections

  19. Dose-rate effects of ethylene oxide exposure on developmental toxicity.

    Science.gov (United States)

    Weller, E; Long, N; Smith, A; Williams, P; Ravi, S; Gill, J; Henessey, R; Skornik, W; Brain, J; Kimmel, C; Kimmel, G; Holmes, L; Ryan, L

    1999-08-01

    In risk assessment, evaluating a health effect at a duration of exposure that is untested involves assuming that equivalent multiples of concentration (C) and duration (T) of exposure have the same effect. The limitations of this approach (attributed to F. Haber, Zur Geschichte des Gaskrieges [On the history of gas warfare], in Funf Vortrage aus den Jahren 1920-1923 [Five lectures from the years 1920-1923], 1924, Springer, Berlin, pp. 76-92), have been noted in several studies. The study presented in this paper was designed to specifically look at dose-rate (C x T) effects, and it forms an ideal case study to implement statistical models and to examine the statistical issues in risk assessment. Pregnant female C57BL/6J mice were exposed, on gestational day 7, to ethylene oxide (EtO) via inhalation for 1.5, 3, or 6 h at exposures that result in C x T multiples of 2100 or 2700 ppm-h. EtO was selected because of its short half-life, documented developmental toxicity, and relevance to exposures that occur in occupational settings. Concurrent experiments were run with animals exposed to air for similar periods. Statistical analysis using models developed to assess dose-rate effects revealed significant effects with respect to fetal death and resorptions, malformations, crown-to-rump length, and fetal weight. Animals exposed to short, high exposures of EtO on day 7 of gestation were found to have more adverse effects than animals exposed to the same C x T multiple but at longer, lower exposures. The implication for risk assessment is that applying Haber's Law could potentially lead to an underestimation of risk at a shorter duration of exposure and an overestimation of risk at a longer duration of exposure. Further research, toxicological and statistical, are required to understand the mechanism of the dose-rate effects, and how to incorporate the mechanistic information into the risk assessment decision process.

  20. Ionic conductivity in polyethylene-b-poly(ethylene oxide)/lithium perchlorate solid polymer electrolytes

    International Nuclear Information System (INIS)

    Guilherme, L.A.; Borges, R.S.; Moraes, E. Mara S.; Silva, G. Goulart; Pimenta, M.A.; Marletta, A.; Silva, R.A.

    2007-01-01

    The ionic conductivity and phase arrangement of solid polymeric electrolytes based on the block copolymer polyethylene-b-poly(ethylene oxide) (PE-b-PEO) and LiClO 4 have been investigated. One set of electrolytes was prepared from copolymers with 75% of PEO units and another set was based on a blend of copolymer with 50% PEO units and homopolymers. The differential scanning calorimetry (DSC) results, for electrolytes based on the copolymer with 75% of PEO units, were dominated by the PEO phase. The PEO block crystallinity dropped and the glass transition increased with salt addition due to the coordination of the cation by PEO oxygen. The conductivity for copolymers 75% PEO-based electrolyte with 15 wt% of salt was higher than 10 -5 S/cm at room temperature and reached to 10 -3 S/cm at 100 deg. C on a heating measurement. The blend of PE-b-PEO (50% PEO)/PEO/PE showed a complex thermal behavior with decoupled melting of the blocks and the homopolymers. Upon salt addition the endotherms associated with PEO domains disappeared and the PE crystals remained untouched. The conductivity results were limited at 100 deg. C to values close to 10 -4 S/cm and at room temperature values close to 3 x 10 -6 S/cm were obtained for the 15 wt% salt electrolyte. Raman study showed that the ionic association of the highly concentrated blend electrolytes at room temperature is not significant. Therefore, the lower values of conductivity in the case of the blend with 50% PEO can be assigned to the higher content of PE domains leading to a morphology with lower connectivity for ionic conduction both in the crystalline and melted state of the PE domains

  1. Dynamics in coarse-grained models for oligomer-grafted silica nanoparticles

    KAUST Repository

    Hong, Bingbing

    2012-01-01

    Coarse-grained models of poly(ethylene oxide) oligomer-grafted nanoparticles are established by matching their structural distribution functions to atomistic simulation data. Coarse-grained force fields for bulk oligomer chains show excellent transferability with respect to chain lengths and temperature, but structure and dynamics of grafted nanoparticle systems exhibit a strong dependence on the core-core interactions. This leads to poor transferability of the core potential to conditions different from the state point at which the potential was optimized. Remarkably, coarse graining of grafted nanoparticles can either accelerate or slowdown the core motions, depending on the length of the grafted chains. This stands in sharp contrast to linear polymer systems, for which coarse graining always accelerates the dynamics. Diffusivity data suggest that the grafting topology is one cause of slower motions of the cores for short-chain oligomer-grafted nanoparticles; an estimation based on transition-state theory shows the coarse-grained core-core potential also has a slowing-down effect on the nanoparticle organic hybrid materials motions; both effects diminish as grafted chains become longer. © 2012 American Institute of Physics.

  2. The effect of moderate alcohol consumption on adiponectin oligomers and muscle oxidative capacity: A human intervention study

    NARCIS (Netherlands)

    Beulens, J.W.J.; Loon, L.J.C. van; Kok, F.J.; Pelsers, M.; Bobbert, T.; Spranger, J.; Helander, A.; Hendriks, H.F.J.

    2007-01-01

    Aims/hypothesis: The aim of this study was to investigate whether moderate alcohol consumption increases plasma high molecular weight (HMW) adiponectin and/or muscle oxidative capacity. Materials and methods: Eleven lean (BMI 18-25 kg/m2) and eight overweight (BMI ≥27 kg/m2) men consumed 100 ml

  3. Effects of γ- and x-irradiation upon activity and selectivity of a supported silver catalyst in the oxidation of ethylene and carbon monoxide

    International Nuclear Information System (INIS)

    Mora Vallejo, R.J.

    1975-01-01

    Effects of γ and x-radiation on catalytic selectivity of supported silver catalysts for production of ethylene oxide via ethylene oxidation were compared by determination of radio-induced changes in conversion-yield profiles. Influence of photon energy on the kinetics of the irradiation process was studied by determination of conversion-yield profiles, using samples of catalyst exposed to x-rays of different mean photon energy and γ-rays for different cumulative periods of time. The effect of γ-radiation on catalytic activity of the same silver catalysts for carbon monoxide oxidation was analyzed by determination of the reaction kinetics before and after catalyst irradiation

  4. Theoretical consideration on phase behaviors of poly(ethylene oxide-block-propylene oxide)/LiCF3SO3 systems in lithium battery

    International Nuclear Information System (INIS)

    Ko, Sung Jin; Kim, Sun Joon; Kong, Sung Ho; Bae, Young Chan

    2004-01-01

    A new thermodynamic model is developed based on the extended perturbed hard sphere chain (PHSC) model and melting point depression theory to describe the phase behaviors of copolymer electrolyte/salt systems. The phase behaviors of poly(ethylene oxide-block-propylene oxide)/LiCF 3 SO 3 systems are investigated by thermo-optical analysis (TOA) technique. Quantitative descriptions according to the proposed model are in good agreement with experimental data. The obtained results show that monomer ratio and sequence type of copolymers play a great role in determining eutectic points of the given systems

  5. Highly open bowl-like PtAuAg nanocages as robust electrocatalysts towards ethylene glycol oxidation

    Science.gov (United States)

    Xu, Hui; Yan, Bo; Li, Shumin; Wang, Jin; Song, Pingping; Wang, Caiqin; Guo, Jun; Du, Yukou

    2018-04-01

    A novel combined seed mediated and galvanic replacement method has been demonstrated to synthesize a new class of trimetallic PtAuAg nanocatalysts with highly open bowl-like nanocage structure. The newly-generated PtAuAg nanocages catalysts exhibit superior electrocatalytic performances towards ethylene glycol oxidation with the mass activity of 6357.1 mA mg-1, 5.5 times higher than that of commercial Pt/C (1151.1 mA mg-1). This work demonstrates the first example of designing shape-controlled architectures of trimetallic bowl-like PtAuAg nanocages for liquid fuel electrooxidation.

  6. Membrane protein resistance of oligo(ethylene oxide) self-assembled monolayers.

    Science.gov (United States)

    Vaish, Amit; Vanderah, David J; Vierling, Ryan; Crawshaw, Fay; Gallagher, D Travis; Walker, Marlon L

    2014-10-01

    As part of an effort to develop biointerfaces for structure-function studies of integral membrane proteins (IMPs) a series of oligo(ethylene oxide) self-assembled monolayers (OEO-SAMs) were evaluated for their resistance to protein adsorption (RPA) of IMPs on Au and Pt. Spectroscopic ellipsometry (SE) was used to determine SAM thicknesses and compare the RPA of HS(CH2)3O(CH2CH2O)6CH3 (1), HS(CH2)3O(CH2CH2O)6H (2), [HS(CH2)3]2CHO(CH2CH2O)6CH3 (3) and [HS(CH2)3]2CHO(CH2CH2O)6H (4), assembled from water. For both substrates, SAM thicknesses for 1 to 4 were found to be comparable indicating SAMs with similar surface coverages and OEO chain order and packing densities. Fibrinogen (Fb), a soluble plasma protein, and rhodopsin (Rd), an integral membrane G-protein coupled receptor, adsorbed to the SAMs of 1, as expected from previous reports, but not to the hydroxy-terminated SAMs of 2 and 4. The methoxy-terminated SAMs of 3 were resistant to Fb but, surprisingly, not to Rd. The stark difference between the adsorption of Rd to the SAMs of 3 and 4 clearly indicate that a hydroxy-terminus of the OEO chain is essential for high RPA of IMPs. The similar thicknesses and high RPA of the SAMs of 2 and 4 show the conditions of protein resistance (screening the underlying substrate, packing densities, SAM order, and conformational mobility of the OEO chains) defined from previous studies on Au are applicable to Pt. In addition, the SAMs of 4, exhibiting the highest resistance to Fb and Rd, were placed in contact with undiluted fetal bovine serum for 2h. Low protein adsorption (≈12.4ng/cm(2)), obtained under these more challenging conditions, denote a high potential of the SAMs of 4 for various applications requiring the suppression of non-specific protein adsorption. Published by Elsevier B.V.

  7. One-pot synthesis of star-shaped macromolecules containing polyglycidol and poly(ethylene oxide) arms.

    Science.gov (United States)

    Lapienis, Grzegorz; Penczek, Stanislaw

    2005-01-01

    Synthesis of fully hydrophilic star-shaped macromolecules with different kinds of arms (A(x)B(y)C(z)) based on polyglycidol (PGL, A(x)) and poly(ethylene oxide) (PEO, C(z)) arms and diepoxy compounds (diglycidyl ethers of ethylene glycol (DGEG) or neopentyl glycol (DGNG) in the core, B(y)) forming the core is described. Precursors of arms were prepared by polymerization of glycidol with protected -OH groups. The first-generation stars were formed in the series of consecutive-parallel reactions of arms A(x) with diepoxy compounds (B). These first-generation stars (A(x)B(y)), having approximately O-, Mt+ groups on the cores, were used as multianionic initiators for the second generation of arms (C(z)) built by polymerization of ethylene oxide. The products with M(n) up to 10(5) and having up to approximately 40 arms were obtained. The number of arms (f) was determined by direct measurements of M(n) of the first-generation stars (M(n) of arms A(x) is known), compared with f calculated from the branching index g, determined from R(g) measured with size-exclusion chromatography (SEC) triple detection with TriSEC software. The progress of the star formation was monitored by 1H NMR and SEC. These novel water-soluble stars, having a large number of hydroxyl groups, both at the ends of PEO arms as well as within the PGL arms, can be functionalized and further used for attaching compounds of interest. This approach opens, therefore, a new way of "multiPEGylation".

  8. Surface morphology and dewettability of self-organized thermosets involving epoxy and POSS-capped poly(ethylene oxide) telechelics

    International Nuclear Information System (INIS)

    Wang, Lei; Zheng, Sixun

    2012-01-01

    A heptaphenyl polyhedral oligomeric silsesquioxane-capped poly(ethylene oxide) (POSS-capped PEO) telechelics was synthesized via the Huisgen 1,3-dipolar cycloaddition between 3-azidopropylheptaphenyl POSS and α,ω-dialkynyl-terminated poly(ethylene oxide). The organic–inorganic amphiphile was incorporated into epoxy to obtain the organic–inorganic nanocomposites. The morphology of the nanocomposites was investigated by means of atomic force microscopy (AFM) and dynamic mechanical thermal analysis (DMTA). It was found that the epoxy thermosets containing POSS-capped PEO telechelics were microphase-separated. The formation of the nanophases in the thermosets followed a self-assembly mechanism. The static contact angle measurements show that the nanocomposites displayed a significant enhancement in surface hydrophobicity as well as reduction in surface free energy. The improvement in surface dewettability was ascribed to the enrichment of POSS cages at the surface of the nanocomposites and the formation of the specific surface morphology as evidenced by X-ray photoelectron spectroscopy (XPS) and surface atomic force microscopy (AFM). -- Highlights: ► POSS-capped PEO telechelics was synthesized via click chemistry approach. ► The organic–inorganic amphiphile can be self-assembled into the nanophases in epoxy. ► The hybrid nanocomposites were successfully prepared via a self-assembly approach. ► The nanocomposites displayed a significant enhancement in surface hydrophobicity.

  9. Comblike poly(ethylene oxide)/hydrophobic C6 branched chitosan surfactant polymers as anti-infection surface modifying agents.

    Science.gov (United States)

    Mai-ngam, Katanchalee

    2006-05-01

    A series of structurally well-defined poly(ethylene oxide)/hydrophobic C6 branched chitosan surfactant polymers that undergo surface induced self assembly on hydrophobic biomaterial surfaces were synthesized and characterized. The surfactant polymers consist of low molecular weight (Mw) chitosan backbone with hydrophilic poly(ethylene oxide) (PEO) and hydrophobic hexyl pendant groups. Chitosan was depolymerized by nitrous acid deaminative cleavage. Hexanal and aldehyde-terminated PEO chains were simultaneously attached to low Mw chitosan hydrochloride via reductive amination. The surfactant polymers were prepared with various ratios of the two side chains. The molecular composition of the surfactant polymers was determined by FT-IR and 1H NMR. Surface active properties at the air-water interface were determined by Langmuir film balance measurements. The surfactant polymers with PEO/hexyl ratios of 1:3.0 and 1:14.4 were used as surface modifying agents to investigate their anti-infection properties. E. coli adhesion on Silastic surface was decreased significantly by the surfactant polymer with PEO/hexyl 1:3.0. Surface growth of adherent E. coli was effectively suppressed by both tested surfactant polymers.

  10. Highly Controlled Diffusion Drug Release from Ureasil-Poly(ethylene oxide)-Na+-Montmorillonite Hybrid Hydrogel Nanocomposites.

    Science.gov (United States)

    Jesus, Celso R N; Molina, Eduardo F; Pulcinelli, Sandra H; Santilli, Celso V

    2018-06-06

    In this work, we report the effects of incorporation of variable amounts (1-20 wt %) of sodium montmorillonite (MMT) into a siloxane-poly(ethylene oxide) hybrid hydrogel prepared by the sol-gel route. The aim was to control the nanostructural features of the nanocomposite, improve the release profile of the sodium diclofenac (SDCF) drug, and optimize the swelling behavior of the hydrophilic matrix. The nanoscopic characteristics of the siloxane-cross-linked poly(ethylene oxide) network, the semicrystallinity of the hybrid, and the intercalated or exfoliated structure of the clay were investigated by X-ray diffraction, small-angle X-ray scattering, and differential scanning calorimetry. The correlation between the nanoscopic features of nanocomposites containing different amounts of MMT and the swelling behavior revealed the key role of exfoliated silicate in controlling the water uptake by means of a flow barrier effect. The release of the drug from the nanocomposite displayed a stepped pattern kinetically controlled by the diffusion of SDCF molecules through the mass transport barrier created by the exfoliated silicate. The sustained SDCF release provided by the hybrid hydrogel nanocomposite could be useful for the prolonged treatment of painful conditions, such as arthritis, sprains and strains, gout, migraine, and pain after surgical procedures.

  11. Characteristics of tau oligomers

    Directory of Open Access Journals (Sweden)

    Yan eRen

    2013-07-01

    Full Text Available In Alzheimer disease (AD and other tauopathies, microtubule-associated protein tau becomes hyperphosphorylated, undergoes conformational changes, aggregates, eventually becoming neurofibrillary tangles (NFTs. As accumulating evidence suggests that NFTs themselves may not be toxic, attention is now turning toward the role of intermediate tau oligomers in AD pathophysiology. Sarkosyl extraction is a standard protocol for investigating insoluble tau aggregates in brains. There is a growing consensus that sarkosyl-insoluble tau correlates with the pathological features of tauopathy. While sarkosyl-insoluble tau from tauopathy brains has been well characterized as a pool of filamentous tau, other dimers, multimers, and granules of tau are much less well understood. There are protocols for identifying these tau oligomers. In this mini review, we discuss the characteristics of tau oligomers isolated via different methods and materials.

  12. EFFECTS OF ω-ACRYLOYL POLY(ETHYLENE OXIDE) MACROMONOMER ON EMULSIFIER-FREE EMULSION COPOLYMERIZATION OF METHYL METHACRYLATE AND n-BUTYL ACRYLATE

    Institute of Scientific and Technical Information of China (English)

    1998-01-01

    Well-defined nonionic hydrophilic ω-acryloyl poly(ethylene oxide) macromonomer (PEO-A) has been prepared by living anionic polymerization of ethylene oxide with diphenyl methyl potassium as the initiator and acryloyl chloride as the reaction terminating agent. The polymer was characterized by FTIR and SEC. The emulsifier-free emulsion polymerization of methyl methacrylate (MMA) and n-butyl acrylate (BA) containing various concentrations of PEO-A was studied. In all cases stable emulsion coplymerizations of MMA and BA were obtained. The stabilizing effect was found to be dependent on the molecular weight and the feed amount of the macromonomer.

  13. [Carcinogenic activity of ethylene oxide and its reaction products 2-chloroethanol, 2-bromoethanol, ethylene glycol and diethylene glycol. III. Research on ethylene glycol and diethylene glycol for carcinogenic effects].

    Science.gov (United States)

    Dunkelberg, H

    1987-03-01

    Ethylene glycol and diethylene glycol were each administered once weekly subcutaneously to groups of 100 female NMRI mice at 3 dosages (30; 10 und 3 mg single dose per mouse). Tricaprylin was used as solvent. The mean total dosage per mouse was 2110.5; 707.0 and 196.2 mg for ethylene glycol and 2029.8; 671.7 and 213.3 mg for diethylene glycol. Neither ethylene glycol nor diethylene glycol induced tumors at the injection site or away from the point of administration.

  14. Radiation curable oligomers

    International Nuclear Information System (INIS)

    Huemmer, T.F.; Edison, B.A.

    1977-01-01

    A process is described for the high energy radiation curing of oligomers for use as coatings. The method is particularly applicable to the reaction products of certain low molecular weight epoxy compounds and certain low molecular weight mono-hydroxy vinyl compounds having at least one vinylic unsaturation. The curable mixture is applied as a thin film and cured very quickly

  15. Electrorheology of aniline oligomers

    Czech Academy of Sciences Publication Activity Database

    Mrlík, M.; Sedlačík, M.; Pavlínek, V.; Bober, Patrycja; Trchová, Miroslava; Stejskal, Jaroslav; Sáha, P.

    2013-01-01

    Roč. 291, č. 9 (2013), s. 2079-2086 ISSN 0303-402X R&D Projects: GA ČR GA202/09/1626 Institutional support: RVO:61389013 Keywords : anilin e oligomers * polyaniline * electrorheology Subject RIV: JI - Composite Materials Impact factor: 2.410, year: 2013

  16. Development of ethylene direct oxidation process acetic acid new manufacturing method; Echiren jikisanho sakusan shinseizoho no kaihatsu

    Energy Technology Data Exchange (ETDEWEB)

    Sano, Ken' ichi; Nishino, Hiroshi; Iizuka, Yukio; Suzuki, Toshiro; Sasaki, Koji [Showa Denko Corp., Tokyo (Japan)

    1999-03-05

    Though existing acetic acid manufacturing which made the ethylene to be the starting material was two steps oxidation method of the via acetaldehyde, this study persons developed the new manufacturing method by the ethylenic direct oxyacid. In system of reaction, the following were realized by the development of palladium/heteropolyacid system composite catalyst: High activity and selectivity. In the purification system, the process of becoming, when the water consequentially forms azeotrope for the separation between acetic acid and extracting agent that extracting agent of alkyl acetate was done, that it was used and extracted, was developed. In the equipment material aspect, it is sufficient as a 316 stainless steel unlike other acetic acid manufacturing method. As an equipment scale, it has made to be the optium size for 5-200 thousand t/year, and that the location that it is more small-scale than methanol, carbonylation method and approaches the consumption ground is possible are features. The industrial plant for 100 thousand t/year based on this study carries out business operation in Oita since November, 1997. (translated by NEDO)

  17. Al or Si decorated graphene-oxide: A promising material for capture and activation of ethylene and acetylene

    Science.gov (United States)

    Esrafili, Mehdi D.; Dinparast, Leila

    2018-06-01

    In this work, quantum chemical calculations are performed to compare adsorption behavior of ethylene and acetylene molecules over Al- or Si-decorated graphene oxide (Al/Si-GO). The corresponding adsorption energies, geometrical parameters and net charge-transfer values are calculated using the dispersion-corrected DFT calculations. The obtained large adsorption energies of the Al and Si atoms over GO suggest that both Al-GO and Si-GO are stable enough to be used as a stable substrate to capture and activate ethylene or acetylene. The results show that the adsorption of C2H4 or C2H2 on Al-GO is more favorable than over Si-GO surface, mainly due to the orbital interactions between the adsorbate and surface. Also, the DFT calculations reveal that the interaction of C2H2 with both surfaces is stronger than that of C2H4. Our findings are applicable for future theoretical and experimental studies about the interaction of hydrocarbons with light metal decorated graphene-based materials as well as heterogeneous catalysis.

  18. Tuning thin-film electrolyte for lithium battery by grafting cyclic carbonate and combed poly(ethylene oxide) on polysiloxane.

    Science.gov (United States)

    Li, Jie; Lin, Yue; Yao, Hehua; Yuan, Changfu; Liu, Jin

    2014-07-01

    A tunable polysiloxane thin-film electrolyte for all-solid-state lithium-ion batteries was developed. The polysiloxane was synthesized by hydrosilylation of polymethylhydrosiloxane with cyclic [(allyloxy)methyl]ethylene ester carbonic acid and vinyl tris(2-methoxyethoxy)silane. (1) H NMR spectroscopy and gel-permeation chromatography demonstrated that the bifunctional groups of the cyclic propylene carbonate (PC) and combed poly(ethylene oxide) (PEO) were well grafted on the polysiloxane. At PC/PEO=6:4, the polysiloxane-based electrolyte had an ionic conductivity of 1.55 × 10(-4) and 1.50 × 10(-3)  S cm(-1) at 25 and 100 °C, respectively. The LiFePO4 /Li batteries fabricated with the thin-film electrolyte presented excellent cycling performance in the temperature range from 25 to 100 °C with an initial discharge capacity at a rate of 1 C of 88.2 and 140 mA h g(-1) at 25 and 100 °C, respectively. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  19. Synthesis of novel bis(perfluorophenyl azides) coupling agents: Evaluation of their performance by crosslinking of poly(ethylene oxide)

    KAUST Repository

    Mehenni, Hakim; Bakr, Osman

    2011-01-01

    Novel bis(perfluorophenyl azides) coupling agents, containing spacer arms from ethylene or ethylene glycol subunits, were successfully synthesized. Nitrenes photogenerated from these novel bis(PFPA) coupling agents were applied successfully

  20. A novel polygeneration process to co-produce ethylene and electricity from shale gas with zero CO2 emissions via methane oxidative coupling

    International Nuclear Information System (INIS)

    Khojasteh Salkuyeh, Yaser; Adams, Thomas A.

    2015-01-01

    Highlights: • Development of an ethylene plant from shale gases with zero CO 2 emissions. • Oxidative coupling of methane is used for the conversion of gas to ethylene. • Polygeneration strategy is used to improve the profitability of plant. - Abstract: A techno-economic analysis of a novel process to co-produce ethylene and electricity using a recently developed methane oxidative coupling catalyst is presented. Several design variants are considered, featuring the use of traditional gas turbines, chemical looping combustion, and 100% carbon dioxide capture. Mass and energy balance simulations were carried out using Aspen Plus simulations, and particle swarm optimization was used to determine the optimal process design under a variety of market scenarios. A custom model for the gas turbine section was used to ensure that the negative impacts of various cooling strategies were factored into the analysis. The results show that by synergistically co-producing power and ethylene using this catalyst, ethylene can be produced at costs close to traditional steam cracking methods with nearly zero carbon dioxide emissions, even when factoring in the relatively poor conversion and selectivity of the chosen catalyst

  1. Hybrid nanospheres formed by intermixed double-hydrophilic block copolymer poly(ethylene oxide)-block-poly(2-ethyloxazoline) with high content of metallacarboranes

    Czech Academy of Sciences Publication Activity Database

    Ďorďovič, V.; Uchman, M.; Procházka, K.; Zhigunov, Alexander; Pleštil, Josef; Nykänen, A.; Ruokolainen, J.; Matějíček, P.

    2013-01-01

    Roč. 46, č. 17 (2013), s. 6881-6890 ISSN 0024-9297 Institutional support: RVO:61389013 Keywords : poly(ethylene oxide)-block-poly(2-ethyloxazoline) * metallacarboranes Subject RIV: CD - Macromolecular Chemistry Impact factor: 5.927, year: 2013

  2. Observations of crystallization and melting in poly(ethylene oxide)/poly(methyl methacrylate) blends by hot-stage atomic-force microscopy

    NARCIS (Netherlands)

    Pearce, R.; Vancso, Gyula J.

    1998-01-01

    The binary blend of poly(ethylene oxide)/atactic poly(methyl methacrylate) is examined using hot-stage atomic-force microscopy (AFM) in conjunction with differential scanning calorimetry and optical microscopy. It was found possible to follow in real time the melting process, which reveals itself to

  3. Electrocatalytic oxidation of ethylene glycol at palladium-bimetallic nanocatalysts (PdSn and PdNi) supported on sulfonate-functionalised multi-walled carbon nanotubes

    CSIR Research Space (South Africa)

    Ramulifho, T

    2013-04-01

    Full Text Available Electrocatalytic oxidation of ethylene glycol (EG) in alkaline medium using nano-scaled palladium-based bimetallic catalysts (PdM, where M = Ni and Sn) supported on sulfonated multi-walled carbon nanotubes (SF-MWCNTs) is compared. The bimetallic...

  4. Sequential polymerization of ethylene oxide, ε-caprolactone and l-lactide: A one-pot metal-free route to tri- and pentablock terpolymers

    KAUST Repository

    Zhao, Junpeng; Pahovnik, David; Gnanou, Yves; Hadjichristidis, Nikolaos

    2014-01-01

    Metal-free polymerization of ethylene oxide (EO) catalyzed by a relatively mild phosphazene base (t-BuP2) was proven feasible, which enabled the one-pot sequential polymerization of EO, ε-caprolactone, and l-lactide. Using either 3-phenyl-1-propanol

  5. Poly(ethylene oxide)/poly(butylene terephthalate) segmented block copolymers: the effect of copolymer composition on physical properties and degradation behavior

    NARCIS (Netherlands)

    Deschamps, A.A.; Grijpma, Dirk W.; Feijen, Jan

    2001-01-01

    In this study, the influence of copolymer composition on the physical properties and the degradation behavior of thermoplastic elastomers based on poly(ethylene oxide) (PEO) and poly(butylene terephthalate) (PBT) segments is investigated. These materials are intended to be used in medical

  6. Comparison between Cellulose Nanocrystal and Cellulose Nanofibril Reinforced Poly(ethylene oxide) Nanofibers and Their Novel Shish-Kebab-Like Crystalline Structures

    Science.gov (United States)

    Xuezhu Xu; Haoran Wang; Long Jiang; Xinnan Wang; Scott A. Payne; J.Y. Zhu; Ruipeng Li

    2014-01-01

    Poly(ethylene oxide) (PEO) nanofiber mats were produced by electrospinning. Biobased cellulose nanocrystals (CNCs) and cellulose nanofibrils (CNFs) as reinforcement nanofillers were also added to the polymer to produce composite nanofiber mats. The effects of the two cellulose nanofillers on the rheological properties of the PEO solutions and the microstructure,...

  7. Water-soluble building blocks for terpyridine-containing supramolecular polymers : synthesis, complexation, and pH stability studies of poly(ethylene oxide) moieties

    NARCIS (Netherlands)

    Lohmeijer, B.G.G.; Schubert, U.S.

    2003-01-01

    Poly(ethylene oxide) of various molecular weights ([bar M ]n = 3 000, 5 200, 10 000, 16 500 g · mol-1) has been modified with terpyridine end groups as building blocks for water-soluble metallo-supramolecular polymers. Metallo-supramolecular A-A homopolymers have been prepared and characterized by

  8. Nanosized amorphous calcium carbonate stabilized by poly(ethylene oxide)-b-poly(acrylic acid) block copolymers.

    Science.gov (United States)

    Guillemet, Baptiste; Faatz, Michael; Gröhn, Franziska; Wegner, Gerhard; Gnanou, Yves

    2006-02-14

    Particles of amorphous calcium carbonate (ACC), formed in situ from calcium chloride by the slow release of carbon dioxide by alkaline hydrolysis of dimethyl carbonate in water, are stabilized against coalescence in the presence of very small amounts of double hydrophilic block copolymers (DHBCs) composed of poly(ethylene oxide) (PEO) and poly(acrylic acid) (PAA) blocks. Under optimized conditions, spherical particles of ACC with diameters less than 100 nm and narrow size distribution are obtained at a concentration of only 3 ppm of PEO-b-PAA as additive. Equivalent triblock or star DHBCs are compared to diblock copolymers. The results are interpreted assuming an interaction of the PAA blocks with the surface of the liquid droplets of the concentrated CaCO3 phase, formed by phase separation from the initially homogeneous reaction mixture. The adsorption layer of the block copolymer protects the liquid precursor of ACC from coalescence and/or coagulation.

  9. Effect of graphite loading on the electrical and mechanical properties of Poly (Ethylene Oxide)/Poly (Vinyl Chloride) polymer films

    Science.gov (United States)

    Hajar, M. D. S.; Supri, A. G.; Hanif, M. P. M.; Yazid, M. I. M.

    2017-10-01

    In this study, films consisting of a blend of poly (ethylene oxide)/poly (vinyl chloride) (PEO/PVC) and a conductive filler, graphite were prepared and characterized for their mechanical and electrical properties. Solid polymer blend films based on PEO/PVC (50/50 wt%/wt%) with different graphite loading were prepared by using solution casting technique. Electrical conductivity results discovered the conductivity increased with increasing of filler loading. However, increasing amount of graphite loading led to a decreased in tensile strength and young’s modulus of PEO/PVC/Graphite polymer films. The dispersion of graphite and mechanism of conductive path in the polymer films were also investigated by scanning electron microscopy (SEM). The morphology of the PEO/PVC/Graphite polymer films shows that agglomeration occurred to complete the connection of conductive path, thus improving the conductivity behavior of the polymer films.

  10. Comparative effects of gamma irradiation and ethylene oxide fumigation on some chemical quality of white ginseng powder

    International Nuclear Information System (INIS)

    Kwon, J.H.; Byun, M.W.; Cho, H.O.; Han, B.H.

    1994-01-01

    Ginseng saponins and proximate components were considerably resistant to both gamma irradiation at less than 10 kGy and commercial ethylene oxide cycle, while sulfur-containing amino acids, reducing sugar, pH, and acidity of white ginseng powder were significantly changed by EO fumigation. The contents of saponins, reducing sugar, pH and acidity were relatively liable to change under the higher relative humidity (90%), especially in the non-treated control sample. However, irradiated samples at optimum-dose range (5 to 10 kGy) depending on the microbial load following airtight packaging showed a good chemical quality for 7 months of storage at 30 pm 2 deg. C irrespective of relative humidity

  11. Comparative study and histomorphometric analysis of bone allografts lyophilized and sterilized by autoclaving, gamma irradiation and ethylene oxide in rats

    Directory of Open Access Journals (Sweden)

    Otavio Machado de Almeida

    2013-01-01

    Full Text Available PURPOSE: To compare three sterilization methods (autoclave, gamma irradiation and ethylene oxide over non demineralized lyophilized bone allografts. METHODS: Bone allografts were implanted on paravertebral muscles of 21 rats. After 30 days animals were sacrificed and grafts underwent comparative analysis regarding histomorphometric and macroscopic parameters. RESULTS: Allografts that underwent the three sterilization methods presents similar weight gain, cortical thickness similar to control group, and less fibrosis than the control group. Grafts that underwent sterilization in autoclave presented less presence of multinucleated giant cells, although not statistically significant. There was also no statistically significant difference regarding mineralization on the three groups. CONCLUSION: The three sterilization methods cause similar effects on bone allografts regarding macroscopic and histomorphometric parameters.

  12. [Complex formation between alpha-chymotrypsin and block copolymers based on ethylene and propylene oxide, induced by high pressure].

    Science.gov (United States)

    Topchieva, I N; Sorokina, E M; Kurganov, B I; Zhulin, V M; Makarova, Z G

    1996-06-01

    A new method of formation of non-covalent adducts based on an amphiphilic diblock copolymer of ethylene and propylene oxides with molecular mass of 2 kDa and alpha-chymotrypsin (ChT) under high pressure, has been developed. The composition of the complexes corresponds to seven polymer molecules per one ChT molecule in the pressure range of 1.1 to 400 MPa. The complexes fully retain the catalytic activity. Kinetic constants (Km and kcat) for enzymatic hydrolysis of N-benzoyl-L-tyrosine ethyl ester catalyzed by the complexes are identical with the corresponding values for native ChT. Analysis of kinetics of thermal inactivation of the complexes revealed that the constant of the rate of the slow inactivation step is markedly lower than for ChT.

  13. Biological compatibility test on films of added SEO [poly(dimethyl siloxane)-co-poly(ethylene oxide)] PVP

    International Nuclear Information System (INIS)

    Rogero, Sizue O.; Souza-Bazzi, Aurea de; Higa, Olga Z.

    1999-01-01

    Membranes composed by polyvinylpyrrolidone (PVP), agar and water crosslinked by ionizing radiation, can have the mechanical properties improved by the addition of copolymers. Due to the hydrophilic property also by the medical grade as it is supplied, the copolymer poly(dimethyl siloxane)-co-poly(ethylene oxide) (SEO) was added to the PVP membranes. Varied concentrations of SEO were used in the preparation of PVP membranes by electron beam irradiation at dose rate of 25 kGy. For testing the bicompatibility of the SEO composed membrane the in vitro assay of cytotoxicity, with Chinese Hamster Ovary cells (CHO), was carried out. However, the membranes showed a cytotoxic characteristic in cell culture, which was stronger as the amount of SEO increased in the composition. (author)

  14. Comparative effects of gamma irradiation and ethylene oxide fumigation on sorption properties and microbiological quality of white ginseng powder

    International Nuclear Information System (INIS)

    Kwon, J.H.; Byun, M.W.; Lee, S.J.

    1994-01-01

    The microbial populations of exportable and domestic white ginseng powders, which have been problems in quality control, were higher than the legally-permissive level of microorganisms as 5x10 4 g in total bacteria and as negative coliforms. Various microorganisms contaminated in the sample were effectively decontaminated by gamma irradiation at below 10 kGy as well as ethylene oxide (EO) fumigation. The radiosensitivity of microorganisms was the highest in coliforms, followed by molds and aerobic bacteria (D 10 : 1.25 kGy). The good microbiological quality could be retained in white ginseng powders for more than 7 months of storage at 30 per mille 2 deg. C irrespective of relative humidities if products are prepared with a lower moisture content below 10% and treated by gamma irradiation at 5 to 10 kGy in an airtight packaging

  15. Novel poly(vinylidene fluoride-trifluoroethylene)/poly(ethylene oxide) blends for battery separators in lithium-ion applications

    International Nuclear Information System (INIS)

    Costa, C.M.; Nunes-Pereira, J.; Rodrigues, L.C.; Silva, M.M.; Ribelles, J.L. Gomez; Lanceros-Méndez, S.

    2013-01-01

    Highlights: ► New P(VDF-TrFE)/PEO polymer blends were prepared for battery separator. ► The porosity and hydrophilicity degree are tailored within this blend. ► Ionic conductivity depends on PEO presence and is stable with temperature. ► High ionic conductivity of 0.25 mS cm −1 for the 60/40 blend. -- Abstract: Polymer blends based on poly(vinylidene fluoride-trifluoroethylene)/poly(ethylene oxide), P(VDF-TrFE)/PEO for Li-ion battery separator applications have been prepared through solvent casting technique. The microstructure, hydrophilicity and electrolyte uptake strongly depend on PEO content within the blend. The best value of ionic conductivity at room temperature was 0.25 mS cm −1 for the 60/40 membrane. The membranes are electrochemically stable

  16. Fabrication and Super-Antibacterial Property of Nanosilver/Sericin/Poly(ethylene oxide Nanofibers through Electrospinning-Combined Postdeposition Method

    Directory of Open Access Journals (Sweden)

    Jia Li

    2016-01-01

    Full Text Available Nanosilver particle has been used in the nanofiber mats by mixing the nanosilver with the spinning solution for improving the antibacterial property. Although studies have shown that the antibacterial property of nanofiber mats gets increasing, the higher silver content and the larger released resistance of nanosilver from nanofiber mats are obvious. Here, the electrospinning-combined postdeposition method was used to prepare the nanosilver/sericin/poly(ethylene oxide (Ag/SS/PEO nanofiber mats and the bacterial reduction rates against Staphylococcus aureus (S. aureus and Escherichia coli (E. coli were analyzed. We found that the Ag/SS/PEO nanofiber mats were excellent antibacterial properties at the lower silver content and the bacterial reduction rates against S. aureus and E. coli all reached above 99.99%. Our data suggests that the antibacterial property can be improved by introducing the electrospinning-combined postdeposition method.

  17. Suggestion for search of ethylene oxide (c-C2H4O) in a cosmic object

    Science.gov (United States)

    Sharma, M. K.; Sharma, M.; Chandra, S.

    2018-05-01

    Ethylene oxide (c-C2H4O) and its isomer acetaldehyde (CH3CHO) are important organic molecules because of their potential role in the formation of amino acids. The c-C2H4O molecule is a b-type asymmetric top molecule and owing to half-spin of each of the four hydrogen atoms, it has two distinct ortho (nuclear spin one) and para (nuclear spin zero and two) species. It has been detected in the Sgr B2N. Using the rotational and centrifugal distortion constants along with the electric dipole moment, we have calculated energies of 100 rotational levels of each of the ortho and para species of c-C2H4O molecule and the Einstein A-coefficients for radiative transitions between the levels. The values of Einstein A-coefficients along with the scaled values for the collisional rate coefficients are used for solving a set of statistical equilibrium equations coupled with the equations of radiative transfer. Brightness-temperatures of five rotational transitions of each of the ortho and para species of c-C2H4O molecule are investigated. Out of these ten transitions, three transitions are found to show the anomalous absorption and rest seven are found to show the emission feature. We have also investigated seven transitions observed unblended in the Sgr B2(N). We have found that the transitions 3_{3 0} - 3_{2 1} (23.134 GHz), 2_{2 0} - 2_{1 1} (15.603 GHz), 3_{3 1} - 3_{2 2} (39.680 GHz) and 1_{1 1} - 0_{0 0} (39.582 GHz) may play important role for the identification of ethylene oxide in a cosmic object.

  18. SCC-TB, DFT/B3LYP, MP2, AM1, PM3 and RHF study of ethylene oxide and propylene oxide structures, VA and VCD spectra

    DEFF Research Database (Denmark)

    Jalkanen, Karl J.; Frimand, Kenneth

    2002-01-01

    -binding method for equilibrium structures, VA and VCD spectra of ethylene oxide and propylene oxide in the gas-phase. Comparison to conventional methods AM1, PM3, MP2, RHF and DFT/B3LYP is carried out. We report results over a wider range of frequencies than previous work. In particular, we find indications...... that the self-consistent-charge tight-binding method, combined with DFT/B3LYP atomic polar tensors and atomic axial tensors, compares favourably with competing methods tendency to overestimate the location of spectral peaks with respect to frequencies, the latter observation being most pronounced in the higher...... frequency regions. Our findings produce additional support for the self-consistent-charge tight-binding method as a fast computational method for small and larger molecules, however, also that improved parameterisations are needed to reach accuracies of MP2 and DFT/B3LYP. (C) 2002 Elsevier Science B.V. All...

  19. Poly(ethylene oxide)-block-poly(glutamic acid) coated maghemite nanoparticles: in vitro characterization and in vivo behaviour

    International Nuclear Information System (INIS)

    Kaufner, L; Cartier, R; Wuestneck, R; Fichtner, I; Pietschmann, S; Bruhn, H; Schuett, D; Thuenemann, A F; Pison, U

    2007-01-01

    Positively charged superparamagnetic iron oxide (SPIO) particles of maghemite were prepared in aqueous solution and subsequently stabilized with poly(ethylene oxide)-block-poly(glutamic acid) (PEO-PGA) at a hydrodynamic diameter of 60 nm. Depending on the amount of PEO-PGA used, this is accompanied by a switching of their zeta potentials from positive to negative charge (-33 mV). As a prerequisite for in vivo testing, the PEO-PGA coated maghemite nanoparticles were evaluated to be colloidally stable in water and in physiological salt solution for longer than six months as well in various buffer systems under physiological pH and salt conditions (AFM, dynamic light scattering). We excluded toxic effects of the PEO-PGA coated maghemite nanoparticles. We demonstrated by in vivo MR-imaging and 111 In measurements a biodistribution of the nanoparticles into the liver comparable to carboxydextran coated superparamagnetic iron oxide nanoparticles (Resovist[reg]) as a reference nanoscaled MRI contrast medium. This was enforced by a detailed visualization of our nanoparticles by electron microscopy of liver tissue sections. Furthermore, our results indicate that 15% of the injected PEO-PGA coated maghemite nanoparticles circulate in the blood compartment for at least 60 min after i.v. application

  20. Effects of UV Aging on the Cracking of Titanium Oxide Layer on Poly(ethylene terephthalate) Substrate: Preprint

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Chao; Gray, Matthew H.; Tirawat, Robert; Larsen, Ross E.; Chen, Fangliang

    2016-04-18

    Thin oxide and metal films deposited on polymer substrates is an emerging technology for advanced reflectors for concentrated solar power applications, due to their unique combination of light weight, flexibility and inexpensive manufacture. Thus far, there is little knowledge on the mechanical integrity or structural persistence of such multi-layer thin film systems under long-term environmental aging. In this paper, the cracking of a brittle titanium dioxide layer deposited onto elasto-plastic poly(ethylene terephthalate) (PET) substrate is studied through a combination of experiment and modeling. In-situ fragmentation tests have been conducted to monitor the onset and evolution of cracks both on pristine and on samples aged with ultraviolet (UV) light. An analytical model is presented to simulate the cracking behavior and to predict the effects of UV aging. Based on preliminary experimental observation, the effect of aging is divided into three aspects and analyzed independently: mechanical property degradation of the polymer substrate; degradation of the interlayer between substrate and oxide coating; and internal stress-induced cracks on the oxide coating.

