Stress-corrosion cracking of indium tin oxide coated polyethylene terephthalate for flexible optoelectronic devices

International Nuclear Information System (INIS)

Sierros, Konstantinos A.; Morris, Nicholas J.; Ramji, Karpagavalli; Cairns, Darran R.

2009-01-01

Stress corrosion cracking of transparent conductive layers of indium tin oxide (ITO), sputtered on polyethylene terephthalate (PET) substrates, is an issue of paramount importance in flexible optoelectronic devices. These components, when used in flexible device stacks, can be in contact with acid containing pressure-sensitive adhesives or with conductive polymers doped in acids. Acids can corrode the brittle ITO layer, stress can cause cracking and delamination, and stress-corrosion cracking can cause more rapid failure than corrosion alone. The combined effect of an externally-applied mechanical stress to bend the device and the corrosive environment provided by the acid is investigated in this work. We show that acrylic acid which is contained in many pressure-sensitive adhesives can cause corrosion of ITO coatings on PET. We also investigate and report on the combined effect of external mechanical stress and corrosion on ITO-coated PET composite films. Also, it is shown that the combination of stress and corrosion by acrylic acid can cause ITO cracking to occur at stresses less than a quarter of those needed for failure with no corrosion. In addition, the time to failure, under ∼ 1% tensile strain can reduce the total time to failure by as much as a third

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 ...

Magnetron sputtered transparent conductive zinc-oxide stabilized amorphous indium oxide thin films on polyethylene terephthalate substrates at ambient temperature

International Nuclear Information System (INIS)

Yan, Y.; Zhang, X.-F.; Ding, Y.-T.

2013-01-01

Amorphous transparent conducting zinc-oxide stabilized indium oxide thin films, named amorphous indium zinc oxide (a-IZO), were deposited by direct current magnetron sputtering at ambient temperature on flexible polyethylene terephthalate substrates. It has been demonstrated that the electrical resistivity could attain as low as ∼ 5 × 10 −4 Ω cm, which was noticeably lower than amorphous indium tin oxide films prepared at the same condition, while the visible transmittance exceeded 84% with the refractive index of 1.85–2.00. In our experiments, introduction of oxygen gas appeared to be beneficial to the improvement of the transparency and electrical conductivity. Both free carrier absorption and indirect transition were observed and Burstein–Moss effect proved a-IZO to be a degenerated amorphous semiconductor. However, the linear relation between the optical band gap and the band tail width which usually observed in covalent amorphous semiconductor such as a-Si:H was not conserved. Besides, porosity could greatly determine the resistivity and optical constants for the thickness variation at this deposition condition. Furthermore, a broad photoluminescence peak around 510 nm was identified when more than 1.5 sccm oxygen was introduced. - Highlights: ► Highly conducting amorphous zinc-oxide stabilized indium oxide thin films were prepared. ► The films were fabricated on polyethylene terephthalate at ambient temperature. ► Introduction of oxygen can improve the transparency and electrical conductivity. ► The linear relation between optical band gap and band tail width was not conserved

Effect of oral administration of terephthalic acid on testicular functions of rats

International Nuclear Information System (INIS)

Cui Lunbiao; Dai Guidong; Xu Lichun; Wang Shouling; Song Ling; Zhao Renzhen; Xiao Hang; Zhou Jianwei; Wang Xinru

2004-01-01

To investigate the toxic effect of terephthalic acid (TPA) on testicular functions of rats, male Sprague-Dawley rats were orally administered TPA in diet at the levels 0 (control), 0.2, 1 and 5% for 90 days. Testicular functions were assessed by histopathology, testicular sperm head counts, daily sperm production, sperm motility (measured by computer-assisted sperm analysis, CASA), biochemical indices (marker testicular enzymes), and serum testosterone. Oral feeding with terephthalic acid did not cause body and testes weight loss in TPA-treated groups. Histopathologically, damages of spermatogenic cells and Sertoli cells were observed by electron microscope, testicular sperm head counts, daily sperm production, and activities of sorbitol dehydrogenase (SDH) were decreased significantly in the 5% TPA group. The motility of spermatozoa was reduced significantly in all treated groups, which was correlated with administration doses. Serum testosterone concentrations were not declined in treated groups. In conclusion, TPA can cause impairment of testicular functions. The primary sites of action may be spermatogenic cells and Sertoli cells. The results of the present study provide first information of TPA on testicular functions in male rats

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

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.

UV-induced graft polymerization of acrylic acid in the sub-micronchannels of oxidized PET track-etched membrane

Science.gov (United States)

Korolkov, Ilya V.; Mashentseva, Anastassiya A.; Güven, Olgun; Taltenov, Abzal A.

2015-12-01

In this article, we report on functionalization of track-etched membrane based on poly(ethylene terephthalate) (PET TeMs) oxidized by advanced oxidation systems and by grafting of acrylic acid using photochemical initiation technique for the purpose of increasing functionality thus expanding its practical application. Among advanced oxidation processes (H2O2/UV) system had been chosen to introduce maximum concentration of carboxylic acid groups. Benzophenone (BP) photo-initiator was first immobilized on the surfaces of cylindrical pores which were later filled with aq. acrylic acid solution. UV-irradiation from both sides of PET TeMs has led to the formation of grafted poly(acrylic acid) (PAA) chains inside the membrane sub-micronchannels. Effect of oxygen-rich surface of PET TeMs on BP adsorption and subsequent process of photo-induced graft polymerization of acrylic acid (AA) were studied by ESR. The surface of oxidized and AA grafted PET TeMs was characterized by UV-vis, ATR-FTIR, XPS spectroscopies and by SEM.

THERMAL DEGRADATION OF THERMOTROPIC LIQUID CRYSTALLINE TERPOLYESTERS BASED ON VANILLIC ACID, p-HYDROXYBENZOIC ACID AND POLY(ETHYLENE TEREPHTHALATE)

Institute of Scientific and Technical Information of China (English)

LI Xingui; HUANG Meirong; GUAN Guihe; SUN Tong

1993-01-01

Nine thermotropic liquid crystalline terpolyesters based on vanillic acid(V), p-hydroxybenzoic acid(H) and poly(ethylene terephthalate)(E) were investigated by thermogravimetry to ascertain their thermostability and the kinetic parameters for thermal degradation. Overall activation energy data of the degradation had been calculated over the range 5～70% weight loss. The temperatures and the activation energy of the degradation lie in the ranges of 384～394 ℃ at a heating rate of 1 ℃/min and 176～205 KJ/mol at the weight loss of 5%, respectively, which suggests that the terpolyesters have good thermostability.

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...

A bacterium that degrades and assimilates poly(ethylene terephthalate).

Science.gov (United States)

Yoshida, Shosuke; Hiraga, Kazumi; Takehana, Toshihiko; Taniguchi, Ikuo; Yamaji, Hironao; Maeda, Yasuhito; Toyohara, Kiyotsuna; Miyamoto, Kenji; Kimura, Yoshiharu; Oda, Kohei

2016-03-11

Poly(ethylene terephthalate) (PET) is used extensively worldwide in plastic products, and its accumulation in the environment has become a global concern. Because the ability to enzymatically degrade PET has been thought to be limited to a few fungal species, biodegradation is not yet a viable remediation or recycling strategy. By screening natural microbial communities exposed to PET in the environment, we isolated a novel bacterium, Ideonella sakaiensis 201-F6, that is able to use PET as its major energy and carbon source. When grown on PET, this strain produces two enzymes capable of hydrolyzing PET and the reaction intermediate, mono(2-hydroxyethyl) terephthalic acid. Both enzymes are required to enzymatically convert PET efficiently into its two environmentally benign monomers, terephthalic acid and ethylene glycol. Copyright © 2016, American Association for the Advancement of Science.

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

工业PTA氧化过程中4-CBA浓度的模糊神经网络模型%Fuzzy Neural Network Model of 4-CBA Concentration for Industrial Purified Terephthalic Acid Oxidation Process

Institute of Scientific and Technical Information of China (English)

刘瑞兰; 苏宏业; 牟盛静; 贾涛; 陈渭泉; 褚健

2004-01-01

A fuzzy neural network (FNN) model is developed to predict the 4-CBA concentration of the oxidation unit in purified terephthalic acid process. Several technologies are used to deal with the process data before modeling.First, a set of preliminary input variables is selected according to prior knowledge and experience. Secondly, a method based on the maximum correlation coefficient is proposed to detect the dead time between the process variables and response variables. Finally, the fuzzy curve method is used to reduce the unimportant input variables. The simulation results based on industrial data show that the relative error range of the FNN model is narrower than that of the American Oil Company (AMOCO) model. Furthermore, the FNN model can predict the trend of the 4-CBA concentration more accurately.

Solvothermal synthesis of uranium(VI) phases with aromatic carboxylate ligands: A dinuclear complex with 4-hydroxybenzoic acid and a 3D framework with terephthalic acid

Energy Technology Data Exchange (ETDEWEB)

Zhang, Yingjie, E-mail: yzx@ansto.gov.au [Australian Nuclear Science and Technology Organisation, Locked Bag 2001, Kirrawee DC, NSW 2232 (Australia); Karatchevtseva, Inna [Australian Nuclear Science and Technology Organisation, Locked Bag 2001, Kirrawee DC, NSW 2232 (Australia); Bhadbhade, Mohan [Mark Wainwright Analytical Centre, University of New South Wales, Kensington, NSW 2052 (Australia); Tran, Toan Trong; Aharonovich, Igor [School of Physics and Advanced Materials, University of Technology Sydney, Ultimo, NSW 2007 (Australia); Fanna, Daniel J.; Shepherd, Nicholas D. [School of Science and Health, Western Sydney University, Locked Bag 1797, Penrith, NSW 2751 (Australia); Lu, Kim [Australian Nuclear Science and Technology Organisation, Locked Bag 2001, Kirrawee DC, NSW 2232 (Australia); Li, Feng [School of Science and Health, Western Sydney University, Locked Bag 1797, Penrith, NSW 2751 (Australia); Lumpkin, Gregory R. [Australian Nuclear Science and Technology Organisation, Locked Bag 2001, Kirrawee DC, NSW 2232 (Australia)

2016-02-15

With the coordination of dimethylformamide (DMF), two new uranium(VI) complexes with either 4-hydroxybenzoic acid (H{sub 2}phb) or terephthalic acid (H{sub 2}tph) have been synthesized under solvothermal conditions and structurally characterized. [(UO{sub 2}){sub 2}(Hphb){sub 2}(phb)(DMF)(H{sub 2}O){sub 3}]·4H{sub 2}O (1) has a dinuclear structure constructed with both pentagonal and hexagonal bipyramidal uranium polyhedra linked through a µ{sub 2}-bridging ligand via both chelating carboxylate arm and alcohol oxygen bonding, first observation of such a coordination mode of 4-hydroxybenzoate for 5 f ions. [(UO{sub 2})(tph)(DMF)] (2) has a three-dimensional (3D) framework built with pentagonal bipyramidal uranium polyhedra linked with µ{sub 4}-terephthalate ligands. The 3D channeled structure is facilitated by the unique carboxylate bonding with nearly linear C–O–U angles and the coordination of DMF molecules. The presence of phb ligands in different coordination modes, uranyl ions in diverse environments and DMF in complex 1, and tph ligand, DMF and uranyl ion in complex 2 has been confirmed by Raman spectroscopy. In addition, their thermal stability and photoluminescence properties have been investigated. - Graphical abstract: With the coordination of dimethylformamide, two new uranyl complexes with either 4-hydroxybenzoate or terephthalate have been synthesized under solvothermal conditions and structurally characterized. - Highlights: • Solvent facilitates the synthesis of two new uranium(VI) complexes. • A dinuclear complex with both penta- and hexagonal bipyramidal uranium polyhedral. • A unique µ{sub 2}-bridging mode of 4-hydroxybenzoate via alcohol oxygen for 5 f ions. • A 3D framework with uranium polyhedra and µ{sub 4}-terephthalate ligands. • Vibration modes and photoluminescence properties are reported.

Electron beam induced modification of poly(ethylene terephthalate) films

International Nuclear Information System (INIS)

Vasiljeva, I.V.; Mjakin, S.V.; Makarov, A.V.; Krasovsky, A.N.; Varlamov, A.V.

2006-01-01

Electron beam processing of poly(ethylene terephthalate) (PET) films is found to promote significant changes in the melting heat, intrinsic viscosity and polymer film-liquid (water, isooctane and toluene) boundary surface tension. These properties are featured with several maximums depending on the absorbed dose and correlating with the modification of PET surface functionality. Studies using adsorption of acid-base indicators and IR-spectroscopy revealed that the increase of PET surface hydrophilicity is determined by the oxidation of methylene and methyne groups. Electron beam treatment of PET films on the surface of N-vinylpyrrolidone aqueous solution provided graft copolymerization with this comonomer at optimum process parameters (energy 700 keV, current 1 mA, absorbed dose 50 kGy)

Electron beam induced modification of poly(ethylene terephthalate) films

Energy Technology Data Exchange (ETDEWEB)

Vasiljeva, I.V. [Technology Center RADIANT, 10, Kurchatova Str., 194223 St. Petersburg (Russian Federation)]. E-mail: radiant@skylink.spb.ru; Mjakin, S.V. [Technology Center RADIANT, 10, Kurchatova Str., 194223 St. Petersburg (Russian Federation); Makarov, A.V. [St.-Petersburg State University of Cinema and Television, 13, ul. Pravdy, 191126 St. Petersburg (Russian Federation); Krasovsky, A.N. [St.-Petersburg State University of Cinema and Television, 13, ul. Pravdy, 191126 St. Petersburg (Russian Federation); Varlamov, A.V. [St.-Petersburg State University of Cinema and Television, 13, ul. Pravdy, 191126 St. Petersburg (Russian Federation)

2006-10-15

Electron beam processing of poly(ethylene terephthalate) (PET) films is found to promote significant changes in the melting heat, intrinsic viscosity and polymer film-liquid (water, isooctane and toluene) boundary surface tension. These properties are featured with several maximums depending on the absorbed dose and correlating with the modification of PET surface functionality. Studies using adsorption of acid-base indicators and IR-spectroscopy revealed that the increase of PET surface hydrophilicity is determined by the oxidation of methylene and methyne groups. Electron beam treatment of PET films on the surface of N-vinylpyrrolidone aqueous solution provided graft copolymerization with this comonomer at optimum process parameters (energy 700 keV, current 1 mA, absorbed dose 50 kGy)

Study of compounds emitted during thermo-oxidative decomposition of polyester fabrics

Directory of Open Access Journals (Sweden)

Dzięcioł Małgorzata

2016-03-01

Full Text Available Compounds emitted during thermo-oxidative decomposition of three commercial polyester fabrics for indoor outfit and decorations (upholstery, curtains were studied. The experiments were carried out in a flow tubular furnace at 600°C in an air atmosphere. During decomposition process the complex mixtures of volatile and solid compounds were emitted. The main volatile products were carbon oxides, benzene, acetaldehyde, vinyl benzoate and acetophe-none. The emitted solid compounds consisted mainly of aromatic carboxylic acids and its derivatives, among which the greatest part took terephthalic acid, monovinyl terephthalate and benzoic acid. The small amounts of polycyclic aromatic hydrocarbons were also emitted. The emission profiles of the tested polyester fabrics were similar. The presence of toxic compounds indicates the possibility of serious hazard for people during fire.

Effects of annealing temperature on mechanical durability of indium-tin oxide film on polyethylene terephthalate substrate

International Nuclear Information System (INIS)

Machinaga, Hironobu; Ueda, Eri; Mizuike, Atsuko; Takeda, Yuuki; Shimokita, Keisuke; Miyazaki, Tsukasa

2014-01-01

Effects of the annealing temperature on mechanical durability of indium-tin oxide (ITO) thin films deposited on polyethylene terephthalate (PET) substrates were investigated. The ITO films were annealed at the range from 150 °C to 195 °C after the DC sputtering deposition for the production of polycrystalline ITO layers on the substrates. The onset strains of cracking in the annealed ITO films were evaluated by the uniaxial stretching tests with electrical resistance measurements during film stretching. The results indicate that the onset strain of cracking in the ITO film is clearly increased by increasing the annealing temperature. The in-situ measurements of the inter-planer spacing of the (222) plane in the crystalline ITO films during film stretching by using synchrotron radiation strongly suggest that the large compressive stress in the ITO film increases the onset strain of cracking in the film. X-ray stress analyses of the annealed ITO films and thermal mechanical analyses of the PET substrates also clarifies that the residual compressive stress in the ITO film is enhanced with increasing the annealing temperature due to the considerably larger shrinkage of the PET substrate. - Highlights: • Indium-tin oxide (ITO) films were deposited on polyethylene terephthalate (PET). • Mechanical durability of the ITO is improved by high temperature post-annealing. • The shrinkage in the PET increases with rising the post-annealing temperature. • The shrinkage of the PET enhances the compressive stress in the ITO film. • Large compressive stress in the ITO film may improve its mechanical durability

Polyesters production from the mixture of phthalic acid, terephthalic and glycerol; Producao de poliesteres a partir da mistura de acido ftalico, tereftalico e glicerol

Energy Technology Data Exchange (ETDEWEB)

Carvalho, A.L.S.; Oliveira, J.C.; Miranda, C.S.; Boaventura, J.S.; Jose, N.M., E-mail: adrianaequfba@gmail.co [Universidade Federal da Bahia (GECIM/UFBA), Salvador, BA (Brazil). Inst. de Quimica. Grupo de Energia e Ciencias dos Materiais; Carvalho, R.F. [Universidade Federal da Bahia (UFBA), Salvador, BA (Brazil). Escola Politecnica. Curso de Mestrado em Engenharia Ambiental Urbana

2010-07-01

Glycerin, a byproduct of biodiesel is currently an environmental and economic problem for producers of this renewable fuel in Brazil and in others parts of the world. In order to offer new proposals for recovery, it is used for the manufacture of polyesters used in applications in diverse areas such as construction and automobile industry. This work reports the production of polymer from the mixture of terephthalic and phthalic acid in three different proportions. The polyesters showed good thermal stability, analyzed by TGA and DSC, with an increase proportional to the terephthalic acid content. The X-ray diffraction patterns show that the samples are semi crystalline polymers. The micrographs indicated the presence of a smoother surface in the polyester that has a larger amount of phthalic acid, as reported in the literature. Therefore, the materials showed good thermal properties and morphological characteristics, so it consists in a new alternative to use glycerin. (author)

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.

The selective recycling of mixed plastic waste of polylactic acid and polyethylene terephthalate by control of process conditions

OpenAIRE

Carné Sánchez, Arnau; Collinson, Simon R.

2011-01-01

The glycolysis of postconsumer polyethylene terephthalate (PET) waste was evaluated with catalysts of zinc acetate, zinc stearate and zinc sulfate, showing that zinc acetate was the most soluble and effective. The chemical recycling by solvolysis of polylactic acid (PLA) and PET waste in either methanol or ethanol was investigated. Zinc acetate as a catalyst was found to be necessary to yield an effective depolymerization of waste PLA giving lactate esters, while with the same reaction condit...

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.

Radiation induced deposition of copper nanoparticles inside the nanochannels of poly(acrylic acid)-grafted poly(ethylene terephthalate) track-etched membranes

Science.gov (United States)

Korolkov, Ilya V.; Güven, Olgun; Mashentseva, Anastassiya A.; Atıcı, Ayse Bakar; Gorin, Yevgeniy G.; Zdorovets, Maxim V.; Taltenov, Abzal A.

2017-01-01

Poly(ethylene terephthalate) PET, track-etched membranes (TeMs) with 400 nm average pore size were UV-grafted with poly(acrylic acid) (PAA) after oxidation of inner surfaces by H2O2/UV system. Carboxylate groups of grafted PAA chains were easily complexed with Cu2+ ions in aqueous solutions. These ions were converted into metallic copper nanoparticles (NPs) by radiation-induced reduction of copper ions in aqueous-alcohol solution by gamma rays in the dose range of 46-250 kGy. Copper ions chelating with -COOH groups of PAA chains grafted on PET TeMs form polymer-metal ion complex that prevent the formation of agglomerates during reduction of copper ions to metallic nanoparticles. The detailed analysis by X-Ray diffraction technique (XRD), transmission electron microscopy (TEM), scanning electron microscopy (SEM) and energy-dispersive X-ray spectroscopy (EDX) confirmed the deposition of copper nanoparticles with the average size of 70 nm on the inner surface of nanochannels of PET TeMs. Samples were also investigated by FTIR, ESR spectroscopies to follow copper ion reduction.

High dimension feature extraction based visualized SOM fault diagnosis method and its application in p-xylene oxidation process☆

Institute of Scientific and Technical Information of China (English)

Ying Tian; Wenli Du; Feng Qian

2015-01-01

Purified terephthalic acid (PTA) is an important chemical raw material. P-xylene (PX) is transformed to terephthalic acid (TA) through oxidation process and TA is refined to produce PTA. The PX oxidation reaction is a complex process involving three-phase reaction of gas, liquid and solid. To monitor the process and to im-prove the product quality, as wel as to visualize the fault type clearly, a fault diagnosis method based on self-organizing map (SOM) and high dimensional feature extraction method, local tangent space alignment (LTSA), is proposed. In this method, LTSA can reduce the dimension and keep the topology information simultaneously, and SOM distinguishes various states on the output map. Monitoring results of PX oxidation reaction process in-dicate that the LTSA–SOM can wel detect and visualize the fault type.

Structural insight into molecular mechanism of poly(ethylene terephthalate) degradation.

Science.gov (United States)

Joo, Seongjoon; Cho, In Jin; Seo, Hogyun; Son, Hyeoncheol Francis; Sagong, Hye-Young; Shin, Tae Joo; Choi, So Young; Lee, Sang Yup; Kim, Kyung-Jin

2018-01-26

Plastics, including poly(ethylene terephthalate) (PET), possess many desirable characteristics and thus are widely used in daily life. However, non-biodegradability, once thought to be an advantage offered by plastics, is causing major environmental problem. Recently, a PET-degrading bacterium, Ideonella sakaiensis, was identified and suggested for possible use in degradation and/or recycling of PET. However, the molecular mechanism of PET degradation is not known. Here we report the crystal structure of I. sakaiensis PETase (IsPETase) at 1.5 Å resolution. IsPETase has a Ser-His-Asp catalytic triad at its active site and contains an optimal substrate binding site to accommodate four monohydroxyethyl terephthalate (MHET) moieties of PET. Based on structural and site-directed mutagenesis experiments, the detailed process of PET degradation into MHET, terephthalic acid, and ethylene glycol is suggested. Moreover, other PETase candidates potentially having high PET-degrading activities are suggested based on phylogenetic tree analysis of 69 PETase-like proteins.

Modification of N-Methyl-N-Nitrosourea initiated bladder carcinogenesis in Wistar rats by terephthalic acid

International Nuclear Information System (INIS)

Cui Lunbiao; Shi Yuan; Dai Guidong; Pan Hongxin; Chen Jianfeng; Song Ling; Wang Shouling; Chang, Hebron C.; Sheng Hongbing; Wang Xinru

2006-01-01

The effect of terephthalic acid (TPA) on urinary bladder carcinogenesis was examined. Male Wistar rats were initiated by injection of N-Methyl-N-Nitrosourea (MNU) (20 mg/kg b.w. ip) twice a week for 4 weeks, then given basal diet containing 5% TPA, 5% TPA plus 4% Sodium bicarbonate (NaHCO 3 ) or 1% TPA for the next 22 weeks, and then euthanized. 5% TPA treatment induced a high incidence of urinary bladder calculi and a large amount of precipitate. Though 5% TPA plus 4% Sodium bicarbonate (NaHCO 3 ) and 1% TPA treatment did not induce urinary bladder calculi formation, they resulted in a moderate increase in urinary precipitate. Histological examination of urinary bladder revealed that MNU-5% TPA treatment resulted in a higher incidence of simple hyperplasia, papillary or nodular hyperplasia (PN hyperplasia), papilloma and cancer than MNU control. MNU-5% TPA plus 4% Sodium bicarbonate (NaHCO 3 ) and 1% TPA treatment increased slightly the incidence of simple hyperplasia and PN hyperplasia (not statistically significant). The major elements of the precipitate are phosphorus, potassium, sulfur, chloride, calcium and TPA. The present study indicated that the calculi induced by TPA had a strong promoting activity on urinary bladder carcinogenesis and the precipitate containing calcium terephthalate (CaTPA) may also have weak promoting activity on urinary bladder carcinogenesis

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.

Speciation of antimony in polyethylene terephthalate bottles

International Nuclear Information System (INIS)

Martin, R.R.; Ablett, J.; Shotyk, W.S.; Naftel, S.; Northrup, P.

2010-01-01

Antimony contamination has been reported in drinking water from polyethylene terephthalate (PET) bottles. Micro-X-ray fluorescence (XRF) analysis has been used to identify the distribution and chemical form of residual antimony used as a catalyst in the manufacture of PET bottles. The results are consistent with clusters of Sb(III) having dimensions of the order of tens of micrometers, clearly showing the ability of synchrotron radiation analyses to both map elemental distribution and determine oxidation state.

Influence of the addition of bentonite clay in poli (butylene adipate co-terephthalic) / poly(lactic acid) membranes

International Nuclear Information System (INIS)

Morais, D.D.S.; Medeiros, K.M.; Araujo, E.M.; Melo, T.J.A.; Barbosa, R.

2014-01-01

The processes of membrane separation have been used in many different sectors of industrial activity, ranging from the chemical industry, food, pharmaceutical, medical and biotech. In this paper, a bentonite clay was added by melt intercalation in a poly(butylene adipate-co-terephthalic acid)/poly(lactic acid) blend at levels 1 and 3 wt% of clay. After that, membranes were produced by solvent evaporation technique. From the XRD results, it was verified the possible formation of exfoliated/partially exfoliated structures in the membranes. By DSC, it was observed that the addition of clay did not promote alterations in glass transition temperature and crystalline melting of the PBAT/PLA matrix. The morphology of the membranes were observed by SEM and it was verified the clay formation of porous membranes. (author)

Physical and dielectric properties of irradiated polypropylene and poly(ethylene terephthalate)

International Nuclear Information System (INIS)

Kita, H.; Okamoto, K.

1986-01-01

The effect of high-energy electron irradiation in air and in nitrogen on the physical and dielectric properties of polypropylene and poly(ethylene terephthalate) has been studied by measurements of electric strength, dielectric constant, dissipation factor, tensile strength, gel fraction and molecular weight distribution. Electric strength of polypropylene was improved by irradiation, while dielectric properties of poly(ethylene terephthalate) were virtually unaffected by irradiation of 1.0-20 Mrad. Possible mechanisms for increasing electric strength are discussed from the point of view of degradation and oxidation taking place simultaneously with crosslinking of polypropylene. The maximum dose level to improve the electric strength of polypropylene is determined to be about 5 Mrad. (author)

On the Diels-Alder approach to solely biomass-derived polyethylene terephthalate (PET): conversion of 2,5-dimethylfuran and acrolein into p-xylene.

Science.gov (United States)

Shiramizu, Mika; Toste, F Dean

2011-10-24

Polyethylene terephthalate (PET) is a polymeric material with high global demand. Conventionally, PET is produced from fossil-fuel-based materials. Herein, we explored the feasibility of a sustainable method for PET production by using solely bio-renewable resources. Specifically, 2,5-dimethylfuran (derived from lignocellulosic biomass through 5-(hydroxymethyl)furfural) and acrolein (produced from glycerol, a side product of biodiesel production) were converted into the key intermediate p-xylene (a precursor of terephthalic acid). This synthesis consists of a sequential Diels-Alder reaction, oxidation, dehydration, and decarboxylation. In particular, the pivotal first step, the Diels-Alder reaction, was studied in detail to provide useful kinetic and thermodynamic data. Although it was found that this reaction requires low temperature to proceed efficiently, which presents a limitation on economic feasibility on an industrial scale, the concept was realized and bio-derived p-xylene was obtained in 34% overall yield over four steps. Copyright © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

The oxidation of PET track-etched membranes by hydrogen peroxide as an effective method to increase efficiency of UV-induced graft polymerization

OpenAIRE

Il'ya Korolkov; Abzal Taltenov; Anastassiya Mashentseva; Olgun Guven

2015-01-01

In this article, we report on functionalization of track-etched membrane based on poly(ethylene terephthalate) (PET TeMs) oxidized by advanced oxidation systems and by grafting of acrylic acid using photochemical initiation technique for the purpose of increasing functionality thus expanding its practical application. Among advanced oxidation processes (H2O2/UV) system had been chosen to introduce maximum concentration of carboxylic acid groups. Benzophenone (BP) photo-initiator was first im...

Trials of separation of the rare-earth elements on the way of fractional precipitation of terephthalates

Energy Technology Data Exchange (ETDEWEB)

Brzyska, W. (Uniwersytet Marii Curie-Sklodowskiej, Lublin (Poland))

1980-01-01

A possibility of the rare-earth elements separation on the way of fractional precipitation of terephthalates in the presence of a complexing agent was studied. Selecting an appropriate quantity of the complexing agent, it is possible to obtain fractions differing in their composition. In the first fractions the light lanthanides accumulate, whereas in the last one accumulate Y and heavy lanthanides. The advantage of this method is that the terephthalic acid can be regenerated practically in 100%.

Simultaneous recovery of benzene-rich oil and metals by steam pyrolysis of metal-poly(ethylene terephthalate) composite waste.

Science.gov (United States)

Kumagai, Shogo; Grause, Guido; Kameda, Tomohito; Yoshioka, Toshiaki

2014-03-18

The possibility of simultaneous recovery of benzene and metals from the hydrolysis of poly(ethylene terephthalate) (PET)-based materials such as X-ray films, magnetic tape, and prepaid cards under a steam atmosphere at a temperature of 450 °C was evaluated. The hydrolysis resulted in metal-containing carbonaceous residue and volatile terephthalic acid (TPA). The effects of metals and additives on the recovery process were also investigated. All metals were quantitatively recovered, and silver, maghemite (γ-Fe2O3), and anatase (TiO2) were recovered without any changes in their crystal structures or compositions. In a second step, TPA was decarboxylized in the presence of calcium oxide (CaO) at 700 °C, producing benzene with an average yield of 34% and purity of 76%. Maghemite (γ-Fe2O3) incorporated in magnetic tape and prepaid cards could decarboxylate TPA. Aluminum present in the prepaid cards produced hydrogen by the reaction with steam. However, the presence of metals had no adverse influence on the recovery of benzene-rich oil in the presence of CaO. Therefore, this method can be applied to PET-based materials containing inorganic substances, which cannot be recycled effectively otherwise.

Aspirin increases mitochondrial fatty acid oxidation

International Nuclear Information System (INIS)

Uppala, Radha; Dudiak, Brianne; Beck, Megan E.; Bharathi, Sivakama S.; Zhang, Yuxun; Stolz, Donna B.; Goetzman, Eric S.

2017-01-01

The metabolic effects of salicylates are poorly understood. This study investigated the effects of aspirin on fatty acid oxidation. Aspirin increased mitochondrial long-chain fatty acid oxidation, but inhibited peroxisomal fatty acid oxidation, in two different cell lines. Aspirin increased mitochondrial protein acetylation and was found to be a stronger acetylating agent in vitro than acetyl-CoA. However, aspirin-induced acetylation did not alter the activity of fatty acid oxidation proteins, and knocking out the mitochondrial deacetylase SIRT3 did not affect the induction of long-chain fatty acid oxidation by aspirin. Aspirin did not change oxidation of medium-chain fatty acids, which can freely traverse the mitochondrial membrane. Together, these data indicate that aspirin does not directly alter mitochondrial matrix fatty acid oxidation enzymes, but most likely exerts its effects at the level of long-chain fatty acid transport into mitochondria. The drive on mitochondrial fatty acid oxidation may be a compensatory response to altered mitochondrial morphology and inhibited electron transport chain function, both of which were observed after 24 h incubation of cells with aspirin. These studies provide insight into the pathophysiology of Reye Syndrome, which is known to be triggered by aspirin ingestion in patients with fatty acid oxidation disorders. - Highlights: • Aspirin increases mitochondrial—but inhibits peroxisomal—fatty acid oxidation. • Aspirin acetylates mitochondrial proteins including fatty acid oxidation enzymes. • SIRT3 does not influence the effect of aspirin on fatty acid oxidation. • Increased fatty acid oxidation is likely due to altered mitochondrial morphology and respiration.

Low-cost flexible supercapacitors based on laser reduced graphene oxide supported on polyethylene terephthalate substrate

Science.gov (United States)

Ghoniem, Engy; Mori, Shinsuke; Abdel-Moniem, Ahmed

2016-08-01

A controlled high powered CO2 laser system is used to reduce and pattern graphene oxide (GO) film supported onto a flexible polyethylene terephthalate (PET) substrate. The laser reduced graphene oxide (rGO) film is characterized and evaluated electrochemically in the absence and presence of an overlying anodicaly deposited thin film of pseuodcapactive MnO2 as electrodes for supercapacitor applications using aqueous electrolyte. The laser treatment of the GO film leads to an overlapped structure of defective multi-layer rGO sheets with an electrical conductivity of 273 S m-1. The rGO and MnO2/rGO electrodes exhibit specific capacitance in the range of 82-107 and 172-368 Fg-1 at applied current range of 0.1-1.0 mA cm-2 and retain 98 and 95% of their initial capacitances after 2000 cycles at a current density of 1.0 mA cm-2, respectively. Also, the rGO is assigned as an electrode material for flexible conventionally stacked and interdigitated in-plane supercapacitor structures using gel electrolyte. Three electrode architectures of 2, 4, and 6 sub-electrodes are studied for the interdigital in-plane design. The device with interdigital 6 sub-electrodes architecture I-PS(6) delivers power density of 537.1 Wcm-3 and an energy density of 0.45 mWh cm-3.

Interfacial characteristics of polyethylene terephthalate-based piezoelectric multi-layer films

International Nuclear Information System (INIS)

Liu, Z.H.; Pan, C.T.; Chen, Y.C.; Liang, P.H.

2013-01-01

The study examines the deformation between interfaces and the adhesion mechanism of multi-layer flexible electronic composites. Indium tin oxide (ITO), aluminum (Al), and zinc oxide (ZnO) were deposited on a polyethylene terephthalate (PET) substrate using radio frequency magnetron sputtering at room temperature to form flexible structures (e.g., ITO/PET, Al/PET, ZnO/ITO/PET, and ZnO/Al/PET) for piezoelectric transducers. ITO and Al films are used as the conductive layers. A ZnO thin film shows a high (002) c-axis preferred orientation at 2θ = 34.45° and excellent piezoelectric properties. Nanoscratching and nano-indention testing were conducted to analyze the adhesion following periodic mechanical stress. Additionally, two Berkovich and conical probes with a curvature radius of 40 nm and 10 μm are examined for the scratching test. A 4-point probe is used to measure the conductive properties. The plastic deformation between the ductile Al film and PET substrate is observed using scanning electron microscopy to examine the chip formation on the ITO/PET. Delamination between the ZnO and Al/PET substrate was not observed. The result suggests that ZnO film has excellent adhesion with Al/PET compared to ITO/PET. - Highlights: ► Interfaces and adhesion mechanism of multi-layer flexible electronic composites ► Polyethylene terephthalate (PET) based flexible structures ► Nano-scratching and nano-indention tests were used to analyze adhesion. ► Using two various probes of Berkovich and conical ► Piezoelectric zinc oxide film has excellent adhesion with aluminum/PET

New Titanium-Based Catalysts for the Synthesis of Poly(ethylene terephthalate)

International Nuclear Information System (INIS)

Yang, Youngkeun; Yoon, Seungwoong; Hwang, Yongtaek; Song, Bogeun

2012-01-01

Poly(ethylene terephthalate) (PET) is a polymer with relatively low cost and high performance, which is widely used in various applications such as bottles, textile fibers, films and engineering plastics for automobiles and electric industries. Commercial catalysts used for synthesis of PET are in general antimony (Sb) compounds. Antimony(III) oxide, antimony(III) acetate and antimony(III) glycolate are used as a catalyst in 95% of PET manufacturing industries worldwide. The few organoantimony compounds that have been identified in environmental and biological samples are all in the form of methylated Sb-species. The Sb trace element is extremely toxic to mammals, and interferes with embryonic and fetal development, also, carcinogenic to humans. In addition to being found in drinking water, food packaging and soft-drink bottles. According to the World Health Organization (WHO), Sb species concentration lower than 20 ppb are acceptable for drinking water. According to a recent study, in 14 brands of bottled water from Canada, Sb concentrations increased on average 19% during 6 months storage at room temperature, but 48 brands of water from 11 European countries increased on average 90% under identical conditions. Therefore, a very important challenge for polyester catalysis is to come-up with a new Sb-free catalysts with low environmental impact. Intensive efforts have been made to find other stable and more environmental friendly non-antimony catalysts, such as those based on titanium. Titanium-based catalysts have been known for many years and actually are used for polybutylene terephthalate (PBT) and polypropylene terephthalate (PPT) production, however, polycondensation (PC) of PET manufacture is not well studied in literature. To date, only few esterification processes have been applied for the synthesis of PET by titanium catalysts. Herein, we report an efficient synthesis characterization and polymerization of PET for a series of new nontoxic organotitanium

The effect of oxygen ion beam bombardment on the properties of tin indium oxide/polyethylene terephthalate complex

International Nuclear Information System (INIS)

Li, Li; Liu, Honglin; Zou, Lin; Ding, Wanyu; Ju, Dongying; Chai, Weiping

2013-01-01

The tin indium oxide (ITO) films were deposited onto the polyethylene terephthalate (PET) surface that has been bombarded by an O ion beam. The variation of the O bombardment time resulted in the production of ITO/PET complex with different properties. Characterization by four-point probe measurement after the bending fatigue test showed that the adhesion property of the ITO/PET complex could be improved by the increase of O bombardment time while little change of electrical resistivity was observed. Scanning electron microscopy results showed that after the bending fatigue test, the nano scale seams and micro scale trenches appeared at the surface of the ITO/PET complex. The former was only the cracks of ITO film, which has little influence on the continuity and electrical resistivity of ITO film. On the contrary, the micro scale trenches were caused by the peeling off of ITO chips at the cracks, which mainly influenced the continuity and electrical resistivity of ITO film. With the increase of O bombardment time, the number and length of the micro scale trenches decreased. X-ray photoelectron spectrometry characterization showed that with the increase of O bombardment time, parts of the methylene C bonds were transformed into C=O bonds, which could be broken to form C-O-In(Sn) bonds at the initial stage of ITO film growth. By these C-O-In(Sn) crosslink bonds, the ITO film could adhere well onto the PET and the ITO/PET complex display better anti-bending fatigue property. Finally, in the context of the application of the ITO/PET complex as a flexible electrode substrate, the present work reveals a simple way to crosslink them, as well as the physicochemical mechanism happening at the interface of complex. - Highlights: • Polyethylene terephthalate (PET) surface was bombarded by N ions. • Tin indium oxide (ITO) film was deposited on bombarded PET surface. • By bombardment, methylene C bond on PET surface was broken and replaced by C=O bond. • C=O bond was

The effect of oxygen ion beam bombardment on the properties of tin indium oxide/polyethylene terephthalate complex

Energy Technology Data Exchange (ETDEWEB)

Li, Li; Liu, Honglin; Zou, Lin [School of Materials Science and Engineering, Dalian Jiaotong University, Dalian 116028 (China); Ding, Wanyu, E-mail: dwysd_2000@163.com [School of Materials Science and Engineering, Dalian Jiaotong University, Dalian 116028 (China); Key Laboratory of Materials Modification by Laser, Ion and Electron Beams (Dalian University of Technology), Ministry of Education, Dalian 116028 (China); Ju, Dongying [Department of Material Science and Engineering, Saitama Institute of Technology, Fukaya 369-0293 (Japan); Chai, Weiping [School of Materials Science and Engineering, Dalian Jiaotong University, Dalian 116028 (China)

2013-10-31

The tin indium oxide (ITO) films were deposited onto the polyethylene terephthalate (PET) surface that has been bombarded by an O ion beam. The variation of the O bombardment time resulted in the production of ITO/PET complex with different properties. Characterization by four-point probe measurement after the bending fatigue test showed that the adhesion property of the ITO/PET complex could be improved by the increase of O bombardment time while little change of electrical resistivity was observed. Scanning electron microscopy results showed that after the bending fatigue test, the nano scale seams and micro scale trenches appeared at the surface of the ITO/PET complex. The former was only the cracks of ITO film, which has little influence on the continuity and electrical resistivity of ITO film. On the contrary, the micro scale trenches were caused by the peeling off of ITO chips at the cracks, which mainly influenced the continuity and electrical resistivity of ITO film. With the increase of O bombardment time, the number and length of the micro scale trenches decreased. X-ray photoelectron spectrometry characterization showed that with the increase of O bombardment time, parts of the methylene C bonds were transformed into C=O bonds, which could be broken to form C-O-In(Sn) bonds at the initial stage of ITO film growth. By these C-O-In(Sn) crosslink bonds, the ITO film could adhere well onto the PET and the ITO/PET complex display better anti-bending fatigue property. Finally, in the context of the application of the ITO/PET complex as a flexible electrode substrate, the present work reveals a simple way to crosslink them, as well as the physicochemical mechanism happening at the interface of complex. - Highlights: • Polyethylene terephthalate (PET) surface was bombarded by N ions. • Tin indium oxide (ITO) film was deposited on bombarded PET surface. • By bombardment, methylene C bond on PET surface was broken and replaced by C=O bond. • C=O bond was

Electrochemical pulsed deposition of platinum nanoparticles on indium tin oxide/polyethylene terephthalate as a flexible counter electrode for dye-sensitized solar cells

International Nuclear Information System (INIS)

Wei, Yu-Hsuan; Chen, Chih-Sheng; Ma, Chen-Chi M.; Tsai, Chuen-Horng; Hsieh, Chien-Kuo

2014-01-01

In this study, a pulsed-mode electrochemical deposition (Pulse-ECD) technique was employed to deposit platinum nanoparticles (PtNPs) on the indium tin oxide/polyethylene terephthalate (ITO/PET) substrate as a flexible counter electrode for dye-sensitized solar cells (DSSCs). The characteristic properties of the Pulse-ECD PtNPs were prepared and compared to the traditional (electron beam) Pt film. The surface morphologies of the PtNPs were examined by field emission scanning electron microscopy (FE-SEM) and the atomic force microscope (AFM). The FE-SEM results showed that our PtNPs were deposited uniformly on the ITO/PET flexible substrates via the Pulse-ECD technique. The AFM results indicated that the surface roughness of the pulsed PtNPs influenced the power conversion efficiency (PCE) of DSSCs, due to the high specific surface area of PtNPs which enhanced the catalytic activities for the reduction (I 3 − to I − ) of redox electrolyte. In combination with a N719 dye-sensitized TiO 2 working electrode and an iodine-based electrolyte, the DSSCs with the PtNPs flexible counter electrode showed a PCE of 4.3% under the illumination of AM 1.5 (100 mW cm −2 ). The results demonstrated that the Pulse-ECD PtNPs are good candidate for flexible DSSCs. - Highlights: • We used indium tin oxide/polyethylene terephthalate as a flexible substrate. • We utilized pulse electrochemical deposition to deposit platinum nanoparticles. • We synthesized a flexible counter electrode for dye-sensitized solar cell (DSSC). • The power conversion efficiency of DSSC was measured to be 4.3%

Oxidative Decarboxylation of Levulinic Acid by Cupric Oxides

Directory of Open Access Journals (Sweden)

Lu Lin

2010-11-01

Full Text Available In this paper, cupric oxides was found to effectively oxidize levulinic acid (LA and lead to the decarboxylation of levulinic acid to 2-butanone. The effects of cupric oxide dosage, reaction time and initial pH value were investigated in batch experiments and a plausible mechanism was proposed. The results showed that LA decarboxylation over cupric oxides at around 300 °C under acidic conditions produced the highest yield of butanone (67.5%. In order to elucidate the catalytic activity of cupric oxides, XRD, AFM, XPS and H2-TPR techniques was applied to examine their molecular surfaces and their effects on the reaction process.

Preparation and characterization of polymer blends based on recycled PET and polyester derived by terephthalic acid

International Nuclear Information System (INIS)

Ohara, L.; Miranda, C.S.; Fiuza, R.P.; Luporini, S.; Carvalho, R.F.; Jose, N.M.

2010-01-01

Environmentally friendly materials, made from industrial waste, are being increasingly used as a solution to the growing amount of waste generated by society, but also as a cheaper alternative to replace conventional materials for use in construction. In this work were investigated the properties of polymer blends based on recycled PET and a polyester derived from terephthalic acid and glycerin, a co-product of biodiesel. The samples were characterized by XRD, TGA, DSC, FTIR and SEM. The polyester synthesized showed a degradation event near 300 deg C. The blends with higher ratio of PET showed thermal behavior similar to pure PET. The X-ray diffraction showed that the polymer blends are semicrystalline materials. The micrographs presents the presence of a smooth surface, indicating the possibility of miscibility between the arrays. Therefore, the blending makes possible the fabrication of low-cost materials with applications in several areas. (author)

Production of Valuables Organic Acids from Organic Wastes with Hydrothermal Treatment Process

Directory of Open Access Journals (Sweden)

Muhammad Faisal

2009-06-01

Full Text Available This article reports production of valuables organic acids from the hydrothermal treatment of representative organic wastes and compounds (i. e. domestic sludge, proteinaceous, cellulosic and plastic wastes with or without oxidant (H2O2. Organic acids such as acetic, formic, propionic, succinic and lactic acids were obtained in significant amounts. At 623 K (16.5 MPa, acetic acid of about 26 mg/g-dry waste fish entrails was obtained. This increased to 42 mg/g dry waste fish entrails in the presence of H2O2. Experiments on glucose to represent cellulosic wastes were also carried out, getting acetic acid of about 29 mg/g-glucose. The study was extended to terephthalic acid and glyceraldehyde, reaction intermediates of hydrothermal treatment of PET plastic wastes and glucose, respectively. Studies on temperature dependence of formation of organic acids showed thermal stability of acetic acid, whereas, formic acid decomposed readily under hydrothermal conditions. In general, results demonstrated that the presence of oxidants favored formation of organic acids with acetic acid being the major product. Keywords: hydrothermal treatment, organic acids, organic wastes, oxidant, supercritical water oxidation

Treatment of Fatty Acid Oxidation Disorders

Science.gov (United States)

... Treatment of fatty acid oxidation disorders Treatment of fatty acid oxidation disorders E-mail to a friend Please ... this page It's been added to your dashboard . Fatty acid oxidation disorders are rare health conditions that affect ...

Biohydrogen production from purified terephthalic acid (PTA) processing wastewater by anaerobic fermentation using mixed microbial communities

Energy Technology Data Exchange (ETDEWEB)

Zhu, Ge-Fu; Wu, Peng; Wei, Qun-Shan; Lin, Jian-yi; Liu, Hai-Ning [Key Lab of Urban Environment and Health, Institute of Urban Environment, Chinese Academy of Sciences, Xiamen 361021 (China); Gao, Yan-Li [China University of Geosciences, Wuhan 430074 (China)

2010-08-15

Purified terephthalic acid (PTA) processing wastewater was evaluated as a fermentable substrate for hydrogen (H{sub 2}) production with simultaneous wastewater treatment by dark-fermentation process in a continuous stirred-tank reactor (CSTR) with selectively enriched acidogenic mixed consortia under continuous flow condition in this paper. The inoculated sludge used in the reactor was excess sludge taken from a second settling tank in a local wastewater treatment plant. Under the conditions of the inoculants not less than 6.3 gVSS/L, the organic loading rate (OLR) of 16 kgCOD/m{sup 3} d, hydraulic retention time (HRT) of 6 h and temperature of (35 {+-} 1) C, when the pH value, alkalinity and oxidation-reduction potential (ORP) of the effluent ranged from 4.2 to 4.4, 280 to 350 mg CaCO{sub 3}/L, and -220 to -250 mV respectively, soluble metabolites were predominated by acetate and ethanol, with smaller quantities of propionate, butyrate and valerate. Stable ethanol-type fermentation was formed with the sum of ethanol and acetate concentration ratio of 70.31% to the total liquid products after 25 days operation. The H{sub 2} volume content was estimated to be 48-53% of the total biogas and the biogas was free of methane throughout the study. The average biomass concentration was estimated to be 10.82 gVSS/L, which favored H{sub 2} production efficiently. The rate of chemical oxygen demand (COD) removal reached at about 45% and a specific H{sub 2} production rate achieved 0.073 L/gMLVSS d in the study. This CSTR system showed a promising high-efficient bioprocess for H{sub 2} production from high-strength chemical wastewater. (author)

The influence of manganese–cobalt oxide/graphene on reducing fire hazards of poly(butylene terephthalate)

Energy Technology Data Exchange (ETDEWEB)

Wang, Dong; Zhang, Qiangjun; Zhou, Keqing; Yang, Wei [State Key Laboratory of Fire Science, University of Science and Technology of China, 96 Jinzhai Road, Hefei, Anhui 230026 (China); Hu, Yuan, E-mail: yuanhu@ustc.edu.cn [State Key Laboratory of Fire Science, University of Science and Technology of China, 96 Jinzhai Road, Hefei, Anhui 230026 (China); USTC-CityU Joint Advanced Research Centre, Suzhou Key Laboratory of Urban Public Safety, Suzhou Institute for Advanced Study, University of Science and Technology of China, 166 Ren’ai Road, Suzhou, Jiangsu 215123 (China); Gong, Xinglong, E-mail: gongxl@ustc.edu.cn [State Key Laboratory of Fire Science, University of Science and Technology of China, 96 Jinzhai Road, Hefei, Anhui 230026 (China); CAS Key Laboratory of Mechanical Behaviour and Design of Materials, Department of Modern Mechanics, University of Science and Technology of China, Hefei, Anhui 230026 (China)

2014-08-15

Highlights: • MnCo{sub 2}O{sub 4}–GNS hybrids are synthesized by a two-stage liquid phase method. • MnCo{sub 2}O{sub 4}–GNS/PBT composites were prepared via a masterbatch-melt blending method. • Fire hazards are monitored and evaluated by cone calorimeter and TG-IR. • MnCo{sub 2}O{sub 4}–GNS hybrids decrease thermal hazards and smoke hazards of PBT composites. • MnCo{sub 2}O{sub 4}–GNS hybrids perform better catalytic oxidation of CO and organic volatile. - Abstract: By means of direct nucleation and growth on the surface of graphene and element doping of cobalt oxide (Co{sub 3}O{sub 4}) nano-particles, manganese–cobalt oxide/graphene hybrids (MnCo{sub 2}O{sub 4}–GNS) were synthesized to reduce fire hazards of poly(butylene terephthalate) (PBT). The structure, elemental composition and morphology of the obtained hybrids were surveyed by X-ray diffraction, X-ray photoelectron spectrometer and transmission electron microscopy, respectively. Thermogravimetric analysis was applied to simulate and study the influence of MnCo{sub 2}O{sub 4}–GNS hybrids on thermal degradation of PBT during combustion. The fire hazards of PBT and its composites were assessed by the cone calorimeter. The cone test results had showed that peak HRR and SPR values of MnCo{sub 2}O{sub 4}–GNS/PBT composites were lower than that of pure PBT and Co{sub 3}O{sub 4}–GNS/PBT composites. Furthermore, the incorporation of MnCo{sub 2}O{sub 4}–GNS hybrids gave rise to apparent decrease of pyrolysis products containing aromatic compounds, carbonyl compounds, carbon monoxide and carbon dioxide, attributed to combined impact of physical barrier for graphene and cat O{sub 4} for organic volatiles and carbon monoxide.

The influence of manganese–cobalt oxide/graphene on reducing fire hazards of poly(butylene terephthalate)

International Nuclear Information System (INIS)

Wang, Dong; Zhang, Qiangjun; Zhou, Keqing; Yang, Wei; Hu, Yuan; Gong, Xinglong

2014-01-01

Highlights: • MnCo 2 O 4 –GNS hybrids are synthesized by a two-stage liquid phase method. • MnCo 2 O 4 –GNS/PBT composites were prepared via a masterbatch-melt blending method. • Fire hazards are monitored and evaluated by cone calorimeter and TG-IR. • MnCo 2 O 4 –GNS hybrids decrease thermal hazards and smoke hazards of PBT composites. • MnCo 2 O 4 –GNS hybrids perform better catalytic oxidation of CO and organic volatile. - Abstract: By means of direct nucleation and growth on the surface of graphene and element doping of cobalt oxide (Co 3 O 4 ) nano-particles, manganese–cobalt oxide/graphene hybrids (MnCo 2 O 4 –GNS) were synthesized to reduce fire hazards of poly(butylene terephthalate) (PBT). The structure, elemental composition and morphology of the obtained hybrids were surveyed by X-ray diffraction, X-ray photoelectron spectrometer and transmission electron microscopy, respectively. Thermogravimetric analysis was applied to simulate and study the influence of MnCo 2 O 4 –GNS hybrids on thermal degradation of PBT during combustion. The fire hazards of PBT and its composites were assessed by the cone calorimeter. The cone test results had showed that peak HRR and SPR values of MnCo 2 O 4 –GNS/PBT composites were lower than that of pure PBT and Co 3 O 4 –GNS/PBT composites. Furthermore, the incorporation of MnCo 2 O 4 –GNS hybrids gave rise to apparent decrease of pyrolysis products containing aromatic compounds, carbonyl compounds, carbon monoxide and carbon dioxide, attributed to combined impact of physical barrier for graphene and cat O 4 for organic volatiles and carbon monoxide

The solubilities of benzene polycarboxylic acids in water

International Nuclear Information System (INIS)

Apelblat, Alexander; Manzurola, Emanuel; Abo Balal, Nazmia

2006-01-01

The solubilities in water of all benzene polycarboxylic acids are discussed, using data determined in this work (benzoic, terephthalic, trimellitic, trimesic, and pyromellitic acids) and available from the literature (benzoic, phthalic, isophthalic, terephthalic, hemimellitic, trimelitic, trimesic, mellophanic, prehnitic, pyromellitic, benzene-pentacarboxylic and mellitic acids). The apparent molar enthalpies of solution at the saturation point for these benzene polycarboxylic acids were determined from the temperature dependence of the solubilities

Morphology, melting behavior, and non-isothermal crystallization of poly(butylene terephthalate)/poly(ethylene-co-methacrylic acid) blends

International Nuclear Information System (INIS)

Huang, J.-W.; Wen, Y.-L.; Kang, C.-C.; Yeh, M.-Y.; Wen, S.-B.

