WorldWideScience

Sample records for single hydroxyl group

  1. Infrared absorption characteristics of hydroxyl groups in coal tars

    Energy Technology Data Exchange (ETDEWEB)

    Cannon, S A; Chu, C J; Hange, R H; Margrave, J L

    1987-01-01

    Tar evolution was observed over a temperature range of 150-600 C for four coals. Pittsburgh bituminous, Illinois No.6, Rawhide subbituminous, and Texas lignite. Isolation of the evolved tars in a nitrogen matrix at 15 degrees K produced better resolved infrared spectra than those in a coal matrix, thus enhancing structural characterization of the tar molecules. Two distinct hydroxyl functional groups in the tar molecules free of hydrogen bonding were identified for the first time without interference from H/sub 2/O absorptions. These absorptions at 3626.5 cm/sup -1/ have been assigned to phenolic hydroxyls. It is suggested that carboxylic and aliphatic hydroxyl groups do not survive the vaporization process. Tars from Illinois No.6 were found to contain the largest amount of phenolic hydroxyl; Pittsburgh No. 8 tar contains approximately half of that for Illinois No.6 while Rawhide and Texas lignite contain much less phenolic than either of the other coals. 10 references, 6 figures, 1 table.

  2. [Epimerization of hydroxyl group in the lupan series of triterpenes].

    Science.gov (United States)

    Symon, A V; Kaplun, A P; Vlasenkova, N K; Gerasimova, G K; Shon, Le Bang; Litvin, E F; Kozlova, L M; Surkova, E L; Shvets, V I

    2003-01-01

    Two methods of obtaining of 3 alpha-betulinic acid and related compounds from their 3 beta-epimers were studied: the reaction of bimolecular substitution and the stereoselective reduction of 3-ketoderivatives. The substitution of acyloxy by formyloxy group in 3-O-tosyllupeol or of the betulin hydroxyl by benzoyloxy group resulted only in delta 2, 3-elimination products, with none of the expected products of bimolecular substitution being found. The catalytic hydrogenation of betulonic acid over Raney nickel resulted only in reduction of the isopropenyl double bond, whereas the use of 5% Ru/C gave a 60:40 mixture of epimers of dihydrobetulinic acid. Practically the same mixture of betulinic acid epimers was obtained when reducing betulonic acid with L-Selectride. The cytotoxic activity of 3 alpha-betulinic acid increased toward melanoma Bro cells and decreased toward melanoma MS cells.

  3. Tuning the Slide-Roll Motion Mode of Carbon Nanotubes via Hydroxyl Groups

    Science.gov (United States)

    Li, Rui; Wang, Shiwei; Peng, Qing

    2018-05-01

    Controlling the motion of carbon nanotubes is critical in manipulating nanodevices, including nanorobots. Herein, we investigate the motion behavior of SWCNT (10,10) on Si substrate utilizing molecular dynamics simulations. We show that hydroxyl groups have sensitive effect on the carbon nanotube's motion mode. When the hydroxyl groups' ratio on carbon nanotube and silicon substrate surfaces is larger than 10 and 20%, respectively, the motion of carbon nanotube transforms from sliding to rolling. When the hydroxyl groups' ratio is smaller, the slide or roll mode can be controlled by the speed of carbon nanotube, which is ultimately determined by the competition between the interface potential energy and kinetic energy. The change of motion mode holds true for different carbon nanotubes with hydroxyl groups. The chirality has little effect on the motion behavior, as opposed to the diameter, attributed to the hydroxyl groups' ratio. Our study suggests a new route to control the motion behavior of carbon nanotube via hydroxyl groups.

  4. Electrolytic coloration and spectral properties of hydroxyl-doped potassium chloride single crystals

    International Nuclear Information System (INIS)

    Gu Hongen; Wu Yanru

    2011-01-01

    Hydroxyl-doped potassium chloride single crystals are colored electrolytically at various temperatures and voltages using a pointed cathode and a flat anode. Characteristic OH - spectral band is observed in the absorption spectrum of uncolored single crystal. Characteristic O - , OH - , U, V 2 , V 3 , O 2- -V a + , F, R 2 and M spectral bands are observed simultaneously in absorption spectra of colored single crystals. Current-time curve for electrolytic coloration of hydroxyl-doped potassium chloride single crystal and its relationship with electrolytic coloration process are given. Production and conversion of color centers are explained. - Highlights: → Expanded the traditional electrolysis method. → Hydroxyl-doped potassium chloride crystals were colored electrolytically for the first time. → Useful V, F and F-aggregate color centers were produced in colored crystals. → V color centers were produced directly and F and F-aggregate color centers indirectly.

  5. Hydrogen bonding analysis of hydroxyl groups in glucose aqueous solutions by a molecular dynamics simulation study

    International Nuclear Information System (INIS)

    Chen, Cong; Li, Wei Zhong; Song, Yong Chen; Weng, Lin Dong; Zhang, Ning

    2012-01-01

    Molecular dynamics simulations have been performed to investigate hydrogen bonding characteristics of hydroxyl groups in glucose aqueous solutions with different concentrations. The hydrogen bonding abilities and strength of different O and H atom types have been calculated and compared. The acceptor/donor efficiencies have been predicted and it has been found that: (1) O2-HO2 and O3-HO3 are more efficient intramolecular hydrogen bonding acceptors than donors; (2) O1-HO1, O4-HO4 and O6-HO6 are more efficient intramolecular hydrogen bonding donors than acceptors; (5) O1-HO1 and O6-HO6 are more efficient intermolecular hydrogen bonding acceptors than donors while hydroxyl groups O2-HO2 and O4-HO4 are more efficient intermolecular hydrogen bonding donors than acceptors. The hydrogen bonding abilities of hydroxyl groups revealed that: (1) the hydrogen bonding ability of OH2-H w is larger than that of hydroxyl groups in glucose; (2) among the hydroxyl groups in glucose, the hydrogen bonding ability of O6-HO6 is the largest and the hydrogen bonding ability of O4-HO4 is the smallest; (3) the intermolecular hydrogen bonding ability of O6-HO6 is the largest; (4) the order for intramolecular hydrogen bonding abilities (from large to small) is O2-HO2, O1-HO1, O3-HO3, O6-HO6 and O4-HO4

  6. On the nature of the electronic effect of multiple hydroxyl groups in the 6-membered ring - the effects are additive but steric hindrance plays a role too

    DEFF Research Database (Denmark)

    Pedersen, Christian Marcus; Bols, Mikael

    2017-01-01

    Research during the last two decades has shown a remarkable directional component of the substituent effects of hydroxy groups, which has a profound effect on the properties of hydroxylated compounds such as carbohydrates. While the epimerisation of a single hydroxyl function is well studied...... synthesized and their pKa and conformation were studied. The results show that the large difference in the electronic effect between the axial and equatorial hydroxyls is partially cancelled by counteracting steric hindrance from 1,3-diaxial interactions. Hydrogen bonding does not appear to play any role...

  7. Hydrotreating of compounds and mixtures of compounds having mercapto and hydroxyl groups

    Energy Technology Data Exchange (ETDEWEB)

    Viljava, T.R.; Krause, A.O.I. [Helsinki University of Technology, Espoo (Finland)

    1997-07-01

    Simultaneous hydrodesulfurization (HDS) and hydrodeoxygenation (HDO) of mercapto and hydroxyl group containing benzenes was studied using a commercial presulfided CoMo/{gamma}- Al{sub 2}O{sub 3} catalyst under hydrotreating conditions (150-280 deg C, 7 MPa). Mercaptobenzene, phenol and 4-mercaptophenol were used as model compounds, and CS{sub 2} was used as precursor for H{sub 2}S. The HDS rate of a mercapto group in the presence of a hydroxyl substituent in the para position was higher than that for the molecule containing only a mercapto group. When the hydroxyl group was present as phenol, the HDS rate of the mercapto group was about 30% lower than that for mercaptobenzene without an oxygen-containing additive. The decrease in the HDS rate was independent of the initial molar ratio of sulfur and oxygen within the ratios studied (5:1-1:1). The HDO rate of a hydroxyl group was suppressed by the mercapto group present either in the same or in a separate molecule. HDO reactions did not start until HDS conversion was almost complete. CS{sub 2} also decreased the HDO rate of phenol. When compared to the reactions of phenol alone, the rate of the hydrogenolysis route to benzene was decreased in the presence of a sulfur additive more than the hydrogenolysis- hydrogenation route to cyclohexane. 19 refs.

  8. Electrolytic coloration and spectral properties of hydroxyl-doped potassium bromide single crystals

    International Nuclear Information System (INIS)

    Qi, Lan; Song, Cuiying; Gu, Hongen

    2013-01-01

    Hydroxyl-doped potassium bromide single crystals are colored electrolytically at various temperatures and voltages by using a pointed cathode and a flat anode. The characteristic OH − spectral band is observed in absorption spectrum of uncolored single crystal. The characteristic O − , OH − , U, V 2 , O 2− −V a + , M L1 , F and M spectral bands are observed simultaneously in absorption spectra of colored single crystals. Current–time curve for electrolytic coloration of hydroxyl-doped potassium bromide single crystal and its relationship with electrolytic coloration processes are given. Production and conversion of color centers are explained. - Highlights: ► We expanded the traditional electrolysis method. ► Hydroxyl-doped potassium bromide crystals were colored electrolytically for the first time. ► Useful V, F and F-aggregate color centers were produced in colored crystals. ► V color centers were produced directly and F as well as F-aggregate color centers indirectly.

  9. Reaction of single-standard DNA with hydroxyl radical generated by iron(II)-ethylenediaminetetraacetic acid

    International Nuclear Information System (INIS)

    Prigodich, R.V.; Martin, C.T.

    1990-01-01

    This study demonstrates that the reaction of Fe(II)-EDTA and hydrogen peroxide with the single-stranded nucleic acids d(pT) 70 and a 29-base sequence containing a mixture of bases results in substantial damage which is not directly detected by gel electrophoresis. Cleavage of the DNA sugar backbone is enhanced significantly after the samples are incubated at 90 degree C in the presence of piperidine. The latter reaction is used in traditional Maxam-Gilbert DNA sequencing to detect base damage, and the current results are consistent with reaction of the hydroxyl radical with the bases in single-stranded DNA (although reaction with sugar may also produce adducts that are uncleaved but labile to cleavage by piperidine). We the authors propose that hydroxyl radicals may react preferentially with the nucleic acid bases in ssDNA and that reaction of the sugars in dsDNA is dominant because the bases are sequestered within the double helix. These results have implications both for the study of single-stranded DNA binding protein binding sites and for the interpretation of experiments using the hydroxyl radical to probe DNA structure or to footprint double-stranded DNA binding protein binding sites

  10. Monolayer arrangement of fatty hydroxystearic acids on graphite: Influence of hydroxyl groups

    Energy Technology Data Exchange (ETDEWEB)

    Medina, S. [Laboratorio de Rayos-X, Centro de Investigación Tecnología e Innovación, de la Universidad de Sevilla (CITIUS), Universidad de Sevilla, Avenida Reina Mercedes, 4B. 41012, Sevilla (Spain); Benítez, J.J.; Castro, M.A. [Instituto de Ciencia de Materiales de Sevilla, Consejo Superior de Investigaciones Científicas-Universidad de Sevilla, Avenida Américo Vespucio, 49. 41092, Sevilla (Spain); Cerrillos, C. [Servicio de Microscopía, Centro de Investigación Tecnología e Innovación, de la Universidad de Sevilla (CITIUS), Universidad de Sevilla, Avenida Reina Mercedes, 4B. 41012, Sevilla (Spain); Millán, C. [Instituto de Ciencia de Materiales de Sevilla, Consejo Superior de Investigaciones Científicas-Universidad de Sevilla, Avenida Américo Vespucio, 49. 41092, Sevilla (Spain); Alba, M.D., E-mail: alba@icmse.csic.es [Instituto de Ciencia de Materiales de Sevilla, Consejo Superior de Investigaciones Científicas-Universidad de Sevilla, Avenida Américo Vespucio, 49. 41092, Sevilla (Spain)

    2013-07-31

    Previous studies have indicated that long-chain linear carboxylic acids form commensurate packed crystalline monolayers on graphite even at temperatures above their melting point. This study examines the effect on the monolayer formation and structure of adding one or more secondary hydroxyl, functional groups to the stearic acid skeleton (namely, 12-hydroxystearic and 9,10-dihydroxystearic acid). Moreover, a comparative study of the monolayer formation on recompressed and monocrystalline graphite has been performed through X-ray diffraction (XRD) and Scanning Tunneling Microscopy (STM), respectively. The Differential Scanning Calorimetry (DSC) and XRD data were used to confirm the formation of solid monolayers and XRD data have provided a detailed structural analysis of the monolayers in good correspondence with obtained STM images. DSC and XRD have demonstrated that, in stearic acid and 12-hydroxystearic acid adsorbed onto graphite, the monolayer melted at a higher temperature than the bulk form of the carboxylic acid. However, no difference was observed between the melting point of the monolayer and the bulk form for 9,10-dihydroxystearic acid adsorbed onto graphite. STM results indicated that all acids on the surface have a rectangular p2 monolayer structure, whose lattice parameters were uniaxially commensurate on the a-axis. This structure does not correlate with the initial structure of the pure compounds after dissolving, but it is conditioned to favor a) hydrogen bond formation between the carboxylic groups and b) formation of hydrogen bonds between secondary hydroxyl groups, if spatially permissible. Therefore, the presence of hydroxyl functional groups affects the secondary structure and behavior of stearic acid in the monolayer. - Highlights: • Hydroxyl functional groups affect structure and behavior of acids in the monolayer. • Acids on the surface have a rectangular p2 monolayer structure. • Lattice parameters of acids are uniaxially

  11. Study on the surface hydroxyl group on solid breeding materials by infrared absorption spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Tanaka, Satoru; Taniguchi, Masaki [Tokyo Univ. (Japan). Faculty of Engineering

    1996-10-01

    Hydroxyl groups on the surface of Li{sub 2}O were studied by using a diffuse reflectance method with Fourier transform infrared absorption spectroscopy at high temperature up to 973K under controlled D{sub 2}O or D{sub 2} partial pressure. It was found that hydroxyl groups could exist on Li{sub 2}O surface up to 973K under Ar atmosphere. Under D{sub 2}O containing atmosphere, only the sharp peak at 2520cm{sup -1} was observed at 973K in the O-D stretching vibration region. Below 973K, multiple peaks due to the surface -OD were observed and they showed different behavior with temperature or atmosphere. Multiple peaks mean that surface is not homogeneous for D{sub 2}O adsorption. Assignment of the observed peaks to the surface bonding structure was also discussed. (author)

  12. Effect of Bulky and Hydroxyl Groups on Gas Separation Performance of Polyimide Membranes.

    Science.gov (United States)

    Lee, Bo Mi; Kim, Deuk Ju; Nam, Sang Yong

    2015-03-01

    A series of polyimides were synthesized by a polycondensation reaction using various aromatic dianhydrides and diamines containing bulky cardo and hydroxyl groups. The imidization and chemical structure of the polyimides were confirmed by NMR and FT-IR. The thermal and gas properties of the polyimides were measured by time-lag, XRD, TGA, and DSC studies. The polyimides showed excellent solubility in common organic solvents and high thermal stability. The CO2 selectivity of HPI membrane was higher than traditional polyimides. In particular, the incorporation of hydroxyl groups improved the CO2 permeability of the polyimide due to increased carbon dioxide solubility. The HPI was thermally converted to polybenzoxazole (PBO) at 450 °C.

  13. The Juxtaposition of Ribose Hydroxyl Groups: The Root of Biological Catalysis and the RNA World?

    Science.gov (United States)

    Bernhardt, Harold S.

    2015-06-01

    We normally think of enzymes as being proteins; however, the RNA world hypothesis suggests that the earliest biological catalysts may have been composed of RNA. One of the oldest surviving RNA enzymes we are aware of is the peptidyl transferase centre (PTC) of the large ribosomal RNA, which joins amino acids together to form proteins. Recent evidence indicates that the enzymatic activity of the PTC is principally due to ribose 2 '-OHs. Many other reactions catalyzed by RNA and/or in which RNA is a substrate similarly utilize ribose 2 '-OHs, including phosphoryl transfer reactions that involve the cleavage and/or ligation of the ribose-phosphate backbone. It has recently been proposed by Yakhnin (2013) that phosphoryl transfer reactions were important in the prebiotic chemical evolution of RNA, by enabling macromolecules composed of polyols joined by phosphodiester linkages to undergo recombination reactions, with the reaction energy supplied by the phosphodiester bond itself. The almost unique juxtaposition of the ribose 2'-hydroxyl and 3'-oxygen in ribose-containing polymers such as RNA, which gives ribose the ability to catalyze such reactions, may have been an important factor in the selection of ribose as a component of the first biopolymer. In addition, the juxtaposition of hydroxyl groups in free ribose: (i) allows coordination of borate ions, which could have provided significant and preferential stabilization of ribose in a prebiotic environment; and (ii) enhances the rate of permeation by ribose into a variety of lipid membrane systems, possibly favouring its incorporation into early metabolic pathways and an ancestral ribose-phosphate polymer. Somewhat more speculatively, hydrogen bonds formed by juxtaposed ribose hydroxyl groups may have stabilized an ancestral ribose-phosphate polymer against degradation (Bernhardt and Sandwick 2014). I propose that the almost unique juxtaposition of ribose hydroxyl groups constitutes the root of both biological

  14. Hydroxyl group as IR probe to detect the structure of ionic liquid-acetonitrile mixtures

    Science.gov (United States)

    Xu, Jing; Deng, Geng; Zhou, Yu; Ashraf, Hamad; Yu, Zhi-Wu

    2018-06-01

    Task-specific ionic liquids (ILs) are those with functional groups introduced in the cations or anions of ILs to bring about specific properties for various tasks. In this work, the hydrogen bonding interactions between a hydroxyl functionalized IL 1-(2-hydroxylethyl)-3-methylimidazolium tetrafluoroborate ([C2OHMIM][BF4]) and acetonitrile were investigated in detail by infrared spectroscopy, excess spectroscopy, two-dimensional correlation spectroscopy, combined with hydrogen nuclear magnetic resonance and density functional theory calculations (DFT). The hydroxyl group rather than C2sbnd H is found to be the main interaction site in the cation. And the ν(Osbnd H) is more sensitive than v(C-Hs) to the environment, which has been taken as an intrinsic probe to reflect the structural change of IL. Examining the region of ν(Osbnd H), by combining excess spectroscopy and DFT calculation, a number of species were identified in the mixtures. Other than the hydrogen bond between a cation and an anion, the hydroxyl group allows the formation of a hydrogen bond between two like-charged cations. The Osbnd H⋯O hydrogen bonding interactions in the hydroxyl-mediated cation-cation complexes are cooperative, while Osbnd H⋯F and C2sbnd H⋯F hydrogen bonding interactions in cation-anion complexes are anti-cooperative. These in-depth studies on the properties of the ionic liquid-acetonitrile mixtures may shed light on exploring their applications as mixed solvents and understanding the nature of doubly ionic hydrogen bonds.

  15. Fabrication and characterisation of fluidic based memristor sensor for liquid with hydroxyl group

    Directory of Open Access Journals (Sweden)

    Nor Shahanim Mohamad Hadis

    2017-06-01

    Full Text Available Two types of memristor sensor were fabricated using two different TiO2 deposition methods of sputtering and sol-gel spin coating. The surface morphology of the sensors and the behaviour of the sensors were analysed by using scanning electron microscopy with energy dispersive x-ray system and I-V characterisation system respectively. The sensors were applied with liquid with hydroxyl group to check the capability of this sensor in sensing different concentration of hydroxyl ion inside the liquid. For that purpose, d-glucose liquid with four concentrations of 10mM, 20mM, 30mM and 40mM were chosen. The liquids dispensed onto the TiO2 surface to act as sensing material. The TiO2 surface was initially covered with polydimethylsiloxane to control the liquid. The sensing capability of the sensors was determined via the current-voltage measurement and off-on resistance ratio. The sensitivity of the sensors was analysed from the off-on resistance ratio analysis. Type II memristor sensor which was fabricated using sol-gel spin coating technique recorded high sensitivity of 120.65 (mM−1, while Type I sensor fabricated using the sputtering technique recorded low sensitivity of 0.035 (mM−1. However, SEM-EDX image illustrated that the sputtering technique produced more uniform TiO2 thin film than sol-gel spin coating technique with larger atomic number of oxygen through the sol-gel spin coating technique. This indicates Type II sensor that has large number of oxygen atom produced more reaction with hydroxyl ion inside the liquid. While, Type I sensor produced less reaction compared with Type II and thus produced smaller off-on resistance ratio. Keywords: Fluidic based memristor, Hydroxyl ion, I-V characteristics, Off-on resistance ratio

  16. Chemoselective Methylation of Phenolic Hydroxyl Group Prevents Quinone Methide Formation and Repolymerization During Lignin Depolymerization

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Kwang Ho; Dutta, Tanmoy; Walter, Eric D.; Isern, Nancy G.; Cort, John R.; Simmons, Blake A.; Singh, Seema

    2017-03-30

    Chemoselective blocking of the phenolic hydroxyl (Ar-OH) group by methylation was found to suppress secondary repolymerization and charring during lignin depolymerization. Methylation of Ar-OH prevents formation of reactive quinone methide intermediates, which are partly responsible for undesirable secondary repolymerization reactions. Instead, this structurally modified lignin produces more relatively low molecular weight products from lignin depolymerization compared to unmodified lignin. This result demonstrates that structural modification of lignin is desirable for production of low molecular weight phenolic products. This approach could be directed toward alteration of natural lignification processes to produce biomass more amenable to chemical depolymerization.

  17. Water growth on metals and oxides: binding, dissociation and role of hydroxyl groups

    Energy Technology Data Exchange (ETDEWEB)

    Salmeron, M.; Bluhm, H.; Tatarkhanov, M.; Ketteler, G.; Shimizu, T.K.; Mugarza, A.; Deng, Xingyi; Herranz, T.; Yamamoto, S.; Nilsson, A.

    2008-09-01

    The authors discuss the role of the presence of dangling H bonds from water or from surface hydroxyl species on the wetting behavior of surfaces. Using Scanning Tunneling and Atomic Force Microscopies, and Photoelectron Spectroscopy, they have examined a variety of surfaces, including mica, oxides, and pure metals. They find that in all cases, the availability of free, dangling H-bonds at the surface is crucial for the subsequent growth of wetting water films. In the case of mica electrostatic forces and H-bonding to surface O atoms determine the water orientation in the first layer and also in subsequent layers with a strong influence in its wetting characteristics. In the case of oxides like TiO{sub 2}, Cu{sub 2}O, SiO{sub 2} and Al{sub 2}O{sub 3}, surface hydroxyls form readily on defects upon exposure to water vapor and help nucleate the subsequent growth of molecular water films. On pure metals, such as Pt, Pd, and Ru, the structure of the first water layer and whether or not it exhibits dangling H bonds is again crucial. Dangling H-bonds are provided by molecules with their plane oriented vertically, or by OH groups formed by the partial dissociation of water. By tying the two II atoms of the water molecules into strong H-bonds with pre-adsorbed O on Ru can also quench the wettability of the surface.

  18. Possible mechanism of structural incorporation of Al into diatomite during the deposition process I. Via a condensation reaction of hydroxyl groups.

    Science.gov (United States)

    Liu, Dong; Yu, Wenbin; Deng, Liangliang; Yuan, Weiwei; Ma, Lingya; Yuan, Peng; Du, Peixin; He, Hongping

    2016-01-01

    The structural incorporation of aluminium (Al) into diatomite is investigated by preparing several Al-diatomite composites by loading an Al precursor, hydroxyl aluminum polymer (Al13), onto the surface of diatomite and heating at various temperatures. The results indicate that Al was incorporated and implanted into the structure of diatomite by the condensation reaction of the hydroxyl groups of Al13 and diatomite, and the Si-O-Al(OH) groups were formed during the condensation reaction. Al incorporation by the condensation reaction of hydroxyl groups of Al13 with single silanols of diatomite occurred more readily than that with geminal silanols. The Al incorporation increased solid acidity of diatomite after Al incorporation. The acidity improvement was various for different types of acid sites, depending on the preparation temperature of the Al-incorporated diatomite. Both Brønsted and Lewis acid sites increased greatly after heating at 250 and 350 °C, but only L acid sites significantly improved after heating at 500 °C. These results demonstrate that the structural incorporation of Al(3+) ions into diatomite can occur by the condensation reaction of the hydroxyl groups of the Al precursors and diatomite. Moreover, the rich solid acid sites of Al-incorporated diatomite show its promising application as a solid acid catalyst. Copyright © 2015 Elsevier Inc. All rights reserved.

  19. The assignment of dissociative electron attachment bands in compounds containing hydroxyl and amino groups

    International Nuclear Information System (INIS)

    Skalicky, Tomas; Allan, Michael

    2004-01-01

    Dissociative electron attachment (DEA) spectra were recorded for methanol, phenol, diethylamine, tetramethylhydrazine, piperazine, pyrrole and N,N-dimethylaniline. Comparison with He I photoelectron spectra permitted the assignment of virtually all DEA bands in the saturated compounds to core excited Feshbach resonances with double occupation of Rydberg-like orbitals and various Koopmans' states of the positive ion as a core. These resonances shift to lower energies with alkyl substitution, in contrast to the shape resonances, and are found at surprisingly low energies in the amines. The DEA spectra in the unsaturated compounds show no or only weak evidence for the Rydberg-type Feshbach resonances. It is proposed that DEA in saturated polyatomic molecules containing hydroxyl and amino groups is in general dominated by this type of resonance

  20. Facile synthesis and characterization of novel biodegradable amphiphilic block copolymers bearing pendant hydroxyl groups

    Energy Technology Data Exchange (ETDEWEB)

    Hu, Gaicen; Fan, Xiaoshan; Xu, Bingcan; Zhang, Delong; Hu, Zhiguo, E-mail: zghu@htu.cn

    2014-10-01

    Novel amphiphilic block copolymers bearing pendant hydroxyl groups polylactide-b–poly(3,3-bis(Hydroxymethyl–triazolylmethyl) oxetane)-b–polylactide (PLA-b–PHMTYO-b–PLA) were synthesized via a facile and efficient method. First, the block copolymer intermediates polylactide-b–poly(3,3-Diazidomethyloxetane)-b–polylactide (PLA-b–PBAMO-b–PLA) were synthesized through ring-opening polymerization of lactide using PBAMO as a macroinitiator. Following “Click” reaction of PLA-b–PBAMO-b–PLA with propargyl alcohol provided the targeted amphiphilic block copolymers PLA-b–PHMTYO-b–PLA with pendant hydroxyl groups. The composition and structure of prepared copolymers were characterized by {sup 1}H nuclear magnetic resonance ({sup 1}H NMR) spectroscopy, Fourier transform infrared (FT-IR) and gel permeation chromatography (GPC). The self-assembly behavior of the copolymers in water was investigated by transmission electron microscope (TEM), dynamic light scattering (DLS) and static light scattering (SLS). The results showed that the novel copolymers PLA-b–PHMTYO-b–PLA self-assembled into spherical micelles with diameters ranging from 100 nm to 200 nm in aqueous solution. These copolymers also exhibited low critical micellar concentrations (CMC: 6.9 × 10{sup −4} mg/mL and 3.9 × 10{sup −5} mg/mL, respectively). In addition, the in vitro cytotoxicity of these copolymers was determined in the presence of L929 cells. The results showed that the block copolymers PLA-b–PHMTYO-b–PLA exhibited better biocompatibility. Therefore, these well-defined copolymers are expected to find some applications in drug delivery or tissue engineering. - Highlights: • The method to synthesize PLA-b–PHMTYO-b–PLA is relatively facile and efficient. • PLA-b–PHMTYO-b–PLA self-assembles into spherical micelles with low CMC in water. • PLA-b–PHMTYO-b–PLA exhibits better biocompatibility and biodegradability.

  1. Facile synthesis and characterization of novel biodegradable amphiphilic block copolymers bearing pendant hydroxyl groups

    International Nuclear Information System (INIS)

    Hu, Gaicen; Fan, Xiaoshan; Xu, Bingcan; Zhang, Delong; Hu, Zhiguo

    2014-01-01

    Novel amphiphilic block copolymers bearing pendant hydroxyl groups polylactide-b–poly(3,3-bis(Hydroxymethyl–triazolylmethyl) oxetane)-b–polylactide (PLA-b–PHMTYO-b–PLA) were synthesized via a facile and efficient method. First, the block copolymer intermediates polylactide-b–poly(3,3-Diazidomethyloxetane)-b–polylactide (PLA-b–PBAMO-b–PLA) were synthesized through ring-opening polymerization of lactide using PBAMO as a macroinitiator. Following “Click” reaction of PLA-b–PBAMO-b–PLA with propargyl alcohol provided the targeted amphiphilic block copolymers PLA-b–PHMTYO-b–PLA with pendant hydroxyl groups. The composition and structure of prepared copolymers were characterized by 1 H nuclear magnetic resonance ( 1 H NMR) spectroscopy, Fourier transform infrared (FT-IR) and gel permeation chromatography (GPC). The self-assembly behavior of the copolymers in water was investigated by transmission electron microscope (TEM), dynamic light scattering (DLS) and static light scattering (SLS). The results showed that the novel copolymers PLA-b–PHMTYO-b–PLA self-assembled into spherical micelles with diameters ranging from 100 nm to 200 nm in aqueous solution. These copolymers also exhibited low critical micellar concentrations (CMC: 6.9 × 10 −4 mg/mL and 3.9 × 10 −5 mg/mL, respectively). In addition, the in vitro cytotoxicity of these copolymers was determined in the presence of L929 cells. The results showed that the block copolymers PLA-b–PHMTYO-b–PLA exhibited better biocompatibility. Therefore, these well-defined copolymers are expected to find some applications in drug delivery or tissue engineering. - Highlights: • The method to synthesize PLA-b–PHMTYO-b–PLA is relatively facile and efficient. • PLA-b–PHMTYO-b–PLA self-assembles into spherical micelles with low CMC in water. • PLA-b–PHMTYO-b–PLA exhibits better biocompatibility and biodegradability

  2. Water Contact Angle Dependence with Hydroxyl Functional Groups on Silica Surfaces under CO2 Sequestration Conditions.

    Science.gov (United States)

    Chen, Cong; Zhang, Ning; Li, Weizhong; Song, Yongchen

    2015-12-15

    Functional groups on silica surfaces under CO2 sequestration conditions are complex due to reactions among supercritical CO2, brine and silica. Molecular dynamics simulations have been performed to investigate the effects of hydroxyl functional groups on wettability. It has been found that wettability shows a strong dependence on functional groups on silica surfaces: silanol number density, space distribution, and deprotonation/protonation degree. For neutral silica surfaces with crystalline structure (Q(3), Q(3)/Q(4), Q(4)), as silanol number density decreases, contact angle increases from 33.5° to 146.7° at 10.5 MPa and 318 K. When Q(3) surface changes to an amorphous structure, water contact angle increases 20°. Water contact angle decreases about 12° when 9% of silanol groups on Q(3) surface are deprotonated. When the deprotonation degree increases to 50%, water contact angle decreases to 0. The dependence of wettability on silica surface functional groups was used to analyze contact angle measurement ambiguity in literature. The composition of silica surfaces is complicated under CO2 sequestration conditions, the results found in this study may help to better understand wettability of CO2/brine/silica system.

  3. Effect of surface hydroxyl groups on heat capacity of mesoporous silica

    Science.gov (United States)

    Marszewski, Michal; Butts, Danielle; Lan, Esther; Yan, Yan; King, Sophia C.; McNeil, Patricia E.; Galy, Tiphaine; Dunn, Bruce; Tolbert, Sarah H.; Hu, Yongjie; Pilon, Laurent

    2018-05-01

    This paper quantifies the effect of surface hydroxyl groups on the effective specific and volumetric heat capacities of mesoporous silica. To achieve a wide range of structural diversity, mesoporous silica samples were synthesized by various methods, including (i) polymer-templated nanoparticle-based powders, (ii) polymer-templated sol-gel powders, and (iii) ambigel silica samples dried by solvent exchange at room temperature. Their effective specific heat capacity, specific surface area, and porosity were measured using differential scanning calorimetry and low-temperature nitrogen adsorption-desorption measurements. The experimentally measured specific heat capacity was larger than the conventional weight-fraction-weighted specific heat capacity of the air and silica constituents. The difference was attributed to the presence of OH groups in the large internal surface area. A thermodynamic model was developed based on surface energy considerations to account for the effect of surface OH groups on the specific and volumetric heat capacity. The model predictions fell within the experimental uncertainty.

  4. Enumeration of sugars and sugar alcohols hydroxyl groups by aqueous-based acetylation and MALDI-TOF mass spectrometry

    Science.gov (United States)

    A method is described for enumerating hydroxyl groups on analytes in aqueous media is described, and applied to some common polyalcohols (erythritol, mannitol, and xylitol) and selected carbohydrates. The analytes were derivatized in water with vinyl acetate in presence of sodium phosphate buffer. ...

  5. Hydrogen exchange rate of tyrosine hydroxyl groups in proteins as studied by the deuterium isotope effect on C(zeta) chemical shifts.

    Science.gov (United States)

    Takeda, Mitsuhiro; Jee, Jungoo; Ono, Akira Mei; Terauchi, Tsutomu; Kainosho, Masatsune

    2009-12-30

    We describe a new NMR method for monitoring the individual hydrogen exchange rates of the hydroxyl groups of tyrosine (Tyr) residues in proteins. The method utilizes (2S,3R)-[beta(2),epsilon(1,2)-(2)H(3);0,alpha,beta,zeta-(13)C(4);(15)N]-Tyr, zeta-SAIL Tyr, to detect and assign the (13)C(zeta) signals of Tyr rings efficiently, either by indirect (1)H-detection through 7-8 Hz (1)H(delta)-(13)C(zeta) spin couplings or by direct (13)C(zeta) observation. A comparison of the (13)C(zeta) chemical shifts of three Tyr residues of an 18.2 kDa protein, EPPIb, dissolved in H(2)O and D(2)O, revealed that all three (13)C(zeta) signals in D(2)O appeared at approximately 0.13 ppm ( approximately 20 Hz at 150.9 MHz) higher than those in H(2)O. In a H(2)O/D(2)O (1:1) mixture, however, one of the three signals for (13)C(zeta) appeared as a single peak at the averaged chemical shifts, and the other two appeared as double peaks at exactly the same chemical shifts in H(2)O and D(2)O, in 50 mM phosphate buffer (pH 6.6) at 40 degrees C. These three peaks were assigned to Tyr-36, Tyr-120, and Tyr-30, from the lower to higher chemical shifts, respectively. The results indicate that the hydroxyl proton of Tyr-120 exchanges faster than a few milliseconds, whereas those of Tyr-30 and Tyr-36 exchange more slowly. The exchange rate of the Tyr-30 hydroxyl proton, k(ex), under these conditions was determined by (13)C NMR exchange spectroscopy (EXSY) to be 9.2 +/- 1.1 s(-1). The Tyr-36 hydroxyl proton, however, exchanges too slowly to be determined by EXSY. These profound differences among the hydroxyl proton exchange rates are closely related to their relative solvent accessibility and the hydrogen bonds associated with the Tyr hydroxyl groups in proteins.

  6. Sucrose derivatives and the selective benzoylation of the secondary hydroxyl groups of 6,1',6'-tri-O-tritylsucrose

    International Nuclear Information System (INIS)

    Holzapfel, C.W.; Koekemoer, J.M.; Marais, C.F.

    1984-01-01

    The preparation and 500 MHz 1 H-n.m.r. spectra of a number of sucrose derivatives are described. The assignment of the individual proton resonances in these compounds contributed to the identification of the mono- and dibenzoates obtained by benzoylation of 6,1',6'-tri-O-tritylsucrose following regioselective activation of the secondary hydroxyl groups by reaction with dibutyltin oxide or bis(tributyltin) oxide

  7. Cisplatin enhances the formation of DNA single- and double-strand breaks by hydrated electrons and hydroxyl radicals.

    Science.gov (United States)

    Rezaee, Mohammad; Sanche, Léon; Hunting, Darel J

    2013-03-01

    The synergistic interaction of cisplatin with ionizing radiation is the clinical rationale for the treatment of several cancers including head and neck, cervical and lung cancer. The underlying molecular mechanism of the synergy has not yet been identified, although both DNA damage and repair processes are likely involved. Here, we investigate the indirect effect of γ rays on strand break formation in a supercoiled plasmid DNA (pGEM-3Zf-) covalently modified by cisplatin. The yields of single- and double-strand breaks were determined by irradiation of DNA and cisplatin/DNA samples with (60)Co γ rays under four different scavenging conditions to examine the involvement of hydrated electrons and hydroxyl radicals in inducing the DNA damage. At 5 mM tris in an N2 atmosphere, the presence of an average of two cisplatins per plasmid increased the yields of single- and double-strand breaks by factors of 1.9 and 2.2, respectively, relative to the irradiated unmodified DNA samples. Given that each plasmid of 3,200 base pairs contained an average of two cisplatins, this represents an increase in radiosensitivity of 3,200-fold on a per base pair basis. When hydrated electrons were scavenged by saturating the samples with N2O, these enhancement factors decreased to 1.5 and 1.2, respectively, for single- and double-strand breaks. When hydroxyl radicals were scavenged using 200 mM tris, the respective enhancement factors were 1.2 and 1.6 for single- and double-strand breaks, respectively. Furthermore, no enhancement in DNA damage by cisplatin was observed after scavenging both hydroxyl radicals and hydrated electrons. These findings show that hydrated electrons can induce both single- and double-strand breaks in the platinated DNA, but not in unmodified DNA. In addition, cisplatin modification is clearly an extremely efficient means of increasing the formation of both single- and double-strand breaks by the hydrated electrons and hydroxyl radicals created by ionizing

  8. Application of density functional theory to the nitric oxide heterogeneous reduction mechanism in the presence of hydroxyl and carbonyl groups

    International Nuclear Information System (INIS)

    Zhang, Hai; Jiang, Xiumin; Liu, Jiaxun; Shen, Jun

    2014-01-01

    Highlights: • The role of hydroxyl and carbonyl groups are studied on two modified zigzag models. • Energetics and kinetics for the proposed pathways are chiefly investigated. • New active sites are beneficial for NO adsorption and N-O bond dissociation. • The highly exothermicity of C(NCO) formation is helpful for CO 2 and N 2 elimination. - Abstract: Comprehensive theoretical calculations are carried out to investigate the nitric oxide (NO) heterogeneous reduction mechanism in the presence of hydroxyl (-OH) and carbonyl (>C=O) groups. Energetics (activation energy and thermochemistry data) and kinetics (thermal rate constant) for the proposed pathways are provided by density functional theory (DFT) and conventional transition state theory (TST), respectively. The role played by -OH and >C=O has been clarified. In the presence of -OH, four stepwise reactions with the highest energy barrier of 251.7 kJ/mol are found to produce new active sites. Subsequently, a number of elementary reactions with energy barrier below 116.1 kJ/mol take place to reduce NO. The role of > C=O is to yield NCO intermediate. The formation of NCO is highly exothermic with 709.4 kJ/mol, which contributes to the elimination of carbon dioxide (CO 2 ) and nitrogen (N 2 ). The discovered mechanism is consistent with previous experimental observation that NO heterogeneous reduction is enhanced due to the presence of oxygen

  9. Enhanced electrical properties in solution-processed InGaZnO thin-film transistors by viable hydroxyl group transfer process

    Science.gov (United States)

    Kim, Do-Kyung; Jeong, Hyeon-Seok; Kwon, Hyeok Bin; Kim, Young-Rae; Kang, Shin-Won; Bae, Jin-Hyuk

    2018-05-01

    We propose a simple hydroxyl group transfer method to improve the electrical characteristics of solution-processed amorphous InGaZnO (IGZO) thin-film transistors (TFTs). Tuned poly(dimethylsiloxane) elastomer, which has a hydroxyl group as a terminal chemical group, was adhered temporarily to an IGZO thin-film during the solidification step to transfer and supply sufficient hydroxyl groups to the IGZO thin-film. The transferred hydroxyl groups led to efficient hydrolysis and condensation reactions, resulting in a denser metal–oxygen–metal network being achieved in the IGZO thin-film compared to the conventional IGZO thin-film. In addition, it was confirmed that there was no morphological deformation, including to the film thickness and surface roughness. The hydroxyl group transferred IGZO based TFTs exhibited enhanced electrical properties (field-effect mobility of 2.21 cm2 V‑1 s‑1, and on/off current ratio of 106) compared to conventional IGZO TFTs (field-effect mobility of 0.73 cm2 V‑1 s‑1 and on/off current ratio of 105).

  10. Limonene dehydrogenase hydroxylates the allylic methyl group of cyclic monoterpenes in the anaerobic terpene degradation by Castellaniella defragrans.

    Science.gov (United States)

    Puentes-Cala, Edinson; Liebeke, Manuel; Markert, Stephanie; Harder, Jens

    2018-05-01

    The enzymatic functionalization of hydrocarbons is a central step in the global carbon cycle initiating the mineralization of methane, isoprene and monoterpenes, the most abundant biologically produced hydrocarbons. Also, terpene-modifying enzymes have found many applications in the energy-economic biotechnological production of fine chemicals. Here we describe a limonene dehydrogenase that was purified from the facultatively anaerobic betaproteobacterium Castellaniella defragrans 65Phen grown on monoterpenes under denitrifying conditions in the absence of molecular oxygen. The purified limonene:ferrocenium oxidoreductase activity hydroxylated the methyl group of limonene (1-methyl-4-(1-methylethenyl)-cyclohex-1-ene) yielding perillyl alcohol ([4-(prop-1-en-2-yl)cyclohex-1-en-1-yl]methanol). The enzyme had a dithiothreitol:perillyl alcohol oxidoreductase activity yielding limonene. Mass spectrometry and molecular size determinations revealed a heterodimeric enzyme comprising CtmA and CtmB. Recently the two proteins had been identified by transposon mutagenesis and proteomics as part of the cyclic terpene metabolism ( ctm ) in Castellaniella defragrans and were annotated as FAD-dependent oxidoreductases of the protein domain family phytoene dehydrogenases and related proteins (COG1233). CtmAB is the first heterodimeric enzyme in this protein superfamily. Flavins in the purified CtmAB are oxidized by ferrocenium and are reduced by limonene. Heterologous expression of CtmA, CtmB and CtmAB in E. coli demonstrated that limonene dehydrogenase activity required both subunits carrying each a flavin cofactor. Native CtmAB oxidized a wide range of monocyclic monoterpenes containing the allylic methyl group motif (1-methyl-cyclohex-1-ene). In conclusion, we have identified CtmAB as a hydroxylating limonene dehydrogenase and the first heteromer in a family of FAD-dependent dehydrogenases acting on allylic methylene or methyl CH-bonds. We suggest a placement in EC 1

  11. Influence of hydroxyl group position and temperature on thermophysical properties of tetraalkylammonium hydroxide ionic liquids with alcohols.

    Directory of Open Access Journals (Sweden)

    Pankaj Attri

    Full Text Available In this work, we have explored the thermophysical properties of tetraalkylammonium hydroxide ionic liquids (ILs such as tetrapropylammonium hydroxide (TPAH and tetrabutylammonium hydroxide (TBAH with isomers of butanol (1-butanol, 2-butanol and 2-methyl-2-propanol within the temperature range 293.15-313.15 K, with interval of 5 K and over the varied concentration range of ILs. The molecular interactions between ILs and butanol isomers are essential for understanding the function of ILs in related measures and excess functions are sensitive probe for the molecular interactions. Therefore, we calculated the excess molar volume (V(E and the deviation in isentropic compressibility (Δκs using the experimental values such as densities (ρ and ultrasonic sound velocities (u that are measured over the whole compositions range at five different temperatures (293.15, 298.15, 303.15, 308.15 and 313.15 K and atmospheric pressure. These excess functions were adequately correlated by using the Redlich-Kister polynomial equation. It was observed that for all studied systems, the V(E and Δκs values are negative for the whole composition range at 293.15 K. And, the excess function follows the sequence: 2-butanol>1-butanol>2-methyl-2-propanol, which reveals that (primary or secondary or tertiary position of hydroxyl group influence the magnitude of interactions with ILs. The negative values of excess functions are contributions from the ion-dipole interaction, hydrogen bonding and packing efficiency between the ILs and butanol isomers. Hence, the position of hydroxyl group plays an important role in the interactions with ILs. The hydrogen bonding features between ILs and alcohols were analysed using molecular modelling program by using HyperChem 7.

  12. Influence of hydroxyl group position and temperature on thermophysical properties of tetraalkylammonium hydroxide ionic liquids with alcohols.

    Science.gov (United States)

    Attri, Pankaj; Baik, Ku Youn; Venkatesu, Pannuru; Kim, In Tae; Choi, Eun Ha

    2014-01-01

    In this work, we have explored the thermophysical properties of tetraalkylammonium hydroxide ionic liquids (ILs) such as tetrapropylammonium hydroxide (TPAH) and tetrabutylammonium hydroxide (TBAH) with isomers of butanol (1-butanol, 2-butanol and 2-methyl-2-propanol) within the temperature range 293.15-313.15 K, with interval of 5 K and over the varied concentration range of ILs. The molecular interactions between ILs and butanol isomers are essential for understanding the function of ILs in related measures and excess functions are sensitive probe for the molecular interactions. Therefore, we calculated the excess molar volume (V(E) ) and the deviation in isentropic compressibility (Δκs ) using the experimental values such as densities (ρ) and ultrasonic sound velocities (u) that are measured over the whole compositions range at five different temperatures (293.15, 298.15, 303.15, 308.15 and 313.15 K) and atmospheric pressure. These excess functions were adequately correlated by using the Redlich-Kister polynomial equation. It was observed that for all studied systems, the V(E) and Δκs values are negative for the whole composition range at 293.15 K. And, the excess function follows the sequence: 2-butanol>1-butanol>2-methyl-2-propanol, which reveals that (primary or secondary or tertiary) position of hydroxyl group influence the magnitude of interactions with ILs. The negative values of excess functions are contributions from the ion-dipole interaction, hydrogen bonding and packing efficiency between the ILs and butanol isomers. Hence, the position of hydroxyl group plays an important role in the interactions with ILs. The hydrogen bonding features between ILs and alcohols were analysed using molecular modelling program by using HyperChem 7.

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

    Science.gov (United States)

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

    1995-01-01

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

  14. Formation of hydroxyl groups and exchange with deuterium on NaHX and NaHY zeolites

    International Nuclear Information System (INIS)

    Kubelkova, L.; Novakova, J.

    1976-01-01

    Deammoniation and dehydroxylation of Na(NH 4 )X and Na(NH 4 )Y zeolites were compared. With the X type, both processes overlapped and proceeded more easily than with the Y type. Both H forms contained structural OH groups and hydroxyls denoted as SiOH, to which the 3740 cm -1 band in the IR spectrum was assigned. In addition, the NaHX zeolite contained OH groups characterized by the 3700 and 3600 cm -1 bands. Certain differences in the behaviour of NaHX and NaHY zeolites during deammoniation and dehydroxylation might be attributed to the presence of ''non-localizable'' H atoms. The active sites for the D 2 -OH exchange were probably formed during dehydroxylation. Hydrogen in SiOH groups was replaced by deuterium in both zeolite types more slowly than H atoms in other OH groups, which influenced the kinetic variations in the gaseous phase. The presence of water in the gaseous phase affected the kinetics and could distort the determination of the number of H atoms bound in the zeolites. (author)

  15. Hydroxyl group induced adsorption of four-nitro benzoic acid on Si(100) 2x1 surface

    International Nuclear Information System (INIS)

    Ihm, K.; Kang, T.-H.; Hwang, C.C.; Kim, K.-J.; Hwang, H.-N.; Kim, H.-D.; Han, J.H.; Moon, S.; Kim, B.; POSTECH

    2004-01-01

    Full text: A number of studies have been conducted on self-assembled monolayers (SAMs) in order to study the adhesion of polymer films on various substrates. Recently, the studies on SAMs on the semiconductor substrate are more motivated because of their possible application to nanoscale devices. For the electronic and chemical properties suitable for various applications, the aromatic ring has been used as a building block of various molecules forming SAMs. Here, we used four-nitro benzoic acid (4-NBA) as a model planar aromatic compound, in which the phenyl ring, the carboxylic functional group, and NO2 are on the same plane. The adsorption mechanism of 4-NBA on the in-situ prepared OH/Si(100) 2x1 surface was investigated using x-ray photoelectron spectroscopy and near-edge x-ray absorption e structure. The results revealed that the 4-NBA molecule reacts with the hydroxyl group on the Si(100) 2x1 surface through deprotonation of the carboxyl group. The saturation coverage of 4-NBA estimated by the O 1s ratio is 1/2 ML. Additionally, we could observe the desorption of the oxygen atom from the NO2 moiety of the 4-NBA upon irradiating the surface by photons of 500 eV

  16. Photophysical properties and localization of chlorins substituted with methoxy groups, hydroxyl groups and alkyl chains in liposome-like cellular membrane

    Energy Technology Data Exchange (ETDEWEB)

    Al-Omari, S [Department of Physics, Hashemite University, Zarqa 13115 (Jordan)

    2007-06-01

    Some of the photophysical properties (stationary absorbance and fluorescence, fluorescence decay times and singlet oxygen quantum yields) of chlorins substituted with methoxy groups, hydroxyl groups and hydrocarbonic chains were studied in ethanol and dipalmitoyl-phosphatidylcholine (DPPC) liposomes using steady-state and time-resolved fluorescence spectroscopies. The photophysical behaviors of the chlorins in liposomes like cellular membrane were compared with those obtained from chlorin-liposome systems delivered to Jurkat cells in order to select potent photosensitizers for the photodynamic treatment of cancer. The localization of the studied chlorins inside liposomes was found to depend strongly on the substituents of chlorins. Absorption spectra of chlorins embedded in DPPC-liposomes have been recorded in the temperature range of 20-70 deg. C. It is demonstrated that the location of the chlorin molecules depends on the phase state of the phospholipids. These observations are confirmed by the fluorescence lifetimes, singlet oxygen lifetimes and singlet oxygen quantum yields results.

  17. Interactions of lead with carboxyl and hydroxyl-decorated(10, 0) single-walled carbon nanotubes: First-principle calculations

    International Nuclear Information System (INIS)

    Bastos, M.; Camps, I.

    2013-01-01

    Absorption of Pb on a zigzag (10, 0) carbon nanotube (CNT) surface, pure and functionalized with carboxyl (-COOH) and hydroxyl (-OH) groups was investigated using the density functional theory. Binding energy calculations were performed and indicated that adsorption of the Pb metal on the surface of the three nanotubes were stable, through a chemisorption. Therefore, CNTs are a feasible active material for filters that retain such metal. After Pb adsorption, the CNT and COOH-CNT conductivity changed, from semiconductor to half-metallic for CNT and from semiconductor to metallic for COOH-CNT, which can serve as a signal for Pb sensor. In all three cases adsorption produced a change in nanotube magnetism, which can also serve as a sensitive signal for chemical sensors. After adsorption of Pb, the changes in binding energy, charge transfer, conductance and magnetism may lead to the different response in the CNTs-based sensors. Thus, it is expected that these results could provide helpful information for the design and fabrication of the Pb sensing devices.

  18. Self-rolling of an aluminosilicate sheet into a single walled imogolite nanotube: The role of the hydroxyl arrangement

    Energy Technology Data Exchange (ETDEWEB)

    González, R. I.; Rogan, J.; Valdivia, J. A.; Munoz, F.; Valencia, F.; Ramírez, M.; Kiwi, M. [Departamento de Física, Facultad de Ciencias, Universidad de Chile, Casilla 653, Santiago, 7800024 (Chile); Centro para el Desarrollo de la Nanociencia y la Nanotecnología, CEDENNA, Avda. Ecuador 3493, Santiago, 9170124 (Chile); Ramírez, R. [Facultad de Física, Universidad Católica de Chile, Casilla 306, Santiago, 7820436 (Chile); Centro para el Desarrollo de la Nanociencia y la Nanotecnología, CEDENNA, Avda. Ecuador 3493, Santiago, 9170124 (Chile)

    2015-12-31

    Imogolite is an inorganic nanotube, that forms naturally in weathered volcanic ashes, and it can be synthesized in nearly monodisperse diameters. However, long after its successful synthesis, the details of the way it is achieved are not fully understood. Here we elaborate on a model of its synthesis, which starts with a planar aluminosilicate sheet that is allowed to evolve freely, by means of classical molecular dynamics, until it achieves its minimum energy configuration. The minimal structures that the system thus adopts are tubular, scrolled, and more complex conformations, depending mainly on temperature as a driving force. Here we focus on the effect that the arrangement of the hydroxyl groups in the inner wall of the nanotube have on the minimal nanotubular configurations that we obtain are monodispersed in diameter, and quite similar to both from the those of weathered natural volcanic ashes, and to the ones that are synthesized in the laboratory. In this contribution we expand on the atomic mechanisms behind those behaviors.

  19. Self-rolling of an aluminosilicate sheet into a single walled imogolite nanotube: The role of the hydroxyl arrangement

    International Nuclear Information System (INIS)

    González, R. I.; Rogan, J.; Valdivia, J. A.; Munoz, F.; Valencia, F.; Ramírez, M.; Kiwi, M.; Ramírez, R.

    2015-01-01

    Imogolite is an inorganic nanotube, that forms naturally in weathered volcanic ashes, and it can be synthesized in nearly monodisperse diameters. However, long after its successful synthesis, the details of the way it is achieved are not fully understood. Here we elaborate on a model of its synthesis, which starts with a planar aluminosilicate sheet that is allowed to evolve freely, by means of classical molecular dynamics, until it achieves its minimum energy configuration. The minimal structures that the system thus adopts are tubular, scrolled, and more complex conformations, depending mainly on temperature as a driving force. Here we focus on the effect that the arrangement of the hydroxyl groups in the inner wall of the nanotube have on the minimal nanotubular configurations that we obtain are monodispersed in diameter, and quite similar to both from the those of weathered natural volcanic ashes, and to the ones that are synthesized in the laboratory. In this contribution we expand on the atomic mechanisms behind those behaviors

  20. Lung damage in mice after inhalation of nanofilm spray products: the role of perfluorination and free hydroxyl groups

    DEFF Research Database (Denmark)

    Nørgaard, Asger W; Larsen, Søren T.; Hammer, Maria

    2010-01-01

    concentrations (18.4 mg/m(3)) was observed. The alkylsilane-based product (NFP 2) had no effect at the concentrations studied. Experiments with different types of perfluorinated silanes and alkylsiloxanes showed that the toxic effects did not arise solely from the perfluorination. The number of free hydroxyl...

  1. Synthesis of MOF having hydroxyl functional side groups and optimization of activation process for the maximization of its BET surface area

    International Nuclear Information System (INIS)

    Kim, Jongsik; Kim, Dong Ok; Kim, Dong Wook; Sagong, Kil

    2013-01-01

    To accomplish the postsynthetic modification of MOF with organic-metal precursors (OMPs) described in our previous researches more efficiently, synthesis of MOF (HCC-2) possessing relatively larger pore size as well as higher number of hydroxyl functional side groups per its base unit than those of HCC-1 has been successfully conducted via adopting 1,4-di-(4-carboxy-2,6-dihydroxyphenyl)benzene as an organic ligand and Zn(NO 3 ) 2 ·6H 2 O as a metal source, respectively. Also, optimization about the Activation process of HCC-2 was performed to maximize its BET (Brunauer–Emmett–Teller) surface area which was proved to be proportional to the number of exposed active sites on which its postsynthetic modification occurred. However, Activation process having been validated to be so effective with the acquirement of highly-purified HCC-1 (CO 2 supercritical drying step followed by vacuum drying step) was less satisfactory with the case of HCC-2. This might be attributed to relatively higher hydrophilicity and bulkier molecular structure of organic ligand of HCC-2. However, it was readily settled by simple modification of above Activation process. Moreover, indispensable residues composed of both DMF and its thermally degraded derivatives which were chemically attached via coordination bond with hydroxyl functionalities even after Activation process III might enable their H 2 adsorption properties to be seriously debased compared to that of IRMOF-16 having no hydroxyl functionalities. - Graphical abstract: Synthesis of new-structured MOF (HCC-2) simultaneously possessing relatively larger pore size as well as higher number of hydroxyl functional side groups per its base unit at the same time than those of HCC-1 has been performed via adopting 1,4-di-(4-carboxy-2,6-dihydroxyphenyl)benzene as an organic ligand and Zn(NO 3 ) 2 ·6H 2 O as a metal source, respectively. Also, the optimization of activation process for HCC-2 was conducted to maximize its BET surface area

  2. A Renormalisation Group Method. V. A Single Renormalisation Group Step

    Science.gov (United States)

    Brydges, David C.; Slade, Gordon

    2015-05-01

    This paper is the fifth in a series devoted to the development of a rigorous renormalisation group method applicable to lattice field theories containing boson and/or fermion fields, and comprises the core of the method. In the renormalisation group method, increasingly large scales are studied in a progressive manner, with an interaction parametrised by a field polynomial which evolves with the scale under the renormalisation group map. In our context, the progressive analysis is performed via a finite-range covariance decomposition. Perturbative calculations are used to track the flow of the coupling constants of the evolving polynomial, but on their own perturbative calculations are insufficient to control error terms and to obtain mathematically rigorous results. In this paper, we define an additional non-perturbative coordinate, which together with the flow of coupling constants defines the complete evolution of the renormalisation group map. We specify conditions under which the non-perturbative coordinate is contractive under a single renormalisation group step. Our framework is essentially combinatorial, but its implementation relies on analytic results developed earlier in the series of papers. The results of this paper are applied elsewhere to analyse the critical behaviour of the 4-dimensional continuous-time weakly self-avoiding walk and of the 4-dimensional -component model. In particular, the existence of a logarithmic correction to mean-field scaling for the susceptibility can be proved for both models, together with other facts about critical exponents and critical behaviour.

  3. The Hydroxyl at Position C1 of Genipin Is the Active Inhibitory Group that Affects Mitochondrial Uncoupling Protein 2 in Panc-1 Cells.

    Directory of Open Access Journals (Sweden)

    Yang Yang

    Full Text Available Genipin (GNP effectively inhibits uncoupling protein 2 (UCP2, which regulates the leakage of protons across the inner mitochondrial membrane. UCP2 inhibition may induce pancreatic adenocarcinoma cell death by increasing reactive oxygen species (ROS levels. In this study, the hydroxyls at positions C10 (10-OH and C1 (1-OH of GNP were hypothesized to be the active groups that cause these inhibitory effects. Four GNP derivatives in which the hydroxyl at position C10 or C1 was replaced with other chemical groups were synthesized and isolated. Differences in the inhibitory effects of GNP and its four derivatives on pancreatic carcinoma cell (Panc-1 proliferation were assessed. The effects of GNP and its derivatives on apoptosis, UCP2 inhibition and ROS production were also studied to explore the relationship between GNP's activity and its structure. The derivatives with 1-OH substitutions, geniposide (1-GNP1 and 1-ethyl-genipin (1-GNP2 lacked cytotoxic effects, while the other derivatives that retained 1-OH, 10-piv-genipin (10-GNP1 and 10-acetic acid-genipin (10-GNP2 exerted biological effects similar to those of GNP, even in the absence of 10-OH. Thus, 1-OH is the key functional group in the structure of GNP that is responsible for GNP's apoptotic effects. These cytotoxic effects involve the induction of Panc-1 cell apoptosis through UCP2 inhibition and subsequent ROS production.

  4. The Hydroxyl at Position C1 of Genipin Is the Active Inhibitory Group that Affects Mitochondrial Uncoupling Protein 2 in Panc-1 Cells.

    Science.gov (United States)

    Yang, Yang; Yang, Yifu; Hou, Jianwei; Ding, Yue; Zhang, Tong; Zhang, Yong; Wang, Jianying; Shi, Chenchen; Fu, Wenwei; Cai, Zhenzhen

    2016-01-01

    Genipin (GNP) effectively inhibits uncoupling protein 2 (UCP2), which regulates the leakage of protons across the inner mitochondrial membrane. UCP2 inhibition may induce pancreatic adenocarcinoma cell death by increasing reactive oxygen species (ROS) levels. In this study, the hydroxyls at positions C10 (10-OH) and C1 (1-OH) of GNP were hypothesized to be the active groups that cause these inhibitory effects. Four GNP derivatives in which the hydroxyl at position C10 or C1 was replaced with other chemical groups were synthesized and isolated. Differences in the inhibitory effects of GNP and its four derivatives on pancreatic carcinoma cell (Panc-1) proliferation were assessed. The effects of GNP and its derivatives on apoptosis, UCP2 inhibition and ROS production were also studied to explore the relationship between GNP's activity and its structure. The derivatives with 1-OH substitutions, geniposide (1-GNP1) and 1-ethyl-genipin (1-GNP2) lacked cytotoxic effects, while the other derivatives that retained 1-OH, 10-piv-genipin (10-GNP1) and 10-acetic acid-genipin (10-GNP2) exerted biological effects similar to those of GNP, even in the absence of 10-OH. Thus, 1-OH is the key functional group in the structure of GNP that is responsible for GNP's apoptotic effects. These cytotoxic effects involve the induction of Panc-1 cell apoptosis through UCP2 inhibition and subsequent ROS production.

  5. Structure–Activity Relationship of Oligomeric Flavan-3-ols: Importance of the Upper-Unit B-ring Hydroxyl Groups in the Dimeric Structure for Strong Activities

    Directory of Open Access Journals (Sweden)

    Yoshitomo Hamada

    2015-10-01

    Full Text Available Proanthocyanidins, which are composed of oligomeric flavan-3-ol units, are contained in various foodstuffs (e.g., fruits, vegetables, and drinks and are strongly biologically active compounds. We investigated which element of the proanthocyanidin structure is primarily responsible for this functionality. In this study, we elucidate the importance of the upper-unit of 4–8 condensed dimeric flavan-3-ols for antimicrobial activity against Saccharomyces cerevisiae (S. cerevisiae and cervical epithelioid carcinoma cell line HeLa S3 proliferation inhibitory activity. To clarify the important constituent unit of proanthocyanidin, we synthesized four dimeric compounds, (−-epigallocatechin-[4,8]-(+-catechin, (−-epigallocatechin-[4,8]-(−-epigallocatechin, (−-epigallocatechin-[4,8]-(−-epigallocatechin-3-O-gallate, and (+-catechin-[4,8]-(−-epigallocatechin and performed structure–activity relationship (SAR studies. In addition to antimicrobial activity against S. cerevisiae and proliferation inhibitory activity on HeLa S3 cells, the correlation of 2,2-diphenyl-l-picrylhydrazyl radical scavenging activity with the number of phenolic hydroxyl groups was low. On the basis of the results of our SAR studies, we concluded that B-ring hydroxyl groups of the upper-unit of the dimer are crucially important for strong and effective activity.

  6. DNA Binding Hydroxyl Radical Probes

    OpenAIRE

    Tang, Vicky J; Konigsfeld, Katie M; Aguilera, Joe A; Milligan, Jamie R

    2012-01-01

    The hydroxyl radical is the primary mediator of DNA damage by the indirect effect of ionizing radiation. It is a powerful oxidizing agent produced by the radiolysis of water and is responsible for a significant fraction of the DNA damage associated with ionizing radiation. There is therefore an interest in the development of sensitive assays for its detection. The hydroxylation of aromatic groups to produce fluorescent products has been used for this purpose. We have examined four different c...

  7. The effect of surfactant-free TiO2 surface hydroxyl groups on physicochemical, optical and self-cleaning properties of developed coatings on polycarbonate

    Science.gov (United States)

    Yaghoubi, H.; Dayerizadeh, A.; Han, S.; Mulaj, M.; Gao, W.; Li, X.; Muschol, M.; Ma, S.; Takshi, A.

    2013-12-01

    TiO2 is a prototypical transition metal oxide with physicochemical properties that can be modified more readily through sol-gel synthesis than through other techniques. Herein, we report on the change in the density of the hydroxyl groups on the surface of synthesized surfactant-free TiO2 nanoparticles in water due to varying the pH (7.3, 8.3, 9.3 and 10.3) of the peroxotitanium complex, i.e. the amorphous sol, prior to refluxing. This resulted in colloidal solutions with differing crystallinity, nanoparticle size, optical indirect bandgaps and photocatalytic activity. It was shown that increasing the density of hydroxyl groups on TiO2 particles coupled with low-temperature annealing (90 °C) induced an anatase to rutile transformation. Increasing the pH of the peroxotitanium complex interrupted the formation of anatase phase in crystalline sol, as evidenced by intensity increases of the Raman bands at ˜822 (Ti-O-H) and 906 cm-1 (vibrational Ti-O-H) and an intensity decrease of the band at 150 cm-1 (anatase photonic Eg). Films prepared from higher pH suspensions showed lower roughness. The reaction rate constants for photo-induced self-cleaning activity of TiO2 films prepared from colloidal solutions at pH 7.3, 8.3, 9.3 and 10.3 were estimated at 0.017 s-1, 0.014 s-1, 0.007 s-1 and 0.006 s-1, respectively.

  8. The effect of surfactant-free TiO2 surface hydroxyl groups on physicochemical, optical and self-cleaning properties of developed coatings on polycarbonate

    International Nuclear Information System (INIS)

    Yaghoubi, H; Dayerizadeh, A; Han, S; Takshi, A; Mulaj, M; Muschol, M; Gao, W; Li, X; Ma, S

    2013-01-01

    TiO 2 is a prototypical transition metal oxide with physicochemical properties that can be modified more readily through sol–gel synthesis than through other techniques. Herein, we report on the change in the density of the hydroxyl groups on the surface of synthesized surfactant-free TiO 2 nanoparticles in water due to varying the pH (7.3, 8.3, 9.3 and 10.3) of the peroxotitanium complex, i.e. the amorphous sol, prior to refluxing. This resulted in colloidal solutions with differing crystallinity, nanoparticle size, optical indirect bandgaps and photocatalytic activity. It was shown that increasing the density of hydroxyl groups on TiO 2 particles coupled with low-temperature annealing (90 °C) induced an anatase to rutile transformation. Increasing the pH of the peroxotitanium complex interrupted the formation of anatase phase in crystalline sol, as evidenced by intensity increases of the Raman bands at ∼822 (Ti–O–H) and 906 cm −1 (vibrational Ti–O–H) and an intensity decrease of the band at 150 cm −1 (anatase photonic E g ). Films prepared from higher pH suspensions showed lower roughness. The reaction rate constants for photo-induced self-cleaning activity of TiO 2 films prepared from colloidal solutions at pH 7.3, 8.3, 9.3 and 10.3 were estimated at 0.017 s −1 , 0.014 s −1 , 0.007 s −1 and 0.006 s −1 , respectively. (paper)

  9. Ammonia IRMS-TPD measurements and DFT calculation on acidic hydroxyl groups in CHA-type zeolites.

    Science.gov (United States)

    Suzuki, Katsuki; Sastre, German; Katada, Naonobu; Niwa, Miki

    2007-12-07

    Brønsted acidity of H-chabazite (CHA) zeolites (Si : Al(2) = 4.2) was investigated by means of ammonia infrared-mass spectrometry/temperature-programmed desorption (IRMS-TPD) methods and density functional calculations. Four IR bands were observed at 3644, 3616, 3575 and 3538 cm(-1), and they were ascribable to the acidic OH groups on four nonequivalent oxygen sites in the CHA structure. The absorption band at 3538 cm(-1) was attributed to the O(4)H in the 6-membered ring (MR), and ammonia adsorption energy (DeltaU) of this OH group was the lowest among the 4 kinds of OH groups. The other 3 bands were assigned to the acidic OH groups in 8MR. It was observed that the DeltaU in 8 and 6MR were 131 (+/-3) and 101 kJ mol(-1), respectively. On the other hand, the density functional theory (DFT) calculations within periodic boundary conditions yielded the adsorption energies on these OH groups in 8 and 6MR to be ca. 130 and 110 kJ mol(-1), respectively, in good agreement with the experimentally-observed values.

  10. The effect of hydroxyl groups on the stability and thermodynamic properties of polyhydroxylated xanthones as calculated by density functional theory

    International Nuclear Information System (INIS)

    Qu, Ruijuan; Liu, Hongxia; Zhang, Qi; Flamm, Alison; Yang, Xi; Wang, Zunyao

    2012-01-01

    Highlights: ► The strength of the hydrogen bonds existed in PHOXTHs is ascertained. ► Good linear relations exist between the thermodynamic properties and N PHOS . ► The relative stability order of PHOXTH congeners is theoretically proposed. ► There is a good relation between C p,m and the temperature. - Abstract: There are three types of intramolecular hydrogen bonds with bond energy about 52 kJ mol −1 , 12 kJ mol −1 , 20 kJ mol −1 , respectively in PHOXTHs which were determined by computation on B3LYP/6-311G** level. The internal rotational potentials of the hydroxy group of 1-MHOXTH and 4′-MHOXTH are evaluated, and the influences of the spatial orientation of the hydroxy groups on the intramolecular hydrogen bonds and molecular stability are illustrated. The standard enthalpy of formation (Δ f H θ ) and standard Gibbs energy of formation (Δ f G θ ) for the most stable conformation of 135 PHOXTHs are calculated by the combination of Gaussian 03 and isodesmic reactions and the theoretical order of relative stability is proposed according to the relative magnitude of calculated Δ f G θ values. In addition, the values of molar heat capacities at constant pressure (C p,m ) from 200 to 1000 K for PHOXTH congeners are calculated.

  11. Effect of substituted hydroxyl groups in the changes of solution turbidity in the oxidation of aromatic contaminants.

    Science.gov (United States)

    Villota, N; Jm, Lomas; Lm, Camarero

    2017-01-01

    This paper deals with the changes of turbidity that are generated in aqueous solutions of phenol when they are oxidized by using different Fenton technologies. Results revealed that if the Fenton reaction was promoted with UV light, the turbidity that was generated in the water doubled. Alternatively, the use of ultrasonic waves produced an increase in turbidity which initially proceeded slowly, reaching intensities eight times higher than in the conventional Fenton treatment. As well, the turbidity showed a high dependence on pH. It is therefore essential to control acidity throughout the reaction. The maximum turbidity was generated when operating at pH = 2.0, and it slowly decreased with increasing to a value of pH = 3.0, at which the turbidity was the lowest. This result was a consequence of the presence of ferric ions in solution. At pH values greater than 3.5, the turbidity increased almost linearly until at pH = 5.0 reached its maximum intensity. In this range, ferrous ions may generate an additional contribution of radicals that promote the degradation of the phenol species that produce turbidity. Turbidity was enhanced at ratios R = 4.0 mol H 2 O 2 /mol C 6 H 6 O. This value corresponds to the stoichiometric ratio that leads to the production of turbidity-precursor species. Therefore, muconic acid would be a species that generate high turbidity in solution according to its isomerism. Also, the results revealed that the turbidity is not a parameter to which species contribute additively since interactions may occur among species that would enhance their individual contributions to it. Analyzing the oxidation of phenol degradation intermediates, the results showed that meta-substituted compounds (resorcinol) generate high turbidity in the wastewater. The presence of polar molecules, such as muconic acid, would provide the structural features that are necessary for resorcinol to act as a clip between two carboxylic groups, thus establishing

  12. Cationic Copolymerization of 3,3-Bis(hydroxymethyl)oxetane and Glycidol: Biocompatible Hyperbranched Polyether Polyols with High Content of Primary Hydroxyl Groups.

    Science.gov (United States)

    Christ, Eva-Maria; Hobernik, Dominika; Bros, Matthias; Wagner, Manfred; Frey, Holger

    2015-10-12

    The cationic ring-opening copolymerization of 3,3-bis(hydroxymethyl)oxetane (BHMO) with glycidol using different comonomer ratios (BHMO content from 25 to 90%) and BF3OEt2 as an initiator has been studied. Apparent molecular weights of the resulting hyperbranched polyether copolymers ranged from 1400 to 3300 g mol(-1) (PDI: 1.21-1.48; method: SEC, linear PEG standards). Incorporation of both comonomers is evidenced by MALDI-TOF mass spectroscopy. All hyperbranched polyether polyols with high content of primary hydroxyl groups portray good solubility in water, which correlates with an increasing content of glycerol units. Detailed NMR characterization was employed to elucidate the copolymer microstructures. Kinetic studies via FTIR demonstrated a weak gradient-type character of the copolymers. MTT assays of the copolymers (up to 100 μg mL(-1)) on HEK and fibroblast cell lines (3T3, L929, WEHI) as well as viability tests on the fibroblast cells were carried out to assess the biocompatibility of the materials, confirming excellent biocompatibility. Transfection efficiency characterization by flow cytometry and confocal laser microscopy demonstrated cellular uptake of the copolymers. Antiadhesive properties of the materials on surfaces were assessed by adhesion assays with fibroblast cells.

  13. The influence of surface oxygen and hydroxyl groups on the dehydrogenation of ethylene, acetic acid and hydrogenated vinyl acetate on pure Pd(1 0 0): A DFT study

    Energy Technology Data Exchange (ETDEWEB)

    Huang, Yanping [Key Laboratory for Green Chemical Technology of Ministry of Education, R& D Center for Petrochemical Technology, Tianjin University, Tianjin (China); Collaborative Innovation Center of Chemical Science and Engineering, Tianjin 300072 (China); Dong, Xiuqin [Key Laboratory for Green Chemical Technology of Ministry of Education, R& D Center for Petrochemical Technology, Tianjin University, Tianjin (China); Yu, Yingzhe, E-mail: yzhyu@tju.edu.cn [Key Laboratory for Green Chemical Technology of Ministry of Education, R& D Center for Petrochemical Technology, Tianjin University, Tianjin (China); Zhang, Minhua, E-mail: mhzhangtj@163.com [Key Laboratory for Green Chemical Technology of Ministry of Education, R& D Center for Petrochemical Technology, Tianjin University, Tianjin (China)

    2016-12-01

    Highlights: • All dehydrogenation reactions in vinyl acetate synthesis on Pd(1 0 0) were studied. • The energy barriers of the transition state of the three reactions were calculated. • The influence of surface Os and OHs on all dehydrogenation actions was discussed. - Abstract: On the basis of a Langmuir–Hinshelwood-type mechanism, the dehydrogenation of ethylene, acetic acid and hydrogenated vinyl acetate (VAH) on pure Pd(1 0 0) with surface oxygen atoms (Os) and hydroxyl groups (OHs) was studied with density functional theory (DFT) method. Our calculation results show that both Os and OHs can consistently reduce the activation energies of dehydrogenation of ethylene, acetic acid and VAH to some degree with only one exception that OHs somehow increase the activation energy of VAH. Based on Langmuir–Hinshelwood mechanism, the three dehydrogenation reactions in presence of surface Os and OHs are almost consistently favored, compared with the corresponding processes on clean Pd(1 0 0) surfaces, and thus a Langmuir–Hinshelwood-type mechanism may not be excluded beforehand when investigating the microscopic performance of the oxygen-assisted vinyl acetate synthesis on Pd(1 0 0) catalysts.