  1. Aniline oligomers versus polyaniline

    Czech Academy of Sciences Publication Activity Database

    Stejskal, Jaroslav; Trchová, Miroslava

    2012-01-01

    Roč. 61, č. 2 (2012), s. 240-251 ISSN 0959-8103 R&D Projects: GA AV ČR IAA400500905; GA AV ČR IAA100500902; GA ČR GA203/08/0686; GA ČR GA202/09/1626 Institutional research plan: CEZ:AV0Z40500505 Keywords : polyaniline * anilin e oligomers * anilin e Subject RIV: CD - Macromolecular Chemistry Impact factor: 2.125, year: 2012

  2. Preparation and properties of poly(ethylene oxide) gel filled polypropylene separators and their corresponding gel polymer electrolytes for Li-ion batteries

    International Nuclear Information System (INIS)

    Li Hao; Ma Xiaoting; Shi Junli; Yao Zhikan; Zhu Baoku; Zhu Liping

    2011-01-01

    Poly(ethylene oxide) (PEO) filled polypropylene separators (GFPSs) are designed by means of thermal cross-linking of entrapped poly(ethylene glycol) methyl ether acrylate (PEGMEA) and poly(ethylene glycol) diacrylate (PEGDA) as gel constituents. The intrinsic properties of GFPS and their corresponding gel polymer electrolytes (GPE) are characterized by DSC, SEM, contact angle and electrochemical methods. It is found the stability of liquid electrolyte uptake in GPE could be improved obviously. For the GPE prepared from GFPS with filled polyether content of 14.3 wt%, the ionic conductivity could reach 1.12 x 10 -3 S cm -1 while the electrochemically stable window reach 5.0 V (vs. Li/Li + ). These primary results show great promise of this simple method to prepare GPE for practical application in lithium ion batteries.

  3. Preparation and properties of poly(ethylene oxide) gel filled polypropylene separators and their corresponding gel polymer electrolytes for Li-ion batteries

    Energy Technology Data Exchange (ETDEWEB)

    Li Hao; Ma Xiaoting; Shi Junli; Yao Zhikan [Department of Polymer Science and Engineering, Engineering Center of Membrane and Water Treatment, Key Laboratory of Macromolecule Synthesis and Functionalization (EMC), Zhejiang University, Hangzhou 310027 (China); Zhu Baoku, E-mail: zhubk@zju.edu.c [Department of Polymer Science and Engineering, Engineering Center of Membrane and Water Treatment, Key Laboratory of Macromolecule Synthesis and Functionalization (EMC), Zhejiang University, Hangzhou 310027 (China); Zhu Liping [Department of Polymer Science and Engineering, Engineering Center of Membrane and Water Treatment, Key Laboratory of Macromolecule Synthesis and Functionalization (EMC), Zhejiang University, Hangzhou 310027 (China)

    2011-02-15

    Poly(ethylene oxide) (PEO) filled polypropylene separators (GFPSs) are designed by means of thermal cross-linking of entrapped poly(ethylene glycol) methyl ether acrylate (PEGMEA) and poly(ethylene glycol) diacrylate (PEGDA) as gel constituents. The intrinsic properties of GFPS and their corresponding gel polymer electrolytes (GPE) are characterized by DSC, SEM, contact angle and electrochemical methods. It is found the stability of liquid electrolyte uptake in GPE could be improved obviously. For the GPE prepared from GFPS with filled polyether content of 14.3 wt%, the ionic conductivity could reach 1.12 x 10{sup -3} S cm{sup -1} while the electrochemically stable window reach 5.0 V (vs. Li/Li{sup +}). These primary results show great promise of this simple method to prepare GPE for practical application in lithium ion batteries.

  4. Adsorption of ethylene carbonate on lithium cobalt oxide thin films: A synchrotron-based spectroscopic study of the surface chemistry

    Science.gov (United States)

    Fingerle, Mathias; Späth, Thomas; Schulz, Natalia; Hausbrand, René

    2017-11-01

    The surface chemistry of cathodic lithium cobalt oxide (LiCoO2) in contact with the Li-ion battery solvent ethylene carbonate (EC) was studied via synchrotron based soft X-ray photoelectron spectroscopy (SXPS). By stepwise in-situ adsorption of EC onto an rf-magnetron sputtered LiCoO2 thin film and consecutive recording of SXPS spectra, the chemical and electronic properties of the interface were determined. EC partially decomposes and forms a predominantly organic adlayer. Prolonged exposure results in the formation of a condensed EC layer, demonstrating that the decomposition layer has passivating properties. Lithium ions deintercalate from the electrode and are dissolved in the adsorbate phase, without forming a large amount of Li-containing reaction products, indicating that electrolyte reduction remains limited. Due to a large offset between the LiCoO2 valence band and the EC HOMO, oxidation of EC molecules is unlikely, and should require energy level shifts due to interaction or double layer effects for real systems.

  5. Differences in the adsorption behaviour of poly(ethylene oxide) copolymers onto model polystyrene nanoparticles assessed by isothermal titration microcalorimetry correspond to the biological differences.

    Science.gov (United States)

    Stolnik, S; Heald, C R; Garnett, M G; Illum, L; Davis, S S

    2005-01-01

    The adsorption behaviour of a tetrafunctional copolymer of poly (ethylene oxide)-poly (propylene oxide) ethylene diamine (commercially available as Poloxamine 908) and a diblock copolymer of poly (lactic acid)-poly (ethylene oxide) (PLA/PEG 2:5) onto a model colloidal drug carrier (156 nm sized polystyrene latex) is described. The adsorption isotherm, hydrodynamic thickness of the adsorbed layers and enthalpy of the adsorption were assessed. The close similarity in the conformation of the poly (ethylene oxide) (PEO) chains (molecular weight 5,000 Da) in the adsorbed layers of these two copolymers was demonstrated by combining the adsorption data with the adsorbed layer thickness data. In contrast, the results from isothermal titration microcalorimetry indicated a distinct difference in the interaction of the copolymers with the polystyrene colloid surface. Poloxamine 908 adsorption to polystyrene nanoparticles is dominated by an endothermic heat effect, whereas, PLA/PEG 2:5 adsorption is entirely an exothermic process. This difference in adsorption behaviour could provide an explanation for differences in the biodistribution of Poloxamine 908 and PLA/PEG 2:5 coated polystyrene nanoparticles observed in previous studies. A comparison with the interaction enthalpy for several other PEO-containing copolymers onto the same polystyrene colloid was made. The results demonstrate the importance of the nature of the anchoring moiety on the interaction of the adsorbing copolymer with the colloid surface. An endothermic contribution is found when an adsorbing molecule contains a poly (propylene oxide) (PPO) moiety (e.g. Poloxamine 908), whilst the adsorption is exothermic (i.e. enthalpy driven) for PEO copolymers with polylactide (PLA/PEG 2:5) or alkyl moieties.

  6. Ethylene glycol oxidation on Pt and Pt-Ru nanoparticle decorated polythiophene/multiwalled carbon nanotube composites for fuel cell applications

    International Nuclear Information System (INIS)

    Selvaraj, Vaithilingam; Alagar, Muthukaruppan

    2008-01-01

    A novel supporting material containing polythiophene (PTh) and multiwalled carbon nanotubes (MWCNTs) (PTh-CNTs) is prepared by in situ polymerization of thiophene on carbon nanotubes using FeCl 3 as oxidizing agent under sonication. The prepared polythiophene/CNT composites are further decorated with Pt and Pt-Ru nanoparticles by chemical reduction of the corresponding metal salts using HCHO as reducing agent at pH = 11 (Pt/PTh-CNT and Pt-Ru/PTh-CNT). The fabricated composite films decorated with nanoparticles were investigated towards the electrochemical oxidation of ethylene glycol (EG). The presence of carbon nanotubes in conjugation with a conducting polymer produces a good catalytic effect, which might be due to the higher electrochemically accessible surface areas, electronic conductivity and easier charge-transfer at polymer/electrolyte interfaces, which allows higher dispersion of Pt and Pt-Ru nanoparticles. Such nanoparticle modified PTh-CNT electrodes exhibit better catalytic behavior towards ethylene glycol oxidation. Results show that Pt/PTh-CNT and Pt-Ru/PTh-CNT modified electrodes show enhanced electrocatalytic activity and stability towards the electro-oxidation of ethylene glycol than the Pt/PTh electrodes, which shows that the composite film is more promising for applications in fuel cells

  7. Reaction of oxygen with γ, δ-ethylenic phenylhydrazones. Model reaction of end-group behavior in phenylhydrazine-accelerated oxidation of natural rubber

    International Nuclear Information System (INIS)

    El Hamdaoui, A.; Reyx, D.; Campistron, I.

    1995-01-01

    An accurate definition of terminal groups of chains in the liquid polymers obtained by the phenylhydrazine-accelerated oxidation of natural rubber is needed. The object of the work was to use model molecules to explore the behavior of γ,δ-ethylenic methylketone phenylhydrazone end-groups in oxidation conditions. We have investigated the synthesis and characterization of models of these hypothetical end-groups, methylketones and phenones 1, their phenylhydrazones 2, the α-(phenyldiazenyl)hydroperoxides 3 resulting from reaction of 2 with oxygen, and the α-(phenyldiazenyl)alcohols 4 as characteristic derivatives of 3 or as models of possible reduced structures in oxidized liquid natural rubber. Three original syntheses of γ,δ-ethylenic ketones were carried out. In the case of γ,δ-ethylenic phenylhydrazones, the oxidation led to the expected α-(phenyldiazenyl)hydroperoxides and to epoxide derivatives of α-(phenyldiazenyl)alcohols 5 and ketones 6. An intramolecular mechanism is proposed. The results are used to predict the possibilities of identification of the corresponding end-groups in liquid rubbers produced in this way. (authors). 16 refs., 12 figs., 3 tabs

  8. Kinetic Modeling of the Release of Ethylene Oxide from Sterilized Plastic Containers and its Interaction with Monoclonal Antibodies.

    Science.gov (United States)

    Yu, Bryan Lei; Han, Jun; Hammond, Matthew; Wang, Xuemei; Zhang, Qingchun; Clausen, Andrew; Forster, Ronald; Eu, Mingda

    Ethylene oxide (ETO) is commonly used to sterilize plastic containers, but the effects of residual amounts left after sterilization on protein therapeutics are still not well understood. Here we focus primarily on the factors that influence concentrations of ETO migrating from ETO-treated plastic containers into aqueous solution. A study was designed to investigate the kinetics of this process at various temperatures, and the kinetic data could be fit with a model based on a combination of Fickean diffusion and first-order chemical reaction (to account for observed hydrolysis of ETO). The diffusion and reaction rate constants thus obtained obey Arrhenius-like temperature dependence. These results indicate that for analytical methods involving extraction into water, measurements of residual ETO in a container must account for the effects of ETO hydrolysis. Further, the effects of salt concentration and pH of the fluid in the container on accumulated ETO levels were explored. Finally, interactions of ETO with anti-streptavidin (AntiSA) Immunoglobulin G1 (IgG1) and IgG2 antibodies were studied, with ETO adducts found on all methionine residues when incubated in solutions spiked with ETO at concentrations that could be reached (based on the kinetic studies) in ETO-treated plastic vials. Overall, the likelihood of observable ETO-protein modifications upon storage in ETO-sterilized containers will depend on a complex interplay of protein properties, formulation details, storage conditions, and amount of residual ETO initially in the container. Ethylene oxide (ETO) is commonly used to sterilize plastic containers, but the effects of residual amounts left after sterilization on protein therapeutics are still not well understood. Here we describe experiments exploring the factors that influence concentrations of ETO migrating from ETO-treated plastic containers into aqueous solution over time. Additionally, interactions of ETO with model antibodies were studied, with ETO

  9. Development of Iron-Chelating Poly(ethylene terephthalate) Packaging for Inhibiting Lipid Oxidation in Oil-in-Water Emulsions.

    Science.gov (United States)

    Johnson, David R; Tian, Fang; Roman, Maxine J; Decker, Eric A; Goddard, Julie M

    2015-05-27

    Foods such as bulk oils, salad dressings, and nutritionally fortified beverages that are susceptible to oxidative degradation are often packaged in poly(ethylene terephthalate) (PET) bottles with metal chelators added to the food to maintain product quality. In the present work, a metal-chelating active packaging material is designed and characterized, in which poly(hydroxamic acid) (PHA) metal-chelating moieties were grafted from the surface of PET. Biomimetic PHA groups were grafted in a two-step UV-initiated process without the use of a photoinitiator. Surface characterization of the films by attenuated total reflective Fourier transform infrared spectroscopy (ATR-FTIR) and scanning electron microscopy (SEM) suggested successful grafting and conversion of poly(hydroxyethyl acrylate) (PHEA) to PHA chelating moieties from the surface of PET. Colorimetric (ferrozine) and inductively coupled plasma mass spectroscopy (ICP-MS) assays demonstrated the ability of PET-g-PHA to chelate iron in a low-pH (3.0) environment containing a competitive metal chelator (citric acid). Lipid oxidation studies demonstrated the antioxidant activity of PET-g-PHA films in inhibiting iron-promoted oxidation in an acidified oil-in-water (O/W) emulsion model system (pH 3.0). Particle size and ζ-potential analysis indicated that the addition of PET-g-PHA films did not affect the physical stability of the emulsion system. This work suggests that biomimetic chelating moieties can be grafted from PET and effectively inhibit iron-promoted degradation reactions, enabling removal of metal-chelating additives from product formulations.

  10. Synthesis of polymer electrolyte membranes from cellulose acetate/poly(ethylene oxide)/LiClO{sub 4} for lithium ion battery application

    Energy Technology Data Exchange (ETDEWEB)

    Nurhadini,, E-mail: nur-chem@yahoo.co.id; Arcana, I Made, E-mail: arcana@chem.itb.ac.id [Inorganic and Physical Chemistry Research Division, Faculty of Mathematics and Natural Sciences, Institiut Teknologi Bandung, Jalan Ganesha 10, Bandung 40132 (Indonesia)

    2015-09-30

    This study was conducted to determine the effect of cellulose acetate on poly(ethylene oxide)-LiClO{sub 4} membranes as the polymer electrolyte. Cellulose acetate is used as an additive to increase ionic conductivity and mechanical property of polymer electrolyte membranes. The increase the percentage of cellulose acetate in membranes do not directly effect on the ionic conductivity, and the highest ionic conductivity of membranes about 5,7 × 10{sup −4} S/cm was observed in SA/PEO/LiClO{sub 4} membrane with cellulose ratio of 10-25% (w/w). Cellulose acetate in membranes increases mechanical strength of polymer electrolyte membranes. Based on TGA analysis, this polymer electrolyte thermally is stable until 270 °C. The polymer electrolyte membrane prepared by blending the cellulose acetate, poly(ethylene oxide), and lithium chlorate could be potentially used as a polymer electrolyte for lithium ion battery application.

  11. Sequential polymerization of ethylene oxide, ε-caprolactone and l-lactide: A one-pot metal-free route to tri- and pentablock terpolymers

    KAUST Repository

    Zhao, Junpeng

    2014-01-01

    Metal-free polymerization of ethylene oxide (EO) catalyzed by a relatively mild phosphazene base (t-BuP2) was proven feasible, which enabled the one-pot sequential polymerization of EO, ε-caprolactone, and l-lactide. Using either 3-phenyl-1-propanol or water as an initiator, the corresponding triblock or pentablock terpolymers were easily prepared. © 2014 the Partner Organisations.

  12. Thermoresponsive behaviour of terpolymers containing poly(ethylene oxide), poly(2-ethyl-2-oxazoline) and poly(.epsilon.-caprolactone) blocks in aqueous solutions: an NMR study

    Czech Academy of Sciences Publication Activity Database

    Konefal, Rafal; Spěváček, Jiří; Jäger, Eliezer; Petrova, Svetlana

    2016-01-01

    Roč. 294, č. 11 (2016), s. 1717-1726 ISSN 0303-402X R&D Projects: GA ČR(CZ) GA15-13853S; GA MŠk(CZ) 7F14009 Institutional support: RVO:61389013 Keywords : thermoresponsive polymer * terpolymer containing poly(ethylene oxide), poly(2-ethyl-2-oxazoline) and poly(epsilon-caprolactone) blocks * nanoparticles Subject RIV: CD - Macromolecular Chemistry Impact factor: 1.723, year: 2016

  13. Preparation of reinforced poly(ethylene oxide) blend hydrogel films containing a drug and assessment of their properties

    International Nuclear Information System (INIS)

    Yang Zhanshan; Zhu Nankang; Yang Shuqin

    1999-01-01

    Reinforced poly(ethylene oxide) blend hydrogen films containing mafenide acetate were prepared by using two freezing-thawing cycles and the irradiation crosslinking technique, and their properties and the drug release were assessed. The results showed that the tensile strength of the reinforced PEO blend hydrogel films increased significantly (p < 0.01), the gel fraction and the elongation at break of the films increased slightly as compared with those formed by the irradiation without the freezing-thawing treatment, indicating that the mechanical properties of the PEO blend hydrogel films can be improved by the freezing-thawing cycles. The reinforced films possessed an ideal flexibility, crosslinking density and elasticity as wound dressings. Swelling studies showed that the equilibrium water content of the hydrogel films expressed in the degree of swelling decreased significantly (p < 0.01), suggesting that a significant structural rearrangement of the films occurred during the freezing process. The structural densification resulted in the increase of the mechanical strength of the hydrogel films. The hydrogels formed by the irradiation at doses of 40 kGy were comparatively stronger. Release studies were run on the reinforced hydrogels with mafenide acetate which was incorporated before the freezing-thawing treatment. Release was followed over seven days. The drug transport was controlled by a regular diffusion model

  14. Phase behavior of poly(dimethylsiloxane)-poly(ethylene oxide) amphiphilic block and graft copolymers in compressed carbon dioxide

    International Nuclear Information System (INIS)

    Stoychev, Ivan; Peters, Felix; Kleiner, Matthias; Sadowski, Gabriele; Clerc, Sebastien; Ganachaud, Francois; Chirat, Mathieu; Lacroix-Desmazes, Patrick; Fournel, Bruno

    2012-01-01

    The phase behavior of triblock and graft-type poly(dimethylsiloxane) (PDMS)-poly(ethylene oxide) (PEO) copolymer surfactants has been investigated in compressed carbon dioxide (CO 2 ). For this purpose, cloud-point pressures have been measured in the pressure and temperature range from P=10 to 40 MPa and from T= 293 to 338 K. The Perturbed-Chain Statistical Associating Fluid Theory (PC-SAFT) equation of state (EoS) has been applied to model the experimental data in order to better understand the influence of the structure of the copolymers on the phase behavior of the system. The pure-component parameters for PDMS have been fitted originally to PDMS/n-pentane system. These parameters are successfully applied for PDMS in CO 2 by adjusting a temperature-dependent binary interaction parameter. The phase behavior of the triblock copolymers was successfully predicted by PC-SAFT. In contrast, the phase behavior of the graft copolymers was difficult to predict accurately at this stage. (authors)

  15. Supramolecular Nanostructures Based on Cyclodextrin and Poly(ethylene oxide: Syntheses, Structural Characterizations and Applications for Drug Delivery

    Directory of Open Access Journals (Sweden)

    Yue Zheng

    2016-05-01

    Full Text Available Cyclodextrins (CDs have been extensively studied as drug delivery carriers through host–guest interactions. CD-based poly(pseudorotaxanes, which are composed of one or more CD rings threading on the polymer chain with or without bulky groups (or stoppers, have attracted great interest in the development of supramolecular biomaterials. Poly(ethylene oxide (PEO is a water-soluble, biocompatible polymer. Depending on the molecular weight, PEO can be used as a plasticizer or as a toughening agent. Moreover, the hydrogels of PEO are also extensively studied because of their outstanding characteristics in biological drug delivery systems. These biomaterials based on CD and PEO for controlled drug delivery have received increasing attention in recent years. In this review, we summarize the recent progress in supramolecular architectures, focusing on poly(pseudorotaxanes, vesicles and supramolecular hydrogels based on CDs and PEO for drug delivery. Particular focus will be devoted to the structures and properties of supramolecular copolymers based on these materials as well as their use for the design and synthesis of supramolecular hydrogels. Moreover, the various applications of drug delivery techniques such as drug absorption, controlled release and drug targeting based CD/PEO supramolecular complexes, are also discussed.

  16. Effect of polyethyleneglycol on CH{sub 4} permeation through poly(amide-b-ethylene oxide)-based nanocomposite membranes

    Energy Technology Data Exchange (ETDEWEB)

    Asghari, Morteza, E-mail: asghari@kashanu.ac.ir [Separation Processes Research Group (SPRG), University of Kashan, Kashan (Iran, Islamic Republic of); Energy Research Institute, University of Kashan, Ghotb-e-Ravandi Avenue, Kashan (Iran, Islamic Republic of); Mahmudi, Amir; Zargar, Vida [Separation Processes Research Group (SPRG), University of Kashan, Kashan (Iran, Islamic Republic of); Khanbabaei, Ghader [Polymer Science and Technology Division, Research Institute of Petroleum Industry, Tehran (Iran, Islamic Republic of)

    2014-11-01

    Graphical abstract: - Highlights: • A three-phase polymer/liquid/solid (PEBA/PEG/zeolite X) membrane was fabricated. • Nanocrystalline zeolite X was used as filler to stabilize membrane polymeric matrix. • Introducing zeolite to PEBA matrix caused its total free volume to decrease. • A gradual decrease with pressure was observed in CH{sub 4} permeability for the membranes. • In all the experiments, operating pressures varied from 2 to 8 bar. - Abstract: A three-phase polymer/liquid/solid poly(amide-b-ethylene oxide) (PEBA)/polyethylene glycol (PEG)/zeolite X was fabricated and its gas permeability was investigated. CH{sub 4} permeability of neat PEBA, two-phase PEBA/NaX and three-phase PEBA/PEG/NaX were compared for different pressures within the range of 2–8 bar. The fabricated membranes were structurally characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM) and atomic force microscope (AFM). SEM images showed that the zeolite grain size was homogeneously smaller than 2 μm. They also revealed the dense structures of the membranes and no pores were observed at these magnifications. AFM surface images indicated that the membranes surface roughness increased significantly with increasing zeolite loading. CH{sub 4} permeability for single-, two- and three-phase membranes decreased from 3.13 to 2.81, from 3.96 to 2.31 and from 2.67 to 2.14 barrer, respectively.

  17. Enhancement of stiffness, strength, ductility and toughness of poly(ethylene oxide) using phenoxy-grafted multiwalled carbon nanotubes

    International Nuclear Information System (INIS)

    Yang Bingxing; Shi Jiahua; Pramoda, K P; Goh, Suat Hong

    2007-01-01

    Phenoxy (poly(hydroxyether of bisphenol-A), also known as poly(bisphenol-A-co-epichlorohydrin)) was grafted onto multiwalled carbon nanotubes (MWNTs) by a reactive blending process. Reactions between terminal glycidyl groups of phenoxy and carboxylic acid groups of acidified MWNTs resulted in the grafting of phenoxy chains onto MWNTs. The mechanical properties of composites of poly(ethylene oxide) (PEO) and phenoxy-grafted MWNTs were studied. The miscibility between PEO and phenoxy enabled the good dispersion of nanotubes in the PEO matrix as evidenced by polarized optical microscopy and transmission electron microscopy. The spherulite size of PEO progressively decreased with increasing amount of phenoxy-grafted MWNTs added. At an optimal MWNT content of 1.5 wt%, the addition of phenoxy-grafted MWNTs led to increases of storage modulus, Young's modulus, yield stress, tensile strength, ultimate strain, and toughness of PEO by 113, 228, 166, 442, 1240, and 4080%, respectively. Such simultaneous increases in stiffness, strength, ductility and toughness of a polymer by an additive are rather uncommon

  18. Derivation of endogenous equivalent values to support risk assessment and risk management decisions for an endogenous carcinogen: Ethylene oxide.

    Science.gov (United States)

    Kirman, C R; Hays, S M

    2017-12-01

    An approach is presented for ethylene oxide (EO) to derive endogenous equivalent (EE) values, which are endogenous levels normally found within the body expressed in terms of exogenous exposures. EE values can be used to support risk assessment and risk management decisions for chemicals such as EO that have both endogenous and exogenous exposure pathways. EE values were derived using a meta-analysis of data from the published literature characterizing the distribution for an EO biomarker of exposure, hemoglobin N-(2-hydroxyethyl)-valine (HEV), in unexposed populations. These levels are compared to the those reported in exposed populations (smokers, workers). Correlation between the biomarker of exposure and external exposures of EO were applied to this distribution to determine corresponding EE values, which range from 0.13 to 6.9 ppb for EO in air. These values are orders of magnitude higher than risk-based concentration values derived for EO using default methods, and are provided as a pragmatic, data-driven alternative approach to managing the potential risks from exogenous exposures to EO. Copyright © 2017 Elsevier Inc. All rights reserved.

  19. Preparation of protein- and cell-resistant surfaces by hyperthermal hydrogen induced cross-linking of poly(ethylene oxide).

    Science.gov (United States)

    Bonduelle, Colin V; Lau, Woon M; Gillies, Elizabeth R

    2011-05-01

    The functionalization of surfaces with poly(ethylene oxide) (PEO) is an effective means of imparting resistance to the adsorption of proteins and the attachment and growth of cells, properties that are critical for many biomedical applications. In this work, a new hyperthermal hydrogen induced cross-linking (HHIC) method was explored as a simple one-step approach for attaching PEO to surfaces through the selective cleavage of C-H bonds and subsequent cross-linking of the resulting carbon radicals. In order to study the effects of the process on the polymer, PEO-coated silicon wafers were prepared and the effects of different treatment times were investigated. Subsequently, using an optimized treatment time and a modified butyl polymer with increased affinity for PEO, the technique was applied to butyl rubber surfaces. All of the treated surfaces exhibited significantly reduced protein adsorption and cell growth relative to control surfaces and compared favorably with surfaces that were functionalized with PEO using conventional chemical methods. Thus HHIC is a simple and effective means of attaching PEO to non-functional polymer surfaces.

  20. Structure–Activity Relationship To Screen Ni–Bisphosphine Complexes for the Oxidative Coupling of CO2 and Ethylene

    KAUST Repository

    Al-Ghamdi, Miasser

    2017-03-07

    Density functional theory calculations have been used to investigate competition between inner- and outer-sphere reaction pathways in the oxidative coupling of CO2 and ethylene for a set of 12 Ni–bisphosphine complexes, in order to build a QSAR approach correlating catalyst structure to calculated energy barriers for CO2 activation. The ligands were selected to explore different substituents on the P atoms (cyclohexyl, phenyl, and tert-butyl) and different lengths of the tether connecting the P atoms, −(CH2)n– with n = 1–3. As expected, the conclusion is that the inner-sphere reaction pathway is favored with unhindered ligands, while the outer-sphere reaction pathway is favored with hindered ligands. To find a possible correlation with molecular descriptors, we started using the buried volume as a steric descriptor. A reasonable correlation could be found for the energy barrier along the inner-sphere pathway, while scarce correlation was found for the energy barrier along the outer-sphere pathway, indicating that the steric bulkiness of the ligand disfavors approach of CO2 to the metal center. Much stronger correlation between the ligand structure and the energy barrier along the inner-sphere pathway was achieved when the steric descriptor was augmented by an electronic descriptor, consisting of the partial charge on the Ni atom. The much better correlation suggests that bisphosphine ligands have a non-negligible electronic impact on the catalyst performance.

  1. Adsorption energies of poly(ethylene oxide)-based surfactants and nanoparticles on an air-water surface.

    Science.gov (United States)

    Zell, Zachary A; Isa, Lucio; Ilg, Patrick; Leal, L Gary; Squires, Todd M

    2014-01-14

    The self-assembly of polymer-based surfactants and nanoparticles on fluid-fluid interfaces is central to many applications, including dispersion stabilization, creation of novel 2D materials, and surface patterning. Very often these processes involve compressing interfacial monolayers of particles or polymers to obtain a desired material microstructure. At high surface pressures, however, even highly interfacially active objects can desorb from the interface. Methods of directly measuring the energy which keeps the polymer or particles bound to the interface (adsorption/desorption energies) are therefore of high interest for these processes. Moreover, though a geometric description linking adsorption energy and wetting properties through the definition of a contact angle can be established for rigid nano- or microparticles, such a description breaks down for deformable or aggregating objects. Here, we demonstrate a technique to quantify desorption energies directly, by comparing surface pressure-density compression measurements using a Wilhelmy plate and a custom-microfabricated deflection tensiometer. We focus on poly(ethylene oxide)-based polymers and nanoparticles. For PEO-based homo- and copolymers, the adsorption energy of PEO chains scales linearly with molecular weight and can be tuned by changing the subphase composition. Moreover, the desorption surface pressure of PEO-stabilized nanoparticles corresponds to the saturation surface pressure for spontaneously adsorbed monolayers, yielding trapping energies of ∼10(3) k(B)T.

  2. Binding of ethylene oxide in spermiogenic germ cell stages of the mouse after low-level inhalation exposure

    International Nuclear Information System (INIS)

    Sega, G.A.; Owens, J.G.

    1987-01-01

    Mice received inhalation exposures of 3 H-labeled ethylene oxide (EtO) gas at levels from 0.65 to 3.2 parts per million-hours (ppm-hr), which are below the exposure limits currently allowed for humans. Subsequently, spermatozoa were recovered from the reproductive tracts of the animals over a two-week period and assayed for the amount of bound EtO. A strong increase in the level of EtO binding occurred in late spermatid stages; these stages are also genetically sensitive to the action of EtO. Alkylation of the DNA within the sperm accounted for a very small fraction of the total sperm head alkylation, averaging about 20 DNA alkylations per sperm per ppm-hr of exposure over the two-week period. However, alkylation of protamine, a protein unique to sperm cells, was found to be correlated with total sperm head alkylation and accounted for nearly all of the EtO binding. Protamine alkylation appears to be a significant cause of EtO-induced genetic damage in spermiogenic cells of the mammal

  3. Development of CO2 Selective Poly(Ethylene Oxide-Based Membranes: From Laboratory to Pilot Plant Scale

    Directory of Open Access Journals (Sweden)

    Torsten Brinkmann

    2017-08-01

    Full Text Available Membrane gas separation is one of the most promising technologies for the separation of carbon dioxide (CO2 from various gas streams. One application of this technology is the treatment of flue gases from combustion processes for the purpose of carbon capture and storage. For this application, poly(ethylene oxide-containing block copolymers such as Pebax® or PolyActive™ polymer are well suited. The thin-film composite membrane that is considered in this overview employs PolyActive™ polymer as a selective layer material. The membrane shows excellent CO2 permeances of up to 4 m3(STP·(m2·h·bar−1 (1 bar = 105 Pa at a carbon dioxide/nitrogen (CO2/N2 selectivity exceeding 55 at ambient temperature. The membrane can be manufactured reproducibly on a pilot scale and mounted into flat-sheet membrane modules of different designs. The operating performance of these modules can be accurately predicted by specifically developed simulation tools, which employ single-gas permeation data as the only experimental input. The performance of membranes and modules was investigated in different pilot plant studies, in which flue gas and biogas were used as the feed gas streams. The investigated processes showed a stable separation performance, indicating the applicability of PolyActive™ polymer as a membrane material for industrial-scale gas processing.

  4. Self-assembling of poly(ε-caprolactone)-b-poly(ethylene oxide) diblock copolymers in aqueous solution and at the silica-water interface

    International Nuclear Information System (INIS)

    Leyh, B.; Vangeyte, P.; Heinrich, M.; Auvray, L.; De Clercq, C.; Jerome, R.

    2004-01-01

    Small-angle neutron scattering is used to investigate the self-assembling behaviour of poly(ε-caprolactone)-b-poly(ethylene oxide) diblock copolymers with various block lengths (i) in aqueous solution, (ii) in aqueous solution with the addition of sodium dodecyl sulphate (SDS) and (iii) at the silica-water interface. Micelles are observed under our experimental conditions due to the very small critical micellar concentration of these copolymers (0.01 g/l). The poly(ε-caprolactone) core is surrounded by a poly(ethylene oxide) corona. The micellar form factors have been measured at low copolymer concentrations (0.2 wt%) under selected contrast matching conditions. The data have been fitted to various analytical models to extract the micellar core and corona sizes. SDS is shown to induce partial micelle disruption together with an increase of the poly(ethylene oxide) corona extension from 25% (without SDS) to 70% (with SDS) of a completely extended PEO 114 chain. Our data at the silica-water interface are compatible with the adsorption of micelles

  5. Citric Acid-Modified Fenton's Reaction for the Oxidation of Chlorinated Ethylenes in Soil Solution Systems

    Energy Technology Data Exchange (ETDEWEB)

    Seol, Yongkoo; Javandel, Iraj

    2008-03-15

    Fenton's reagent, a solution of hydrogen peroxide and ferrous iron catalyst, is used for an in-situ chemical oxidation of organic contaminants. Sulfuric acid is commonly used to create an acidic condition needed for catalytic oxidation. Fenton's reaction often involves pressure buildup and precipitation of reaction products, which can cause safety hazards and diminish efficiency. We selected citric acid, a food-grade substance, as an acidifying agent to evaluate its efficiencies for organic contaminant removal in Fenton's reaction, and examined the impacts of using citric acid on the unwanted reaction products. A series of batch and column experiments were performed with varying H{sub 2}O{sub 2} concentrations to decompose selected chlorinated ethylenes. Either dissolved iron from soil or iron sulfate salt was added to provide the iron catalyst in the batch tests. Batch experiments revealed that both citric and sulfuric acid systems achieved over 90% contaminant removal rates, and the presence of iron catalyst was essential for effective decontamination. Batch tests with citric acid showed no signs of pressure accumulation and solid precipitations, however the results suggested that an excessive usage of H{sub 2}O{sub 2} relative to iron catalysts (Fe{sup 2+}/H{sub 2}O{sub 2} < 1/330) would result in lowering the efficiency of contaminant removal by iron chelations in the citric acid system. Column tests confirmed that citric acid could provide suitable acidic conditions to achieve higher than 55% contaminant removal rates.

  6. Phase behavior in blends of ethylene oxide-propylene oxide copolymer and poly(ether sulfone) studied by modulated-temperature DSC and NMR relaxometry.

    Science.gov (United States)

    Van Lokeren, Luk; Gotzen, Nicolaas-Alexander; Pieters, Ronny; Van Assche, Guy; Biesemans, Monique; Willem, Rudolph; Van Mele, Bruno

    2009-01-01

    The state diagram of a blend consisting of a copolymer containing ethylene oxide and propylene oxide, P(EO-ran-PO), and poly(ether sulfone), PES, is constructed by using modulated-temperature differential scanning calorimetry (MTDSC), T(2) NMR relaxometry, and light scattering. The apparent heat capacity signal in MTDSC is used for the characterization of polymer miscibility and morphology development. T(2) NMR relaxometry is used to detect the onset of phase separation, which is in good agreement with the onset of phase separation in the apparent heat capacity from MTDSC and the cloud-point temperature as determined from light scattering. The coexistence curve can be constructed from T(2) values at various temperatures by using a few blends with well-chosen compositions. These T(2) values also allow the detection of the boundary between the demixing zones with and without interference of partial vitrification and are in good agreement with stepwise quasi-isothermal MTDSC heat capacity measurements. Important interphases are detected in the heterogeneous P(EO-ran-PO)/PES blends.

  7. Side-chain degradation of ultrapure π-conjugated oligomers: implications for organic electronics

    NARCIS (Netherlands)

    Abbel, R.J.; Wolffs, M.; Bovee, R.A.A.; Dongen, van J.L.J.; Lou, X.W.; Henze, O.; Feast, W.J.; Meijer, E.W.; Schenning, A.P.H.J.

    2009-01-01

    The degrdn. of two defect-free pi-conjugated oligomers and the participation of their solubilizing side chains in the process are studied in unprecedented detail. The detected intermediate products reveal a mechanism of successive shortening of alkyl and oligo(ethylene glycol) substituents.

  8. The selective partitioning of the oligomers of polyethoxylated surfactant mixtures between interface and oil and water bulk phases.

    Science.gov (United States)

    Graciaa, Alain; Andérez, José; Bracho, Carlos; Lachaise, Jean; Salager, Jean-Louis; Tolosa, Laura; Ysambertt, Fredy

    2006-11-16

    Because their affinities for the oil and water phases vary considerably with the number of ethylene oxide units in their hydrophilic group, the ethoxylated nonionic species occurring in commercial products tend to behave in a non-collective way, with the low ethoxylation oligomers partitioning mostly in the oil phase. This results in a surfactant mixture at the interface which is more hydrophilic than the one which was introduced in the system in the first place. The pseudophase model is used to study the partitioning in Winsor III type systems, and to estimate the deviation of the interfacial mixture composition from the overall one. New results indicate that the selective partitioning into the oil phase increases when the oil phase becomes aromatic, when the total surfactant concentration decreases and when the water-to-oil ratio decreases.

  9. Zinc oxide and chromia as catalysts for the isomerization of butene, the hydrogenation of ethylene, and the isotopic exchange and allotropic conversion of hydrogen

    International Nuclear Information System (INIS)

    Conner, W.C. Jr.

    1973-01-01

    Hydrogenation of olefins has been studied over metals and metal oxides. Over metals the following observations generalize the characteristics of hydrogenation and isomerization. Metal hydrogenation catalysts are effective for H 2 -D 2 exchange (and para hydrogen conversion) under the same conditions as they effect olefin hydrogenation. This suggests that hydrogen ''activation'' involves formation of hydrogen atoms as a surface intermediate. Addition of deuterium to light ethylene leads to ethane products of the form C 2 H/sub 6-x/D/sub x/ (where 0 less than or equal to x less than or equal to 6). This is a result of the reversal of the alkyl (C 2 H 5 *) formation on the surface. Moreover, efficient isomerization of olefins require hydrogen as a co-catalyst. Both these observations suggest that alkyl formation and its reversal play a major role in hydrogenation and related reactions over metals. In this work it is found that zinc oxide catalyzes the deuteration of ethylene to dideuterioethane selectivity. Furthermore, the hydrogenation of ethylene using mixtures of hydrogen and deuterium indicate that hydrogenation occurs in such a manner as to reflect the molecular identity of the gas phase in the product ethane

  10. Titanate nanotubes for reinforcement of a poly(ethylene oxide)/chitosan polymer matrix

    Science.gov (United States)

    Porras, R.; Bavykin, D. V.; Zekonyte, J.; Walsh, F. C.; Wood, R. J.

    2016-05-01

    Soft polyethylene oxide (PEO)/chitosan mixtures, reinforced with hard titanate nanotubes (TiNTs) by co-precipitation from aqueous solution, have been used to produce compact coatings by the ‘drop-cast’ method, using water soluble PEO polymer and stable, aqueous colloidal solutions of TiNTs. The effects of the nanotube concentration and their length on the hardness and modulus of the prepared composite have been studied using nanoindentation and nanoscratch techniques. The uniformity of TiNT dispersion within the polymer matrix has been studied using transmission electron microscopy (TEM). A remarkable increase in hardness and reduced Young’s modulus of the composites, compared to pure polymer blends, has been observed at a TiNT concentration of 25 wt %. The short (up to 30 min) ultrasound treatment of aqueous solutions containing polymers and a colloidal TiNT mixture prior to drop casting has resulted in some improvements in both hardness and reduced Young’s modulus of dry composite films, probably due to a better dispersion of ceramic nanotubes within the matrix. However, further (more than 1 h) treatment of the mixture with ultrasound resulted in a deterioration of the mechanical properties of the composite accompanied by a shortening of the nanotubes, as observed by the TEM.

  11. PIPERIDINE OLIGOMERS AND COMBINATORIAL LIBRARIES THEREOF

    DEFF Research Database (Denmark)

    1999-01-01

    The present invention relates to piperidine oligomers, methods for the preparation of piperidine oligomers and compound libraries thereof, and the use of piperidine oligomers as drug substances. The present invention also relates to the use of combinatorial libraries of piperidine oligomers...... in libraries (arrays) of compounds especially suitable for screening purposes....

  12. Self-assembly in poly(dimethylsiloxane)-poly(ethylene oxide) block copolymer template directed synthesis of Linde type A zeolite.

    Science.gov (United States)

    Bonaccorsi, Lucio; Calandra, Pietro; Kiselev, Mikhail A; Amenitsch, Heinz; Proverbio, Edoardo; Lombardo, Domenico

    2013-06-11

    We describe the hydrothermal synthesis of zeolite Linde type A (LTA) submicrometer particles using a water-soluble amphiphilic block copolymer of poly(dimethylsiloxane)-b-poly(ethylene oxide) as a template. The formation and growth of the intermediate aggregates in the presence of the diblock copolymer have been monitored by small-angle X-ray scattering (SAXS) above the critical micellar concentration at a constant temperature of 45 °C. The early stage of the growth process was characterized by the incorporation of the zeolite LTA components into the surface of the block copolymer micellar aggregates with the formation of primary units of 4.8 nm with a core-shell morphology. During this period, restricted to an initial time of 1-3 h, the core-shell structure of the particles does not show significant changes, while a subsequent aggregation process among these primary units takes place. A shape transition of the SAXS profile at the late stage of the synthesis has been connected with an aggregation process among primary units that leads to the formation of large clusters with fractal characteristics. The formation of large supramolecular assemblies was finally verified by scanning electron microscopy, which evidenced the presence of submicrometer aggregates with size ranging between 100 and 300 nm, while X-ray diffraction confirmed the presence of crystalline zeolite LTA. The main finding of our results gives novel insight into the mechanism of formation of organic-inorganic mesoporous materials based on the use of a soft interacting nanotemplate as well as stimulates the investigation of alternative protocols for the synthesis of novel hybrid materials with new characteristics and properties.

  13. Nitric oxide mediates strigolactone signaling in auxin and ethylene-sensitive lateral root formation in sunflower seedlings.

    Science.gov (United States)

    Bharti, Niharika; Bhatla, Satish C

    2015-01-01

    Strigolactones (SLs) play significant role in shaping root architecture whereby auxin-SL crosstalk has been observed in SL-mediated responses of primary root elongation, lateral root formation and adventitious root (AR) initiation. Whereas GR24 (a synthetic strigolactone) inhibits LR and AR formation, the effect of SL biosynthesis inhibitor (fluridone) is just the opposite (root proliferation). Naphthylphthalamic acid (NPA) leads to LR proliferation but completely inhibits AR development. The diffusive distribution of PIN1 in the provascular cells in the differentiating zone of the roots in response to GR24, fluridone or NPA treatments further indicates the involvement of localized auxin accumulation in LR development responses. Inhibition of LR formation by GR24 treatment coincides with inhibition of ACC synthase activity. Profuse LR development by fluridone and NPA treatments correlates with enhanced [Ca(2+)]cyt in the apical region and differentiating zones of LR, indicating a critical role of [Ca(2+)] in LR development in response to the coordinated action of auxins, ethylene and SLs. Significant enhancement of carotenoid cleavage dioxygenase (CCD) activity (enzyme responsible for SL biosynthesis) in tissue homogenates in presence of cPTIO (NO scavenger) indicates the role of endogenous NO as a negative modulator of CCD activity. Differences in the spatial distribution of NO in the primary and lateral roots further highlight the involvement of NO in SL-modulated root morphogenesis in sunflower seedlings. Present work provides new report on the negative modulation of SL biosynthesis through modulation of CCD activity by endogenous nitric oxide during SL-modulated LR development.

  14. Development and validation of a protocol for field validation of passive dosimeters for ethylene oxide excursion limit monitoring

    Energy Technology Data Exchange (ETDEWEB)

    Puskar, M.A.; Szopinski, F.G.; Hecker, L.H. (Corporate Industrial Hygiene Laboratory, Abbott Laboratories, North Chicago, IL (USA))

    1991-04-01

    An exposure and analysis protocol is described for the field validation of passive dosimeters for ethylene oxide (EtO) excursion limit monitoring. The protocol calls for the use of a field exposure chamber with concurrent sampling using Tedlar air-sampling bags. The bags are analyzed immediately after sampling by gas chromatography with flame ionization detection (GC-FID). The chamber design allows all monitors to be exposed for the exact same time in the field. The sampling and analysis procedure not only determines the actual concentration of EtO present during the monitor's exposure but estimates if concentrations of EtO vary from point to point in the monitor array during the exposure. In chamber operation, the accuracy of the standard generator used to calibrate the GC-FID was independently verified in the field by the standard additions method. The sampling bias of the sampling train was determined to be -3.5% in the 2.4 ppm to 14.3 ppm concentration range. To estimate the stability of collected EtO samples in Tedlar bags, the rate of EtO loss in the bags was determined to be 0.011 ppm/hr at 2.57 ppm and 0.066 ppm/hr at 8.07 ppm. Sampling bias of the passive methods by additional EtO exposure of the monitors in the closed chamber after sampling and during purging was determined to be +1.5%. The Tedlar bag sampling method with subsequent GC-FID determination demonstrated a coefficient of variation of 1.8% at 2.43 ppm.