2007-01-01

The morphology, melting behavior, and non-isothermal crystallization of poly(butylene terephthalate) (PBT) and poly(ethylene-co-methacrylic acid) (PEMA) blends were studied with scanning electron microscopy, X-ray diffraction and differential scanning calorimetry (DSC). PEMA forms immiscible, yet compatible, blends with PBT. Subsequent DSC scans on melt-crystallized samples exhibited two melting endotherms (T mI and T mII ). The presence of PEMA would facilitate the recrystallization during heating scan and retard PBT molecular chains to form a perfect crystal in cooling crystallization. The dispersion phases of molten PEMA acts as nucleating agents to enhance the crystallization rate of PBT. The solidified PBT could act as nucleating agents to enhance the crystallization of PEMA, but also retard the molecular mobility to reduce crystallization rate. The U* and K g of Hoffman-Lauritzen theory were also determined by Vyazovkin's methods to support the interpretation

Processing and characterization of recycled poly(ethylene terephthalate) blends with chain extenders, thermoplastic elastomer, and/or poly(butylene adipate-co-terephthalate)

Science.gov (United States)

Yottha Srithep; Alireza Javadi; Srikanth Pilla; Lih-Sheng Turng; Shaoqin Gong; Craig Clemons; Jun Peng

2011-01-01

Poly(ethylene terephthalate) (PET) resin is one of the most widely used thermoplastics, especially in packaging. Because thermal and hydrolytic degradations, recycled PET (RPET) exhibits poor mechanical properties and lacks moldability. The effects of adding elastomeric modifiers, chain extenders (CE), and poly(butylenes adipate-co-terephthalate), PBAT, as a toughener...

Control of bovine hepatic fatty acid oxidation

International Nuclear Information System (INIS)

Jesse, B.W.; Emery, R.S.; Thomas, J.W.

1986-01-01

Fatty acid oxidation by bovine liver slices and mitochondria was examined to determine potential regulatory sites of fatty acid oxidation. Conversion of 1-[ 14 C]palmitate to 14 CO 2 and total [ 14 C]acid-soluble metabolites was used to measure fatty acid oxidation. Oxidation of palmitate (1 mM) was linear in both liver slice weight and incubation time. Carnitine stimulated palmitate oxidation; 2 mM dl-carnitine produced maximal stimulation of palmitate oxidation to both CO 2 and acid-soluble metabolites. Propionate (10 mM) inhibited palmitate oxidation by bovine liver slices. Propionate (.5 to 10 mM) had no effect on palmitate oxidation by mitochondria, but malonyl Coenzyme A, the first committed intermediate of fatty acid synthesis, inhibited mitochondrial palmitate oxidation (inhibition constant = .3 μM). Liver mitochonndrial carnitine palmitoyltransferase exhibited Michaelis constants for palmitoyl Coenzyme A and l-carnitine of 11.5 μM and .59 mM, respectively. Long-chain fatty acid oxidation in bovine liver is regulated by mechanisms similar to those in rats but adapted to the unique digestive physiology of the bovine

Nickel Inhibits Mitochondrial Fatty Acid Oxidation

Science.gov (United States)

Uppala, Radha; McKinney, Richard W.; Brant, Kelly A.; Fabisiak, James P.; Goetzman, Eric S.

2015-01-01

Nickel exposure is associated with changes in cellular energy metabolism which may contribute to its carcinogenic properties. Here, we demonstrate that nickel strongly represses mitochondrial fatty acid oxidation—the pathway by which fatty acids are catabolized for energy—in both primary human lung fibroblasts and mouse embryonic fibroblasts. At the concentrations used, nickel suppresses fatty acid oxidation without globally suppressing mitochondrial function as evidenced by increased glucose oxidation to CO2. Pre-treatment with L-carnitine, previously shown to prevent nickel-induced mitochondrial dysfunction in neuroblastoma cells, did not prevent the inhibition of fatty acid oxidation. The effect of nickel on fatty acid oxidation occurred only with prolonged exposure (>5 hr), suggesting that direct inhibition of the active sites of metabolic enzymes is not the mechanism of action. Nickel is a known hypoxia-mimetic that activates hypoxia inducible factor-1α (HIF1α). Nickel-induced inhibition of fatty acid oxidation was blunted in HIF1α knockout fibroblasts, implicating HIF1α as one contributor to the mechanism. Additionally, nickel down-regulated the protein levels of the key fatty acid oxidation enzyme very long-chain acyl-CoA dehydrogenase (VLCAD) in a dose-dependent fashion. In conclusion, inhibition of fatty acid oxidation by nickel, concurrent with increased glucose metabolism, represents a form of metabolic reprogramming that may contribute to nickel-induced carcinogenesis. PMID:26051273

Catalyzed oxidation reactions. IV. Picolinic acid catalysis of chromic acid oxidations

International Nuclear Information System (INIS)

Rocek, J.; Peng, T.Y.

1977-01-01

Picolinic acid and several closely related acids are effective catalysts in the chromic acid oxidation of primary and secondary alcohols; the oxidation of other substrates is accelerated only moderately. The reaction is first order in chromium-(VI), alcohol, and picolinic acid; it is second order in hydrogen ions at low acidity and approaches acidity independence at high perchloric acid concentrations. A primary deuterium kinetic isotope effect is observed at high but not at low acidities. At low acidity the reaction has a considerably lower activation energy and more negative activation entropy than at higher acidities. The reactive intermediate in the proposed mechanism is a negatively charged termolecular complex formed from chromic acid, picolinic acid, and alcohol. The rate-limiting step of the reaction changes with the acidity of the solution. At higher acidities the intermediate termolecular complex is formed reversibly and the overall reaction rate is determined by the rate of its decomposition into reaction products; at low acidities the formation of the complex is irreversible and hence rate limiting. Picolinic acids with a substituent in the 6 position show a greatly reduced catalytic activity. This observation is interpreted as suggesting a square pyramidal or octahedral structure for the reactive chromium (VI) intermediate. The temperature dependence of the deuterium isotope effect has been determined and the significance of the observed large values for E/sub a//sup D/ - E/sub a//sup H/ and A/sup D//A/sup H/ is discussed

76 FR 54791 - Polyethylene Terephthalate (PET) Film From Korea

Science.gov (United States)

2011-09-02

... Terephthalate (PET) Film From Korea Determination On the basis of the record \\1\\ developed in the subject five... order on polyethylene terephthalate (PET) film from Korea would not be likely to lead to continuation or... was given by posting copies of the notice in the Office of the Secretary, U.S. International Trade...

Mechanical properties of PET composites using multi-walled carbon nanotubes functionalized by inorganic and itaconic acids

Directory of Open Access Journals (Sweden)

A. May-Pat

2012-02-01

Full Text Available Multi-walled carbon nanotubes (MWCNTs were oxidized by two different acid treatments and further functionalized with itaconic acid (IA. The functionalized MWCNTs were used to fabricate Poly(ethylene terephthalate (PET composites by melt mixing. The presence of functional groups on the surface of the treated MWCNTs was confirmed by infrared spectroscopy and thermogravimetric analysis. The MWCNTs oxidized with a concentrated mixture of HNO3 and H2SO4 exhibited more oxygen containing functional groups (OH, COOH but also suffer larger structural degradation than those oxidized by a mild treatment based on diluted HNO3 followed by H2O2. PET composites were fabricated using the oxidized-only and oxidized followed by functionalization with IA MWCNTs. PET composites fabricated with MWCNT oxidized by mild conditions showed improved tensile strength and failure strain, while harsh MWCNT oxidation render them overly brittle.

Reciprocal effects of 5-(tetradecyloxy)-2-furoic acid on fatty acid oxidation.

Science.gov (United States)

Otto, D A; Chatzidakis, C; Kasziba, E; Cook, G A

1985-10-01

Under certain incubation conditions 5-(tetradecyloxy)-2-furoic acid (TOFA) stimulated the oxidation of palmitate by hepatocytes, as observed by others. A decrease in malonyl-CoA concentration accompanied the stimulation of oxidation. Under other conditions, however, TOFA inhibited fatty acid oxidation. The observed effects of TOFA depended on the TOFA and fatty acid concentrations, the cell concentration, the time of TOFA addition relative to the addition of fatty acid, and the nutritional state of the animal (fed or starved). The data indicate that only under limited incubation conditions may TOFA be used as an inhibitor of fatty acid synthesis without inhibition of fatty acid oxidation. When rat liver mitochondria were preincubated with TOFA, ketogenesis from palmitate was slightly inhibited (up to 20%) at TOFA concentrations that were less than that of CoA, but the inhibition became almost complete (up to 90%) when TOFA was greater than or equal to the CoA concentration. TOFA had only slight or no inhibitory effects on the oxidation of palmitoyl-CoA, palmitoyl(-)carnitine, or butyrate. Since TOFA can be converted to TOFyl-CoA, the data suggest that the inhibition of fatty acid oxidation from palmitate results from the decreased availability of CoA for extramitochondrial activation of fatty acids. These data, along with previous data of others, indicate that inhibition of fatty acid oxidation by CoA sequestration is a common mechanism of a group of carboxylic acid inhibitors. A general caution is appropriate with regard to the interpretation of results when using TOFA in studies of fatty acid oxidation.

The effect of layer-by-layer chitosan-hyaluronic acid coating on graft-to-bone healing of a poly(ethylene terephthalate) artificial ligament.

Science.gov (United States)

Li, Hong; Ge, Yunsheng; Zhang, Pengyun; Wu, Lingxiang; Chen, Shiyi

2012-01-01

Surface coating with an organic layer-by-layer self-assembled template of chitosan and hyaluronic acid on a poly(ethylene terephthalate) (PET) artificial ligament was designed for the promotion and enhancement of graft-to-bone healing after artificial ligament implantation in a bone tunnel. The results of in vitro culturing of MC3T3-E1 mouse osteoblastic cells supported the hypothesis that the layer-by-layer coating of chitosan and hyaluronic acid could promote the cell compatibility of grafts and could promote osteoblast proliferation. A rabbit extra-articular tendon-to-bone healing model was used to evaluate the effect of this kind of surface-modified stainless artificial ligament in vivo. The final results proved that this organic compound coating could significantly promote and enhance new bone formation at the graft-bone interface histologically and, correspondingly, the experimental group with coating had significantly higher biomechanical properties compared with controls at 8 weeks (P < 0.05).

Facile preparation of super-hydrophilic poly(ethylene terephthalate) fabric using dilute sulfuric acid under microwave irradiation

Energy Technology Data Exchange (ETDEWEB)

Xu, Fang [College of Textiles and Garments, Southwest University, Chongqing 400715 (China); Chongqing Engineering Research Center of Biomaterial Fiber and Modern Textile, Chongqing 400715 (China); Zhang, Guangxian, E-mail: zgx656472@sina.com.cn [College of Textiles and Garments, Southwest University, Chongqing 400715 (China); Chongqing Engineering Research Center of Biomaterial Fiber and Modern Textile, Chongqing 400715 (China); Zhang, Fengxiu [College of Chemistry and Chemical Engineering, Southwest University, Chongqing 400715 (China); Zhang, Yuansong [College of Textiles and Garments, Southwest University, Chongqing 400715 (China); Chongqing Engineering Research Center of Biomaterial Fiber and Modern Textile, Chongqing 400715 (China)

2015-09-15

Highlights: • A durable super-hydrophilic PET fabric was prepared using dilute H{sub 2}SO{sub 4} under microwave irradiation. • Dilute sulfuric acid was gradually concentrated enough to sulfonate PET fabric. • Microwave irradiation made PET fabric modification highly efficient. • The mechanical properties of modified PET fibers were kept well. • The method was novel, rapid, and eco-friendly. - Abstract: The hydrophilicity of a poly(ethylene terephthalate) (PET) fabric was greatly modified by using dilute sulfuric acid, which gradually became concentrated enough to sulfonate the fabric when microwave irradiation (MW) was applied. The modified PET fabric was super-hydrophilic. Modifying the fabric caused the water contact angle to decrease from 132.46 (for the unmodified fabric) to 0°, the water absorption rate to increase from 36.45 to 119.78%, and the capillary rise height to increase from 0.4 to 14.4 cm. The hydrophilicity of the modified PET fabric was not affected by washing it many times. Fourier transform infrared spectroscopy and X-ray photoelectron spectroscopy analyses showed that there were sulfonic acid groups on the modified fibers. Almost no difference between the surfaces of the unmodified and modified PET fibers was found using scanning electron microscopy. Analysis by differential scanning calorimetry showed that the unmodified and modified fabrics had similar thermostabilities. X-ray diffraction analysis of the crystalline structures of the unmodified and modified fibers showed that they were almost the same. The strength, elasticity, and rigidity of the unmodified fabric were retained by the modified fabric. The modified fabric had better dyeing properties than the unmodified fabric.

Fatty acid oxidation in skeletal and cardiac muscle

International Nuclear Information System (INIS)

Glatz, J.F.C.

1983-01-01

The biochemical investigations described in this thesis deal with two aspects of fatty acid oxidation in muscle: a comparison of the use of cell-free and cellular systems for oxidation measurements, and studies on the assay and the role of the fatty acid binding protein in fatty acid metabolism. The fatty acid oxidation rates are determined radiochemically by the sum of 14 CO 2 and 14 C-labeled acid-soluble products formed during oxidation of [ 14 C]-fatty acids. A radiochemical procedure for the assay of fatty acid binding by proteins is described. (Auth.)

On hydrazine oxidation in nitric acid media

International Nuclear Information System (INIS)

Zil'berman, B.Ya.; Lelyuk, G.A.; Mashkin, A.N.; Yasnovitskaya, A.L.

1988-01-01

Yield of products of radiolytic ( 60 Co gamma radiation) and chemical hydrazine (HZ) oxidation in nitric acid media is studied. Under radiolyte HZ oxidation by nitric acid hydrazoic acid, ammonia and nitrogen appear to be the reaction products. HN 3 yield maximum under HZN oxidation makes up ∼ 0.35 mol per a mol of oxiduzed HZN. Under chemical oxidation HZN is oxidized by HNO 3 according to reaction catalysed by technetium HN 3 yield makes up ∼ 0.35 mol per a mol of oxidized HZN. Radiation-chemical oxidation of HN 3 proceeds up to its complete decomposition, decomposition rate is comparable with HZ oxidation rate. Under the chemical oxidation HN 3 is more stable, it is slowly decomposed after complete HZ decomposition

The oxidation of PET track-etched membranes by hydrogen peroxide as an effective method to increase efficiency of UV-induced graft polymerization

Directory of Open Access Journals (Sweden)

Il'ya Korolkov

2015-12-01

Full Text Available In this article, we report on functionalization of track-etched membrane based on poly(ethylene terephthalate (PET TeMs oxidized by advanced oxidation systems and by grafting of acrylic acid using photochemical initiation technique for the purpose of increasing functionality thus expanding its practical application. Among advanced oxidation processes (H2O2/UV system had been chosen to introduce maximum concentration of carboxylic acid groups. Benzophenone (BP photo-initiator was first immobilized on the surfaces of cylindrical pores which were later filled with aq. acrylic acid solution. UV-irradiation from both sides of PET TeMs has led to the formation of grafted poly(acrylic acid (PAA chains inside the membrane nanochannels. Effect of oxygen-rich surface of PET TeMs on BP adsorption and subsequent process of photo-induced graft polymerization of acrylic acid (AA were studied by ESR. The surface of oxidized and AA grafted PET TeMs was characterized by UV-vis, ATR-FTIR, XPS spectroscopies and by SEM.

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.

Chemical recycling of post-consumer PET: structural characterization of terephthalic acid and the effect of Alkaline Hydrolysis at low temperature

International Nuclear Information System (INIS)

Fonseca, Talitha Granja; Almeida, Yeda Medeiros Bastos de; Vinhas, Gloria Maria

2014-01-01

Due to the environmental impact caused by PET packaging disposal, this material recycling has been thoroughly discussed and evaluated. In particular, chemical recycling enables achievement of the monomers that are used in PET resin manufacture: ethylene glycol (EG) and terephthalic acid (PTA). Therefore, studies for this process optimization are important from environmental and economic points of view. The present study investigated certain parameters that influence the depolymerization reaction of PET post-consumer via alkaline hydrolysis in order to obtain PTA. Assays were performed at 70 °C by varying the concentration of sodium hydroxide and the reaction time. The best results were obtained at 10.82 mol L -1 NaOH and 9 h reaction time. Consequently, it was possible to prove this process viability, once analyses by infrared and nuclear magnetic resonance confirmed that PTA was obtained in all reactions performed. (author)

Fatty acid omega-oxidation as a rescue pathway for fatty acid oxidation disorders in humans

NARCIS (Netherlands)

Wanders, Ronald J. A.; Komen, Jasper; Kemp, Stephan

2011-01-01

Fatty acids (FAs) can be degraded via different mechanisms including alpha-, beta- and omega-oxidation. In humans, a range of different genetic diseases has been identified in which either mitochondrial FA beta-oxidation, peroxisomal FA beta-oxidation or FA alpha-oxidation is impaired. Treatment

21 CFR 177.1315 - Ethylene-1, 4-cyclohexylene dimethylene terephthalate copolymers.

Science.gov (United States)

2010-04-01

... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Ethylene-1, 4-cyclohexylene dimethylene... Ethylene-1, 4-cyclohexylene dimethylene terephthalate copolymers. Ethylene-1, 4-cyclohexylene dimethylene... purposes of this section, ethylene-1,4-cyclohexylene dimethylene terephthalate copolymers (1,4-benzene...

Oxidative cleavage of erucic acid for the synthesis of brassylic acid

Energy Technology Data Exchange (ETDEWEB)

Mohammed J. Nasrullah; Pooja Thapliyal; Erica N. Pfarr; Nicholas S. Dusek; Kristofer L. Schiele; James A. Bahr

2010-10-29

The main focus of this work is to synthesize Brassylic Acid (BA) using oxidative cleavage of Erucic Acid (EA). Crambe (Crambe abyssinica) is an industrial oilseed grown in North Dakota. Crambe has potential as an industrial fatty acid feedstock as a source of Erucic acid (EA). It has approximately 50-60 % of EA, a C{sub 22} monounsaturated fatty acid. Oxidative cleavage of unsaturated fatty acids derived from oilseeds produces long chain (9, 11, and 13 carbon atoms) dibasic and monobasic acids. These acids are known commercial feedstocks for the preparation of nylons, polyesters, waxes, surfactants, and perfumes. Other sources of EA are Rapeseed seed oil which 50-60 % of EA. Rapeseed is grown outside USA. The oxidative cleavage of EA was done using a high throughput parallel pressure reactor system. Kinetics of the reaction shows that BA yields reach a saturation at 12 hours. H{sub 2}WO{sub 4} was found to be the best catalyst for the oxidative cleavage of EA. High yields of BA were obtained at 80 C with bubbling of O{sub 2} or 10 bar of O{sub 2} for 12 hours.

Hypochlorous and peracetic acid induced oxidation of dairy proteins.

Science.gov (United States)

Kerkaert, Barbara; Mestdagh, Frédéric; Cucu, Tatiana; Aedo, Philip Roger; Ling, Shen Yan; De Meulenaer, Bruno

2011-02-09

Hypochlorous and peracetic acids, both known disinfectants in the food industry, were compared for their oxidative capacity toward dairy proteins. Whey proteins and caseins were oxidized under well controlled conditions at pH 8 as a function of the sanitizing concentration. Different markers for protein oxidation were monitored. The results established that the protein carbonyl content was a rather unspecific marker for protein oxidation, which did not allow one to differentiate the oxidant used especially at the lower concentrations. Cysteine, tryptophan, and methionine were proven to be the most vulnerable amino acids for degradation upon hypochlorous and peracetic acid treatment, while tyrosine was only prone to degradation in the presence of hypochlorous acid. Hypochlorous acid induced oxidation gave rise to protein aggregation, while during peracetic acid induced oxidation, no high molecular weight aggregates were observed. Protein aggregation upon hypochlorous acid oxidation could primarily be linked to tryptophan and tyrosine degradation.

Controlled change of transport properties of poly(ethylene terephthalate) track membranes by plasma method

International Nuclear Information System (INIS)

Kravets, L I; Dmitriev, S N; Drachev, A I; Gilman, A B; Lazea, A; Dinescu, G

2007-01-01

A process of plasma polymerization of dimethylaniline and acrylic acid vapours on the surface of poly(ethylene terephthalate) track membranes has been investigated. The surface and hydrodynamic properties of the composite membranes produced in this case have been studied. It is shown that the water permeability of the obtained polymeric membranes can be controlled by changing the filtrate pH. Membranes with such properties can be used for controllable drug delivery and in sensor control

Acid-permanganate oxidation of potassium tetraphenylboron

International Nuclear Information System (INIS)

Smith, J.R.

1993-02-01

Scoping experiments have been performed which show that potassium tetraphenylboron (KTPB) is rapidly oxidized by permanganate in acidic solutions at room temperature. The main Products are CO 2 , highly oxidized organic compounds related to tartaric and tartronic acids, boric acid, and potassium phosphate (when phosphoric acid is used as the source of acid). One liter of 0.6M NaMnO 4 /2.5M H 3 PO 4 solution will destroy up to 8 grams of KTPB. The residual benzene concentration has been measured to be less than the RCRA limit of 0.5 ppm. Approximately 30% of the organic material is released as CO 2 (trace CO) and 0.16% as benzene vapor. The reaction is well behaved, no foaming or spattering. Tests were performed from .15M to near 1M permanganate. The phosphoric acid concentration was maintained at a concentration at least three times that of the permanganate since an excess of acid was desired and this is the ratio that these two reagents are consumed in the oxidation

Multiple Syntrophic Interactions in a Terephthalate-Degrading Methanogenic Consortium

Energy Technology Data Exchange (ETDEWEB)

Lykidis, Athanasios; Chen, Chia-Lung; Tringe, Susannah G.; McHardy, Alice C.; Copeland, Alex 5; Kyrpides, Nikos C.; Hugenholtz, Philip; Liu, Wen-Tso

2010-08-05

Terephthalate (TA) is one of the top 50 chemicals produced worldwide. Its production results in a TA-containing wastewater that is treated by anaerobic processes through a poorly understood methanogenic syntrophy. Using metagenomics, we characterized the methanogenic consortium tinside a hyper-mesophilic (i.e., between mesophilic and thermophilic), TA-degrading bioreactor. We identified genes belonging to dominant Pelotomaculum species presumably involved in TA degradation through decarboxylation, dearomatization, and modified ?-oxidation to H{sub 2}/CO{sub 2} and acetate. These intermediates are converted to CH{sub 4}/CO{sub 2} by three novel hyper-mesophilic methanogens. Additional secondary syntrophic interactions were predicted in Thermotogae, Syntrophus and candidate phyla OP5 and WWE1 populations. The OP5 encodes genes capable of anaerobic autotrophic butyrate production and Thermotogae, Syntrophus and WWE1 have the genetic potential to oxidize butyrate to COsub 2}/H{sub 2} and acetate. These observations suggest that the TA-degrading consortium consists of additional syntrophic interactions beyond the standard H{sub 2}-producing syntroph ? methanogen partnership that may serve to improve community stability.

Emulsifying Property and Antioxidative Activity of Cuttlefish Skin Gelatin Modified with Oxidized Linoleic Acid and Oxidized Tannic Acid

NARCIS (Netherlands)

Aewsiri, T.; Benjakul, S.; Visessanguan, W.; Wierenga, P.A.; Gruppen, H.

2013-01-01

Cuttlefish skin gelatins modified with oxidized linoleic acid (OLA) and oxidized tannic acid (OTA) were characterized and determined for emulsifying properties and antioxidative activity. Modification of gelatin with 5% OTA increased the total phenolic content and 1,1-diphenyl-2-picrylhydrazyl,

The radiation chemistry of aqueous sodium terephthalate solutions

International Nuclear Information System (INIS)

Matthews, R.W.

1980-04-01

The radiation chemistry of cobalt-60 gamma-irradiated aqueous sodium terephthalate solutions has been studied. In aerated 4 x 10 -4 M sodium hydroxide solutions, the main products are hydroxyterephthalate (HTA) (G = 0.99 +- 0.01), carbonate (G = 1.31 +- 0.08), and peroxides (G = 2.84 +- 0.04). The HTA and carbonate species are both formed as a result of hydroxyl radical attack and account for approximately 90 per cent of hydroxyl radical reactions. Oxygen needs to be present for efficient conversion of the terephthalate-OH radical adduct to HTA and oxygenation increases G(HTA) above the aerated solution value. G(HTA) is unaffected by changes in terephthalate concentration between 1 x 10 -4 M and 1 x 10 -2 M in sodium hydroxide solutions at pH 10. Decreasing the solution pH does however affect G(HTA). In phosphate buffered solutions pH 6.85, G(HTA) is 0.93 +- 0.01 and lower values are obtained with further decrease in solution pH. The lowering of the G(HTA) value is attributed to recombination reactions between the terephthalate-OH radical products and reducing radical products. Experimental evidence supporting the recombination postulate was obtained from the measurement of a parallel decrease in the peroxide yield and the observation of a dose rate effect on G(HTA). Competition kinetic studies with the added solutes carbonate and bicarbonate gave the rate ratios k (OH + TA 2- ) : k(OH + CO 3 2- ) : k(OH + HCO 3 - ) = 1 : 0.105 : 0.0036

Co-pyrolysis of rice straw and Polyethylene Terephthalate (PET) using a fixed bed drop type pyrolyzer

Science.gov (United States)

Izzatie, N. I.; Basha, M. H.; Uemura, Y.; Hashim, M. S. M.; Amin, N. A. M.; Hamid, M. F.

2017-10-01

In this work, co-pyrolysis of rice straw and polyethylene terephthalate (PET) was carried out at different temperatures (450,500,550, and 600°C) at ratio 1:1 by using fixed bed drop-type pyrolyzer. The purpose of this work is to determine the effect of pyrolysis temperature on the product yield. As the temperature increased, the pyrolysis oil increased until it reaches certain high temperature (600°C), the pyrolysis oil decreased as of more NCG were produced. The temperature 550°C is considered as the optimum pyrolysis temperature since it produced the highest amount of pyrolysis oil with 36 wt.%. In pyrolysis oil, the calorific value (13.98kJ/g) was low because of the presence of high water content (52.46 wt.%). Main chemicals group from pyrolysis oil were an aldehyde, ketones, acids, aromatics, and phenol and all compound have abundant of hydrogen and carbon were identified. Co-pyrolysis of rice straw and PET produced a higher amount of carbon oxides and recycling back the NCG could increase liquid and char yields.

Fatty acid oxidation and ketogenesis in astrocytes

International Nuclear Information System (INIS)

Auestad, N.

1988-01-01

Astrocytes were derived from cortex of two-day-old rat brain and grown in primary culture to confluence. The metabolism of the fatty acids, octanoate and palmitate, to CO 2 in oxidative respiration and to the formation of ketone bodies was examined by radiolabeled tracer methodology. The net production of acetoacetate was also determined by measurement of its mass. The enzymes in the ketogenic pathway were examined by measuring enzymic activity and/or by immunoblot analyses. Labeled CO 2 and labeled ketone bodies were produced from the oxidation of fatty acids labeled at carboxy- and ω-terminal carbons, indicating that fatty acids were oxidized by β-oxidation. The results from the radiolabeled tracer studies also indicated that a substantial proportion of the ω-terminal 4-carbon unit of the fatty acids bypassed the β-ketothiolase step of the β-oxidation pathway. The [ 14 C]acetoacetate formed from the [1- 14 C]labeled fatty acids, obligated to pass through the acetyl-CoA pool, contained 50% of the label at carbon 3 and 50% at carbon 1. In contrast, the [ 14 C]acetoacetate formed from the (ω-1)labeled fatty acids contained 90% of the label at carbon 3 and 10% at carbon 1

Acid monolayer functionalized iron oxide nanoparticle catalysts

Science.gov (United States)

Ikenberry, Myles

Superparamagnetic iron oxide nanoparticle functionalization is an area of intensely active research, with applications across disciplines such as biomedical science and heterogeneous catalysis. This work demonstrates the functionalization of iron oxide nanoparticles with a quasi-monolayer of 11-sulfoundecanoic acid, 10-phosphono-1-decanesulfonic acid, and 11-aminoundecanoic acid. The carboxylic and phosphonic moieties form bonds to the iron oxide particle core, while the sulfonic acid groups face outward where they are available for catalysis. The particles were characterized by thermogravimetric analysis (TGA), transmission electron microscopy (TEM), potentiometric titration, diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS), inductively coupled plasma optical emission spectrometry (ICP-OES), X-ray photoelectron spectrometry (XPS), and dynamic light scattering (DLS). The sulfonic acid functionalized particles were used to catalyze the hydrolysis of sucrose at 80° and starch at 130°, showing a higher activity per acid site than the traditional solid acid catalyst Amberlyst-15, and comparing well against results reported in the literature for sulfonic acid functionalized mesoporous silicas. In sucrose catalysis reactions, the phosphonic-sulfonic nanoparticles (PSNPs) were seen to be incompletely recovered by an external magnetic field, while the carboxylic-sulfonic nanoparticles (CSNPs) showed a trend of increasing activity over the first four recycle runs. Between the two sulfonic ligands, the phosphonates produced a more tightly packed monolayer, which corresponded to a higher sulfonic acid loading, lower agglomeration, lower recoverability through application of an external magnetic field, and higher activity per acid site for the hydrolysis of starch. Functionalizations with 11-aminoundecanoic acid resulted in some amine groups binding to the surfaces of iron oxide nanoparticles. This amine binding is commonly ignored in iron oxide

Parabanic acid is the singlet oxygen specific oxidation product of uric acid.

Science.gov (United States)

Iida, Sayaka; Ohkubo, Yuki; Yamamoto, Yorihiro; Fujisawa, Akio

2017-11-01

Uric acid quenches singlet oxygen physically or reacts with it, but the oxidation product has not been previously characterized. The present study determined that the product is parabanic acid, which was confirmed by LC/TOFMS analysis. Parabanic acid was stable at acidic pH (acid at neutral or alkaline pH. The total yields of parabanic acid and oxaluric acid based on consumed uric acid were ~100% in clean singlet oxygen production systems such as UVA irradiation of Rose Bengal and thermal decomposition of 3-(1,4-dihydro-1,4-epidioxy-4-methyl-1-naphthyl)propionic acid. However, the ratio of the amount of uric acid consumed to the total amount of singlet oxygen generated was less than 1/180, indicating that most of the singlet oxygen was physically quenched. The total yields of parabanic acid and oxaluric acid were high in the uric acid oxidation systems with hydrogen peroxide plus hypochlorite or peroxynitrite. They became less than a few percent in peroxyl radical-, hypochlorite- or peroxynitrite-induced oxidation of uric acid. These results suggest that parabanic acid could be an in vivo probe of singlet oxygen formation because of the wide distribution of uric acid in human tissues and extracellular spaces. In fact, sunlight exposure significantly increased human skin levels of parabanic acid.

Preparation of fulvic acid and low-molecular organic acids by oxidation of weathered coal humic acid

Energy Technology Data Exchange (ETDEWEB)

Shinozuka, T.; Ito, A.; Sasaki, O.; Yazawa, Y.; Yamaguchi, T. [Chiba Institute of Technolgy, Chiba (Japan). Dept. of Industrial Chemistry

2002-07-01

Weathered coal contains much humic acid and a little fulvic acid. Therefore, the production of fulvic acid, the most valuable humic substance because of its water-solubility, was examined by ozone and hydrogen peroxide oxidation of humic acid extracted form Xinjiang (China) weathered coal. The resulting products of the oxidation were water soluble fulvic acid and organic acids, mainly formic acid and oxalic acid. The product yield of fulvic acid was 20 (C%) and that of organic acids were 39 (C%) for formic and acid 13 (C%) for oxalic acid. The formed fulvic acid showed a higher content of oxygen and carboxyl groups, than those of the extracted one from the original weathered coal.

Formation of organic acids from trace carbon in acidic oxidizing media

International Nuclear Information System (INIS)

Terrassier, C.

2003-01-01

Carbon 14 does not fully desorb as CO 2 during the hot concentrated nitric acid dissolution step of spent nuclear fuel reprocessing: a fraction is entrained in solution into the subsequent process steps as organic species. The work described in this dissertation was undertaken to identify the compounds arising from the dissolution in 3 N nitric acid of uranium carbides (selected as models of the chemical form of carbon 14 in spent fuel) and to understand their formation and dissolution mechanism. The compounds were present at traces in solution, and liquid-solid extraction on a specific stationary phase (porous graphite carbon) was selected to concentrate the monoaromatic poly-carboxylic acids including mellitic acid, which is mentioned in the literature but has not been formally identified. The retention of these species and of oxalic acid - also cited in the literature - was studied on this stationary phase as a function of the mobile phase pH, revealing an ion exchange retention mechanism similar to the one observed for benzyltrimethylammonium polystyrene resins. The desorption step was then optimized by varying the eluent pH and ionic strength. Mass spectrometry analysis of the extracts identified acetic acid, confirmed the presence of mellitic acid, and revealed compounds of high molecular weight (about 200 g/mol); the presence of oxalic acid was confirmed by combining gas chromatography and mass spectrometry. Investigating the dissolution of uranium and zirconium carbides in nitric acid provided considerable data on the reaction and suggested a reaction mechanism. The reaction is self-catalyzing via nitrous acid, and the reaction rate de pends on the acidity and nitrate ion concentration in solution. Two uranium carbide dissolution mechanisms are proposed: one involves uranium at oxidation state +IV in solution, coloring the dissolution solution dark green, and the other assumes that uranium monocarbide is converted to uranium oxide. The carboxylic acid

Preparation of polymer blends from glycerol, fumaric acid and of poly(ethylene terephthalate) (PET) recycled

International Nuclear Information System (INIS)

Medeiros, Marina A.O.; Guimaraes, Danilo H.; Brioude, Michel M.; Jose, Nadia M.; Prado, Luis A.S. de A.

2011-01-01

Polymer blends based on recycled poly(ethylene terephthalate) (PET) and poly(glycerol fumarate) polyesters were prepared in different PET concentrations. The PET powder was dispersed during the poly(glycerol fumarate) synthesis at 260 deg C. The resulting blends were characterized by X-ray diffraction. The thermal stability of the materials was evaluated by thermogravimetric analysis and differential scanning calorimetry. The morphology was studies by scanning electron microscopy. The blends were clearly immiscible. The possibility of (interfacial) compatibilization of the PET domains, caused by transesterification reactions between PET and glycerol were discussed. (author)

Radiation-modified blends of the basis of polyethylene terephthalate and polypropylene

International Nuclear Information System (INIS)

Mery-Meri, R.; Revyakin, O.; Zicans, J.

2000-01-01

The binary composite systems on the basis of post-consumer poly-(ethylene terephthalate) and polypropylene have been investigated. Mechanical properties of the compositions were studied in detail in order to expand the application possibilities of tested binary composites. Structural changes of the poly (ethylene terephthalate) / polypropylene blends depending on the concentration of the components were investigated also. Additionally, the optimum processing conditions were established. Particular attention was paid to study the influence of the ionizing γ-radiation on the structural and mechanical properties of the composition systems tested. The magnitude of the adsorbed dose od γ-radiation was established to affect differently the structure of poly(ethylene terephalate) and polypropylene. At small absorbed doses (50 kGy) crosslinking of the polymer was observed for both poly(ethylene terephthalate) and polypropylene resulting in the increase of some mechanical properties of pure materials as well of their compositions, whereas the absorbed dose of 300 kGy caused the destruction of the tested materials. It is important to mention that the rate of radiation-chemical destruction of polypropylene is higher than poly(ethylene terephthalate) destruction rate. (author)

Up-cycling of PET (polyethylene terephthalate) to the biodegradable plastic PHA (polyhydroxyalkanoate).

Science.gov (United States)

Kenny, Shane T; Runic, Jasmina Nikodinovic; Kaminsky, Walter; Woods, Trevor; Babu, Ramesh P; Keely, Chris M; Blau, Werner; O'Connor, Kevin E

2008-10-15

The conversion of the petrochemical polymer polyethylene terephthalate (PET) to a biodegradable plastic polyhydroxyal-kanoate (PHA) is described here. PET was pyrolised at 450 degrees C resulting in the production of a solid, liquid, and gaseous fraction. The liquid and gaseous fractions were burnt for energy recovery, whereas the solid fraction terephthalic acid (TA) was used as the feedstock for bacterial production of PHA. Strains previously reported to grow on TA were unable to accumulate PHA. We therefore isolated bacteria from soil exposed to PET granules at a PET bottle processing plant From the 32 strains isolated, three strains capable of accumulation of medium chain length PHA (mclPHA) from TA as a sole source of carbon and energy were selected for further study. These isolates were identified using 16S rDNA techniques as P. putida (GO16), P. putida (GO19), and P. frederiksbergensis (GO23). P. putida GO16 and GO19 accumulate PHA composed predominantly of a 3-hydroxydecanoic acid monomer while P. frederiksbergensis GO23 accumulates 3-hydroxydecanoic acid as the predominant monomer with increased amounts of 3-hydroxydodecanoic acid and 3-hydroxydodecenoic acid compared to the other two strains. PHA was detected in all three strains when nitrogen depleted below detectable levels in the growth medium. Strains GO16 and GO19 accumulate PHA at a maximal rate of approximately 8.4 mg PHA/l/h for 12 h before the rate of PHA accumulation decreased dramatically. Strain GO23 accumulates PHA at a lower maximal rate of 4.4 mg PHA/l/h but there was no slow down in the rate of PHA accumulation over time. Each of the PHA polymers is a thermoplastic with the onset of thermal degradation occurring around 308 degrees C with the complete degradation occurring by 370 degrees C. The molecular weight ranged from 74 to 123 kDa. X-ray diffraction indicated crystallinity of the order of 18-31%. Thermal analysis shows a low glass transition (-53 degrees C) with a broad melting

Influence of Thermo-Oxidative Ageing on the Thermal and Dynamical Mechanical Properties of Long Glass Fibre-Reinforced Poly(Butylene Terephthalate) Composites Filled with DOPO.

Science.gov (United States)

Zhang, Daohai; He, Min; He, Weidi; Zhou, Ying; Qin, Shuhao; Yu, Jie

2017-05-04

In this work, the long glass fibre-reinforced poly(butylene terephthalate) (PBT) composites filled with 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide (DOPO) were prepared by melt blending, and the influence of thermo-oxidative ageing on the static and dynamic mechanical properties, thermal behaviours and morphology of composites with different ageing time at 120 °C were investigated and analysed. The results showed that the mechanical properties decreased in the primary stage of ageing, while embrittlement occurs in the later period, and the crystallinity of PBT decreases first, and then recovers to some extent. The scanning electron microscopy (SEM) photos of the samples indicated that the obvious crack appeared on the sample surface and a deeper, broader crack occurred with a longer ageing time. The results of energy dispersive X-ray analysis (EDAX) proved the DOPO filler diffused to the sample surface by measuring the content of phosphorus. Thermal gravimetric analysis (TGA) curves showed that the thermal stabilities of composites increased with longer ageing time, as did the values of the limited oxygen index (LOI). Meanwhile, the results of dynamic mechanical analysis (DMA) indicated that the glass transition temperature shifted to a higher temperature after ageing due to the effect of crosslinking, and both the crosslinking and degradation of PBT molecular chains act as the main factors in the whole process of thermo-oxidative ageing.

Relationships among oxidation-reduction and acid-base properties of the actinides in high oxidation states

International Nuclear Information System (INIS)

Morss, L.R.

1992-01-01

The first chemical identification of plutonium, its subsequent isolation on the macroscopic scale, and more recent chemical separation schemes were achieved by taking advantage of the differences among the oxidation states of uranium, neptunium, and plutonium. Many acid-base properties modify the relative stabilities of oxidation states of the actinides. In the solid state, strongly basic compounds such as Cs 2 O yield complex oxides with oxidation states of Np(VII), Pu(VI), and Am(VI) whereas more acidic compounds such as CsF yield complex fluorides with lower oxidation states. In aqueous solution, high basicity and strongly covalent complexes favor high oxidation states. In nonaqueous solvent systems, high acidity generally favors low oxidation states. This paper elucidates and attempts to interpret the effects of these acid-base properties in a systematic fashion

Macrokinetics of magnesium sulfite oxidation inhibited by ascorbic acid

International Nuclear Information System (INIS)

Lidong, Wang; Yongliang, Ma; Wendi, Zhang; Qiangwei, Li; Yi, Zhao; Zhanchao, Zhang

2013-01-01

Graphical abstract: Ascorbic acid is used as an inhibitor to retard the oxidation rate of magnesium sulfite. It shows that the oxidation rate would decrease greatly with the rise of initial ascorbic acid concentration, which provides a useful reference for sulfite recovery in magnesia desulfurization. -- Highlights: • We studied the kinetics of magnesium sulfite oxidation inhibited by ascorbic acid. • The oxidation process was simulated by a three-phase model and proved by HPLC–MS. • We calculated the kinetic parameters of intrinsic oxidation of magnesium sulfite. -- Abstract: Magnesia flue gas desulfurization is a promising process for small to medium scale industrial coal-fired boilers in order to reduce sulfur dioxide emissions, in which oxidation control of magnesium sulfite is of great importance for the recycling of products. Effects of four inhibitors were compared by kinetic experiments indicating that ascorbic acid is the best additive, which retards the oxidation process of magnesium sulfite in trace presence. The macrokinetics of magnesium sulfite oxidation inhibited by ascorbic acid were studied. Effects of the factors, including ascorbic acid concentration, magnesium sulfite concentration, oxygen partial pressure, pH, and temperature, were investigated in a stirred reactor with bubbling. The results show that the reaction rate is −0.55 order in ascorbic acid, 0.77 in oxygen partial pressure, and zero in magnesium sulfite concentration, respectively. The apparent activation energy is 88.0 kJ mol −1 . Integrated with the kinetic model, it is concluded that the oxidation rate of magnesium sulfite inhibited by ascorbic acid is controlled by the intrinsic chemical reaction. The result provides a useful reference for sulfite recovery in magnesia desulfurization

Effect of Oxidation Time on Humic Acid Yields

International Nuclear Information System (INIS)

Khin Thidar Cho; May Zin Lwin

2010-12-01

In this study,humic acids were produced from coal under controlled conditions by using different oxidation time. This research studies on the behaviour of coal during oxidation process. The coal used as raw material in this research was obtained from Ka Lay Wa, Sagaing Division . The coals were oxidized at the different oxidation times from 76 hr to 380 hr at the temperature 150 5C. The yields of humic acid, the ultimate analysis (percentage of carbon, hydrogen, nitrogen and oxygen) and the proximate analysis (percentage of volatile, ash and moisture) were done in this study. The functional groups and structural entities of the obtained humic acids were identified by using Fourier Transform Infrared Spectrophotometer (FTIR). The yield percentage of prepared humic acid in Ka Lay Wa coal was found to be 3%.

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.

Development of a bioprocess to convert PET derived terephthalic acid and biodiesel derived glycerol to medium chain length polyhydroxyalkanoate

Energy Technology Data Exchange (ETDEWEB)

Kenny, Shane T.; Nikodinovic Runic, Jasmina; O' Connor, Kevin E. [University College Dublin (Ireland). School of Biomolecular and Biomedical Sciences; Kaminsky, Walter [Hamburg Univ. (Germany). Inst. of Technical and Macromolecular Chemistry; Woods, Trevor; Babu, Ramesh P. [Dublin Univ. (Ireland). Materials Ireland Polymer Research Center

2012-08-15

Sodium terephthalate (TA) produced from a PET pyrolysis product and waste glycerol (WG) from biodiesel manufacture were supplied to Pseudomonas putida GO16 in a fed-batch bioreactor. Six feeding strategies were employed by altering the sequence of TA and WG feeding. P. putida GO16 reached 8.70 g/l cell dry weight (CDW) and 2.61 g/l PHA in 48 h when grown on TA alone. When TA and WG were supplied in combination, biomass productivity (g/l/h) was increased between 1.3- and 1.7-fold and PHA productivity (g/l/h) was increased 1.8- to 2.2-fold compared to TA supplied alone. The monomer composition of the PHA accumulated from TA or WG was predominantly composed of 3-hydroxydecanoic acid. PHA monomers 3-hydroxytetradeeanoic acid and 3-hydroxytetradecenoic acid were not present in PHA accumulated from TA alone but were present when WG was supplied to the fermentation. When WG was either the sole carbon source or the predominant carbon source supplied to the fermentation the molecular weight of PHA accumulated was lower compared to PHA accumulated when TA was supplied as the sole substrate. Despite similarities in data for the properties of the polymers, PHAs produced with WG present in the PHA accumulation phase were tacky while PHA produced where TA was the sole carbon substrate in the polymer accumulation phase exhibited little or no tackiness at room temperature. The co-feeding of WG to fermentations allows for increased utilisation of TA. The order of feeding of WG and TA has an effect on TA utilisation and polymer properties. (orig.)

Ethylenediammonium dication: H-bonded complexes with terephthalate, chloroacetate, phosphite, selenite and sulfamate anions. Detailed vibrational spectroscopic and theoretical studies of ethylenediammonium terephthalate

Science.gov (United States)

Marchewka, M. K.; Drozd, M.

2012-12-01

Crystalline complexes between ethylenediammonium dication and terephthalate, chloroacetate, phosphite, selenite and sulfamate anions were obtained by slow evaporation from water solution method. Room temperature powder infrared and Raman measurements were carried out. For ethylenediammonium terephthalate theoretical calculations of structure were performed by two ways: ab-initio HF and semiempirical PM3. In this case the PM3 method gave more accurate structure (closer to X-ray results). The additional PM3 calculations of vibrational spectra were performed. On the basis theoretical approach and earlier vibrational studies of similar compounds the vibrational assignments for observed bands have been proposed. All compounds were checked for second harmonic generation (SHG).

UV photodissociation spectroscopy of oxidized undecylenic acid films.

Science.gov (United States)

Gomez, Anthony L; Park, Jiho; Walser, Maggie L; Lin, Ao; Nizkorodov, Sergey A

2006-03-16

Oxidation of thin multilayered films of undecylenic (10-undecenoic) acid by gaseous ozone was investigated using a combination of spectroscopic and mass spectrometric techniques. The UV absorption spectrum of the oxidized undecylenic acid film is significantly red-shifted compared to that of the initial film. Photolysis of the oxidized film in the tropospheric actinic region (lambda > 295 nm) readily produces formaldehyde and formic acid as gas-phase products. Photodissociation action spectra of the oxidized film suggest that organic peroxides are responsible for the observed photochemical activity. The presence of peroxides is confirmed by mass-spectrometric analysis of the oxidized sample and an iodometric test. Significant polymerization resulting from secondary reactions of Criegee radicals during ozonolysis of the film is observed. The data strongly imply the importance of photochemistry in aging of atmospheric organic aerosol particles.

Textured surface boron-doped ZnO transparent conductive oxides on polyethylene terephthalate substrates for Si-based thin film solar cells

International Nuclear Information System (INIS)

Chen Xinliang; Lin Quan; Ni Jian; Zhang Dekun; Sun Jian; Zhao Ying; Geng Xinhua

2011-01-01

Textured surface boron-doped zinc oxide (ZnO:B) thin films were directly grown via low pressure metal organic chemical vapor deposition (LP-MOCVD) on polyethylene terephthalate (PET) flexible substrates at low temperatures and high-efficiency flexible polymer silicon (Si) based thin film solar cells were obtained. High purity diethylzinc and water vapors were used as source materials, and diborane was used as an n-type dopant gas. P-i-n silicon layers were fabricated at ∼ 398 K by plasma enhanced chemical vapor deposition. These textured surface ZnO:B thin films on PET substrates (PET/ZnO:B) exhibit rough pyramid-like morphology with high transparencies (T ∼ 80%) and excellent electrical properties (Rs ∼ 10 Ω at d ∼ 1500 nm). Finally, the PET/ZnO:B thin films were applied in flexible p-i-n type silicon thin film solar cells (device structure: PET/ZnO:B/p-i-n a-Si:H/Al) with a high conversion efficiency of 6.32% (short-circuit current density J SC = 10.62 mA/cm 2 , open-circuit voltage V OC = 0.93 V and fill factor = 64%).

Reaction kinetics of polybutylene terephthalate polycondensation reaction

NARCIS (Netherlands)

Darda, P. J.; Hogendoorn, J. A.; Versteeg, G. F.; Souren, F.

2005-01-01

The kinetics of the forward polycondensation reaction of polybutylene terephthalate (PBT) has been investigated using thermogravimetric analysis (TGA). PBT - prepolymer with an initial degree of polymerization of 5.5 was used as starting material. The PBT prepolymer was prepared from dimethyl

Inhibiting mitochondrial β-oxidation selectively reduces levels of nonenzymatic oxidative polyunsaturated fatty acid metabolites in the brain.

Science.gov (United States)

Chen, Chuck T; Trépanier, Marc-Olivier; Hopperton, Kathryn E; Domenichiello, Anthony F; Masoodi, Mojgan; Bazinet, Richard P

2014-03-01

Schönfeld and Reiser recently hypothesized that fatty acid β-oxidation is a source of oxidative stress in the brain. To test this hypothesis, we inhibited brain mitochondrial β-oxidation with methyl palmoxirate (MEP) and measured oxidative polyunsaturated fatty acid (PUFA) metabolites in the rat brain. Upon MEP treatment, levels of several nonenzymatic auto-oxidative PUFA metabolites were reduced with few effects on enzymatically derived metabolites. Our finding confirms the hypothesis that reduced fatty acid β-oxidation decreases oxidative stress in the brain and β-oxidation inhibitors may be a novel therapeutic approach for brain disorders associated with oxidative stress.

The kinetics of oxidation of bilirubin and ascorbic acid in solution

Science.gov (United States)

Solomonov, A. V.; Rumyantsev, E. V.; Kochergin, B. A.; Antina, E. V.

2012-07-01

The results of a comparative study of the oxidation of bilirubin, ascorbic acid, and their mixture in aqueous solutions under the action of air oxygen and hydrogen peroxide are presented. The observed and true rate constants for the oxidation reactions were determined. It was shown that the oxidation of tetrapyrrole pigment occurred under these conditions bypassing the stage of biliverdin formation to monopyrrole products. Simultaneous oxidation of bilirubin and ascorbic acid was shown to be accompanied by the inhibition of ascorbic acid oxidation by bilirubin, whereas ascorbic acid itself activated the oxidation of bilirubin.

Oxidation in fish oil enriched mayonnaise : Ascorbic acid and low pH increase oxidative deterioration

DEFF Research Database (Denmark)

Jacobsen, Charlotte; Timm Heinrich, Maike; Meyer, Anne S.

2001-01-01

The effect of ascorbic acid (0-4000 ppm) and pH (3.8-6.2) on oxidation and levels of iron and copper in various fractions of mayonnaise enriched with 16% fish oil was investigated. Ascorbic acid induced release of iron from the assumed oil- water interface into the aqueous phase at all pH levels......, but this effect of ascorbic acid was strongest at low pH (pH 3.8- 4.2). Ascorbic acid generally promoted formation of volatile oxidation compounds and reduced the peroxide value in mayonnaises. Peroxide values and total volatiles generally increased with decreasing pH values, suggesting that low pH promoted...... oxidation. It is proposed that iron bridges between the egg yolk proteins low-density lipoproteins, lipovitellin, and phosvitin at the oil-water interface are broken at low pH values, whereby iron ions become accessible as oxidation initiators. In the presence of ascorbic acid, oxidation is further enhanced...

Regularities of praseodymium oxide dissolution in acids

International Nuclear Information System (INIS)

Savin, V.D.; Elyutin, A.V.; Mikhajlova, N.P.; Eremenko, Z.V.; Opolchenova, N.L.

1989-01-01

The regularities of Pr 2 O 3 , Pr 2 O 5 and Pr(OH) 3 interaction with inorganic acids are studied. pH of the solution and oxidation-reduction potential registrated at 20±1 deg C are the working parameters of studies. It is found that the amount of all oxides dissolved increase in the series of acids - nitric, hydrochloric and sulfuric, in this case for hydrochloric and sulfuric acid it increases in the series of oxides Pr 2 O 3 , Pr 2 O 5 and Pr(OH) 3 . It is noted that Pr 2 O 5 has a high value of oxidation-reduction potential with a positive sign in the whole disslolving range. A low positive value of a redox potential during dissolving belongs to Pr(OH) 3 and in the case of Pr 2 O 3 dissloving redox potential is negative. The schemes of dissolving processes which do not agree with classical assumptions are presented

Influence of oxalic acid on the dissolution kinetics of manganese oxide

Science.gov (United States)

Godunov, E. B.; Artamonova, I. V.; Gorichev, I. G.; Lainer, Yu. A.

2012-11-01

The kinetics and electrochemical processes of the dissolution of manganese oxides with various oxidation states in sulfuric acid solutions containing oxalate ion additives is studied under variable conditions (concentration, pH, temperature). The parameters favoring a higher degree of the dissolution of manganese oxides in acidic media are determined. The optimal conditions are found for the dissolution of manganese oxides in acidic media in the presence of oxalate ions. The mechanism proposed for the dissolution of manganese oxides in sulfuric acid solutions containing oxalic acid is based on the results of kinetic and electrochemical studies. The steps of the dissolution mechanism are discussed.

Kinetics of Oxidation of Some Amino Acids by N-Chlorosaccharin in Aqueous Acetic Acid Medium

Directory of Open Access Journals (Sweden)

N. A. Mohamed Farook

2004-01-01

Full Text Available The kinetics of oxidation of some amino acids namely, glycine, alanine, aspartic acid, arginine, and histidine, (AA by N-chlorosaccharin (NCSA in aqueous acetic acid medium in the presence of perchloric acid have been investigated. The observed rate of oxidation is first order in [AA], [NCSA] and of inverse fractional order in [H+]. The main product of the oxidation is the corresponding aldehyde. The ionic strength on the reaction rate has no significant effect. The effect of changing the dielectric constant of the medium on the rate indicates the reaction to be of dipole-dipole type. Hypochlorous acid has been postulated as the reactive oxidizing species. The reaction constants involved in the mechanism are derived. The activation parameters are computed with respect to slow step of the mechanism.

Defective (U-14 C) palmitic acid oxidation in Duchenne muscular dystrophy

Energy Technology Data Exchange (ETDEWEB)

Carroll, J.E.; Norris, B.J.; Brooke, M.H.

1985-01-01

Compared with normal skeletal muscle, muscle from patients with Duchenne dystrophy had decreased (U-14 C) palmitic acid oxidation. (1-14 C) palmitic acid oxidation was normal. These results may indicate a defect in intramitochondrial fatty acid oxidation.

Defective [U-14 C] palmitic acid oxidation in Duchenne muscular dystrophy

International Nuclear Information System (INIS)

Carroll, J.E.; Norris, B.J.; Brooke, M.H.

1985-01-01

Compared with normal skeletal muscle, muscle from patients with Duchenne dystrophy had decreased [U-14 C] palmitic acid oxidation. [1-14 C] palmitic acid oxidation was normal. These results may indicate a defect in intramitochondrial fatty acid oxidation

Effect of calcium-ozone treatment on chemical and biological properties of polyethylene terephthalate.

Science.gov (United States)

Rashid, Ahmed Nafis; Tsuru, Kanji; Ishikawa, Kunio

2015-05-01

Ozone (O3 ) treatment of polyethylene terephthalate (PET) in distilled water was performed in the presence and absence of calcium (Ca(2+) ). PET was oxidized and thus carboxylic and hydroxyl functional groups were introduced on its surface after O3 treatment, regardless of the presence or absence of Ca(2+) . In the case of O3 treatment with Ca(2+) , PET surface was modified with Ca(2+) . Ca(2+) immobilization was confirmed by X-ray photoelectron spectrometric analysis. Hydrophilicity was investigated by measuring contact angles (CA). CA of PET decreased significantly after ozonation. Surface topography of PET before and after ozone treatment was observed by scanning electron microscopy, and showed no morphological changes. In vitro studies showed enhanced rat bone marrow cell responses on the O3 -treated PET surface. Ca(2+) -O3 oxidation at 37°C for 6 h is expected to be an effective method to fabricate PET with good biocompatibility. © 2014 Wiley Periodicals, Inc.