  14. Metal accumulation and antioxidant defenses in the freshwater fish Carassius auratus in response to single and combined exposure to cadmium and hydroxylated multi-walled carbon nanotubes

    International Nuclear Information System (INIS)

    Qu, Ruijuan; Wang, Xinghao; Wang, Zunyao; Wei, Zhongbo; Wang, Liansheng

    2014-01-01

    Highlights: • Cd and OH-MWCNTs have a synergistic effect on Carassius auratus. • OH-MWCNTs significantly increased Cd accumulation in liver after 12 d exposure. • Co-exposure to Cd and OH-MWCNTs evoked severe hepatic oxidative stress. - Abstract: The effects of cadmium, hydroxylated multi-walled carbon nanotubes, and their mixture on metal accumulation and antioxidant defenses were studied using the goldfish Carassius auratus as the test organism. The fish were exposed to 0.1 mg/L Cd, 0.5 mg/L OH-MWCNTs, or 0.1 mg/L Cd + 0.5 mg/L OH-MWCNTs for 3 and 12 days. Then, the Cd concentration was determined in the gill, liver and muscle. Moreover, hepatic antioxidant enzyme activity (superoxide dismutase, catalase and glutathione peroxidase), glutathione level and malondialdehyde content were also measured. A continuous accumulation of Cd was observed throughout the experimental period. Cd accumulation in tissues occurred in the following order: gill > liver > muscle at 3 days and liver > gill > muscle at 12 days. The concentrations of Cd in the livers of fish exposed to the combination of Cd + OH-MWCNTs were significantly higher than those in fish exposed to either single chemical after 12 d of exposure. Meanwhile, the mixture evoked severe oxidative stress in the exposed fish, as indicated by significant inhibition of SOD, CAT and GPx activity, a remarkable decrease in GSH level, and simultaneous elevation of MDA content. These results suggested that the effect of the combined factors on metal accumulation and oxidative stress biomarkers was more obvious than that of single factors at longer exposure durations

  15. Metal accumulation and antioxidant defenses in the freshwater fish Carassius auratus in response to single and combined exposure to cadmium and hydroxylated multi-walled carbon nanotubes

    Energy Technology Data Exchange (ETDEWEB)

    Qu, Ruijuan; Wang, Xinghao; Wang, Zunyao, E-mail: wangzun315cn@163.com; Wei, Zhongbo; Wang, Liansheng

    2014-06-30

    Highlights: • Cd and OH-MWCNTs have a synergistic effect on Carassius auratus. • OH-MWCNTs significantly increased Cd accumulation in liver after 12 d exposure. • Co-exposure to Cd and OH-MWCNTs evoked severe hepatic oxidative stress. - Abstract: The effects of cadmium, hydroxylated multi-walled carbon nanotubes, and their mixture on metal accumulation and antioxidant defenses were studied using the goldfish Carassius auratus as the test organism. The fish were exposed to 0.1 mg/L Cd, 0.5 mg/L OH-MWCNTs, or 0.1 mg/L Cd + 0.5 mg/L OH-MWCNTs for 3 and 12 days. Then, the Cd concentration was determined in the gill, liver and muscle. Moreover, hepatic antioxidant enzyme activity (superoxide dismutase, catalase and glutathione peroxidase), glutathione level and malondialdehyde content were also measured. A continuous accumulation of Cd was observed throughout the experimental period. Cd accumulation in tissues occurred in the following order: gill > liver > muscle at 3 days and liver > gill > muscle at 12 days. The concentrations of Cd in the livers of fish exposed to the combination of Cd + OH-MWCNTs were significantly higher than those in fish exposed to either single chemical after 12 d of exposure. Meanwhile, the mixture evoked severe oxidative stress in the exposed fish, as indicated by significant inhibition of SOD, CAT and GPx activity, a remarkable decrease in GSH level, and simultaneous elevation of MDA content. These results suggested that the effect of the combined factors on metal accumulation and oxidative stress biomarkers was more obvious than that of single factors at longer exposure durations.

  16. DNA Binding Hydroxyl Radical Probes.

    Science.gov (United States)

    Tang, Vicky J; Konigsfeld, Katie M; Aguilera, Joe A; Milligan, Jamie R

    2012-01-01

    The hydroxyl radical is the primary mediator of DNA damage by the indirect effect of ionizing radiation. It is a powerful oxidizing agent produced by the radiolysis of water and is responsible for a significant fraction of the DNA damage associated with ionizing radiation. There is therefore an interest in the development of sensitive assays for its detection. The hydroxylation of aromatic groups to produce fluorescent products has been used for this purpose. We have examined four different chromophores which produce fluorescent products when hydroxylated. Of these, the coumarin system suffers from the fewest disadvantages. We have therefore examined its behavior when linked to a cationic peptide ligand designed to bind strongly to DNA.

  17. Effect of the number of phenyl groups per molecule on the reactivity of hydroxyl or carboxyl group in hydrogen-isotope exchange reaction

    International Nuclear Information System (INIS)

    Okada, Minoru; Imaizumi, Hiroshi; Oguma, Shuichi

    1989-01-01

    Hydrogen-exchange reactions in solid alcohols (or solid carboxylic acids) which contain phenyl group(s) in each molecule have been observed in a gas-solid system or liquid-solid system at 40 ≅ 80deg C. The data thus obtained have been analyzed by using the A''-McKay plot method, and 'the acidities based on kinetic logic' have been obtained for those compounds. From the acidities the following four characteristics have been determined. (1) The acidity increases with increases of temperature. (2) The reactivities of carboxylic acids are larger than those of alcohols at any temperature. (3) The effect of the number of phenyl groups on the reactivity of the functional group in the molecule in question is fairly large. (4) Acidity based on kinetic logic can be applied not only to gas-solid reactions, but also to liquid-solid reactions. (orig.)

  18. Cultural Values in Intergroup and Single-Group Social Dilemmas.

    Science.gov (United States)

    Probst; Carnevale; Triandis

    1999-03-01

    Do cultural values influence the manner in which people cooperate with one another? This study assessed cultural characteristics of individuals and then related these characteristics to cooperative behavior in social dilemmas. Participants were assessed for their degree of vertical and horizontal individualism and collectivism, cultural values identified by Triandis (1995). They made choices in either a single-group or an intergroup social dilemma. The single-group dilemma entailed a three-person dilemma; the intergroup dilemma was identical but added subgroup competition, i.e., an opposing three-person group. The results indicated an interaction between cultural characteristics and type of dilemma for cooperation. The single-group versus intergroup effect reported by Bornstein and Ben-Yossef (1994) was replicated, but only for vertical individualists. The vertical individualists were least cooperative in the single-group dilemma but were more cooperative in the intergroup dilemma-where cooperation with the group maximized personal outcomes. The vertical collectivists were most cooperative in the single-group dilemma but were less cooperative in the intergroup dilemma- where group defection resulted in maximum group outcomes. The horizontal individualists and collectivists exhibited an intermediate level of cooperation, with no differences in cooperation between the single-group and intergroup dilemmas. Taken together, the results suggest that the relationship between cultural values and cooperation, in particular with reference to vertical and horizontal components of individualism and collectivism, is more complex than has been suggested in past research. Copyright 1999 Academic Press.

  19. The effect of hydroxyl functional groups and molar mass on the viscosity of non-crystalline organic and organic–water particles

    Directory of Open Access Journals (Sweden)

    J. W. Grayson

    2017-07-01

    Full Text Available The viscosities of three polyols and three saccharides, all in the non-crystalline state, have been studied. Two of the polyols (2-methyl-1,4-butanediol and 1,2,3-butanetriol were studied under dry conditions, the third (1,2,3,4-butanetetrol was studied as a function of relative humidity (RH, including under dry conditions, and the saccharides (glucose, raffinose, and maltohexaose were studied as a function of RH. The mean viscosities of the polyols under dry conditions range from 1.5  ×  10−1 to 3.7  ×  101 Pa s, with the highest viscosity being that of the tetrol. Using a combination of data determined experimentally here and literature data for alkanes, alcohols, and polyols with a C3 to C6 carbon backbone, we show (1 there is a near-linear relationship between log10 (viscosity and the number of hydroxyl groups in the molecule, (2 that on average the addition of one OH group increases the viscosity by a factor of approximately 22 to 45, (3 the sensitivity of viscosity to the addition of one OH group is not a strong function of the number of OH functional groups already present in the molecule up to three OH groups, and (4 higher sensitivities are observed when the molecule has more than three OH groups. Viscosities reported here for 1,2,3,4-butanetetrol particles are lower than previously reported measurements using aerosol optical tweezers, and additional studies are required to resolve these discrepancies. For saccharide particles at 30 % RH, viscosity increases by approximately 2–5 orders of magnitude as molar mass increases from 180 to 342 g mol−1, and at 80 % RH, viscosity increases by approximately 4–5 orders of magnitude as molar mass increases from 180 to 991 g mol−1. These results suggest oligomerization of highly oxidized compounds in atmospheric secondary organic aerosol (SOA could lead to large increases in viscosity, and may be at least partially responsible for the high

  20. Determination of the pKa value of the hydroxyl group in the alpha-hydroxycarboxylates citrate, malate and lactate by 13C NMR: implications for metal coordination in biological systems.

    Science.gov (United States)

    Silva, Andre M N; Kong, XiaoLe; Hider, Robert C

    2009-10-01

    Citric acid is an important metal chelator of biological relevance. Citric acid helps solubilizing metals, increasing their bioavailability for plants and microbes and it is also thought to be a constituent of both the extracellular and cytoplasmic low molecular iron pools occurring in plants and vertebrates. Metal coordination by citric acid involves coordination both by the carboxylate and hydroxyl groups, of particular interest is its alpha-hydroxycarboxylate function. This structural feature is highly conserved in siderophores produced by evolutionarily distant species and seems to confer specificity toward Fe(III) binding. In order to understand the mechanism of metal coordination by alpha-hydroxycarboxylates and correctly evaluate the respective complex stability constants, it is essential to improve the knowledge about the ionisation of the alcohol group in these compounds. We have evaluated the hydroxyl pKa value of citric, malic and lactic acids with the objective of understanding the influence of alpha-carbon substitution. Studies at high pH values, utilizing (13)C NMR, permitted estimation of the pKa values for the three acids. The pKa (alcohol) values (14.4 for citric acid, 14.5 for malic acid, and 15.1 for lactic acid) are considerably higher than the previously reported value for citric acid (11.6) but still lower than the value of 15.5 for methanol. A comparative analysis of the three compounds indicates that different substitutions on the alpha-carbon introduce changes to the inductive effect experienced by the hydroxyl group thereby modulating its ionisation behaviour. Comparison with the siderophore rhizoferrin, which pKa (alcohol) values were confirmed to be 10 and 11.3, suggests that intra-molecular hydrogen bonding may also aid in the hydroxyl ionisation by stabilizing the resulting anion. Studies of metal coordination by alpha-hydroxycarboxylates should take these factors into account.

  1. A Community Support Group for Single Custodial Fathers.

    Science.gov (United States)

    Tedder, Sandra L.; And Others

    1981-01-01

    Discusses a five-session group experience within the context of establishing a support group for single custodial fathers. Includes topics of dating, remarriage, homemaking and house maintenance, and the effects of divorce on children. A follow-up showed fathers appreciated the sense of community and specific information and coping strategies.…

  2. Multi-group dynamic quantum secret sharing with single photons

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Hongwei [School of Science and State Key Laboratory of Information Photonics and Optical Communications, Beijing University of Posts and Telecommunications, Beijing 100876 (China); Ma, Haiqiang, E-mail: hqma@bupt.edu.cn [School of Science and State Key Laboratory of Information Photonics and Optical Communications, Beijing University of Posts and Telecommunications, Beijing 100876 (China); Wei, Kejin [School of Science and State Key Laboratory of Information Photonics and Optical Communications, Beijing University of Posts and Telecommunications, Beijing 100876 (China); Yang, Xiuqing [School of Science, Beijing Jiaotong University, Beijing 100044 (China); Qu, Wenxiu; Dou, Tianqi; Chen, Yitian; Li, Ruixue; Zhu, Wu [School of Science and State Key Laboratory of Information Photonics and Optical Communications, Beijing University of Posts and Telecommunications, Beijing 100876 (China)

    2016-07-15

    In this letter, we propose a novel scheme for the realization of single-photon dynamic quantum secret sharing between a boss and three dynamic agent groups. In our system, the boss can not only choose one of these three groups to share the secret with, but also can share two sets of independent keys with two groups without redistribution. Furthermore, the security of communication is enhanced by using a control mode. Compared with previous schemes, our scheme is more flexible and will contribute to a practical application. - Highlights: • A multi-group dynamic quantum secret sharing with single photons scheme is proposed. • Any one of the groups can be chosen to share secret through controlling the polarization of photons. • Two sets of keys can be shared simultaneously without redistribution.

  3. Photoinduced nuclear spin conversion of methyl groups of single molecules

    International Nuclear Information System (INIS)

    Sigl, A.

    2007-01-01

    A methyl group is an outstanding quantum system due to its special symmetry properties. The threefold rotation around one of its bond is isomorphic to the group of even permutations of the remaining protons, a property which imposes severe quantum restrictions on the system, for instance a strict correlation of rotational states with nuclear spin states. The resulting long lifetimes of the rotational tunneling states of the methyl group can be exploited for applying certain high resolution optical techniques, like hole burning or single molecule spectroscopy to optically switch the methyl group from one tunneling state to another therebye changing the nuclear spin of the protons. One goal of the thesis was to perform this switching in single methyl groups. To this end the methyl group was attached to a chromophoric system, in the present case terrylene, which is well suited for single molecule spectroscopy as well as for hole burning. Experiments were performed with the bare terrylene molecule in a hexadecane lattice which served as a reference system, with alphamethyl terrylene and betamethyl terrylene, both embedded in hexadecane, too. A single molecular probe is a highly sensitive detector for dynamic lattice instabilities. Already the bare terrylene probe showed a wealth of interesting local dynamic effects of the hexadecane lattice which could be well acounted for by the assumption of two nearly degenerate sites with rather different optical and thermal properties, all of which could be determined in a quantitative fashion. As to the methylated terrylene systems, the experiments verified that for betamethyl terrylene it is indeed possible to measure rotational tunneling events in single methyl groups. However, the spectral patterns obtained was much more complicated than expected pointing to the presence of three spectroscopically different methyl groups. In order to achieve a definite assignement, molecular mechanics simulations of the terrylene probes in the

  4. A new method for immediate derivatization of hydroxyl groups by fluoroalkyl chloroformates and its application for the determination of sterols and tocopherols in human serum and amniotic fluid by gas chromatography-mass spectrometry

    Czech Academy of Sciences Publication Activity Database

    Řimnáčová, Lucie; Hušek, Petr; Šimek, Petr

    2014-01-01

    Roč. 1339, APR 25 (2014), s. 154-167 ISSN 0021-9673 R&D Projects: GA MZd(CZ) NT11513 Grant - others:Czech Science Foundation(CZ) P206-10-2401; Grant Agency of Charles University(CZ) 54009 Institutional support: RVO:60077344 Keywords : alkyl chlorformate derivatization * steroid hydroxyl group * liquid-liquid microextraction Subject RIV: CB - Analytical Chemistry , Separation Impact factor: 4.169, year: 2014 http://www.sciencedirect.com/science/article/pii/S0021967314003707

  5. Single or functionalized fullerenes interacting with heme group

    Energy Technology Data Exchange (ETDEWEB)

    Costa, Wallison Chaves; Diniz, Eduardo Moraes, E-mail: eduardo.diniz@ufma.br [Departamento de Física, Universidade Federal do Maranhão, Avenida dos Portugueses, 1966, CEP 65080-805, São Luís - MA (Brazil)

    2014-09-15

    The heme group is responsible for iron transportation through the bloodstream, where iron participates in redox reactions, electron transfer, gases detection etc. The efficiency of such processes can be reduced if the whole heme molecule or even the iron is somehow altered from its original oxidation state, which can be caused by interactions with nanoparticles as fullerenes. To verify how such particles alter the geometry and electronic structure of heme molecule, here we report first principles calculations based on density functional theory of heme group interacting with single C{sub 60} fullerene or with C{sub 60} functionalized with small functional groups (−CH{sub 3}, −COOH, −NH{sub 2}, −OH). The calculations shown that the system heme + nanoparticle has a different spin state in comparison with heme group if the fullerene is functionalized. Also a functional group can provide a stronger binding between nanoparticle and heme molecule or inhibit the chemical bonding in comparison with single fullerene results. In addition heme molecule loses electrons to the nanoparticles and some systems exhibited a geometry distortion in heme group, depending on the binding energy. Furthermore, one find that such nanoparticles induce a formation of spin up states in heme group. Moreover, there exist modifications in density of states near the Fermi energy. Although of such changes in heme electronic structure and geometry, the iron atom remains in the heme group with the same oxidation state, so that processes that involve the iron might not be affected, only those that depend on the whole heme molecule.

  6. Microarray Beads for Identifying Blood Group Single Nucleotide Polymorphisms

    OpenAIRE

    Drago, Francesca; Karpasitou, Katerina; Poli, Francesca

    2009-01-01

    We have developed a high-throughput system for single nucleotide polymorphism (SNP) genotyping of alleles of diverse blood group systems exploiting Luminex technology. The method uses specific oligonucleotide probes coupled to a specific array of fluorescent microspheres and is designed for typing Jka/Jkb, Fya/Fyb, S/s, K/k, Kpa/Kpb, Jsa/Jsb, Coa/Cob and Lua/Lub alleles. Briefly, two multiplex PCR reactions (PCR I and PCR II) according to the laboratory specific needs are set up. PCR I amplif...

  7. Microarray Beads for Identifying Blood Group Single Nucleotide Polymorphisms.

    Science.gov (United States)

    Drago, Francesca; Karpasitou, Katerina; Poli, Francesca

    2009-01-01

    We have developed a high-throughput system for single nucleotide polymorphism (SNP) genotyping of alleles of diverse blood group systems exploiting Luminex technology. The method uses specific oligonucleotide probes coupled to a specific array of fluorescent microspheres and is designed for typing Jk(a)/Jk(b), Fy(a)/Fy(b), S/s, K/k, Kp(a)/Kp(b), Js(a)/Js(b), Co(a)/Co(b) and Lu(a)/Lu(b) alleles. Briefly, two multiplex PCR reactions (PCR I and PCR II) according to the laboratory specific needs are set up. PCR I amplifies the alleles tested routinely, namely Jk(a)/Jk(b), Fy(a)/Fy(b), S/s, and K/k. PCR II amplifies those alleles that are typed less frequently. Biotinylated PCR products are hybridized in a single multiplex assay with the corresponding probe mixture. After incubation with R-phycoerythrin-conjugated streptavidin, the emitted fluorescence is analyzed with Luminex 100. So far, we have typed more than 2,000 subjects, 493 of whom with multiplex assay, and there have been no discrepancies with the serology results other than null and/or weak phenotypes. The cost of consumables and reagents for typing a single biallelic pair per sample is less than EUR 3.-, not including DNA extraction costs. The capability to perform multiplexed reactions makes the method markedly suitable for mass screening of red blood cell alleles. This genotyping approach represents an important tool in transfusion medicine.

  8. Renormalisation group analysis of single right-handed neutrino dominance

    International Nuclear Information System (INIS)

    King, S.F.; Nimai Singh, N.

    2000-01-01

    We perform a renormalisation group (RG) analysis of neutrino masses and mixing angles in the see-saw mechanism in the minimal supersymmetric standard model with three right-handed neutrinos, including the effects of the heavy neutrino thresholds. We focus on the case that one of the right-handed neutrinos provides the dominant contribution to the 23 block of the light Majorana matrix, causing its determinant to approximately vanish and giving an automatic neutrino mass hierarchy, so-called single right-handed neutrino dominance which may arise from a U(1) family symmetry. In these models radiative corrections can increase atmospheric and solar neutrino mixing by up to about 10% and 5%, respectively, and may help to achieve bi-maximal mixing. Significantly we find that the radiative corrections over the heavy neutrino threshold region are at least as important as those usually considered from the lightest right-handed neutrino down to low energies

  9. Single electron detachment of carbon group and oxygen group elements incident on helium

    International Nuclear Information System (INIS)

    Huang Yongyi; Li Guangwu; Gao Yinghui; Yang Enbo; Gao Mei; Lu Fuquan; Zhang Xuemei

    2006-01-01

    The absolute single electron detachment (SED) cross sections of carbon group elements C - , Si - , Ge - in the energy range of 0.05-0.29 a.u. (5 keV-30 keV) and oxygen group elements O - and S - 0.08-0.27 a.u. (5 keV-30 keV), incident on helium are measured with growth rate method. In our energy region, the SED cross sections of C - , Si - , S - and Ge - increase with the projectiles velocity, at the same time, O - cross sections reach a conspicuous maximum at 0.18 a.u. Some abnormal behavior occurs in measurement of SED cross sections for the oxygen group collision with helium. Our results have been compared with a previous work

  10. New and extended parameterization of the thermodynamic model AIOMFAC: calculation of activity coefficients for organic-inorganic mixtures containing carboxyl, hydroxyl, carbonyl, ether, ester, alkenyl, alkyl, and aromatic functional groups

    Directory of Open Access Journals (Sweden)

    A. Zuend

    2011-09-01

    Full Text Available We present a new and considerably extended parameterization of the thermodynamic activity coefficient model AIOMFAC (Aerosol Inorganic-Organic Mixtures Functional groups Activity Coefficients at room temperature. AIOMFAC combines a Pitzer-like electrolyte solution model with a UNIFAC-based group-contribution approach and explicitly accounts for interactions between organic functional groups and inorganic ions. Such interactions constitute the salt-effect, may cause liquid-liquid phase separation, and affect the gas-particle partitioning of aerosols. The previous AIOMFAC version was parameterized for alkyl and hydroxyl functional groups of alcohols and polyols. With the goal to describe a wide variety of organic compounds found in atmospheric aerosols, we extend here the parameterization of AIOMFAC to include the functional groups carboxyl, hydroxyl, ketone, aldehyde, ether, ester, alkenyl, alkyl, aromatic carbon-alcohol, and aromatic hydrocarbon. Thermodynamic equilibrium data of organic-inorganic systems from the literature are critically assessed and complemented with new measurements to establish a comprehensive database. The database is used to determine simultaneously the AIOMFAC parameters describing interactions of organic functional groups with the ions H+, Li+, Na+, K+, NH4+, Mg2+, Ca2+, Cl, Br, NO3, HSO4, and SO42−. Detailed descriptions of different types of thermodynamic data, such as vapor-liquid, solid-liquid, and liquid-liquid equilibria, and their use for the model parameterization are provided. Issues regarding deficiencies of the database, types and uncertainties of experimental data, and limitations of the model, are discussed. The challenging parameter optimization problem is solved with a novel combination of powerful global minimization

  11. Hydroxyl-dependent Evolution of Oxygen Vacancies Enables the Regeneration of BiOCl photocatalyst

    KAUST Repository

    Wu, Sujuan; Xiong, Jiawei; Sun, Jianguo; Hood, Zachary D.; Zeng, Wen; Yang, Zhenzhong; Gu, Lin; Zhang, Xixiang; Yang, Shize

    2017-01-01

    irradiation in the sample with surface hydroxyl groups, while variable changes were observed in samples without surface hydroxyls. Density functional theory (DFT) calculations reveal that the binding energy of Bi-O is drastically influenced by surficial

  12. Atomic geometry and STM simulations of a TiO.sub.2./sub.(110) surface upon formation of an oxygen vacancy and hydroxyl group

    Czech Academy of Sciences Publication Activity Database

    Mutombo, Pingo; Kiss, A.M.; Berkó, A.; Cháb, Vladimír

    2008-01-01

    Roč. 16, - (2008), 025007/1-025007/9 ISSN 0965-0393 R&D Projects: GA AV ČR IAA1010413 Grant - others:MŠMT(CZ) 9/2004 KONTAKT Institutional research plan: CEZ:AV0Z10100521 Source of funding: V - iné verejné zdroje Keywords : vacance * Oxygen * OH group * STM Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 1.388, year: 2008

  13. Isolated and Single Pedestrians and Pedestrian Groups on Sidewalks

    Directory of Open Access Journals (Sweden)

    Francesco Pinna

    2017-11-01

    Full Text Available Walking freedom can define the quality of an urban area, but this freedom is conditioned by various factors. The research objective is to study pedestrian behavior on sidewalks. Data are collected during on site surveys by means of concealed camcorders. For each pedestrian many factors are observed, such as gender, age, direction, distractions, transport of objects, etc., which could influence pedestrian behavior. Data processing allows the identification of mathematical models describing the average pedestrian’s behavior, subdivided for user type (isolated, single, group. In general, the mean walking pedestrian speed decreases depending on user type (in a linear manner if age class grows for isolated pedestrians, while with the square of age for other user types, of gender, and of facing type. Models obtained for the different pedestrian types were compared to understand the differences in speeds, underlining that pedestrian interferences play a significant role in defining behavior and, therefore, speed. The results support the idea that, to define a smooth pedestrian speed as an indicator of the “walkability” of a path, in addition to considering the path and user’s characteristics, it is also necessary to define the type of user for which the infrastructure is designed.

  14. Hydroxyl radical reactivity with diethylhydroxylamine

    International Nuclear Information System (INIS)

    Gorse, R.A. Jr.; Lii, R.R.; Saunders, B.B.

    1977-01-01

    Diethylhydroxylamine (DEHA) reacts with gas-phase hydroxyl radicals on every third collision, whereas the corresponding reaction in aqueous solution is considerably slower. The high gas-phase reactivity explains the predicted inhibitory effect of DEHA in atmospheric smog processes. Results from the studies in the aqueous phase are helpful in predicting the mechanism of the reaction of DEHA with hydroxyl radicals

  15. Intracrystalline fractionation of oxygen isotopes between hydroxyl and non-hydroxyl sites in kaolinite measured by thermal dehydroxylation and partial fluorination

    Science.gov (United States)

    Girard, Jean-Pierre; Savin, Samuel M.

    1996-02-01

    Thermal dehydroxylation and partial fluorination techniques were used to measure intracrystalline fractionation of oxygen isotopes between hydroxyl and non-hydroxyl sites in kaolinite. Several aliquots of a well characterized, fine-grained (rates, and target temperatures. Measured δ18O values of both the liberated water and the dehydroxylated residue are consistent over a wide range of temperatures (550 850°C) when dehydroxylation is performed in a single-step fashion at a rapid heating rate (>50°C/min.). Similar dehydroxylation experiments indicate that brucite dehydroxylation occurs without any significant isotopic fractionation of the oxygen isotopes. By extrapolation we postulate that no significant fractionation occurs during single-step thermal dehydroxylation of fine-grained kaolinite, provided that dehydroxylation is performed under well controlled conditions. In contrast, gibbsite dehydroxylation is accompanied by substantial isotopic fractionation. This is probably the result of the complex, multi-pathway dehydroxylation reaction of this mineral. Similarly, thermal dehydroxylation of coarsegrained (>1 μm) kaolinites and dickites of weathering and hydrothermal origin yield results that are dependent on the temperature of dehydroxylation. We suggest that this effect may be caused by isotopic exchange during diffusion of water molecules through coarse particles. Partial fluorination of fine-grained kaolinite in the presence of excess F2 at low temperatures (rate of reaction of hydroxyl oxygen than of non-hydroxyl oxygen, but examination of the isotopic data as well as XRD and IR analyses of the residues after partial fluorination indicates that the separation between the two types of oxygen is not complete. The results, therefore, do not yield a reliable δ18O value of the hydroxyl oxygen. The results of this study suggest that the thermal dehydroxylation technique may be appropriate for analysis of OH groups in fine-grained kaolinite. The partial

  16. Hydroxylated PBDEs induce developmental arrest in zebrafish

    Energy Technology Data Exchange (ETDEWEB)

    Usenko, Crystal Y., E-mail: Crystal_usenko@baylor.edu; Hopkins, David C.; Trumble, Stephen J., E-mail: Stephen_trumble@baylor.edu; Bruce, Erica D., E-mail: Erica_bruce@baylor.edu

    2012-07-01

    The ubiquitous spread of polybrominated diphenyl ethers (PBDEs) has led to concerns regarding the metabolites of these congeners, in particular hydroxylated PBDEs. There are limited studies regarding the biological interactions of these chemicals, yet there is some concern they may be more toxic than their parent compounds. In this study three hydroxylated PBDEs were assessed for toxicity in embryonic zebrafish: 3-OH-BDE 47, 5-OH-BDE 47, and 6-OH-BDE 47. All three congeners induced developmental arrest in a concentration-dependent manner; however, 6-OH-BDE 47 induced adverse effects at lower concentrations than the other congeners. Furthermore, all three induced cell death; however apoptosis was not observed. In short-term exposures (24–28 hours post fertilization), all hydroxylated PBDEs generated oxidative stress in the region corresponding to the cell death at 5 and 10 ppm. To further investigate the short-term effects that may be responsible for the developmental arrest observed in this study, gene regulation was assessed for embryos exposed to 0.625 ppm 6-OH-BDE 47 from 24 to 28 hpf. Genes involved in stress response, thyroid hormone regulation, and neurodevelopment were significantly upregulated compared to controls; however, genes related to oxidative stress were either unaffected or downregulated. This study suggests that hydroxylated PBDEs disrupt development, and may induce oxidative stress and potentially disrupt the cholinergic system and thyroid hormone homeostasis. -- Highlights: ► OH-PBDEs induce developmental arrest in a concentration-dependent manner. ► Hydroxyl group location influences biological interaction. ► OH-PBDEs induce oxidative stress. ► Thyroid hormone gene regulation was disrupted following exposure. ► To our knowledge, this is the first whole organism study of OH-PBDE toxicity.

  17. Water-soluble light-emitting nanoparticles prepared by non-covalent bond self-assembly of a hydroxyl group functionalized oligo(p-phenyleneethynylene) with different water-soluble polymers

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    Water-soluble light-emitting nanoparticles were prepared from hydroxyl group functionalized oligos(p-phenyleneethynylene) (OHOPEL) and water-soluble polymers(PEG,PAA,and PG) by non-covalent bond self-assembly.Their structure and optoelectronic properties were investigated through dynamic light scattering(DLS) ,UV and PL spectroscopy.The optical properties of OHOPEL-based water-soluble nanoparticles exhibited the same properties as that found in OHOPEL films,indicating the existence of interchain-aggregation of OHOPELs in the nanoparticles.OHOPEL-based nanoparticles prepared from conjugated oligomers show smaller size and lower dispersity than nanoparticles from conjugated polymers,which means that the structures of water-soluble nanoparticles are linked to the conjugated length.Furthermore,the OHOPEL/PG and OHOPEL/PAA systems produced smaller particles and lower polydispersity than the OHOPEL/PEG system,indicating that there may exist influence of the strength of non-covalent bonds on the size and degree of dispersity of the nanoparticles.

  18. Group one impurities in single crystalline Zinc Oxide

    OpenAIRE

    Johansen, Klaus Magnus Håland

    2011-01-01

    Zinc Oxide (ZnO) has been used as a material in many different technologies from pharmaceuticals to electronics. This exciting material can also be utilized as a wide band gap semiconductor for application in optoelectronic devices. The availability of Zn, the possibility to grow single crystal bulk material and the exitonic binding energy of 60 meV makes this material especially interesting. Even though the material has been studied already since the late 1920s there are still some fundament...

  19. Hydroxyl radical induced degradation of ibuprofen

    Energy Technology Data Exchange (ETDEWEB)

    Illés, Erzsébet, E-mail: erzsebet.illes@chem.u-szeged.hu [Institute of Chemistry, Research Group of Environmental Chemistry, University of Szeged, Szeged (Hungary); Institute of Isotopes, Centre for Energy Research, Hungarian Academy of Sciences, Budapest (Hungary); Takács, Erzsébet [Institute of Isotopes, Centre for Energy Research, Hungarian Academy of Sciences, Budapest (Hungary); Dombi, András [Institute of Chemistry, Research Group of Environmental Chemistry, University of Szeged, Szeged (Hungary); Gajda-Schrantz, Krisztina [Institute of Chemistry, Research Group of Environmental Chemistry, University of Szeged, Szeged (Hungary); Department of Inorganic and Analytical Chemistry, University of Szeged, Szeged (Hungary); EMPA, Laboratory for High Performance Ceramics, Duebendorf (Switzerland); Rácz, Gergely; Gonter, Katalin; Wojnárovits, László [Institute of Isotopes, Centre for Energy Research, Hungarian Academy of Sciences, Budapest (Hungary)

    2013-03-01

    Pulse radiolysis experiments were used to characterize the intermediates formed from ibuprofen during electron beam irradiation in a solution of 0.1 mmol dm{sup −3}. For end product characterization {sup 60}Co γ-irradiation was used and the samples were evaluated either by taking their UV–vis spectra or by HPLC with UV or MS detection. The reactions of {sup ·}OH resulted in hydroxycyclohexadienyl type radical intermediates. The intermediates produced in further reactions hydroxylated the derivatives of ibuprofen as final products. The hydrated electron attacked the carboxyl group. Ibuprofen degradation is more efficient under oxidative conditions than under reductive conditions. The ecotoxicity of the solution was monitored by Daphnia magna standard microbiotest and Vibrio fischeri luminescent bacteria test. The toxic effect of the aerated ibuprofen solution first increased upon irradiation indicating a higher toxicity of the first degradation products, then decreased with increasing absorbed dose. Highlights: ► In hydroxyl radical attack on the ring mainly hydroxylated products form ► The hydrated electron attacks the carboxyl group. ► Oxidative conditions are more effective in ibuprofen decomposition than reductive. ► Ecotoxicity of ibuprofen solution first increases then decreases with irradiation.

  20. Hydroxyl radical induced degradation of ibuprofen

    International Nuclear Information System (INIS)

    Illés, Erzsébet; Takács, Erzsébet; Dombi, András; Gajda-Schrantz, Krisztina; Rácz, Gergely; Gonter, Katalin; Wojnárovits, László

    2013-01-01

    Pulse radiolysis experiments were used to characterize the intermediates formed from ibuprofen during electron beam irradiation in a solution of 0.1 mmol dm −3 . For end product characterization 60 Co γ-irradiation was used and the samples were evaluated either by taking their UV–vis spectra or by HPLC with UV or MS detection. The reactions of · OH resulted in hydroxycyclohexadienyl type radical intermediates. The intermediates produced in further reactions hydroxylated the derivatives of ibuprofen as final products. The hydrated electron attacked the carboxyl group. Ibuprofen degradation is more efficient under oxidative conditions than under reductive conditions. The ecotoxicity of the solution was monitored by Daphnia magna standard microbiotest and Vibrio fischeri luminescent bacteria test. The toxic effect of the aerated ibuprofen solution first increased upon irradiation indicating a higher toxicity of the first degradation products, then decreased with increasing absorbed dose. Highlights: ► In hydroxyl radical attack on the ring mainly hydroxylated products form ► The hydrated electron attacks the carboxyl group. ► Oxidative conditions are more effective in ibuprofen decomposition than reductive. ► Ecotoxicity of ibuprofen solution first increases then decreases with irradiation

  1. Anaerobic Dehalogenation of Hydroxylated Polychlorinated Biphenyls by Desulfitobacterium dehalogenans

    OpenAIRE

    Wiegel, Juergen; Zhang, Xiaoming; Wu, Qingzhong

    1999-01-01

    Ten years after reports on the existence of anaerobic dehalogenation of polychlorinated biphenyls (PCBs) in sediment slurries, we report here on the rapid reductive dehalogenation of para-hydroxylated PCBs (HO-PCBs), the excreted main metabolites of PCB in mammals, which can exhibit estrogenic and antiestrogenic activities in humans. The anaerobic bacterium Desulfitobacterium dehalogenans completely dehalogenates all flanking chlorines (chlorines in ortho position to the para-hydroxyl group) ...

  2. Report of the working group on single-particle nonlinear dynamics

    International Nuclear Information System (INIS)

    Bazzani, A.; Bongini, L.; Corbett, J.; Dome, G.; Fedorova, A.; Freguglia, P.; Ng, K.; Ohmi, K.; Owen, H.; Papaphilippou, Y.; Robin, D.; Safranek, J.; Scandale, W.; Terebilo, A.; Turchetti, G.; Todesco, E.; Warnock, R.; Zeitlin, M.

    1999-01-01

    The Working Group on single-particle nonlinear dynamics has developed a set of tools to study nonlinear dynamics in a particle accelerator. The design of rings with large dynamic apertures is still far from automatic. The Working Group has concluded that nonlinear single-particle dynamics limits the performance of accelerators. (AIP) copyright 1999 American Institute of Physics

  3. 21 CFR 172.814 - Hydroxylated lecithin.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Hydroxylated lecithin. 172.814 Section 172.814 Food... Multipurpose Additives § 172.814 Hydroxylated lecithin. The food additive hydroxylated lecithin may be safely... obtained by the treatment of lecithin in one of the following ways, under controlled conditions whereby the...

  4. Diffusion of hydroxyl ions from calcium hydroxide and Aloe vera pastes.

    Science.gov (United States)

    Batista, Victor Eduardo de Souza; Olian, Douglas Dáquila; Mori, Graziela Garrido

    2014-01-01

    This study evaluated the diffusion through the dentinal tubules of hydroxyl ions from different calcium hydroxide (CH) pastes containing Aloe vera. Sixty single-rooted bovine teeth were used. The tooth crowns were removed, the root canals were instrumented and the specimens were assigned to 4 groups (n=15) according to the intracanal medication: Group CH/S - CH powder and saline paste; Group CH/P - CH powder and propylene glycol paste; Group CH/A - calcium hydroxide powder and Aloe vera gel paste; Group CH/A/P - CH powder, Aloe vera powder and propylene glycol paste. After placement of the root canal dressings, the teeth were sealed coronally and apically with a two-step epoxy adhesive. The teeth were placed in identified flasks containing deionized water and stored in an oven with 100% humidity at 37 °C. After 3 h, 24 h, 72 h, 7 days, 15 days and 30 days, the deionized water in the flasks was collected and its pH was measured by a pH meter. The obtained data were subjected to statistical analysis at a significance level of 5%. The results demonstrated that all pastes provided diffusion of hydroxyl ions through the dentinal tubules. The combination of Aloe vera and CH (group CH/A) provided a constant release of calcium ions. Group CH/A/P showed the highest pH at 24 and 72 h. In conclusion, the experimental pastes containing Aloe vera were able to enable the diffusion of hydroxyl ions through the dentinal tubules.

  5. Prolyl hydroxylation in elastin is not random.

    Science.gov (United States)

    Schmelzer, Christian E H; Nagel, Marcus B M; Dziomba, Szymon; Merkher, Yulia; Sivan, Sarit S; Heinz, Andrea

    2016-10-01

    This study aimed to investigate the prolyl and lysine hydroxylation in elastin from different species and tissues. Enzymatic digests of elastin samples from human, cattle, pig and chicken were analyzed using mass spectrometry and bioinformatics tools. It was confirmed at the protein level that elastin does not contain hydroxylated lysine residues regardless of the species. In contrast, prolyl hydroxylation sites were identified in all elastin samples. Moreover, the analysis of the residues adjacent to prolines allowed the determination of the substrate site preferences of prolyl 4-hydroxylase. It was found that elastins from all analyzed species contain hydroxyproline and that at least 20%-24% of all proline residues were partially hydroxylated. Determination of the hydroxylation degrees of specific proline residues revealed that prolyl hydroxylation depends on both the species and the tissue, however, is independent of age. The fact that the highest hydroxylation degrees of proline residues were found for elastin from the intervertebral disc and knowledge of elastin arrangement in this tissue suggest that hydroxylation plays a biomechanical role. Interestingly, a proline-rich domain of tropoelastin (domain 24), which contains several repeats of bioactive motifs, does not show any hydroxyproline residues in the mammals studied. The results show that prolyl hydroxylation is not a coincidental feature and may contribute to the adaptation of the properties of elastin to meet the functional requirements of different tissues. The study for the first time shows that prolyl hydroxylation is highly regulated in elastin. Copyright © 2016 Elsevier B.V. All rights reserved.

  6. Impact of Group Support on Adjustment to Divorce by Single, Custodial Fathers.

    Science.gov (United States)

    Tedder, Sandra L.; And Others

    1984-01-01

    Discusses the effects of a support group for single, custodial fathers (N=36) on measures of divorce adjustment, loneliness, and self-concept. Results indicated that men who attended the group meetings made more positive changes than those who did not attend and indicated a desire for support, sharing, and discussion. (JAC)

  7. Characterization of the Ornithine Hydroxylation Step in Albachelin Biosynthesis

    Directory of Open Access Journals (Sweden)

    Kendra Bufkin

    2017-10-01

    Full Text Available N-Hydroxylating monooxygenases (NMOs are involved in siderophore biosynthesis. Siderophores are high affinity iron chelators composed of catechol and hydroxamate functional groups that are synthesized and secreted by microorganisms and plants. Recently, a new siderophore named albachelin was isolated from a culture of Amycolatopsis alba growing under iron-limiting conditions. This work focuses on the expression, purification, and characterization of the NMO, abachelin monooxygenase (AMO from A. alba. This enzyme was purified and characterized in its holo (FAD-bound and apo (FAD-free forms. The apo-AMO could be reconstituted by addition of free FAD. The two forms of AMO hydroxylate ornithine, while lysine increases oxidase activity but is not hydroxylated and display low affinity for NADPH.

  8. Prolyl hydroxylation in elastin is not random

    DEFF Research Database (Denmark)

    Schmelzer, Christian E H; Nagel, Marcus B M; Dziomba, Szymon

    2016-01-01

    BACKGROUND: This study aimed to investigate the prolyl and lysine hydroxylation in elastin from different species and tissues. METHODS: Enzymatic digests of elastin samples from human, cattle, pig and chicken were analyzed using mass spectrometry and bioinformatics tools. RESULTS: It was confirmed...... at the protein level that elastin does not contain hydroxylated lysine residues regardless of the species. In contrast, prolyl hydroxylation sites were identified in all elastin samples. Moreover, the analysis of the residues adjacent to prolines allowed the determination of the substrate site preferences...... of prolyl 4-hydroxylase. It was found that elastins from all analyzed species contain hydroxyproline and that at least 20%-24% of all proline residues were partially hydroxylated. Determination of the hydroxylation degrees of specific proline residues revealed that prolyl hydroxylation depends on both...

  9. A note on resource allocation scheduling with group technology and learning effects on a single machine

    Science.gov (United States)

    Lu, Yuan-Yuan; Wang, Ji-Bo; Ji, Ping; He, Hongyu

    2017-09-01

    In this article, single-machine group scheduling with learning effects and convex resource allocation is studied. The goal is to find the optimal job schedule, the optimal group schedule, and resource allocations of jobs and groups. For the problem of minimizing the makespan subject to limited resource availability, it is proved that the problem can be solved in polynomial time under the condition that the setup times of groups are independent. For the general setup times of groups, a heuristic algorithm and a branch-and-bound algorithm are proposed, respectively. Computational experiments show that the performance of the heuristic algorithm is fairly accurate in obtaining near-optimal solutions.

  10. Mechanism of aromatic hydroxylation of lidocaine at a Pt electrode under acidic conditions

    NARCIS (Netherlands)

    Gul, Turan; Bischoff, Rainer; Permentier, Hjalmar P.

    2017-01-01

    Aromatic hydroxylation reactions, which are mainly catalyzed by cytochrome P450 (CYP) enzymes in vivo, are some of the most important reactions of Phase I metabolism, because insertion of a hydroxyl group into a lipophilic drug compound increases its hydrophilicity and prepares it for subsequent

  11. Discrimination of communication vocalizations by single neurons and groups of neurons in the auditory midbrain.

    Science.gov (United States)

    Schneider, David M; Woolley, Sarah M N

    2010-06-01

    Many social animals including songbirds use communication vocalizations for individual recognition. The perception of vocalizations depends on the encoding of complex sounds by neurons in the ascending auditory system, each of which is tuned to a particular subset of acoustic features. Here, we examined how well the responses of single auditory neurons could be used to discriminate among bird songs and we compared discriminability to spectrotemporal tuning. We then used biologically realistic models of pooled neural responses to test whether the responses of groups of neurons discriminated among songs better than the responses of single neurons and whether discrimination by groups of neurons was related to spectrotemporal tuning and trial-to-trial response variability. The responses of single auditory midbrain neurons could be used to discriminate among vocalizations with a wide range of abilities, ranging from chance to 100%. The ability to discriminate among songs using single neuron responses was not correlated with spectrotemporal tuning. Pooling the responses of pairs of neurons generally led to better discrimination than the average of the two inputs and the most discriminating input. Pooling the responses of three to five single neurons continued to improve neural discrimination. The increase in discriminability was largest for groups of neurons with similar spectrotemporal tuning. Further, we found that groups of neurons with correlated spike trains achieved the largest gains in discriminability. We simulated neurons with varying levels of temporal precision and measured the discriminability of responses from single simulated neurons and groups of simulated neurons. Simulated neurons with biologically observed levels of temporal precision benefited more from pooling correlated inputs than did neurons with highly precise or imprecise spike trains. These findings suggest that pooling correlated neural responses with the levels of precision observed in the

  12. Quantification of hydroxyl radical produced during phacoemulsification.

    Science.gov (United States)

    Gardner, Jonathan M; Aust, Steven D

    2009-12-01

    To quantitate hydroxyl radicals produced during phacoemulsification with various irrigating solutions and conditions used in cataract surgery. Chemistry and Biochemistry Department, Utah State University, Logan, Utah, USA. All experiments were performed using an Infiniti Vision System phacoemulsifier with irrigation and aspiration. Hydroxyl radicals were quantitated using electron spin resonance spectroscopy and a spectrophotometric assay for malondialdehyde, which is formed by the oxidation of deoxyribose by the hydroxyl radical. Hydroxyl radical production increased during longitudinal-stroking phacoemulsification as power levels were increased in a nonlinear, nonexponential fashion. The detection of hydroxyl radical was reduced in irrigating solutions containing organic molecules (eg, citrate, acetate, glutathione, dextrose) and further reduced in Navstel, an irrigating solution containing a viscosity-modifying agent, hydroxypropyl methylcellulose. Hydroxyl radicals produced in settings representative of those used in phacoemulsification cataract surgery were quantitated using the deoxyribose method. Hydroxyl radical production was dependent on the level of ultrasound power applied and the irrigating solution used. Oxidative stress on the eye during phacoemulsification may be minimized by using irrigating solutions that contain organic molecules, including the viscosity-modifying agent hydroxypropyl methylcellulose, that can compete for reaction with hydroxyl radicals.

  13. A single mothers' group for mothers of children attending an outpatient psychiatric clinic: preliminary results.

    Science.gov (United States)

    McNamee, J E; Lipman, E L; Hicks, F

    1995-09-01

    To provide a preliminary report of data from 2 support groups for single mothers, all of whom were mothers of children attending a child outpatient psychiatric clinic. The groups' 2 purposes were: 1. to assess the feasibility of adding structured evaluation to a common clinical intervention; 2. to improve single mothers' parenting skills through raised levels of self-esteem, increased capacity for family functioning and reduced levels of depression. Three structured evaluation instruments were used to measure the domains of self-esteem, family functioning and depression. These instruments were given to both groups of women on 3 occasions: 1. before the group; 2. after the group; 3. at a follow-up session 4 months after group termination. Open-ended questions were also asked at group termination. The questionnaire response rate was 100%; overall response rate for the 3 open-ended questions was 89%. Comparisons of pre-group and post-group scores showed that there was a significant increase in self-esteem (p parenting skills. Methodologic concerns and future directions are discussed.

  14. Hydroxyl-dependent Evolution of Oxygen Vacancies Enables the Regeneration of BiOCl photocatalyst

    KAUST Repository

    Wu, Sujuan

    2017-05-02

    Photoinduced oxygen vacancies (OVs) are widely investigated as a vital point defect in wide-band-gap semiconductors. Still, the formation mechanism of OVs remains unclear in various materials. To elucidate the formation mechanism of photoinduced OVs in bismuth oxychloride (BiOCl), we synthesized two surface hydroxyl discrete samples in light of the discovery of the significant variance of hydroxyl groups before and after UV light exposure. It is noted that OVs can be obtained easily after UV light irradiation in the sample with surface hydroxyl groups, while variable changes were observed in samples without surface hydroxyls. Density functional theory (DFT) calculations reveal that the binding energy of Bi-O is drastically influenced by surficial hydroxyl groups, which is intensely correlated to the formation of photoinduced OVs. Moreover, DFT calculations reveal that the adsorbed water molecules are energetically favored to dissociate into separate hydroxyl groups at the OV sites via proton transfer to a neighboring bridging oxygen atom, forming two bridging hydroxyl groups per initial oxygen vacancy. This result is consistent with the experimental observation that the disappearance of photoinduced OVs and the recovery of hydroxyl groups on the surface of BiOCl after exposed to a H2O(g)-rich atmosphere, and finally enables the regeneration of BiOCl photocatalyst. Here, we introduce new insights that the evolution of photoinduced OVs is dependent on surface hydroxyl groups, which will lead to the regeneration of active sites in semiconductors. This work is useful for controllable designs of defective semiconductors for applications in photocatalysis and photovoltaics.

  15. Study of hydroxylation of benzene and toluene using a micro-DBD plasma reactor

    International Nuclear Information System (INIS)

    Sekiguchi, H; Ando, M; Kojima, H

    2005-01-01

    The hydroxylation behaviour of benzene and toluene were studied using a micro-plasma reactor, where an atmospheric non-thermal plasma was generated by a dielectric barrier discharge (DBD). The results indicated that oxidation products primarily consisted of phenol and C 4 -compounds for benzene hydroxylation, whereas cresol, benzaldehyde, benzylalcohol and C 4 -compounds were detected for toluene hydroxylation. By taking into consideration the reaction mechanism in the plasma reactor, these products were classified into (1) oxidation of the aromatic ring and functional group on the ring and (2) cleavage of the aromatic ring or dissociation of the functional group on the ring

  16. Differential effects of collagen prolyl 3-hydroxylation on skeletal tissues.

    Directory of Open Access Journals (Sweden)

    Erica P Homan

    2014-01-01

    Full Text Available Mutations in the genes encoding cartilage associated protein (CRTAP and prolyl 3-hydroxylase 1 (P3H1 encoded by LEPRE1 were the first identified causes of recessive Osteogenesis Imperfecta (OI. These proteins, together with cyclophilin B (encoded by PPIB, form a complex that 3-hydroxylates a single proline residue on the α1(I chain (Pro986 and has cis/trans isomerase (PPIase activity essential for proper collagen folding. Recent data suggest that prolyl 3-hydroxylation of Pro986 is not required for the structural stability of collagen; however, the absence of this post-translational modification may disrupt protein-protein interactions integral for proper collagen folding and lead to collagen over-modification. P3H1 and CRTAP stabilize each other and absence of one results in degradation of the other. Hence, hypomorphic or loss of function mutations of either gene cause loss of the whole complex and its associated functions. The relative contribution of losing this complex's 3-hydroxylation versus PPIase and collagen chaperone activities to the phenotype of recessive OI is unknown. To distinguish between these functions, we generated knock-in mice carrying a single amino acid substitution in the catalytic site of P3h1 (Lepre1(H662A . This substitution abolished P3h1 activity but retained ability to form a complex with Crtap and thus the collagen chaperone function. Knock-in mice showed absence of prolyl 3-hydroxylation at Pro986 of the α1(I and α1(II collagen chains but no significant over-modification at other collagen residues. They were normal in appearance, had no growth defects and normal cartilage growth plate histology but showed decreased trabecular bone mass. This new mouse model recapitulates elements of the bone phenotype of OI but not the cartilage and growth phenotypes caused by loss of the prolyl 3-hydroxylation complex. Our observations suggest differential tissue consequences due to selective inactivation of P3H1 hydroxylase

  17. The Influence of Single - Sex Tourist Groups on Creating the Identity of Their Members - Case Study

    OpenAIRE

    Švorcová, Tereza

    2016-01-01

    This MA thesis deals with the influence of single-sex tourist groups on creating the identity of their members. The aim is to discover the effect of membership in such a non-coeducational tourist clubs on children, and also how this leisure activity affects children's identity and what impact it has on their development.
 The theoretical part discusses socializing, social environment, gender, gender socialization and gender stereotypes. Furthermore, it also deals with the influence of peers a...

  18. Trimeric Hydrogen Bond in Geometrically Frustrated Hydroxyl Cobalt Halogenides

    International Nuclear Information System (INIS)

    Xiao-Dong, Liu; Masato, Hagihala; Xu-Guang, Zheng; Dong-Dong, Meng; Wan-Jun, Tao; Sen-Lin, Zhang; Qi-Xin, Guo

    2011-01-01

    The mid-infrared absorption spectra of geometrically frustrated hydroxyl cobalt halogenides Co 2 (OH) 3 Cl and Co 2 (OH) 3 Br are measured by FTIR spectrometers, and the stretching vibrational modes of hydroxyl groups are found to be 3549cm −1 and 3524cm −1 respectively. Through finding their true terminal O-H group stretching vibration frequencies, we obtain 107cm −1 and 99cm −1 red shift caused by the corresponding O-H···Cl and O-H···Br hydrogen bonds. Rarely reported trimeric hydrogen bonds (Co 3 ≡O-H) 3 ···Cl/Br are pointed out to demonstrate the relative weakness of this kind of hydrogen bond which may have a critical effect on the lattice symmetry and magnetic structures. (condensed matter: electronic structure, electrical, magnetic, and optical properties)

  19. Functionalization of hydroxyl terminated polybutadiene with ...

    Indian Academy of Sciences (India)

    CBDT), has been covalently attached at the terminal carbon atoms of the hydroxyl terminated polybutadiene (HTPB) backbone. The modification of HTPB backbone by CBDT molecule does not affect the unique physico-chemical properties such ...

  20. Using machine learning to identify structural breaks in single-group interrupted time series designs.

    Science.gov (United States)

    Linden, Ariel; Yarnold, Paul R

    2016-12-01

    Single-group interrupted time series analysis (ITSA) is a popular evaluation methodology in which a single unit of observation is being studied, the outcome variable is serially ordered as a time series and the intervention is expected to 'interrupt' the level and/or trend of the time series, subsequent to its introduction. Given that the internal validity of the design rests on the premise that the interruption in the time series is associated with the introduction of the treatment, treatment effects may seem less plausible if a parallel trend already exists in the time series prior to the actual intervention. Thus, sensitivity analyses should focus on detecting structural breaks in the time series before the intervention. In this paper, we introduce a machine-learning algorithm called optimal discriminant analysis (ODA) as an approach to determine if structural breaks can be identified in years prior to the initiation of the intervention, using data from California's 1988 voter-initiated Proposition 99 to reduce smoking rates. The ODA analysis indicates that numerous structural breaks occurred prior to the actual initiation of Proposition 99 in 1989, including perfect structural breaks in 1983 and 1985, thereby casting doubt on the validity of treatment effects estimated for the actual intervention when using a single-group ITSA design. Given the widespread use of ITSA for evaluating observational data and the increasing use of machine-learning techniques in traditional research, we recommend that structural break sensitivity analysis is routinely incorporated in all research using the single-group ITSA design. © 2016 John Wiley & Sons, Ltd.

  1. Electrical properties and mechanical stability of anchoring groups for single-molecule electronics

    Directory of Open Access Journals (Sweden)

    Riccardo Frisenda

    2015-07-01

    Full Text Available We report on an experimental investigation of transport through single molecules, trapped between two gold nano-electrodes fabricated with the mechanically controlled break junction (MCBJ technique. The four molecules studied share the same core structure, namely oligo(phenylene ethynylene (OPE3, while having different aurophilic anchoring groups: thiol (SAc, methyl sulfide (SMe, pyridyl (Py and amine (NH2. The focus of this paper is on the combined characterization of the electrical and mechanical properties determined by the anchoring groups. From conductance histograms we find that thiol anchored molecules provide the highest conductance; a single-level model fit to current–voltage characteristics suggests that SAc groups exhibit a higher electronic coupling to the electrodes, together with better level alignment than the other three groups. An analysis of the mechanical stability, recording the lifetime in a self-breaking method, shows that Py and SAc yield the most stable junctions while SMe form short-lived junctions. Density functional theory combined with non-equlibrium Green’s function calculations help in elucidating the experimental findings.

  2. The electrochemical signature of functionalized single-walled carbon nanotubes bearing electroactive groups

    International Nuclear Information System (INIS)

    Le Floch, Fabien; Thuaire, Aurelie; Simonato, Jean-Pierre; Bidan, Gerard

    2009-01-01

    We report the modification and characterization of single-walled carbon nanotubes (SWCNTs) in view of molecular sensing applications. We found that ultrasonicated SWCNTs present sticking properties that make them adhere on electrode surfaces. This allows excellent characterization of SWCNTs by cyclic voltammetry (CV) before and after chemical functionalization with diazonium salts bearing electroactive groups. Bare SWCNTs presented distinct invariant shapes in CV, used as control curves, in comparison with functionalized SWCNTs for which specific signatures corresponding to the presence of grafted molecules were identified. According to the electronic substituents in the para position of the diazonium salts, divergent behaviours were observed for the grafting reactions. Diazonium salts having electrowithdrawing groups could be grafted without electrochemical induction whereas those bearing electron donating groups required a cathodic potential to generate the formation of the radical species.

  3. The electrochemical signature of functionalized single-walled carbon nanotubes bearing electroactive groups

    Energy Technology Data Exchange (ETDEWEB)

    Le Floch, Fabien; Thuaire, Aurelie; Simonato, Jean-Pierre [LITEN/DTNM/LCRE, CEA-Grenoble 17 rue des Martyrs, 38054 Grenoble cedex 9 (France); Bidan, Gerard [INAC/DIR, CEA-Grenoble 17 rue des Martyrs, 38054 Grenoble cedex 9 (France)], E-mail: jean-pierre.simonato@cea.fr

    2009-04-08

    We report the modification and characterization of single-walled carbon nanotubes (SWCNTs) in view of molecular sensing applications. We found that ultrasonicated SWCNTs present sticking properties that make them adhere on electrode surfaces. This allows excellent characterization of SWCNTs by cyclic voltammetry (CV) before and after chemical functionalization with diazonium salts bearing electroactive groups. Bare SWCNTs presented distinct invariant shapes in CV, used as control curves, in comparison with functionalized SWCNTs for which specific signatures corresponding to the presence of grafted molecules were identified. According to the electronic substituents in the para position of the diazonium salts, divergent behaviours were observed for the grafting reactions. Diazonium salts having electrowithdrawing groups could be grafted without electrochemical induction whereas those bearing electron donating groups required a cathodic potential to generate the formation of the radical species.

  4. Impact of Anchoring Groups on Ballistic Transport: Single Molecule vs Monolayer Junctions

    Science.gov (United States)

    2015-01-01

    Tuning the transport properties of molecular junctions by chemically modifying the molecular structure is one of the key challenges for advancing the field of molecular electronics. In the present contribution, we investigate current–voltage characteristics of differently linked metal–molecule–metal systems that comprise either a single molecule or a molecular assembly. This is achieved by employing density functional theory in conjunction with a Green’s function approach. We show that the conductance of a molecular system with a specific anchoring group is fundamentally different depending on whether a single molecule or a continuous monolayer forms the junction. This is a consequence of collective electrostatic effects that arise from dipolar elements contained in the monolayer and from interfacial charge rearrangements. As a consequence of these collective effects, the “ideal” choice for an anchoring group is clearly different for monolayer and single molecule devices. A particularly striking effect is observed for pyridine-docked systems. These are subject to Fermi-level pinning at high molecular packing densities, causing an abrupt increase of the junction current already at small voltages. PMID:26401191

  5. DFT Study of Binding and Electron Transfer from a Metal-Free Dye with Carboxyl, Hydroxyl, and Sulfonic Anchors to a Titanium Dioxide Nanocluster

    Directory of Open Access Journals (Sweden)

    Corneliu I. Oprea

    2013-01-01

    Full Text Available We report results of density functional theory (DFT calculations of a metal-free dye, 5-(4-sulfophenylazosalicylic acid disodium salt, known as Mordant Yellow 10 (MY-10, used as sensitizer for TiO2 dye-sensitized solar cells (DSSCs. Given the need to better understand the behavior of the dyes adsorbed on the TiO2 nanoparticle, we studied various single and double deprotonated forms of the dye bound to a TiO2 cluster, taking advantage of the presence of the carboxyl, hydroxyl, and sulfonic groups as possible anchors. We discuss various binding configurations to the TiO2 substrate and the charge transfer from the pigment to the oxide by means of DFT calculations. In agreement with other reports, we find that the carboxyl group tends to bind in bidentate bridging configurations. The salicylate uses both the carboxyl and hydroxyl substituent groups for either a tridentate binding to adjacent Ti(IV ions or a bidentate Ti-O binding together with an O-H-O binding, due to the rotation of the carboxyl group out of the plane of the dye. The sulfonic group prefers a tridentate binding. We analyze the propensity for electron transfer of the various dyes and find that for MY-10, as a function of the anchor group, the DSSC performance decreases in the order hydroxyl + carboxyl > carboxyl > sulfonate.

  6. Single-layer group IV-V and group V-IV-III-VI semiconductors: Structural stability, electronic structures, optical properties, and photocatalysis

    Science.gov (United States)

    Lin, Jia-He; Zhang, Hong; Cheng, Xin-Lu; Miyamoto, Yoshiyuki

    2017-07-01

    Recently, single-layer group III monochalcogenides have attracted both theoretical and experimental interest at their potential applications in photonic devices, electronic devices, and solar energy conversion. Excited by this, we theoretically design two kinds of highly stable single-layer group IV-V (IV =Si ,Ge , and Sn; V =N and P) and group V-IV-III-VI (IV =Si ,Ge , and Sn; V =N and P; III =Al ,Ga , and In; VI =O and S) compounds with the same structures with single-layer group III monochalcogenides via first-principles simulations. By using accurate hybrid functional and quasiparticle methods, we show the single-layer group IV-V and group V-IV-III-VI are indirect bandgap semiconductors with their bandgaps and band edge positions conforming to the criteria of photocatalysts for water splitting. By applying a biaxial strain on single-layer group IV-V, single-layer group IV nitrides show a potential on mechanical sensors due to their bandgaps showing an almost linear response for strain. Furthermore, our calculations show that both single-layer group IV-V and group V-IV-III-VI have absorption from the visible light region to far-ultraviolet region, especially for single-layer SiN-AlO and SnN-InO, which have strong absorption in the visible light region, resulting in excellent potential for solar energy conversion and visible light photocatalytic water splitting. Our research provides valuable insight for finding more potential functional two-dimensional semiconductors applied in optoelectronics, solar energy conversion, and photocatalytic water splitting.

  7. Comprehensive Wavelengths, Energy Levels, and Hyperfine Structure Parameters of Singly-Ionized Iron-Group Elements

    Science.gov (United States)

    Nave, Gillian

    We propose to measure wavelengths, energy levels, and hyperfine structure parameters of Ni II, Mn II, Sc II and other singly-ionized iron-group elements, covering the wavelength range 80 nm to 5500 nm. We shall use archival data from spectrometers at NIST and Kitt Peak National Observatory for spectra above 140 nm. Additional experimental observations will be taken if needed using Fourier transform spectrometers at NIST. Spectra will be taken using our normal incidence grating spectrograph to provide better sensitivity than the FT spectra and to extend the wavelength range down to 80 nm. We aim to produce a comprehensive description of the spectra of all singly-ionized iron- group elements. The wavelength uncertainty of the strong lines will be better than 1 part in 10^7. For most singly-ionized iron-group elements available laboratory data have uncertainties an order of magnitude larger than astronomical observations over wide spectra ranges. Some of these laboratory measurements date back to the 1960's. Since then, Fourier transform spectroscopy has made significant progress in improving the accuracy and quantity of data in the UV-vis-IR region, but high quality Fourier transform spectra are still needed for Mn II, Ni II and Sc II. Fourier transform spectroscopy has low sensitivity in the VUV region and is limited to wavelengths above 140 nm. Spectra measured with high-resolution grating spectrographs are needed in this region in order to obtain laboratory data of comparable quality to the STIS and COS spectrographs on the Hubble Space Telescope. Currently, such data exist only for Fe II and Cr II. Lines of Sc II, V II, and Mn II show hyperfine structure, but hyperfine structure parameters have been measured for relatively few lines of these elements. Significant errors can occur if hyperfine structure is neglected when abundances are determined from stellar spectra. Measurements of hyperfine structure parameters will be made using Fourier transform spectroscopy

  8. Controlling formation of single-molecule junctions by electrochemical reduction of diazonium terminal groups.

    Science.gov (United States)

    Hines, Thomas; Díez-Pérez, Ismael; Nakamura, Hisao; Shimazaki, Tomomi; Asai, Yoshihiro; Tao, Nongjian

    2013-03-06

    We report controlling the formation of single-molecule junctions by means of electrochemically reducing two axialdiazonium terminal groups on a molecule, thereby producing direct Au-C covalent bonds in situ between the molecule and gold electrodes. We report a yield enhancement in molecular junction formation as the electrochemical potential of both junction electrodes approach the reduction potential of the diazonium terminal groups. Step length analysis shows that the molecular junction is significantly more stable, and can be pulled over a longer distance than a comparable junction created with amine anchoring bonds. The stability of the junction is explained by the calculated lower binding energy associated with the direct Au-C bond compared with the Au-N bond.

  9. SINGLE-CASE INVESTIGATION OF AN EMOTION-FOCUSED THERAPY GROUP FOR ANXIETY AND DEPRESSION

    Directory of Open Access Journals (Sweden)

    Adèle Lafrance Robinson

    2012-11-01

    Full Text Available Emotion-focused therapy (EFT is an evidence-based treatment for depression and trauma and has shown promise for other presentations including anxiety. Minimal research exists investigating the outcomes of emotion-focused therapy in a group setting. The current research presents a mixed-method single-case study of one client’s experiences and outcomes following a nine-week EFT group for depression and anxiety. Weekly measures of session-feelings evaluations were collected. Follow-up measures, including a qualitative interview, were administered one year post-treatment. Pre-, post-, and follow-up measures assessed depression, anxiety, and emotional regulation. Results showed clinically significant improvements in anxiety, depression, and emotional regulation over time. Indirect and direct evidence of client change were detected. Five super-ordinate themes with sub-themes emerged from the qualitative analysis.

  10. A discrete single server queue with Markovian arrivals and phase type group services

    Directory of Open Access Journals (Sweden)

    Attahiru Sule Alfa

    1995-01-01

    Full Text Available We consider a single-server discrete queueing system in which arrivals occur according to a Markovian arrival process. Service is provided in groups of size no more than M customers. The service times are assumed to follow a discrete phase type distribution, whose representation may depend on the group size. Under a probabilistic service rule, which depends on the number of customers waiting in the queue, this system is studied as a Markov process. This type of queueing system is encountered in the operations of an automatic storage retrieval system. The steady-state probability vector is shown to be of (modified matrix-geometric type. Efficient algorithmic procedures for the computation of the rate matrix, steady-state probability vector, and some important system performance measures are developed. The steady-state waiting time distribution is derived explicitly. Some numerical examples are presented.

  11. Exploring the Relevance of Single-Gender Group Formation: What We Learn from a Massive Open Online Course (MOOC)

    Science.gov (United States)

    Bayeck, Rebecca Yvonne; Hristova, Adelina; Jablokow, Kathryn W.; Bonafini, Fernanda

    2018-01-01

    This paper reports the results of an exploratory study on participants' perception of the importance of single-gender grouping in a massive open online course (MOOC) delivered through the Coursera platform. Findings reveal that female and male learners' perception of single-gender grouping differs. Female students more than males indicated less…

  12. Anchor-dependent lipofection with non-glycerol based cytofectins containing single 2-hydroxyethyl head groups.

    Science.gov (United States)

    Venkata Srilakshmi, Gollapudi; Sen, Joyeeta; Chaudhuri, Arabinda; Ramadas, Yerramsetti; Madhusudhana Rao, Nalam

    2002-02-15

    Detailed structure-activity investigations aimed at probing the anchor chain length dependency for glycerol-based lipofectins have been reported previously. Herein, we report on the first detailed investigation on the anchor-dependent transfection biology of non-glycerol based simple monocationic cytofectins containing single 2-hydroxyethyl head group functionality using 11 new structural analogs of our previously published first generation of non-glycerol based transfection lipids (lipids 1-11). The C-14 and C-16 analogs of DOMHAC (lipids 4 and 5, respectively) were found to be remarkably efficient in transfecting COS-1 cells. In addition, the present anchor-dependency investigation also revealed that the C-14 analog of DOHEMAB (lipid 10) is significantly efficient in transfecting both COS-1 and NIH3T3 cells. Our results also indicate that too strong lipid-DNA interactions might result in weaker transfection for non-glycerol based cationic lipids. In summary, the anchor-dependence investigations presented here convincingly demonstrate that non-glycerol based cationic lipids containing a single hydroxyethyl head group and hydrophobic C-14 or C-16 anchors are promising non-toxic cationic transfection lipids for future use in liposomal gene delivery.

  13. A new method for explicit modelling of single failure event within different common cause failure groups

    International Nuclear Information System (INIS)

    Kančev, Duško; Čepin, Marko

    2012-01-01

    Redundancy and diversity are the main principles of the safety systems in the nuclear industry. Implementation of safety components redundancy has been acknowledged as an effective approach for assuring high levels of system reliability. The existence of redundant components, identical in most of the cases, implicates a probability of their simultaneous failure due to a shared cause—a common cause failure. This paper presents a new method for explicit modelling of single component failure event within multiple common cause failure groups simultaneously. The method is based on a modification of the frequently utilised Beta Factor parametric model. The motivation for development of this method lays in the fact that one of the most widespread softwares for fault tree and event tree modelling as part of the probabilistic safety assessment does not comprise the option for simultaneous assignment of single failure event to multiple common cause failure groups. In that sense, the proposed method can be seen as an advantage of the explicit modelling of common cause failures. A standard standby safety system is selected as a case study for application and study of the proposed methodology. The results and insights implicate improved, more transparent and more comprehensive models within probabilistic safety assessment.

  14. Evaluation of single-nucleotide polymorphisms as internal controls in prenatal diagnosis of fetal blood groups.

    Science.gov (United States)

    Doescher, Andrea; Petershofen, Eduard K; Wagner, Franz F; Schunter, Markus; Müller, Thomas H

    2013-02-01

    Determination of fetal blood groups in maternal plasma samples critically depends on adequate amplification of fetal DNA. We evaluated the routine inclusion of 52 single-nucleotide polymorphisms (SNPs) as internal reference in our polymerase chain reaction (PCR) settings to obtain a positive internal control for fetal DNA. DNA from 223 plasma samples of pregnant women was screened for RHD Exons 3, 4, 5, and 7 in a multiplex PCR including 52 SNPs divided into four primer pools. Amplicons were analyzed by single-base extension and the GeneScan method in a genetic analyzer. Results of D screening were compared to standard RHD genotyping of amniotic fluid or real-time PCR of fetal DNA from maternal plasma. The vast majority of all samples (97.8%) demonstrated differences in maternal and fetal SNP patterns when tested with four primer pools. These differences were not observed in less than 2.2% of the samples most probably due to an extraction failure for adequate amounts of fetal DNA. Comparison of the fetal genotypes with independent results did not reveal a single false-negative case among samples (n = 42) with positive internal control and negative fetal RHD typing. Coamplification of 52 SNPs with RHD-specific sequences for fetal blood group determination introduces a valid positive control for the amplification of fetal DNA to avoid false-negative results. This new approach does not require a paternal blood sample. It may also be applicable to other assays for fetal genotyping in maternal blood samples. © 2012 American Association of Blood Banks.

  15. Using forecast modelling to evaluate treatment effects in single-group interrupted time series analysis.

    Science.gov (United States)

    Linden, Ariel

    2018-05-11

    Interrupted time series analysis (ITSA) is an evaluation methodology in which a single treatment unit's outcome is studied serially over time and the intervention is expected to "interrupt" the level and/or trend of that outcome. ITSA is commonly evaluated using methods which may produce biased results if model assumptions are violated. In this paper, treatment effects are alternatively assessed by using forecasting methods to closely fit the preintervention observations and then forecast the post-intervention trend. A treatment effect may be inferred if the actual post-intervention observations diverge from the forecasts by some specified amount. The forecasting approach is demonstrated using the effect of California's Proposition 99 for reducing cigarette sales. Three forecast models are fit to the preintervention series-linear regression (REG), Holt-Winters (HW) non-seasonal smoothing, and autoregressive moving average (ARIMA)-and forecasts are generated into the post-intervention period. The actual observations are then compared with the forecasts to assess intervention effects. The preintervention data were fit best by HW, followed closely by ARIMA. REG fit the data poorly. The actual post-intervention observations were above the forecasts in HW and ARIMA, suggesting no intervention effect, but below the forecasts in the REG (suggesting a treatment effect), thereby raising doubts about any definitive conclusion of a treatment effect. In a single-group ITSA, treatment effects are likely to be biased if the model is misspecified. Therefore, evaluators should consider using forecast models to accurately fit the preintervention data and generate plausible counterfactual forecasts, thereby improving causal inference of treatment effects in single-group ITSA studies. © 2018 John Wiley & Sons, Ltd.

  16. NO on {CoO(111) }/{Co(0001) }: hydroxyl assisted adsorption

    Science.gov (United States)

    Hassel, M.; Freund, H.-J.

    1995-02-01

    We have investigated the structure of epitaxially grown CoO(111) on Co(0001) and the adsorption of NO on this surface using electron spectroscopic methods. The procedure of oxidation of a cobalt surface to get a single-crystal oxide surface has been chosen for two reasons: first, charging of the sample can be avoided when preparing oxide surfaces of only 20-30 Å thickness. Second, the (111) surface of the ionic rocksalt structure is thermodynamically unstable and thus not otherwise easily accessible for surface studies. We show that the (111) surface is terminated by hydroxyl groups which we think stabilize the surface in the same way as the NiO(111) surface is stabilized [F. Rohr et al., Surf. Sci. 315 (1994) L297; D. Cappus et al., Chem. Phys. 177 (1993) 533], and that the adsorption of NO is affected by the presence of OH.

  17. Structure, electronic properties, and aggregation behavior of hydroxylated carbon nanotubes

    Energy Technology Data Exchange (ETDEWEB)

    López-Oyama, A. B.; Silva-Molina, R. A.; Ruíz-García, J.; Guirado-López, R. A., E-mail: guirado@ifisica.uaslp.mx [Instituto de Física “Manuel Sandoval Vallarta,” Universidad Autónoma de San Luis Potosí, Álvaro Obregón 64, 78000 San Luis Potosí, San Luis Potosí (Mexico); Gámez-Corrales, R. [Departamento de Física, Universidad de Sonora, Apartado Postal 5-088, 83190, Hermosillo, Sonora (Mexico)

    2014-11-07

    We present a combined experimental and theoretical study to analyze the structure, electronic properties, and aggregation behavior of hydroxylated multiwalled carbon nanotubes (OH–MWCNT). Our MWCNTs have average diameters of ∼2 nm, lengths of approximately 100–300 nm, and a hydroxyl surface coverage θ∼0.1. When deposited on the air/water interface the OH–MWCNTs are partially soluble and the floating units interact and link with each other forming extended foam-like carbon networks. Surface pressure-area isotherms of the nanotube films are performed using the Langmuir balance method at different equilibration times. The films are transferred into a mica substrate and atomic force microscopy images show that the foam like structure is preserved and reveals fine details of their microstructure. Density functional theory calculations performed on model hydroxylated carbon nanotubes show that low energy atomic configurations are found when the OH groups form molecular islands on the nanotube's surface. This patchy behavior for the OH species is expected to produce nanotubes having reduced wettabilities, in line with experimental observations. OH doping yields nanotubes having small HOMO–LUMO energy gaps and generates a nanotube → OH direction for the charge transfer leading to the existence of more hole carriers in the structures. Our synthesized OH–MWCNTs might have promising applications.

  18. The hydroxyl species and acid sites on diatomite surface: a combined IR and Raman study

    Science.gov (United States)

    Yuan, P.; Wu, D. Q.; He, H. P.; Lin, Z. Y.

    2004-04-01

    Diffuse reflectance infrared Fourier transform spectroscopy (DRIFT), Raman spectroscopy of adsorbed pyridine molecules (Py-Raman) and in situ Py-IR have been used to investigate the hydroxyl species and acid sites on diatomite surfaces. The Lewis (L) and Brønsted (B) acid sites, and various hydroxyl species, including isolated hydroxyl groups, H-bonded hydroxyl groups and physically adsorbed water, are identified. The L acid sites in diatomite samples are resulted from the clay impurities, and the B acid sites are resulted from some moderate strength H-bonded hydroxyl groups. At room temperature, both of the isolated and H-bonded silanols associate with the physically adsorbed water by hydrogen bond. After calcination treatment, physically adsorbed water will be desorbed from the silanols, and the silanols will condense with the increase of temperature. Generally, the H-bonded silanols condense more easily than the isolated ones. The properties of surface hydroxyl species of diatomaceous silica are more similar to precipitated silica rather than fumed silica.