  15. Lactosylated poly(ethylene oxide)-poly(propylene oxide) block copolymers for potential active targeting: synthesis and physicochemical and self-aggregation characterization

    Energy Technology Data Exchange (ETDEWEB)

    Cuestas, Maria L.; Glisoni, Romina J. [University of Buenos Aires, Group of Biomaterials and Nanotechnology for Improved Medicines (BIONIMED), Department of Pharmaceutical Technology, Faculty of Pharmacy and Biochemistry (Argentina); Mathet, Veronica L. [National Science Research Council (CONICET) (Argentina); Sosnik, Alejandro, E-mail: alesosnik@gmail.com [University of Buenos Aires, The Group of Biomaterials and Nanotechnology for Improved Medicines (BIONIMED), Department of Pharmaceutical Technology, Faculty of Pharmacy and Biochemistry (Argentina)

    2013-01-15

    Aiming to develop polymeric self-assembly nanocarriers with potential applications in active drug targeting to the liver, linear and branched poly(ethylene oxide)-poly(propylene oxide) amphiphiles were conjugated to lactobionic acid (LA), a disaccharide of galactose and gluconic acid, by the conventional Steglich esterification reaction. The conjugation was confirmed by ATR/FT-IR, {sup 1}H-NMR, and {sup 13}C-NMR spectroscopy. Elemental analysis and MALDI-TOF mass spectrometry were employed to elucidate the conjugation extent and the final molecular weight, respectively. The critical micellar concentration (CMC), the size and size distribution and zeta potential of the pristine and modified polymeric micelles under different conditions of pH and temperature were characterized by dynamic light scattering (DLS). Conjugation with LA favored the micellization process, leading to a decrease of the CMC with respect to the pristine counterpart, this phenomenon being independent of the pH and the temperature. At 37 Degree-Sign C, micelles made of pristine copolymers showed a monomodal size distribution between 12.8 and 24.4 nm. Conversely, LA-conjugated micelles showed a bimodal size pattern that comprised a main fraction of relatively small size (11.6-22.2 nm) and a second one with remarkably larger sizes of up to 941.4 nm. The former corresponded to single micelles, while the latter would indicate a secondary aggregation phenomenon. The spherical morphology of LA-micelles was visualized by transmission electron microscopy (TEM). Finally, to assess the ability of the LA-conjugated micelles to interact with lectin-like receptors, samples were incubated with concanavalin A at 37 Degree-Sign C and the size and size distribution were monitored by DLS. Findings indicated that regardless of the relatively weak affinity of this vegetal lectin for galactose, micelles underwent agglutination probably through the interaction of a secondary site in the lectin with the gluconic acid

  16. Preparation and Properties of Poly (vinylidene fluoride)/poly(dimethylsiloxane) graft (poly(propylene oxide)-block-poly(ethylene oxide)) blend porous separators and corresponding electrolytes

    International Nuclear Information System (INIS)

    Li, Hao; Zhang, Hong; Liang, Zhi-Ying; Chen, Yue-Ming; Zhu, Bao-Ku; Zhu, Li-Ping

    2014-01-01

    Highlights: •This work aims exploring microporous PVDF separators for lithium ion batteries. •Comb structure polymer PDMS-g-(PPO-PEO) was used in PVDF blend separators. •The influence of polyether side chains on interfacial resistance was studied. -- Abstract: This work aims exploring the high performance porous separators that can be activated into gel electrolyte membranes for lithium ion batteries. A comb-like copolymer poly (dimethylsiloxane) graft poly (propylene oxide)-block-poly (ethylene oxide) (PDMS-g-(PPO-PEO)) was synthesized and blended with poly (vinylidene fluoride) (PVDF) to fabricate porous separators via a typical phase inversion process, and then the separators absorbed liquid electrolyte solution and formed into polymer electrolyte membranes. By measuring the composition, morphology and ion conductivity etc, the influence of PDMS-g-(PPO-PEO) on structure and properties of blend separators were discussed. Compared with pure PVDF separator with comparable porous structure, the adoption of PDMS-g-(PPO-PEO) decreased the crystallinity and increased the liquid electrolyte uptake and stability effectively. It was also found that the electrode/electrolyte interfacial resistance could be reduced greatly. The resulting electrolyte membrane using separator with PVDF/PDMS-g-(PPO-PEO) mass ratio in 8/2 exhibited highest ionic conductivity in 4.5 × 10 −3 S/cm at room temperature, while the electrochemical stability was up to 4.7 V (vs. Li/Li + ). Coin cells assembled with such separators also exhibited stable cycle performance and improved rate capabilities, especially when discharge rate higher than 0.5 C

  17. Effect of rare earth cations on activity of type Y zeolites in ethylene transformations

    International Nuclear Information System (INIS)

    Amezhnova, G.N.; Zhavoronkov, M.N.; Dorogochinskij, A.Z.; Proskurin, A.L.; Shmailova, V.I.

    1984-01-01

    The ethylene transformations on type Y rare earth zeolites with high degrees of sodium exchange are studied. It is shown that rare earth cations increase zeolites activity with growth of electronoacceptor capacity. The ethylene oligomerization occurs on polyvalent cations while subsequent oligomer transformations - on hydroxyl groups of zeolites

  18. Star-shaped tetrathiafulvalene oligomers towards the construction of conducting supramolecular assembly.

    Science.gov (United States)

    Iyoda, Masahiko; Hasegawa, Masashi

    2015-01-01

    The construction of redox-active supramolecular assemblies based on star-shaped and radially expanded tetrathiafulvalene (TTF) oligomers with divergent and extended conjugation is summarized. Star-shaped TTF oligomers easily self-aggregate with a nanophase separation to produce supramolecular structures, and their TTF units stack face-to-face to form columnar structures using the fastener effect. Based on redox-active self-organizing supramolecular structures, conducting nanoobjects are constructed by doping of TTF oligomers with oxidants after the formation of such nanostructures. Although radical cations derived from TTF oligomers strongly interact in solution to produce a mixed-valence dimer and π-dimer, it seems to be difficult to produce nanoobjects of radical cations different from those of neutral TTF oligomers. In some cases, however, radical cations form nanostructured fibers and rods by controlling the supramolecular assembly, oxidation states, and counter anions employed.

  19. Effect of CO{sub 2}-admixture on the catalytic performance of Ni-Nb-M-O catalysts in oxidative dehydrogenation of ethane to ethylene

    Energy Technology Data Exchange (ETDEWEB)

    Qiao, A.; Kalevaru, V.N.; Martin, A. [Rostock Univ. (Germany). Leibniz-Institut fuer Katalyse e.V.; Hari Kumar, A. Sri; Lingaiah, N.; Prasad, P.S. Sai [Indian Institute of Chemical Technology, Hyderabad (India). Inorganic and Physical Chemistry Div.

    2012-07-01

    In this work, we report the synthesis, characterization and application of Ni-Nb-M-O catalysts with different promoters (M = Cr, Mo, W) for the oxidative dehydrogenation (ODH) of ethane to ethylene. Ni:Nb:M ratio was kept at 1:0.176:0.1 (atomic ratio). The catalysts were calcined at 450 C/5h/air. Catalytic tests were carried out in a fixed bed quartz reactor in the temperature range from 300 to 450 C, with a fixed W/F (1.02 g/cm{sup 3} . s{sup -1}) but with changing mole ratios of C{sub 2}H{sub 6}:O{sub 2}:CO{sub 2}:N{sub 2} (1:0-1.4:1.4-0:2). The product analysis was made off-line using GC equipped with FID. It is evident that the CO{sub 2}-admixture to the reactant feed caused a slight decrease in the conversion of ethane but considerably improved the selectivity of ethylene. Among the three promoters of the same group applied, Cr exhibited superior performance compared to other two. This means increase in d-character of transition metal (i.e. from 3d to 5d) has shown an adverse effect on the conversion of ethane and selectivity of ethylene. (orig.)

  20. Fourier transform infrared studies of reduction of nitric oxide by ethylene over V[sub 2]O[sub 5] layered on ZrO[sub 2

    Energy Technology Data Exchange (ETDEWEB)

    Ohno, Takashi; Hatayama, Fumikazu (School of Allied Medical Sciences, Kobe University, Kobe (Japan)); Toda, Yoshio (Department of Industrial Chemistry, Osaka Prefectural Technical College, Osaka (Japan)); Konishi, Shoichiro; Miyata, Hisashi (Department of Applied Chemistry, University of Osaka Prefecture, Osaka (Japan))

    1994-12-31

    The reduction mechanism of nitric oxide by ethylene in the presence or absence of oxygen on mono- and multi-layer V[sub 2]O[sub 5]/ZrO[sub 2] and the structures of the catalysts under reaction conditions have been studied by Fourier transform infrared spectroscopy as well as by analysis of the reaction products. For the reaction of a mixture of NO+C[sub 2]H[sub 4], only carboxylate species were observed at higher temperatures, although at lower temperatures nitrate species were formed. No bands due to a complex of NO+C[sub 2]H[sub 4] were observed. From the results, it is proposed that ethylene is oxidized by the catalyst to form carbon dioxide via carbonyl and carboxylate species and nitric oxide reoxidizes the catalyst to form nitrogen. The quantitative analysis of the V=O band in the region of 1100-900 cm[sup -1] by band shape analysis indicates that only the surface V=O species in the top layer of the catalyst interacts with the adsorbed species

  1. Release of Bacteriocins from Nanofibers Prepared with Combinations of Poly(D,L-lactide (PDLLA and Poly(Ethylene Oxide (PEO

    Directory of Open Access Journals (Sweden)

    Leon Dicks

    2011-03-01

    Full Text Available Plantaricin 423, produced by Lactobacillus plantarum, and bacteriocin ST4SA produced by Enterococcus mundtii, were electrospun into nanofibers prepared from different combinations of poly(D,L-lactide (PDLLA and poly(ethylene oxide (PEO dissolved in N,N-dimethylformamide (DMF. Both peptides were released from the nanofibers with a high initial burst and retained 88% of their original antimicrobial activity at 37 °C. Nanofibers have the potential to serve as carrier matrix for bacteriocins and open a new field in developing controlled antimicrobial delivery systems for various applications.

  2. Poly (ethylene oxide)-block-poly (n-butyl acrylate)-blockpoly (acrylic acid) triblock terpolymers with highly asymmetric hydrophilic blocks: synthesis and aqueous solution properties

    OpenAIRE

    Petrov, P. (Petar); Yoncheva, K. (Krassimira); Mokreva, P. (Pavlina); Konstantinov, S. (Spiro); Irache, J.M. (Juan Manuel); Müller, A.H.E. (Axel H.E.)

    2013-01-01

    The synthesis and aggregation behaviour in aqueous media of novel amphiphilic poly(ethylene oxide)- block-poly(n-butyl acrylate)-block-poly(acrylic acid) (PEO–PnBA–PAA) triblock terpolymers were studied. Terpolymers composed of two highly asymmetric hydrophilic PEO (113 monomer units) and PAA (10–17 units) blocks, and a longer soft hydrophobic PnBA block (163 or 223 units) were synthesized by atom transfer radical polymerisation (ATRP) of n-butyl acrylate and tert-butyl acrylate ...

  3. Cytotoxicity of Paclitaxel in biodegradable self-assembled core-shell poly(lactide-co-glycolide ethylene oxide fumarate) nanoparticles.

    Science.gov (United States)

    He, Xuezhong; Ma, Junyu; Mercado, Angel E; Xu, Weijie; Jabbari, Esmaiel

    2008-07-01

    Biodegradable core-shell polymeric nanoparticles (NPs), with a hydrophobic core and hydrophilic shell, are developed for surfactant-free encapsulation and delivery of Paclitaxel to tumor cells. Poly (lactide-co-glycolide fumarate) (PLGF) and Poly (lactide-fumarate) (PLAF) were synthesized by condensation polymerization of ultra-low molecular weight poly(L: -lactide-co-glycolide) (ULMW PLGA) with fumaryl chloride (FuCl). Similarly, poly(lactide-co-ethylene oxide fumarate) (PLEOF) macromer was synthesized by reacting ultra-low molecular weight poly(L: -lactide) (ULMW PLA) and PEG with FuCl. The blend PLGF/PLEOF and PLAF/PLEOF macromers were self-assembled into NPs by dialysis. The NPs were characterized with respect to particle size distribution, morphology, and loading efficiency. The physical state and miscibility of Paclitaxel in NPs were characterized by differential scanning calorimetry. Tumor cell uptake and cytotoxicity of Paclitaxel loaded NPs were measured by incubation with HCT116 human colon carcinoma cells. The distribution of NPs in vivo was assessed with Apc(Min/+)mouse using infrared imaging. PLEOF macromer, due to its amphiphilic nature, acted as a surface active agent in the process of self-assembly which produced core-shell NPs with PLGF/PLAF and PLEOF macromers as the core and shell, respectively. The encapsulation efficiency ranged from 70 to 56% and it was independent of the macromer but decreased with increasing concentration of Paclitaxel. Most of the PLGF and PLAF NPs degraded in 15 and 28 days, respectively, which demonstrated that the release was dominated by hydrolytic degradation and erosion of the matrix. As the concentration of Paclitaxel was increased from 0 to 10, and 40 mug/ml, the viability of HCT116 cells incubated with free Paclitaxel decreased from 100 to 65 and 40%, respectively, while those encapsulated in PLGF/PLEOF NPs decreased from 93 to 54 and 28%. Groups with Paclitaxel loaded NPs had higher cytotoxicity compared to

  4. Determination of oligomers in virgin and recycled polyethylene terephthalate (PET) samples by UPLC-MS-QTOF.

    Science.gov (United States)

    Ubeda, Sara; Aznar, Margarita; Nerín, Cristina

    2018-03-01

    An oligomer is a molecule that consists of a few monomer units. It can be formed during polymer manufacturing and also due to polymer degradation processes or even during use conditions. Since oligomers are not included in chemical databases, their identification is a complex process. In this work, the oligomers present in 20 different PET pellet samples have been determined. Two different sample treatment procedures, solvent extraction and total dissolution, were applied in order to select the most efficient one. The analyses were carried out by UPLC-MS-QTOF. The use of high resolution mass spectrometry allowed the structural elucidation of these compounds and their correct identification. The main oligomers identified were cyclic as well as lineal from the first, second, and third series. All of them were composed of terephthalic acid (TPA), diethylene glycol (DEG), and ethylene glycol (EG). Quantitative values were very different in both procedures. In total dissolution of PET samples, the concentration of oligomers was always, at least, 10 times higher than in solvent extraction; some of the compounds were only detected when total dissolution was used. Results showed that the oligomers with the highest concentration values were dimers and trimers, cyclic, as well as lineal, from the first and second series. The oligomer with the maximum concentration value was TPA 2 -EG-DEG that was found in all the samples in a concentration range from 2493 to 19,290 ng/g PET. No differences between virgin and recycled PET were found. Migration experiments were performed in two PET bottles, and results showed the transference of most of these oligomers to a fat food simulant (ethanol 95%). Graphical abstract Graphical abstract of the two procedures developd and optimized for identifying oligomers in PET pellets and in migration form PET bottles.

  5. Nanostructures and surface hydrophobicity of self-assembled thermosets involving epoxy resin and poly(2,2,2-trifluoroethyl acrylate)-block-poly(ethylene oxide) amphiphilic diblock copolymer.

    Science.gov (United States)

    Yi, Fangping; Zheng, Sixun; Liu, Tianxi

    2009-02-19

    Poly(2,2,2-trifluoroethyl acrylate)-block-poly(ethylene oxide) (PTFEA-b-PEO) amphiphilic diblock copolymer was synthesized via the reversible addition-fragmentation transfer polymerization of 2,2,2-triffluroethyl acrylate with dithiobenzoyl-terminated poly(ethylene oxide) as a chain-transfer agent. The amphiphilic diblock copolymer was incorporated into epoxy resin to prepare the nanostructured epoxy thermosets. The nanostructures were investigated by means of atomic force microscopy, small-angle X-ray scattering, and dynamic mechanical analysis. In terms of the miscibility of the subchains of the block copolymer with epoxy after and before curing reaction, it is judged that the formation of the nanostructures follows the mechanism of self-assembly. The static contact angle measurements indicate that the nanostructured thermosets containing PTFEA-b-PEO diblock copolymer displayed a significant enhancement in surface hydrophobicity as well as a reduction in surface free energy. The improvement in surface properties was ascribed to the enrichment of the fluorine-containing subchain (i.e., PTFEA block) of the amphiphilic diblock copolymer on the surface of the nanostructured thermosets, which was evidenced by surface atomic force microscopy and energy-dispersive X-ray spectroscopy.

  6. Alteration in Oxidative/nitrosative imbalance, histochemical expression of osteopontin and antiurolithiatic efficacy of Xanthium strumarium (L.) in ethylene glycol induced urolithiasis.

    Science.gov (United States)

    Panigrahi, Padma Nibash; Dey, Sahadeb; Sahoo, Monalisa; Choudhary, Shyam Sundar; Mahajan, Sumit

    2016-12-01

    Xanthium strumarium has traditionally been used in the treatment of urolitiasis especially by the rural people in India, but its antiurolithiatic efficacy was not explored scientifically till now. Therefore, the present study was designed to validate the ethnic practice scientifically, and explore the possible antiurolithiatic effect to rationalize its medicinal use. Urolitiasis was induced in hyperoxaluric rat model by giving 0.75% ethylene glycol (EG) for 28days along with 1% ammonium chloride (AC) for first 14days. Antiurolithiatic effect of aqueous-ethanol extract of Xanthium strumarium bur (xanthium) was evaluated based on urine and serum biochemistry, oxidative/nitrosative stress indices, histopathology, kidney calcium and calcium oxalate content and immunohistochemical expression of matrix glycoprotein, osteopontin (OPN). Administration of EG and AC resulted in hyperoxaluria, crystalluria, hypocalciuria, polyurea, raised serum urea, creatinine, erythrocytic lipid peroxidise and nitric oxide, kidney calcium content as well as crystal deposition in kidney section in lithiatic group rats. However, xanthium treatment significantly restored the impairment in above kidney function test as that of standard treatment, cystone. The up-regulation of OPN was also significantly decreased after xanthium treatment. The present findings demonstrate the curative efficacy of xanthium in ethylene glycol induced urolithiasis, possibly mediated through inhibition of various pathways involved in renal calcium oxalate formation, antioxidant property and down regulation of matrix glycoprotein, OPN. Therefore, future studies may be established to evaluate its efficacy and safety for clinical use. Copyright © 2016 Elsevier Masson SAS. All rights reserved.

  7. A directional entrapment modification on the polyethylene surface by the amphiphilic modifier of stearyl-alcohol poly(ethylene oxide) ether

    Science.gov (United States)

    Lu, Qiang; Chen, Yi; Huang, Juexin; Huang, Jian; Wang, Xiaolin; Yao, Jiaying

    2018-05-01

    A novel entrapment modification method involving directional implantation of the amphiphilic modifier of stearyl-alcohol poly(ethylene oxide) ether (AEO) into the high-density polyethylene (HDPE) surface is proposed. This modification technique allows the AEO modifier to be able to spontaneously attain and subsequently penetrate into the swollen HDPE surface with its hydrophobic stearyl segment, while its hydrophilic poly(ethylene oxide) (PEO) segment spontaneously points to water. The AEO modifier with a HLB number below 8.7 was proved appropriate for the directional entrapment, Nevertheless, AEOs with larger HLB numbers were also effective modifiers in the presence of salt additives. In addition, a larger and hydrophobic micelle, induced respectively by the AEO concentration above 1.3 × 10-2 mol/L and the entrapping temperature above the cloud point of AEO, could lead to a sharp contact angle decline of the modified surface. Finally, a hydrophilic HDPE surface with the modifier coverage of 38.9% was reached by the directional entrapment method, which is far larger than that of 19.2% by the traditional entrapment method.

  8. Biocompatibility Assessment of Poly(lactic acid Films after Sterilization with Ethylene Oxide in Histological Study In Vivo with Wistar Rats and Cellular Adhesion of Fibroblasts In Vitro

    Directory of Open Access Journals (Sweden)

    Michele Savaris

    2017-01-01

    Full Text Available Biomaterials must meet certain fundamental requirements for their usage in living beings, such as biocompatibility, bifunctionality, and sterilizability, without having chemical and structural changes. The biocompatibility of poly(lactic acid (PLA films, shaped by compression, was evaluated after sterilization by ethylene oxide by a histological in vivo test with Wistar rats and cytotoxicity in cell adhesion in vitro. The cytotoxicity test was performed by the reduction of tetrazolium salt (MTT. Thermal and chemical changes in PLA films concerning the proposed sterilization process and characteristics were not observed to evidence polymer degradation due to sterilization. The analysis of the cytotoxicity by the MTT method has shown that the sterilized PLA films are not cytotoxic. The adhesion and proliferation of fibroblasts on PLA films were homogeneously distributed over the evaluation period, showing an elongated appearance with unnumbered cytoplasmic extensions and cell-cell interactions. By examining the biocompatibility in a histological study, a mild tissue inflammation was observed with the presence of fibrosis in the samples that had been exposed for 21 days in the rats’ bodies. PLA films sterilized with ethylene oxide did not exhibit cell adhesion in vitro and toxicity to the surrounding tissue in vivo and they may be used in future in vivo testing, according to histological findings in Wistar rats in the present study.

  9. Comparative effect of ethylene oxide and gamma irradiation on the chemical sensory and microbial quality of ginger, cinnamon, fennel and fenugreek

    International Nuclear Information System (INIS)

    Toofanian, F.; Stegeman

    1986-01-01

    The effect of gamma irradiation and ethylene oxide fumigation on the microbiological and sensory properties of ground cinnamon, ginger, fennel and fenugreek, and on the volatile oil content of ground cinnamon, ginger and fennel was investigated. Ground ginger, cinnamon, fennel and fenugreek were obtained from a Dutch trade company. Ginger originated from China, cinnamon was produced in Indonesia and fennel and fenugreek were produced in India. The samples were ground by the trade companies and divided in three parts. One part was fumigated by the trade companies at ambient temperatures during eight hours with ethylene oxide (EO) at a concentration of 1500/m 3 . The second part was gamma irradiated at room temperature in aluminium/polyethylene bags at the 40 KCi cobalt-60 research source of the pilot plant for food irradiation in Wageningen. The untreated, fumigated and irradiated samples were stored in gas-impermeable packages. It was found that for cinnamon and ginger a 6 KGy dose, for fennel, 6-10 KGy and for fenugreek 6-8 KGy dose were equal in microbial effects to the commercial established fumigation process. No significant change in the volatile oil content of the fumigated or irradiated cinnamon and fennel has been observed. Irradiation of ginger with a dose of 5 KGy resulted in a slight decrease of 14% while fumigated ginger showed no significant loss in volatile oil content. Between the untreated irradiated or fumigated spices no major differences in sensory properties were found

  10. Role of ethylene metabolism in Amaranthus retroflexus

    International Nuclear Information System (INIS)

    Raskin, I.; Beyer, E. Jr.

    1989-01-01

    14 C-Ethylene was metabolized by etiolated pigweed seedlings (Amaranthus retroflexus L.) in the manner similar to that observed in other plants. The hormone was oxidized to 14 CO 2 and incorporated into 14 -tissue components. Selected cyclic olefins with differing abilities to block ethylene action were used to determine if ethylene metabolism in pigweed is necessary for ethylene action. 2,5-Norbornadiene and 1,3-cyclohexadiene were effective inhibitors of ethylene action at 800 and 6400 μ1/1, respectively, in the gas phase, while 1,4-cyclohexadiene and cyclohexene were not. However, all four cyclic olefins inhibited the incorporation and conversion of 14 C-ethylene to 14 CO 2 by 95% with I 50 values below 100 μ1/1. The results indicate that total ethylene metabolism does not directly correlate with changes in ethylene action. Additionally, the fact that inhibition of ethylene metabolism by the cyclic olefins did not result in a corresponding increase in ethylene evolution, indicates that ethylene metabolism does not serve to significantly reduce endogenous ethylene levels

  11. Ionic liquids in a poly ethylene oxide cross-linked gel polymer as an electrolyte for electrical double layer capacitor

    Science.gov (United States)

    Chaudoy, V.; Tran Van, F.; Deschamps, M.; Ghamouss, F.

    2017-02-01

    In the present work, we developed a gel polymer electrolyte via the incorporation of a room temperature ionic liquid into a cross-linked polymer matrix. The cross-linked gel electrolyte was prepared using a free radical polymerization of methacrylate and dimethacrylate oligomers dissolved in 1-propyl-1-methylpyrrolidinium bis(fluorosulfonyl)imide. Combining the advantages of the ionic liquids and of conventional polymers, the cross-linked gel polymer electrolyte was used both as a separator and as an electrolyte for a leakage-free and non-flammable EDLC supercapacitor. The quasi-all solid-state supercapacitors showed rather good capacitance, power and energy densities by comparison to a liquid electrolyte-based EDLC.

  12. Intensification of ethylene glycol production process

    DEFF Research Database (Denmark)

    Wisutwattanaa, Apiwit; Frauzem, Rebecca; Suriyapraphadilok, Uthaiporn

    2017-01-01

    This study aims to generate an alternative design for ethylene glycol production process focusing on a reduction of operating cost and emissions. To achieve this, the phenomena-based method for process intensification was applied. 3 stages of process intensification were performed. First, the base......-case design was obtained, resulting in the production of ethylene glycol via two steps: ethylene oxidation synthesis followed by ethylene oxide hydration to produce ethylene glycol. Feasibility of the design was verified and the process was rigorously designed using a computer process simulation program...... solutions. As the result of intensification method, membrane separation was suggested and applied to the design. With the operation of the new equipment, the ethylene glycol production process was improved for 54.51 percent in terms of energy consumption....

  13. Electro-oxidation of ethanol and ethylene glycol on carbon-supported nano-Pt and -PtRu catalyst in acid solution

    International Nuclear Information System (INIS)

    Chatterjee, Moitrayee; Chatterjee, Abhik; Ghosh, Susanta; Basumallick, I.

    2009-01-01

    Present paper reports kinetics of electro-oxidation of ethanol (EtOH) and ethylene glycol (EG) onto Pt and PtRu nanocatalysts of different compositions in the temperature range of 298-318 K. These catalysts have been characterized by SEM, EDX, XRD, CV and amperometry. It has been observed that apparent activation energies for oxidation of EtOH and EG pass through a minimum at about 15-20 at.% of Ru in the PtRu alloy catalysts. Anodic peak current vs. composition curve also shows a maximum around this composition. The results have been explained by a geometric model, which proposes requirement of an ensemble of three Pt atoms with an adjacent Ru atom onto PtRu surface for an efficient electro-oxidation of EtOH or EG. This is further supported from statistical data analysis of probability of occurrence of such ensembles onto PtRu alloy surface. Present results also suggest that electro-oxidation of EG onto nano-PtRu catalyst surfaces follows a different path from that of EtOH at alloy composition less than 15 at.% of Ru.

  14. Electro-oxidation of ethanol and ethylene glycol on carbon-supported nano-Pt and -PtRu catalyst in acid solution

    Energy Technology Data Exchange (ETDEWEB)

    Chatterjee, Moitrayee; Chatterjee, Abhik; Ghosh, Susanta [Electrochemical Laboratory, Department of Chemistry, Visva-Bharati University, Santiniketan 731235 (India); Basumallick, I., E-mail: ibasumallick@yahoo.co.u [Electrochemical Laboratory, Department of Chemistry, Visva-Bharati University, Santiniketan 731235 (India)

    2009-12-01

    Present paper reports kinetics of electro-oxidation of ethanol (EtOH) and ethylene glycol (EG) onto Pt and PtRu nanocatalysts of different compositions in the temperature range of 298-318 K. These catalysts have been characterized by SEM, EDX, XRD, CV and amperometry. It has been observed that apparent activation energies for oxidation of EtOH and EG pass through a minimum at about 15-20 at.% of Ru in the PtRu alloy catalysts. Anodic peak current vs. composition curve also shows a maximum around this composition. The results have been explained by a geometric model, which proposes requirement of an ensemble of three Pt atoms with an adjacent Ru atom onto PtRu surface for an efficient electro-oxidation of EtOH or EG. This is further supported from statistical data analysis of probability of occurrence of such ensembles onto PtRu alloy surface. Present results also suggest that electro-oxidation of EG onto nano-PtRu catalyst surfaces follows a different path from that of EtOH at alloy composition less than 15 at.% of Ru.

  15. White organic light-emitting diodes based on electroplex from polyvinyl carbazole and carbazole oligomers blends

    International Nuclear Information System (INIS)

    Fei-Peng, Chen; Bin, Xu; Wen-Jing, Tian; Zu-Jin, Zhao; Ping, Lü; Chan, Im

    2010-01-01

    White organic light-emitting diodes with a blue emitting material fluorene-centred ethylene-liked carbazole oligomer (Cz6F) doped into polyvinyl carbazole (PVK) as the single light-emitting layer are reported. The optical properties of Cz6F, PVK, and PVK:Cz6F blends are studied. Single and double layer devices are fabricated by using PVK: Cz6F blends, and the device with the configuration of indium tin oxide (ITO)/PVK:Cz6F/tris(8-hydroxyquinolinate)aluminium (Alq 3 )/LiF/A1 exhibits white light emission with Commission Internationale de l'Éclairage chromaticity coordinates of (0.30, 0.33) and a brightness of 402 cd/m 2 . The investigation reveals that the white light is composed of a blue–green emission originating from the excimer of Cz6F molecules and a red emission from an electroplex from the PVK:Cz6F blend films

  16. White organic light-emitting diodes based on electroplex from polyvinyl carbazole and carbazole oligomers blends

    Science.gov (United States)

    Chen, Fei-Peng; Xu, Bin; Zhao, Zu-Jin; Tian, Wen-Jing; Lü, Ping; Im, Chan

    2010-03-01

    White organic light-emitting diodes with a blue emitting material fluorene-centred ethylene-liked carbazole oligomer (Cz6F) doped into polyvinyl carbazole (PVK) as the single light-emitting layer are reported. The optical properties of Cz6F, PVK, and PVK:Cz6F blends are studied. Single and double layer devices are fabricated by using PVK: Cz6F blends, and the device with the configuration of indium tin oxide (ITO)/PVK:Cz6F/tris(8-hydroxyquinolinate)aluminium (Alq3)/LiF/A1 exhibits white light emission with Commission Internationale de l'Éclairage chromaticity coordinates of (0.30, 0.33) and a brightness of 402 cd/m2. The investigation reveals that the white light is composed of a blue-green emission originating from the excimer of Cz6F molecules and a red emission from an electroplex from the PVK:Cz6F blend films.

  17. The inverse podant [Li3(NBut)3S)]+ stabilises a single ethylene oxide OCH=CH2 anion as a high- and low-temperature polymorph of [(thf)3Li3(OCH=CH2)(NBut)3S)].

    Science.gov (United States)

    Walfort, B; Pandey, S K; Stalke, D

    2001-09-07

    A single ethylene oxide anion derived from the ether cleavage reaction of thf with ButLi is stabilised by the inverse podant [Li3(NBut)3S)]+ to give a high- and a low-temperature polymorph with a considerable difference in conformation and packing.

  18. How the dispersion of magnesium oxide nanoparticles effects on the viscosity of water-ethylene glycol mixture: Experimental evaluation and correlation development

    Science.gov (United States)

    Afrand, Masoud; Abedini, Ehsan; Teimouri, Hamid

    2017-03-01

    In this paper, the effect of dispersion of magnesium oxide nanoparticles on viscosity of a mixture of water and ethylene glycol (50-50% vol.) was examined experimentally. Experiments were performed for various nanofluid samples at different temperatures and shear rates. Measurements revealed that the nanofluid samples with volume fractions of less than 1.5% had Newtonian behavior, while the sample with volume fraction of 3% showed non-Newtonian behavior. Results showed that the viscosity of nanofluids enhanced with increasing nanoparticles volume fraction and decreasing temperature. Results of sensitivity analysis revealed that the viscosity sensitivity of nanofluid samples to temperature at higher volume fractions is more than that of at lower volume fractions. Finally, because of the inability of the existing model to predict the viscosity of MgO/EG-water nanofluid, an experimental correlation has been proposed for predicting the viscosity of the nanofluid.

  19. Unusual kinetics of poly(ethylene glycol) oxidation with cerium(IV) ions in sulfuric acid medium and implications for copolymer synthesis.

    Science.gov (United States)

    Szymański, Jan K; Temprano-Coleto, Fernando; Pérez-Mercader, Juan

    2015-03-14

    The cerium(IV)-alcohol couple in an acidic medium is an example of a redox system capable of initiating free radical polymerization. When the alcohol has a polymeric nature, the outcome of such a process is a block copolymer, a member of a class of compounds possessing many useful properties. The most common polymer with a terminal -OH group is poly(ethylene glycol) (PEG); however, the detailed mechanism of its reaction with cerium(IV) remains underexplored. In this paper, we report our findings for this reaction based on spectrophotometric measurements and kinetic modeling. We find that both the reaction order and the net rate constant for the oxidation process depend strongly on the nature of the acidic medium used. In order to account for the experimental observations, we postulate that protonation of PEG decreases its affinity for some of the cerium(IV)-sulfate complexes formed in the system.

  20. Selective catalytic reduction of nitric oxide by ethylene over metal-modified ZSM-5- and {gamma}-Al{sub 2}O{sub 3}-catalysts

    Energy Technology Data Exchange (ETDEWEB)

    Eraenen, K; Kumar, N; Lindfors, L E [Aabo Akademi, Turku (Finland). Lab. of Industrial Chemistry

    1997-12-31

    Metal-modified ZSM-5 and {gamma}-Al{sub 2}O{sub 3} catalysts were tested in reduction of nitric oxide by ethylene. Different metals were introduced into the ZSM-5 catalyst by ion-exchange and by introduction of metals during the zeolite synthesis. To prepare bimetallic catalysts a combination of these methods was used. The {gamma}-Al{sub 2}O{sub 3} was impregnated with different metals by the incipient wetness technique and by adsorption. Activity measurements showed that the ZSM-5 based catalysts were more active than the {gamma}-Al{sub 2}O{sub 3} based catalysts. The highest conversion was obtained over a ZSM-5 catalyst prepared by introduction of Pd during synthesis of the zeolite and subsequently ion-exchanged with copper. (author)

  1. Selective catalytic reduction of nitric oxide by ethylene over metal-modified ZSM-5- and {gamma}-Al{sub 2}O{sub 3}-catalysts

    Energy Technology Data Exchange (ETDEWEB)

    Eraenen, K.; Kumar, N.; Lindfors, L.E. [Aabo Akademi, Turku (Finland). Lab. of Industrial Chemistry

    1996-12-31

    Metal-modified ZSM-5 and {gamma}-Al{sub 2}O{sub 3} catalysts were tested in reduction of nitric oxide by ethylene. Different metals were introduced into the ZSM-5 catalyst by ion-exchange and by introduction of metals during the zeolite synthesis. To prepare bimetallic catalysts a combination of these methods was used. The {gamma}-Al{sub 2}O{sub 3} was impregnated with different metals by the incipient wetness technique and by adsorption. Activity measurements showed that the ZSM-5 based catalysts were more active than the {gamma}-Al{sub 2}O{sub 3} based catalysts. The highest conversion was obtained over a ZSM-5 catalyst prepared by introduction of Pd during synthesis of the zeolite and subsequently ion-exchanged with copper. (author)

  2. Comparative effect of ethylene oxide and gamma irradiation on the chemical, sensory and microbial quality of ginger, cinnamon, fennel and fenugreek

    International Nuclear Information System (INIS)

    Toofanian, F.; Stegeman, H.

    1988-01-01

    The effect of gamma irradiation and ethylene oxide fumigation on the microbiological and sensory properties and on the volatile oil content of ground cinnamon, ginger and fennel as well as on the sensory properties of fenugreek were investigated. It was found that for cinnamon and ginger a 6 kGy dose, for fennel 6-10 kGy and for fenugreek 6-8 kGy dose were equal in microbial effects to the commercially established fumigation process. No significant change in the volatile oil contents of the fumigated or irradiated cinnamon and fennel has been observed. Between the untreated, irradiated or fumigated spices no major differences in sensory properties were found. (author) 13 refs.; 1 fig.; 5 tabs

  3. Increased charge transfer of Poly (ethylene oxide) based electrolyte by addition of small molecule and its application in dye-sensitized solar cells

    International Nuclear Information System (INIS)

    Muthuraaman, B.; Will, Geoffrey; Wang, Hongxia; Moonie, Paul; Bell, John

    2013-01-01

    A Poly (ethylene oxide) based polymer electrolyte impregnated with 2-Mercapto benzimidazole was comprehensively characterized by XRD, UV–visible spectroscopy, FTIR as well as electrochemical impedance spectroscopy. It was found that the crystallization of PEO was dramatically reduced and the ionic conductivity of the electrolyte was increased 4.5 fold by addition of 2-Mercapto benzimidazole. UV–visible and FTIR spectroscopes indicated the formation of charge transfer complex between 2-Mercapto benzimidazole and iodine of the electrolyte. Dye-sensitized solar cells with the polymer electrolytes were assembled. It was found that both the photocurrent density and photovoltage were enhanced with respect to the DSC without 2-Mercapto benzimidazole, leading to a 60% increase of the performance of the cell.

  4. Synthesis and Properties of High Strength Thin Film Composites of Poly(ethylene Oxide and PEO-PMMA Blend with Cetylpyridinium Chloride Modified Clay

    Directory of Open Access Journals (Sweden)

    Mohammad Saleem Khan

    2015-01-01

    Full Text Available Ion-conducting thin film composites of polymer electrolytes were prepared by mixing high MW poly(ethylene oxide (PEO, poly(methyl methacrylate (PMMA as a polymer matrix, cetylpyridinium chloride (CPC modified MMT as filler, and different content of LiClO4 by using solution cast method. The crystallinity, ionic conductivity (σ, and mechanical properties of the composite electrolytes and blend composites were evaluated by using XRD, AC impedance, and UTM studies, respectively. The modification of clay by CPC showed enhancement in the d-spacing. The loading of clay has effect on crystallinity of PEO systems. Blend composites showed better mechanical properties. Young’s modulus and elongation at break values showed increase with salt and clay incorporation in pure PEO. The optimum composition composite of PEO with 3.5 wt% of salt and 3.3 wt% of CPMMT exhibited better performance.

  5. Sterilization of health care products - Ethylene oxide - Part 1: Requirements for development, validation and routine control of a sterilization process for medical devices

    International Nuclear Information System (INIS)

    2007-01-01

    This part of ISO 11135 describes requirements that, if met, will provide an ethylene oxide sterilization process intended to sterilize medical devices, which has appropriate microbicidal activity. Furthermore, compliance with the requirements ensures that this activity is both reliable and reproducible so that it can be predicted, with reasonable confidence, that there is a low level of probability of there being a viable microorganism present on product after sterilization. Specification of this probability is a matter for regulatory authorities and may vary from country to country. The paper provides information on scope, normative references, terms and definitions, quality management systems, sterilizing agent characterization, process and equipment characterization, product definition, process definition, validation, routine monitoring and control, product release from sterilization and maintaining process effectiveness followed by Annex A (Determination of lethal rate of the sterilization process - Biological indicator/bioburden approach), Annex B (Conservative determination of lethal rate of the sterilization process - Overkill approach, annex C (General guidance) and a bibliography.

  6. Ethylene glycol blood test

    Science.gov (United States)

    ... this page: //medlineplus.gov/ency/article/003564.htm Ethylene glycol blood test To use the sharing features ... enable JavaScript. This test measures the level of ethylene glycol in the blood. Ethylene glycol is a ...

  7. Cooperative ethylene receptor signaling

    OpenAIRE

    Liu, Qian; Wen, Chi-Kuang

    2012-01-01

    The gaseous plant hormone ethylene is perceived by a family of five ethylene receptor members in the dicotyledonous model plant Arabidopsis. Genetic and biochemical studies suggest that the ethylene response is suppressed by ethylene receptor complexes, but the biochemical nature of the receptor signal is unknown. Without appropriate biochemical measures to trace the ethylene receptor signal and quantify the signal strength, the biological significance of the modulation of ethylene responses ...

  8. Effect of the structure of commercial poly(ethylene oxide-b-propylene oxide) demulsifier bases on the demulsification of water-in-crude oil emulsions: elucidation of the demulsification mechanism

    Energy Technology Data Exchange (ETDEWEB)

    Ramalho, Joao Batista V.S. [PETROBRAS S.A., Rio de Janeiro, RJ (Brazil). Centro de Pesquisas; Lechuga, Fernanda C.; Lucas, Elizabete F., E-mail: elucas@ima.ufrj.b [Universidade Federal do Rio de Janeiro (UFRJ), RJ (Brazil). Inst. de Macromoleculas Profa. Eloisa Mano

    2010-07-01

    Water-in-crude oil emulsions are formed during petroleum production and asphaltenes play an important role in their stabilization. Demulsifiers are added to destabilize such emulsions,however the demulsification mechanism is not completely known. In this paper, the performances of commercial poly(ethylene oxide-b-propylene oxide) demulsifiers were studied using synthetic water-in-oil emulsions and model-systems (asphaltenes in organic solvent). No change in the asphaltene aggregate size induced by the demulsifier was observed. The demulsification performance decreased as the asphaltene aggregate size increased, so it can be suggested that the demulsification mechanism is correlated to the voids between the aggregates adsorbed on the water droplets surface. (author)

  9. Effect of the structure of commercial poly(ethylene oxide-b-propylene oxide) demulsifier bases on the demulsification of water-in-crude oil emulsions: elucidation of the demulsification mechanism

    International Nuclear Information System (INIS)

    Ramalho, Joao Batista V.S.; Lechuga, Fernanda C.; Lucas, Elizabete F.

    2010-01-01

    Water-in-crude oil emulsions are formed during petroleum production and asphaltenes play an important role in their stabilization. Demulsifiers are added to destabilize such emulsions,however the demulsification mechanism is not completely known. In this paper, the performances of commercial poly(ethylene oxide-b-propylene oxide) demulsifiers were studied using synthetic water-in-oil emulsions and model-systems (asphaltenes in organic solvent). No change in the asphaltene aggregate size induced by the demulsifier was observed. The demulsification performance decreased as the asphaltene aggregate size increased, so it can be suggested that the demulsification mechanism is correlated to the voids between the aggregates adsorbed on the water droplets surface. (author)

  10. Effect of the structure of commercial poly(ethylene oxide-b-propylene oxide demulsifier bases on the demulsification of water-in-crude oil emulsions: elucidation of the demulsification mechanism

    Directory of Open Access Journals (Sweden)

    João Batista V. S. Ramalho

    2010-01-01

    Full Text Available Water-in-crude oil emulsions are formed during petroleum production and asphaltenes play an important role in their stabilization. Demulsifiers are added to destabilize such emulsions,however the demulsification mechanism is not completely known. In this paper, the performances of commercial poly(ethylene oxide-b-propylene oxide demulsifiers were studied using synthetic water-in-oil emulsions and model-systems (asphaltenes in organic solvent. No change in the asphaltene aggregate size induced by the demulsifier was observed. The demulsification performance decreased as the asphaltene aggregate size increased, so it can be suggested that the demulsification mechanism is correlated to the voids between the aggregates adsorbed on the water droplets surface.