Nitric-phosphoric acid oxidation of organic waste materials

International Nuclear Information System (INIS)

Pierce, R.A.; Smith, J.R.

1995-01-01

A wet chemical oxidation technology has been developed to address issues facing defense-related facilities, private industry, and small-volume generators such as university and medical laboratories. Initially tested to destroy and decontaminate a heterogenous mixture of radioactive-contaminated solid waste, the technology can also remediate other hazardous waste forms. The process, unique to Savannah River, offers a valuable alternative to incineration and other high-temperature or high-pressure oxidation processes. The process uses nitric acid in phosphoric acid; phosphoric acid allows nitric acid to be retained in solution well above its normal boiling point. The reaction converts organics to carbon dioxide and water, and generates NO x vapors which can be recycled using air and water. Oxidation is complete in one to three hours. In previous studies, many organic compounds were completely oxidized, within experimental error, at atmospheric pressure below 180 degrees C; more stable compounds were decomposed at 200 degrees C and 170 kPa. Recent studies have evaluated processing parameters and potential throughputs for three primary compounds: EDTA, polyethylene, and cellulose. The study of polyvinylchloride oxidation is incomplete at this time

An anti-ferromagnetic terephthalate-bridged trigonal prismatic ...

Indian Academy of Sciences (India)

M. Scheme 1. Possible coordination modes of terephthalate. (tp). 2. ..... W and Atwood J L 2009 In Supramolecular Chemistry .... (a) Jiang Z Q, Zhao Z, Jiang G Y, Hou D C, Kang Y ... (a) Li H, Eddaoudi M, O'Keeffe M and Yaghi O M 1999.

Effects of Uric Acid on Exercise-induced Oxidative Stress

OpenAIRE

平井, 富弘

2001-01-01

We studied effects of uric acid on exercise― induced oxidative stress in humans based on a hypothesis that uric acid acts as an antioxidant to prevent from exercise―induced oxidative stress. Relation between uric acid level in plasma and increase of thiobarbituric acid reactive substance (TBARS)after the cycle ergometer exercise was examined. Thiobarbituricacid reactive substance in plasma increased after the ergometer exercise. High uric acid in plasma did not result in low increase of TBARS...

Studies on the biological oxidation - The oxidation of ascorbic acid (vitamin C) in biological fluids

OpenAIRE

Guzmán Barrón, E. S.; Guzmán Barrón, Alberto; Klemperer, Friedrich

2014-01-01

Biological fluids can be divided according to their behavior toward ascorbic acid into two groups: those having an inhibitory mechanism that protects the ascorbic acid oxidation, and those lacking this mechanism. Animal fluids and some of vegetable origin (those containing dosables amounts of ascorbic acid) corresponding to the first group. Ascorbic acid is protected from oxidation in the fluids by the action of copper catalyst. Fluids from plants (those that contain very little ascorbic acid...

Oxidation-extraction of uranium from wet-process phosphoric acid

International Nuclear Information System (INIS)

Lawes, B.C.

1985-01-01

The invention involves an improvement to the reductive stripping process for recovering uranium values from wet-process phosphoric acid solution, where uranium in the solution is oxidized to uranium (VI) oxidation state and then extracted from the solution by contact with a water immiscible organic solvent, by adding sufficient oxidant, hydrogen peroxide, to obtain greater than 90 percent conversion of the uranium to the uranium (VI) oxidation state to the phosphoric acid solution and simultaneously extracting the uranium (VI)

AMPK-independent pathways regulate skeletal muscle fatty acid oxidation

DEFF Research Database (Denmark)

Dzamko, Nicolas; Schertzer, Jonathan D.; Ryall, James G.

2008-01-01

The activation of AMP-activated protein kinase (AMPK) and phosphorylation/inhibition of acetyl-CoA carboxylase 2 (ACC2) is believed to be the principal pathway regulating fatty acid oxidation. However, during exercise AMPK activity and ACC Ser-221 phosphorylation does not always correlate...... with rates of fatty acid oxidation. To address this issue we have investigated the requirement for skeletal muscle AMPK in controlling aminoimidazole-4-carboxymide-1-beta-d-ribofuranoside (AICAR) and contraction-stimulated fatty acid oxidation utilizing transgenic mice expressing a muscle-specific kinase...... dead (KD) AMPK alpha2. In wild-type (WT) mice, AICAR and contraction increased AMPK alpha2 and alpha1 activities, the phosphorylation of ACC2 and rates of fatty acid oxidation while tending to reduce malonyl-CoA levels. Despite no activation of AMPK in KD mice, ACC2 phosphorylation was maintained...

Advanced oxidation processes of decomposing dichloroacetic acid and trichloroacetic acid in water

Institute of Scientific and Technical Information of China (English)

WANG Kun-ping; GUO Jin-song; YANG Min; JUNJI Hirotsuji; DENG Rong-sen; LIU Wei

2008-01-01

We studied the decomposition of two haloacetic acids (HAAs), dichloroacetic acid (DCAA) and trichloroacetic acid (TCAA), in water by single oxidants ozone (O3) and ultraviolet radiation (UV) and the advanced oxidation processes (AOPs) constituted by the combinations of O3/UV, H2O2/UV, O3 /H2O2, and O3/H2O2/UV. The concentrations of HAAs were analyzed at specified time intervals to track their decomposition. Except for O3 and UV, the four combined oxidation processes remarkably enhance the decomposition of DCAA and TCAA owing to the generated very reactive hydroxyl radicals. The fastest decomposition process is O3/H2O2/UV, closely followed by O3/UV. DCAA is much easier to decompose than TCAA. The kinetics of HAA decomposition by O3/UV can be described well by a pseudo first-order reaction model under a constant initial dissolved O3 concentration and fixed UV radiation. Humic acids and HCO3- in the reaction system both decrease the decomposition rate constants for DCAA and TCAA. The amount of H2O2 accumulates in the presence of humic acids in the O3/UV process.

76 FR 48122 - Polyethylene Terephthalate Film, Sheet, and Strip From Brazil: Preliminary Results of Antidumping...

Science.gov (United States)

2011-08-08

... on polyethylene terephthalate film, sheet, and strip (PET film) from Brazil. This administrative..., 2011. FOR FURTHER INFORMATION CONTACT: Deborah Scott or Robert James, AD/CVD Operations, Office 7... antidumping duty order on PET film from Brazil. See Polyethylene Terephthalate Film, Sheet, and Strip From...

Comparison of some aqueous chemical dosimeters for absorbed doses of less than 1000 rads. [Benzoic--salicylic acid, terephtalic--2-hydroxyterephtabe acid, ferrous sulfate--benzoic acid--xylenol orange, and standard Fricke dosimeter

Energy Technology Data Exchange (ETDEWEB)

Matthews, R W [Australian Atomic Energy Commission Research Establishment, Lucas Heights; Barker, N T; Sangster, D F

1978-01-01

This report gives the results of an investigation into the relative merits of the systems: benzoic-salicylic acid, terephthalic-2-hydroxyterephthalic acid, the more recent ferrous sulphate-benzoic acid-xylenol orange (FBX), and the standard Fricke dosimeter, for the measurement of absorbed doses under identical irradiation conditions, in the range 10 to 1000 rads.

Oxidative stability of fatty acid alkyl esters: a review.

Directory of Open Access Journals (Sweden)

Michal Angelovič

2015-12-01

Full Text Available The purpose of this study was to investigate and to process the current literary knowledge of the physico-chemical properties of vegetable oil raw used for biodiesel production in terms of its qualitative stability. An object of investigation was oxidative stability of biodiesel. In the study, we focused on the qualitative physico-chemical properties of vegetable oils used for biodiesel production, oxidative degradation and its mechanisms, oxidation of lipids, mechanisms of autooxidation, effectivennes of different synthetic antioxidants in relation to oxidative stability of biodiesel and methods of oxidative stability determination. Knowledge of the physical and chemical properties of vegetable oil as raw material and the factors affecting these properties is critical for the production of quality biodiesel and its sustainability. According to the source of oilseed, variations in the chemical composition of the vegetable oil are expressed by variations in the molar ratio among different fatty acids in the structure. The relative ratio of fatty acids present in the raw material is kept relatively constant after the transesterification reaction. The quality of biodiesel physico-chemical properties is influenced by the chain length and the level of unsaturation of the produced fatty acid alkyl esters. A biodiesel is thermodynamically stable. Its instability primarily occurs from contact of oxygen present in the ambient air that is referred to as oxidative instability. For biodiesel is oxidation stability a general term. It is necessary to distinguish ‘storage stability' and ‘thermal stability', in relation to oxidative degradation, which may occur during extended periods of storage, transportation and end use. Fuel instability problems can be of two related types, short-term oxidative instability and long-term storage instability. Storage instability is defined in terms of solid formation, which can plug nozzles, filters, and degrade engine

Surface pre-treatment for barrier coatings on polyethylene terephthalate

Science.gov (United States)

Bahre, H.; Bahroun, K.; Behm, H.; Steves, S.; Awakowicz, P.; Böke, M.; Hopmann, Ch; Winter, J.

2013-02-01

Polymers have favourable properties such as light weight, flexibility and transparency. Consequently, this makes them suitable for food packaging, organic light-emitting diodes and flexible solar cells. Nonetheless, raw plastics do not possess sufficient barrier functionality against oxygen and water vapour, which is of paramount importance for most applications. A widespread solution is to deposit thin silicon oxide layers using plasma processes. However, silicon oxide layers do not always fulfil the requirements concerning adhesion and barrier performance when deposited on films. Thus, plasma pre-treatment is often necessary. To analyse the influence of a plasma-based pre-treatment on barrier performance, different plasma pre-treatments on three reactor setups were applied to a very smooth polyethylene terephthalate film before depositing a silicon oxide barrier layer. In this paper, the influence of oxygen and argon plasma pre-treatments towards the barrier performance is discussed examining the chemical and topological change of the film. It was observed that a short one-to-ten-second plasma treatment can reduce the oxygen transmission rate by a factor of five. The surface chemistry and the surface topography change significantly for these short treatment times, leading to an increased surface energy. The surface roughness rises slowly due to the development of small spots in the nanometre range. For very long treatment times, surface roughness of the order of the barrier layer's thickness results in a complete loss of barrier properties. During plasma pre-treatment, the trade-off between surface activation and roughening of the surface has to be carefully considered.

Surface pre-treatment for barrier coatings on polyethylene terephthalate

International Nuclear Information System (INIS)

Bahre, H; Böke, M; Winter, J; Bahroun, K; Behm, H; Hopmann, Ch; Steves, S; Awakowicz, P

2013-01-01

Polymers have favourable properties such as light weight, flexibility and transparency. Consequently, this makes them suitable for food packaging, organic light-emitting diodes and flexible solar cells. Nonetheless, raw plastics do not possess sufficient barrier functionality against oxygen and water vapour, which is of paramount importance for most applications. A widespread solution is to deposit thin silicon oxide layers using plasma processes. However, silicon oxide layers do not always fulfil the requirements concerning adhesion and barrier performance when deposited on films. Thus, plasma pre-treatment is often necessary. To analyse the influence of a plasma-based pre-treatment on barrier performance, different plasma pre-treatments on three reactor setups were applied to a very smooth polyethylene terephthalate film before depositing a silicon oxide barrier layer. In this paper, the influence of oxygen and argon plasma pre-treatments towards the barrier performance is discussed examining the chemical and topological change of the film. It was observed that a short one-to-ten-second plasma treatment can reduce the oxygen transmission rate by a factor of five. The surface chemistry and the surface topography change significantly for these short treatment times, leading to an increased surface energy. The surface roughness rises slowly due to the development of small spots in the nanometre range. For very long treatment times, surface roughness of the order of the barrier layer's thickness results in a complete loss of barrier properties. During plasma pre-treatment, the trade-off between surface activation and roughening of the surface has to be carefully considered. (paper)

Prevalent mutations in fatty acid oxidation disorders

DEFF Research Database (Denmark)

Gregersen, N; Andresen, B S; Bross, P

2000-01-01

UNLABELLED: The mutational spectrum in a given disease-associated gene is often comprised of a large number of different mutations, of which a single or a few are present in a large proportion of diseased individuals. Such prevalent mutations are known in four genes of the fatty acid oxidation...... of the disease in question and determination of the carrier frequency in the general population may help in elucidating the penetrance of the genotype. This is exemplified in disorders of mitochondrial fatty acid oxidation....

78 FR 79400 - Polyethylene Terephthalate Film, Sheet, and Strip From the People's Republic of China: Initiation...

Science.gov (United States)

2013-12-30

... order on polyethylene terephthalate film, sheet, and strip (``PET film'') from the People's Republic of... INFORMATION CONTACT: Jonathan Hill, AD/CVD Operations, Office IV, Enforcement & Compliance, International... Operations, Office IV ``Initiation of Antidumping New Shipper Review of Polyethylene Terephthalate Film...

catalyzed oxidation of some amino acids by acid bromate

African Journals Online (AJOL)

Preferred Customer

ABSTRACT: Kinetic investigations on Pd(II) catalyzed oxidation of dl-serine and dl- ... A suitable mechanism in agreement with observed kinetics has been ..... In acidic solution of potassium bromate quick .... Annual Review of Biochemistry.

Fe-Catalyzed Oxidative Cleavage of Unsaturated Fatty Acids

NARCIS (Netherlands)

Spannring, P.

2013-01-01

The oxidative cleavage of unsaturated fatty acids into aldehydes or carboxylic acids gives access to valuable products. The products can be used as chemical building blocks, as emulsifiers or in the paint or polymer industry. Ozonolysis is applied industrially to cleave the fatty acid oleic acid

Aspects of the regulation of long-chain fatty acid oxidation in bovine liver

International Nuclear Information System (INIS)

Jesse, B.W.; Emery, R.S.; Thomas, J.W.

1986-01-01

Factors involved in regulation of bovine hepatic fatty acid oxidation were examined using liver slices. Fatty acid oxidation was measured as the conversion of l-[ 14 C] palmitate to 14 CO 2 and total [ 14 C] acid-soluble metabolites. Extended (5 to 7 d) fasting of Holstein cows had relatively little effect on palmitate oxidation to acid-soluble metabolites by liver slices, although oxidation to CO 2 was decreased. Feeding a restricted roughage, high concentrate ration to lactating cows resulted in inhibition of palmitate oxidation. Insulin, glucose, and acetate inhibited palmitate oxidation by bovine liver slices. The authors suggest the regulation of bovine hepatic fatty acid oxidation may be less dependent on hormonally induced alterations in enzyme activity as observed in rat liver and more dependent upon action of rumen fermentation products or their metabolites on enzyme systems involved in fatty acid oxidation

The oxidation of acid azo dye AY 36 by a manganese oxide containing mine waste

International Nuclear Information System (INIS)

Clarke, Catherine E.; Kielar, Filip; Johnson, Karen L.

2013-01-01

Highlights: ► This study looks at the oxidative breakdown of the amine containing dye acid yellow 36 by a Mn oxide containing mine waste. ► The oxidation proceeds by successive one electron transfers between the dye molecule and the Mn oxide minerals. ► The initial decolorization of the dye is rapid, but does not involve the cleavage of the azo bond. -- Abstract: The oxidative breakdown of acid azo dye acid yellow 36 (AY 36) by a Mn oxide containing mine tailings is demonstrated. The oxidation reaction is pH dependent with the rate of decolorization increasing with decreasing pH. The oxidation reaction mechanism is initiated at the amino moiety and proceeds via successive, one electron transfers from the dye to the Mn oxide minerals. The reaction pathway involves the formation of a number of colorless intermediate products, some of which hydrolyze in a Mn oxide-independent step. Decolorization of the dye is rapid and is observed before the cleavage of the azo-bond, which is a slower process. The terminal oxidation products were observed to be p-benzoquinone and 3-hydroxybenzenesulfonate. The reaction order of the initial decolorization was determined to be pseudo fractional order with respect to pH and pseudo first order with respect to dye concentration and Mn tailings’ surface area

78 FR 35245 - Polyethylene Terephthalate Film, Sheet, and Strip From the People's Republic of China: Final...

Science.gov (United States)

2013-06-12

... polyethylene terephthalate film, sheet, and strip (``PET film'') from the People's Republic of China (``PRC... Film, Sheet, and Strip From the People's Republic of China: Final Results of Antidumping Duty..., 2011. \\1\\ See Polyethylene Terephthalate Film, Sheet, and Strip From the People's Republic of China...

76 FR 76941 - Polyethylene Terephthalate Film, Sheet, and Strip From Taiwan: Final Results of Antidumping Duty...

Science.gov (United States)

2011-12-09

... on polyethylene terephthalate film, sheet and strip (PET Film) from Taiwan. The period of review (POR... Halle, AD/CVD Operations, Office 6, Import Administration, International Trade Administration, U.S... Results in the Administrative Review on Polyethylene Terephthalate Film, Sheet and Strip from Taiwan (PET...

Oxidative stability of Liposomes composed of docosahexaenoic acid-containing phospholipids

DEFF Research Database (Denmark)

Vikbjerg, Anders Falk; Andresen, Thomas Lars; Jørgensen, Kent

2007-01-01

Oxidative stability of liposomes made of (Docosahexaenoic acid) DHA-containing phosphatidylcholine (PC) was examined during preparation and storage. After preparation of the liposomes, the concentration of primary (conjugated dienes) and secondary oxidation products (Thiobarbituric acid...

Layered double hydroxide/polyethylene terephthalate nanocomposites. Influence of the intercalated LDH anion and the type of polymerization heating method

International Nuclear Information System (INIS)

Herrero, M.; Martinez-Gallegos, S.; Labajos, F.M.; Rives, V.

2011-01-01

Conventional and microwave heating routes have been used to prepare PET-LDH (polyethylene terephthalate-layered double hydroxide) composites with 1-10 wt% LDH by in situ polymerization. To enhance the compatibility between PET and the LDH, terephthalate or dodecyl sulphate had been previously intercalated in the LDH. PXRD and TEM were used to detect the degree of dispersion of the filler and the type of the polymeric composites obtained, and FTIR spectroscopy confirmed that the polymerization process had taken place. The thermal stability of these composites, as studied by thermogravimetric analysis, was enhanced when the microwave heating method was applied. Dodecyl sulphate was more effective than terephthalate to exfoliate the samples, which only occurred for the terephthalate ones under microwave irradiation. - Graphical abstract: Conventional and microwave heating routes were used to prepare PET-LDH (polyethylene terephthalate-layered double hydroxide) composites with 1-10 wt% LDH by in situ polymerization. To enhance the compatibility between PET and the LDH, terephthalate or dodecyl sulphate was previously intercalated into the LDH. The microwave process improves the dispersion and the thermal stability of nanocomposites due to the interaction of the microwave radiation and the dipolar properties of EG and the homogeneous heating. Highlights: → LDH-PET compatibility is enhanced by preintercalation of organic anions. → Dodecylsulphate performance is much better than that of terephthalate. → Microwave heating improves the thermal stability of the composites. → Microwave heating improves as well the dispersion of the inorganic phase.

Nitric-phosphoric acid oxidation of solid and liquid organic materials

International Nuclear Information System (INIS)

Pierce, R.A.; Smith, J.R.; Poprik, D.C.

1995-01-01

Nitric-phosphoric acid oxidation has been developed specifically to address issues that face the Savannah River Site, other defense-related facilities, private industry, and small-volume generators such as university and medical laboratories. Initially tested to destroy and decontaminate SRS solid, Pu-contaminated job-control waste, the technology has also exhibited potential for remediating hazardous and mixed-hazardous waste forms. The process is unique to Savannah River and offers a valuable alternative to other oxidation processes that require extreme temperatures and/or elevated pressures. To address the broad categories of waste, many different organic compounds which represent a cross-section of the waste that must be treated have been successfully oxidized. Materials that have been quantitatively oxidized at atmospheric pressure below 180 degrees C include neoprene, cellulose, EDTA, tributylphosphate, and nitromethane. More stable compounds such as benzoic acid, polyethylene, oils, and resins have been completely decomposed below 200 degrees C and 10 psig. The process uses dilute nitric acid in a concentrated phosphoric acid media as the main oxidant for the organic compounds. Phosphoric acid allow nitric acid to be retained in solution well above its normal boiling point. The reaction forms NOx vapors which can be reoxidized and recycled using air and water. The addition of 0.001M Pd(II) reduces CO generation to near 1% of the released carbon gases. The advantages of this process are that it is straightforward, uses relatively inexpensive reagents, operates at relatively low temperature and pressure, and produces final solutions which are compatible with stainless steel equipment. For organic wastes, all carbon, hydrogen, and nitrogen are converted to gaseous products. If interfaced with an acid recovery system which converts NOx back to nitric acid, the net oxidizer would be oxygen from air

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.

Poly(ether amide) segmented block copolymers with adipicacid based tetra amide segments

NARCIS (Netherlands)

Biemond, G.J.E.; Feijen, Jan; Gaymans, R.J.

2007-01-01

Poly(tetramethylene oxide)-based poly(ether ester amide)s with monodisperse tetraamide segments were synthesized. The tetraamide segment was based on adipic acid, terephthalic acid, and hexamethylenediamine. The synthesis method of the copolymers and the influence of the tetraamide concentration,

Effect of sulfonylureas on hepatic fatty acid oxidation

International Nuclear Information System (INIS)

Patel, T.B.

1986-01-01

In isolated rat livers perfused with oleic acid (0.1 mM), infusion of tolbutamide or glyburide decreased the rate of ketogenesis in a dose-dependent manner. The inhibition of fatty acid oxidation was maximal at 2.0 mM and 10 μM concentrations of tolbutamide and glyburide, respectively. Neither tolbutamide nor glyburide inhibited ketogenesis in livers perfused with octanoate. The inhibition of hepatic ketogenesis by sulfonylureas was independent of perfusate oleic acid concentration. Additionally, in rat livers perfused with oleic acid in the presence of L-(-)-carnitine (10 mM), submaximal concentrations of tolbutamide and glyburide did not inhibit hepatic ketogenesis. Finally, glyburide infusion into livers perfused with [U- 1 $C]oleic acid (0.1 mM) increased the rate of 14 C label incorporation into hepatic triglycerides by 2.5-fold. These data suggest that both tolbutamide and glyburide inhibit long-chain fatty acid oxidation by inhibition the key regulatory enzyme, carnitine palmitoyltransferase I, most probably by competing with L-(-)-carnitine

Chiral lewis Acid catalysis in nitrile oxide cycloadditions.

Science.gov (United States)

Sibi, Mukund P; Itoh, Kennosuke; Jasperse, Craig P

2004-05-05

We describe examples of highly regio- and enantioselective nitrile oxide cycloadditions to unsaturated alkenes using substoichiometric amounts of a chiral Lewis acid. Pyrazolidinones proved to be effective achiral templates in the cycloadditions providing C-adducts typically in >30:1 selectivity and 80-99% ee. To avoid potential problems involving coordination of the Lewis acid by amine bases, we have devised a novel method for the generation of unstable nitrile oxides from hydroximinoyl chlorides using Amberlyst 21 as the base.

Dynamic simulations on the mitochondrial fatty acid Beta-oxidation network

Directory of Open Access Journals (Sweden)

Weinberger Klaus M

2009-01-01

Full Text Available Abstract Background The oxidation of fatty acids in mitochondria plays an important role in energy metabolism and genetic disorders of this pathway may cause metabolic diseases. Enzyme deficiencies can block the metabolism at defined reactions in the mitochondrion and lead to accumulation of specific substrates causing severe clinical manifestations. Ten of the disorders directly affecting mitochondrial fatty acid oxidation have been well-defined, implicating episodic hypoketotic hypoglycemia provoked by catabolic stress, multiple organ failure, muscle weakness, or hypertrophic cardiomyopathy. Additionally, syndromes of severe maternal illness (HELLP syndrome and AFLP have been associated with pregnancies carrying a fetus affected by fatty acid oxidation deficiencies. However, little is known about fatty acids kinetics, especially during fasting or exercise when the demand for fatty acid oxidation is increased (catabolic stress. Results A computational kinetic network of 64 reactions with 91 compounds and 301 parameters was constructed to study dynamic properties of mitochondrial fatty acid β-oxidation. Various deficiencies of acyl-CoA dehydrogenase were simulated and verified with measured concentrations of indicative metabolites of screened newborns in Middle Europe and South Australia. The simulated accumulation of specific acyl-CoAs according to the investigated enzyme deficiencies are in agreement with experimental data and findings in literature. Investigation of the dynamic properties of the fatty acid β-oxidation reveals that the formation of acetyl-CoA – substrate for energy production – is highly impaired within the first hours of fasting corresponding to the rapid progress to coma within 1–2 hours. LCAD deficiency exhibits the highest accumulation of fatty acids along with marked increase of these substrates during catabolic stress and the lowest production rate of acetyl-CoA. These findings might confirm gestational loss to

Biodegradation of poly(lactic acid, poly(hydroxybutyrate-co-hydroxyvalerate, poly(butylene succinate and poly(butylene adipate-co-terephthalate under anaerobic and oxygen limited thermophilic conditions

Directory of Open Access Journals (Sweden)

Jutakan Boonmee

2016-01-01

Full Text Available In order to study the biodegradation behavior of biodegradable plastics in landfill conditions, four types of biodegradable plastics including poly(lactic acid (PLA, poly(hydroxybutyrate-co-hydroxyvalerate (PHBV, poly(butylene succinate (PBS, and poly(butylene adipate-co-terephthalate (PBAT were tested by burying in sludge mixed soil medium under anaerobic and oxygen limited conditions. The experiments were operated at 52 ± 2ºC in dark conditions according to ISO15985. The degree of biodegradation after 75 days was investigated by weight loss determination, visual examination, and surface appearance by scanning electronic microscopy (SEM. Under both anaerobic and oxygen limited conditions, the complete degradation (100% weight loss was found only in PHBV after 75 days. The plastic degradations were ranked in the order of PHBV> PLA> PBS> PBAT. The percentage of weight losses were significantly different at p ≤ 0.05. However, for all studied plastics, the degradation under anaerobic and oxygen limited conditions did not significantly different at 95% confidence.

CO2-selective PEO–PBT (PolyActive™)/graphene oxide composite membranes

KAUST Repository

Karunakaran, Madhavan; Shevate, Rahul; Kumar, Mahendra; Peinemann, Klaus-Viktor

2015-01-01

CO2-selective graphene oxide (GO) nano-composite membranes were prepared for the first time by embedding GO into a commercially available poly(ethylene oxide)–poly(butylene terephthalate) (PEO–PBT) copolymer (PolyActive™). The as-prepared GO membrane shows high CO2 permeability (143 Barrer) and CO2/N2 selectivity (α = 73).

CO2-selective PEO–PBT (PolyActive™)/graphene oxide composite membranes

KAUST Repository

Karunakaran, Madhavan

2015-07-31

CO2-selective graphene oxide (GO) nano-composite membranes were prepared for the first time by embedding GO into a commercially available poly(ethylene oxide)–poly(butylene terephthalate) (PEO–PBT) copolymer (PolyActive™). The as-prepared GO membrane shows high CO2 permeability (143 Barrer) and CO2/N2 selectivity (α = 73).

Preferential oxidation of linolenic acid compared to linoleic acid in the liver of catfish (Heteropneustes fossilis and Clarias batrachus)

International Nuclear Information System (INIS)

Bandyopadhyay, G.K.; Dutta, J.; Ghosh, S.

1982-01-01

The fate of [1(- 14 C] linoleic acid and [1( 14 C] linolenic acid in the liver slices and also in the liver tissues of live carnivorous catfish, Heteropneustes fossilis and Clarias batrachus, was studied. Incorporation of the fatty acids into different lipid classes in the live fish differed greatly from the tissue slices, indicating certain physiological control operative in vivo. The extent of desaturation and chain elongation of linoleic and linolenic acids into long-chain polyunsaturated fatty acids was low. Linolenic acid was oxidized (thus labeling the saturated fatty acid with liberated 14 C-acetyl-CoA) in preference to linoleic acid, and this oxidation also seemed to be under physiological control since both of the fatty acids were poorly oxidized in the tissue slices and in the killed fish. These fish can therefore recognize the difference in the acyl chain structures of linoleate and linolenate. The higher oxidation of linolenic acid and poor capacity for its conversion to longer chain, highly unsaturated derivatives indicates a higher demand for the dietary supply of these essential fatty acids in these two species

Kinetics of oxidic phase dissolution in acids

International Nuclear Information System (INIS)

Gorichev, I.G.; Kipriyanov, N.A.

1981-01-01

The critical analysis of the experimental data on dissolution kinetics of metal oxides (BeO, V 2 O 5 , UO 2 , Nb 2 O 5 , Ta 2 O 5 etc.) in acid media is carried out. Kinetic peculiarities of oxide dissolution are explained on the basis of the notions of electron- proton theory. It is established that the surface nonstoichiometric ccomposition of oxide phase and potential jump, appearing on the interface of the oxide-electrolyte phase are the important factors, determining the dissolution rate of a solid phase. The dissolution rate of metal oxides is limited by the transition of protons into the solid oxide phase. Morphological models of heterogeneous kinetics are used when explaining kinetic regularities of oxide dissolution process [ru

Enhancing the Dyeability of Polypropylene Fibers by Melt Blending with Polyethylene Terephthalate

Directory of Open Access Journals (Sweden)

Fereshteh Mirjalili

2013-01-01

Full Text Available Attempts were made to modify polypropylene fibers by melt blending with polyethylene terephthalate in order to enhance the dyeability of the resultant fiber. Five blends of polypropylene/polyethylene terephthalate/compatibilizer were prepared and subsequently spun into fibers. Three disperse dyes were used to dye such modified fibers at boiling and 130°C. The dyeing performance of the blend fibers, as well as the morphological, chemical, thermal, and mechanical properties, of the corresponding blends was characterized by means of spectrophotometry, polarized optical microscopy, scanning electron microscopy (SEM, FT-IR spectroscopy, differential scanning calorimetry (DSC, and tensile testing.

Novel method to deposit metal particles on transition metal oxide films and its application in lithium-ion batteries

International Nuclear Information System (INIS)

Pan Qinmin; Wang Min; Wang Hongbo; Zhao Jianwei; Yin Geping

2008-01-01

A novel method to modify the surfaces of transition metal oxides (MO) film-electrode was proposed in this study. At first, a monolayer of terephthalic acid was covalently bonded to the surfaces of Cu 2 O films. Then silver (Ag) particles were electrodeposited on the monolayer-grafted films by a potential-step process. The resulting Ag-Cu 2 O films exhibited improved electrochemical performance as negative electrodes in lithium-ion batteries compared to the original Cu 2 O films. An increase in electrical contact between Cu 2 O particles was considered to be responsible for the improvement in the electrochemical properties

THE COMBINED EFFECT OF ORGANIC PHOSPHINATE BASED FLAME RETARDANT AND ZINC BORATE ON THE FIRE BEHAVIOR OF POLY(BUTYLENE TEREPHTHALATE

Directory of Open Access Journals (Sweden)

Mustafa Erdem ÜREYEN

2016-12-01

Full Text Available Neat poly(butylene terephthalate is highly combustible. It is not self-extinguishing, and after ignition it burns with dripping. To meet the fire safety requirements, it should be rendered flame retardant. The most common flame retardants for PBT are based on halogenated (most often brominated or phosphorus compounds. Although their efficiency is lower than halogen based flame retardants, expensive phosphorus based flame retardants for polyester are preferred, because of low smoke generation, nontoxicity and low corrosion properties. Zinc borate has been widely used with other flame retardants in wood products and in several polymers. In this work the fire behavior of zinc borate, phosphinic acid and zinc borate/phosphinic acid combination doped poly(butylene terephthalate was investigated. Firstly, the mean particle size of zinc borate (2ZnO.3B2O3.3.5H2O powders were reduced by attrition milling. Samples were produced by twin screw micro compounder. The fire properties of the ZnB, DPA and ZnB/DPA doped PBT were investigated and compared to each other by LOI and thermal analysis. LOI values of ZnB/PBT samples were found very low even with higher filling content. At higher loading of ZnB, the dripping of the sample strongly decreased and char residue increased. It was seen that organic diethyl phosphinic acid based additives DPA is particularly effective with PBT. It was found that the combination of DPA and ZnB can be used to increase the char residue, decrease spread of flame and the melt dripping of PBT.

Nitrous Acid as an Oxidant in Acidic Media

Science.gov (United States)

1979-09-25

current work is the account of Ogsts and Sawski3 who studied the oxidation of benzyl ethers at 90C in acidic, aqueous dioxane. They found an increase in...and G. Tobin, Chem. Com., 180 (1978); (b) J. Hoggett , R. Moodie, and K. Schofield, Chem. Comm., 605 (1969). 15. (a) B. Challis and A. Lawson. J. Chem

Mechanism of catalytic action of oxide systems in reactions of aldehyde oxidation to carboxylic acids

International Nuclear Information System (INIS)

Andrushkevich, T.V.

1997-01-01

Mechanism of selective action of oxide catalysts (on the base of V 2 O 4 , MoO 3 ) of aldehyde oxidation to acids is considered, reaction acrolein oxidation to acrylic acid is taken as an example. Multistage mechanism of the process is established; it involves consequent transformation of coordination-bonded aldehyde into carbonyl-bonded aldehyde and symmetric carboxylate. Principles of active surface construction are formulated, they take into account the activity of stabilization center of concrete intermediate compound and bond energy of oxygen with surface. (author)

Kinetics and mechanism of the oxidation of formic and oxalic acids ...

Indian Academy of Sciences (India)

The oxidation of formic and oxalic acids by benzyltrimethylammonium dichloroiodate (BTMACI), in the presence of zinc chloride, leads to the formation of carbon dioxide. The reaction is first order with respect to BTMACI, zinc chloride and organic acid. Oxidation of deuteriated formic acid indicates the presence of a kinetic ...

Transformation of Unsaturated Fatty Acids/Esters to Corresponding Keto Fatty Acids/Esters by Aerobic Oxidation with Pd(II)/Lewis Acid Catalyst.

Science.gov (United States)

Senan, Ahmed M; Zhang, Sicheng; Zeng, Miao; Chen, Zhuqi; Yin, Guochuan

2017-08-16

Utilization of renewable biomass to partly replace the fossil resources in industrial applications has attracted attention due to the limited fossil feedstock with the increased environmental concerns. This work introduced a modified Wacker-type oxidation for transformation of unsaturated fatty acids/esters to the corresponding keto fatty acids/esters, in which Cu 2+ cation was replaced with common nonredox metal ions, that is, a novel Pd(II)/Lewis acid (LA) catalyst. It was found that adding nonredox metal ions can effectively promote Pd(II)-catalyzed oxidation of unsaturated fatty acids/esters to the corresponding keto fatty acids/esters, even much better than Cu 2+ , and the promotional effect is highly dependent on the Lewis acidity of added nonredox metal ions. The improved catalytic efficiency is attributed to the formation of heterobimetallic Pd(II)/LA species, and the oxidation mechanism of this Pd(II)/LA catalyst is also briefly discussed.

Synthesis of acetic acid by catalytic oxidation of butenes-2. Synthesis of acetic acid from sec. -butyl alcohol and methyl ethyl ketone in vapor-phase catalytic oxidation

Energy Technology Data Exchange (ETDEWEB)

Yamashita, T.; Matsuzawa, Y.; Ninagawa, S.

1977-11-01

Eleven binary catalysts containing vanadium pentoxide (V/sub 2/O/sub 5/), 17 binary catalysts containing cobalt oxide (Co/sub 3/O/sub 4/), and 18 ternary catalysts containing both V/sub 2/O/sub 5/ and Co/sub 3/O/sub 4/ were screened for the stepwise conversion of sec.-butanol to methyl ethyl ketone (MEK) and acetic acid. Of the binary catalysts, 4:1 Rh/V and Co/V binary oxides gave the best acetic acid yields. With the Co/V catalyst, the selectivity for MEK increased rapidly as the cobalt content of the catalyst increased above 50%, reaching 81% at 226/sup 0/C and 90% conversion on 9:1 Co/V oxide. The 9:1 Co/V catalyst also yielded acetaldehyde from ethanol with 98% selectivity at 210/sup 0/C and acetone from isopropanol with 98% selectivity at 200/sup 0/C, but dehydrated tert.-butanol to isobutene. V/Cr and V/Sb binary oxides were the most effective catalysts for the oxidation of MEK to acetic acid, with 78-88% selectivities at 100% conversion at 260/sup 0/C. Of the ternary oxides tested for the one-step conversion of sec.-butanol to acetic acid, a 6:2:2 Co/V/Al catalyst gave best results, (i.e., 34% selectivity for acetic acid (45% for total acids) at 100% conversion and 68% selectivity (90% for total acids) at 50Vertical Bar3< conversion). Graphs, tables, and 21 references.

Structure-Property of Metal Organic Frameworks Calcium Terephthalates Anodes for Lithium-ion Batteries

International Nuclear Information System (INIS)

Wang, Liping; Mou, Chengxu; Sun, Yang; Liu, Wei; Deng, Qijiu; Li, Jingze

2015-01-01

Graphical Abstract: Effects of hydration water in calcium terephthalates anodes on the structure, operational voltage and electrochemical performance are systematically studied. Display Omitted -- Highlights: •Metal organic frameworks CaC 8 H 4 O 4 ·3H 2 O and CaC 8 H 4 O 4 are applied as anodes for lithium ion batteries. •Appearance of hydration water leads different crystallography structures and electrochemical performance. •Anhydrous CaC 8 H 4 O 4 has a spacious ordered layer structure, a higher Ca-O chemical bonding interaction and a higher transparent lithium ion diffusion coefficient, delivering a higher capacity, better cycling performance and rate performance than CaC 8 H 4 O 4 ·3H 2 O. -- Abstract: Metal organic frameworks have attracted considerable interest as electrode materials for lithium ion batteries. In this paper, the metal organic frameworks hydrated calcium terephthalate (CaC 8 H 4 O 4 ·3H 2 O) and anhydrous calcium terephthalate (CaC 8 H 4 O 4 ) as anodes for lithium ion batteries are comparatively studied. Crystallography and local chemical bond analysis are combined to interpret the structure-property of calcium terephthalates. Results show that the anhydrous CaC 8 H 4 O 4 has a spacious ordered layer structure and a higher Ca-O chemical bonding interaction, delivering a higher capacity, better cycling performance and rate performance than CaC 8 H 4 O 4 ·3H 2 O

Oxidation of phenolic acid derivatives by soil and its relevance to allelopathic activity.

Science.gov (United States)

Ohno, T

2001-01-01

Previous studies have suggested that phenolic acids from legume green manures may contribute to weed control through allelopathy. The objectives of this study were to investigate the oxidation reactions of phenolic acids in soil and to determine the subsequent effects of oxidation upon phytotoxicity. Soils were reacted for 18 h with 0.25 mmol L(-1) benzoic and cinnamic acid derivative solutions and Mn release from the suspension was used as a marker for phenolic acid oxidation. The extent of oxidation in soil suspensions was in the order of 3,4dihydroxy- > 4-hydroxy-3-methoxy- > 4-hydroxy-approximately 2-hydroxy-substituted benzoic and cinnamic acids. The same ranking was observed for cyclic voltammetry peak currents of the cinnamic acid derivatives. This suggests that the oxidation of phenolic acids is controlled by the electron transfer step from the sorbed phenolic acid to the metal oxide. A bioassay experiment showed that the 4-hydroxy-, 4-hydroxy-3-methoxy-, and 3,4-dihydroxy-substituted cinnamic acids were bioactive at 0.25 mmol L(-1) concentration. Reaction with soil for 18 h resulted in the elimination of bioactivity of these three cinnamic acids at the 5% significance level. The oxidative reactivity of phenolic acids may limit the potential of allelopathy as a component of an integrated weed management system. However, the initial phytotoxicity after soil incorporation may coincide with the early, critical stage of weed emergence and establishment, so that allelopathic phenolic acids may still play a role in weed management despite their reactivity in soil systems.

Bezafibrate in skeletal muscle fatty acid oxidation disorders

DEFF Research Database (Denmark)

Ørngreen, Mette Cathrine; Madsen, Karen Lindhardt; Preisler, Nicolai

2014-01-01

OBJECTIVE: To assess whether bezafibrate increases fatty acid oxidation (FAO) and lowers heart rate (HR) during exercise in patients with carnitine palmitoyltransferase (CPT) II and very long-chain acyl-CoA dehydrogenase (VLCAD) deficiencies. METHODS: This was a 3-month, randomized, double......, triglyceride, and free fatty acid concentrations; however, there were no changes in palmitate oxidation, FAO, or HR during exercise. CONCLUSION: Bezafibrate does not improve clinical symptoms or FAO during exercise in patients with CPT II and VLCAD deficiencies. These findings indicate that previous in vitro...

Exposure to di-2-ethylhexyl terephthalate in a convenience sample of U.S. adults from 2000 to 2016.

Science.gov (United States)

Silva, Manori J; Wong, Lee-Yang; Samandar, Ella; Preau, James L; Calafat, Antonia M; Ye, Xiaoyun

2017-10-01

Di-2-ethylhexyl terephthalate (DEHTP), a structural isomer of di-2-ethylhexyl phthalate (DEHP), is a plasticizer used in a variety of commercial applications, but data on Americans' exposure to DEHTP do not exist. We investigated the exposure to DEHTP in a convenience group of U.S. adults by analyzing urine collected anonymously in 2000 (N = 44), 2009 (N = 61), 2011 (N = 81), 2013 (N = 92), and 2016 (N = 149) for two major DEHTP oxidative metabolites: mono-2-ethyl-5-carboxypentyl terephthalate (MECPTP) and mono-2-ethyl-5-hydroxyhexyl terephthalate (MEHHTP). For comparison, we also quantified the analogous DEHP metabolites mono-2-ethyl-5-hydroxyhexyl phthalate (MEHHP) and mono-2-ethyl-5-carboxypentyl phthalate (MECPP). We detected MECPTP, MEHHP, and MECPP in all samples collected in 2016 with geometric means of 13.1, 4.1, and 6.7 ng/mL, respectively; we detected MEHHTP in 91% of the samples (geometric mean = 3.1 ng/mL). Concentrations of MECPTP correlated well with those of MEHHTP (R 2  = 0.8, p  0.05) suggesting different sources of exposure to DEHP and DEHTP. We also evaluated the fraction of the metabolites eliminated in their free (i.e., unconjugated) form. The median percent of unconjugated species was lower for the DEHP metabolites (MECPP [45.5%], MEHHP [1.9%]) compared to the DEHTP metabolites (MECPTP [98.8%], MEHHTP [21.2%]). Contrary to the downward trend from 2000 to 2016 in urinary concentrations of MEHHP and MECPP, we observed an upward trend for MEHHTP and MECPTP. These preliminary data suggest that exposure to DEHTP may be on the rise. Nevertheless, general population exposure data using MEHHTP and MECPTP as exposure biomarkers would increase our understanding of exposure to DEHTP, one of the known DEHP alternatives.

Essential fatty acid-rich diets protect against striatal oxidative damage induced by quinolinic acid in rats.

Science.gov (United States)

Morales-Martínez, Adriana; Sánchez-Mendoza, Alicia; Martínez-Lazcano, Juan Carlos; Pineda-Farías, Jorge Baruch; Montes, Sergio; El-Hafidi, Mohammed; Martínez-Gopar, Pablo Eliasib; Tristán-López, Luis; Pérez-Neri, Iván; Zamorano-Carrillo, Absalom; Castro, Nelly; Ríos, Camilo; Pérez-Severiano, Francisca

2017-09-01

Essential fatty acids have an important effect on oxidative stress-related diseases. The Huntington's disease (HD) is a hereditary neurologic disorder in which oxidative stress caused by free radicals is an important damage mechanism. The HD experimental model induced by quinolinic acid (QUIN) has been widely used to evaluate therapeutic effects of antioxidant compounds. The aim of this study was to test whether the fatty acid content in olive- or fish-oil-rich diet prevents against QUIN-related oxidative damage in rats. Rats were fed during 20 days with an olive- or a fish-oil-rich diet (15% w/w). Posterior to diet period, rats were striatally microinjected with QUIN (240 nmol/µl) or saline solution. Then, we evaluated the neurological damage, oxidative status, and gamma isoform of the peroxisome proliferator-activated receptor (PPARγ) expression. Results showed that fatty acid-rich diet, mainly by fish oil, reduced circling behavior, prevented the fall in GABA levels, increased PPARγ expression, and prevented oxidative damage in striatal tissue. In addition none of the enriched diets exerted changes neither on triglycerides or cholesterol blood levels, nor or hepatic function. This study suggests that olive- and fish-oil-rich diets exert neuroprotective effects.

Kinetics of Oxidation of 3-Benzoylpropionic Acid by N-Bromoacetamide in Aqueous Acetic Acid Medium

Directory of Open Access Journals (Sweden)

N. A. Mohamed Farook

2011-01-01

Full Text Available The kinetics of oxidation of 3-benzoylpropionic acid (KA with N-bromoacetamide (NBA have been studied potentiometrically in 50:50 (v/v aqueous acetic acid medium at 298 K The reaction was first order each with respect to [KA], [NBA] and [H+]. The main product of the oxidation is the corresponding carboxylic acid. The rate decreases with the addition of acetamide, one of the products of the reaction. Variation in ionic strength of the reaction medium has no significant effect on the rate of oxidation. But the rate of the reaction is enhanced by lowering the dielectric constant of the reaction medium. A mechanism consistent with observed results have been proposed and the related rate law was deduced.

Branched Chain Amino Acid Oxidation in Cultured Rat Skeletal Muscle Cells

Science.gov (United States)

Pardridge, William M.; Casanello-Ertl, Delia; Duducgian-Vartavarian, Luiza

1980-01-01

Leucine metabolism in skeletal muscle is linked to protein turnover. Since clofibrate is known both to cause myopathy and to decrease muscle protein content, the present investigations were designed to examine the effects of acute clofibrate treatment on leucine oxidation. Rat skeletal muscle cells in tissue culture were used in these studies because cultivated skeletal muscle cells, like muscle in vivo, have been shown to actively utilize branched chain amino acids and to produce alanine. The conversion of [1-14C]leucine to 14CO2 or to the [1-14C]keto-acid of leucine (α-keto-isocaproate) was linear for at least 2 h of incubation; the production of 14CO2 from [1-14C]leucine was saturable with a Km = 6.3 mM and a maximum oxidation rate (Vmax) = 31 nmol/mg protein per 120 min. Clofibric acid selectively inhibited the oxidation of [1-14C]leucine (Ki = 0.85 mM) and [U-14C]isoleucine, but had no effect on the oxidation of [U-14C]glutamate, -alanine, -lactate, or -palmitate. The inhibition of [1-14C]leucine oxidation by clofibrate was also observed in the rat quarter-diaphragm preparation. Clofibrate primarily inhibited the production of 14CO2 and had relatively little effect on the production of [1-14C]keto-acid of leucine. A physiological concentration—3.0 g/100 ml—of albumin, which actively binds clofibric acid, inhibited but did not abolish the effects of a 2-mM concentration of clofibric acid on leucine oxidation. Clofibrate treatment stimulated the net consumption of pyruvate, and inhibited the net production of alanine. The drug also increased the cytosolic NADH/NAD+ ratio as reflected by an increase in the lactate/pyruvate ratio, in association with a decrease in cell aspartate levels. The changes in pyruvate metabolism and cell redox state induced by the drug were delayed compared with the nearly immediate inhibition of leucine oxidation. These studies suggest that clofibric acid, in concentrations that approximate high therapeutic levels of the drug

Micelle-assisted signaling of peracetic acid by the oxidation of pyreneboronic acid via monomer-excimer switching.

Science.gov (United States)

Choi, Jiyoung; Lee, Hyo Jin; Cho, Min Jeoung; Chang, Suk-Kyu

2015-08-15

A simple fluorescent probe for the industrial oxidant peracetic acid (PAA) was investigated. PAA-assisted oxidative conversion of pyrene-1-boronic acid into 1-hydroxypyrene was used as the signaling tool. Pyreneboronic acid was found to display selective signaling behavior, being more responsive to PAA than to other commonly used practical oxidants such as H2O2 and HOCl. The changes in pyrene monomer fluorescence to excimer were used in the quantitative analysis of PAA. When using the surfactant hexadecyltrimethylammonium bromide as a micellar additive, the signaling of PAA was markedly enhanced. Selective fluorescence signaling of PAA by pyrene-1-boronic acid with a detection limit of 1.5×10(-6)M in aqueous environment was successfully achieved. Copyright © 2015 Elsevier B.V. All rights reserved.

Formic acid oxidation at platinum-bismuth catalysts

Directory of Open Access Journals (Sweden)

Popović Ksenija Đ.

2015-01-01

Full Text Available The field of heterogeneous catalysis, specifically catalysis on bimetallic surfaces, has seen many advances over the past few decades. Bimetallic catalysts, which often show electronic and chemical properties that are distinct from those of their parent metals, offer the opportunity to obtain new catalysts with enhanced selectivity, activity, and stability. The oxidation of formic acid is of permanent interest as a model reaction for the mechanistic understanding of the electrooxidation of small organic molecules and because of its technical relevance for fuel cell applications. Platinum is one of the most commonly used catalysts for this reaction, despite the fact that it shows a few significant disadvantages: high cost and extreme susceptibility to poisoning by CO. To solve this problem, several approaches have been used, but generally, they all consist in the modification of platinum with a second element. Especially, bismuth has received significant attention as Pt modifier. According to the results presented in this survey dealing with the effects influencing the formic acid oxidation it was found that two types of Pt-Bi bimetallic catalysts (bulk and low loading deposits on GC showed superior catalytic activity in terms of the lower onset potential and oxidation current density, as well as exceptional stability compared to Pt. The findings in this report are important for the understanding of mechanism of formic acid electrooxidation on a bulk alloy and decorated surface, for the development of advanced anode catalysts for direct formic acid fuel cells, as well as for the synthesis of novel low-loading bimetallic catalysts. The use of bimetallic compounds as the anode catalysts is an effective solution to overcoming the problems of the formic acid oxidation current stability for long term applications. In the future, the tolerance of both CO poisoning and electrochemical leaching should be considered as the key factors in the development

Analysis of Chlorogenic Acid Oxidation Pathway in Simulated ...

African Journals Online (AJOL)

Keywords: Honeysuckle, Chlorogenic acid, Enzymatic browning, Mimic system, Oxidation pathway, ... enzymatic oxidation of CA is the major cause of ..... to the concentration of catechol, o-quinone and current at PPO-modified microcylinder biosensor for diffusion- kinetic model. J Electroanal Chem 2011; 660: 200-208.

The rationale for preventing cancer cachexia: targeting excessive fatty acid oxidation.

Science.gov (United States)

Qian, Chao-Nan

2016-07-21

Cachexia commonly occurs at the terminal stage of cancer and has largely unclear molecular mechanisms. A recent study published in Nature Medicine, entitled "Excessive fatty acid oxidation induces muscle atrophy in cancer cachexia," reveals that cachectic cancer cells can secrete multiple cytokines that induce excessive fatty acid oxidation, which is responsible for muscle loss in cancer cachexia. Inhibition of fatty acid oxidation using etomoxir can increase muscle mass and body weight in cancer cachexia animal models. The usage of stable cachexia animal models is also discussed in this research highlight.

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...

Wearable supercapacitors on polyethylene terephthalate fabrics with good wash fastness and high flexibility

Science.gov (United States)

Wang, Guixia; Babaahmadi, Vahid; He, Nanfei; Liu, Yixin; Pan, Qin; Montazer, Majid; Gao, Wei

2017-11-01

All solid-state micro-supercapacitors (MSC) have emerged as attractive energy-storage units for portable and wearable electronics. Here, we describe a textile-based solid-state MSC via laser scribing of graphene oxide (GO) coatings on a flexible polyethylene terephthalate (PET) fabric. The laser-scribed graphene oxide layers (LGO) possess three-dimensionally porous structure suitable for electrochemical-double-layer formation. To improve the wash fastness and the flexibility of the as-prepared MSCs, glutaraldehyde (GA) was employed to crosslink the GO layers and PVA-gel electrolyte onto the PET fabric. The resultant all solid-state MSCs exhibited excellent flexibility, high areal specific capacitance (756 μF·cm-2 at 20 mV·s-1), and good rate capability when subject to bending and laundering. Furthermore, the MSC device showed a high power density of about 1.4 W·cm-3 and an energy density of 5.3 × 10-5 Wh·cm-3, and retained 98.3% of its initial capacitance after 1000 cycles at a current density of 0.5 mA·cm-2. This work is the first demonstration of in-plane MSCs on PET fabric surfaces with enhanced durability and flexibility.

Molecular structure and vibrational spectra of Bis(melaminium) terephthalate dihydrate: A DFT computational study

Science.gov (United States)

Tanak, Hasan; Marchewka, Mariusz K.; Drozd, Marek

2013-03-01

The experimental and theoretical vibrational spectra of Bis(melaminium) terephthalate dihydrate were studied. The Fourier transform infrared (FT-IR) spectra of the Bis(melaminium) terephthalate dihydrate and its deuterated analogue were recorded in the solid phase. The molecular geometry and vibrational frequencies of Bis(melaminium) terephthalate dihydrate in the ground state have been calculated by using the density functional method (B3LYP) with 6-31++G(d,p) basis set. The results of the optimized molecular structure are presented and compared with the experimental X-ray diffraction. The molecule contains the weak hydrogen bonds of Nsbnd H⋯O, Nsbnd H⋯N and Osbnd H⋯O types, and those bonds are calculated with DFT method. In addition, molecular electrostatic potential, frontier molecular orbitals and natural bond orbital analysis of the title compound were investigated by theoretical calculations. The lack of the second harmonic generation (SHG) confirms the presence of macroscopic center of inversion.

Influence of pH-control in phosphoric acid treatment of zinc oxide

Energy Technology Data Exchange (ETDEWEB)

Onoda, H., E-mail: onoda@kpu.ac.jp [Department of Informatics and Environmental Sciences, Kyoto Prefectural University (Japan); Chemel, M. [Ecole de Biologie Industrielle, CERGY Cedex (France)

2017-04-15

Zinc oxide is often used as a white pigment for cosmetics; however, it shows photocatalytic activity that causes decomposition of sebum on the skin when exposed to the ultraviolet radiation in sunlight. In this work, zinc oxide was reacted with phosphoric acid at various pH values to synthesize a novel white pigment for cosmetics. The chemical composition, powder properties, photocatalytic activities, colors, and smoothness of these pigments were studied. The obtained materials exhibited X-ray diffraction peaks relating to zinc oxide and phosphate after phosphoric acid treatment. The ratio of zinc phosphate to zinc oxide was estimated from inductively coupled plasma - atomic emission spectroscopy results. Samples treated at pH 4-7 yielded small particles with sub-micrometer sizes. The photocatalytic activity of zinc oxide became lower after phosphoric acid treatment. Samples treated at pH 4-7 showed the same reflectance as zinc oxide in both the ultraviolet and visible ranges. Adjustment of the pH was found to be important in the phosphoric acid treatment of zinc oxide. (author)

Hepatic Fatty Acid Oxidation Restrains Systemic Catabolism during Starvation

Directory of Open Access Journals (Sweden)

Jieun Lee

2016-06-01

Full Text Available The liver is critical for maintaining systemic energy balance during starvation. To understand the role of hepatic fatty acid β-oxidation on this process, we generated mice with a liver-specific knockout of carnitine palmitoyltransferase 2 (Cpt2L−/−, an obligate step in mitochondrial long-chain fatty acid β-oxidation. Fasting induced hepatic steatosis and serum dyslipidemia with an absence of circulating ketones, while blood glucose remained normal. Systemic energy homeostasis was largely maintained in fasting Cpt2L−/− mice by adaptations in hepatic and systemic oxidative gene expression mediated in part by Pparα target genes including procatabolic hepatokines Fgf21, Gdf15, and Igfbp1. Feeding a ketogenic diet to Cpt2L−/− mice resulted in severe hepatomegaly, liver damage, and death with a complete absence of adipose triglyceride stores. These data show that hepatic fatty acid oxidation is not required for survival during acute food deprivation but essential for constraining adipocyte lipolysis and regulating systemic catabolism when glucose is limiting.