  19. Are medical treatments for individuals and groups like single-play and multiple-play gambles?

    Directory of Open Access Journals (Sweden)

    Michael L. DeKay

    2006-11-01

    Full Text Available People are often more likely to accept risky monetary gambles with positive expected values when the gambles will be played more than once. We investigated whether this distinction between single-play and multiple-play gambles extends to medical treatments for individual patients and groups of patients. Resident physicians and medical students (extit{n} = 69 and undergraduates (extit{n} = 99 ranked 9 different flu shots and a no-flu-shot option in 1 of 4 combinations of perspective (individual patient vs. group of 1000 patients and uncertainty frame (probability vs. frequency. The rank of the no-flu-shot option (a measure of preference for treatment vs. no treatment was not significantly related to perspective or participant population. The main effect of uncertainty frame and the interaction between perspective and uncertainty frame approached significance (0.1 {extgreater} extit{p} {extgreater} 0.05, with the no-flu-shot option faring particularly poorly (treatment faring particularly well when decisions about many patients were based on frequency information. Undergraduate participants believed that the no-flu-shot option would be less attractive (treatment would be more attractive in decisions about many patients, but these intuitions were inconsistent with the actual ranks. These results and those of other studies suggest that medical treatments for individuals and groups are not analogous to single-play and multiple-play monetary gambles, perhaps because many people are unwilling to aggregate treatment outcomes over patients in the same way that they would compute net gains or losses over monetary gambles.

  20. The stepping behavior analysis of pedestrians from different age groups via a single-file experiment

    Science.gov (United States)

    Cao, Shuchao; Zhang, Jun; Song, Weiguo; Shi, Chang'an; Zhang, Ruifang

    2018-03-01

    The stepping behavior of pedestrians with different age compositions in single-file experiment is investigated in this paper. The relation between step length, step width and stepping time are analyzed by using the step measurement method based on the calculation of curvature of the trajectory. The relations of velocity-step width, velocity-step length and velocity-stepping time for different age groups are discussed and compared with previous studies. Finally effects of pedestrian gender and height on stepping laws and fundamental diagrams are analyzed. The study is helpful for understanding pedestrian dynamics of movement. Meanwhile, it offers experimental data to develop a microscopic model of pedestrian movement by considering stepping behavior.

  1. Magnetic and optical bistability in tetrairon(III) single molecule magnets functionalized with azobenzene groups.

    Science.gov (United States)

    Prasad, Thazhe Kootteri; Poneti, Giordano; Sorace, Lorenzo; Rodriguez-Douton, Maria Jesus; Barra, Anne-Laure; Neugebauer, Petr; Costantino, Luca; Sessoli, Roberta; Cornia, Andrea

    2012-07-21

    Tetrairon(III) complexes known as "ferric stars" have been functionalized with azobenzene groups to investigate the effect of light-induced trans-cis isomerization on single-molecule magnet (SMM) behaviour. According to DC magnetic data and EPR spectroscopy, clusters dispersed in polystyrene (4% w/w) exhibit the same spin (S = 5) and magnetic anisotropy as bulk samples. Ligand photoisomerization, achieved by irradiation at 365 nm, has no detectable influence on static magnetic properties. However, it induces a small but significant acceleration of magnetic relaxation as probed by AC susceptometry. The pristine behaviour can be almost quantitatively recovered by irradiation with white light. Our studies demonstrate that magnetic and optical bistability can be made to coexist in SMM materials, which are of current interest in molecular spintronics.

  2. Single-molecule fluorescence polarization study of conformational change in archaeal group II chaperonin.

    Directory of Open Access Journals (Sweden)

    Ryo Iizuka

    Full Text Available Group II chaperonins found in archaea and in eukaryotic cytosol mediate protein folding without a GroES-like cofactor. The function of the cofactor is substituted by the helical protrusion at the tip of the apical domain, which forms a built-in lid on the central cavity. Although many studies on the change in lid conformation coupled to the binding and hydrolysis of nucleotides have been conducted, the molecular mechanism of lid closure remains poorly understood. Here, we performed a single-molecule polarization modulation to probe the rotation of the helical protrusion of a chaperonin from a hyperthermophilic archaeum, Thermococcus sp. strain KS-1. We detected approximately 35° rotation of the helical protrusion immediately after photorelease of ATP. The result suggests that the conformational change from the open lid to the closed lid state is responsible for the approximately 35° rotation of the helical protrusion.

  3. Single-crystal growth of Group IVB and VB carbides by the floating-zone method

    International Nuclear Information System (INIS)

    Finch, C.B.; Chang, Y.K.; Abraham, M.M.

    1989-02-01

    The floating-zone method for the growth of Group IVB and VB carbides is described and reviewed. We have systematically investigated the technique and confirmed the growth of large single crystals of TiC/sub 0.95/, ZrC/sub 0.93/, ZrC/sub 0.98/, VC/sub 0.80/, NbC/sub 0.95/, TaC/sub 0.89/. Optimal growth conditions were in the 0.5-2.0 cm/h range under 8-12 atm helium. Good crystal growth results were achieved with hot-pressed starting rods of 90-95% density, using a ''double pancake'' induction coil and a 200-kHz/100- kW rf power supply. 36 refs., 5 figs., 3 tabs

  4. Molecular dynamics simulations of single siloxane dendrimers: Molecular structure and intramolecular mobility of terminal groups

    Science.gov (United States)

    Kurbatov, A. O.; Balabaev, N. K.; Mazo, M. A.; Kramarenko, E. Yu.

    2018-01-01

    Molecular dynamics simulations of two types of isolated siloxane dendrimers of various generations (from the 2nd to the 8th) have been performed for temperatures ranging from 150 K to 600 K. The first type of dendrimer molecules has short spacers consisting of a single oxygen atom. In the dendrimers of the second type, spacers are longer and comprised of two oxygen atoms separated by a single silicon atom. A comparative analysis of molecular macroscopic parameters such as the gyration radius and the shape factor as well as atom distributions within dendrimer interior has been performed for varying generation number, temperature, and spacer length. It has been found that the short-spacer dendrimers of the 7th and 8th generations have a stressed central part with elongated bonds and deformed valence angles. Investigation of the time evolution of radial displacements of the terminal Si atoms has shown that a fraction of the Si groups have a reduced mobility. Therefore, rather long time trajectories (of the order of tens of nanoseconds) are required to study dendrimer intramolecular dynamics.

  5. Presence of hydrogen peroxide, a source of hydroxyl radicals, in acid electrolyzed water.

    Directory of Open Access Journals (Sweden)

    Takayuki Mokudai

    Full Text Available BACKGROUND: Acid electrolyzed water (AEW, which is produced through the electrolysis of dilute sodium chloride (NaCl or potassium chloride solution, is used as a disinfectant in various fields because of its potent antimicrobial activity. The hydroxyl radical, an oxygen radical species, is often suggested as a putative active ingredient for AEW antimicrobial activity. METHODOLOGY/PRINCIPAL FINDINGS: The aim of the present study is to detect hydroxyl radicals in AEW. The hydroxyl radicals in AEW prepared under different conditions were determined using an electron spin resonance (ESR technique. A signal from 5,5-dimethyl-1-pyrroline N-oxide (DMPO-OH, an adduct of DMPO and the hydroxyl radical, was detected in AEW prepared by double or triple electrolyses of 1% NaCl but not of 0.1% NaCl solution. Then the presence of hydrogen peroxide as a proposed source of hydroxyl radicals was examined using a combination of ESR and a Fenton reaction. The DMPO-OH signal was clearly detected, even in AEW prepared by single electrolysis of 0.1% NaCl solution, when ferrous sulfate was added to induce a Fenton reaction, indicating the presence of hydrogen peroxide in the AEW. Since sodium formate, a hydroxyl radical scavenger, did not affect the bactericidal activity of AEW, it is concluded that the radical is unlikely to contribute to the antimicrobial activity of AEW, although a small amount of the radical is produced from hydrogen peroxide. Dimethyl sulfoxide, the other hydroxyl radical scavenger used in the present study, canceled the bactericidal activity of AEW, accompanied by complete depletion of free available chlorine, suggesting that hypochlorous acid is probably a major contributor to the antimicrobial activity. CONCLUSIONS: It is strongly suggested that although hydrogen peroxide is present in AEW as a source of hydroxyl radicals, the antimicrobial activity of AEW does not depend on these radicals.

  6. Functionalization of hydroxyl terminated polybutadiene with ...

    Indian Academy of Sciences (India)

    Administrator

    The hydroxyl terminated polybutadiene (HTPB) used in this work was prepared by free radical polymerization using hydrogen peroxide as initiator and was received from HEMRL Pune, India, as a gift sample. The molecu- lar weight and polydispersity of the HTPB was deter- mined by using gel permeable chromatography ...

  7. New insight into electrochemical-induced synthesis of NiAl2O4/Al2O3: Synergistic effect of surface hydroxyl groups and magnetism for enhanced adsorptivity of Pd(II)

    International Nuclear Information System (INIS)

    Salleh, N.F.M.; Jalil, A.A.; Triwahyono, S.; Efendi, J.; Mukti, R.R.; Hameed, B.H.

    2015-01-01

    Graphical abstract: - Highlights: • The introduction of Ni to γ-Al 2 O 3 by electrolysis formed NiAl 2 O 4 spinels and NiO. • Physical mixed of NiO with γ-Al 2 O 3 only produced agglomerated NiO-Ni 0 . • Ni/Al 2 O 3 -E has remarkably higher degree of magnetism than Ni/Al 2 O 3 -PM. • Ni/Al 2 O 3 -E adsorbed Pd 2+ ions more effectively (q m = 40.3 mg/g) than Ni/Al 2 O 3 -PM. • Pd 2+ ions were adsorbed to both samples via magnetic attraction and ion exchange. - Abstract: A new promising adsorbent, Ni supported on γ-Al 2 O 3 was prepared in a simple electrolysis system (Ni/Al 2 O 3 -E) in minutes and was compared with the sample prepared by a physical mixing method (Ni/Al 2 O 3 -PM). The adsorbents were characterized by XRD, TEM, FTIR, 27 Al MAS NMR, XPS, and VSM. The results showed that besides NiO nanoparticles, a NiAl 2 O 4 spinel was also formed in Ni/Al 2 O 3 -E during the electrolysis via the dealumination and isomorphous substitution of Ni 2+ ions. In contrast, only agglomerated NiO was found in the Ni/Al 2 O 3 -PM. Adsorption test on removal of Pd 2+ ions from aqueous solution showed that the Pd 2+ ions were exchanged with the hydrogen atoms of the surface–OH groups of both adsorbents. Significantly, the Ni/Al 2 O 3 -E demonstrated a higher adsorption towards Pd 2+ ions than Ni/Al 2 O 3 -PM due to its remarkably higher degree of magnetism, which came from the NiAl 2 O 4 . The use of 0.1 g L −1 Ni/Al 2 O 3 -E gave the maximum monolayer adsorption capacity (q m ) of 40.3 mg g −1 at 303 K and pH 5. The Ni/Al 2 O 3 -E showed high potential for simultaneous removal of various noble and transition metal ions and could be also used repetitively without affecting the high adsorptivity for Pd 2+ ions. This work may provide promising adsorbents for recovery of various metals as well as other materials for such related applications

  8. A study of planar anchor groups for graphene-based single-molecule electronics.

    Science.gov (United States)

    Bailey, Steven; Visontai, David; Lambert, Colin J; Bryce, Martin R; Frampton, Harry; Chappell, David

    2014-02-07

    To identify families of stable planar anchor groups for use in single molecule electronics, we report detailed results for the binding energies of two families of anthracene and pyrene derivatives adsorbed onto graphene. We find that all the selected derivatives functionalized with either electron donating or electron accepting substituents bind more strongly to graphene than the parent non-functionalized anthracene or pyrene. The binding energy is sensitive to the detailed atomic alignment of substituent groups over the graphene substrate leading to larger than expected binding energies for -OH and -CN derivatives. Furthermore, the ordering of the binding energies within the anthracene and pyrene series does not simply follow the electron affinities of the substituents. Energy barriers to rotation or displacement on the graphene surface are much lower than binding energies for adsorption and therefore at room temperature, although the molecules are bound to the graphene, they are almost free to move along the graphene surface. Binding energies can be increased by incorporating electrically inert side chains and are sensitive to the conformation of such chains.

  9. A study of planar anchor groups for graphene-based single-molecule electronics

    Energy Technology Data Exchange (ETDEWEB)

    Bailey, Steven; Visontai, David; Lambert, Colin J., E-mail: c.lambert@lancaster.ac.uk [Department of Physics, Lancaster University, Lancaster LA1 4YB (United Kingdom); Bryce, Martin R. [Department of Chemistry, Durham University, Durham DH1 3LE (United Kingdom); Frampton, Harry; Chappell, David [BP Exploration Operating Company Limited, Chertsey Road, Sunbury on Thames, Middlesex TW16 7BP (United Kingdom)

    2014-02-07

    To identify families of stable planar anchor groups for use in single molecule electronics, we report detailed results for the binding energies of two families of anthracene and pyrene derivatives adsorbed onto graphene. We find that all the selected derivatives functionalized with either electron donating or electron accepting substituents bind more strongly to graphene than the parent non-functionalized anthracene or pyrene. The binding energy is sensitive to the detailed atomic alignment of substituent groups over the graphene substrate leading to larger than expected binding energies for –OH and –CN derivatives. Furthermore, the ordering of the binding energies within the anthracene and pyrene series does not simply follow the electron affinities of the substituents. Energy barriers to rotation or displacement on the graphene surface are much lower than binding energies for adsorption and therefore at room temperature, although the molecules are bound to the graphene, they are almost free to move along the graphene surface. Binding energies can be increased by incorporating electrically inert side chains and are sensitive to the conformation of such chains.

  10. A study of planar anchor groups for graphene-based single-molecule electronics

    Science.gov (United States)

    Bailey, Steven; Visontai, David; Lambert, Colin J.; Bryce, Martin R.; Frampton, Harry; Chappell, David

    2014-02-01

    To identify families of stable planar anchor groups for use in single molecule electronics, we report detailed results for the binding energies of two families of anthracene and pyrene derivatives adsorbed onto graphene. We find that all the selected derivatives functionalized with either electron donating or electron accepting substituents bind more strongly to graphene than the parent non-functionalized anthracene or pyrene. The binding energy is sensitive to the detailed atomic alignment of substituent groups over the graphene substrate leading to larger than expected binding energies for -OH and -CN derivatives. Furthermore, the ordering of the binding energies within the anthracene and pyrene series does not simply follow the electron affinities of the substituents. Energy barriers to rotation or displacement on the graphene surface are much lower than binding energies for adsorption and therefore at room temperature, although the molecules are bound to the graphene, they are almost free to move along the graphene surface. Binding energies can be increased by incorporating electrically inert side chains and are sensitive to the conformation of such chains.

  11. A study of planar anchor groups for graphene-based single-molecule electronics

    International Nuclear Information System (INIS)

    Bailey, Steven; Visontai, David; Lambert, Colin J.; Bryce, Martin R.; Frampton, Harry; Chappell, David

    2014-01-01

    To identify families of stable planar anchor groups for use in single molecule electronics, we report detailed results for the binding energies of two families of anthracene and pyrene derivatives adsorbed onto graphene. We find that all the selected derivatives functionalized with either electron donating or electron accepting substituents bind more strongly to graphene than the parent non-functionalized anthracene or pyrene. The binding energy is sensitive to the detailed atomic alignment of substituent groups over the graphene substrate leading to larger than expected binding energies for –OH and –CN derivatives. Furthermore, the ordering of the binding energies within the anthracene and pyrene series does not simply follow the electron affinities of the substituents. Energy barriers to rotation or displacement on the graphene surface are much lower than binding energies for adsorption and therefore at room temperature, although the molecules are bound to the graphene, they are almost free to move along the graphene surface. Binding energies can be increased by incorporating electrically inert side chains and are sensitive to the conformation of such chains

  12. Effect of Environmental Enrichment on Singly- and Group-Housed Squirrel Monkeys

    Science.gov (United States)

    Spring, Sarah E.; Clifford, James O.; Tomko, David L.; Hargens, Alan R. (Technical Monitor)

    1996-01-01

    Nonhuman primates display an interest in novel places, habituate to new situations, and spend most of their daily activity in the wild in large groups engaging in feeding behaviors. Captivity changes these behaviors, and disrupts normal social hierarchies. In captivity, animals may exhibit stereotypical behaviors which are thought to indicate decreased psychological well-being (PWB). If an animal's behaviors can be made to approach those seen in the wild, and stereotypical behaviors are minimal it is assumed that PWB is adequate. Environmental enrichment (EE) devices have been used to address the Animal Welfare Act's requirement that the PWB of captive nonhuman primates be considered. The purpose of the present study was to examine whether various EE devices improve the PWB of captive squirrel monkeys. The present study used behavioral observation to quantify the effectiveness of several EE devices in reducing stereotypical behaviors in squirrel monkeys housed singly or in groups. Results showed that the EE devices used did not affect the expression of normal or stereotypical behaviors, but that the type of housing did.

  13. Hydroxyl tagging velocimetry in a supersonic flow over a cavity

    International Nuclear Information System (INIS)

    Pitz, Robert W.; Lahr, Michael D.; Douglas, Zachary W.; Wehrmeyer, Joseph A.; Hu Shengteng; Carter, Campbell D.; Hsu, Kuang-Yu; Lum, Chee; Koochesfahani, Manoochehr M.

    2005-01-01

    Hydroxyl tagging velocimetry (HTV) measurements of velocity were made in a Mach 2 (M 2) flow with a wall cavity. In the HTV method, ArF excimer laser (193 nm) beams pass through a humid gas and dissociate H2O into H + OH to form a tagging grid of OH molecules. In this study, a 7x7 grid of hydroxyl (OH) molecules is tracked by planar laser-induced fluorescence. The grid motion over a fixed time delay yields about 50 velocity vectors of the two-dimensional flow in the plane of the laser sheets. Velocity precision is limited by the error in finding the crossing location of the OH lines written by the excimer tag laser. With a signal-to-noise ratio of about 10 for the OH lines, the determination of the crossing location is expected to be accurate within ±0.1 pixels. Velocity precision within the freestream, where the turbulence is low, is consistent with this error. Instantaneous, single-shot measurements of two-dimensional flow patterns were made in the nonreacting M 2 flow with a wall cavity under low- and high-pressure conditions. The single-shot profiles were analyzed to yield mean and rms velocity profiles in the M 2 nonreacting flow

  14. New insight into electrochemical-induced synthesis of NiAl{sub 2}O{sub 4}/Al{sub 2}O{sub 3}: Synergistic effect of surface hydroxyl groups and magnetism for enhanced adsorptivity of Pd(II)

    Energy Technology Data Exchange (ETDEWEB)

    Salleh, N.F.M. [Department of Chemical Engineering, Faculty of Chemical Engineering, Universiti Teknologi Malaysia, 81310 UTM Johor Bahru, Johor (Malaysia); Jalil, A.A., E-mail: aishah@cheme.utm.my [Department of Chemical Engineering, Faculty of Chemical Engineering, Universiti Teknologi Malaysia, 81310 UTM Johor Bahru, Johor (Malaysia); Centre of Hydrogen Energy, Institute of Future Energy, Universiti Teknologi Malaysia, 81310 UTM Johor Bahru, Johor (Malaysia); Triwahyono, S. [Department of Chemistry, Faculty of Science, Universiti Teknologi Malaysia, 81310 UTM Johor Bahru, Johor (Malaysia); Efendi, J. [Department of Chemistry, Universitas Negeri Padang, Jl. Prof. Hamka, Air Tawar, Padang, West Sumatera (Indonesia); Mukti, R.R. [Division of Inorganic and Physical Chemistry, Faculty of Mathematics and Natural Science, Institut Teknologi Bandung, Jl Ganesha No 10, Bandung 40132 (Indonesia); Hameed, B.H. [School of Chemical Engineering, Engineering Campus, Universiti Sains Malaysia, 14300 Nibong Tebal, Penang (Malaysia)

    2015-09-15

    Graphical abstract: - Highlights: • The introduction of Ni to γ-Al{sub 2}O{sub 3} by electrolysis formed NiAl{sub 2}O{sub 4} spinels and NiO. • Physical mixed of NiO with γ-Al{sub 2}O{sub 3} only produced agglomerated NiO-Ni{sup 0}. • Ni/Al{sub 2}O{sub 3}-E has remarkably higher degree of magnetism than Ni/Al{sub 2}O{sub 3}-PM. • Ni/Al{sub 2}O{sub 3}-E adsorbed Pd{sup 2+} ions more effectively (q{sub m} = 40.3 mg/g) than Ni/Al{sub 2}O{sub 3}-PM. • Pd{sup 2+} ions were adsorbed to both samples via magnetic attraction and ion exchange. - Abstract: A new promising adsorbent, Ni supported on γ-Al{sub 2}O{sub 3} was prepared in a simple electrolysis system (Ni/Al{sub 2}O{sub 3}-E) in minutes and was compared with the sample prepared by a physical mixing method (Ni/Al{sub 2}O{sub 3}-PM). The adsorbents were characterized by XRD, TEM, FTIR, {sup 27}Al MAS NMR, XPS, and VSM. The results showed that besides NiO nanoparticles, a NiAl{sub 2}O{sub 4} spinel was also formed in Ni/Al{sub 2}O{sub 3}-E during the electrolysis via the dealumination and isomorphous substitution of Ni{sup 2+} ions. In contrast, only agglomerated NiO was found in the Ni/Al{sub 2}O{sub 3}-PM. Adsorption test on removal of Pd{sup 2+} ions from aqueous solution showed that the Pd{sup 2+} ions were exchanged with the hydrogen atoms of the surface–OH groups of both adsorbents. Significantly, the Ni/Al{sub 2}O{sub 3}-E demonstrated a higher adsorption towards Pd{sup 2+} ions than Ni/Al{sub 2}O{sub 3}-PM due to its remarkably higher degree of magnetism, which came from the NiAl{sub 2}O{sub 4}. The use of 0.1 g L{sup −1} Ni/Al{sub 2}O{sub 3}-E gave the maximum monolayer adsorption capacity (q{sub m}) of 40.3 mg g{sup −1} at 303 K and pH 5. The Ni/Al{sub 2}O{sub 3}-E showed high potential for simultaneous removal of various noble and transition metal ions and could be also used repetitively without affecting the high adsorptivity for Pd{sup 2+} ions. This work may provide promising

  15. Comparing single-tree selection, group selection, and clearcutting for regenerating oaks and pines in the Missouri Ozarks

    Science.gov (United States)

    Randy G. Jensen; John M. Kabrick

    2008-01-01

    In the Missouri Ozarks, there is considerable concern about the effectiveness of the uneven-aged methods of single-tree selection and group selection for oak (Quercus L.) and shortleaf pine (Pinus echinata Mill.) regeneration. We compared the changes in reproduction density of oaks and pine following harvesting by single-tree...

  16. Cognitive behavioral therapy for depression among adults in Japanese clinical settings: a single-group study

    Science.gov (United States)

    2010-01-01

    Background Empirical support for cognitive behavioral therapy (CBT) for treating Japanese patients with major depression is lacking, therefore, a feasibility study of CBT for depression in Japanese clinical settings is urgently required. Findings A culturally adapted, 16-week manualized individual CBT program for Japanese patients with major depressive disorder was developed. A total of 27 patients with major depression were enrolled in a single-group study with the purpose of testing the feasibility of the program. Twenty six patients (96%) completed the study. The mean total score on the Beck Depression Inventory-II (BDI-II) for all patients (Intention-to-treat sample) improved from 32.6 to 11.7, with a mean change of 20.8 (95% confidence interval: 17.0 to 24.8). Within-group effect size at the endpoint assessment was 2.64 (Cohen's d). Twenty-one patients (77.7%) showed treatment response and 17 patients (63.0%) achieved remission at the end of the program. Significant improvement was observed in measurement of subjective and objective depression severity (assessed by BDI-II, Quick Inventory of Depressive Symptomatology-Self Rated, and Hamilton Depression Rating Scale), dysfunctional attitude (assessed by Dysfunctional Attitude Scale), global functioning (assessed by Global Assessment of Functioning of DSM-IV) and subjective well-being (assessed by WHO Subjective Well-being Inventory) (all p values < 0.001). Conclusions Our manualized treatment comprised of a 16-week individual CBT program for major depression appears feasible and may achieve favorable treatment outcomes among Japanese patients with major depression. Further research involving a larger sample in a randomized, controlled trial design is warranted. Trial registration UMIN-CTR UMIN000002542. PMID:20529252

  17. Cognitive behavioral therapy for depression among adults in Japanese clinical settings: a single-group study

    Directory of Open Access Journals (Sweden)

    Kikuchi Toshiaki

    2010-06-01

    Full Text Available Abstract Background Empirical support for cognitive behavioral therapy (CBT for treating Japanese patients with major depression is lacking, therefore, a feasibility study of CBT for depression in Japanese clinical settings is urgently required. Findings A culturally adapted, 16-week manualized individual CBT program for Japanese patients with major depressive disorder was developed. A total of 27 patients with major depression were enrolled in a single-group study with the purpose of testing the feasibility of the program. Twenty six patients (96% completed the study. The mean total score on the Beck Depression Inventory-II (BDI-II for all patients (Intention-to-treat sample improved from 32.6 to 11.7, with a mean change of 20.8 (95% confidence interval: 17.0 to 24.8. Within-group effect size at the endpoint assessment was 2.64 (Cohen's d. Twenty-one patients (77.7% showed treatment response and 17 patients (63.0% achieved remission at the end of the program. Significant improvement was observed in measurement of subjective and objective depression severity (assessed by BDI-II, Quick Inventory of Depressive Symptomatology-Self Rated, and Hamilton Depression Rating Scale, dysfunctional attitude (assessed by Dysfunctional Attitude Scale, global functioning (assessed by Global Assessment of Functioning of DSM-IV and subjective well-being (assessed by WHO Subjective Well-being Inventory (all p values Conclusions Our manualized treatment comprised of a 16-week individual CBT program for major depression appears feasible and may achieve favorable treatment outcomes among Japanese patients with major depression. Further research involving a larger sample in a randomized, controlled trial design is warranted. Trial registration UMIN-CTR UMIN000002542.

  18. Thermophysical properties of hydroxyl ammonium ionic liquids

    International Nuclear Information System (INIS)

    Kurnia, K.A.; Wilfred, C.D.; Murugesan, T.

    2009-01-01

    The thermophysical properties of hydroxyl ammonium ionic liquids: density ρ, T = (293.15 to 363.15) K; dynamic viscosity η, T = (298.2 to 348.2) K; and refractive indices n D , T = (293.15 to 333.15) K have been measured. The coefficients of thermal expansion α, values were calculated from the experimental density results using an empirical correlation for T = (293.15 to 363.15) K. The variation of volume expansion of ionic liquids studied was found to be independent of temperature within the range covered in the present work. The thermal decomposition temperature 'T d ' for all the six hydroxyl ammonium ionic liquids is also investigated using thermogravimetric analyzer (TGA)

  19. Nanocomposites of ferroelectric polymers with surface-hydroxylated BaTiO 3 nanoparticles for energy storage applications

    KAUST Repository

    Almadhoun, Mahmoud Nassar Mahmoud; Bhansali, Unnat Sampatraj; Alshareef, Husam N.

    2012-01-01

    nanofillers (<100 nm) with hydroxyl groups results in as much as two orders of magnitude reduction in the leakage current of nanocomposite thin-film capacitors. This reduction is observed concurrently with the enhancement of the effective permittivity

  20. Social support and education groups for single mothers: a randomized controlled trial of a community-based program.

    Science.gov (United States)

    Lipman, Ellen L; Boyle, Michael H

    2005-12-06

    Members of families headed by single mothers are at increased risk of psychosocial disadvantage and mental health problems. We assessed the effect of a community-based program of social support and education groups for single mothers of young children on maternal well-being and parenting. We recruited 116 single mothers of children 3 to 9 years old through community advertisements. Eligible mothers were randomly assigned either to participate in a 10-week program of group sessions (1.5 hours per week) offering social support and education, with a parallel children's activity group, or to receive a standard list of community resources and the option to participate in group sessions at the end of the follow-up period. Interviewers blinded to the randomization collected assessment data from all mothers at baseline and at 3 follow-up visits (immediately after the intervention and at 3 and 6 months after the intervention). Outcome measures were self-reported mood, self-esteem, social support and parenting. Between February 2000 and April 2003, the program was offered to 9 groups of single mothers. Most of the mothers in the trial reported high levels of financial and mental health problems. In the short term (after the intervention), mothers in the intervention group had improved scores for mood (p effect = 0.55) and self-esteem (p effect = 0.29) compared with mothers in the control group; scores for the other 2 measures did not differ between the groups. Growth curve analysis of program effects over the follow-up period showed improvement in all 4 outcomes, with no significant difference between the intervention and control groups. This community-based program of group sessions offering social support and education to low-income single mothers had positive short-term effects on mood and self-esteem but not on social support and parenting. Longer follow-up showed attenuation of these effects.

  1. Growth and study of some gel grown group II single crystals of iodate

    Indian Academy of Sciences (India)

    Unknown

    Abstract. Single crystals of calcium iodate and barium iodate were grown by simple gel technique by single diffusion method. The optimum conditions were established by varying various parameters such as pH of gel solution, gel concentration, gel setting time, concentration of the reactants etc. Crystals having different.

  2. Structure and Dynamics of Hydroxyl-Functionalized Protic Ammonium Carboxylate Ionic Liquids.

    Science.gov (United States)

    Thummuru, Dhileep Nagi Reddy; Mallik, Bhabani S

    2017-10-26

    We performed classical molecular dynamics simulations to investigate the structure and dynamics of protic ionic liquids, 2-hydroxy ethylammonium acetate, ethylammonium hydroxyacetate, and 2-hydroxyethylammonium hydroxyacetate at ambient conditions. Structural properties such as density, radial distribution functions, spatial distribution functions, and structure factors have been calculated. Dynamic properties such as mean square displacements, as well as residence and hydrogen bond dynamics have also been calculated. Hydrogen bond lifetimes and residence times change with the addition of hydroxyl groups. We observe that when a hydroxyl group is present on the cation, dynamics become very slow and it forms a strong hydrogen bond with carboxylate oxygen atoms of the anion. The hydroxyl functionalized ILs show more dynamic diversity than structurally similar ILs.

  3. - Hydroxylated Anthraquinones Produced by Geosmithia species

    Czech Academy of Sciences Publication Activity Database

    Stodůlková, Eva; Kolařík, Miroslav; Křesinová, Zdena; Kuzma, Marek; Šulc, Miroslav; Man, Petr; Novák, Petr; Maršík, Petr; Landa, Přemysl; Olšovská, Jana; Chudíčková, Milada; Pažoutová, Sylvie; Černý, J.; Bella, J.; Flieger, Miroslav

    2009-01-01

    Roč. 54, č. 3 (2009), s. 179-187 ISSN 0015-5632 R&D Projects: GA AV ČR KAN200200651; GA MŠk LC07017; GA MŠk 1M0506; GA ČR GP203/05/P575 Grant - others:CZ(CZ) 205/2004 Institutional research plan: CEZ:AV0Z50200510; CEZ:AV0Z50380511 Keywords : hydroxylated anthraquinones * staphylococcus aureus * mammalian cell lines Subject RIV: EE - Microbiology, Virology Impact factor: 0.978, year: 2009

  4. Hydroxyl radical induced transformation of phenylurea herbicides: A theoretical study

    International Nuclear Information System (INIS)

    Mile, Viktória; Harsányi, Ildikó; Kovács, Krisztina; Földes, Tamás; Takács, Erzsébet; Wojnárovits, László

    2017-01-01

    Aromatic ring hydroxylation reactions occurring during radiolysis of aqueous solutions are studied on the example of phenylurea herbicides by Density Functional Theory calculations. The effect of the aqueous media is taken into account by using the Solvation Model Based on Density model. Hydroxyl radical adds to the ring because the activation free energies (0.4–47.2 kJ mol −1 ) are low and also the Gibbs free energies have high negative values ((−27.4) to (−5.9) kJ mol −1 ). According to the calculations in most of cases the ortho- and para-addition is preferred in agreement with the experimental results. In these reactions hydroxycyclohexadienyl type radicals form. In a second type reaction, when loss of chlorine atom takes place, OH/Cl substitution occurs without cyclohexadienyl type intermediate. - Highlights: • Attack of • OH to aniline, phenol, fenuron, monuron, diuron was studied by DFT. • Ortho-para directing is suggested with –NH 2 , –OH and –NHCON(CH 3 ) 2 groups. • • OH addition to the ring gives hydroxycyclohexadienyl radical. • Attack at C-Cl leads to • OH/Cl substitution without cyclohexadienyl intermediate.

  5. Mechanism of aromatic hydroxylation of lidocaine at a Pt electrode under acidic conditions

    International Nuclear Information System (INIS)

    Gul, Turan; Bischoff, Rainer; Permentier, Hjalmar P.

    2017-01-01

    Aromatic hydroxylation reactions, which are mainly catalyzed by cytochrome P450 (CYP) enzymes in vivo, are some of the most important reactions of Phase I metabolism, because insertion of a hydroxyl group into a lipophilic drug compound increases its hydrophilicity and prepares it for subsequent Phase II metabolic conjugation reactions as a prerequisite to excretion. Aromatic hydroxylation metabolites of pharmaceuticals may be obtained through various synthetic and enzymatic methods Electrochemical oxidation is an alternative with advantages in terms of mild reaction conditions and less hazardous chemicals. In the present study, we report that aromatic hydroxylation metabolites of lidocaine can be readily obtained electrochemically under aqueous acidic conditions at platinum electrodes. Our results show that the dominant N-dealkylation reaction can be suppressed by decreasing the solution pH below 0.5 resulting in selective 3-hydroxylidocaine, which is an in vivo metabolite of lidocaine. Experiments in 18 O labelled water indicated that water is the primary source of oxygen, while dissolved molecular oxygen contributes to a minor extent to the hydroxylation reaction.

  6. A single blind randomized control trial on support groups for Chinese persons with mild dementia

    Directory of Open Access Journals (Sweden)

    Young DKW

    2014-12-01

    Full Text Available Daniel KW Young,1 Timothy CY Kwok,2 Petrus YN Ng1 1Department of Social Work, Hong Kong Baptist University, Kowloon Tong, Hong Kong; 2Department of Medicine and Therapeutics, The Chinese University of Hong Kong, Shatin, Hong Kong Purpose: Persons with mild dementia experience multiple losses and manifest depressive symptoms. This research study aimed to evaluate the effectiveness of a support group led by a social worker for Chinese persons with mild dementia. Research methods: Participants were randomly assigned to either a ten-session support group or a control group. Standardized assessment tools were used for data collection at pretreatment and post-treatment periods by a research assistant who was kept blind to the group assignment of the participants. Upon completion of the study, 20 treatment group participants and 16 control group participants completed all assessments. Results: At baseline, the treatment and control groups did not show any significant difference on all demographic variables, as well as on all baseline measures; over one-half (59% of all the participants reported having depression, as assessed by a Chinese Geriatric Depression Scale score ≥8. After completing the support group, the depressive mood of the treatment group participants reduced from 8.83 (standard deviation =2.48 to 7.35 (standard deviation =2.18, which was significant (Wilcoxon signed-rank test; P=0.017, P<0.05, while the control group’s participants did not show any significant change. Conclusion: This present study supports the efficacy and effectiveness of the support group for persons with mild dementia in Chinese society. In particular, this present study shows that a support group can reduce depressive symptoms for participants. Keywords: support group, mild dementia, Chinese, depression

  7. Mechanism of the N-Hydroxylation of Primary and Secondary Amines by Cytochrome P450

    DEFF Research Database (Denmark)

    Seger, Signe T.; Rydberg, Patrik; Olsen, Lars

    2015-01-01

    Cytochrome P450 enzymes (CYPs) metabolize alkyl- and arylamines, generating several different products. For the primary and secondary amines, some of these reactions result in hydroxylated amines, which may be toxic. Thus, when designing new drugs containing amine groups, it is important to be able...... to predict if a given compound will be a substrate for CYPs, in order to avoid toxic metabolites, and hence to understand the mechanism that is utilized by CYPs. Two possible mechanisms, for the N-hydroxylation of primary and secondary amines mediated by CYPs, are studied by density functional theory (DFT...

  8. Diameter grouping in bulk samples of single-walled carbon nanotubes from optical absorption spectroscopy

    NARCIS (Netherlands)

    Golden, M.S.; Fink, J.; Dunsch, L.; Bauer, H.-D.; Reibold, M.; Knupfer, M.; Friedlein, R.; Pichler, T.; Jost, O.

    1999-01-01

    The influence of the synthesis parameters on the mean characteristics of single-wall carbon nanotubes in soot produced by the laser vaporization of graphite has been analyzed using optical absorption spectroscopy. The abundance and mean diameter of the nanotubes were found to be most influenced by

  9. Summary report of the group on single-particle nonlinear dynamics

    International Nuclear Information System (INIS)

    Axinescu, S.; Bartolini, R.; Bazzani, A.

    1996-10-01

    This report summarizes the research on single-particle nonlinear beam dynamics. It discusses the following topics: analytical and semi-analytical tools; early prediction of the dynamic aperture; how the results are commonly presented; Is the mechanism of the dynamic aperture understand; ripple effects; and beam-beam effects

  10. Single crystal X-ray structural features of aromatic compounds having a pentafluorosulfuranyl (SF5) functional group

    Czech Academy of Sciences Publication Activity Database

    Du, J.; Hua, G.; Beier, Petr; Slawin, A. M. Z.; Woollins, J. D.

    2017-01-01

    Roč. 28, č. 3 (2017), s. 723-733 ISSN 1040-0400 Institutional support: RVO:61388963 Keywords : pentafluorosulfuranyl (SF5) group * aromatic compounds * single crystal X-ray structure * intramolecular interactions * intermolecular interactions Subject RIV: CC - Organic Chemistry OBOR OECD: Organic chemistry Impact factor: 1.582, year: 2016

  11. Reactions of OH-radicals with hydroxylated and methoxylated benzoic acids and cinnamic acids. Radiation-induced chemical changes in mushrooms

    International Nuclear Information System (INIS)

    Gaisberger, B.

    2001-05-01

    In the first part of this work the radiation induced chemical changes of methoxylated and hydroxylated benzoic acids and cinnamic acids were investigated. Methoxylated compounds were also used as model components for acid derivatives with no free-OH groups. The latter are essentials parts of vegetable foodstuff. A comparison of the radiolytic behaviour of single substituted methoxy- and hydroxybenzoic acids was given at first, data of literature was included. The priority of the investigation was the hydroxylation process induced by OH-radicals. The OH-adduct distribution is generally the same for the hydroxy- as well as for the methoxybenzoic acid isomers. This could be proved by oxidation of these OH-adducts with K 3 Fe(CN) 6 . In the presence of air 68-77 % of the hydroxybenzoic acids are converted into hydroxylation products, whereas with the methoxylated acids this reaction leads only to about 10%. An explanation gives the different decay pathways of the intermediate peroxylradical. The multiple methoxy- and hydroxybenzoic acids show three different reaction possibilities: hydroxylation, replacement of -OCH 3 by -OH and -in case of the cinnamic acids-oxidative decomposition of the rest of the propenic acid under formation of the corresponding benzaldehydes. All these reactions can be expected when irradiating foodstuff, containing these acid compounds. The characteristic formation of these components and their linear dose/concentration relationship make these substrates very promising for the use as markers for irradiation treatment of foodstuff. The second part of this work deals with the gamma-radiation induced chemical changes in mushrooms. The irradiated and non-irradiated samples were freeze-dried and purified from matrix components chromatographically on polyamid columns. In case of the phenolic compounds for 4-hydroxybenzoic acid and three unknown components linear dose/concentration relationships could be obtained. Two of these unknown compounds seem

  12. Hydroxylation of nitro-(pentafluorosulfanyl)benzenes via vicarious nucleophilic substitution of hydrogen

    Czech Academy of Sciences Publication Activity Database

    Beier, Petr; Pastýříková, Tereza

    2011-01-01

    Roč. 52, č. 34 (2011), s. 4392-4394 ISSN 0040-4039 R&D Projects: GA ČR GAP207/11/0344 Institutional research plan: CEZ:AV0Z40550506 Keywords : pentafluorosulfanyl group * vicarious nucleophilic substitution * hydroxylation Subject RIV: CC - Organic Chemistry Impact factor: 2.683, year: 2011

  13. Hydroxyl pyridine containing polybenzimidazole membranes for proton exchange membrane fuel cells

    DEFF Research Database (Denmark)

    Yang, Jingshuai; Xu, Yixin; Zhou, Lu

    2013-01-01

    A polybenzimidazole variant polymer containing hydroxyl pyridine groups, termed as OHPyPBI, was synthesized from 3,3'-diaminobenzidine tetrahydrochloride and 4-hydroxy-2,6-pyridinedicarboxylic acid. The thermal-oxidative stability of the OHPyPBI polymer was as high as that of poly[2,2'-(m-phenyle...

  14. Discrimination of Communication Vocalizations by Single Neurons and Groups of Neurons in the Auditory Midbrain

    OpenAIRE

    Schneider, David M.; Woolley, Sarah M. N.

    2010-01-01

    Many social animals including songbirds use communication vocalizations for individual recognition. The perception of vocalizations depends on the encoding of complex sounds by neurons in the ascending auditory system, each of which is tuned to a particular subset of acoustic features. Here, we examined how well the responses of single auditory neurons could be used to discriminate among bird songs and we compared discriminability to spectrotemporal tuning. We then used biologically realistic...

  15. Summary of Group Development and Testing for Single Shell Tank Closure at Hanford

    International Nuclear Information System (INIS)

    Harbour, John R.

    2005-01-01

    This report is a summary of the bench-scale and large scale experimental studies performed by Savannah River National Laboratory for CH2M HILL to develop grout design mixes for possible use in producing fill materials as a part of Tank Closure of the Single-Shell Tanks at Hanford. The grout development data provided in this report demonstrates that these design mixes will produce fill materials that are ready for use in Hanford single shell tank closure. The purpose of this report is to assess the ability of the proposed grout specifications to meet the current requirements for successful single shell tank closure which will include the contracting of services for construction and operation of a grout batch plant. The research and field experience gained by SRNL in the closure of Tanks 17F and 20F at the Savannah River Site was leveraged into the grout development efforts for Hanford. It is concluded that the three Hanford grout design mixes provide fill materials that meet the current requirements for successful placement. This conclusion is based on the completion of recommended testing using Hanford area materials by the operators of the grout batch plant. This report summarizes the regulatory drivers and the requirements for grout mixes as tank fill material. It is these requirements for both fresh and cured grout properties that drove the development of the grout formulations for the stabilization, structural and capping layers

  16. Kinetics of hydrogen peroxide decomposition by catalase: hydroxylic solvent effects.

    Science.gov (United States)

    Raducan, Adina; Cantemir, Anca Ruxandra; Puiu, Mihaela; Oancea, Dumitru

    2012-11-01

    The effect of water-alcohol (methanol, ethanol, propan-1-ol, propan-2-ol, ethane-1,2-diol and propane-1,2,3-triol) binary mixtures on the kinetics of hydrogen peroxide decomposition in the presence of bovine liver catalase is investigated. In all solvents, the activity of catalase is smaller than in water. The results are discussed on the basis of a simple kinetic model. The kinetic constants for product formation through enzyme-substrate complex decomposition and for inactivation of catalase are estimated. The organic solvents are characterized by several physical properties: dielectric constant (D), hydrophobicity (log P), concentration of hydroxyl groups ([OH]), polarizability (α), Kamlet-Taft parameter (β) and Kosower parameter (Z). The relationships between the initial rate, kinetic constants and medium properties are analyzed by linear and multiple linear regression.

  17. Effective L-Tyrosine Hydroxylation by Native and Immobilized Tyrosinase.

    Directory of Open Access Journals (Sweden)

    Małgorzata Cieńska

    Full Text Available Hydroxylation of L-tyrosine to 3,4-dihydroxyphenylalanine (L-DOPA by immobilized tyrosinase in the presence of ascorbic acid (AH2, which reduces DOPA-quinone to L-DOPA, is characterized by low reaction yields that are mainly caused by the suicide inactivation of tyrosinase by L-DOPA and AH2. The main aim of this work was to compare processes with native and immobilized tyrosinase to identify the conditions that limit suicide inactivation and produce substrate conversions to L-DOPA of above 50% using HPLC analysis. It was shown that immobilized tyrosinase does not suffer from partitioning and diffusion effects, allowing a direct comparison of the reactions performed with both forms of the enzyme. In typical processes, additional aeration was applied and boron ions to produce the L-DOPA and AH2 complex and hydroxylamine to close the cycle of enzyme active center transformations. It was shown that the commonly used pH 9 buffer increased enzyme stability, with concomitant reduced reactivity of 76%, and that under these conditions, the maximal substrate conversion was approximately 25 (native to 30% (immobilized enzyme. To increase reaction yield, the pH of the reaction mixture was reduced to 8 and 7, producing L-DOPA yields of approximately 95% (native enzyme and 70% (immobilized. A three-fold increase in the bound enzyme load achieved 95% conversion in two successive runs, but in the third one, tyrosinase lost its activity due to strong suicide inactivation caused by L-DOPA processing. In this case, the cost of the immobilized enzyme preparation is not overcome by its reuse over time, and native tyrosinase may be more economically feasible for a single use in L-DOPA production. The practical importance of the obtained results is that highly efficient hydroxylation of monophenols by tyrosinase can be obtained by selecting the proper reaction pH and is a compromise between complexation and enzyme reactivity.

  18. Effective L-Tyrosine Hydroxylation by Native and Immobilized Tyrosinase

    Science.gov (United States)

    Lewańczuk, Marcin; Koźlecki, Tomasz; Liesiene, Jolanta; Bryjak, Jolanta

    2016-01-01

    Hydroxylation of L-tyrosine to 3,4-dihydroxyphenylalanine (L-DOPA) by immobilized tyrosinase in the presence of ascorbic acid (AH2), which reduces DOPA-quinone to L-DOPA, is characterized by low reaction yields that are mainly caused by the suicide inactivation of tyrosinase by L-DOPA and AH2. The main aim of this work was to compare processes with native and immobilized tyrosinase to identify the conditions that limit suicide inactivation and produce substrate conversions to L-DOPA of above 50% using HPLC analysis. It was shown that immobilized tyrosinase does not suffer from partitioning and diffusion effects, allowing a direct comparison of the reactions performed with both forms of the enzyme. In typical processes, additional aeration was applied and boron ions to produce the L-DOPA and AH2 complex and hydroxylamine to close the cycle of enzyme active center transformations. It was shown that the commonly used pH 9 buffer increased enzyme stability, with concomitant reduced reactivity of 76%, and that under these conditions, the maximal substrate conversion was approximately 25 (native) to 30% (immobilized enzyme). To increase reaction yield, the pH of the reaction mixture was reduced to 8 and 7, producing L-DOPA yields of approximately 95% (native enzyme) and 70% (immobilized). A three-fold increase in the bound enzyme load achieved 95% conversion in two successive runs, but in the third one, tyrosinase lost its activity due to strong suicide inactivation caused by L-DOPA processing. In this case, the cost of the immobilized enzyme preparation is not overcome by its reuse over time, and native tyrosinase may be more economically feasible for a single use in L-DOPA production. The practical importance of the obtained results is that highly efficient hydroxylation of monophenols by tyrosinase can be obtained by selecting the proper reaction pH and is a compromise between complexation and enzyme reactivity. PMID:27711193

  19. Effective L-Tyrosine Hydroxylation by Native and Immobilized Tyrosinase.

    Science.gov (United States)

    Cieńska, Małgorzata; Labus, Karolina; Lewańczuk, Marcin; Koźlecki, Tomasz; Liesiene, Jolanta; Bryjak, Jolanta

    2016-01-01

    Hydroxylation of L-tyrosine to 3,4-dihydroxyphenylalanine (L-DOPA) by immobilized tyrosinase in the presence of ascorbic acid (AH2), which reduces DOPA-quinone to L-DOPA, is characterized by low reaction yields that are mainly caused by the suicide inactivation of tyrosinase by L-DOPA and AH2. The main aim of this work was to compare processes with native and immobilized tyrosinase to identify the conditions that limit suicide inactivation and produce substrate conversions to L-DOPA of above 50% using HPLC analysis. It was shown that immobilized tyrosinase does not suffer from partitioning and diffusion effects, allowing a direct comparison of the reactions performed with both forms of the enzyme. In typical processes, additional aeration was applied and boron ions to produce the L-DOPA and AH2 complex and hydroxylamine to close the cycle of enzyme active center transformations. It was shown that the commonly used pH 9 buffer increased enzyme stability, with concomitant reduced reactivity of 76%, and that under these conditions, the maximal substrate conversion was approximately 25 (native) to 30% (immobilized enzyme). To increase reaction yield, the pH of the reaction mixture was reduced to 8 and 7, producing L-DOPA yields of approximately 95% (native enzyme) and 70% (immobilized). A three-fold increase in the bound enzyme load achieved 95% conversion in two successive runs, but in the third one, tyrosinase lost its activity due to strong suicide inactivation caused by L-DOPA processing. In this case, the cost of the immobilized enzyme preparation is not overcome by its reuse over time, and native tyrosinase may be more economically feasible for a single use in L-DOPA production. The practical importance of the obtained results is that highly efficient hydroxylation of monophenols by tyrosinase can be obtained by selecting the proper reaction pH and is a compromise between complexation and enzyme reactivity.

  20. ABO Blood Group and Endometrial Carcinoma: A Preliminary Single-Center Experience from Saudi Arabia.

    Science.gov (United States)

    Abu-Zaid, Ahmed; Alsabban, Mohannad; Abuzaid, Mohammed; Alomar, Osama; Al-Badawi, Ismail A; Salem, Hany

    2017-12-18

    Inherited ABO blood groups have been shown to play possible contributions in the pathogenesis of various gynecologic and non-gynecologic carcinomas. With regard to gynecologic carcinomas, there is a confined number of studies that explored the relationship between ABO blood group and endometrial carcinoma (EC) in the PubMed-indexed literature. To the best of our knowledge, no such study has ever been conducted in Saudi Arabia. Our study has two objectives: (I) to determine the prevalence of ABO blood groups among Saudi patients with EC, and (II) to explore the relationship between ABO blood group and several clinico-pathological prognostic parameters (namely: menopausal status [age], body mass index [BMI], tumor grade, FIGO [Fédération Internationale de Gynécologie et d'Obstétrique] stage and recurrence) in Saudi patients with EC. A retrospective cross-sectional study from 01-January-2010 to 31-July-2014 was conducted at King Faisal Specialist Hospital & Research Centre, Riyadh, Saudi Arabia - a referral tertiary healthcare institute. One-hundred and fourteen patients (n=114) were included in the study. Clinico-pathological data were extrapolated from medical records, and their association with ABO blood groups were evaluated. Categorical data were presented as number of cases (n) and percentages (%). Two-tailed Chi-square test was used for univariate analysis. For all purposes, p values 28 kg/m 2 (84.2%), diagnosed with early FIGO stage I-II (76.3%) and developed no recurrence (86.8%). The frequencies of ABO blood group types A, B, AB, and O were 28.1%, 12.3%, 3.5% and 56.1%, respectively. When ABO blood groups were analyzed as four different types (A, B, AB and O), O-type was the most common ABO blood group in pre- and post-menopausal EC patients (43.8% and 58.2%, respectively; p=0.14). There were no statistically significant correlations between ABO blood groups and all the examined clinico-pathological factors. Moreover, when ABO blood groups were

  1. A randomised, single-blind, single-dose, three-arm, parallel-group study in healthy subjects to demonstrate pharmacokinetic equivalence of ABP 501 and adalimumab.

    Science.gov (United States)

    Kaur, Primal; Chow, Vincent; Zhang, Nan; Moxness, Michael; Kaliyaperumal, Arunan; Markus, Richard

    2017-03-01

    To demonstrate pharmacokinetic (PK) similarity of biosimilar candidate ABP 501 relative to adalimumab reference product from the USA and European Union (EU) and evaluate safety, tolerability and immunogenicity of ABP 501. Randomised, single-blind, single-dose, three-arm, parallel-group study; healthy subjects were randomised to receive ABP 501 (n=67), adalimumab (USA) (n=69) or adalimumab (EU) (n=67) 40 mg subcutaneously. Primary end points were area under the serum concentration-time curve from time 0 extrapolated to infinity (AUC inf ) and the maximum observed concentration (C max ). Secondary end points included safety and immunogenicity. AUC inf and C max were similar across the three groups. Geometrical mean ratio (GMR) of AUC inf was 1.11 between ABP 501 and adalimumab (USA), and 1.04 between ABP 501 and adalimumab (EU). GMR of C max was 1.04 between ABP 501 and adalimumab (USA) and 0.96 between ABP 501 and adalimumab (EU). The 90% CIs for the GMRs of AUC inf and C max were within the prespecified standard PK equivalence criteria of 0.80 to 1.25. Treatment-related adverse events were mild to moderate and were reported for 35.8%, 24.6% and 41.8% of subjects in the ABP 501, adalimumab (USA) and adalimumab (EU) groups; incidence of antidrug antibodies (ADAbs) was similar among the study groups. Results of this study demonstrated PK similarity of ABP 501 with adalimumab (USA) and adalimumab (EU) after a single 40-mg subcutaneous injection. No new safety signals with ABP 501 were identified. The safety and tolerability of ABP 501 was similar to the reference products, and similar ADAb rates were observed across the three groups. EudraCT number 2012-000785-37; Results. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://www.bmj.com/company/products-services/rights-and-licensing/.

  2. The Sort on Radioactive Waste Type model: A method to sort single-shell tanks into characteristic groups. Revision 1

    International Nuclear Information System (INIS)

    Hill, J.G.; Simpson, B.C.

    1994-08-01

    The Sort on Radioactive Waste Type (SORWT) model presents a method to categorize Hanford Site single-shell tanks (SSTs) into groups of tanks expected to exhibit similar chemical and physical characteristics based on their major waste types and processing histories. This model has identified 29 different waste-type groups encompassing 135 of the 149 SSTs and 93% of the total waste volume in SSTs. The remaining 14 SSTs and associated wastes could not be grouped according to the established criteria and were placed in an ungrouped category. This letter report will detail the assumptions and methodologies used to develop the SORWT model and present the grouping results. Included with this report is a brief description and approximate compositions of the single-shell tank waste types. In the near future, the validity of the predicted groups will be statistically tested using analysis of variance of characterization data obtained from recent (post-1989) core sampling and analysis activities. In addition, the SORWT model will be used to project the nominal waste characteristics of entire waste type groups that have some recent characterization data available. These subsequent activities will be documented along with these initial results in a comprehensive, formal PNL report cleared for public release by September 1994

  3. Earliest Deadline Control of a Group of Heat Pumps with a Single Energy Source

    NARCIS (Netherlands)

    Fink, J.; van Leeuwen, Richard Pieter

    2016-01-01

    In this paper, we develop and investigate the optimal control of a group of 104 heat pumps and a central Combined Heat and Power unit (CHP). The heat pumps supply space heating and domestic hot water to households. Each house has a buffer for domestic hot water and a floor heating system for space

  4. Analysis of single oil-bearing fluid inclusions in mid-Proterozoic sandstones (Roper Group, Australia)

    Science.gov (United States)

    Siljeström, Sandra; Volk, Herbert; George, Simon C.; Lausmaa, Jukka; Sjövall, Peter; Dutkiewicz, Adriana; Hode, Tomas

    2013-12-01

    Hydrocarbons and organic biomarkers extracted from black shales and other carbonaceous sedimentary rocks are valuable sources of information on the biodiversity and environment of early Earth. However, many Precambrian hydrocarbons including biomarkers are suspected of being younger contamination. An alternative approach is to study biomarkers trapped in oil-bearing fluid inclusions by bulk crushing samples and subsequently analysing the extracted hydrocarbons with gas chromatography-mass spectrometry. However, this method does not constrain the hydrocarbons to one particular oil inclusion, which means that if several different generations of oil inclusions are present in the sample, a mix of the content from these oil inclusions will be analysed. In addition, samples with few and/or small inclusions are often below the detection limit. Recently, we showed that it is possible to detect organic biomarkers in single oil-bearing fluid inclusions using time-of-flight secondary ion mass spectrometry (ToF-SIMS). In the present study, single fluid inclusion analysis has been performed on Proterozoic samples for the first time. Four individual oil-bearing fluid inclusions, found in 1430 Ma sandstone from the Roper Superbasin in Northern Australia, were analysed with ToF-SIMS. The ToF-SIMS spectra of the oil in the different inclusions are very similar to each other and are consistent with the presence of n-alkanes/branched alkanes, monocyclic alkanes, bicyclic alkanes, aromatic hydrocarbons, and tetracyclic and pentacyclic hydrocarbons. These results are in agreement with those obtained from bulk crushing of inclusions trapped in the same samples. The capability to analyse the hydrocarbon and biomarker composition of single oil-bearing fluid inclusions is a major breakthrough, as it opens up a way of obtaining molecular compositional data on ancient oils without the ambiguity of the origin of these hydrocarbons. Additionally, this finding suggests that it will be possible

  5. Meta-Analysis of Incremental Rehearsal Using Phi Coefficients to Compare Single-Case and Group Designs

    Science.gov (United States)

    Burns, Matthew K.; Zaslofsky, Anne F.; Kanive, Rebecca; Parker, David C.

    2012-01-01

    The current study meta-analyzed single-case design (SCD) and group research regarding incremental rehearsal (IR). We used phi to meta-analyze data from 19 IR studies. Data from the SCD studies resulted in a nonoverlap of all pairs (NAP) score of 98.9% (95% CI = 97.6-100%), which resulted in a weighted phi of 0.77 (95% CI = 0.69-0.83). The group…

  6. Synthesis of hydroxyl liquid polybutadiene by photochemical decomposition of hydrogen peroxide

    International Nuclear Information System (INIS)

    Moutinho, Marcus Tadeu Moura

    1995-01-01

    The synthesis of hydroxyl terminated polybutadienes (HTPB) by photochemical decomposition (λ=254 nm) of hydrogen peroxide (H 2 O 2 ) in alcoholic medium was studied. The influence of reaction time, H 2 O 2 and alcohol concentrations, type of alcohol and radiation intensity on the polymerization rate was determined. Higher polymerization rates were attained when t-butyl alcohol was used as the compatibilizing agent (19% conversion after 8 hours). The HTPBs were characterized by hydroxyl content (acetylation), functionality, IR microstructure and types of hydroxyl groups ( 1 H-NMR and 13 C-NMR), 2-vinyl cyclohexene (VCH) content and viscosity. The polymers showed molecular weights (Mn) in the range of 458 to 1,099, molecular weight distribution (Mw/Mn) in the range of 1.20 to 1.46 and functionality between 1.2 and 3.2 depending on the alcohol used. NMR results 1 H and 13 C) revealed low cis content for the polybutadienes and identified primary and secondary hydroxyl groups, depending on the alcohol employed as compatibilizing agent. The incorporation of alcohol in polymer chain ends was evidenced. The produced HTPBs presented viscosities in the range of 850 to 1,250 cP (at 25 deg C) and were VCH free. (author)

  7. Functional groups in a single pteridosperm species: Variability and circumscription (Pennsylvanian, Nova Scotia, Canada)

    Science.gov (United States)

    Zodrow, E.L.; Mastalerz, Maria

    2007-01-01

    Multiple foliar specimens of the Late Pennsylvanian fossil pteridosperm [gymnosperm] Alethopteris zeilleri (Ragot) Wagner were collected from one restricted stratigraphical horizon in the Canadian Sydney Coalfield. Variability of functional-group distribution using FTIR technique was studied in compressions, adaxial versus abaxial cuticles, and in unseparated cuticles as a function of maceration time from 48 to 168??h. The results obtained document spectral variability that could be expected within specimens of one species. For example, CH2/CH3 and Al/ox ratios can differ by as much as 20% of the values. Moreover, the experiments performed confirm that by using a previously established maceration protocol, long maceration periods do not bias FTIR spectra in terms of oxygenation overprinting. The inference that this cuticle is robust, under the given diagenetic level, probably reflects a reassuring degree of chemical fidelity of the Pennsylvanian plant to support Carboniferous chemotaxonomic observations. ?? 2006 Elsevier B.V. All rights reserved.

  8. Comparison between group and personal rehabilitation for dementia in a geriatric health service facility: single-blinded randomized controlled study.

    Science.gov (United States)

    Tanaka, Shigeya; Honda, Shin; Nakano, Hajime; Sato, Yuko; Araya, Kazufumi; Yamaguchi, Haruyasu

    2017-05-01

    The aim of this study was to compare the effects of rehabilitation involving group and personal sessions on demented participants. This single-blinded randomized controlled trial included 60 elderly participants with dementia in a geriatric health service facility, or R oken. Staff members, who did not participate in the intervention, examined cognitive function, mood, communication ability, severity of dementia, objective quality of life, vitality, and daily behaviour. After a baseline assessment, participants were randomly divided into three groups: (i) group intervention; (ii) personal intervention; and (iii) control. The 1-h group intervention (3-5 subjects) and 20-min personal intervention (one staff member per participant) were performed twice a week for 12 weeks (24 total sessions). The cognitive rehabilitation programme consisted of reminiscence, reality orientation, and physical exercise, and it was based on five principles of brain-activating rehabilitation; (i) pleasant atmosphere; (ii) communication; (iii) social roles; (iv) praising; and (v) errorless support. Data were analyzed after the second assessment. Outcome measures were analyzed in 43 participants-14 in the control group, 13 in group intervention, and 16 in personal intervention. Repeated measure ancova showed a significant interaction for cognitive function score (Mini-Mental State Examination) between group intervention and controls ( F  = 5.535, P = 0.029). In the post-hoc analysis, group intervention showed significant improvement (P = 0.016). Global severity of dementia tended to improve (P = 0.094) in group intervention compared to control (Mann-Whitney U -test). There were no significant interactions or improvements for other measurements. Group rehabilitation for dementia is more effective for improving cognitive function and global severity of dementia than personal rehabilitation in Roken. © 2016 Japanese Psychogeriatric Society.

  9. Earliest Deadline Control of a Group of Heat Pumps with a Single Energy Source

    Directory of Open Access Journals (Sweden)

    Jiří Fink

    2016-07-01

    Full Text Available In this paper, we develop and investigate the optimal control of a group of 104 heat pumps and a central Combined Heat and Power unit (CHP. The heat pumps supply space heating and domestic hot water to households. Each house has a buffer for domestic hot water and a floor heating system for space heating. Electricity for the heat pumps is generated by a central CHP unit, which also provides thermal energy to a district heating system. The paper reviews recent smart grid control approaches for central and distributed levels. An online algorithm is described based on the earliest deadline first theory that can be used on the aggregator level to control the CHP and to give signals to the heat pump controllers if they should start or should wait. The central controller requires only a limited amount of privacy-insensitive information from the heat pump controllers about their deadlines, which the heat pump controllers calculate for themselves by model predictions. In this way, a robust heat pump and CHP control is obtained, which is able to minimize energy demand and results in the desired thermal comfort for the households. The simulations demonstrate fast computation times due to minor computational and communication overheads.

  10. Effect of rb-bFGF eye drops and hydroxyl indican eye drops on tear film stability and dry eye symptoms after age-related cataract surgery

    Directory of Open Access Journals (Sweden)

    Jing Chen

    2017-10-01

    Full Text Available AIM: To compare and analyze the effect of recombinant bovine basic fibroblast growth factor(bFGFeye drops and hydroxyl indican eye drops on the tear film stability and dry eye symptoms after age-related cataract surgery. METHODS: A total of 115 patients(115 affected eyeswith dry eyes after age-related cataract surgery were divided into the bFGF group, the hydroxyl indican group and the blank control group by the random number table method. The blank control group was only given routine anti-inflammatory treatment, and on the basis, the bFGF group and the hydroxyl indican group were treated with bFGF eye drops and hydroxyl indican eye drops respectively. The clinical efficacy, adverse reactions, changes in scores of dry eye symptoms, Schirmer test(SⅠt, tear film break-up time(BUTand corneal fluorescein staining(CFSscores at different time points were compared among the three groups. RESULTS: The total markedly effective rates in the bFGF group(89.5%was higher than that in the hydroxyl indican group(70.3%or the blank control group(47.5%(PPPCONCLUSION: The tear film is unstable in early stage after age-related cataract surgery, and there are dry eye symptoms. The intervention with bFGF eye drops and hydroxyl indican eye drops can effectively restore the tear film stability and significantly relieve dry eye symptoms, and the effect of bFGF eye drops is more significant.

  11. The Sort on Radioactive Waste Type model: A method to sort single-shell tanks into characteristic groups

    International Nuclear Information System (INIS)

    Hill, J.G.; Simpson, B.C.

    1994-04-01

    The Sort on Radioactive Waste Type (SORWT) model presents a method to categorize Hanford Site single-shell tanks (SSTs) into groups of tank expected to exhibit similar chemical and physical characteristics based on their major waste types and processing histories. This model has identified 29 different waste-type groups encompassing 135 of the 149 SSTs and 93% of the total waste volume in SSTs. The remaining 14 SSTs and associated wastes could not be grouped according to the established criteria and were placed in an ungrouped category. This letter report will detail the assumptions and methodologies used to develop the SORWT model and present the grouping results. In the near future, the validity of the predicted groups will be statistically tested using analysis of variance of characterization data obtained from recent (post-1989) core sampling and analysis activities. In addition, the SORWT model will be used to project the nominal waste characteristics of entire waste type groups that have some recent characterization data available. These subsequent activities will be documented along with these initial results in a comprehensive, formal PNL report cleared for public release by September 1994

  12. Glutathione--hydroxyl radical interaction: a theoretical study on radical recognition process.

    Directory of Open Access Journals (Sweden)

    Béla Fiser

    Full Text Available Non-reactive, comparative (2 × 1.2 μs molecular dynamics simulations were carried out to characterize the interactions between glutathione (GSH, host molecule and hydroxyl radical (OH(•, guest molecule. From this analysis, two distinct steps were identified in the recognition process of hydroxyl radical by glutathione: catching and steering, based on the interactions between the host-guest molecules. Over 78% of all interactions are related to the catching mechanism via complex formation between anionic carboxyl groups and the OH radical, hence both terminal residues of GSH serve as recognition sites. The glycine residue has an additional role in the recognition of OH radical, namely the steering. The flexibility of the Gly residue enables the formation of further interactions of other parts of glutathione (e.g. thiol, α- and β-carbons with the lone electron pair of the hydroxyl radical. Moreover, quantum chemical calculations were carried out on selected GSH/OH(• complexes and on appropriate GSH conformers to describe the energy profile of the recognition process. The relative enthalpy and the free energy changes of the radical recognition of the strongest complexes varied from -42.4 to -27.8 kJ/mol and from -21.3 to 9.8 kJ/mol, respectively. These complexes, containing two or more intermolecular interactions, would be the starting configurations for the hydrogen atom migration to quench the hydroxyl radical via different reaction channels.

  13. Effects of partial hydrogenation, epoxidation, and hydroxylation on the fuel properties of fatty acid methyl esters

    Energy Technology Data Exchange (ETDEWEB)

    Wadumesthrige, Kapila; Salley, Steven O.; Ng, K.Y. Simon [Department of Chemical Engineering and Materials Science, Wayne State University, 5050 Anthony Wayne Drive, Detroit, MI 48202 (United States)

    2009-10-15

    The properties of biodiesel depend on the chemical structure of individual fatty acid methyl esters (FAME). In this work the chemical structure of fatty acid chains was modified by catalytic hydrogenation, epoxidation and hydroxylation under controlled conditions. Hydrolysis of ester functionality or oxidation of fatty acid chain was not observed during these reactions. The properties of hydrogenated FAME strongly depend on the hydrogenation time. The total saturated fatty acid (SFA) percentage increased from 29.3% to 76.2% after 2 h of hydrogenation. This hydrogenated FAME showed higher oxidation stability and higher cetane number but poor cold flow properties. Formation of trans FAME was observed during hydrogenation. Both hydroxylation and epoxidation resulted in a decrease of unsaturated fatty acid methyl ester (UFA) fraction. The percentages of total unsaturated FAME decreased 39% in the epoxidation reaction and 44% in the hydroxylation reaction. The addition of hydroxyl groups to the unsaturated regions of the fatty acid chain yields biodiesel with better cold flow properties, increased lubricity and slightly increased oxidative stability. However, epoxy FAME shows some interesting properties such as higher oxidation stability, higher cetane number and acceptable cold flow properties, which met the limits of ASTM D6751 biodiesel specifications. (author)

  14. The use of Lorentz group formalism in solving polarization effects of a birefringent single mode optical fiber

    International Nuclear Information System (INIS)

    Ishiekwene, G.C.; Brown, C.S.; Mensah, S.Y.; Bak, A.E.

    2000-07-01

    A theoretical analysis on the polarization effects of a light beam propagating in a birefringent single-mode fiber is presented. We derive a system of differential equations representing the evolution of Stokes parameters and illustrate their application to polarization effects in a straight birefringent single mode optical fiber. The solutions to the set of equations are obtained using specifically the methods of the unified formalism for polarization optics which adopt the use of the Stokes-Mueller equation and the Lorentz group to model polarization phenomena in media such as optical fibers. The analytical results presented using this approach are identical to results obtained from other conventional methods. We observe the characteristic exponential decrease in the total intensity of the input light due to attenuation by the fiber. (author)

  15. Impact of the Korean Diagnosis-Related Groups payment system on the outcomes of adenotonsillectomy: A single center experience.

    Science.gov (United States)

    Kwak, Sang Hyun; Kim, Ji Hoon; Kim, Da Hee; Kim, Jung Min; Byeon, Hyung Kwon; Kim, Won Shik; Koh, Yoon Woo; Kim, Se-Heon; Choi, Eun Chang

    2018-06-01

    To report outcomes with regard to clinical aspects and medical costs of adenotonsillectomy and tonsillectomy at a single institution before and after implementation of the Diagnosis-Related Groups (DRG) payment system in Korea. We retrospectively reviewed the records of patients treated with adenotonsillectomy or tonsillectomy between July 2012 and June 2014. The Korean DRG payment system was applied to seven groups of specific diseases and surgeries including adenotonsillectomy and tonsillectomy from July 2013 at all hospitals in Korea. We divided patients into four groups according whether the fee-for-service (FFS) or DRG payment system was implemented and operation type (FFS-adenotonsillectomy (AT), DRG-AT, FFS-tonsillectomy (T), and DRG-T). A total of 1402 patients were included (485 FFS-AT, 490 DRG-AT, 203 FFS-T, and 223 DRG-T). The total medical cost of the DRG-AT group was significantly lower than that of the FFS-AT group (1191±404 vs. 1110±279 USD, PDRG system for adenotonsillectomy and tonsillectomy reduced medical costs and clinical outcomes were not significantly altered by the adoption of the DRG system. 4. Copyright © 2017 Elsevier B.V. All rights reserved.

  16. The Sort on Radioactive Waste Type Model: A method to sort single-shell tanks into characteristics groups

    International Nuclear Information System (INIS)

    Hill, J.G.; Anderson, G.S.; Simpson, B.C.

    1995-02-01

    The Sort on Radioactive Waste Type (SORWT) Model is a method to categorize Hanford Site single-shell tanks (SSTS) into groups of tanks expected to exhibit similar chemical and physical characteristics based on their major waste types and processing histories. The model has identified 24 different waste-type groups encompassing 133 of the 149 SSTs and 93% of the total waste volume in SSTS. The remaining 16 SSTs and associated wastes could not be grouped. according to the established criteria and were placed in an ungrouped category. A detailed statistical verification study has been conducted that employs analysis of variance (ANOVA) and the core sample analysis data collected since 1989. These data cover eight tanks and five SORWT groups. The verification study showed that these five SORWT groups are highly statistically significant; they represent approximately 10% of the total waste volume and 26% of the total sludge volume in SSTS. Future sampling recommendations based on the SORWT Model results include 32 core samples from 16 tanks and 18 auger samples from six tanks. Combining these data with the existing body of information will form the basis for characterizing 98 SSTs (66%). These 98 SSTs represent 78% of the total waste volume, 61% of the total sludge volume, and 88 % of the salt cake volume

  17. Hydroxyl free radical production during torsional phacoemulsification.

    Science.gov (United States)

    Aust, Steven D; Hebdon, Thomas; Humbert, Jordan; Dimalanta, Ramon

    2010-12-01

    To quantitate free radical generation during phacoemulsification using an ultrasonic phacoemulsification device that includes a torsional mode and evaluate tip designs specific to the torsional mode. Chemistry and Biochemistry Department, Utah State University, Logan, Utah, USA. Experimental study. Experiments were performed using the Infiniti Vision System and OZil handpiece. Hydroxyl radical concentrations in the aspirated irrigation solution during torsional phacoemulsification were quantitated as nanomolar malondialdehyde (nM MDA) and determined spectrophotometrically using the deoxyribose assay. The mean free radical production during phacoemulsification with torsional modality at 100% amplitude was 30.1 nM MDA ± 5.1 (SD) using a 0.9 mm 45-degree Kelman tapered ABS tip. With other tip designs intended for use with the torsional modality, free radical production was further reduced when fitted with the 0.9 mm 45-degree Kelman mini-flared ABS tip (13.2 ± 5.6 nM MDA) or the 0.9 mm 45-degree OZil-12 mini-flared ABS tip (14.3 ± 6.7 nM MDA). Although the measurements resulting from the use of the latter 2 tips were not statistically significantly different (P ≈ .25), they were different from those of the tapered tip (P<.0001). The MDA concentration in the aspirated irrigation solution using the torsional modality was approximately one half that reported for the handpiece's longitudinal modality in a previous study using the same bent-tip design (Kelman tapered, P<.0001). The level of MDA was further reduced approximately one half with torsional-specific tips. Copyright © 2010 ASCRS and ESCRS. Published by Elsevier Inc. All rights reserved.

  18. Regioselective alkane hydroxylation with a mutant AlkB enzyme

    Science.gov (United States)

    Koch, Daniel J.; Arnold, Frances H.

    2012-11-13

    AlkB from Pseudomonas putida was engineered using in-vivo directed evolution to hydroxylate small chain alkanes. Mutant AlkB-BMO1 hydroxylates propane and butane at the terminal carbon at a rate greater than the wild-type to form 1-propanol and 1-butanol, respectively. Mutant AlkB-BMO2 similarly hydroxylates propane and butane at the terminal carbon at a rate greater than the wild-type to form 1-propanol and 1-butanol, respectively. These biocatalysts are highly active for small chain alkane substrates and their regioselectivity is retained in whole-cell biotransformations.

  19. An examination of variations in the cepstral spectral index of dysphonia across a single breath group in connected speech.

    Science.gov (United States)

    Watts, Christopher R; Awan, Shaheen N

    2015-01-01

    The purpose of this study was to use spectral and cepstral analyses of speech to investigate whether underlying physiological changes in voice result in changes in acoustic estimates of dysphonia severity in continuous speech contexts within a single breath group. The effect of dysphonia on acoustic estimates of dysphonia severity, frequency, relative intensity, and vocalization time across initial and terminal segments of a single breath group using a common clinical stimulus was investigated. Prospective quasi-experimental controlled design. Digitized recordings of the Consensus Auditory-Perceptual Evaluation of Voice sentence "We were away a year ago" were obtained from 20 treatment-seeking dysphonic individuals (females, mean age = 39 years) and 20 normal controls (females, mean age = 39 years). Each recorded sample was separated into the first four syllables ("We were away … ") and second four syllables ("…a year ago.") of the breath group. Cepstral and spectral measures, intensity measures, and temporal analyses were obtained and used in calculations of the Cepstral Spectral Index of Dysphonia (CSID, an acoustic estimate of dysphonia severity), fundamental frequency (F0), vocalization time, and relative vocal intensity (dB SLP). Statistical analyses were applied to calculations of change (delta [Δ]) in these measures from one breath group segment to the next. Results revealed a significant effect of group on measures of CSID and F0, but not relative intensity or vocalization time. Dysphonic speakers exhibited a significant increase in the CSID from the first to second breath group segment and limited variation in F0 compared with controls. These results may support the hypothesis that voice impairment increases in severity toward the termination of a breath group even within a short temporal frame (i.e., 2 seconds or less of connected speech), and that this portion of the breath group may be an important determinant of perceptual impressions. Further

  20. Vacuum ultraviolet photoionization cross section of the hydroxyl radical

    Science.gov (United States)

    Dodson, Leah G.; Savee, John D.; Gozem, Samer; Shen, Linhan; Krylov, Anna I.; Taatjes, Craig A.; Osborn, David L.; Okumura, Mitchio

    2018-05-01

    The absolute photoionization spectrum of the hydroxyl (OH) radical from 12.513 to 14.213 eV was measured by multiplexed photoionization mass spectrometry with time-resolved radical kinetics. Tunable vacuum ultraviolet (VUV) synchrotron radiation was generated at the Advanced Light Source. OH radicals were generated from the reaction of O(1D) + H2O in a flow reactor in He at 8 Torr. The initial O(1D) concentration, where the atom was formed by pulsed laser photolysis of ozone, was determined from the measured depletion of a known concentration of ozone. Concentrations of OH and O(3P) were obtained by fitting observed time traces with a kinetics model constructed with literature rate coefficients. The absolute cross section of OH was determined to be σ(13.436 eV) = 3.2 ± 1.0 Mb and σ(14.193 eV) = 4.7 ± 1.6 Mb relative to the known cross section for O(3P) at 14.193 eV. The absolute photoionization spectrum was obtained by recording a spectrum at a resolution of 8 meV (50 meV steps) and scaling to the single-energy cross sections. We computed the absolute VUV photoionization spectrum of OH and O(3P) using equation-of-motion coupled-cluster Dyson orbitals and a Coulomb photoelectron wave function and found good agreement with the observed absolute photoionization spectra.