  11. Evaluation of the anti-oxidant ethylene diurea (EDU) as a protectant against ozone effects on crops (Growth chamber trials)

    Energy Technology Data Exchange (ETDEWEB)

    Archambault, D.J.; Li, X. [Alberta Research Council, Vegreville, AB (Canada). Environmental Technologies

    2003-02-01

    A field study conducted during the summer of 2000 showed that when the antioxidant ethylene diurea (EDU) was applied to crops there was an increase in several parameters. The authors designed a series of controlled-environment trials to test the following: were the effects of EDU the result of EDU-mediated protection against ozone (O{sub 3}) or were they from the plant growth promoting effects of EDU independent of O{sub 3}. The three major objectives were: (1) to modify an existing gas exposure system to expose plants to O{sub 3} and to test the stability and reliability of the system, (2) to perform O{sub 3} exposure trials using wheat, barley, field pea and canola to observe the effects of O{sub 3}, and (3) to test whether the effects of EDU could be attributed to protection against O{sub 3} injury or to the plant growth promoting effects independent of O{sub 3}. The modification to the gas exposure system involved the installation of an O{sub 3} delivery system and a monitoring system. Stability of the system was tested using radish plants. The symptoms of O{sub 3} injury on radish leaves began after two weeks of exposure. It appeared as mottled bleached areas which became red. Mottled chlorotic areas appeared on wheat and barley, which led to complete chlorosis, necrosis and eventually abscission. After two weeks of exposure, field pea developed tendril curl, and canola plants displayed no visible signs of injury from O{sub 3} exposure. The results of the study indicated that the effects of EDU can be species- and cultivar-specific. 15 refs., 11 tabs., 8 figs.

  12. Measurement of Activity Coefficients of Solvents in Poly ( ethylene oxide ) Using Gas-Chromatographic Method and Correlation by Polymer-ASOG; Poriechirenokishido chu no yobai katsuryo keisu no gasukuromatogurafu ho ni yoru sokutei to Polymer-ASOG ni yoru sokan

    Energy Technology Data Exchange (ETDEWEB)

    Tochigi, K.; Kurita, S.; Ohashi, M. [Yuki Gosei Kogyo Co. LTd., (Japan); Kojima, K. [Nihon University, Tokyo (Japan). Department of Industrial Chemistry

    1997-09-01

    Infinite dilution activity coefficients (353.15-393.15 K) of six solvents (benzene, toluene, p-xylene, cyclohexane, acetone and methylethylketone) and activity coefficient at finite concentrations (353.15 K, 373.15 K) of these solvents in poly (ethylene oxide) are measured using gas-chromatographic method. The experimental data are then correlated by a polymer-ASOG model. 18 refs., 2 figs., 3 tabs.

  13. Preparation, properties and biological application of pH-sensitive poly(ethylene oxide) (PEO) hydrogels grafted with acrylic acid(AAc) using gamma-ray irradiation

    International Nuclear Information System (INIS)

    Nho, Y.C.; Mook Lim, Youn; Moo Lee, Young

    2004-01-01

    pH-sensitive hydrogels were studied as a drug carrier for the protection of insulin from the acidic environment of the stomach before releasing it in the small intestine. In this study, hydrogels based on poly(ethylene oxide) (PEO) networks grafted with acrylic acid (AAc) were prepared via a two-step process. PEO hydrogels were prepared by γ-ray irradiation, and then grafting by AAc monomer onto the PEO hydrogels with the subsequent irradiation (radiation dose: 5-20 kGy, dose rate: 2.15 kGy/h). These grafted hydrogels showed a pH-sensitive swelling behavior. The grafted hydrogels were used as a carrier for the drug delivery systems for the controlled release of insulin. The in vitro drug release behaviors of these hydrogels were examined by quantification analysis with a UV/VIS spectrophotometer. Insulin was loaded into freeze-dried hydrogels (7 mmx3 mmx2.5 mm) and administrated orally to healthy and diabetic Wistar rats. The oral administration of insulin-loaded hydrogels to Wistar rats decreased the blood glucose levels obviously for at least 4 h due to the absorption of insulin in the gastrointestinal tract

  14. Stealth properties of poly(ethylene oxide)-based triblock copolymer micelles: a prerequisite for a pH-triggered targeting system.

    Science.gov (United States)

    Van Butsele, K; Morille, M; Passirani, C; Legras, P; Benoit, J P; Varshney, S K; Jérôme, R; Jérôme, C

    2011-10-01

    Evaluation of the biocompatibility of pH-triggered targeting micelles was performed with the goal of studying the effect of a poly(ethylene oxide) (PEO) coating on micelle stealth properties. Upon protonation under acidic conditions, pH-sensitive poly(2-vinylpyridine) (P2VP) blocks were stretched, exhibiting positive charges at the periphery of the micelles as well as being a model targeting unit. The polymer micelles were based on two different macromolecular architectures, an ABC miktoarm star terpolymer and an ABC linear triblock copolymer, which combined three different polymer blocks, i.e. hydrophobic poly(ε-caprolactone), PEO and P2VP. Neutral polymer micelles were formed at physiological pH. These systems were tested for their ability to avoid macrophage uptake, their complement activation and their pharmacological behavior after systemic injection in mice, as a function of their conformation (neutral or protonated). After protonation, complement activation and macrophage uptake were up to twofold higher than for neutral systems. By contrast, when P2VP blocks and the targeting unit were buried by the PEO shell at physiological pH, micelle stealth properties were improved, allowing their future systemic injection with an expected long circulation in blood. Smart systems responsive to pH were thus developed which therefore hold great promise for targeted drug delivery to an acidic tumoral environment. Copyright © 2011 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

  15. High Ionic Conductivity of Composite Solid Polymer Electrolyte via In Situ Synthesis of Monodispersed SiO2 Nanospheres in Poly(ethylene oxide).

    Science.gov (United States)

    Lin, Dingchang; Liu, Wei; Liu, Yayuan; Lee, Hye Ryoung; Hsu, Po-Chun; Liu, Kai; Cui, Yi

    2016-01-13

    High ionic conductivity solid polymer electrolyte (SPE) has long been desired for the next generation high energy and safe rechargeable lithium batteries. Among all of the SPEs, composite polymer electrolyte (CPE) with ceramic fillers has garnered great interest due to the enhancement of ionic conductivity. However, the high degree of polymer crystallinity, agglomeration of ceramic fillers, and weak polymer-ceramic interaction limit the further improvement of ionic conductivity. Different from the existing methods of blending preformed ceramic particles with polymers, here we introduce an in situ synthesis of ceramic filler particles in polymer electrolyte. Much stronger chemical/mechanical interactions between monodispersed 12 nm diameter SiO2 nanospheres and poly(ethylene oxide) (PEO) chains were produced by in situ hydrolysis, which significantly suppresses the crystallization of PEO and thus facilitates polymer segmental motion for ionic conduction. In addition, an improved degree of LiClO4 dissociation can also be achieved. All of these lead to good ionic conductivity (1.2 × 10(-3) S cm(-1) at 60 °C, 4.4 × 10(-5) S cm(-1) at 30 °C). At the same time, largely extended electrochemical stability window up to 5.5 V can be observed. We further demonstrated all-solid-state lithium batteries showing excellent rate capability as well as good cycling performance.

  16. Novel differential refractometry study of the enzymatic degradation kinetics of poly(ethylene oxide)-b-poly(epsilon-caprolactone) particles dispersed in water.

    Science.gov (United States)

    Lam, HiuFung; Gong, Xiangjun; Wu, Chi

    2007-02-22

    A poly(ethylene oxide)-b-poly(epsilon-caprolactone) (PEO-b-PCL) diblock copolymer was micronized into small micelle-like particles (approximately 80 nm) via dialysis-induced microphase inversion. The enzymatic biodegradation of the PCL portion of these particles in water was in situ investigated inside a recently developed novel differential refractometer. Using this refractometry method, we were able to monitor the real-time biodegradation via the refractive index change (Deltan) of the dispersion because Deltan is directly proportional to the particle mass concentration. We found that the degradation rate is proportional to either the polymer or enzyme concentration. Our results directly support previous speculation on the basis of the light-scattering data that the biodegradation follows the first-order kinetics for a given enzyme concentration. This study not only leads to a better understanding of the enzymatic biodegradation of PCL, but also demonstrates a novel, rapid, noninvasive, and convenient way to test the degradability of polymers.

  17. Impact of gamma irradiation on porosity and pore distribution of poly [ethylene-oxide] films: correlation with dielectric and microstructural properties

    Science.gov (United States)

    Saha, Mou; Mukhopadhyay, Madhumita; Ray, Ruma

    2018-03-01

    The structure and morphology of polymers are significantly altered upon exposure to high energy gamma irradiation either through bond breakage i.e. scission or cross-linkage. The present article reports the influence of gamma radiation (1-20 kGy) on the distribution of molecular weight and porosity of the films prepared using irradiated and unirradiated poly-[ethylene oxide] (PEO) powder. The PEO films exhibit pore dimension in the range of 20-500 nm. Selective irradiation is capable of tailoring the pore-size and reducing the multimodal trait to uni-or bimodal upon high energy perturbation. The porosity of PEO films is determined from both 2D-pore surface calculation from SEM images and compared with 3D-BET porosity. Correlation is established among dielectric constant (ɛ') and porosity. The magnitude of ɛ' increases sharply towards low frequency due to electrode polarization effects. Relaxation time is found to be highest and comparable for 1 and 10 KGy. With increase in irradiation dose, scission is predominant, owing to which smaller polymer fragments are produced which are able to follow fast frequency regime and thereby relax at lesser time.

  18. S-containing copolymer as cathode material in poly(ethylene oxide)-based all-solid-state Li-S batteries

    Science.gov (United States)

    Gracia, Ismael; Ben Youcef, Hicham; Judez, Xabier; Oteo, Uxue; Zhang, Heng; Li, Chunmei; Rodriguez-Martinez, Lide M.; Armand, Michel

    2018-06-01

    Inverse vulcanization copolymers (p(S-DVB)) from the radical polymerization of elemental sulfur and divinylbenzene (DVB) have been studied as cathode active materials in poly(ethylene oxide) (PEO)-based all-solid-state Li-S cells. The Li-S cell comprising the optimized p(S-DVB) cathode (80:20 w/w S/DVB ratio) and lithium bis(fluorosulfonyl)imide/PEO (LiFSI/PEO) electrolyte shows high specific capacity (ca. 800 mAh g-1) and high Coulombic efficiency for 50 cycles. Most importantly, polysulfide (PS) shuttle is highly mitigated due to the strong interactions of PS species with polymer backbone in p(S-DVB). This is demonstrated by the stable cycling of the p(S-DVB)-based cell using lithium bis(trifluoromethanesulfonyl)imide (LiTFSI)/PEO electrolyte, where successful charging cannot be achieved even at the first cycle with plain elemental S-based cathode material due to the severe PS shuttle phenomenon. These results suggest that inverse vulcanization copolymers are promising alternatives to elemental sulfur for enhancing the electrochemical performance of PEO-based all-solid-state Li-S cells.

  19. Facile Synthesis and Characterization of N-Doped TiO2 Photocatalyst and Its Visible-Light Activity for Photo-Oxidation of Ethylene

    Directory of Open Access Journals (Sweden)

    Yu-Hao Lin

    2015-01-01

    Full Text Available A facile wet chemical method was adopted for preparing highly photoactive nitrogen doped TiO2 (N-TiO2 powders with visible responsive capability, which could be achieved by the hydrolysis of titanium isopropoxide (TTIP in the ammonium hydroxide precursor solution in various concentrations and then calcined at different temperatures. The N-TiO2 powders were characterized, and the photocatalytic activity was evaluated for the photocatalytic oxidation of ethylene gas under visible light irradiation to optimize the synthesizing conditions of N-TiO2 catalyst. The N-TiO2 photocatalytic powders were calcined in a range of temperatures from 300 to 600°C and obviously found to have greater photocatalytic activities than commercial TiO2 P25. The strong absorption in the visible light region could be ascribed to good crystallization and adapted sinter temperature of as prepared sample. XPS test demonstrated that the N was doped into TiO2 lattice and made an interstitial formation (Ti-O-N, and N doping also retarded the phase transformation from anatase to rutile as well. The N-TiO2 catalyst prepared with 150 mL ammonium hydroxide added and calcined at 500°C showed the best photocatalytic activity. The experimental results also proved the enhanced photoactivity of N-TiO2 material depends on the synthesizing conditions.

  20. Poly(ethyl glyoxylate)-Poly(ethylene oxide) Nanoparticles: Stimuli-Responsive Drug Release via End-to-End Polyglyoxylate Depolymerization.

    Science.gov (United States)

    Fan, Bo; Gillies, Elizabeth R

    2017-08-07

    The ability to disrupt polymer assemblies in response to specific stimuli provides the potential to release drugs selectively at certain sites or conditions in vivo. However, most stimuli-responsive delivery systems require many stimuli-initiated events to release drugs. "Self-immolative polymers" offer the potential to provide amplified responses to stimuli as they undergo complete end-to-end depolymerization following the cleavage of a single end-cap. Herein, linker end-caps were developed to conjugate self-immolative poly(ethyl glyoxylate) (PEtG) with poly(ethylene oxide) (PEO) to form amphiphilic block copolymers. These copolymers were self-assembled to form nanoparticles in aqueous solution. Cleavage of the linker end-caps were triggered by a thiol reducing agent, UV light, H 2 O 2 , and combinations of these stimuli, resulting in nanoparticle disintegration. Low stimuli concentrations were effective in rapidly disrupting the nanoparticles. Nile red, doxorubin, and curcumin were encapsulated into the nanoparticles and were selectively released upon application of the appropriate stimulus. The ability to tune the stimuli-responsiveness simply by changing the linker end-cap makes this new platform highly attractive for applications in drug delivery.

  1. Fetal anomalies produced subsequent to treatment of zygotes with ethylene oxide or ethyl methanesulfonate are not likely due to the usual genetic causes.

    Science.gov (United States)

    Katoh, M; Cacheiro, N L; Cornett, C V; Cain, K T; Rutledge, J C; Generoso, W M

    1989-02-01

    Earlier studies in this laboratory revealed that ethylene oxide (EtO) or ethyl methanesulfonate (EMS) induced high frequencies of midgestation and late fetal deaths, and of malformations among some of the surviving fetuses, when female mice were exposed at the time of fertilization of their eggs or during the early pronuclear stage of the zygote. Effects of the two mutagens are virtually identical. Thus, in investigating the mechanisms responsible for the dramatic effects in the early pronuclear zygotes, the two compounds were used interchangeably in the experiments. First, a reciprocal zygote-transfer study was conducted in order to determine whether the effect is directly on the zygotes or indirectly through maternal toxicity. And second, cytogenetic analyses of pronuclear metaphases, early cleavage embryos, and midgestation fetuses were carried out. The zygote transplantation experiment rules out maternal toxicity as a factor in the fetal maldevelopment. Together with the strict stage specificity observed in the earlier studies, this result points to a genetic cause for the abnormalities. However, the cytogenetic studies failed to show structural or numerical chromosome aberrations. Since intragenic base changes and deletions may also be ruled out, it appears that the lesions in question induced in zygotes by the two mutagens are different from conventional ones and, therefore, could be a novel one in experimental mammalian mutagenesis. Alternatively, the mechanism could involve a non-mutational 'imprinting' process that caused changes in gene expression.

  2. Single-molecule tracking studies of flow-induced microdomain alignment in cylinder-forming polystyrene-poly(ethylene oxide) diblock copolymer films.

    Science.gov (United States)

    Tran-Ba, Khanh-Hoa; Higgins, Daniel A; Ito, Takashi

    2014-09-25

    Flow-based approaches are promising routes to preparation of aligned block copolymer microdomains within confined spaces. An in-depth characterization of such nanoscale morphologies within macroscopically nonuniform materials under ambient conditions is, however, often challenging. In this study, single-molecule tracking (SMT) methods were employed to probe the flow-induced alignment of cylindrical microdomains (ca. 22 nm in diameter) in polystyrene-poly(ethylene oxide) diblock copolymer (PS-b-PEO) films. Films of micrometer-scale thicknesses were prepared by overlaying a benzene solution droplet on a glass coverslip with a rectangular glass plate, followed by solvent evaporation under a nitrogen atmosphere. The microdomain alignment was quantitatively assessed from SMT data exhibiting the diffusional motions of individual sulforhodamine B fluorescent probes that preferentially partitioned into cylindrical PEO microdomains. Better overall microdomain orientation along the flow direction was observed near the substrate interface in films prepared at a higher flow rate, suggesting that the microdomain alignment was primarily induced by shear flow. The SMT data also revealed the presence of micrometer-scale grains consisting of highly ordered microdomains with coherent orientation. The results of this study provide insights into shear-based preparation of aligned cylindrical microdomains in block copolymer films from solutions within confined spaces.

  3. CO2-Free Power Generation on an Iron Group Nanoalloy Catalyst via Selective Oxidation of Ethylene Glycol to Oxalic Acid in Alkaline Media

    Science.gov (United States)

    Matsumoto, Takeshi; Sadakiyo, Masaaki; Ooi, Mei Lee; Kitano, Sho; Yamamoto, Tomokazu; Matsumura, Syo; Kato, Kenichi; Takeguchi, Tatsuya; Yamauchi, Miho

    2014-07-01

    An Fe group ternary nanoalloy (NA) catalyst enabled selective electrocatalysis towards CO2-free power generation from highly deliverable ethylene glycol (EG). A solid-solution-type FeCoNi NA catalyst supported on carbon was prepared by a two-step reduction method. High-resolution electron microscopy techniques identified atomic-level mixing of constituent elements in the nanoalloy. We examined the distribution of oxidised species, including CO2, produced on the FeCoNi nanoalloy catalyst in the EG electrooxidation under alkaline conditions. The FeCoNi nanoalloy catalyst exhibited the highest selectivities toward the formation of C2 products and to oxalic acid, i.e., 99 and 60%, respectively, at 0.4 V vs. the reversible hydrogen electrode (RHE), without CO2 generation. We successfully generated power by a direct EG alkaline fuel cell employing the FeCoNi nanoalloy catalyst and a solid-oxide electrolyte with oxygen reduction ability, i.e., a completely precious-metal-free system.

  4. Effect of Drug Loading Method and Drug Physicochemical Properties on the Material and Drug Release Properties of Poly (Ethylene Oxide Hydrogels for Transdermal Delivery

    Directory of Open Access Journals (Sweden)

    Rachel Shet Hui Wong

    2017-07-01

    Full Text Available Novel poly (ethylene oxide (PEO hydrogel films were synthesized via UV cross-linking with pentaerythritol tetra-acrylate (PETRA as cross-linking agent. The purpose of this work was to develop a novel hydrogel film suitable for passive transdermal drug delivery via skin application. Hydrogels were loaded with model drugs (lidocaine hydrochloride (LID, diclofenac sodium (DIC and ibuprofen (IBU via post-loading and in situ loading methods. The effect of loading method and drug physicochemical properties on the material and drug release properties of medicated film samples were characterized using scanning electron microscopy (SEM, swelling studies, differential scanning calorimetry (DSC, fourier transform infrared spectroscopy (FT-IR, tensile testing, rheometry, and drug release studies. In situ loaded films showed better drug entrapment within the hydrogel network and also better polymer crystallinity. High drug release was observed from all studied formulations. In situ loaded LID had a plasticizing effect on PEO hydrogel, and films showed excellent mechanical properties and prolonged drug release. The drug release mechanism for the majority of medicated PEO hydrogel formulations was determined as both drug diffusion and polymer chain relaxation, which is highly desirable for controlled release formulations.

  5. Synthesis and shape control of uniform polymer microparticles by tailored adsorption of poly(ethylene oxide)-b-Poly(ε-caprolactone) copolymer

    Energy Technology Data Exchange (ETDEWEB)

    Acter, Shahinur; Cho, Jang Woo; Kim, Jeong Won; Byun, Aram; Park, Kyoung Ho; Kim, Jin Woong [Hanyang University, Ahnsan (Korea, Republic of)

    2015-05-15

    This paper introduces a straightforward and robust polymerization method for the synthesis of uniform polymer microparticles having controlled surface chemistry as well as tailored particle shapes. Uniform polystyrene (PS) microparticles are produced by dispersion polymerization, in which amphiphilic poly(ethylene oxide)-b-poly(ε-caprolactone) (PEO-b-PCL) copolymers anchor on to the growing polymer particles and stabilize them by steric repulsion. We have observed that, when PEO-b-PCL copolymers are incorporated at the proper concentration range, the total number of particles remains unchanged after the formation of primary particles, which is essential for maintaining size uniformity. Otherwise, nonuniform PS microparticles are produced mainly as a result of the coagulation or secondary formation of particles. To show the diversity of our particle synthesis technology, shape-controlled microparticles, such as dimples and Janus particles, are also produced by using temperature-mediated swelling and phase separation. Finally, we show that PEO-b-PCL copolymers play a key role in regulating the surface wettability of the seed particles, thereby facilitating the formation of anisotropic microparticles.

  6. Nanofiber mats composed of a chitosan-poly(d,l-lactic-co-glycolic acid)-poly(ethylene oxide) blend as a postoperative anti-adhesion agent.

    Science.gov (United States)

    Ko, Jae Eok; Ko, Young-Gwang; Kim, Won Il; Kwon, Oh Kyoung; Kwon, Oh Hyeong

    2017-10-01

    Postoperative tissue adhesion causes serious complications and suffering in 90% of patients after peritoneum surgery, while commercial anti-adhesion agents cannot completely prevent postoperative peritoneal adhesions. This study demonstrates electrospining of a blended solution of chitosan, poly(d,l-lactic-co-glycolic acid) (PLGA), and poly(ethylene oxide) (PEO) to fabricate a chitosan-based nanofibrous mat as a postoperative anti-adhesion agent. Rheological studies combined with scanning electron microscopy reveal that the spinnability of the chitosan-PLGA solution could be controlled by adjusting the blend ratio and concentration with average fiber diameter from 634 to 913 nm. Biodegradation of the nanofiber specimens showed accelerated hydrolysis by chitosan. Proliferation of fibroblasts and antimicrobial activity of nanofibers containing chitosan was analyzed. Abdominal defects with cecum adhesion in rats demonstrated that the blend nanofiber mats were effective in preventing tissue adhesion as a barrier (4 weeks after abdominal surgery) by coverage of exfoliated peritoneum and insufficient wound sites at the beginning of the wound healing process. Chitosan-PLGA-PEO blend nanofiber mats will provide a promising key as a postoperative anti-adhesion agent. © 2016 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 105B: 1906-1915, 2017. © 2016 Wiley Periodicals, Inc.

  7. Importance of poly(ethylene oxide)-modification and chloride anion for the electron transfer reaction of cytochrome c in 1-ethyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide

    International Nuclear Information System (INIS)

    Ohno, Hiroyuki; Suzuki, Chiiko; Fujita, Kyoko

    2006-01-01

    Horse heart cytochrome c (cyt c) was chemically modified with poly(ethylene oxide) (PEO) to dissolve it in room temperature ionic liquid 1-ethyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide ([emim][TFSI]). The redox response of the modified cyt c, hereafter PEO-cyt c, was analyzed in [emim][TFSI]. PEO modification to the surface of cyt c, which exceeded 60% of the total mass of the PEO-cyt c, was an effective method to solubilize the cyt c. In spite of the high ion density and sufficient ionic conductivity of [emim][TFSI], no redox response of pure PEO-cyt c was detected. However, a reversible redox response of PEO-cyt c was observed after adding a simple electrolyte such as KCl to [emim][TFSI]. The redox response of PEO-cyt c was sensitive to the anion radius of the added salt, and the chloride anion was found to be the best anion species to produce a redox response of PEO-cyt c in [emim][TFSI]. However, above a certain salt concentration, the resulting increase in solution viscosity would suppress the redox reaction. The results strongly indicate that the chloride anions, because of their mobility in the polypeptide matrix, compensate the charge change of heme during the electron transfer reaction. Larger anions did not show such an effect due to sterical restrictions on the migration through the protein shell to the heme pocket of cyt c

  8. Crystallization and melting behavior of poly(ethylene oxide) and its blend with styrene-based ionomer using time-resolved SAXS/WAXS experiments

    Energy Technology Data Exchange (ETDEWEB)

    Slusarczyk, CzesLaw, E-mail: cslusarczyk@ath.bielsko.pl [Institute of Textile Engineering and Polymer Materials, University of Bielsko-BiaLa, ul. Willowa 2, 43-309 Bielsko-BiaLa (Poland)

    2011-10-15

    Time-resolved synchrotron wide- and small-angle X-ray scattering experiments were used to investigate the crystallization behavior and microstructure development of neat poly(ethylene oxide) (PEO) and its 50/50 blend with ionomer containing 6.4 mol% of sodium acrylate. The apparent lateral crystal sizes D{sub (120)} and D{sub (112)/(004)} were derived from the WAXS profiles. It was found that D{sub (120)} and D{sub (112)/(004)} of PEO in the blend are almost independent of temperature and are smaller when compared to those of neat PEO sample. The evolution of morphological parameters extracted from time-resolved SAXS profiles such as the long period L, the lamellar crystal thickness l{sub C} and the amorphous layer thickness l{sub A}, shows that the crystallization process of neat PEO follows the nucleation theory. The lamellar crystal thickness l{sub C} shows a single linear dependence on inverse supercooling, over the whole temperature range investigated. In contrast, the crystallization process of PEO in the blend (i.e. in the presence of interactions with the ionomer) follows the nucleation theory only in the narrow supercooling range. It was found also that the morphology of the blend consists of a broad population of lamellar crystal thicknesses. During heating lamellae melt in the reversed sequence of their formation.

  9. Tailored Design of Bicontinuous Gyroid Mesoporous Carbon and Nitrogen-Doped Carbon from Poly(ethylene oxide-b-caprolactone) Diblock Copolymers.

    Science.gov (United States)

    Chu, Wei-Cheng; Bastakoti, Bishnu Prasad; Kaneti, Yusuf Valentino; Li, Jheng-Guang; Alamri, Hatem R; Alothman, Zeid A; Yamauchi, Yusuke; Kuo, Shiao-Wei

    2017-10-04

    Highly ordered mesoporous resol-type phenolic resin and the corresponding mesoporous carbon materials were synthesized by using poly(ethylene oxide-b-caprolactone) (PEO-b-PCL) diblock copolymer as a soft template. The self-assembled mesoporous phenolic resin was found to form only in a specific resol concentration range of 40-70 wt % due to an intriguing balance of hydrogen-bonding interactions in the resol/PEO-b-PCL mixtures. Furthermore, morphological transitions of the mesostructures from disordered to gyroid to cylindrical and finally to disordered micelle structure were observed with increasing resol concentration. By calcination under nitrogen atmosphere at 800 °C, the bicontinuous mesostructured gyroid phenolic resin could be converted to mesoporous carbon with large pore size without collapse of the original mesostructure. Furthermore, post-treatment of the mesoporous gyroid phenolic resin with melamine gave rise to N-doped mesoporous carbon with unique electronic properties for realizing high CO 2 adsorption capacity (6.72 mmol g -1 at 0 °C). © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  10. The effects of ethylene oxide containing lipopolymers and tri-block copolymers on lipid bilayers of dipalmitoylphosphatidylcholine

    DEFF Research Database (Denmark)

    Baekmark, T. R.; Pedersen, S.; Jorgensen, K.

    1997-01-01

    oxide moity, anchored to the bilayer by a 1,2-dioctadecanoyl-s,n-glycero-3-phosphoethanolamine (DC18PE) lipid. The second type, which is a novel type of membrane-spanning object, is an amphiphilic tri-block copolymer composed of two hydrophilic stretches of polyethylene oxide separated by a hydrophobic...... stretch of polystyrene. Hence the tri-block copolymer may act as a membrane-spanning macromolecule mimicking an amphiphilic protein or polypeptide. Differential scanning calorimetry is used to determine a partial phase diagram for the lipopolymer systems and to assess the amount of lipopolymer that can...... be loaded into DC16PC lipid bilayers before micellization takes place. Unilamellar and micellar phase structures are investigated by fluorescence quenching using bilayer permeating dithionite. The chain length-dependent critical lipopolymer concentration, denoting the lamellar-to-micellar phase transition...

  11. The formation and growing properties of poly(ethylene terephthalate) fiber growing media after thermo-oxidative treatment

    International Nuclear Information System (INIS)

    Chang, C.P.; Lin, S.M.

    2007-01-01

    This research uses three kinds of recycled synthetic fibers that all possess excellent thermal plasticity property as raw material to develop a new firm cultivation media: polyethylene terephthalate, polyamide and polypropylene. One can not only freely control plants cultivation growing condition by changing bulk density of the media, but also solve disposal problem after usage by applying thermal oxidative treatment during manufacturing processes. The water content, air permeability and formation conditions of these fiber growing media that are required in plants growing habitat were discussed, and compared the fallout with rockwool (RW) growing media that is commonly used at present days. The results indicated that the polyethylene terephthalate fiber media could attain best formation characteristics among these fibers at the same bulk density range. Furthermore, the fiber media that were thermo-oxidative treated at 240-260 deg. C could obtained above 90% total porosity, 23-49% air capacity and 48-68% water availability, water contents raised from 1735-1094 to 2145-1156% under bulk densities of 0.03-0.09 g/cm 3 , which conforms to the common plant growing habitat conditions. Its performance well surpasses the rockwool growing media. We also discovered that the thermo-oxidative treated polyethylene terephthalate (PET) fiber media could be easily broken down and become powdery by exerting pressure, thus greatly reduce its volume and effectively improve disposal processes that are difficult presently for the huge refuse create by rockwool

  12. Targeting α-synuclein oligomers

    DEFF Research Database (Denmark)

    van Diggelen, Femke

    Parkinson’s Disease (PD) is a complex disease, characterised by degeneration of neocortical, limbic and nigrostriatal neurons. It is unknown what initiates neurodegeneration, but soluble oligomers of the protein α-synuclein (αSn) seem to be particularly toxic, compared to insoluble fibrils...... unique characteristics, e.g. they were recognized by different conformational antibodies and DHA–αSOs also formed a second elongated species in addition to the dominant spherical species. Although further functional testing is needed, this suggests that each species has its own distinct toxic mechanism......+/K+ ATPase, V-type ATPase, VDAC, CaMKII and Rab-3A. The identification of these targets is a first step towards unravelling the toxic pathways which are activated upon synaptic binding of extracellularly added αSOs, and hopefully will contribute to the discovery of new disease modifying compounds, which can...

  13. Experimental and theoretical study of the reactions between neutral vanadium oxide clusters and ethane, ethylene, and acetylene.

    Science.gov (United States)

    Dong, Feng; Heinbuch, Scott; Xie, Yan; Rocca, Jorge J; Bernstein, Elliot R; Wang, Zhe-Chen; Deng, Ke; He, Sheng-Gui

    2008-02-13

    Reactions of neutral vanadium oxide clusters with small hydrocarbons, namely C2H6, C2H4, and C2H2, are investigated by experiment and density functional theory (DFT) calculations. Single photon ionization through extreme ultraviolet (EUV, 46.9 nm, 26.5 eV) and vacuum ultraviolet (VUV, 118 nm, 10.5 eV) lasers is used to detect neutral cluster distributions and reaction products. The most stable vanadium oxide clusters VO2, V2O5, V3O7, V4O10, etc. tend to associate with C2H4 generating products V(m)O(n)C2H4. Oxygen-rich clusters VO3(V2O5)(n=0,1,2...), (e.g., VO3, V3O8, and V5O13) react with C2H4 molecules to cause a cleavage of the C=C bond of C2H4 to produce (V2O5)(n)VO2CH2 clusters. For the reactions of vanadium oxide clusters (V(m)O(n)) with C2H2 molecules, V(m)O(n)C2H2 are assigned as the major products of the association reactions. Additionally, a dehydration reaction for VO3 + C2H2 to produce VO2C2 is also identified. C2H6 molecules are quite stable toward reaction with neutral vanadium oxide clusters. Density functional theory calculations are employed to investigate association reactions for V2O5 + C2H(x). The observed relative reactivity of C2 hydrocarbons toward neutral vanadium oxide clusters is well interpreted by using the DFT calculated binding energies. DFT calculations of the pathways for VO3+C2H4 and VO3+C2H2 reaction systems indicate that the reactions VO3+C2H4 --> VO2CH2 + H2CO and VO3+C2H2 --> VO2C2 + H2O are thermodynamically favorable and overall barrierless at room temperature, in good agreement with the experimental observations.

  14. High-resolution Kendrick Mass Defect Analysis of Poly(ethylene oxide)-based Non-ionic Surfactants and Their Degradation Products.

    Science.gov (United States)

    Fouquet, Thierry; Shimada, Haruo; Maeno, Katsuyuki; Ito, Kanako; Ozeki, Yuka; Kitagawa, Shinya; Ohtani, Hajime; Sato, Hiroaki

    2017-09-01

    Matrix assisted laser desorption ionization (MALDI) high-resolution mass spectrometry (HRMS) and the recently introduced high-resolution Kendrick mass defect (HRKMD) analysis are combined to thoroughly characterize non-ionic surfactants made of a poly(ethylene oxide) (PEO) core capped by esters of fatty acids. A PEO monostearate surfactant is first analyzed as a proof of principle of the HRKMD analysis conducted with a fraction of EO as the base unit (EO/X with X being an integer) in lieu of EO for a regular KMD analysis. Data visualization is greatly enhanced and the distributions detected in the MALDI mass spectrum are assigned to a pristine (H, OH)-PEO as well as mono- and di-esterified PEO chains with palmitate and stearate end-groups in HRKMD plots computed with EO/45. The MALDI-HRMS/HRKMD analysis is then successfully applied to the more complex case of ethoxylated hydrogenated castor oil (EHCO) found to contain a large number of hydrogenated ricinoleate moieties (up to 14) in its HRKMD plot computed with EO/43, departing from the expected triglyceride structure. The exhaustiveness of the MALDI-HRMS/HRKMD strategy is validated by comparing the so-obtained fingerprints with results from alternative techniques (electrospray ionization MS, size exclusion and liquid adsorption chromatography, ion mobility spectrometry). Finally, aged non-ionic surfactants formed upon hydrolytic degradation are analyzed by MALDI-HRMS/HRKMD to easily assign the degradation products and infer the associated degradation routes. In addition to the hydrolysis of the ester groups observed for EHCO, chain scissions and new polar end-groups are observed in the HRKMD plot of PEO monostearate arising from a competitive oxidative ageing.

  15. Synthesis and Electronic Properties of Length-Defined 9,10-Anthrylene-Butadiynylene Oligomers.

    Science.gov (United States)

    Nagaoka, Maiko; Tsurumaki, Eiji; Nishiuchi, Mai; Iwanaga, Tetsuo; Toyota, Shinji

    2018-05-18

    Linear π-conjugated oligomers consisting of anthracene and diacetylene units were readily synthesized by a one-pot process that involved desilylation and oxidative coupling from appropriate building units. We were able to isolate length-defined oligomers ranging from 2-mer to 6-mer as stable and soluble solids. The bathochromic shifts in the UV-vis spectra suggested that the π-conjugation was extended with elongation of the linear chain. Cyclic voltammetric measurements showed characteristic reversible oxidation waves that were dependent on the number of anthracene units.

  16. Monochloro non-bridged half-metallocene-type zirconium complexes containing phosphine oxide-(thio)phenolate chelating ligands as efficient ethylene polymerization catalysts.

    Science.gov (United States)

    Tang, Xiao-Yan; Wang, Yong-Xia; Liu, San-Rong; Liu, Jing-Yu; Li, Yue-Sheng

    2013-01-14

    A series of novel monochloro half-zirconocene complexes containing phosphine oxide-(thio)phenolate chelating ligands of the type, ClCp'Zr[X-2-R(1)-4-R(2)-6-(Ph(2)P=O)C(6)H(2)](2) (Cp' = C(5)H(5), 2a: X = O, R(1) = Ph, R(2) = H; 2b: X = O, R(1) = F, R(2) = H; 2c: X = O, R(1) = (t)Bu, R(2) = H; 2d: X = O, R(1) = R(2) = (t)Bu; 2e: X = O, R(1) = SiMe(3), R(2) = H; 2f: X = S, R(1) = SiMe(3), R(2) = H; Cp' = C(5)Me(5), 2g: X = O, R(1) = SiMe(3), R(2) = H), have been synthesized in high yields. These complexes were identified by (1)H {(13)C} NMR and elemental analyses. Structures for 2b, 2c and 2f were further confirmed by X-ray crystallography. Structural characterization of these complexes reveals crowded environments around the zirconium. Complexes 2b and 2c adopt six-coordinate, distorted octahedral geometry around the zirconium center, in which the equatorial positions are occupied by three oxygen atoms of two chelating phosphine oxide-bridged phenolate ligands and a chlorine atom. The cyclopentadienyl ring and one oxygen atom of the ligand are coordinated on the axial position. Complex 2f also folds a six-coordinate, distorted octahedral geometry around the Zr center, consisting of a Cp-Zr-O (in P=O) axis [177.16°] and a distorted plane of two sulfur atoms and one oxygen atom of two chelating phosphine oxide-bridged thiophenolate ligands as well as a chlorine atom. When activated by modified methylaluminoxane (MMAO), all the complexes exhibited high activities towards ethylene polymerization at high temperature (75 °C), giving high molecular weight polymers with unimodal molecular weight distribution. The formation of 14-electron, cationic metal alkyl species might come from the Zr-O (in phenol ring) bond cleavage based on the DFT calculations study.

  17. The impact of carbon dioxide and exhaust gas recirculation on the oxidative reactivity of soot from ethylene flames and diesel engines

    Science.gov (United States)

    Al-Qurashi, Khalid O.

    Restrictive emissions standards to reduce nitrogen oxides (NOx) and particulate matter (PM) emissions from diesel engines necessitate the development of advanced emission control technology. The engine manufacturers in the United States have implemented the exhaust gas recirculation (EGR) and diesel particulate filters (DPF) to meet the stringent emissions limits on NOx and PM, respectively. Although the EGR-DPF system is an effective means to control diesel engine emissions, there are some concerns associated with its implementation. The chief concern with this system is the DPF regenerability, which depends upon several factors, among which are the physicochemical properties of the soot. Despite the plethora of research that has been conducted on DPF regenerability, the impact of EGR on soot reactivity and DPF regenerability is yet to be examined. This work concerns the impact of EGR on the oxidative reactivity of diesel soot. It is part of ongoing research to bridge the gap in establishing a relationship between soot formation conditions, properties, and reactivity. This work is divided into three phases. In the first phase, carbon dioxide (CO2) was added to the intake charge of a single cylinder engine via cylinders of compressed CO2. This approach simulates the cold-particle-free EGR. The results showed that inclusion of CO2 changes the soot properties and yields synergistic effects on the oxidative reactivity of the resulting soot. The second phase of this research was motivated by the findings from the first phase. In this phase, post-flame ethylene soot was produced from a laboratory co-flow laminar diffusion flame to better understand the mechanism by which the CO2 affects soot reactivity. This phase was accomplished by successfully isolating the dilution, thermal, and chemical effects of the CO2. The results showed that all of these effects account for a measurable increase in soot reactivity. Nevertheless, the thermal effect was found to be the most

  18. Physiological studies on photochemical oxidant injury in rice plants. II. Effect of abscisic acid (ABA) on ozone injury and ethylene production in rice plants

    Energy Technology Data Exchange (ETDEWEB)

    Jeong, Y.H.; Nakamura, H.; Ota, Y.

    1981-12-01

    In order to determine the effect of ABA on ozone injury to rice plants, ethylene production, rate of chlorophyll retention and ozone-sensitivity of rice plants pretreated with ABA solution were investigated. The experiments were carried out in pots using rice plants at the 7-8 leaf stage. The results obtained are summarized as follows: ethylene production by the leaf blades exposed to ozone increased with the increase in the dosage of ozone; ethylene production was higher in cv. Nihonbare which was more sensitive to ozone than in cv. Tongil; pre-treatment with ABA solution one hour before ozone treatment reduced ethylene production by the leaf blades exposed to ozone; and the rate of chlorophyll retention decreased following injury, but increased remarkably by the pre-treatment with ABA solution. In conclusion, it could be demonstrated that ozone injury of rice plants can be reduced by the pre-treatment with ABA solution. 28 references, 5 figures, 1 table.

  19. Boron-rich oligomers for BNCT

    International Nuclear Information System (INIS)

    Gula, M.; Perleberg, O.; Gabel, D.

    2000-01-01

    The synthesis of two BSH derivatives is described, which can be used for oligomerization in DNA-synthesizers. Synthesis pathways lead to final products in five and six steps, respectively. Because of chirality interesting results were expected. NMR-measurements confirm this expectation. Possible oligomers with high concentrations of boron can be attached to biomolecules. These oligomers can be explored with several imaging methods (EELS, PEM) to determine the lower detection limit of boron with these methods. (author)

  20. Structural and electrical characterization of bamboo-shaped C–N nanotubes–poly ethylene oxide (PEO) composite films

    International Nuclear Information System (INIS)

    Yadav, Ram Manohar; Dobal, Pramod S.

    2012-01-01

    We have prepared bamboo-shaped C–N nanotubes–polyethylene oxide (PEO) composite films by solution cast technique and investigated their structural/microstructural and electrical properties and developed a correlation between them. The formation of clean compartmentalized bamboo-shaped C–N nanotubes was confirmed by TEM. SEM investigations revealed a homogeneous dispersion of nanotubes in PEO matrix. Enhanced electrical conductivity was observed for the C–N nanotubes–PEO composites than bare PEO. The conductivity measurements on the C–N nanotubes–PEO composite films with ∼20 wt % concentration of C–N nanotubes showed an increase of eight orders (∼7.5 × 10 −8 to 6.2 S cm −1 ) of magnitude in conductivity from bare PEO film. Raman spectra showed the stress-free nature of the composites and established the bonding of nanotubes with PEO, which resulted in the variation of Raman parameters. The Raman data of composites corroborate the findings of variation in electrical conductivity.

  1. Efficient removal of cobalt(II) and strontium(II) metals from water using ethylene diamine tetra-acetic acid functionalized graphene oxide

    Energy Technology Data Exchange (ETDEWEB)

    Amer, Hany; Moustafa, Wafaa M. [Nuclar Fuel Cycle Department, Nuclear and Radiological Regulatory Authority (NRRA), Naser City, Cairo (Egypt); Farghali, Ahmed A.; El Rouby, Waleed M.A. [Materials Science and Nanotechnology Department, Faculty of Postgraduate Studies for Advanced Sciences (PASA), Beni-Suef University (Egypt); Khalil, Waleed F. [Nuclar Fuel Cycle Department, Nuclear and Radiological Regulatory Authority (NRRA), Naser City, Cairo (Egypt); Materials Science and Nanotechnology Department, Faculty of Postgraduate Studies for Advanced Sciences (PASA), Beni-Suef University (Egypt)

    2017-12-04

    Graphene oxide (GO) with high specific surface area was prepared and functionalized with ethylene diamine tetra-acetic acid (EDTA). The as-prepared GO and the functionalized one (GO-EDTA) were characterized using high resolution transmission electron microscopy (HRTEM), Fourier transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD), and Raman spectroscopy. The as-prepared and EDTA functionalized GO were applied as adsorbent to remove strontium(II) and cobalt(II) from water. The results indicated that the prepared materials are efficient adsorbents for strontium(II) and cobalt(II) removal. The adsorption of Co{sup II} and Sr{sup II} under effects of contact time, temperature, and pH was investigated It is concluded that the maximum adsorption capacities of GO for Co{sup II} and Sr{sup II} were about 168 and 140 mg.g{sup -1}, whereas of GO-EDTA the values were about 197 and 158 mg.g{sup -1}, respectively. It is indicated that pH 6 and temperature 40 C are the best condition for Co{sup II} and Sr{sup II} removal from water. The application of Langmuir and Freundlich isotherms indicated that Langmuir isotherm is best fit for Co{sup II} and Sr{sup II} equilibrium adsorption. Adsorption kinetics were studied by applying pseudo first-order, pseudo second-order, and intraparticle diffusion models on the experimental data. The results proved that pseudo second-order model is the best represented adsorption kinetics. Appling the intraparticle diffusion regressions on the experimental data indicated that intraparticle diffusion involved in adsorption process, which was not the only rate-controlling step. (copyright 2017 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  2. Dynamics of poly(ethylene oxide) in a blend with poly(methyl methacrylate): A quasielastic neutron scattering and molecular dynamics simulations study

    International Nuclear Information System (INIS)

    Genix, A.-C.; Arbe, A.; Alvarez, F.; Colmenero, J.; Willner, L.; Richter, D.