Experimental measurement and modelling of reactive species generation in TiO2 nanoparticle photocatalysis.

Science.gov (United States)

Turolla, Andrea; Piazzoli, Andrea; Budarz, Jeffrey Farner; Wiesner, Mark R; Antonelli, Manuela

2015-07-01

The generation of reactive species in titanium dioxide (TiO 2 ) nanoparticle photocatalysis was assessed in a laboratory scale setup, in which P25 Aeroxide TiO 2 suspensions were photoactivated by means of UV-A radiation. Photogenerated holes and hydroxyl radicals were monitored over time by observing their selective reaction with probe compounds, iodide and terephthalic acid, respectively. TiO 2 aggregate size and structure were characterized over the reaction time. Reactive species quenching was then described by a model, accounting for radiative phenomena, TiO 2 nanoparticle aggregation and kinetic reactions. The interaction between iodide and photogenerated holes was influenced by iodide adsorption on TiO 2 surface, described by a Langmuir-Hinshelwood mechanism, whose parameters were studied as a function of TiO 2 concentration and irradiation time. Iodide oxidation was effectively simulated by modelling the reaction volume as a completely stirred two-dimensional domain, in which irradiation phenomena were described by a two-flux model and the steady state for reactive species was assumed. The kinetic parameters for iodide adsorption and oxidation were estimated and successfully validated in a different experimental setup. The same model was adapted to describe the oxidation of terephthalic acid by hydroxyl radicals. The kinetic parameters for terephthalic acid oxidation were estimated and validated, while the issues in investigating the interaction mechanisms among the involved species have been discussed. The sensitivity of operating parameters on model response was assessed and the most relevant parameters were highlighted.

Analysis of Chlorogenic Acid Oxidation Pathway in Simulated ...

African Journals Online (AJOL)

Purpose: To investigate the pathways involved in the oxidation of chlorogenic acid (CA) and phenol metabolism in honeysuckle buds. Methods: A model that mimics CA oxidation by honeysuckle polyphenol oxidase (PPO) by controlling the reaction temperature or reaction duration was employed, and the resulting products ...

Oxidative diversification of amino acids and peptides by small-molecule iron catalysis.

Science.gov (United States)

Osberger, Thomas J; Rogness, Donald C; Kohrt, Jeffrey T; Stepan, Antonia F; White, M Christina

2016-09-08

Secondary metabolites synthesized by non-ribosomal peptide synthetases display diverse and complex topologies and possess a range of biological activities. Much of this diversity derives from a synthetic strategy that entails pre- and post-assembly oxidation of both the chiral amino acid building blocks and the assembled peptide scaffolds. The vancomycin biosynthetic pathway is an excellent example of the range of oxidative transformations that can be performed by the iron-containing enzymes involved in its biosynthesis. However, because of the challenges associated with using such oxidative enzymes to carry out chemical transformations in vitro, chemical syntheses guided by these principles have not been fully realized in the laboratory. Here we report that two small-molecule iron catalysts are capable of facilitating the targeted C-H oxidative modification of amino acids and peptides with preservation of α-centre chirality. Oxidation of proline to 5-hydroxyproline furnishes a versatile intermediate that can be transformed to rigid arylated derivatives or flexible linear carboxylic acids, alcohols, olefins and amines in both monomer and peptide settings. The value of this C-H oxidation strategy is demonstrated in its capacity for generating diversity: four 'chiral pool' amino acids are transformed to twenty-one chiral unnatural amino acids representing seven distinct functional group arrays; late-stage C-H functionalizations of a single proline-containing tripeptide furnish eight tripeptides, each having different unnatural amino acids. Additionally, a macrocyclic peptide containing a proline turn element is transformed via late-stage C-H oxidation to one containing a linear unnatural amino acid.

Physiological effects of γ-linolenic acid and sesamin on hepatic fatty acid synthesis and oxidation.

Science.gov (United States)

Ide, Takashi; Iwase, Haruka; Amano, Saaya; Sunahara, Saki; Tachihara, Ayuka; Yagi, Minako; Watanabe, Tsuyoshi

2017-03-01

Interrelated effects of γ-linolenic acid (GLA) and sesamin, a sesame lignan, on hepatic fatty acid synthesis and oxidation were examined. Rats were fed experimental diets supplemented with 0 or 2 g/kg sesamin (1:1 mixture of sesamin and episesamin) and containing 100 g/kg of palm oil (saturated fat), safflower oil rich in linoleic acid, or oil of evening primrose origin containing 43% GLA (GLA oil) for 18 days. In rats fed sesamin-free diets, GLA oil, compared with other oils, increased the activity and mRNA levels of various enzymes involved in fatty acid oxidation, except for some instances. Sesamin greatly increased these parameters, and the enhancing effects of sesamin on peroxisomal fatty acid oxidation rate and acyl-CoA oxidase, enoyl-CoA hydratase and acyl-CoA thioesterase activities were more exaggerated in rats fed GLA oil than in the animals fed other oils. The combination of sesamin and GLA oil also synergistically increased the mRNA levels of some peroxisomal fatty acid oxidation enzymes and of several enzymes involved in fatty acid metabolism located in other cell organelles. In the groups fed sesamin-free diets, GLA oil, compared with other oils, markedly reduced the activity and mRNA levels of various lipogenic enzymes. Sesamin reduced all these parameters, except for malic enzyme, in rats fed palm and safflower oils, but the effects were attenuated in the animals fed GLA oil. These changes by sesamin and fat type accompanied profound alterations in serum lipid levels. This may be ascribable to the changes in apolipoprotein-B-containing lipoproteins. Copyright © 2016 Elsevier Inc. All rights reserved.

Electron-beam-induced conduction in polyethylene terephthalate films

Energy Technology Data Exchange (ETDEWEB)

Beckley, L M; Lewis, T J; Taylor, D M [University Coll. of North Wales, Bangor (UK). School of Electronic Engineering Science

1976-06-21

Measurements are reported of electron-beam-induced conduction in thin polyethylene terephthalate (PET) films for electron energies up to 10 keV. The ratio of induced dielectric current to incident beam current (the gain) is orders of magnitude less than unity over practically the whole range of beam penetration. This result is quite unlike that normally found for inorganic dielectrics where the gain will exceed unity and reach a maximum at or near full penetration. In spite of the very different gain characteristics it is shown that the model recently proposed by Nunes de Oliviera and Gross (J. App. Phys.; 46:3132 (1975)), and by Aris et al (IEE Conf. Publ. No.129.; 267 (1975) and J. Phys. C. Solid State Phys.; 9:797 (1976)) and applied to mica and tantalum oxide respectively is also applicable to PET. Use is made of the known carrier mobility and lifetime data for this polymer and it is shown that very large space-charge distortions of the field can be produced by the beam which may well account for the frequent sample failure experienced during the experiments. The work supports suggestions by earlier workers that the current in unirradiated PET is electrode limited and predicts the maximum (space-charge limited) current likely to occur in this polymer.

Non-toxic poly(ethylene terephthalate)/clay nanocomposites with enhanced barrier properties

KAUST Repository

Hayrapetyan, Suren; Kelarakis, Antonios; Estevez, Luis; Lin, Qin; Dana, Kausik; Chung, Yi-Lin; Giannelis, Emmanuel P.

2012-01-01

Motivated by the technological need for poly(ethylene terephthalate) materials with improved barrier properties together with the requirement for sustainability this study focuses on an eco-friendly sulfonated polyester as clay compatibilizer

Establishment of thermophilic anaerobic terephthalic acid degradation system through one-step temperature increase startup strategy - Revealed by Illumina Miseq Sequencing.

Science.gov (United States)

Ma, Kai-Li; Li, Xiang-Kun; Wang, Ke; Meng, Ling-Wei; Liu, Gai-Ge; Zhang, Jie

2017-10-01

Over recent years, thermophilic digestion was constantly focused owing to its various advantage over mesophilic digestion. Notably, the startup approach of thermophilic digester needs to be seriously considered as unsuitable startup ways may result in system inefficiency. In this study, one-step temperature increase startup strategy from 37 °C to 55 °C was applied to establish a thermophilic anaerobic system treating terephthalic acid (TA) contained wastewater, meanwhile, the archaeal and bacterial community compositions at steady periods of 37 °C and 55 °C during the experimental process was also compared using Illumina Miseq Sequencing. The process operation demonstrated that the thermophilic TA degradation system was successfully established at 55 °C with over 95% COD reduction. For archaea community, the elevation of operational temperature from 37 °C to 55 °C accordingly increase the enrichment of hydrogenotrophic methanogens but decrease the abundance of the acetotrophic ones. While for bacterial community, the taxonomic analysis suggested that Syntrophorhabdus (27.40%) was the dominant genus promoting the efficient TA degradation under mesophilic condition, whereas OPB95 (24.99%) and TA06 (14.01%) related populations were largely observed and probably take some crucial role in TA degradation under thermophilic condition. Copyright © 2017 Elsevier Ltd. All rights reserved.

[Studies on the oxidation reaction of octanol-2 with nitric acid by infrared spectroscopy].

Science.gov (United States)

Zhang, G; Zhao, G; Wang, Y; Zhang, Q; Zhang, S; Lu, F

1998-04-01

In this paper, the reaction process of oxidation of octanol-2 with nitric acid has been studied by IR spectroscopy. It is found that the main components of non-sapoifiable matter are different in different oxidation degrees. The relation between oxidation products and the amount of nitric acid are investigated,the reaction mechanism has also been studied. Experimental results show that the oxidation process of octanol-2 is as follows: first, octanol-2 is oxidated to octanone-2, or to nitrate, nitrite and nitrile copmpounds, then these compounds are reoxidated to caproic acid in the meantime some by-products, such as valeric, enanthic acids are also found in oxidated products.

Preparation and characterization of dialdehyde starch by one-step acid hydrolysis and oxidation.

Science.gov (United States)

Zuo, Yingfeng; Liu, Wenjie; Xiao, Junhua; Zhao, Xing; Zhu, Ying; Wu, Yiqiang

2017-10-01

Dialdehyde starch was prepared by one-step synthesis of acid hydrolysis and oxidation, using corn starch as the raw material, sodium periodate (NaIO 4 ) as the oxidant, and hydrochloric acid (HCl) as the acid solution. The prepared dialdehyde starch was characterized by Fourier transform infrared spectroscopy (FT-IR), X-ray photoelectron spectroscopy (XPS), and gel permeation chromatography (GPC). The results confirmed that oxidation occurred between the starch and NaIO 4 . The acid hydrolysis reaction reduced the molecular weight of starch and effectively improved the aldehyde group contents (92.7%). Scanning electron microscope (SEM) analysis indicated that the average particle size decreased after acid hydrolysis and oxidation reaction. X-ray diffraction (XRD) and thermal gravimetric analyzer (TGA) analysis demonstrated that the crystallinity of the obtained dialdehyde starch showed a downward trend and a decelerated thermal decomposition rate. The starch after acid hydrolysis and oxidation exhibited lower hot paste viscosity and higher reactivity. Copyright © 2017. Published by Elsevier B.V.

Acid-catalyzed kinetics of indium tin oxide etching

Energy Technology Data Exchange (ETDEWEB)

Choi, Jae-Hyeok; Kim, Seong-Oh; Hilton, Diana L. [School of Materials Science and Engineering, Nanyang Technological University, 50 Nanyang Avenue, 639798 (Singapore); Centre for Biomimetic Sensor Science, Nanyang Technological University, 50 Nanyang Drive, 637553 (Singapore); Cho, Nam-Joon, E-mail: njcho@ntu.edu.sg [School of Materials Science and Engineering, Nanyang Technological University, 50 Nanyang Avenue, 639798 (Singapore); Centre for Biomimetic Sensor Science, Nanyang Technological University, 50 Nanyang Drive, 637553 (Singapore); School of Chemical and Biomedical Engineering, Nanyang Technological University, 62 Nanyang Drive, 637459 (Singapore)

2014-08-28

We report the kinetic characterization of indium tin oxide (ITO) film etching by chemical treatment in acidic and basic electrolytes. It was observed that film etching increased under more acidic conditions, whereas basic conditions led to minimal etching on the time scale of the experiments. Quartz crystal microbalance was employed in order to track the reaction kinetics as a function of the concentration of hydrochloric acid and accordingly solution pH. Contact angle measurements and atomic force microscopy experiments determined that acid treatment increases surface hydrophilicity and porosity. X-ray photoelectron spectroscopy experiments identified that film etching is primarily caused by dissolution of indium species. A kinetic model was developed to explain the acid-catalyzed dissolution of ITO surfaces, and showed a logarithmic relationship between the rate of dissolution and the concentration of undisassociated hydrochloric acid molecules. Taken together, the findings presented in this work verify the acid-catalyzed kinetics of ITO film dissolution by chemical treatment, and support that the corresponding chemical reactions should be accounted for in ITO film processing applications. - Highlights: • Acidic conditions promoted indium tin oxide (ITO) film etching via dissolution. • Logarithm of the dissolution rate depended linearly on the solution pH. • Acid treatment increased ITO surface hydrophilicity and porosity. • ITO film etching led to preferential dissolution of indium species over tin species.

Medical effects of poly-ethylene terephthalate (PET) non-woven ...

African Journals Online (AJOL)

In this study, bamboo activated charcoal was mixed with acrylic resin in various proportions and deposited on poly-ethylene terephthalate (PET) non-woven fabrics. A series of characterizations were carried out to estimate the performances of PET non-woven fabrics such as far infrared ray emission, heat retention, negative ...

Formic Acid Oxidation at Platinum-Bismuth Clusters

DEFF Research Database (Denmark)

Lovic, J. D.; Stevanovic, S. I.; Tripkovic, D. V.

2014-01-01

of Pt, were characterized by AFM spectroscopy which indicated that Pt crystallizes preferentially onto previously formed Bi particles. The issue of Bi leaching (dissolution) from PtBi catalysts, and their catalytic effect alongside the HCOOH oxidation is rather unresolved. In order to control Bi....... Catalysts prepared in this way exhibit about 10 times higher activity for formic acid oxidation in comparison to pure Pt, as revealed both by potentiodynamic and quasy-potentiostatic measurements. This high activity is the result of well-balanced ensemble effect induced by Bi-oxide species interrupting Pt...

Toughening modification of poly(butylene terephthalate)/poly(ethylene terephthalate) blends by an epoxy-functionalized elastomer

Science.gov (United States)

Zhang, Weizhou; Wang, Kai; Yan, Wei; Guo, Weihong

2017-10-01

New toughened poly(butylene terephthalate) (PBT)/poly(ethylene terephthalate) (PET) (40/60 wt%) blends were obtained by melting with Glycidyl methacrylate grafted poly(ethylene octane) copolymer (POE-g-GMA), varying the POE-g-GMA content up to 20 wt%, in a twin-screw extruder, followed by injection molding. The influence of POE-g-GMA on the properties of the PBT/PET blends was investigated by mechanical testing, Fourier transform infrared (FT-IR) analysis, gel fractions analysis, dynamic mechanical analysis (DMA), differential scanning calorimetry (DSC) and scanning electronic microscopy (SEM). The mechanical testing results indicated that the incorporation of POE-g-GMA led to increases in the notched impact strength and decreases in the tensile strength, flexural strength, and flexural modulus. When POE-g-GMA content reached 20 wt%, the notched impact strength (8.0 kJ m-2) was achieved for the PBT/PET/POE-g-GMA blends. FT-IR results proved that some PBT/PET/POE-g-GMA copolymers were produced, which improved the compatibility between POE-g-GMA and the PBT/PET matrix. The extent of crosslinking was observed by gel fraction measurements. DMA results further testified chain-extending and micro-crosslink reactions occurred between POE-g-GMA and PBT/PET blends. In addition, the reactions induced by POE-g-GMA affected the crystallization behavior of PBT/PET blends obviously, as observed from DSC results. By means of SEM observation of the impact fracture surface morphology, and the discussion of the micro-crosslink reaction process between the epoxide-containing elastomers and PBT/PET matrix, the toughening mechanism was proposed to be taken into account the shear yielding of PBT/PET matrix and cavitation of elastomer particles.

Green reduction of graphene oxide by ascorbic acid

Science.gov (United States)

Khosroshahi, Zahra; Kharaziha, Mahshid; Karimzadeh, Fathallah; Allafchian, Alireza

2018-01-01

Graphene, a single layer of sp2-hybridized carbon atoms in a hexagonal (two-dimensional honey-comb) lattice, has attracted strong scientific and technological interest due to its novel and excellent optical, chemical, electrical, mechanical and thermal properties. The solution-processable chemical reduction of Graphene oxide (GO is considered as the most favorable method regarding mass production of graphene. Generally, the reduction of GO is carried out by chemical approaches using different reductants such as hydrazine and sodium borohydride. These components are corrosive, combustible and highly toxic which may be dangerous for personnel health and the environment. Hence, these reducing agents are not promising choice for reducing of graphene oxide (GO). As a consequence, it is necessary for further development and optimization of eco-friendly, natural reducing agent for clean and effective reduction of GO. Ascorbic acid, an eco-friendly and natural reducing agents, having a mild reductive ability and nontoxic property. So, the aim of this research was to green synthesis of GO with ascorbic acid. For this purpose, the required amount of NaOH and ascorbic acid were added to GO solution (0.5 mg/ml) and were heated at 95 °C for 1 hour. According to the X-ray powder diffraction (XRD), scanning electron microscopy (SEM), and electrochemical results, GO were reduced with ascorbic acid like hydrazine with better electrochemical properties and ascorbic acid is an ideal substitute for hydrazine in the reduction of graphene oxide process.

Clarithromycin, trimethoprim, and penicillin and oxidative nucleic acid modifications in humans

DEFF Research Database (Denmark)

Larsen, Emil List; Cejvanovic, Vanja; Kjaer, Laura Kofoed

2017-01-01

, phenoxymethylpenicillin (penicillin V), or placebo. Oxidative modifications were measured as 24-h urinary excretion of 8-oxo-7,8-dihydro-2′-deoxyguanosine (8-oxodG) and 8-oxo-7,8-dihydroguanosine (8-oxoGuo), and plasma levels of malondialdehyde before and after treatment as a measurement of DNA oxidation, RNA oxidation.......7% (95% CI: 5.8–37.6%), but did not influence urinary excretion of 8-oxoGuo. Penicillin V did not influence urinary excretion of 8-oxodG or 8-oxoGuo. None of the antibiotic drugs influenced plasma levels of malondialdehyde. Conclusion Clarithromycin significantly increases oxidative nucleic acid...... modifications. Increased oxidative modifications might explain some of clarithromycin's known adverse reactions. Trimethoprim significantly lowers DNA oxidation but not RNA oxidation. Penicillin V had no effect on oxidative nucleic acid modifications....

A method for measuring fatty acid oxidation in C. elegans

DEFF Research Database (Denmark)

Elle, Ida Coordt; Rødkær, Steven Vestergaard; Fredens, Julius

2012-01-01

The nematode C. elegans has during the past decade proven to be a valuable model organism to identify and examine molecular mechanisms regulating lipid storage and metabolism. While the primary approach has been to identify genes and pathways conferring alterations in lipid accumulation, only a few...... recent studies have recognized the central role of fatty acid degradation in cellular lipid homeostasis. In the present study, we show how complete oxidation of fatty acids can be determined in live C. elegans by examining oxidation of tritium-labeled fatty acids to tritiated H2O that can be measured......, the present methodology can be used to delineate the role of specific genes and pathways in the regulation of β-oxidation in C. elegans....

Ferrous Iron Oxidation by Thiobacillus ferrooxidans: Inhibition with Benzoic Acid, Sorbic Acid, and Sodium Lauryl Sulfate

OpenAIRE

Onysko, Steven J.; Kleinmann, Robert L. P.; Erickson, Patricia M.

1984-01-01

Benzoic acid, sorbic acid, and sodium lauryl sulfate at low concentrations (5 to 10 mg/liter) each effectively inhibited bacterial oxidation of ferrous iron in batch cultures of Thiobacillus ferrooxidans. The rate of chemical oxidation of ferrous iron in low-pH, sterile batch reactors was not substantially affected at the tested concentrations (5 to 50 mg/liter) of any of the compounds.

Remediation of TCE-contaminated groundwater using acid/BOF slag enhanced chemical oxidation.

Science.gov (United States)

Tsai, T T; Kao, C M; Wang, J Y

2011-04-01

The objective of this study was to evaluate the potential of applying acid/H(2)O(2)/basic oxygen furnace slag (BOF slag) and acid/S(2)O(8)(2-)/BOF slag systems to enhance the chemical oxidation of trichloroethylene (TCE)-contaminated groundwater. Results from the bench-scale study indicate that TCE oxidation via the Fenton-like oxidation process can be enhanced with the addition of BOF slag at low pH (pH=2-5.2) and neutral (pH=7.1) conditions. Because the BOF slag has iron abundant properties (14% of FeO and 6% of Fe(2)O(3)), it can be sustainably reused for the supplement of iron minerals during the Fenton-like or persulfate oxidation processes. Results indicate that higher TCE removal efficiency (84%) was obtained with the addition of inorganic acid for the activation of Fenton-like reaction compared with the experiments with organic acids addition (with efficiency of 10-15% lower) (BOF slag=10gL(-1); initial pH=5.2). This could be due to the fact that organic acids would compete with TCE for available oxidants. Results also indicate that the pH value had a linear correlation with the observed first-order decay constant of TCE, and thus, lower pH caused a higher TCE oxidation rate. Copyright © 2011 Elsevier Ltd. All rights reserved.

Oxidation of indole-3-acetic acid to oxindole-3-acetic acid by etiolated and green corn tissues

International Nuclear Information System (INIS)

Reinecke, D.

1989-01-01

Etiolated corn tissues oxidase indole-3-acetic acid (IAA) to oxindole-3-acetic acid (OxIAA). This oxidation results in loss of auxin activity and may plant a role in regulating IAA-stimulated growth. The enzyme has been partially purified and characterized and shown to require O 2 , and a heat-stable lipid-soluble corn factor which can be replaced by linolenic or linoleic acids in the oxidation of IAA. Corn oil was tested as a cofactor in the IAA oxidation reaction. Corn oil stimulated enzyme activity by 30% while trilinolein was inactive. The capacity of green tissue to oxidize IAA was examined by incubating leaf sections from 2 week old light-grown corn seedlings with 14 C-IAA. OxIAA and IAA were separated from other IAA metabolites on a 3 ml anion exchange column. Of the IAA taken up by the sections, 13% was oxidized to OxIAA. This is the first evidence that green tissue of corn may also regulate IAA levels by oxidizing IAA to OxIAA

Fatty Acid Incubation of Myotubues from Humans with Type 2 Diabetes Leads to Enhanced Release of Beta Oxidation Products Due to Impaired Fatty Acid Oxidation

DEFF Research Database (Denmark)

Wensaas, Andreas J; Rustan, Arild C; Just, Marlene

2008-01-01

Objective: Increased availability of fatty acids is important for accumulation of intracellular lipids and development of insulin resistance in human myotubes. It is unknown whether different types of fatty acids like eicosapentaenoic acid (EPA) or tetradecylthioacetic acid (TTA) influence...... these processes. Research Design and Methods: We examined fatty acid and glucose metabolism, and gene expression in cultured human skeletal muscle cells from control and T2D individuals after four days preincubation with EPA or TTA. Results: T2D myotubes exhibited reduced formation of CO(2) from palmitic acid (PA....... EPA markedly enhanced TAG accumulation in myotubes, more pronounced in T2D cells. TAG accumulation and fatty acid oxidation were inversely correlated only after EPA preincubation, and total level of acyl-CoA was reduced. Glucose oxidation (CO(2) formation) was enhanced and lactate production decreased...

Phytanic acid alpha-oxidation: decarboxylation of 2-hydroxyphytanoyl-CoA to pristanic acid in human liver

NARCIS (Netherlands)

Verhoeven, N. M.; Wanders, R. J.; Schor, D. S.; Jansen, G. A.; Jakobs, C.

1997-01-01

The degradation of the first intermediate in the alpha-oxidation of phytanic acid, 2-hydroxyphytanoyl-CoA, was investigated. Human liver homogenates were incubated with 2-hydroxyphytanoyl-CoA or 2-hydroxyphytanic acid, after which formation of 2-ketophytanic acid and pristanic acid were studied.

Selenium dioxide catalysed oxidation of acetic acid hydrazide

Indian Academy of Sciences (India)

The mechanism of the reaction involves prior complex formation between the catalyst and substrate, hydrazide, followed by its oxidation by diprotonated bromate in a slow step. Acetic acid was found to be the oxidation product. Other kinetic data like effect of solvent polarity and ionic strength on the reaction support the ...

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.

Preparation, morphology and thermal properties of electrospun fatty acid eutectics/polyethylene terephthalate form-stable phase change ultrafine composite fibers for thermal energy storage

International Nuclear Information System (INIS)

Cai Yibing; Ke Huizhen; Lin Liang; Fei Xiuzhu; Wei Qufu; Song Lei; Hu Yuan; Fong Hao

2012-01-01

Highlights: ► Electrospun binary fatty acid eutectics/PET ultrafine composite fibers were prepared. ► Fatty acid eutectics had appropriate phase transition temperature and heat enthalpy. ► Their morphological structures and thermal properties were different from each other. ► Composite fibers could be innovative form-stable PCMs for thermal energy storage. - Abstract: The ultrafine composite fibers based on the composites of binary fatty acid eutectics and polyethylene terephthalate (PET) with varied fatty acid eutectics/PET mass ratios (50/100, 70/100, 100/100 and 120/100) were fabricated using the technique of electrospinning as form-stable phase change materials (PCMs). The five binary fatty acid eutectics including LA–MA, LA–PA, MA–PA, MA–SA and PA–SA were prepared according to Schrader equation, and then were selected as an innovative type of solid–liquid PCMs. The results characterized by differential scanning calorimeter (DSC) indicated that the prepared binary fatty acid eutectics with low phase transition temperatures and high heat enthalpies for climatic requirements were more suitable for applications in building energy storage. The structural morphologies, thermal energy storage and thermal stability properties of the ultrafine composite fibers were investigated by scanning electron microscope (SEM), DSC and thermogravimetric analysis (TGA), respectively. SEM images revealed that the electrospun binary fatty acid eutectics/PET ultrafine composite fibers possessed the wrinkled surfaces morphologies compared with the neat PET fibers with cylindrical shape and smooth surfaces; the grooves or ridges on the corrugated surface of the ultrafine composite fibers became more and more prominent with increasing fatty acid eutectics amount in the composite fibers. The fibers with the low mass ratio maintained good structural morphologies while the quality became worse when the mass ratio is too high (more than 100/100). DSC measurements

The Mechanical Properties of Recycled Polyethylene-Polyethylene Terephthalate Composites

Directory of Open Access Journals (Sweden)

Ehsan Avazverdi

2015-02-01

Full Text Available Polyethylene terephthalate (PET, one of the thermoplastic polymers, is encountered with arduous problems in its recycling. After recycling, its mechanical properties drop dramatically and therefore it cannot be used to produce the products as virgin PET does. Polyethylene is a thermoplastic polymer which can be easily recycled using the conventional recycling processes. The decreased mechanical properties of virgin polyethylene due to the environmental factors can be improved by reinforcing fillers. In this paper, we studied the effects of adding recycled polyethylene terephthalate (rPET as a filler, in various amounts with different sizes, on the physical and mechanical properties of recycled polyethylene. Composite samples were prepared using an internal mixer at temperature 185°C, well below rPET melting point (250°C, and characterized by their mechanical properties. To improve the compatibility between different components, PE grafted with maleic anhydride was added as a coupling agent in all the compositions under study. The mechanical properties of the prepared samples were performed using the tensile strength, impact strength, surface hardness and melt flow index (MFI tests. To check the dispersity of the polyethylene terephthalate powder in the polyethylene matrix, light microscopy was used. The results showed that the addition of rPET improved the tensile energy, tensile modulus and surface hardness of the composites while reduced the melt flow index, elongation-at-yield, tensile strength and fracture energy of impact test. We could conclude that with increasing rPET percentage in the recycled polyethylene matrix, the composite became brittle, in other words it decreased the plastic behavior of recycled polyethylene. Decreasing particle size led to higher surface contacts, increased the mechanical properties and made the composite more brittle. The light microscopy micrographs of the samples showed a good distribution of small r

Ferrous Iron Oxidation by Thiobacillus ferrooxidans: Inhibition with Benzoic Acid, Sorbic Acid, and Sodium Lauryl Sulfate

Science.gov (United States)

Onysko, Steven J.; Kleinmann, Robert L. P.; Erickson, Patricia M.

1984-01-01

Benzoic acid, sorbic acid, and sodium lauryl sulfate at low concentrations (5 to 10 mg/liter) each effectively inhibited bacterial oxidation of ferrous iron in batch cultures of Thiobacillus ferrooxidans. The rate of chemical oxidation of ferrous iron in low-pH, sterile batch reactors was not substantially affected at the tested concentrations (5 to 50 mg/liter) of any of the compounds. PMID:16346592

Studies of Tc oxidation states in humic acid solutions

International Nuclear Information System (INIS)

Wang Bo; Liu Dejun; Yao Jun

2011-01-01

The oxidation state of Tc is an important aspect of the speciation in groundwater which contained organic substances due to it control the precipitation, complexation, sorption and colloid formation behavior of the Tc under HWL geological disposal conditions. In present work, the oxidation states of Tc were investigated using the LaCl 3 coagulation method and solution extraction method in aqueous solutions in which the humic acid concentration range is from 0 to 20 mg/L and the Tc (VII) concentration is about 10 -8 mol/L. The radiocounting of 99 Tc was determined using liquid scintillation spectrometry. The humic acid will influence the radiocounting ratio of 99 Tc apparently, however, the quenching effect can be restrained once keep the volume of the cocktail to about twenty times of the sample volume. The LaCl 3 coagulation method was carried out for the investigation of Tc oxidation states in humic acid aqueous systems at about pH 8. The tetraphenylarsonium chloride (TPA)-chloroform extraction method was used also simultaneously to investigation the concentrations of Tc (IV) and Tc (VII) for the availability of the LaCl 3 precipitation method, and the experimental results demonstrate that tetravalent technetium and pertechnetate concentration are well agreement with the LaCl 3 precipitation method. These two experimental results demonstrated that Tc (VII) is very stable in the Tc (VII)-humic acid system during a 350 days experimental period, and the Tc (IV) concentrations are very lower, that is indicate that there didn't oxidizing reactions between the Fluka humic acid and Tc (VII) in aqueous solutions under anaerobic conditions. That means the presence of humic acids even in anaerobic groundwater is disadvantage for the retardance of radionuclides. (authors)

Electro-oxidation of methanol and formic acid on platinum nanoparticles with different oxidation levels

International Nuclear Information System (INIS)

Hsieh, Chien-Te; Hsiao, Han-Tsung; Tzou, Dong-Ying; Yu, Po-Yuan; Chen, Po-Yen; Jang, Bi-Sheng

2015-01-01

Herein reported is an atomic layer deposition (ALD) process of platinum (Pt) from (methylcyclopentadienyl) trimethylplatinum (MeCpPtMe 3 ) and oxygen (O 2 ) for synthesizing the Pt electrocatalysts toward methanol and formic acid oxidation. The as-synthesized Pt catalysts are thermally reduced in 5 vol% H 2 within temperature window of 150–450 °C. The reduction treatment induces a decrease in amount of Pt oxide (Pt–O) species, e.g., PtO and PtO 2 . The presence of Pt–O species not only enhances catalytic activity but also improves anti-poisoning ability toward the oxidation of methanol and formic acid. The improved activity originates from the fact that the Pt–O species, formed by the ALD route, creates a large number of active sites (e.g., Pt–O ads and Pt–(OH) ads ) to strip the CO-adsorbed sites, leading to a high-level of CO tolerance. This work also proposes a stepwise reaction steps to shed some lights on how the Pt–O species promote the catalytic activity. - Highlights: • This study adopts atomic layer deposition (ALD) to grow metallic Pt nanoparticles. • The Pt catalysts show catalytic activity toward methanol and formic acid oxidation. • The reduction treatment induces a decrease in amount of Pt oxide (Pt–O) species. • The Pt–O species creates a number of active sites to strip the CO-adsorbed sites. • A stepwise reaction step concerning the promoted catalytic activity is proposed

Simple quantification of surface carboxylic acids on chemically oxidized multi-walled carbon nanotubes

Science.gov (United States)

Gong, Hyejin; Kim, Seong-Taek; Lee, Jong Doo; Yim, Sanggyu

2013-02-01

The surface of multi-walled carbon nanotube (MWCNT) was chemically oxidized using nitric acid and sulfuric-nitric acid mixtures. Thermogravimetric analysis, transmission electron microscopy and infrared spectroscopy revealed that the use of acid mixtures led to higher degree of oxidation. More quantitative identification of surface carboxylic acids was carried out using X-ray photoelectron spectroscopy (XPS) and acid-base titration. However, these techniques are costly and require very long analysis times to promptly respond to the extent of the reaction. We propose a much simpler method using pH measurements and pre-determined pKa value in order to estimate the concentration of carboxylic acids on the oxidized MWCNT surfaces. The results from this technique were consistent with those obtained from XPS and titration, and it is expected that this simple quantification method can provide a cheap and fast way to monitor and control the oxidation reaction of MWCNT.

Photo-oxidation of gaseous ethanol on photocatalyst prepared by acid leaching of titanium oxide/hydroxyapatite composite

International Nuclear Information System (INIS)

Ono, Y.; Rachi, T.; Yokouchi, M.; Kamimoto, Y.; Nakajima, A.; Okada, K.

2013-01-01

Highlights: ► Photocatalyst powder was prepared by acid leaching of TiO 2 /apatite composite. ► The photocatalytic activity was evaluated from in situ FT-IR study using ethanol. ► Apatite in the composite had positive effect for the photo-oxidation of ethanol. ► The enhanced oxidation rate was explained by the difference in deactivation rate. - Abstract: Highly active photocatalysts were synthesized by leaching of heat-treated titanium dioxide (TiO 2 )/hydroxyapatite (HAp) powder with hydrochloric acid at 0.25, 0.50, 0.75 mol/l, and their photocatalytic activities were evaluated from in situ Fourier transform infrared (FT-IR) study of photo-oxidation of gaseous ethanol. By changing the acid concentration, the TiO 2 /HAp composite had different atomic ratios of Ca/Ti (0.0–2.8) and P/Ti (0.3–2.1). It was found that phosphate group remained on the surface of TiO 2 particle even in the sample treated with concentrated acid (0.75 mol/l). These acid-treated samples showed higher rates for ethanol photo-oxidation than the commercial TiO 2 powder, Degussa P25. The highest rate was obtained in the TiO 2 /HAp composite treated with the dilute (0.25 mol/l) acid in spite of its low content of TiO 2 photocatalyst. This enhanced photocatalytic activity was attributed to the result that the deactivation with repeated injections of ethanol gas was suppressed in the TiO 2 /HAp composites compared with the TiO 2 powders

The extraction of trace amounts of tantalum(V) from different mineral acid solutions by 4-(5-nonyl) pyridine oxide and trioctylamine oxide

International Nuclear Information System (INIS)

Ejaz, M.; Carswell, D.J.

1976-01-01

Data are presented on the distribution of trace amounts of tantalum(V) between different mineral acid solutions and 0.1M solutions of N-oxides of 4-(5-nonyl) pyridine and trioctylamine. The optimal acidity is 0.01-0.5M, depending on the nature of the acid. Common anions have little effect on extraction. Possible mechanism of extraction are suggested making use of slope analysis data. Separation factors for a number of metal ions with respect to tantalum are reported for the 0.1M 4-(5-nonyl)pyridine oxide - 1M sulphuric acid extraction system. Separation from uranium(VI), thorium(IV) and a number of fission products is suggested. The conclusions are unique as follows: Amine oxides are as unique as oxygen-donor extractants in their extraction of tantalum(V) from weakly acid solutions; tantalum is almost completely extracted from weakly nitric, hydrochloric and sulphuric acid solutions by both of the amine oxides; the extraction in low acidity solutions is independent of the nature of the anion of the acids present, indicating the ability of amine oxides to extract the product of hydrolysis of hydrolysable elements. In this respect amine oxides are much better than tributyl phosphate. (T.G.)

β-oxidation and rapid metabolism, but not uptake regulate brain eicosapentaenoic acid levels.

Science.gov (United States)

Chen, Chuck T; Bazinet, Richard P

2015-01-01

The brain has a unique polyunsaturated fatty acid composition, with high levels of arachidonic and docosahexaenoic acids (DHA) while levels of eicosapentaenoic acid (EPA) are several orders of magnitude lower. As evidence accumulated that fatty acid entry into the brain was not selective and, in fact, that DHA and EPA enter the brain at similar rates, new mechanisms were required to explain their large concentration differences in the brain. Here we summarize recent research demonstrating that EPA is rapidly and extensively β-oxidized upon entry into the brain. Although the ATP generated from the β-oxidation of EPA is low compared to the use of glucose, fatty acid β-oxidation may serve to regulate brain fatty acid levels in the absence of selective transportation. Furthermore, when β-oxidation of EPA is blocked, desaturation of EPA increases and Land׳s recycling decreases to maintain low EPA levels. Copyright © 2014 Elsevier Ltd. All rights reserved.

Protective effects of gallic acid against spinal cord injury-induced oxidative stress.

Science.gov (United States)

Yang, Yong Hong; Wang, Zao; Zheng, Jie; Wang, Ran

2015-08-01

The present study aimed to investigate the role of gallic acid in oxidative stress induced during spinal cord injury (SCI). In order to measure oxidative stress, the levels of lipid peroxide, protein carbonyl, reactive oxygen species and nitrates/nitrites were determined. In addition, the antioxidant status during SCI injury and the protective role of gallic acid were investigated by determining glutathione levels as well as the activities of catalase, superoxide dismutase, glutathione peroxidase and glutathione-S-transferase. Adenosine triphophatase (ATPase) enzyme activities were determined to evaluate the role of gallic acid in SCI-induced deregulation of the activity of enzymes involved in ion homeostasis. The levels of inflammatory markers such as nuclear factor (NF)-κB and cycloxygenase (COX)-2 were determined by western blot analysis. Treatment with gallic acid was observed to significantly mitigate SCI-induced oxidative stress and the inflammatory response by reducing the oxidative stress, decreasing the expression of NF-κB and COX-2 as well as increasing the antioxidant status of cells. In addition, gallic acid modulated the activity of ATPase enzymes. Thus the present study indicated that gallic acid may have a role as a potent antioxidant and anti-inflammatory agent against SCI.

Electro-oxidation of methanol and formic acid on platinum nanoparticles with different oxidation levels

Energy Technology Data Exchange (ETDEWEB)

Hsieh, Chien-Te, E-mail: cthsieh@saturn.yzu.edu.tw [Department of Chemical Engineering and Materials Science, Yuan Ze University, Taoyuan 320, Taiwan (China); Hsiao, Han-Tsung; Tzou, Dong-Ying; Yu, Po-Yuan [Department of Chemical Engineering and Materials Science, Yuan Ze University, Taoyuan 320, Taiwan (China); Chen, Po-Yen; Jang, Bi-Sheng [Materials and Electro-Optics Research Division, National Chung-Shan Institute of Science and Technology, Taoyuan 325, Taiwan (China)

2015-01-15

Herein reported is an atomic layer deposition (ALD) process of platinum (Pt) from (methylcyclopentadienyl) trimethylplatinum (MeCpPtMe{sub 3}) and oxygen (O{sub 2}) for synthesizing the Pt electrocatalysts toward methanol and formic acid oxidation. The as-synthesized Pt catalysts are thermally reduced in 5 vol% H{sub 2} within temperature window of 150–450 °C. The reduction treatment induces a decrease in amount of Pt oxide (Pt–O) species, e.g., PtO and PtO{sub 2}. The presence of Pt–O species not only enhances catalytic activity but also improves anti-poisoning ability toward the oxidation of methanol and formic acid. The improved activity originates from the fact that the Pt–O species, formed by the ALD route, creates a large number of active sites (e.g., Pt–O{sub ads} and Pt–(OH){sub ads}) to strip the CO-adsorbed sites, leading to a high-level of CO tolerance. This work also proposes a stepwise reaction steps to shed some lights on how the Pt–O species promote the catalytic activity. - Highlights: • This study adopts atomic layer deposition (ALD) to grow metallic Pt nanoparticles. • The Pt catalysts show catalytic activity toward methanol and formic acid oxidation. • The reduction treatment induces a decrease in amount of Pt oxide (Pt–O) species. • The Pt–O species creates a number of active sites to strip the CO-adsorbed sites. • A stepwise reaction step concerning the promoted catalytic activity is proposed.

Aerosol Fragmentation Driven by Coupling of Acid-Base and Free-Radical Chemistry in the Heterogeneous Oxidation of Aqueous Citric Acid by OH Radicals.

Science.gov (United States)

Liu, Matthew J; Wiegel, Aaron A; Wilson, Kevin R; Houle, Frances A

2017-08-10

A key uncertainty in the heterogeneous oxidation of carboxylic acids by hydroxyl radicals (OH) in aqueous-phase aerosol is how the free-radical reaction pathways might be altered by acid-base chemistry. In particular, if acid-base reactions occur concurrently with acyloxy radical formation and unimolecular decomposition of alkoxy radicals, there is a possibility that differences in reaction pathways impact the partitioning of organic carbon between the gas and aqueous phases. To examine these questions, a kinetic model is developed for the OH-initiated oxidation of citric acid aerosol at high relative humidity. The reaction scheme, containing both free-radical and acid-base elementary reaction steps with physically validated rate coefficients, accurately predicts the experimentally observed molecular composition, particle size, and average elemental composition of the aerosol upon oxidation. The difference between the two reaction channels centers on the reactivity of carboxylic acid groups. Free-radical reactions mainly add functional groups to the carbon skeleton of neutral citric acid, because carboxylic acid moieties deactivate the unimolecular fragmentation of alkoxy radicals. In contrast, the conjugate carboxylate groups originating from acid-base equilibria activate both acyloxy radical formation and carbon-carbon bond scission of alkoxy radicals, leading to the formation of low molecular weight, highly oxidized products such as oxalic and mesoxalic acid. Subsequent hydration of carbonyl groups in the oxidized products increases the aerosol hygroscopicity and accelerates the substantial water uptake and volume growth that accompany oxidation. These results frame the oxidative lifecycle of atmospheric aerosol: it is governed by feedbacks between reactions that first increase the particle oxidation state, then eventually promote water uptake and acid-base chemistry. When coupled to free-radical reactions, acid-base channels lead to formation of low molecular

Photo-oxidation of gaseous ethanol on photocatalyst prepared by acid leaching of titanium oxide/hydroxyapatite composite

Energy Technology Data Exchange (ETDEWEB)

Ono, Y., E-mail: ono-y@kanagawa-iri.go.jp [Mechanical and Material Engineering Division, Kanagawa Industrial Technology Center, Ebina, Kanagawa 243-0435 (Japan); Rachi, T.; Yokouchi, M.; Kamimoto, Y. [Mechanical and Material Engineering Division, Kanagawa Industrial Technology Center, Ebina, Kanagawa 243-0435 (Japan); Nakajima, A. [Department of Metallurgy and Ceramics Science, Tokyo Institute of Technology, Meguro, Tokyo 152-8552 (Japan); Okada, K. [Materials and Structures Laboratory, Tokyo Institute of Technology, Midori, Yokohama, Kanagawa 226-8503 (Japan)

2013-06-01

Highlights: ► Photocatalyst powder was prepared by acid leaching of TiO{sub 2}/apatite composite. ► The photocatalytic activity was evaluated from in situ FT-IR study using ethanol. ► Apatite in the composite had positive effect for the photo-oxidation of ethanol. ► The enhanced oxidation rate was explained by the difference in deactivation rate. - Abstract: Highly active photocatalysts were synthesized by leaching of heat-treated titanium dioxide (TiO{sub 2})/hydroxyapatite (HAp) powder with hydrochloric acid at 0.25, 0.50, 0.75 mol/l, and their photocatalytic activities were evaluated from in situ Fourier transform infrared (FT-IR) study of photo-oxidation of gaseous ethanol. By changing the acid concentration, the TiO{sub 2}/HAp composite had different atomic ratios of Ca/Ti (0.0–2.8) and P/Ti (0.3–2.1). It was found that phosphate group remained on the surface of TiO{sub 2} particle even in the sample treated with concentrated acid (0.75 mol/l). These acid-treated samples showed higher rates for ethanol photo-oxidation than the commercial TiO{sub 2} powder, Degussa P25. The highest rate was obtained in the TiO{sub 2}/HAp composite treated with the dilute (0.25 mol/l) acid in spite of its low content of TiO{sub 2} photocatalyst. This enhanced photocatalytic activity was attributed to the result that the deactivation with repeated injections of ethanol gas was suppressed in the TiO{sub 2}/HAp composites compared with the TiO{sub 2} powders.

Electrochemical oxidation of methanol and formic acid in fuel cell processes

Energy Technology Data Exchange (ETDEWEB)

Seland, Frode

2005-07-01

The main objectives of the thesis work were: (1), to study the oxidation of methanol and formic acid on platinum electrodes by employing conventional and advanced electrochemical methods, and (2), to develop membrane electrode assemblies based on polybenzimidazole membranes that can be used in fuel cells up to 200 C. D.c. voltammetry and a.c. voltammetry studies of methanol and formic acid on polycrystalline platinum in sulphuric acid electrolyte were performed to determine the mechanism and kinetics of the oxidation reactions. A combined potential step and fast cyclic voltammetry experiment was employed to investigate the time dependence primarily of methanol oxidation on platinum. Charge measurements clearly demonstrated the existence of a parallel path at low potentials and short times without formation of adsorbed CO. Furthermore, experimental results showed that only the serial path, via adsorbed CO, exists during continuous cycling, with the first step being diffusion controlled dissociative adsorption of methanol directly from the bulk electrolyte. The saturation charge of adsorbed CO derived from methanol was found to be significantly lower than CO derived from formic acid or dissolved CO. This was attributed to the site requirements of the dehydrogenation steps, and possibly different compositions of linear, bridged or multiply bonded CO. The coverage of adsorbed CO from formic acid decreased significantly at potentials just outside of the hydrogen region (0.35 V vs. RHE), while it did not start to decrease significantly until about 0.6 V vs. RHE for methanol. Adsorbed CO from dissolved CO rapidly oxidized at potentials above about 0.75 V due to formation of platinum oxide. Data from a.c. voltammograms from 0.5 Hz up to 30 kHz were assembled into electrochemical impedance spectra (EIS) and analyzed using equivalent circuits. The main advantages of collecting EIS spectra from a.c. voltammetry experiments are the ability to directly correlate the impedance

Mechanistic studies of formic acid oxidation at polycarbazole supported Pt nanoparticles

International Nuclear Information System (INIS)

Moghaddam, Reza B.; Pickup, Peter G.

2013-01-01

Highlights: •A polycarbazole support decreases the accumulation of adsorbed intermediates on Pt during formic acid oxidation. •Polycarbazole causes a bilayer of Cu to form on Pt nanoparticles during Cu underpotential deposition. •XPS suggests that both of these effects are due to electron donation from the metal (Pt or Cu) into the polymer π-system. -- Abstract: Mechanistic aspects of the promotion of formic acid oxidation at Pt nanoparticles supported on a thin layer of polycarbazole (PCZ) have been investigated by voltammetry and X-ray photoelectron spectroscopy (XPS). The Pt nanoparticles were drop coated onto a glassy carbon (GC) electrode coated with a ca. 9 nm layer of electrochemically deposited polycarbazole. After 500 s of formic acid oxidation at 0 V vs. SCE, the current at a GC/PCZ/Pt electrode was 25 times higher than at a GC/Pt electrode. Voltammetry in formic acid free H 2 SO 4 following potentiostatic oxidation of formic acid revealed that there was less accumulation of adsorbed intermediates for the polycarbazole supported Pt nanoparticles than for those deposited directly onto the glassy carbon with, 50% more Pt sites remaining available for the GC/PCZ/Pt electrode relative to the GC/Pt electrode. Independent CO stripping experiments revealed only slight differences, while Cu underpotential deposition surprisingly resulted in the deposition of a ca. two-fold excess of Cu on the polycarbazole supported particles. This observation was supported by XPS which also revealed a second Cu signal at a higher binding energy, suggesting electron donation into the conjugated π system of the polymer. Such an interaction of Pt with the polycarbazole may be responsible for its higher activity for formic acid oxidation

The effect of valinomycin in fibroblasts from patients with fatty acid oxidation disorders

International Nuclear Information System (INIS)

Ndukwe Erlingsson, Uzochi Chimdinma; Iacobazzi, Francesco; Liu, Aiping; Ardon, Orly; Pasquali, Marzia; Longo, Nicola

2013-01-01

Highlights: •Valinomycin can cause mitochondrial stress and stimulate fatty acid oxidation. •Cells with VLCAD deficiency fail to increase fatty acid oxidation in response to valinomycin. •Response to valinomycin can help in the diagnosis of VLCAD deficiency. -- Abstract: Disorders of the carnitine cycle and of the beta oxidation spiral impair the ability to obtain energy from fats at time of fasting and stress. This can result in hypoketotic hypoglycemia, cardiomyopathy, cardiac arrhythmia and other chronic medical problems. The in vitro study of fibroblasts from patients with these conditions is impaired by their limited oxidative capacity. Here we evaluate the capacity of valinomycin, a potassium ionophore that increases mitochondrial respiration, to increase the oxidation of fatty acids in cells from patients with inherited fatty acid oxidation defects. The addition of valinomycin to fibroblasts decreased the accumulation of the lipophilic cation tetraphenylphosphonium (TPP + ) at low concentrations due to the dissipation of the mitochondrial membrane potential. At higher doses, valinomycin increased TPP + accumulation due to the increased potassium permeability of the plasma membrane and subsequent cellular hyperpolarization. The incubation of normal fibroblasts with valinomycin increased [ 14 C]-palmitate oxidation (measured as [ 14 C]O 2 release) in a dose-dependent manner. By contrast, valinomycin failed to increase palmitate oxidation in fibroblasts from patients with very long chain acyl CoA dehydrogenase (VLCAD) deficiency. This was not observed in fibroblasts from patients heterozygous for this condition. These results indicate that valinomycin can increase fatty acid oxidation in normal fibroblasts and could be useful to differentiate heterozygotes from patients affected with VLCAD deficiency

'Low-acid' sulfide oxidation using nitrate-enriched groundwater

Science.gov (United States)

Donn, Michael; Boxall, Naomi; Reid, Nathan; Meakin, Rebecca; Gray, David; Kaksonen, Anna; Robson, Thomas; Shiers, Denis

2016-04-01

Acid drainage (AMD/ARD) is undoubtedly one of the largest environmental, legislative and economic challenges facing the mining industry. In Australia alone, at least 60m is spent on AMD related issues annually, and the global cost is estimated to be in the order of tens of billions US. Furthermore, the challenge of safely and economically storing or treating sulfidic wastes will likely intensify because of the trend towards larger mines that process increasingly higher volumes of lower grade ores and the associated sulfidic wastes and lower profit margins. While the challenge of managing potentially acid forming (PAF) wastes will likely intensify, the industrial approaches to preventing acid production or ameliorating the effects has stagnated for decades. Conventionally, PAF waste is segregated and encapsulated in non-PAF tips to limit access to atmospheric oxygen. Two key limitations of the 'cap and cover' approach are: 1) the hazard (PAF) is not actually removed; only the pollutant linkage is severed; and, 2) these engineered structures are susceptible to physical failure in short-to-medium term, potentially re-establishing that pollutant linkage. In an effort to address these concerns, CSIRO is investigating a passive, 'low-acid' oxidation mechanism for sulfide treatment, which can potentially produce one quarter as much acidity compared with pyrite oxidation under atmospheric oxygen. This 'low-acid' mechanism relies on nitrate, rather than oxygen, as the primary electron accepter and the activity of specifically cultured chemolithoautotrophic bacteria and archaea communities. This research was prompted by the observation that, in deeply weathered terrains of Australia, shallow (oxic to sub-oxic) groundwater contacting weathering sulfides are commonly inconsistent with the geochemical conditions produced by ARD. One key characteristic of these aquifers is the natural abundance of nitrate on a regional scale, which becomes depleted around the sulfide bodies, and

Molar mass of poly(ethylene terephthalate) (PET) during ultimate uniaxial drawing

NARCIS (Netherlands)

Göschel, U.; Cools, P.J.C.H.

2000-01-01

The changes of the average molar mass Mw, Mn, Mz, and molar mass distributions during multistep uniaxial drawing of poly(ethylene terephthalate) (PET) to achieve ultimate mechanical properties have been studied in detail by means of size exclusion chromatography (SEC) with triple detection:

Molar-Mass of Poly(Ethylene-Terephthalate) (PET) During Ultimate Uniaxial Drawing

NARCIS (Netherlands)

Göschel, A.G.P.U.; Cools, P.J.C.H.

2000-01-01

The changes of the average molar mass Mw, Mn, Mz, and molar mass distributions during multistep uniaxial drawing of poly(ethylene terephthalate) (PET) to achieve ultimate mechanical properties have been studied in detail by means of size exclusion chromatography (SEC) with triple detection:

Kinetic Studies on the Oxidation of Some para and meta-Substituted Cinnamic Acids by Pyridinium Bromochromate in the Presence of Oxalic Acid (A Co-oxidation Study

Directory of Open Access Journals (Sweden)

G. Vanangamudi

2009-01-01

Full Text Available The kinetics of oxidation of cinnamic acids by pyridinium bromochromate (PBC in the presence of oxalic acid has been studied in acetic acid-water (60:40% medium. The reaction shows unit order dependence each with respect to oxidant as well as oxalic acid [OX], the order with respect to [H+] and [CA] are fractional. The reaction is acid catalyzed and a low dielectric constant favours the reaction. Increase the ionic strength has no effect on the reaction rate. In the case of substituted cinnamic acids the order with respect to substrate vary depending upon the nature of the substituent present in the ring. In general, the electron withdrawing substituents retard the rate while the electron releasing substituents enhance the rate of reaction. From the kinetic data obtained the activation parameters have been computed and a suitable mechanism has been proposed.