  1. Vacuum ultraviolet photoionization cross section of the hydroxyl radical.

    Science.gov (United States)

    Dodson, Leah G; Savee, John D; Gozem, Samer; Shen, Linhan; Krylov, Anna I; Taatjes, Craig A; Osborn, David L; Okumura, Mitchio

    2018-05-14

    The absolute photoionization spectrum of the hydroxyl (OH) radical from 12.513 to 14.213 eV was measured by multiplexed photoionization mass spectrometry with time-resolved radical kinetics. Tunable vacuum ultraviolet (VUV) synchrotron radiation was generated at the Advanced Light Source. OH radicals were generated from the reaction of O( 1 D) + H 2 O in a flow reactor in He at 8 Torr. The initial O( 1 D) concentration, where the atom was formed by pulsed laser photolysis of ozone, was determined from the measured depletion of a known concentration of ozone. Concentrations of OH and O( 3 P) were obtained by fitting observed time traces with a kinetics model constructed with literature rate coefficients. The absolute cross section of OH was determined to be σ(13.436 eV) = 3.2 ± 1.0 Mb and σ(14.193 eV) = 4.7 ± 1.6 Mb relative to the known cross section for O( 3 P) at 14.193 eV. The absolute photoionization spectrum was obtained by recording a spectrum at a resolution of 8 meV (50 meV steps) and scaling to the single-energy cross sections. We computed the absolute VUV photoionization spectrum of OH and O( 3 P) using equation-of-motion coupled-cluster Dyson orbitals and a Coulomb photoelectron wave function and found good agreement with the observed absolute photoionization spectra.

  2. Cooperation between bound waters and hydroxyls in controlling isotope-exchange rates

    Science.gov (United States)

    Panasci, Adele F.; McAlpin, J. Gregory; Ohlin, C. André; Christensen, Shauna; Fettinger, James C.; Britt, R. David; Rustad, James R.; Casey, William H.

    2012-02-01

    Mineral oxides differ from aqueous ions in that the bound water molecules are usually attached to different metal centers, or vicinal, and thus separated from one another. In contrast, for most monomeric ions used to establish kinetic reactivity trends, such as octahedral aquo ions (e.g., Al(H 2O) 63+), the bound waters are closely packed, or geminal. Because of this structural difference, the existing literature about ligand substitution in monomer ions may be a poor guide to the reactions of geochemical interest. To understand how coordination of the reactive functional groups might affect the rates of simple water-exchange reactions, we synthesized two structurally similar Rh(III) complexes, [Rh(phen) 2(H 2O) 2] 3+ [ 1] and [Rh(phen) 2(H 2O)Cl] 2+ [ 2] where (phen) = 1,10-phenanthroline. Complex [ 1] has two adjacent, geminal, bound waters in the inner-coordination sphere and [ 2] has a single bound water adjacent to a bound chloride ion. We employed Rh(III) as a trivalent metal rather than a more geochemically relevant metal like Fe(III) or Al(III) to slow the rate of reaction, which makes possible measurement of the rates of isotopic substitution by simple mass spectrometry. We prepared isotopically pure versions of the molecules, dissolved them into isotopically dissimilar water, and measured the rates of exchange from the extents of 18O and 16O exchange at the bound waters. The pH dependency of rates differ enormously between the two complexes. Pseudo-first-order rate coefficients at 298 K for water exchanges from the fully protonated molecules are close: k0298 = 5 × 10 -8(±0.5 × 10 -8) s -1 for [ 1] and k0298 = 2.5 × 10 -9(±1 × 10 -9) for [ 2]. Enthalpy and entropy activation parameters (Δ H‡ and Δ S‡) were measured to be 119(±3) kJ mol -1, and 14(±1) J mol -1 K -1, respectively for [ 1]. The corresponding parameters for the mono-aquo complex, [ 2], are 132(±3) kJ mol -1 and 41.5(±2) J mol -1 K -1. Rates increase by many orders of magnitude

  3. Comparing a single case to a control group - Applying linear mixed effects models to repeated measures data.

    Science.gov (United States)

    Huber, Stefan; Klein, Elise; Moeller, Korbinian; Willmes, Klaus

    2015-10-01

    In neuropsychological research, single-cases are often compared with a small control sample. Crawford and colleagues developed inferential methods (i.e., the modified t-test) for such a research design. In the present article, we suggest an extension of the methods of Crawford and colleagues employing linear mixed models (LMM). We first show that a t-test for the significance of a dummy coded predictor variable in a linear regression is equivalent to the modified t-test of Crawford and colleagues. As an extension to this idea, we then generalized the modified t-test to repeated measures data by using LMMs to compare the performance difference in two conditions observed in a single participant to that of a small control group. The performance of LMMs regarding Type I error rates and statistical power were tested based on Monte-Carlo simulations. We found that starting with about 15-20 participants in the control sample Type I error rates were close to the nominal Type I error rate using the Satterthwaite approximation for the degrees of freedom. Moreover, statistical power was acceptable. Therefore, we conclude that LMMs can be applied successfully to statistically evaluate performance differences between a single-case and a control sample. Copyright © 2015 Elsevier Ltd. All rights reserved.

  4. Velocities of dislocation groups in very thin neutron-irradiated copper single crystals measured by slip line cinematography

    Energy Technology Data Exchange (ETDEWEB)

    Potthoff, H.H. (Technische Univ. Braunschweig (Germany, F.R.). Inst. fuer Metallphysik und Nukleare Festkoerperphysik)

    1983-05-16

    Slip line development on very thin flat single crystals of neutron-irradiated Cu (thickness down to only 15 to 20 ..mu..m, orientation for single glide, yield region, room temperature) is recorded by high-speed cinematography during tensile deformation. In such very thin crystals glide dislocations on the slip plane must be arranged in a rather simple way. Drops in tensile load occuring during initiation of single slip lines at the Lueders band front indicate that in the beginning of a slip line development dislocation groups traverse the whole glide plane in very short times. Evaluating the data measured for the slip line growth v/sub s/ >= 10 cm/s is found for screw dislocations and v/sub e/ >= v/sub s/ for edge dislocations. For later stages on thin crystals and for all stages on thick crystals (>= several 100 ..mu..m) slip line development is much slower and slip line show many cross slip events which then appear to control the mean velocity of the dislocations.

  5. Velocities of dislocation groups in very thin neutron-irradiated copper single crystals measured by slip line cinematography

    International Nuclear Information System (INIS)

    Potthoff, H.H.

    1983-01-01

    Slip line development on very thin flat single crystals of neutron-irradiated Cu (thickness down to only 15 to 20 μm, orientation for single glide, yield region, room temperature) is recorded by high-speed cinematography during tensile deformation. In such very thin crystals glide dislocations on the slip plane must be arranged in a rather simple way. Drops in tensile load occuring during initiation of single slip lines at the Lueders band front indicate that in the beginning of a slip line development dislocation groups traverse the whole glide plane in very short times. Evaluating the data measured for the slip line growth v/sub s/ >= 10 cm/s is found for screw dislocations and v/sub e/ >= v/sub s/ for edge dislocations. For later stages on thin crystals and for all stages on thick crystals (>= several 100 μm) slip line development is much slower and slip line show many cross slip events which then appear to control the mean velocity of the dislocations. (author)

  6. The effect of hydroxylation on CNT to form Chitosan-CNT composites: A DFT study

    International Nuclear Information System (INIS)

    Yu, Rui; Ran, Maofei; Wen, Jie; Sun, Wenjing; Chu, Wei; Jiang, Chengfa; He, Zhiwei

    2015-01-01

    Graphical abstract: - Highlights: • The effect of hydroxylation on CNT to form Chitosan-CNT composites was studied. • The adsorption of Chitosan on CNTs is very weak by electrostatic interactions. • Chitosan loads onto CNT-OH_n via hydrogen-bond interactions. • Chitosan transfers electron to CNT-OH_n and thus improves the reactivity of CNT. - Abstract: The effect of types of CNTs (pristine and hydroxylated) on the synthesis of Chitosan-CNT (CS-CNT) composites was investigated theoretically. The adsorption energy (E_a_d_s) of CS on the pristine CNT and hydroxylated CNTs (CNT-OH_n, n = 1–6) as well as the structural and electronic properties of said composites have been investigated. Results show that the adsorption of CS on CNT and CNT-OH_n is thermodynamically favored. The E_a_d_s of CS on CNTs was calculated to be −20.387 kcal/mol from electrostatic interactions. For CS adsorbed into CNT-OH_n, E_a_d_s ranges from −20.612 to −37.567 kcal/mol. Hydroxyl groups on CNT are the main adsorption sites for CS loading onto CNT-OH_n via hydrogen-bond interactions. The CS-CNT-OH_3 is the most sable composite among tested complexes. The energy gap (ΔE_g_a_p) of CS-CNT-OH_3 was calculated less than pristine CNT and CNT-OH_3, indicative of the composites being more reactive than that of pristine CNTs and CNT-OH_3. It was proved that CS can transfer electron to the hydroxylated CNTs, thus overcoming the drawbacks of CNTs being chemically inert.

  7. The effect of hydroxylation on CNT to form Chitosan-CNT composites: A DFT study

    Energy Technology Data Exchange (ETDEWEB)

    Yu, Rui [China-America Cancer Research Institute, Key Laboratory for Medical Molecular Diagnostics of Guangdong Province, Guangdong Medical University, Dongguan, Guangdong 523808 (China); Department of Chemical Engineering, Sichuan University, Chengdu 610065 (China); Ran, Maofei [College of Chemistry & Environment Protection Engineering, Southwest University for Nationalities, Chengdu 610041, Sichuan (China); Wen, Jie [College of Chemistry and Chemical Engineering, Southwest Petroleum University, Chengdu 610500, Sichuan (China); Sun, Wenjing, E-mail: swj_gdmc@163.com [China-America Cancer Research Institute, Key Laboratory for Medical Molecular Diagnostics of Guangdong Province, Guangdong Medical University, Dongguan, Guangdong 523808 (China); Chu, Wei; Jiang, Chengfa [Department of Chemical Engineering, Sichuan University, Chengdu 610065 (China); He, Zhiwei, E-mail: zhiweihe688@yahoo.com [China-America Cancer Research Institute, Key Laboratory for Medical Molecular Diagnostics of Guangdong Province, Guangdong Medical University, Dongguan, Guangdong 523808 (China)

    2015-12-30

    Graphical abstract: - Highlights: • The effect of hydroxylation on CNT to form Chitosan-CNT composites was studied. • The adsorption of Chitosan on CNTs is very weak by electrostatic interactions. • Chitosan loads onto CNT-OH{sub n} via hydrogen-bond interactions. • Chitosan transfers electron to CNT-OH{sub n} and thus improves the reactivity of CNT. - Abstract: The effect of types of CNTs (pristine and hydroxylated) on the synthesis of Chitosan-CNT (CS-CNT) composites was investigated theoretically. The adsorption energy (E{sub ads}) of CS on the pristine CNT and hydroxylated CNTs (CNT-OH{sub n}, n = 1–6) as well as the structural and electronic properties of said composites have been investigated. Results show that the adsorption of CS on CNT and CNT-OH{sub n} is thermodynamically favored. The E{sub ads} of CS on CNTs was calculated to be −20.387 kcal/mol from electrostatic interactions. For CS adsorbed into CNT-OH{sub n}, E{sub ads} ranges from −20.612 to −37.567 kcal/mol. Hydroxyl groups on CNT are the main adsorption sites for CS loading onto CNT-OH{sub n} via hydrogen-bond interactions. The CS-CNT-OH{sub 3} is the most sable composite among tested complexes. The energy gap (ΔE{sub gap}) of CS-CNT-OH{sub 3} was calculated less than pristine CNT and CNT-OH{sub 3}, indicative of the composites being more reactive than that of pristine CNTs and CNT-OH{sub 3}. It was proved that CS can transfer electron to the hydroxylated CNTs, thus overcoming the drawbacks of CNTs being chemically inert.

  8. Hydroxyl radical production in plasma electrolysis with KOH electrolyte solution

    Energy Technology Data Exchange (ETDEWEB)

    Saksono, Nelson; Febiyanti, Irine Ayu, E-mail: irine.ayu41@ui.ac.id; Utami, Nissa; Ibrahim [Department of Chemical Engineering, Universitas Indonesia, Depok 16424, Indonesia Phone: +62217863516, Fax: +62217863515 (Indonesia)

    2015-12-29

    Plasma electrolysis is an effective technology for producing hydroxyl radical (•OH). This method can be used for waste degradation process. This study was conducted to obtain the influence of applied voltage, electrolyte concentration, and anode depth in the plasma electrolysis system for producing hydroxyl radical. The materials of anode and cathode, respectively, were made from tungsten and stainless steel. KOH solution was used as the solution. Determination of hydroxyl radical production was done by measuring H{sub 2}O{sub 2} amount formed in plasma system using an iodometric titration method, while the electrical energy consumed was obtained by measuring the electrical current throughout the process. The highest hydroxyl radical production was 3.51 mmol reached with 237 kJ energy consumption in the power supply voltage 600 V, 0.02 M KOH, and 0.5 cm depth of anode.

  9. Effect of curcumin against oxidation of biomolecules by hydroxyl radicals.

    Science.gov (United States)

    Borra, Sai Krishna; Mahendra, Jaideep; Gurumurthy, Prema; Jayamathi; Iqbal, Shabeer S; Mahendra, Little

    2014-10-01

    Among various reactive oxygen species, hydroxyl radicals have the strongest chemical activity, which can damage a wide range of essential biomolecules such as lipids, proteins, and DNA. The objective of this study was to investigate the beneficial effects of curcumin on prevention of oxidative damage of biomolecules by hydroxyl radicals generated in in vitro by a Fenton like reaction. We have incubated the serum, plasma and whole blood with H2O2/Cu2+/ Ascorbic acid system for 4 hours at 37 0C and observed the oxidation of biomolecules like albumin, lipids, proteins and DNA. Curcumin at the concentrations of 50,100 and 200 μmoles, prevented the formation of ischemia modified albumin, MDA, protein carbonyls, oxidized DNA and increased the total antioxidant levels and GSH significantly. These observations suggest the hydroxyl radical scavenging potentials of curcumin and protective actions to prevent the oxidation of biomolecules by hydroxyl radicals.

  10. Hydroxylation of p-substituted phenols by tyrosinase: Further insight into the mechanism of tyrosinase activity

    Energy Technology Data Exchange (ETDEWEB)

    Munoz-Munoz, Jose Luis [GENZ - Grupo de Investigacion Enzimologia, Departamento de Bioquimica y Biologia Molecular-A, Facultad de Biologia, Campus Internacional de Excelencia Campus Mare Nostrum, Universidad de Murcia, E-30100 Espinardo, Murcia (Spain); Berna, Jose [Grupo de Quimica Organica Sintetica, Departamento de Quimica Organica, Facultad de Quimica Campus Internacional de Excelencia Campus Mare Nostrum, Universidad de Murcia (Spain); Garcia-Molina, Maria del Mar; Garcia-Molina, Francisco [GENZ - Grupo de Investigacion Enzimologia, Departamento de Bioquimica y Biologia Molecular-A, Facultad de Biologia, Campus Internacional de Excelencia Campus Mare Nostrum, Universidad de Murcia, E-30100 Espinardo, Murcia (Spain); Garcia-Ruiz, Pedro Antonio [QCPAI - Grupo de Quimica de Carbohidratos, Polimeros y Aditivos Industriales, Departamento de Quimica Organica, Facultad de Quimica Campus Internacional de Excelencia Campus Mare Nostrum, Universidad de Murcia (Spain); Varon, Ramon [Departamento de Quimica-Fisica, Escuela de Ingenieros Industriales de Albacete, Universidad de Castilla la Mancha, Avda. Espana s/n. Campus Universitario, E-02071 Albacete (Spain); and others

    2012-07-27

    Highlights: Black-Right-Pointing-Pointer The action the copper complexes and tyrosinase on phenols is equivalent. Black-Right-Pointing-Pointer Isotope effect showed that nucleophilic attack to copper atom may be the slower step. Black-Right-Pointing-Pointer The value of {rho} (Hammett constant) supports an electrophilic aromatic substitution. Black-Right-Pointing-Pointer Data obtained in steady state pH 7 conditions support the mechanism of Scheme 1SM. -- Abstract: A study of the monophenolase activity of tyrosinase by measuring the steady state rate with a group of p-substituted monophenols provides the following kinetic information: k{sub cat}{sup m} and the Michaelis constant, K{sub M}{sup m}. Analysis of these data taking into account chemical shifts of the carbon atom supporting the hydroxyl group ({delta}) and {sigma}{sub p}{sup +}, enables a mechanism to be proposed for the transformation of monophenols into o-diphenols, in which the first step is a nucleophilic attack on the copper atom on the form E{sub ox} (attack of the oxygen of the hydroxyl group of C-1 on the copper atom) followed by an electrophilic attack (attack of the hydroperoxide group on the ortho position with respect to the hydroxyl group of the benzene ring, electrophilic aromatic substitution with a reaction constant {rho} of -1.75). These steps show the same dependency on the electronic effect of the substituent groups in C-4. Furthermore, a study of a solvent deuterium isotope effect on the oxidation of monophenols by tyrosinase points to an appreciable isotopic effect. In a proton inventory study with a series of p-substituted phenols, the representation of k{sub cat}{sup f{sub n}}/k{sub cat}{sup f{sub 0}} against n (atom fractions of deuterium), where k{sub cat}{sup f{sub n}} is the catalytic constant for a molar fraction of deuterium (n) and k{sub cat}{sup f{sub 0}} is the corresponding kinetic parameter in a water solution, was linear for all substrates. These results indicate that

  11. Hydroxylation of p-substituted phenols by tyrosinase: Further insight into the mechanism of tyrosinase activity

    International Nuclear Information System (INIS)

    Muñoz-Muñoz, Jose Luis; Berna, Jose; García-Molina, María del Mar; Garcia-Molina, Francisco; Garcia-Ruiz, Pedro Antonio; Varon, Ramon

    2012-01-01

    Highlights: ► The action the copper complexes and tyrosinase on phenols is equivalent. ► Isotope effect showed that nucleophilic attack to copper atom may be the slower step. ► The value of ρ (Hammett constant) supports an electrophilic aromatic substitution. ► Data obtained in steady state pH 7 conditions support the mechanism of Scheme 1SM. -- Abstract: A study of the monophenolase activity of tyrosinase by measuring the steady state rate with a group of p-substituted monophenols provides the following kinetic information: k cat m and the Michaelis constant, K M m . Analysis of these data taking into account chemical shifts of the carbon atom supporting the hydroxyl group (δ) and σ p + , enables a mechanism to be proposed for the transformation of monophenols into o-diphenols, in which the first step is a nucleophilic attack on the copper atom on the form E ox (attack of the oxygen of the hydroxyl group of C-1 on the copper atom) followed by an electrophilic attack (attack of the hydroperoxide group on the ortho position with respect to the hydroxyl group of the benzene ring, electrophilic aromatic substitution with a reaction constant ρ of −1.75). These steps show the same dependency on the electronic effect of the substituent groups in C-4. Furthermore, a study of a solvent deuterium isotope effect on the oxidation of monophenols by tyrosinase points to an appreciable isotopic effect. In a proton inventory study with a series of p-substituted phenols, the representation of k cat f n /k cat f 0 against n (atom fractions of deuterium), where k cat f n is the catalytic constant for a molar fraction of deuterium (n) and k cat f 0 is the corresponding kinetic parameter in a water solution, was linear for all substrates. These results indicate that only one of the proton transfer processes from the hydroxyl groups involved the catalytic cycle is responsible for the isotope effects. We suggest that this step is the proton transfer from the hydroxyl group

  12. Quantum Chemical Study on the Antioxidation Mechanism of Piceatannol and Isorhapontigenin toward Hydroxyl and Hydroperoxyl Radicals.

    Directory of Open Access Journals (Sweden)

    Yang Lu

    Full Text Available A systematic study of the antioxidation mechanisms behind hydroxyl (•OH and hydroperoxyl (•OOH radical scavenging activity of piceatannol (PIC and isorhapontigenin (ISO was carried out using density functional theory (DFT method. Two reaction mechanisms, abstraction (ABS and radical adduct formation (RAF, were discussed. A total of 24 reaction pathways of scavenging •OH and •OOH with PIC and ISO were investigated in the gas phase and solution. The thermodynamic and kinetic properties of all pathways were calculated. Based on these results, we evaluated the antioxidant activity of every active site of PIC and ISO and compared the abilities of PIC and ISO to scavenge radicals. According to our results, PIC and ISO may act as effective •OH and •OOH scavengers in organism. A4-hydroxyl group is a very important active site for PIC and ISO to scavenge radicals. The introducing of -OH or -OCH3 group to the ortho-position of A4-hydroxyl group would increase its antioxidant activity. Meanwhile, the conformational effect was researched, the results suggest that the presence and pattern of intramolecular hydrogen bond (IHB are considerable in determining the antioxidant activity of PIC and ISO.

  13. Synthesis and gas transport properties of hydroxyl-functionalized polyimides with intrinsic microporosity

    KAUST Repository

    Ma, Xiaohua

    2012-05-08

    A newly designed diamine monomer, 3,3,3′,3′-tetramethyl-1, 1′-spirobisindane-5,5′-diamino-6,6′-diol, was successfully used to synthesize two types of polyimides for membrane-based gas separation applications. The novel polymers integrate significant microporosity and polar hydroxyl groups, showing the combined features of polymers of intrinsic microporosity (PIMs) and functional polyimides (PIs). They possess high thermal stability, good solubility, and easy processability for membrane fabrication; the resulting membranes exhibit good permeability owing to the intrinsic microporosity introduced by the highly contorted PIM segments as well as high CO 2/CH 4 selectivity that arises from the hydroxyl groups. The membranes show CO 2/CH 4 selectivities of >20 when tested with a 1:1 CO 2/CH 4 mixture for feed pressures up to 50 bar. In addition, the incorporation of hydroxyl groups and microporosity in the polymers enhances their affinity to water, leading to remarkable water sorption capacities of up to 22 wt % at 35 °C and 95% relative humidity. © 2012 American Chemical Society.

  14. Apoptosis of THP-1 derived macrophages induced by sonodynamic therapy using a new sonosensitizer hydroxyl acetylated curcumin.

    Directory of Open Access Journals (Sweden)

    Longbin Zheng

    Full Text Available Curcumin is extracted from the rhizomes of the traditional Chinese herb Curcuma longa. Our previous study indicated curcumin was able to function as a sonosensitizer. Hydroxyl acylated curcumin was synthesized from curcumin to eliminate the unstable hydroxy perssad in our group. The potential use of Hydroxyl acylated curcumin as a sonosensitizer for sonodynamic therapy (SDT requires further exploration. This study investigated the sonodynamic effect of Hydroxyl acylated curcumin on THP-1 macrophage. THP-1 macrophages were cultured with Hydroxyl acylated curcumin at a concentration of 5.0 μg/mL for 4 hours and then exposed to pulse ultrasound irradiation (0.5 W/cm2 with 1.0 MHz for 5 min, 10 min and 15 min. Six hours later, cell viability decreased significantly by CCK-8 assay. After ultrasound irradiation, the ratio of apoptosis and necrosis in SDT group was higher than that in control, Hydroxyl acylated curcumin alone and ultrasound alone. Moreover, the apoptotic rate was higher than necrotic rate with the flow cytometry analysis. Furthermore, Hydroxyl acylated curcumin-SDT induced reactive oxygen species (ROS generation in THP-1 macrophages immediately after the ultrasound treatment while ROS generation was reduced significantly with the scavenger of singlet oxygen Sodium azide (NaN3. Hydroxyl acylated curcumin-SDT led to a conspicuous loss of mitochondrial membrane potential (MMP compared with other groups, while MMP was increased significantly with the scavenger of singlet oxygen Sodium azide (NaN3, ROS inhibitor N-acetyl cysteine (NAC and Mitochondrial Permeability Transition Pore (MPTP inhibitor Cyclosporin A (CsA. The cytochrome C, cleaved-Caspase-9, cleaved-Caspase-3 and cleaved-PARP upregulated after SDT through Western blotting. These findings suggested that Hydroxyl acylated curcumin under low-intensity ultrasound had sonodynamic effect on THP-1 macrophages via generation of intracellular singlet oxygen and mitochondria

  15. Oxygenated organic functional groups and their sources in single and submicron organic particles in MILAGRO 2006 campaign

    Directory of Open Access Journals (Sweden)

    S. Liu

    2009-09-01

    Full Text Available Fourier Transform Infrared (FTIR and X-ray Fluorescence (XRF were used to measure organic functional groups and elements of submicron particles collected during MILAGRO in March 2006 on three platforms: the Mexico City urban area (SIMAT, the high altitude site at 4010 m (Altzomoni, and the NCAR C130 aircraft. Scanning Transmission X-ray Microscopy (STXM and Near-Edge X-ray Absorption Fine Structure (NEXAFS were applied to single particle organic functional group abundance analysis of particles simultaneously collected at SIMAT and C130. Correlations of elemental concentrations showed different groups of source-related elements at SIMAT, Altzomoni, and C130, suggesting different processes affecting the air masses sampled at the three platforms. Cluster analysis resulted in seven distinct clusters of FTIR spectra, with the last three clusters consisting of spectra collected almost exclusively on the C130 platform, reflecting the variety of sources contributing to C130 samples. Positive Matrix Factorization (PMF of STXM-NEXAFS spectra identified three main factors representing soot, secondary, and biomass burning type spectra. PMF of FTIR spectra resulted in two fossil fuel combustion factors and one biomass burning factor, the former representative of source regions to the northeast and southwest of SIMAT. Alkane, carboxylic acid, amine, and alcohol functional groups were mainly associated with combustion related sources, while non-acid carbonyl groups were likely from biomass burning events. The majority of OM and O/C was attributed to combustion sources, although no distinction between direct emissions and atmospherically processed OM could be identified.

  16. Cytochrome P450-dependent N-hydroxylation of an aminoguanidine (amidinohydrazone) and microsomal retroreduction of the N-hydroxylated product.

    Science.gov (United States)

    Clement, B; Schultze-Mosgau, M H; Richter, P H; Besch, A

    1994-07-01

    1. The first example of a P450-dependent N-hydroxylation of an aminoguanidine (amidinohydrazone) is reported for 2-amino-5-chlorobenzophenone amidinohydrazone 1 (G 256) as substrate. 2. The N-hydroxylated metabolite 2 (2-amino-5-chlorobenzophenone N-hydroxyamidinohydrazone NOH-G256) and a further metabolite of 1, the phenol 3, were identified by tlc and ms analysis. 3. The microsomal reduction of an N-hydroxyaminoguanidine (N-hydroxy-amidino-hydrazone) was also demonstrated for the transformation of 2 to 1. 4. Both the N-hydroxylation of the aminoguanidine and the retroreduction of the N-hydroxyaminoguanidine were characterized by quantitative hplc analysis. 5. The conversion of the aminoguanidine 1 to N-hydroxyaminoguanidine 2 may be considered as an analogue of the physiological N-hydroxylation of arginine to N-hydroxyarginine by NO synthases.

  17. Hydroxylated PCBs in abiotic environmental matrices. Precipitation and surface waters

    Energy Technology Data Exchange (ETDEWEB)

    Darling, C.; Alaee, M.; Campbell, L.; Pacepavicius, G.; Ueno, D.; Muir, D. [National Water Research Institute, Burlington, ON (Canada)

    2004-09-15

    Hydroxylated PCBs (OH-PCBs) are of great interest environmentally because of their potential thyroidogenic effects. OH-PCBs can compete with thyroxine for binding sites on transthyretin, one of the three main thyroid hormone transport proteins in mammals1. The chemical structures of some OH-PCBs with a para OH group and adjacent chlorine atoms, particularly 4-OH-CB109, 4- OH-CB146, and 4-OH-CB187, share a similar structure to the thyroid hormones (T3 and T4), which have a para OH with adjacent iodine atoms. A number of OH-PCBs have been identified in the blood of humans and biota during the last 5 to 10 years, however, reports on the identity, presence and levels of OH-PCBs are limited. This presentation describes preliminary studies on the presence of OH-PCBs in abiotic samples and comparisons of congener patterns with biological samples. We have previously shown that OHPCBs were present in lake trout from the Great Lakes and nearby large lakes as well as in nearshore environments. We hypothesized that some of the OH-PCB present in fish might be from abiotic formation in water or the atmosphere, or from microbial oxidation of PCBs and/or deconjugation of PCB metabolites in waste treatment plants.

  18. Development and evaluation of a modified brief assertiveness training for nurses in the workplace: a single-group feasibility study.

    Science.gov (United States)

    Nakamura, Yohei; Yoshinaga, Naoki; Tanoue, Hiroki; Kato, Sayaka; Nakamura, Sayoko; Aoishi, Keiko; Shiraishi, Yuko

    2017-01-01

    Effective communication has a great impact on nurses' job satisfaction, team relationships, as well as patient care/safety. Previous studies have highlighted the various beneficial effects of enhancing communication through assertiveness training programs for nurses. However, most programs take a long time to implement; thus, briefer programs are urgently required for universal on-the-job-training in the workplace. The purpose of this feasibility study was to develop and evaluate a modified brief assertiveness training program (with cognitive techniques) for nurses in the workplace. This study was carried out as a single-group, open trial (pre-post comparison without a control group). Registered nurses and assistant nurses, working at two private psychiatric hospitals in Miyazaki Prefecture in Japan, were recruited. After enrolling in the study, participants received a program of two 90-min sessions with a 1-month interval between sessions. The primary outcome was the Rathus Assertiveness Schedule (RAS), with secondary measurements using the Brief Version of the Fear of Negative Evaluation Scale (BFNE) and the Brief Job Stress Questionnaire (BJSQ). Assessments were conducted at baseline and after a 1-month interval (pre- and post-intervention). A total of 22 participants enrolled in the study and completed the program. The mean total score on the primary outcome (RAS) significantly improved from -12.9 (SD = 17.2) to -8.6 (SD = 18.6) ( p  = 0.01). The within-group effect size at the post-intervention was Cohen's d = 0.24; this corresponds to the small effect of the program. Regarding secondary outcomes, there were no statistically significant effects on the BFNE or any of the BJSQ subscales (job-stressors, psychological distress, physical distress, worksite support, and satisfaction). This single-group feasibility study demonstrated that our modified brief assertiveness training for nurses seems feasible and may achieve a favorable outcome in improving their

  19. Pharmacokinetics of serelaxin in patients with hepatic impairment: a single-dose, open-label, parallel group study.

    Science.gov (United States)

    Kobalava, Zhanna; Villevalde, Svetlana; Kotovskaya, Yulia; Hinrichsen, Holger; Petersen-Sylla, Marc; Zaehringer, Andreas; Pang, Yinuo; Rajman, Iris; Canadi, Jasna; Dahlke, Marion; Lloyd, Peter; Halabi, Atef

    2015-06-01

    Serelaxin is a recombinant form of human relaxin-2 in development for treatment of acute heart failure. This study aimed to evaluate the pharmacokinetics (PK) of serelaxin in patients with hepatic impairment. Secondary objectives included evaluation of immunogenicity, safety and tolerability of serelaxin. This was an open-label, parallel group study (NCT01433458) comparing the PK of serelaxin following a single 24 h intravenous (i.v.) infusion (30 μg kg(-1)  day(-1) ) between patients with mild, moderate or severe hepatic impairment (Child-Pugh class A, B, C) and healthy matched controls. Blood sampling and standard safety assessments were conducted. Primary non-compartmental PK parameters [including area under the serum concentration-time curve AUC(0-48 h) and AUC(0-∞) and serum concentration at 24 h post-dose (C24h )] were compared between each hepatic impairment group and healthy controls. A total of 49 subjects (including 25 patients with hepatic impairment) were enrolled, of which 48 subjects completed the study. In all groups, the serum concentration of serelaxin increased over the first few hours of infusion, reached steady-state at 12-24 h and then declined following completion of infusion, with a mean terminal half-life of 7-8 h. All PK parameter estimates were comparable between each group of patients with hepatic impairment and healthy controls. No serious adverse events, discontinuations due to adverse events or deaths were reported. No serelaxin treatment-related antibodies developed during this study. The PK and safety profile of serelaxin were not affected by hepatic impairment. No dose adjustment is needed for serelaxin treatment of 48 h i.v. infusion in patients with hepatic impairment. © 2014 The British Pharmacological Society.

  20. Ants farm subterranean aphids mostly in single clone groups - an example of prudent husbandry for carbohydrates and proteins?

    Directory of Open Access Journals (Sweden)

    Ivens Aniek BF

    2012-07-01

    Full Text Available Abstract Background Mutualistic interactions are wide-spread but the mechanisms underlying their evolutionary stability and ecological dynamics remain poorly understood. Cultivation mutualisms in which hosts consume symbionts occur in phylogenetically diverse groups, but often have symbiont monocultures for each host. This is consistent with the prediction that symbionts should avoid coexistence with other strains so that host services continue to benefit relatives, but it is less clear whether hosts should always favor monocultures and what mechanisms they might have to manipulate symbiont diversity. Few mutualisms have been studied in sufficient genetic detail to address these issues, so we decided to characterize symbiont diversity in the complex mutualism between multiple root aphid species and Lasius flavus ants. After showing elsewhere that three of these aphid species have low dispersal and mostly if not exclusively asexual reproduction, we here investigate aphid diversity within and between ant nest mounds. Results The three focal species (Geoica utricularia, Forda marginata and Tetraneura ulmi had considerable clonal diversity at the population level. Yet more than half of the ant mounds contained just a single aphid species, a significantly higher percentage than expected from a random distribution. Over 60% of these single-species mounds had a single aphid clone, and clones tended to persist across subsequent years. Whenever multiple species/clones co-occurred in the same mound, they were spatially separated with more than 95% of the aphid chambers containing individuals of a single clone. Conclusions L. flavus “husbandry” is characterized by low aphid “livestock” diversity per colony, especially at the nest-chamber level, but it lacks the exclusive monocultures known from other cultivation mutualisms. The ants appear to eat most of the early instar aphids, so that adult aphids are unlikely to face limited phloem resources and

  1. [Single nucleotide polymorphisms of HIV coreceptor CCR5 gene in Chinese Yi ethnic group and its association with HIV infection].

    Science.gov (United States)

    Ma, Li-ying; Hong, Kun-xue; Lu, Xiao-zhi; Qin, Guang-ming; Chen, Jian-ping; Chen, Kang-lin; Ruan, Yu-hua; Xing, Hui; Zhu, Jia-hong; Shao, Yi-ming

    2005-11-30

    To investigate the single nucleotide polymorphism (SNP) of HIV-1 coreceptor CCR5 gene in Chinese Yi ethnic group and the association between these SNPs and HIV/AIDS. Peripheral blood samples of 102 HIV negative persons of Chinese Yi nationality, 87 males amd 15 females, aged 23 (12-37), and 68 HIV carriers, 61 males and 7 females, aged 27 (17-51). The regulatory and structural regions of the HIV coreceptor CCR5 gene were amplified from the genomic DNA by nested PCR, each of the two regions was divided into three gene fragments which were overlapped. High throughput DHPLC was used for screening of unknown mutations in each gene fragment. The PCR products showing different peak traces from wild types in DHPLC were sequenced by forward and reverse primers respectively. The sequences were analyzed with the help of Sequence Navigator software to search for SNP loci. Statistical analysis by SPSS and PPAP softwares were made to study the association between these SNPs and HIV infection. Five SNPs (A77G, G316A, T532C, C921T, and G668A) and a AGA deletion of the 686-688 nucleotides were discovered in the coding region of this gene in Chinese Yi ethnic group. C921T mutation was a nonsense mutation, and the other SNPs (A77G, G316A, T532C, and G668A) are sense mutation, with the amino acid changes of K26R, G106R, C178R, and R223Q. Only the frequency of R223Q allelic gene was high (0.08) but those of the others were low (less than 0.01). There was no significant difference in the allele frequency between the HIV negative and HIV positive groups (all P > 0.05). Five SNP loci (T58934G, G59029A, T59353C, G59402A, and C59653T) were found in the regulatory region of CCR5 gene with high allelic frequencies of 0.1912-0.2941. Between the HIV negative and HIV positive groups, there were no differences in the SNP loc (all P > 0.05). Statistical analysis of the association between the linkage of mutation loci with HIV infection suggested a significant difference in the haplotype frequency

  2. Selective 2'-hydroxyl acylation analyzed by primer extension and mutational profiling (SHAPE-MaP) for direct, versatile and accurate RNA structure analysis.

    Science.gov (United States)

    Smola, Matthew J; Rice, Greggory M; Busan, Steven; Siegfried, Nathan A; Weeks, Kevin M

    2015-11-01

    Selective 2'-hydroxyl acylation analyzed by primer extension (SHAPE) chemistries exploit small electrophilic reagents that react with 2'-hydroxyl groups to interrogate RNA structure at single-nucleotide resolution. Mutational profiling (MaP) identifies modified residues by using reverse transcriptase to misread a SHAPE-modified nucleotide and then counting the resulting mutations by massively parallel sequencing. The SHAPE-MaP approach measures the structure of large and transcriptome-wide systems as accurately as can be done for simple model RNAs. This protocol describes the experimental steps, implemented over 3 d, that are required to perform SHAPE probing and to construct multiplexed SHAPE-MaP libraries suitable for deep sequencing. Automated processing of MaP sequencing data is accomplished using two software packages. ShapeMapper converts raw sequencing files into mutational profiles, creates SHAPE reactivity plots and provides useful troubleshooting information. SuperFold uses these data to model RNA secondary structures, identify regions with well-defined structures and visualize probable and alternative helices, often in under 1 d. SHAPE-MaP can be used to make nucleotide-resolution biophysical measurements of individual RNA motifs, rare components of complex RNA ensembles and entire transcriptomes.

  3. Development of Hydroxyl Tagging Velocimetry for Low Velocity Flows

    Science.gov (United States)

    Andre, Matthieu A.; Bardet, Philippe M.; Burns, Ross A.; Danehy, Paul M.

    2016-01-01

    Hydroxyl tagging velocimetry (HTV) is a molecular tagging technique that relies on the photo-dissociation of water vapor into OH radicals and their subsequent tracking using laser induced fluorescence. Velocities are then obtained from time-of-flight calculations. At ambient temperature in air, the OH species lifetime is relatively short (<50 µs), making it suited for high speed flows. Lifetime and radicals formation increases with temperature, which allows HTV to also probe low-velocity, high-temperature flows or reacting flows such as flames. The present work aims at extending the domain of applicability of HTV, particularly towards low-speed (<10 m/s) and moderate (<500 K) temperature flows. Results are compared to particle image velocimetry (PIV) measurements recorded in identical conditions. Single shot and averaged velocity profiles are obtained in an air jet at room temperature. By modestly raising the temperature (100-200 degC) the OH production increases, resulting in an improvement of the signal-to-noise ratio (SNR). Use of nitrogen - a non-reactive gas with minimal collisional quenching - extends the OH species lifetime (to over 500 µs), which allows probing of slower flows or, alternately, increases the measurement precision at the expense of spatial resolution. Instantaneous velocity profiles are resolved in a 100degC nitrogen jet (maximum jet-center velocity of 6.5 m/s) with an uncertainty down to 0.10 m/s (1.5%) at 68% confidence level. MTV measurements are compared with particle image velocimetry and show agreement within 2%.

  4. Influence of hydroxyl content of binders on rheological properties of cerium-gadolinium oxide (CGO) screen printing inks

    DEFF Research Database (Denmark)

    Marani, Debora; Gadea, Christophe; Hjelm, Johan

    2015-01-01

    vinyl resins) were selected and characterized in solution via viscosimetry method. A high degree of hyper-entanglement was observed for ethyl cellulose polymers, whereas a mitigated effect characterized the two vinyl resins. Cerium-gadolinium oxides (CGO)-based inks, prepared using the selected binders......The influence of hydroxyl content of binders on rheological properties of screen printing inks is investigated. The actual amount of hydroxyl groups is correlated to the level of hyper-entanglement that characterizes the binders in solution. Three of the most used binders (ethyl cellulose, and two...

  5. Nanocomposites of ferroelectric polymers with surface-hydroxylated BaTiO 3 nanoparticles for energy storage applications

    KAUST Repository

    Almadhoun, Mahmoud Nassar Mahmoud

    2012-01-01

    A facile surface hydroxylation treatment using hydrogen peroxide to modify the surface of BaTiO 3 nanofillers dispersed in a ferroelectric copolymer host has been investigated. We demonstrate that the surface functionalization of the BaTiO 3 nanofillers (<100 nm) with hydroxyl groups results in as much as two orders of magnitude reduction in the leakage current of nanocomposite thin-film capacitors. This reduction is observed concurrently with the enhancement of the effective permittivity and breakdown strength of the thin-film nanocomposites. Surface modified BaTiO 3 particles display better dispersion within the polymer matrix, resulting in enhanced relative permittivity and reduced dielectric loss. The dielectric behavior of the nanocomposite films containing up to 30 vol.% BaTiO 3 agreed well with the Bruggeman model. These results demonstrate the potential of facile surface hydroxylation of nanoparticles towards the fabrication of higher energy-density nanocomposites. © 2012 The Royal Society of Chemistry.

  6. The Type and Impact of Evidence Review Group Exploratory Analyses in the NICE Single Technology Appraisal Process.

    Science.gov (United States)

    Carroll, Christopher; Kaltenthaler, Eva; Hill-McManus, Daniel; Scope, Alison; Holmes, Michael; Rice, Stephen; Rose, Micah; Tappenden, Paul; Woolacott, Nerys

    2017-06-01

    As part of the UK National Institute for Health and Care Excellence (NICE) single technology appraisal process, independent evidence review groups (ERGs) critically appraise a company's submission relating to a specific technology and indication. To explore the type of additional exploratory analyses conducted by ERGs and their impact on the recommendations made by NICE. The 100 most recently completed single technology appraisals with published guidance were selected for inclusion. A content analysis of relevant documents was undertaken to identify and extract relevant data, and narrative synthesis was used to rationalize and present these data. The types of exploratory analysis conducted in relation to companies' models were fixing errors, addressing violations, addressing matters of judgment, and the provision of a new, ERG-preferred base case. Ninety-three of the 100 ERG reports contained at least one of these analyses. The most frequently reported type of analysis in these 93 ERG reports related to the category "Matters of judgment," which was reported in 83 reports (89%). At least one of the exploratory analyses conducted and reported by an ERG is mentioned in 97% of NICE appraisal consultation documents and 94% of NICE final appraisal determinations, and had a clear influence on recommendations in 72% of appraisal consultation documents and 47% of final appraisal determinations. These results suggest that the additional analyses undertaken by ERGs in the appraisal of company submissions are highly influential in the policy-making and decision-making process. Copyright © 2017 International Society for Pharmacoeconomics and Outcomes Research (ISPOR). Published by Elsevier Inc. All rights reserved.

  7. Hydroxyl Radical-Mediated Novel Modification of Peptides: N-Terminal Cyclization through the Formation of α-Ketoamide.

    Science.gov (United States)

    Lee, Seon Hwa; Kyung, Hyunsook; Yokota, Ryo; Goto, Takaaki; Oe, Tomoyuki

    2015-01-20

    The hydroxyl radical-mediated oxidation of peptides and proteins constitutes a large group of post-translational modifications that can result in structural and functional changes. These oxidations can lead to hydroxylation, sulfoxidation, or carbonylation of certain amino acid residues and cleavage of peptide bonds. In addition, hydroxyl radicals can convert the N-terminus of peptides to an α-ketoamide via abstraction of the N-terminal α-hydrogen and hydrolysis of the ketimine intermediate. In the present study, we identified N-terminal cyclization as a novel modification mediated by a hydroxyl radical. The reaction of angiotensin (Ang) II (DRVYIHPF) and the hydroxyl radical generated by the Cu(II)/ascorbic acid (AA) system or UV/hydrogen peroxide system produced N-terminal cyclized-Ang II (Ang C) and pyruvamide-Ang II (Ang P, CH3COCONH-RVYIHPF). The structure of Ang C was confirmed by mass spectrometry and comparison to an authentic standard. The subsequent incubation of isolated Ang P in the presence of Cu(II)/AA revealed that Ang P was the direct precursor of Ang C. The proposed mechanism involves the formation of a nitrogen-centered (aminyl) radical, which cyclizes to form a five-membered ring containing the alkoxy radical. The subsequent β-scission reaction of the alkoxyl radical results in the cleavage of the terminal CH3CO group. The initial aminyl radical can be stabilized by chelation to the Cu(II) ions. The affinity of Ang C toward the Ang II type 1 receptor was significantly lower than that of Ang II or Ang P. Ang C was not further metabolized by aminopeptidase A, which converts Ang II to Ang III. Hydroxyl radical-mediated N-terminal cyclization was also observed in other Ang peptides containing N-terminal alanine, arginine, valine, and amyloid β 1-11 (DAEFRHDSGYE).

  8. Impact of Dendrimer Terminal Group Chemistry on Blockage of the Anthrax Toxin Channel: A Single Molecule Study.

    Science.gov (United States)

    Yamini, Goli; Kalu, Nnanya; Nestorovich, Ekaterina M

    2016-11-15

    Nearly all the cationic molecules tested so far have been shown to reversibly block K⁺ current through the cation-selective PA 63 channels of anthrax toxin in a wide nM-mM range of effective concentrations. A significant increase in channel-blocking activity of the cationic compounds was achieved when multiple copies of positively charged ligands were covalently linked to multivalent scaffolds, such as cyclodextrins and dendrimers. Even though multivalent binding can be strong when the individual bonds are relatively weak, for drug discovery purposes we often strive to design multivalent compounds with high individual functional group affinity toward the respective binding site on a multivalent target. Keeping this requirement in mind, here we perform a single-channel/single-molecule study to investigate kinetic parameters of anthrax toxin PA 63 channel blockage by second-generation (G2) poly(amido amine) (PAMAM) dendrimers functionalized with different surface ligands, including G2-NH₂, G2-OH, G2-succinamate, and G2-COONa. We found that the previously reported difference in IC 50 values of the G2-OH/PA 63 and G2-NH₂/PA 63 binding was determined by both on- and off-rates of the reversible dendrimer/channel binding reaction. In 1 M KCl, we observed a decrease of about three folds in k o n and a decrease of only about ten times in t r e s with G2-OH compared to G2-NH₂. At the same time for both blockers, k o n and t r e s increased dramatically with transmembrane voltage increase. PAMAM dendrimers functionalized with negatively charged succinamate, but not carboxyl surface groups, still had some residual activity in inhibiting the anthrax toxin channels. At 100 mV, the on-rate of the G2-succinamate binding was comparable with that of G2-OH but showed weaker voltage dependence when compared to G2-OH and G2-NH₂. The residence time of G2-succinamate in the channel exhibited opposite voltage dependence compared to G2-OH and G2-NH₂, increasing with the cis

  9. Serum Hydroxyl Radical Scavenging Capacity as Quantified with Iron-Free Hydroxyl Radical Source

    Science.gov (United States)

    Endo, Nobuyuki; Oowada, Shigeru; Sueishi, Yoshimi; Shimmei, Masashi; Makino, Keisuke; Fujii, Hirotada; Kotake, Yashige

    2009-01-01

    We have developed a simple ESR spin trapping based method for hydroxyl (OH) radical scavenging-capacity determination, using iron-free OH radical source. Instead of the widely used Fenton reaction, a short (typically 5 seconds) in situ UV-photolysis of a dilute hydrogen peroxide aqueous solution was employed to generate reproducible amounts of OH radicals. ESR spin trapping was applied to quantify OH radicals; the decrease in the OH radical level due to the specimen’s scavenging activity was converted into the OH radical scavenging capacity (rate). The validity of the method was confirmed in pure antioxidants, and the agreement with the previous data was satisfactory. In the second half of this work, the new method was applied to the sera of chronic renal failure (CRF) patients. We show for the first time that after hemodialysis, OH radical scavenging capacity of the CRF serum was restored to the level of healthy control. This method is simple and rapid, and the low concentration hydrogen peroxide is the only chemical added to the system, that could eliminate the complexity of iron-involved Fenton reactions or the use of the pulse-radiolysis system. PMID:19794928

  10. Rate constant for reaction of hydroxyl radicals with bicarbonate ions

    International Nuclear Information System (INIS)

    Buxton, G.V.; Elliot, A.J.

    1986-01-01

    The rate constant for reaction of hydroxyl radicals with the bicarbonate ion has been determined to be 8.5 x 10 6 dm 3 mol -1 s -1 . This value was calculated from: the measured rate of formation of the CO 3 - radical in pulsed electron irradiation of bicarbonate solutions over the pH range 7.0 to 9.4; the pK for the equilibrium HCO 3 - = CO 3 2- + H + ; and the rate constant for hydroxyl radicals reacting with the carbonate ion. (author)

  11. Steroid Hydroxylation by Basidiomycete Peroxygenases: a Combined Experimental and Computational Study

    Science.gov (United States)

    Babot, Esteban D.; del Río, José C.; Cañellas, Marina; Sancho, Ferran; Lucas, Fátima; Guallar, Víctor; Kalum, Lisbeth; Lund, Henrik; Gröbe, Glenn; Scheibner, Katrin; Ullrich, René; Hofrichter, Martin; Martínez, Angel T.

    2015-01-01

    The goal of this study is the selective oxyfunctionalization of steroids under mild and environmentally friendly conditions using fungal enzymes. With this purpose, peroxygenases from three basidiomycete species were tested for the hydroxylation of a variety of steroidal compounds, using H2O2 as the only cosubstrate. Two of them are wild-type enzymes from Agrocybe aegerita and Marasmius rotula, and the third one is a recombinant enzyme from Coprinopsis cinerea. The enzymatic reactions on free and esterified sterols, steroid hydrocarbons, and ketones were monitored by gas chromatography, and the products were identified by mass spectrometry. Hydroxylation at the side chain over the steroidal rings was preferred, with the 25-hydroxyderivatives predominating. Interestingly, antiviral and other biological activities of 25-hydroxycholesterol have been reported recently (M. Blanc et al., Immunity 38:106–118, 2013, http://dx.doi.org/10.1016/j.immuni.2012.11.004). However, hydroxylation in the ring moiety and terminal hydroxylation at the side chain also was observed in some steroids, the former favored by the absence of oxygenated groups at C-3 and by the presence of conjugated double bonds in the rings. To understand the yield and selectivity differences between the different steroids, a computational study was performed using Protein Energy Landscape Exploration (PELE) software for dynamic ligand diffusion. These simulations showed that the active-site geometry and hydrophobicity favors the entrance of the steroid side chain, while the entrance of the ring is energetically penalized. Also, a direct correlation between the conversion rate and the side chain entrance ratio could be established that explains the various reaction yields observed. PMID:25862224

  12. Hydroxyl and water molecule orientations in trypsin: Comparison to molecular dynamics structures

    Energy Technology Data Exchange (ETDEWEB)

    McDowell, R.S.; Kossiakoff, A.A. [Genentech, Inc., South San Francisco, CA (United States)

    1994-12-31

    A comparison is presented of experimentally observed hydroxyl and water hydrogens in trypsin determined from neutron density maps with the results of a 140ps molecular dynamics (MD) simulation. Experimental determination of hydrogen and deuterium atom positions in molecules as large as proteins is a unique capability of neutron diffraction. The comparison addresses the degree to which a standard force-field approach can adequately describe the local electrostatic and van der Waals forces that determine the orientations of these hydrogens. Neutron densities, derived from 2.1{Angstrom} D{sub 2}O-H{sub 2}O difference Fourier maps, provide a database of 27 well-ordered hydroxyl hydrogens. Most of the simulated hydroxyl orientations are within a standard deviation of the experimentally-observed positions, including several examples in which both the simulation and the neutron density indicate that a hydroxyl group is shifted from a {open_quote}standard{close_quote} rotamer. For the most highly ordered water molecules, the hydrogen distributions calculated from the trajectory were in good agreement with neutron density; simulated water molecules that displayed multiple hydrogen bonding networks had correspondingly broadened neutron density profiles. This comparison was facilitated by development of a method to construct a pseudo 2{Angstrom} density map based on the hydrogen atom distributions from the simulation. The degree of disorder of internal water molecules is shown to result primarily from the electrostatic environment surrounding that water molecule as opposed to the cavity size available to the molecule. A method is presented for comparing the discrete observations sampled in a dynamics trajectory with the time- averaged data obtained from X-ray or neutron diffraction studies. This method is particularly useful for statically-disordered water molecules, in which the average location assigned from a trajectory may represent a site of relatively low occupancy.

  13. Fanconi anemia complementation group A (FANCA) protein has intrinsic affinity for nucleic acids with preference for single-stranded forms.

    Science.gov (United States)

    Yuan, Fenghua; Qian, Liangyue; Zhao, Xinliang; Liu, Jesse Y; Song, Limin; D'Urso, Gennaro; Jain, Chaitanya; Zhang, Yanbin

    2012-02-10

    The Fanconi anemia complementation group A (FANCA) gene is one of 15 disease-causing genes and has been found to be mutated in ∼60% of Fanconi anemia patients. Using purified protein, we report that human FANCA has intrinsic affinity for nucleic acids. FANCA binds to both single-stranded (ssDNA) and double-stranded (dsDNA) DNAs; however, its affinity for ssDNA is significantly higher than for dsDNA in an electrophoretic mobility shift assay. FANCA also binds to RNA with an intriguingly higher affinity than its DNA counterpart. FANCA requires a certain length of nucleic acids for optimal binding. Using DNA and RNA ladders, we determined that the minimum number of nucleotides required for FANCA recognition is ∼30 for both DNA and RNA. By testing the affinity between FANCA and a variety of DNA structures, we found that a 5'-flap or 5'-tail on DNA facilitates its interaction with FANCA. A patient-derived FANCA truncation mutant (Q772X) has diminished affinity for both DNA and RNA. In contrast, the complementing C-terminal fragment of Q772X, C772-1455, retains the differentiated nucleic acid-binding activity (RNA > ssDNA > dsDNA), indicating that the nucleic acid-binding domain of FANCA is located primarily at its C terminus, where most disease-causing mutations are found.

  14. Fanconi Anemia Complementation Group A (FANCA) Protein Has Intrinsic Affinity for Nucleic Acids with Preference for Single-stranded Forms*

    Science.gov (United States)

    Yuan, Fenghua; Qian, Liangyue; Zhao, Xinliang; Liu, Jesse Y.; Song, Limin; D'Urso, Gennaro; Jain, Chaitanya; Zhang, Yanbin

    2012-01-01

    The Fanconi anemia complementation group A (FANCA) gene is one of 15 disease-causing genes and has been found to be mutated in ∼60% of Fanconi anemia patients. Using purified protein, we report that human FANCA has intrinsic affinity for nucleic acids. FANCA binds to both single-stranded (ssDNA) and double-stranded (dsDNA) DNAs; however, its affinity for ssDNA is significantly higher than for dsDNA in an electrophoretic mobility shift assay. FANCA also binds to RNA with an intriguingly higher affinity than its DNA counterpart. FANCA requires a certain length of nucleic acids for optimal binding. Using DNA and RNA ladders, we determined that the minimum number of nucleotides required for FANCA recognition is ∼30 for both DNA and RNA. By testing the affinity between FANCA and a variety of DNA structures, we found that a 5′-flap or 5′-tail on DNA facilitates its interaction with FANCA. A patient-derived FANCA truncation mutant (Q772X) has diminished affinity for both DNA and RNA. In contrast, the complementing C-terminal fragment of Q772X, C772–1455, retains the differentiated nucleic acid-binding activity (RNA > ssDNA > dsDNA), indicating that the nucleic acid-binding domain of FANCA is located primarily at its C terminus, where most disease-causing mutations are found. PMID:22194614

  15. Single case design studies in music therapy: resurrecting experimental evidence in small group and individual music therapy clinical settings.

    Science.gov (United States)

    Geist, Kamile; Hitchcock, John H

    2014-01-01

    The profession would benefit from greater and routine generation of causal evidence pertaining to the impact of music therapy interventions on client outcomes. One way to meet this goal is to revisit the use of Single Case Designs (SCDs) in clinical practice and research endeavors in music therapy. Given the appropriate setting and goals, this design can be accomplished with small sample sizes and it is often appropriate for studying music therapy interventions. In this article, we promote and discuss implementation of SCD studies in music therapy settings, review the meaning of internal study validity and by extension the notion of causality, and describe two of the most commonly used SCDs to demonstrate how they can help generate causal evidence to inform the field. In closing, we describe the need for replication and future meta-analysis of SCD studies completed in music therapy settings. SCD studies are both feasible and appropriate for use in music therapy clinical practice settings, particularly for testing effectiveness of interventions for individuals or small groups. © the American Music Therapy Association 2014. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

  16. Is modified brief assertiveness training for nurses effective? A single-group study with long-term follow-up.

    Science.gov (United States)

    Yoshinaga, Naoki; Nakamura, Yohei; Tanoue, Hiroki; MacLiam, Fionnula; Aoishi, Keiko; Shiraishi, Yuko

    2018-01-01

    To evaluate the long-term effectiveness of modified brief assertiveness training (with cognitive techniques) for nurses. Most assertiveness training takes a long time to conduct; thus, briefer training is required for universal on-the-job training in the workplace. In this single-group study, nurses received two 90-min training sessions with a 1-month interval between sessions. The degree of assertiveness was assessed by using the Rathus Assertiveness Schedule as the primary outcome, at four time points: pre- and post-training, 3-month follow-up and 6-month follow-up. A total of 33 nurses received the training, and the mean Rathus Assertiveness Schedule score improved from -14.2 (SD = 16.5) pre-training to -10.5 (SD = 18.0) post-training (p open environment for communication leads to improved job satisfaction, improved nursing care and increased patient safety. © 2017 The Authors. Journal of Nursing Management Published by John Wiley & Sons Ltd.

  17. Ponatinib for Treating Chronic Myeloid Leukaemia: An Evidence Review Group Perspective of a NICE Single Technology Appraisal.

    Science.gov (United States)

    Pandor, Abdullah; Stevenson, Matt; Stevens, John; James, Marrissa Martyn-St; Hamilton, Jean; Byrne, Jenny; Rudin, Claudius; Rawdin, Andrew; Wong, Ruth

    2018-02-26

    As part of its single technology appraisal process, the National Institute for Health and Care Excellence (NICE) invited the company that manufactures ponatinib (Inclusig ® ; Incyte Corporation) to submit evidence for the clinical and cost effectiveness for previously treated chronic myeloid leukaemia (CML) and Philadelphia-chromosome-positive acute lymphoblastic leukaemia (Ph+ ALL). This paper focusses on the three phases of CML: the chronic phase (CP), the accelerated phase (AP) and the blast crisis phase (BP). The School of Health and Related Research Technology Appraisal Group at the University of Sheffield was commissioned to act as the independent Evidence Review Group (ERG). This article presents the critical review of the company's submission by the ERG and the outcome of the NICE guidance. Clinical evidence for ponatinib was derived from a phase II, industry-sponsored, single-arm, open-label, multicentre, non-comparative study. Despite the limited evidence and potential for biases, this study demonstrated that ponatinib was likely to be an effective treatment (in terms of major cytogenetic response and major haematological response) with an acceptable safety profile for patients with CML. Given the absence of any head-to-head studies comparing ponatinib with other relevant comparators, the company undertook a matching-adjusted indirect comparison (MAIC) of ponatinib with bosutinib. The approach was only used for patients with CP-CML because comprehensive data were not available for the AP- or BP-CML groups to allow the matching technique to be used. Despite the uncertainty about the MAIC approach, ponatinib was considered likely to offer advantages over bosutinib in the third-line setting, particularly for complete cytogenetic response. The company developed two health economic models to assess the cost effectiveness of ponatinib for the treatment of patients in CP-CML or in advanced CML (AP- or BP-CML, which were modelled separately). The company did

  18. Correlation between disruptive behaviors and school grouping (single-sex vs. coeducational) in students from Callao, Peru

    OpenAIRE

    Gordillo, Enrique G.

    2013-01-01

    Debate on single-sex vs. coeducational schooling has increased over the last years. The purpose of the following study is to produce empirical evidence on this debate by comparing the frequency of disruptive behaviors in students thatattend single-sex and coeducational schools, in order to find statistical correlation.The frequency of disruptive behaviors in students coming from 5 single-sex schools was compared to that coming from 5 coeducational ones. Data came from 844 students aged 14, at...

  19. Hydroxyl radical reactivity at the air-ice interface

    Directory of Open Access Journals (Sweden)

    T. F. Kahan

    2010-01-01

    Full Text Available Hydroxyl radicals are important oxidants in the atmosphere and in natural waters. They are also expected to be important in snow and ice, but their reactivity has not been widely studied in frozen aqueous solution. We have developed a spectroscopic probe to monitor the formation and reactions of hydroxyl radicals in situ. Hydroxyl radicals are produced in aqueous solution via the photolysis of nitrite, nitrate, and hydrogen peroxide, and react rapidly with benzene to form phenol. Similar phenol formation rates were observed in aqueous solution and bulk ice. However, no reaction was observed at air-ice interfaces, or when bulk ice samples were crushed prior to photolysis to increase their surface area. We also monitored the heterogeneous reaction between benzene present at air-water and air-ice interfaces with gas-phase OH produced from HONO photolysis. Rapid phenol formation was observed on water surfaces, but no reaction was observed at the surface of ice. Under the same conditions, we observed rapid loss of the polycyclic aromatic hydrocarbon (PAH anthracene at air-water interfaces, but no loss was observed at air-ice interfaces. Our results suggest that the reactivity of hydroxyl radicals toward aromatic organics is similar in bulk ice samples and in aqueous solution, but is significantly suppressed in the quasi-liquid layer (QLL that exists at air-ice interfaces.

  20. Hydroxyl radical scavenging activity of peptide from sea cucumber ...

    African Journals Online (AJOL)

    enzyme complex, sea cucumber protein hydrolysis was carried out to obtain hydrolysates that have hydroxyl-radical-scavenging activity (HRSA). The hydrolytic process was monitored by HRSA and conditions for this process were optimized as follows: pH 6.5, temperature 35°C, 12 mg enzyme complex in a reaction solution ...

  1. Iron-functionalized Al-SBA-15 for benzene hydroxylation

    NARCIS (Netherlands)

    Li, Y.; Xia, H.; Fan, F.; Feng, Z.; Santen, van R.A.; Hensen, E.J.M.; Li, Can

    2008-01-01

    For the first time an ordered mesoporous silica (Fe–Al-SBA-15) with catalytically active isolated Fe surface species for the hydroxylation of benzene with nitrous oxide is prepared by introduction of Fe3+ in the synthesis gel of Al-SBA-15. Graphical abstract image for this article (ID: b717079c)

  2. 11 µ-Hydroxylation of cortexolone using immobilized ...

    African Journals Online (AJOL)

    Transformation of cortexolone to cortisol and prednisolone by the filamentous fungus Cunninghamella elegans protoplasts as a research tool was studied. The immobilized protoplasts of the fungus hydroxylated cortexolone at 11β -position had significantly higher activity than the free protoplasts. Sucrose as an osmotic ...

  3. Decomposition of water into highly combustible hydroxyl gas used in ...

    African Journals Online (AJOL)

    The method proposed involves the decomposition of water into highly combustible hydroxyl gas via electrolysis, which is used in internal combustion engines of electrical generators for electricity generation. The by-product obtained from combustion of this gas is water vapour and oxygen to replenish the atmosphere.

  4. Issues Related to the Frequency of Exploratory Analyses by Evidence Review Groups in the NICE Single Technology Appraisal Process.

    Science.gov (United States)

    Kaltenthaler, Eva; Carroll, Christopher; Hill-McManus, Daniel; Scope, Alison; Holmes, Michael; Rice, Stephen; Rose, Micah; Tappenden, Paul; Woolacott, Nerys

    2017-06-01

    Evidence Review Groups (ERGs) critically appraise company submissions as part of the National Institute for Health and Care Excellence (NICE) Single Technology Appraisal (STA) process. As part of their critique of the evidence submitted by companies, the ERGs undertake exploratory analyses to explore uncertainties in the company's model. The aim of this study was to explore pre-defined factors that might influence or predict the extent of ERG exploratory analyses. The aim of this study was to explore predefined factors that might influence or predict the extent of ERG exploratory analyses. We undertook content analysis of over 400 documents, including ERG reports and related documentation for the 100 most recent STAs (2009-2014) for which guidance has been published. Relevant data were extracted from the documents and narrative synthesis was used to summarise the extracted data. All data were extracted and checked by two researchers. Forty different companies submitted documents as part of the NICE STA process. The most common disease area covered by the STAs was cancer (44%), and most ERG reports (n = 93) contained at least one exploratory analysis. The incidence and frequency of ERG exploratory analyses does not appear to be related to any developments in the appraisal process, the disease area covered by the STA, or the company's base-case incremental cost-effectiveness ratio (ICER). However, there does appear to be a pattern in the mean number of analyses conducted by particular ERGs, but the reasons for this are unclear and potentially complex. No clear patterns were identified regarding the presence or frequency of exploratory analyses, apart from the mean number conducted by individual ERGs. More research is needed to understand this relationship.

  5. Hydroxyl migration disorders the surface structure of hydroxyapatite nanoparticles

    Science.gov (United States)

    Cheng, Xiajie; Wu, Hong; Zhang, Li; Ma, Xingtao; Zhang, Xingdong; Yang, Mingli

    2017-09-01

    The surface structure of nano-hydroxyapatite (HAP) was investigated using a combined simulated annealing and molecular dynamics method. The stationary structures of nano-HAP with 4-7 nm in diameter and annealed under different temperatures were analyzed in terms of pair distribution function, structural factor, mean square displacement and atomic coordination number. The particles possess different structures from bulk crystal. A clear radial change in their atomic arrangements was noted. From core to surface the structures change from ordered to disordered. A three-shell model was proposed to describe the structure evolution of nano-HAP. Atoms in the core zone keep their arrangements as in crystal, while atoms in the surface shell are in short-range order and long-range disorder, adopting a typically amorphous structure. Atoms in the middle shell have small displacements and/or deflections but basically retain their original locations as in crystal. The disordered shell is about 1 nm in thickness, in agreement with experimental observations. The disordering mainly stems from hydroxyl migration during which hydroxyls move to the surface and bond with the exposed Ca ions, and their left vacancies bring about a rearrangement of nearby atoms. The disordering is to some extent different for particles unannealed under different temperatures, resulting from fewer number of migrated hydroxyls at lower temperatures. Particles with different sizes have similar surface structures, and their surface energy decreases with increasing size. Moreover, the surface energy is reduced by hydroxyl migration because the exposed Ca ions on the surface are ionically bonded with the migrated hydroxyls. Our calculations proposed a new structure model for nano-HAP, which indicates a surface structure with activities different from those without surface reorganization. This is particularly interesting because most bioactivities of biomaterials are dominated by their surface activity.

  6. 41 CFR 301-71.102 - May we issue a single authorization for a group of employees?

    Science.gov (United States)

    2010-07-01

    ... Federal Travel Regulation System TEMPORARY DUTY (TDY) TRAVEL ALLOWANCES AGENCY RESPONSIBILITIES 71-AGENCY TRAVEL ACCOUNTABILITY REQUIREMENTS Travel Authorization § 301-71.102 May we issue a single authorization... are traveling together on a single trip. However, you must attach a list of all travelers to the...

  7. Methemoglobinemia Hemotoxicity of Some Antimalarial 8-Aminoquinoline Analogues and Their Hydroxylated Derivatives: Density Functional Theory Computation of Ionization Potentials.

    Science.gov (United States)

    Ding, Yuanqing; Liu, Haining; Tekwani, Babu L; Nanayakkara, N P Dhammika; Khan, Ikhlas A; Walker, Larry A; Doerksen, Robert J

    2016-07-18

    The administration of primaquine (PQ), an essential drug for the treatment and radical cure of malaria, can lead to methemoglobin formation and life-threatening hemolysis for glucose-6-phosphate dehydrogenase deficient patients. The ionization potential (IP, a quantitative measure of the ability to lose an electron) of the metabolites generated by antimalarial 8-aminoquinoline (8-AQ) drugs like PQ has been believed to be correlated in part to this methemoglobinemia hemotoxicity: the lower the IP of an 8-AQ derivative, the higher the concentration of methemoglobin generated. In this work, demethoxylated primaquine (AQ02) was employed as a model, by intensive computation at the B3LYP-SCRF(PCM)/6-311++G**//B3LYP/6-31G** level in water, to study the effects of hydroxylation at various positions on the ionization potential. Compared to the parent AQ02, the IPs of AQ02's metabolites hydroxylated at N1', C5, and C7 were lower by 61, 30, and 19 kJ/mol, respectively, while differences in the IP relative to PQ were small for hydroxylation at all other positions. The C6 position, at which the IP of the hydroxylated metabolite was greater than that of AQ02, by 2 kJ/mol, was found to be unique. Several literature and proposed 8-AQ analogues were studied to evaluate substituent effects on their potential to generate methemoglobin, with the finding that hydroxylations at N1' and C5 contribute the most to the potential hemotoxicity of PQ-based antimalarials, whereas hydroxylation at C7 has little effect. Phenoxylation at C5 in PQ-based 8-AQs can block the hydroxylation at C5 and reduce the potential for methemoglobin generation, while -CF3 and chlorines attached to the phenolic ring can further reduce the risk. The H-shift at N1' during the cationization of hydroxylated metabolites of 8-AQs sharply decreased their IPs, but this effect can be significantly reduced by the introduction of an electron-withdrawing group to the quinoline core. The results and this approach may be

  8. Stereoselective and regiospecific hydroxylation of ketamine and norketamine.

    Science.gov (United States)

    Desta, Zeruesenay; Moaddel, Ruin; Ogburn, Evan T; Xu, Cong; Ramamoorthy, Anuradha; Venkata, Swarajya Lakshmi Vattem; Sanghvi, Mitesh; Goldberg, Michael E; Torjman, Marc C; Wainer, Irving W

    2012-11-01

    The objective was to determine the cytochrome P450s (CYPs) responsible for the stereoselective and regiospecific hydroxylation of ketamine [(R,S)-Ket] to diastereomeric hydroxyketamines, (2S,6S;2R,6R)-HK (5a) and (2S,6R;2R,6S)-HK (5b) and norketamine [(R,S)-norKet] to hydroxynorketamines, (2S,6S;2R,6R)-HNK (4a), (2S,6R;2R,6S)-HNK (4b), (2S,5S;2R,5R)-HNK (4c), (2S,4S;2R,4R)-HNK (4d), (2S,4R;2R,4S)-HNK (4e), (2S,5R;2R,5S)-HNK (4f). The enantiomers of Ket and norKet were incubated with characterized human liver microsomes (HLMs) and expressed CYPs. Metabolites were identified and quantified using LC/MS/MS and apparent kinetic constants estimated using single-site Michaelis-Menten, Hill or substrate inhibition equation. 5a was predominantly formed from (S)-Ket by CYP2A6 and N-demethylated to 4a by CYP2B6. 5b was formed from (R)- and (S)-Ket by CYP3A4/3A5 and N-demethylated to 4b by multiple enzymes. norKet incubation produced 4a, 4c and 4f and minor amounts of 4d and 4e. CYP2A6 and CYP2B6 were the major enzymes responsible for the formation of 4a, 4d and 4f, and CYP3A4/3A5 for the formation of 4e. The 4b metabolite was not detected in the norKet incubates. 5a and 4b were detected in plasma samples from patients receiving (R,S)-Ket, indicating that 5a and 5b are significant Ket metabolites. Large variations in HNK concentrations were observed suggesting that pharmacogenetics and/or metabolic drug interactions may play a role in therapeutic response.

  9. Thyroid hormone-like and estrogenic activity of hydroxylated PCBs in cell culture

    International Nuclear Information System (INIS)

    Kitamura, Shigeyuki; Jinno, Norimasa; Suzuki, Tomoharu; Sugihara, Kazumi; Ohta, Shigeru; Kuroki, Hiroaki; Fujimoto, Nariaki

    2005-01-01

    The thyroid hormone-disrupting activity of hydroxylated PCBs was examined. 4-Hydroxy-2,2',3,4',5,5'-hexachlorobiphenyl (4-OH-2,2',3,4',5,5'-HxCB), 4-hydroxy-3,3',4',5-tetrachlorobiphenyl (4-OH-3,3',4',5-TCB) and 4,4'-dihydroxy-3,3',5,5'-tetrachlorobiphenyl (4,4'-diOH-3,3',5,5'-TCB), which have been detected as metabolites of PCBs in animals and humans, and six other 4-hydroxylated PCBs markedly inhibited the binding of triiodothyronine (1 x 10 -10 M) to thyroid hormone receptor (TR) in the concentration range of 1 x 10 -6 to 1 x 10 -4 M. However, 4-hydroxy-2',4',6'-trichlorobiphenyl (4-OH-2',4',6'-TCB), 3-hydroxy-2,2',5,5'-tetrachlorobiphenyl, 4-hydroxy-2,2',5,5'-tetrachlorobiphenyl, 4-hydroxy-2,3,3',4'-tetrachlorobiphenyl, 2,3',5,5'-tetrachlorobiphenyl and 2,3',4',5,5'-pentachlorodiphenyl did not show affinity for TR. The thyroid hormonal activity of PCBs was also examined using rat pituitary cell line GH3 cells, which grow and release growth hormone in a thyroid hormone-dependent manner. 4-OH-2,2',3,4',5,5'-HxCB, 4,4'-diOH-3,3',5,5'-TCB and 4-OH-3,3',4',5-TCB enhanced the proliferation of GH3 cells and stimulated their production of growth hormone in the concentration range of 1 x 10 -7 to 1 x 10 -4 M, while PCBs which had no affinity for thyroid hormone receptor were inactive. In contrast, only 4-OH-2',4',6'-TCB exhibited a significant estrogenic activity using estrogen-responsive reporter assay in MCF-7 cells. However, the 3,5-dichloro substitution of 4-hydroxylated PCBs markedly decreased the estrogenic activity. These results suggest that, at least for the 17 PCB congeners and hydroxylated metabolites tested, a 4-hydroxyl group in PCBs is essential for thyroid hormonal and estrogenic activities, and that 3,5-dichloro substitution favors thyroid hormonal activity, but not estrogenic activity

  10. Correlation between disruptive behaviors and school grouping (single-sex vs. coeducational in students from Callao, Peru

    Directory of Open Access Journals (Sweden)

    Enrique G. Gordillo

    2013-10-01

    Full Text Available Debate on single-sex vs. coeducational schooling has increased over the last years. The purpose of the following study is to produce empirical evidence on this debate by comparing the frequency of disruptive behaviors in students thatattend single-sex and coeducational schools, in order to find statistical correlation.The frequency of disruptive behaviors in students coming from 5 single-sex schools was compared to that coming from 5 coeducational ones. Data came from 844 students aged 14, attending public schools in Callao, Peru. Students from single-sex schools showed less frequent disruptive behavior in each of the three measured categories—disruptive behaviors, behaviors that show lack of responsibility and anti-social behavior. A weak correlation was found between each of the three categories and the main variable. The study controlled for extraneous variables.