    2005-01-01

    In this paper, we have addressed the question of the dynamic miscibility in a blend characterized by very different glass-transition temperatures, T g , for the components: poly(ethylene oxide) and poly(methyl methacrylate) (PEO/PMMA). The combination of quasielastic neutron scattering with isotopic labeling and fully atomistic molecular dynamics simulations has allowed us to selectively investigate the dynamics of the two components in the picosecond--10 nanoseconds scale at temperatures close and above the T g of the blend. The main focus was on the PEO component, i.e., that of the lowest T g , but first we have characterized the dynamics of the other component in the blend and of the pure PEO homopolymer as reference. In the region investigated, the dynamics of PMMA in the blend is strongly affected by the α-methyl rotation; an additional process detected in the experimental window 65 K above the blend-T g can be identified as the merged αβ process of this component that shows strong deviations from Gaussian behavior. On the other hand, pure PEO displays entropy driven dynamics up to very large momentum transfers. Such kind of motion seems to freeze when the PEO chains are in the blend. There, we have directly observed a very heterogeneous and moreover confined dynamics for the PEO component. The presence of the hardly moving PMMA matrix leads to the creation of little pockets of mobility where PEO can move. The characteristic size of such confined islands of mobility might be estimated to be of ≅1 nm. These findings are corroborated by the simulation study, which has been an essential support and guide in our data analysis procedure

  3. Highly CO2-Selective Gas Separation Membranes Based on Segmented Copolymers of Poly(Ethylene oxide) Reinforced with Pentiptycene-Containing Polyimide Hard Segments.

    Science.gov (United States)

    Luo, Shuangjiang; Stevens, Kevin A; Park, Jae Sung; Moon, Joshua D; Liu, Qiang; Freeman, Benny D; Guo, Ruilan

    2016-01-27

    Poly(ethylene oxide) (PEO)-containing polymer membranes are attractive for CO2-related gas separations due to their high selectivity toward CO2. However, the development of PEO-rich membranes is frequently challenged by weak mechanical properties and a high crystallization tendency of PEO that hinders gas transport. Here we report a new series of highly CO2-selective, amorphous PEO-containing segmented copolymers prepared from commercial Jeffamine polyetheramines and pentiptycene-based polyimide. The copolymers are much more mechanically robust than the nonpentiptycene containing counterparts due to the molecular reinforcement mechanism of supramolecular chain threading and interlocking interactions induced by the pentiptycene structures, which also effectively suppresses PEO crystallization leading to a completely amorphous structure even at 60% PEO weight content. Membrane transport properties are sensitively affected by both PEO weight content and PEO chain length. A nonlinear correlation between CO2 permeability with PEO weight content was observed due to the competition between solubility and diffusivity contributions, whereby the copolymers change from being size-selective to solubility-selective when PEO content reaches 40%. CO2 selectivities over H2 and N2 increase monotonically with both PEO content and chain length, indicating strong CO2-philicity of the copolymers. The copolymer film with the longest PEO sequence (PEO2000) and highest PEO weight content (60%) showed a measured CO2 pure gas permeability of 39 Barrer, and ideal CO2/H2 and CO2/N2 selectivities of 4.1 and 46, respectively, at 35 °C and 3 atm, making them attractive for hydrogen purification and carbon capture.

  4. The release characteristics of a model protein from self-assembled succinimide-terminated poly(lactide-co-glycolide ethylene oxide fumarate) nanoparticles

    Energy Technology Data Exchange (ETDEWEB)

    Mercado, Angel E; He Xuezhong; Xu Weijie; Jabbari, Esmaiel [Biomimetic Materials and Tissue Engineering Laboratories, Department of Chemical Engineering, University of South Carolina, SC 29208, Columbia (United States)], E-mail: jabbari@engr.sc.edu

    2008-08-13

    Lactide-co-glycolide-based functionalized nanoparticles (NPs), because of their high surface areas for conjugation and biodegradability, are attractive as carriers for stabilization and sustained delivery of therapeutic agents and protein drugs. The objective of this work was to compare the release characteristics of model molecules encapsulated in NPs produced from poly(lactide-co-glycolide fumarate) (PLGF) macromer with those of model molecules conjugated to NPs produced from succinimide (NHS)-terminated PLGF-NHS macromer. Poly(lactide fumarate) (PLAF), PLGF and poly(lactide-co-ethylene oxide fumarate) (PLEOF) macromers were synthesized by condensation polymerization. The hydroxyl end-groups of PLAF and PLGF macromers were reacted with N,N{sup '}-disuccinimidyl carbonate (DSC) to produce succinimide-terminated PLAF-NHS and PLGF-NHS macromers. The macromers were self-assembled by dialysis to form NPs. The amphiphilic PLEOF macromer was used as the surfactant to stabilize the NPs in the process of self-assembly. 1-(2-pyridylazo)-2-naphthol (PAN) was used as a model small molecule for encapsulation in PLAF or PLGF NPs and bovine serum albumin (BSA) was used as a model protein for conjugation to PLAF-NHS and PLGF-NHS NPs. The profile of release of the encapsulated PAN from PLAF and PLGF NPs was non-linear and consisted of a burst release followed by a period of sustained release. The release profile for BSA, conjugated to PLAF-NHS and PLGF-NHS NPs, was linear up to complete degradation of the NPs. PLGF and PLAF NPs degraded in 15 and 28 days, respectively, while PLGF-NHS and PLAF-NHS NPs degraded in 25 and 38 days, which demonstrated that the release was dominated by erosion of the matrix. PLAF-NHS and PLGF-NHS NPs are potentially useful as carriers for sustained in situ release of protein drugs.

  5. Conformational sensitivity of conjugated poly(ethylene oxide)-poly(amidoamine) molecules to cations adducted upon electrospray ionization – A mass spectrometry, ion mobility and molecular modeling study

    Energy Technology Data Exchange (ETDEWEB)

    Tintaru, Aura [Aix-Marseille Université – CNRS, UMR 7273, Institut de Chimie Radicalaire, Marseille (France); Chendo, Christophe [Aix-Marseille Université – CNRS, FR 1739, Fédération des Sciences Chimiques de Marseille, Spectropole, Marseille (France); Wang, Qi [Aix-Marseille Université – CNRS, UMR 6114, Centre Interdisciplinaire de Nanosciences de Marseille, Marseille (France); Viel, Stéphane [Aix-Marseille Université – CNRS, UMR 7273, Institut de Chimie Radicalaire, Marseille (France); Quéléver, Gilles; Peng, Ling [Aix-Marseille Université – CNRS, UMR 6114, Centre Interdisciplinaire de Nanosciences de Marseille, Marseille (France); Posocco, Paola [University of Trieste, Molecular Simulation Engineering (MOSE) Laboratory, Department of Engineering and Architecture (DEA), Trieste (Italy); National Interuniversity Consortium for Material Science and Technology (INSTM), Research Unit MOSE-DEA, University of Trieste, Trieste (Italy); Pricl, Sabrina, E-mail: sabrina.pricl@di3.units.it [University of Trieste, Molecular Simulation Engineering (MOSE) Laboratory, Department of Engineering and Architecture (DEA), Trieste (Italy); National Interuniversity Consortium for Material Science and Technology (INSTM), Research Unit MOSE-DEA, University of Trieste, Trieste (Italy); Charles, Laurence, E-mail: laurence.charles@univ-amu.fr [Aix-Marseille Université – CNRS, UMR 7273, Institut de Chimie Radicalaire, Marseille (France)

    2014-01-15

    Graphical abstract: -- Highlights: •ESI-MS/MS, IMS and molecular modeling were combined to study PEO-PAMAM conformation. •Protonated and lithiated molecules were studied, with charge states from 2 to 4. •Protonation mostly occurred on PAMAM, with PEO units enclosing the protonated group. •Lithium adduction on PEO units lead to more expanded conformations. •Charge location strongly influenced PEO-PAMAM dissociation behavior. -- Abstract: Tandem mass spectrometry and ion mobility spectrometry experiments were performed on multiply charged molecules formed upon conjugation of a poly(amidoamine) (PAMAM) dendrimer with a poly(ethylene oxide) (PEO) linear polymer to evidence any conformational modification as a function of their charge state (2+ to 4+) and of the adducted cation (H{sup +}vs Li{sup +}). Experimental findings were rationalized by molecular dynamics simulations. The G0 PAMAM head-group could accommodate up to three protons, with protonated terminal amine group enclosed in a pseudo 18-crown-6 ring formed by the PEO segment. This particular conformation enabled a hydrogen bond network which allowed long-range proton transfer to occur during collisionally activated dissociation. In contrast, lithium adduction was found to mainly occur onto oxygen atoms of the polyether, each Li{sup +} cation being coordinated by a 12-crown-4 pseudo structure. As a result, for the studied polymeric segment (M{sub n} = 1500 g mol{sup −1}), PEO-PAMAM hybrid molecules exhibited a more expanded shape when adducted to lithium as compared to proton.

  6. Novel self-associating poly(ethylene oxide)-b-poly(epsilon-caprolactone) based drug conjugates and nano-containers for paclitaxel delivery.

    Science.gov (United States)

    Shahin, Mostafa; Lavasanifar, Afsaneh

    2010-04-15

    Poly(ethylene oxide)-block-poly(epsilon-caprolactone) (PEO-b-PCL) copolymers bearing paclitaxel (PTX) side groups on PCL (PEO-b-P(CL-PTX) were synthesized and assembled to particles of 123 nm average diameter. At 20% (w/w) PTX to polymer conjugation, PEO-b-P(CL-PTX) demonstrated only 5.0 and 6.7% PTX release after 72 h incubation at pH 7.4 and 5.0, respectively, but revealed signs of chain cleavage at pH 5.0. The cytotoxicity of PEO-b-P(CL-PTX) against MDA-MB-435 cancer cells increased as incubation time was raised from 72 to 96 h (IC(50) of 680 and 475 ng/mL, respectively), but it was still significantly lower than the cytotoxicity of free PTX (IC(50) of 3.5 ng/mL at 72 h). In further studies, micelles of PEO-b-PCL and those bearing benzyl or PTX on PCL were used for physical encapsulation of PTX, where maximum level of loading was achieved by PEO-b-P(CL-PTX) (2.22%, w/w). The release of PTX from this carrier was rapid; however. The in vitro cytotoxicity of physically loaded PTX was independent of carrier and similar to that of free PTX. This was attributed to the low concentration of polymers which fell below their critical micellar concentration in the cytotoxicity study. The results point to the potential of chemically tailored PEO-b-PCL for optimum PTX solubilization and delivery. Copyright 2010 Elsevier B.V. All rights reserved.

  7. In situ immobilization of proteins and RGD peptide on polyurethane surfaces via poly(ethylene oxide) coupling polymers for human endothelial cell growth.

    Science.gov (United States)

    Wang, Dong-an; Ji, Jian; Sun, Yong-hong; Shen, Jia-cong; Feng, Lin-xian; Elisseeff, Jennifer H

    2002-01-01

    A "CBABC"-type pentablock coupling polymer, mesylMPEO, was designed and synthesized to promote human endothelial cell growth on the surfaces of polyurethane biomaterials. The polymer was composed of a central 4,4'-methylenediphenyl diisocyanate (MDI) coupling unit and poly(ethylene oxide) (PEO) spacer arms with methanesulfonyl (mesyl) end groups pendent on both ends. As the presurface modifying additive (pre-SMA), the mesylMPEO was noncovalently introduced onto the poly(ether urethane) (PEU) surfaces by dip coating, upon which the protein/peptide factors (gelatin, albumin, and arginine-glycine-aspartic acid tripeptide [RGD]) were covalently immobilized in situ by cleavage of the original mesyl end groups. The pre-SMA synthesis and PEU surface modification were characterized using nuclear magnetic resonance spectroscopy ((1)H NMR), attenuated total reflection infrared spectroscopy (ATR-FTIR), and X-ray photoelectron spectroscopy (XPS). Human umbilical vein endothelial cells (HUVEC) were harvested manually by collagenase digestion and seeded on the modified PEU surfaces. Cell adhesion ratios (CAR) and cell proliferation ratios (CPR) were measured using flow cytometry, and the individual cell viability (ICV) was determined by MTT assay. The cell morphologies were investigated by optical inverted microscopy (OIM) and scanning electrical microscopy (SEM). The gelatin- and RGD-modified surfaces were HUVEC-compatible and promoted HUVEC growth. The albumin-modified surfaces were compatible but inhibited cell adhesion. The results also indicated that, for HUVEC in vitro cultivation, the cell adhesion stage was of particular importance and had a significant impact on the cell responses to the modified surfaces.

  8. Single-Molecule Tracking Study of the Permeability and Transverse Width of Individual Cylindrical Microdomains in Solvent-Swollen Polystyrene-block-poly(ethylene oxide) Films.

    Science.gov (United States)

    Sapkota, Dol Raj; Tran-Ba, Khanh-Hoa; Elwell-Cuddy, Trevor; Higgins, Daniel A; Ito, Takashi

    2016-12-01

    Understanding the properties of solvent-swollen block copolymer (BCP) microdomains is important for better solvent-based control of microdomain morphology, orientation, and permeability. In this study, single-molecule tracking (SMT) was explored to assess the permeability and transverse width of individual cylindrical microdomains in solvent-swollen polystyrene-block-poly(ethylene oxide) (PS-b-PEO) films. PS-b-PEO films comprising shear-elongated cylindrical PEO microdomains were prepared by sandwiching its benzene or tetrahydrofuran (THF) solution between two glass substrates. SMT measurements were performed at different drying times to investigate the effects of solvent evaporation on the microdomain properties. SMT data showed one-dimensional (1D) motions of single fluorescent molecules (sulforhodamine B) based on their diffusion within the cylindrical microdomains. Microdomain permeability and transverse width were assessed from the single-molecule diffusion coefficients (D SMT ) and transverse variance of the 1D trajectories (σ δ 2 ), respectively. The D SMT and σ δ 2 values from individual 1D trajectories were widely distributed with no evidence of correlation on a single molecule basis, possibly because the individual microdomains in a film were swollen to different extents. On average, microdomain permeability (D) and effective radius (r) gradually decreased within the first 3 days of drying due to solvent evaporation, and changed negligibly thereafter. PS-b-PEO films prepared from THF solutions exhibited larger changes in D and r as compared with those from benzene solutions due to the better swelling of the PEO microdomains by THF. Importantly, changes in D were more prominent than those in r, suggesting that the permeability of the PEO microdomains is very susceptible to the presence of solvent. These results reveal the unique capability of SMT to assess the properties of individual cylindrical microdomains in a solvent-swollen BCP film.

  9. Regulating drug release from pH- and temperature-responsive electrospun CTS-g-PNIPAAm/poly(ethylene oxide) hydrogel nanofibers

    International Nuclear Information System (INIS)

    Yuan, Huihua; Li, Biyun; Liang, Kai; Lou, Xiangxin; Zhang, Yanzhong

    2014-01-01

    Temperature- and pH-responsive polymers have been widely investigated as smart drug release systems. However, dual-sensitive polymers in the form of nanofibers, which is advantageous in achieving rapid transfer of stimulus to the smart polymeric structures for regulating drug release behavior, have rarely been explored. In this study, chitosan-graft-poly(N-isopropylacrylamide) (CTS-g-PNIPAAm) copolymer was synthesized by using 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide (EDC) and N-hydroxy succinimide (NHS) as grafting agents to graft carboxyl-terminated PNIPAAm (PNIPAAm-COOH) chains onto the CTS biomacromolecules, and then CTS-g-PNIPAAm with or without bovine serum albumin (BSA) was fabricated into nanofibers through electrospinning using poly(ethylene oxide) (PEO, 10 wt%) as a fiber-forming facilitating additive. The BSA laden CTS-g-PNIPAAm/PEO hydrogel nanofibers were tested to determine their drug release profiles by varying pH and temperature. Finally, cytotoxicity of the CTS-g-PNIPAAm/PEO hydrogel nanofibers was evaluated by assaying the L929 cell proliferation using the MTT method. It was found that the synthesized CTS-g-PNIPAAm possessed a temperature-induced phase transition and lower critical solution temperature (LCST) at 32° C in aqueous solutions. The rate of BSA release could be well modulated by altering the environmental pH and temperature of the hydrogel nanofibers. The CTS-g-PNIPAAm/PEO hydrogel nanofibers supported L929 cell growth, indicative of appropriate cytocompatibility. Our current work could pave the way towards developing multi-stimuli responsive nanofibrous smart materials for potential applications in the fields of drug delivery and tissue engineering. (paper)

  10. Toxicity evaluation of methoxy poly(ethylene oxide)-block-poly(ε-caprolactone) polymeric micelles following multiple oral and intraperitoneal administration to rats.

    Science.gov (United States)

    Binkhathlan, Ziyad; Qamar, Wajhul; Ali, Raisuddin; Kfoury, Hala; Alghonaim, Mohammed

    2017-09-01

    Methoxy poly(ethylene oxide)- block -poly(ɛ-caprolactone) (PEO- b -PCL) copolymers are amphiphilic and biodegradable copolymers designed to deliver a variety of drugs and diagnostic agents. The aim of this study was to synthesize PEO- b -PCL block copolymers and assess the toxic effects of drug-free PEO- b -PCL micelles after multiple-dose administrations via oral or intraperitoneal (ip) administration in rats. Assembly of block copolymers was achieved by co-solvent evaporation method. To investigate the toxicity profile of PEO- b -PCL micelles, sixty animals were divided into two major groups: The first group received PEO- b -PCL micelles (100 mg/kg) by oral gavage daily for seven days, while the other group received the same dose of micelles by ip injections daily for seven days. Twenty-four hours following the last dose, half of the animals from each group were sacrificed and blood and organs (lung, liver, kidneys, heart and spleen) were collected. Remaining animals were observed for further 14 days and was sacrificed at the end of the third week, and blood and organs were collected. None of the polymeric micelles administered caused any significant effects on relative organ weight, animal body weight, leucocytes count, % lymphocytes, liver and kidney toxicity markers and organs histology. Although the dose of copolymers used in this study is much higher than those used for drug delivery, it did not cause any significant toxic effects in rats. Histological examination of all the organs confirmed the nontoxic nature of the micelles.

  11. Toxicity evaluation of methoxy poly(ethylene oxide-block-poly(ε-caprolactone polymeric micelles following multiple oral and intraperitoneal administration to rats

    Directory of Open Access Journals (Sweden)

    Ziyad Binkhathlan

    2017-09-01

    Full Text Available Methoxy poly(ethylene oxide-block-poly(ɛ-caprolactone (PEO-b-PCL copolymers are amphiphilic and biodegradable copolymers designed to deliver a variety of drugs and diagnostic agents. The aim of this study was to synthesize PEO-b-PCL block copolymers and assess the toxic effects of drug-free PEO-b-PCL micelles after multiple-dose administrations via oral or intraperitoneal (ip administration in rats. Assembly of block copolymers was achieved by co-solvent evaporation method. To investigate the toxicity profile of PEO-b-PCL micelles, sixty animals were divided into two major groups: The first group received PEO-b-PCL micelles (100 mg/kg by oral gavage daily for seven days, while the other group received the same dose of micelles by ip injections daily for seven days. Twenty-four hours following the last dose, half of the animals from each group were sacrificed and blood and organs (lung, liver, kidneys, heart and spleen were collected. Remaining animals were observed for further 14 days and was sacrificed at the end of the third week, and blood and organs were collected. None of the polymeric micelles administered caused any significant effects on relative organ weight, animal body weight, leucocytes count, % lymphocytes, liver and kidney toxicity markers and organs histology. Although the dose of copolymers used in this study is much higher than those used for drug delivery, it did not cause any significant toxic effects in rats. Histological examination of all the organs confirmed the nontoxic nature of the micelles.

  12. Haemoglobin adducts of acrylonitrile and ethylene oxide in acrylonitrile workers, dependent on polymorphisms of the glutathione transferases GSTT1 and GSTM1.

    Science.gov (United States)

    Thier, R; Lewalter, J; Kempkes, M; Selinski, S; Brüning, T; Bolt, H M

    1999-01-01

    Fifty-nine persons with industrial handling of low levels of acrylonitrile (AN) were studied. As part of a medical surveillance programme an extended haemoglobin adduct monitoring [N-(cyanoethyl)valine, CEV; N-(methyl)valine. MV: N-(hydroxyethyl)valine, HEV] was performed. Moreover, the genetic states of the polymorphic glutathione transferases GSTM1 and GSTT1 were assayed by polymerase chain reaction (PCR). Repetitive analyses of CEV and MV in subsequent years resulted in comparable values (means, 59.8 and 70.3 microg CEV/1 blood; 6.7 and 6.7 microg MV/1 blood). Hence, the industrial AN exposures were well below current official standards. Monitoring the haemoglobin adduct CEV appears as a suitable means of biomonitoring and medical surveillance under such exposure conditions. There was also no apparent correlation between the CEV and HEV or CEV and MV adduct levels. The MV and HEV values observed represented background levels, which apparently are not related to any occupational chemical exposure. There was no consistent effect of the genetic GSTM1 or GSTT1 state on CEV adduct levels induced by acrylonitrile exposure. Therefore, neither GSTM1 nor GSTT1 appears as a major AN metabolizing isoenzyme in humans. The low and physiological background levels of MV were also not influenced by the genetic GSTM1 state, but the MV adduct levels tended to be higher in GSTT1- individuals compared to GSTT1 + persons. With respect to the background levels of HEV adducts observed, there was no major influence of the GSTM1 state, but GST- individuals displayed adduct levels that were about 1/3 higher than those of GSTT1 + individuals. The coincidence with known differences in rates of background sister chromatid exchange between GSTT1- and GSTT1 + persons suggests that the lower ethylene oxide (EO) detoxification rate in GSTT1- persons, indicated by elevated blood protein hydroxyethyl adduct levels, leads to an increased genotoxic effect of the physiological EO background.

  13. Identification of Colored Dyes that are Resistant to Fading on Exposure to Ethylene Oxide; Use with Indicating FTA™ Sample Collection Cards

    Directory of Open Access Journals (Sweden)

    Nina Moran

    2016-01-01

    Full Text Available Regulatory Standards and Forensic Communities are expressing an expectation for HID products to be certified as “DNA-free.” Recently, “DNA-free” status was described for HID-related products using ethylene oxide (EtO; this gas reduces the presence of amplifiable DNA and causes minimal interference to downstream HID-analytical methods. During sample collection, indicating cards, for example, Indicating FTA™ (GE Healthcare Life Sciences, UK, are used to collect and store buccal cell DNA. These cards contain a dye which changes color on application of a colorless sample. Generating “DNA-free” indicating cards using EtO should not impact the dyes' ability to indicate sample location or the efficacy of the card in downstream HID-analytical methods. This study was initiated to identify alternative dyes to those currently used with sample indicating collection cards. The most promising, dyes when applied to cellulose papers exhibited a uniform color distribution and excellent sample indicating properties even when mixed with chemicals associated with FTA™. When dyed cellulose papers were exposed to EtO, ultraviolet radiation, elevated temperature, and humidity, negligible fading or discoloration was observed. The presence of these dyes on cellulose papers did not interfere with direct short tandem repeat (STR profiling. Allelic concordance, first pass success rate, and mean peak heights were comparable to samples applied to Indicating FTA. Biological samples applied to EtO-treated dyed cellulose papers and stored >1 month produced full STR profiles of sufficient quality to allow submission to DNA databases, confirming negligible interference from EtO treatment. These alternative sample indicating dyes resist EtO-mediated fading while fulfilling the Forensic Community's expectation for “DNA-free” with negligible impact on collection card performance.

  14. 40 CFR 721.3800 - Formaldehyde, condensated polyoxyethylene fatty acid, ester with styrenated phenol, ethylene...

    Science.gov (United States)

    2010-07-01

    ... polyoxyethylene fatty acid, ester with styrenated phenol, ethylene oxide adduct. 721.3800 Section 721.3800... Formaldehyde, condensated polyoxyethylene fatty acid, ester with styrenated phenol, ethylene oxide adduct. (a... generically as formaldehyde, condensated polyoxyethylene fatty acid, ester with styrenated phenol, ethylene...

  15. Manufacturing of multilayer graphene oxide/poly(ethylene terephthalate) nanocomposites with tunable crystallinity, chain orientations and thermal transitions

    Energy Technology Data Exchange (ETDEWEB)

    Seyyed Monfared Zanjani, Jamal [Faculty of Engineering and Natural Sciences, Sabanci University, Orhanli, 34956 Tuzla, Istanbul (Turkey); Saner Okan, Burcu, E-mail: bsanerokan@sabanciuniv.edu [Sabanci University Nanotechnology Research and Application Center, SUNUM, Orhanli, 34956 Tuzla, Istanbul (Turkey); Nanografen Nanotechnological Products Limited Company, GOSB Teknopark, Gebze 41430, Kocaeli (Turkey); Menceloglu, Yusuf [Faculty of Engineering and Natural Sciences, Sabanci University, Orhanli, 34956 Tuzla, Istanbul (Turkey); Nanografen Nanotechnological Products Limited Company, GOSB Teknopark, Gebze 41430, Kocaeli (Turkey)

    2016-06-15

    Thermally exfoliated graphene oxide (TEGO) reinforced polyethylene terephthalate (PET) nanocomposites with controlled crystallinity, chain conformations and thermo-mechanical properties were produced with very low TEGO weight fractions by a twin-screw compounding extruder. Tensile modulus was found to increase by 52% by the addition of 1 wt% TEGO. This significant increase in mechanical properties of PET nanocomposites was explained by well intercalation of PET chains through multi-layer graphene sheets and complete coverage of graphene surface by electrostatic interactions. An increase in the ratio of gauche and trans conformations in PET chains indicated that PET nanocomposites became more crystalline by increasing TEGO amount. Transmission electron microscopy observations showed the favorable interaction between TEGO sheets and PET matrix facilitating the dispersion and flattening of graphene sheets into polymeric matrix during elongation. The integration of 1 wt% TEGO sheets into PET matrix enhanced heat distortion temperature from 71 °C for neat specimen upto 91.6 °C at the constant stress of 0.45 MPa, and increased Vicat softening point from 76 °C upto 95 °C. Therefore, the failures of PET considerably reduced by improving short-term heat resistance and its softening properties between glass transition temperature and melting temperature by the incorporation of TEGO sheets. - Highlights: • 52% modulus improvement by the addition of 1 wt% graphene in PET. • Well-intercalation of PET chains through graphene sheets during compounding process. • Homogeneous graphene dispersion by favorable interactions between graphene and PET. • Enhancement in Heat distortion temperature and Vicat softening point of PET composite. • Considerable reduction in failures of PET by improving short-term heat resistance.

  16. Electron beam curing of acrylic oligomers

    International Nuclear Information System (INIS)

    Seto, J.; Arakawa, S.; Ishimoto, C.; Miyashita, M.; Nagai, T.; Noguchi, T.; Shibata, A.

    1984-01-01

    The electron-beam curing process of acrylic oligomers, with and without γ-Fe 2 O 3 pigment filler and blended linear polymer, was investigated in terms of molecular structure and reaction mechanism. The polymerized fraction of trimethylolpropane-triacrylate (TMPTA) oligomers increases with increasing total dose, and is independent of the dose rate. Since the reaction rate is linearly dependent on the dose rate, the reaction mechanism involves monomolecular termination. The reaction rate does not depend on the number of functional groups of the oligomer at low doses, but above 0.3 Mrad the rate is slower for oligomers of higher functionality. A gel is formed more readily upon curing of a polyfunctional than a monofunctional oligomer, especially at high conversion to polymer; the resulting loss of flexibility of the polymer chains slows the reaction. Decrease of the molecular weight per functional group results in lower conversion; this is also due to the loss of chain flexibility, which is indicated as well by a higher glass-transition temperature. Modification of the acrylate oligomers with urethane results in more effective cross-linking reactions because of the more rigid molecular chains. Addition of γ-Fe 2 O 3 pigment reduces the reaction rate very little, but has the effect of providing added structural integrity, as indicated by the decrease of solvent-extractable material and the improvement of anti-abrasion properties. However, the flexibility of the coating and its adhesion to a PET base film are diminished. To increase the flexibility, linear polyvinylchloride and/or polyurethane were added to the acrylic oligomers. Final conversion to polymer was nearly 100 percent, and a higher elastic modulus and better antiabrasion properties were realized

  17. Unimolecular fragrmentations of the radical cation of the high-valent organometal oxide CH3ReO3 and its reactivity with ethylene in the gas phase

    Science.gov (United States)

    Schröder, Detlef; Herrmann, W. A.; Fischer, Richard W.; Schwarz, Helmut

    1992-12-01

    The unimolecular chemistry of CH3ReO[radical sign]+3 in the gas phase commences with a methyl migration to' generate CH3 OReO[radical sign]+2. This further undergoes multiple hydrogen migration to the metal centre to generate an intermediate which serves as a precursor for the elimination of both molecular hydrogen and of carbon monoxide. If CH3ReO[radical sign]+3 is reacted with ethylene, inter alia products are observed which point to a competition between an intramolecular metathesis reaction of the ethylene-inserted intermediate CH3CH2CH2ReO3[radical sign]+ and epoxidation of ethylene to generate c-C2H4O.

  18. Applications of oligomers for nanostructured conducting polymers.

    Science.gov (United States)

    Wang, Yue; Tran, Henry D; Kaner, Richard B

    2011-01-03

    This Feature Article provides an overview of the distinctive nanostructures that aniline oligomers form and the applications of these oligomers for shaping the nanoscale morphologies and chirality of conducting polymers. We focus on the synthetic methods for achieving such goals and highlight the underlying mechanisms. The clear advantages of each method and their possible drawbacks are discussed. Assembly and applications of these novel organic (semi)conducting nanomaterials are also outlined. We conclude this article with our perspective on the main challenges, new opportunities, and future directions for this nascent yet vibrant field of research. Copyright © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  19. In-situ preparation of poly(ethylene oxide)/Li3PS4 hybrid polymer electrolyte with good nanofiller distribution for rechargeable solid-state lithium batteries

    Science.gov (United States)

    Chen, Shaojie; Wang, Junye; Zhang, Zhihua; Wu, Linbin; Yao, Lili; Wei, Zhenyao; Deng, Yonghong; Xie, Dongjiu; Yao, Xiayin; Xu, Xiaoxiong

    2018-05-01

    Nano-sized fillers in a polymer matrix with good distribution can play a positive role in improving polymer electrolytes in the aspects of ionic conductivity, mechanical property and electrochemical performance of Li-ion cells. Herein, polyethylene oxide (PEO)/Li3PS4 hybrid polymer electrolyte is prepared via a new in-situ approach. The ionic conductivities of the novel hybrid electrolytes with variable proportions are measured, and the optimal electrolyte of PEO-2%vol Li3PS4 presents a considerable ionic conductivity of 8.01 × 10-4 S cm-1 at 60 °C and an electrochemical window up to 5.1 V. The tests of DSC and EDXS reveal that the Li3PS4 nanoparticles with better distribution, as active fillers scattering in the PEO, exhibit a positive effect on the transference of lithium ion and electrochemical interfacial stabilities. Finally, the assembled solid-state LiFePO4/Li battery presents a decent cycling performance (80.9% retention rate after 325 cycles at 60 °C) and excellent rate capacities with 153, 143, 139 and 127 mAh g-1 at the discharging rate of 0.1 C, 0.2 C, 0.5 C and 1 C at 60 °C. It is fully proved that it is an advanced strategy to preparing the new organic/inorganic hybrid electrolytes for lithium-ion batteries applications.

  20. Simultaneous determination of mercapturic acids derived from ethylene oxide (HEMA), propylene oxide (2-HPMA), acrolein (3-HPMA), acrylamide (AAMA) and N,N-dimethylformamide (AMCC) in human urine using liquid chromatography/tandem mass spectrometry.

    Science.gov (United States)

    Schettgen, Thomas; Musiol, Anita; Kraus, Thomas

    2008-09-01

    Mercapturic acids are highly important and specific biomarkers of exposure to carcinogenic substances in occupational and environmental medicine. We have developed and validated a reliable, specific and very sensitive method for the simultaneous determination of five mercapturic acids derived from several high-production chemicals used in industry, namely ethylene oxide, propylene oxide, acrylamide, acrolein and N,N-dimethylformamide. Analytes are enriched and cleaned up from urinary matrix by offline solid-phase extraction. The mercapturic acids are subsequently separated by means of high-performance liquid chromatography on a Luna C8 (2) column and specifically quantified by tandem mass spectrometric detection using isotopically labelled analytes as internal standards. The limits of detection (LODs) for N-acetyl-S-2-carbamoylethylcysteine (AAMA) and N-acetyl-S-2-hydroxyethylcysteine (HEMA) were 2.5 microg/L and 0.5 microg/L urine, while for N-acetyl-S-3-hydroxypropylcysteine (3-HPMA), N-acetyl-S-2-hydroxypropylcysteine (2-HPMA) and N-acetyl-S-(N-methylcarbamoyl)cysteine (AMCC) it was 5 microg/L. These LODs were sufficient to detect the background exposure of the general population. We applied the method on spot urine samples of 28 subjects of the general population with no known occupational exposure to these substances. Median levels for AAMA, HEMA, 3-HPMA, 2-HPMA and AMCC in non-smokers (n = 14) were 52.6, 2.0, 155, 7.1 and 113.6 microg/L, respectively. In smokers (n = 14), median levels for AAMA, HEMA, 3-HPMA, 2-HPMA and AMCC were 243, 5.3, 1681, 41.7 and 822 microg/L, respectively. Due to the simultaneous quantification of these mercapturic acids, our method is well suited for the screening of workers with multiple chemical exposures as well as the determination of the background excretion of the general population.

  1. Electrografting of conductive oligomers and polymers using diazonium electroreduction

    International Nuclear Information System (INIS)

    Lacroix, Jean Christophe; Trippe-Allard, Gaelle; Ghilane, Jalal; Martin, Pascal

    2014-01-01

    This paper describes the attachment of conjugated oligomers onto electrode surface through the reduction of diazonium compounds. In this connection some properties of conjugated oligomers and of layers grafted through diazonium electroreduction will first be briefly presented. The electrochemical behavior of conjugated oligomers grafted on a surface using diazonium electroreduction will then be discussed. (paper)

  2. Electrografting of conductive oligomers and polymers using diazonium electroreduction

    Science.gov (United States)

    Lacroix, Jean Christophe; Trippe-Allard, Gaelle; Ghilane, Jalal; Martin, Pascal

    2014-03-01

    This paper describes the attachment of conjugated oligomers onto electrode surface through the reduction of diazonium compounds. In this connection some properties of conjugated oligomers and of layers grafted through diazonium electroreduction will first be briefly presented. The electrochemical behavior of conjugated oligomers grafted on a surface using diazonium electroreduction will then be discussed.

  3. Synthesis and characterization of thermally stable oligomer-metal ...

    African Journals Online (AJOL)

    The thermal stabilities of the oligomer-metal complexes were compared by thermogravimetric (TG) and differential thermal (DTA) analyses. According to TG, oligomer-metal complexes were stable against to temperature and thermooxidative decomposition. The weight losses of oligomer-metal complexes were found to be 5 ...

  4. Nickel-catalyzed reactions of enone with ethylene

    International Nuclear Information System (INIS)

    Nishimura, A; Haba, T; Ohashi, M; Ogoshi, S

    2010-01-01

    The reaction of (E)-1-phenylbut-2-en-1-one with ethylene in the presence of a catalytic amount of Ni(cod) 2 and PCy 3 at room temperature gave two kinds of three-component addition products; one is 1,6-enone composed of an enone and two ethylene molecules, and the other is 1,5-diketone composed of two enones and an ethylene. The reactions might proceed via oxidative cyclization of an enone and an ethylene with nickel(0).

  5. Preparation of liquid-core nanocapsules from poly[(ethylene oxide)-co-glycidol] with multiple hydrophobic linoleates at an oil-water interface and its encapsulation of pyrene.

    Science.gov (United States)

    Ren, Yong; Wang, Guowei; Huang, Junlian

    2007-06-01

    A convenient approach is provided to prepare liquid-core nanocapsules by cross-linking an amphiphilic copolymer at an oil-water interface. The hydrophilic copolymer poly[(ethylene oxide)-co-glycidol] was prepared by anionic polymerization of ethylene oxide and ethoxyethyl glycidyl ether first, then the hydroxyl groups on the backbone were recovered after hydrolysis and partly modified by hydrophobic conjugated linoleic acid. The copolymer with multiple linoleate pendants was absorbed at an oil-water interface and then cross-linked to form stable nanocapsules. The mean diameter of the nanocapsule was below 350 nm, and the size distribution was relatively narrow (<0.2) at low concentrations of oil in acetone (<10 mg/mL). The particle size could be tuned easily by variation of the emulsification conditions. The nanocapsule was stable in water for at least 5 months, and the shell maintained its integrity after removal of the oily core by solvent. Pyrene was encapsulated in these nanocapsules, and a loading efficiency as high as 94% was measured by UV spectroscopy.

  6. First detection of lamella-gyroid-cylinder phase transition of neat polyethylene-poly(ethylene oxide) diblock copolymers on the basis of synchrotron WAXD/SAXS and infrared/Raman spectral measurements

    International Nuclear Information System (INIS)

    Weiyu, Cao; Tashiro, Kohji; Hanesaka, Makoto; Takeda, Shinichi; Masunaga, Hiroyasu; Sasaki, Sono; Takata, Masaki

    2009-01-01

    The phase transition behaviour of polyethylene-b-poly(ethylene oxide) (PE-b-PEO) diblock copolymer with relatively short chain lengths has been studied on the basis of temperature dependent infrared and Raman spectral measurements and synchrotron WAXD/SAXS simultaneous measurements, from which the concrete structural changes were deduced successfully from the various levels of molecular chain conformation, chain packing mode and higher-order structure. The higher-order structure has been found to transform between lamella, perforated lamella, gyroid, cylinder and sphere structures. The inner structural changes occurring in the polyethylene and poly(ethylene oxide) parts have been related with these morphological changes. The morphological transition from lamella to gyroid occurs with keeping the crystalline state of polyethylene parts. This apparently curious transition can be interpreted reasonably by assuming the thermally-activated chain motion in the crystal lattice, which may play an important role as a trigger to induce the morphological change from lamella to gyroid. This idea was supported by the measurement of half-width of Raman anti-symmetric CH 2 stretching band sensitive to the thermal mobility of alkyl chains.

  7. Peptide oligomers for holographic data storage

    DEFF Research Database (Denmark)

    Berg, Rolf Henrik; Hvilsted, Søren; Ramanujam, P.S.

    1996-01-01

    SEVERAL classes of organic materials (such as photoanisotropic liquid-crystalline polymers(1-4) and photorefractive polymers(5-7)) are being investigated for the development of media for optical data storage. Here we describe a new family of organic materials-peptide oligomers containing azobenzene...

  8. Preparation of pH-sensitive poly(ethylene oxide) hydrogels grafted by γ-ray irradiation and their applications for drug delivery system

    International Nuclear Information System (INIS)

    Nho, Y.-C.; Kang, P.-H.; Lim, Y.-M.; Kuk, I.-H.

    2006-01-01

    undesirable. Oral delivery of peptides, proteins and other drugs to the gastrointestinal (GI) tract is one of the most challenging issues, and thus, under much investigation. There are many hurdles, including protein inactivation by digestive enzymes in the GI tract, and the poor epithelial permeability of these drugs. Certain hydrogels may overcome some of these problems by appropriate molecular design or formulation approaches. In this study, pH-sensitive hydrogels were studied as a drug carrier for the protection of insulin from the acidic environment of the stomach before releasing it in the small intestine. Hydrogels based on poly(ethylene oxide) (PEO) networks grafted with methacrylic acid (MAA) or acrylic acid (AAc) were prepared via a two-step process. PEO hydrogels were prepared by gamma-ray irradiation (radiation dose: 50 kGy, does rate: 7.66 kGy/h), and then grafting by either MAA or AAc monomers onto the PEO hydrogels with subsequent irradiation (radiation dose: 5-20 kGy, dose rate: 2.15 kGy/h). These grafted hydrogels showed a pH-sensitive swelling behavior. The grafted hydogels were used as a carrier for the drug delivery systems for the controlled release of insulin. Drug-loaded hydrogels were placed in simulated gastric fluid (SGF, pH 1.2) for 2 hr and then in simulated intestinal fluid (SIF, pH 6.8). The in vitro drug release behaviors of these hydrogels were examined by quantification analysis with a UV/vis spectrophotometer. The equilibrium swelling measurements of these hydrogels, which were carried out in simulated gastrointestinal fluids, showed a pH-sensitive nature. The in vitro release profiles of the drugs were obtained in both a simulated gastric fluid and simulated intestinal fluid. The release behavior of the pH-sensitive PEO-g-MAA and PEO-g-AAc hydrogels indicated that these gels could be applied successfully for oral drug delivery to the gastrointestinal tract. . (authors)

  9. A fixed cations and low Tg polymer: the poly(4-vinyl-pyridine) quaternized by poly(ethylene oxide) links. Conductivity study; Un electrolyte polymere a cations fixes et bas Tg: les poly(4-vinylpyridine) quaternisees par des chainons de poly(oxyde d`ethylene). Etude de la conductivite

    Energy Technology Data Exchange (ETDEWEB)

    Gramain, Ph. [Ecole Nationale Superieure de Chimie de Montpellier, 34 (France); Frere, Y. [Centre National de la Recherche Scientifique (CNRS), 67 - Strasbourg (France). Institut Charles Sadron

    1996-12-31

    The spontaneous ionic polymerization of 4-vinyl-pyridine in presence of mono-tosylated or bromated short chains of poly(ethylene oxide)-(PEO) is used to prepare amorphous comb-like poly-cations with low Tg. The polymer electrolyte properties of these new structures have been studied without any addition of salts. The ionic conductivity of these fixed cation poly-electrolytes depends on the length of the grafted PEO and varies from 10{sup -7} to 10{sup -4} S/cm between 25 and 80 deg. C. It is only weakly dependent on the nature of the cation but it is controlled by the movements of the pyridinium cation which are facilitated by the plastifying effect of the POE chains which do not directly participate to the ionic transport. (J.S.) 17 refs.

  10. A fixed cations and low Tg polymer: the poly(4-vinyl-pyridine) quaternized by poly(ethylene oxide) links. Conductivity study; Un electrolyte polymere a cations fixes et bas Tg: les poly(4-vinylpyridine) quaternisees par des chainons de poly(oxyde d`ethylene). Etude de la conductivite

    Energy Technology Data Exchange (ETDEWEB)

    Gramain, Ph [Ecole Nationale Superieure de Chimie de Montpellier, 34 (France); Frere, Y [Centre National de la Recherche Scientifique (CNRS), 67 - Strasbourg (France). Institut Charles Sadron

    1997-12-31

    The spontaneous ionic polymerization of 4-vinyl-pyridine in presence of mono-tosylated or bromated short chains of poly(ethylene oxide)-(PEO) is used to prepare amorphous comb-like poly-cations with low Tg. The polymer electrolyte properties of these new structures have been studied without any addition of salts. The ionic conductivity of these fixed cation poly-electrolytes depends on the length of the grafted PEO and varies from 10{sup -7} to 10{sup -4} S/cm between 25 and 80 deg. C. It is only weakly dependent on the nature of the cation but it is controlled by the movements of the pyridinium cation which are facilitated by the plastifying effect of the POE chains which do not directly participate to the ionic transport. (J.S.) 17 refs.