Study on the synthesis of dimethyl 1,4-cyclohexanedicarboxylate by catalytic hydrogenation of dimethyl terephthalate

Directory of Open Access Journals (Sweden)

LI Yuanhua

2016-12-01

Full Text Available In the field of polymer industry,1,4-cyclohexanedimethanol (CHDM occupies an important position especially for the synthesis of highly valued polyester products.In industry,CHDM is prepared from dimethyl terephthalate (DMT through a two-step hydrogenation process Palladium supported on magnesium oxide (Pd/MgO was prepared by animpregnation method and was characterized by x-ray diffraction (XRD,transmission electron microscope (TEM and scan electron microscope (SEM.During the hydrogenation of DMT to synthesize dimethyl 1,4-cyclohexanedicarboxylate (DMCD,the as-prepared Pd/MgO was used as the catalyst with methyl acetate as the solvent.Under optimized reaction conditions (reaction temperature:180 ℃,reaction pressure:4.5 MPa,the conversion of DMT was 100% and the selectivity of DMCD was 99%.Such a catalyst shows a good potential in industrial applications.

Orphan drugs in development for long-chain fatty acid oxidation disorders: challenges and progress

OpenAIRE

Merritt II, J Lawrence; Sun,Angela

2015-01-01

Angela Sun, J Lawrence Merritt II Department of Pediatrics, University of Washington, Seattle, WA, USA Abstract: Fatty acid oxidation disorders are inborn errors of metabolism resulting in failure of ß-oxidation within or transport of fatty acids into the mitochondria. The long-chain fatty acid oxidation disorders are characterized by variable presentations ranging from newborn cardiomyopathy, to infantile hypoketotic hypoglycemia resulting from liver involvement, to skeletal myopa...

Formation of iron oxides from acid mine drainage and magnetic separation of the heavy metals adsorbed iron oxides

Energy Technology Data Exchange (ETDEWEB)

Kwon, Hee Won; Kim, Jeong Jin; Kim, Young Hun [Andong National University, Andong (Korea, Republic of); Ha, Dong Woo [Korea Electrotechnology Research Institute, Changwon (Korea, Republic of)

2016-03-15

There are a few thousand abandoned metal mines in South Korea. The abandoned mines cause several environmental problems including releasing acid mine drainage (AMD), which contain a very high acidity and heavy metal ions such as Fe, Cu, Cd, Pb, and As. Iron oxides can be formed from the AMD by increasing the solution pH and inducing precipitation. Current study focused on the formation of iron oxide in an AMD and used the oxide for adsorption of heavy metals. The heavy metal adsorbed iron oxide was separated with a superconducting magnet. The duration of iron oxide formation affected on the type of mineral and the degree of magnetization. The removal rate of heavy metal by the adsorption process with the formed iron oxide was highly dependent on the type of iron oxide and the solution pH. A high gradient magnetic separation (HGMS) system successfully separated the iron oxide and harmful heavy metals.

Effects of hypoxia and pyruvate infusion on myocardial fatty acid oxidation measured with 123I heptadecanoic acid

International Nuclear Information System (INIS)

Comans, E.F.I.; Visser, F.C.; Elzinga, Gijs

1993-01-01

Radio-iodinated fatty acids like 123 I heptadecanoic acid (HDA) can be used for the non-invasive delineation of myocardial non-esterified fatty acid (FA) metabolism. In this study the quantitative value of HDA was assessed for the measurement of myocardial FA oxidation. In an isolated saline perfused rat heart preparation myocardial time-activity curves were made during control perfusion and after inhibition of FA oxidation by hypoxia and infusion of 10.0 mM pyruvate, respectively. Control experiments were performed using 1- 14 C palmitate as the 'golden standard' for myocardial FA oxidation. Myocardial HDA oxidation was calculated from the amplitude of the third exponential term of the time-activity curve. During control perfusion no differences were observed between the calculated oxygen equivalents (from HDA oxidation) and the measured (A-V oxygen content difference) and the estimated ( 14 CO 2 production) values. Inhibition of palmitate oxidation with pyruvate was accurately detected with HDA. During hypoxic perfusion, an overestimation of palmitate oxidation was calculated on the basic of HDA oxidation. Infusion of pyruvate did not influence the time constants of the time-activity curves, whereas during hypoxic perfusion an increase of the time constant of the third exponential term was observed, probably caused by the presence of back-diffusion of non-metabolized HDA. We conclude that HDA can be used as a quantitative tool for the measurement of myocardial FA oxidation under various metabolic conditions. During periods of a decreased oxygen availability back-diffusion of FA needs to be taken into account for the interpretation of the myocardial time-activity curves. (author)

Oxidation of indole-3-acetic acid to oxindole-3-acetic acid by an enzyme preparation from Zea mays

Science.gov (United States)

Reinecke, D. M.; Bandurski, R. S.

1988-01-01

Indole-3-acetic acid is oxidized to oxindole-3-acetic acid by Zea mays tissue extracts. Shoot, root, and endosperm tissues have enzyme activities of 1 to 10 picomoles per hour per milligram protein. The enzyme is heat labile, is soluble, and requires oxygen for activity. Cofactors of mixed function oxygenase, peroxidase, and intermolecular dioxygenase are not stimulatory to enzymic activity. A heat-stable, detergent-extractable component from corn enhances enzyme activity 6- to 10-fold. This is the first demonstration of the in vitro enzymic oxidation of indole-3-acetic acid to oxindole-3-acetic acid in higher plants.

Hepatic fatty acid oxidation : activity, localization and function of some enzymes involved

NARCIS (Netherlands)

A. van Tol (Arie)

1971-01-01

textabstractFatty acid oxidation is an important pathway for energy production in mammals and birds. In animal tissues the enzymes of fatty acid oxidation are located in the mitochondrion. Recent reports suggest that this is not the case in Castor bean endosperm. In this tissue the enzymes of

The acidic properties of mixed tin and antimony oxide catalysts

Energy Technology Data Exchange (ETDEWEB)

Irving, E.A.; Taylor, D.

1978-01-01

The acidic properties of mixed tin + antimony oxide catalysts were studied in the isomerization of 3,3-dimethyl-1-butene, cyclopropane, 1-butene, and cis-2-butene and the dehydration of isopropanol over the mixed oxides outgassed at room temperature and 698/sup 0/K. Only the zero-order portions of the reaction were used for calculations. With catalysts outgassed at room temperature, weakly acidic sites were present, and all the reactions probably occurred by a carbonium ion mechanism with Broensted acid sites as a source of protons. The rates increased with increasing antimony content to a maximum at approx. 50 at. % and then decreased with further increase in the antimony content. Outgassing of the catalysts at 698/sup 0/K increased the isomerization rate of 3,3-dimethyl-1-butene, but decreased those for cyclopropane and isopropanol due to poisoning by the propylene produced. For 1-butene and cis-2-butene and catalysts outgassed at 698/sup 0/K, only catalysts with less than 50Vertical Bar3< antimony were active. The catalysts were poisoned by treatment with bases or with sodium acetate. A proposed correlation between rates and acidity led to the conclusion that the catalyst composition corresponding to maximum acidity differs from that for maximum selective oxidation activity. Graphs and 10 references.

A spectroelectrochemical and chemical study on oxidation of hydroxycinnamic acids in aprotic medium

Energy Technology Data Exchange (ETDEWEB)

Petrucci, Rita [Dipartimento di Ingegneria Chimica M.M.P.M., Universita di Roma ' La Sapienza' , via del Castro Laurenziano 7, I-00161 Rome (Italy)]. E-mail: rita.petrucci@uniroma1.it; Astolfi, Paola [Dipartimento di Scienze dei Materiali e della Terra, Universita Politecnica delle Marche, via Brecce Bianche, I-60131 Ancona (Italy); Greci, Lucedio [Dipartimento di Scienze dei Materiali e della Terra, Universita Politecnica delle Marche, via Brecce Bianche, I-60131 Ancona (Italy); Firuzi, Omidreza [Dipartimento di Farmacologia delle Sostanze Naturali e Fisiologia Generale, Universita di Roma ' La Sapienza' , p.le Aldo Moro 5, I-00185 Rome (Italy); Saso, Luciano [Dipartimento di Farmacologia delle Sostanze Naturali e Fisiologia Generale, Universita di Roma ' La Sapienza' , p.le Aldo Moro 5, I-00185 Rome (Italy); Marrosu, Giancarlo [Dipartimento di Ingegneria Chimica M.M.P.M., Universita di Roma ' La Sapienza' , via del Castro Laurenziano 7, I-00161 Rome (Italy)

2007-02-01

Electrochemical and chemical oxidation of hydroxycinnamic acids (HCAs) was studied to investigate the mechanisms occurring in their antioxidant activities in a protons poor medium. Electrolyses and chemical reactions were followed on-line by monitoring the UV-spectral changes with time; final solutions were analysed by HPLC-MS. Anodic oxidation of mono- and di-HCAs, studied by cyclic voltammetry and controlled potential electrolyses, occurs via a reversible one-step two-electrons process, yielding the corresponding stable phenoxonium cation. A cyclization product was also proposed, as supported by ESR studies. Chemical oxidation with lead dioxide leads to different oxidation products according to the starting substrate. Di-HCAs like chlorogenic and rosmarinic acids and the ethyl ester of caffeic acid gave the corresponding neutral o-quinones, while mono-HCAs like cumaric, ferulic and sinapinic acids yielded the corresponding unstable neutral phenoxyl radical, as supported by the formation of dimerization products evidenced by HPLC-MS. In the case of caffeic acid, traces of the dimerization product suggest that the neutral phenoxyl radical may competitively undergo dimerization or decomposition of the neutral quinone. Chemical oxidation of HCAs was also followed by ESR spectroscopy: the di-HCAs radical anions were generated and detected, whereas among the mono-HCAs only the phenoxyl radical of the sinapinic acid was recorded.

PREPARATION OF METAL OXIDE POWDERS FROM METAL LOADED VERSATIC ACID

OpenAIRE

KAKIHATA, Takayuki; USAMI, Kensuke; YAMAMOTO, Hideki; SHIBATA, Junji

1998-01-01

A production process for metal oxide powders was developed using a solvent extraction method. Versatic Acid 10 and D2EHPA solutions containing copper, zinc and nickel were used for a precipitation-stripping process, where oxalic acid was added to the solution as a precipitation reagent.Copper, zinc and nickel oxalates were easily formed in an aqueous phase, and 99.9% of precipitation was obtained for each metal during this process. These metal oxalates were easily converted to metal oxides by...

Fatty Acid Oxidation and Cardiovascular Risk during Menopause: A Mitochondrial Connection?

Directory of Open Access Journals (Sweden)

Paulo J. Oliveira

2012-01-01

Full Text Available Menopause is a consequence of the normal aging process in women. This fact implies that the physiological and biochemical alterations resulting from menopause often blur with those from the aging process. It is thought that menopause in women presents a higher risk for cardiovascular disease although the precise mechanism is still under discussion. The postmenopause lipid profile is clearly altered, which can present a risk factor for cardiovascular disease. Due to the role of mitochondria in fatty acid oxidation, alterations of the lipid profile in the menopausal women will also influence mitochondrial fatty acid oxidation fluxes in several organs. In this paper, we propose that alterations of mitochondrial bioenergetics in the heart, consequence from normal aging and/or from the menopausal process, result in decreased fatty acid oxidation and accumulation of fatty acid intermediates in the cardiomyocyte cytosol, resulting in lipotoxicity and increasing the cardiovascular risk in the menopausal women.

Oxidative kinetics of amino acids by peroxydisulfate: Effect of dielectric constant

International Nuclear Information System (INIS)

Khalid, Mohammad A. A.

2008-01-01

The kinetics and mechanism of oxidation of alanine, asparagines, cysteine, glutamic acid, lysine, phenylalanine and serine by peroxydisulfate ion have been studied in aqueous acidic (sulfuric acid) medium at the temperature range 60-80C. The rate shows first order dependence on peroxydisulfate concentration and zero order dependence on amino acid concentration. The rate law observed is: -d [S2O82-] /dt = Kobs [S2O82-] [amino acid]0. An autocatalytic effect has been observed in amino acids oxidation due to formation of Schiff's base between the formed aldehyde and parent amino acid. A decrease in the dielectric constant of the medium-adding acetic acid (5-15% v/v) results in a decrease in the rate in all cases studied. Reactions were carried out at different temperature (60-80C) and the thermodynamics parameters have been calculated. The logarithm of the rate constant is linearly interrelated to the square root of the ionic strength. (author)

Colorimetric study of oxidation kinetics of thiolactic acid (2 - mercaptopropionic acid) by hexacyanoferrate (III) in acid and alkaline media

International Nuclear Information System (INIS)

Kachhwaha, O.P.; Potter, P.C.; Kapoor, R.C.

1985-01-01

The oxidation kinetics of thiolactic acid by hexacyanoferrate (III) in acid and alkaline media employing the calorimetric method have been described. The two compounds react in equimolar ratio in both media, but the kinetic results are different in both media. In acid medium the total order is three, two with respect to thiol and one in oxidant. The rate of the reaction shows an inverse proportionality to (H + ) and also varies inversely with decreasing dielectric constant of the medium. In alkaline medium, the total order of the reaction is two, being unity in each reactant. The rate increases with increased pH value. Additions of ferrocyanide and dithio dilactic acid have no effect on the rate in both media. Additions of a neutral electrolyte does not affect the rate in the acid medium, while a positive salt effect was observed in an alkaline medium. Activation parameters have been evaluated in both media and in a medium of low dialectric. Different reaction schemes have been proposed for acid and alkaline media and have satisfactory explained the experimental data, except for the pH rate. (author)

The effect of valinomycin in fibroblasts from patients with fatty acid oxidation disorders

Energy Technology Data Exchange (ETDEWEB)

Ndukwe Erlingsson, Uzochi Chimdinma [Division of Medical Genetics, Department of Pediatrics, University of Utah, 2C412 SOM, 50 North Mario Capecchi Drive, Salt Lake City, UT 84132 (United States); Iacobazzi, Francesco [Division of Medical Genetics, Department of Pediatrics, University of Utah, 2C412 SOM, 50 North Mario Capecchi Drive, Salt Lake City, UT 84132 (United States); Department of Basic Medical Sciences, University of Bari, Piazza Giulio Cesare 11, Policlinico, I-70124 Bari (Italy); Liu, Aiping [ARUP Institute for Clinical and Experimental Pathology, ARUP Laboratories, 500 Chipeta Way, Salt Lake City, UT 84108 (United States); Ardon, Orly; Pasquali, Marzia [Division of Medical Genetics, Department of Pediatrics, University of Utah, 2C412 SOM, 50 North Mario Capecchi Drive, Salt Lake City, UT 84132 (United States); ARUP Institute for Clinical and Experimental Pathology, ARUP Laboratories, 500 Chipeta Way, Salt Lake City, UT 84108 (United States); Department of Pathology, University of Utah, Salt Lake City, UT 84132 (United States); Longo, Nicola, E-mail: Nicola.Longo@hsc.utah.edu [Division of Medical Genetics, Department of Pediatrics, University of Utah, 2C412 SOM, 50 North Mario Capecchi Drive, Salt Lake City, UT 84132 (United States); ARUP Institute for Clinical and Experimental Pathology, ARUP Laboratories, 500 Chipeta Way, Salt Lake City, UT 84108 (United States); Department of Pathology, University of Utah, Salt Lake City, UT 84132 (United States)

2013-08-09

Highlights: •Valinomycin can cause mitochondrial stress and stimulate fatty acid oxidation. •Cells with VLCAD deficiency fail to increase fatty acid oxidation in response to valinomycin. •Response to valinomycin can help in the diagnosis of VLCAD deficiency. -- Abstract: Disorders of the carnitine cycle and of the beta oxidation spiral impair the ability to obtain energy from fats at time of fasting and stress. This can result in hypoketotic hypoglycemia, cardiomyopathy, cardiac arrhythmia and other chronic medical problems. The in vitro study of fibroblasts from patients with these conditions is impaired by their limited oxidative capacity. Here we evaluate the capacity of valinomycin, a potassium ionophore that increases mitochondrial respiration, to increase the oxidation of fatty acids in cells from patients with inherited fatty acid oxidation defects. The addition of valinomycin to fibroblasts decreased the accumulation of the lipophilic cation tetraphenylphosphonium (TPP{sup +}) at low concentrations due to the dissipation of the mitochondrial membrane potential. At higher doses, valinomycin increased TPP{sup +} accumulation due to the increased potassium permeability of the plasma membrane and subsequent cellular hyperpolarization. The incubation of normal fibroblasts with valinomycin increased [{sup 14}C]-palmitate oxidation (measured as [{sup 14}C]O{sub 2} release) in a dose-dependent manner. By contrast, valinomycin failed to increase palmitate oxidation in fibroblasts from patients with very long chain acyl CoA dehydrogenase (VLCAD) deficiency. This was not observed in fibroblasts from patients heterozygous for this condition. These results indicate that valinomycin can increase fatty acid oxidation in normal fibroblasts and could be useful to differentiate heterozygotes from patients affected with VLCAD deficiency.

Epoxy Stearic Acid, an Oxidative Product Derived from Oleic Acid, Induces Cytotoxicity, Oxidative Stress, and Apoptosis in HepG2 Cells.

Science.gov (United States)

Liu, Ying; Cheng, Yajun; Li, Jinwei; Wang, Yuanpeng; Liu, Yuanfa

2018-05-23

In the present study, effects of cis-9,10-epoxy stearic acid (ESA) generated by the thermal oxidation of oleic acid on HepG2 cells, including cytotoxicity, apoptosis, and oxidative stress, were investigated. Our results revealed that ESA decreased the cell viability and induced cell death. Cell cycle analysis with propidium iodide staining showed that ESA induced cell cycle arrest at the G0/G1 phase in HepG2 cells. Cell apoptosis analysis with annexin V and propidium iodide staining demonstrated that ESA induced HepG2 cell apoptotic events in a dose- and time-dependent manner; the apoptosis of cells after treated with 500 μM ESA for 12, 24, and 48 h was 32.16, 38.70, and 65.80%, respectively. Furthermore, ESA treatment to HepG2 cells resulted in an increase in reactive oxygen species and malondialdehyde (from 0.84 ± 0.02 to 8.90 ± 0.50 nmol/mg of protein) levels and a reduction in antioxidant enzyme activity, including superoxide dismutase (from 1.34 ± 0.27 to 0.10 ± 0.007 units/mg of protein), catalase (from 100.04 ± 5.05 to 20.09 ± 3.00 units/mg of protein), and glutathione peroxidase (from 120.44 ± 7.62 to 35.84 ± 5.99 milliunits/mg of protein). These findings provide critical information on the effects of ESA on HepG2 cells, particularly cytotoxicity and oxidative stress, which is important for the evaluation of the biosafety of the oxidative product of oleic acid.

Assessment of myocardial metabolism with iodine-123 heptadecanoic acid: effect of decreased fatty acid oxidation on deiodination

International Nuclear Information System (INIS)

Luethy, P.C.; Chatelain, P.; Papageorgiou, I.; Schubiger, A.; Lerch, R.A.

1988-01-01

Terminally radioiodinated fatty acid analogs are of potential use for the noninvasive delineation of regional alterations of fatty acid metabolism by gamma imaging. Since radioactivity from extracted iodine-123 heptadecanoic acid [( 123I]HDA) is released from the myocardium in form of free radioiodide (123I-) the present study was performed to determine whether deiodination of [123I]HDA is related to free fatty acid metabolism. Myocardial production of free radioiodide was measured in rat hearts in vitro and in vivo both under control conditions and after inhibition of fatty acid oxidation. In isolated rat hearts perfused at constant flow with a medium containing [123I]HDA, release of 123I- was markedly reduced during cardioplegia and pharmacologic inhibition of mitochondrial fatty acid transfer with POCA by 67% (p less than 0.005) and 72% (p less than 0.005), respectively. In fasted rats in vivo, 1 min after i.v. injection of [123I]HDA, 51 +/- 5% of myocardial radioactivity was recovered in the aqueous phase, containing free iodide, of myocardial lipid extracts. Aqueous activity was significantly decreased in fed (20 +/- 2%; p less than 0.002) and POCA pretreated (30 +/- 3.7%; p less than 0.05) animals exhibiting reduced oxidation of [14C]palmitate. Thus, deiodination of [123I]HDA was consistently reduced during inhibition of fatty acid oxidation in vitro and in vivo. The results apply to the interpretation of myocardial clearance curves of terminally radioiodinated fatty acid analogs

Studies of the Tc oxidation states in humic acid solutions

International Nuclear Information System (INIS)

Wang Bo; Liu Dejun; Yao Jun

2010-01-01

The oxidation state is an important aspect of the speciation of Tc in groundwater that contained organic substances due to it control the precipitation, complexation, sorption and colloid formation behavior of the Tc under HWL geological disposal conditions. In present work, the oxidation states of Tc were investigated using the LaCl 3 coagulation method and solution extraction method in aqueous solutions in which the humic acid concentration range is from 0 to 20 mg L -1 and the Tc (Ⅶ) concentration range is about 10 -8 mol l -1 . The radiocounting of 99 Tc was determined using liquid scintillation spectrometry. The humic acid will influence the radiocounting ratio of 99 Tc apparently, however, the quenching effect can be restrained once keep the volume of the cocktail to about twenty times of the sample volume. The LaCl 3 coagulation methods were carried out for the investigation of Tc oxidation states in humic acid aqueous systems at about pH 8. The tetraphenylarsonium chloride (IPA)-chloroform extraction method was used also simultaneously to investigation the concentrations of Tc (Ⅳ) and Tc (Ⅶ) for the availability of the LaCl 3 precipitation method, and the experimental results demonstrate that tetravalent technetium and pertechnetate concentrations are well agreement with the LaCl 3 precipitation method. These two experimental results demonstrated that Tc (Ⅶ) is very stable in the Tc (Ⅶ)-humic acid system during a 350 days experimental period, and the Tc (Ⅳ) concentrations are very lower, that is indicate that there didn't oxidizing reactions between the Fluka humic acid and Tc (Ⅶ) in aqueous solutions under anaerobic conditions. That is means the presence of humic acids even in anaerobic groundwater is disadvantage for the retardance of radionuclides. (authors)

Ascorbic acid protects lipids in human plasma and low-density lipoprotein against oxidative damage

Energy Technology Data Exchange (ETDEWEB)

Frei, B. (Department of Nutrition, Harvard School of Public Health, Boston, MA (Unites States))

1991-12-01

The authors exposed human blood plasma and low-density lipoprotein (LDL) to many different oxidative challenges and followed the temporal consumption of endogenous antioxidants in relation to the initiation of oxidative damage. Under all types of oxidizing conditions, ascorbic acid completely protects lipids in plasma and LDL against detectable peroxidative damage as assessed by a specific and highly sensitive assay for lipid peroxidation. Ascorbic acid proved to be superior to the other water-soluble plasma antioxidants bilirubin, uric acid, and protein thiols as well as to the lipoprotein-associated antioxidants alpha-tocopherol, ubiquinol-10, lycopene, and beta-carotene. Although these antioxidants can lower the rate of detectable lipid peroxidation, they are not able to prevent its initiation. Only ascorbic acid is reactive enough to effectively intercept oxidants in the aqueous phase before they can attack and cause detectable oxidative damage to lipids.

All-trans retinoic acid increases oxidative metabolism in mature adipocytes

DEFF Research Database (Denmark)

Mercader, Josep; Madsen, Lise; Felipe, Francisco

2007-01-01

), and to an increased expression of proteins favoring fat oxidation (peroxisome proliferator-activated receptor gamma coactivator-1alpha, uncoupling protein 2, fasting-induced adipose factor, enzymes of mitochondrial fatty acid oxidation). These changes paralleled inactivation of the retinoblastoma protein and were...

The Kinetics and Mechanism for the Oxidation of Nicotinic Acid by Peroxomonosulfate in Acidic Aqueous Medium

Energy Technology Data Exchange (ETDEWEB)

Agrawal, Anju; Sailani, Riya; Gupta, Beena; Khandelwal, C. L.; Sharma, P. D. [Univ. of Rajasthan, Jaipur (India)

2012-04-15

The kinetics of oxidation of nicotinic acid by peroxomonosulfate (PMS) has been studied in acetate buffers. Stoichiometry of the reaction corresponds to the reaction of one mole of the oxidant with a mole of nicotinic acid. N→O product has been confirmed both by UV visible and IR spectroscopy. The reaction is second order viz. first order with respect to each reactant. Activation parameters have also been evaluated. A plausible reaction mechanism is mentioned and the derived kinetic rate law accounts for experimental observations.

The Kinetics and Mechanism for the Oxidation of Nicotinic Acid by Peroxomonosulfate in Acidic Aqueous Medium

International Nuclear Information System (INIS)

Agrawal, Anju; Sailani, Riya; Gupta, Beena; Khandelwal, C. L.; Sharma, P. D.

2012-01-01

The kinetics of oxidation of nicotinic acid by peroxomonosulfate (PMS) has been studied in acetate buffers. Stoichiometry of the reaction corresponds to the reaction of one mole of the oxidant with a mole of nicotinic acid. N→O product has been confirmed both by UV visible and IR spectroscopy. The reaction is second order viz. first order with respect to each reactant. Activation parameters have also been evaluated. A plausible reaction mechanism is mentioned and the derived kinetic rate law accounts for experimental observations

Kinetics of uranium (4) oxidation with nitrous acid in the presence of oxalate-ions in nitric and perchloric acid solutions

International Nuclear Information System (INIS)

Nikitenko, S.I.; Astafurova, L.N.

1991-01-01

Kinetics of uranium (4) oxidation with nitrous acid in the presence of oxalate-ions are studied spectrometrically. It is shown that even at small oxalate concentrations a notable effect of tetravalent uranium stabilization is observed relatively to the oxidation with nitrous acid. In case of a significant excess of oxalate-ions the oxidation rate will be considerably slower as a result of the formation of U(4) bisoxalate complex

Repair of oxidative DNA damage by amino acids.

Science.gov (United States)

Milligan, J R; Aguilera, J A; Ly, A; Tran, N Q; Hoang, O; Ward, J F

2003-11-01

Guanyl radicals, the product of the removal of a single electron from guanine, are produced in DNA by the direct effect of ionizing radiation. We have produced guanyl radicals in DNA by using the single electron oxidizing agent (SCN)2-, itself derived from the indirect effect of ionizing radiation via thiocyanate scavenging of OH. We have examined the reactivity of guanyl radicals in plasmid DNA with the six most easily oxidized amino acids cysteine, cystine, histidine, methionine, tryptophan and tyrosine and also simple ester and amide derivatives of them. Cystine and histidine derivatives are unreactive. Cysteine, methionine, tyrosine and particularly tryptophan derivatives react to repair guanyl radicals in plasmid DNA with rate constants in the region of approximately 10(5), 10(5), 10(6) and 10(7) dm3 mol(-1) s(-1), respectively. The implication is that amino acid residues in DNA binding proteins such as histones might be able to repair by an electron transfer reaction the DNA damage produced by the direct effect of ionizing radiation or by other oxidative insults.

Precipitation of plutonium from acidic solutions using magnesium oxide

International Nuclear Information System (INIS)

Jones, S.A.

1994-01-01

Magnesium oxide will be used as a neutralizing agent for acidic plutonium-containing solutions. It is expected that as the magnesium oxide dissolves, the pH of the solution will rise, and plutonium will precipitate. The resulting solid will be tested for suitability to storage. The liquid is expected to contain plutonium levels that meet disposal limit requirements

Toughening of recycled poly(ethylene terephthalate) with clay-compatibilized rubber phase

Czech Academy of Sciences Publication Activity Database

Kelnar, Ivan; Sukhanov, Valentin; Rotrekl, Jakub; Kaprálková, Ludmila

2010-01-01

Roč. 116, č. 6 (2010), s. 3621-3628 ISSN 0021-8995 R&D Projects: GA ČR GA106/06/0044 Institutional research plan: CEZ:AV0Z40500505 Keywords : recycled poly (ethylene terephthalate) * nanocomposite * clay compatibilization Subject RIV: JI - Composite Materials Impact factor: 1.240, year: 2010

Deuterium oxide as a tool for the study of amino acid metabolism

International Nuclear Information System (INIS)

Mitra, R.; Burton, J.; Varner, J.E.

1976-01-01

We have used deuterium oxide in nontoxic concentrations to study, in intact seedlings, the biosynthesis of amino acids. The extent and pattern of deuteration, as determined by a gas--liquid chromatograph--mass spectrometer system, permits conclusions about the biosynthesis of individual amino acids and also about their exposure to transaminases and other enzymes that might introduce deuterium into specific positions of the amino acid by exchange. This method could be used to study amino acid biogenesis in any organism that can tolerate 20 to 40 percent deuterium oxide for a period of a few hours to a few days

DNAPL remediation with in situ chemical oxidation using potassium permanganate - Part I. Mineralogy of Mn oxide and its dissolution in organic acids

Science.gov (United States)

Li, X. David; Schwartz, Franklin W.

2004-01-01

Previous studies on in situ chemical oxidation of trichloroethylene (TCE) with potassium permanganate indicated that the solid reaction product, Mn oxide, could reduce the permeability of the porous medium and impact the success of dense non-aqueous phase liquid (DNAPL) removal. In order to address the issue of permeability reduction caused by precipitation, this study investigated the mineralogy of Mn oxides and the possibilities of removing the solid precipitates by dissolution. The solid reaction product from the oxidation of TCE by permanganate is semi-amorphous potassium-rich birnessite, which has a layered mineral structure with an interlayer spacing of 7.3 Å. The chemical formula is K 0.854Mn 1.786O 4·1.55H 2O. It has a relatively small specific surface area at 23.6±0.82 m 2/g. Its point of zero charge (pzc) was measured as 3.7±0.4. This birnessite is a relatively active species and could participate in various reactions with existing organic and inorganic matter. The dissolution kinetics of Mn oxide was evaluated in batch experiments using solutions of citric acid, oxalic acid, and ethylenediaminetetraacetic acid (EDTA). Initial dissolution rates were determined to be 0.126 mM/m 2/h for citric acid, 1.35 mM/m 2/h for oxalic acid, and 5.176 mM/m 2/h for EDTA. These rates compare with 0.0025 mM/m 2/h for nitric acid at pH=2. Organic acids dissolve Mn oxide quickly. Reaction rates increase with acid concentration, as tested with citric acid. The dissolution mechanism likely involves proton and ligand-promoted dissolution and reductive dissolution. Citric and oxalic acid can induce ligand-promoted dissolution, while EDTA can induce ligand-promoted and reductive dissolutions. At low pH, proton-promoted dissolution seems to occur with all the acids tested, but this process is not dominant. Reductive dissolution appears to be the most effective process in dissolving the solid, followed by ligand-promoted dissolution. These experiments indicate the significant

Electron donating and acid-base properties of cerium oxide and its mixed oxides with alumina

International Nuclear Information System (INIS)

Sugunan, S.; Jalaja, J.M.

1994-01-01

The electron donating properties of cerium oxide activated at 300, 500 and 800 degC and of its mixed oxides with alumina were examined based on the adsorption of electron acceptors exhibiting different electron affinities. The surface acidity/basicity of the oxides was determined by titrimetry; the H 0,max values are given. The limit of electron transfer from the oxide surface lies within the region of 1.77 and 2.40 eV in terms of the electron affinity of the electron acceptor. Cerium oxide promotes the electron donor nature of alumina while leaving the limit of electron transfer unchanged. 2 tabs., 4 figs., 13 refs

Oxidative degradation of ion-exchange resins in acid medium. Vol. 3

International Nuclear Information System (INIS)

Eskander, S.B.; Ghattas, N.K.

1996-01-01

Volume reduction of spent ion-exchange resins used in nuclear facilities receive increasing importance due to the increase in storage cost, unstable physical and chemical properties and their relatively high specific activity (in some cases up to 1 Ci per liter). The present study is part of research program on the treatment and immobilization of radioactive spent ion-exchange resins simulate; hydrogen peroxide was used for the oxidative degradation of spent ion-exchange resins simulate in sulphuric acid medium. Five liters ring digester developed in Karlsruhe nuclear research center-(KFK)- in germany was the chosen option to perform the oxidation process. The work reported focused on the kinetics and mechanism of the oxidation process. Heating the organic resins in sulphuric acid results in its carbonization and partial oxidation of only 1.7% of the carbon added. Results show that the oxidation reaction is a relatively slow process of first order with K value in the order of 10 -4 min -1 , and the main oxidation product was carbon dioxide. The production of carbon oxide in the off gas stream increased sharply by the addition of hydrogen peroxide to the hot sulphuric acid-resin mixture. The results obtained show that more than 97% of the carbon added was oxidized to carbon dioxide and carbon monoxide. The rate constant value (K) of this reaction was calculated to be (1.69±0.13) x 10 -2 min -1 . The results of gas chromatographic analysis indicate that no significant amounts of hazardous organic materials were detected in the off-gas streams. 6 figs., 4 tabs

Ligand exchange chromatography of free amino acids and proteins on porous microparticulate zirconium oxide

International Nuclear Information System (INIS)

Blackwell, J.A.; Carr, P.W.

1992-01-01

The Lewis acid sites present on the underlying zirconium oxide particles are responsible for the unusual elution sequence for amino acids on copper loaded, phosphated zirconium oxide supports reported in an earlier study. To more thoroughly examine the effect of these strong Lewis acid sites in this paper. The authors have studied ligand exchange chromatography on copper loaded zirconium oxide particles. It is shown here that carboxylate functional groups on amino acid solutes strongly interact with surface Lewis acid sites. Addition of competing hard Lewis bases to the eluent attenuates these specific interactions. The result is a chromatographic system with high selectivity which is also suitable for ligand exchange chromatography of proteins

All-trans retinoic acid increases oxidative metabolism in mature adipocytes

DEFF Research Database (Denmark)

Mercader, Josep; Madsen, Lise; Felipe, Francisco

2007-01-01

BACKGROUND/AIMS: In rodents, retinoic acid (RA) treatment favors loss of body fat mass and the acquisition of brown fat features in white fat depots. In this work, we sought to examine to what extent these RA effects are cell autonomous or dependent on systemic factors. METHODS: Parameters of lipid......), and to an increased expression of proteins favoring fat oxidation (peroxisome proliferator-activated receptor gamma coactivator-1alpha, uncoupling protein 2, fasting-induced adipose factor, enzymes of mitochondrial fatty acid oxidation). These changes paralleled inactivation of the retinoblastoma protein and were...

An allene oxide and 12-oxophytodienoic acid are key intermediates in jasmonic acid biosynthesis by Fusarium oxysporum.

Science.gov (United States)

Oliw, Ernst H; Hamberg, Mats

2017-08-01

Fungi can produce jasmonic acid (JA) and its isoleucine conjugate in large quantities, but little is known about the biosynthesis. Plants form JA from 18:3 n -3 by 13 S -lipoxygenase (LOX), allene oxide synthase, and allene oxide cyclase. Shaking cultures of Fusarium oxysporum f. sp. tulipae released over 200 mg of jasmonates per liter. Nitrogen powder of the mycelia expressed 10 R -dioxygenase-epoxy alcohol synthase activities, which was confirmed by comparison with the recombinant enzyme. The 13 S -LOX of F. oxysporum could not be detected in the cell-free preparations. Incubation of mycelia in phosphate buffer with [17,17,18,18,18- 2 H 5 ]18:3 n -3 led to biosynthesis of a [ 2 H 5 ]12-oxo-13-hydroxy-9 Z ,15 Z -octadecadienoic acid (α-ketol), [ 2 H 5 ]12-oxo-10,15 Z -phytodienoic acid (12-OPDA), and [ 2 H 5 ]13-keto- and [ 2 H 5 ]13 S -hydroxyoctadecatrienoic acids. The α-ketol consisted of 90% of the 13 R stereoisomer, suggesting its formation by nonenzymatic hydrolysis of an allene oxide with 13 S configuration. Labeled and unlabeled 12-OPDA were observed following incubation with 0.1 mM [ 2 H 5 ]18:3 n -3 in a ratio from 0.4:1 up to 47:1 by mycelia of liquid cultures of different ages, whereas 10 times higher concentration of [ 2 H 5 ]13 S -hydroperoxyoctadecatrienoic acid was required to detect biosynthesis of [ 2 H 5 ]12-OPDA. The allene oxide is likely formed by a cytochrome P450 or catalase-related hydroperoxidase. We conclude that F. oxysporum , like plants, forms jasmonates with an allene oxide and 12-OPDA as intermediates. Copyright © 2017 by the American Society for Biochemistry and Molecular Biology, Inc.

The association between low-grade inflammation, iron status and nucleic acid oxidation in the elderly

DEFF Research Database (Denmark)

Broedbaek, Kasper; Siersma, Volkert Dirk; Andersen, Jon T

2011-01-01

This study applied a case-control approach to investigate the association between low-grade inflammation, defined by high values within the normal range of C-reactive protein (CRP) and interleukin-6 (IL-6), and urinary markers of nucleic acid oxidation. No differences in excretion of urinary...... markers of nucleic acid oxidation between cases and controls were found and multivariable linear regression analysis showed no association between urinary markers of nucleic acid oxidation and inflammatory markers. Post-hoc multivariable linear regression analysis showed significant associations between...... suggest that low-grade inflammation only has a negligible impact on whole body nucleic acid oxidation, whereas iron status seems to be of great importance....

Study of photo-oxidative reactivity of sunscreening agents based on photo-oxidation of uric acid by kinetic Monte Carlo simulation

International Nuclear Information System (INIS)

Moradmand Jalali, Hamed; Bashiri, Hadis; Rasa, Hossein

2015-01-01

In the present study, the mechanism of free radical production by light-reflective agents in sunscreens (TiO 2 , ZnO and ZrO 2 ) was obtained by applying kinetic Monte Carlo simulation. The values of the rate constants for each step of the suggested mechanism have been obtained by simulation. The effect of the initial concentration of mineral oxides and uric acid on the rate of uric acid photo-oxidation by irradiation of some sun care agents has been studied. The kinetic Monte Carlo simulation results agree qualitatively with the existing experimental data for the production of free radicals by sun care agents. - Highlights: • The mechanism and kinetics of uric acid photo-oxidation by irradiation of sun care agents has been obtained by simulation. • The mechanism has been used for free radical production of TiO 2 (rutile and anatase), ZnO and ZrO 2 . • The ratios of photo-activity of ZnO to anastase, rutile and ZrO have been obtained. • By doubling the initial concentrations of mineral oxide, the rate of reaction was doubled. • The optimum ratio of initial concentration of mineral oxides to uric acid has been obtained

Thermoplastic elastomers containing 2D nanofillers: montmorillonite, graphene nanoplatelets and oxidized graphene platelets

OpenAIRE

Paszkiewicz Sandra; Pawelec Iwona; Szymczyk Anna; Rosłaniec Zbigniew

2015-01-01

This paper presents a comparative study on which type of platelets nanofiller, organic or inorganic, will affect the properties of thermoplastic elastomer matrix in the stronger manner. Therefore, poly(trimethylene terephthalate-block-poly(tetramethylene oxide) copolymer (PTT-PTMO) based nanocomposites with 0.5 wt.% of clay (MMT), graphene nanoplatelets (GNP) and graphene oxide (GO) have been prepared by in situ polymerization. The structure of the nanocomposites was characterized by transmis...

Mitochondrial fatty acid oxidation defects--remaining challenges

DEFF Research Database (Denmark)

Gregersen, Niels; Andresen, Brage S; Pedersen, Christina B

2008-01-01

Mitochondrial fatty acid oxidation defects have been recognized since the early 1970s. The discovery rate has been rather constant, with 3-4 'new' disorders identified every decade and with the most recent example, ACAD9 deficiency, reported in 2007. In this presentation we will focus on three...

Synthesis of copolymer from lactic acid-polyethylene terephthalate ...

African Journals Online (AJOL)

Bio-plastic has been a need of the hour for the past few decades and the usage of lactic acid (LA) in the production of bio plastic opens a new ... of the environment and also helping in the production of bio-degradable plastics in the run.

Oxidative acid treatment and characterization of new biocarbon from sustainable Miscanthus biomass

International Nuclear Information System (INIS)

Anstey, Andrew; Vivekanandhan, Singaravelu; Rodriguez-Uribe, Arturo; Misra, Manjusri; Mohanty, Amar Kumar

2016-01-01

Oxidative acid treatments of biochar produced from Miscanthus were performed in this study using nitric acid, sulfuric acid, and a mixture of both. The structural and morphological changes of the acid-treated biochar were investigated using Fourier transform infrared spectroscopy (FT-IR), thermogravimetric analysis (TGA), scanning electron microscopy (SEM), Raman spectroscopy, organic elemental analysis and energy-dispersive X-ray spectroscopy (EDS). Improved surface functionality of the treated biochars was observed in their respective FT-IR spectra through the presence of nitro and carboxylic acid functional groups. SEM–EDS and elemental analysis revealed a large increase in the oxygen to carbon ratio in the biochar, which was evidence of chemical oxidation from the acid treatment. Further, TGA study showed the reduced thermal stability of acid-treated biochar over 200 °C due to the increased oxygen content. Acid treatments also influenced the graphitic structure of the biochar, as observed in the Raman spectra. The results suggest that biochar can be successfully functionalized for composite applications and provide a sustainable alternative to petroleum-based carbon additives. - Highlights: • Biochar was investigated as a candidate for renewable functionalized carbon. • Oxidative acid treatment was used to modify the carbon structure. • The chemical and morphological properties of the treated biochar were examined. • Successful chemical modification of biochar was verified through characterization. • Biochar shows potential as a sustainable carbon additive for polymer composites.

Oxidative acid treatment and characterization of new biocarbon from sustainable Miscanthus biomass

Energy Technology Data Exchange (ETDEWEB)

Anstey, Andrew [Bioproducts Discovery and Development Centre (BDDC), Department of Plant Agriculture, Crop Science Building, University of Guelph, Guelph, ON N1G 2W1 (Canada); School of Engineering, Thornbrough Building, University of Guelph, Guelph, ON N1G 2W1 (Canada); Vivekanandhan, Singaravelu [Bioproducts Discovery and Development Centre (BDDC), Department of Plant Agriculture, Crop Science Building, University of Guelph, Guelph, ON N1G 2W1 (Canada); Sustainable Materials and Nanotechnology Lab, Department of Physics, VHNSN College, Virudhunagar 626 001, Tamilnadu (India); Rodriguez-Uribe, Arturo [Bioproducts Discovery and Development Centre (BDDC), Department of Plant Agriculture, Crop Science Building, University of Guelph, Guelph, ON N1G 2W1 (Canada); Misra, Manjusri [Bioproducts Discovery and Development Centre (BDDC), Department of Plant Agriculture, Crop Science Building, University of Guelph, Guelph, ON N1G 2W1 (Canada); School of Engineering, Thornbrough Building, University of Guelph, Guelph, ON N1G 2W1 (Canada); Mohanty, Amar Kumar, E-mail: mohanty@uoguelph.ca [Bioproducts Discovery and Development Centre (BDDC), Department of Plant Agriculture, Crop Science Building, University of Guelph, Guelph, ON N1G 2W1 (Canada); School of Engineering, Thornbrough Building, University of Guelph, Guelph, ON N1G 2W1 (Canada)

2016-04-15

Oxidative acid treatments of biochar produced from Miscanthus were performed in this study using nitric acid, sulfuric acid, and a mixture of both. The structural and morphological changes of the acid-treated biochar were investigated using Fourier transform infrared spectroscopy (FT-IR), thermogravimetric analysis (TGA), scanning electron microscopy (SEM), Raman spectroscopy, organic elemental analysis and energy-dispersive X-ray spectroscopy (EDS). Improved surface functionality of the treated biochars was observed in their respective FT-IR spectra through the presence of nitro and carboxylic acid functional groups. SEM–EDS and elemental analysis revealed a large increase in the oxygen to carbon ratio in the biochar, which was evidence of chemical oxidation from the acid treatment. Further, TGA study showed the reduced thermal stability of acid-treated biochar over 200 °C due to the increased oxygen content. Acid treatments also influenced the graphitic structure of the biochar, as observed in the Raman spectra. The results suggest that biochar can be successfully functionalized for composite applications and provide a sustainable alternative to petroleum-based carbon additives. - Highlights: • Biochar was investigated as a candidate for renewable functionalized carbon. • Oxidative acid treatment was used to modify the carbon structure. • The chemical and morphological properties of the treated biochar were examined. • Successful chemical modification of biochar was verified through characterization. • Biochar shows potential as a sustainable carbon additive for polymer composites.

Fatty acid oxidation changes and the correlation with oxidative stress in different preeclampsia-like mouse models.

Directory of Open Access Journals (Sweden)

Xiaoyan Ding

Full Text Available BACKGROUND: Long-chain 3-hydroxyacyl-CoA dehydrogenase (LCHAD expression is decreased in placenta of some cases of preeclampsia (PE which may result in free fatty acid (FFA increased. High FFA level will induce oxidative stress, so abnormal long-chain fatty acid-oxidation may participate in the pathogenesis of PE through oxidative stress pathway. METHODS: PE-like groups were ApoC3 transgenic mice with abnormal fatty acid metabolism, classical PE-like models with injection of Nw-nitro-L-arginine-methyl ester (L-NA or lipopolysaccharide (LPS and the antiphospholipid syndrome (APS mouse model with β2GPI injection (ApoC3+NS, ApoC3+L-NA, L-NA, LPS and β2GPI groups. The control group was wild-type mice with normal saline injection. Except for β2GPI mice, the other mice were subdivided into pre-implantation (Pre and mid-pregnancy (Mid subgroups by injection time. RESULTS: All PE-like groups showed hypertension and proteinuria except ApoC3+NS mice only showed hypertension. Serum FFA levels increased significantly except in LPS group compared to controls (P<0.05. LCHAD mRNA and protein expression in the liver and placenta was significantly higher for ApoC3+NS, ApoC3+L-NA and β2GPI mice and lower for L-NA mice than controls (P<0.05 but did not differ between LPS mice and controls. P47phox mRNA and protein expression in the liver significantly increased in all PE-like groups except LPS group, while P47phox expression in the placenta only significantly increased in L-NA and β2GPI groups. CONCLUSIONS: Abnormal long-chain fatty acid-oxidation may play a different role in different PE-like models and in some cases participate in the pathogenesis of PE through oxidative stress pathway.

Gallic Acid Grafted Chitosan Has Enhanced Oxidative Stability in Bulk Oils.

Science.gov (United States)

Gim, Seo Yeong; Hong, Seungmi; Kim, Mi-Ja; Lee, JaeHwan

2017-07-01

Gallic acid (GA) was grafted in chitosan and the effects of GA grafted chitosan (GA-g-CS) on the oxidative stability in bulk oil was tested at 60 and 140 °C. To text oxidative stability in oils, headspace oxygen content, conjugated dienoic acid (CDA) value, p-anisidine value (p-AV), and acid value were determined. Chitosan itself did not show antioxidative or prooxidative effects in oils at 60 °C. However, GA-g-CS and GA acted as antioxidants at 60 °C. At 140 °C heating with moisture supplied condition, different results were observed. GA-g-CS acted as antioxidants based on the results of CDA and p-AV. However, chitosan showed the highest oxidative stability based on results of acid value and brown color formation at 140 °C. This could be due to reduction of moisture content by chitosan. GA was continuously released from GA-g-CS in bulk oil. This might have provided extra antioxidant activities to oils. © 2017 Institute of Food Technologists®.

Stable Water Oxidation in Acid Using Manganese-Modified TiO2 Protective Coatings.

Science.gov (United States)

Siddiqi, Georges; Luo, Zhenya; Xie, Yujun; Pan, Zhenhua; Zhu, Qianhong; Röhr, Jason A; Cha, Judy J; Hu, Shu

2018-06-06

Accomplishing acid-stable water oxidation is a critical matter for achieving both long-lasting water-splitting devices and other fuel-forming electro- and photocatalytic processes. Because water oxidation releases protons into the local electrolytic environment, it becomes increasingly acidic during device operation, which leads to corrosion of the photoactive component and hence loss in device performance and lifetime. In this work, we show that thin films of manganese-modified titania, (Ti,Mn)O x , topped with an iridium catalyst, can be used in a coating stabilization scheme for acid-stable water oxidation. We achieved a device lifetime of more than 100 h in pH = 0 acid. We successfully grew (Ti,Mn)O x coatings with uniform elemental distributions over a wide range of manganese compositions using atomic layer deposition (ALD), and using X-ray photoelectron spectroscopy, we show that (Ti,Mn)O x films grown in this manner give rise to closer-to-valence-band Fermi levels, which can be further tuned with annealing. In contrast to the normally n-type or intrinsic TiO 2 coatings, annealed (Ti,Mn)O x films can make direct charge transfer to a Fe(CN) 6 3-/4- redox couple dissolved in aqueous electrolytes. Using the Fe(CN) 6 3-/4- redox, we further demonstrated anodic charge transfer through the (Ti,Mn)O x films to high work function metals, such as iridium and gold, which is not previously possible with ALD-grown TiO 2 . We correlated changes in the crystallinity (amorphous to rutile TiO 2 ) and oxidation state (2+ to 3+) of the annealed (Ti,Mn)O x films to their hole conductivity and electrochemical stability in acid. Finally, by combining (Ti,Mn)O x coatings with iridium, an acid-stable water-oxidation anode, using acid-sensitive conductive fluorine-doped tin oxides, was achieved.

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.

Electrochemical degradation of clofibric acid in water by anodic oxidation

Energy Technology Data Exchange (ETDEWEB)

Sires, Ignasi [Laboratori de Ciencia i Tecnologia Electroquimica de Materials, Departament de Quimica Fisica, Facultat de Quimica, Universitat de Barcelona, Marti i Franques 1-11, 08028 Barcelona (Spain); Cabot, Pere Lluis [Laboratori de Ciencia i Tecnologia Electroquimica de Materials, Departament de Quimica Fisica, Facultat de Quimica, Universitat de Barcelona, Marti i Franques 1-11, 08028 Barcelona (Spain); Centellas, Francesc [Laboratori de Ciencia i Tecnologia Electroquimica de Materials, Departament de Quimica Fisica, Facultat de Quimica, Universitat de Barcelona, Marti i Franques 1-11, 08028 Barcelona (Spain); Garrido, Jose Antonio [Laboratori de Ciencia i Tecnologia Electroquimica de Materials, Departament de Quimica Fisica, Facultat de Quimica, Universitat de Barcelona, Marti i Franques 1-11, 08028 Barcelona (Spain); Rodriguez, Rosa Maria [Laboratori de Ciencia i Tecnologia Electroquimica de Materials, Departament de Quimica Fisica, Facultat de Quimica, Universitat de Barcelona, Marti i Franques 1-11, 08028 Barcelona (Spain); Arias, Conchita [Laboratori de Ciencia i Tecnologia Electroquimica de Materials, Departament de Quimica Fisica, Facultat de Quimica, Universitat de Barcelona, Marti i Franques 1-11, 08028 Barcelona (Spain); Brillas, Enric [Laboratori de Ciencia i Tecnologia Electroquimica de Materials, Departament de Quimica Fisica, Facultat de Quimica, Universitat de Barcelona, Marti i Franques 1-11, 08028 Barcelona (Spain)]. E-mail: brillas@ub.edu

2006-10-05

Aqueous solutions containing the metabolite clofibric acid (2-(4-chlorophenoxy)-2-methylpropionic acid) up to close to saturation in the pH range 2.0-12.0 have been degraded by anodic oxidation with Pt and boron-doped diamond (BDD) as anodes. The use of BDD leads to total mineralization in all media due to the efficient production of oxidant hydroxyl radical ({center_dot}OH). This procedure is then viable for the treatment of wastewaters containing this compound. The effect of pH, apparent current density, temperature and metabolite concentration on the degradation rate, consumed specific charge and mineralization current efficiency has been investigated. Comparative treatment with Pt yields poor decontamination with complete release of stable chloride ion. When BDD is used, this ion is oxidized to Cl{sub 2}. Clofibric acid is more rapidly destroyed on Pt than on BDD, indicating that it is more strongly adsorbed on the Pt surface enhancing its reaction with {center_dot}OH. Its decay kinetics always follows a pseudo-first-order reaction and the rate constant for each anode increases with increasing apparent current density, being practically independent of pH and metabolite concentration. Aromatic products such as 4-chlorophenol, 4-chlorocatechol, 4-chlororesorcinol, hydroquinone, p-benzoquinone and 1,2,4-benzenetriol are detected by gas chromatography-mass spectrometry (GC-MS) and reversed-phase chromatography. Tartronic, maleic, fumaric, formic, 2-hydroxyisobutyric, pyruvic and oxalic acids are identified as generated carboxylic acids by ion-exclusion chromatography. These acids remain stable in solution using Pt, but they are completely converted into CO{sub 2} with BDD. A reaction pathway for clofibric acid degradation involving all these intermediates is proposed.

Electrochemical degradation of clofibric acid in water by anodic oxidation

International Nuclear Information System (INIS)

Sires, Ignasi; Cabot, Pere Lluis; Centellas, Francesc; Garrido, Jose Antonio; Rodriguez, Rosa Maria; Arias, Conchita; Brillas, Enric

2006-01-01

Aqueous solutions containing the metabolite clofibric acid (2-(4-chlorophenoxy)-2-methylpropionic acid) up to close to saturation in the pH range 2.0-12.0 have been degraded by anodic oxidation with Pt and boron-doped diamond (BDD) as anodes. The use of BDD leads to total mineralization in all media due to the efficient production of oxidant hydroxyl radical (·OH). This procedure is then viable for the treatment of wastewaters containing this compound. The effect of pH, apparent current density, temperature and metabolite concentration on the degradation rate, consumed specific charge and mineralization current efficiency has been investigated. Comparative treatment with Pt yields poor decontamination with complete release of stable chloride ion. When BDD is used, this ion is oxidized to Cl 2 . Clofibric acid is more rapidly destroyed on Pt than on BDD, indicating that it is more strongly adsorbed on the Pt surface enhancing its reaction with ·OH. Its decay kinetics always follows a pseudo-first-order reaction and the rate constant for each anode increases with increasing apparent current density, being practically independent of pH and metabolite concentration. Aromatic products such as 4-chlorophenol, 4-chlorocatechol, 4-chlororesorcinol, hydroquinone, p-benzoquinone and 1,2,4-benzenetriol are detected by gas chromatography-mass spectrometry (GC-MS) and reversed-phase chromatography. Tartronic, maleic, fumaric, formic, 2-hydroxyisobutyric, pyruvic and oxalic acids are identified as generated carboxylic acids by ion-exclusion chromatography. These acids remain stable in solution using Pt, but they are completely converted into CO 2 with BDD. A reaction pathway for clofibric acid degradation involving all these intermediates is proposed

Stereoselective and nonstereoselective effects of ibuprofen enantiomers on mitochondrial beta-oxidation of fatty acids

International Nuclear Information System (INIS)

Freneaux, E.; Fromenty, B.; Berson, A.; Labbe, G.; Degott, C.; Letteron, P.; Larrey, D.; Pessayre, D.