  11. Resolving the Structure of a Well-Ordered Hydroxyl Overlayer on In2O3(111): Nanomanipulation and Theory.

    Science.gov (United States)

    Wagner, Margareta; Lackner, Peter; Seiler, Steffen; Brunsch, Achim; Bliem, Roland; Gerhold, Stefan; Wang, Zhiming; Osiecki, Jacek; Schulte, Karina; Boatner, Lynn A; Schmid, Michael; Meyer, Bernd; Diebold, Ulrike

    2017-11-28

    Changes in chemical and physical properties resulting from water adsorption play an important role in the characterization and performance of device-relevant materials. Studies of model oxides with well-characterized surfaces can provide detailed information that is vital for a general understanding of water-oxide interactions. In this work, we study single crystals of indium oxide, the prototypical transparent contact material that is heavily used in a wide range of applications and most prominently in optoelectronic technologies. Water adsorbs dissociatively already at temperatures as low as 100 K, as confirmed by scanning tunneling microscopy (STM), photoelectron spectroscopy, and density functional theory. This dissociation takes place on lattice sites of the defect-free surface. While the In 2 O 3 (111)-(1 × 1) surface offers four types of surface oxygen atoms (12 atoms per unit cell in total), water dissociation happens exclusively at one of them together with a neighboring pair of 5-fold coordinated In atoms. These O-In groups are symmetrically arranged around the 6-fold coordinated In atoms at the surface. At room temperature, the In 2 O 3 (111) surface thus saturates at three dissociated water molecules per unit cell, leading to a well-ordered hydroxylated surface with (1 × 1) symmetry, where the three water O W H groups plus the surface O S H groups are imaged together as one bright triangle in STM. Manipulations with the STM tip by means of voltage pulses preferentially remove the H atom of one surface O S H group per triangle. The change in contrast due to strong local band bending provides insights into the internal structure of these bright triangles. The experimental results are further confirmed by quantitative simulations of the STM image corrugation.

  12. Mepolizumab for Treating Severe Eosinophilic Asthma: An Evidence Review Group Perspective of a NICE Single Technology Appraisal.

    Science.gov (United States)

    Bermejo, Iñigo; Stevenson, Matt; Cooper, Katy; Harnan, Sue; Hamilton, Jean; Clowes, Mark; Carroll, Christopher; Harrison, Tim; Saha, Shironjit

    2018-02-01

    As part of its single technology appraisal (STA) process, the National Institute for Health and Care Excellence (NICE) invited the company (GlaxoSmithKline) that manufactures mepolizumab (Nucala ® ) to submit evidence on the clinical and cost effectiveness of mepolizumab for the treatment of severe eosinophilic asthma. The School of Health and Related Research Technology Appraisal Group (ScHARR-TAG) at the University of Sheffield was commissioned to act as the independent evidence review group (ERG). The ERG produced a review of the evidence for the clinical and cost effectiveness of mepolizumab as add-on to standard of care (SoC) compared with SoC and omalizumab, based upon the company's submission to NICE. The clinical-effectiveness evidence in the company's submission was based predominantly on three randomised controlled trials (DREAM, MENSA and SIRIUS) comparing add-on mepolizumab with placebo plus SoC. The relevant population was defined in terms of degree of asthma severity (four or more exacerbations in the previous year and/or dependency on maintenance oral corticosteroids [mOCS]) and degree of eosinophilia (a blood eosinophil count of ≥ 300 cells/µl in the previous year) based on post hoc subgroup analyses of the pivotal trials. Other subpopulations were considered throughout the appraisal, defined by different eosinophil measurements, number of exacerbations and dependency (or lack thereof) on mOCS. Statistically significant reductions in clinically significant exacerbations were observed in patients receiving mepolizumab compared with SoC meta-analysed across MENSA and DREAM in the modified intention-to-treat (ITT) population (rate ratio [RR] 0.51; 95% confidence interval [CI] 0.42-0.62) as well as in the relevant population (RR 0.47; 95% CI 0.36-0.62). In terms of quality of life, differences on the St. George's Respiratory Questionnaire in MENSA for add-on subcutaneous mepolizumab 100 mg vs. placebo were 7 and 7.5 units in the modified ITT and

  13. Safety and pharmacokinetics of single and multiple intravenous bolus doses of diclofenac sodium compared with oral diclofenac potassium 50 mg: A randomized, parallel-group, single-center study in healthy subjects.

    Science.gov (United States)

    Munjal, Sagar; Gautam, Anirudh; Okumu, Franklin; McDowell, James; Allenby, Kent

    2016-01-01

    In a randomized, parallel-group, single-center study in 42 healthy adults, the safety and pharmacokinetic parameters of an intravenous formulation of 18.75 and 37.5 mg diclofenac sodium (DFP-08) following single- and multiple-dose bolus administration were compared with diclofenac potassium 50 mg oral tablets. Mean AUC0-inf values for a 50-mg oral tablet and an 18.75-mg intravenous formulation were similar (1308.9 [393.0]) vs 1232.4 [147.6]). As measured by the AUC, DFP-08 18.75 mg and 37.5 mg demonstrated dose proportionality for extent of exposure. One subject in each of the placebo and DFP-08 18.75-mg groups and 2 subjects in the DFP-08 37.5-mg group reported adverse events that were considered by the investigator to be related to the study drug. All were mild in intensity and did not require treatment. Two subjects in the placebo group and 1 subject in the DFP-08 18.75-mg group reported grade 1 thrombophlebitis; no subjects reported higher than grade 1 thrombophlebitis after receiving a single intravenous dose. The 18.75- and 37.5-mg doses of intravenous diclofenac (single and multiple) were well tolerated for 7 days. Additional efficacy and safety studies are required to fully characterize the product. © 2015, The American College of Clinical Pharmacology.

  14. Ixazomib for Relapsed or Refractory Multiple Myeloma: Review from an Evidence Review Group on a NICE Single Technology Appraisal.

    Science.gov (United States)

    Armoiry, Xavier; Connock, Martin; Tsertsvadze, Alexander; Cummins, Ewen; Melendez-Torres, G J; Royle, Pam; Clarke, Aileen

    2018-03-26

    Ixazomib is an oral proteasome inhibitor used in combination with lenalidomide plus dexamethasone (IXA-LEN-DEX) and licensed for relapsed or refractory multiple myeloma. As part of a single technology appraisal (ID807) undertaken by the National Institute of Health and Care Excellence, the Evidence Review Group, Warwick Evidence was invited to independently review the evidence submitted by the manufacturer of ixazomib, Takeda UK Ltd. The main source of clinical effectiveness data about IXA-LEN-DEX came from the Tourmaline-MM1 randomized controlled trial in which 771 patients with relapsed or refractory multiple myeloma received either IXA-LEN-DEX or placebo-LEN-DEX as their second-, third-, or fourth-line treatment. Takeda estimated the cost effectiveness of IXA-LEN-DEX using a de-novo partitioned-survival model with three health states (pre-progression, post-progression, and dead). In their first submission, this model was used to estimate the cost effectiveness of IXA-LEN-DEX vs. bortezomib plus dexamethasone (BORT-DEX) in second-line treatment, and of IXA-LEN-DEX vs. LEN-DEX in third-line treatment. To estimate the relative clinical performance of IXA-LEN-DEX vs. BORT-DEX, Takeda conducted network meta-analyses for important outcomes. The network meta-analysis for overall survival was found to be flawed in several respects, but mainly because a hazard ratio input for one of the studies in the network had been inverted, resulting in a large inflation of the claimed superiority of IXA-LEN-DEX over BORT-DEX and a considerable overestimation of its cost effectiveness. In subsequent submissions, Takeda withdrew second-line treatment as an option for IXA-LEN-DEX. The manufacturer's first submission comparing IXA-LEN-DEX with LEN-DEX for third-line therapy employed Tourmaline-MM1 data from third- and fourth-line patients as proxy for a third-line population. The appraisal committee did not consider this reasonable because randomization in Tourmaline-MM1 was stratified

  15. Drug metabolism by cytochrome p450 enzymes: what distinguishes the pathways leading to substrate hydroxylation over desaturation?

    Science.gov (United States)

    Ji, Li; Faponle, Abayomi S; Quesne, Matthew G; Sainna, Mala A; Zhang, Jing; Franke, Alicja; Kumar, Devesh; van Eldik, Rudi; Liu, Weiping; de Visser, Sam P

    2015-06-15

    Cytochrome P450 enzymes are highly versatile biological catalysts in our body that react with a broad range of substrates. Key functions in the liver include the metabolism of drugs and xenobiotics. One particular metabolic pathway that is poorly understood relates to the P450 activation of aliphatic groups leading to either hydroxylation or desaturation pathways. A DFT and QM/MM study has been carried out on the factors that determine the regioselectivity of aliphatic hydroxylation over desaturation of compounds by P450 isozymes. The calculations establish multistate reactivity patterns, whereby the product distributions differ on each of the spin-state surfaces; hence spin-selective product formation was found. The electronic and thermochemical factors that determine the bifurcation pathways were analysed and a model that predicts the regioselectivity of aliphatic hydroxylation over desaturation pathways was established from valence bond and molecular orbital theories. Thus, the difference in energy of the OH versus the OC bond formed and the π-conjugation energy determines the degree of desaturation products. In addition, environmental effects of the substrate binding pocket that affect the regioselectivities were identified. These studies imply that bioengineering P450 isozymes for desaturation reactions will have to include modifications in the substrate binding pocket to restrict the hydroxylation rebound reaction. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  16. Social interaction with non-averse group-mates modifies a learned food aversion in single- and mixed-species groups of tamarins (Saguinus fuscicollis and S. labiatus).

    Science.gov (United States)

    Prescott, M J; Buchanan-Smith, H M; Smith, A C

    2005-04-01

    For social species, being a member of a cohesive group and performing activities as a coordinated unit appear to provide a mechanism for the efficient transmission of information about food. Social learning about food palatability was investigated in two captive primates, Saguinus fuscicollis and S. labiatus, which form stable and cohesive mixed-species groups in the wild. We explored whether an induced food aversion toward a preferred food is modified during and after social interaction with non-averse conspecifics or congeners. Sets of intra- and interspecific pairs were presented with two foods, one of which was considered distasteful by one of the pairs (the other was palatable), and their behavior was compared pre-interaction, during interaction, and post-interaction. For the aversely-conditioned individuals of both species, the change in social context corresponded to a change in their preference for the food that they considered unpalatable, regardless of whether they had interacted with a conspecific or congeneric pair, and the change in food preference was maintained post-interaction. In a control condition, in which averse individuals did not have the opportunity to interact with non-averse animals, S. fuscicollis sampled the preferred food, but not as quickly as when given the opportunity to interact. We conclude that the social learning demonstrated here may allow individual tamarins to track environmental change, such as fruit ripening, more efficiently than asocial learning alone, because social learners can more quickly and safely focus on appropriate behavior by sharing up-to-date foraging information. Furthermore, since the behavior of congeners, as well as conspecifics, acts to influence food choice in a more adaptive direction, social learning about food palatability may be an advantage of mixed-species group formation to tamarins of both species. Copyright 2005 Wiley-Liss, Inc

  17. A structural view on the functional importance of the sugar moiety and steroid hydroxyls of cardiotonic steroids in binding to Na,K-ATPase.

    Science.gov (United States)

    Cornelius, Flemming; Kanai, Ryuta; Toyoshima, Chikashi

    2013-03-01

    The Na,K-ATPase is specifically inhibited by cardiotonic steroids (CTSs) like digoxin and is of significant therapeutic value in the treatment of congestive heart failure and arrhythmia. Recently, new interest has arisen in developing Na,K-ATPase inhibitors as anticancer agents. In the present study, we compare the potency and rate of inhibition as well as the reactivation of enzyme activity following inhibition by various cardiac glycosides and their aglycones at different pH values using shark Na,K-ATPase stabilized in the E2MgPi or in the E2BeFx conformations. The effects of the number and nature of various sugar residues as well as changes in the positions of hydroxyl groups on the β-side of the steroid core of cardiotonic steroids were investigated by comparing various cardiac glycoside compounds like ouabain, digoxin, digitoxin, and gitoxin with their aglycones. The results confirm our previous hypothesis that CTS binds primarily to the E2-P ground state through an extracellular access channel and that binding of extracellular Na(+) ions to K(+) binding sites relieved the CTS inhibition. This reactivation depended on the presence or absence of the sugar moiety on the CTS, and a single sugar is enough to impede reactivation. Finally, increasing the number of hydroxyl groups of the steroid was sterically unfavorable and was found to decrease the inhibitory potency and to confer high pH sensitivity, depending on their position on the steroid β-face. The results are discussed with reference to the recent crystal structures of Na,K-ATPase in the unbound and ouabain-bound states.

  18. Hydroxyl-radical induced dechlorination of pentachlorophenol in water

    International Nuclear Information System (INIS)

    He Yongke; Wu Jilan; Fang Xingwang; Sonntag, C. von

    1998-01-01

    The hydroxyl-radical induced dechlorination of pentachlorophenol (PCP) in water has been investigated pulse radiolytically. Hydroxyl radicals react with PCP by both electron transfer and addition. The former process results in pentachlorophenoxyl radicals (PCP-O), the latter process followed by rapid HCl elimination gives birth to deprotonated hydroxytetrachlorophenoxyl radicals ( - O-TCP-O). These phenoxyl radicals exhibit maximum absorption around 452 nm, which hinders the proper estimation of the ratio of the two processes. However, these two processes cause different changes in conductivity. In basic solution, the electron transfer causes a conductivity increase due to the formation of OH - whereas an addition followed by HCl elimination results in a conductivity decrease. The concurrence of these two processes reduces the relative variation in conductivity, from which about 53% electron transfer is deduced

  19. On the spatial coincidence of hydroxyl and methanol masers

    Science.gov (United States)

    Hartquist, T. W.; Menten, K. M.; Lepp, S.; Dalgarno, A.

    1995-01-01

    We argue that purely gas-phase chemical models for the production of OH in hydroxyl masers around ultracompact H II regions such as W3(OH) cannot account for the CH_3OH in the methanol masers that are found to coincide with the hydroxyl masers in these sources. We suggest that the CH_3OH in the masers is injected into the gas phase by evaporation of the grain mantles, the grains being heated by the passage of weak shocks. Gas evaporation also injects H_2O into the gas. Photodissociation of H_2O, CH_3OH and OH occur at similar rates, and substantial abundances of CH_3OH and OH coexist.

  20. The Influence of Hydroxylated Carbon Nanotubes on Epoxy Resin Composites

    Directory of Open Access Journals (Sweden)

    Jiaoxia Zhang

    2012-01-01

    Full Text Available Hydroxylated multiwall carbon nanotubes (MWNTs/epoxy resin nanocomposites were prepared with ultrasonic dispersion and casting molding. The effect of hydroxylated MWNTs content on reactive activity of composites is discussed. Then the flexural and electrical properties were studied. Transmission electron microscope was employed to characterize the microstructure of nanocomposites. As a result, the reactive activity of nanocomposites obtained increases with the increasing content of MWNTs. When MWNTs content of the composites is 1 wt%, as compared to neat resin, the flexural strength increases from 143 Mpa to 156 MPa, the modulus increases from 3563 Mpa to 3691 MPa, and the volume and surface resistance of nanocomposites decrease by two orders of magnitude, respectively.

  1. Novel denture-cleaning system based on hydroxyl radical disinfection.

    Science.gov (United States)

    Kanno, Taro; Nakamura, Keisuke; Ikai, Hiroyo; Hayashi, Eisei; Shirato, Midori; Mokudai, Takayuki; Iwasawa, Atsuo; Niwano, Yoshimi; Kohno, Masahiro; Sasaki, Keiichi

    2012-01-01

    The purpose of this study was to evaluate a new denture-cleaning device using hydroxyl radicals generated from photolysis of hydrogen peroxide (H2O2). Electron spin resonance analysis demonstrated that the yield of hydroxyl radicals increased with the concentration of H2O2 and light irradiation time. Staphylococcus aureus, Pseudomonas aeruginosa, and methicillin-resistant S aureus were killed within 10 minutes with a > 5-log reduction when treated with photolysis of 500 mM H2O2; Candida albicans was killed within 30 minutes with a > 4-log reduction with photolysis of 1,000 mM H2O2. The clinical test demonstrated that the device could effectively reduce microorganisms in denture plaque by approximately 7-log order within 20 minutes.

  2. The Haber Process Made Efficient by Hydroxylated Graphene

    OpenAIRE

    Chaban, Vitaly; Prezhdo, Oleg

    2016-01-01

    The Haber-Bosch process is the main industrial method for producing ammonia from diatomic nitrogen and hydrogen. Very demanding energetically, it uses an iron catalyst, and requires high temperature and pressure. Any improvement of the Haber process will have an extreme scientific and economic impact. We report a significant increase of ammonia production using hydroxylated graphene. Exploiting the polarity difference between N2/H2 and NH3, as well as the universal proton acceptor behavior of...

  3. Regioselective hydroxylation of isoflavones by Streptomyces avermitilis MA-4680.

    Science.gov (United States)

    Roh, Changhyun; Seo, Su-Hyun; Choi, Kwon-Young; Cha, Minho; Pandey, Bishnu Prasad; Kim, June-Hyung; Park, Jun-Seong; Kim, Duck Hee; Chang, Ih Seop; Kim, Byung-Gee

    2009-07-01

    Screening of bacterial whole cells was performed for regioselective hydroxylation of daidzein and genistein. Among the strains examined, Streptomyces avermitilis MA-4680 showed high ortho-dihydroxylation activity to produce 3',4',7-trihydroxyisoflavone and 3',4',5,7-tetrahydroxyisoflavone from daidzein (4',7-dihydroxyisoflavone) and genistein (4',5,7-trihydroxyisoflavone), respectively. Using 100 mg cells (wet wt.) and 1% (v/v) Triton X100 in 1 ml of total reaction volume, where 100 microl of the substrate solution (0.5 mM in 10% (v/v) mixed solvent of DMSO:MeOH = 3:7) was added to 900 microl of potassium phosphate buffer (100 mM, pH 7.2), a 16% molar conversion yield of 3',4',7-trihydroxyisoflavone was obtained from 0.5 mM daidzein after 24 h of reaction time at 28 degrees C and 200 rpm. Ketoconazole significantly (ca. 90%) inhibited the ortho-hydroxylation activity of daidzein, suggesting that cytochrome P450 enzymes putatively play roles in regiospecific daidzein hydroxylation. The analysis of the reaction products was determined by gas chromatography/mass spectrometry (GC/MS) and (1)H NMR.

  4. Synthesis and properties evaluation of sulfobetaine surfactant with double hydroxyl

    Science.gov (United States)

    Zhou, Ming; Luo, Gang; Zhang, Ze; Li, Sisi; Wang, Chengwen

    2017-09-01

    A series of sulfobetaine surfactants {N-[(3-alkoxy-2-hydroxyl)propoxy] ethyl-N,N-dimethyl-N-(2-hydroxyl)propyl sulfonate} ammonium chloride were synthesized with raw materials containing linear saturated alcohol, N,N-dimethylethanolamine, sodium 3-chloro-2-hydroxyl propane sulfonic acid and epichlorohydrin. The molecule structures of sulfobetaine surfactants were characterized by FTIR, 1HNMR and elemental analysis. Surface tension measurements can provide us information about the surface tension at the CMC (γCMC), pC20, Γmax and Amin. The pC20 values of sulfobetaine surfactants increase with the hydrophobic chain length increasing. Amin values of the surfactants decrease with increasing hydrophobic chain length from 10 to 14. The critical micelle concentration (CMC) and surface tension (γCMC) values of the sulfobetaine surfactants decrease with increasing hydrophobic chain length from 10 to 16. The lipophilicity of surfactant was enhanced with the increase of the carbon chain, however, the ability of anti-hard water was weakened. The minimum oil/water interfacial tension of four kinds of sulfobetaine surfactants is 10-2-10-3 mN/m magnitude, which indicates that the synthesized bis-hydroxy sulfobetaine surfactants have a great ability to reduce interfacial tension in the surfactant flooding system. The surface tension (γCMC) values of synthesized surfactants were lower compared with conventional anionic surfactant sodium dodecyl sulfonate.

  5. Hydroxyl radical induced degradation of salicylates in aerated aqueous solution

    International Nuclear Information System (INIS)

    Szabó, László; Tóth, Tünde; Homlok, Renáta; Rácz, Gergely; Takács, Erzsébet; Wojnárovits, László

    2014-01-01

    Ionizing radiation induced degradation of acetylsalicylic acid, its hydrolysis product salicylic acid and a salicylic acid derivative 5-sulpho-salicylic acid, was investigated in dilute aqueous solutions by UV–vis spectrophotometry, HPLC separation and diode-array or MS/MS detection, chemical oxygen demand, total organic carbon content and by Vibrio fischeri toxicity measurements. Hydroxyl radicals were shown to degrade these molecules readily, and first degradation products were hydroxylated derivatives in all cases. Due to the by-products, among them hydrogen peroxide, the toxicity first increased and then decreased with the absorbed dose. With prolonged irradiation complete mineralization was achieved. - Highlights: • In OH induced reactions of salicylates first products are hydroxylated derivatives. • With prolonged irradiation dihydroxy derivatives also form. • In aerated solutions the one-electron oxidant OH induces 3–4 oxidations. • Toxicity first increases and then decreases with dose mainly due to H 2 O 2 formation. • The toxicity in tap water is smaller than in pure water

  6. Single Older Women Who Applied for the Giving Life More Lustre Course: Are They the Target Group that Was Aimed for?

    Science.gov (United States)

    Kremers, Ismay P.; Steverink, Nardi; Albersnagel, Frans A.; Slaets, Joris P. J.

    2007-01-01

    The present study investigated whether the women who applied for the self-management of well-being course Giving life more LUSTRE can be considered the target group that was intended. By comparing the course applicants with a random sample of community dwelling single women, it was found that, as expected, course applicants scored worse on…

  7. Single older women who applied for the giving life more lustre course : Are they the target group that was aimed for?

    NARCIS (Netherlands)

    Kremers, Ismay; Steverink, Nardi; Albersnagel, Frans A.; Slaets, Joris P. J.

    2007-01-01

    The present study investigated whether the women who applied for the self-management of well-being course Giving life more LUSTRE can be considered the target group that was intended. By comparing the course applicants with a random sample of community dwelling single women, it was found that, as

  8. Examining Students' Self-Perceived Competence and Comfort in an Experiential Play Therapy Counseling Course: A Single Group Pretest-Posttest Investigation

    Science.gov (United States)

    Flasch, Paulina; Taylor, Dalena; Clauber, Rikke Nynne; Robinson, Edward, III

    2017-01-01

    The current study utilized a single-group pretest-posttest design to evaluate students' self-perceived competence and comfort of using a variety of play therapy techniques and interventions with a range of client populations as a result of taking a one-week intensive course in Play Therapy. In an effort to conduct course evaluation and explore…

  9. Evaluating EIV, OLS, and SEM Estimators of Group Slope Differences in the Presence of Measurement Error: The Single-Indicator Case

    Science.gov (United States)

    Culpepper, Steven Andrew

    2012-01-01

    Measurement error significantly biases interaction effects and distorts researchers' inferences regarding interactive hypotheses. This article focuses on the single-indicator case and shows how to accurately estimate group slope differences by disattenuating interaction effects with errors-in-variables (EIV) regression. New analytic findings were…

  10. Baricitinib for Previously Treated Moderate or Severe Rheumatoid Arthritis: An Evidence Review Group Perspective of a NICE Single Technology Appraisal.

    Science.gov (United States)

    Ren, Shijie; Bermejo, Iñigo; Simpson, Emma; Wong, Ruth; Scott, David L; Young, Adam; Stevenson, Matt

    2018-03-03

    As part of its single technology appraisal process, the National Institute for Health and Care Excellence invited the manufacturer (Eli Lilly) of baricitinib (BARI; Olumiant ® ; a Janus kinase inhibitor that is taken orally) to submit evidence of its clinical and cost effectiveness for the treatment of moderate to severe rheumatoid arthritis (RA) after the failure of disease-modifying antirheumatic drugs (DMARDs). The School of Health and Related Research Technology Appraisal Group at the University of Sheffield was commissioned to act as the independent Evidence Review Group (ERG). The ERG produced a detailed review of the evidence for the clinical and cost effectiveness of the technology, based on the company's submission (CS) to NICE. The clinical-effectiveness evidence in the CS for BARI was based predominantly on three randomised controlled trials comparing the efficacy of BARI against adalimumab or placebo, as well as one long-term extension study. The clinical-effectiveness review identified no head-to-head evidence on the efficacy of BARI against all the comparators within the scope. Therefore, the company performed network meta-analyses (NMAs) in two different populations: one in patients who had experienced an inadequate response to conventional DMARDs (cDMARD-IR), and the other in patients who had experienced an inadequate response to tumour necrosis factor inhibitors (TNFi-IR). The company's NMAs concluded BARI had comparable efficacy as the majority of its comparators in both populations. The company submitted a de novo discrete event simulation model that analysed the incremental cost-effectiveness of BARI versus its comparators for the treatment of RA from the perspective of the National Health Service (NHS) in four different populations: (1) cDMARD-IR patients with moderate RA, defined as a 28-Joint Disease Activity Score (DAS28) > 3.2 and no more than 5.1; (2) cDMARD-IR patients with severe RA (defined as a DAS28 > 5.1); (3) TNFi-IR patients

  11. A comprehensive analysis about thermal conductivity of multi-layer graphene with N-doping, -CH3 group, and single vacancy

    Science.gov (United States)

    Si, Chao; Li, Liang; Lu, Gui; Cao, Bing-Yang; Wang, Xiao-Dong; Fan, Zhen; Feng, Zhi-Hai

    2018-04-01

    Graphene has received great attention due to its fascinating thermal properties. The inevitable defects in graphene, such as single vacancy, doping, and functional group, greatly affect the thermal conductivity. The sole effect of these defects on the thermal conductivity has been widely studied, while the mechanisms of the coupling effects are still open. We studied the combined effect of defects with N-doping, the -CH3 group, and single vacancy on the thermal conductivity of multi-layer graphene at various temperatures using equilibrium molecular dynamics with the Green-Kubo theory. The Taguchi orthogonal algorithm is used to evaluate the sensitivity of N-doping, the -CH3 group, and single vacancy. Sole factor analysis shows that the effect of single vacancy on thermal conductivity is always the strongest at 300 K, 700 K, and 1500 K. However, for the graphene with three defects, the single vacancy defect only plays a significant role in the thermal conductivity modification at 300 K and 700 K, while the -CH3 group dominates the thermal conductivity reduction at 1500 K. The phonon dispersion is calculated using a spectral energy density approach to explain such a temperature dependence. The combined effect of the three defects further decreases the thermal conductivity compared to any sole defect at both 300 K and 700 K. The weaker single vacancy effect is due to the stronger Umklapp scattering at 1500 K, at which the combined effect seriously covers almost all the energy gaps in the phonon dispersion relation, significantly reducing the phonon lifetimes. Therefore, the temperature dependence only appears on the multi-layer graphene with combined defects.

  12. Venetoclax for Treating Chronic Lymphocytic Leukaemia: An Evidence Review Group Perspective of a NICE Single Technology Appraisal.

    Science.gov (United States)

    Mistry, Hema; Nduka, Chidozie; Connock, Martin; Colquitt, Jill; Mantopoulos, Theodoros; Loveman, Emma; Walewska, Renata; Mason, James

    2018-04-01

    Venetoclax is licensed to treat relapsed or refractory (R/R) chronic lymphocytic leukaemia (CLL). As part of the Single Technology Appraisal (STA) ID944, the National Institute for Health and Care Excellence (NICE) invited AbbVie, the manufacturer, to submit evidence on the use of venetoclax, within its licensed indication. The Evidence Review Group (ERG), Warwick Evidence, was asked to provide an independent and critical review of the submitted evidence. Evidence came from three single-arm trials in CLL patients with or without 17p deletion [del(17p])/TP53 chromosomal abnormalities. The anticipated licensed indication specified that venetoclax-eligible del(17p)/TP53 patients should have not responded to, or be deemed unsuitable for, B-cell receptor inhibitor (BCRi) therapy, and that non-del(17p)/TP53 patients should have not responded to both chemoimmunotherapy and BCRi therapy. The three trials were heterogeneous in terms of both del(17p)/TP53 status and previous exposure to BCRi therapy. The M13-982 study investigated 158 R/R CLL patients with the 17p deletion, but only a small number had received previous BCRi therapy; the M12-175 study investigated 67 patients with CLL or small lymphocytic lymphoma, some with the 17p deletion, but very few previously treated with BCRi therapy; and the M14-032 study included 105 patients previously treated with BCRi therapy (either idelalisib or ibrutinib), some of whom had unknown mutation status. The ERG concluded that the study populations did not directly conform to those specified in the licensed indication or in the NICE scope. Outcomes reported included overall response rate (ORR), duration of response, progression-free survival (PFS) and overall survival (OS); adverse events were reported for the pooled population of all three studies, as well as separately for each study. The median PFS was 41.4 and 27.2 months among patients in the M12-175 and M13-982 trials, respectively, whereas the median PFS was not reached in

  13. The hydroxyl-functionalized magnetic particles for purification of glycan-binding proteins.

    Science.gov (United States)

    Sun, Xiuxuan; Yang, Ganglong; Sun, Shisheng; Quan, Rui; Dai, Weiwei; Li, Bin; Chen, Chao; Li, Zheng

    2009-12-01

    Glycan-protein interactions play important biological roles in biological processes. Although there are some methods such as glycan arrays that may elucidate recognition events between carbohydrates and protein as well as screen the important glycan-binding proteins, there is a lack of simple effectively separate method to purify them from complex samples. In proteomics studies, fractionation of samples can help to reduce their complexity and to enrich specific classes of proteins for subsequent downstream analyses. Herein, a rapid simple method for purification of glycan-binding proteins from proteomic samples was developed using hydroxyl-coated magnetic particles coupled with underivatized carbohydrate. Firstly, the epoxy-coated magnetic particles were further hydroxyl functionalized with 4-hydroxybenzhydrazide, then the carbohydrates were efficiently immobilized on hydroxyl functionalized surface of magnetic particles by formation of glycosidic bond with the hemiacetal group at the reducing end of the suitable carbohydrates via condensation. All conditions of this method were optimized. The magnetic particle-carbohydrate conjugates were used to purify the glycan-binding proteins from human serum. The fractionated glycan-binding protein population was displayed by SDS-PAGE. The result showed that the amount of 1 mg magnetic particles coupled with mannose in acetate buffer (pH 5.4) was 10 micromol. The fractionated glycan-binding protein population in human serum could be eluted from the magnetic particle-mannose conjugates by 0.1% SDS. The methodology could work together with the glycan microarrays for screening and purification of the important GBPs from complex protein samples.

  14. Brief communication genotyping of Burkholderia pseudomallei revealed high genetic variability among isolates from a single population group

    OpenAIRE

    Zueter, Abdelrahman Mohammad; Rahman, Zaidah Abdul; Yean, Chan Yean; Harun, Azian

    2015-01-01

    Burkholderia pseudomallei is a soil dwelling Gram-negative bacteria predominates in Southeast Asia zone and the tropical part of Australia. Genetic diversity has been explored among various populations and environments worldwide. To date, little data is available on MLST profiling of clinical B. pseudomallei isolates in peninsular Malaysia. In this brief report, thirteen culture positive B. pseudomallei cases collected from a single population of Terengganu state in the Western Peninsular Mal...

  15. Ants farm subterranean aphids mostly in single clone groups : An example of prudent husbandry for carbohydrates and proteins?

    NARCIS (Netherlands)

    Ivens, Aniek B. F.; Kronauer, Daniel J. C.; Pen, Ido; Weissing, Franz J.; Boomsma, Jacobus J.

    2012-01-01

    Background: Mutualistic interactions are wide-spread but the mechanisms underlying their evolutionary stability and ecological dynamics remain poorly understood. Cultivation mutualisms in which hosts consume symbionts occur in phylogenetically diverse groups, but often have symbiont monocultures for

  16. Photoinduced nuclear spin conversion of methyl groups of single molecules; Photoinduzierte Kernspinkonversion von Methylgruppen an einzelnen Molekuelen. Lochbrenn- und Einzelmolekuelspektroskopie an Terrylen und Methylderivaten

    Energy Technology Data Exchange (ETDEWEB)

    Sigl, A.

    2007-12-28

    A methyl group is an outstanding quantum system due to its special symmetry properties. The threefold rotation around one of its bond is isomorphic to the group of even permutations of the remaining protons, a property which imposes severe quantum restrictions on the system, for instance a strict correlation of rotational states with nuclear spin states. The resulting long lifetimes of the rotational tunneling states of the methyl group can be exploited for applying certain high resolution optical techniques, like hole burning or single molecule spectroscopy to optically switch the methyl group from one tunneling state to another therebye changing the nuclear spin of the protons. One goal of the thesis was to perform this switching in single methyl groups. To this end the methyl group was attached to a chromophoric system, in the present case terrylene, which is well suited for single molecule spectroscopy as well as for hole burning. Experiments were performed with the bare terrylene molecule in a hexadecane lattice which served as a reference system, with alphamethyl terrylene and betamethyl terrylene, both embedded in hexadecane, too. A single molecular probe is a highly sensitive detector for dynamic lattice instabilities. Already the bare terrylene probe showed a wealth of interesting local dynamic effects of the hexadecane lattice which could be well acounted for by the assumption of two nearly degenerate sites with rather different optical and thermal properties, all of which could be determined in a quantitative fashion. As to the methylated terrylene systems, the experiments verified that for betamethyl terrylene it is indeed possible to measure rotational tunneling events in single methyl groups. However, the spectral patterns obtained was much more complicated than expected pointing to the presence of three spectroscopically different methyl groups. In order to achieve a definite assignement, molecular mechanics simulations of the terrylene probes in the

  17. Direct Observation of a Nonheme Iron(IV)–Oxo Complex That Mediates Aromatic C–F Hydroxylation

    OpenAIRE

    Sahu, Sumit; Quesne, Matthew G.; Davies, Casey G.; Dürr, Maximilian; Ivanović-Burmazović, Ivana; Siegler, Maxime A.; Jameson, Guy N. L.; de Visser, Sam P.; Goldberg, David P.

    2014-01-01

    The synthesis of a pentadentate ligand with strategically designed fluorinated arene groups in the second coordination sphere of a nonheme iron center is reported. The oxidatively resistant fluorine substituents allow for the trapping and characterization of an FeIV(O) complex at −20 °C. Upon warming of the FeIV(O) complex, an unprecedented arene C–F hydroxylation reaction occurs. Computational studies support the finding that substrate orientation is a critical factor in the observed reactiv...

  18. The Ten-Group Robson Classification: A Single Centre Approach Identifying Strategies to Optimise Caesarean Section Rates

    Directory of Open Access Journals (Sweden)

    Keisuke Tanaka

    2017-01-01

    Full Text Available Caesarean section (CS rates have been increasing worldwide and have caused concerns. For meaningful comparisons to be made World Health Organization recommends the use of the Ten-Group Robson classification as the global standard for assessing CS rates. 2625 women who birthed over a 12-month period were analysed using this classification. Women with previous CS (group 5 comprised 10.9% of the overall 23.5% CS rate. Women with one previous CS who did not attempt VBAC contributed 5.3% of the overall 23.5% CS rate. Second largest contributor was singleton nulliparous women with cephalic presentation at term (5.1% of the total 23.5%. Induction of labour was associated with higher CS rate (groups 1 and 3 (24.5% versus 11.9% and 6.2% versus 2.6%, resp.. For postdates IOL we recommend a gatekeeper booking system to minimise these being performed <41 weeks. We suggest setting up dedicated VBAC clinic to support for women with one previous CS. Furthermore review of definition of failure to progress in labour not only may lower CS rates in groups 1 and 2a but also would reduce the size of group 5 in the future.

  19. Opticofiber photoacoustic spectrometry in single-ray two-cell grouping for analytical determination of actinoids in solutions of reprocessing

    International Nuclear Information System (INIS)

    Yin'kov, S.I.; Myasoedov, B.F.; Kikhara, T.; Fuine, S.; Maeda, M.

    1996-01-01

    Single-ray two-cell version of photoacoustic spectrometry with laser excitation (Laser Induced Photoacoustic Spectroscopy, LIPAS) for remote determination of actinoids ions in solutions is developed. The spectrometer characteristics were specified by means of uranium-containing solutions, including a great number of non-radioactive ions, the absorption bonds where of imitated the absorption of Pu(3) and Pu(4). The possibilities of the LIPAS technique were studied by analysis of ions, imitating plutonium within the range of 650-724 nm on synthetic solutions with high uranium(6) content and a great number of nonradioactive isotopes of fragmentation-type elements. 8 refs., 9 figs., 1 tab

  20. Brief communication genotyping of Burkholderia pseudomallei revealed high genetic variability among isolates from a single population group.

    Science.gov (United States)

    Zueter, Abdelrahman Mohammad; Rahman, Zaidah Abdul; Yean, Chan Yean; Harun, Azian

    2015-01-01

    Burkholderia pseudomallei is a soil dwelling Gram-negative bacteria predominates in Southeast Asia zone and the tropical part of Australia. Genetic diversity has been explored among various populations and environments worldwide. To date, little data is available on MLST profiling of clinical B. pseudomallei isolates in peninsular Malaysia. In this brief report, thirteen culture positive B. pseudomallei cases collected from a single population of Terengganu state in the Western Peninsular Malaysia and were confirmed by In-house TTS1-PCR. Isolates were subjected for multi-locus sequence typing (MLST) to explore their genotypic diversity and to investigate for possible clonal clustering of a certain sequence type. Patient's clinical information was examined to investigate for clinical correlation among the different genotypes. In spite of small sample set, MLST results indicated predictive results; considerable genotypic diversity, predominance and novelty among B. pseudomallei collected over a single geographically-located population in Malaysia. Massive genotypic heterogeneity was observed; 8 different sequence types with predominance of sequence type 54 and discovery of two novel sequence types. However, no clear pathogenomic or organ tropism clonal relationships were predicted.

  1. Gender-Role Identity and Perceived Peer Group Acceptance among Early Adolescents in Belgian Mixed and Single-Sex Schools

    Science.gov (United States)

    Brutsaert, Herman

    2006-01-01

    Drawing on survey data, this paper explores the association between early adolescents' gender-role identity and sense of peer group acceptance, and how this association may vary as a function of the gender context of the school. Two indicators of gender-role identity were included in the analysis: in one measure the items reflect features of…

  2. Determining the local origin of hydroxyl radical generation during phacoemulsification.

    Science.gov (United States)

    Aust, Steven D; Terry, Scott; Hebdon, Thomas; Gunderson, Broc; Terry, Michael; Dimalanta, Ramon

    2011-06-01

    To determine the local origin of hydroxyl radicals during phacoemulsification using an ultrasonic phacoemulsification device that includes longitudinal and torsional modalities. Chemistry and Biochemistry Department, Utah State University, Logan, Utah, USA. Experimental study. Experiments were conducted using the Infiniti Vision System and Ozil handpiece. Hydroxyl radical concentrations during longitudinal and torsional phacoemulsification were quantitated as malondialdehyde (MDA) determined spectrophotometrically using the deoxyribose assay. The difference between the total concentration found in the aspirated solution at steady-state concentrations and the pre-aspirate levels deductively determined the concentration of MDA formed along the interior of the sonicating tip. The time to reach 50% of steady state as a function of reaction vessel volume was determined. The mean maximum for torsional ultrasound at 100% amplitude was 7.70 nM ± 0.38 (SD), 91.1% of which was generated outside the tip. During longitudinal ultrasound at 100% power, MDA concentration in the aspirated solution was 29.5 ± 0.3 nM, 71.6% of which was generated outside the tip. The time (seconds) to reach 50% of maximum for longitudinal ultrasound using 5 mL, 10 mL, and 20 mL reaction vessels was 12.6 ± 1.5, 21.0 ± 1.5, and 25.3 ± 3.4, respectively. Although a significantly greater proportion of the hydroxyl radicals generated during ultrasound modality were formed outside the phaco tip (91.1% torsional; 71.6% longitudinal), torsional ultrasound generated only about one-fourth the amount of MDA as longitudinal ultrasound in total and about one-third that generated outside the tip (7.02 nM versus 21.1 nM). No author has a financial or proprietary interest in any material or method mentioned. Additional disclosures are found in the footnotes. Copyright © 2011 ASCRS and ESCRS. Published by Elsevier Inc. All rights reserved.

  3. Hydroxyl radical formation and oxidative DNA damage induced by areca quid in vivo.

    Science.gov (United States)

    Chen, Chiu-Lan; Chi, Chin-Wen; Liu, Tsung-Yun

    2002-02-01

    Chewing areca quid (AQ) has been implicated as a major risk factor for the development of oral squamous-cell carcinoma (OSCC). Recent studies have suggested that AQ-generated reactive oxygen species (ROS) is one of the contributing factors for oral carcinogenesis. However, the AQ used in Taiwan is different from that used in other countries. This study is designed to test whether ROS are generated and the consequent effects in locally prepared AQ in vivo. We measured the hydroxyl radical formation, as represented by the presence of o- and m-tyrosine in saliva from volunteers who chewed AQ containing 20 mg phenylalanine. Their saliva contained significantly higher amounts (p betel leaf. We further tested the oxidative DNA damaging effect of the reconstituted AQ, as evidenced by the elevation of 8-hydroxy-2'-deoxyguanosine (8-OH-dG) levels, in hamster buccal pouch. Following daily painting for 14 d, the 8-OH-dG level in hamster buccal pouch is significantly elevated (p < .05) in the AQ-treated group versus the controls. These findings demonstrate that ROS, such as hydroxyl radical, are formed in the human oral cavity during AQ chewing, and chewing such prepared AQ might cause oxidative DNA damage to the surrounding tissues.

  4. A first report of hydroxylated apatite as structural biomineral in Loasaceae - plants’ teeth against herbivores

    Science.gov (United States)

    Ensikat, Hans-Jürgen; Geisler, Thorsten; Weigend, Maximilian

    2016-05-01

    Biomineralization provides living organisms with various materials for the formation of resilient structures. Calcium phosphate is the main component of teeth and bones in vertebrates, whereas especially silica serves for the protection against herbivores on many plant surfaces. Functional calcium phosphate structures are well-known from the animal kingdom, but had not so far been reported from higher plants. Here, we document the occurrence of calcium phosphate biomineralization in the South-American plant group Loasaceae (rock nettle family), which have stinging trichomes similar to those of the well-known stinging nettles (Urtica). Stinging hairs and the smaller, glochidiate trichomes contained nanocrystalline hydroxylated apatite, especially in their distal portions, replacing the silica found in analogous structures of other flowering plants. This could be demonstrated by chemical, spectroscopic, and diffraction analyses. Some species of Loasaceae contained both calcium phosphate and silica in addition to calcium carbonate. The intriguing discovery of structural hydroxylated apatite in plants invites further studies, e.g., on its systematic distribution across the family, the genetic and cellular control of plant biomineralization, the properties and ultrastructure of calcium phosphate. It may prove the starting point for the development of biomimetic calcium phosphate composites based on a cellulose matrix.

  5. Group-Level EEG-Processing Pipeline for Flexible Single Trial-Based Analyses Including Linear Mixed Models.

    Science.gov (United States)

    Frömer, Romy; Maier, Martin; Abdel Rahman, Rasha

    2018-01-01

    Here we present an application of an EEG processing pipeline customizing EEGLAB and FieldTrip functions, specifically optimized to flexibly analyze EEG data based on single trial information. The key component of our approach is to create a comprehensive 3-D EEG data structure including all trials and all participants maintaining the original order of recording. This allows straightforward access to subsets of the data based on any information available in a behavioral data structure matched with the EEG data (experimental conditions, but also performance indicators, such accuracy or RTs of single trials). In the present study we exploit this structure to compute linear mixed models (LMMs, using lmer in R) including random intercepts and slopes for items. This information can easily be read out from the matched behavioral data, whereas it might not be accessible in traditional ERP approaches without substantial effort. We further provide easily adaptable scripts for performing cluster-based permutation tests (as implemented in FieldTrip), as a more robust alternative to traditional omnibus ANOVAs. Our approach is particularly advantageous for data with parametric within-subject covariates (e.g., performance) and/or multiple complex stimuli (such as words, faces or objects) that vary in features affecting cognitive processes and ERPs (such as word frequency, salience or familiarity), which are sometimes hard to control experimentally or might themselves constitute variables of interest. The present dataset was recorded from 40 participants who performed a visual search task on previously unfamiliar objects, presented either visually intact or blurred. MATLAB as well as R scripts are provided that can be adapted to different datasets.

  6. Radiolysis of the polyethylene/water system: Studies on the role of hydroxyl radical

    Energy Technology Data Exchange (ETDEWEB)

    Billamboz, Nicolas [Laboratoire de Chimie Physique et Rayonnement Alain Chambaudet, UMR CEA E4, Universite de Franche-Comte, 16 route de Gray, 25030 Besancon Cedex (France); Grivet, Manuel, E-mail: manuel.grivet@univ-fcomte.f [Laboratoire de Chimie Physique et Rayonnement Alain Chambaudet, UMR CEA E4, Universite de Franche-Comte, 16 route de Gray, 25030 Besancon Cedex (France); Foley, Sarah [Laboratoire de Chimie Physique et Rayonnement Alain Chambaudet, UMR CEA E4, Universite de Franche-Comte, 16 route de Gray, 25030 Besancon Cedex (France); Baldacchino, Gerard [CEA, IRAMIS, SIS2M, Laboratoire de Radiolyse, Bat. 546, F-91191 Gif-sur-Yvette (France); CNRS, Laboratoire Claude Frejacques, F-91191 Gif-sur-Yvette (France); Hubinois, Jean-Charles [CEA, DAM, Valduc, F-21120 Is-sur-Tille (France)

    2010-01-15

    The role of hydroxyl radical on polyethylene degradation under aqueous conditions has been studied. The reactivity of HO{sup .} towards PE is highlighted by pulse radiolysis experiments on a PE powder suspension in water using the thiocyanate competition technique. Infrared analysis of PE films irradiated in the presence of water is performed. Solutions have been either degassed with Ar, in order to remove O{sub 2} which would react with the PE, or N{sub 2}O which enhances the production of HO{sup .} radicals. Oxygenated groups and double bond groups created at the surface of PE are characterized using IR analysis, and the results for both saturated solution systems are compared.

  7. Fibrous polymer grafted magnetic chitosan beads with strong poly(cation-exchange) groups for single step purification of lysozyme.

    Science.gov (United States)

    Bayramoglu, Gulay; Tekinay, Turgay; Ozalp, V Cengiz; Arica, M Yakup

    2015-05-15

    Lysozyme is an important polypetide used in medical and food applications. We report a novel magnetic strong cation exchange beads for efficient purification of lysozyme from chicken egg white. Magnetic chitosan (MCHT) beads were synthesized via phase inversion method, and then grafted with poly(glycidyl methacrylate) (p(GMA)) via the surface-initiated atom transfer radical polymerization (SI-ATRP). Epoxy groups of the grafted polymer, were modified into strong cation-exchange groups (i.e., sulfonate groups) in the presence of sodium sulfite. The MCTH and MCTH-g-p(GMA)-SO3H beads were characterized by ATR-FTIR, SEM, and VSM. The sulphonate groups content of the modified MCTH-g-p(GMA)-4 beads was found to be 0.53mmolg(-1) of beads by the potentiometric titration method. The MCTH-g-p(GMA)-SO3H beads were first used as an ion-exchange support for adsorption of lysozyme from aqueous solution. The influence of different experimental parameters such as pH, contact time, and temperature on the adsorption process was evaluated. The maximum adsorption capacity was found to be 208.7mgg(-1) beads. Adsorption of lysozyme on the MCTH-g-p(GMA)-SO3H beads fitted to Langmuir isotherm model and followed the pseudo second-order kinetic. More than 93% of the adsorbed lysozyme was desorbed using Na2CO3 solution (pH 11.0). The purity of the lysozyme was checked by HPLC and SDS gel electrophoresis. In addition, the MCTH-g-p(GMA)-SO3H beads prepared in this work showed promising potential for separation of various anionic molecules. Copyright © 2015 Elsevier B.V. All rights reserved.

  8. Electron-withdrawing groups induced remarkable changes in sensory property based on single micro/nanostructure of perylenediimide derivatives

    International Nuclear Information System (INIS)

    Huang, Yongwei; Zhang, Weiguang; Wang, Junchao; Fu, Lina; Shi, Jiahua

    2015-01-01

    Two perylenediimide derivatives, N, N′-bis(3,7-dimethyloctyl)- 1,7-dicyanoperylene-3,4:9,10-tetracarboxyldiimide and N, N′- bis(3,7-dimethyloctyl)- 1,2,6,7-tetrachloroperylene-3,4:9,10-tetracarboxyldiimide, were prepared and their one-dimensional micro/nanorods were obtained in chloroform/methanol solution. The determination of sensing properties based on their conductometric gas sensors revealed that the increased current was one order of magnitude higher for core-tetrachlorinated perylene than that of core-cyanated one in hydrazine vapor (8 part per million). While better ambient stability in air was found for core-cyanated perylene due to its lower lowest unoccupied molecular orbital (LUMO) energy level and high-ordered arrangement in solid materials. The differential response to hydrazine vapor was less dependent on their surface area and morphologies. It should be ascribed to the difference in activation energy level and twisted skeleton, which are originated from chloride and cyano groups on the bay positions. Discussion for structure-function relationships suggest core-substituted groups have significant impact on the performance of perylene sensing device by modulating band gap and structure of skeleton. - Highlights: • PTCDIs micro/nanorods were prepared in chloroform/methanol solutions. • High sensitivities to hydrazine were found based on PTCDIs gas sensors. • It showed that core-substituted groups had impact on sensitivity and stability

  9. Bayesian framework for prediction of future number of failures from a single group of units in the field

    International Nuclear Information System (INIS)

    Ebrahimi, Nader

    2009-01-01

    This paper considers prediction of unknown number of failures in a future inspection of a group of in-service units based on number of failures observed from an earlier inspection. We develop a flexible Bayesian model and calculate Bayesian estimator for this unknown number and other quantities of interest. The paper also includes an illustration of our method in an example about heat exchanger. A main advantage of our approach is in its nonparametric nature. By nonparametric here we simply mean that no assumption is required about the failure time distribution of a unit

  10. Factors affecting hydrogen-tunneling contribution in hydroxylation reactions promoted by oxoiron(IV) porphyrin π-cation radical complexes.

    Science.gov (United States)

    Cong, Zhiqi; Kinemuchi, Haruki; Kurahashi, Takuya; Fujii, Hiroshi

    2014-10-06

    Hydrogen atom transfer with a tunneling effect (H-tunneling) has been proposed to be involved in aliphatic hydroxylation reactions catalyzed by cytochrome P450 and synthetic heme complexes as a result of the observation of large hydrogen/deuterium kinetic isotope effects (KIEs). In the present work, we investigate the factors controlling the H-tunneling contribution to the H-transfer process in hydroxylation reaction by examining the kinetics of hydroxylation reactions at the benzylic positions of xanthene and 1,2,3,4-tetrahydronaphthalene by oxoiron(IV) 5,10,15,20-tetramesitylporphyrin π-cation radical complexes ((TMP(+•))Fe(IV)O(L)) under single-turnover conditions. The Arrhenius plots for these hydroxylation reactions of H-isotopomers have upwardly concave profiles. The Arrhenius plots of D-isotopomers, clear isosbestic points, and product analysis rule out the participation of thermally dependent other reaction processes in the concave profiles. These results provide evidence for the involvement of H-tunneling in the rate-limiting H-transfer process. These profiles are simulated using an equation derived from Bell's tunneling model. The temperature dependence of the KIE values (k(H)/k(D)) determined for these reactions indicates that the KIE value increases as the reaction temperature becomes lower, the bond dissociation energy (BDE) of the C-H bond of a substrate becomes higher, and the reactivity of (TMP(+•))Fe(IV)O(L) decreases. In addition, we found correlation of the slope of the ln(k(H)/k(D)) - 1/T plot and the bond strengths of the Fe═O bond of (TMP(+•))Fe(IV)O(L) estimated from resonance Raman spectroscopy. These observations indicate that these factors modulate the extent of the H-tunneling contribution by modulating the ratio of the height and thickness of the reaction barrier.

  11. Formation of Hydroxylamine from Ammonia and Hydroxyl Radicals

    Science.gov (United States)

    Krim, Lahouari; Zins, Emilie-Laure

    2014-06-01

    In the interstellar medium, as well as in icy comets, ammonia may be a crucial species in the first step toward the formation of amino-acids and other prebiotic molecules such as hydroxylamine (NH2OH). It is worth to notice that the NH3/H2 ratio in the ISM is 3 10-5 compared the H2O/H2 one which is only 7 10-5. Using either electron-UV irradiations of water-ammonia ices or successive hydrogenation of solid nitric oxide, laboratory experiments have already shown the feasibility of reactions that may take place on the surface of ice grains in molecular clouds, and may lead to the formation of this precursor. Herein is proposed a new reaction pathway involving ammonia and hydroxyl radicals generated in a microwave discharge. Experimental studies, at 3 and 10 K, in solid phase as well as in neon matrix have shown that this reaction proceed via a hydrogen abstraction, leading to the formation of NH2 radical, that further recombine with hydroxyl radical to form hydroxylamine, under non-energetic conditions.

  12. From cation to oxide: hydroxylation and condensation of aqueous complexes

    International Nuclear Information System (INIS)

    Jolivet, J.P.

    1997-01-01

    Hydroxylation, condensation and precipitation of metal cations in aqueous solution are briefly reviewed. Hydroxylation of aqueous complexes essentially depends on the format charge (oxidation state), the size and the pH of the medium. It is the step allowing the condensation reaction. Depending on the nature of complexes (aqua-hydroxo, oxo-hydroxo), the. mechanism of condensation is different, olation or ox-olation respectively. The first one leads to poly-cations or hydroxides more or less stable against dehydration. The second one leads to poly-anions or oxides. Oligomeric species (poly-cations, poly-anions) are form from charged monomer complexes while the formation of solid phases requires non-charged precursors. Because of their high lability, charged oligomers are never the precursors of solids phases. The main routes for the formation of solid phases from solution are studied with two important and representative elements, Al and Si. For Al 3+ ions, different methods (base addition in solution, thermo-hydrolysis, hydrothermal synthesis) are discussed in relation to the crystal structure of the solid phase obtained. For silicic species condensing by ox-olation, the role of acid or base catalysis on the morphology of gels is studied. The influence of complexing ligands on the processes and on the characteristics of solids (morphology of particles, basic salts and polymetallic oxides formation) is studied. (author)

  13. Hydroxylated ceramic waste forms and the absurdity of leach tests

    Energy Technology Data Exchange (ETDEWEB)

    Roy, R; Odoj, R; Merz, E [eds.

    1981-06-01

    The repository pressure and temperature conditions during the thermal period projected in US repositories have been drastically lowered in the last year or two to new values of say 175 +- 50/sup 0/K. Using the argument that the evidence from natural models indicates the most stable mineral (= ceramic) hosts for radionuclides, one finds that under these new repository conditions such crystalline assemblages would be micas, clays, zeolites and other hydrated minerals, plus the tetravalent anhydrous oxide families. A waste form consisting of specific hydroxylated candidate phases can be made via a simple in-can technology (demonstrated by Oak Ridge) by reacting liquid wastes with precursor gels or phyllo or tektosilicates at <200/sup 0/C under modest pressure within the final disposal canister. The data on the rate of reaction of typical oxide materials to yield hydroxylated phases under these conditions show that the typical leach test (at 25 to 100/sup 0/C in deionized water) does not provide a simulation of the reactions which will occur. Hence such tests are not only totally meaningless with respect to qualifying a waste form for its role in a repository, they can be downright misleading.

  14. Hydroxylated ceramic waste forms and the absurdity of 'leach tests'

    Energy Technology Data Exchange (ETDEWEB)

    Roy, R; Odoj, R; Merz, E [eds.

    1981-06-01

    The repository pressure and temperature conditions during the thermal period projected in U.S. repositories have been drastically lowered in the last year or two to new values of say 175 +- 50 K. Using the argument that the evidence from natural models indicates the most stable mineral (= ceramic) hosts for radionuclides, one finds that under these new repository conditions such crystalline assemblages would be micas, clays, zeolites, and other hydrated minerals, plus the tetravalent anhydrous oxide families. A waste form consisting of specific hydroxylated candidate phase can be made via a simple in-can technology (demonstrated by Oak Ridge) by reacting liquid wastes with precursor gels or phyllo or tektosilicates at <200/sup 0/C under modest pressure within the final disposal canister. The data on the rate of reaction of typical oxide materials to yield hydroxylated phases under these conditions show that the typical leach test (at 25-100/sup 0/C in deionized water) does not provide a simulation of the reactions which will occur. Hence such tests are not only totally meaningless with respect to qualifying a waste form for its role in a repository, they can be downright misleading.

  15. Ixekizumab for Treating Moderate-to-Severe Plaque Psoriasis: An Evidence Review Group Perspective of a NICE Single Technology Appraisal.

    Science.gov (United States)

    Ramaekers, Bram L T; Wolff, Robert F; Pouwels, Xavier; Oosterhoff, Marije; Van Giessen, Anoukh; Worthy, Gill; Noake, Caro; Armstrong, Nigel; Kleijnen, Jos; Joore, Manuela A

    2018-02-26

    The National Institute for Health and Care Excellence invited Eli Lilly and Company Ltd, the company manufacturing ixekizumab (tradename Taltz ® ), to submit evidence for the clinical and cost effectiveness of ixekizumab. Ixekizumab was compared with tumour necrosis factor-α inhibitors (etanercept, infliximab, adalimumab), ustekinumab, secukinumab, best supportive care and, if non-biological treatment or phototherapy is suitable, also compared with systemic non-biological therapies and phototherapy with ultraviolet B radiation for adults with moderate-to-severe plaque psoriasis. Kleijnen Systematic Reviews Ltd, in collaboration with Maastricht University Medical Center, was commissioned as the independent Evidence Review Group. This article presents a summary of the company submission, the Evidence Review Group report and the development of the National Institute for Health and Care Excellence guidance for the use of this drug in England and Wales by the Appraisal Committee. The Evidence Review Group produced a critical review of the clinical and cost effectiveness of ixekizumab based on the company submission. The company submission presented three randomised controlled trials identified in a systematic review. All randomised controlled trials were phase III, multicentre placebo-controlled trials including 3866 participants with moderate-to-severe psoriasis. Two trials also included an active comparator (etanercept). All randomised controlled trials showed statistically significant increases in two primary outcomes, static Physician Global Assessment (0,1) and improvement of 75% from baseline in the Psoriasis Area and Severity Index. Ixekizumab was generally well tolerated in the randomised controlled trials, with similar discontinuation rates because of adverse events as placebo or etanercept. The most frequent adverse events of special interest were infections and injection-site reactions. The company submission also included a network meta-analysis of

  16. Effect of environmental enrichment devices on behaviors of single- and group-housed squirrel monkeys (Saimiri sciureus)

    Science.gov (United States)

    Spring, S. E.; Clifford, J. O.; Tomko, D. L.

    1997-01-01

    Squirrel monkeys display an interest in novel places, habituate to new situations, and spend most of their daily activity in the wild in large groups engaging in feeding behaviors over a broad area. Captivity limits these behaviors and consequently may disrupt normal social organizations. In captivity, squirrel monkeys may exhibit stereotypical behaviors that are believed to indicate decreased psychologic well-being. When a monkey's behavior can be made to approach that seen in the wild, and stereotypical behaviors are minimal, it is assumed that psychologic well-being is adequate. Environmental enrichment devices have been used to address the Animal Welfare Act requirement that psychologic well-being of captive nonhuman primates be considered. The purpose of the study reported here was to examine whether various environmental enrichment devices improve the psychologic well-being of captive squirrel monkeys. In the study, we used behavioral observation to quantify the effectiveness of several environmental enrichment devices for reducing stereotypical behaviors in squirrel monkeys housed alone or in groups. Analysis of our results revealed that the environmental enrichment devices did not affect the expression of normal or stereotypical behaviors, but that the type of housing did.

  17. Whole body and local cryotherapy in restless legs syndrome: A randomized, single-blind, controlled parallel group pilot study.

    Science.gov (United States)

    Happe, Svenja; Evers, Stefan; Thiedemann, Christian; Bunten, Sabine; Siegert, Rudolf

    2016-11-15

    Treatment of restless legs syndrome (RLS) is primarily based on drugs. Since many patients report improvement of symptoms due to cooling their legs, we examined the efficacy of cryotherapy in RLS. 35 patients (28 women, 60.9±12.5years) with idiopathic RLS and symptoms starting not later than 6pm were randomized into three groups: cold air chamber at -60°C (n=12); cold air chamber at -10°C (n=12); local cryotherapy at -17°C (n=11). After a two week baseline, the different therapies were applied three minutes daily at 6pm over two weeks, followed by a four week observation period. The patients completed several questionnaires regarding RLS symptoms, sleep, and quality of life on a weekly basis (IRLS, ESS), VAS and sleep/morning protocol were completed daily, MOSS/RLS-QLI were completed once in each period. Additionally, the PLM index was measured by a mobile device at the end of baseline, intervention, and follow-up. The IRLS score was chosen as primary efficacy parameter. At the end of follow-up, significant improvement of RLS symptoms and quality of life could be observed only in the -60°C group as compared to baseline (IRLS: p=0.009; RLS-QLI: p=0.006; ESS: p=0.020). Local cryotherapy led to improvement in quality of life (VAS4: p=0.028; RLS-QLI: p=0.014) and sleep quality (MOSS: p=0.020; MOSS2: p=0.022) but not in IRLS and ESS. In the -10°C group, the only significant effect was shortening of number of wake phases per night. Serious side-effects were not reported. Whole body cryotherapy at -60°C and, to a less extent, local cryotherapy seem to be a treatment option for RLS in addition to conventional pharmacological treatment. However, the exact mode of cryotherapy needs to be established. Copyright © 2016. Published by Elsevier B.V.

  18. The effect of non-weight bearing group-exercising on females with non-specific chronic low back pain: a randomized single blind controlled pilot study.

    Science.gov (United States)

    Masharawi, Youssef; Nadaf, Nedal

    2013-01-01

    The aim of this study was to investigate the effect of active non-weight-bearing (NWB) group exercising on women with non specific chronic low back pain (NSCLBP). Forty females with NSCLBP were assigned in a randomized control longitudinal single blinded pilot study. 20 of them were assigned to a NWB bi-weekly group exercise class and 20 females were included in the control group. The exercises involved the entire lumbo-pelvic spine aimed at improving lumbar mobility/flexibility and stability. Pain intensity (VAS), back specific disability (Rolland Morris questionnaire-RMQ), and lumbar flexion and extension ranges of motion measurements were taken prior to intervention (t(0)), immediately following 4 weeks of intervention (t(1)) and 8 weeks later (t(fu)). Reliability trials were conducted on 10 females. Non-parametric tests were used for statistical significance (p exercising improves functional, painful status, lumbar flexion and extension ranges of motion in women suffering from NSCLBP.

  19. The stability of the hydroxylated (0001) surface of alpha-Al2O3

    DEFF Research Database (Denmark)

    Lodziana, Zbigniew; Nørskov, Jens Kehlet; Stoltze, Per

    2003-01-01

    Self-consistent density functional calculations of the hydroxylated (0001) corundum surfaces are presented. It is demonstrated that the hydroxylated surfaces are the most stable under most, but not all, conditions. Hydroxylation significantly lowers the surface free energy of alpha-alumina. The s......Self-consistent density functional calculations of the hydroxylated (0001) corundum surfaces are presented. It is demonstrated that the hydroxylated surfaces are the most stable under most, but not all, conditions. Hydroxylation significantly lowers the surface free energy of alpha......-alumina. The stability of the hydrated surface resolves the discrepancies between the morphology of the alpha-alumina (0001) surface observed under ultra-high vacuum, and at ambient conditions. A method for the calculation of the equilibrium surface stoichiometry is proposed. The proposed approach provides a valuable...

  20. Early-onset group B streptococcal disease following culture-based screening in Japan: a single center study.

    Science.gov (United States)

    Miyata, Akane; Takahashi, Hironori; Kubo, Takahiko; Watanabe, Noriyoshi; Tsukamoto, Keiko; Ito, Yushi; Sago, Haruhiko

    2012-08-01

    We investigated trends in early-onset group B streptococcal disease (EOD) after the introduction of culture-based screening in Japan. A retrospective cohort study examined EOD trends in 9506 pregnancies and 10 715 neonates at our center from 2002 to 2009. EOD occurred in four neonates (4/7332: 0.55/1000 live births). The EOD incidence among infants born to women positive for GBS by screening was 0.90 cases per 1000 live births (1/1107). In contrast, the EOD incidence among infants negative by GBS screening was 0.48 cases per 1000 live births (3/6225). Thus, of the four affected neonates, three had mothers who tested negative on antepartum GBS screening. Two neonates had symptoms of infection during labor and intrapartum antibiotic agents were administered. The other two neonates received no antibiotics because deliveries were uneventful and they were negative on GBS screening. The incidence of EOD is 0.90 cases per 1000 live births among GBS-positive women and 0.48 cases per 1000 live births among GBS-negative women. The results of our study implied that EOD can develop regardless of GBS screening and intrapartum clinical course, although the method of sample collection, indications for antibiotic prophylaxis, and the antibiotics regimen should be considered. © 2012 The Authors. Journal of Obstetrics and Gynaecology Research © 2012 Japan Society of Obstetrics and Gynecology.

  1. Hybrid Pareto artificial bee colony algorithm for multi-objective single machine group scheduling problem with sequence-dependent setup times and learning effects.

    Science.gov (United States)

    Yue, Lei; Guan, Zailin; Saif, Ullah; Zhang, Fei; Wang, Hao

    2016-01-01

    Group scheduling is significant for efficient and cost effective production system. However, there exist setup times between the groups, which require to decrease it by sequencing groups in an efficient way. Current research is focused on a sequence dependent group scheduling problem with an aim to minimize the makespan in addition to minimize the total weighted tardiness simultaneously. In most of the production scheduling problems, the processing time of jobs is assumed as fixed. However, the actual processing time of jobs may be reduced due to "learning effect". The integration of sequence dependent group scheduling problem with learning effects has been rarely considered in literature. Therefore, current research considers a single machine group scheduling problem with sequence dependent setup times and learning effects simultaneously. A novel hybrid Pareto artificial bee colony algorithm (HPABC) with some steps of genetic algorithm is proposed for current problem to get Pareto solutions. Furthermore, five different sizes of test problems (small, small medium, medium, large medium, large) are tested using proposed HPABC. Taguchi method is used to tune the effective parameters of the proposed HPABC for each problem category. The performance of HPABC is compared with three famous multi objective optimization algorithms, improved strength Pareto evolutionary algorithm (SPEA2), non-dominated sorting genetic algorithm II (NSGAII) and particle swarm optimization algorithm (PSO). Results indicate that HPABC outperforms SPEA2, NSGAII and PSO and gives better Pareto optimal solutions in terms of diversity and quality for almost all the instances of the different sizes of problems.

  2. A novel asymmetric chair-like hydroxyl-bridged tetra-copper compound: Synthesis, supramolecular structure and magnetic property

    Science.gov (United States)

    Wang, Xiao-Feng; Du, Ke-Jie; Wang, Hong-Qing; Zhang, Xue-Li; Nie, Chang-Ming

    2017-06-01

    A new polynuclear Cu(II) compound, [Cu4(bpy)4(OH)4(H2O)(BTC)]NO3·8H2O (1), was prepared by self-assembly from the solution of copper(II) nitrate and two kinds of ligands, 2,2‧-bipyridine (bpy) and benzene-tricarboxylic acid (H3BTC). Single crystal structure analysis reveals that 1 features a rare asymmetric chair-like hydroxyl-bridged tetra-copper cluster: [Cu4(OH)4] core along with one H2O and one BTC3- occupied each terminal coordinated site. In addition, the magnetic property has been investigated.

  3. The Creation and Physiological Relevance of Divergent Hydroxylation Patterns in the Flavonoid Pathway

    Directory of Open Access Journals (Sweden)

    Heidi Halbwirth

    2010-02-01

    Full Text Available Flavonoids and biochemically-related chalcones are important secondary metabolites, which are ubiquitously present in plants and therefore also in human food. They fulfill a broad range of physiological functions in planta and there are numerous reports about their physiological relevance for humans. Flavonoids have in common a basic C6-C3-C6 skeleton structure consisting of two aromatic rings (A and B and a heterocyclic ring (C containing one oxygen atom, whereas chalcones, as the intermediates in the formation of flavonoids, have not yet established the heterocyclic C-ring. Flavonoids are grouped into eight different classes, according to the oxidative status of the C-ring. The large number of divergent chalcones and flavonoid structures is from the extensive modification of the basic molecules. The hydroxylation pattern influences physiological properties such as light absorption and antioxidative activity, which is the base for many beneficial health effects of flavonoids. In some cases antiinfective properties are also effected.

  4. A d-statistic for single-case designs that is equivalent to the usual between-groups d-statistic.

    Science.gov (United States)

    Shadish, William R; Hedges, Larry V; Pustejovsky, James E; Boyajian, Jonathan G; Sullivan, Kristynn J; Andrade, Alma; Barrientos, Jeannette L

    2014-01-01

    We describe a standardised mean difference statistic (d) for single-case designs that is equivalent to the usual d in between-groups experiments. We show how it can be used to summarise treatment effects over cases within a study, to do power analyses in planning new studies and grant proposals, and to meta-analyse effects across studies of the same question. We discuss limitations of this d-statistic, and possible remedies to them. Even so, this d-statistic is better founded statistically than other effect size measures for single-case design, and unlike many general linear model approaches such as multilevel modelling or generalised additive models, it produces a standardised effect size that can be integrated over studies with different outcome measures. SPSS macros for both effect size computation and power analysis are available.

  5. Self-hydroxylation of the splicing factor lysyl hydroxylase, JMJD6

    DEFF Research Database (Denmark)

    Mantri, M.; Webby, C.J.; Loik, N.D.

    2012-01-01

    The lysyl 5S-hydroxylase, JMJD6 acts on proteins involved in RNA splicing. We find that in the absence of substrate JMJD6 catalyses turnover of 2OG to succinate. H-NMR analyses demonstrate that consumption of 2OG is coupled to succinate formation. MS analyses reveal that JMJD6 undergoes self......-hydroxylation in the presence of Fe(ii) and 2OG resulting in production of 5S-hydroxylysine residues. JMJD6 in human cells is also found to be hydroxylated. Self-hydroxylation of JMJD6 may play a regulatory role in modulating the hydroxylation status of proteins involved in RNA splicing. This journal is...

  6. Fabrication and characterization of a novel hydrophobic CaCO{sub 3} grafted by hydroxylated poly(vinyl chloride) chains

    Energy Technology Data Exchange (ETDEWEB)

    Bao, Lixia [State Key Laboratory of Polymer Materials Engineering, Sichuan University (China); School of Chemical Science and Technology, Yunnan University (China); Yang, Simei; Luo, Xin [School of Chemical Science and Technology, Yunnan University (China); Lei, Jingxin [State Key Laboratory of Polymer Materials Engineering, Sichuan University (China); Cao, Qiue [School of Chemical Science and Technology, Yunnan University (China); Wang, Jiliang, E-mail: jlwang@ynu.edu.cn [School of Chemical Science and Technology, Yunnan University (China)

    2015-12-01

    Highlights: • Hydroxylated poly(vinyl chloride) (PVC-OH) with different molecular weight and hydroxyl value was successfully prepared by the suspension copolymerization. • PVC-OH was grafted onto the surface of CaCO{sub 3} particles by the urethane formation reaction. • The modified CaCO{sub 3} particles show excellent hydrophobicity. - Abstract: The hydroxylated PVC (PVC-OH) was successfully synthesized by a suspension polymerization of vinyl chloride (VC), butyl acrylate (BA) and hydroxyethyl acrylate (HEA). Novel hydrophobic CaCO{sub 3} was then prepared by a urethane formation reaction between methylene diphenyl diisocyanate (MDI) and the −OH groups both in the PVC-OH chains and on the surface of pristine CaCO{sub 3} particles. The effect of the PVC-OH content on the grafting ratio of treated CaCO{sub 3} particles was extensively investigated. Combining the result of Fourier transform infrared (FTIR) with that of water contact angle, it can be concluded that the hydrophobicity of CaCO{sub 3} had been efficiently improved by the PVC-OH segments grafted on the surface of CaCO{sub 3} particles. X-ray diffraction (XRD), thermal gravity analysis (TGA), scanning electron microscope (SEM) and transmission electron microscope (TEM) were also used to study crystalline behaviors, thermal stability and surface morphology of the modified CaCO{sub 3} particles, respectively. The change of specific surface area implying surface modification was investigated as well.

  7. Synthesis of hydroxylated and methoxylated polybrominated diphenyl ethers

    Institute of Scientific and Technical Information of China (English)

    ZHENG Ke-wen; GAO Li-ping; CAO Jie; YU Hai-wen; ZHANG Zhang

    2009-01-01

    Hydroxylated/methoxylated polybrominated diphenyl ethers (OH/MeO-PBDEs) are not only detected as natural products, but also regarded as metabolites formed from polybrominated diphenyl ethers (PBDEs), which are widely used as flame-retardants in various materials. The aim of the present study was to synthesize authentic OH-PBDEs and MeO-PBDEs, as reference standards for environmental exploration. Twenty OH-PBDEs and their corresponding MeO-PBDEs containing three to six bromine atoms were synthesized via a trial of reactions including coupling, oxidation, bromination, methylation, etc. The products were characterized by GC-MS and 1H-NMR spectroscopy in the work. As results show, all compounds synthesized were up to 99% on purity and be reqarded as authentic standards for detecting the chemical pollutants in the emvironment.

  8. Chemical models of chains electron transfer in hydroxylating ferment systems

    International Nuclear Information System (INIS)

    Akhrem, A.A.; Kiselev, P.A.; Metelitsa, D.I.

    1977-01-01

    The rate constants are measured of consumption of nicotineamidedinucleotide (NAD-N) during its oxidation by molecular oxygen with the participation of Ti 4+ , Sn 4+ , Cu 2+ , Fe 3+ , VO 2+ , and Ce 4+ ions in mixtures of acetonitrile with water and of dioxane with water taken in a volume ratio of 1:1 (46 deg C). The kinetics of oxidation of NAD-N with the participation of Ti 4+ at 37 deg C in a water-acetonitrile medium is studied in detail. The hydroxylating capacity of the system NAD-N - Ti 4+ - O 2 with respect to naphthalene is proved. The reaction mechanism and its relationship with the microsomal chains of electron transport are discussed

  9. Spectroscopy and reaction dynamics of collision complexes containing hydroxyl radicals

    Energy Technology Data Exchange (ETDEWEB)

    Lester, M.I. [Univ. of Pennsylvania, Philadelphia (United States)

    1993-12-01

    The DOE supported work in this laboratory has focused on the spectroscopic characterization of the interaction potential between an argon atom and a hydroxyl radical in the ground X{sup 2}II and excited A {sup 2}{summation}{sup +} electronic states. The OH-Ar system has proven to be a test case for examining the interaction potential in an open-shell system since it is amenable to experimental investigation and theoretically tractable from first principles. Experimental identification of the bound states supported by the Ar + OH (X {sup 2}II) and Ar + OH(A {sup 2}{summation}{sup +}) potentials makes it feasible to derive realistic potential energy surfaces for these systems. The experimentally derived intermolecular potentials provide a rigorous test of ab initio theory and a basis for understanding the dramatically different collision dynamics taking place on the ground and excited electronic state surfaces.