  11. (ethylene terephthalate) biomimetic composites

    Indian Academy of Sciences (India)

    In vitro bioactivity of the HAp/PEA-co-PET composites was studied by soaking in simulated .... 2.2d Characterization of cyclic oligomers: The C-OEA, ... GENESIS2000, EDAX) for microanalysis. ... Both spectra did not show the signal of end.

  12. Ethylene, seed germination, and epinasty.

    Science.gov (United States)

    Stewart, E R; Freebairn, H T

    1969-07-01

    Ethylene activity in lettuce seed (Lactuca satina) germination and tomato (Lycopersicon esculentum) petiole epinasty has been characterized by using heat to inhibit ethylene synthesis. This procedure enabled a separation of the production of ethylene from the effect of ethylene. Ethylene was required in tomato petioles to produce the epinastic response and auxin was found to be active in producing epinasty through a stimulation of ethylene synthesis with the resulting ethylene being responsible for the epinasty. In the same manner, it was shown that gibberellic acid stimulated ethylene synthesis in lettuce seeds. The ethylene produced then in turn stimulated the seeds to germinate. It was hypothesized that ethylene was the intermediate which caused epinasty or seed germination. Auxin and gibberellin primarily induced their response by stimulating ethylene production.

  13. Photocatalyst based on TiO2 nanotube arrays co-decorated with CdS quantum dots and reduced graphene oxide irradiated by γ rays for effective degradation of ethylene

    Science.gov (United States)

    Zhang, Quan; Ye, Shengying; Song, Xianliang; Luo, Shucan

    2018-06-01

    We report herein a means of transforming TiO2 nanotube arrays (TNAs) from an amorphous state to an anatase crystal state (denoted as ∗TNAs), and present a single-step synthetic route for preparing CdS quantum dots (CdS QDs) as well as reduced graphene oxide (rGO) through gamma-ray irradiation. The as-prepared ∗TNAs, CdS QDs, and rGO, which had all been subjected to gamma-ray irradiation, were then assembled together to produce the desired heterojunction (denoted as CdS QDs/rGO-∗TNAs). X-ray diffraction (XRD), field-emission scanning electron microscopy (FESEM), ultraviolet/visible diffuse-reflectance spectroscopy (UV/Vis DRS), Fourier-transform infrared spectroscopy (FTIR), micro-Raman spectrometry (RS), atomic force microscopy (AFM), and X-ray photoelectron spectroscopy (XPS) have been applied to characterize the appearance and performance of this photocatalyst. The photocatalytic activity of CdS QDs/rGO-∗TNAs towards ethylene degradation has been measured by placing it in a simulated cold-storage environment, the temperature and humidity of which were set at about 3 ± 1 °C and 75-90%, respectively. The results showed that the rate constant (K) of ethylene degradation could reach up to 1.07 × 10-3 min-1 with CdS QDs/rGO-∗TNAs, as compared to 2.30 × 10-4 min-1 with ∗TNAs and 6.25 × 10-4 min-1 with CdS QDs-∗TNAs, indicating that the constructed CdS QDs/rGO-∗TNAs constitutes a promising photocatalyst for ethylene removal in a cold storage environment.

  14. Chemical recycling of poly(ethylene terephthalate. Application to the synthesis of multiblock copolyesters

    Directory of Open Access Journals (Sweden)

    F. Malek

    2014-08-01

    Full Text Available The chemical recycling of the poly(ethylene terephthalate, (PET, has been successfully carried out by glycolysis in the presence of bis (2-hydroxyethyl terephthalate (BHET resulting in the formation of hydroxytelechelic oligomers. These oligomers were then treated with carboxytelechelic poly(ε-caprolactone oligomers of Mn = 2300 and Mn = 730 g•mol–1 molecular weight, in the absence or presence of the titanium tetrabutyloxide (Ti(OBu4 as a catalyst to get multiblock copolyesters. The chemical structure of the synthesized copolyesters was investigated by size exclusion chromatography (SEC and proton Nuclear Magnetic Resonance (1H NMR spectroscopy. Moreover the differential scanning calorimetry (DSC was used to explore their thermal properties. The ester-ester interchange reaction was observed between the two oligopolyesters, was studied and discussed in detail.

  15. Análisis microbiológico de plantas medicinales con óxido de etileno Microbiologic analysis of medicinal plants using ethylene oxide

    Directory of Open Access Journals (Sweden)

    Mausy Lorena Torres Rojas

    2007-08-01

    ón se encontraron microorganismos como: Citrobacter, Serrratia, Klebsiella, Staphylococcus, Clostridium y Pseudomonas. Algunos de ellos fueron encontrados en las muestras de Caléndula y Sen después de la esterilización con óxido de etileno.From prehistoric times, use of curative plants is one of the more ancient and widespread medical therapies, (Wust, 2003. Each culture has developed its folk medicine traditions, with remedies and rituals using native plants. Health World Organization (HWO, by means of some statements, has expressed its role as for need to assess use of medicinal plants within health scope, considering that 80% of world population depend on these ones as for health primary care (Alonso, 1998. In face of this need, and on concern about supply of high quality products, research performed allow us to assess some of raw materials, e.g.: Boldo (Pneumus boldus, Calédula (Calendula officinalis, Sen (Casia angustifolia Vahl, Fucus ( Fucus vesiculosas L, and Spirulina (Spirulina maxima, with a high demmand in market. Aim of this study was to assess microbiologic quality, and to establish if sterilization process using ethylene oxide had an significative effect on the raw material to be assessed. Authors made a count of aerobe mesophile microorganismes, fungi, yeasts, and absence/presence tests for pathogen microorganisms like Escherichia coli, Pseudomonas aeruginosa, Salmonella s.p., Clostridium perfringes, and Staphylococcus aureus. These test were performed using specific culture media: TNS, EMB, CETRIMIDE, XLD, B.P., OGY (fungi and yeasts, and Plate Count (aerobe mesophiles. Results from study samples allows us to obtain significant data, related to sterilization, as well as the mesophile, fungi, yeasts count. In above samples, befor sterilization, we found microorganisms like: Citrobacter, Serratia, Klebsiella, Staphyulococcus, Clostridium, and Pseudomonas. Some were found in Caléndula and Sen samples after sterilization using Ethilene oxide.

  16. Tau Oligomers as Pathogenic Seeds: Preparation and Propagation In Vitro and In Vivo.

    Science.gov (United States)

    Gerson, Julia E; Sengupta, Urmi; Kayed, Rakez

    2017-01-01

    Tau oligomers have been shown to be the main toxic tau species in a number of neurodegenerative disorders. In order to study tau oligomers both in vitro and in vivo, we have established methods for the reliable preparation, isolation, and detection of tau oligomers. Methods for the seeding of tau oligomers, isolation of tau oligomers from tissue, and detection of tau oligomers using tau oligomer-specific antibodies by biochemical and immunohistochemical methods are detailed below.

  17. Self-assembly of aniline oligomers

    Czech Academy of Sciences Publication Activity Database

    Zhao, Y.; Tomšík, Elena; Wang, J.; Morávková, Zuzana; Zhigunov, Alexander; Stejskal, Jaroslav; Trchová, Miroslava

    2013-01-01

    Roč. 8, č. 1 (2013), s. 129-137 ISSN 1861-4728 R&D Projects: GA ČR GA202/09/1626; GA ČR GAP205/12/0911 Institutional research plan: CEZ:AV0Z40500505 Institutional support: RVO:61389013 Keywords : morphology * oligoaniline * oligomers Subject RIV: CD - Macromolecular Chemistry Impact factor: 3.935, year: 2013

  18. Photopolymerizable silicone monomers, oligomers, and resins

    International Nuclear Information System (INIS)

    Jacobine, A.F.; Nakos, S.T.

    1992-01-01

    The purpose of this chapter is to acquaint the general photopolymer researcher with the historical development of the chemistry and technology of photopolymerizable silicone monomers, fluids, and resins. The current status of research in these areas is assessed. The focus of this chapter is not only on the polymer chemistry and application of this technology, but also on important aspects of the synthetic chemistry involved in the preparation of UV-curable silicone monomers, oligomers, and resins. 236 refs., 6 tabs

  19. Multicolored, Low-Voltage-Driven, Flexible Organic Electrochromic Devices Based on Oligomers.

    Science.gov (United States)

    Wan, Zhijun; Zeng, Jinming; Li, Hui; Liu, Ping; Deng, Wenji

    2018-04-20

    In this study, a series of organic conjugated oligomers containing 3,4-ethylenedioxythiophene (EDOT) and aromatic groups are synthesized, which are as follows: 2,5-di(methyl benzoate)-3,4-ethylenedioxy-thiophene (1EDOT-2B-COOCH 3 ), 5,5'-di(methyl benzoate)-2,2'-bi(3,4-ethylenedioxythiophene) (2EDOT-2B-COOCH 3 ), 5,5″-di(methyl benzoate)-2,2':5',2″-ter(3,4-ethylenedioxythiophene) (3EDOT-2B-COOCH 3 ), and 5,5″'-di(methyl benzoate)-2,2':5',2″: 5″,2″'-quater(3,4-ethylenedioxythiophene) (4EDOT-2B-COOCH 3 ). Using these oligomers as active materials, flexible organic electrochromic devices are fabricated. The device structure is indium tin oxide-PET plastic slide (ITO-PET)/active layer/conducting gel/ITO-PET, and the electrochromic properties of oligomers are investigated. These oligomers exhibit reversible color changes upon electrochemical doping and dedoping. The highest optical contrast is exhibited by 4EDOT-2B-COOCH 3 , which is 75.2% at 700 nm. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  20. High-capacity conductive nanocellulose paper sheets for electrochemically controlled extraction of DNA oligomers.

    Directory of Open Access Journals (Sweden)

    Aamir Razaq

    Full Text Available Highly porous polypyrrole (PPy-nanocellulose paper sheets have been evaluated as inexpensive and disposable electrochemically controlled three-dimensional solid phase extraction materials. The composites, which had a total anion exchange capacity of about 1.1 mol kg(-1, were used for extraction and subsequent release of negatively charged fluorophore tagged DNA oligomers via galvanostatic oxidation and reduction of a 30-50 nm conformal PPy layer on the cellulose substrate. The ion exchange capacity, which was, at least, two orders of magnitude higher than those previously reached in electrochemically controlled extraction, originated from the high surface area (i.e. 80 m(2 g(-1 of the porous composites and the thin PPy layer which ensured excellent access to the ion exchange material. This enabled the extractions to be carried out faster and with better control of the PPy charge than with previously employed approaches. Experiments in equimolar mixtures of (dT(6, (dT(20, and (dT(40 DNA oligomers showed that all oligomers could be extracted, and that the smallest oligomer was preferentially released with an efficiency of up to 40% during the reduction of the PPy layer. These results indicate that the present material is very promising for the development of inexpensive and efficient electrochemically controlled ion-exchange membranes for batch-wise extraction of biomolecules.

  1. High-performance liquid chromatography/electrospray mass spectrometry for the analysis of modified bases in DNA: 7-(2-hydroxyethyl)guanine, the major ethylene oxide-DNA adduct.

    Science.gov (United States)

    Leclercq, L; Laurent, C; De Pauw, E

    1997-05-15

    A method was developed for the analysis of 7-(2-hydroxyethyl)guanine (7HEG), the major DNA adduct formed after exposure to ethylene oxide (EO). The method is based on DNA neutral thermal hydrolysis, adduct micro-concentration, and final characterization and quantification by HPLC coupled to single-ion monitoring electrospray mass spectrometry (HPLC/SIR-ESMS). The method was found to be selective, sensitive, and easy to handle with no need for enzymatic digestion or previous sample derivatization. Detection limit was found to be close to 1 fmol of adduct injected (10(-10) M), thus allowing the detection of approximately three modified bases on 10(8) intact nucleotides in blood sample analysis. Quantification results are shown for 7HEG after calf thymus DNA and blood exposure to various doses of EO, in both cases obtaining clear dose-response relationships.

  2. Amyloid β oligomers in Alzheimer's disease pathogenesis, treatment, and diagnosis.

    Science.gov (United States)

    Viola, Kirsten L; Klein, William L

    2015-02-01

    Protein aggregation is common to dozens of diseases including prionoses, diabetes, Parkinson's and Alzheimer's. Over the past 15 years, there has been a paradigm shift in understanding the structural basis for these proteinopathies. Precedent for this shift has come from investigation of soluble Aβ oligomers (AβOs), toxins now widely regarded as instigating neuron damage leading to Alzheimer's dementia. Toxic AβOs accumulate in AD brain and constitute long-lived alternatives to the disease-defining Aβ fibrils deposited in amyloid plaques. Key experiments using fibril-free AβO solutions demonstrated that while Aβ is essential for memory loss, the fibrillar Aβ in amyloid deposits is not the agent. The AD-like cellular pathologies induced by AβOs suggest their impact provides a unifying mechanism for AD pathogenesis, explaining why early stage disease is specific for memory and accounting for major facets of AD neuropathology. Alternative ideas for triggering mechanisms are being actively investigated. Some research favors insertion of AβOs into membrane, while other evidence supports ligand-like accumulation at particular synapses. Over a dozen candidate toxin receptors have been proposed. AβO binding triggers a redistribution of critical synaptic proteins and induces hyperactivity in metabotropic and ionotropic glutamate receptors. This leads to Ca(2+) overload and instigates major facets of AD neuropathology, including tau hyperphosphorylation, insulin resistance, oxidative stress, and synapse loss. Because different species of AβOs have been identified, a remaining question is which oligomer is the major pathogenic culprit. The possibility has been raised that more than one species plays a role. Despite some key unknowns, the clinical relevance of AβOs has been established, and new studies are beginning to point to co-morbidities such as diabetes and hypercholesterolemia as etiological factors. Because pathogenic AβOs appear early in the disease, they

  3. Inhibition of Heme Peroxidase During Phenol Derivatives Oxidation. Possible Molecular Cloaking of the Active Center

    Directory of Open Access Journals (Sweden)

    Juozas Kulys

    2005-10-01

    Full Text Available Abstract: Ab initio quantum chemical calculations have been applied to the study of the molecular structure of phenol derivatives and oligomers produced during peroxidasecatalyzed oxidation. The interaction of substrates and oligomers with Arthromyces ramosus peroxidase was analyzed by docking methods. The most possible interaction site of oligomers is an active center of the peroxidase. The complexation energy increases with increasing oligomer length. However, the complexed oligomers do not form a precise (for the reaction hydrogen bonding network in the active center of the enzyme. It seems likely that strong but non productive docking of the oligomers determines peroxidase inhibition during the reaction.

  4. Backbone conformation affects duplex initiation and duplex propagation in hybridisation of synthetic H-bonding oligomers.

    Science.gov (United States)

    Iadevaia, Giulia; Núñez-Villanueva, Diego; Stross, Alexander E; Hunter, Christopher A

    2018-06-06

    Synthetic oligomers equipped with complementary H-bond donor and acceptor side chains form multiply H-bonded duplexes in organic solvents. Comparison of the duplex forming properties of four families of oligomers with different backbones shows that formation of an extended duplex with three or four inter-strand H-bonds is more challenging than formation of complexes that make only two H-bonds. The stabilities of 1 : 1 complexes formed between length complementary homo-oligomers equipped with either phosphine oxide or phenol recognition modules were measured in toluene. When the backbone is very flexible (pentane-1,5-diyl thioether), the stability increases uniformly by an order of magnitude for each additional base-pair added to the duplex: the effective molarities for formation of the first intramolecular H-bond (duplex initiation) and subsequent intramolecular H-bonds (duplex propagation) are similar. This flexible system is compared with three more rigid backbones that are isomeric combinations of an aromatic ring and methylene groups. One of the rigid systems behaves in exactly the same way as the flexible backbone, but the other two do not. For these systems, the effective molarity for formation of the first intramolecular H-bond is the same as that found for the other two backbones, but additional H-bonds are not formed between the longer oligomers. The effective molarities are too low for duplex propagation in these systems, because the oligomer backbones cannot adopt conformations compatible with formation of an extended duplex.

  5. Pigments and oligomers for inks - moving towards the best combination

    International Nuclear Information System (INIS)

    Hutchinson, I.; Smith, S.; Grierson, W.; Devine, E.

    1999-01-01

    The formulation of UV curable printing inks depends on several complex factors. If the individual components of the ink are not complementary, then performance problems can arise. One critical combination is that between the pigment and the oligomer. In a new approach to improve understanding of pigment/oligomer interactions, the resources of a pigment manufacturer and an oligomer manufacturer have been combined to investigate the problem. Initial screening of process yellow pigments and several oligomer types highlighted performance variations which were then examined in more detail

  6. Laccase-Catalyzed Synthesis of Low-Molecular-Weight Lignin-Like Oligomers and their Application as UV-Blocking Materials.

    Science.gov (United States)

    Lim, Jieyan; Sana, Barindra; Krishnan, Ranganathan; Seayad, Jayasree; Ghadessy, Farid J; Jana, Satyasankar; Ramalingam, Balamurugan

    2018-02-02

    The laccase-catalyzed oxidative polymerization of monomeric and dimeric lignin model compounds was carried out with oxygen as the oxidant in aqueous medium. The oligomers were characterized by using gel permeation chromatography (GPC) and matrix-assisted laser desorption ionization time-of-flight mass spectroscopy (MALDI-TOF MS) analysis. Oxidative polymerization led to the formation of oligomeric species with a number-average molecular weight (M n ) that ranged from 700 to 2300 Da with a low polydispersity index. Spectroscopic analysis provided insight into the possible modes of linkages present in the oligomers, and the oligomerization is likely to proceed through the formation of C-C linkages between phenolic aromatic rings. The oligomers were found to show good UV light absorption characteristics with high molar extinction coefficient (5000-38 000 m -1  cm -1 ) in the UV spectral region. The oligomers were blended independently with polyvinyl chloride (PVC) by using solution blending to evaluate the compatibility and UV protection ability of the oligomers. The UV/Vis transmittance spectra of the oligomer-embedded PVC films indicated that these lignin-like oligomers possessed a notable ability to block UV light. In particular, oligomers obtained from vanillyl alcohol and the dimeric lignin model were found to show good photostability in accelerated UV weathering experiments. The UV-blocking characteristics and photostability were finally compared with the commercial low-molecular-weight UV stabilizer 2,4-dihydroxybenzophenone. © 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  7. Mechanistic studies of ethylene biosynthesis in higher plants

    International Nuclear Information System (INIS)

    McGeehan, G.M.

    1986-01-01

    Ethylene is a plant hormone that elicits a wide variety of responses in plant tissue. Among these responses are the hastening of abscission, ripening and senescence. In 1979 it was discovered that 1-amino-1-cyclopropane carboxylic acid is the immediate biosynthetic precursor to ethylene. Given the obvious economic significance of ethylene production the authors concentrated their studies on the conversion of ACC to ethylene. They delved into mechanistic aspects of ACC oxidation and they studied potential inhibitors of ethylene forming enzyme (EFE). They synthesized various analogs of ACC and found that EFE shows good stereodiscrimination among alkyl substituted ACC analogs with the 1R, 2S stereoisomer being processed nine times faster than the 1S, 2R isomer in the MeACC series. They also synthesized 2-cyclopropyl ACC which is a good competitive inhibitor of EFE. This compound also causes time dependent loss of EFE activity leading us to believe it is an irreversible inhibitor of ethylene formation. The synthesis of these analogs has also allowed them to develop a spectroscopic technique to assign the relative stereochemistry of alkyl groups. 13 C NMR allows them to assign the alkyl stereochemistry based upon gamma-shielding effects on the carbonyl resonance. Lastly, they measured kinetic isotope effects on the oxidation of ACC in vivo and in vitro and found that ACC is oxidized by a rate-determining 1-electron removal from nitrogen in close accord with mechanisms for the oxidation of other alkyl amines

  8. In situ, Cr K-edge XAS study on the Phillips catalyst : activation and ethylene polymerization

    NARCIS (Netherlands)

    Groppo, E.; Prestipino, C.; Cesano, F.; Bonino, F.; Bordiga, S.; Lamberti, C.; Thuene, P.C.; Niemantsverdriet, J.W.; Zecchina, A.

    2005-01-01

    In this in situ EXAFS and XANES study on the Phillips ethylene-polymerization Cr/SiO2 catalyst, two polymerization routes are investigated and compared. The first mimics that adopted in industrial plants, where ethylene is dosed directly on the oxidized catalyst, while in the second the oxidized

  9. Recovery and purification of ethylene

    Science.gov (United States)

    Reyneke, Rian [Katy, TX; Foral, Michael J [Aurora, IL; Lee, Guang-Chung [Houston, TX; Eng, Wayne W. Y. [League City, TX; Sinclair, Iain [Warrington, GB; Lodgson, Jeffery S [Naperville, IL

    2008-10-21

    A process for the recovery and purification of ethylene and optionally propylene from a stream containing lighter and heavier components that employs an ethylene distributor column and a partially thermally coupled distributed distillation system.

  10. Polymeric film of 6-arm-poly(ethylene glycol) amine graphene oxide with poly (ε-caprolactone): Adherence and growth of adipose derived mesenchymal stromal cells culture on rat bladder

    Science.gov (United States)

    Durán, Marcela; Durán, Nelson; Luzo, Angela C. M.; Duarte, Adriana S. S.; Volpe, Bruno B.; Ceragioli, Helder J.; Andrade, Patricia F.; De Souza, Joel G.; Fávaro, Wagner J.

    2017-06-01

    Nanotechnology has been more present in different fields related to health. The need to find a durable material, of easy use, and which does not interfere significantly in the growth and differentiation of stem cells for the construction of a scaffold for use in urologic surgery, with the purpose of reducing infections, regeneration times and even graft rejection during reconstitution in patients with urethral stricture was conducted a broad survey of information about this and came to the consensus of this project: using graphene oxide, a widely studied nanomaterials which has been presenting numerous beneficial results when in contact with the adipose-derived stem cells. Advanced techniques for the growth, differentiation and proliferation of adipose-derived stem cells were used, as well as the characterization of graphene oxide sheets. For this study, it was prepared the graphene oxide/6 ARM-Poly (ethylene glycol) amine films with poly (ε-caprolactone). The graphene suspension in organic solvent was prepared by using an ultrasonicator bath and subsequently, the film was formed by solvent evaporation. Total characterization of graphene oxide/6 ARM-PEG-amine/ poly (ε-caprolactone) film was carried out. It was tested growth and adhesion of adipose-derived stem cells on the film, as well as, were verified the histopathological effects of this scaffold when implanted in the urinary bladder to repair the lesion. Our results demonstrated that this scaffold with adipose-derived stem cells enhanced the repair in rat urinary bladder defect model, resulting in a regular bladder. Improved organized muscle bundles and urothelial layer were observed in animals treated with this scaffold with adipose-derived stem cells compared with those treated only suture thread or scaffold. Thus, our biomaterial could be suitable for tissue engineered urinary tract reconstruction.

  11. Polymeric film of 6-arm-poly(ethylene glycol) amine graphene oxide with poly (ε-caprolactone): Adherence and growth of adipose derived mesenchymal stromal cells culture on rat bladder

    International Nuclear Information System (INIS)

    Durán, Marcela; Durán, Nelson; Fávaro, Wagner J.; Luzo, Angela C.M.; Duarte, Adriana S. S.; Volpe, Bruno B.; Ceragioli, Helder J.; Andrade, Patricia F.; De Souza, Joel G.

    2017-01-01

    Nanotechnology has been more present in different fields related to health. The need to find a durable material, of easy use, and which does not interfere significantly in the growth and differentiation of stem cells for the construction of a scaffold for use in urologic surgery, with the purpose of reducing infections, regeneration times and even graft rejection during reconstitution in patients with urethral stricture was conducted a broad survey of information about this and came to the consensus of this project: using graphene oxide, a widely studied nanomaterials which has been presenting numerous beneficial results when in contact with the adipose-derived stem cells. Advanced techniques for the growth, differentiation and proliferation of adipose-derived stem cells were used, as well as the characterization of graphene oxide sheets. For this study, it was prepared the graphene oxide/6 ARM-Poly (ethylene glycol) amine films with poly (ε-caprolactone). The graphene suspension in organic solvent was prepared by using an ultrasonicator bath and subsequently, the film was formed by solvent evaporation. Total characterization of graphene oxide/6 ARM-PEG-amine/ poly (ε-caprolactone) film was carried out. It was tested growth and adhesion of adipose-derived stem cells on the film, as well as, were verified the histopathological effects of this scaffold when implanted in the urinary bladder to repair the lesion. Our results demonstrated that this scaffold with adipose-derived stem cells enhanced the repair in rat urinary bladder defect model, resulting in a regular bladder. Improved organized muscle bundles and urothelial layer were observed in animals treated with this scaffold with adipose-derived stem cells compared with those treated only suture thread or scaffold. Thus, our biomaterial could be suitable for tissue engineered urinary tract reconstruction. (paper)

  12. Oligomers and Polymers Based on Pentacene Building Blocks

    Science.gov (United States)

    Lehnherr, Dan; Tykwinski, Rik R.

    2010-01-01

    Functionalized pentacene derivatives continue to provide unique materials for organic semiconductor applications. Although oligomers and polymers based on pentacene building blocks remain quite rare, recent synthetic achievements have provided a number of examples with varied structural motifs. This review highlights recent work in this area and, when possible, contrasts the properties of defined-length pentacene oligomers to those of mono- and polymeric systems.

  13. Improved surface hydrophilicity and antifouling property of polysulfone ultrafiltration membrane with poly(ethylene glycol) methyl ether methacrylate grafted graphene oxide nanofillers

    Science.gov (United States)

    Wang, Haidong; Lu, Xiaofei; Lu, Xinglin; Wang, Zhenghui; Ma, Jun; Wang, Panpan

    2017-12-01

    In this study, the GO-g-P(PEGMA) nanoplates were first synthesized by grafting hydrophilic poly (poly (ethylene glycol) methyl ether methacrylate) via surface-initiated atom transfer radical polymerization (SI-ATRP) method. A novel polysulfone (PSF) nanocomposite membrane using GO-g-P(PEGMA) nanoplates as nanofillers was fabricated. FTIR, TGA, 1H NMR, GPC and TEM were applied to verify the successful synthesis of the prepared nanoplates, while SEM, AFM, XPS, contact angle goniometry and filtration experiments were used to characterize the fabricated nanocomposite membranes. It was found that the new prepared nanofillers were well dispersed in organic PSF matrix, and the PSF/GO-g-P(PEGMA) nanocomposite membrane showed significant improvements in water flux and flux recovery rate. Based on the results of resistance-in-series model, the nanocomposite membrane exhibited superior resistance to the irreversible fouling. The excellent filtration and antifouling performance are attributed to the segregation of GO-g-P(PEMGA) nanofillers toward the membrane surface and the pore walls. Notably, the blended nanofillers appeared a stable retention in/on nanocomposite membrane after 30 days of washing time. The demonstrated method of synthesis GO-g-P(PEGMA) in this study can also be extended to preparation of other nanocomposite membrane in future.

  14. Preparation of Stable Amyloid-β Oligomers Without Perturbative Methods.

    Science.gov (United States)

    Kotler, Samuel A; Ramamoorthy, Ayyalusamy

    2018-01-01

    Soluble amyloid-β (Aβ) oligomers have become a focal point in the study of Alzheimer's disease due to their ability to elicit cytotoxicity. A number of recent studies have concentrated on the structural characterization of soluble Aβ oligomers to gain insight into their mechanism of toxicity. Consequently, providing reproducible protocols for the preparation of such oligomers is of utmost importance. The method presented in this chapter details a protocol for preparing an Aβ oligomer, with a primarily disordered secondary structure, without the need for chemical modification or amino acid substitution. Due to the stability of these disordered Aβ oligomers and the reproducibility with which they form, they are amenable for biophysical and high-resolution structural characterization.

  15. Water is a poor solvent for densely grafted poly(ethylene oxide) chains: a conclusion drawn from a self-consistent field theory-based analysis of neutron reflectivity and surface pressure-area isotherm data.

    Science.gov (United States)

    Lee, Hoyoung; Kim, Dae Hwan; Witte, Kevin N; Ohn, Kimberly; Choi, Je; Akgun, Bulent; Satija, Sushil; Won, You-Yeon

    2012-06-21

    By use of a combined experimental and theoretical approach, a model poly(ethylene oxide) (PEO) brush system, prepared by spreading a poly(ethylene oxide)-poly(n-butyl acrylate) (PEO-PnBA) amphiphilic diblock copolymer onto an air-water interface, was investigated. The polymer segment density profiles of the PEO brush in the direction normal to the air-water interface under various grafting density conditions were determined by using the neutron reflectivity (NR) measurement technique. To achieve a theoretically sound analysis of the reflectivity data, we used a data analysis method that utilizes the self-consistent field (SCF) theoretical modeling as a tool for predicting expected reflectivity results for comparison with the experimental data. Using this data analysis technique, we discovered that the effective Flory-Huggins interaction parameter of the PEO brush chains is significantly greater than that corresponding to the θ condition in Flory-Huggins solutions (i.e., χ(PEO-water)(brush chains)/χ(PEO-water)(θ condition) ≈ 1.2), suggesting that contrary to what is more commonly observed for PEO in normal situations (χ(PEO-water)(free chains)/χ(PEO-water)(θ condition) ≈ 0.92), the PEO chains are actually not "hydrophilic" when they exist as polymer brush chains, because of the many body interactions that are forced to be effective in the brush situation. This result is further supported by the fact that the surface pressures of the PEO brush calculated on the basis of the measured χ(PEO-water) value are in close agreement with the experimental surface pressure-area isotherm data. The SCF theoretical analysis of the surface pressure behavior of the PEO brush also suggests that even though the grafted PEO chains experience a poor solvent environment, the PEO brush layer exhibits positive surface pressures, because the hydrophobicity of the PEO brush chains (which favors compression) is insufficient to overcome the opposing effect of the chain

  16. Study of crystalline morphology and phase structure in poly(styrene-b-ethylene oxide-b-styrene) triblock copolymers bu solid state RMN spin diffusion

    International Nuclear Information System (INIS)

    Mantovani, Gerson L.; Phan, Trang; Bertin, Denis; Azevedo, Eduardo R. de; Bonagamba, Tito J.

    2009-01-01

    The phase structure and crystalline morphology of a series of polystyrene-b-polyethylene oxide-b-polystyrene (PS-b- PEO-b-PS) triblock copolymers, with different compositions and molecular weights, has been studied by solid-state NMR. WAXS and DSC measurements were used to detect the presence of crystalline domains of polyethylene oxide (PEO) blocks at room temperature as a function of the copolymer composition. 1 H NMR spin diffusion analyses provided an estimation of the size of the dispersed phases of the nano structured copolymers. (author)

  17. The level of ethylene biomarker in the renal failure of elderly patients analyzed by photoacoustic spectroscopy

    Science.gov (United States)

    Popa, C.; Patachia, M.; Banita, S.; Matei, C.; Bratu, A. M.; Dumitras, D. C.

    2013-12-01

    In recent years there has been a large increase in the areas related to developments in the prevention of diseases, especially in explaining the role of oxidative stress. Lipid peroxidation and oxidative stress contributes to morbidity in hemodialysis (HD) patients. It is therefore relevant to analyze the impact of oxidative stress and its related species (ethylene) immediately after dialysis treatment in order to prevent trauma in the renal failure of elderly patients. In this paper we describe recent progress in laser photoacoustic spectroscopy detection of ethylene in renal failure patients. We have found that HD treatment increases ethylene concentration in the exhaled breath of elderly patients and may intensify oxidative stress.

  18. Macrocyclic 2,7-Anthrylene Oligomers.

    Science.gov (United States)

    Yamamoto, Yuta; Wakamatsu, Kan; Iwanaga, Tetsuo; Sato, Hiroyasu; Toyota, Shinji

    2016-05-06

    A macrocyclic compound consisting of six 2,7-anthrylene units was successfully synthesized by Ni-mediated coupling of the corresponding dibromo precursor as a novel π-conjugated compound. This compound was sufficiently stable and soluble in organic solvents due to the presence of mesityl groups. X-ray analysis showed that the molecule had a nonplanar and hexagonal wheel-shaped framework of approximately S6 symmetry. The dynamic process between two S6 structures was observed by using the dynamic NMR technique, the barrier being 58 kJ mol(-1) . The spectroscopic properties of the hexamer were compared with those of analogous linear oligomers. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  19. Design, synthesis, and characterization of biomimetic oligomers

    DEFF Research Database (Denmark)

    Laursen, Jonas Striegler

    a helical arrangement found by DFT calculations. The designed oligomer indeed proved the existence of a ß-peptoid helical conformation by X-ray. Further studies of these compounds indicated a structured display in solution. These helices thus definitively show that the ß-peptoids should be considered......Peptides and proteins made from the 20 canonical amino acids are responsible for many processes necessary for organisms to function. Beside their composition, proteins obtain their activity and unique selectivity through an ability to display functionalities accurately in the three......, for their ability to mimic the structural elements seen in proteins. Two prominent peptidomimetics are ß-peptides and a-peptoids (N-alkylglycines), which have been shown to fold into helical and sheet-like arrangements. To expand the chemical space available for mimicking protein structure their features have been...

  20. PT-symmetry management in oligomer systems

    International Nuclear Information System (INIS)

    Horne, R L; Cuevas, J; Kevrekidis, P G; Whitaker, N; Abdullaev, F Kh; Frantzeskakis, D J

    2013-01-01

    We study the effects of management of the PT-symmetric part of the potential within the setting of Schrödinger dimer and trimer oligomer systems. This is done by rapidly modulating in time the gain/loss profile. This gives rise to a number of interesting properties of the system, which are explored at the level of an averaged equation approach. Remarkably, this rapid modulation provides for a controllable expansion of the region of exact PT-symmetry, depending on the strength and frequency of the imposed modulation. The resulting averaged models are analysed theoretically and their exact stationary solutions are translated into time-periodic solutions through the averaging reduction. These are, in turn, compared with the exact periodic solutions of the full non-autonomous PT-symmetry managed problem and very good agreement is found between the two. (paper)

  1. Effect of Conjugation Length on Photoinduced Charge-Transfer in π-Conjugated Oligomer-Acceptor Dyads

    KAUST Repository

    Jiang, Junlin

    2017-05-25

    A series of -conjugated oligomer-acceptor dyads were synthesized that feature oligo(phenylene ethynylene) (OPE) conjugated backbones end-capped with a naphthalene diimide (NDI) acceptor. The OPE segments vary in length from 4 to 8 phenylene ethynene units (PEn-NDI, where n = 4, 6 and 8). Fluorescence and transient absorption spectroscopy reveals that intramolecular OPE NDI charge transfer dominates the deactivation of excited states of the PEn-NDI oligomers. Both charge separation (CS) and charge recombination (CR) are strongly exothermic (G0CS ~ -1.1 and G0CR ~ -2.0 eV), and the driving forces do not vary much across the series because the oxidation and reduction potentials and singlet energies of the OPEs do not vary much with their length. Bimolecular photoinduced charge transfer between model OPEs that do not contain the NDI acceptors with methyl viologen was studied, and the results reveal that the absorption of the cation radical state (OPE+•) remains approximately constant ( ~ 575 nm) regardless of oligomer length. This finding suggests that the cation radical (polaron) of the OPE is relatively localized, effectively occupying a confined segment of n 4 repeat units in the longer oligomers. Photoinduced intramolecular electron transfer dynamics in the PEn-NDI series was investigated by UV-visible femtosecond transient absorption spectroscopy with visible and mid-infrared probes. Charge separation occurs on the 1 – 10 ps timescale, with the rates decreasing slightly with increased oligomer length (βCS ~ 0.15 Å-1). The rate for charge-recombination decreases in the sequence PE4-NDI > PE6-NDI ~ PE8-NDI. The discontinuous distance dependence in the rate for charge recombination may be related to the spatial localization of the positive polaron state in the longer oligomers.

  2. Effect of Conjugation Length on Photoinduced Charge-Transfer in π-Conjugated Oligomer-Acceptor Dyads

    KAUST Repository

    Jiang, Junlin; Alsam, Amani Abdu; Wang, Shanshan; Aly, Shawkat Mohammede; Pan, Zhenxing; Mohammed, Omar F.; Schanze, Kirk S.

    2017-01-01

    A series of -conjugated oligomer-acceptor dyads were synthesized that feature oligo(phenylene ethynylene) (OPE) conjugated backbones end-capped with a naphthalene diimide (NDI) acceptor. The OPE segments vary in length from 4 to 8 phenylene ethynene units (PEn-NDI, where n = 4, 6 and 8). Fluorescence and transient absorption spectroscopy reveals that intramolecular OPE NDI charge transfer dominates the deactivation of excited states of the PEn-NDI oligomers. Both charge separation (CS) and charge recombination (CR) are strongly exothermic (G0CS ~ -1.1 and G0CR ~ -2.0 eV), and the driving forces do not vary much across the series because the oxidation and reduction potentials and singlet energies of the OPEs do not vary much with their length. Bimolecular photoinduced charge transfer between model OPEs that do not contain the NDI acceptors with methyl viologen was studied, and the results reveal that the absorption of the cation radical state (OPE+•) remains approximately constant ( ~ 575 nm) regardless of oligomer length. This finding suggests that the cation radical (polaron) of the OPE is relatively localized, effectively occupying a confined segment of n 4 repeat units in the longer oligomers. Photoinduced intramolecular electron transfer dynamics in the PEn-NDI series was investigated by UV-visible femtosecond transient absorption spectroscopy with visible and mid-infrared probes. Charge separation occurs on the 1 – 10 ps timescale, with the rates decreasing slightly with increased oligomer length (βCS ~ 0.15 Å-1). The rate for charge-recombination decreases in the sequence PE4-NDI > PE6-NDI ~ PE8-NDI. The discontinuous distance dependence in the rate for charge recombination may be related to the spatial localization of the positive polaron state in the longer oligomers.

  3. BROMOETHANE, CHLOROETHANE AND ETHYLENE OXIDE INDUCED UTERINE NEOPLASMS IN B6C3F1 MICE FROM 2-YEAR NTP INHALATION BIOASSAYS: PATHOLOGY AND INCIDENCE DATA REVISITED

    Science.gov (United States)

    SUMMARY: Chloroethane, bromoethane and etjulene oxide represent a unique set of three chemicals that induce endometrial neoplasms in the uterus of B6C3F1 mice following an inhalation route of exposure. The results of the NTP's chronic bioassays with these three compounds resu...

  4. Comparative electrocatalytic oxidation of ethanol, ethylene glycol and glycerol in alkaline medium at Pd-decorated FeCo@Fe/C core-shell nanocatalysts

    CSIR Research Space (South Africa)

    Fashedemi, OO

    2014-05-01

    Full Text Available ) were explored, and compared with those of the Pd/C alone. FeCo@Fe@Pd/C exhibited a remarkable performance in all three alcohols but its best electrocatalytic activity was found in the oxidation of EG where the electrocatalytic rate constant (K...

  5. Structural and functional properties of prefibrillar α-synuclein oligomers.

    Science.gov (United States)

    Pieri, Laura; Madiona, Karine; Melki, Ronald

    2016-04-14

    The deposition of fibrillar alpha-synuclein (α-syn) within inclusions (Lewy bodies and Lewy neurites) in neurons and glial cells is a hallmark of synucleinopathies. α-syn populates a variety of assemblies ranging from prefibrillar oligomeric species to fibrils whose specific contribution to neurodegeneration is still unclear. Here, we compare the specific structural and biological properties of distinct soluble prefibrillar α-syn oligomers formed either spontaneously or in the presence of dopamine and glutaraldehyde. We show that both on-fibrillar assembly pathway and distinct dopamine-mediated and glutaraldehyde-cross-linked α-syn oligomers are only slightly effective in perturbing cell membrane integrity and inducing cytotoxicity, while mature fibrils exhibit the highest toxicity. In contrast to low-molecular weight and unstable oligomers, large stable α-syn oligomers seed the aggregation of soluble α-syn within reporter cells although to a lesser extent than mature α-syn fibrils. These oligomers appear elongated in shape. Our findings suggest that α-syn oligomers represent a continuum of species ranging from unstable low molecular weight particles to mature fibrils via stable elongated oligomers composed of more than 15 α-syn monomers that possess seeding capacity.

  6. Chemical and Biological Significance of Oenothein B and Related Ellagitannin Oligomers with Macrocyclic Structure

    Directory of Open Access Journals (Sweden)

    Takashi Yoshida

    2018-03-01

    Full Text Available In 1990, Okuda et al. reported the first isolation and characterization of oenothein B, a unique ellagitannin dimer with a macrocyclic structure, from the Oenothera erythrosepala leaves. Since then, a variety of macrocyclic analogs, including trimeric–heptameric oligomers have been isolated from various medicinal plants belonging to Onagraceae, Lythraceae, and Myrtaceae. Among notable in vitro and in vivo biological activities reported for oenothein B are antioxidant, anti-inflammatory, enzyme inhibitory, antitumor, antimicrobial, and immunomodulatory activities. Oenothein B and related oligomers, and/or plant extracts containing them have thus attracted increasing interest as promising targets for the development of chemopreventive agents of life-related diseases associated with oxygen stress in human health. In order to better understand the significance of this type of ellagitannin in medicinal plants, this review summarizes (1 the structural characteristics of oenothein B and related dimers; (2 the oxidative metabolites of oenothein B up to heptameric oligomers; (3 the distribution of oenotheins and other macrocyclic analogs in the plant kingdom; and (4 the pharmacological activities hitherto documented for oenothein B, including those recently found by our laboratory.

  7. Ethylene glycol poisoning

    African Journals Online (AJOL)

    Ethylene glycol poisoning. A 22-year-old male presented to the emergency centre after drinking 300 ml of antifreeze. Clinical examination was unremarkable except for a respiratory rate of 28 bpm, GCS of 9 and slight nystagmus. Arterial blood gas revealed: pH 7.167, pCO2. 3.01 kPa, pO2 13.0 kPa (on room air), HCO3-.

  8. Ethylene and protein synthesis

    Energy Technology Data Exchange (ETDEWEB)

    Osborne, D J

    1973-01-01

    Ethylene reduces the rate of expansion growth of cells and it is suggestive that the rate of expansion is controlled at least in part by the synthesis of hydroxyproline rich glycopeptides that are secreted with other polysaccharide material through the plasmalemma into the cell wall, thereby enhancing the thickness of the cell wall and also rendering it poorly extensible. In combination, auxin would appear to counteract the effect of ethylene in this respect, for although auxin enhances the synthesis of protein and the content in the cell walls, as well as causing some increase in wall thickness, it reduces the amount of hydroxyproline reaching the wall. Such effects may be instrumental in enhancing wall plasticity, the rate of expansion and the final cell size. These results indicate that ethylene and auxin together afford a dual regulatory system exerted through a control of a specific part of the protein synthetic pathway, the products of which regulate the rate of expansion, and the potential for expansion, of the plant cell wall. 38 references, 3 figures, 8 tables.

  9. Electron beam curing polyurethane acrylate oligomer in air

    International Nuclear Information System (INIS)

    Zhu, Zhenkang; Chen, Xing; Zhou, Jichun; Ma, Zue-Teh

    1988-01-01

    It has been found according to our synthesis that a novel kind of polyurethane acrylate oligomer can be cured by electron beam in the presence of oxygen, even at normal atomospheric levels, without any additives. Irradiation of the oligomer with substantially complete cure to a solid non-tacky state is quite remarkable. It has the same gel content (90 %) in air as in nitrogen at dose of 33 kGy. Double bond conversion of the oligomer is about 50 % by I.R. (author)

  10. Simultaneous detection of five different 2-hydroxyethyl-DNA adducts formed by ethylene oxide exposure, using a high-performance liquid chromatography/electrospray ionisation tandem mass spectrometry assay.