1990-01-01

The effects of the R-(-) and S-(+)ibuprofen enantiomers were first studied in vitro with mouse liver mitochondria incubated in the presence of various concentrations of exogenous coenzyme A. In the presence of a low concentration of coenzyme A (2.5 microM), the R-(-)enantiomer (which forms an acylcoenzyme A) inhibited stereoselectively the beta oxidation of [1- 14 C]palmitic acid but not that of [1- 14 C]palmitoyl-L-carnitine (which can directly enter the mitochondria). In the presence, however, of a concentration of coenzyme A (50 microM) reproducing that present in liver cell cytosol, both enantiomers (2 mM) slightly inhibited the beta oxidation of [1- 14 C]palmitic acid and markedly inhibited the beta oxidation of [1- 14 C]octanoic acid and [1- 14 C]butyric acid. In vivo, both enantiomers (1 mmol.kg-1) similarly inhibited the formation of [ 14 C]CO 2 from [1- 14 C]fatty acids. Both enantiomers similarly decreased plasma ketone bodies. Both similarly increased hepatic triglycerides, and both produced mild microvesicular steatosis of the liver. We conclude that both ibuprofen enantiomers inhibit beta oxidation of fatty acids in vitro and in vivo. In addition, the R-(-)enantiomer may stereoselectively sequester coenzyme A; at low concentrations of coenzyme A in vitro, this may stereoselectively inhibit the mitochondrial uptake and beta oxidation of long chain fatty acids

Effect of impaired fatty acid oxidation on myocardial kinetics of 11C- and 123I-labelled fatty acids

International Nuclear Information System (INIS)

Lerch, R.

1986-01-01

Positron emission tomography with palmitate 11 C and single photon imaging with terminally radioiodinated fatty acid analogues (FFA 123 I) were evaluated for the noninvasive assessment of regional myocardial fatty acid metabolism during ischaemia. Decreased uptake of tracer and delayed clearance of activity in the ischaemic myocardium were reported for both 11 C- and 123 I-labelled compounds. However, since during ischaemia both myocardial blood flow and oxidative metabolism are reduced concomitantly, either factor can be responsible for the changes observed. Experimental preparations in which fatty acid metabolism can be modified independently of flow are helpful for the characterization of the relationship between metabolism and myocardial kinetics of labelled fatty acids. Results obtained during flow-independent inhibition of fatty acid oxidation include the following observations: - In dogs with controlled coronary perfusion the rate of clearance of palmitate 11 C-activity is decreased during diminished delivery of oxygen, regardless of whether myocardial perfusion is concomitantly reduced or not. - In isolated rabbit hearts perfused at normal flow, the extraction of FFA 123 I is decreased during hypoxia. - During pharmacological inhibition of fatty acid oxidation the deiodination of FFA 123 I is markedly reduced in rat hearts in vivo and in vitro. (orig.)

Aerobic Oxidation of Xylose to Xylaric acid in Water over Pt Catalysts.

Science.gov (United States)

Saha, Basudeb; Sadula, Sunitha

2018-05-02

Energy-efficient catalytic conversion of biomass intermediates to functional chemicals can enable bio-products viable. Herein, we report an efficient and low temperature aerobic oxidation of xylose to xylaric acid, a promising bio-based chemical for the production of glutaric acid, over commercial catalysts in water. Among several heterogeneous catalysts investigated, Pt/C exhibits the best activity. Systematic variation of reaction parameters in the pH range of 2.5 to 10 suggests that the reaction is fast at higher temperatures but high C-C scission of intermediate C5-oxidized products to low carbon carboxylic acids undermines xylaric acid selectivity. The C-C cleavage is also high in basic solution. The oxidation at neutral pH and 60 C achieves the highest xylaric acid yield (64%). O2 pressure and Pt-amount have significant influence on the reactivity. Decarboxylation of short chain carboxylic acids results in formation of CO2, causing some carbon loss; however such decarboxylation is slow in the presence of xylose. The catalyst retained comparable activity, in terms of product selectivity, after five cycles with no sign of Pt leaching. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Oxidation of aromatic alcohols on zeolite-encapsulated copper amino acid complexes

Energy Technology Data Exchange (ETDEWEB)

Ernst, S.; Teixeira Florencio, J.M. [Kaiserslautern Univ. (Germany). Dept. of Chemistry, Chemical Technology

1998-12-31

Copper complexes of the amino acids histidine, arginine and lysine have been introduced into the supercages of zeolite Y and, for the first time, into the large intracrystalline cavities of zeolites EMT and MCM-22. The resulting host/guest compounds are characterized by X-ray powder diffraction, UV/VIS-spectroscopy in the diffuse reflectance mode and by catalytic tests in the liquid-phase oxidation of aromatic alcohols (viz. benzyl alcohol, 2- and 3-methylbenzyl alcohol and 2,5-dimethylbenzyl alcohol) with tertiary-butylhydroperoxide as oxidant. It was observed that intracrystalline copper-amino acid complexes possess remarkable catalytic activity, yielding the corresponding aromatic aldehydes and acids. (orig.)

Multi-objective optimization of p-xylene oxidation process using an improved self-adaptive differential evolution algorithm

Institute of Scientific and Technical Information of China (English)

Lili Tao; Bin Xu; Zhihua Hu; Weimin Zhong

2017-01-01

The rise in the use of global polyester fiber contributed to strong demand of the Terephthalic acid (TPA). The liquid-phase catalytic oxidation of p-xylene (PX) to TPA is regarded as a critical and efficient chemical process in industry [1]. PX oxidation reaction involves many complex side reactions, among which acetic acid combustion and PX combustion are the most important. As the target product of this oxidation process, the quality and yield of TPA are of great concern. However, the improvement of the qualified product yield can bring about the high energy consumption, which means that the economic objectives of this process cannot be achieved simulta-neously because the two objectives are in conflict with each other. In this paper, an improved self-adaptive multi-objective differential evolution algorithm was proposed to handle the multi-objective optimization prob-lems. The immune concept is introduced to the self-adaptive multi-objective differential evolution algorithm (SADE) to strengthen the local search ability and optimization accuracy. The proposed algorithm is successfully tested on several benchmark test problems, and the performance measures such as convergence and divergence metrics are calculated. Subsequently, the multi-objective optimization of an industrial PX oxidation process is carried out using the proposed immune self-adaptive multi-objective differential evolution algorithm (ISADE). Optimization results indicate that application of ISADE can greatly improve the yield of TPA with low combustion loss without degenerating TA quality.

Sol-gel synthesis and characterization of hybrid inorganic-organic Tb(III)-terephthalate containing layered double hydroxides

Science.gov (United States)

Smalenskaite, A.; Salak, A. N.; Ferreira, M. G. S.; Skaudzius, R.; Kareiva, A.

2018-06-01

Mg3/Al1 and Mg3Al1-xTbx layered double hydroxides (LDHs) intercalated with terephthalate anion were synthesized using sol-gel method. The obtained materials were characterized by X-ray diffraction (XRD) analysis, infrared (FTIR) spectroscopy, fluorescence spectroscopy (FLS) and scanning electron microscopy (SEM). The Tb3+ substitution effects in the Mg3Al1-xTbx LDHs were investigated by changing the Tb3+ concentration in the cation layers. The study indicates that the organic guest-terephthalate in the interlayer spacing of the LDH host influences the luminescence of the hybrid inorganic-organic materials.

Oxidative stability of structured lipids produced from sunflower oil and caprylic acid

DEFF Research Database (Denmark)

Timm Heinrich, Maike; Xu, Xuebing; Nielsen, Nina Skall

2003-01-01

Traditional sunflower oil (SO), randomized lipid (RL) and specific structured lipid (SL), both produced from SO and tricaprylin/caprylic acid, respectively, were stored for up to 12 wk to compare their oxidative stabilities by chemical and sensory analyses. Furthermore, the effect of adding...... a commercial antioxidant blend Grindox 117 (propyl gallate/citric acid/ascorbyl palmitate) or gallic acid to the SL was investigated. The lipid type affected the oxidative stability: SL was less stable than SO and RL. The reduced stability was most likely caused by both the structure of the lipid...

Enhanced photoluminescence in transparent thin films of polyaniline–zinc oxide nanocomposite prepared from oleic acid modified zinc oxide nanoparticles

Energy Technology Data Exchange (ETDEWEB)

Sajimol Augustine, M., E-mail: sajimollazar@gmail.com [Department of Physics, St. Teresa' s College, Kochi-11, Kerala (India); Jeeju, P.P.; Varma, S.J.; Francis Xavier, P.A. [Division for Research in Advanced Materials, Department of Physics, Cochin University of Science and Technology, Kochi-22, Kerala (India); Jayalekshmi, S., E-mail: lakshminathcusat@gmail.com [Division for Research in Advanced Materials, Department of Physics, Cochin University of Science and Technology, Kochi-22, Kerala (India)

2014-07-01

Oleic acid capped zinc oxide (ZnO) nanoparticles have been synthesized by a wet chemical route. The chemical oxidative method is employed to synthesize polyaniline (PANI) and PANI/ZnO nanocomposites doped with four different dopants such as orthophosphoric acid (H{sub 3}PO{sub 4}), hydrochloric acid (HCl), naphthalene-2-sulphonic acid and camphor sulphonic acid (CSA). The samples have been structurally characterized by X-ray diffraction (XRD), field emission scanning electron microscopy and Fourier transform infrared (FT-IR) spectroscopic techniques. A comparison of the photoluminescence (PL) emission intensity of PANI and PANI/ZnO nanocomposites is attempted. The enhanced PL intensity in PANI/ZnO nanocomposites is caused by the presence of nanostructured and highly fluorescent ZnO in the composites. It has been observed that, among the composites, the H{sub 3}PO{sub 4} doped PANI/ZnO nanocomposite is found to exhibit the highest PL intensity because of the higher extent of (pi) conjugation and the more orderly arrangement of the benzenoid and quinonoid units. In the present work, transparent thin films of PANI and PANI/ZnO nanocomposite for which PL intensity is found to be maximum, have been prepared after re-doping with CSA by the spin-coating technique. The XRD pattern of the PANI/ZnO film shows exceptionally good crystallanity compared to that of pure PANI, which suggests that the addition of ZnO nanocrystals helps in enhancing the crystallanity of the PANI/ZnO nanocomposite. There is a significant increase in the PL emission intensity of the PANI/ZnO nanocomposite film making it suitable for the fabrication of optoelectronic devices. - Highlights: • Oleic acid capped zinc oxide nanoparticles are synthesized by wet chemical method. • Polyaniline/zinc oxide nanocomposites are prepared by in-situ polymerization. • Polyaniline and polyaniline/zinc oxide thin films are deposited using spin-coating. • Enhanced photoluminescence is observed in polyaniline

Effect of the Linker in Terephthalate-Functionalized Conducting Redox Polymers

International Nuclear Information System (INIS)

Yang, Li; Huang, Xiao; Gogoll, Adolf; Strømme, Maria; Sjödin, Martin

2016-01-01

The combination of high capacity redox active pendent groups and conducting polymers, realized in conducting redox polymers (CRPs), provides materials with high charge storage capacity that are electronically conducting which makes CRPs attractive for electrical energy storage applications. In this report, six polythiophene and poly(3,4-ethylenedioxythiophene)(PEDOT)-based CRPs with a diethyl terephthalate unit covalently bound to the polymer chain by various linkers have been synthesized and characterized electrochemically. The effects of the choice of polymer backbone and of the nature of the link on the electrochemistry, and in particular the cycling stability of these polymers, are discussed. All CRPs show both the doping of the polymer backbone as well as the redox behavior of the pendent groups and the redox potential of the pendent groups in the CRPs is close to that of corresponding monomer, indicating insignificant interaction between the pendant and the polymer backbone. While all CRPs show various degrees of charge decay upon electrochemical redox conversion, the PEDOT-based CRPs show significantly improved stability compared to the polythiophene counterparts. Moreover, we show that by the right choice of link the cycling stability of diethyl terephthalate substituted PEDOT-based CRPs can be significantly improved.

Protective effects of dietary glycine and glutamic acid toward the toxic effects of oxidized mustard oil in rabbits.

Science.gov (United States)

Zeb, Alam; Rahman, Saleem Ur

2017-01-25

The protective role of glycine and glutamic acid against the toxic effects of oxidized oil was studied for the first time. Mustard seed oil was thermally oxidized and characterized for quality characteristics and polyphenolic composition using reversed phase HPLC-DAD. Significant changes in the quality characteristics occurred with thermal oxidation. Fourteen polyphenolic compounds were identified and quantified in oils. Quercetin-3-glucoside, quercetin-3-feruloylsophoroside, catechin, quercetin-3-rutinoside, quercetin-3,7-diglucoside, sinapic acid and vanillic acid hexoside were the major compounds in the fresh and oxidized oil. Oxidized, un-oxidized mustard oils, glycine and glutamic acid were given to rabbits alone or in combination. The biochemical responses were studied in terms of haematological and biochemical parameters and histopathology. It has been observed that biochemical and haematological parameters were adversely affected by the oxidized oil, while supplementation of both amino acids was beneficial in normalizing these parameters. Both amino acids alone have no significant effects, however, oxidized oil affected the liver by enhancing fat accumulation, causing hepatitis, reactive Kupffer cells and necrosis. The co-administration of oxidized oils with glycine or glutamic acid revealed significant recovery of the liver structure and function. In conclusion, glycine or glutamic acid is beneficial and protective against food toxicity and can be considered as an ameliorative food supplement.

Study of photo-oxidative reactivity of sunscreening agents based on photo-oxidation of uric acid by kinetic Monte Carlo simulation

Energy Technology Data Exchange (ETDEWEB)

Moradmand Jalali, Hamed; Bashiri, Hadis, E-mail: hbashiri@kashanu.ac.ir; Rasa, Hossein

2015-05-01

In the present study, the mechanism of free radical production by light-reflective agents in sunscreens (TiO{sub 2}, ZnO and ZrO{sub 2}) was obtained by applying kinetic Monte Carlo simulation. The values of the rate constants for each step of the suggested mechanism have been obtained by simulation. The effect of the initial concentration of mineral oxides and uric acid on the rate of uric acid photo-oxidation by irradiation of some sun care agents has been studied. The kinetic Monte Carlo simulation results agree qualitatively with the existing experimental data for the production of free radicals by sun care agents. - Highlights: • The mechanism and kinetics of uric acid photo-oxidation by irradiation of sun care agents has been obtained by simulation. • The mechanism has been used for free radical production of TiO{sub 2} (rutile and anatase), ZnO and ZrO{sub 2}. • The ratios of photo-activity of ZnO to anastase, rutile and ZrO have been obtained. • By doubling the initial concentrations of mineral oxide, the rate of reaction was doubled. • The optimum ratio of initial concentration of mineral oxides to uric acid has been obtained.

Role Of Ascorbic Acid In Imparting Tolerance To Plants Against Oxidizing Pollutants

Directory of Open Access Journals (Sweden)

Priyanka Sharma

2015-08-01

Full Text Available Ascorbic acid is an antioxidant in plants which play important role in activation of many physiological and defense mechanisms. The level of ascorbic acid in plants is determinant of its tolerance against the adverse effect of oxidizing pollutants. The present study tries to relate the variation in ascorbic acid content with the tolerance and sensitivity of two selected plant species viz. Azadirachtaindica and Pongamiapinnata by calculating their Air Pollution Tolerance Index APTI during winter season from November to March in the urban city Delhi of North India. Moreover ascorbic acid is also an important part of chloroplast it protects different components of photosynthetic system from oxidative stress. Thus to understand the role of ascorbic acid in imparting tolerance to plants against oxidizing pollutants the changes in chlorophyll content of the selected plant species with variation in ambient ozone concentration was analysed. It was found that as per APTI values Azadirachta sp. came under tolerant range with highest ascorbic acid content whereas Pongamia sp. was under intermediate range with less ascorbic acid content. It was statistically established that ozone has no significant relation with chlorophyll content of Azadirachta sp. which has the highest ascorbic acid content. Whereas ambient ozone concentrations showed significant negative relation with the chlorophyll content of Pongamia sp. p 0.05. Thus it was observed that the plants with high ascorbic acid content are tolerant and have greater ability to remediate pollutants.

Relationship between fatty acid delivery and fatty acid oxidation during strenuous exercise

NARCIS (Netherlands)

Romijn, J. A.; Coyle, E. F.; Sidossis, L. S.; Zhang, X. J.; Wolfe, R. R.

1995-01-01

To evaluate the extent to which decreased plasma free fatty acid (FFA) concentration contributes to the relatively low rates of fat oxidation during high-intensity exercise, we studied FFA metabolism in six endurance-trained cyclists during 20-30 min of exercise [85% of maximal O2 uptake (VO2max)].

Stereoselective and nonstereoselective effects of ibuprofen enantiomers on mitochondrial beta-oxidation of fatty acids

Energy Technology Data Exchange (ETDEWEB)

Freneaux, E.; Fromenty, B.; Berson, A.; Labbe, G.; Degott, C.; Letteron, P.; Larrey, D.; Pessayre, D. (Unite de Recherches de Physiolopathologie Hepatique (INSERM U-24), Hopital Beaujon, Clichy (France))

1990-11-01

The effects of the R-(-) and S-(+)ibuprofen enantiomers were first studied in vitro with mouse liver mitochondria incubated in the presence of various concentrations of exogenous coenzyme A. In the presence of a low concentration of coenzyme A (2.5 microM), the R-(-)enantiomer (which forms an acylcoenzyme A) inhibited stereoselectively the beta oxidation of (1-{sup 14}C)palmitic acid but not that of (1-{sup 14}C)palmitoyl-L-carnitine (which can directly enter the mitochondria). In the presence, however, of a concentration of coenzyme A (50 microM) reproducing that present in liver cell cytosol, both enantiomers (2 mM) slightly inhibited the beta oxidation of (1-{sup 14}C)palmitic acid and markedly inhibited the beta oxidation of (1-{sup 14}C)octanoic acid and (1-{sup 14}C)butyric acid. In vivo, both enantiomers (1 mmol.kg-1) similarly inhibited the formation of ({sup 14}C)CO{sub 2} from (1-{sup 14}C)fatty acids. Both enantiomers similarly decreased plasma ketone bodies. Both similarly increased hepatic triglycerides, and both produced mild microvesicular steatosis of the liver. We conclude that both ibuprofen enantiomers inhibit beta oxidation of fatty acids in vitro and in vivo. In addition, the R-(-)enantiomer may stereoselectively sequester coenzyme A; at low concentrations of coenzyme A in vitro, this may stereoselectively inhibit the mitochondrial uptake and beta oxidation of long chain fatty acids.

Recycling of waste poly(ethylene terephthalate) with castor oil using microwave heating

Czech Academy of Sciences Publication Activity Database

Beneš, Hynek; Slabá, J.; Walterová, Zuzana; Rais, David

2013-01-01

Roč. 98, č. 11 (2013), s. 2232-2243 ISSN 0141-3910 R&D Projects: GA MPO 2A-2TP1/135 Institutional support: RVO:61389013 Keywords : poly(ethylene terephthalate) * castor oil * chemical recycling Subject RIV: CD - Macromolecular Chemistry Impact factor: 2.633, year: 2013

Dissolution study of thorium-uranium oxides in aqueous triflic acid solutions

Energy Technology Data Exchange (ETDEWEB)

Bulemela, E.; Bergeron, A.; Stoddard, T. [Canadian Nuclear Laboratories - CNL, 286 Plant Rd., Chalk River, Ontario, K0J 1J0 (Canada)

2016-07-01

The dissolution of sintered mixed oxides of thorium with uranium in various concentrations of trifluoromethanesulfonic (triflic) acid solutions was investigated under reflux conditions to evaluate the suitability of the method. Various fragment sizes (1.00 mm < x < 7.30 mm) of sintered (Th,U)O{sub 2} and simulated high-burnup nuclear fuel (SIMFUEL) were almost completely dissolved in a few hours, which implies that triflic acid could be used as an alternative to the common dissolution method, involving nitric acid-hydrofluoric acid mixture. The influence of acid concentration, composition of the solids, and reaction time on the dissolution yield of Th and U ions was studied using Inductively Coupled Plasma - Mass Spectrometry (ICP-MS). The dissolution rate was found to depend upon the triflic acid concentration and size of the solid fragments, with near complete dissolution for the smallest fragments occurring in boiling 87% w/w triflic acid. The formation of Th and U ions in solution appears to occur at the same rate as the triflic acid simultaneously reacts with the constituent oxides as evidenced by the results of a constant U/Th concentration ratio with the progress of the dissolution. (authors)

Selective oxidation of glycerol to formic acid in highly concentrated aqueous solutions with molecular oxygen using V-substituted phosphomolybdic acids

KAUST Repository

Zhang, Jizhe

2014-01-01

Formic acid is an important commodity chemical as well as a promising medium for hydrogen storage and hydrogen production. In this paper, we report that formic acid can be produced through selective oxidation of glycerol, a low-cost by-product of biodiesel, by using vanadium-substituted phosphomolybdic acids as catalysts and molecular oxygen as the oxidant. Significantly, this catalytic system allows for high-concentration conversions and thus leads to exceptional efficiency. Specifically, 3.64 g of formic acid was produced from 10 g of glycerol/water (50/50 in weight) solution. © 2014 the Partner Organisations.

The graphene nanopowder for electro-catalytic oxidation of dopamine and uric acid in the presence of ascorbic acid

Institute of Scientific and Technical Information of China (English)

Yuan; Bu; Wenle; Dai; Nan; Li; Xinran; Zhao; Xia; Zuo

2013-01-01

The graphene nanopowder for electro-catalytic oxidation of dopamine and uric acid in the presence of ascorbic acid has been investigated by cyclic voltammetry,linear polarization and chronoamperometry.The graphene nanopowder modified electrode was prepared using the drop coating method,which displayed excellent electrocatalytic activity towards the oxidation of dopamine and uric acid compared with the bare glassy carbon electrode in phosphate buffer solution at pH=7.0.Linear responses for dopamine and uric acid were obtained in the ranges of3.3μmol/L to 249.1μmol/L and 6.7μmol/L to 386.3μmol/L with detection limits of 1.5μmol/L and 2.7μmol/L(S/N=3),respectively.The response time was less than 2 s in case of dopamine and 3 s in case of uric acid,respectively.The results demonstrated that the graphene nanopowder had potential for detecting dopamine and uric acid.

Graphene oxide for solid-phase extraction of bioactive phenolic acids.

Science.gov (United States)

Hou, Xiudan; Wang, Xusheng; Sun, Yingxin; Wang, Licheng; Guo, Yong

2017-05-01

A solid-phase extraction (SPE) method for the efficient analysis of trace phenolic acids (PAs, caffeic acid, ferulic acid, protocatechuic acid, cinnamic acid) in urine was established. In this work, a graphene oxide (GO) coating was grafted onto pure silica to be investigated as SPE material. The prepared GO surface had a layered and wrinkled structure that was rough and well organized, which could provide more open adsorption sites. Owing to its hydrophilicity and polarity, GO showed higher extraction efficiency toward PAs than reduced GO did, in agreement with the theoretical calculation results performed by Gaussian 09 software. The adsorption mechanism of PAs on GO@Sil was also investigated through static state and kinetic state adsorption experiments, which showed a monolayer surface adsorption. Extraction capacity of the as-prepared material was optimized using the response surface methodology. Under the optimized conditions, the as-established method provided wide linearity range (2-50 μg L -1 for protocatechuic acid and 1-50 μg L -1 for caffeic acid, ferulic acid, and cinnamic acid) and low limits of detection (0.25-1 μg L -1 ). Finally, the established method was applied for the analysis of urine from two healthy volunteers. The results indicate that the prepared material is a practical, cost-effective medium for the extraction and determination of phenolic acids in complex matrices. Graphical Abstract A graphene oxide coating was grafted onto pure silica as the SPE material for the extraction of phenolic acids in urines and the extraction mechanism was also mainly investigated.

Chemoproteomic Profiling of Acetanilide Herbicides Reveals Their Role in Inhibiting Fatty Acid Oxidation.

Science.gov (United States)

Counihan, Jessica L; Duckering, Megan; Dalvie, Esha; Ku, Wan-Min; Bateman, Leslie A; Fisher, Karl J; Nomura, Daniel K

2017-03-17

Acetanilide herbicides are among the most widely used pesticides in the United States, but their toxicological potential and mechanisms remain poorly understood. Here, we have used chemoproteomic platforms to map proteome-wide cysteine reactivity of acetochlor (AC), the most widely used acetanilide herbicide, in vivo in mice. We show that AC directly reacts with >20 protein targets in vivo in mouse liver, including the catalytic cysteines of several thiolase enzymes involved in mitochondrial and peroxisomal fatty acid oxidation. We show that the fatty acids that are not oxidized, due to impaired fatty acid oxidation, are instead diverted into other lipid pathways, resulting in heightened free fatty acids, triglycerides, cholesteryl esters, and other lipid species in the liver. Our findings show the utility of chemoproteomic approaches for identifying novel mechanisms of toxicity associated with environmental chemicals like acetanilide herbicides.

Medium-chain fatty acids undergo elongation before β-oxidation in fibroblasts

International Nuclear Information System (INIS)

Jones, Patricia M.; Butt, Yasmeen; Messmer, Bette; Boriak, Richard; Bennett, Michael J.

2006-01-01

Although mitochondrial fatty acid β-oxidation (FAO) is considered to be well understood, further elucidation of the pathway continues through evaluation of patients with FAO defects. The FAO pathway can be examined by measuring the 3-hydroxy-fatty acid (3-OHFA) intermediates. We present a unique finding in the study of this pathway: the addition of medium-chain fatty acids to the culture media of fibroblasts results in generation of 3-OHFAs which are two carbons longer than the precursor substrate. Cultured skin fibroblasts from normal and LCHAD-deficient individuals were grown in media supplemented with various chain-length fatty acids. The cell-free medium was analyzed for 3-OHFAs by stable-isotope dilution gas-chromatography/mass-spectrometry. Our finding suggests that a novel carbon chain-length elongation process precedes the oxidation of medium-chain fatty acids. This previously undescribed metabolic step may have important implications for the metabolism of medium-chain triglycerides, components in the dietary treatment of a number of disorders

Lipid oxidation and fatty acid composition in salt-dried yellow croaker ( Pseudosciaena polyactis) during processing

Science.gov (United States)

Cai, Qiuxing; Wu, Yanyan; Li, Laihao; Wang, Yueqi; Yang, Xianqing; Zhao, Yongqiang

2017-10-01

Lipid oxidation in salt-dried yellow croaker ( Pseudosciaena polyactis) was evaluated during processing with commonly used analytical indices, such as the peroxide value (POV), the thiobarbituric acid reactive substances (TBARS) value, and oxidative-relative lipoxygenase (LOX) activity. Additionally, fatty acids were analyzed using gas chromatography-mass spectrometry. Both POV and TBARS increased significantly ( P acids were identified. Combined eicosapentaenoic acid (EPA; C20:5n3) and docosahexaenoic acid (DHA; C22:6n3) content varied between (19.20 ± 0.37) mg g-1 and (23.45 ± 1.05) mg g-1. The polyunsaturated fatty acid/saturated fatty acid (PUFA/SFA) ratio in yellow croaker was 0.73-1.10, and the n-6/n-3 PUFA ratio was approximately 0.13-0.20. The contents of most fatty acids varied significantly ( P acids are potential markers for evaluating lipid oxidation in fish muscle because there was a significant correlation between these markers and TBARS and LOX activity ( P 0.931.

Zero-order release of lysozyme from (poly)ethylene glycol)/poly(butylene terephthalate) matrices

NARCIS (Netherlands)

Bezemer, J.M.; Radersma, R.; Grijpma, Dirk W.; Dijkstra, Pieter J.; Feijen, Jan; van Blitterswijk, Clemens

2000-01-01

Protein release from a series of biodegradable poly(ether ester) multiblock copolymers, based on poly(ethylene glycol) (PEG) and poly(butylene terephthalate) (PBT) was investigated. Lysozyme-containing PEG/PBT films and microspheres were prepared using an emulsion technique. Proteins were

21 CFR 177.1345 - Ethylene/1,3-phenylene oxyethylene isophthalate/ terephthalate copolymer.

Science.gov (United States)

2010-04-01

... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Ethylene/1,3-phenylene oxyethylene isophthalate... Ethylene/1,3-phenylene oxyethylene isophthalate/ terephthalate copolymer. Ethylene/1, 3-phenylene... polymers complying with § 177.1630. (a) Identity. For the purpose of this section, ethylene/1,3-phenylene...

Impaired fatty acid oxidation as a cause for lipotoxicity in cardiomyocytes

Energy Technology Data Exchange (ETDEWEB)

Haffar, T. [Université de Montreal (Canada); Montreal Heart Institute (Canada); Bérubé-Simard, F. [Montreal Heart Institute (Canada); Bousette, N., E-mail: nicolas.bousette@umontreal.ca [Université de Montreal (Canada); Montreal Heart Institute (Canada)

2015-12-04

A major cause for diabetic cardiomyopathy is excess lipid accumulation. To elucidate mechanisms of lipotoxicity mediated diabetic heart disease we need to further our understanding of how lipid metabolism is altered in the diabetic heart. Here we investigated the role of lipid clearance by oxidation as a regulator of lipid-mediated toxicity (lipotoxicity). We evaluated the effect of pre-treating rat neonatal cardiomyocytes (NCMs) with either oleate (mono-unsaturated fatty acid) or palmitate (saturated fatty acid) on fatty acid oxidation (FAO) by measuring {sup 14}C–CO{sub 2} production. We evaluated carnitine palmitoyltransferase (Cpt1b) expression by western blotting and mitochondrial membrane potential by quantitative and qualitative fluorescence analyses using the JC-1 dye. We inhibited the Cpt1b pharmacologically using etomoxir and genetically by knocking down its expression using LentiVector mediated transduction of siRNAs targeting the Cpt1b gene. We found that palmitate had a slower clearance rate from NCMs than oleate, and this was associated with a significant decrease in FAO. This impairment in FAO was not the result of either loss of Cpt1b protein or mitochondrial integrity. Enhancing FAO with either oleate or carnitine was associated with a significant attenuation of palmitate mediated lipotoxicity. In contrast impairing FAO in oleate treated NCMs caused lipotoxicity. Here we demonstrate that a major difference between non-toxic unsaturated fatty acids and toxic saturated fatty acids is there ability to stimulate or inhibit fatty acid oxidation, respectively. This has important implications for diabetic cardiomyopathy since diabetic hearts consistently exhibit elevated lipid accumulation. - Highlights: • Palmitate had a slower clearance rate from NCMs than oleate. • Palmitate caused a significant decrease in fatty acid oxidation in cardiomyocytes. • Impaired FAO was not due to loss of Cpt1b protein or mitochondrial integrity. • Enhancing FAO

Impaired fatty acid oxidation as a cause for lipotoxicity in cardiomyocytes

International Nuclear Information System (INIS)

Haffar, T.; Bérubé-Simard, F.; Bousette, N.

2015-01-01

A major cause for diabetic cardiomyopathy is excess lipid accumulation. To elucidate mechanisms of lipotoxicity mediated diabetic heart disease we need to further our understanding of how lipid metabolism is altered in the diabetic heart. Here we investigated the role of lipid clearance by oxidation as a regulator of lipid-mediated toxicity (lipotoxicity). We evaluated the effect of pre-treating rat neonatal cardiomyocytes (NCMs) with either oleate (mono-unsaturated fatty acid) or palmitate (saturated fatty acid) on fatty acid oxidation (FAO) by measuring "1"4C–CO_2 production. We evaluated carnitine palmitoyltransferase (Cpt1b) expression by western blotting and mitochondrial membrane potential by quantitative and qualitative fluorescence analyses using the JC-1 dye. We inhibited the Cpt1b pharmacologically using etomoxir and genetically by knocking down its expression using LentiVector mediated transduction of siRNAs targeting the Cpt1b gene. We found that palmitate had a slower clearance rate from NCMs than oleate, and this was associated with a significant decrease in FAO. This impairment in FAO was not the result of either loss of Cpt1b protein or mitochondrial integrity. Enhancing FAO with either oleate or carnitine was associated with a significant attenuation of palmitate mediated lipotoxicity. In contrast impairing FAO in oleate treated NCMs caused lipotoxicity. Here we demonstrate that a major difference between non-toxic unsaturated fatty acids and toxic saturated fatty acids is there ability to stimulate or inhibit fatty acid oxidation, respectively. This has important implications for diabetic cardiomyopathy since diabetic hearts consistently exhibit elevated lipid accumulation. - Highlights: • Palmitate had a slower clearance rate from NCMs than oleate. • Palmitate caused a significant decrease in fatty acid oxidation in cardiomyocytes. • Impaired FAO was not due to loss of Cpt1b protein or mitochondrial integrity. • Enhancing FAO attenuated

In vitro adsorption of oxalic acid and glyoxylic acid onto activated charcoal, resins and hydrous zirconium oxide

NARCIS (Netherlands)

Scholtens, R.; Scholten, J.; de Koning, H. W.; Tijssen, J.; ten Hoopen, H. W.; Olthuis, F. M.; Feijen, J.

1982-01-01

Patients suffering from primary hyperoxaluria show elevated plasma concentrations of oxalic acid and glyoxylic acid. The in vitro adsorption of these compounds into activated charcoal, a series of neutral and ion exchange resins and onto hydrous zirconium oxide has been investigated. Hydrous

Poly(butylene terephthalate) based novel achiral stationary phase investigated under supercritical fluid chromatography conditions.

Science.gov (United States)

Nagai, Kanji; Shibata, Tohru; Shinkura, Satoshi; Ohnishi, Atsushi

2018-05-11

Poly(butylene terephthalate) based novel stationary phase (SP), composed of planar aromatic phenyl group together with ester group monomer units, was designed for supercritical fluid chromatography (SFC) use. As expected from its structure, this phase shows planarity recognition of isomeric aromatics and closely similar compounds. Interestingly, for most analytes, the retention behavior of this SP is significantly distinct from that of the 2-ethylpyridine based SPs which is among the most well-known SFC dedicated phases. Although the poly(butylene terephthalate) is coated on silica gel, the performance of the column did not change by using extended range modifiers such as THF, dichloromethane or ethyl acetate and column robustness was confirmed by cycle durability testing. Copyright © 2018 The Authors. Published by Elsevier B.V. All rights reserved.

Investigation of the direct and indirect electrochemical oxidation of hydrazine in nitric acid medium on platinum

International Nuclear Information System (INIS)

Cames, B.

1997-01-01

In nuclear fuel processing by the PUREX process, the purification of plutonium in nitric acid medium requires the oxidation of Pu(III) to Pu(IV), and of hydrazinium nitrate to nitrogen. The study helped to characterize the electrochemical behavior of the oxidation of hydrazinium nitrate and the reduction of nitric acid to nitrous acid, a compound which can chemically oxidize hydrazinium nitrate and Pu(III). Electro-analytical studies on polycrystalline platinum showed that hydrazine is oxidized in two potential zones, which depend on the surface texture of the platinum anode. Electrolysis in separate compartments, carried out in medium-acid media (2 and 4 mo/l) in the potential zone where these processes take place, showed that, at 0.9 V/ECS, the hydrazine oxidation reactions involved are: a four-electron process (75 %) with nitrogen formation and a one-electron process (25 %) with formation of nitrogen and ammonium ion. By contrast, electrolysis carried out at 0.65 V/ECS (with reactivation of the electrode at - 0.2 V/ECS to remove the poison from the platinum) allowed the selective oxidation of hydrazine to nitrogen by the four-electron reaction. Nitric acid can only be reduced to nitrous acid in the absence of hydrazine. For medium-acid media (≤ 6 mol/l), this reaction takes place at potentials below - 0.2 V/ECS. However, the production rate of nitrous acid (partial order 0 with respect to nitric acid) is very low compared with the values obtained for strongly-acid media (6 to 10 mol/l) at the potential of - 0.1 V/ECS. Note that, in concentrated nitric medium, the selectivity of the reduction reaction is 47 to 85 % for nitrous acid, depending on the nitric acid concentration (6 to 10 mol/l) and the potential imposed (- 0.1 ≤ E ≤ 0.6 V/ECS). A kinetic study helped to determine the hydrazine oxidation rates as a function of the operating conditions. In all cases, the reaction rate is of partial order 0 with respect to hydrazine. These studies accordingly

Lipid oxidation in fish oil enriched mayonnaise : Calcium disodium ethylenediaminetetraacetate, but not gallic acid, strongly inhibited oxidative deterioration

DEFF Research Database (Denmark)

Jacobsen, Charlotte; Hartvigsen, Karsten; Thomsen, Mikael Holm

2001-01-01

The antioxidative effects of gallic acid, EDTA, and extra emulsifier Panodan DATEM TR in mayonnaise enriched with 16% fish oil were investigated. EDTA reduced the formation of free radicals, lipid hydroperoxides, volatiles, and fishy and rancid off-flavors. The antioxidative effect of EDTA...... acid may therefore promote the decomposition of lipid hydroperoxides to volatile oxidation products. Addition of extra emulsifier reduced the lipid hydroperoxide levels but did not influence the level of free radicals or the oxidative flavor deterioration in mayonnaisse; however, it appeared to alter...

Structural insight into molecular mechanism of poly(ethylene terephthalate) degradation

OpenAIRE

Joo, Seongjoon; Cho, In Jin; Seo, Hogyun; Son, Hyeoncheol Francis; Sagong, Hye-Young; Shin, Tae Joo; Choi, So Young; Lee, Sang Yup; Kim, Kyung-Jin

2018-01-01

Plastics, including poly(ethylene terephthalate) (PET), possess many desirable characteristics and thus are widely used in daily life. However, non-biodegradability, once thought to be an advantage offered by plastics, is causing major environmental problem. Recently, a PET-degrading bacterium, Ideonella sakaiensis, was identified and suggested for possible use in degradation and/or recycling of PET. However, the molecular mechanism of PET degradation is not known. Here we report the crystal ...

Orphan drugs in development for long-chain fatty acid oxidation disorders: challenges and progress

Directory of Open Access Journals (Sweden)

Sun A

2015-04-01

Full Text Available Angela Sun, J Lawrence Merritt II Department of Pediatrics, University of Washington, Seattle, WA, USA Abstract: Fatty acid oxidation disorders are inborn errors of metabolism resulting in failure of ß-oxidation within or transport of fatty acids into the mitochondria. The long-chain fatty acid oxidation disorders are characterized by variable presentations ranging from newborn cardiomyopathy, to infantile hypoketotic hypoglycemia resulting from liver involvement, to skeletal myopathy often resulting in rhabdomyolysis in adolescents and adults. Treatments for these long-chain fatty acid oxidation disorders have typically focused upon avoidance of fasting with dietary fat restriction and medium-chain triglyceride supplementation. These treatments have resulted in only a partial response with improvements in hypoglycemia, reduction in frequency of rhabdomyolysis, and improvement in cardiomyopathy with early therapy, but significant risk remains. Recent advances in therapies for long-chain fatty acid oxidation disorders are reviewed in this article. These include sodium D,L-3-hydroxybutyrate, triheptanoin, gene therapy, and bezafibrates. Sodium D,L-3-hydroxybutyrate has shown clinical effect, with improvements in muscle tone, neurological abnormalities, and some cases of cardiomyopathy and leukodystrophy. Triheptanoin has been used as an alternative medium-chain triglyceride in a number of fatty acid oxidation disorders and has shown promising findings in the treatment of cardiomyopathy and hypoglycemia. However, it does not significantly reduce episodes of rhabdomyolysis. Gene therapy has been shown to improve acylcarnitine levels in very-long-chain acyl-coenzyme A dehydrogenase deficiency mouse models, with preservation of glucose levels. Bezafibrates have shown improvements in acylcarnitine concentrations in fibroblast studies, but clinical observations have not demonstrated consistent effects. Together, these treatments have shown some

Impact of acid and oxidative modifications, single or dual, of sorghum starch on biodegradable films.

Science.gov (United States)

Biduski, Bárbara; Silva, Francine Tavares da; Silva, Wyller Max da; Halal, Shanise Lisie de Mello El; Pinto, Vania Zanella; Dias, Alvaro Renato Guerra; Zavareze, Elessandra da Rosa

2017-01-01

The objective of this study was to evaluate the effects of acid and oxidation modifications on sorghum starch, as well as the effect of dual modification of starch on the physical, morphological, mechanical, and barrier properties of biodegradable films. The acid modification was performed with 3% lactic acid and the oxidation was performed with 1.5% active chlorine. For dual modification, the acid modification was performed first, followed by oxidation under the same conditions as above. Both films of the oxidized starches, single and dual, had increased stiffness, providing a higher tensile strength and lower elongation when compared to films based on native and single acid modified starches. However, the dual modification increased the water vapor permeability of the films without changing their solubility. The increase in sorghum starch concentration in the filmogenic solution increased the thickness, water vapor permeability, and elongation of the films. Copyright © 2016. Published by Elsevier Ltd.

Ultra-low Pt decorated PdFe Alloy Nanoparticles for Formic Acid Electro-oxidation

International Nuclear Information System (INIS)

Zhou, Yawei; Du, Chunyu; Han, Guokang; Gao, Yunzhi; Yin, Geping

2016-01-01

Highlights: • A cost-efficient way is used to prepare transition-noble metal alloy nanoparticles. • The Pd 50 Fe 50 /C catalyst shows excellent activity for formic acid oxidation (FAO). • Much activity enhancement of FAO is acquired by ultra-low Pt decorated Pd 50 Fe 50 . • A synergistic mechanism between Pt clusters and PdFe is proposed during the FAO. - Abstract: Palladium (Pd), has demonstrated promising electro-catalytic activity for formic acid oxidation, but suffers from extremely low abundance. Recently alloying with a transition metal has been considered as an effective approach to reducing the loading of Pd and enhancing the activity of Pd-based catalysts simultaneously. Herein, carbon supported PdFe nanoparticles (NPs) are synthesized at room temperature by using sodium borohydride as reducing agent and potassium ferrocyanide as Fe precursor. The Pd 50 Fe 50 alloy sample annealed at 900 °C for 1 h shows the best catalytic activity among Pd x Fe 1-x (x = 0.2, 0.4, 0.5, 0.6, and 0.8) towards formic acid oxidation. To further improve both catalytic activity and stability, the ultra-low Pt (0.09 wt %) decorated Pd 50 Fe 50 NPs (PtPd/PdFe) are prepared via the galvanic replacement reaction. Compared with Pd 50 Fe 50 /C, the PtPd/PdFe/C Exhibits 1.52 times higher catalytic activity and lower onset potential (−0.12 V). The significant enhancements of formic acid oxidation can be attributed to the accelerated dehydrogenation reaction of formic acid by Pt atomic clusters. Moreover, the PtPd/PdFe/C also demonstrates better tolerance to poisons during formic acid oxidation.

Salvianolic acid B Relieves Oxidative Stress in Glucose Absorption ...

African Journals Online (AJOL)

Absorption and Utilization of Mice Fed High-Sugar Diet ... Salvianolic acid B, Blood glucose, Reactive oxygen species, Oxidative stress, Sugar diet. ... protein expression in human aortic smooth ... induced by glucose uptake and metabolism [8].

Preparation of poly(ethylene terephthalate/layered double hydroxide nanocomposites by in-situ polymerization and their thermal property

Directory of Open Access Journals (Sweden)

Q. Jiao

2012-06-01

Full Text Available Terephthalate (TA intercalated layered double hydroxides (LDHs were synthesized using hydroxides as raw materials, and poly(ethylene terephthalate (PET/LDH nanocomposites with different contents of TA intercalated LDHs were prepared by in-situ polymerization. The structure, morphology and thermal property of PET/LDH nanocomposites were investigated. The TA intercalated LDHs were partially exfoliated and well dispersed in PET matrix. The PET/LDH nanocomposites exhibit enhanced thermal stability relative to pure PET, confirmed by the thermogravimetric analysis results. The results of differential scanning calorimetry suggest that LDH nanoparticles could effectively promote the nucleation and crystallization of PET.

Preparation and characterization of polymer blends based on recycled PET and polyester derived by terephthalic acid; Preparacao e caracterizacao de blendas polimericas a base de PET reciclado e poliester derivado do acido tereftalico

Energy Technology Data Exchange (ETDEWEB)

Ohara, L.; Miranda, C.S.; Fiuza, R.P.; Luporini, S.; Carvalho, R.F.; Jose, N.M., E-mail: leandro.ohara@gmail.co [Universidade Federal da Bahia (GECIM/UFBA), Salvador, BA (Brazil). Inst. de Quimica. Grupo de Energia e Ciencias dos Materiais

2010-07-01

Environmentally friendly materials, made from industrial waste, are being increasingly used as a solution to the growing amount of waste generated by society, but also as a cheaper alternative to replace conventional materials for use in construction. In this work were investigated the properties of polymer blends based on recycled PET and a polyester derived from terephthalic acid and glycerin, a co-product of biodiesel. The samples were characterized by XRD, TGA, DSC, FTIR and SEM. The polyester synthesized showed a degradation event near 300 deg C. The blends with higher ratio of PET showed thermal behavior similar to pure PET. The X-ray diffraction showed that the polymer blends are semicrystalline materials. The micrographs presents the presence of a smooth surface, indicating the possibility of miscibility between the arrays. Therefore, the blending makes possible the fabrication of low-cost materials with applications in several areas. (author)

Kinetics and mechanism of the oxidation of formic and oxalic acids ...

Indian Academy of Sciences (India)

Unknown

The organic acids were commercial products of the highest degree of purity .... reaction is not complete even at high concentration of ZnCl2, and that only the ... activation in the oxidation of oxalic acid suggests the involvement of both the ...

Citric acid effects on brain and liver oxidative stress in lipopolysaccharide-treated mice.

Science.gov (United States)

Abdel-Salam, Omar M E; Youness, Eman R; Mohammed, Nadia A; Morsy, Safaa M Youssef; Omara, Enayat A; Sleem, Amany A

2014-05-01

Citric acid is a weak organic acid found in the greatest amounts in citrus fruits. This study examined the effect of citric acid on endotoxin-induced oxidative stress of the brain and liver. Mice were challenged with a single intraperitoneal dose of lipopolysaccharide (LPS; 200 μg/kg). Citric acid was given orally at 1, 2, or 4 g/kg at time of endotoxin injection and mice were euthanized 4 h later. LPS induced oxidative stress in the brain and liver tissue, resulting in marked increase in lipid peroxidation (malondialdehyde [MDA]) and nitrite, while significantly decreasing reduced glutathione, glutathione peroxidase (GPx), and paraoxonase 1 (PON1) activity. Tumor necrosis factor-alpha (TNF-α) showed a pronounced increase in brain tissue after endotoxin injection. The administration of citric acid (1-2 g/kg) attenuated LPS-induced elevations in brain MDA, nitrite, TNF-α, GPx, and PON1 activity. In the liver, nitrite was decreased by 1 g/kg citric acid. GPx activity was increased, while PON1 activity was decreased by citric acid. The LPS-induced liver injury, DNA fragmentation, serum transaminase elevations, caspase-3, and inducible nitric oxide synthase expression were attenuated by 1-2 g/kg citric acid. DNA fragmentation, however, increased after 4 g/kg citric acid. Thus in this model of systemic inflammation, citric acid (1-2 g/kg) decreased brain lipid peroxidation and inflammation, liver damage, and DNA fragmentation.

Spectrophotometric and potentiometric studies of oxidation of Mo(III) by Mo(VI) in phosphoric acid medium

Energy Technology Data Exchange (ETDEWEB)

Kumar, A; Verma, G S.P. [Ranchi Coll. (India). Dept. of Chemistry

1975-12-01

Oxidation of Mo(III) (green) by Mo(VI) in an inert atmosphere and in orthophosphoric acid medium at various acid concentrations is reported. Potentiometric and spectrophotometric data suggest that oxidation of Mo(III) proceeds to Mo(V) through a binuclear species Mo(III) Mo(IV) absorbing at 400 nm. The formation of this species is facilitated at high acid concentrations. It is further found that quantitative conversion of Mo(III) into Mo(V) takes place at fairly high acid concentrations. In high phosphoric acid concentrations, solution of Mo(III) has been found to be oxidized to Mo(VI) by air and hence this can be used as a good oxygen absorber.

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...

Oxalic acid induced hydrothermal synthesis of single crystalline tungsten oxide nanorods

International Nuclear Information System (INIS)

Patil, V.B.; Adhyapak, P.V.; Suryavanshi, S.S.; Mulla, I.S.

2014-01-01

Highlights: • We report synthesis of 1D tungsten oxide using a hydrothermal route at 170 °C. • Oxalic acid plays an important role in the formation of 1D nanostructure. • Monoclinic transforms to hexagonal phase with increment in reaction duration. -- Abstract: One-dimensional single-crystalline tungsten oxide nanorods have been synthesized by the hydrothermal technique. The controlled morphology of tungsten oxide was obtained by using sodium tungstate and oxalic acid as an organic inducer. The reaction was carried out at 170 °C for 24, 48 and 72 h. The obtained tungsten oxides were investigated by using XRD, SEM and HRTEM techniques. In order to understand the role of organic inducer on the shape, size and phase formation of WO 3 was prepared with and without organic inducer. On heating of sodium tungstate without organic inducer for 72 h at 170 °C in the hydrothermal unit we obtain nanoparticles of monoclinic WO 3 , however, on addition of oxalic acid a single phase hexagonal WO 3 with distinct nanorods was formed. On addition of oxalic acid a systematic emergence of nanorod-like morphology was obtained with incrementing reaction times from 24 h to 48 h. The 72 h reaction generates self-assembled 20–30 nm diameter and 4–5 μm long h-WO 3 bundles of nanorods. The XRD studies show hexagonal structure of tungsten oxide, while SAED reveals its single crystalline nature. The photoluminescence (PL) emission spectrum shows a characteristic blue emission peak at 3 eV (410 nm). Raman spectra provide the evidence of hexagonal structure with stretching vibrations (830 cm −1 ) for 72 h of heating at 170 °C

Oxalic acid induced hydrothermal synthesis of single crystalline tungsten oxide nanorods

Energy Technology Data Exchange (ETDEWEB)

Patil, V.B. [School of Physical Sciences, Solapur University, Solapur 413255 (India); Adhyapak, P.V. [Centre for Materials for Electronic Technology (C-MET), Pune 411008 (India); Suryavanshi, S.S., E-mail: sssuryavanshi@rediffmail.com [School of Physical Sciences, Solapur University, Solapur 413255 (India); Mulla, I.S., E-mail: ismulla2001@gmail.com [Emeritus Scientist (CSIR), Centre for Materials for Electronic Technology (C-MET), Pune 411008 (India)

2014-03-25

Highlights: • We report synthesis of 1D tungsten oxide using a hydrothermal route at 170 °C. • Oxalic acid plays an important role in the formation of 1D nanostructure. • Monoclinic transforms to hexagonal phase with increment in reaction duration. -- Abstract: One-dimensional single-crystalline tungsten oxide nanorods have been synthesized by the hydrothermal technique. The controlled morphology of tungsten oxide was obtained by using sodium tungstate and oxalic acid as an organic inducer. The reaction was carried out at 170 °C for 24, 48 and 72 h. The obtained tungsten oxides were investigated by using XRD, SEM and HRTEM techniques. In order to understand the role of organic inducer on the shape, size and phase formation of WO{sub 3} was prepared with and without organic inducer. On heating of sodium tungstate without organic inducer for 72 h at 170 °C in the hydrothermal unit we obtain nanoparticles of monoclinic WO{sub 3}, however, on addition of oxalic acid a single phase hexagonal WO{sub 3} with distinct nanorods was formed. On addition of oxalic acid a systematic emergence of nanorod-like morphology was obtained with incrementing reaction times from 24 h to 48 h. The 72 h reaction generates self-assembled 20–30 nm diameter and 4–5 μm long h-WO{sub 3} bundles of nanorods. The XRD studies show hexagonal structure of tungsten oxide, while SAED reveals its single crystalline nature. The photoluminescence (PL) emission spectrum shows a characteristic blue emission peak at 3 eV (410 nm). Raman spectra provide the evidence of hexagonal structure with stretching vibrations (830 cm{sup −1}) for 72 h of heating at 170 °C.

Primary oxidation and reduction products in x-irradiated aspartic acid

International Nuclear Information System (INIS)

Adams, S.M.; Budzinski, E.E.; Box, H.C.

1976-01-01

The primary reduction products identified by ESR--ENDOR spectroscopy in single crystals of DL-aspartic acid hydrochloride irradiated at 4.2degreeK are anions formed by addition of an electron to the carbonyl oxygen atoms of the carboxylic acid groups. The main consequence of the oxidation process is to produce a hole centered mainly on atomic chlorine

Ultra-low power thin film transistors with gate oxide formed by nitric acid oxidation method

International Nuclear Information System (INIS)

Kobayashi, H.; Kim, W. B.; Matsumoto, T.

2011-01-01

We have developed a low temperature fabrication method of SiO 2 /Si structure by use of nitric acid, i.e., nitric acid oxidation of Si (NAOS) method, and applied it to thin film transistors (TFT). A silicon dioxide (SiO 2 ) layer formed by the NAOS method at room temperature possesses 1.8 nm thickness, and its leakage current density is as low as that of thermally grown SiO 2 layer with the same thickness formed at ∼900 deg C. The fabricated TFTs possess an ultra-thin NAOS SiO 2 /CVD SiO 2 stack gate dielectric structure. The ultrathin NAOS SiO 2 layer effectively blocks a gate leakage current, and thus, the thickness of the gate oxide layer can be decreased from 80 to 20 nm. The thin gate oxide layer enables to decrease the operation voltage to 2 V (cf. the conventional operation voltage of TFTs with 80 nm gate oxide: 12 V) because of the low threshold voltages, i.e., -0.5 V for P-ch TFTs and 0.5 V for N-ch TFTs, and thus the consumed power decreases to 1/36 of that of the conventional TFTs. The drain current increases rapidly with the gate voltage, and the sub-threshold voltage is ∼80 mV/dec. The low sub-threshold swing is attributable to the thin gate oxide thickness and low interface state density of the NAOS SiO 2 layer. (authors)

Potentiometric studies of acid-base interactions in substituted 4-nitropyridine N-oxide systems

International Nuclear Information System (INIS)

Gurzynski, Lukasz; Puszko, Aniela; Ostrzechowska, Agnieszka; Makowski, Mariusz; Chmurzynski, Lech

2006-01-01

(Acid+base) equilibrium constants, involving the acidity (pK a AC ) and cationic homoconjugation constants (in the form of lgK BHB + AC ), have been determined by the potentiometric method in 13 systems formed by substituted 4-nitropyridine N-oxides in the polar aprotic solvent, acetone (AC). The derivatives covered a wide range of proton-acceptor properties and inherent diversified tendencies towards formation of hydrogen-bonded homocomplexed cations. In addition, the constant values (expressed as pK a AN andlgK BHB + AN ) for two of the systems studied, N-oxides of 2-methylamino- and 2-ethylamino-4-nitropyridine, were determined in acetonitrile (AN). The acidity constants in the non-aqueous media studied have been found to change in line with their substituent effects and the sequence of acidity changes in water. The values of the cationic homoconjugation constants increased with increasing basicity of the N-oxides and decreased with increasing solvent basicity

Potentiometric studies of acid-base interactions in substituted 4-nitropyridine N-oxide systems

Energy Technology Data Exchange (ETDEWEB)

Gurzynski, Lukasz [Department of General Chemistry, University of Gdansk, Sobieskiego 18, 80-952 Gdansk (Poland); Puszko, Aniela [Department of Organic Chemistry, School of Economics, Wroclaw (Poland); Ostrzechowska, Agnieszka [Department of General Chemistry, University of Gdansk, Sobieskiego 18, 80-952 Gdansk (Poland); Makowski, Mariusz [Department of General Chemistry, University of Gdansk, Sobieskiego 18, 80-952 Gdansk (Poland); Chmurzynski, Lech [Department of General Chemistry, University of Gdansk, Sobieskiego 18, 80-952 Gdansk (Poland)]. E-mail: lech@chem.univ.gda.pl

2006-05-15

(Acid+base) equilibrium constants, involving the acidity (pK{sub a}{sup AC}) and cationic homoconjugation constants (in the form of lgK{sub BHB{sup +}}{sup AC}), have been determined by the potentiometric method in 13 systems formed by substituted 4-nitropyridine N-oxides in the polar aprotic solvent, acetone (AC). The derivatives covered a wide range of proton-acceptor properties and inherent diversified tendencies towards formation of hydrogen-bonded homocomplexed cations. In addition, the constant values (expressed as pK{sub a}{sup AN}andlgK{sub BHB{sup +}}{sup AN}) for two of the systems studied, N-oxides of 2-methylamino- and 2-ethylamino-4-nitropyridine, were determined in acetonitrile (AN). The acidity constants in the non-aqueous media studied have been found to change in line with their substituent effects and the sequence of acidity changes in water. The values of the cationic homoconjugation constants increased with increasing basicity of the N-oxides and decreased with increasing solvent basicity.