  10. The importance of a single methyl group in determining the reaction chemistry of pentamethylcyclopentadienyl cyclooctatetraenyl uranium metallocenes

    Energy Technology Data Exchange (ETDEWEB)

    Takase, Michael K.; Ziller, Joseph W.; Evans, William J. [Department of Chemistry, University of California, Irvine, CA (United States)

    2011-04-18

    The steric factors that allow trivalent [(C{sub 5}Me{sub 5}){sub 3}U] (1) to function as a three-electron reductant with C{sub 8}H{sub 8} to form tetravalent [{(C_5Me_5)(C_8H_8)U}{sub 2}(μ-C{sub 8}H{sub 8})] (2) have been explored by examining the synthesis and reactivity of the intermediate, ''[(C{sub 5}Me{sub 5}){sub 2}(C{sub 8}H{sub 8})U]'' (3), and the slightly less crowded analogues, [(C{sub 5}Me{sub 5})(C{sub 5}Me{sub 4}H)(C{sub 8}H{sub 8})U] and [(C{sub 5}Me{sub 4}H){sub 2}(C{sub 8}H{sub 8})U], that have, successively one less methyl group. The reaction of [{(C_5Me_5)(C_8H_8)U(μ-OTf)}{sub 2}] (4; OTf=OSO{sub 2}CF{sub 3}) with two equivalents of KC{sub 5}Me{sub 5} in THF gave ring-opening to ''[(C{sub 5}Me{sub 5})(C{sub 8}H{sub 8})U{O(CH_2)_4(C_5Me_5)}]'' consistent with in situ formation of 3. Reaction of 4 with two and four equivalents of KC{sub 5}Me{sub 4}H generates two equivalents of [(C{sub 5}Me{sub 5})(C{sub 5}Me{sub 4}H)(C{sub 8}H{sub 8})U] (5) and [(C{sub 5}Me{sub 4}H){sub 2}(C{sub 8}H{sub 8})U] (6), respectively, which in contrast to 3 were isolable. Tetravalent 5 reduces phenazine and PhEEPh (E=S, Se, and Te) to form the tetravalent uranium reduction products, [{(C_5Me_5)(C_8H_8)U}{sub 2}(μ-C{sub 12}H{sub 8}N{sub 2})] (7), [{(C_5Me_5)(C_8H_8)U}{sub 2}(μ-SPh){sub 2}] (8), [{(C_5Me_5)(C_8H_8)U}{sub 2}(μ-SePh){sub 2}] (9), and [{(C_5Me_5)(C_8H_8)U}{sub 2}(μ-TePh){sub 2}] (10), consistent with sterically induced reduction. In contrast, the less sterically crowded 6 does not react with these substrates. (Copyright copyright 2011 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  11. Studies on 16α-Hydroxylation of Steroid Molecules and Regioselective Binding Mode in Homology-Modeled Cytochrome P450-2C11

    Directory of Open Access Journals (Sweden)

    Hamed I. Ali

    2011-01-01

    Full Text Available We investigated the 16α-hydroxylation of steroid molecules and regioselective binding mode in homology-modeled cytochrome P450-2C11 to correlate the biological study with the computational molecular modeling. It revealed that there was a positive relationship between the observed inhibitory potencies and the binding free energies. Docking of steroid molecules into this homology-modeled CYP2C11 indicated that 16α-hydroxylation is favored with steroidal molecules possessing the following components, (1 a bent A-B ring configuration (5β-reduced, (2 C-3 α-hydroxyl group, (3 C-17β-acetyl group, and (4 methyl group at both the C-18 and C-19. These respective steroid components requirements were defined as the inhibitory contribution factor. Overall studies of the male rat CYP2C11 metabolism revealed that the above-mentioned steroid components requirements were essential to induce an effective inhibition of [3H]progesterone 16α-hydroxylation. As far as docking of homology-modeled CYP2C11 against investigated steroids is concerned, they are docked at the active site superimposed with flurbiprofen. It was also found that the distance between heme iron and C16α-H was between 4 to 6 Å and that the related angle was in the range of 180±45∘.

  12. Combination of electromembrane extraction and liquid-phase microextraction in a single step: Simultaneous group separation of acidic and basic drugs

    DEFF Research Database (Denmark)

    Huang, Chuixiu; Seip, Knut Fredrik; Gjelstad, Astrid

    2015-01-01

    at high concentration. This approach was further investigated from human plasma. Extraction recoveries were strongly dependent on dilution of plasma with buffer and on extraction time. Finally, this simultaneous EME/LPME approach was evaluated in combination with liquid chromatography (LC......Electromembrane extraction (EME) and liquid-phase microextraction (LPME) were combined in a single step for the first time to realize simultaneous and clear group separation of basic and acidic drugs. Using 2-nitrophenyl octyl ether as the supported liquid membrane (SLM) for EME and dihexyl ether...

  13. A Comparison of Cats (Felis silvestris catus Housed in Groups and Single Cages at a Shelter: A Retrospective Matched Cohort Study

    Directory of Open Access Journals (Sweden)

    Malini Suchak

    2018-02-01

    Full Text Available The merits of various housing options for domestic cats in shelters have been debated. However, comparisons are difficult to interpret because cats are typically not able to be randomly assigned to different housing conditions. In the current study, we attempted to address some of these issues by creating a retrospective matched cohort of cats in two housing types. Cats in group housing (GH were matched with cats in single housing (SH that were the same age, sex, breed, coat color, and size. Altogether we were able to find a match for 110 GH cats. We compared these two groups on several measures related to their experience at the shelter such as moves and the development of behavioral problems. We also compared these groups on outcomes including length of stay, live release, and returns after adoption. We found that while the frequency of moves was similar in both groups, SH cats were more likely to be moved to offsite facilities than GH cats. SH cats also spent a smaller proportion of time on the adoption floor. Length of stay and, live release and returns after adoption did not significantly differ across groups, however GH cats were two times as likely to be returned after adoption. Future research should look at the behavioral impacts of shelter decision-making regarding moving and management of cats in different housing systems.

  14. Experiments and simulations of NOx formation in the combustion of hydroxylated fuels

    KAUST Repository

    Bohon, Myles

    2015-06-01

    This work investigates the influence of molecular structure in hydroxylated fuels (i.e. fuels with one or more hydroxyl groups), such as alcohols and polyols, on NOx formation. The fuels studied are three lower alcohols (methanol, ethanol, and n-propanol), two diols (1,2-ethanediol and 1,2-propanediol), and one triol (1,2,3-propanetriol); all of which are liquids at room temperature and span a wide range of thermophysical properties. Experimental stack emissions measurements of NO/NO2, CO, and CO2 and flame temperature profiles utilizing a rake of thermocouples were obtained in globally lean, swirling, liquid atomized spray flames inside a refractory-lined combustion chamber as a function of the atomizing air flow rate and swirl number. These experiments show significantly lower NOx formation with increasing fuel oxygen content despite similarities in the flame temperature profiles. By controlling the temperature profiles, the contribution to NOx formation through the thermal mechanism were matched, and variations in the contribution through non-thermal NOx formation pathways are observed. Simulations in a perfectly stirred reactor, at conditions representative of those measured within the combustion region, were conducted as a function of temperature and equivalence ratio. The simulations employed a detailed high temperature chemical kinetic model for NOx formation from hydroxylated fuels developed based on recent alcohol combustion models and extended to include polyol combustion chemistry. These simulations provide a qualitative comparison to the range of temperatures and equivalence ratios observed in complex swirling flows and provide insight into the influence of variations in the fuel decomposition pathways on NOx formation. It is observed that increasing the fuel bound oxygen concentration ultimately reduces the formation of NOx by increasing the proportion of fuel oxidized through formaldehyde, as opposed to acetylene or acetaldehyde. The subsequent

  15. Genomic diversity and affinities in population groups of North West India: an analysis of Alu insertion and a single nucleotide polymorphism.

    Science.gov (United States)

    Saini, J S; Kumar, A; Matharoo, K; Sokhi, J; Badaruddoza; Bhanwer, A J S

    2012-12-15

    The North West region of India is extremely important to understand the peopling of India, as it acted as a corridor to the foreign invaders from Eurasia and Central Asia. A series of these invasions along with multiple migrations led to intermixture of variable populations, strongly contributing to genetic variations. The present investigation was designed to explore the genetic diversities and affinities among the five major ethnic groups from North West India; Brahmin, Jat Sikh, Bania, Rajput and Gujjar. A total of 327 individuals of the abovementioned ethnic groups were analyzed for 4 Alu insertion marker loci (ACE, PV92, APO and D1) and a Single Nucleotide Polymorphism (SNP) rs2234693 in the intronic region of the ESR1 gene. Statistical analysis was performed to interpret the genetic structure and diversity of the population groups. Genotypes for ACE, APO, ESR1 and PV92 loci were found to be in Hardy-Weinberg equilibrium in all the ethnic groups, while significant departures were observed at the D1 locus in every investigated population after Bonferroni's correction. The average heterozygosity for all the loci in these ethnic groups was fairly substantial ranging from 0.3927 ± 0.1877 to 0.4333 ± 0.1416. Inbreeding coefficient indicated an overall 10% decrease in heterozygosity in these North West Indian populations. The gene differentiation among the populations was observed to be of the order of 0.013. Genetic distance estimates revealed that Gujjars were close to Banias and Jat Sikhs were close to Rajputs. Overall the study favored the recent division of the populations of North West India into largely endogamous groups. It was observed that the populations of North West India represent a more or less homogenous genetic entity, owing to their common ancestral history as well as geographical proximity. Copyright © 2012 Elsevier B.V. All rights reserved.

  16. A Randomized Single Blind Parallel Group Study Comparing Monoherbal Formulation Containing Holarrhena antidysenterica Extract with Mesalamine in Chronic Ulcerative Colitis Patients

    Directory of Open Access Journals (Sweden)

    Sarika Johari

    2016-01-01

    Full Text Available Background: Incidences of side effects and relapses are very common in chronic ulcerative colitis patients after termination of the treatment. Aims and Objectives: This study aims to compare the treatment with monoherbal formulation of Holarrhena antidysenterica with Mesalamine in chronic ulcerative colitis patients with special emphasis to side effects and relapse. Settings and Design: Patients were enrolled from an Ayurveda Hospital and a private Hospital, Gujarat. The study was randomized, parallel group and single blind design. Materials and Methods: The protocol was approved by Institutional Human Research Ethics Committee of Anand Pharmacy College on 23rd Jan 2013. Three groups (n = 10 were treated with drug Mesalamine (Group I, monoherbal tablet (Group II and combination of both (Group III respectively. Baseline characteristics, factors affecting quality of life, chronicity of disease, signs and symptoms, body weight and laboratory investigations were recorded. Side effects and complications developed, if any were recorded during and after the study. Statistical Analysis Used: Results were expressed as mean ± SEM. Data was statistically evaluated using t-test, Wilcoxon test, Mann Whitney U test, Kruskal Wallis test and ANOVA, wherever applicable, using GraphPad Prism 6. Results: All the groups responded positively to the treatments. All the patients were positive for occult blood in stool which reversed significantly after treatment along with rise in hemoglobin. Patients treated with herbal tablets alone showed maximal reduction in abdominal pain, diarrhea, and bowel frequency and stool consistency scores than Mesalamine treated patients. Treatment with herbal tablet alone and in combination with Mesalamine significantly reduced the stool infection. Patients treated with herbal drug alone and in combination did not report any side effects, relapse or complications while 50% patients treated with Mesalamine exhibited the relapse with

  17. Formation of hydroxyl radicals in the human lens is related to the severity of nuclear cataract

    DEFF Research Database (Denmark)

    Garner, B; Davies, Michael Jonathan; Truscott, R J

    2000-01-01

    Recent studies have identified specific hydroxylated amino acid oxidation products which strongly suggest the presence of hydroxyl radical (HO.)-damaged proteins in human cataractous lenses. In the present study, the ability of early stage (type II) and advanced (type IV) nuclear cataractous lens...

  18. Comparison of fluorescence-based techniques for the quantification of particle-induced hydroxyl radicals

    Directory of Open Access Journals (Sweden)

    Cohn Corey A

    2008-02-01

    Full Text Available Abstract Background Reactive oxygen species including hydroxyl radicals can cause oxidative stress and mutations. Inhaled particulate matter can trigger formation of hydroxyl radicals, which have been implicated as one of the causes of particulate-induced lung disease. The extreme reactivity of hydroxyl radicals presents challenges to their detection and quantification. Here, three fluorescein derivatives [aminophenyl fluorescamine (APF, amplex ultrared, and dichlorofluorescein (DCFH] and two radical species, proxyl fluorescamine and tempo-9-ac have been compared for their usefulness to measure hydroxyl radicals generated in two different systems: a solution containing ferrous iron and a suspension of pyrite particles. Results APF, amplex ultrared, and DCFH react similarly to the presence of hydroxyl radicals. Proxyl fluorescamine and tempo-9-ac do not react with hydroxyl radicals directly, which reduces their sensitivity. Since both DCFH and amplex ultrared will react with reactive oxygen species other than hydroxyl radicals and another highly reactive species, peroxynitite, they lack specificity. Conclusion The most useful probe evaluated here for hydroxyl radicals formed from cell-free particle suspensions is APF due to its sensitivity and selectivity.

  19. Testosterone 15β-hydroxylation by solvent tolerant Pseudomonas putida S12

    NARCIS (Netherlands)

    Ruijssenaars, H.J.; Sperling, E.M.G.M.; Wiegerinck, P.H.G.; Brands, F.T.L.; Wery, J.; Bont, J.A.M.de

    2007-01-01

    A steroid 15β-hydroxylating whole-cell solvent tolerant biocatalyst was constructed by expressing the Bacillus megaterium steroid hydroxylase CYP106A2 in the solvent tolerant Pseudomonas putida S12. Testosterone hydroxylation was improved by a factor 16 by co-expressing Fer, a putative Fe-S protein

  20. Study on the surface hydroxyl group on solid breeding materials by ab-initio calculations

    Energy Technology Data Exchange (ETDEWEB)

    Tanaka, Satoru; Taniguchi, Masaki [Tokyo Univ. (Japan). Faculty of Engineering

    1996-10-01

    The nature of -OH on the surface of Li{sub 2}O was analyzed with the ab-initio quantum chemical calculation technique. Calculation results showed that the stretching vibration of O-H is affected by the chemical species around the -OH. (author)

  1. Hydroxylamine as an oxygen nucleophile: substitution of sulfonamide by a hydroxyl group in benzothiazole-2-sulfonamides

    NARCIS (Netherlands)

    Kamps, J.A.G.; Belle, R.; Mecinovic, J.

    2013-01-01

    Benzothiazole-2-sulfonamides react with an excess of hydroxylamine in aqueous solutions to form 2-hydroxybenzothiazole, sulfur dioxide, and the corresponding amine. Mechanistic studies that employ a combination of structure-reactivity relationships, oxygen labeling experiments, and (in)direct

  2. Hydration of Hydroxyl and Amino Groups Examined by Molecular Dynamics and Neutron Scattering

    Czech Academy of Sciences Publication Activity Database

    Hladílková, Jana; Fischer, H. E.; Jungwirth, Pavel; Mason, Philip E.

    2015-01-01

    Roč. 119, č. 21 (2015), s. 6357-6365 ISSN 1520-6106 R&D Projects: GA ČR GBP208/12/G016 Institutional support: RVO:61388963 Keywords : neutron scattering * molecular dynamics * isopropyl alcohol * isopropylamine Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 3.187, year: 2015

  3. Impact of Micro Silica Surface Hydroxyl Groups on the Properties of Calcium Silicate Products

    DEFF Research Database (Denmark)

    Haastrup, Sonja; Jørgensen, Bianca; Yu, Donghong

    2017-01-01

    Porous calcium silicates are widely used in insulating systems for high temperature applications. In the production of porous calcium silicates, quicklime and micro silica have been utilized as key raw materials. In the reaction between SiO2 and CaO, the dissolution of SiO2 has been proven...

  4. Fast MAS 1H NMR Study of Water Adsorption and Dissociation on the (100) Surface of Ceria Nanocubes: A Fully Hydroxylated, Hydrophobic Ceria Surface

    Energy Technology Data Exchange (ETDEWEB)

    Gill, Lance [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). Chemical Sciences Division; Beste, Ariana [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). Joint Institute for Computational Sciences (JIBS); Univ. of Tennessee, Knoxville, TN (United States); Chen, Banghao [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). Chemical Sciences Division; Li, Meijun [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). Chemical Sciences Division; Mann, Amanda K. P. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). Chemical Sciences Division; Overbury, Steven H. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). Chemical Sciences Division; Hagaman, Edward W. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). Chemical Sciences Division

    2017-03-22

    1H nuclear magnetic resonance (NMR) spectroscopy was used to study hydroxylic surface species on ceria nanocubes, a crystalline, high-surface-area CeO2 that presents mostly (100) facets. Water adsorption and desorption experiments in combination with fast magic angle spinning (MAS, 20–40 kHz) 1H NMR provide high-resolution 1H spectra that allow the observation of ten resonance bands (water or hydroxyl) on or under the (100) surface. Assignments were made using a combination of adsorption and temperature-programmed desorption, quantitative spin counting, deuterium exchange, spin–lattice (T1) and spin–spin (T2) relaxation, and DFT calculations. In air, the (100) surface exists as a fully hydroxylated surface. Water adsorption and dissociation on dry ceria surfaces occur first at oxygen vacancies, but Ce3+ centers are not required since water dissociation is barrier-less on the fully oxidized surface. Surface $-$OH functionality occurs in two resolved bands representing isolated $-$OH (1 ppm) and hydrogen-bonded $-$OH (9 ppm), the latter being dominant. Deuterium exchange of surface hydroxyls with D2O does not occur under mild or forcing conditions. Despite large differences in the T1 of surface hydroxyls and physisorbed water, surface hydroxyl T1 values are independent of the presence or absence of physisorbed water, demonstrating that the protons within these two functional group pools are not in intimate contact. These observations show that, once hydroxylated, the surface $-$OH functionality preferentially forms hydrogen bonds with surface lattice oxygen, i.e., the hydroxylated (100) surface of ceria is hydrophobic. Near this surface it is energetically more favorable for physisorbed water to hydrogen bond to itself rather than to the surface. DFT calculations support this notion. Impurity Na+ remaining in incompletely washed ceria nanocubes

  5. Metabolic disposition of proguanil in extensive and poor metabolisers of S-mephenytoin 4'-hydroxylation recruited from an Indonesian population.

    OpenAIRE

    Setiabudy, R; Kusaka, M; Chiba, K; Darmansjah, I; Ishizaki, T

    1995-01-01

    1. The metabolism of proguanil (PG) was studied by measuring PG, cycloguanil (CG) and 4-chlorophenylbiguanide (CPB) in plasma and urine samples after an oral 200 mg dose of PG hydrochloride administered to 14 extensive (EMs) and 10 poor hydroxylators (PMs) of S-mephenytoin of Indonesian origin. 2. The mean ( +/- s.d.) values of the elimination half-life (t 1/2) and AUC of PG were significantly (P < 0.01) greater in the PM than in the EM group (20.6 +/- 3.1 vs 14.6 +/- 3.5 (95% confidence inte...

  6. Detecting irradiated foods: use of hydroxyl radical biomarkers

    International Nuclear Information System (INIS)

    Karam, L.R.; Simic, M.G.

    1988-01-01

    Recent legislation in the United States has increased the probability of using ionizing radiation for preserving food. The possible increased use of food irradiation in this country, in addition to current use of the technique in other countries, makes it important to develop a method whereby the extent of irradiation of foods can be determined. Both opponents and proponents of this particular food-processing technique support postirradiation dosimetry (PID) as a way to measure the extent of changes in irradiated products. To prevent tampering and alteration of the dosimeters, the best postirradiation dosimeters are those that are inherent in the product exposed to the ionizing radiation. Therefore detection of the intermediates and subsequent products arising from the interaction of ionizing radiation with biomolecules in food should be a viable means by which the irradiated status of a food sample can be determined. To be useful as biomarkers, however, the products formed by irradiation must be detectable by routine analytical methods, formed exclusively by ionizing radiation (unless formation from alternate methods can be readily determined), and stable for the duration of the expected shelf life of the food product. In this article Lisa R. Karam and Michael G. Simic of the National Institute of Standards and Technology describe methodology developed to identify the irradiated status of foods using hydroxyl radical biomarkers

  7. Constraining the Single-degenerate Channel of Type Ia Supernovae with Stable Iron-group Elements in SNR 3C 397

    Energy Technology Data Exchange (ETDEWEB)

    Dave, Pranav; Kashyap, Rahul; Fisher, Robert [Department of Physics, University of Massachusetts Dartmouth, 285 Old Westport Road, North Dartmouth, MA 02740 (United States); Timmes, Frank [School of Earth and Space Exploration, Arizona State University, Tempe, AZ 85287 (United States); Townsley, Dean [Department of Physics and Astronomy, Box 870324, University of Alabama, Tuscaloosa, AL 35487 (United States); Byrohl, Chris [Institut für Astrophysik, Georg August Universität Göttingen, Friedrich-Hund-Platz 1, D-37077 Göttingen (Germany)

    2017-05-20

    Recent Suzaku X-ray spectra of supernova remnant (SNR) 3C 397 indicate enhanced stable iron group element abundances of Ni, Mn, Cr, and Fe. Seeking to address key questions about the progenitor and explosion mechanism of 3C 397, we compute nucleosynthetic yields from a suite of multidimensional hydrodynamics models in the near-Chandrasekhar-mass, single-degenerate paradigm for Type Ia supernovae (SNe Ia). Varying the progenitor white dwarf (WD) internal structure, composition, ignition, and explosion mechanism, we find that the best match to the observed iron peak elements of 3C 397 are dense (central density ≥6 × 10{sup 9} g cm{sup −3}), low-carbon WDs that undergo a weak, centrally ignited deflagration, followed by a subsequent detonation. The amount of {sup 56}Ni produced is consistent with a normal or bright normal SNe Ia. A pure deflagration of a centrally ignited, low central density (≃2 × 10{sup 9} g cm{sup −3}) progenitor WD, frequently considered in the literature, is also found to produce good agreement with 3C 397 nucleosynthetic yields, but leads to a subluminous SN Ia event, in conflict with X-ray line width data. Additionally, in contrast to prior work that suggested a large supersolar metallicity for the WD progenitor for SNR 3C 397, we find satisfactory agreement for solar- and subsolar-metallicity progenitors. We discuss a range of implications our results have for the single-degenerate channel.

  8. A Complex Multiherbal Regimen Based on Ayurveda Medicine for the Management of Hepatic Cirrhosis Complicated by Ascites: Nonrandomized, Uncontrolled, Single Group, Open-Label Observational Clinical Study.

    Science.gov (United States)

    Patel, Manish V; Patel, Kalapi B; Gupta, Shivenarain; Michalsen, Andreas; Stapelfeldt, Elmar; Kessler, Christian S

    2015-01-01

    Hepatic cirrhosis is one of the leading causes of death worldwide, especially if complicated by ascites. This chronic condition can be related to the classical disease entity jalodara in Traditional Indian Medicine (Ayurveda). The present paper aims to evaluate the general potential of Ayurvedic therapy for overall clinical outcomes in hepatic cirrhosis complicated by ascites (HCcA). In form of a nonrandomized, uncontrolled, single group, open-label observational clinical study, 56 patients fulfilling standardized diagnostic criteria for HCcA were observed during their treatment at the P. D. Patel Ayurveda Hospital, Nadiad, India. Based on Ayurvedic tradition, a standardized treatment protocol was developed and implemented, consisting of oral administration of single and compound herbal preparations combined with purificatory measures as well as dietary and lifestyle regimens. The outcomes were assessed by measuring liver functions through specific clinical features and laboratory parameters and by evaluating the Child-Pugh prognostic grade score. After 6 weeks of treatment and a follow-up period of 18 weeks, the outcomes showed statistically significant and clinically relevant improvements. Further larger and randomized trials on effectiveness, safety, and quality of the Ayurvedic approach in the treatment of HCcA are warranted to support these preliminary findings.

  9. A single source precursor route to group 13 homo- and heterometallic oxides as highly active supports for gold-catalyzed aerobic epoxidation of trans-stilbene

    KAUST Repository

    Mishra, Shashank K.; Mendez, Violaine; Jeanneau, Erwann; Caps, Valerie; Daniè le, Sté phane

    2012-01-01

    A new Mitsubishi-type of star-shaped homoleptic derivative of indium(III), In4(mdea)6 (2, mdeaH2 = N-methyldiethanolamine) , was synthesized by the chloro-aminoalkoxo exchange reaction of a heteroleptic complex In6Cl6(mdea)6 (1) and used as a facile single source molecular precursor for the sol-gel preparation of high surface area indium oxide. Successful deposition of gold nanoparticles (1 wt.-%) of average size 3.3 nm on the above metal oxide by using HAuCl4· 3H2O afforded a highly efficient Au/In2O3 catalyst for the aerobic epoxidation of trans-stilbene at low temperature. The above single source precursor approach was further extended to obtain other group 13 homo- and heterometallic oxides, namely, α-Ga2O 3, β-Ga2O3 and Al4Ga 2O9, as highly active supports for gold catalysts. The obtained Au/M2O3 (M = Ga, In) and Au/Al4Ga 2O9 catalysts were thoroughly characterized by using several physicochemical techniques such as XRD, high resolution transmission electron microscopy (HR-TEM), energy-dispersive X-ray (EDX) spectroscopy, and X-ray photoelectron spectroscopy (XPS). A comparative study of the above catalysts for the model aerobic oxidation of stilbene in methylcyclohexane was undertaken. Highly efficient catalysts for aerobic oxidation reactions were obtained by depositing gold nanoparticles on group 13 mono- or mixed metal oxides prepared from the hydrolysis of well-characterized homo- and heterometallic N-methyldiethanolaminate derivatives. Copyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  10. A single source precursor route to group 13 homo- and heterometallic oxides as highly active supports for gold-catalyzed aerobic epoxidation of trans-stilbene

    KAUST Repository

    Mishra, Shashank K.

    2012-12-14

    A new Mitsubishi-type of star-shaped homoleptic derivative of indium(III), In4(mdea)6 (2, mdeaH2 = N-methyldiethanolamine) , was synthesized by the chloro-aminoalkoxo exchange reaction of a heteroleptic complex In6Cl6(mdea)6 (1) and used as a facile single source molecular precursor for the sol-gel preparation of high surface area indium oxide. Successful deposition of gold nanoparticles (1 wt.-%) of average size 3.3 nm on the above metal oxide by using HAuCl4· 3H2O afforded a highly efficient Au/In2O3 catalyst for the aerobic epoxidation of trans-stilbene at low temperature. The above single source precursor approach was further extended to obtain other group 13 homo- and heterometallic oxides, namely, α-Ga2O 3, β-Ga2O3 and Al4Ga 2O9, as highly active supports for gold catalysts. The obtained Au/M2O3 (M = Ga, In) and Au/Al4Ga 2O9 catalysts were thoroughly characterized by using several physicochemical techniques such as XRD, high resolution transmission electron microscopy (HR-TEM), energy-dispersive X-ray (EDX) spectroscopy, and X-ray photoelectron spectroscopy (XPS). A comparative study of the above catalysts for the model aerobic oxidation of stilbene in methylcyclohexane was undertaken. Highly efficient catalysts for aerobic oxidation reactions were obtained by depositing gold nanoparticles on group 13 mono- or mixed metal oxides prepared from the hydrolysis of well-characterized homo- and heterometallic N-methyldiethanolaminate derivatives. Copyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  11. Pure- and Mixed-Gas Permeation Properties of Highly Selective and Plasticization Resistant Hydroxyl-Diamine-Based 6FDA Polyimides for CO2/CH4 Separation

    KAUST Repository

    Alaslai, Nasser Y.; Ghanem, Bader; Alghunaimi, Fahd; Litwiller, Eric; Pinnau, Ingo

    2016-01-01

    The effect of hydroxyl functionalization on the m-phenylene diamine moiety of 6FDA dianhydride-based polyimides was investigated for gas separation applications. Pure-gas permeability coefficients of He, H2, N2, O2, CH4, and CO2 were measured at 35 °C and 2 atm. The introduction of hydroxyl groups in the diamine moiety of 6FDA-diaminophenol (DAP) and 6FDA-diamino resorcinol (DAR) polyimides tightened the overall polymer structure due to increased charge transfer complex formation compared to unfunctionalized 6FDA-m-phenylene diamine (mPDA). The BET surface areas based on nitrogen adsorption of 6FDA-DAP (54 m2g−1) and of 6FDA-DAR (45 m2g−1) were ~18% and 32% lower than that of 6FDA-mPDA (66 m2g−1). 6FDA-mPDA had a pure-gas CO2 permeability of 14 Barrer and CO2/CH4 selectivity of 70. The hydroxyl-functionalized polyimides 6FDA-DAP and 6FDA-DAR exhibited very high pure-gas CO2/CH4 selectivities of 92 and 94 with moderate CO2 permeability of 11 and 8 Barrer, respectively. It was demonstrated that hydroxyl-containing polyimide membranes maintained very high CO2/CH4 selectivity (~ 75 at CO2 partial pressure of 10 atm) due to CO2 plasticization resistance when tested under high-pressure mixed-gas conditions. Functionalization with hydroxyl groups may thus be a promising strategy towards attaining highly selective polyimides for economical membrane-based natural gas sweetening.

  12. Pure- and Mixed-Gas Permeation Properties of Highly Selective and Plasticization Resistant Hydroxyl-Diamine-Based 6FDA Polyimides for CO2/CH4 Separation

    KAUST Repository

    Alaslai, Nasser Y.

    2016-01-05

    The effect of hydroxyl functionalization on the m-phenylene diamine moiety of 6FDA dianhydride-based polyimides was investigated for gas separation applications. Pure-gas permeability coefficients of He, H2, N2, O2, CH4, and CO2 were measured at 35 °C and 2 atm. The introduction of hydroxyl groups in the diamine moiety of 6FDA-diaminophenol (DAP) and 6FDA-diamino resorcinol (DAR) polyimides tightened the overall polymer structure due to increased charge transfer complex formation compared to unfunctionalized 6FDA-m-phenylene diamine (mPDA). The BET surface areas based on nitrogen adsorption of 6FDA-DAP (54 m2g−1) and of 6FDA-DAR (45 m2g−1) were ~18% and 32% lower than that of 6FDA-mPDA (66 m2g−1). 6FDA-mPDA had a pure-gas CO2 permeability of 14 Barrer and CO2/CH4 selectivity of 70. The hydroxyl-functionalized polyimides 6FDA-DAP and 6FDA-DAR exhibited very high pure-gas CO2/CH4 selectivities of 92 and 94 with moderate CO2 permeability of 11 and 8 Barrer, respectively. It was demonstrated that hydroxyl-containing polyimide membranes maintained very high CO2/CH4 selectivity (~ 75 at CO2 partial pressure of 10 atm) due to CO2 plasticization resistance when tested under high-pressure mixed-gas conditions. Functionalization with hydroxyl groups may thus be a promising strategy towards attaining highly selective polyimides for economical membrane-based natural gas sweetening.

  13. Detection analysis of surface hydroxyl active sites and simulation calculation of the surface dissociation constants of aqueous diatomite suspensions

    International Nuclear Information System (INIS)

    Ma, Shu-Cui; Wang, Zhi-Gang; Zhang, Ji-Lin; Sun, De-Hui; Liu, Gui-Xia

    2015-01-01

    Highlights: • To examine surface hydroxyl functional groups of the calcined diatomite by TGA-DSC, FTIR, and XPS. • To calculate the optimized log K 1 , log K 2 and log C values and the surface species distribution of each surface reactive site using ProtoFit and PHREEQC, respectively. - Abstract: The surface properties of the diatomite were investigated using nitrogen adsorption/deadsorption isotherms, TG-DSC, FTIR, and XPS, and surface protonation–deprotonation behavior was determined by continuous acid–base potentiometric titration technique. The diatomite sample with porous honeycomb structure has a BET specific surface area of 10.21 m 2 /g and large numbers of surface hydroxyl functional groups (i.e. ≡Si-OH, ≡Fe-OH, and ≡Al-OH). These surface hydroxyls can be protonated or deprotonated depending on the pH of the suspension. The experimental potentiometric data in two different ionic strength solutions (0.1 and 0.05 mol/L NaCl) were fitted using ProtoFit GUI V2.1 program by applying diffuse double layer model (DLM) with three amphoteric sites and minimizing the sum of squares between a dataset derivative function and a model derivative function. The optimized surface parameters (i.e. surface dissociation constants (log K 1 , log K 2 ) and surface site concentrations (log C)) of the sample were obtained. Based on the optimized surface parameters, the surface species distribution was calculated using Program-free PHREEQC 3.1.2. Thus, this work reveals considerable new information about surface protonation–deprotonation processes and surface adsorptive behaviors of the diatomite, which helps us to effectively use the cheap and cheerful diatomite clay adsorbent

  14. Detection analysis of surface hydroxyl active sites and simulation calculation of the surface dissociation constants of aqueous diatomite suspensions

    Energy Technology Data Exchange (ETDEWEB)

    Ma, Shu-Cui [State Key Laboratory of Rare Earth Resource Utilization, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun 130022 (China); Key Laboratory of Applied Chemistry and Nanotechnology at Universities of Jilin Province, Changchun University of Science and Technology, Changchun 130022 (China); Wang, Zhi-Gang [State Key Laboratory of Rare Earth Resource Utilization, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun 130022 (China); Zhang, Ji-Lin, E-mail: zjl@ciac.ac.cn [State Key Laboratory of Rare Earth Resource Utilization, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun 130022 (China); Sun, De-Hui [Changchun Institute Technology, Changchun 130012 (China); Liu, Gui-Xia, E-mail: liuguixia22@163.com [Key Laboratory of Applied Chemistry and Nanotechnology at Universities of Jilin Province, Changchun University of Science and Technology, Changchun 130022 (China)

    2015-02-01

    Highlights: • To examine surface hydroxyl functional groups of the calcined diatomite by TGA-DSC, FTIR, and XPS. • To calculate the optimized log K{sub 1}, log K{sub 2} and log C values and the surface species distribution of each surface reactive site using ProtoFit and PHREEQC, respectively. - Abstract: The surface properties of the diatomite were investigated using nitrogen adsorption/deadsorption isotherms, TG-DSC, FTIR, and XPS, and surface protonation–deprotonation behavior was determined by continuous acid–base potentiometric titration technique. The diatomite sample with porous honeycomb structure has a BET specific surface area of 10.21 m{sup 2}/g and large numbers of surface hydroxyl functional groups (i.e. ≡Si-OH, ≡Fe-OH, and ≡Al-OH). These surface hydroxyls can be protonated or deprotonated depending on the pH of the suspension. The experimental potentiometric data in two different ionic strength solutions (0.1 and 0.05 mol/L NaCl) were fitted using ProtoFit GUI V2.1 program by applying diffuse double layer model (DLM) with three amphoteric sites and minimizing the sum of squares between a dataset derivative function and a model derivative function. The optimized surface parameters (i.e. surface dissociation constants (log K{sub 1}, log K{sub 2}) and surface site concentrations (log C)) of the sample were obtained. Based on the optimized surface parameters, the surface species distribution was calculated using Program-free PHREEQC 3.1.2. Thus, this work reveals considerable new information about surface protonation–deprotonation processes and surface adsorptive behaviors of the diatomite, which helps us to effectively use the cheap and cheerful diatomite clay adsorbent.

  15. Measurement of hydroxyl radical production in ultrasonic aqueous solutions by a novel chemiluminescence method.

    Science.gov (United States)

    Hu, Yufei; Zhang, Zhujun; Yang, Chunyan

    2008-07-01

    Measurement methods for ultrasonic fields are important for reasons of safety. The investigation of an ultrasonic field can be performed by detecting the yield of hydroxyl radicals resulting from ultrasonic cavitations. In this paper, a novel method is introduced for detecting hydroxyl radicals by a chemiluminescence (CL) reaction of luminol-hydrogen peroxide (H2O2)-K5[Cu(HIO6)2](DPC). The yield of hydroxyl radicals is calculated directly by the relative CL intensity according to the corresponding concentration of H2O2. This proposed CL method makes it possible to perform an in-line and real-time assay of hydroxyl radicals in an ultrasonic aqueous solution. With flow injection (FI) technology, this novel CL reaction is sensitive enough to detect ultra trace amounts of H2O2 with a limit of detection (3sigma) of 4.1 x 10(-11) mol L(-1). The influences of ultrasonic output power and ultrasonic treatment time on the yield of hydroxyl radicals by an ultrasound generator were also studied. The results indicate that the amount of hydroxyl radicals increases with the increase of ultrasonic output power (< or = 15 W mL(-1)). There is a linear relationship between the time of ultrasonic treatment and the yield of H2O2. The ultrasonic field of an ultrasonic cleaning baths has been measured by calculating the yield of hydroxyl radicals.

  16. Pertuzumab for the Neoadjuvant Treatment of Early-Stage HER2-Positive Breast Cancer: An Evidence Review Group Perspective of a NICE Single Technology Appraisal.

    Science.gov (United States)

    Squires, Hazel; Pandor, Abdullah; Thokala, Praveen; Stevens, John W; Kaltenthaler, Eva; Clowes, Mark; Coleman, Robert; Wyld, Lynda

    2018-01-01

    As part of its single technology appraisal process, the National Institute for Health and Care Excellence invited the manufacturer of pertuzumab (Perjeta ® ; Roche Products Limited) to submit evidence of its clinical and cost- effectiveness for the neoadjuvant treatment of women with high-risk, early-stage, HER2-positive breast cancer when used in combination with trastuzumab and chemotherapy. High-risk women included those with locally advanced (including inflammatory) breast cancer and women with high-risk early-stage breast cancer (classified as T2/3 or N1). The School of Health and Related Research Technology Appraisal Group at the University of Sheffield was commissioned to act as the independent Evidence Review Group. This article presents the critical review of the company's submission by the Evidence Review Group and the outcome of the National Institute for Health and Care Excellence guidance. The clinical data were mainly taken from a phase II, randomised, open-label, active controlled study (NeoSphere), which reported a significant advantage in terms of pathological complete response rates of pertuzumab in combination with trastuzumab and chemotherapy, compared with trastuzumab alone with chemotherapy (45.8 vs. 29.0%, p = 0.0141). The company did not make any indirect comparisons. A meta-analysis of 12 neoadjuvant studies investigating the relationship between pathological complete response and event-free survival was used to extrapolate the outcomes reported in the NeoSphere study. A cardiac safety study (TRYPHAENA) demonstrated the safety of pertuzumab. The company undertook a model-based economic evaluation of neoadjuvant pertuzumab plus trastuzumab and docetaxel compared with neoadjuvant trastuzumab and docetaxel over a lifetime horizon from the National Health Service and Personal Social Services perspective. The probabilistic incremental cost-effectiveness ratio was estimated to be £20,104 per quality-adjusted life-year gained for pertuzumab

  17. Hydroxylation of the herbicide isoproturon by fungi isolated from agricultural soil.

    Science.gov (United States)

    Rønhede, Stig; Jensen, Bo; Rosendahl, Søren; Kragelund, Birthe B; Juhler, René K; Aamand, Jens

    2005-12-01

    Several asco-, basidio-, and zygomycetes isolated from an agricultural field were shown to be able to hydroxylate the phenylurea herbicide isoproturon [N-(4-isopropylphenyl)-N',N'-dimethylurea] to N-(4-(2-hydroxy-1-methylethyl)phenyl)-N',N'-dimethylurea and N-(4-(1-hydroxy-1-methylethyl)phenyl)-N',N'-dimethylurea. Bacterial metabolism of isoproturon has previously been shown to proceed by an initial demethylation to N-(4-isopropylphenyl)-N'-methylurea. In soils, however, hydroxylated metabolites have also been detected. In this study we identified fungi as organisms that potentially play a major role in the formation of these hydroxylated metabolites in soils treated with isoproturon. Isolates of Mortierella sp. strain Gr4, Phoma cf. eupyrena Gr61, and Alternaria sp. strain Gr174 hydroxylated isoproturon at the first position of the isopropyl side chain, yielding N-(4-(2-hydroxy-1-methylethyl)phenyl)-N',N'-dimethylurea, while Mucor sp. strain Gr22 hydroxylated the molecule at the second position, yielding N-(4-(1-hydroxy-1-methylethyl)phenyl)-N',N'-dimethylurea. Hydroxylation was the dominant mode of isoproturon transformation in these fungi, although some cultures also produced traces of the N-demethylated metabolite N-(4-isopropylphenyl)-N'-methylurea. A basidiomycete isolate produced a mixture of the two hydroxylated and N-demethylated metabolites at low concentrations. Clonostachys sp. strain Gr141 and putative Tetracladium sp. strain Gr57 did not hydroxylate isoproturon but N demethylated the compound to a minor extent. Mortierella sp. strain Gr4 also produced N-(4-(2-hydroxy-1-methylethyl)phenyl)-N'-methylurea, which is the product resulting from combined N demethylation and hydroxylation.

  18. Hydroxyl temperature and intensity measurements during noctilucent cloud displays

    Directory of Open Access Journals (Sweden)

    M. J. Taylor

    1995-10-01

    Full Text Available Two Fourier transform spectrometers have been used to investigate the properties of the near-infrared hydroxyl (OH nightglow emission under high-latitude summertime conditions and any association with noctilucent clouds (NLCs. The measurements were made from Poker Flat Research Range, Alaska (65.1°N, 147.5°W, during August 1986. Simultaneous photographic observations of the northern twilight sky were made from Gulkana, Alaska (62.2°N, 145.5°W, approximately 340 km to the south to establish the presence of NLCs over the spectrometer site. Data exhibiting significant short-term variations in the relative intensity (as much as 50–100% and rotational temperature (typically 5–15 K were recorded on six occasions when NLCs were observed. Joint measurements were also obtained on several "cloud-free" nights. No obvious relationship was found linking the mean OH intensity or its variation with the occurrence of NLCs. However, a clear tendency was found for the mean OH temperature to be lower on NLC nights than on cloud-free nights. In particular, a significant fraction of the OH(3–1 band spectra recorded by each instrument (16–57% exhibited temperatures below ~154 K on NLC nights compared with <3% on cloud-free nights. This result is qualitatively consistent with current models for ice particle nucleation and growth, but the mean OH temperature on NLC nights (~156 K was significantly higher than would be expected for long-term particle growth in this region. These observations raise questions concerning the expected proximity of the high-latitude, summertime OH layer and the NLC growth region.

  19. Hydroxyl temperature and intensity measurements during noctilucent cloud displays

    Directory of Open Access Journals (Sweden)

    M. J. Taylor

    Full Text Available Two Fourier transform spectrometers have been used to investigate the properties of the near-infrared hydroxyl (OH nightglow emission under high-latitude summertime conditions and any association with noctilucent clouds (NLCs. The measurements were made from Poker Flat Research Range, Alaska (65.1°N, 147.5°W, during August 1986. Simultaneous photographic observations of the northern twilight sky were made from Gulkana, Alaska (62.2°N, 145.5°W, approximately 340 km to the south to establish the presence of NLCs over the spectrometer site. Data exhibiting significant short-term variations in the relative intensity (as much as 50–100% and rotational temperature (typically 5–15 K were recorded on six occasions when NLCs were observed. Joint measurements were also obtained on several "cloud-free" nights. No obvious relationship was found linking the mean OH intensity or its variation with the occurrence of NLCs. However, a clear tendency was found for the mean OH temperature to be lower on NLC nights than on cloud-free nights. In particular, a significant fraction of the OH(3–1 band spectra recorded by each instrument (16–57% exhibited temperatures below ~154 K on NLC nights compared with <3% on cloud-free nights. This result is qualitatively consistent with current models for ice particle nucleation and growth, but the mean OH temperature on NLC nights (~156 K was significantly higher than would be expected for long-term particle growth in this region. These observations raise questions concerning the expected proximity of the high-latitude, summertime OH layer and the NLC growth region.

  20. Hydroxyl radical modify amino acids and prevent E. coli growth

    International Nuclear Information System (INIS)

    Zhang, Y.; Davies, K.J.A.

    1986-01-01

    The authors report that hydroxyl radical (/sup ./OH) damage to amino acids (AA) affects their incorporation into E. coli proteins. Modification of AA (Try, Trp, Met, Cys, His, Lys, Asn, Gln) by /sup ./OH was achieved by exposure to 60 Co radiation (1-100 krads at 600 rads/min) in N 2 O saturated water. Following exposure to /sup ./OH, the modified AA were added to suspensions of 8 AA requiring E. coli mutants in M9 medium + glucose. Mutants incubated with the /sup ./OH modified AA underwent less growth than those incubated with unmodified AA; with a declining exponential relationship between /sup ./OH exposure of AA and cell growth. The sensitivity of each AA to modification by /sup ./OH was as follows: Tyr > Trp > Met > Cys > His > Lys > Asn > Gln. Essentially the same pattern was observed for inhibition of mutant growth, which was proportional to the concentration of remaining unmodified (i.e. native) AA. Furthermore, cell growth was restored to normal levels by replenishment of native AA. When AA were irradiated at 50μM and then diluted to concentrations expected to support exponential growth (different for each AA) the radiation doses at which mutant growth was inhibited by 63% were as follows (in krad): Tyr 41, Trp 48, Met 53, Cys 56, His 57, Lys 68, Asn 80, Gln 116. /sup ./OH-modified 3 H-Trp was not a substrate for protein synthesis in Trp requiring mutants but was taken up by the cells. Modified Trp was also not incorporated in cell-free synthesis experiments. No toxicity was observed when wild type E. coli, in M9 medium + glucose, were supplemented with any of the/sup ./OH-modified AA. Thus /sup ./OH-modified AA do not support E. coli growth

  1. Measurement of hydroxylated PCB metabolites for Slovakia maternal blood serums

    Energy Technology Data Exchange (ETDEWEB)

    Park, J.S.; Athanasiadou, M; Bergman, A. [Stockholm Univ., Stockholm (Sweden); Charles, J.; Zhao, G.; Hertz-Picciotto, I. [California Univ., Sacramento, CA (United States); Petrik, J.; Kocan, A; Trnovec, T. [Bratislava Inst. of Preventive and Clinical Medicine, Bratislava (Slovakia)

    2005-07-01

    Although it is known that polychlorinated biphenyls (PCBs) have adverse impacts on human health, it is not clear if human health impacts are caused by the PCBs or their related hydroxylated (OH) PCB metabolite compounds. This study measured OH-PCB metabolites in the maternal blood serum specimens from the Svidnik and Michalovce areas in eastern Slovakia where PCBs were intensively produced and inadequately disposed. The aim of the study was to characterize and quantify levels of specific OH-PCB metabolites in Slovakian maternal serums exposed to high environmental PCB levels. All specimens were analyzed for PCBs, and a subset of the samples was analyzed for OH-PCB metabolites. The Wallenburg blood extraction method was adopted to separate the OH-PCBs from the blood serums. Final eluates and calibration standards were spiked with PCB209 as an injection standard before gas chromatography (GC) analysis. OH-PCBs in the samples range from 75{+-}9 per cent to 101{+-}11 per cent. Median concentrations of OH-PCB metabolites of Michalovce samples were approximately twice as high as for the Svidnik samples. Concentrations of OH-PCBs of Michalovce blood samples were comparable to samples obtained from northern Canadian female Inuit and Faroe Island females, and were considered to be among the highest OH-PCB concentrations obtained in human blood. It was concluded that further research is needed to understand the placental transfer of OH-PCBs to the fetus, as well as epidemiological approaches to determine the relationship between the exposure of OH-PCB metabolites and child development. 12 refs., 2 figs.

  2. Thin film complementary metal oxide semiconductor (CMOS) device using a single-step deposition of the channel layer

    KAUST Repository

    Nayak, Pradipta K.

    2014-04-14

    We report, for the first time, the use of a single step deposition of semiconductor channel layer to simultaneously achieve both n-and p-type transport in transparent oxide thin film transistors (TFTs). This effect is achieved by controlling the concentration of hydroxyl groups (OH-groups) in the underlying gate dielectrics. The semiconducting tin oxide layer was deposited at room temperature, and the maximum device fabrication temperature was 350C. Both n and p-type TFTs showed fairly comparable performance. A functional CMOS inverter was fabricated using this novel scheme, indicating the potential use of our approach for various practical applications.

  3. The tyrosine B10 hydroxyl is crucial for oxygen avidity of Ascaris hemoglobin.

    Science.gov (United States)

    Kloek, A P; Yang, J; Mathews, F S; Frieden, C; Goldberg, D E

    1994-01-28

    The parasitic nematode Ascaris suum has a gene encoding a two-domain hemoglobin with remarkable oxygen avidity. The strong interaction with oxygen is a consequence of a particularly slow oxygen off-rate. The single polypeptide chain consists of two domains, each of which can be expressed separately in Escherichia coli as a globin-like protein exhibiting oxygen binding characteristics comparable with the native molecule. Site-directed mutagenesis was performed on the gene segment encoding domain one. The E7 position, involved in forming a hydrogen bond with the liganded oxygen in vertebrate globins, is a glutamine in both Ascaris domains. Conversion of this residue to leucine or alanine produced a hemoglobin variant with an oxygen off-rate 5- or 60-fold faster than that of unaltered domain one. Replacement of the tyrosine B10 with either phenylalanine or leucine (as found in vertebrate globins) yielded hemoglobin mutants with oxygen off-rates 280- or 570-fold faster, approaching rates found with vertebrate myoglobins. The data suggest that the distal glutamine hydrogen bonds with the liganded oxygen and that the tyrosine B10 hydroxyl contributes an additional hydrogen bond that appears substantially responsible for the extreme oxygen avidity of Ascaris hemoglobin.

  4. Microwave-induced electrophilic addition of single-walled carbon nanotubes with alkylhalides

    Energy Technology Data Exchange (ETDEWEB)

    Xu Yang [Faculty of Materials Science and Engineering, Hubei University, Wuhan 430062 (China); Wang Xianbao [Faculty of Materials Science and Engineering, Hubei University, Wuhan 430062 (China); Ministry-of-Education, Key Laboratory for the Synthesis and Application of Organic Functional Molecules, Hubei University, Wuhan 430062 (China)], E-mail: wxb@hubu.edu.cn; Tian Rong; Li Shaoqing; Wan Li; Li Mingjian; You Haijun; Li Qin [Faculty of Materials Science and Engineering, Hubei University, Wuhan 430062 (China); Wang Shimin [Faculty of Materials Science and Engineering, Hubei University, Wuhan 430062 (China); Ministry-of-Education, Key Laboratory for the Synthesis and Application of Organic Functional Molecules, Hubei University, Wuhan 430062 (China)

    2008-02-15

    We report the microwave-induced electrophilic addition of single-walled carbon nanotubes (SWNTs) with alkylhalides using Lewis acid as a catalyst followed by hydrolysis. The reaction results in the attachment of alkyl and hydroxyl groups to the surface of the nanotubes. This rapid and high-energy microwave radiation is found to be highly efficient for this reaction, which only needs as low as several minutes. The resulting nanotubes were characterized with FTIR, UV-vis-NIR, Raman, TGA, TEM and AFM. It demonstrates that iodo-alkanes show higher reaction activity with SWNTs than chloro- and bromo-alkanes.

  5. Activation of PVDF membranes through facile hydroxylation of the polymeric dope

    KAUST Repository

    Al-Gharabli, Samer; Mavukkandy, Musthafa O.; Kujawa, Joanna; Nunes, Suzana Pereira; Arafat, Hassan A.

    2017-01-01

    A method comprising a two-step alkali/acid treatment of poly (vinylidene fluoride) (PVDF) polymer is developed for the fabrication of flat-sheet PVDF membranes functionalized with labile hydroxyl groups. This method involves the application of a short-duration modification in alkali medium (5% KOH). Extensive characterizations were performed on the prepared membranes. Modification of the polymer altered the crystallinity of the PVDF from a mixture of both α and β phases to a predominant β phase. Lower work of adhesion of the modified membrane indicated the formation of a more hydrophobic and wetting-resistant membrane surface. Centrifugation of the polymer dope after the modification had a pronounced impact on the properties of the resultant membranes. This protocol could be utilized in fine-tuning the properties of PVDF membranes for various target-specific applications such as membrane distillation. This method can also be used in functionalizing PVDF membranes further by exploiting the labile –OH group present on the membrane surface.

  6. Activation of PVDF membranes through facile hydroxylation of the polymeric dope

    KAUST Repository

    Al-Gharabli, Samer

    2017-10-30

    A method comprising a two-step alkali/acid treatment of poly (vinylidene fluoride) (PVDF) polymer is developed for the fabrication of flat-sheet PVDF membranes functionalized with labile hydroxyl groups. This method involves the application of a short-duration modification in alkali medium (5% KOH). Extensive characterizations were performed on the prepared membranes. Modification of the polymer altered the crystallinity of the PVDF from a mixture of both α and β phases to a predominant β phase. Lower work of adhesion of the modified membrane indicated the formation of a more hydrophobic and wetting-resistant membrane surface. Centrifugation of the polymer dope after the modification had a pronounced impact on the properties of the resultant membranes. This protocol could be utilized in fine-tuning the properties of PVDF membranes for various target-specific applications such as membrane distillation. This method can also be used in functionalizing PVDF membranes further by exploiting the labile –OH group present on the membrane surface.

  7. Endoscopic treatment of vesicoureteral reflux using calcium hydroxyl apatite in dogs

    Directory of Open Access Journals (Sweden)

    Tavakoli Azin

    2011-01-01

    Full Text Available Abstract Background Injection of biomaterial to suburetral region, using minimally invasive procedure, has become an interesting topic for urologists to treat vesicoureteral reflux. The objective of this study was to evaluate the feasibility of injecting newly introduced calcium hydroxyl apatite to suburetral region, for treating an experimentally induced vesicoureteral reflux in dogs. Findings Bilateral vesicoureteral refluxed (VUR mixed breed dogs (n = 12; 10-15 kg live weight, 3-6 months of age were selected for this study. The presence and grade of the reflux were determined using cystography. Accordingly, 6 dogs displayed grade 1 & 2 and the other 6 showed grade 3 & 4 bilateral VUR. Every single dog, with bilateral VUR, underwent endoscopic treatment and received an injection of calcium hydroxyl apatite (an Iranian made product into the left (treated side and an injection of the similar volume of normal saline in to the right (control side subureteric space. One week, 3 and 6 months after treatment, cystography was performed. On each occasion, 4 dogs were euthanized by gas inhalation and biopsy samples were collected for histopathological study from ureter, bladder, kidney, lung and spleen in order to investigate the biomaterial migration into different organs. Data were analyzed using Chi-squared test. In control sides, radiographs confirmed the same grade of VUR, found at the initiation of the study. VUR was resolved in 100% (6/6 of Grade 1 & 2 and 83.33% (5/6 of Grade 3 & 4 in treated side. Therefore, the total success rate of this study was 91.67% (11/12. Macroscopic examination of the vesicouretral region of the treated side revealed a firm and consistent biomaterial mass at the site of injection. Histological findings confirmed inflammation at treated side. In contrast, there was no tissue reaction on control side. There was no evidence for biomaterial migration in macroscopic and microscopic observations in this study. Conclusion In

  8. In vivo hydroxylation of 3H-acetanilide--evaluation of a new radiospirometric method in the rat.

    Science.gov (United States)

    Toutoungi, M; Bieri, H U; Huguenin, P; Karlaganis, G; Zeng, T T; Bircher, J

    1983-12-01

    The proposed in vivo methodology for the investigation of hydroxylation rates consists of of the i.v. administration of tritiated substrates and the collection of tritiated water (HTO) from exhaled air as a measure of HTO accumulation in body water. Specifically, HTO was assessed in exhaled water after i.v. administration of 3H-acetanilide. Over a wide range the half lives of accumulation of HTO in exhaled water (T50) were almost identical with the half lives of elimination of 3H-acetanilide in blood, evaluated by an inverse isotope dilution method (r = 0.96, N = 18). Average T50 amounted to 29 min in controls, was reduced to 20 min after enzyme induction by phenobarbital or 3-methylcholanthrene, and prolonged to 45, 46 and 66 min after bile duct ligation, portacaval shunt and a single dose of ethanol, respectively. It is concluded that the chosen pharmacokinetic approach corrects for the NIH-shift and the results adequately reflect changes in acetanilide hydroxylation related to enzyme induction or inhibition and to liver pathology.

  9. Infrared spectroscopy of flavones and flavonols. Reexamination of the hydroxyl and carbonyl vibrations in relation to the interactions of flavonoids with membrane lipids

    Science.gov (United States)

    Baranović, Goran; Šegota, Suzana

    2018-03-01

    Detailed vibrational assignments for twelve flavonoids (seven flavones (flavone, 3- and 5-hydroxyflavone, chrysin, apigenin, fisetin and luteolin) and five flavonols (galangin, kaempferol, quercetin, morin and myricetin)) have been made based on own and reported experimental data and calculations at the B3LYP/6-31 + G(d,p) level of theory. All the molecules are treated in a uniform way by using the same set of redundancy-free set of internal coordinates. A generalized harmonic mode mixing is used to corroborate the vibrational characteristics of this important class of molecules. Each flavonoid molecule can be treated from the vibrational point of view as made of relatively weakly coupled chromone and phenyl part. It has been shown that the strongest band around 1600 cm- 1 need not be attributable to the Cdbnd O stretching. The way the vibrations of any of the hydroxyl groups are mixed with ring vibrations and vibrations of other neighboring hydroxyl groups is rather involved. This imposes severe limitations on any attempt to describe normal modes of a flavonol in terms of hydroxyl or carbonyl group vibrations. The role of water molecules in the appearance of flavonoid IR spectra is emphasized. Knowing for the great affinity of phosphate groups in lipids towards water, the immediate consequence is a reasonable assumption that flavonoid lipid interactions is mediated by water.

  10. Scattering of State-Selected and Oriented Hydroxyl Radicals by Halogen Hydrides and Xenon

    NARCIS (Netherlands)

    Moise, A.V.

    2007-01-01

    The interaction of the OH radical with atoms and other molecules is relevant for many physical and chemical processes involved in atmospheric, combustion and interstellar chemistry. Various experimental and theoretical studies have revealed information concerning the interaction of the hydroxyl

  11. Atmospheric hydroxyl radical production from electronically excited NO2 and H2O.

    Science.gov (United States)

    Li, Shuping; Matthews, Jamie; Sinha, Amitabha

    2008-03-21

    Hydroxyl radicals are often called the "detergent" of the atmosphere because they control the atmosphere's capacity to cleanse itself of pollutants. Here, we show that the reaction of electronically excited nitrogen dioxide with water can be an important source of tropospheric hydroxyl radicals. Using measured rate data, along with available solar flux and atmospheric mixing ratios, we demonstrate that the tropospheric hydroxyl contribution from this source can be a substantial fraction (50%) of that from the traditional O(1D) + H2O reaction in the boundary-layer region for high solar zenith angles. Inclusion of this chemistry is expected to affect modeling of urban air quality, where the interactions of sunlight with emitted NOx species, volatile organic compounds, and hydroxyl radicals are central in determining the rate of ozone formation.

  12. Hydroxylation of benzene to phenol over magnetic recyclable nanostructured CuFe mixed-oxide catalyst

    CSIR Research Space (South Africa)

    Makgwane, PR

    2015-03-01

    Full Text Available A highly active and magnetically recyclable nanostructured copper–iron oxide (CuFe) catalyst has been synthesized for hydroxylation of benzene to phenol under mild reaction conditions. The obtained catalytic results were correlated with the catalyst...

  13. MLS/Aura L2 Hydroxyl (OH) Mixing Ratio V002

    Data.gov (United States)

    National Aeronautics and Space Administration — ML2OH is the EOS Aura Microwave Limb Sounder (MLS) standard product for hydroxyl derived from radiances measured by the THz radiometer. The current version is 2.2....

  14. Hydroxylation of the Herbicide Isoproturon by Fungi Isolated from Agricultural Soil

    OpenAIRE

    Rønhede, Stig; Jensen, Bo; Rosendahl, Søren; Kragelund, Birthe B.; Juhler, René K.; Aamand, Jens

    2005-01-01

    Several asco-, basidio-, and zygomycetes isolated from an agricultural field were shown to be able to hydroxylate the phenylurea herbicide isoproturon [N-(4-isopropylphenyl)-N′,N′-dimethylurea] to N-(4-(2-hydroxy-1-methylethyl)phenyl)-N′,N′-dimethylurea and N-(4-(1-hydroxy-1-methylethyl)phenyl)-N′,N′-dimethylurea. Bacterial metabolism of isoproturon has previously been shown to proceed by an initial demethylation to N-(4-isopropylphenyl)-N′-methylurea. In soils, however, hydroxylated metaboli...

  15. 4-Substituted-2-Methoxyphenol: Suitable Building Block to Prepare New Bioactive Natural-like Hydroxylated Biphenyls.

    Science.gov (United States)

    Dettori, Maria Antonietta; Fabbri, Davide; Pisano, Marina; Rozzo, Carla; Palmieri, Giuseppe; Dess, Alessandro; Dallocchio, Roberto; Delogu, Giovanna

    2015-02-01

    A small collection of eugenol- and curcumin-analog hydroxylated biphenyls was prepared by straightforward methods starting from natural 4-substituted-2-methoxyphenols and their antitumoral activity was evaluated in vitro . Two curcumin-biphenyl derivatives showed interesting growth inhibitory activities on different malignant melanoma cell lines with IC 50 ranging from 13 to 1 µM. Preliminary molecular modeling studies were carried out to evaluate conformations and dihedral angles suitable for antiproliferative activity in hydroxylated biphenyls bearing a side aliphatic chain.

  16. Proline-hydroxylated hypoxia-inducible factor 1α (HIF-1α upregulation in human tumours.

    Directory of Open Access Journals (Sweden)

    Cameron E Snell

    Full Text Available The stabilisation of HIF-α is central to the transcriptional response of animals to hypoxia, regulating the expression of hundreds of genes including those involved in angiogenesis, metabolism and metastasis. HIF-α is degraded under normoxic conditions by proline hydroxylation, which allows for recognition and ubiquitination by the von-Hippel-Lindau (VHL E3 ligase complex. The aim of our study was to investigate the posttranslational modification of HIF-1α in tumours, to assess whether there are additional mechanisms besides reduced hydroxylation leading to stability. To this end we optimised antibodies against the proline-hydroxylated forms of HIF-1α for use in formalin fixed paraffin embedded (FFPE immunohistochemistry to assess effects in tumour cells in vivo. We found that HIF-1α proline-hydroxylated at both VHL binding sites (Pro402 and Pro564, was present in hypoxic regions of a wide range of tumours, tumour xenografts and in moderately hypoxic cells in vitro. Staining for hydroxylated HIF-1α can identify a subset of breast cancer patients with poorer prognosis and may be a better marker than total HIF-1α levels. The expression of unhydroxylated HIF-1α positively correlates with VHL in breast cancer suggesting that VHL may be rate-limiting for HIF degradation. Our conclusions are that the degradation of proline-hydroxylated HIF-1α may be rate-limited in tumours and therefore provides new insights into mechanisms of HIF upregulation. Persistence of proline-hydroxylated HIF-1α in perinecrotic areas suggests there is adequate oxygen to support prolyl hydroxylase domain (PHD activity and proline-hydroxylated HIF-1α may be the predominant form associated with the poorer prognosis that higher levels of HIF-1α confer.

  17. The Effect of Hydroxylated Fullerene Nanoparticles on Antioxidant Defense System in Brain Ischemia Rat

    Directory of Open Access Journals (Sweden)

    2017-05-01

    Full Text Available Background and Objectives: According to the previous findings, brain ischemia attenuates the brain antioxidant defense system. This study aimed to investigate the effect of hydroxylated fullerene nanoparticle on antioxidant defense system in ischemic brain rat. Methods: In this Experimental study, rats were divided into three groups (n=6 in each group: sham, ischemic control, and ischemic treatment group. Brain ischemia was induced by middle cerebral artery (MCA occlusion for 90 minutes followed by a 24-hour reperfusion. Ischemic treatment animals received fullerene nanoparticles intraperitoneally at a dose of 10mg/kg immediately after the end of MCA occlusion. After 24-h reperfusion period, brain catalase and superoxide dismutase (SOD, and glutathione activities were assessed by biochemical methods. The data were analyzed using one-way ANOVA and Tukey post-hoc test. Results: The mean glutathione level and catalase and SOD activities in sham animals were 1±0.18%, 1±0.20%, and 1±0.04%, respectively. Induction of brain ischemia decreased the value of glutathione level and catalase and SOD activities in control ischemic rats and their values were obtained to be 0.55±0.09%, 0.44±0.05%, and 0.86±0.02%, respectively. Fullerene significantly increased the activities of catalase (0.93±0.29% and SOD (1.33±0.22% in ischemic treatment group compared to ischemic control rats, but did not change the glutathione level (0.52±0.25%. Conclusion: The results of this study showed that treatment with fullerene nanoparticles improves the brain antioxidant defense system, which is weakened during brain ischemia, through increasing catalase and SOD activities.

  18. CATALYTIC PERFORMANCES OF Fe2O3/TS-1 CATALYST IN PHENOL HYDROXYLATION REACTION

    Directory of Open Access Journals (Sweden)

    Didik Prasetyoko

    2010-07-01

    Full Text Available Hydroxylation reaction of phenol into diphenol, such as hydroquinone and catechol, has a great role in many industrial applications. Phenol hydroxylation reaction can be carried out using Titanium Silicalite-1 (TS-1 as catalyst and H2O2 as an oxidant. TS-1 catalyst shows high activity and selectivity for phenol hydroxylation reaction. However, its hydrophobic sites lead to slow H2O2 adsorption toward the active site of TS-1. Consequently, the reaction rate of phenol hydroxylation reaction is tends to be low. Addition of metal oxide Fe2O3 enhanced hydrophilicity of TS-1 catalyst. Liquid phase catalytic phenol hydroxylation using hydrogen peroxide as oxidant was carried out over iron (III oxide-modified TS-1 catalyst (Fe2O3/TS-1, that were prepared by impregnation method using iron (III nitrate as precursor and characterized by X-ray diffraction, infrared spectroscopy, nitrogen adsorption, pyridine adsorption, and hydrophilicity techniques. Catalysts 1Fe2O3/TS-1 showed maximum catalytic activity of hydroquinone product. In this research, the increase of hydroquinone formation rate is due to the higher hydrophilicity of Fe2O3/TS-1 catalysts compare to the parent catalyst, TS-1.   Keywords: Fe2O3/TS-1, hydrophilic site, phenol hydroxylation

  19. The relative age effect in the German Football TID Programme: biases in motor performance diagnostics and effects on single motor abilities and skills in groups of selected players.

    Science.gov (United States)

    Votteler, Andreas; Höner, Oliver

    2014-01-01

    This study examined the disturbing effects of relative age on the talent identification process in the talent development programme of the German Football Association. The bias in the selection rate was examined via the extent of relative age effects. The bias in motor performance diagnostics was analysed by comparing the motor performance of selected players with normal motor development. The mechanisms underlying the relative age biases in motor performance were examined by modelling the direct and indirect effects of relative age on single motor performance tests for sprint, running agility, dribbling and ball passing and control. Data from 10,130 selected football players from the U12 to U15 age groups were collected in autumn 2010. The birth distribution differed significantly from the reference population with approximately 61% of the players born in the first half of the year. The selection probability was approximately two times higher for players born in the first quarter of the year than for players born in the last quarter. Revised motor performance diagnostics showed better results on average for relatively younger players. Path analysis revealed significant direct and indirect relative age effects for physiologically demanding tests and almost no effects for technically demanding tests. Large sample sizes allowed high resolution in relative age with additional informational content and multivariate modelling of the complex relationships among relative age, physical development and motor performance. The results are discussed on how relative age affects the effectiveness and fairness of talent identification and development processes.

  20. Evaluation of a multiple-encounter in situ simulation for orientation of staff to a new paediatric emergency service: a single-group pretest/post-test study.

    Science.gov (United States)

    Davison, Michelle; Kinnear, Frances B; Fulbrook, Paul

    2017-10-01

    To assess the utility of a multiple-encounter in-situ (MEIS) simulation as an orientation tool for multidisciplinary staff prior to opening a new paediatric emergency service. A single-group pretest/post-test study was conducted. During the MEIS simulation, multidisciplinary staff with participant or observer roles managed eight children (mannequins) who attended triage with their parent/guardians (clinical facilitators) for a range of emergency presentations (structured scenarios designed to represent the expected range of presentations plus test various clinical pathways/systems). Participants were debriefed to explore clinical, systems and crisis-resource management issues. Participants also completed a pre-intervention and post-intervention questionnaire comprising statements about role confidence and orientation adequacy. Pre-test and post-test results were analysed using t-test and Wilcoxon signed rank test. Eighty-nine staff participated in the MEIS simulation, with the majority completing the pre-simulation and post-simulation questionnaire. There was a significant improvement in post-intervention versus pre-intervention Likert scores for role confidence and orientation adequacy (p=0.001 and orientation adequacy. Nearly all scenarios resulted in significant increases in participants' confidence levels. The MEIS simulation was of utility in orientation of staff, at least with respect to self-reported role confidence and orientation adequacy. Its effectiveness in practice or compared with other orientation techniques was not assessed, but it did identify several flaws in planned systems allowing remediation prior to opening.

  1. Discovery of iron group impurity ion spin states in single crystal Y{sub 2}SiO{sub 5} with strong coupling to whispering gallery photons

    Energy Technology Data Exchange (ETDEWEB)

    Goryachev, Maxim; Farr, Warrick G.; Carmo Carvalho, Natalia do; Creedon, Daniel L.; Le Floch, Jean-Michel [ARC Centre of Excellence for Engineered Quantum Systems, University of Western Australia, 35 Stirling Highway, Crawley WA 6009 (Australia); Probst, Sebastian [Physikalisches Institut, Karlsruhe Institute of Technology, D-76128 Karlsruhe (Germany); Bushev, Pavel [Experimentalphysik, Universität des Saarlandes, D-66123 Saarbrücken (Germany); Tobar, Michael E., E-mail: michael.tobar@uwa.edu.au [ARC Centre of Excellence for Engineered Quantum Systems, School of Physics, University of Western Australia, Crawley 6009 (Australia)

    2015-06-08

    Interaction of Whispering Gallery Modes (WGMs) with dilute spin ensembles in solids is an interesting paradigm of Hybrid Quantum Systems potentially beneficial for Quantum Signal Processing applications. Unexpected ion transitions are measured in single crystal Y{sub 2}SiO{sub 5} using WGM spectroscopy with large Zero Field Splittings at 14.7 GHz, 18.4 GHz, and 25.4 GHz, which also feature considerable anisotropy of the g-tensors as well as two inequivalent lattice sites, indicating spins from Iron Group Ion (IGI) impurities. The comparison of undoped and Rare-Earth doped crystals reveal that the IGIs are introduced during co-doping of Eu{sup 3+} or Er{sup 3+} with concentration at much lower levels of order 100 ppb. The strong coupling regime between an ensemble of IGI spins and WGM photons have been demonstrated at 18.4 GHz and near zero field. This approach together with useful optical properties of these ions opens avenues for “spins-in-solids” Quantum Electrodynamics.

  2. "The Effect of Hydroxyl Containing Tablet Excipients on the Adhesive Duration of Some Mucoadhesive Polymers "

    Directory of Open Access Journals (Sweden)

    Seyed Alireza Mortazavi

    2004-06-01

    Full Text Available In order to investigate the effect of hydroxyl group containing tablet excipients on the duration of adhesion of mucoadhesive polymers, discs containing Carbopol 934 (C934, polycarbophil (PC, sodium carboxymethyl cellulose, hydroxypropylmethyl cellulose (HPMC, tragacanth (trag. and sodium alginate (Na alg., either alone or in the presence of various amounts of excipients were prepared. The duration of adhesion of the prepared discs were determined in pH 7.0 phosphate buffer at 37°C. All the excipients examined reduced the duration of adhesion and the relative durability of the polymer containing discs. HPMC discs despite showing the longest duration of mucoadhesion, suffered the greatest reduction in adhesive properties in the presence of excipients which were examined. Following HPMC, Na alg. and then trag. discs showed the greatest sensitivity to the presence of excipients. The least reduction in the duration of adhesion was observed with PC and C934. Among the excipients tested, spray-dried lactose produced the greatest reduction in the duration of adhesion, followed by polyethylene glycol 6000 and pregelatinized starch. The smallest reduction in the adhesive properties of the test polymers was due to talc powder. Hence, it seems that addition of the tablet excipients adversely reduce the adhesive properties of mucoadhesive dosage forms, which should be carefully considered during their formulation.

  3. Biomineralization-Inspired Synthesis of Cerium-Doped Carbonaceous Nanoparticles for Highly Hydroxyl Radical Scavenging Activity

    Science.gov (United States)

    Zou, Shenqiang; Zhu, Xiaofang; Zhang, Lirong; Guo, Fan; Zhang, Miaomiao; Tan, Youwen; Gong, Aihua; Fang, Zhengzou; Ju, Huixiang; Wu, Chaoyang; Du, Fengyi

    2018-03-01

    Cerium oxide nanoparticles recently have received extensive attention in biomedical applications due to their excellent anti-oxidation performance. In this study, a simple, mild, and green approach was developed to synthesize cerium-doped carbonaceous nanoparticles (Ce-doped CNPs) using bio-mineralization of bull serum albumin (BSA) as precursor. The resultant Ce-doped CNPs exhibited uniform and ultrasmall morphology with an average size of 14.7 nm. XPS and FTIR results revealed the presence of hydrophilic group on the surface of Ce-doped CNPs, which resulted in excellent dispersity in water. The CCK-8 assay demonstrated that Ce-doped CNPs possessed favorable biocompatibility and negligible cytotoxicity. Using H2O2-induced reactive oxygen species (ROS) as model, Ce-doped CNPs showed highly hydroxyl radical scavenging capability. Furthermore, flow cytometry and live-dead staining results indicated that Ce-doped CNPs protected cells from H2O2-induced damage in a dose-dependent effect, which provided a direct evidence for anti-oxidative performance. These findings suggest that Ce-doped CNPs as novel ROS scavengers may provide a potential therapeutic prospect in treating diseases associated with oxidative stress.

  4. Detection analysis of surface hydroxyl active sites and simulation calculation of the surface dissociation constants of aqueous diatomite suspensions

    Science.gov (United States)

    Ma, Shu-Cui; Wang, Zhi-Gang; Zhang, Ji-Lin; Sun, De-Hui; Liu, Gui-Xia

    2015-02-01

    The surface properties of the diatomite were investigated using nitrogen adsorption/deadsorption isotherms, TG-DSC, FTIR, and XPS, and surface protonation-deprotonation behavior was determined by continuous acid-base potentiometric titration technique. The diatomite sample with porous honeycomb structure has a BET specific surface area of 10.21 m2/g and large numbers of surface hydroxyl functional groups (i.e. tbnd Si-OH, tbnd Fe-OH, and tbnd Al-OH). These surface hydroxyls can be protonated or deprotonated depending on the pH of the suspension. The experimental potentiometric data in two different ionic strength solutions (0.1 and 0.05 mol/L NaCl) were fitted using ProtoFit GUI V2.1 program by applying diffuse double layer model (DLM) with three amphoteric sites and minimizing the sum of squares between a dataset derivative function and a model derivative function. The optimized surface parameters (i.e. surface dissociation constants (log K1, log K2) and surface site concentrations (log C)) of the sample were obtained. Based on the optimized surface parameters, the surface species distribution was calculated using Program-free PHREEQC 3.1.2. Thus, this work reveals considerable new information about surface protonation-deprotonation processes and surface adsorptive behaviors of the diatomite, which helps us to effectively use the cheap and cheerful diatomite clay adsorbent.

  5. Restricted versus continued standard caloric intake during the management of refeeding syndrome in critically ill adults: a randomised, parallel-group, multicentre, single-blind controlled trial.