    Science.gov (United States)

    Tompkins, Elaine M; Jones, Donald J L; Lamb, John H; Marsden, Debbie A; Farmer, Peter B; Brown, Karen

    2008-01-01

    A method has been developed for the simultaneous detection and quantitation of five different 2-hydroxyethyl-DNA (HE-DNA) adducts that could be formed as a result of exposure to ethylene oxide (EO). In addition to the major N7-HE-guanine (N7-HEG) adducts this assay can also measure the less prevalent but potentially more biologically significant N1-HE-2'-deoxyadenosine (N1-HEdA), O(6)-HE-2'-deoxyguanosine (O(6)-HEdG), N(6)-HE-2'-deoxyadenosine (N(6)-HEdA) and N3-HE-2'-deoxyuridine adducts (N3-HEdU). The method involves the isolation of HE adducts from the unmodified nucleosides by either neutral thermal hydrolysis or enzymatic digestion, followed by high-performance liquid chromatographic (HPLC) purification, before detection and quantification by liquid chromatography tandem mass spectrometry (LC/MS/MS) using selective reaction monitoring (SRM). The limits of detection were in the range 0.5-25 fmol for each individual adduct, making this one of the most sensitive assays available for the detection of N7-HEG. To illustrate the possible applications of the assay, it has been employed in the measurement of endogenous/background and EO-induced HE adducts in a variety of DNA samples.

  11. SAXS and stability studies of iron-induced oligomers of bacterial frataxin CyaY.

    Directory of Open Access Journals (Sweden)

    Mostafa Fekry

    Full Text Available Frataxin is a highly conserved protein found in both prokaryotes and eukaryotes. It is involved in several central functions in cells, which include iron delivery to biochemical processes, such as heme synthesis, assembly of iron-sulfur clusters (ISC, storage of surplus iron in conditions of iron overload, and repair of ISC in aconitase. Frataxin from different organisms has been shown to undergo iron-dependent oligomerization. At least two different classes of oligomers, with different modes of oligomer packing and stabilization, have been identified. Here, we continue our efforts to explore the factors that control the oligomerization of frataxin from different organisms, and focus on E. coli frataxin CyaY. Using small-angle X-ray scattering (SAXS, we show that higher iron-to-protein ratios lead to larger oligomeric species, and that oligomerization proceeds in a linear fashion as a results of iron oxidation. Native mass spectrometry and online size-exclusion chromatography combined with SAXS show that a dimer is the most common form of CyaY in the presence of iron at atmospheric conditions. Modeling of the dimer using the SAXS data confirms the earlier proposed head-to-tail packing arrangement of monomers. This packing mode brings several conserved acidic residues into close proximity to each other, creating an environment for metal ion binding and possibly even mineralization. Together with negative-stain electron microscopy, the experiments also show that trimers, tetramers, pentamers, and presumably higher-order oligomers may exist in solution. Nano-differential scanning fluorimetry shows that the oligomers have limited stability and may easily dissociate at elevated temperatures. The factors affecting the possible oligomerization mode are discussed.

  12. Conjugated Polymers and Oligomers: Structural and Soft Matter Aspects

    DEFF Research Database (Denmark)

    This book identifies modern topics and current trends of structural and soft matter aspects of conjugated polymers and oligomers. Each chapter recognizes an active research line where structural perspective dominates research and therefore the book covers fundamental aspects of persistent...

  13. Binding Sites for Amyloid-β Oligomers and Synaptic Toxicity

    Science.gov (United States)

    Smith, Levi M.; Strittmatter, Stephen M.

    2017-01-01

    In Alzheimer’s disease (AD), insoluble and fibrillary amyloid-β (Aβ) peptide accumulates in plaques. However, soluble Aβ oligomers are most potent in creating synaptic dysfunction and loss. Therefore, receptors for Aβ oligomers are hypothesized to be the first step in a neuronal cascade leading to dementia. A number of cell-surface proteins have been described as Aβ binding proteins, and one or more are likely to mediate Aβ oligomer toxicity in AD. Cellular prion protein (PrPC) is a high-affinity Aβ oligomer binding site, and a range of data delineates a signaling pathway leading from Aβ complexation with PrPC to neuronal impairment. Further study of Aβ binding proteins will define the molecular basis of this crucial step in AD pathogenesis. PMID:27940601

  14. Organic heterostructures based on arylenevinylene oligomers deposited by MAPLE

    Czech Academy of Sciences Publication Activity Database

    Socol, M.; Preda, N.; Vacareanu, L.; Grigoras, M.; Socol, G.; Mihailescu, I. N.; Stanculescu, F.; Jelínek, Miroslav; Stanculescu, A.; Stoicanescu, M.

    2014-01-01

    Roč. 302, May (2014), s. 216-222 ISSN 0169-4332 Institutional support: RVO:68378271 Keywords : organic heterostructures * MAPLE * oligomer * optoelectronica Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 2.711, year: 2014

  15. Interactions of oxygen and ethylene with submonolayer Ag films supported on Ni(111).

    Science.gov (United States)

    Rettew, Robert E; Meyer, Axel; Senanayake, Sanjaya D; Chen, Tsung-Liang; Petersburg, Cole; Ingo Flege, J; Falta, Jens; Alamgir, Faisal M

    2011-06-21

    We investigate the oxidation of, and the reaction of ethylene with, Ni(111) with and without sub-monolayer Ag adlayers as a function of temperature. The addition of Ag to Ni(111) is shown to enhance the activity towards the ethylene epoxidation reaction, and increase the temperature at which ethylene oxide is stable on the surface. We present a systematic study of the formation of chemisorbed oxygen on the Ag-Ni(111) surfaces and correlate the presence and absence of O(1-) and O(2-) surface species with the reactivity towards ethylene. By characterizing the samples with low-energy electron microscopy (LEEM) in combination with X-ray photoelectron spectroscopy (XPS), we have identified specific growth of silver on step-edge sites and successfully increased the temperature at which the produced ethylene oxide remains stable, a trait which is desirable for catalysis.

  16. Effect of sodium phosphate salts on the thermodynamic properties of aqueous solutions of poly(ethylene oxide) 6000 at different temperatures

    International Nuclear Information System (INIS)

    Sadeghi, Rahmat; Hosseini, Rahim; Jamehbozorg, Bahman

    2008-01-01

    Precise density, sound velocity, water activity, and phase diagram measurements have been carried out on polyethylene oxide (PEO) in aqueous solutions of sodium di-hydrogen phosphate, di-sodium hydrogen phosphate, and tri-sodium phosphate over a range of temperatures at atmospheric pressure. The experimental density and sound velocity data are used to calculate the apparent specific volume and isentropic compressibility as a function of temperature and concentration. It was found that both of the apparent specific volume and isentropic compressibility of PEO in aqueous solutions increase by increasing temperature and charge on the anion of electrolytes. The results show that the slope of constant water activity lines increased with increasing the temperature and charge on the anion of electrolytes and the vapour pressure depression for an aqueous (PEO + sodium phosphate) system is more than the sum of those for the corresponding binary solutions. Furthermore, the effect of temperature and type of anion of salt on the salting-out effect of polyethylene oxide by sodium phosphate salts has been studied

  17. Effect of sodium phosphate salts on the thermodynamic properties of aqueous solutions of poly(ethylene oxide) 6000 at different temperatures

    Energy Technology Data Exchange (ETDEWEB)

    Sadeghi, Rahmat [Department of Chemistry, University of Kurdistan, Sanandaj (Iran, Islamic Republic of)], E-mail: rahsadeghi@yahoo.com; Hosseini, Rahim; Jamehbozorg, Bahman [Department of Chemistry, University of Kurdistan, Sanandaj (Iran, Islamic Republic of)

    2008-09-15

    Precise density, sound velocity, water activity, and phase diagram measurements have been carried out on polyethylene oxide (PEO) in aqueous solutions of sodium di-hydrogen phosphate, di-sodium hydrogen phosphate, and tri-sodium phosphate over a range of temperatures at atmospheric pressure. The experimental density and sound velocity data are used to calculate the apparent specific volume and isentropic compressibility as a function of temperature and concentration. It was found that both of the apparent specific volume and isentropic compressibility of PEO in aqueous solutions increase by increasing temperature and charge on the anion of electrolytes. The results show that the slope of constant water activity lines increased with increasing the temperature and charge on the anion of electrolytes and the vapour pressure depression for an aqueous (PEO + sodium phosphate) system is more than the sum of those for the corresponding binary solutions. Furthermore, the effect of temperature and type of anion of salt on the salting-out effect of polyethylene oxide by sodium phosphate salts has been studied.

  18. Oligomers and Polymers Based on Pentacene Building Blocks

    Directory of Open Access Journals (Sweden)

    Dan Lehnherr

    2010-04-01

    Full Text Available Functionalized pentacene derivatives continue to provide unique materials for organic semiconductor applications. Although oligomers and polymers based on pentacene building blocks remain quite rare, recent synthetic achievements have provided a number of examples with varied structural motifs. This review highlights recent work in this area and, when possible, contrasts the properties of defined-length pentacene oligomers to those of mono- and polymeric systems.

  19. Biophysical characterization data on Aβ soluble oligomers produced through a method enabling prolonged oligomer stability and biological buffer conditions

    Directory of Open Access Journals (Sweden)

    Amanda C. Crisostomo

    2015-09-01

    Aβ1-40 soluble oligomers are produced that are suitable for biophysical studies requiring sufficient transient stability to exist in their “native” conformation in biological phosphate-saline buffers for extended periods of time. The production involves an initial preparation of highly monomeric Aβ in a phosphate saline buffer that transitions to fibrils and oligomers through time incubation alone, without added detergents or non-aqueous chemicals. This criteria ensures that the only difference between initial monomeric Aβ reactant and subsequent Aβ oligomer products is their degree of peptide assembly. A number of chemical and biophysical methods were used to characterize the monomeric reactants and soluble oligomer and amyloid fibril products, including chemical cross-linking, Western blots, fraction solubility, thioflvain T binding, size exclusion chromatography, transmission electron micrscopy, circular dichroism spectroscopy, and fluorescence resonance energy transfer.

  20. MinimalSpild – Ethylene

    DEFF Research Database (Denmark)

    2017-01-01

    Ethylene is a gas and an important plant hormone, which can have an adverse effect on quality af potted plants......Ethylene is a gas and an important plant hormone, which can have an adverse effect on quality af potted plants...

  1. OLIGOMERIZATION AND LIQUEFACTION OF ETHYLENE

    African Journals Online (AJOL)

    oligomerize ethylene gas in a packed bed reactor operated at 100-300°C under apressure of 500psi and ... The gas flow was then switched back to N, gas and temperature controller was simultaneously set to the desired reaction temperature. Once the desired .... be considered non-ideal for ethylene oligomerization.

  2. Poly(ethylene oxide monomethyl ether)- block-poly(propylene succinate) Nanoparticles: Synthesis and Characterization, Enzymatic and Cellular Degradation, Micellar Solubilization of Paclitaxel, and in Vitro and in Vivo Evaluation.

    Science.gov (United States)

    Jäger, Alessandro; Jäger, Eliézer; Syrová, Zdeňka; Mazel, Tomas; Kováčik, Lubomír; Raška, Ivan; Höcherl, Anita; Kučka, Jan; Konefal, Rafal; Humajova, Jana; Poučková, Pavla; Štěpánek, Petr; Hrubý, Martin

    2018-04-11

    Polyester-based nanostructures are widely studied as drug-delivery systems due to their biocompatibility and biodegradability. They are already used in the clinic. In this work, we describe a new and simple biodegradable and biocompatible system as the Food and Drug Administration approved polyesters (poly-ε-caprolactone, polylactic acid, and poly(lactic- co-glycolic acid)) for the delivery of the anticancer drug paclitaxel (PTX) as a model drug. A hydrophobic polyester, poly(propylene succinate) (PPS), was prepared from a nontoxic alcohol (propylene glycol) and monomer from the Krebs's cycle (succinic acid) in two steps via esterification and melt polycondensation. Furthermore, their amphiphilic block copolyester, poly(ethylene oxide monomethyl ether)- block-poly(propylene succinate) (mPEO- b-PPS), was prepared by three steps via esterification followed by melt polycondensation and the addition of mPEO to the PPS macromolecules. Analysis of the in vitro cellular behavior of the prepared nanoparticle carriers (NPs) (enzymatic degradation, uptake, localization, and fluorescence resonance energy-transfer pair degradation studies) was performed by fluorescence studies. PTX was loaded to the NPs of variable sizes (30, 70, and 150 nm), and their in vitro release was evaluated in different cell models and compared with commercial PTX formulations. The mPEO- b-PPS copolymer analysis displays glass transition temperature hydrolysis during transport in bloodstream, and simultaneous enzymatic degradability after uptake into the cells. The detailed cytotoxicity in vitro and in vivo tumor efficacy studies have shown the superior efficacy of the NPs compared with PTX and PTX commercial formulations.

  3. Effect of silver ion, carbon dioxide, and oxygen on ethylene action and metabolism

    International Nuclear Information System (INIS)

    Beyer, E.M. Jr.

    1979-01-01

    The relationship between ethylene action and metabolism was investigated in the etiolated pea seedling (Pisum sativum L. cv. Alaska) by inhibiting ethylene action with Ag + , high CO 2 , and low O 2 and then determining if ethylene metabolism was inhibited in a similar manner. Ag + (100 milligrams per liter) was clearly the most potent antiethylene treatment. Ag + pretreatment inhibited the growth retarding action of 0.2 microliters per liter ethylene by 48% and also inhibited the incorporation of 14 C 2 H 4 into pea tips by the same amount. As the ethylene concentration was increased from 0.2 to 30 microliters per liter, the effectiveness of Ag + in reducing ethylene action and metabolism declined in a similar fashion. Although Ag + significantly inhibited the incorporation of 14 C 2 H 4 into tissue metabolites, the oxidation of 14 C 2 H 4 to 14 CO 2 was unaffected. CO 2 (7%) inhibited ethylene-induced growth retardation but its effectiveness diminished at a greater rate than that of Ag + with increasing ethylene concentration. High CO 2 had just the opposite effect of Ag + since it inhibited 14 C 2 H 4 oxidation to 14 CO 2 without affecting tissue incorporation. In contrast to Ag + , CO 2 did not inhibit ethylene action and metabolism to exactly the same extent, and the inhibition of metabolism did not rapidly decline with increasing 14 C 2 H 4 concentration. However, high CO 2 did alter the ratio of 14 C 2 H 4 tissue incorporation to 14 CO 2 production in a manner consistent with changes in ethylene effectiveness. Lowering the O 2 concentration to 5% reduced ethylene-induced growth retardation and inhibited 14 C 2 H 4 tissue incorporation and oxidation to 14 CO 2 by 26 and 45%, respectively. Low O 2 reduced pea seedling growth under these conditions thereby severely limiting its usefulness as a specific antiethylene treatment

  4. Detection of aniline oligomers on polyaniline-gold interface using resonance Raman scattering.

    Science.gov (United States)

    Trchová, Miroslava; Morávková, Zuzana; Dybal, Jiří; Stejskal, Jaroslav

    2014-01-22

    In situ deposited conducting polyaniline films prepared by the oxidation of aniline with ammonium peroxydisulfate in aqueous media of various acidities on gold and silicon supports were characterized by Raman spectroscopy. Enhanced Raman bands were found in the spectra of polyaniline films produced in the solutions of weak acids or in water on gold surface. These bands were weak for the films prepared in solutions of a strong acid on a gold support. The same bands are present in the Raman spectra of the reaction intermediates deposited during aniline oxidation in water or aqueous solutions of weak or strong acids on silicon removed from the reaction mixture at the beginning of the reaction. Such films are formed by aniline oligomers adsorbed on the surface. They were detected on the polyaniline-gold interface using resonance Raman scattering on the final films deposited on gold. The surface resonance Raman spectroscopy of the monolayer of oligomers found in the bulk polyaniline film makes this method advantageous in surface science, with many applications in electrochemistry, catalysis, and biophysical, polymer, or analytical chemistry.

  5. Photooxidation of ethylene over Cu-modified and unmodified silica

    OpenAIRE

    Ichihashi, Yuichi; Matsumura, Yasuyuki

    2003-01-01

    Silica catalyzes photooxidation of ethylene to carbon dioxide and modification of copper on silica results in the lower reaction rate and partial production of ethylene oxide. The reaction does not proceed by the light irradiation through a color filter (λ>280 nm). ESR measurement indicates that radical oxygen species assignable T-shape Si − O3− can be produced on silica by UV irradiation at 77 K. The same species are also found on silica modified with copper by UV irradiation whi...

  6. Action of microwave radiation in emulsion of oil demulsification by copolymers of poly (ethylene oxide-b-propylene oxide); Acao da radiacao micro-ondas na desemulsificacao de emulsoes de petroleo por copolimeros de poli(oxido de etileno-b-oxido de propileno)

    Energy Technology Data Exchange (ETDEWEB)

    Ferreira, Bianca M.S.; Ramalho, Joao B.V.; Guimaraes, Regina C.L.; Guarnieri, Ricardo A. [Petrobras Petroleo Brasileiro - CENPES/TPEP/TPP, Rio de Janeiro, RJ (Brazil)], e-mail: bmachado@petrobras.com.br; Lucas, Elizabete F. [Universidade Federal do Rio de Janeiro, Instituto de Macromoleculas, Laboratorio de Macromoleculas e Coloides na Industria do Petroleo,Rio de Janeiro, RJ (Brazil)], e-mail: elucas@ima.ufrj.br

    2011-07-01

    Emulsions of water-in-petroleum are generally formed during crude oil production. The emulsion needs to be destabilized, along the process in the production units, so as to allow the water-oil separation. This process is accomplished by heating and addition of demulsifier, like poly (ethylene oxide-b-propylene oxide) which promotes the removal of the natural emulsifier from the water droplets interfaces. Normally, the conventional heating is used, but the microwave radiation has been suggested to heat de emulsions. The results obtained in this work show that microwave radiation can really enhance the demulsification rate of petroleum emulsions by gravitational mechanism. It is also shown that demulsification enhancement is greatly related to the selective and higher heating of the water phase induced by the microwave radiation, which causes the lowering of the interfacial film rigidity and the increase of the film drainage, after the demulsifier is added to the dispersed system. It was also observed that the higher the density, viscosity, acidity and asphaltenes content of the crude oil, the lower the demulsification rate. (author)

  7. Hydrogen sulfide alleviates postharvest ripening and senescence of banana by antagonizing the effect of ethylene.

    Directory of Open Access Journals (Sweden)

    Yun Ge

    Full Text Available Accumulating evidence shows that hydrogen sulfide (H2S acts as a multifunctional signaling molecule in plants, whereas the interaction between H2S and ethylene is still unclear. In the present study we investigated the role of H2S in ethylene-promoted banana ripening and senescence by the application of ethylene released from 1.0 g·L-1 ethephon solution or H2S with 1 mM sodium hydrosulfide (NaHS as the donor or in combination. Fumigation with ethylene was found to accelerate banana ripening and H2S treatment effectively alleviated ethylene-induced banana peel yellowing and fruit softening in parallel with decreased activity of polygalacturonase (PG. Ethylene+H2S treatment also delayed the decreases in chlorophyll and total phenolics, and increased the accumulation of flavonoid, whereas decreased the contents of carotenoid, soluble protein in banana peel and reducing sugar in pulp compared with ethylene treatment alone. Besides, ethylene+H2S treatment suppressed the accumulation of superoxide radicals (·O2-, hydrogen peroxide (H2O2 and malondialdehyde (MDA which accumulated highly in ethylene-treated banana peels. Furthermore H2S enhanced total antioxidant capacity in ethylene-treated banana peels with the 2,2'-azobis(3-ethylbenz-thiazoline-6-sulfonic acid (ABTS assay. The result of quantitative real-time PCR showed that the combined treatment of ethylene with H2S down-regulated the expression of ethylene synthesis genes MaACS1, MaACS2 and MaACO1 and pectate lyase MaPL compared with ethylene treatment, while the expression of ethylene receptor genes MaETR, MaERS1 and MaERS2 was enhanced in combination treatment compared with ethylene alone. In all, it can be concluded that H2S alleviates banana fruit ripening and senescence by antagonizing the effect of ethylene through reduction of oxidative stress and inhibition of ethylene signaling pathway.

  8. Hydrogen sulfide alleviates postharvest ripening and senescence of banana by antagonizing the effect of ethylene.

    Science.gov (United States)

    Ge, Yun; Hu, Kang-Di; Wang, Sha-Sha; Hu, Lan-Ying; Chen, Xiao-Yan; Li, Yan-Hong; Yang, Ying; Yang, Feng; Zhang, Hua

    2017-01-01

    Accumulating evidence shows that hydrogen sulfide (H2S) acts as a multifunctional signaling molecule in plants, whereas the interaction between H2S and ethylene is still unclear. In the present study we investigated the role of H2S in ethylene-promoted banana ripening and senescence by the application of ethylene released from 1.0 g·L-1 ethephon solution or H2S with 1 mM sodium hydrosulfide (NaHS) as the donor or in combination. Fumigation with ethylene was found to accelerate banana ripening and H2S treatment effectively alleviated ethylene-induced banana peel yellowing and fruit softening in parallel with decreased activity of polygalacturonase (PG). Ethylene+H2S treatment also delayed the decreases in chlorophyll and total phenolics, and increased the accumulation of flavonoid, whereas decreased the contents of carotenoid, soluble protein in banana peel and reducing sugar in pulp compared with ethylene treatment alone. Besides, ethylene+H2S treatment suppressed the accumulation of superoxide radicals (·O2-), hydrogen peroxide (H2O2) and malondialdehyde (MDA) which accumulated highly in ethylene-treated banana peels. Furthermore H2S enhanced total antioxidant capacity in ethylene-treated banana peels with the 2,2'-azobis(3-ethylbenz-thiazoline-6-sulfonic acid (ABTS) assay. The result of quantitative real-time PCR showed that the combined treatment of ethylene with H2S down-regulated the expression of ethylene synthesis genes MaACS1, MaACS2 and MaACO1 and pectate lyase MaPL compared with ethylene treatment, while the expression of ethylene receptor genes MaETR, MaERS1 and MaERS2 was enhanced in combination treatment compared with ethylene alone. In all, it can be concluded that H2S alleviates banana fruit ripening and senescence by antagonizing the effect of ethylene through reduction of oxidative stress and inhibition of ethylene signaling pathway.

  9. Production of volatiles by the red seaweed Gelidium arbuscula (Rhodophyta): emission of ethylene and dimethyl sulfide.

    Science.gov (United States)

    Garcia-Jimenez, Pilar; Brito-Romano, Olegario; Robaina, Rafael R

    2013-08-01

    The effects of different light conditions and exogenous ethylene on the emission of volatile compounds from the alga Gelidium arbuscula Bory de Saint-Vincent were studied. Special emphasis was placed on the possibility that the emission of ethylene and dimethyl sulfide (DMS) are related through the action of dimethylsulfoniopropionate (DMSP) lyase. The conversion of DMSP to DMS and acrylate, which is catalyzed by DMSP lyase, can indirectly support the synthesis of ethylene through the transformation of acrylate to ethylene. After mimicking the desiccation of G. arbuscula thalli experienced during low tides, the volatile compounds emitted were trapped in the headspace of 2 mL glass vials for 1 h. Two methods based on gas chromatography/mass spectrometry revealed that the range of organic volatile compounds released was affected by abiotic factors, such as the availability and spectral quality of light, salinity, and exogenous ethylene. Amines and methyl alkyl compounds were produced after exposure to white light and darkness but not after exposure to exogenous ethylene or red light. Volatiles potentially associated with the oxidation of fatty acids, such as alkenes and low-molecular-weight oxygenated compounds, accumu-lated after exposure to exogenous ethylene and red light. Ethylene was produced in all treatments, especially after exposure to exogenous ethylene. Levels of DMS, the most abundant sulfur-compound that was emitted in all of the conditions tested, did not increase after incubation with ethylene. Thus, although DMSP lyase is active in G. arbuscula, it is unlikely to contribute to ethylene synthesis. The generation of ethylene and DMS do not appear to be coordinated in G. arbuscula. © 2013 Phycological Society of America.

  10. Stabilization of aqueous dispersions of poly(methacrylic acid)-coated iron oxide nanoparticles by double hydrophilic block polyelectrolyte poly(ethylene oxide)-block-poly(N-methyl-2-vinylpyridinium iodide)

    Czech Academy of Sciences Publication Activity Database

    Wozniak, E.; Špírková, Milena; Šlouf, Miroslav; Garamus, V. M.; Šafaříková, Miroslava; Šafařík, Ivo; Štěpánek, M.

    2017-01-01

    Roč. 514, 5 February (2017), s. 32-37 ISSN 0927-7757 R&D Projects: GA TA ČR(CZ) TE01020118; GA MŠk(CZ) LO1507 Institutional support: RVO:61389013 ; RVO:60077344 Keywords : superparamagnetic iron oxide nanoparticles * polyelectrolytes * SAXS Subject RIV: CD - Macromolecular Chemistry; CD - Macromolecular Chemistry (BC-A) OBOR OECD: Polymer science; Polymer science (BC-A) Impact factor: 2.714, year: 2016

  11. Mass Spectrometric Characterization of Oligomers in Pseudomonas aeruginosa Azurin Solutions

    Czech Academy of Sciences Publication Activity Database

    Sokolová, L.; Williamson, H.; Sýkora, Jan; Hof, Martin; Gray, H. B.; Brutschy, B.; Vlček, Antonín

    2011-01-01

    Roč. 115, č. 16 (2011), s. 4790-4800 ISSN 1520-6106 R&D Projects: GA MŠk(CZ) ME10124; GA MŠk(CZ) LC06063 Institutional research plan: CEZ:AV0Z40400503 Keywords : mass spectrometry * oligomers * pseudomonas aeruginosa azurin solutions Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 3.696, year: 2011

  12. Coronavirus nucleocapsid proteins assemble constitutively in high molecular oligomers

    NARCIS (Netherlands)

    Cong, Yingying; Kriegenburg, Franziska; de Haan, Cornelis A. M.; Reggiori, Fulvio

    2017-01-01

    Coronaviruses (CoV) are enveloped viruses and rely on their nucleocapsid N protein to incorporate the positive-stranded genomic RNA into the virions. CoV N proteins form oligomers but the mechanism and relevance underlying their multimerization remain to be fully understood. Using in vitro pull-down

  13. Threshold photoelectron--photonion coincidence mass spectrometric study of ethylene and ethylene-d4

    International Nuclear Information System (INIS)

    Stockbauer, R.; Inghram, M.G.

    1975-01-01

    Experimental curves have been obtained for the fragmentation of ethylene and ethylene-d 4 ions as a function of the internal energy of those ions using threshold photoelectron--photoion coincidence mass spectrometry. The results are compared with the previous results of photoionization mass spectrometry, He I photoelectron--photoion coicidence, charge exchange experiments, and with quasiequilibrium theory (QET) calculations. The discrepancies between results of these previous experiments and QET calculations do not appear in the present data. It is suggested that ion--molecule reactions competing with charge exchange has led to erroneous conclusions in the interpretation of the charge exchange data. It is concluded that QET does describe the fragmentation of ethylene and ethylene-d 4 within the limits of the data and calculations available. The secondary ion fragmentation C 2 H 4 + → C 2 H 3 + +H → C 2 H 2 + +2H is discussed in detail with regard to the C 2 H 3 + fragment ion internal energy distribution

  14. Reductive transformation and inhibitory effect of ethylene under methanogenic conditions in peat-soil

    DEFF Research Database (Denmark)

    Elsgaard, Lars

    2013-01-01

    Ethylene (C2H4), which is a potent gaseous plant hormone, has often been found to accumulate in anoxic soils where pathways of anaerobic C2H4 oxidation are so far unknown and other C2H4 transformation processes are uncommon. The present study shows that ethylene was reduced almost...... stoichiometrically (89–92%) to ethane (C2H6) in peat-soil microcosms incubated under methanogenic conditions. Methanogenesis started after a prolonged anoxic lag-phase (>29 weeks) where added ethylene prevailed despite the availability of nitrate (NO3−) as an alternative electron acceptor. Methanogenesis, as well...... as ethylene reduction to ethane, was inhibited by 90% at 1% oxygen. Likewise, methanogenesis and ethane formation was gradually inhibited (to a similar extent) by increasing ethylene concentrations above 0.2%; this inhibition eventually reached 90–95% at 2.2–4.5% C2H4. The present results extend the known...

  15. Polyaniline: Aniline oxidation with strong and weak oxidants under various acidity

    Energy Technology Data Exchange (ETDEWEB)

    Bláha, Michal, E-mail: blaha@imc.cas.cz [Institute of Macromolecular Chemistry, Academy of Sciences of the Czech Republic, 162 06 Prague 6 (Czech Republic); Trchová, Miroslava; Bober, Patrycja; Morávková, Zuzana [Institute of Macromolecular Chemistry, Academy of Sciences of the Czech Republic, 162 06 Prague 6 (Czech Republic); Prokeš, Jan [Charles University, Faculty of Mathematics and Physics, 180 00 Prague 8 (Czech Republic); Stejskal, Jaroslav [Institute of Macromolecular Chemistry, Academy of Sciences of the Czech Republic, 162 06 Prague 6 (Czech Republic)

    2017-06-15

    Aniline was oxidized with three strong inorganic oxidants (ammonium peroxydisulfate, cerium(IV) sulfate, potassium dichromate), two weak inorganic oxidants (iron(III) chloride, silver nitrate), and one organic oxidant (p-benzoquinone) in aqueous solutions of methanesulfonic acid (MSA) of various concentration. Whereas oxidation of aniline with ammonium peroxydisulfate yielded high-molecular-weight conducting polyaniline (PANI) in the whole acidity range, the oxidation with cerium(IV) sulfate led also to a single product close to PANI with considerably lower molecular weight and lower conductivity. Potassium dichromate gave PANI only at high concentration of MSA. The use of iron(III) chloride yielded composite mixtures of PANI and low-molecular-weight aniline oligomers. The oxidation of aniline with silver nitrate led to composites of silver and an organic part, which was constituted either by aniline oligomers or conducting polyaniline or both. p-Benzoquinone as oxidant produced mainly aniline oligomers with poor conductivity and 2,5-dianilino-p-benzoquinone-like structure detected in FTIR and Raman spectra when oxidation proceeded with weak oxidants. A general model of oxidation with strong and weak oxidants was formulated. - Highlights: • Comparison of aniline oxidation with oxidants of different redox potential. • UV–vis, FTIR and Raman spectroscopies combined with size-exclusion chromatography. • The contents of polymer and oligomers were analyzed and discussed. • General model of aniline oxidation with strong and weak oxidants was formulated.

  16. Ethylene-producing bacteria that ripen fruit.

    Science.gov (United States)

    Digiacomo, Fabio; Girelli, Gabriele; Aor, Bruno; Marchioretti, Caterina; Pedrotti, Michele; Perli, Thomas; Tonon, Emil; Valentini, Viola; Avi, Damiano; Ferrentino, Giovanna; Dorigato, Andrea; Torre, Paola; Jousson, Olivier; Mansy, Sheref S; Del Bianco, Cristina

    2014-12-19

    Ethylene is a plant hormone widely used to ripen fruit. However, the synthesis, handling, and storage of ethylene are environmentally harmful and dangerous. We engineered E. coli to produce ethylene through the activity of the ethylene-forming enzyme (EFE) from Pseudomonas syringae. EFE converts a citric acid cycle intermediate, 2-oxoglutarate, to ethylene in a single step. The production of ethylene was placed under the control of arabinose and blue light responsive regulatory systems. The resulting bacteria were capable of accelerating the ripening of tomatoes, kiwifruit, and apples.

  17. Method to separate deuterium isotopes using ethylene and ethylene dichloride

    International Nuclear Information System (INIS)

    Benson, S.W.

    1979-01-01

    The separation of deuterium by the dissociation of ethylene vinyl chloride, 1,2-dichloro-ethanes or propylene with the help of intensive, matched infrared lasers enables a relatively good yield if operated on a large scale, e.g. in refineries with large through-put. The deuterium from the laser photolysis of ethylene and vinyl chloride is found in the acetylene formed, which has to be separated off and processed. When using dichloroehtane, the deuterium is found in the vinal chloride formed. The methods are briefly described. (UWI) [de

  18. Ethylene and 1-MCP regulate major volatile biosynthetic pathways in apple fruit.

    Science.gov (United States)

    Yang, Xiaotang; Song, Jun; Du, Lina; Forney, Charles; Campbell-Palmer, Leslie; Fillmore, Sherry; Wismer, Paul; Zhang, Zhaoqi

    2016-03-01

    The effects of ethylene and 1-methylcyclopropene (1-MCP) on apple fruit volatile biosynthesis and gene expression were investigated. Statistical analysis identified 17 genes that changed significantly in response to ethylene and 1-MCP treatments. Genes encoding branched-chain amino acid aminotransferase (BCAT), aromatic amino acid aminotransferase (ArAT) and amino acid decarboxylases (AADC) were up-regulated during ripening and further enhanced by ethylene treatment. Genes related to fatty acid synthesis and metabolism, including acyl-carrier-proteins (ACPs), malonyl-CoA:ACP transacylase (MCAT), acyl-ACP-desaturase (ACPD), lipoxygenase (LOX), hydroperoxide lyase (HPL), alcohol dehydrogenase (ADH), pyruvate decarboxylase (PDC2), β-oxidation, acyl-CoA synthetase (ACS), enoyl-CoA hydratase (ECHD), acyl-CoA dehydrogenase (ACAD), and alcohol acyltransferases (AATs) also increased during ripening and in response to ethylene treatment. Allene oxide synthase (AOS), alcohol dehydrogenase 1 (ADH1), 3-ketoacyl-CoA thiolase and branched-chain amino acid aminotransferase 2 (BCAT2) decreased in ethylene-treated fruit. Treatment with 1-MCP and ethylene generally produced opposite effects on related genes, which provides evidence that regulation of these genes is ethylene dependent. Crown Copyright © 2015. Published by Elsevier Ltd. All rights reserved.

  19. Involvement of ethylene in gibberellic acid-induced sulfur assimilation, photosynthetic responses, and alleviation of cadmium stress in mustard.

    Science.gov (United States)

    Masood, Asim; Khan, M Iqbal R; Fatma, Mehar; Asgher, Mohd; Per, Tasir S; Khan, Nafees A

    2016-07-01

    The role of gibberellic acid (GA) or sulfur (S) in stimulation of photosynthesis is known. However, information on the involvement of ethylene in GA-induced photosynthetic responses and cadmium (Cd) tolerance is lacking. This work shows that ethylene is involved in S-assimilation, photosynthetic responses and alleviation of Cd stress by GA in mustard (Brassica juncea L.). Plants grown with 200 mg Cd kg(-1) soil were less responsive to ethylene despite high ethylene evolution and showed photosynthetic inhibition. Plants receiving 10 μM GA spraying plus 100 mg S kg(-1) soil supplementation exhibited increased S-assimilation and photosynthetic responses under Cd stress. Application of GA plus S decreased oxidative stress of plants grown with Cd and limited stress ethylene formation to the range suitable for promoting sulfur use efficiency (SUE), glutathione (GSH) production and photosynthesis. The role of ethylene in GA-induced S-assimilation and reversal of photosynthetic inhibition by Cd was substantiated by inhibiting ethylene biosynthesis with the use of aminoethoxyvinylglycine (AVG). The suppression of S-assimilation and photosynthetic responses by inhibiting ethylene in GA plus S treated plants under Cd stress indicated the involvement of ethylene in GA-induced S-assimilation and Cd stress alleviation. The outcome of the study is important to unravel the interaction between GA and ethylene and their role in Cd tolerance in plants. Copyright © 2016 Elsevier Masson SAS. All rights reserved.

  20. Kinetic modelling of radiochemical ageing of ethylene-propylene copolymers

    International Nuclear Information System (INIS)

    Colin, Xavier; Richaud, Emmanuel; Verdu, Jacques; Monchy-Leroy, Carole

    2010-01-01

    A non-empirical kinetic model has been built for describing the general trends of radiooxidation kinetics of ethylene-propylene copolymers (EPR) at low γ dose rate and low temperature. It is derived from a radical chain oxidation mechanism composed of 30 elementary reactions: 19 relative to oxidation of methylene and methyne units plus 11 relative to their eventual cooxidation. The validity of this model has been already checked successfully elsewhere for one homopolymer: polyethylene (PE) (; ). In the present study, it is now checked for polypropylene (PP) and a series of three EPR differing essentially by their mole fraction of ethylene (37%, 73% and 86%) and their crystallinity degree (0%, 5% and 26%). Predicted values of radiation-chemical yields are in good agreement with experimental ones published in the last half past century.

  1. Charge transfer in conjugated oligomers encapsulated into carbon nanotubes

    Energy Technology Data Exchange (ETDEWEB)

    Almadori, Y.; Alvarez, L.; Michel, T.; Le Parc, R.; Bantignies, J.L.; Hermet, P.; Sauvajol, J.L. [Laboratoire Charles Coulomb UMR 5521, Universite Montpellier 2, 34095 Montpellier (France); Laboratoire Charles Coulomb UMR 5521, CNRS, 34095 Montpellier (France); Arenal, R. [Laboratoire d' Etude des Microstructures, CNRS-ONERA, 92322 Chatillon (France); Laboratorio de Microscopias Avanzadas, Instituto de Nanociencia de Aragon, U. Zaragoza, 50018 Zaragoza (Spain); Babaa, R. [Laboratoire de Chimie des Surfaces et Interfaces, CEA, IRAMIS, SPCSI, 91191 Gif-sur-Yvette Cedex (France); Chemical Engineering Department, University of Technology PETRONAS, UTP, Ipoh-Perak (Malaysia); Jouselme, B.; Palacin, S. [Laboratoire de Chimie des Surfaces et Interfaces, CEA, IRAMIS, SPCSI, 91191 Gif-sur-Yvette Cedex (France)

    2011-11-15

    This study deals with a hybrid system consisting in quaterthiophene derivative encapsulated inside single-walled and multi-walled carbon nanotubes. Investigations of the encapsulation step are performed by transmission electron microscopy. Raman spectroscopy data point out different behaviors depending on the laser excitation energy with respect to the optical absorption of quaterthiophene. At low excitation energy (far from the oligomer resonance window) there is no significant modification of the Raman spectra before and after encapsulation. By contrast, at high excitation energy (close to the oligomer resonance window), Raman spectra exhibit a G-band shift together with an important RBM intensity loss, suggesting a significant charge transfer between the inserted molecule and the host nanotubes. Those results suggest a photo induced process leading to a significant charge transfer. (Copyright copyright 2011 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  2. 21 CFR 573.440 - Ethylene dichloride.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 6 2010-04-01 2010-04-01 false Ethylene dichloride. 573.440 Section 573.440 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) ANIMAL... Additive Listing § 573.440 Ethylene dichloride. The food additive ethylene dichloride may be safely used in...

  3. 21 CFR 173.230 - Ethylene dichloride.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Ethylene dichloride. 173.230 Section 173.230 Food... Solvents, Lubricants, Release Agents and Related Substances § 173.230 Ethylene dichloride. A tolerance of 30 parts per million is established for ethylene dichloride in spice oleoresins when present therein...

  4. Some biological actions of PEG-conjugated RNase A oligomers

    Czech Academy of Sciences Publication Activity Database

    Poučková, P.; Škvor, J.; Gotte, G.; Vottariello, F.; Slavík, Tomáš; Matoušek, Josef; Laurents, D. V.; Libonati, M.; Souček, J.

    2006-01-01

    Roč. 53, č. 1 (2006), s. 79-85 ISSN 0028-2685 R&D Projects: GA ČR GA523/04/0755; GA MZd NR8233 Grant - others:Spanish Ministerio de Ciencia y Technologia BQU2003-05227 Institutional research plan: CEZ:AV0Z50450515 Keywords : RNase A oligomers * polyethylene glycol conjugates * anti-tumour activity Subject RIV: EB - Genetics ; Molecular Biology Impact factor: 1.247, year: 2006

  5. Photoinduced Cross-Linking of Dynamic Poly(disulfide) Films via Thiol Oxidative Coupling.

    Science.gov (United States)

    Feillée, Noémi; Chemtob, Abraham; Ley, Christian; Croutxé-Barghorn, Céline; Allonas, Xavier; Ponche, Arnaud; Le Nouen, Didier; Majjad, Hicham; Jacomine, Léandro

    2016-01-01

    Initially developed as an elastomer with an excellent record of barrier and chemical resistance properties, poly(disulfide) has experienced a revival linked to the dynamic nature of the S-S covalent bond. A novel photobase-catalyzed oxidative polymerization of multifunctional thiols to poly(disulfide) network is reported. Based solely on air oxidation, the single-step process is triggered by the photodecarboxylation of a xanthone acetic acid liberating a strong bicyclic guanidine base. Starting with a 1 μm thick film based on trithiol poly(ethylene oxide) oligomer, the UV-mediated oxidation of thiols to disulfides occurs in a matter of minutes both selectively, i.e., without overoxidation, and quantitatively as assessed by a range of spectroscopic techniques. Thiolate formation and film thickness determine the reaction rates and yield. Spatial control of the photopolymerization serves to generate robust micropatterns, while the reductive cleavage of S-S bridges allows the recycling of 40% of the initial thiol groups. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  6. Microstructure, optical, and electrochromic properties of sol-gel nanoporous tungsten oxide films

    Science.gov (United States)

    Djaoued, Yahia; Ashrit, P. V.; Badilescu, S.; Bruning, R.

    2003-08-01

    Porous tungsten oxide films have been prepared by a nonhydrolitic sol-gel method using poly(ethylene glycol) (PEG) as a structure directing agent. The method entails the hydrolysis of an ethanolic solution of tungsten ethoxide (formed by the reaction of WCl6 with ethanol) followed by condensation and polymerization at the PEG-tungsten oxide oligometers interface. A highly porous WO3 framework was obtained after PEG was burned off by calcination at a relativley low temperature. AFM images of the films treated thermally show an ordered material rather than microscopic particulates. Both fibrilar nanostructures and striped phase can be obtained via this approach, depending on the concentration of PEG in the coating solution. XRD data from the fibrils indicate that they are crystalline with very small crystals, whereas the striped phases obtained with 20% PEG correspond to two crystalline phases, one, the stoichiometric WO3 and the other one an oxygen deficient phase, containing larger crystals (~28 nm). The results show that PEG promotes the formation of oxygen deficient phases and delays crystallization. Compared to WO3 with no PEG, the optical and electrochromic properties of the macroporous tungsten oxide films appear to be significantly improved. The formation of organized nanostructures is tentatively accounted for by the strong hydrogen bonding interactions between PEG and the tungsten oxide oligomers.

  7. α-Synuclein oligomers and clinical implications for Parkinson disease

    Science.gov (United States)

    Kalia, Lorraine V.; Kalia, Suneil K.; McLean, Pamela J.; Lozano, Andres M.; Lang, Anthony E.

    2012-01-01

    Protein aggregation within the central nervous system has been recognized as a defining feature of neurodegenerative diseases since the early 20th century. Since that time, there has been a growing list of neurodegenerative disorders, including Parkinson disease, which are characterized by inclusions of specific pathogenic proteins. This has led to the long-held dogma that these characteristic protein inclusions, which are composed of large insoluble fibrillar protein aggregates and visible by light microscopy, are responsible for cell death in these diseases. However, the correlation between protein inclusion formation and cytotoxicity is inconsistent suggesting another form of the pathogenic proteins may be contributing to neurodegeneration. There is emerging evidence implicating soluble oligomers, smaller protein aggregates not detectable by conventional microscopy, as potential culprits in the pathogenesis of neurodegenerative diseases. The protein α-synuclein is well recognized to contribute to the pathogenesis of Parkinson disease and is the major component of Lewy bodies and Lewy neurites. However, α-synuclein also forms oligomeric species with certain conformations being toxic to cells. The mechanisms by which these α-synuclein oligomers cause cell death are being actively investigated as they may provide new strategies for diagnosis and treatment of Parkinson disease and related disorders. Here we review the possible role of α-synuclein oligomers in cell death in Parkinson disease and discuss the potential clinical implications. PMID:23225525

  8. Interchain interactions in charged diacetylenic oligomers carrying bulk substituents revisited

    International Nuclear Information System (INIS)

    Ottonelli, M.; Izzo, G.M.M.; Comoretto, D.; Musso, G.F.; Dellepiane, G.