Critical evaluation of pressurized microwave-assisted digestion efficiency using nitric acid oxidizing systems (M7)

International Nuclear Information System (INIS)

Matusiewicz, H.

2002-01-01

Full text: The possibilities of enhancement of a medium-pressure microwave-assisted digestion system for sample preparation in trace element analysis of biological material was investigated. Based on optimal digestion conditions for oxidizing systems with nitric acid, different digestion procedures were examined to minimize residual carbon. The substitution of nitric acid and the addition of hydrogen peroxide and ozone to nitric acid was evaluated. The residual carbon content of the digestate was determined coulometrically. Addition of hydrogen peroxide during organic oxidation reactions does not lower the resolved carbon in the solution. Ozone was tested as an additional, potentially non-contaminating, digestion/oxidation system to the nitric acid used in the sample preparation method. (author)

CPT1α over-expression increases long-chain fatty acid oxidation and reduces cell viability with incremental palmitic acid concentration in 293T cells

International Nuclear Information System (INIS)

Jambor de Sousa, Ulrike L.; Koss, Michael D.; Fillies, Marion; Gahl, Anja; Scheeder, Martin R.L.; Cardoso, M. Cristina; Leonhardt, Heinrich; Geary, Nori; Langhans, Wolfgang; Leonhardt, Monika

2005-01-01

To test the cellular response to an increased fatty acid oxidation, we generated a vector for an inducible expression of the rate-limiting enzyme carnitine palmitoyl-transferase 1α (CPT1α). Human embryonic 293T kidney cells were transiently transfected and expression of the CPT1α transgene in the tet-on vector was activated with doxycycline. Fatty acid oxidation was measured by determining the conversion of supplemented, synthetic cis-10-heptadecenoic acid (C17:1n-7) to C15:ln-7. CPT1α over-expression increased mitochondrial long-chain fatty acid oxidation about 6-fold. Addition of palmitic acid (PA) decreased viability of CPT1α over-expressing cells in a concentration-dependent manner. Both, PA and CPT1α over-expression increased cell death. Interestingly, PA reduced total cell number only in cells over-expressing CPT1α, suggesting an effect on cell proliferation that requires PA translocation across the mitochondrial inner membrane. This inducible expression system should be well suited to study the roles of CPT1 and fatty acid oxidation in lipotoxicity and metabolism in vivo

Interactions of benzoic acid and phosphates with iron oxide colloids using chemical force titration.

Science.gov (United States)

Liang, Jana; Horton, J Hugh

2005-11-08

Colloidal iron oxides are an important component in soil systems and in water treatment processes. Humic-based organic compounds, containing both phenol and benzoate functional groups, are often present in these systems and compete strongly with phosphate species for binding sites on the iron oxide surfaces. Here, we examine the interaction of benzoate and phenolic groups with various iron oxide colloids using atomic force microscopy (AFM) chemical force titration measurements. Self-assembled monolayers (SAMs) of 4-(12-mercaptododecyloxy)benzoic acid and 4-(12-mercaptododecyloxy)phenol were used to prepare chemically modified Au-coated AFM tips, and these were used to probe the surface chemistry of a series of iron oxide colloids. The SAMs formed were also characterized using scanning tunneling microscopy, reflection-absorption infrared spectroscopy, and X-ray photoelectron spectroscopy. The surface pK(a) of 4-(12- mercaptododecyloxy)benzoic acid has been determined to be 4.0 +/- 0.5, and the interaction between the tip and the sample coated with a SAM of this species is dominated by hydrogen bonding. The chemical force titraton profile for an AFM probe coated with 4-(12- mercaptododecyloxy)benzoic acid and a bare iron oxide colloid demonstrates that the benzoic acid function group interacts with all three types of iron oxide sites present on the colloid surface over a wide pH range. Similar experiments were carried out on colloids precipitated in the presence of phosphoric, gallic, and tannic acids. The results are discussed in the context of the competitive binding interactions of solution species present in soils or in water treatment processes.

HPLC-ESI-MS/MS analysis of oxidized di-caffeoylquinic acids generated by metalloporphyrin-catalyzed reactions

International Nuclear Information System (INIS)

Santos, Michel D.; Lopes, Norberto P.; Iamamoto, Yassuko

2008-01-01

This paper reports an HPLC-ESI-MS/MS investigation on the oxidation of 3,5- and 4,5- dicaffeoylquinic acid using iron(III) tetraphenylporphyrin chloride as catalyst. Two major mono-oxidised products of the quinic acid moiety have been identified for both compounds. However, only the 4,5-derivative afforded two different tri-oxo products. Thus, it seems that the oxidation pattern depends on the number and positions of the caffeic acid moieties present in caffeoylquinic acid molecules. (author)

HPLC-ESI-MS/MS analysis of oxidized di-caffeoylquinic acids generated by metalloporphyrin-catalyzed reactions

Energy Technology Data Exchange (ETDEWEB)

Santos, Michel D.; Lopes, Norberto P. [Universidade de Sao Paulo (USP), Ribeirao Preto, SP (Brazil). Faculdade de Ciencias Farmaceuticas. Dept. de Fisica e Quimica]. E-mail: npelopes@fcfrp.usp.br; Iamamoto, Yassuko [Universidade de Sao Paulo (USP), Ribeirao Preto, SP (Brazil). Faculdade de Ciencias Farmaceuticas. Dept. de Quimica

2008-07-01

This paper reports an HPLC-ESI-MS/MS investigation on the oxidation of 3,5- and 4,5- dicaffeoylquinic acid using iron(III) tetraphenylporphyrin chloride as catalyst. Two major mono-oxidised products of the quinic acid moiety have been identified for both compounds. However, only the 4,5-derivative afforded two different tri-oxo products. Thus, it seems that the oxidation pattern depends on the number and positions of the caffeic acid moieties present in caffeoylquinic acid molecules. (author)

Investigation of Influential Parameters in Deep Oxidative Desulfurization of Dibenzothiophene with Hydrogen Peroxide and Formic Acid

OpenAIRE

Haghighat Mamaghani, Alireza; Fatemi, Shohreh; Asgari, Mehrdad

2013-01-01

An effective oxidative system consisting of hydrogen peroxide, formic acid, and sulfuric acid followed by an extractive stage were implemented to remove dibenzothiophene in the simulated fuel oil. The results revealed such a great performance in the case of H2O2 in the presence of formic and sulfuric acids that led to the removal of sulfur compounds. Sulfuric acid was employed to increase the acidity of media as well as catalytic activity together with formic acid. The oxidation reaction was ...

Assays for urinary biomarkers of oxidatively damaged nucleic acids

DEFF Research Database (Denmark)

Weimann, Allan; Broedbaek, Kasper; Henriksen, Trine

2012-01-01

Abstract The analysis of oxidized nucleic acid metabolites can be performed by a variety of methodologies: liquid chromatography coupled with electrochemical or mass-spectrometry detection, gas chromatography coupled with mass spectrometry, capillary electrophoresis and ELISA (Enzyme-linked immun...

Spectrophotometric and potentiometric studies of oxidation of Mo(III) by Mo(VI) in phosphoric acid medium

International Nuclear Information System (INIS)

Kumar, Arvind; Verma, G.S.P.

1975-01-01

Oxidation of Mo(III) (green) by Mo(VI) in an inert atmosphere and in orthophosphoric acid medium at various acid concentrations is reported. Potentiometric and spectrophotometric data suggest that oxidation of Mo(III) proceeds to Mo(V) through a binuclear species Mo(III) Mo(IV) absorbing at 400 nm. The formation of this species is facilitated at high acid concentrations. It is further found that quantitative conversion of Mo(III) into Mo(V) takes place at fairly high acid concentrations. In high phosphoric acid concentrations, solution of Mo(III) has been found to be oxidized to Mo(VI) by air and hence this can be used as a good oxygen absorber. (author)

10-Oxo-trans-11-octadecenoic acid generated from linoleic acid by a gut lactic acid bacterium Lactobacillus plantarum is cytoprotective against oxidative stress

Energy Technology Data Exchange (ETDEWEB)

Furumoto, Hidehiro; Nanthirudjanar, Tharnath [Division of Applied Biosciences, Graduate School of Agriculture, Kyoto University, Kitashirakawa Oiwake-cho, Sakyo-ku, Kyoto 606-8502 (Japan); Kume, Toshiaki; Izumi, Yasuhiko [Department of Pharmacology, Graduate School of Pharmaceutical Sciences, Kyoto University, 46-29, Simoadachi-cho, Sakyo-ku, Kyoto 606-8501 (Japan); Park, Si-Bum [Laboratory of Industrial Microbiology, Graduate School of Agriculture, Kyoto University, Kitashirakawa Oiwake-cho, Sakyo-ku, Kyoto 606-8502 (Japan); Kitamura, Nahoko; Kishino, Shigenobu; Ogawa, Jun [Division of Applied Life Sciences, Graduate School of Agriculture, Kyoto University, Kitashirakawa Oiwake-cho, Sakyo-ku, Kyoto 606-8502 (Japan); Hirata, Takashi [Division of Applied Biosciences, Graduate School of Agriculture, Kyoto University, Kitashirakawa Oiwake-cho, Sakyo-ku, Kyoto 606-8502 (Japan); Faculty of Rehabilitation, Shijonawategakuen University, 5-11-10, Hojo, Daitou-shi, Osaka 574-0011 (Japan); Sugawara, Tatsuya, E-mail: sugawara@kais.kyoto-u.ac.jp [Division of Applied Biosciences, Graduate School of Agriculture, Kyoto University, Kitashirakawa Oiwake-cho, Sakyo-ku, Kyoto 606-8502 (Japan)

2016-04-01

Oxidative stress is a well-known cause of multiple diseases. The nuclear factor erythroid 2-related factor 2 (Nrf2)-antioxidant response element (ARE) pathway plays a central role in cellular antioxidative responses. In this study, we investigated the effects of novel fatty acid metabolite derivatives of linoleic acid generated by the gut lactic acid bacteria Lactobacillus plantarum on the Nrf2-ARE pathway. 10-Oxo-trans-11-octadecenoic acid (KetoC) protected HepG2 cells from cytotoxicity induced by hydrogen peroxide. KetoC also significantly increased cellular Nrf2 protein levels, ARE-dependent transcription, and the gene expression of antioxidative enzymes such as heme oxygenase-1 (HO-1), glutamate-cysteine ligase modifier subunit (GCLM), and NAD(P)H:quinone oxidoreductase 1 (NQO1) in HepG2 cells. Additionally, a single oral dose administration of KetoC also increased antioxidative gene expression and protein levels of Nrf2 and HO-1 in mouse organs. Since other fatty acid metabolites and linoleic acid did not affect cellular antioxidative responses, the cytoprotective effect of KetoC may be because of its α,β-unsaturated carbonyl moiety. Collectively, our data suggested that KetoC activated the Nrf2-ARE pathway to enhance cellular antioxidative responses in vitro and in vivo, which further suggests that KetoC may prevent multiple diseases induced by oxidative stress. - Highlights: • We evaluated the effect of modified fatty acids generated by Lactobacillus plantarum. • 10-Oxo-trans-11-ocatadecenoic acid (KetoC) protected cells from oxidative stress. • KetoC activated the Nrf2-ARE pathway to promote antioxidative gene expression. • KetoC promoted the expression of antioxidative enzymes in mice organs. • The cytoprotective effect of KetoC was because of α,β-unsaturated carbonyl moiety.

10-Oxo-trans-11-octadecenoic acid generated from linoleic acid by a gut lactic acid bacterium Lactobacillus plantarum is cytoprotective against oxidative stress

International Nuclear Information System (INIS)

Furumoto, Hidehiro; Nanthirudjanar, Tharnath; Kume, Toshiaki; Izumi, Yasuhiko; Park, Si-Bum; Kitamura, Nahoko; Kishino, Shigenobu; Ogawa, Jun; Hirata, Takashi; Sugawara, Tatsuya

2016-01-01

Oxidative stress is a well-known cause of multiple diseases. The nuclear factor erythroid 2-related factor 2 (Nrf2)-antioxidant response element (ARE) pathway plays a central role in cellular antioxidative responses. In this study, we investigated the effects of novel fatty acid metabolite derivatives of linoleic acid generated by the gut lactic acid bacteria Lactobacillus plantarum on the Nrf2-ARE pathway. 10-Oxo-trans-11-octadecenoic acid (KetoC) protected HepG2 cells from cytotoxicity induced by hydrogen peroxide. KetoC also significantly increased cellular Nrf2 protein levels, ARE-dependent transcription, and the gene expression of antioxidative enzymes such as heme oxygenase-1 (HO-1), glutamate-cysteine ligase modifier subunit (GCLM), and NAD(P)H:quinone oxidoreductase 1 (NQO1) in HepG2 cells. Additionally, a single oral dose administration of KetoC also increased antioxidative gene expression and protein levels of Nrf2 and HO-1 in mouse organs. Since other fatty acid metabolites and linoleic acid did not affect cellular antioxidative responses, the cytoprotective effect of KetoC may be because of its α,β-unsaturated carbonyl moiety. Collectively, our data suggested that KetoC activated the Nrf2-ARE pathway to enhance cellular antioxidative responses in vitro and in vivo, which further suggests that KetoC may prevent multiple diseases induced by oxidative stress. - Highlights: • We evaluated the effect of modified fatty acids generated by Lactobacillus plantarum. • 10-Oxo-trans-11-ocatadecenoic acid (KetoC) protected cells from oxidative stress. • KetoC activated the Nrf2-ARE pathway to promote antioxidative gene expression. • KetoC promoted the expression of antioxidative enzymes in mice organs. • The cytoprotective effect of KetoC was because of α,β-unsaturated carbonyl moiety.

Growth behavior of anodic oxide formed by aluminum anodizing in glutaric and its derivative acid electrolytes

Science.gov (United States)

Nakajima, Daiki; Kikuchi, Tatsuya; Natsui, Shungo; Suzuki, Ryosuke O.

2014-12-01

The growth behavior of anodic oxide films formed via anodizing in glutaric and its derivative acid solutions was investigated based on the acid dissociation constants of electrolytes. High-purity aluminum foils were anodized in glutaric, ketoglutaric, and acetonedicarboxylic acid solutions under various electrochemical conditions. A thin barrier anodic oxide film grew uniformly on the aluminum substrate by glutaric acid anodizing, and further anodizing caused the film to breakdown due to a high electric field. In contrast, an anodic porous alumina film with a submicrometer-scale cell diameter was successfully formed by ketoglutaric acid anodizing at 293 K. However, the increase and decrease in the temperature of the ketoglutaric acid resulted in non-uniform oxide growth and localized pitting corrosion of the aluminum substrate. An anodic porous alumina film could also be fabricated by acetonedicarboxylic acid anodizing due to the relatively low dissociation constants associated with the acid. Acid dissociation constants are an important factor for the fabrication of anodic porous alumina films.

Surface characterization of polyethylene terephthalate films treated by ammonia low-temperature plasma

International Nuclear Information System (INIS)

Zheng Zhiwen; Ren Li; Feng Wenjiang; Zhai Zhichen; Wang Yingjun

2012-01-01

In order to study the surface characterization and protein adhesion behavior of polyethylene terephthalate film, low temperature ammonia plasma was used to modify the film. Effects of plasma conditions of the surface structures and properties were investigated. Results indicated that surface hydrophilicity of polyethylene terephthalate was significantly improved by ammonia plasma treatment. Ammonia plasma played the role more important than air treatment in the process of modification. Furthermore, by Fourier Transform Infrared spectra some new bonds such as -N=O and N-H which could result in the improvement of the surface hydrophilicity were successfully grafted on the film surface. Atom force microscope experiments indicated that more protein adsorbed on hydrophobic surfaces than hydrophilic ones, and the blobs arranged in a straight line at etching surface by plasma. Modified membrane after ammonia plasma treatment had a good cell affinity and could be effective in promoting the adhesion and growth of cells on the material surface. Timeliness experiments showed that the plasma treatment gave the material a certain performance only in a short period of time and the hydrophobicity recovered after 12 days.

Recovery of iron oxides from acid mine drainage and their application as adsorbent or catalyst.

Science.gov (United States)

Flores, Rubia Gomes; Andersen, Silvia Layara Floriani; Maia, Leonardo Kenji Komay; José, Humberto Jorge; Moreira, Regina de Fatima Peralta Muniz

2012-11-30

Iron oxide particles recovered from acid mine drainage represent a potential low-cost feedstock to replace reagent-grade chemicals in the production of goethite, ferrihydrite or magnetite with relatively high purity. Also, the properties of iron oxides recovered from acid mine drainage mean that they can be exploited as catalysts and/or adsorbents to remove azo dyes from aqueous solutions. The main aim of this study was to recover iron oxides with relatively high purity from acid mine drainage to act as a catalyst in the oxidation of dye through a Fenton-like mechanism or as an adsorbent to remove dyes from an aqueous solution. Iron oxides (goethite) were recovered from acid mine drainage through a sequential precipitation method. Thermal treatment at temperatures higher than 300 °C produces hematite through a decrease in the BET area and an increase in the point of zero charge. In the absence of hydrogen peroxide, the solids adsorbed the textile dye Procion Red H-E7B according to the Langmuir model, and the maximum amount adsorbed decreased as the temperature of the thermal treatment increased. The decomposition kinetics of hydrogen peroxide is dependent on the H(2)O(2) concentration and iron oxides dosage, but the second-order rate constant normalized to the BET surface area is similar to that for different iron oxides tested in this and others studies. These results indicate that acid mine drainage could be used as a source material for the production of iron oxide catalysts/adsorbents, with comparable quality to those produced using analytical-grade reagents. Copyright © 2012 Elsevier Ltd. All rights reserved.

Mitochondrial dysfunction in fatty acid oxidation disorders: insights from human and animal studies

OpenAIRE

Wajner, Moacir; Amaral, Alexandre?Umpierrez

2016-01-01

Mitochondrial fatty acid oxidation (FAO) plays a pivotal role in maintaining body energy homoeostasis mainly during catabolic states. Oxidation of fatty acids requires approximately 25 proteins. Inherited defects of FAO have been identified in the majority of these proteins and constitute an important group of inborn errors of metabolism. Affected patients usually present with severe hepatopathy, cardiomyopathy and skeletal myopathy, whereas some patients may suffer acute and/or progressive e...

Comment on "A bacterium that degrades and assimilates poly(ethylene terephthalate)".

Science.gov (United States)

Yang, Yu; Yang, Jun; Jiang, Lei

2016-08-19

Yoshida et al (Report, 11 March 2016, p. 1196) reported that the bacterium Ideonella sakaiensis 201-F6 can degrade and assimilate poly(ethylene terephthalate) (PET). However, the authors exaggerated degradation efficiency using a low-crystallinity PET and presented no straightforward experiments to verify depolymerization and assimilation of PET. Thus, the authors' conclusions are rather misleading. Copyright © 2016, American Association for the Advancement of Science.

The effects of solvents and structure on the electronic absorption spectra of the isomeric pyridine carboxylic acid N-oxides

Directory of Open Access Journals (Sweden)

Drmanić Saša Ž.

2013-01-01

Full Text Available The ultraviolet absorption spectra of the carboxyl group of three isomeric pyridine carboxylic acids N-oxides (picolinic acid N-oxide, nicotinic acid N-oxide and isonicotinic acid N-oxide were determined in fourteen solvents in the wavelength range from 200 to 400 nm. The position of the absorption maxima (λmax of the examined acids showed that the ultraviolet absorption maximum wavelengths of picolinic acid N-oxide are the shortest, and those of isonicotinic acid N-oxide acid are the longest. In order to analyze the solvent effect on the obtained absorption spectra, the ultraviolet absorption frequencies of the electronic transitions in the carboxylic group of the examined acids were correlated using a total solvatochromic equation of the form max = v0 + sπ + aα+ bβ, where υmax is the absorption frequency (1/λmax, p is a measure of the solvent polarity, β represents the scale of solvent hydrogen bond acceptor basicities and α represent the scale of solvent hydrogen bond donor acidities. The correlation of the spectroscopic data was carried out by means of multiple linear regression analysis. The solvent effects on the ultraviolet absorption maximums of the examined acids were discussed.

Properties of nanocellulose isolated from corncob residue using sulfuric acid, formic acid, oxidative and mechanical methods.

Science.gov (United States)

Liu, Chao; Li, Bin; Du, Haishun; Lv, Dong; Zhang, Yuedong; Yu, Guang; Mu, Xindong; Peng, Hui

2016-10-20

In this work, nanocellulose was extracted from bleached corncob residue (CCR), an underutilized lignocellulose waste from furfural industry, using four different methods (i.e. sulfuric acid hydrolysis, formic acid (FA) hydrolysis, 2,2,6,6-tetramethylpiperidine-1-oxyl (TEMPO)-mediated oxidation, and pulp refining, respectively). The self-assembled structure, morphology, dimension, crystallinity, chemical structure and thermal stability of prepared nanocellulose were investigated. FA hydrolysis produced longer cellulose nanocrystals (CNCs) than the one obtained by sulfuric acid hydrolysis, and resulted in high crystallinity and thermal stability due to its preferential degradation of amorphous cellulose and lignin. The cellulose nanofibrils (CNFs) with fine and individualized structure could be isolated by TEMPO-mediated oxidation. In comparison with other nanocellulose products, the intensive pulp refining led to the CNFs with the longest length and the thickest diameter. This comparative study can help to provide an insight into the utilization of CCR as a potential source for nanocellulose production. Copyright © 2016 Elsevier Ltd. All rights reserved.

Influence of Catalyst Acid/Base Properties in Acrolein Production by Oxidative Coupling of Ethanol and Methanol.

Science.gov (United States)

Lilić, Aleksandra; Bennici, Simona; Devaux, Jean-François; Dubois, Jean-Luc; Auroux, Aline

2017-05-09

Oxidative coupling of methanol and ethanol represents a new route to produce acrolein. In this work, the overall reaction was decoupled in two steps, the oxidation and the aldolization, by using two consecutive reactors to investigate the role of the acid/base properties of silica-supported oxide catalysts. The oxidation of a mixture of methanol and ethanol to formaldehyde and acetaldehyde was performed over a FeMoO x catalyst, and then the product mixture was transferred without intermediate separation to a second reactor, in which the aldol condensation and dehydration to acrolein were performed over the supported oxides. The impact of the acid/base properties on the selectivity towards acrolein was investigated under oxidizing conditions for the first time. The acid/base properties of the catalysts were investigated by NH 3 -, SO 2 -, and methanol-adsorption microcalorimetry. A MgO/SiO 2 catalyst was the most active in acrolein production owing to an appropriate ratio of basic to acidic sites. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

HPLC-ESI-MS/MS analysis of oxidized di-caffeoylquinic acids generated by metalloporphyrin-catalyzed reactions

Directory of Open Access Journals (Sweden)

Michel D. Santos

2008-01-01

Full Text Available This paper reports an HPLC-ESI-MS/MS investigation on the oxidation of 3,5- and 4,5- dicaffeoylquinic acid using iron(III tetraphenylporphyrin chloride as catalyst. Two major mono-oxidised products of the quinic acid moiety have been identified for both compounds. However, only the 4,5-derivative afforded two different tri-oxo products. Thus, it seems that the oxidation pattern depends on the number and positions of the caffeic acid moieties present in caffeoylquinic acid molecules.

Quantification of Radicals Generated in a Sonicator

Directory of Open Access Journals (Sweden)

Kassim Badmus

2016-06-01

Full Text Available The hydroxyl radical (OH• is a powerful oxidant produced as a consequence of cavitation in water. It can react nonspecifically in breaking down persistent organic pollutants in water into their mineral form. It can also recombine to form hydrogen peroxide which is very useful in water treatment. In this study, terephthalic acid (TA and potassium iodide dosimetry were used to quantify and investigate the behaviour of the generated OH radical in a laboratory scale sonicator. The 2-hydroxyl terephthalic acid (HTA formed during terephthalic acid dosimetry was determined by optical fibre spectrometer. The production rate of HTA served as a means of evaluating and characterizing the OH• generated over given time in a sonicator. The influence of sonicator power intensity, solution pH and irradiation time upon OH• generation were investigated. Approximately 2.2 ´ 10-9 M s-1 of OH radical was generated during the sonication process. The rate of generation of the OH radicals was established to be independent of the concentration of the initial reactant. Thus, the rate of generation of OH• can be predicted by zero order kinetics in a sonicator.

Electronic [UV-Visible] and vibrational [FT-IR, FT-Raman] investigation and NMR-mass spectroscopic analysis of terephthalic acid using quantum Gaussian calculations

Science.gov (United States)

Karthikeyan, N.; Joseph Prince, J.; Ramalingam, S.; Periandy, S.

2015-03-01

In this research work, the vibrational IR, polarization Raman, NMR and mass spectra of terephthalic acid (TA) were recorded. The observed fundamental peaks (IR, Raman) were assigned according to their distinctiveness region. The hybrid computational calculations were carried out for calculating geometrical and vibrational parameters by DFT (B3LYP and B3PW91) methods with 6-31++G(d,p) and 6-311++G(d,p) basis sets and the corresponding results were tabulated. The molecular mass spectral data related to base molecule and substitutional group of the compound was analyzed. The modification of the chemical property by the reaction mechanism of the injection of dicarboxylic group in the base molecule was investigated. The 13C and 1H NMR spectra were simulated by using the gauge independent atomic orbital (GIAO) method and the absolute chemical shifts related to TMS were compared with experimental spectra. The study on the electronic and optical properties; absorption wavelengths, excitation energy, dipole moment and frontier molecular orbital energies, were performed by hybrid Gaussian calculation methods. The orbital energies of different levels of HOMO and LUMO were calculated and the molecular orbital lobe overlapping showed the inter charge transformation between the base molecule and ligand group. From the frontier molecular orbitals (FMO), the possibility of electrophilic and nucleophilic hit also analyzed. The NLO activity of the title compound related to Polarizability and hyperpolarizability were also discussed. The present molecule was fragmented with respect to atomic mass and the mass variation depends on the substitutions have also been studied.

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.

Activation of peroxisome proliferator-activated receptor-α enhances fatty acid oxidation in human adipocytes

International Nuclear Information System (INIS)

Lee, Joo-Young; Hashizaki, Hikari; Goto, Tsuyoshi; Sakamoto, Tomoya; Takahashi, Nobuyuki; Kawada, Teruo

2011-01-01

Highlights: → PPARα activation increased mRNA expression levels of adipocyte differentiation marker genes and GPDH activity in human adipocytes. → PPARα activation also increased insulin-dependent glucose uptake in human adipocytes. → PPARα activation did not affect lipid accumulation in human adipocytes. → PPARα activation increased fatty acid oxidation through induction of fatty acid oxidation-related genes in human adipocytes. -- Abstract: Peroxisome proliferator-activated receptor-α (PPARα) is a key regulator for maintaining whole-body energy balance. However, the physiological functions of PPARα in adipocytes have been unclarified. We examined the functions of PPARα using human multipotent adipose tissue-derived stem cells as a human adipocyte model. Activation of PPARα by GW7647, a potent PPARα agonist, increased the mRNA expression levels of adipocyte differentiation marker genes such as PPARγ, adipocyte-specific fatty acid-binding protein, and lipoprotein lipase and increased both GPDH activity and insulin-dependent glucose uptake level. The findings indicate that PPARα activation stimulates adipocyte differentiation. However, lipid accumulation was not changed, which is usually observed when PPARγ is activated. On the other hand, PPARα activation by GW7647 treatment induced the mRNA expression of fatty acid oxidation-related genes such as CPT-1B and AOX in a PPARα-dependent manner. Moreover, PPARα activation increased the production of CO 2 and acid soluble metabolites, which are products of fatty acid oxidation, and increased oxygen consumption rate in human adipocytes. The data indicate that activation of PPARα stimulates both adipocyte differentiation and fatty acid oxidation in human adipocytes, suggesting that PPARα agonists could improve insulin resistance without lipid accumulation in adipocytes. The expected effects of PPARα activation are very valuable for managing diabetic conditions accompanied by obesity, because

Measurement of the rates of oxindole-3-acetic acid turnover, and indole-3-acetic acid oxidation in Zea mays seedlings

Science.gov (United States)

Nonhebel, H. M.; Bandurski, R. S. (Principal Investigator)

1986-01-01

Oxindole-3-acetic acid is the principal catabolite of indole-3-acetic acid in Zea mays seedlings. In this paper measurements of the turnover of oxindole-3-acetic acid are presented and used to calculate the rate of indole-3-acetic acid oxidation. [3H]Oxindole-3-acetic acid was applied to the endosperm of Zea mays seedlings and allowed to equilibrate for 24 h before the start of the experiment. The subsequent decrease in its specific activity was used to calculate the turnover rate. The average half-life of oxindole-3-acetic acid in the shoots was found to be 30 h while that in the kernels had an average half-life of 35h. Using previously published values of the pool sizes of oxindole-3-acetic acid in shoots and kernels from seedlings of the same age and variety, and grown under the same conditions, the rate of indole-3-acetic acid oxidation was calculated to be 1.1 pmol plant-1 h-1 in the shoots and 7.1 pmol plant-1 h-1 in the kernels.

Loss of Hepatic Mitochondrial Long-Chain Fatty Acid Oxidation Confers Resistance to Diet-Induced Obesity and Glucose Intolerance

Directory of Open Access Journals (Sweden)

Jieun Lee

2017-07-01

Full Text Available The liver has a large capacity for mitochondrial fatty acid β-oxidation, which is critical for systemic metabolic adaptations such as gluconeogenesis and ketogenesis. To understand the role of hepatic fatty acid oxidation in response to a chronic high-fat diet (HFD, we generated mice with a liver-specific deficiency of mitochondrial long-chain fatty acid β-oxidation (Cpt2L−/− mice. Paradoxically, Cpt2L−/− mice were resistant to HFD-induced obesity and glucose intolerance with an absence of liver damage, although they exhibited serum dyslipidemia, hepatic oxidative stress, and systemic carnitine deficiency. Feeding an HFD induced hepatokines in mice, with a loss of hepatic fatty acid oxidation that enhanced systemic energy expenditure and suppressed adiposity. Additionally, the suppression in hepatic gluconeogenesis was sufficient to improve HFD-induced glucose intolerance. These data show that inhibiting hepatic fatty acid oxidation results in a systemic hormetic response that protects mice from HFD-induced obesity and glucose intolerance.

Application of titanium oxide nanotube films containing gold nanoparticles for the electroanalytical determination of ascorbic acid

Energy Technology Data Exchange (ETDEWEB)

Hosseini, Mir Ghasem, E-mail: mg-hosseini@tabrizu.ac.ir; Faraji, Masoud; Momeni, Mohamad Mohsen

2011-03-31

Au/TiO{sub 2}/Ti electrodes have been prepared by galvanic deposition of gold particles on TiO{sub 2} nanotube substrates. Titanium oxide nanotubes are fabricated by anodizing titanium foil in a Dimethyl Sulfoxide electrolyte containing fluoride. The scanning electron microscopy results indicated that gold particles are homogeneously deposited on the surface of TiO{sub 2} nanotubes. The TiO{sub 2} layers consist of individual tubes of about 40-80 nm diameters. The electro-catalytic behavior of Au/TiO{sub 2}/Ti and flat gold electrodes for the ascorbic acid electro-oxidation was studied by cyclic voltammetry. The results showed that the flat gold electrode is not suitable for the oxidation of ascorbic acid. However, the Au/TiO{sub 2}/Ti electrodes are shown to possess catalytic activity toward the oxidation reaction. Catalytic oxidation peak current showed a linear dependence on the ascorbic acid concentration and a linear calibration curve is obtained in the concentration range of 1-5 mM of ascorbic acid. Also, determination of ascorbic acid in real samples was evaluated. The obtained results were found to be satisfactory. Finally the effects of interference on the detection of ascorbic acid were investigated.

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...

Polyoxometalate electrocatalysts based on earth-abundant metals for efficient water oxidation in acidic media

Science.gov (United States)

Blasco-Ahicart, Marta; Soriano-López, Joaquín; Carbó, Jorge J.; Poblet, Josep M.; Galan-Mascaros, J. R.

2018-01-01

Water splitting is a promising approach to the efficient and cost-effective production of renewable fuels, but water oxidation remains a bottleneck in its technological development because it largely relies on noble-metal catalysts. Although inexpensive transition-metal oxides are competitive water oxidation catalysts in alkaline media, they cannot compete with noble metals in acidic media, in which hydrogen production is easier and faster. Here, we report a water oxidation catalyst based on earth-abundant metals that performs well in acidic conditions. Specifically, we report the enhanced catalytic activity of insoluble salts of polyoxometalates with caesium or barium counter-cations for oxygen evolution. In particular, the barium salt of a cobalt-phosphotungstate polyanion outperforms the state-of-the-art IrO2 catalyst even at pH < 1, with an overpotential of 189 mV at 1 mA cm-2. In addition, we find that a carbon-paste conducting support with a hydrocarbon binder can improve the stability of metal-oxide catalysts in acidic media by providing a hydrophobic environment.

Fatty acid profile, color and lipid oxidation of organic fermented sausage during chilling storage as influenced by acid whey and probiotic strains addition

Directory of Open Access Journals (Sweden)

Karolina Maria Wójciak

2015-02-01

Full Text Available Organic fermented sausages typically spoil during long-term storage due to oxidative rancidity. The application of natural antioxidants to meat stuffing is a major practice intended to inhibit the oxidation process and color changes. This study aimed to assess the effect of two unusual starter cultures: three probiotic strains (Lactobacillus casei LOCK 0900, Lactobacillus casei LOCK 0908 and Lactobacillus paracasei LOCK 0919 and lactic acid bacteria from acid whey on model fermented sausage type products focusing on oxidative stability by measuring instrumental color (L*, a*, b* values, conjugated dienes (CD, TBARS immediately after 21 days of ripening (0 and after 90 and 180 days of refrigerated storage (4 ºC. Determination of fatty acid composition, in meat product was performed after ripening and after 180 days of storage. At the end of the storage period, the salted sausages were characterized by the same content of polyunsaturated fatty acids (PUFA compared to cured samples. The addition of acid whey and a mixture of probiotic strains to nitrite-free sausage formulation was barely able to protect lipids against oxidation in comparison to nitrite during vacuum storage. Surprisingly, the use of acid whey has an influence on the desired red-pinkish color of organic fermented sausage after ripening and after 180 days of storage period.

Oxidation of hydrogen peroxide by [Ni (cyclam)] in aqueous acidic ...

Indian Academy of Sciences (India)

Oxidation of hydrogen peroxide by tris(2,2 -bipyridine) and tris(4,4 -dimethyl-2,2 - bipyridine) complexes of osmium(III), iron(III), ruthenium(III), and nickel(III) studied in acidic and neutral aqueous media, show an inverse acid depen- dence over the pH the range 6.0–8.5.12 Kinetic mea- surements with an excess of H2O2 ...

Quantification of Fatty Acid Oxidation Products Using On-line High Performance Liquid Chromatography Tandem Mass Spectrometry

Science.gov (United States)

Levison, Bruce S.; Zhang, Renliang; Wang, Zeneng; Fu, Xiaoming; DiDonato, Joseph A.; Hazen, Stanley L.

2013-01-01

Oxidized fatty acids formed via lipid peroxidation are implicated in pathological processes such as inflammation and atherosclerosis. A number of methods may be used to detect specific oxidized fatty acids containing a single or multiple combinations of epoxide, hydroxyl, ketone and hydroperoxide moieties on varying carbon chain lengths from C8 up to C30. Some of these methods are nonspecific and their use in biological systems is fraught with difficulty. Measures of specific-oxidized fatty acid derivatives help in identifying oxidation pathways in pathological processes. We used liquid chromatography coupled with electrospray ionization tandem mass spectrometry (LC-MS/MS) as efficient, selective and sensitive methods for identifying and analyzing multiple specific fatty acid peroxidation products in human plasma and other biological matrices. We then distilled the essential components of a number of these analyses to provide an efficient protocol by which fatty acid oxidation products and their parent compounds can be determined. In this protocol, addition of synthetic internal standard to the sample, followed by base hydrolysis at elevated temperature, and liquid-liquid phase sample extraction with lighter than water solvents facilitates isolation of the oxidized fatty acid species. These species can be identified and accurately quantified using stable isotope dilution and multiple reaction monitoring. Use of a coupled multiplexed gradient HPLC system on the front end enables high-throughput chromatography and more efficient use of mass spectrometer time. PMID:23499838

The oxidized form of vitamin C, dehydroascorbic acid, regulates neuronal energy metabolism.

Science.gov (United States)

Cisternas, Pedro; Silva-Alvarez, Carmen; Martínez, Fernando; Fernandez, Emilio; Ferrada, Luciano; Oyarce, Karina; Salazar, Katterine; Bolaños, Juan P; Nualart, Francisco

2014-05-01

Vitamin C is an essential factor for neuronal function and survival, existing in two redox states, ascorbic acid (AA), and its oxidized form, dehydroascorbic acid (DHA). Here, we show uptake of both AA and DHA by primary cultures of rat brain cortical neurons. Moreover, we show that most intracellular AA was rapidly oxidized to DHA. Intracellular DHA induced a rapid and dramatic decrease in reduced glutathione that was immediately followed by a spontaneous recovery. This transient decrease in glutathione oxidation was preceded by an increase in the rate of glucose oxidation through the pentose phosphate pathway (PPP), and a concomitant decrease in glucose oxidation through glycolysis. DHA stimulated the activity of glucose-6-phosphate dehydrogenase, the rate-limiting enzyme of the PPP. Furthermore, we found that DHA stimulated the rate of lactate uptake by neurons in a time- and dose-dependent manner. Thus, DHA is a novel modulator of neuronal energy metabolism by facilitating the utilization of glucose through the PPP for antioxidant purposes. © 2014 International Society for Neurochemistry.

Characterization of the oleic acid/iron oxide nanoparticle interface by magnetic resonance

Energy Technology Data Exchange (ETDEWEB)

Masur, S., E-mail: sabrina.masur@uni-due.de; Zingsem, B.; Marzi, T.; Meckenstock, R.; Farle, M.

2016-10-01

The synthesis of colloidal nanoparticles involves surfactant molecules, which bind to the particle surface and stabilize nanoparticles against aggregation. In many cases these protecting shells also can be used for further functionalization. In this study, we investigated monodisperse single crystalline iron oxide core/shell nanoparticles (Fe{sub x}O{sub y}-NPs) in situ covered with an oleic acid layer which showed two electron spin resonance (ESR) signals. The nanoparticles with the ligands attached were characterized by transmission electron microscopy (TEM) and ferro- and paramagnetic resonance (FMR, EPR). Infrared spectroscopy confirmed the presence of the functional groups and revealed that the oleic acid (OA) is chemisorbed as a carboxylate on the iron oxide and is coordinated symmetrically to the oxide atoms. We show that the EPR signal of the OA ligand molecule can be used as a local probe to determine the temperature changes at the surface of the nanoparticle. - Highlights: • Monodisperse single crystalline iron oxide core/shell nanoparticles (Fe{sub x}O{sub y}-NPs) in situ covered with an oleic acid layer two electron spin resonance (ESR) signals. • We show that the EPR signal of the OA ligand molecule can be used as a local probe to determine the temperature changes at the surface of the nanoparticle.

Investigation of Influential Parameters in Deep Oxidative Desulfurization of Dibenzothiophene with Hydrogen Peroxide and Formic Acid

Directory of Open Access Journals (Sweden)

Alireza Haghighat Mamaghani

2013-01-01

Full Text Available An effective oxidative system consisting of hydrogen peroxide, formic acid, and sulfuric acid followed by an extractive stage were implemented to remove dibenzothiophene in the simulated fuel oil. The results revealed such a great performance in the case of H2O2 in the presence of formic and sulfuric acids that led to the removal of sulfur compounds. Sulfuric acid was employed to increase the acidity of media as well as catalytic activity together with formic acid. The oxidation reaction was followed by a liquid-liquid extraction stage using acetonitrile as a polar solvent to remove produced sulfones from the model fuel. The impact of operating parameters including the molar ratio of formic acid to sulfur (, hydrogen peroxide to sulfur (, and the time of reaction was investigated using Box-Behnken experimental design for oxidation of the model fuel. A significant quadratic model was introduced for the sulfur removal as a function of effective parameters by the statistic analysis.

Development of preparative and analytical methods of the hop bitter acid oxide fraction and chemical properties of its components.

Science.gov (United States)

Taniguchi, Yoshimasa; Matsukura, Yasuko; Taniguchi, Harumi; Koizumi, Hideki; Katayama, Mikio

2015-01-01

The bitter acids in hops (Humulus lupulus L.) and beer, such as α-, β-, and iso-α-acids, are known to affect beer quality and display various physiological effects. However, these compounds readily oxidize, and the effect of the oxides on the properties of beer or their potential health benefits are not well understood. In this study, we developed a simple preparative method for the bitter acid oxide fraction derived from hops and designated the constituents as matured hop bitter acids (MHBA). HPLC-PDA-ESI/HRMS and MS(2) revealed that MHBA are primarily composed of α-acid-derived oxides, which possess a common β-tricarbonyl moiety in their structures similar to α-, β-, and iso-α-acids. We also developed a quantitative analytical method of whole MHBA by HPLC, which showed high precision and reproducibility. Using our newly developed method, the concentration of whole MHBA in several commercial beers was evaluated. Our results will promote the study of bitter acid oxides.

The Depolymerization of Poly(Ethylene Terephthalate) (PET) Using N-Heterocyclic Carbenes from Ionic Liquids

Science.gov (United States)

Kamber, Nahrain E.; Tsujii, Yasuhito; Keets, Kate; Waymouth, Robert M.; Pratt, Russell C.; Nyce, Gregory W.; Hedrick, James L.

2010-01-01

The depolymerization of the plastic polyethylene terephthalate (PET or PETE) is described in this laboratory procedure. The transesterification reaction used to depolymerize PET employs a highly efficient N-heterocyclic carbene catalyst derived from a commercially available imidazolium ionic liquid. N-heterocyclic carbenes are potent nucleophilic…

Kinetics and mechanism of the oxidation of some neutral and acidic ...

Indian Academy of Sciences (India)

Unknown

The effect of solvent composition indicate that the rate of reaction increases with increase in the po- larity of the medium. Addition of ... oxidation of several neutral and acidic α-amino ac- ids by TBATB in aqueous acetic acid solution, and the mechanistic aspects are discussed in this paper. 2. Experimental. 2.1 Materials.

Syntrophic acetate oxidation in two-phase (acid-methane) anaerobic digesters.

Science.gov (United States)

Shimada, T; Morgenroth, E; Tandukar, M; Pavlostathis, S G; Smith, A; Raskin, L; Kilian, R E

2011-01-01

The microbial processes involved in two-phase anaerobic digestion were investigated by operating a laboratory-scale acid-phase (AP) reactor and analyzing two full-scale, two-phase anaerobic digesters operated under mesophilic (35 °C) conditions. The digesters received a blend of primary sludge and waste activated sludge (WAS). Methane levels of 20% in the laboratory-scale reactor indicated the presence of methanogenic activity in the AP. A phylogenetic analysis of an archaeal 16S rRNA gene clone library of one of the full-scale AP digesters showed that 82% and 5% of the clones were affiliated with the orders Methanobacteriales and Methanosarcinales, respectively. These results indicate that substantial levels of aceticlastic methanogens (order Methanosarcinales) were not maintained at the low solids retention times and acidic conditions (pH 5.2-5.5) of the AP, and that methanogenesis was carried out by hydrogen-utilizing methanogens of the order Methanobacteriales. Approximately 43, 31, and 9% of the archaeal clones from the methanogenic phase (MP) digester were affiliated with the orders Methanosarcinales, Methanomicrobiales, and Methanobacteriales, respectively. A phylogenetic analysis of a bacterial 16S rRNA gene clone library suggested the presence of acetate-oxidizing bacteria (close relatives of Thermacetogenium phaeum, 'Syntrophaceticus schinkii,' and Clostridium ultunense). The high abundance of hydrogen consuming methanogens and the presence of known acetate-oxidizing bacteria suggest that acetate utilization by acetate oxidizing bacteria in syntrophic interaction with hydrogen-utilizing methanogens was an important pathway in the second-stage of the two-phase digestion, which was operated at high ammonium-N concentrations (1.0 and 1.4 g/L). A modified version of the IWA Anaerobic Digestion Model No. 1 (ADM1) with extensions for syntrophic acetate oxidation and weak-acid inhibition adequately described the dynamic profiles of volatile acid production

Thermal degradation and isothermal crystalline behavior of poly(trimethylene terephthalate)

Institute of Scientific and Technical Information of China (English)

Jian Liu; Shu Guang Bian; Min Xiao; Shuan Jin Wang; Yue Zhong Meng

2009-01-01

Poly(trimethylene terephthalate)(PTT)is an excellent fiber material.Its thermal degradation and isothermal crystalline behaviors were in this study investigated using thermogravimetric analysis(TGA),thermogravimetric analysis-Fourier transform infrared spectroscopy(TGA-FTIR)analysis,differential scanning calorimetry(DSC)and X-ray diffraction(XRD).The thermal degradation mechanism of PTT follows Mclafferty rearrangement principle.The PTT with intrinsicviscosity(IV)of 0.74 dL/g has a maximum crystallinity of about 55%at 190℃,as demonstrated by DSC and XRD measurements consistently.

Electrochemical oxidation of 243Am(III) in nitric acid by a terpyridyl-derivatized electrode

Energy Technology Data Exchange (ETDEWEB)

Dares, C. J.; Lapides, A. M.; Mincher, B. J.; Meyer, T. J.

2015-11-05

A high surface area, tin-doped indium oxide electrode surface-derivatized with a terpyridine ligand has been applied to the oxidation of trivalent americium to Am(V) and Am(VI) in nitric acid. Potentials as low as 1.8 V vs. the saturated calomel electrode are used, 0.7 V lower than the 2.6 V potential for one-electron oxidation of Am(III) to Am(IV) in 1 M acid. This simple electrochemical procedure provides, for the first time, a method for accessing the higher oxidation states of Am in non-complexing media for developing the coordination chemistries of Am(V) and Am(VI) and, more importantly, for separation of americium from nuclear waste streams.

ANTIOXIDANT AND PRO-OXIDANT EFFECT OF ASCORBIC ACID

Directory of Open Access Journals (Sweden)

Goran Rankovic

2005-01-01

Full Text Available Free radicals attack proteins, lipids, enzymes and DNA causing pathological changes in organism. There are many mechanisms that organism uses to fight against free radicals. Ascorbic acid is one of the strongest reducers and eliminators of free radicals. It reduces stable oxygenic, azoth and thyol radicals and acts as a primary defense against water radicals in blood. When radicals are dissolved in water suspensions of erythrocytes and low density lipoproteins (LDL, ascorbic acid catches and eliminates free radicals before they arrive to the membrane and LDL molecules. Even though ascorbic acid is not capable of eliminating free radicals out of fluid medium, it acts as synergist to alpha-tocopherol in lipid section, contributes to the lessening of lipid tocoperoxil radicals, and above all, regenerates alpha-tocopherol. Ascorbic acid may act as pro-oxidant under in vitro conditions in the presence of metals; however, this effect is probably not important under in vivo conditions where metal ions, being sequestered, become second reducers.

Pulse radiolysis study on oxidation reactions of gallic acid

International Nuclear Information System (INIS)

Dwibedy, P.; Dey, G.R.; Naik, D.B.; Kishore, Kamal

1998-01-01

Reactions of OH . /O - and other oxidising radicals viz. N 3 . , Br 2 .- , Cl 2 .- with gallic acid (GA) have been studied at various pHs. At pH 6.8, OH . radicals react with GA giving an adduct which in turn reacts with the parent GA to give a dimeric species. At pH 9.7, the initial OH adduct formed is able to oxidize GA to give a semi-oxidised species. At pH 12 and ∼ 13.6, OH . /O .- radicals directly bring about oxidation of GA. (author)

Molecular characterization of urban organic aerosol in tropical India: contributions of primary emissions and secondary photooxidation

Directory of Open Access Journals (Sweden)

P. Q. Fu

2010-03-01

Full Text Available Organic molecular composition of PM₁₀ samples, collected at Chennai in tropical India, was studied using capillary gas chromatography/mass spectrometry. Fourteen organic compound classes were detected in the aerosols, including aliphatic lipids, sugar compounds, lignin products, terpenoid biomarkers, sterols, aromatic acids, hydroxy-/polyacids, phthalate esters, hopanes, Polycyclic Aromatic Hydrocarbons (PAHs, and photooxidation products from biogenic Volatile Organic Compounds (VOCs. At daytime, phthalate esters were found to be the most abundant compound class; however, at nighttime, fatty acids were the dominant one. Di-(2-ethylhexyl phthalate, C₁₆ fatty acid, and levoglucosan were identified as the most abundant single compounds. The nighttime maxima of most organics in the aerosols indicate a land/sea breeze effect in tropical India, although some other factors such as local emissions and long-range transport may also influence the composition of organic aerosols. However, biogenic VOC oxidation products (e.g., 2-methyltetrols, pinic acid, 3-hydroxyglutaric acid and β-caryophyllinic acid showed diurnal patterns with daytime maxima. Interestingly, terephthalic acid was maximized at nighttime, which is different from those of phthalic and isophthalic acids. A positive relation was found between 1,3,5-triphenylbenzene (a tracer for plastic burning and terephthalic acid, suggesting that the field burning of municipal solid wastes including plastics is a significant source of terephthalic acid. Organic compounds were further categorized into several groups to clarify their sources. Fossil fuel combustion (24–43% was recognized as the most significant source for the total identified compounds, followed by plastic emission (16–33%, secondary oxidation (8.6–23%, and microbial/marine sources (7.2–17%. In contrast, the contributions of terrestrial plant waxes (5.9–11% and biomass burning (4.2–6.4% were relatively

Biogenic precipitation of manganese oxides and enrichment of heavy metals at acidic soil pH

Science.gov (United States)

Mayanna, Sathish; Peacock, Caroline L.; Schäffner, Franziska; Grawunder, Anja; Merten, Dirk; Kothe, Erika; Büchel, Georg

2014-05-01

The precipitation of biogenic Mn oxides at acidic pH is rarely reported and poorly understood, compared to biogenic Mn oxide precipitation at near neutral conditions. Here we identified and investigated the precipitation of biogenic Mn oxides in acidic soil, and studied their role in the retention of heavy metals, at the former uranium mining site of Ronneburg, Germany. The site is characterized by acidic pH, low carbon content and high heavy metal loads including rare earth elements. Specifically, the Mn oxides were present in layers identified by detailed soil profiling and within these layers pH varied from 4.7 to 5.1, Eh varied from 640 to 660 mV and there were enriched total metal contents for Ba, Ni, Co, Cd and Zn in addition to high Mn levels. Using electron microprobe analysis, synchrotron X-ray diffraction and X-ray absorption spectroscopy, we identified poorly crystalline birnessite (δ-MnO2) as the dominant Mn oxide in the Mn layers, present as coatings covering and cementing quartz grains. With geochemical modelling we found that the environmental conditions at the site were not favourable for chemical oxidation of Mn(II), and thus we performed 16S rDNA sequencing to isolate the bacterial strains present in the Mn layers. Bacterial phyla present in the Mn layers belonged to Firmicutes, Actinobacteria and Proteobacteria, and from these phyla we isolated six strains of Mn(II) oxidizing bacteria and confirmed their ability to oxidise Mn(II) in the laboratory. The biogenic Mn oxide layers act as a sink for metals and the bioavailability of these metals was much lower in the Mn layers than in adjacent layers, reflecting their preferential sorption to the biogenic Mn oxide. In this presentation we will report our findings, concluding that the formation of natural biogenic poorly crystalline birnessite can occur at acidic pH, resulting in the formation of a biogeochemical barrier which, in turn, can control the mobility and bioavailability of heavy metals in

Cyclic voltammetric study of electro-oxidation of methanol on platinum electrode in acidic and neutral media

International Nuclear Information System (INIS)

Khan, A.S.A.; Ahmed, R.; Mirza, M.L.

2007-01-01

The electro-oxidation of methanol on electrochemically treated platinum foil was investigated in acidic and neutral media for comparison of cyclic voltammetric characteristics and elucidation of mechanism of electro-oxidation of methanol. The surface area and roughness factor of platinum electrode was calculated. The electro-oxidation of mathanol is an irreversible process giving. anodic peaks in both anodic and cathodic sweep. The characteristic peaks of electrooxidation of methanol appeared at almost the same potential region in both acidic and neutral media. In neutral medium, certain additional cathodic/anodic peaks appeared which were confirmed to arise by the reduction/oxidation of hydrogen ions. The exchange current density and heterogeneous electron transfer rate constant was higher in neutral medium as. compared with acidic medium. The thermodynamic parameters delta H, delta S, and delta G/sub 298/ were calculated. The values of delta H and delta G/sub 298/were positive which indicated that the process of electro-oxidation of methanol is an endothermic and nonspontaneous. The mechanism of electro-oxidation of methanol was same in both acidic and neutral media involving the formation of various adsorbed intermediate species through dissociative adsorption steps leading to the formation of Co adsorbed radicals, which are removed. during interaction with adsorbed hydrous oxides provided by the oxidation of adsorbed water molecules. The higher rate of electro-oxidation of methanol in neutral medium was interpreted in the tight of electrochemical mechanism and was attributed to the presence of comparatively small amount of hydrogen ions only along the surface of working electrode, which are produced during electro-oxidation of methanol. (author)

Loss of Hepatic Mitochondrial Long-Chain Fatty Acid Oxidation Confers Resistance to Diet-Induced Obesity and Glucose Intolerance.