    Science.gov (United States)

    Doig, Gordon S; Simpson, Fiona; Heighes, Philippa T; Bellomo, Rinaldo; Chesher, Douglas; Caterson, Ian D; Reade, Michael C; Harrigan, Peter W J

    2015-12-01

    Equipoise exists regarding the benefits of restricting caloric intake during electrolyte replacement for refeeding syndrome, with half of intensive care specialists choosing to continue normal caloric intake. We aimed to assess whether energy restriction affects the duration of critical illness, and other measures of morbidity, compared with standard care. We did a randomised, multicentre, single-blind clinical trial in 13 hospital intensive care units (ICUs) in Australia (11 sites) and New Zealand (two sites). Adult critically ill patients who developed refeeding syndrome within 72 h of commencing nutritional support in the ICU were enrolled and allocated to receive continued standard nutritional support or protocolised caloric restriction. 1:1 computer-based randomisation was done in blocks of variable size, stratified by enrolment serum phosphate concentration (>0·32 mmol/L vs ≤0·32 mmol/L) and body-mass index (BMI; >18 kg/m(2)vs ≤18 kg/m(2)). The primary outcome was the number of days alive after ICU discharge, with 60 day follow-up, in a modified intention-to-treat population of all randomly allocated patients except those mistakenly enrolled. Days alive after ICU discharge was a composite outcome based on ICU length of stay, overall survival time, and mortality. The Refeeding Syndrome Trial was registered with the Australian and New Zealand Clinical Trials Registry (ANZCTR number 12609001043224). Between Dec 3, 2010, and Aug 13, 2014, we enrolled 339 adult critically ill patients: 170 were randomly allocated to continued standard nutritional support and 169 to protocolised caloric restriction. During the 60 day follow-up, the mean number of days alive after ICU discharge in 165 assessable patients in the standard care group was 39·9 (95% CI 36·4-43·7) compared with 44·8 (95% CI 40·9-49·1) in 166 assessable patients in the caloric restriction group (difference 4·9 days, 95% CI -2·3 to 13·6, p=0·19). Nevertheless, protocolised caloric

  6. Frequency Of C3435 Mdr1 And A6896g Cyp3a5 Single Nucleotide Polymorphism in an Iranian Population and Comparison with Other Ethnic Groups

    Directory of Open Access Journals (Sweden)

    N. AZARPIRA

    2006-11-01

    Full Text Available Background:It is well recognized that different patients respond in different ways to medications. The inter-individual variations are greater than the intera- individual variations,a finding consistent with the notion that inheritance is a determinant of drug responses. The recent identification of genetic polymorphisms in drug-metabolizing enzymes and drug transporters led to the hypothesis that genetic factors may be implicated in this interindividual variation. Single nucleotide polymorphism in common metabolic pathway,cytochrome P450 and common transporter,multidrug resistance-1 gene are two important sites that might involve clinically significant genetic variations. Ethnicity greatly influences these genetic polymorphism distributions. Methods: We studied the inheritance patterns of polymorphisms for MDR1 and CYP3A5 genes in the Iranian population and compared its genotype and allele frequencies with 3 different ethnic groups: Caucasian (United Kingdom, Chinese and Japanese. Results: We found striking differences in the distribution of MDR allelic variants between Iranian,Japanese and Chinese (p<0.02 and similar between the Iranian and Caucasian population.(p=0.06.Almost 50% of Iranian and Caucasian individuals were homozygous carriers of the variant T allele compared with 32% of the Japanese and 43% of the Chinese (p<0.02.More than half of Iranian subjects have at least one T allele,with lower P-gp level in small intestine.We also noted dramatic differences in the CYP3A5 alleles and genotypes distribution between Iranian subjects with other compared populations.99% of Iranian individuals were homozygous carriers of the variant G allele compared with about 70% of the Chinese and Japanese and 19% of the Caucasian population. The G/G genotype has a very low level of active cytochrome P450 enzyme.Conclusion:Our results emphasize the role of ethnicity in interindividual variability of the pharmacokinetic and pharmacodynamic characteristics

  7. The Efficacy and Tolerability of the Clonidine Transdermal Patch in the Treatment for Children with Tic Disorders: A Prospective, Open, Single-Group, Self-Controlled Study.

    Science.gov (United States)

    Song, Pan-Pan; Jiang, Li; Li, Xiu-Juan; Hong, Si-Qi; Li, Shuang-Zi; Hu, Yue

    2017-01-01

    To evaluate the efficacy and tolerability of a clonidine transdermal patch in the treatment of children with tic disorders (TD) and to establish a predictive model for patients. Forty-one patients who met the inclusion criteria entered into 12 weeks of prospective, open, single-group, self-controlled treatment with a clonidine transdermal patch. The Yale Global Tic Severity Scale (YGTSS) was employed before therapy (baseline) and at 4, 8, and 12 weeks after therapy. (1) The total effect rates of treatment with a clonidine transdermal patch were 29.27, 53.66, and 63.41% at 4, 8, and 12 weeks, respectively. Compared with the baseline, the differences were significant at three different observation periods. (2) Compared to the level of 25% reduction, there were significant decreases in the score-reducing rate of motor tic and total tic severities at 12 weeks. (3) If the disease course was ≤24 months and the motor tic score was tic score was >16, there was an effective rate of 57.1%. If the disease course was >24 months and the clinical classification was chronic TD, there was an effective rate of 62.5%. If the disease course was >24 months and the clinical classification was Tourette's syndrome, 90% of the patients were invalid. (4) The main adverse events were rash, slight dizziness, and headache. (1) When patients were pretreated with a D2-dopamine receptor antagonist that was ineffective or not tolerated well, switching to a clonidine transdermal patch treatment was effective and safe. (2) A clonidine transdermal patch could be a first-line medication for mild and moderate TD cases that are characterized by motor tics.

  8. Feasibility and Safety of a Powered Exoskeleton for Assisted Walking for Persons With Multiple Sclerosis: A Single-Group Preliminary Study.

    Science.gov (United States)

    Kozlowski, Allan J; Fabian, Michelle; Lad, Dipan; Delgado, Andrew D

    2017-07-01

    To examine the feasibility, safety, and secondary benefit potential of exoskeleton-assisted walking with one device for persons with multiple sclerosis (MS). Single-group longitudinal preliminary study with 8-week baseline, 8-week intervention, and 4-week follow-up. Outpatient MS clinic, tertiary care hospital. Participants (N=13; age range, 38-62y) were mostly women with Expanded Disability Status Scale scores ranging from 5.5 to 7.0. Exoskeleton-assisted walk training. Primary outcomes were accessibility (enrollment/screen pass), tolerability (completion/dropout), learnability (time to event for standing, walking, and sitting with little or no assistance), acceptability (satisfaction on the device subscale of the Quebec User Evaluation of Satisfaction with Assistive Technology version 2), and safety (event rates standardized to person-time exposure in the powered exoskeleton). Secondary outcomes were walking without the device (timed 25-foot walk test and 6-minute walk test distance), spasticity (Modified Ashworth Scale), and health-related quality of life (Patient-Reported Outcomes Measurement and Information System pain interference and Quality of Life in Neurological Conditions fatigue, sleep disturbance, depression, and positive affect and well-being). The device was accessible to 11 and tolerated by 5 participants. Learnability was moderate, with 5 to 15 sessions required to walk with minimal assistance. Safety was good; the highest adverse event rate was for skin issues at 151 per 1000 hours' exposure. Acceptability ranged from not very satisfied to very satisfied. Participants who walked routinely improved qualitatively on sitting, standing, or walking posture. Two participants improved and 2 worsened on ≥1 quality of life domain. The pattern of spasticity scores may indicate potential benefit. The device appeared feasible and safe for about a third of our sample, for whom routine exoskeleton-assisted walking may offer secondary benefits. Copyright

  9. The effect of a career activity on the students' perception of the nursing profession and their career plan: A single-group experimental study.

    Science.gov (United States)

    Yilmaz, Arzu Akman; Ilce, Arzu; Can Cicek, Saadet; Yuzden, Ganime Esra; Yigit, Ummuhan

    2016-04-01

    Students' conceptualizations of nursing and their reasons for choosing the profession motivate them and affect their education, work performance and career plans. Nursing educators should support them to plan their careers consciously during their education. The study aimed to investigate the effect of career-planning event for nursing students on their conceptualizations of the nursing profession and their career plans. The study was as single-group experimental study using a pre-test and post-test. The career-planning event was held in the conference hall of the university involved in the current study, and was open to the all students of the nursing school. The sample of the study consisted of 105 students who participated in the "Nursing Career Symposium" held on 27 March 2015. Methods At the event, the importance of career planning and the opportunities of the nursing profession was presented. The data were collected using a questionnaire consisted of two sections including descriptive characteristics and the opinions of the students regarding their career plans and Perception of Nursing Profession Scale. The students completed the first section of the questionnaire before the career event began and the second section of the questionnaire and scale both before and after the event. The participants had positive conceptualizations of the profession. Following a career event, the participants' opinions of professional qualities and professional status as measured through the Perception of Nursing Profession Scale showed a significant increase, and that the event had made an important contribution to their career plans. In the light of these results, it is possible to suggest that such events have an important place during education in that they introduce the nursing profession, and they develop the students' positive thoughts regarding the profession in terms of both course content and teaching methodology. Copyright © 2016 Elsevier Ltd. All rights reserved.

  10. Effect of rb-bFGF eye drops and hydroxyl indican eye drops on tear film stability and dry eye symptoms after age-related cataract surgery

    Directory of Open Access Journals (Sweden)

    Yu Ling

    2018-01-01

    Full Text Available AIM: To investigate the effect of recombinant bovine basic fibroblast growth factor(rb-bFGFeye drops and hydroxyl indican eye drops on tear film stability and dry eye symptoms after age-related cataract surgery. METHODS: Totally 80 patients with 80 affected eyes undergoing age-related cataract surgery in our hospital from January 2015 to October 2016 were selected as study subjects, and they were randomly divided into control group and experimental group with 40 patients(40 affected eyesin each group. The two groups were treated with hydroxyl indican eye drops and rb-bFGF eye drops, respectively. The clinical curative effect, inflammation related factors \\〖interleukin 6(IL-6, tumor necrosis factor α(TNF-α\\〗, Schirmer test(SⅠt, break-up time(BUTof tear film, corneal sodium fluorescein staining(FLand scores of dry eye symptoms in the two groups were observed. RESULTS: The total treatment effective rate of experimental group after treatment was significantly higher than that of the control group(90.0% vs 72.5%; χ2=4.021, PP>0.05. After treatment, IL-6, TNF-α, SⅠt, FL score and scores of dry eye symptoms in two groups significantly decreased while BUT significantly increased(PPCONCLUSION: In the treatment of patients after age-related cataract after surgery, rb-bFGF eye drops has more advantages over hydroxyl indican eye drops in regulating the expression of inflammatory factors, improving the tear film stability and relieving dry eye symptoms.

  11. Density functional theory based-study of 5-fluorouracil adsorption on β-cristobalite (1 1 1) hydroxylated surface: The importance of H-bonding interactions

    Energy Technology Data Exchange (ETDEWEB)

    Simonetti, S., E-mail: ssimonet@uns.edu.ar [Universidad Nacional del Sur (UNS)—Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Bahía Blanca (Argentina); Universidad Tecnológica Nacional (UTN), Bahía Blanca (Argentina); Compañy, A. Díaz [Comisión de Investigaciones Científicas (CIC), Buenos Aires (Argentina); Pronsato, E.; Juan, A.; Brizuela, G. [Universidad Nacional del Sur (UNS)—Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Bahía Blanca (Argentina); Lam, A. [Instituto de Ciencia y Tecnología de Materiales (IMRE), Universidad de La Habana (Cuba)

    2015-12-30

    Graphical abstract: - Highlights: • Favorable energies results in optimum four adsorption geometries. • Silanols are partially weakening and establish H-bonds with polar groups of 5-FU drug. • Dispersion forces approach the 5-FU molecule toward the surface. • Electron exchange is presented after adsorption. • H-bonds stabilize the molecule playing significant role in the adsorption mechanism. - Abstract: Silica-based mesoporous materials have been recently proposed as an efficient support for the controlled release of a popular anticancer drug, 5-fluorouracil (5-FU). Although the relevance of this topic, the atomistic details about the specific surface-drug interactions and the energy of adsorption are almost unknown. In this work, theoretical calculations using the Vienna Ab-initio Simulation Package (VASP) applying Grimme's—D2 correction were performed to elucidate the drug–silica interactions and the host properties that control 5-FU drug adsorption on β-cristobalite (1 1 1) hydroxylated surface. This study shows that hydrogen bonding, electron exchange, and dispersion forces are mainly involved to perform the 5-FU adsorption onto silica. This phenomenon, revealed by favorable energies, results in optimum four adsorption geometries that can be adopted for 5-FU on the hydroxylated silica surface. Silanols are weakening in response to the molecule approach and establish H-bonds with polar groups of 5-FU drug. The final geometry of 5-FU adopted on hydroxylated silica surface is the results of H-bonding interactions which stabilize and fix the molecule to the surface and dispersion forces which approach it toward silica (1 1 1) plane. The level of hydroxylation of the SiO{sub 2} (1 1 1) surface is reflected by the elevated number of hydrogen bonds that play a significant role in the adsorption mechanisms.

  12. Insight into the mechanism of methanol assistance with syngas conversion over partially hydroxylated γ-Al2O3(110D) surface in slurry bed.

    Science.gov (United States)

    Bai, Bing; Bai, Hui; Cao, Hao-Jie; Gao, Zhi-Hua; Zuo, Zhi-Jun; Huang, Wei

    2018-04-27

    Despite numerous studies devoted to the various properties of γ-Al2O3, the explorations of its catalytic activity remain scarce. In this study, density functional theory calculations are performed to study the elementary adsorption and reaction mechanisms for syngas conversion on partially hydroxylated γ-Al2O3(110D) surface in liquid paraffin. It is found that the partially hydroxylated γ-Al2O3(110D) surface with the hydroxyl coverage of 8.9 OH nm-2 is formed by two dissociative adsorptions of H2O on the dry γ-Al2O3(110D) surface. The hydroxyl coverage conditions play a key role in determining the dominant reaction mechanism on account of the existence of strong hydrogen bonds. The preferential pathway for syngas conversion with assistance of methanol over the partially hydroxylated γ-Al2O3(110D) surface in liquid paraffin has been proven to be CH3OH → CH3O + H → CH3 + OH, CH3 + CO → CH3CO. C2H5OH is then formed by successive hydrogenation via the pathway CH3CO + 3H → CH3CHO + 2H → CH3CH2O + H → C2H5OH. Here, CH3CHO formation by CH3CO hydrogenation is not inhibited. Actually, with the assistance of partially hydroxylated γ-Al2O3, CH3CHO has been synthesized with high selectivity in our previous experiment by the reaction of methanol and syngas, which provides favorable evidence for our results. The rate-limiting step is the formation of CH3O from CH3OH dehydrogenation with an activation barrier of 122.2 kJ mol-1. Moreover, the reaction barrier of CO insertion into the adsorbed CH3 group is at least 89.4 kJ mol-1, lower than those of CH4, C2H6, and CH3OCH3 formations. ADCH charge and ESP analyses indicate that the typical (Al, O) Lewis acid-base pair may have a significant effect upon the initial C-C chain formation. Thus, the present study provides a new approach for the rational tailoring and designing of new catalysts with superior reactivity involved in syngas conversion.

  13. Effects of Hydroxylation on PbS Quantum Dot Sensitized TiO2 Nanotube Array Photoelectrodes

    International Nuclear Information System (INIS)

    Liu, Zhongqing; Wang, Bin; Wu, Jianchun; Dong, Qiang; Zhang, Xiaoming; Xu, He

    2016-01-01

    ABSTRACT: The contact state at the heterojunction interfaces greatly influences the interfacial kinetics of the photoinduced charge carriers. In this study, we used a facile NaOH pretreatment to replenish the hydroxyl groups lost during the heat treatment for crystallization of TiO 2 nanotube arrays (TNAs) prepared via anodic oxidization. By reacting the carboxylic acid groups of thioglycolic acid (TGA) with the TiO 2 surface hydroxyl groups, TGA molecules were covalently linked to the TiO 2 surface and then PbS quantum dots (QDs) were anchored onto the TNAs via the successive ionic layer adsorption and reaction (SILAR) method. The sample microstructure and photoelectrochemical properties were analyzed with X-ray diffraction (XRD), transmission electron microscopy (TEM), field-emission scanning electron microscopy (FE-SEM),current–voltage characteristics (J–V), electrochemical impedance spectroscopy (EIS), transient photovoltage plots and Mott-Schottky curves. The contact state and electrostatic potential distribution between TiO 2 {1 0 1} and PbS {1 1 1} planes were estimated by using first principle simulation. It was found that the NaOH pretreatment could enhance the crystallization degree of PbS QDs, decrease the crystal face mismatch, dangling bond density and the interfacial resistance between PbS QDs and TiO 2 , and accelerate the interfacial separation and transfer of photoinduced charge carriers. The first principle calculations demonstrated that the PbS QDs and TiO 2 interfacial contact was strengthened, and the built-in electric field was induced from TiO 2 {1 0 1} towards PbS {1 1 1}. These combined effects apparently improved the device photoelectrochemical performance. Compared to the sample without pretreatment, the specimen pretreated with NaOH demonstrated 19.96% and 29.93% increases in peak photoconversion efficiency after five and ten cycles of SILAR deposition, respectively.

  14. Reactivity of hydropersulfides toward the hydroxyl radical unraveled: disulfide bond cleavage, hydrogen atom transfer, and proton-coupled electron transfer.

    Science.gov (United States)

    Anglada, Josep M; Crehuet, Ramon; Adhikari, Sarju; Francisco, Joseph S; Xia, Yu

    2018-02-14

    Hydropersulfides (RSSH) are highly reactive as nucleophiles and hydrogen atom transfer reagents. These chemical properties are believed to be key for them to act as antioxidants in cells. The reaction involving the radical species and the disulfide bond (S-S) in RSSH, a known redox-active group, however, has been scarcely studied, resulting in an incomplete understanding of the chemical nature of RSSH. We have performed a high-level theoretical investigation on the reactions of the hydroxyl radical (˙OH) toward a set of RSSH (R = -H, -CH 3 , -NH 2 , -C(O)OH, -CN, and -NO 2 ). The results show that S-S cleavage and H-atom abstraction are the two competing channels. The electron inductive effect of R induces selective ˙OH substitution at one sulfur atom upon S-S cleavage, forming RSOH and ˙SH for the electron donating groups (EDGs), whereas producing HSOH and ˙SR for the electron withdrawing groups (EWGs). The H-Atom abstraction by ˙OH follows a classical hydrogen atom transfer (hat) mechanism, producing RSS˙ and H 2 O. Surprisingly, a proton-coupled electron transfer (pcet) process also occurs for R being an EDG. Although for RSSH having EWGs hat is the leading channel, S-S cleavage can be competitive or even dominant for the EDGs. The overall reactivity of RSSH toward ˙OH attack is greatly enhanced with the presence of an EDG, with CH 3 SSH being the most reactive species found in this study (overall rate constant: 4.55 × 10 12 M -1 s -1 ). Our results highlight the complexity in RSSH reaction chemistry, the extent of which is closely modulated by the inductive effect of the substituents in the case of the oxidation by hydroxyl radicals.

  15. Selective 2′-hydroxyl acylation analyzed by primer extension and mutational profiling (SHAPE-MaP) for direct, versatile, and accurate RNA structure analysis

    Science.gov (United States)

    Smola, Matthew J.; Rice, Greggory M.; Busan, Steven; Siegfried, Nathan A.; Weeks, Kevin M.

    2016-01-01

    SHAPE chemistries exploit small electrophilic reagents that react with the 2′-hydroxyl group to interrogate RNA structure at single-nucleotide resolution. Mutational profiling (MaP) identifies modified residues based on the ability of reverse transcriptase to misread a SHAPE-modified nucleotide and then counting the resulting mutations by massively parallel sequencing. The SHAPE-MaP approach measures the structure of large and transcriptome-wide systems as accurately as for simple model RNAs. This protocol describes the experimental steps, implemented over three days, required to perform SHAPE probing and construct multiplexed SHAPE-MaP libraries suitable for deep sequencing. These steps include RNA folding and SHAPE structure probing, mutational profiling by reverse transcription, library construction, and sequencing. Automated processing of MaP sequencing data is accomplished using two software packages. ShapeMapper converts raw sequencing files into mutational profiles, creates SHAPE reactivity plots, and provides useful troubleshooting information, often within an hour. SuperFold uses these data to model RNA secondary structures, identify regions with well-defined structures, and visualize probable and alternative helices, often in under a day. We illustrate these algorithms with the E. coli thiamine pyrophosphate riboswitch, E. coli 16S rRNA, and HIV-1 genomic RNAs. SHAPE-MaP can be used to make nucleotide-resolution biophysical measurements of individual RNA motifs, rare components of complex RNA ensembles, and entire transcriptomes. The straightforward MaP strategy greatly expands the number, length, and complexity of analyzable RNA structures. PMID:26426499

  16. Certolizumab Pegol for Treating Rheumatoid Arthritis Following Inadequate Response to a TNF-α Inhibitor: An Evidence Review Group Perspective of a NICE Single Technology Appraisal.

    Science.gov (United States)

    Bermejo, Iñigo; Stevenson, Matt; Archer, Rachel; Stevens, John W; Goka, Edward; Clowes, Mark; Scott, David L; Young, Adam

    2017-11-01

    As part of its single technology appraisal (STA) process, the National Institute for Health and Care Excellence (NICE) invited the manufacturer (UCB Pharma) of certolizumab pegol (CZP; Cimzia ® ) to submit evidence of its clinical and cost effectiveness for the treatment of rheumatoid arthritis (RA) following inadequate response to a tumour necrosis factor-α inhibitor (TNFi). The School of Health and Related Research Technology Appraisal Group at the University of Sheffield was commissioned to act as the independent Evidence Review Group (ERG). The ERG produced a detailed review of the evidence for the clinical and cost effectiveness of the technology, based upon the company's submission to NICE. The clinical effectiveness evidence in the company's submission for CZP was based predominantly on six randomised controlled trials (RCTs) comparing the efficacy of CZP against placebo. The clinical effectiveness review identified no head-to-head evidence on the efficacy of CZP against the comparators within the scope; therefore, the company performed a network meta-analysis (NMA). The company's NMA concluded that CZP had a similar efficacy to that of its comparators. The company submitted a Markov model that assessed the incremental cost effectiveness of CZP versus comparator biologic disease-modifying antirheumatic drugs (bDMARDs) for the treatment of RA from the perspective of the National Health Service for three decision problems, each of which followed an inadequate response to a TNFi. These were (1) a comparison against rituximab (RTX) in combination with methotrexate (MTX); (2) a comparison against bDMARDs when RTX was contraindicated or withdrawn due to an adverse event; and (3) a comparison against bDMARDs when MTX was contraindicated or withdrawn due to an adverse event. Results from the company's economic evaluation showed that CZP resulted in a similar number of quality-adjusted life years (QALYs) produced at similar or lower costs compared with comparator b

  17. Rivaroxaban for Preventing Atherothrombotic Events in People with Acute Coronary Syndrome and Elevated Cardiac Biomarkers: An Evidence Review Group Perspective of a NICE Single Technology Appraisal.

    Science.gov (United States)

    Pandor, Abdullah; Pollard, Daniel; Chico, Tim; Henderson, Robert; Stevenson, Matt

    2016-05-01

    As part of its Single Technology Appraisal process, the National Institute for Health and Care Excellence (NICE) invited the company that manufactures rivaroxaban (Xarelto, Bayer) to submit evidence of the clinical and cost effectiveness of rivaroxaban for the prevention of adverse outcomes in patients after the acute management of acute coronary syndrome (ACS). The School of Health and Related Research Technology Appraisal Group at the University of Sheffield was commissioned to act as the independent Evidence Review Group (ERG). The ERG produced a critical review of the evidence for the clinical and cost effectiveness of the technology, based upon the company's submission to NICE. The evidence was derived mainly from a randomised, double-blind, phase III, placebo-controlled trial of rivaroxaban (either 2.5 or 5 mg twice daily) in patients with recent ACS [unstable angina, non-ST segment elevation myocardial infarction (NSTEMI) or ST segment elevation myocardial infarction (STEMI)]. In addition, all patients received antiplatelet therapy [aspirin alone or aspirin and a thienopyridine either as clopidogrel (approximately 99 %) or ticlopidine (approximately 1 %) according to national or local guidelines]. The higher dose of rivaroxaban (5 mg twice daily) did not form part of the marketing authorisation. A post hoc subgroup analysis of the licensed patients who had ACS with elevated cardiac biomarkers (that is, patients with STEMI and NSTEMI) without prior stroke or transient ischaemic stroke showed that compared with standard care, the addition of rivaroxaban (2.5 mg twice daily) to existing antiplatelet therapy reduced the composite endpoint of cardiovascular mortality, myocardial infarction or stroke, but increased the risk of major bleeding and intracranial haemorrhage. However, there were a number of limitations in the evidence base that warrant caution in its interpretation. In particular, the evidence may be confounded because of the post hoc subgroup

  18. Crizotinib for Untreated Anaplastic Lymphoma Kinase-Positive Non-Small-Cell Lung Cancer: An Evidence Review Group Perspective of a NICE Single Technology Appraisal.

    Science.gov (United States)

    Morgan, Philip; Woolacott, Nerys; Biswas, Mousumi; Mebrahtu, Teumzghi; Harden, Melissa; Hodgson, Robert

    2017-09-01

    As part of the National Institute for Health and Care Excellence (NICE) single technology appraisal process, the manufacturer of crizotinib submitted evidence on the clinical and cost effectiveness of crizotinib in untreated anaplastic lymphoma kinase-positive (ALK-positive) non-small-cell lung cancer (NSCLC). Crizotinib has previously been assessed by NICE for patients with previously treated ALK-positive NSCLC (TA 296). It was not approved in this previous appraisal, but had been made available through the cancer drugs fund. As part of this new appraisal, the company included a price discount patient access scheme (PAS). The Centre for Reviews and Dissemination and Centre for Health Economics Technology Appraisal Group at the University of York was commissioned to act as the independent Evidence Review Group (ERG). This article provides a description of the company's submission and the ERG's review and summarises the resulting NICE guidance issued in August 2016. The main clinical-effectiveness data were derived from a multicentre randomised controlled trial-PROFILE 1014-that compared crizotinib with pemetrexed chemotherapy in combination with carboplatin or cisplatin in patients with untreated non-squamous ALK-positive NSCLC. In the trial, crizotinib demonstrated improvements in progression-free survival (PFS) and overall survival (OS). The company's economic model was a three-state 'area under the curve' Markov model. The base-case incremental cost-effectiveness ratio (ICER) was estimated to be greater than £50,000 per quality-adjusted life-year (QALY) gained (excluding the PAS discount). The ERG assessment of the evidence submitted by the company raised a number of concerns. In terms of the clinical evidence, the OS benefit was highly uncertain due to the cross-over permitted in the trial and the immaturity of the data; only 26% of events had occurred by the data cut-off point. In the economic modelling, the most significant concerns related to the analysis

  19. Hydroxylative activity of Aspergillus niger towards androst-4-ene and androst-5-ene steroids.

    Science.gov (United States)

    Świzdor, Alina; Panek, Anna; Milecka-Tronina, Natalia

    2017-10-01

    Aspergillus niger, one of fungal species most frequently used for experimental and industrial-scale biotransformations of various organic compounds, is generally known to transform steroids at 16β position. In this work, application of the strain A. niger KCH910 to bioconversion of dehydroepiandrosterone (DHEA), androstenediol and testosterone is described, with emphasis on the metabolic steps leading to the products. Evidence from this study indicated that incubated 5-ene steroids underwent bioconversion within two metabolic pathways: oxidation by the action of 3β-HSD (3β-hydroxysteroid dehydrogenase) to 4-ene steroids, and minor allylic hydroxylation to epimeric 7-alcohols. Further transformation of the 3-oxo-4-ene metabolites resulted in non-selective 16-hydroxylation. It is the first report on an A. niger strain able to introduce not only 16β- but also 16α-hydroxyl function into steroids. Copyright © 2017. Published by Elsevier Inc.

  20. Cabazitaxel for Hormone-Relapsed Metastatic Prostate Cancer Previously Treated With a Docetaxel-Containing Regimen: An Evidence Review Group Perspective of a NICE Single Technology Appraisal.

    Science.gov (United States)

    Kearns, Benjamin; Pandor, Abdullah; Stevenson, Matt; Hamilton, Jean; Chambers, Duncan; Clowes, Mark; Graham, John; Kumar, M Satish

    2017-04-01

    As part of its single technology appraisal (STA) process, the National Institute for Health and Care Excellence (NICE) invited the company that manufactures cabazitaxel (Jevtana ® , Sanofi, UK) to submit evidence for the clinical and cost effectiveness of cabazitaxel for treatment of patients with metastatic hormone-relapsed prostate cancer (mHRPC) previously treated with a docetaxel-containing regimen. The School of Health and Related Research Technology Appraisal Group at the University of Sheffield was commissioned to act as the independent Evidence Review Group (ERG). The ERG produced a critical review of the evidence for the clinical and cost effectiveness of the technology based upon the company's submission to NICE. Clinical evidence for cabazitaxel was derived from a multinational randomised open-label phase III trial (TROPIC) of cabazitaxel plus prednisone or prednisolone compared with mitoxantrone plus prednisone or prednisolone, which was assumed to represent best supportive care. The NICE final scope identified a further three comparators: abiraterone in combination with prednisone or prednisolone; enzalutamide; and radium-223 dichloride for the subgroup of people with bone metastasis only (no visceral metastasis). The company did not consider radium-223 dichloride to be a relevant comparator. Neither abiraterone nor enzalutamide has been directly compared in a trial with cabazitaxel. Instead, clinical evidence was synthesised within a network meta-analysis (NMA). Results from TROPIC showed that cabazitaxel was associated with a statistically significant improvement in both overall survival and progression-free survival compared with mitoxantrone. Results from a random-effects NMA, as conducted by the company and updated by the ERG, indicated that there was no statistically significant difference between the three active treatments for both overall survival and progression-free survival. Utility data were not collected as part of the TROPIC trial, and

  1. SU-F-T-676: Measurement of Hydroxyl Radicals in Radiolized Water Systems

    Energy Technology Data Exchange (ETDEWEB)

    Ouyang, Z; Ngwa, W [University of Massachusetts Lowell, Lowell, MA (United States); Brigham and Women’s Hospital, Dana-Farber Cancer Institute and Harvard Medical School, Boston, MA (United States); Strack, G; Sajo, E [University of Massachusetts Lowell, Lowell, MA (United States)

    2016-06-15

    Purpose: Hydroxyl radicals can be produced within tissue by radiation therapy, and they are largely responsible for DNA damage and cell killing. Coumarin-3-carboxylic acid (3-CCA) and crystal violet are reported to react with hydroxyl radicals and can be used for fluorescence and absorbance measurements, respectively. This study assesses the ability of hydroxyl measurement for both 3-CCA and crystal violet in radiolized water systems in order to provide dosimetric information in radiation chemistry and radiation biology experiments. Methods: 3-CCA and crystal violet were both dissolved in phosphate buffered saline (PBS, pH 7.4) with final concentrations 0.5 mg/mL and 0.05 mg/mL. 3-CCA and control solutions (PBS only) were loaded in black bottom 96-well plates. Crystal violet and control solutions were loaded in clear bottom 96-well plates. The prepared solutions were irradiated at 2 Gy using a small animal radiation research platform. Fluorescence reading with 360 nm excitation wavelength and 485 nm emission wavelength was done for 3-CCA, and absorbance reading at wavelength 580 nm was done for crystal violet before and after radiation. Results: 3-CCA showed clear difference in fluorescence before and after radiation, which suggested hydroxyl production during radiation. However, crystal violet absorbance at 580 nm was not changed significantly by radiation. Conclusion: The overall conclusion is that 3-CCA can be used for hydroxyl measurement in radiolized water systems, while crystal violet cannot, although crystal violet is reported widely to react with hydroxyl radicals produced in Fenton reactions. Possible reasons could relate to reaction pH.

  2. Comprehensive database of Manufactured Gas Plant tars. Part C. Heterocyclic and hydroxylated polycyclic aromatic hydrocarbons.

    Science.gov (United States)

    Gallacher, Christopher; Thomas, Russell; Lord, Richard; Kalin, Robert M; Taylor, Chris

    2017-08-15

    Coal tars are a mixture of organic and inorganic compounds that were by-products from the manufactured gas and coke making industries. The tar compositions varied depending on many factors such as the temperature of production and the type of retort used. For this reason a comprehensive database of the compounds found in different tar types is of value to understand both how their compositions differ and what potential chemical hazards are present. This study focuses on the heterocyclic and hydroxylated compounds present in a database produced from 16 different tars from five different production processes. Samples of coal tar were extracted using accelerated solvent extraction (ASE) and derivatized post-extraction using N,O-bis(trimethylsilyl)trifluoroacetamide (BSTFA) with 1% trimethylchlorosilane (TMCS). The derivatized samples were analysed using two-dimensional gas chromatography combined with time-of-flight mass spectrometry (GCxGC/TOFMS). A total of 865 heterocyclic compounds and 359 hydroxylated polycyclic aromatic hydrocarbons (PAHs) were detected in 16 tar samples produced by five different processes. The contents of both heterocyclic and hydroxylated PAHs varied greatly with the production process used, with the heterocyclic compounds giving information about the feedstock used. Of the 359 hydroxylated PAHs detected the majority would not have been be detected without the use of derivatization. Coal tars produced using different production processes and feedstocks yielded tars with significantly different heterocyclic and hydroxylated contents. The concentrations of the individual heterocyclic compounds varied greatly even within the different production processes and provided information about the feedstock used to produce the tars. The hydroxylated PAH content of the samples provided important analytical information that would otherwise not have been obtained without the use of derivatization and GCxGC/TOFMS. Copyright © 2017 John Wiley & Sons, Ltd.

  3. V color centers in electrolytically colored hydroxyl-doped sodium chloride crystals

    International Nuclear Information System (INIS)

    Gu Hongen; Song Cuiying; Han Li

    2006-01-01

    Hydroxyl-doped sodium chloride crystals were successfully colored electrolytically by using pointed anode and flat cathode at various temperatures and under various electric field strengths. V 2 and V 3 color centers were produced in the colored crystals. Current-time curves for the electrolytic colorations were given, and activation energy for the V 2 and V 3 color center migration was determined. Production of the V 2 and V 3 color centers and formation of current zones for the electrolytic colorations of the hydroxyl-doped sodium chloride crystals are explained

  4. Regioselective alkane hydroxylation with a mutant CYP153A6 enzyme

    Science.gov (United States)

    Koch, Daniel J.; Arnold, Frances H.

    2013-01-29

    Cytochrome P450 CYP153A6 from Myobacterium sp. strain HXN1500 was engineered using in-vivo directed evolution to hydroxylate small-chain alkanes regioselectively. Mutant CYP153A6-BMO1 selectively hydroxylates butane and pentane at the terminal carbon to form 1-butanol and 1-pentanol, respectively, at rates greater than wild-type CYP153A6 enzymes. This biocatalyst is highly active for small-chain alkane substrates and the regioselectivity is retained in whole-cell biotransformations.

  5. Effect of Hydroxyl Concentration on Chemical Sensitivity of Polyvinyl Alcohol/Carbon-Black Composite Chemiresistors

    International Nuclear Information System (INIS)

    Hughes, Robert C.; Patel, Sanjay V.; Yelton, W. Graham

    1999-01-01

    The sensitivity and selectivity of polyvinyl alcohol (PVA) / carbon black composite films have been found to vary depending upon the hydroxylation percentage (''-OH'') of the polymer. These chemiresistors made from PVA films whose polymer backbone is 88% hydroxylated (PVA88) have a high sensitivity to water, while chemiresistors made from PVA75 have a higher sensitivity to methanol. The minor differences in polymer composition result in films with different Hildebrand volubility parameters. The relative responses of several different PVA-based chemiresistors to solvents with different volubility parameters are presented. In addition, polyvinyl acetate (PVAC) films with PVA88 are used in an array to distinguish the responses to methanol-water mixtures

  6. Activity of Oligoresveratrols from Stem Bark of Hopea mengarawan (Dipterocarpaceae as Hydroxyl Radical Scavenger

    Directory of Open Access Journals (Sweden)

    SRI ATUN

    2006-06-01

    Full Text Available Four oligoresveratrols ranging from dimer to tetramer, isolated from stem bark of Hopea mengarawan (Dipterocarpaceae plants were tested for their activity as hydroxyl radical scavenger. The activity of these compounds was evaluated against the 2-deoxyribose degradation induced by the hydroxyl radical generated via a Fenton-type reaction. Result showed that balanocarpol, heimiol A, vaticanol G, and vaticanol B had IC50 3.83; 15.44; 2.01; and 4.71 µM, respectively. These results suggest that oligoresveratrols from stem bark of H. mengarawan maybe useful as potential sources of natural antioxidants.

  7. Hydroxylation of the Herbicide Isoproturon by Fungi Isolated from Agricultural soil

    DEFF Research Database (Denmark)

    Rønhede, S.; Jensen, Bo; Rosendahl, Søren

    2005-01-01

    Several asco-, basidio-, and zygomycetes isolated from an agricultural field were shown to be able to hydroxylate the phenylurea herbicide isoproturon [N-(4-isopropylphenyl)-N',N'-dimethylurea] to N-(4-(2-hydroxy-1-methylethyl)phenyl)-N',N'-dimethylurea and N-(4-(1-hydroxy-1-methylethyl)phenyl)-N......Several asco-, basidio-, and zygomycetes isolated from an agricultural field were shown to be able to hydroxylate the phenylurea herbicide isoproturon [N-(4-isopropylphenyl)-N',N'-dimethylurea] to N-(4-(2-hydroxy-1-methylethyl)phenyl)-N',N'-dimethylurea and N-(4-(1-hydroxy-1-methylethyl...

  8. Diatomite as high performance and environmental friendly catalysts for phenol hydroxylation with H2O2

    Directory of Open Access Journals (Sweden)

    Yuxin Jia et al

    2007-01-01

    Full Text Available A series of diatomite catalysts were treated and characterized. For the first time, the resulting materials were used in catalysis for the hydroxylation of phenol with H2O2 and showed very high hydroxylation activity due to the Fe species in the diatomite. The effect of HCl treatment, contents of catalysts and H2O2 were investigated and the active components of diatomite were discussed. The results show that diatomite is the promising candidate for industrial output due to their high catalytic activity, easy physical separation and very low costs.

  9. A novel dihydropyridine with 3-aryl meta-hydroxyl substitution blocks L-type calcium channels in rat cardiomyocytes

    International Nuclear Information System (INIS)

    Galvis-Pareja, David; Zapata-Torres, Gerald; Hidalgo, Jorge; Ayala, Pedro

    2014-01-01

    Rationale: Dihydropyridines are widely used for the treatment of several cardiac diseases due to their blocking activity on L-type Ca 2+ channels and their renowned antioxidant properties. Methods: We synthesized six novel dihydropyridine molecules and performed docking studies on the binding site of the L-type Ca 2+ channel. We used biochemical techniques on isolated adult rat cardiomyocytes to assess the efficacy of these molecules on their Ca 2+ channel-blocking activity and antioxidant properties. The Ca 2+ channel-blocking activity was evaluated by confocal microscopy on fluo-3AM loaded cardiomyocytes, as well as using patch clamp experiments. Antioxidant properties were evaluated by flow cytometry using the ROS sensitive dye 1,2,3 DHR. Results: Our docking studies show that a novel compound with 3-OH substitution inserts into the active binding site of the L-type Ca 2+ channel previously described for nitrendipine. In biochemical assays, the novel meta-OH group in the aryl in C4 showed a high blocking effect on L-type Ca 2+ channel as opposed to para-substituted compounds. In the tests we performed, none of the molecules showed antioxidant properties. Conclusions: Only substitutions in C2, C3 and C5 of the aryl ring render dihydropyridine compounds with the capacity of blocking LTCC. Based on our docking studies, we postulate that the antioxidant activity requires a larger group than the meta-OH substitution in C2, C3 or C5 of the dihydropyridine ring. - Highlights: • Dihydropyridine (DHP) molecules are widely used in cardiovascular disease. • DHPs block Ca 2+ entry through LTCC—some DHPs have antioxidant activity as well. • We synthesized 6 new DHPs and tested their Ca 2+ blocking and antioxidant activities. • 3-Aryl meta-hydroxyl substitution strongly increases their Ca 2+ blocking activity. • 3-Aryl meta-hydroxyl substitution did not affect the antioxidant properties

  10. Oxidative damage to fibronectin. 2. The effect of H2O2 and the hydroxyl radical

    International Nuclear Information System (INIS)

    Vissers, M.C.; Winterbourn, C.C.

    1991-01-01

    The effect of H2O2 and the hydroxyl radical (.OH) on fibronectin was investigated. .OH was generated in three ways: (1) by radiolysis with 60Co under N2O, or by the Fenton system using either (2) equimolar Fe(2+)-EDTA and H2O2 or (3) H2O2 and catalytic amounts of Fe(2+)-EDTA recycled with ascorbate. Each system had a different effect. H2O2 alone caused no changes, even at an 800-fold molar excess. Radiolytic .OH caused a rapid loss of tryptophan fluorescence, an increase in bityrosine fluorescence, and extensive crosslinking. The Fenton system using Fe-EDTA, H2O2, and ascorbate caused a loss in tryptophan fluorescence, a smaller increase in bityrosine than was seen with radiolytic .OH, and a threefold increase in carbonyl groups. On sodium dodecyl sulfate-polyacrylamide gel electrophoresis fragmentation of fibronectin was seen. In contrast, when .OH was generated with equimolar Fe-EDTA and H2O2, the only change was a small increase in bityrosine fluorescence at the highest dose of oxidant. None of the systems used affected cysteine. All the changes except the loss of tryptophan by radiolytic .OH were completely inhibited with mannitol. The differences seen with radiolytic .OH and the Fe-EDTA, H2O2, ascorbate system were not solely due to O2 in the latter system since similar results were obtained under N2. The differences between radiolytic .OH and the Fenton systems could be partly due to the components of the latter systems reacting with .OH and thus competing with fibronectin. The authors results demonstrate that the extent and type of fibronectin damage by .OH is dependent on the mode of radical generation

  11. Reaction mechanism of sterol hydroxylation by steroid C25 dehydrogenase - Homology model, reactivity and isoenzymatic diversity.

    Science.gov (United States)

    Rugor, Agnieszka; Wójcik-Augustyn, Anna; Niedzialkowska, Ewa; Mordalski, Stefan; Staroń, Jakub; Bojarski, Andrzej; Szaleniec, Maciej

    2017-08-01

    Steroid C25 dehydrogenase (S25DH) is a molybdenum-containing oxidoreductase isolated from the anaerobic Sterolibacterium denitrificans Chol-1S. S25DH is classified as 'EBDH-like' enzyme (EBDH, ethylbenzene dehydrogenase) and catalyzes the introduction of an OH group to the C25 atom of a sterol aliphatic side-chain. Due to its regioselectivity, S25DH is proposed as a catalyst in production of pharmaceuticals: calcifediol or 25-hydroxycholesterol. The aim of presented research was to obtain structural model of catalytic subunit α and investigate the reaction mechanism of the O 2 -independent tertiary carbon atom activation. Based on homology modeling and theoretical calculations, a S25DH α subunit model was for the first time characterized and compared to other S25DH-like isoforms. The molecular dynamics simulations of the enzyme-substrate complexes revealed two stable binding modes of a substrate, which are stabilized predominantly by van der Waals forces in the hydrophobic substrate channel. However, H-bond interactions involving polar residues with C3=O/C3-OH in the steroid ring appear to be responsible for positioning the substrate. These results may explain the experimental kinetic results which showed that 3-ketosterols are hydroxylated 5-10-fold faster than 3-hydroxysterols. The reaction mechanism was studied using QM:MM and QM-only cluster models. The postulated mechanism involves homolytic CH cleavage by the MoO ligand, giving rise to a radical intermediate with product obtained in an OH rebound process. The hypothesis was supported by kinetic isotopic effect (KIE) experiments involving 25,26,26,26-[ 2 H]-cholesterol (4.5) and the theoretically predicted intrinsic KIE (7.0-7.2). Finally, we have demonstrated that the recombinant S25DH-like isoform catalyzes the same reaction as S25DH. Copyright © 2017 Elsevier Inc. All rights reserved.

  12. NDUFAF5 Hydroxylates NDUFS7 at an Early Stage in the Assembly of Human Complex I*

    Science.gov (United States)

    Rhein, Virginie F.; Carroll, Joe; Ding, Shujing; Fearnley, Ian M.; Walker, John E.

    2016-01-01

    Complex I (NADH ubiquinone oxidoreductase) in mammalian mitochondria is an L-shaped assembly of 45 proteins. One arm lies in the inner membrane, and the other extends about 100 Å into the matrix of the organelle. The extrinsic arm contains binding sites for NADH, the primary electron acceptor FMN, and seven iron-sulfur clusters that form a pathway for electrons linking FMN to the terminal electron acceptor, ubiquinone, which is bound in a tunnel in the region of the junction between the arms. The membrane arm contains four antiporter-like domains, energetically coupled to the quinone site and involved in pumping protons from the matrix into the intermembrane space contributing to the proton motive force. Seven of the subunits, forming the core of the membrane arm, are translated from mitochondrial genes, and the remaining subunits, the products of nuclear genes, are imported from the cytosol. Their assembly is coordinated by at least thirteen extrinsic assembly factor proteins that are not part of the fully assembled complex. They assist in insertion of co-factors and in building up the complex from smaller sub-assemblies. One such factor, NDUFAF5, belongs to the family of seven-β-strand S-adenosylmethionine-dependent methyltransferases. However, similar to another family member, RdmB, it catalyzes the introduction of a hydroxyl group, in the case of NDUFAF5, into Arg-73 in the NDUFS7 subunit of human complex I. This modification occurs early in the pathway of assembly of complex I, before the formation of the juncture between peripheral and membrane arms. PMID:27226634

  13. NDUFAF5 Hydroxylates NDUFS7 at an Early Stage in the Assembly of Human Complex I.

    Science.gov (United States)

    Rhein, Virginie F; Carroll, Joe; Ding, Shujing; Fearnley, Ian M; Walker, John E

    2016-07-08

    Complex I (NADH ubiquinone oxidoreductase) in mammalian mitochondria is an L-shaped assembly of 45 proteins. One arm lies in the inner membrane, and the other extends about 100 Å into the matrix of the organelle. The extrinsic arm contains binding sites for NADH, the primary electron acceptor FMN, and seven iron-sulfur clusters that form a pathway for electrons linking FMN to the terminal electron acceptor, ubiquinone, which is bound in a tunnel in the region of the junction between the arms. The membrane arm contains four antiporter-like domains, energetically coupled to the quinone site and involved in pumping protons from the matrix into the intermembrane space contributing to the proton motive force. Seven of the subunits, forming the core of the membrane arm, are translated from mitochondrial genes, and the remaining subunits, the products of nuclear genes, are imported from the cytosol. Their assembly is coordinated by at least thirteen extrinsic assembly factor proteins that are not part of the fully assembled complex. They assist in insertion of co-factors and in building up the complex from smaller sub-assemblies. One such factor, NDUFAF5, belongs to the family of seven-β-strand S-adenosylmethionine-dependent methyltransferases. However, similar to another family member, RdmB, it catalyzes the introduction of a hydroxyl group, in the case of NDUFAF5, into Arg-73 in the NDUFS7 subunit of human complex I. This modification occurs early in the pathway of assembly of complex I, before the formation of the juncture between peripheral and membrane arms. © 2016 by The American Society for Biochemistry and Molecular Biology, Inc.

  14. Emergency transfusion of patients with unknown blood type with blood group O Rhesus D positive red blood cell concentrates: a prospective, single-centre, observational study.

    Science.gov (United States)

    Selleng, Kathleen; Jenichen, Gregor; Denker, Kathrin; Selleng, Sixten; Müllejans, Bernd; Greinacher, Andreas

    2017-05-01

    Emergency patients with unknown blood type usually receive O Rhesus D negative (RhD-) red blood cell concentrates until their blood group is determined to prevent RhD+ related adverse transfusion reactions. As 85% of individuals are RhD+, this consumption of O RhD- red blood cell concentrates contributes to shortages of O RhD- red blood cell concentrates, sometimes forcing transfusion of known RhD- patients with RhD+ red blood cell concentrates. Here we report the outcome of this transfusion policy transfusing all emergency patients with unknown blood type with O RhD+ red blood cell concentrates. In this prospective single-centre observational study done between Jan 1, 2001, and Dec 31, 2015, we assessed all consecutive RhD- patients at the University Medicine Greifswald who received RhD+ red blood cell concentrates (emergency patients with unknown blood type; and RhD- patients receiving RhD+ red blood cell concentrates during RhD- red blood cell concentrate shortages). No patients were excluded. The primary endpoint was anti-D allo-immunisation at 2 months follow-up or later. Patients were followed up and tested for immunisation against red blood cell antigens using the direct antiglobulin test and an antibody screen every 3-5 days for 4 weeks or until death, or hospital discharge. Surviving patients were screened for development of anti-D antibodies for up to 12 months (at the predefined timepoints 2, 3, 6, and 12 months) after RhD+ red blood cell transfusion. 437 emergency patients, of whom 85 (20%) were RhD-, received 2836 RhD+ red blood cell concentrates. The overall risk of inducing anti-D antibodies (in all 437 recipients) was 17 (4%, 95% CI 2·44-6·14) of 437 (assuming all patients lost to follow-up developed anti-D allo-immunisation). During this period, 110 known RhD- patients received RhD+ red blood cell concentrates during RhD- red blood cell concentrate shortages. Of these, 29 (26%; 95% CI 19·0-35·3) developed anti-D allo-immunisation (assuming all

  15. Pharmacokinetic comparison of acetaminophen elixir versus suppositories in vaccinated infants (aged 3 to 36 months): a single-dose, open-label, randomized, parallel-group design.

    Science.gov (United States)

    Walson, Philip D; Halvorsen, Mark; Edge, James; Casavant, Marcel J; Kelley, Michael T

    2013-02-01

    Because of practical problems and ethical concerns, few studies of the pharmacokinetics (PK) of acetaminophen (ACET) in infants have been published. The goal of this study was to compare the PK of an ACET rectal suppository with a commercially available ACET elixir to complete a regulatory obligation to market the suppository. This study was not submitted previously because of numerous obstacles related to both the investigators and the commercial entities associated with the tested product. Thirty infants (age 3-36 months) prescribed ACET for either fever, pain, or postimmunization prophylaxis of fever and discomfort were randomized to receive a single 10- to 15-mg/kg ACET dose either as the rectal suppository or oral elixir. Blood was collected at selected times for up to 8 hours after administration. ACET concentrations were measured by using a validated HPLC method, and PK behavior and bioavailability were compared for the 2 preparations. All 30 infants enrolled were prescribed ACET for postimmunization prophylaxis. PK samples were available in 27 of the 30 enrolled infants. Subject enrollment (completed in January 1995) was rapid (8.3 months) and drawn entirely from a vaccinated infant clinic population. There were no statistically significant differences between the subjects (elixir, n = 12; suppository, n = 15) in either mean (SD) age (10.0 [6.3] vs 12.4 [8.1] months), weight (8.6 [2.3] vs 9.4 [2.4] kg), sex (7 of 12 males vs 7 of 15 males), or racial distribution (5 white, 5 black, and 2 biracial vs 4 white and 11 black) between the 2 dosing groups (oral vs rectal, respectively). The oral and rectal preparations produced similar, rapid peak concentrations (T(max), 1.16 vs 1.17 hours; P = 0.98) and elimination t(½) (1.84 vs 2.10 hours; P = 0.14), respectively. No statistically significant differences were found between either C(max) (7.65 vs 5.68 μg/mL) or total drug exposure (AUC(0-∞), 23.36 vs 20.45 μg-h/mL) for the oral versus rectal preparations

  16. Ramucirumab for Treating Advanced Gastric Cancer or Gastro-Oesophageal Junction Adenocarcinoma Previously Treated with Chemotherapy: An Evidence Review Group Perspective of a NICE Single Technology Appraisal.

    Science.gov (United States)

    Büyükkaramikli, Nasuh C; Blommestein, Hedwig M; Riemsma, Rob; Armstrong, Nigel; Clay, Fiona J; Ross, Janine; Worthy, Gill; Severens, Johan; Kleijnen, Jos; Al, Maiwenn J

    2017-12-01

    The National Institute for Health and Care Excellence (NICE) invited the company that manufactures ramucirumab (Cyramza ® , Eli Lilly and Company) to submit evidence of the clinical and cost effectiveness of the drug administered alone (monotherapy) or with paclitaxel (combination therapy) for treating adults with advanced gastric cancer or gastro-oesophageal junction (GC/GOJ) adenocarcinoma that were previously treated with chemotherapy, as part of the Institute's single technology appraisal (STA) process. Kleijnen Systematic Reviews Ltd (KSR), in collaboration with Erasmus University Rotterdam, was commissioned to act as the Evidence Review Group (ERG). This paper describes the company's submission, the ERG review, and NICE's subsequent decisions. Clinical effectiveness evidence for ramucirumab monotherapy (RAM), compared with best supportive care (BSC), was based on data from the REGARD trial. Clinical effectiveness evidence for ramucirumab combination therapy (RAM + PAC), compared with paclitaxel monotherapy (PAC), was based on data from the RAINBOW trial. In addition, the company undertook a network meta-analysis (NMA) to compare RAM + PAC with BSC and docetaxel. Cost-effectiveness evidence of monotherapy and combination therapy relied on partitioned survival, cost-utility models. The base-case incremental cost-effectiveness ratio (ICER) of the company was £188,640 (vs BSC) per quality-adjusted life-year (QALY) gained for monotherapy and £118,209 (vs BSC) per QALY gained for combination therapy. The ERG assessment indicated that the modelling structure represented the course of the disease; however, a few errors were identified and some of the input parameters were challenged. The ERG provided a new base case, with ICERs (vs BSC) of £188,100 (monotherapy) per QALY gained and £129,400 (combination therapy) per QALY gained and conducted additional exploratory analyses. The NICE Appraisal Committee (AC), considered the company's decision problem was in

  17. Avelumab in patients with chemotherapy-refractory metastatic Merkel cell carcinoma: a multicentre, single-group, open-label, phase 2 trial.

    Science.gov (United States)

    Kaufman, Howard L; Russell, Jeffery; Hamid, Omid; Bhatia, Shailender; Terheyden, Patrick; D'Angelo, Sandra P; Shih, Kent C; Lebbé, Céleste; Linette, Gerald P; Milella, Michele; Brownell, Isaac; Lewis, Karl D; Lorch, Jochen H; Chin, Kevin; Mahnke, Lisa; von Heydebreck, Anja; Cuillerot, Jean-Marie; Nghiem, Paul

    2016-10-01

    Merkel cell carcinoma is a rare, aggressive skin cancer with poor prognosis in patients with advanced disease. Current standard care uses various cytotoxic chemotherapy regimens, but responses are seldom durable. Tumour oncogenesis is linked to Merkel cell polyomavirus integration and ultraviolet-radiation-induced mutations, providing rationale for treatment with immunotherapy antibodies that target the PD-L1/PD-1 pathway. We assessed treatment with avelumab, an anti-PD-L1 monoclonal antibody, in patients with stage IV Merkel cell carcinoma that had progressed after cytotoxic chemotherapy. In this multicentre, international, prospective, single-group, open-label, phase 2 trial, patients with stage IV chemotherapy-refractory, histologically confirmed Merkel cell carcinoma (aged ≥18 years) were enrolled from 35 cancer treatment centres and academic hospitals in North America, Europe, Australia, and Asia. Key eligibility criteria were an ECOG performance status of 0 or 1, measurable disease by Response Evaluation Criteria in Solid Tumors (RECIST) version 1.1, adequate haematological, hepatic, and renal function, and immune-competent status (patients with HIV, immunosuppression, haematological malignancies, and previous organ transplantation were excluded). Patient selection was not based on PD-L1 expression or Merkel cell polyomavirus status. Collection of biopsy material or use of archival tissue for these assessments was mandatory. Avelumab was given intravenously at a dose of 10 mg/kg every 2 weeks. The primary endpoint was confirmed objective response (complete response or partial response) assessed according to RECIST version 1.1 by an independent review committee. Safety and clinical activity were assessed in all patients who received at least one dose of study drug (the modified intention-to-treat population). This trial is registered with ClinicalTrials.gov as NCT02155647. Between July 25, 2014, and Sept 3, 2015, 88 patients were enrolled and received at

  18. States characterized by the irreducible single row representations of the U(3) is contained in SO(3) and U(4) is contained in Dsup(3/2)[SO(3)] chains of groups

    International Nuclear Information System (INIS)

    Dumitrescu, T.S.

    1977-01-01

    A new method is applied in order to obtain the irreducible single row representations of the groups under study. For the case U(3) contained in SO(3) also an explicit realization is constructed. The method has the advantage of being simpler than the previously used ones. (author)

  19. Pegylated Liposomal Irinotecan Hydrochloride Trihydrate for Treating Pancreatic Cancer After Gemcitabine: An Evidence Review Group Perspective of a NICE Single Technology Appraisal.

    Science.gov (United States)

    Fleeman, Nigel; Abdulla, Ahmed; Bagust, Adrian; Beale, Sophie; Richardson, Marty; Stainthorpe, Angela; Boland, Angela; Kotas, Eleanor; McEntee, Joanne; Palmer, Daniel

    2018-03-01

    The National Institute for Health and Care Excellence (NICE) invited the manufacturer (Shire Pharmaceuticals) of pegylated liposomal irinotecan hydrochloride trihydrate (liposomal irinotecan) to submit clinical and cost-effectiveness evidence for its use in combination with 5-fluorouracil (5-FU) and folic acid/leucovorin (LV) for treating patients with pancreatic cancer following prior treatment with gemcitabine as part of the institute's Single Technology Appraisal process. The Liverpool Reviews and Implementation Group at the University of Liverpool was commissioned to act as the Evidence Review Group (ERG). This article presents a summary of the company's evidence, the ERG review and the resulting NICE guidance (TA440), issued on 26 April 2017. Clinical evidence for liposomal irinotecan + 5-FU/LV versus 5-FU/LV was derived from 236 patients with metastatic pancreatic cancer in the multinational, open-label, randomised controlled NAPOLI-1 trial. Results from analyses of progression-free survival and overall survival showed statistically significant improvements for patients treated with liposomal irinotecan + 5-FU/LV compared with those treated with 5-FU/LV. However, 5-FU/LV alone is rarely used in National Health Service clinical practice for patients with metastatic pancreatic cancer previously treated with gemcitabine. The company, ERG and Appraisal Committee (AC) all agreed that oxaliplatin + 5-FU/LV is the most commonly used treatment. Oxaliplatin + 5-FU/LV was compared with 5-FU/LV in two trials identified by the company. However, the company and the ERG both considered attempts to compare the efficacy of liposomal irinotecan + 5-FU/LV with oxaliplatin + 5-FU/LV to be methodologically flawed; not only was there heterogeneity between trials and their populations but also the proportional hazards assumption required to conduct a robust indirect treatment comparison (ITC) was violated. Nonetheless, data derived from an ITC were used to inform the

  20. Aflatoxins, hydroxylated metabolites, and aflatoxicol from breast muscle of laying hens.

    Science.gov (United States)

    Díaz-Zaragoza, M; Carvajal-Moreno, M; Méndez-Ramírez, I; Chilpa-Galván, N C; Avila-González, E; Flores-Ortiz, C M

    2014-12-01

    Aflatoxins (AF) are toxic fungal secondary metabolites that are pathological to animals and humans. This study identified and quantified AF (AFB(1), AFB(2), AFG(1), AFG(2)) and their hydroxylated metabolites (AFM(1), AFM(2), AFP(1)) and aflatoxicol (AFL) from laying hen breast muscles. Aflatoxins pass from cereal feed to the laying hen tissues, causing economic losses, and from there to humans. To detect the passage of AF from feed to hen breast muscle tissues, an experiment that included 25 Hy-Line W36 121-wk-old hens was performed for 8 d. Hens in individual cages were distributed into 3 groups: a control group, with feed free of AFB(1), and 2 experimental groups, with feed spiked with 2 AFB(1) dosages: 30 µg·kg(-1) (low) or 500 µg·kg(-1) (high). The daily feed consumption per hen was recorded and afterward hens were euthanized and breast muscles were collected, weighed, and dried individually. Aflatoxins were extracted by 2 chemical methods and quantified by HPLC. Both methods were validated by lineality (calibration curves), recovery percentage (>80%), limit of detection, and limit of quantification. The AF (µg·kg(-1)) averages recovered in control breast muscles were as follows: AFB(1) (18); AFG(1), AFM(2), and AFL (0); AFG(2) (1.3); AFM(1) (52), and AFP1 (79). Hens fed with feed spiked with 30 µg·kg(-1) of AFB(1) had AFG(1) (16); AFG(2) (72); AFM(1) (0); AFM(2) (18); AFP(1) (145); and AFL (5 µg·kg(-1)). Hens with feed spiked with 500 µg·kg(-1) of AFB(1) had AFG(1) (512); AFG(2) (7); AFM(1) (4,775); AFM(2) (0); AFP(1) (661); and AFL (21 µg·kg(-1)). The best AF extraction method was Qian and Yang's method, modified by adding additional AF from both Supelclean LC18 SPE columns; its limit of detection (0.5 ng·mL(-1)) was lower compared with that of Koeltzow and Tanner, which was 1 ng·mL(-1). ©2014 Poultry Science Association Inc.

  1. New model system for testing effects of flavonoids on doxorubicin-related formation of hydroxyl radicals

    Czech Academy of Sciences Publication Activity Database

    Souček, P.; Kondrová, E.; Heřmánek, J.; Stopka, Pavel; Boumendjel, A.; Ueng, YF.; Gut, I.

    2011-01-01

    Roč. 22, č. 2 (2011), s. 176-184 ISSN 0959-4973 Institutional research plan: CEZ:AV0Z40320502 Keywords : doxorubicin * electron spin resonance * flavonoids hydroxyl radicals Subject RIV: FD - Oncology ; Hematology Impact factor: 2.407, year: 2011

  2. Fetal exposure to PCBs and their hydroxylated metabolites in a Dutch cohort

    NARCIS (Netherlands)

    Soechitram, S.D.; Athanasiadou, M.; Hovander, L.; Bergman, A.; Sauer, P. J. J.

    2004-01-01

    Polychlorinated biphenyls (PCBs) are still the most abundant pollutants in wildlife and humans. Hydroxylated PCB metabolites (OH-PCBs) are known to be formed in humans and wildlife. Studies in animals show that these metabolites cause endocrine-related toxicity. The health effects in humans have not

  3. Biological production of hydroxylated aromatics : Optimization strategies for Pseudomonas putida S12

    NARCIS (Netherlands)

    Verhoef, A.

    2010-01-01

    To replace environmentally unfriendly petrochemical production processes, the demand for bio-based production of organic chemicals is increasing. This thesis focuses on the biological production of hydroxylated aromatics from renewable substrates by engineered P. putida S12 including several cases

  4. Prediction of hydroxyl concentrations in cement pore water using a numerical cement hydration model

    NARCIS (Netherlands)

    Eijk, van R.J.; Brouwers, H.J.H.

    2000-01-01

    In this paper, a 3D numerical cement hydration model is used for predicting alkali and hydroxyl concentrations in cement pore water. First, this numerical model is calibrated for Dutch cement employing both chemical shrinkage and calorimetric experiments. Secondly, the strength development of some

  5. Formation of 5,6-dihydroxydihydrothymine-type products in DNA by hydroxyl radicals

    International Nuclear Information System (INIS)

    Remsen, J.F.; Roti, J.L.R.

    1977-01-01

    The purpose of the study is to determine whether 5,6-dihydroxydihydrothymine type products in purified DNA and in intact cells results from direct or indirect action and, if indirect, which radical species is primarily responsible. It is concluded that hydroxyl radical is primarily responsible. (U.K.)

  6. Modeling the thermostability of surface functionalisation by oxygen, hydroxyl, and water on nanodiamonds.

    Science.gov (United States)

    Lai, Lin; Barnard, Amanda S

    2011-06-01

    Understanding nanodiamond functionalisation is of great importance for biological and medical applications. Here we examine the stabilities of oxygen, hydroxyl, and water functionalisation of the nanodiamonds using the self-consistent charge density functional tight-binding simulations. We find that the oxygen and hydroxyl termination are thermodynamically favourable and form strong C–O covalent bonds on the nanodiamond surface in an O2 and H2 gas reservoir, which confirms previous experiments. Yet, the thermodynamic stabilities of oxygen and hydroxyl functionalisation decrease dramatically in a water vapour reservoir. In contrast, H2O molecules are found to be physically adsorbed on the nanodiamond surface, and forced chemical adsorption results in decomposition of H2O. Moreover, the functionalisation efficiency is found to be facet dependent. The oxygen functionalisation prefers the {100} facets as opposed to alternative facets in an O2 and H2 gas reservoir. The hydroxyl functionalisation favors the {111} surfaces in an O2 and H2 reservoir and the {100} facets in a water vapour reservoir, respectively. This facet selectivity is found to be largely dependent upon the environmental temperature, chemical reservoir, and morphology of the nanodiamonds.

  7. Infrared Emission Spectrum of the Hydroxyl Radical: A Novel Experiment in Molecular Spectroscopy.

    Science.gov (United States)

    Henderson, Giles; And Others

    1982-01-01

    Describes an experiment in which parameters from an "ab-initio" potential are used to calculate vibrational-rotational energy levels and construct a "stick spectrum" for the overtone emission of the hydroxyl radical. Provides background information on ab-initio spectrum, experimental procedures, and analysis of data. (Author/JN)

  8. Gold-catalyzed Alkyne Hydroxylation: Synthesis of 2-Substituted Benzo[b]furan Compounds

    Institute of Scientific and Technical Information of China (English)

    ZHANG Yuan; XIN Zhi-Jun; XUE Ji-Jun; LI Ying

    2008-01-01

    A strategy concerning the synthesis of 2-substituted benzo[b]furan compounds from o-alkynyl phenols via a gold-catalyzed alkyne hydroxylation is described, which allows the rapid synthesis of various 2-substituted benzo[b]furan derivatives in excellent yields under mild conditions. The o-alkynyl phenol precursors were readily prepared with a Sonogashira coupling reaction.

  9. DNA radiolysis in DNA-protein complex: a stochastic simulation of attack by hydroxyl radicals

    Czech Academy of Sciences Publication Activity Database

    Běgusová, Marie; Giliberto, S.; Gras, J.; Sy, D.; Charlier, M.; Spotheim Maurizot, M.

    2003-01-01

    Roč. 79, č. 6 (2003), s. 385-391 ISSN 0955-3002 R&D Projects: GA AV ČR IAA1048103 Institutional research plan: CEZ:AV0Z1048901 Keywords : radiolysis * DNA-protein complexes * hydroxyl radicals Subject RIV: BO - Biophysics Impact factor: 2.165, year: 2003

  10. Progress modelling of aqueous electrons and hydroxyl radicals in RAIM code

    Energy Technology Data Exchange (ETDEWEB)

    Kim, A Yeong; Kim, Han-Chul; Lee, Jongseong [Korea Institute of Nuclear Safety, Daejeon (Korea, Republic of)

    2015-10-15

    In this paper, the RAIM code was revised minutely with regards to aqueous electrons and hydroxyl radicals, and simulated the P10T2 test. The recent study indicated that the RAIM had the potential for improvement of simulating the iodine behavior influenced by water radiolysis products such as aqueous electrons and hydroxyl radicals. In the existing RAIM modelling, it was considered that aqueous electrons only interacted with oxygen as a consumption reaction, but the reaction with hydrogen peroxide also could be major contributor to the iodine behavior as well as the consumption reaction of aqueous electrons. In case of hydroxyl radicals, RAIM took no notice of the pH impact. In other words, it dealt with the consumption reaction constants but not as a variable of pH. In this communication, the procedures to develop the model related to aqueous electrons and hydroxyl radicals in RAIM will be addressed. And the upgraded RAIM (RAIM-1, 2, 3) codes were applied to OECD-BIP P10T2 test which showed the effect of pH on the iodine behavior and compared with the existing RAIM1.8.3 code. Comparing with the existing RAIM, the improvement reduced the difference about 10%. However, the absolute difference values that is about one order at pH 10 could not be reduced by this approach.

  11. An experimental study of hydroxyl in quartz using infrared spectroscopy and ion microprobe techniques

    Energy Technology Data Exchange (ETDEWEB)

    Rovetta, M. R.; Blacic, J. D.; Hervig, R. L.; Holloway, J. R.

    1989-05-10

    We have measured the concentrations of hydroxyl, deuterium, Al, Fe, Li,Na, K, and Rb in a natural quartz crystal before and after hydrothermaltreatment at 1.5 GPa and 800/degree/--1050 /degree/C. We employed microbeam infraredspectroscopy and ion probe techniques to avoid impurities trapped in healedcracks and fluid inclusions that might bias a normal bulk analysis.The /ital f//sub H/sub 2// of our experiments were buffered to thehematite-magnetite-(OH)fluid, nickel-nickel oxide-(OH)fluid, oriron-wustite-(OH)fluid phase assemblages. After hydrothermal treatment,the samples contained local concentrations of hydrogen or deuterium ofseveral hundred atoms/10/sup 6/ Si (the starting crystal contained 45 H/10/sup 6/ Si).We did several experiments with Al/sub 2/O/sub 3/ or RbCl added to the sample chargeand found local Al enrichment where the deuterium concentration was highbut no Rb enrichment. Finally, we measured trace elements and hydroxyl in aquartz sample after plastic deformation in a talc furnace assembly; inregions of the sample containing basal and prismatic deformation lamellae(but no visible healed microcracks at 400/times/ optical magnification)hydroxyl had increased to /similar to/200 oO/10/sup 6/ Si with no increase in Al or Fe.Samples enriched in hydroxyl but not Al (including the plastically strainedsample) gave infrared spectra resembling natural amethyst crystals.

  12. Structural Mass Spectrometry of Proteins Using Hydroxyl Radical Based Protein Footprinting

    OpenAIRE

    Wang, Liwen; Chance, Mark R.

    2011-01-01

    Structural MS is a rapidly growing field with many applications in basic research and pharmaceutical drug development. In this feature article the overall technology is described and several examples of how hydroxyl radical based footprinting MS can be used to map interfaces, evaluate protein structure, and identify ligand dependent conformational changes in proteins are described.

  13. Oxygen activation at the plasma membrane: relation between superoxide and hydroxyl radical production by isolated membranes.

    Science.gov (United States)

    Heyno, Eiri; Mary, Véronique; Schopfer, Peter; Krieger-Liszkay, Anja

    2011-07-01

    Production of reactive oxygen species (hydroxyl radicals, superoxide radicals and hydrogen peroxide) was studied using EPR spin-trapping techniques and specific dyes in isolated plasma membranes from the growing and the non-growing zones of hypocotyls and roots of etiolated soybean seedlings as well as coleoptiles and roots of etiolated maize seedlings. NAD(P)H mediated the production of superoxide in all plasma membrane samples. Hydroxyl radicals were only produced by the membranes of the hypocotyl growing zone when a Fenton catalyst (FeEDTA) was present. By contrast, in membranes from other parts of the seedlings a low rate of spontaneous hydroxyl radical formation was observed due to the presence of small amounts of tightly bound peroxidase. It is concluded that apoplastic hydroxyl radical generation depends fully, or for the most part, on peroxidase localized in the cell wall. In soybean plasma membranes from the growing zone of the hypocotyl pharmacological tests showed that the superoxide production could potentially be attributed to the action of at least two enzymes, an NADPH oxidase and, in the presence of menadione, a quinone reductase.

  14. Structure-based engineering of steroidogenic CYP260A1 for stereo- and regioselective hydroxylation of progesterone

    NARCIS (Netherlands)

    Khatri, Yogan; Jóźwik, Ilona K; Ringle, Michael; Ionescu, Irina Alexandra; Litzenburger, Martin; Hutter, Michael Christopher; Thunnissen, Andy-Mark W H; Bernhardt, Rita

    The production of regio- and stereoselectively hydroxylated steroids is of high pharmaceutical interest and can be achieved by cytochrome P450-based biocatalysts. CYP260A1 from Sorangium cellulosum strain So ce56 catalyzes hydroxylation of C19 or C21 steroids at the very unique 1-position. However,

  15. Urocanic acid isomers are good hydroxyl radical scavengers: a comparative study with structural analogues and with uric acid

    NARCIS (Netherlands)

    Kammeyer, A.; Eggelte, T. A.; Bos, J. D.; Teunissen, M. B.

    1999-01-01

    UV-exposure of the epidermis leads to the isomerisation of trans-UCA into cis-UCA as well as to the generation of hydroxyl radicals. This study shows by means of the deoxyribose degradation test that UCA isomers are more powerful hydroxyl radical scavengers than the other 4-(5-)substituted imidazole

  16. Evidence for formation of hydroxyl radicals during reperfusion after global cerebral ischaemia in rats using salicylate trapping and microdialysis

    DEFF Research Database (Denmark)

    Christensen, Thomas; Bruhn, T; Balchen, T

    1994-01-01

    Systemic administration of salicylate (SA) to rats (100 mg kg-1 i.p. ) was used as an in vivo trap of hydroxyl radicals (.OH). In the brain SA reacts with hydroxyl radicals to form the stable adducts 2, 3- and 2,5 dihydroxybenzoic acid (DHBAs) which can thus be taken as an index of .OH formation...

  17. EPR detection of hydroxyl radical generation and its interaction with antioxidant system in Carassius auratus exposed to pentachlorophenol

    Energy Technology Data Exchange (ETDEWEB)

    Luo Yi [Key Laboratory of Pollution Processes and Environmental Criteria (Nankai University), Ministry of Education, College of Environmental Sciences and Engineering, Nankai University, Tianjin 300071 (China); Wang Xiaorong, E-mail: yiyluo@gmail.com [State Key Laboratory of Pollution Control and Resources Reuse, School of Environment, Nanjing University, Nanjing 210093 (China); Ji Liangliang; Su Yan [State Key Laboratory of Pollution Control and Resources Reuse, School of Environment, Nanjing University, Nanjing 210093 (China)

    2009-11-15

    In the present study, direct evidence of hydroxyl radical production in livers of Carassius auratus exposed to pentachlorophenol (PCP) was provided using electron paramagnetic resonance (EPR) with spin-trapping. A dose-effect relationship was obtained between hydroxyl radical intensities and PCP exposure. It was observed that hydroxyl radical was significantly induced by 0.001 mg l{sup -1} (below the criteria for Chinese fishery water quality) of PCP exposure. A strong positive correlation (r = 0.9581, p < 0.001) was observed between PCP liver concentrations and hydroxyl radical intensities within 7 d of PCP exposure, which suggests that hydroxyl radical are mainly produced from PCP itself. However, no correlation was observed between PCP liver concentrations and hydroxyl radical intensities after 7 d, and a higher intensity of hydroxyl radical could still be observed when the PCP liver concentrations decreased to a lower level, which suggests that other mechanisms may possibly contribute to hydroxyl radical production after 7 d. The glutathione/oxidized glutathione (GSH/GSSG) ratio decreased below that of the control level during the entire period of PCP exposure (0.05 mg l{sup -1}), which suggested oxidative stress occurred.

  18. Comparison of synthesis of 15α-hydroxylated steroids in males of four North American lamprey species

    Science.gov (United States)

    Bryan, Mara B.; Young, Bradley A.; Close, David A.; Semeyn, Jesse; Robinson, T. Craig; Bayer, Jennifer M.; Li, Weiming

    2006-01-01

    Recent studies have provided evidence that 15α-hydroxytestosterone (15α-T) and 15α-hydroxyprogesterone (15α-P) are produced in vitro and in vivo in adult male sea lampreys (Petromyzonmarinus), and that circulatory levels increase in response to injections with gonadotropin-releasing hormone (GnRH). We examined four species from the Petromyzontidae family including silver lampreys (Ichthyomyzon unicuspis), chestnut lampreys (I. castaneus), American brook lampreys (Lethenteron appendix), and Pacific lampreys (Entosphenus tridentatus) to determine if these unusual steroids were unique to sea lampreys or a common feature in lamprey species. In vitro production was examined through incubations of testis with tritiated precursors, and 15α-T and 15α-P production was confirmed in all species through co-elution with standards on both high performance liquid chromatography (HPLC) and thin layerchromatography. In vivo production was proven by demonstrating that HPLC-fractionated plasma had peaks of immunoreactive 15α-T and 15α-P that co-eluted with standards through using previously developed radioimmunoassays for 15α-T and 15α-P. The possible functionality of 15α-T and 15α-P was further examined in silver and Pacific lampreys by investigating the effect of injection of either type of lamprey GnRH on plasma concentrations of 15α-T and 15α-P. Injections with exogenous GnRH did not affect circulatory levels of either steroid in silver lampreys, and only GnRH III elicited higher levels of both steroids in Pacific lampreys. The 15α-hydroxylase enzyme(s) for steroids appeared to present in adult males of all species examined, but the question of whether 15α-hydroxylated steroids are functional in these lamprey species, and the significance of the 15-hydroxyl group, requires further research.

  19. Steroid hydroxylations: A paradigm for cytochrome P450 catalyzed mammalian monooxygenation reactions

    International Nuclear Information System (INIS)

    Estabrook, Ronald W.