    2006-01-01

    We are studying how the electronic properties of an aggregate, built with conjugated oligomers carrying bulk substituents, are affected by intermolecular interactions. In this paper we apply the CEO (Collective Electronic Oscillator) method, on the basis of the semiempirical INDO/S Hamiltonian, to compute the electronic density matrix modifications following the photon absorption in a doubly charged cluster of two units of a fully carbazolyl-substituted oligodiacetylene tetramer, taken as a model system. The picture that had emerged from our previous calculations based on the less sophisticated CIS (Configuration Interaction including Singles) approach is seen to be confirmed. Despite the large separation between the backbones, a through-space charge transfer occurs between the two oligomers due to the fact that the excess charge, contrary to what is generally believed, is not localized on the conjugated backbone, but is spread out over the carbazolyl moieties of the charged molecule. Consideration of this kind of interaction improves the theoretical results obtained for the isolated charged oligomer chain, and aids in better explaining some features of the experimental photoinduced spectra of the corresponding polymer

  9. Synthesis of soybean oil-based thiol oligomers.

    Science.gov (United States)

    Wu, Jennifer F; Fernando, Shashi; Weerasinghe, Dimuthu; Chen, Zhigang; Webster, Dean C

    2011-08-22

    Industrial grade soybean oil (SBO) and thiols were reacted to generate thiol-functionalized oligomers via a thermal, free radical initiated thiol-ene reaction between the SBO double bond moieties and the thiol functional groups. The effect of the reaction conditions, including thiol concentration, catalyst loading level, reaction time, and atmosphere, on the molecular weight and the conversion to the resultant soy-thiols were examined in a combinatorial high-throughput fashion using parallel synthesis, combinatorial FTIR, and rapid gel permeation chromatography (GPC). High thiol functionality and concentration, high thermal free radical catalyst concentration, long reaction time, and the use of a nitrogen reaction atmosphere were found to favor fast consumption of the SBO, and produced high molecular weight products. The thiol conversion during the reaction was inversely affected by a high thiol concentration, but was favored by a long reaction time and an air reaction atmosphere. These experimental observations were explained by the initial low affinity of the SBO and thiol, and the improved affinity between the generated soy-thiol oligomers and unreacted SBO during the reaction. The synthesized soy-thiol oligomers can be used for renewable thiol-ene UV curable materials and high molecular solids and thiourethane thermal cure materials. Copyright © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  10. Aβ42 oligomers selectively disrupt neuronal calcium release.

    Science.gov (United States)

    Lazzari, Cristian; Kipanyula, Maulilio J; Agostini, Mario; Pozzan, Tullio; Fasolato, Cristina

    2015-02-01

    Accumulation of amyloid-β (Aβ) peptides correlates with aging and progression of Alzheimer's disease (AD). Aβ peptides, which cause early synaptic dysfunctions, spine loss, and memory deficits, also disturb intracellular Ca(2+) homeostasis. By cytosolic and endoplasmic reticulum Ca(2+) measurements, we here define the short-term effects of synthetic Aβ42 on neuronal Ca(2+) dynamics. When applied acutely at submicromolar concentration, as either oligomers or monomers, Aβ42 did not cause Ca(2+) release or Ca(2+) influx. Similarly, 1-hour treatment with Aβ42 modified neither the resting cytosolic Ca(2+) level nor the long-lasting Ca(2+) influx caused by KCl-induced depolarization. In contrast, Aβ42 oligomers, but not monomers, significantly altered Ca(2+) release from stores with opposite effects on inositol 1,4,5-trisphosphate (IP3)- and caffeine-induced Ca(2+) mobilization without alteration of the total store Ca(2+) content. Ca(2+) dysregulation by Aβ42 oligomers involves metabotropic glutamate receptor 5 and requires network activity and the intact exo-endocytotic machinery, being prevented by tetrodotoxin and tetanus toxin. These findings support the idea that Ca(2+) store dysfunction is directly involved in Aβ42 neurotoxicity and represents a potential therapeutic target in AD-like dementia. Copyright © 2015 Elsevier Inc. All rights reserved.

  11. Development of CuO–ethylene glycol nanofluids for efficient energy management: Assessment of potential for energy recovery

    International Nuclear Information System (INIS)

    Allen Zennifer, M.; Manikandan, S.; Suganthi, K.S.; Leela Vinodhan, V.; Rajan, K.S.

    2015-01-01

    Highlights: • CuO–ethylene glycol nanofluids prepared and characterized. • Maximum thermal conductivity enhancement of 14.1% at 50 °C for 1 vol% nanofluid. • Heat transfer performance in correspondence with improved transport properties. • 11.8% enhancement in heat transfer rate for 1 vol% nanofluid. - Abstract: Ethylene glycol (EG) plays an important role as coolant in sub-artic and artic regions owing to its low freezing point. However one of the limitations of ethylene glycol for energy management is its low thermal conductivity, which can be improved by addition of nanoparticles. In the present work, cupric oxide nanoparticles have been synthesized followed by dispersion in ethylene glycol through extended probe ultrasonication without addition of chemical dispersing agent. Temperature dependency of thermal conductivity of 1 vol% CuO–ethylene glycol nanofluid exhibited a minimum at a critical temperature corresponding to lower thickness of interfacial layers and negligible Brownian motion. The influence of liquid layering on thermal conductivity was predominant at temperatures below critical temperature leading to higher thermal conductivity at lower temperature. Brownian motion-induced microconvection resulted in thermal conductivity increase with temperature above the critical temperature. About 14.1% enhancement in thermal conductivity was obtained at 50 °C for 1 vol% CuO–ethylene glycol nanofluid. The viscosity of CuO–ethylene glycol nanofluid was lower than the viscosity of ethylene glycol at temperatures below 50 °C and 120 °C for 1 vol% and 0.5 vol% CuO–ethylene glycol nanofluids. Our data reveal that the CuO–ethylene glycol nanofluids are better coolants than ethylene glycol for transient cooling under constant heat flux conditions with 11.8% enhancement in heat transfer rate for 1 vol% CuO–ethylene glycol nanofluid. Hence the use of ethylene glycol-based nanofluids is a promising approach for energy management.

  12. Haemoglobin modulates salicylate and jasmonate/ethylene-mediated resistance mechanisms against pathogens

    DEFF Research Database (Denmark)

    Mur, Luis A J; Sivakumaran, Anushen; Mandon, Julien

    2012-01-01

    Nitric oxide (NO) plays a role in defence against hemibiotrophic pathogens mediated by salicylate (SA) and also necrotrophic pathogens influenced by jasmonate/ethylene (JA/Et). This study examined how NO-oxidizing haemoglobins (Hb) encoded by GLB1, GLB2, and GLB3 in Arabidopsis could influence both...

  13. Stimulation of lettuce seed germination by ethylene.

    Science.gov (United States)

    Abeles, F B; Lonski, J

    1969-02-01

    Ethylene increased the germination of freshly imbibed lettuce (Lactuca sativa L. var. Grand Rapids) seeds. Seeds receiving either red or far-red light or darkness all showed a positive response to the gas. However, ethylene was apparently without effect on dormant seeds, those which failed to germinate after an initial red or far-red treatment. Carbon dioxide, which often acts as a competitive inhibitor of ethylene, failed to clearly reverse ethylene-enhanced seed germination. While light doubled ethylene production from the lettuce seeds, its effect was not mediated by the phytochrome system since both red and far-red light had a similar effect.

  14. The radiation crosslinking of ethylene copolymers

    International Nuclear Information System (INIS)

    Burns, N.M.

    1979-01-01

    The enhanced radiation crosslinking tendency of ethylene-vinyl acetate and ethylene-ethyl acrylate copolymers over ethylene homopolymer is proportional to the comonomer content. This is caused by an increase in the amorphous polymer content and by structure-related factors. The copolymers crosslink by a random process that for ethylene-vinyl acetate copolymer involves some crosslinking through the acetoxy group of the comonomer. While knowledge of the process for the crosslinking of ethylene-ethyl acrylate copolymer is less certain, it is currently believed to occur primarily at the branch point on the polymer backbone. Data relating comonomer content and the molecular weight of the copolymers to the radiation crosslinking levels realized were developed to aid in resin selection by the formulator. Triallyl cyanurate cure accelerator was found to be less effective in ethylene-vinyl acetate copolymer than in homopolymer and to have no effect on gel development in ethylene-ethyl acrylate copolymer. (author)

  15. Effects of lattice fluctuations on electronic transmission in metal/conjugated-oligomer/metal structures

    International Nuclear Information System (INIS)

    Yu, Z.G.; Smith, D.L.; Saxena, A.; Bishop, A.R.

    1997-01-01

    The electronic transmission across metal/conjugated-oligomer/metal structures in the presence of lattice fluctuations is studied for short oligomer chains. The lattice fluctuations are approximated by static white noise disorder. Resonant transmission occurs when the energy of an incoming electron coincides with a discrete electronic level of the oligomer. The corresponding transmission peak diminishes in intensity with increasing disorder strength. Because of disorder there is an enhancement of the electronic transmission for energies that lie within the electronic gap of the oligomer. If fluctuations are sufficiently strong, a transmission peak within the gap is found at the midgap energy E=0 for degenerate conjugated oligomers (e.g., trans-polyacetylene) and E≠0 for AB-type degenerate oligomers. These results can be interpreted in terms of soliton-antisoliton states created by lattice fluctuations. copyright 1997 The American Physical Society

  16. Characterization of radiation modified κ-carrageenan oligomers for bio-based materials development

    International Nuclear Information System (INIS)

    Abad, Lucille V.; Relleve, Lorna S.; Aranilla, Charito T.; Racadio, Darwin T.; Dela Rosa, Alumanda M.

    2011-01-01

    κ-carrageenan oligomers are known to have several biological activities such as anti-HIV, anti-herpes, antitumor and antioxidant properties. Recent progress in the development of radiation modified κ-carrageenan has resulted in new applications such as plant growth promoter, radiation dose indicator and hydrogels for wound dressing. This presentation would touch on the changes in chemical structure, gelation and conformational transition behavior and molecular size of κ-carrageenan at doses from 0 to 200 kGy and would be correlated to these functions for the development of bio-based materials. Chemical and spectral analyses were carried out using UV-Vis spectroscopy, FT-IR spectroscopy, NMR spectroscopy, reducing sugar analysis, free sulfate and carboxylic acid analysis. The chemical and spectral analyses of the radiolytic products indicated increasing reducing sugars, carbonyl, carboxylic acids, and sulfates with increasing doses which reached a maximum level at a certain dose depending on the irradiation condition. Values were very much lower in solid irradiation (in vacuum and in air) as compared to aqueous irradiation. NMR data also revealed an intact structure of the oligomer irradiated at 100 kGy in the specific fraction that contains an Mw = (3-10) kDa. κ-carrageenan oligomers exhibited antioxidant properties as determined by hydroxyl radical scavenging activity, reducing power and DPPH radical scavenging capacity assay. The degree of oxidative inhibition increased with increasing dose which can be attributed to higher reducing sugar. Dynamic light scattering (DLS) experiments showed that a dose of up to 50 kGy, sol-gelation transition was still observed. Beyond 50 kGy, no gelation took place, instead appearance of fast relax-carrageenan mode in characteristic decay time function was observed at doses of (75-150) kGy. Optimum peak intensity was found at 100 kGy (mol wt. 5-10 kDa) which coincides with the optimum plant growth promoter effect in κ

  17. A hydrogel biosensor for high selective and sensitive detection of amyloid-beta oligomers

    Directory of Open Access Journals (Sweden)

    Sun LP

    2018-02-01

    Full Text Available Liping Sun,1 Yong Zhong,1 Jie Gui,1 Xianwu Wang,1 Xiaorong Zhuang,2 Jian Weng1 1Key Laboratory of Biomedical Engineering of Fujian Province, Research Center of Biomedical Engineering of Xiamen, Department of Biomaterials, College of Materials, Xiamen University, 2Department of Neurology, The Affiliated Zhongshan Hospital of Xiamen University, Xiamen, People’s Republic of China Background: Alzheimer’s disease (AD is a neurodegenerative disorder characterized by progressive cognitive and memory impairment. It is the most common neurological disease that causes dementia. Soluble amyloid-beta oligomers (AβO in blood or cerebrospinal fluid (CSF are the pathogenic biomarker correlated with AD. Methods: A simple electrochemical biosensor using graphene oxide/gold nanoparticles (GNPs hydrogel electrode was developed in this study. Thiolated cellular prion protein (PrPC peptide probe was immobilized on GNPs of the hydrogel electrode to construct an AβO biosensor. Electrochemical impedance spectroscopy was utilized for AβO analysis. Results: The specific binding between AβO and PrPC probes on the hydrogel electrode resulted in an increase in the electron-transfer resistance. The biosensor showed high specificity and sensitivity for AβO detection. It could selectively differentiate AβO from amyloid-beta (Aβ monomers or fibrils. Meanwhile, it was highly sensitive to detect as low as 0.1 pM AβO in artificial CSF or blood plasma. The linear range for AβO detection is from 0.1 pM to 10 nM. Conclusion: This biosensor could be used as a cost-effective tool for early diagnosis of AD due to its high electrochemical performance and bionic structure. Keywords: Alzheimer’s disease, amyloid-beta oligomer, graphene, gold nanoparticles, biosensor

  18. A Gas Chromatographic System for the Detection of Ethylene Gas Using Ambient Air as a Carrier Gas.

    Science.gov (United States)

    Zaidi, Nayyer Abbas; Tahir, Muhammad Waseem; Vellekoop, Michael J; Lang, Walter

    2017-10-07

    Ethylene gas is a naturally occurring gas that has an influence on the shelf life of fruit during their transportation in cargo ships. An unintentional exposure of ethylene gas during transportation results in a loss of fruit. A gas chromatographic system is presented here for the detection of ethylene gas. The gas chromatographic system was assembled using a preconcentrator, a printed 3D printed gas chromatographic column, a humidity sensor, solenoid valves, and an electrochemical ethylene gas sensor. Ambient air was used as a carrier gas in the gas chromatographic system. The flow rate was fixed to 10 sccm. It was generated through a mini-pump connected in series with a mass flow controller. The metal oxide gas sensor is discussed with its limitation in ambient air. The results show the chromatogram obtained from metal oxide gas sensor has low stability, drifts, and has uncertain peaks, while the chromatogram from the electrochemical sensor is stable and precise. Furthermore, ethylene gas measurements at higher ppb concentration and at lower ppb concentration were demonstrated with the electrochemical ethylene gas sensor. The system separates ethylene gas and humidity. The chromatograms obtained from the system are stable, and the results are 1.2% repeatable in five similar measurements. The statistical calculation of the gas chromatographic system shows that a concentration of 2.3 ppb of ethylene gas can be detected through this system.

  19. Quantitative Ethylene Measurements with MOx Chemiresistive Sensors at Different Relative Air Humidities

    Directory of Open Access Journals (Sweden)

    Matic Krivec

    2015-11-01

    Full Text Available The sensitivity of two commercial metal oxide (MOx sensors to ethylene is tested at different relative humidities. One sensor (MiCS-5914 is based on tungsten oxide, the other (MQ-3 on tin oxide. Both sensors were found to be sensitive to ethylene concentrations down to 10 ppm. Both sensors have significant response times; however, the tungsten sensor is the faster one. Sensor models are developed that predict the concentration of ethylene given the sensor output and the relative humidity. The MQ-3 sensor model achieves an accuracy of ±9.2 ppm and the MiCS-5914 sensor model predicts concentration to ±7.0 ppm. Both sensors are more accurate for concentrations below 50 ppm, achieving ±6.7 ppm (MQ-3 and 5.7 ppm (MiCS-5914.

  20. Inhibition of ethylene production by cobaltous ion

    International Nuclear Information System (INIS)

    Lau, O.L; Yang, S.F.

    1976-01-01

    The effect of Co 2+ on ethylene production by mung bean (Phaseolus aureus Roxb.) and by apple tissues was studied. Co 2+ , depending on concentrations applied, effectively inhibited ethylene production by both tissues. It also strongly inhibited the ethylene production induced by IAA, kinetin, IAA plus kinetin, Ca 2+ , kinetin plus Ca 2+ , or Cu 2+ treatments in mung bean hypocotyl segments. While Co 2+ greatly inhibited ethylene production, it had little effect on the respiration of apple tissue, indicating that Co 2+ does not exert its inhibitory effect as a general metabolic inhibitor. Ni 2+ , which belongs to the same group as Co 2+ in the periodic table, also markedly curtailed both the basal and the induced ethylene production by apple and mung bean hypocotyl tissues. In a system in which kinetin and Ca 2+ were applied together, kinetin greatly enhanced Ca 2+ uptake, thus enhancing ethylene production. Co 2+ , however, slightly inhibited the uptake of Ca 2+ but appreciably inhibited ethylene production, either in the presence or in the absence of kinetin. Tracer experiments using apple tissue indicated that Co 2+ strongly inhibited the in vivo conversion of L-[U-- 14 C]methionine to 14 C-ethylene. These data suggested that Co 2+ inhibited ethylene production by inhibiting the conversion of methionine to ethylene, a common step which is required for ethylene formation by higher plants. Co 2+ is known to promote elongation, leaf expansion, and hook opening in excised plant parts in response to applied auxins or cytokinins.Since ethylene is known to inhibit those growth phenomena, it is suggested that Co 2+ exerts its promotive effect, at least in part, by inhibiting ethylene formation

  1. Fibril specific, conformation dependent antibodies recognize a generic epitope common to amyloid fibrils and fibrillar oligomers that is absent in prefibrillar oligomers

    Directory of Open Access Journals (Sweden)

    Rasool Suhail

    2007-09-01

    Full Text Available Abstract Background Amyloid-related degenerative diseases are associated with the accumulation of misfolded proteins as amyloid fibrils in tissue. In Alzheimer disease (AD, amyloid accumulates in several distinct types of insoluble plaque deposits, intracellular Aβ and as soluble oligomers and the relationships between these deposits and their pathological significance remains unclear. Conformation dependent antibodies have been reported that specifically recognize distinct assembly states of amyloids, including prefibrillar oligomers and fibrils. Results We immunized rabbits with a morphologically homogeneous population of Aβ42 fibrils. The resulting immune serum (OC specifically recognizes fibrils, but not random coil monomer or prefibrillar oligomers, indicating fibrils display a distinct conformation dependent epitope that is absent in prefibrillar oligomers. The fibril epitope is also displayed by fibrils of other types of amyloids, indicating that the epitope is a generic feature of the polypeptide backbone. The fibril specific antibody also recognizes 100,000 × G soluble fibrillar oligomers ranging in size from dimer to greater than 250 kDa on western blots. The fibrillar oligomers recognized by OC are immunologically distinct from prefibrillar oligomers recognized by A11, even though their sizes overlap broadly, indicating that size is not a reliable indicator of oligomer conformation. The immune response to prefibrillar oligomers and fibrils is not sequence specific and antisera of the same specificity are produced in response to immunization with islet amyloid polypeptide prefibrillar oligomer mimics and fibrils. The fibril specific antibodies stain all types of amyloid deposits in human AD brain. Diffuse amyloid deposits stain intensely with anti-fibril antibody although they are thioflavin S negative, suggesting that they are indeed fibrillar in conformation. OC also stains islet amyloid deposits in transgenic mouse models of type

  2. Influence of oxygen concentration on ethylene removal using dielectric barrier discharge

    Science.gov (United States)

    Takahashi, Katsuyuki; Motodate, Takuma; Takaki, Koichi; Koide, Shoji

    2018-01-01

    Ethylene gas is decomposed using a dielectric barrier discharge plasma reactor for long-period preservation of fruits and vegetables. The oxygen concentration in ambient gas is varied from 2 to 20% to simulate the fruit and vegetable transport container. The experimental results show that the efficiency of ethylene gas decomposition increases with decreasing oxygen concentration. The reactions of ethylene molecules with ozone are analyzed by Fourier transform infrared spectrometry. The analysis results show that the oxidization process by ozone is later than that by oxygen atoms. The amount of oxygen atoms that contribute to ethylene removal increases with decreasing oxygen concentration because the reaction between oxygen radicals and oxygen molecules is suppressed at low oxygen concentrations. Ozone is completely removed and the energy efficiency of C2H4 removal is increased using manganese dioxide as a catalyst.

  3. Structural Transitions of Solvent-Free Oligomer-Grafted Nanoparticles

    KAUST Repository

    Chremos, Alexandros

    2011-09-01

    Novel structural transitions of solvent-free oligomer-grafted nanoparticles are investigated by using molecular dynamics simulations of a coarse-grained bead-spring model. Variations in core size and grafting density lead to self-assembly of the nanoparticles into a variety of distinct structures. At the boundaries between different structures, the nanoparticle systems undergo thermoreversible transitions. This structural behavior, which has not been previously reported, deviates significantly from that of simple liquids. The reversible nature of these transitions in solvent-free conditions offers new ways to control self-assembly of nanoparticles at experimentally accessible conditions. © 2011 American Physical Society.

  4. Expression of enzymes in yeast for lignocellulose derived oligomer CBP

    Science.gov (United States)

    McBride, John E.; Wiswall, Erin; Shikhare, Indraneel; Xu, Haowen; Thorngren, Naomi; Hau, Heidi H.; Stonehouse, Emily

    2017-08-29

    The present invention provides a multi-component enzyme system that hydrolyzes hemicellulose oligomers from hardwood which can be expressed, for example, in yeast such as Saccharomyces cerevisiae. In some embodiments, this invention provides for the engineering of a series of biocatalysts combining the expression and secretion of components of this enzymatic system with robust, rapid xylose utilization, and ethanol fermentation under industrially relevant process conditions for consolidated bioprocessing. In some embodiments, the invention utilizes co-cultures of strains that can achieve significantly improved performance due to the incorporation of additional enzymes in the fermentation system.

  5. The mechanism of ethylene signaling induced by endophytic fungus Gilmaniella sp. AL12 mediating sesquiterpenoids biosynthesis in Atractylodes lancea

    Directory of Open Access Journals (Sweden)

    Jie eYuan

    2016-03-01

    Full Text Available Ethylene, the first known gaseous phytohormone, is involved in plant growth, development as well as responses to environmental signals. However, limited information is available on the role of ethylene in endophytic fungi induced secondary metabolites biosynthesis. Atractylodes lancea is a traditional Chinese herb, and its quality depends on the main active compounds sesquiterpenoids. This work showed that the endophytic fungus Gilmaniella sp. AL12 induced ethylene production in Atractylodes lancea. Pre-treatment of plantlets with ethylene inhibiter aminooxyacetic acid (AOA suppressed endophytic fungi induced accumulation of ethylene and sesquiterpenoids. Plantlets were further treated with AOA, salicylic acid (SA biosynthesis inhibitor paclobutrazol (PAC, jasmonic acid inhibitor ibuprofen (IBU, hydrogen peroxide (H2O2 scavenger catalase (CAT, nitric oxide (NO-specific scavenger 2-(4-Carboxyphenyl-4,4,5,5-tetramethylimidazoline-1-oxyl-3-oxide potassium salt (cPTIO. With endophytic fungi inoculation, IBU or PAC did not inhibit ethylene production, and JA and SA generation were suppressed by AOA, showing that ethylene may act as an upstream signal of JA and SA pathway. With endophytic fungi inoculation, CAT or cPTIO suppressed ethylene production, and H2O2 or NO generation was not affected by 1-aminocyclopropane-1-carboxylic acid (ACC, showing that ethylene may act as a downstream signal of H2O2 and NO pathway. Then, plantlets were treated with ethylene donor ACC, JA, SA, H2O2, NO donor sodium nitroprusside (SNP. Exogenous ACC could trigger JA and SA generation, whereas exogenous JA or SA did not affect ethylene production, and the induced sesquiterpenoids accumulation triggered by ACC was partly suppressed by IBU and PAC, showing that ethylene acted as an upstream signal of JA and SA pathway. Exogenous ACC did not affect H2O2 or NO generation, whereas exogenous H2O2 and SNP induced ethylene production, and the induced sesquiterpenoids

  6. Method of deuterium isotope separation using ethylene and ethylene dichloride

    International Nuclear Information System (INIS)

    Benson, S.W.

    1982-01-01

    Compounds enriched in deuterium may be obtained from ethylene, vinyl chloride, 1,2-dichloroethane, or propylene by laser isotope separation. Normal molecules of these organic compounds are exposed to infrared laser radiation of a suitable wavelength. Substantially all of the deuterium-containing molecules exposed to the laser can be selectively dissociated and the deuterium-containing products separated from the starting material and other reaction products. The deuterium-containing molecules can be burned to form water with an enriched deuterium content, or pyrolized to form hydrogen gas enriched in deuterium

  7. Effect of alcohol vapor treatment on electrical and optical properties of poly(3,4-ethylene dioxythiophene):poly(styrene sulfonate) films for indium tin oxide-free organic light-emitting diodes

    Energy Technology Data Exchange (ETDEWEB)

    Fallahzadeh, Ali, E-mail: afa.phy@gmail.com; Saghaei, Jaber; Yousefi, Mohammad Hassan

    2014-11-30

    Graphical abstract: - Highlights: • A simple alcohol vapor treatment (AVT) technique was applied to enhance the conductivity of PEDOT:PSS films. • Alcohols with one OH group can improve conductivity of PEDOT:PSS films by this technique. • Mechanism of conductivity enhancement of PEDOT:PSS films by AVT method was explained. • ITO-free OLEDs were fabricated using highly conductive AVT PEDOT:PSS films standalone anode. - Abstract: A simple alcohol vapor treatment (AVT) technique was proposed to improve the conductivity of poly(3,4-ethylene dioxythiophene):poly(styrene sulfonate) (PEDOT:PSS) films. In this technique, various alcohols, i.e. methanol, ethanol, 2-propanol and ethylene glycol, were applied to treat the surface of the films formed and then they were annealed. The sheet resistance of PEDOT:PSS films was significantly reduced from 130 kΩ/sq to 60 Ω/sq when treated with methanol vapor. The investigation of the vertical resistance of the films showed that the sample treated with methanol vapor displayed the lowest resistance as well. The mechanism of conductivity enhancement of PEDOT:PSS films through AVT method was explained by surface phase images, UV and IR spectra of PEDOT:PSS films. Optical transmittance spectrum of treated films exhibited that AVT has even enhanced the optical transmittance slightly. Improvement in the morphology, electrical and optical properties of PEDOT:PSS films prompted their applications as a transparent anode in the fabrication of ITO-free organic light-emitting diodes (OLEDs). The OLED manufactured based on methanol-treated PEDOT:PSS films demonstrated the highest luminance.

  8. Charge Delocalization in Oligomers of Poly(2,5-bis(3-alkylthiophene-2-yl)thieno[3,2-b]thiophene), PBTTT

    KAUST Repository

    Zhang, Yuexing

    2016-04-25

    We investigate theoretically charge delocalization in radical-cations, i.e., positive polarons, formed on oligomer chains of poly(2,5-bis(3-alkylthiophene-2-yl)thieno[3,2-b]thiophene), PBTTT. We use non-empirically tuned range-separated density functionals (TRS-DFT), including LC-ωPBE, LC-BLYP, and ωB97XD. We consider the evolution with oligomer length of the molecular geometric and electronic structures, optical absorption features, and spin densities. The TRS-DFT results indicate that a positive polaron can delocalize ideally over some 10 thiophene rings when the backbone is non-planar and up to 14 rings for a backbone forced to be completely planar. Interestingly, up to six polarons can co-exist side-by-side in a hexamer (which contains 24 thiophene rings), which is consistent with the highest degrees of doping (oxidation) experimentally achievable in polythiophene derivatives.

  9. Charge Delocalization in Oligomers of Poly(2,5-bis(3-alkylthiophene-2-yl)thieno[3,2-b]thiophene), PBTTT

    KAUST Repository

    Zhang, Yuexing; Steyrleuthner, Robert; Bredas, Jean-Luc

    2016-01-01

    We investigate theoretically charge delocalization in radical-cations, i.e., positive polarons, formed on oligomer chains of poly(2,5-bis(3-alkylthiophene-2-yl)thieno[3,2-b]thiophene), PBTTT. We use non-empirically tuned range-separated density functionals (TRS-DFT), including LC-ωPBE, LC-BLYP, and ωB97XD. We consider the evolution with oligomer length of the molecular geometric and electronic structures, optical absorption features, and spin densities. The TRS-DFT results indicate that a positive polaron can delocalize ideally over some 10 thiophene rings when the backbone is non-planar and up to 14 rings for a backbone forced to be completely planar. Interestingly, up to six polarons can co-exist side-by-side in a hexamer (which contains 24 thiophene rings), which is consistent with the highest degrees of doping (oxidation) experimentally achievable in polythiophene derivatives.

  10. Ethylene- and diethylene glycol metabolism, toxicity and treatment

    International Nuclear Information System (INIS)

    Wiener, H.L.

    1986-01-01

    Each year numerous men and domestic animals suffer from ethylene glycol (EG) poisoning. The present approach to treating EG poisoning by administering ethanol is aimed at preventing the oxidation of EG to glycolate, the toxic mediator. When treatment is delayed or the amount of EG consumed is large, successful treatment is rarely obtained, since the concentration of glycolate becomes excessive. In an effort to develop a better approach to treating EG poisoning, studies were conducted to determine the feasibility of using pig liver glycolic acid oxidase (GAO) as a means of enzyme therapy in male rats receiving EG. Pig liver GAO was active in vitro in rat blood, oxidizing glycolate to glyoxylate. When injected intravenously into male rats, GAO had an approximate half-life of twenty five minutes and its elimination followed first order kinetics. Despite activity in vitro, native pig liver GAO did not display detectable activity in vivo. Diethylene glycol (DEG) when ingested also results in toxicity. The metabolism and toxicity of DEG was investigated in male Wistar rats using [ 14 C]-DEG synthesized from [U- 14 C]-EG and ethylene oxide and purified by high performance liquid chromatography. (2-Hydroxyethoxy)acetic acid (HEAA) was identified as the major product of DEG oxidation. These results suggest that the treatment of DEG poisoning should follow the same regimen as treatment for EG poisoning

  11. Amyloid oligomer structure characterization from simulations: A general method

    Energy Technology Data Exchange (ETDEWEB)

    Nguyen, Phuong H., E-mail: phuong.nguyen@ibpc.fr [Laboratoire de Biochimie Théorique, UPR 9080, CNRS Université Denis Diderot, Sorbonne Paris Cité IBPC, 13 rue Pierre et Marie Curie, 75005 Paris (France); Li, Mai Suan [Institute of Physics, Polish Academy of Sciences, Al. Lotnikow 32/46, 02-668 Warsaw (Poland); Derreumaux, Philippe, E-mail: philippe.derreumaux@ibpc.fr [Laboratoire de Biochimie Théorique, UPR 9080, CNRS Université Denis Diderot, Sorbonne Paris Cité IBPC, 13 rue Pierre et Marie Curie, 75005 Paris (France); Institut Universitaire de France, 103 Bvd Saint-Germain, 75005 Paris (France)

    2014-03-07

    Amyloid oligomers and plaques are composed of multiple chemically identical proteins. Therefore, one of the first fundamental problems in the characterization of structures from simulations is the treatment of the degeneracy, i.e., the permutation of the molecules. Second, the intramolecular and intermolecular degrees of freedom of the various molecules must be taken into account. Currently, the well-known dihedral principal component analysis method only considers the intramolecular degrees of freedom, and other methods employing collective variables can only describe intermolecular degrees of freedom at the global level. With this in mind, we propose a general method that identifies all the structures accurately. The basis idea is that the intramolecular and intermolecular states are described in terms of combinations of single-molecule and double-molecule states, respectively, and the overall structures of oligomers are the product basis of the intramolecular and intermolecular states. This way, the degeneracy is automatically avoided. The method is illustrated on the conformational ensemble of the tetramer of the Alzheimer's peptide Aβ{sub 9−40}, resulting from two atomistic molecular dynamics simulations in explicit solvent, each of 200 ns, starting from two distinct structures.

  12. Organization of the resting TCR in nanoscale oligomers.

    Science.gov (United States)

    Schamel, Wolfgang W A; Alarcón, Balbino

    2013-01-01

    Despite the low affinity of the T-cell antigen receptor (TCR) for its peptide/major histocompatibility complex (pMHC) ligand, T cells are very sensitive to their antigens. This paradox can be resolved if we consider that the TCR may be organized into pre-existing oligomers or nanoclusters. Such structures could improve antigen recognition by increasing the functional affinity (avidity) of the TCR-pMHC interaction and by allowing cooperativity between individual TCRs. Up to approximately 20 TCRs become tightly apposed in these nanoclusters, often in a linear manner, and such structures could reflect a relatively generalized phenomenon: the non-random concentration of membrane receptors in specific areas of the plasma membrane known as protein islands. The association of TCRs into nanoclusters can explain the enhanced kinetics of the pMHC-TCR interaction in two dimensional versus three dimensional systems, but also their existence calls for a revision of the TCR triggering models based on pMHC-induced TCR clustering. Interestingly, the B-cell receptor and the FcεRI have also been shown to form nanoclusters, suggesting that the formation of pre-existing receptor oligomers could be widely used in the immune system. © 2012 John Wiley & Sons A/S. Published by Blackwell Publishing Ltd.

  13. Supersymmetry theory of microphase separation in homopolymer-oligomer mixtures

    International Nuclear Information System (INIS)

    Olemskoi, Alexander; Krakovsky, Ivan; Savelyev, Alexey

    2004-01-01

    The mesoscopic structure of periodically alternating layers of stretched homopolymer chains surrounded by perpendicularly oriented oligomeric tails is studied for systems with both strong (ionic) and weak (hydrogen) interactions. We focus on the consideration of the distribution of oligomers along the homopolymer chains that is described by the effective equation of motion with the segment number playing the role of imaginary time. The supersymmetry technique is developed to consider associative hydrogen bonding, self-action effects, inhomogeneity, and temperature fluctuations in the oligomer distribution. Making use of the self-consistent approach allows one to explain experimentally observed temperature dependence of the structure period and the order-disorder transition temperature and period as functions of the oligomeric fraction for systems with different bonding strengths. A whole set of parameters of the model used is found for strong, intermediate, and weak coupled systems being Poly (4-vinyl pyridine)-dodecyl benzene sulfonic acid [P4VP-(DBSA) x ], P4VP-[Zn(DBS) 2 ] x , and P4VP- 3-pentadecyl Phenol x , respectively. A passage from the former two to the latter is shown to cause a crucial decrease in the magnitude of both parameters of hydrogen bonding and self-action, as well as the order-disorder transition temperature

  14. Dietary flavanols and procyanidin oligomers from cocoa (Theobroma cacao) inhibit platelet function.

    Science.gov (United States)

    Murphy, Karen J; Chronopoulos, Andriana K; Singh, Indu; Francis, Maureen A; Moriarty, Helen; Pike, Marilyn J; Turner, Alan H; Mann, Neil J; Sinclair, Andrew J

    2003-06-01

    Flavonoids may be partly responsible for some health benefits, including antiinflammatory action and a decreased tendency for the blood to clot. An acute dose of flavanols and oligomeric procyanidins from cocoa powder inhibits platelet activation and function over 6 h in humans. This study sought to evaluate whether 28 d of supplementation with cocoa flavanols and related procyanidin oligomers would modulate human platelet reactivity and primary hemostasis and reduce oxidative markers in vivo. Thirty-two healthy subjects were assigned to consume active (234 mg cocoa flavanols and procyanidins/d) or placebo (cocoa flavanols and procyanidins/d) tablets in a blinded parallel-designed study. Platelet function was determined by measuring platelet aggregation, ATP release, and expression of activation-dependent platelet antigens by using flow cytometry. Plasma was analyzed for oxidation markers and antioxidant status. Plasma concentrations of epicatechin and catechin in the active group increased by 81% and 28%, respectively, during the intervention period. The active group had significantly lower P selectin expression and significantly lower ADP-induced aggregation and collagen-induced aggregation than did the placebo group. Plasma ascorbic acid concentrations were significantly higher in the active than in the placebo group (P antioxidant status did not change in either group. Cocoa flavanol and procyanidin supplementation for 28 d significantly increased plasma epicatechin and catechin concentrations and significantly decreased platelet function. These data support the results of acute studies that used higher doses of cocoa flavanols and procyanidins.

  15. Ethylene Glycol Adsorption and Reaction over CeOX(111) Thin Films

    Energy Technology Data Exchange (ETDEWEB)

    T Chen; D Mullins

    2011-12-31

    This study reports the interaction of ethylene glycol with well-ordered CeO{sub x}(111) thin film surfaces. Ethylene glycol initially adsorbs on fully oxidized CeO{sub 2}(111) and reduced CeO{sub 2-x}(111) through the formation of one C-O-Ce bond and then forms a second alkoxy bond after annealing. On fully oxidized CeO{sub 2}(111) both recombination of ethylene glycol and water desorption occur at low temperature leaving stable -OCH{sub 2}CH{sub 2}O- (ethylenedioxy) intermediates and oxygen vacancies on the surface. This ethylenedioxy intermediate goes through C-C bond scission to produce formate species which then react to produce CO and CO{sub 2}. The formation of water results in the reduction of the ceria. On a reduced CeO{sub 2-x}(111) surface the reaction selectivity shifts toward a dehydration process. The ethylenedioxy intermediate decomposes by breaking a C-O bond and converts into an enolate species. Similar to the reaction of acetaldehyde on reduced CeO{sub 2-x}(111), the enolate reacts to produce acetaldehyde, acetylene, and ethylene. The loss of O from ethylene glycol leads to a small amount of oxidation of the reduced ceria.

  16. Photo-electron spectroscopy study of energy levels in conjugated oligomers

    NARCIS (Netherlands)

    Veenstra, SC; Heeres, A; Stalmach, U; Wildeman, J; Hadziioannou, G; Sawatzky, GA; Jonkman, HT; Moss, SC

    2002-01-01

    We report on the valence orbital structure of poly(para-phenylenevinylene) (PPV)-like oligomers. We studied these molecules as isolated oligomers in the gas phase, as well as in thin films deposited on metal substrates. We use a simple model based on a previously reported Hamiltonian that accurately

  17. Tau oligomers impair memory and induce synaptic and mitochondrial dysfunction in wild-type mice

    Directory of Open Access Journals (Sweden)

    Jackson George R

    2011-06-01

    Full Text Available Abstract Background The correlation between neurofibrillary tangles of tau and disease progression in the brains of Alzheimer's disease (AD patients remains an area of contention. Innovative data are emerging from biochemical, cell-based and transgenic mouse studies that suggest that tau oligomers, a pre-filament form of tau, may be the most toxic and pathologically significant tau aggregate. Results Here we report that oligomers of recombinant full-length human tau protein are neurotoxic in vivo after subcortical stereotaxic injection into mice. Tau oligomers impaired memory consolidation, whereas tau fibrils and monomers did not. Additionally, tau oligomers induced synaptic dysfunction by reducing the levels of synaptic vesicle-associated proteins synaptophysin and septin-11. Tau oligomers produced mitochondrial dysfunction by decreasing the levels of NADH-ubiquinone oxidoreductase (electron transport chain complex I, and activated caspase-9, which is related to the apoptotic mitochondrial pathway. Conclusions This study identifies tau oligomers as an acutely toxic tau species in vivo, and suggests that tau oligomers induce neurodegeneration by affecting mitochondrial and synaptic function, both of which are early hallmarks in AD and other tauopathies. These results open new avenues for neuroprotective intervention strategies of tauopathies by targeting tau oligomers.

  18. Amyloid-β oligomer detection by ELISA in cerebrospinal fluid and brain tissue.

    Science.gov (United States)

    Bruggink, Kim A; Jongbloed, Wesley; Biemans, Elisanne A L M; Veerhuis, Rob; Claassen, Jurgen A H R; Kuiperij, H Bea; Verbeek, Marcel M

    2013-02-15

    Amyloid-β (Aβ) deposits are important pathological hallmarks of Alzheimer's disease (AD). Aβ aggregates into fibrils; however, the intermediate oligomers are believed to be the most neurotoxic species and, therefore, are of great interest as potential biomarkers. Here, we have developed an enzyme-linked immunosorbent assay (ELISA) specific for Aβ oligomers by using the same capture and (labeled) detection antibody. The ELISA predominantly recognizes relatively small oligomers (10-25 kDa) and not monomers. In brain tissue of APP/PS1 transgenic mice, we found that Aβ oligomer levels increase with age. However, for measurements in human samples, pretreatment to remove human anti-mouse antibodies (HAMAs) was required. In HAMA-depleted human hippocampal extracts, the Aβ oligomer concentration was significantly increased in AD compared with nondemented controls. Aβ oligomer levels could also be quantified in pretreated cerebrospinal fluid (CSF) samples; however, no difference was detected between AD and control groups. Our data suggest that levels of small oligomers might not be suitable as biomarkers for AD. In addition, we demonstrate the importance of avoiding HAMA interference in assays to quantify Aβ oligomers in human body fluids. Copyright © 2012 Elsevier Inc. All rights reserved.

  19. Charge Separation and Recombination in Small Band Gap Oligomer-Fullerene Triads

    NARCIS (Netherlands)

    Karsten, Bram P.; Bouwer, Ricardo K. M.; Hummelen, Jan C.; Williams, Rene M.; Janssen, Rene A. J.

    2010-01-01

    Synthesis and photophysics of a series of thiophene-thienopyrazine small band gap oligomers end-capped at both ends with C(60) are presented In these triads a photoinduced electron transfer reaction occurs between the oligomer as a donor and the fullerene as an acceptor Femtosecond photoinduced

  20. Theory of microphase separation in homopolymer-oligomer mixtures

    Energy Technology Data Exchange (ETDEWEB)

    Olemskoi, Alexander [Department of Physical Electronics, Sumy State University, Rimskii-Korsakov St. 2, 40007 Sumy (Ukraine)]. E-mail: alex@ufn.ru; Savelyev, Alexey [Department of Chemistry, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599-3290 (United States)]. E-mail: alexsav@unc.edu

    2005-11-01

    This work starts with the review of theoretical methods proposed, during past decades, for description of phase behavior in different polymer systems, involving variety of linear polymers (regular and polydisperse block (co)polymers, random polymers) and the polymer systems with non-covalent bonds of different strength. Microphase separation (MS) into different ordered mesophases is known to be the principal property of such systems. It is shown that most of the theoretical approaches proposed for description of the MS are based on the simple random phase approximation (RPA). It turns out, however, that mean field RPA method applied to description of the systems with non-covalent bonds does not provide the whole picture of MS. We show that the problem here arises when one treats both Flory-Huggins non-associated interactions and non-covalent bonds (hydrogen, ionic) within the unified RPA scheme, which is obviously rough for description of the latter type of interactions. Such a theory was developed in a few recent papers for the systems involving weak hydrogen bonds between homopolymer chains and the low molecular weight oligomers (surfactants). However, it leaves some experimental data unaccounted. The purpose of this review is to consider more detailed theory which is able to explain not only all the experimental data for the above systems but also to take into account the strength variation of non-bonding interactions. In particular, we consider the strong ionic interactions, weak hydrogen bonding, and the interactions of intermediate strength between polymer chain and short oligomers within our unifying theory. To develop such a description in a self-consistent way we propose to use a general field theory of stochastic systems. The mesoscopic (lamellar) structure of the periodically alternating layers of stretched homopolymer chains surrounded by perpendicularly oriented oligomeric tails is studied for the systems with both strong (ionic) and weak (hydrogen