Science.gov (United States)

Lee, Jieun; Choi, Joseph; Selen Alpergin, Ebru S; Zhao, Liang; Hartung, Thomas; Scafidi, Susanna; Riddle, Ryan C; Wolfgang, Michael J

2017-07-18

The liver has a large capacity for mitochondrial fatty acid β-oxidation, which is critical for systemic metabolic adaptations such as gluconeogenesis and ketogenesis. To understand the role of hepatic fatty acid oxidation in response to a chronic high-fat diet (HFD), we generated mice with a liver-specific deficiency of mitochondrial long-chain fatty acid β-oxidation (Cpt2 L-/- mice). Paradoxically, Cpt2 L-/- mice were resistant to HFD-induced obesity and glucose intolerance with an absence of liver damage, although they exhibited serum dyslipidemia, hepatic oxidative stress, and systemic carnitine deficiency. Feeding an HFD induced hepatokines in mice, with a loss of hepatic fatty acid oxidation that enhanced systemic energy expenditure and suppressed adiposity. Additionally, the suppression in hepatic gluconeogenesis was sufficient to improve HFD-induced glucose intolerance. These data show that inhibiting hepatic fatty acid oxidation results in a systemic hormetic response that protects mice from HFD-induced obesity and glucose intolerance. Copyright © 2017 The Author(s). Published by Elsevier Inc. All rights reserved.

Oxidative modification of lipoic acid by HNE in Alzheimer disease brain

Directory of Open Access Journals (Sweden)

Sarita S. Hardas

2013-01-01

Full Text Available Alzheimer disease (AD is an age-related neurodegenerative disease characterized by the presence of three pathological hallmarks: synapse loss, extracellular senile plaques (SP and intracellular neurofibrillary tangles (NFTs. The major component of SP is amyloid β-peptide (Aβ, which has been shown to induce oxidative stress. The AD brain shows increased levels of lipid peroxidation products, including 4-hydroxy-2-nonenal (HNE. HNE can react covalently with Cys, His, or Lys residues on proteins, altering structure and function of the latter. In the present study we measured the levels of the HNE-modified lipoic acid in brain of subjects with AD and age-matched controls. Lipoic acid is a key co-factor for a number of proteins including pyruvate dehydrogenase and α-ketoglutarate dehydrogenase, key complexes for cellular energetics. We observed a significant decrease in the levels of HNE-lipoic acid in the AD brain compared to that of age-matched controls. To investigate this phenomenon further, the levels and activity of lipoamide dehydrogenase (LADH were measured in AD and control brains. Additionally, LADH activities were measured after in-vitro HNE-treatment to mice brains. Both LADH levels and activities were found to be significantly reduced in AD brain compared to age-matched control. HNE-treatment also reduced the LADH activity in mice brain. These data are consistent with a two-hit hypothesis of AD: oxidative stress leads to lipid peroxidation that, in turn, causes oxidative dysfunction of key energy-related complexes in mitochondria, triggering neurodegeneration. This study is consonant with the notion that lipoic acid supplementation could be a potential treatment for the observed loss of cellular energetics in AD and potentiate the antioxidant defense system to prevent or delay the oxidative stress in and progression of this devastating dementing disorder.

Measurement of the oxidation-extraction of uranium from wet-process phosphoric acid

International Nuclear Information System (INIS)

Lawes, B.C.

1985-01-01

The present invention relates to processes for the recovery of uranium from wet-process phosphoric acid and more particularly to the oxidation-extraction steps in the DEPA-TOPO process for such recovery. A more efficient use of oxidant is obtained by monitoring the redox potential during the extraction step

Natural resistance to ascorbic acid induced oxidative stress is mainly mediated by catalase activity in human cancer cells and catalase-silencing sensitizes to oxidative stress

Directory of Open Access Journals (Sweden)

Klingelhoeffer Christoph

2012-05-01

Full Text Available Abstract Background Ascorbic acid demonstrates a cytotoxic effect by generating hydrogen peroxide, a reactive oxygen species (ROS involved in oxidative cell stress. A panel of eleven human cancer cell lines, glioblastoma and carcinoma, were exposed to serial dilutions of ascorbic acid (5-100 mmol/L. The purpose of this study was to analyse the impact of catalase, an important hydrogen peroxide-detoxifying enzyme, on the resistance of cancer cells to ascorbic acid mediated oxidative stress. Methods Effective concentration (EC50 values, which indicate the concentration of ascorbic acid that reduced the number of viable cells by 50%, were detected with the crystal violet assay. The level of intracellular catalase protein and enzyme activity was determined. Expression of catalase was silenced by catalase-specific short hairpin RNA (sh-RNA in BT-20 breast carcinoma cells. Oxidative cell stress induced apoptosis was measured by a caspase luminescent assay. Results The tested human cancer cell lines demonstrated obvious differences in their resistance to ascorbic acid mediated oxidative cell stress. Forty-five percent of the cell lines had an EC50 > 20 mmol/L and fifty-five percent had an EC50 50 of 2.6–5.5 mmol/L, glioblastoma cells were the most susceptible cancer cell lines analysed in this study. A correlation between catalase activity and the susceptibility to ascorbic acid was observed. To study the possible protective role of catalase on the resistance of cancer cells to oxidative cell stress, the expression of catalase in the breast carcinoma cell line BT-20, which cells were highly resistant to the exposure to ascorbic acid (EC50: 94,9 mmol/L, was silenced with specific sh-RNA. The effect was that catalase-silenced BT-20 cells (BT-20 KD-CAT became more susceptible to high concentrations of ascorbic acid (50 and 100 mmol/L. Conclusions Fifty-five percent of the human cancer cell lines tested were unable to protect themselves

Kinetics and mechanism of oxidation of acetanilide by quinquevalent vanadium in acid medium

International Nuclear Information System (INIS)

Gupta, R.

1990-01-01

The kinetics of the oxidation of acetanilide with vanadium(V) in sulphuric acid medium at constant ionic strength has been studied. The reaction is first order with oxidant. The order of reaction in acetanilide varies from one to zero. The reaction follows an acid catalyzed independent path, exhibiting square dependence in H + . A Bunnett plot indicates that the water acts as a nucleophile. The thermodynamic parameters have been computed. A probable reaction mechanism and rate law consistent with these data are given. (Author)

Bacterial Oxidation and Reduction of Iron in the Processes of Creation and Treatment of Acid Mining Waters

Directory of Open Access Journals (Sweden)

Daniel Kupka

2004-12-01

Full Text Available Acid mine drainages (AMDs arise at the weathering of sulphidic minerals. The occurrence of acidic streams is commonly associated with the human mining activities. Due to the disruption and excavation of sulphide deposits, the oxidation processes have initiated. Acidic products of sulphide oxidation accelerate the degradation of accompanying minerals. AMDs typically contain high concentrations of sulfuric acid and soluble metals and cause serious ecological problems due to the water pollution and the devastation of adjacent country. Microbial life in these extremely acidic environments may be considerably diverse. AMDs are abundant in bacteria capable to oxidize and/or to reduce iron. The rate of bacterial oxidation of ferrous iron released from pyrite surfaces is up to one million times faster than the chemical oxidation rate at low pH. Bacterial regeneration of ferric iron maintains the continuity of pyrite oxidation and the production of AMDs. Another group of microorganisms living in these environments are acidophilic ferric iron reducing bacteria. This group of microorganisms has been discovered only relatively recently. Acidophilic heterotrophic bacteria reduce ferric iron in either soluble or solid forms to ferrous iron. The reductive dissolution of ferric iron minerals brings about a mobilization of iron as well as associated heavy metals. The Bacterial oxidation and reduction of iron play an important role in the transformation of either crystalline or amorphous iron-containing minerals, including sulphides, oxides, hydroxysulfates, carbonates and silicates. This work discusses the role of acidophilic bacteria in the natural iron cycling and the genesis of acidic effluents. The possibilities of application of iron bacteria in the remediation of AMDs are also considered.

Activation of peroxisome proliferator-activated receptor-{alpha} enhances fatty acid oxidation in human adipocytes

Energy Technology Data Exchange (ETDEWEB)

Lee, Joo-Young; Hashizaki, Hikari; Goto, Tsuyoshi; Sakamoto, Tomoya; Takahashi, Nobuyuki [Laboratory of Molecular Function of Food, Division of Food Science and Biotechnology, Graduate School of Agriculture, Kyoto University, Uji, Kyoto 611-0011 (Japan); Kawada, Teruo, E-mail: fat@kais.kyoto-u.ac.jp [Laboratory of Molecular Function of Food, Division of Food Science and Biotechnology, Graduate School of Agriculture, Kyoto University, Uji, Kyoto 611-0011 (Japan)

2011-04-22

Highlights: {yields} PPAR{alpha} activation increased mRNA expression levels of adipocyte differentiation marker genes and GPDH activity in human adipocytes. {yields} PPAR{alpha} activation also increased insulin-dependent glucose uptake in human adipocytes. {yields} PPAR{alpha} activation did not affect lipid accumulation in human adipocytes. {yields} PPAR{alpha} activation increased fatty acid oxidation through induction of fatty acid oxidation-related genes in human adipocytes. -- Abstract: Peroxisome proliferator-activated receptor-{alpha} (PPAR{alpha}) is a key regulator for maintaining whole-body energy balance. However, the physiological functions of PPAR{alpha} in adipocytes have been unclarified. We examined the functions of PPAR{alpha} using human multipotent adipose tissue-derived stem cells as a human adipocyte model. Activation of PPAR{alpha} by GW7647, a potent PPAR{alpha} agonist, increased the mRNA expression levels of adipocyte differentiation marker genes such as PPAR{gamma}, adipocyte-specific fatty acid-binding protein, and lipoprotein lipase and increased both GPDH activity and insulin-dependent glucose uptake level. The findings indicate that PPAR{alpha} activation stimulates adipocyte differentiation. However, lipid accumulation was not changed, which is usually observed when PPAR{gamma} is activated. On the other hand, PPAR{alpha} activation by GW7647 treatment induced the mRNA expression of fatty acid oxidation-related genes such as CPT-1B and AOX in a PPAR{alpha}-dependent manner. Moreover, PPAR{alpha} activation increased the production of CO{sub 2} and acid soluble metabolites, which are products of fatty acid oxidation, and increased oxygen consumption rate in human adipocytes. The data indicate that activation of PPAR{alpha} stimulates both adipocyte differentiation and fatty acid oxidation in human adipocytes, suggesting that PPAR{alpha} agonists could improve insulin resistance without lipid accumulation in adipocytes. The expected

Genotoxicity and oxidative stress of microwave radiation role of ascorbic acid

International Nuclear Information System (INIS)

Desouky, O.S.; Abdel Karim, M.A.; Deiaa El Deen, D.A.; Nayal, N.A.

2005-01-01

Radiofrequency fields and especially microwaves are very important part of electromagnetic spectrum that can produce generations of reactive oxygen species, and thus can affect DNA and cause chromosomal aberrations. So this effect can be diminished by the supplement of an antioxidant such as ascorbic acid. In this study, the proposed protective role of ascorbic acid was tested against the EMF induced chromosomal aberrations and lipid peroxidation. The present study proved that EMF had a clastogenic effect on the bone marrow cells of mice, either with the exposure to EMF; 950 MHz or frequency EMF; 2450 MHz. This effect was evidenced by structural and numerical chromosomal aberrations. The study also proved that EMF had an effect on oxidative stress, evidenced by increase in the level of lipid peroxide, in a dose dependent manner. So, the mechanism of EMF induced chromosomal aberrations can be explained by this oxidative stress induced by EMF exposure. The present study showed that ascorbic acid had a protective effect against both EMF induced chromosomal aberrations and oxidative stress, when it is applied concomitantly with EMF exposure either at frequency of 950 MHz or 2450 MHz. this is evident by decreases in the level of lipid peroxide and decrease in chromosomal aberrations

Effects of argon and oxygen flow rate on water vapor barrier properties of silicon oxide coatings deposited on polyethylene terephthalate by plasma enhanced chemical vapor deposition

International Nuclear Information System (INIS)

Kim, Sung-Ryong; Choudhury, Moinul Haque; Kim, Won-Ho; Kim, Gon-Ho

2010-01-01

Plasma polymer coatings were deposited from hexamethyldisiloxane on polyethylene terephthalate (PET) substrates while varying the operating conditions, such as the Ar and O 2 flow rates, at a fixed radio frequency power of 300 W. The water vapor transmission rate (WVTR) of the untreated PET was 54.56 g/m 2 /day and was decreased after depositing the silicon oxide (SiO x ) coatings. The minimum WVTR, 0.47 g/m 2 /day, was observed at Ar and O 2 flow rates of 4 and 20 sccm, respectively, with a coating thickness of 415.44 nm. The intensity of the peaks for the Si-O-Si bending at 800-820 cm -1 and Si-O-Si stretching at 1000-1150 cm -1 varied depending on the Ar and O 2 flow rates. The contact angle of the SiO x coated PET increased as the Ar flow rate was increased from 2 to 8 sccm at a fixed O 2 flow rate of 20 sccm. It decreased gradually as the oxygen flow rate increased from 12 to 28 sccm at a fixed Ar carrier gas flow rate. The examination by atomic force microscopy revealed a correlation of the SiO x morphology and the water vapor barrier performance with the Ar and O 2 flow rates. The roughness of the deposited coatings increased when either the O 2 or Ar flow rate was increased.

Oxidative Stress in The Hippocampus During Experimental Seizures Can Be Ameliorated With The Antioxidant Ascorbic Acid

Directory of Open Access Journals (Sweden)

Ítala Mônica Sales Santos

2009-01-01

Full Text Available Ascorbic acid has many nonenzymatic actions and is a powerful water-soluble antioxidant. It protects low density lipoproteins from oxidation and reduces harmful oxidants in the central nervous system. Pilocarpine-induced seizures have been suggested to be mediated by increases in oxidative stress. Current studies have suggested that antioxidant compounds may afford some level of neuroprotection against the neurotoxicity of seizures. The objective of the present study was to evaluate the neuroprotective effects of ascorbic acid (AA in rats, against the observed oxidative stress during seizures induced by pilocarpine. Wistar rats were treated with 0.9% saline (i.p., control group, ascorbic acid (500 mg/kg, i.p., AA group, pilocarpine (400 mg/kg, i.p., pilocarpine group, and the association of ascorbic acid (500 mg/kg, i.p. plus pilocarpine (400 mg/kg, i.p., 30 min before of administration of ascorbic acid (AA plus pilocarpine group. After the treatments all groups were observed for 6 h. The enzyme activities as well as the lipid peroxidation and nitrite concentrations were measured using spectrophotometric methods and the results compared to values obtained from saline and pilocarpine-treated animals. Protective effects of ascorbic acid were also evaluated on the same parameters. In pilocarpine group there was a significant increase in lipid peroxidation and nitrite level. However, no alteration was observed in superoxide dismutase and catalase activities. Antioxidant treatment significantly reduced the lipid peroxidation level and nitrite content as well as increased the superoxide dismutase and catalase activities in hippocampus of adult rats after seizures induced by pilocarpine. Our findings strongly support the hypothesis that oxidative stress in hippocampus occurs during seizures induced by pilocarpine, proving that brain damage induced by the oxidative process plays a crucial role in seizures pathogenic consequences, and also imply that a

Fumaric acid production in Saccharomyces cerevisiae by simultaneous use of oxidative and reductive routes.

Science.gov (United States)

Xu, Guoqiang; Chen, Xiulai; Liu, Liming; Jiang, Linghuo

2013-11-01

In this study, the simultaneous use of reductive and oxidative routes to produce fumaric acid was explored. The strain FMME003 (Saccharomyces cerevisiae CEN.PK2-1CΔTHI2) exhibited capability to accumulate pyruvate and was used for fumaric acid production. The fum1 mutant FMME004 could produce fumaric acid via oxidative route, but the introduction of reductive route derived from Rhizopus oryzae NRRL 1526 led to lower fumaric acid production. Analysis of the key factors associated with fumaric acid production revealed that pyruvate carboxylase had a low degree of control over the carbon flow to malic acid. The fumaric acid titer was improved dramatically when the heterologous gene RoPYC was overexpressed and 32 μg/L of biotin was added. Furthermore, under the optimal carbon/nitrogen ratio, the engineered strain FMME004-6 could produce up to 5.64 ± 0.16 g/L of fumaric acid. These results demonstrated that the proposed fermentative method is efficient for fumaric acid production. Copyright © 2013 Elsevier Ltd. All rights reserved.

Oxidative decarboxylation of glycolic and phenylacetic acids with cerium(4) catalyzed by silver ions in the sulfuric acid media

International Nuclear Information System (INIS)

Venkatesvar Rao, G.; Nagardzhun Rao, Ch.; Sajprakash, P.K.

1981-01-01

Oxidative decarboxylation of glycolic and phenylacetic acids by cerium (4) in the presence of Ag + ions is studied. The Ce(4) order equals 1, glycolic acid order in the absence of a catalyst also equals 1 and is fractional (0.5) for a catalytic reaction. The phenylacetic acid order is fractional (0.75). The Ag + ion reaction order is fractional and constitutes 0.32 for glycolic and 0.36 for phenylacetic acids. The reaction mechanism is proposed [ru

Electrocatalytic Activity of Carbonized Nanostructured Polyanilines for Oxidation Reactions: Sensing of Nitrite Ions and Ascorbic Acid

International Nuclear Information System (INIS)

Micić, Darko; Šljukić, Biljana; Zujovic, Zoran; Travas-Sejdic, Jadranka; Ćirić-Marjanović, Gordana

2014-01-01

Highlights: • Carbonized PANIs prepared from various nanostructured PANI precursors • Electroanalytical performances of carbonized PANIs evaluated using voltammetry • Study of carbonized PANIs physico-chemical properties related to electroactivity • The lowest over-potential for NO 2 − oxidation at c-PANI (+0.87 V vs. SCE) • The lowest over-potential for ascorbic acid oxidation at both c-PANI and c-PANI-SSA - Abstract: A comparative study of the electrocatalytic activity of nitrogen-containing carbon nanomaterials, prepared by the carbonization of nanostructured polyaniline (PANI) salts, for the electrooxidation reactions is presented. Nanostructured PANI salts were synthesized by the oxidative polymerization of aniline with ammonium peroxydisulfate in an aqueous solution in the presence of 5-sulfosalicylic acid (PANI-SSA), 3,5-dinitrosalicylic acid (PANI-DNSA) as well as without added acid (PANI), and subsequently carbonized to c-PANI-SSA, c-PANI-DNSA and c-PANI, respectively. Glassy carbon tip was modified with nanostructured c-PANIs and used for the investigation of sensing of nitrite and ascorbic acid in aqueous solutions as model analytes by linear sweep voltammetry. All three types of the investigated c-PANIs gave excellent response to the nitrite ions and ascorbic acid electrooxidation. The lowest peak potential for nitrite ion oxidation exhibited c-PANI (+0.87 V vs. SCE), and for ascorbic acid oxidation both c-PANI and c-PANI-SSA (ca. + 0.13 V vs. SCE). Electrochemical data were correlated with structural and textural data obtained by Raman spectroscopy, X-ray diffraction, X-ray photoelectron spectroscopy, elemental and nitrogen sorption analysis

Electronic [UV-Visible] and vibrational [FT-IR, FT-Raman] investigation and NMR-mass spectroscopic analysis of terephthalic acid using quantum Gaussian calculations.

Science.gov (United States)

Karthikeyan, N; Prince, J Joseph; Ramalingam, S; Periandy, S

2015-03-15

In this research work, the vibrational IR, polarization Raman, NMR and mass spectra of terephthalic acid (TA) were recorded. The observed fundamental peaks (IR, Raman) were assigned according to their distinctiveness region. The hybrid computational calculations were carried out for calculating geometrical and vibrational parameters by DFT (B3LYP and B3PW91) methods with 6-31++G(d,p) and 6-311++G(d,p) basis sets and the corresponding results were tabulated. The molecular mass spectral data related to base molecule and substitutional group of the compound was analyzed. The modification of the chemical property by the reaction mechanism of the injection of dicarboxylic group in the base molecule was investigated. The (13)C and (1)H NMR spectra were simulated by using the gauge independent atomic orbital (GIAO) method and the absolute chemical shifts related to TMS were compared with experimental spectra. The study on the electronic and optical properties; absorption wavelengths, excitation energy, dipole moment and frontier molecular orbital energies, were performed by hybrid Gaussian calculation methods. The orbital energies of different levels of HOMO and LUMO were calculated and the molecular orbital lobe overlapping showed the inter charge transformation between the base molecule and ligand group. From the frontier molecular orbitals (FMO), the possibility of electrophilic and nucleophilic hit also analyzed. The NLO activity of the title compound related to Polarizability and hyperpolarizability were also discussed. The present molecule was fragmented with respect to atomic mass and the mass variation depends on the substitutions have also been studied. Crown Copyright © 2014. Published by Elsevier B.V. All rights reserved.

Synthesis of acid-base bifunctional mesoporous materials by oxidation and thermolysis

Energy Technology Data Exchange (ETDEWEB)

Yu, Xiaofang [College of Chemistry, Jilin University, Jiefang Road 2519, Changchun 130023 (China); Zou, Yongcun [State Key Laboratory of Inoranic Synthesis and Preparative Chemistryg, College of Chemistry, Jilin University, Changchun 130012 (China); Wu, Shujie; Liu, Heng [College of Chemistry, Jilin University, Jiefang Road 2519, Changchun 130023 (China); Guan, Jingqi, E-mail: guanjq@jlu.edu.cn [College of Chemistry, Jilin University, Jiefang Road 2519, Changchun 130023 (China); Kan, Qiubin, E-mail: qkan@jlu.edu.cn [College of Chemistry, Jilin University, Jiefang Road 2519, Changchun 130023 (China)

2011-06-15

Graphical abstract: A novel and efficient method has been developed for the synthesis of acid-base bifunctional catalyst. The obtained sample of SO{sub 3}H-MCM-41-NH{sub 2} containing amine and sulfonic acids exhibits excellent catalytic activity in aldol condensation reaction. Research highlights: {yields} Synthesize acid-base bifunctional mesoporous materials SO{sub 3}H-MCM-41-NH{sub 2}. {yields} Oxidation and then thermolysis to generate acidic site and basic site. {yields} Exhibit good catalytic performance in aldol condensation reaction between acetone and various aldehydes. -- Abstract: A novel and efficient method has been developed for the synthesis of acid-base bifunctional catalyst SO{sub 3}H-MCM-41-NH{sub 2}. This method was achieved by co-condensation of tetraethylorthosilicate (TEOS), 3-mercaptopropyltrimethoxysilane (MPTMS) and (3-triethoxysilylpropyl) carbamicacid-1-methylcyclohexylester (3TAME) in the presence of cetyltrimethylammonium bromide (CTAB), followed by oxidation and then thermolysis to generate acidic site and basic site. X-ray diffraction (XRD) and transmission electron micrographs (TEM) show that the resultant materials keep mesoporous structure. Thermogravimetric analysis (TGA), X-ray photoelectron spectra (XPS), back titration, solid-state {sup 13}C CP/MAS NMR and solid-state {sup 29}Si MAS NMR confirm that the organosiloxanes were condensed as a part of the silica framework. The bifunctional sample (SO{sub 3}H-MCM-41-NH{sub 2}) containing amine and sulfonic acids exhibits excellent acid-basic properties, which make it possess high activity in aldol condensation reaction between acetone and various aldehydes.

Oxidative stability of milk drinks containing structured lipids produced from sunflower oil and caprylic acid

DEFF Research Database (Denmark)

Timm Heinrich, Maike; Xu, Xuebing; Nielsen, Nina Skall

2003-01-01

Milk drinks containing 5% traditional sunflower oil (SO), randomized lipid (RL) or specific structured lipid (SL) (both produced from SO and tricaprylin/caprylic acid) were compared with respect to their particle size, viscosity and oxidative stability during storage. Furthermore, the effect...... drink could not be ascribed was most likely influenced by the structure of the lipid and to a single factor, differences in the process applied to produce and purify the lipids. EDTA was a strong antioxidant, while gallic acid did not exert a distinct antioxidative effect in the milk drink based on SL....... of adding potential antioxidants EDTA or gallic acid to the milk drink based on SL was investigated. The lipid type significantly affected the oxidative stability of the milk drinks: Milk drink based on SL oxidized faster than milk drink based on RL or SO. The reduced oxidative stability in the SL milk...

Characterization of products from pyrolysis of coal with the addition of polyethylene terephthalate

Czech Academy of Sciences Publication Activity Database

Havelcová, Martina; Bičáková, Olga; Sýkorová, Ivana; Weishauptová, Zuzana; Melegy, A.

2016-01-01

Roč. 154, DEC 15 (2016), 123-131 ISSN 0378-3820 R&D Projects: GA ČR(CZ) GA13-18482S Grant - others:OPPK(XE) CZ.2.16/3.1.00/21538 Program:OPPK Institutional support: RVO:67985891 Keywords : pyrolysis * sub-bituminous coal * polyethylene terephthalate * coke Subject RIV: DD - Geochemistry Impact factor: 3.752, year: 2016

Anodic oxidation of salicylic acid on BDD electrode: Variable effects and mechanisms of degradation

Energy Technology Data Exchange (ETDEWEB)

Rabaaoui, Nejmeddine, E-mail: chimie_tunisie@yahoo.fr [Faculte des Sciences de Sfax, Departement de Chimie, 3038 Sfax (Tunisia); Allagui, Mohamed Salah [Faculte des Sciences de Gafsa, Campus Universitaire Sidi Ahmed Zarrouk, 2112 Gafsa (Tunisia)

2012-12-15

Highlights: Black-Right-Pointing-Pointer Oxidation with BDD is a powerful electrochemical method able to mineralize. Black-Right-Pointing-Pointer SA is oxidized to aromatic compounds then CO{sub 2} and H{sub 2}O. Black-Right-Pointing-Pointer Polymeric intermediate products were formed. - Abstract: The degradation of 100 mL of solution with salicylic acid (SA) in the pH range 3.0-10.0 has been studied by anodic oxidation in a cell with a boron-doped diamond (BDD) anode and a stainless steel cathode, both of 3 cm{sup 2} area, by applying a current of 100, 300 and 450 mA at 25 Degree-Sign C. Completed mineralization is always achieved due to the great concentration of hydroxyl radical ({center_dot}OH) generated at the BDD surface. The mineralization rate increases with increasing applied current, but decreases when drug concentration rises from 200 mg L{sup -1}. Nevertheless, the pH effect was not significant. During oxidation it was observed that catechol, 2,5-dihydroxylated benzoic acid, 2,3-dihydroxylated benzoic acid and hydroquinone were formed as aromatic intermediates. In addition, ion-exclusion chromatography allowed the detection of fumaric, maleic, oxalic and formic as the ultimate carboxylic acid.

Pulsed laser deposition of transparent conductive oxide thin films on flexible substrates

Science.gov (United States)

Socol, G.; Socol, M.; Stefan, N.; Axente, E.; Popescu-Pelin, G.; Craciun, D.; Duta, L.; Mihailescu, C. N.; Mihailescu, I. N.; Stanculescu, A.; Visan, D.; Sava, V.; Galca, A. C.; Luculescu, C. R.; Craciun, V.

2012-11-01

The influence of target-substrate distance during pulsed laser deposition of indium zinc oxide (IZO), indium tin oxide (ITO) and aluminium-doped zinc oxide (AZO) thin films grown on polyethylene terephthalate (PET) substrates was investigated. It was found that the properties of such flexible transparent conductive oxide (TCO)/PET electrodes critically depend on this parameter. The TCO films that were deposited at distances of 6 and 8 cm exhibited an optical transmittance higher than 90% in the visible range and electrical resistivities around 5 × 10-4 Ω cm. In addition to these excellent electrical and optical characteristics the films grown at 8 cm distance were homogenous, smooth, adherent, and without cracks or any other extended defects, being suitable for opto-electronic device applications.

Selective oxidation of glycerol to formic acid in highly concentrated aqueous solutions with molecular oxygen using V-substituted phosphomolybdic acids

KAUST Repository

Zhang, Jizhe; Sun, Miao; Han, Yu

2014-01-01

Formic acid is an important commodity chemical as well as a promising medium for hydrogen storage and hydrogen production. In this paper, we report that formic acid can be produced through selective oxidation of glycerol, a low-cost by-product

Defects in muscle branched-chain amino acid oxidation contribute to impaired lipid metabolism

Directory of Open Access Journals (Sweden)

Carles Lerin

2016-10-01

Full Text Available Objective: Plasma levels of branched-chain amino acids (BCAA are consistently elevated in obesity and type 2 diabetes (T2D and can also prospectively predict T2D. However, the role of BCAA in the pathogenesis of insulin resistance and T2D remains unclear. Methods: To identify pathways related to insulin resistance, we performed comprehensive gene expression and metabolomics analyses in skeletal muscle from 41 humans with normal glucose tolerance and 11 with T2D across a range of insulin sensitivity (SI, 0.49 to 14.28. We studied both cultured cells and mice heterozygous for the BCAA enzyme methylmalonyl-CoA mutase (Mut and assessed the effects of altered BCAA flux on lipid and glucose homeostasis. Results: Our data demonstrate perturbed BCAA metabolism and fatty acid oxidation in muscle from insulin resistant humans. Experimental alterations in BCAA flux in cultured cells similarly modulate fatty acid oxidation. Mut heterozygosity in mice alters muscle lipid metabolism in vivo, resulting in increased muscle triglyceride accumulation, increased plasma glucose, hyperinsulinemia, and increased body weight after high-fat feeding. Conclusions: Our data indicate that impaired muscle BCAA catabolism may contribute to the development of insulin resistance by perturbing both amino acid and fatty acid metabolism and suggest that targeting BCAA metabolism may hold promise for prevention or treatment of T2D. Keywords: Insulin sensitivity, BCAA, Fatty acid oxidation, TCA cycle

78 FR 48651 - Polyethylene Terephthalate Film, Sheet, and Strip From Taiwan; Preliminary Results of Antidumping...

Science.gov (United States)

2013-08-09

... duty order on polyethylene terephthalate film, sheet, and strip (PET Film) from Taiwan. The period of.... (SMTC) (collectively, Shinkong), producer and exporter of PET Film from Taiwan. The Department...: Milton Koch, AD/CVD Operations, Office 6, Import Administration, International Trade Administration, U.S...

Morphology and thermal properties of recycled polyacrylonitrile fiber blends with poly(ethylene terephthalate): Microstructural characterization

CSIR Research Space (South Africa)

Adegbola, TA

2016-04-01

Full Text Available The compounding of rPAN/PET [polyacrylonitrile/poly(ethylene terephthalate]; 30/70, 50/50, and 70/30 wt %) using a melt-blending technique was the main focus of this investigation. An X-ray diffraction study indicated the possibility of interphase...

Effect of ascorbic and folic acids supplementation on oxidative ...

African Journals Online (AJOL)

An experiment was conducted on the effect of supplementation of ascorbic and folic acids on the oxidative hormones, enzymatic antioxidants, haematological and biochemical properties of layers exposed to increased heat load. A total of 72 Isa Brown laying hens at 31 weeks of age were randomly divided into four groups ...

Impacts of acid gases on mercury oxidation across SCR catalyst

International Nuclear Information System (INIS)

Zhuang, Ye; Laumb, Jason; Liggett, Richard; Holmes, Mike; Pavlish, John

2007-01-01

A series of bench-scale experiments were completed to evaluate acid gases of HCl, SO 2 , and SO 3 on mercury oxidation across a commercial selective catalytic reduction (SCR) catalyst. The SCR catalyst was placed in a simulated flue gas stream containing O 2 , CO 2 , H 2 O, NO, NO 2 , and NH 3 , and N 2 . HCl, SO 2 , and SO 3 were added to the gas stream either separately or in combination to investigate their interactions with mercury over the SCR catalyst. The compositions of the simulated flue gas represent a medium-sulfur and low- to medium-chlorine coal that could represent either bituminous or subbituminous. The experimental data indicated that 5-50 ppm HCl in flue gas enhanced mercury oxidation within the SCR catalyst, possibly because of the reactive chlorine species formed through catalytic reactions. An addition of 5 ppm HCl in the simulated flue gas resulted in mercury oxidation of 45% across the SCR compared to only 4% mercury oxidation when 1 ppm HCl is in the flue gas. As HCl concentration increased to 50 ppm, 63% of Hg oxidation was reached. SO 2 and SO 3 showed a mitigating effect on mercury chlorination to some degree, depending on the concentrations of SO 2 and SO 3 , by competing against HCl for SCR adsorption sites. High levels of acid gases of HCl (50 ppm), SO 2 (2000 ppm), and SO 3 (50 ppm) in the flue gas deteriorate mercury adsorption on the SCR catalyst. (author)

Vanadium oxides supported on hydrotalcite-type precursors: the effect of acid-base properties on the oxidation of isopropanol

Directory of Open Access Journals (Sweden)

D. M. Meira

2006-09-01

Full Text Available Vanadium oxide supported on hydrotalcite-type precursors was studied in the oxidation of isopropanol. Hydrotalcites with different y = Mg/Al ratios were synthesized by the method of coprecipitation nitrates of Mg and Al cations with K2CO3 as precipitant. The decomposition of these hydrotalcite precursors at 450°C yielded homogeneous MgyAlOx mixed oxides that contain the Al+3 cations totally incorporated into the MgO framework. The materials were characterized by chemical analysis, BET superficial area, X-ray diffraction, temperature-programmed reduction (TPR and the reaction of isopropanol, a probe molecule used to evaluate the acid-base properties. The results of TPR showed that the reducibility of V+5 decreased with the increase in magnesium loading in catalysts. The X-ray diffraction patterns of Al-rich hydrotalcite precursors showed the presence of crystalline phases of brucite and gibbsite. It was shown that chemical composition, texture, acid-base properties of the active sites and also Mg/Al ratio strongly affect the formation of the products in the oxidation of isopropanol. The Al-rich catalysts were much more active than the Mg-rich ones, converting isopropanol mainly to propylene.

Vanadium oxides supported on hydrotalcite-type precursors: the effect of acid base properties on the oxidation of isopropanol

Energy Technology Data Exchange (ETDEWEB)

Meira, D.M.; Cortez, G.G. [Faculdade de Engenharia Quimica de Lorena, Lorena, SP (Brazil). Dept. de Engenharia Quimica. Lab. de Catalise II]. E-mail: cortez@dequi.faenquil.br; Monteiro, W.R.; Rodrigues, J.A.J. [Instituto Nacional de Pesquisas Espaciais (INPE), Sao Jose dos Campos, SP (Brazil). Lab. Associado de Combustao e Propulsao]. E-mail: jajr@lcp.inpe.br

2006-07-15

Vanadium oxide supported on hydrotalcite-type precursors was studied in the oxidation of isopropanol. Hydrotalcites with different y = Mg/Al ratios were synthesized by the method of coprecipitation nitrates of Mg and Al cations with K{sub 2}CO{sub 3} as precipitant. The decomposition of these hydrotalcite precursors at 450 deg C yielded homogeneous MgyAlOx mixed oxides that contain the Al{sup +3} cations totally incorporated into the MgO framework. The materials were characterized by chemical analysis, BET superficial area, X-ray diffraction, temperature-programmed reduction (TPR) and the reaction of isopropanol, a probe molecule used to evaluate the acid-base properties. The results of TPR showed that the reducibility of V{sup +5} decreased with the increase in magnesium loading in catalysts. The X-ray diffraction patterns of Al-rich hydrotalcite precursors showed the presence of crystalline phases of brucite and gibbsite. It was shown that chemical composition, texture, acid-base properties of the active sites and also Mg/Al ratio strongly affect the formation of the products in the oxidation of isopropanol. The Al-rich catalysts were much more active than the Mg-rich ones, converting isopropanol mainly to propylene. (author)

Reduction Rates for Higher Americium Oxidation States in Nitric Acid

Energy Technology Data Exchange (ETDEWEB)

Grimes, Travis Shane [Idaho National Lab. (INL), Idaho Falls, ID (United States); Mincher, Bruce Jay [Idaho National Lab. (INL), Idaho Falls, ID (United States); Schmitt, Nicholas C [Idaho National Lab. (INL), Idaho Falls, ID (United States)

2015-09-30

The stability of hexavalent americium was measured using multiple americium concentrations and nitric acid concentrations after contact with the strong oxidant sodium bismuthate. Contrary to our hypotheses Am(VI) was not reduced faster at higher americium concentrations, and the reduction was only zero-order at short time scales. Attempts to model the reduction kinetics using zero order kinetic models showed Am(VI) reduction in nitric acid is more complex than the autoreduction processes reported by others in perchloric acid. The classical zero-order reduction of Am(VI) was found here only for short times on the order of a few hours. We did show that the rate of Am(V) production was less than the rate of Am(VI) reduction, indicating that some Am(VI) undergoes two electron-reduction to Am(IV). We also monitored the Am(VI) reduction in contact with the organic diluent dodecane. A direct comparison of these results with those in the absence of the organic diluent showed the reduction rates for Am(VI) were not statistically different for both systems. Additional americium oxidations conducted in the presence of Ce(IV)/Ce(III) ions showed that Am(VI) is reduced without the typical growth of Am(V) observed in the systems sans Ce ion. This was an interesting result which suggests a potential new reduction/oxidation pathway for Am in the presence of Ce; however, these results were very preliminary, and will require additional experiments to understand the mechanism by which this occurs. Overall, these studies have shown that hexavalent americium is fundamentally stable enough in nitric acid to run a separations process. However, the complicated nature of the reduction pathways based on the system components is far from being rigorously understood.

An innovative zinc oxide-coated zeolite adsorbent for removal of humic acid

Science.gov (United States)

Zinc oxide (ZnO)-coated zeolite adsorbents were developed by both nitric acid modification and Zn(NO3)2•6H2O functionalization of zeolite. The developed adsorbents were used for the removal of humic acid (HA) from aqueous solutions. The adsorption capacity of the adsorbents at 21...

Linoleic acid participates in the response to ischemic brain injury through oxidized metabolites that regulate neurotransmission.

Science.gov (United States)

Hennebelle, Marie; Zhang, Zhichao; Metherel, Adam H; Kitson, Alex P; Otoki, Yurika; Richardson, Christine E; Yang, Jun; Lee, Kin Sing Stephen; Hammock, Bruce D; Zhang, Liang; Bazinet, Richard P; Taha, Ameer Y

2017-06-28

Linoleic acid (LA; 18:2 n-6), the most abundant polyunsaturated fatty acid in the US diet, is a precursor to oxidized metabolites that have unknown roles in the brain. Here, we show that oxidized LA-derived metabolites accumulate in several rat brain regions during CO 2 -induced ischemia and that LA-derived 13-hydroxyoctadecadienoic acid, but not LA, increase somatic paired-pulse facilitation in rat hippocampus by 80%, suggesting bioactivity. This study provides new evidence that LA participates in the response to ischemia-induced brain injury through oxidized metabolites that regulate neurotransmission. Targeting this pathway may be therapeutically relevant for ischemia-related conditions such as stroke.

Arachidonic acid triggers an oxidative burst in leukocytes

Directory of Open Access Journals (Sweden)

Pompeia C.

2003-01-01

Full Text Available The change in cellular reducing potential, most likely reflecting an oxidative burst, was investigated in arachidonic acid- (AA stimulated leukocytes. The cells studied included the human leukemia cell lines HL-60 (undifferentiated and differentiated into macrophage-like and polymorphonuclear-like cells, Jurkat and Raji, and thymocytes and macrophages from rat primary cultures. The oxidative burst was assessed by nitroblue tetrazolium reduction. AA increased the oxidative burst until an optimum AA concentration was reached and the burst decreased thereafter. In the leukemia cell lines, optimum concentration ranged from 200 to 400 µM (up to 16-fold, whereas in rat cells it varied from 10 to 20 µM. Initial rates of superoxide generation were high, decreasing steadily and ceasing about 2 h post-treatment. The continuous presence of AA was not needed to stimulate superoxide generation. It seems that the NADPH oxidase system participates in AA-stimulated superoxide production in these cells since the oxidative burst was stimulated by NADPH and inhibited by N-ethylmaleimide, diphenyleneiodonium and superoxide dismutase. Some of the effects of AA on the oxidative burst may be due to its detergent action. There apparently was no contribution of other superoxide-generating systems such as xanthine-xanthine oxidase, cytochromes P-450 and mitochondrial electron transport chain, as assessed by the use of inhibitors. Eicosanoids and nitric oxide also do not seem to interfere with the AA-stimulated oxidative burst since there was no systematic effect of cyclooxygenase, lipoxygenase or nitric oxide synthase inhibitors, but lipid peroxides may play a role, as indicated by the inhibition of nitroblue tetrazolium reduction promoted by tocopherol.

Oxidation kinetics of crystal violet by potassium permanganate in acidic medium

Science.gov (United States)

Khan, Sameera Razi; Ashfaq, Maria; Mubashir; Masood, Summyia

2016-05-01

The oxidation kinetics of crystal violet (a triphenylmethane dye) by potassium permanganate was focused in an acidic medium by the spectrophotometric method at 584 nm. The oxidation reaction of crystal violet by potassium permanganate is carried out in an acidic medium at different temperatures ranging within 298-318 K. The kinetic study was carried out to investigate the effect of the concentration, ionic strength and temperature. The reaction followed first order kinetics with respect to potassium permanganate and crystal violet and the overall rate of the reaction was found to be second order. Thermodynamic activation parameters like the activation energy ( E a), enthalpy change (Δ H*), free energy change (Δ G*), and entropy change (Δ S*) have also been evaluated.

Mesoporous Nb and Ta Oxides: Synthesis, Characterization and Applications in Heterogeneous Acid Catalysis

Science.gov (United States)

Rao, Yuxiang Tony

In this work, a series of mesoporous Niobium and Tantalum oxides with different pore sizes (C6, C12, C18 , ranging from 12A to 30 A) were synthesized using the ligand-assisted templating approach and investigated for their activities in a wide range of catalytic applications including benzylation, alkylation and isomerization. The as-synthesized mesoporous materials were characterized by nitrogen adsorption, powder X-ray diffraction, transmission electron microscopy (TEM), scanning electron microscopy (SEM), thermo gravimetric analysis (TGA), differential scanning calorimetry (DSC), and solid-state Nuclear magnetic resonance (NMR) techniques. In order to probe into the structural and coordination geometry of mesoporous Nb oxide and in efforts to make meaningful comparisons of mesoporous niobia prepared by the amine-templating method with the corresponding bulk sol-gel prepared Nb2O5 phase, 17O magic-angle-spinning solid-state NMR studies were conducted. The results showed a very high local order in the mesoporous sample. The oxygen atoms are coordinated only as ONb 2 in contrast with bulk phases in which the oxygen atoms are always present in a mixture of ONb2 and ONb3 coordination environments. To enhance their surface acidities and thus improve their performance as solid acid catalysts in the acid-catalyzed reactions mentioned above, pure mesoporous Nb and Ta oxides were further treated with 1M sulfuric acid or phosphoric acid. Their surface acidities before and after acid treatment were measured by Fourier transform infraRed (FT IR), amine titration and temperature programmed desorption of ammonia (NH3-TPD). Results obtained in this study showed that sulfated mesoporous Nb and Ta oxides materials possess relative high surface areas (up to 612 m 2/g) and amorphous wormhole structure. These mesoporous structures are thus quite stable to acid treatment. It was also found that Bronsted (1540 cm-1) and Lewis (1450 cm-1) acid sites coexist in a roughly 50:50 mixture

Pros and cons of analytical methods to quantify surrogate contaminants from the challenge test in recycled polyethylene terephthalate

Energy Technology Data Exchange (ETDEWEB)

Felix, Juliana S., E-mail: jfelix@unizar.es [Department of Analytical Chemistry, Aragon Institute of Engineering Research (I3A), CPS, University of Zaragoza, Torres Quevedo Bldg., Maria de Luna St. 3, E-50018 Zaragoza (Spain); Alfaro, Pilar, E-mail: palfarot@unizar.es [Department of Analytical Chemistry, Aragon Institute of Engineering Research (I3A), CPS, University of Zaragoza, Torres Quevedo Bldg., Maria de Luna St. 3, E-50018 Zaragoza (Spain); Nerin, Cristina, E-mail: cnerin@unizar.es [Department of Analytical Chemistry, Aragon Institute of Engineering Research (I3A), CPS, University of Zaragoza, Torres Quevedo Bldg., Maria de Luna St. 3, E-50018 Zaragoza (Spain)

2011-02-14

Different analytical methods were optimized and applied to quantify certain surrogate contaminants (toluene, chlorobenzene, phenol, limonene and benzophenone) in samples of contaminated and recycled flakes and virgin pellets of polyethylene terephthalate (PET) coming from the industrial challenge test. A screening analysis of the PET samples was carried out by direct solid-phase microextraction (SPME) in headspace mode (HS). The methods developed and used for quantitative analysis were a) total dissolution of PET samples in dichloroacetic acid and analysis by HS-SPME coupled to gas chromatography-mass spectrometry (GC-MS) and, b) dichloromethane extraction and analysis by GC-MS. The concentration of all surrogates in the contaminated PET flakes analyzed by HS-SPME method was lower than expected according to information provided by the supplier. Dichloroacetic acid interacted with the surrogates, resulting in a tremendous decrease of limonene concentration. The degradation compounds from limonene were identified. Dichloromethane extraction and GC-MS analysis evidenced the highest values of analytes in these PET samples. Based on the foregoing data, the efficiency of the recycling process was evaluated, whereby the removal of 99.9% of the surrogates proceeding from the contaminated flakes was confirmed.

Pros and cons of analytical methods to quantify surrogate contaminants from the challenge test in recycled polyethylene terephthalate

International Nuclear Information System (INIS)

Felix, Juliana S.; Alfaro, Pilar; Nerin, Cristina

2011-01-01

Different analytical methods were optimized and applied to quantify certain surrogate contaminants (toluene, chlorobenzene, phenol, limonene and benzophenone) in samples of contaminated and recycled flakes and virgin pellets of polyethylene terephthalate (PET) coming from the industrial challenge test. A screening analysis of the PET samples was carried out by direct solid-phase microextraction (SPME) in headspace mode (HS). The methods developed and used for quantitative analysis were a) total dissolution of PET samples in dichloroacetic acid and analysis by HS-SPME coupled to gas chromatography-mass spectrometry (GC-MS) and, b) dichloromethane extraction and analysis by GC-MS. The concentration of all surrogates in the contaminated PET flakes analyzed by HS-SPME method was lower than expected according to information provided by the supplier. Dichloroacetic acid interacted with the surrogates, resulting in a tremendous decrease of limonene concentration. The degradation compounds from limonene were identified. Dichloromethane extraction and GC-MS analysis evidenced the highest values of analytes in these PET samples. Based on the foregoing data, the efficiency of the recycling process was evaluated, whereby the removal of 99.9% of the surrogates proceeding from the contaminated flakes was confirmed.

10-Oxo-trans-11-octadecenoic acid generated from linoleic acid by a gut lactic acid bacterium Lactobacillus plantarum is cytoprotective against oxidative stress.

Science.gov (United States)

Furumoto, Hidehiro; Nanthirudjanar, Tharnath; Kume, Toshiaki; Izumi, Yasuhiko; Park, Si-Bum; Kitamura, Nahoko; Kishino, Shigenobu; Ogawa, Jun; Hirata, Takashi; Sugawara, Tatsuya

2016-04-01

Oxidative stress is a well-known cause of multiple diseases. The nuclear factor erythroid 2-related factor 2 (Nrf2)-antioxidant response element (ARE) pathway plays a central role in cellular antioxidative responses. In this study, we investigated the effects of novel fatty acid metabolite derivatives of linoleic acid generated by the gut lactic acid bacteria Lactobacillus plantarum on the Nrf2-ARE pathway. 10-Oxo-trans-11-octadecenoic acid (KetoC) protected HepG2 cells from cytotoxicity induced by hydrogen peroxide. KetoC also significantly increased cellular Nrf2 protein levels, ARE-dependent transcription, and the gene expression of antioxidative enzymes such as heme oxygenase-1 (HO-1), glutamate-cysteine ligase modifier subunit (GCLM), and quinone oxidoreductase 1 (NQO1) in HepG2 cells. Additionally, a single oral dose administration of KetoC also increased antioxidative gene expression and protein levels of Nrf2 and HO-1 in mouse organs. Since other fatty acid metabolites and linoleic acid did not affect cellular antioxidative responses, the cytoprotective effect of KetoC may be because of its α,β-unsaturated carbonyl moiety. Collectively, our data suggested that KetoC activated the Nrf2-ARE pathway to enhance cellular antioxidative responses in vitro and in vivo, which further suggests that KetoC may prevent multiple diseases induced by oxidative stress. Copyright © 2016. Published by Elsevier Inc.

Synthesis and characterization of bright green terbium coordination complex derived from 1,4-bis(carbonylmethyl)terephthalate: Structure and luminescence properties

Science.gov (United States)

Ma, Mengjiao; Li, Congcong; Shu, Dengkun; Wang, Chaohua; Xi, Peng

2018-02-01

A photoluminescent terbium (Tb) complex involving a novel benzoic-acid compound with a unique coordinated structure, namely 1,4-bis(carbonylmethyl)terephthalate (BCMT), has been designed and synthesized. The new coordinate structure and energy-transfer mechanism between the ligand and Tb(III) ions were investigated in detail. The results demonstrated that the BCMT-Tb(III) complex shows strong fluorescence intensity (4 × 106 a.u.) and long fluorescence lifetime (1.302 ms), owing to the favorable degree of energy matching between the triplet excited level of the ligand and the resonant level of Tb(III) ions. Based on the analysis of three-dimensional luminescence spectra, the as-prepared Tb(III) complex can be effectively excited in the range of 250-310 nm, and it shows high color purity, with a bright green appearance.

76 FR 30910 - Polyethylene Terephthalate Film, Sheet, and Strip From India: Final Results of Countervailing...

Science.gov (United States)

2011-05-27

... shipper review of polyethylene terephthalate film, sheet and strip (PET Film) from India for SRF Limited... Operations, Office 6, Import Administration, International Trade Administration, U.S. Department of Commerce..., International Trade Compliance Analyst, AD/CVD Operations, Office 6: New Shipper Reviews of the Antidumping Duty...

75 FR 6634 - Polyethylene Terephthalate Film, Sheet, and Strip from India: Final Results of Countervailing...

Science.gov (United States)

2010-02-10

... of the countervailing duty order on polyethylene terephthalate film, sheet, and strip (PET film) from....'' EFFECTIVE DATE: February 10, 2010. FOR FURTHER INFORMATION CONTACT: Elfi Blum, AD/CVD Operations, Office 6... Assistant Secretary for Import Administration, from Barbara E. Tillman, Director, AD/CVD Operations, Office...

78 FR 77649 - Polyethylene Terephthalate Film, Sheet, and Strip From the United Arab Emirates; Preliminary...

Science.gov (United States)

2013-12-24

... Film, Sheet, and Strip From the United Arab Emirates; Preliminary Results of Antidumping Duty... film, sheet, and strip (PET Film) from the United Arab Emirates (UAE). The period of review (POR) is... Administrative Review: Polyethylene Terephthalate Film, Sheet, and Strip from the United Arab Emirates...

Amino acid-assisted synthesis of zinc oxide nanostructures

Science.gov (United States)

Singh, Baljinder; Moudgil, Lovika; Singh, Gurinder; Kaura, Aman

2018-05-01

In this manuscript we have used experimental approach that can provide a fundamental knowledge about the role played by biomolecules in designing the shape of nanostructure (NS) at a microscopic level. The three different amino acids (AAs) - Arginine (Arg), Aspartic acid (Asp) and Histidine (His) coated Zinc oxide (ZnO) NSs to explain the growth mechanism of nanoparticles of different shapes. Based on the experimental methodology we propose that AA-ZnO (Asp and Arg) nanomaterials could form of rod like configuration and His-ZnO NPs could form tablet like configuration. The synthesized samples are characterized using transmission electron microscopy (TEM) and X-ray diffraction (XRD). Results reveal that AAs are responsible for formation of different NSs

Unusual differences in the reactivity of glutamic and aspartic acid in oxidative decarboxylation reactions

NARCIS (Netherlands)

But, Andrada; Wijst, van der Evie; Notre, le Jerome; Wever, Ron; Sanders, Johan P.M.; Bitter, Johannes H.; Scott, Elinor L.

2017-01-01

Amino acids are potential substrates to replace fossil feedstocks for the synthesis of nitriles via oxidative decarboxylation using vanadium chloroperoxidase (VCPO), H₂O₂ and bromide. Here the conversion of glutamic acid (Glu) and aspartic acid (Asp) was investigated. It was

Graphitic carbon nitride nanosheets doped graphene oxide for electrochemical simultaneous determination of ascorbic acid, dopamine and uric acid

International Nuclear Information System (INIS)

Zhang, Hanqiang; Huang, Qitong; Huang, Yihong; Li, Feiming; Zhang, Wuxiang; Wei, Chan; Chen, Jianhua; Dai, Pingwang; Huang, Lizhang; Huang, Zhouyi; Kang, Lianping; Hu, Shirong; Hao, Aiyou

2014-01-01

Graphical abstract: Schematic drawing of electrochemical oxidize AA, DA and UA on graphitic carbon nitride nanosheets-graphene oxide composite modified electrode. - Highlights: • Synthesize g-C 3 N 4 , GO and CNNS-GO composite. • CNNS-GO composite was the first time for simultaneous determination of AA, DA and UA. • CNNS-GO/GCE displays fantastic selectivity and sensitivity for AA, DA and UA. • CNNS-GO/GCE was applied to detect real sample with satisfactory results. - Abstract: Graphitic carbon nitride nanosheets with a graphite-like structure have strong covalent bonds between carbon and nitride atoms, and nitrogen atoms in the carbon architecture can accelerate the electron transfer and enhance electrical properties effectually. The graphitic carbon nitride nanosheets-graphene oxide composite was synthesized. And the electrochemical performance of the composite was investigated by cyclic voltammetry and differential pulse voltammetry ulteriorly. Due to the synergistic effects of layer-by-layer structures by π-π stacking or charge-transfer interactions, graphitic carbon nitride nanosheets-graphene oxide composite can improved conductivity, electro-catalytic and selective oxidation performance. The proposed graphitic carbon nitride nanosheets-graphene oxide composite modified electrode was employed for simultaneous determination of ascorbic acid, dopamine and uric acid in their mixture solution, it exhibited distinguished sensitivity, wide linear range and low detection limit. Moreover, the modified electrode was applied to detect urine and dopamine injection sample, and then the samples were spiked with certain concentration of three substances with satisfactory recovery results

Optimization of the p-xylene oxidation process by a multi-objective differential evolution algorithm with adaptive parameters co-derived with the population-based incremental learning algorithm

Science.gov (United States)

Guo, Zhan; Yan, Xuefeng

2018-04-01

Different operating conditions of p-xylene oxidation have different influences on the product, purified terephthalic acid. It is necessary to obtain the optimal combination of reaction conditions to ensure the quality of the products, cut down on consumption and increase revenues. A multi-objective differential evolution (MODE) algorithm co-evolved with the population-based incremental learning (PBIL) algorithm, called PBMODE, is proposed. The PBMODE algorithm was designed as a co-evolutionary system. Each individual has its own parameter individual, which is co-evolved by PBIL. PBIL uses statistical analysis to build a model based on the corresponding symbiotic individuals of the superior original individuals during the main evolutionary process. The results of simulations and statistical analysis indicate that the overall performance of the PBMODE algorithm is better than that of the compared algorithms and it can be used to optimize the operating conditions of the p-xylene oxidation process effectively and efficiently.