    2005-01-01

    The present article reviews the history of research on the hydroxylation of steroid hormones as catalyzed by enzymes present in mammalian tissues. The report describes how studies of steroid hormone synthesis have played a central role in the discovery of the monooxygenase functions of the cytochrome P450s. Studies of steroid hydroxylation reactions can be credited with showing that: (a) the adrenal mitochondrial enzyme catalyzing the 11β-hydroxylation of deoxycorticosterone was the first mammalian enzyme shown by O 18 studies to be an oxygenase; (b) the adrenal microsomal enzyme catalyzing the 21-hydroxylation of steroids was the first mammalian enzyme to show experimentally the proposed 1:1:1 stoichiometry (substrate:oxygen:reduced pyridine nucleotide) of a monooxygenase reaction; (c) application of the photochemical action spectrum technique for reversal of carbon monoxide inhibition of the 21-hydroxylation of 17α-OH progesterone was the first demonstration that cytochrome P450 was an oxygenase; (d) spectrophotometric studies of the binding of 17α-OH progesterone to bovine adrenal microsomal P450 revealed the first step in the cyclic reaction scheme of P450, as it catalyzes the 'activation' of oxygen in a monooxygenase reaction; (e) purified adrenodoxin was shown to function as an electron transport component of the adrenal mitochondrial monooxygenase system required for the activity of the 11β-hydroxylase reaction. Adrenodoxin was the first iron-sulfur protein isolated and purified from mammalian tissues and the first soluble protein identified as a reductase of a P450; (f) fractionation of adrenal mitochondrial P450 and incubation with adrenodoxin and a cytosolic (flavoprotein) fraction were the first demonstration of the reconstitution of a mammalian P450 monooxygenase reaction

  20. Evaluating the efficacy of the current diagnosis-related group reimbursement system for laparoscopic appendectomy at a single institute in Korea

    OpenAIRE

    Yoo, Ri Na; Chung, Chul-Woon; Kim, Jong-Woo

    2014-01-01

    Purpose The diagnosis-related group (DRG) system has been adapted to reduce overall medical costs by grouping and classifying relatively homogenous patients based on similar resource consumption patterns in the treatment. However, despite its wide range of disease manifestation from early inflammation to severe peritonitis, acute appendicitis is included in the DRG system. Responding to a need to assess the DRG system for patients diagnosed with appendicitis, this study evaluates the efficacy...

  1. Retarded Local Dynamics of Single Fluorescent Probes in Polymeric Glass due to Interaction Strengthening

    Science.gov (United States)

    Zhang, Hao; Yang, Jingfa; Zhao, Jiang

    The effect of strengthening of interaction between single fluorescent probes and polymer matrix to the probes dynamics is investigated using single molecule fluorescence defocus microscopy. By introducing multiple hydroxyl groups to the fluorescent probes, which builds up hydrogen bonds between the probe and polymer matrix, the dynamics is discovered to be retarded. This is evidenced by the lowering of the frequency of the vibrational modes in the power spectra of the rotation trajectories of individual fluorescent probes, and also by the lowering of population of rotating probes. The results show that by strengthening the probe-matrix interaction, the local dynamics detected by the probes is equivalent to that detected by a bigger probe, due to the enhanced friction between the probe and the polymer matrix. the National Basic Research Program of China (2012CB821500).

  2. Daily electronic self-monitoring in bipolar disorder using smartphones - the MONARCA I trial: a randomized, placebo-controlled, single-blind, parallel group trial.

    Science.gov (United States)

    Faurholt-Jepsen, M; Frost, M; Ritz, C; Christensen, E M; Jacoby, A S; Mikkelsen, R L; Knorr, U; Bardram, J E; Vinberg, M; Kessing, L V

    2015-10-01

    The number of studies on electronic self-monitoring in affective disorder and other psychiatric disorders is increasing and indicates high patient acceptance and adherence. Nevertheless, the effect of electronic self-monitoring in patients with bipolar disorder has never been investigated in a randomized controlled trial (RCT). The objective of this trial was to investigate in a RCT whether the use of daily electronic self-monitoring using smartphones reduces depressive and manic symptoms in patients with bipolar disorder. A total of 78 patients with bipolar disorder according to ICD-10 criteria, aged 18-60 years, and with 17-item Hamilton Depression Rating Scale (HAMD-17) and Young Mania Rating Scale (YMRS) scores ≤17 were randomized to the use of a smartphone for daily self-monitoring including a clinical feedback loop (the intervention group) or to the use of a smartphone for normal communicative purposes (the control group) for 6 months. The primary outcomes were differences in depressive and manic symptoms measured using HAMD-17 and YMRS, respectively, between the intervention and control groups. Intention-to-treat analyses using linear mixed models showed no significant effects of daily self-monitoring using smartphones on depressive as well as manic symptoms. There was a tendency towards more sustained depressive symptoms in the intervention group (B = 2.02, 95% confidence interval -0.13 to 4.17, p = 0.066). Sub-group analysis among patients without mixed symptoms and patients with presence of depressive and manic symptoms showed significantly more depressive symptoms and fewer manic symptoms during the trial period in the intervention group. These results highlight that electronic self-monitoring, although intuitive and appealing, needs critical consideration and further clarification before it is implemented as a clinical tool.

  3. Single-Cell Genome and Group-Specific dsrAB Sequencing Implicate Marine Members of the Class Dehalococcoidia (Phylum Chloroflexi) in Sulfur Cycling

    DEFF Research Database (Denmark)

    Wasmund, Kenneth; Cooper, Myriel; Schreiber, Lars

    2016-01-01

    The marine subsurface sediment biosphere is widely inhabited by bacteria affiliated with the class Dehalococcoidia (DEH), phylum Chloroflexi, and yet little is known regarding their metabolisms. In this report, genomic content from a single DEH cell (DEH-C11) with a 16S rRNA gene that was affilia......The marine subsurface sediment biosphere is widely inhabited by bacteria affiliated with the class Dehalococcoidia (DEH), phylum Chloroflexi, and yet little is known regarding their metabolisms. In this report, genomic content from a single DEH cell (DEH-C11) with a 16S rRNA gene...... that was affiliated with a diverse cluster of 16S rRNA gene sequences prevalent in marine sediments was obtained from sediments of Aarhus Bay, Denmark. The distinctive gene content of this cell suggests metabolic characteristics that differ from those of known DEH and Chloroflexi. The presence of genes encoding...... dissimilatory sulfite reductase (Dsr) suggests that DEH could respire oxidized sulfur compounds, although Chloroflexi have never been implicated in this mode of sulfur cycling. Using long-range PCR assays targeting DEH dsr loci, dsrAB genes were amplified and sequenced from various marine sediments. Many...

  4. Area G perimeter surface-soil and single-stage water sampling: Environmental surveillance for fiscal year 94, Group ESH-19. Progress report

    International Nuclear Information System (INIS)

    Conrad, R.; Childs, M.; Lyons, C.R.; Coriz, F.

    1996-08-01

    ESH-19 personnel collected soil and single-stage water samples around the perimeter of Area G at Los Alamos National Laboratory during FY94 to characterize possible contaminant movement out of Area G through surface-water and sediment runoff. These samples were analyzed for tritium, total uranium, isotopic plutonium, americium-241, and cesium-137. Ten metals were also analyzed on selected soils using analytical laboratory techniques. All radiochemical data are compared with analogous samples collected during FY 93 and reported in LA-12986. Baseline concentrations for future disposal operations were established for metals and radionuclides by a sampling program in the proposed Area G Expansion Area. Considering the amount of radioactive waste that has been disposed at Area G, there is evidence of only low concentrations of radionuclides on perimeter surface soils. Consequently, little radioactivity is leaving the confines of Area G via the surface water runoff pathway

  5. Controlling the Morphology of BDTT-DPP-Based Small Molecules via End-Group Functionalization for Highly Efficient Single and Tandem Organic Photovoltaic Cells.

    Science.gov (United States)

    Kim, Ji-Hoon; Park, Jong Baek; Yang, Hoichang; Jung, In Hwan; Yoon, Sung Cheol; Kim, Dongwook; Hwang, Do-Hoon

    2015-11-04

    A series of narrow-band gap, π-conjugated small molecules based on diketopyrrolopyrrole (DPP) electron acceptor units coupled with alkylthienyl-substituted-benzodithiophene (BDTT) electron donors were designed and synthesized for use as donor materials in solution-processed organic photovoltaic cells. In particular, by end-group functionalization of the small molecules with fluorine derivatives, the nanoscale morphologies of the photoactive layers of the photovoltaic cells were successfully controlled. The influences of different fluorine-based end-groups on the optoelectronic and morphological properties, carrier mobilities, and the photovoltaic performances of these materials were investigated. A high power conversion efficiency (PCE) of 6.00% under simulated solar light (AM 1.5G) illumination has been achieved for organic photovoltaic cells based on a small-molecule bulk heterojunction system consisting of a trifluoromethylbenzene (CF3) end-group-containing oligomer (BDTT-(DPP)2-CF3) as the donor and [6,6]-phenyl-C71-butyric acid methyl ester (PC71BM) as the acceptor. As a result, the introduction of CF3 end-groups has been found to enhance both the short circuit current density (JSC) and fill factor (FF). A tandem photovoltaic device comprising an inverted BDTT-(DPP)2-CF3:PC71BM cell and a poly(3-hexylthiophene) (P3HT):indene-C60-bisadduct (IC60BA)-based cell as the top and bottom cell components, respectively, showed a maximum PCE of 8.30%. These results provide valuable guidelines for the rational design of conjugated small molecules for applications in high-performance organic photovoltaic cells. Furthermore, to the best of our knowledge, this is the first report on the design of fluorine-functionalized BDTT-DPP-based small molecules, which have been shown to be a viable candidate for use in inverted tandem cells.

  6. Pectic polysaccharides are attacked by hydroxyl radicals in ripening fruit: evidence from a fluorescent fingerprinting method.

    Science.gov (United States)

    Airianah, Othman B; Vreeburg, Robert A M; Fry, Stephen C

    2016-03-01

    Many fruits soften during ripening, which is important commercially and in rendering the fruit attractive to seed-dispersing animals. Cell-wall polysaccharide hydrolases may contribute to softening, but sometimes appear to be absent. An alternative hypothesis is that hydroxyl radicals ((•)OH) non-enzymically cleave wall polysaccharides. We evaluated this hypothesis by using a new fluorescent labelling procedure to 'fingerprint' (•)OH-attacked polysaccharides. We tagged fruit polysaccharides with 2-(isopropylamino)-acridone (pAMAC) groups to detect (a) any mid-chain glycosulose residues formed in vivo during (•)OH action and (b) the conventional reducing termini. The pAMAC-labelled pectins were digested with Driselase, and the products resolved by high-voltage electrophoresis and high-pressure liquid chromatography. Strawberry, pear, mango, banana, apple, avocado, Arbutus unedo, plum and nectarine pectins all yielded several pAMAC-labelled products. GalA-pAMAC (monomeric galacturonate, labelled with pAMAC at carbon-1) was produced in all species, usually increasing during fruit softening. The six true fruits also gave pAMAC·UA-GalA disaccharides (where pAMAC·UA is an unspecified uronate, labelled at a position other than carbon-1), with yields increasing during softening. Among false fruits, apple and strawberry gave little pAMAC·UA-GalA; pear produced it transiently. GalA-pAMAC arises from pectic reducing termini, formed by any of three proposed chain-cleaving agents ((•)OH, endopolygalacturonase and pectate lyase), any of which could cause its ripening-related increase. In contrast, pAMAC·UA-GalA conjugates are diagnostic of mid-chain oxidation of pectins by (•)OH. The evidence shows that (•)OH radicals do indeed attack fruit cell wall polysaccharides non-enzymically during softening in vivo. This applies much more prominently to drupes and berries (true fruits) than to false fruits (swollen receptacles). (•)OH radical attack on polysaccharides

  7. Hydroxyl-Containing Aromatic Polyimides for Carbon Dioxide Removal from Natural Gas

    KAUST Repository

    Alaslai, Nasser Y.

    2017-10-01

    Natural gas is among the most dominant resources to provide energy supplies and Saudi Arabia ranks among the top 5 producers worldwide. However, prior to use of methane, natural gas has to be treated to remove other feed gas components, such as H2O, CO2, H2S, N2 and C2+ hydrocarbons. Most NG fields in KSA contain about 10 mol% carbon dioxide that has to be reduced to less than 2 mol% for pipeline delivery. The conventional unit operations for natural gas separations, that is, molecular sieves, amine absorption, cryogenic distillation, and turbo expansion exhibit some disadvantages in terms of economics, operational flexibility or system footprint. One of the most attractive alternative is membrane technology in either standalone- or hybrid system configuration. Currently, the only two membrane materials used in industrial natural gas applications are cellulose acetate and polyimide, which have moderate permeability and fairly low selectivity when tested under realistic industrial conditions. The goal for future research is to develop unique polymeric membranes, which can at least partially replace conventional gas processing in future natural gas projects. This will support global economics and specifically the economy of Saudi Arabia. Newly developed polymeric materials must meet certain criteria to be used on a commercial scale. These criteria include: (i) high permeability and selectivity, (ii) processability into thin films, (iii) mechanical and thermal stability, and (iv) chemical stability against feed gas components. This project focused on the removal of carbon dioxide from natural gas by developing and characterizing functionalized aromatic polyimide membrane materials that exhibit very high selectivity under aggressive mixed-gas conditions. 6FDA-DAR demonstrated a mixed-gas CO2/CH4 selectivity of 78 at a CO2 partial pressure of 10 bar with no pronounced indication of plasticization. Combining hydroxyl- and carboxyl groups in a miscible polyimide blend led

  8. Enhanced adsorption of hydroxyl contained/anionic dyes on non functionalized Ni@SiO{sub 2} core–shell nanoparticles: Kinetic and thermodynamic profile

    Energy Technology Data Exchange (ETDEWEB)

    Jiang, Zhifeng, E-mail: ntjiangzf@sina.com; Xie, Jimin, E-mail: xiejm391@sohu.com; Jiang, Deli, E-mail: jiangdeli100@yahoo.com; Yan, Zaoxue, E-mail: yanzaoxue@163.com; Jing, Junjie, E-mail: jingjj1975@163.com; Liu, Dong, E-mail: 919457966@qq.com

    2014-02-15

    A green and low-cost adsorbent with both magnetic property and high adsorption capacity was prepared on the basis of nickel magnetic core with silica shell. The surface of the prepared Ni@SiO{sub 2} composite was not modified. The influence of different functional groups and different charged of the dyes on the adsorption process on the non functionalized Ni@SiO{sub 2} have been studied. The results indicated that synthesized adsorbent exhibited higher adsorption capacity for dyes with negative charge/hydroxyl groups as compared to dyes with positive charge/without hydroxyl groups due to the hydrogen bonding interaction and electrostatic interaction between the adsorbent and dyes. Adsorption kinetics and isotherms experiments were carried out and the results indicated that the adsorption process was fitted by pseudo second order kinetics and Freundlich model. The binding of these dyes with magnetic adsorbent surface mainly involves physical adsorption according to D–R model. Furthermore, the adsorption process is spontaneous and endothermic as studied from adsorption thermodynamics. The value of ΔH° and mean free energy further confirmed that physical adsorption is the major adsorption process. After regeneration, the adsorbent still shows high adsorption capacity even for 4 cycles of desorption–adsorption.

  9. Stability, electrochemical behaviors and electronic structures of iron hydroxyl-phosphate

    International Nuclear Information System (INIS)

    Wang Zhongli; Sun Shaorui; Li Fan; Chen Ge; Xia Dingguo; Zhao Ting; Chu Wangsheng; Wu Ziyu

    2010-01-01

    Iron hydroxyl-phosphate with a uniform spherical particle size of around 1 μm, a compound of the type Fe 2-y □ y (PO 4 )(OH) 3-3y (H 2 O) 3y-2 (where □ represents a vacancy), has been synthesized by hydrothermal methods. The particles are composed of spheres of diameter -1 and 120 mAh g -1 at current densities of 170 mA g -1 and 680 mA g -1 , respectively. The stability of crystal structure of this material was studied by TGA and XRD which show that the material remains stable at least up to the temperature 200 deg. C. Investigation of the electronic structure of the iron hydroxyl-phosphate by GGA + U calculation has indicated that it has a better electronic conductivity than LiFePO 4 .

  10. Effect of nitrogen doping of graphene oxide on hydrogen and hydroxyl adsorption

    Energy Technology Data Exchange (ETDEWEB)

    Min, Byeong June; Jeong, Hae Kyung [Daegu University, Kyungsan (Korea, Republic of)

    2014-05-15

    We investigate how nitrogen-doping affects the hydrogen (H) and the hydroxyl (OH) adsorption on graphene oxide (GO) and on nitrogen-doped GO (NGO) via pseudopotential plane wave density functional calculations within the local spin density approximation. We find that the nitrogen doping brings about drastic changes in the hydrogen and the hydroxyl adsorption energetics, but its effects depend sensitively on the nitrogen configuration in NGO. The H and the OH adsorption energies are comparable only for pyrrolic NGO. In GO and quarternary NGO, the H adsorption energy is greater than the OH adsorption energy while the trend is reversed in pyridinic NGO. Also, the OH adsorption process is less affected by nitrogen-doping than the H adsorption is.

  11. Properties of the Nafion membrane impregnated with hydroxyl ammonium based ionic liquids

    International Nuclear Information System (INIS)

    Garaev, Valeriy; Pavlovica, Sanita; Vaivars, Guntars; Kleperis, Janis

    2012-01-01

    In this work, the Nafion 112 membrane impregnated with nine various hydroxyl ammonium based ionic liquids have been investigated. The used ionic liquids were combined from hydroxyl ammonium cations (2-hydroxyethylammonium/HEA, bis(2- hydroxyethyl)ammonium/BHEA, tris(2-hydroxyethyl)ammonium/THEA) and carboxylate anions (formate, acetate, lactate). The membranes are characterized by conductivity and thermal stability measurements. It was found, that almost all composites have 10 times higher ion conductivity than a pure Nafion 112 at 90 °C in ambient environment due to the higher thermal stability. The thermal stability of Nafion membrane was increased by all studied nine ionic liquids. In this work, only biodegradable ionic liquids were used for composite preparation.

  12. Study on the plasma reaction process of hydroxyl generation by strong electric field ionization discharge

    International Nuclear Information System (INIS)

    Bai Mindi; Deng Shufang; Bai Xiyao; Zhang Zhitao

    2004-01-01

    Considering the change in the structure of reaction room, dielectric materials and process technology, authors have specifically studied the plasma reaction process of creating hydroxyl radical OH * and e aq - from ionization of O 2 and H 2 O through a strong electric field discharge. The production volume of hydroxyl radical OH * is up to the project application level, and process technology meets the 12 laws of green chemistry, free from environmental pollution from the source. The authors have emphatically researched on the green method of flue gas desulfurization, which will ionize SO 2 , H 2 O and O 2 in the flue gas to synthesis H 2 SO 4 in molecular level within 0.8 s without absorbent and catalyst. (author)

  13. Microbial carbonylation and hydroxylation of 20(R)-panaxadiol by Aspergillus niger.

    Science.gov (United States)

    Yan, Bin; Chen, Zhihua; Zhai, Xuguang; Yin, Guibo; Ai, Yafei; Chen, Guangtong

    2018-04-01

    20(R)-panaxadiol (PD) was metabolised by the fungus Aspergillus niger AS 3.3926 to its C-3 carbonylated metabolite and five other hydroxylated metabolites (1-6). Their structures were elucidated as 3-oxo-20(R)-panaxadiol (1), 3-oxo-7β-hydroxyl- 20(R)-panaxadiol (2), 3-oxo-7β,23α-dihydroxyl-20(R)-panaxadiol (3), 3,12-dioxo- 7β,23β-dihydroxyl-20(R)-panaxadiol (4), 3-oxo-1α,7β-dihydroxyl-20(R)-panaxadiol (5) and 3-oxo-7β,15β-dihydroxyl-20(R)-panaxadiol (6) by spectroscopic analysis. Among them, compounds 2-6 were new compounds. Pharmacological studies revealed that compound 6 exhibited significant anti-hepatic fibrosis activity.

  14. Study of the hydroxyl radical: Experimental advances in microwave spectroscopy, theoretical model and astrophysical consequences

    International Nuclear Information System (INIS)

    Destombes, Jean-Luc

    1978-01-01

    This research thesis mainly addresses the experimental and theoretical study of the hydroxyl radical, and the consequences of the obtained results in astrophysics which are studied with a model of pumping by the far infrared. After a recall of notions related to microwave spectroscopy and to molecular radio-astronomy, the author more particularly discusses different aspects of microwave spectroscopy in the interstellar environment and in laboratory. He also reviews different types of spectrometers for unsteady molecules. In the second part, he addresses issues related to the hydroxyl radical (OH): presentation of spectrometers, study of the reaction environment, study of the radical microwave spectrum, identification of transitions by frequency measurements. In the last parts, the author addresses some aspects of interstellar OH masers, and reports the application of some results to simple models of pumping by the far infra red

  15. Effects of hydroxylated benzaldehyde derivatives on radiation-induced reactions involving various organic radicals

    Science.gov (United States)

    Ksendzova, G. A.; Samovich, S. N.; Sorokin, V. L.; Shadyro, O. I.

    2018-05-01

    In the present paper, the effects of hydroxylated benzaldehyde derivatives and gossypol - the known natural occurring compound - on formation of decomposition products resulting from radiolysis of ethanol and hexane in deaerated and oxygenated solutions were studied. The obtained data enabled the authors to make conclusions about the effects produced by the structure of the compounds under study on their reactivity towards oxygen- and carbon-centered radicals. It has been found that 2,3-dihydroxybenzaldehyde, 4,6-di-tert-butyl-2,3-dihydroxybenzaldehyde and 4,6-di-tert-butyl-3-(1,3-dioxane-2-yl)-1,2-dihydroxybenzene are not inferior in efficiency to butylated hydroxytoluene - the industrial antioxidant - as regards suppression of the radiation-induced oxidation processes occurring in hexane. The derivatives of hydroxylated benzaldehydes were shown to have a significant influence on radiation-induced reactions involving α-hydroxyalkyl radicals.

  16. First principles study of electronic and structural properties of single walled zigzag boron nitride nanotubes doped with the elements of group IV

    Science.gov (United States)

    Bahari, Ali; jalalinejad, Amir; Bagheri, Mosahhar; Amiri, Masoud

    2017-11-01

    In this paper, structural and electronic properties and stability of (10, 0) born nitride nanotube (BNNT) are considered within density functional theory by doping group IV elements of the periodic table. The HOMO-LUMO gap has been strongly modified and treated a dual manner by choosing B or N sites for dopant atoms. Formation energy calculation shows that B site doping is more stable than N site doping. Results also show that all dopants turn the pristine BNNT into a p-type semiconductor except for carbon-doped BNNT at B site.

  17. Outcomes of Total Parathyroidectomy with Autotransplantation versus Subtotal Parathyroidectomy with Routine Addition of Thymectomy to both Groups: Single Center Experience of Secondary Hyperparathyroidism

    Directory of Open Access Journals (Sweden)

    Cem Kaan Parsak

    2014-03-01

    Full Text Available Background: Secondary hyperparathyroidism is a common acquired disorder seen in chronic renal failure. It may result in potentially serious complications including metabolic bone diseases, severe atherosclerosis and undesirable cardiovascular events. Parathyroidectomy is required in about 20% of patients after 3-10 years of dialysis and in up to 40% after 20 years. Aims: The aim of the current study was to evaluate the short-term and long-term outcomes of patients with secondary hyperparathyroidism who had undergone total parathyroidectomy with autotransplantation and thymectomy or subtotal parathyroidectomy with thymectomy by the same surgical team during the study period. Study Design: Retrospective comparative study. Methods: Clinical data of 50 patients who underwent parathyroid surgery for secondary hyperparathyroidism between 2003 and 2011 were reviewed retrospectively. Patients were divided into two subgroups of total parathyroidectomy with autotransplantation or subtotal parathyroidectomy. Thymectomy was routinely performed for both groups. Short term outcome parameters included intact parathyroid hormone, ionized calcium and alkaline phosphatase levels. Bone pain, bone fractures, persistent or recurrent disease were included in long term outcome parameters. Results: The mean duration of dialysis was eight years. The mean ionized calcium levels dropped significantly in the total parathyroidectomy with autotransplantation group (p=0.016. No serious postoperative complications were observed. Postoperative intravenous calcium supplementation was required in four patients in the total parathyroidectomy with autotransplantation group (total PTX+AT and in three patients in the subtotal parathyroidectomy group (subtotal PTX. Postoperatively, all patients received oral calcium carbonate and calcitriol. The length of average hospital stay was 5 (3-10 days. Including nine patients who underwent successful renal transplantation pre-operative bone

  18. A Brief Review on Electro-generated Hydroxyl Radical for Organic Wastewater Mineralization

    Directory of Open Access Journals (Sweden)

    Ervin Nurhayati

    2016-05-01

    Full Text Available Hydroxyl radical is a highly reactive oxidizing agent that can be electrochemically generated on the surface of Boron doped diamond (BDD anode. Once generated, this radical will non-selectively mineralize organic pollutants to carbon dioxide, water and organic anions as the oxidation products. Its application in Advanced Oxidation Process (AOP to degrade nonbiodegradable even the recalcitrant pollutants in wastewater has been increasingly studied and even applied.

  19. Hydroxyl radical-modified fibrinogen as a marker of thrombosis: the role of iron.

    Science.gov (United States)

    Lipinski, B; Pretorius, E

    2012-07-01

    Excessive free iron in blood and in organ tissues (so called iron overload) has been observed in degenerative diseases such as atherosclerosis, cancer, neurological, and certain autoimmune diseases, in which fibrin-like deposits are also found. Although most of the body iron is bound to hemoglobin and myoglobin in a divalent ferrous form, a certain amount of iron exists in blood as a trivalent (ferric) ion. This particular chemical state of iron has been shown to be toxic to the human body when not controlled by endogenous and/or dietary chelating agents. Experiments described in this paper show for the first time that ferric ions (Fe(3+)) can generate hydroxyl radicals without participation of any redox agent, thus making it a special case of the Fenton reaction. Ferric chloride was also demonstrated to induce aggregation of purified fibrinogen at the same molar concentrations that were used for the generation of hydroxyl radicals. Iron-aggregated fibrinogen, by contrast to native molecule, could not be dissociated into polypeptide subunit chains as shown in a polyacrylamide gel electrophoresis. The mechanism of this phenomenon is very likely based on hydroxyl radical-induced modification of fibrinogen tertiary structure with the formation of insoluble aggregates resistant to enzymatic and chemical degradations. Soluble modified fibrinogen species can be determined in blood of thrombotic patients by the reaction with protamine sulfate and/or by scanning electron microscopy. In view of these findings, it is postulated that iron-induced alterations in fibrinogen structure is involved in pathogenesis of certain degenerative diseases associated with iron overload and persistent thrombosis. It is concluded that the detection of hydroxyl radical-modified fibrinogen may be utilized as a marker of a thrombotic condition in human subjects.

  20. Lewis base catalyzed enantioselective allylic hydroxylation of Morita-Baylis-Hillman carbonates with water

    KAUST Repository

    Zhu, Bo

    2011-08-19

    A Lewis base catalyzed allylic hydroxylation of Morita-Baylis-Hillman (MBH) carbonates has been developed. Various chiral MBH alcohols can be synthesized in high yields (up to 99%) and excellent enantioselectivities (up to 94% ee). This is the first report using water as a nucleophile in asymmetric organocatalysis. The nucleophilic role of water has been verified using 18O-labeling experiments. © 2011 American Chemical Society.

  1. Hydroxyl-substituted ladder polyethers via selective tandem epoxidation/cyclization sequence.

    Science.gov (United States)

    Czabaniuk, Lara C; Jamison, Timothy F

    2015-02-20

    A new and highly selective method for the synthesis of hydroxyl-substituted tetrahydropyrans is described. This method utilizes titanium(IV) isopropoxide and diethyl tartrate to perform a diastereoselective epoxidation followed by in situ epoxide activation and highly selective endo-cyclization to form the desired tetrahydropyran ring. The HIJ ring fragment of the marine ladder polyether yessotoxin was synthesized using this two-stage tactic that proceeds with high efficiency and excellent regioselectivity.

  2. Bile acid synthesis in man. In vivo activity of the 25-hydroxylation pathway

    International Nuclear Information System (INIS)

    Duane, W.C.; Pooler, P.A.; Hamilton, J.N.

    1988-01-01

    During biosynthesis of bile acid, carbons 25-26-27 are removed from the cholesterol side-chain. Side-chain oxidation begins either with hydroxylation at the 26-position, in which case the three-carbon fragment is released as propionic acid, or with hydroxylation at the 25-position, in which case the three-carbon fragment is released as acetone. We have previously shown in the rat that the contribution of the 25-hydroxylation pathway can be quantitated in vivo by measuring production of [ 14 C]acetone from [ 14 C]26-cholesterol. In the present study, we adapted this method to human subjects. 4 d after oral administration of 100 microCi of [ 14 C]26-cholesterol and 1 d after beginning a constant infusion of 16.6 mumol/min unlabeled acetone, three men and two women underwent breath collections. Expired acetone was trapped and purified as the 2,4 dinitrophenylhydrazine derivative. 14 CO 2 was trapped quantitatively using phenethylamine. Specific activity of breath acetone was multiplied by the acetone infusion rate to calculate production of [ 14 C]acetone. [ 14 C]Acetone production averaged 4.9% of total release of 14 C from [ 14 C]26-cholesterol, estimated by 14 CO2 output. The method was validated by showing that [ 14 C]acetone production from [ 14 C]isopropanol averaged 86.9% of the [ 14 C]-isopropanol infusion rate. We conclude that in man, as in the rat, the 25-hydroxylation pathway accounts for less than 5% of bile acid synthesis

  3. Photocatalytic Hydrogen-Evolution Cross-Couplings: Benzene C-H Amination and Hydroxylation.

    Science.gov (United States)

    Zheng, Yi-Wen; Chen, Bin; Ye, Pan; Feng, Ke; Wang, Wenguang; Meng, Qing-Yuan; Wu, Li-Zhu; Tung, Chen-Ho

    2016-08-17

    We present a blueprint for aromatic C-H functionalization via a combination of photocatalysis and cobalt catalysis and describe the utility of this strategy for benzene amination and hydroxylation. Without any sacrificial oxidant, we could use the dual catalyst system to produce aniline directly from benzene and ammonia, and phenol from benzene and water, both with evolution of hydrogen gas under unusually mild conditions in excellent yields and selectivities.

  4. Involvement of hydroxyl radicals in the release by ionizing radiation of a cell surface nuclease from Micorcoccus radiodurans

    International Nuclear Information System (INIS)

    Mitchel, R.E.J.

    1975-01-01

    The ionizing radiation-induced release of a surface exonuclease from Micrococcus radiodurans is to a large extent inhibited by the removal of water. Irradiation of a cell suspension saturated with O 2 (an effective aqueous electron and hydrogen atom scavenger) allows the same release as irradiation in the presence of N 2 . Ethanol (a good hydroxyl radical scavenger) protects the enzyme from release. These data suggest that hydroxyl radicals produced by the radiolysis of water are important releasing agents. Hydroxyl radicals produced by the ultraviolet decomposition of H 2 O 2 were effective in releasing the enzyme

  5. Monkey liver cytochrome P450 2C19 is involved in R- and S-warfarin 7-hydroxylation.

    Science.gov (United States)

    Hosoi, Yoshio; Uno, Yasuhiro; Murayama, Norie; Fujino, Hideki; Shukuya, Mitsunori; Iwasaki, Kazuhide; Shimizu, Makiko; Utoh, Masahiro; Yamazaki, Hiroshi

    2012-12-15

    Cynomolgus monkeys are widely used as primate models in preclinical studies. However, some differences are occasionally seen between monkeys and humans in the activities of cytochrome P450 enzymes. R- and S-warfarin are model substrates for stereoselective oxidation in humans. In this current research, the activities of monkey liver microsomes and 14 recombinantly expressed monkey cytochrome P450 enzymes were analyzed with respect to R- and S-warfarin 6- and 7-hydroxylation. Monkey liver microsomes efficiently mediated both R- and S-warfarin 7-hydroxylation, in contrast to human liver microsomes, which preferentially catalyzed S-warfarin 7-hydroxylation. R-Warfarin 7-hydroxylation activities in monkey liver microsomes were not inhibited by α-naphthoflavone or ketoconazole, and were roughly correlated with P450 2C19 levels and flurbiprofen 4-hydroxylation activities in microsomes from 20 monkey livers. In contrast, S-warfarin 7-hydroxylation activities were not correlated with the four marker drug oxidation activities used. Among the 14 recombinantly expressed monkey P450 enzymes tested, P450 2C19 had the highest activities for R- and S-warfarin 7-hydroxylations. Monkey P450 3A4 and 3A5 slowly mediated R- and S-warfarin 6-hydroxylations. Kinetic analysis revealed that monkey P450 2C19 had high V(max) and low K(m) values for R-warfarin 7-hydroxylation, comparable to those for monkey liver microsomes. Monkey P450 2C19 also mediated S-warfarin 7-hydroxylation with V(max) and V(max)/K(m) values comparable to those for recombinant human P450 2C9. R-warfarin could dock favorably into monkey P450 2C19 modeled. These results collectively suggest high activities for monkey liver P450 2C19 toward R- and S-warfarin 6- and 7-hydroxylation in contrast to the saturation kinetics of human P450 2C9-mediated S-warfarin 7-hydroxylation. Copyright © 2012 Elsevier Inc. All rights reserved.

  6. Reactivity of glycyl-amino acids toward hydroxyl radical in neutral aqueous solutions

    International Nuclear Information System (INIS)

    Masuda, Takahiro; Iwashita, Naomi; Shinohara, Hiroyuki; Kondo, Masaharu

    1978-01-01

    Rate constants for reactions of hydroxyl radicals with several glycyl-amino acids were determined by a competition method using p-nitrosodimethylailine as a reference compound. For glycyl-aliphatic amino acids, the enhancement of reactivity was observed as compared with the corresponding free amino acids. The reactivity was explained qualitatively in terms of partial reactivities assigned to each C-H bond of the dipeptides. For glycyl-aromatic amino acids, the rate constants were found to be almost equal to those of the corresponding free amino acids. The reactivity of a protein toward hydroxyl radical was well understood by summation of the rate constants, corrected by steric factors, of amino acid residues located on surface of the protein. The enhanced reactivity of the aliphatic peptides was interpreted in terms of the difference in interaction energy between NH 2 - and NH 3 + -forms of an aliphatic amino acid, which was calculated for the system including glycine and hydroxyl radical according to CNDO/2 method. (auth.)

  7. Preferential hydroxylation over epoxidation catalysis by a horseradish peroxidase mutant: a cytochrome P450 mimic.

    Science.gov (United States)

    de Visser, Sam P

    2007-10-25

    Density functional theory calculations are presented on the catalytic properties of a horseradish peroxidase mutant whereby the axial nitrogen atom is replaced by phosphorus. This mutant has never been studied experimentally and only one theoretical report on this system is known (de Visser, S. P. J. Phys. Chem. B 2006, 110, 20759-20761). Thus, a one-atom substitution in horseradish peroxidase changes the properties of the catalytic center of the enzyme to more cytochrome P450-type qualities. In particular, the phosphorus-substituted horseradish peroxidase mutant reacts with substrates via a unique reactivity pattern, whereby alkanes are regioselectively hydroxylated even in the presence of a double bond. Reaction barriers of propene epoxidation and hydroxylation are almost identical to ones observed for a cytochrome P450 catalyst and significantly higher than those obtained for a horseradish peroxidase catalyst. It is shown that the regioselectivity difference is entropy and thermally driven and that the electron-transfer processes that occur during the reaction mechanism follow cytochrome P450-type patterns in the hydroxylation reaction.

  8. FIH Regulates Cellular Metabolism through Hydroxylation of the Deubiquitinase OTUB1.

    Directory of Open Access Journals (Sweden)

    Carsten C Scholz

    2016-01-01

    Full Text Available The asparagine hydroxylase, factor inhibiting HIF (FIH, confers oxygen-dependence upon the hypoxia-inducible factor (HIF, a master regulator of the cellular adaptive response to hypoxia. Studies investigating whether asparagine hydroxylation is a general regulatory oxygen-dependent modification have identified multiple non-HIF targets for FIH. However, the functional consequences of this outside of the HIF pathway remain unclear. Here, we demonstrate that the deubiquitinase ovarian tumor domain containing ubiquitin aldehyde binding protein 1 (OTUB1 is a substrate for hydroxylation by FIH on N22. Mutation of N22 leads to a profound change in the interaction of OTUB1 with proteins important in cellular metabolism. Furthermore, in cultured cells, overexpression of N22A mutant OTUB1 impairs cellular metabolic processes when compared to wild type. Based on these data, we hypothesize that OTUB1 is a target for functional hydroxylation by FIH. Additionally, we propose that our results provide new insight into the regulation of cellular energy metabolism during hypoxic stress and the potential for targeting hydroxylases for therapeutic benefit.

  9. Modelling On Photogeneration Of Hydroxyl Radical In Surface Waters And Its Reactivity Towards Pharmaceutical Wastes

    International Nuclear Information System (INIS)

    Das, Radha; Vione, Davide; Rubertelli, Francesca; Maurino, Valter; Minero, Claudio; Barbati, Stephane; Chiron, Serge

    2010-01-01

    This paper reports a simple model to describe the formation and reactivity of hydroxyl radicals in the whole column of freshwater lakes. It is based on empirical irradiation data and is a function of the water chemical composition (the photochemically significant parameters NPOC, nitrate, nitrite, carbonate and bicarbonate), the lake conformation best expressed as the average depth, and the water absorption spectrum in a simplified Lambert-Beer approach. The purpose is to derive the lifetime of dissolved molecules, due to reaction with OH, on the basis of their second-order rate constants with the hydroxyl radical. The model was applied to two compounds of pharmaceutical wastes ibuprofen and carbamazepine, for which the second-order rate constants for reaction with the hydroxyl radical were measured by means of the competition kinetics with 2-propanol. The measured values of the rate constants are 1.0x10 10 and 1.6x10 10 M -1 s -1 for ibuprofen and carbamazepine, respectively. The model suggests that the lifetime of a given compound can be very variable in different lakes, even more than the lifetime of different compounds in the same lake. It can be concluded that as far as the reaction with OH, is concerned the concepts of photolability and photostability, traditionally attached to definite compounds, are ecosystem-dependent at least as much as they depend on the molecule under consideration.

  10. Finite element implementation of a thermo-damage-viscoelastic constitutive model for hydroxyl-terminated polybutadiene composite propellant

    Science.gov (United States)

    Xu, Jinsheng; Han, Long; Zheng, Jian; Chen, Xiong; Zhou, Changsheng

    2017-11-01

    A thermo-damage-viscoelastic model for hydroxyl-terminated polybutadiene (HTPB) composite propellant with consideration for the effect of temperature was implemented in ABAQUS. The damage evolution law of the model has the same form as the crack growth equation for viscoelastic materials, and only a single damage variable S is considered. The HTPB propellant was considered as an isotropic material, and the deviatoric and volumetric strain-stress relations are decoupled and described by the bulk and shear relaxation moduli, respectively. The stress update equations were expressed by the principal stresses σ_{ii}R and the rotation tensor M, the Jacobian matrix in the global coordinate system J_{ijkl} was obtained according to the fourth-order tensor transformation rules. Two models having complex stress states were used to verify the accuracy of the constitutive model. The test results showed good agreement with the strain responses of characteristic points measured by a contactless optical deformation test system, which illustrates that the thermo-damage-viscoelastic model perform well at describing the mechanical properties of an HTPB propellant.

  11. Biosynthesis of Tropolones in Streptomyces spp: Interweaving Biosynthesis and Degradation of Phenylacetic Acid and Hydroxylations on Tropone Ring.

    Science.gov (United States)

    Chen, Xuefei; Xu, Min; Lü, Jin; Xu, Jianguo; Wang, Yemin; Lin, Shuangjun; Deng, Zixin; Tao, Meifeng

    2018-04-13

    Tropolonoids are important natural products that contain a unique seven-membered aromatic tropolone core and exhibit remarkable biological activities. 3,7-Dihydroxytropolone (DHT) isolated from Streptomyces species is a multiply hydroxylated tropolone exhibiting antimicrobial, anticancer, and antiviral activities. Herein, we determined the DHT biosynthetic pathway by heterologous expression, gene deletion, and bioconversion. Nine trl genes and some of the aerobic phenylacetic acid degradation pathway genes ( paa ) located outside of the trl biosynthetic gene cluster are required for the heterologous production of DHT. The trlA gene encodes a single-domain protein homologous to the C-terminal enoyl-CoA hydratase domain of PaaZ. TrlA truncates the phenylacetic acid catabolic pathway and redirects it towards the formation of heptacyclic intermediates. TrlB is a 3-deoxy-D-arabino-heptulosonic acid-7-phosphate (DAHP) synthase homolog. TrlH is an unusual bifunctional protein bearing an N-terminal prephenate dehydratase domain and a C-terminal chorismate mutase domain. TrlB and TrlH enhanced de novo biosynthesis of phenylpyruvate, thereby providing abundant precursor for the prolific production of DHT in Streptomyces Six seven-membered carbocyclic compounds were identified from the gene deletion mutants of trlC , trlD , trlE , and trlF Four of these chemicals, including 1,4,6-cycloheptatriene-1-carboxylic acid, tropone, tropolone and 7-hydroxytropolone, were verified as key biosynthetic intermediates. TrlF is required for the conversion of 1,4,6-cycloheptatriene-1-carboxylic acid into tropone. Monooxygenases TrlE and TrlCD catalyze the regioselective hydroxylations of tropone to afford DHT. This study reveals a natural association of anabolism of chorismate and phenylpyruvate, catabolism of phenylacetic acid, and biosynthesis of tropolones in Streptomyces spp. IMPORTANCE Tropolonoids are promising drug lead compounds because of their versatile bioactivities attributed to

  12. Comparative study of Hg(II) adsorption by thiol- and hydroxyl-containing bifunctional montmorillonite and vermiculite

    Energy Technology Data Exchange (ETDEWEB)

    Tran, Lytuong [College of Environment and Energy, South China University of Technology, Guangzhou 510006 (China); The Key Lab of Pollution Control and Ecosystem Restoration in Industry Clusters, Ministry of Education, Guangzhou 510006 (China); QuangBinh University, QuangBinh (Viet Nam); Wu, Pingxiao, E-mail: pppxwu@scut.edu.cn [College of Environment and Energy, South China University of Technology, Guangzhou 510006 (China); The Key Lab of Pollution Control and Ecosystem Restoration in Industry Clusters, Ministry of Education, Guangzhou 510006 (China); The Key Laboratory of Environmental Protection and Eco-Remediation of Guangdong Regular Higher Education Institutions (China); Zhu, Yajie; Liu, Shuai; Zhu, Nengwu [College of Environment and Energy, South China University of Technology, Guangzhou 510006 (China); The Key Lab of Pollution Control and Ecosystem Restoration in Industry Clusters, Ministry of Education, Guangzhou 510006 (China)

    2015-11-30

    Graphical abstract: - Highlights: • Novel adsorbents were prepared by functionalization with BAL to remove Hg(II). • Thiol and hydroxyl groups contributed to the enhancement of Hg(II) removal. • BAL-Vm showed the most adsorption capacity of Hg(II). • The adsorption mechanism was discussed based on the adsorption behaviors. - Abstract: A novel approach to prepare adsorbents for Hg(II) uptake from aqueous media based on the grafting of dimercaprol (BAL), containing thiol and hydroxyl groups, onto the natural montmorillonite and vermiculite was investigated concerning the evaluation of the adsorption capacity. The kinetic study showed that the adsorption process abided by pseudo-second-order model. The adsorption behavior of Hg(II) onto the obtained samples fitted well with Langmuir isotherm model, exhibiting an enhanced maximum adsorption capacity of 8.57 and 3.21 mg g{sup −1} for BAL-Vm and BAL-Mt, respectively. The feasibility of Hg(II) uptake onto the the samples was studied thermodynamically and the calculated coefficients such as ΔH, ΔS and ΔG indicated a physical and spontaneous process. The pH values and coexisting cations had a great influence on Hg(II) removal, confirming the optimal pH value of 4.0–5.0 and the negative correlation between the ionic strength and the adsorption capacity of Hg(II). In general, BAL-Vm possessed a higher efficiency of Hg(II) uptake than BAL-Mt, contrary to that of the pristine clays. The pristine and functionalized materials were investigated by XRD, FTIR, BET, SEM and zeta potential analysis to gain in-depth insight into the structure and surface morphology. The results showed that BAL was successful grafted on montmorillonite and vermiculite surface, providing plentiful adsorption sites as chelating ligands. The mechanisms of Hg(II) adsorption on these samples could be further explained as ion exchange and electrostatic attraction for Vm and Mt, and formation of complexes for BAL-Vm and BAL-Mt.

  13. A novel dihydropyridine with 3-aryl meta-hydroxyl substitution blocks L-type calcium channels in rat cardiomyocytes

    Energy Technology Data Exchange (ETDEWEB)

    Galvis-Pareja, David [Advanced Center for Chronic Diseases (ACCDiS), Facultad de Ciencias Químicas y Farmacéuticas and Facultad Medicina, Universidad de Chile, Santiago (Chile); Centro Estudios Moleculares de la Célula (CEMC), Facultad de Ciencias Químicas y Farmacéuticas and Facultad Medicina, Universidad de Chile, Santiago (Chile); Zapata-Torres, Gerald [Departamento de Química Inorgánica y Analítica, Facultad de Ciencias Químicas y Farmacéuticas, Universidad de Chile, Santiago (Chile); Hidalgo, Jorge [Centro Estudios Moleculares de la Célula (CEMC), Facultad de Ciencias Químicas y Farmacéuticas and Facultad Medicina, Universidad de Chile, Santiago (Chile); Instituto de Ciencias Biomédicas, Facultad de Medicina, Universidad de Chile, Santiago (Chile); Ayala, Pedro [Centro Estudios Moleculares de la Célula (CEMC), Facultad de Ciencias Químicas y Farmacéuticas and Facultad Medicina, Universidad de Chile, Santiago (Chile); and others

    2014-08-15

    Rationale: Dihydropyridines are widely used for the treatment of several cardiac diseases due to their blocking activity on L-type Ca{sup 2+} channels and their renowned antioxidant properties. Methods: We synthesized six novel dihydropyridine molecules and performed docking studies on the binding site of the L-type Ca{sup 2+} channel. We used biochemical techniques on isolated adult rat cardiomyocytes to assess the efficacy of these molecules on their Ca{sup 2+} channel-blocking activity and antioxidant properties. The Ca{sup 2+} channel-blocking activity was evaluated by confocal microscopy on fluo-3AM loaded cardiomyocytes, as well as using patch clamp experiments. Antioxidant properties were evaluated by flow cytometry using the ROS sensitive dye 1,2,3 DHR. Results: Our docking studies show that a novel compound with 3-OH substitution inserts into the active binding site of the L-type Ca{sup 2+} channel previously described for nitrendipine. In biochemical assays, the novel meta-OH group in the aryl in C4 showed a high blocking effect on L-type Ca{sup 2+} channel as opposed to para-substituted compounds. In the tests we performed, none of the molecules showed antioxidant properties. Conclusions: Only substitutions in C2, C3 and C5 of the aryl ring render dihydropyridine compounds with the capacity of blocking LTCC. Based on our docking studies, we postulate that the antioxidant activity requires a larger group than the meta-OH substitution in C2, C3 or C5 of the dihydropyridine ring. - Highlights: • Dihydropyridine (DHP) molecules are widely used in cardiovascular disease. • DHPs block Ca{sup 2+} entry through LTCC—some DHPs have antioxidant activity as well. • We synthesized 6 new DHPs and tested their Ca{sup 2+} blocking and antioxidant activities. • 3-Aryl meta-hydroxyl substitution strongly increases their Ca{sup 2+} blocking activity. • 3-Aryl meta-hydroxyl substitution did not affect the antioxidant properties.

  14. Comparative study of Hg(II) adsorption by thiol- and hydroxyl-containing bifunctional montmorillonite and vermiculite

    International Nuclear Information System (INIS)

    Tran, Lytuong; Wu, Pingxiao; Zhu, Yajie; Liu, Shuai; Zhu, Nengwu

    2015-01-01

    Graphical abstract: - Highlights: • Novel adsorbents were prepared by functionalization with BAL to remove Hg(II). • Thiol and hydroxyl groups contributed to the enhancement of Hg(II) removal. • BAL-Vm showed the most adsorption capacity of Hg(II). • The adsorption mechanism was discussed based on the adsorption behaviors. - Abstract: A novel approach to prepare adsorbents for Hg(II) uptake from aqueous media based on the grafting of dimercaprol (BAL), containing thiol and hydroxyl groups, onto the natural montmorillonite and vermiculite was investigated concerning the evaluation of the adsorption capacity. The kinetic study showed that the adsorption process abided by pseudo-second-order model. The adsorption behavior of Hg(II) onto the obtained samples fitted well with Langmuir isotherm model, exhibiting an enhanced maximum adsorption capacity of 8.57 and 3.21 mg g −1 for BAL-Vm and BAL-Mt, respectively. The feasibility of Hg(II) uptake onto the the samples was studied thermodynamically and the calculated coefficients such as ΔH, ΔS and ΔG indicated a physical and spontaneous process. The pH values and coexisting cations had a great influence on Hg(II) removal, confirming the optimal pH value of 4.0–5.0 and the negative correlation between the ionic strength and the adsorption capacity of Hg(II). In general, BAL-Vm possessed a higher efficiency of Hg(II) uptake than BAL-Mt, contrary to that of the pristine clays. The pristine and functionalized materials were investigated by XRD, FTIR, BET, SEM and zeta potential analysis to gain in-depth insight into the structure and surface morphology. The results showed that BAL was successful grafted on montmorillonite and vermiculite surface, providing plentiful adsorption sites as chelating ligands. The mechanisms of Hg(II) adsorption on these samples could be further explained as ion exchange and electrostatic attraction for Vm and Mt, and formation of complexes for BAL-Vm and BAL-Mt.

  15. Aqueous photochemical degradation of hydroxylated PAHs: Kinetics, pathways, and multivariate effects of main water constituents

    Energy Technology Data Exchange (ETDEWEB)

    Ge, Linke; Na, Guangshui [Key Laboratory for Ecological Environment in Coastal Areas (SOA), National Marine Environmental Monitoring Center, Dalian 116023 (China); Chen, Chang-Er [Lancaster Environment Centre, Lancaster University, Lancaster LA1 4YQ (United Kingdom); Li, Jun [Key Laboratory for Ecological Environment in Coastal Areas (SOA), National Marine Environmental Monitoring Center, Dalian 116023 (China); College of Marine Science, Shanghai Ocean University, Shanghai 201306 (China); Ju, Maowei; Wang, Ying; Li, Kai [Key Laboratory for Ecological Environment in Coastal Areas (SOA), National Marine Environmental Monitoring Center, Dalian 116023 (China); Zhang, Peng, E-mail: pzhang@nmemc.org.cn [Key Laboratory for Ecological Environment in Coastal Areas (SOA), National Marine Environmental Monitoring Center, Dalian 116023 (China); Yao, Ziwei [Key Laboratory for Ecological Environment in Coastal Areas (SOA), National Marine Environmental Monitoring Center, Dalian 116023 (China)

    2016-03-15

    Hydroxylated polycyclic aromatic hydrocarbons (OH-PAHs) are contaminants of emerging concern in the aquatic environment, so it is of great significance to understand their environmental transformation and toxicity. This study investigated the aqueous photochemical behavior of four OH-PAHs, 9-Hydroxyfluorene (9-OHFL), 2-Hydroxyfluorene, 9-Hydroxyphenanthrene and 1-Hydroxypyrene, under simulated sunlight irradiation (λ > 290 nm). It was observed that their photodegradation followed the pseudo-first-order kinetics. Based on the determined quantum yields, their calculated solar apparent photodegradation half-lives in surface waters at 45° N latitude ranged from 0.4 min for 9-Hydroxyphenanthrene to 7.5 × 10{sup 3} min for 9-OHFL, indicating that the OH-PAHs would intrinsically photodegrade fast in sunlit surface waters. Furthermore, 9-OHFL as an example was found to undergo direct photolysis, and self-sensitized photooxidation via ·OH rather than {sup 1}O{sub 2} in pure water. The potential photoreactions involved photoinduced hydroxylation, dehydrogenation and isomerization based on product identification by GC–MS/MS. 9-OHFL photodegraded slower in natural waters than in pure water, which was attributed to the integrative effects of the most photoreactive species, such as Fe(III), NO{sub 3}{sup −}, Cl{sup −} and humic acid. The photomodified toxicity was further examined using Vibrio fischeri, and it was found that the toxicity of photolyzed 9-OHFL did not decrease significantly (p > 0.05) either in pure water or in seawater, implying the comparable or higher toxicity of some intermediates. These results are important for assessing the fate and risks of OH-PAHs in surface waters. - Graphical abstract: Aqueous photochemical behavior of 4 hydroxylated PAHs is first reported on revealing the kinetics, mechanisms, toxicity, and multivariate effects of water constituents. - Highlights: • It is first reported on aqueous photochemical behavior of 4 hydroxylated

  16. Abiraterone Acetate for the Treatment of Chemotherapy-Naïve Metastatic Castration-Resistant Prostate Cancer: An Evidence Review Group Perspective of an NICE Single Technology Appraisal.

    Science.gov (United States)

    Ramaekers, Bram L T; Riemsma, Rob; Tomini, Florian; van Asselt, Thea; Deshpande, Sohan; Duffy, Steven; Armstrong, Nigel; Severens, Johan L; Kleijnen, Jos; Joore, Manuela A

    2017-02-01

    The National Institute for Health and Care Excellence (NICE) invited Janssen, the company manufacturing abiraterone acetate (AA; tradename Zytiga ® ), to submit evidence for the clinical and cost effectiveness of AA in combination with prednisone/prednisolone (AAP) compared with watchful waiting (i.e. best supportive care [BSC]) for chemotherapy-naïve patients with metastatic castration-resistant prostate cancer (mCRPC). Kleijnen Systematic Reviews Ltd (KSR), in collaboration with Maastricht University Medical Center, was commissioned as the Evidence Review Group (ERG). This paper presents a summary of the company submission (CS), the ERG report, subsequent addenda, and the development of the NICE guidance for the use of this drug in England and Wales by the Appraisal Committee (AC). The ERG produced a critical review of the clinical and cost effectiveness of AAP based on the CS. An important question in this appraisal was, according to the ERG, whether AAP followed by docetaxel is more effective than BSC followed by docetaxel. In the COU-AA-302 trial, 239 of 546 (43.8 %) AAP patients and 304 of 542 (56.1 %) BSC patients received docetaxel as subsequent therapy, following AA or placebo. The results for this specific group of patients were not presented in the CS; therefore, the ERG asked the company to provide these data in the clarification letter; however, these data were presented as commercial-in-confidence and cannot therefore be reported here. The ERG's critical assessment of the company's economic evaluation highlighted a number of concerns, including (a) not using the intention-to-treat (ITT) population; (b) inconsistencies in estimating prediction equations; (c) not fully incorporating the impact of adverse events; (d) incorrectly incorporating the new patient access scheme (PAS); and (e) the assumption that AA non-compliance leads to recoverable drug costs. Although some of these issues were adjusted in the ERG base case, the ERG could not estimate

  17. Electron spin resonance of spin-trapped radicals of amines and polyamines. Hydroxyl radical reactions in aqueous solutions and. gamma. radiolysis in the solid state

    Energy Technology Data Exchange (ETDEWEB)

    Mossoba, M.M.; Rosenthal, I.; Riesz, P. (National Cancer Inst., Bethesda, MD (USA))

    1982-06-15

    The reactions of hydroxyl radicals with methylamine, dimethylamine, trimethylamine, diethylamine, sec-butylamine, ethylene-diamine, 1,3-diaminopropane, putrescine, cadaverine, 1,7-diaminoheptane, ornithine, spermidine, spermine, agmatine, and arcaine in aqueous solutions have been investigated by spin-trapping and esr. Hydroxyl radicals were generated by the uv photolysis of H/sub 2/O/sub 2/ and 2-methyl-2-nitrosopropane (MNP) was used as the spin-trap. The effects of ionizing radiation on the same polyamines in the polycrystalline state were also investigated. The free radicals produced by ..gamma..-radiolysis of these solids at room temperature in the absence of air were identified by dissolution in aqueous solutions of MNP. The predominant reaction of OH radicals with amines and polyamines below pH 7 was the abstraction of hydrogen atoms from a carbon that is not adjacent to the protonated amino group. For agmatine and arcaine which contain guanidinium groups abstraction occurred from the ..cap alpha..-CH. Dimethylamine was oxidized to the dimethylnitroxyl radical by H/sub 2/O/sub 2/ in the dark. ..gamma..-Radiolysis of polyamines in the polycrystalline state generated radicals due to H-abstraction from either the ..cap alpha..-Ch or from a carbon atom in the middle of the alkyl chain. The deamination radical was obtained from ornithine.

  18. Proton magnetic resonance studies of 5,6-saturated thymidine derivatives produced by ionizing radiation. Conformational analysis of 6-hydroxylated diastereoisomers

    Energy Technology Data Exchange (ETDEWEB)

    Cadet, J; Ducolomb, R [CEA Centre d' Etudes Nucleaires de Grenoble, 38 (France). Lab. de Radiobiologie; Hruska, F E [Manitoba Univ., Winnipeg (Canada). Dept. of Chemistry

    1979-06-20

    The conformational properties of ten 6-hydroxylated dihydrothymidine derivatives including the various diastereoisomers of 5,6-dihydroxy-5,6-dihydrothymidine, 6-hydroxy-5,6-dihydrothymidine and 5-bromo-6-hydroxy-5,6-dihydrothymidine have been studied by 250 MHz proton magnetic resonance in aqueous solutions. A close correlation has been established between the carbon-6 configuration and the osidic conformation. The increase in the amplitude of the puckering within the furanose ring compared to that of thymidine or 2'-deoxyuridine is more pronounced for the levortatory (6S) nucleosides than for the dextrorotatory (6R) diastereoisomers. The importance of the 2'endo conformer population decreases in the following order: (-)> (+)>thymidine. The absence of destabilizing effects on the g/sup +/ rotameric population about the C(4')-C(5') bond denotes the lack of any interaction between exocyclic hydroxymethyl group and the 6-hydroxyl function or the 2-keto group. The 5,6-saturated nucleosides adopt a preferential anti conformation. The comparison has been extended to syn nucleosides which show opposite trends in the sugar conformation and g/sup +/ distribution.

  19. Combinatorial Alanine Substitution Enables Rapid Optimization of Cytochrome P450BM3 for Selective Hydroxylation of Large Substrates

    KAUST Repository

    Lewis, Jared C.; Mantovani, Simone M.; Fu, Yu; Snow, Christopher D.; Komor, Russell S.; Wong , Chi-Huey; Arnold, Frances H.

    2010-01-01

    Made for each other: Combinatorial alanine substitution of active site residues in a thermostable cytochrome P450BM3 variant was used to generate an enzyme that is active with large substrates. Selective hydroxylation of methoxymethylated

  20. Catalytic ozonation not relying on hydroxyl radical oxidation: A selective and competitive reaction process related to metal-carboxylate complexes

    KAUST Repository

    Zhang, Tao; Croue, Jean-Philippe

    2014-01-01

    Catalytic ozonation following non-hydroxyl radical pathway is an important technique not only to degrade refractory carboxylic-containing organic compounds/matter but also to avoid catalyst deactivation caused by metal-carboxylate complexation

  1. Prolyl hydroxylation regulates protein degradation, synthesis, and splicing in human induced pluripotent stem cell-derived cardiomyocytes.

    Science.gov (United States)

    Stoehr, Andrea; Yang, Yanqin; Patel, Sajni; Evangelista, Alicia M; Aponte, Angel; Wang, Guanghui; Liu, Poching; Boylston, Jennifer; Kloner, Philip H; Lin, Yongshun; Gucek, Marjan; Zhu, Jun; Murphy, Elizabeth

    2016-06-01

    Protein hydroxylases are oxygen- and α-ketoglutarate-dependent enzymes that catalyse hydroxylation of amino acids such as proline, thus linking oxygen and metabolism to enzymatic activity. Prolyl hydroxylation is a dynamic post-translational modification that regulates protein stability and protein-protein interactions; however, the extent of this modification is largely uncharacterized. The goals of this study are to investigate the biological consequences of prolyl hydroxylation and to identify new targets that undergo prolyl hydroxylation in human cardiomyocytes. We used human induced pluripotent stem cell-derived cardiomyocytes in combination with pulse-chase amino acid labelling and proteomics to analyse the effects of prolyl hydroxylation on protein degradation and synthesis. We identified 167 proteins that exhibit differences in degradation with inhibition of prolyl hydroxylation by dimethyloxalylglycine (DMOG); 164 were stabilized. Proteins involved in RNA splicing such as serine/arginine-rich splicing factor 2 (SRSF2) and splicing factor and proline- and glutamine-rich (SFPQ) were stabilized with DMOG. DMOG also decreased protein translation of cytoskeletal and sarcomeric proteins such as α-cardiac actin. We searched the mass spectrometry data for proline hydroxylation and identified 134 high confidence peptides mapping to 78 unique proteins. We identified SRSF2, SFPQ, α-cardiac actin, and cardiac titin as prolyl hydroxylated. We identified 29 prolyl hydroxylated proteins that showed a significant difference in either protein degradation or synthesis. Additionally, we performed next-generation RNA sequencing and showed that the observed decrease in protein synthesis was not due to changes in mRNA levels. Because RNA splicing factors were prolyl hydroxylated, we investigated splicing ± inhibition of prolyl hydroxylation and detected 369 alternative splicing events, with a preponderance of exon skipping. This study provides the first extensive

  2. Biocatalytic hydroxylation of n-butane with in situ cofactor regeneration at low temperature and under normal pressure

    Directory of Open Access Journals (Sweden)

    Svenja Staudt

    2012-02-01

    Full Text Available The hydroxylation of n-alkanes, which proceeds in the presence of a P450-monooxygenase advantageously at temperatures significantly below room temperature, is described. In addition, an enzymatic hydroxylation of the “liquid gas” n-butane with in situ cofactor regeneration, which does not require high-pressure conditions, was developed. The resulting 2-butanol was obtained as the only regioisomer, at a product concentration of 0.16 g/L.

  3. Neurosteroids: Can a 2alpha,3alpha-epoxy ring make up for the 3alpha-hydroxyl group?

    Czech Academy of Sciences Publication Activity Database

    Kasal, Alexander; Buděšínský, Miloš; Mareš, Pavel; Krištofíková, Z.; Leitao, A. J.; Sá e Melo, M. L.; Silva, M. M. C.

    2016-01-01

    Roč. 105, Jan (2016), s. 12-18 ISSN 0039-128X R&D Projects: GA ČR(CZ) GA305/09/0846; GA ČR(CZ) GBP304/12/G069 Institutional support: RVO:61388963 ; RVO:67985823 Keywords : neurosteroids * NMR spectrometry * GABA(A) receptor * TBPS-test Subject RIV: CC - Organic Chemistry; FH - Neurology (FGU-C) Impact factor: 2.282, year: 2016

  4. Preparation of gold nanoparticles in the presence of citric acid-based dendrimers containing periphery hydroxyl groups

    International Nuclear Information System (INIS)

    Namazi, Hassan; Fard, Ahmad Mohammad Pour

    2011-01-01

    Highlights: → The most advantage of citric acid-based dendrimers is their novelty from monomeric point of view and their simple preparation method. → The size and also size distribution of Au nanoparticles can be controlled through the choice of the dendrimer generation. → Here, we report the preparation of the stable, isolated and uniform Au nanoparticles with using a simple method in water media.→ It was observed that the size of Au nanoparticles is increased with increasing the generation of dendrimer. - Abstract: In this work, Au nanoparticles were produced with reduction of HAuCl 4 using NaBH 4 in the presence of different generations of citric acid-based dendrimers. The greater water solubility of the newly prepared dendrimers motivated us for the preparation of Au nanoparticles in water media. Therefore, the stable, isolated and uniform type Au nanoparticles were prepared through simple process in water. UV-Vis absorption, high-resolution transmission electronic microscopy (HRTEM), electron diffraction (ED) and energy dispersive X-ray (EDX) methods were used to investigate the morphology and structure determination of the obtained gold nanoparticles.

  5. A single-blind study of the efficacy and safety of intravenous granisetron compared with alizapride plus dexamethasone in the prophylaxis and control of emesis in patients receiving 5-day cytostatic therapy. The Granisetron Study Group.

    Science.gov (United States)

    Bremer, K

    1992-01-01

    200 cancer patients who were due to receive fractionated chemotherapy (cisplatin greater than or equal to 15, ifosfamide greater than or equal to 1.2 or etoposide greater than or equal to 120, all mg/m2 per day) for 5 days, entered a multicentre study. Patients were randomised single-blind to receive either prophylactic intravenous granisetron (40 micrograms/kg) or alizapride (4 mg/kg followed by 4 mg/kg at 4 and 8 h post-treatment) plus dexamethasone 8 mg. Granistron was superior to the combination in preventing nausea and vomiting (54% vs. 43% complete responders). The differences were in the cisplatin-treated group. The time to first episode of moderate to severe nausea was significantly longer in the granisetron group (P = 0.03). Dosing with granisetron was more simple, with over 85% of patients requiring only a single prophylactic dose. Fewer patients receiving granisetron experienced adverse events (48% vs. 62%, P = 0.047). The frequency of constipation was, as expected, significantly higher in the granisetron group. Extrapyramidal effects, which were not noted by any granisetron patient, occurred in 5.3% of comparator patients.

  6. New fluorescent probes of the hydroxyl radical: characterisation and modelization of the reactivity of coumarin derivatives with HO

    International Nuclear Information System (INIS)

    Louit, G.

    2005-10-01

    The hydroxyl radical is involved in a wide range of different fields, from oxidative stress to atmospheric chemistry. In addition to the study of oxidative damage in biological media, the hydroxyl radical detection allows to perform a dosimetry when it is produced by ionising radiation. The aims of this work have been double: - to improve the detection of the hydroxyl radical by the design of new probes - to improve knowledge on the reactive pathways in which the hydroxyl radical is involved. We have studied the coumarin molecule, as well as 6 derivatives that we have synthesised, as fluorescent probes of the hydroxyl radical. Firstly, fluorescence spectroscopy and HPLC chromatography have allowed the evaluation of the sensibility and selectivity of detection of the probes. Consequently to this study, two applications have been developed, concerning the determination of rate constants by competition kinetics and bidimensional dosimetry. Secondly, we have studied the reactivity of the hydroxyl radical through the regioselectivity of its addition on the aromatic cycle. This problem was addressed by the combined use of experimental methods such as time resolved kinetics and HPLC along with interpretation from classical and ab initio modelization. (author)

  7. Short- and long-term performance of a tripolar down-sized single lead for implantable cardioverter defibrillator treatment: a randomized prospective European multicenter study. European Endotak DSP Investigator Group.

    Science.gov (United States)

    Sandstedt, B; Kennergren, C; Schaumann, A; Herse, B; Neuzner, J

    1998-11-01

    A new, thinner (10 Fr) and more flexible, single-pass transvenous endocardial ICD lead, Endotak DSP, was compared with a conventional lead, Endotak C, as a control in a prospective randomized multicenter study in combination with a nonactive can ICD. A total of 123 patients were enrolled, 55 of whom received a down-sized DSP lead. Lead-alone configuration was successfully implanted in 95% of the DSP patients vs 88% in the control group. The mean defibrillation threshold (DFT) was determined by means of a step-down protocol, and was identical in the two groups, 10.5 +/- 4.8 J in the DSP group versus 10.5 +/- 4.8 J in the control group. At implantation, the DSP mean pacing threshold was lower, 0.51 +/- 0.18 V versus 0.62 +/- 0.35 V (p < 0.05) in the control group, and the mean pacing impedance higher, 594 +/- 110 omega vs 523 +/- 135 omega (p < 0.05). During the follow-up period, the statistically significant difference in thresholds disappeared, while the difference in impedance remained. Tachyarrhythmia treatment by shock or antitachycardia pacing (ATP) was delivered in 53% and 41%, respectively, of the patients with a 100% success rate. In the DSP group, all 28 episodes of polymorphic ventricular tachycardia or ventricular fibrillation were converted by the first shock as compared to 57 of 69 episodes (83%) in the control group (p < 0.05). Monomorphic ventricular tachycardias were terminated by ATP alone in 96% versus 94%. Lead related problems were minor and observed in 5% and 7%, respectively. In summary, both leads were safe and efficacious in the detection and treatment of ventricular tachyarrhythmias. There were no differences between the DSP and control groups regarding short- or long-term lead related complications.

  8. Improved brain MRI indices in the acute brain stem infarct sites treated with hydroxyl radical scavengers, Edaravone and hydrogen, as compared to Edaravone alone. A non-controlled study

    Directory of Open Access Journals (Sweden)

    Ono Hirohisa

    2011-06-01

    Full Text Available Abstract Background In acute stage of cerebral infarction, MRI indices (rDWI & rADC deteriorate during the first 3-7 days after the ictus and then gradually normalize in approximately 10 days (pseudonormalization time, although the tissue is already infarcted. Since effective treatments improve these indices significantly and in less than the natural pseudonormalization time, a combined analysis of these changes provides an opportunity for objective evaluation on the effectiveness of various treatments for cerebral infarction. Hydroxyl radicals are highly destructive to the tissue and aggravate cerebral infarction. We treated brainstem infarction patients in acute stage with hydroxyl radical scavengers (Edaravone and hydrogen by intravenous administration and evaluated the effects of the treatment by a serial observation and analysis of these MRI indices. The effects of the treatment were evaluated and compared in two groups, an Edaravone alone group and a combined group with Edaravone and hydrogen, in order to assess beneficial effects of addition of hydrogen. Methods The patients were divided in Edaravone only group (E group. 26 patients and combined treatment group with Edaravone and hydrogen enriched saline (EH group. 8 patients. The extent of the initial hump of rDWI, the initial dip of rADC and pseudo-normalization time were determined in each patient serially and averages of these data were compared in these two groups and also with the natural course in the literatures. Results The initial hump of rDWI reached 2.0 in the E group which was better than 2.5 of the natural course but was not as good as 1.5 of the EH group. The initial dip of rADC was 0.6 in the E group which was close to the natural course but worse than 0.8 of the EH group. Pseudonormalization time of rDWI and rADC was 9 days only in EH group but longer in other groups. Addition of hydrogen caused no side effects. Conclusions Administration of hydroxyl radical scavengers in

  9. An ex vivo, assessor blind, randomised, parallel group, comparative efficacy trial of the ovicidal activity of three pediculicides after a single application - melaleuca oil and lavender oil, eucalyptus oil and lemon tea tree oil, and a "suffocation" pediculicide

    Directory of Open Access Journals (Sweden)

    Altman Phillip M

    2011-08-01

    Full Text Available Abstract Background There are two components to the clinical efficacy of pediculicides: (i efficacy against the crawling-stages (lousicidal efficacy; and (ii efficacy against the eggs (ovicidal efficacy. Lousicidal efficacy and ovicidal efficacy are confounded in clinical trials. Here we report on a trial that was specially designed to rank the clinical ovicidal efficacy of pediculicides. Eggs were collected, pre-treatment and post-treatment, from subjects with different types of hair, different coloured hair and hair of different length. Method Subjects with at least 20 live eggs of Pediculus capitis (head lice were randomised to one of three treatment-groups: a melaleuca oil (commonly called tea tree oil and lavender oil pediculicide (TTO/LO; a eucalyptus oil and lemon tea tree oil pediculicide (EO/LTTO; or a "suffocation" pediculicide. Pre-treatment: 10 to 22 live eggs were taken from the head by cutting the single hair with the live egg attached, before the treatment (total of 1,062 eggs. Treatment: The subjects then received a single treatment of one of the three pediculicides, according to the manufacturers' instructions. Post-treatment: 10 to 41 treated live eggs were taken from the head by cutting the single hair with the egg attached (total of 1,183 eggs. Eggs were incubated for 14 days. The proportion of eggs that had hatched after 14 days in the pre-treatment group was compared with the proportion of eggs that hatched in the post-treatment group. The primary outcome measure was % ovicidal efficacy for each of the three pediculicides. Results 722 subjects were examined for the presence of eggs of head lice. 92 of these subjects were recruited and randomly assigned to: the "suffocation" pediculicide (n = 31; the melaleuca oil and lavender oil pediculicide (n = 31; and the eucalyptus oil and lemon tea tree oil pediculicide (n = 30 subjects. The group treated with eucalyptus oil and lemon tea tree oil had an ovicidal efficacy of 3.3% (SD

  10. The hydroxylation of passive oxide films on X-70 steel by dissolved hydrogen studied by nuclear reaction analysis, Auger electron spectroscopy, X-ray photoelectron spectroscopy and secondary ion mass spectroscopy

    International Nuclear Information System (INIS)

    Zhang Chunsi; Luo Jingli; Munoz-Paniagua, David; Norton, Peter R.

    2006-01-01

    Dissolved hydrogen is known to reduce the corrosion resistance of a passive oxide film on iron and its alloys, especially towards pitting corrosion. Electrochemical techniques have been used to show that the passive films are changed by dissolved hydrogen in an alloy substrate, but direct confirmation of the chemical and compositional profiles and changes has been missing. In this paper we report the direct profiling and compositional analysis of the 4 nm passive film on X-70 steel by Auger electron spectroscopy (AES), secondary ion mass spectrometry (SIMS), X-ray photoelectron spectroscopy (XPS) and nuclear reaction analysis (NRA) while hydrogen (deuterium) is charged into the alloy samples from the reverse, unpassivated side. The only route for D to the passive film is therefore by dissolution and diffusion. We show that the original duplex structure of the passive film is converted to a more continuous film containing hydroxyl groups, by reaction with the dissolved hydrogen. This conversion of the oxide ions to hydroxyl groups can lead to more rapid reaction and replacement with (e.g.) Cl - , which is known to enhance pitting. These results are entirely consistent with previous electrochemical studies and provide the first direct confirmation of models on the formation and role of hydroxyl groups derived from these earlier studies

  11. Oxidation of Peptides by Methyl(trifluoromethyl)dioxirane: the Protecting Group Matters

    Science.gov (United States)

    Rella, Maria Rosaria; Williard, Paul G.

    2011-01-01

    Representative Boc protected and acetyl protected peptide methyl esters bearing alkyl side chains undergo effective oxidation using methyl(trifluoromethyl)dioxirane (1b) under mild conditions. We observe a protecting group dependency in the chemoselectivity displayed by the dioxirane 1b. N-hydroxylation occurs in the case of the Boc protected peptides, side chain hydroxylation takes place in the case of acetyl protected peptides. Both are attractive transformations since they yield derivatized peptides that serve as valuable synthons. PMID:17221970

  12. Catalytic ozonation not relying on hydroxyl radical oxidation: A selective and competitive reaction process related to metal-carboxylate complexes

    KAUST Repository

    Zhang, Tao

    2014-01-01

    Catalytic ozonation following non-hydroxyl radical pathway is an important technique not only to degrade refractory carboxylic-containing organic compounds/matter but also to avoid catalyst deactivation caused by metal-carboxylate complexation. It is unknown whether this process is effective for all carboxylates or selective to special molecule structures. In this work, the selectivity was confirmed using O3/(CuO/CeO2) and six distinct ozone-resistant probe carboxylates (i.e., acetate, citrate, malonate, oxalate, pyruvate and succinate). Among these probe compounds, pyruvate, oxalate, and citrate were readily degraded following the rate order of oxalate>citrate>pyruvate, while the degradation of acetate, malonate, and succinate was not promoted. The selectivity was independent on carboxylate group number of the probe compounds and solution pH. Competitive degradation was observed for carboxylate mixtures following the preference order of citrate, oxalate, and finally pyruvate. The competitive degradation was ascribed to competitive adsorption on the catalyst surface. It was revealed that the catalytically degradable compounds formed bidentate chelating or bridging complexes with surface copper sites of the catalyst, i.e., the active sites. The catalytically undegradable carboxylates formed monodentate complexes with surface copper sites or just electrostatically adsorbed on the catalyst surface. The selectivity, relying on the structure of surface metal-carboxylate complex, should be considered in the design of catalytic ozonation process. © 2013 Elsevier B.V.

  13. Hydroxyl-radical-induced oxidation of cyclic dipeptides: Reactions of free peptide radicals and their peroxyl radicals

    International Nuclear Information System (INIS)

    Mieden, O.J.

    1989-01-01

    In the course of this study investigations were carried out into the reactions of hydroxyl radicals and hydrogen atoms with cyclic dipeptides as well as the subsequent reactions of peptide radicals and their peroxyl radicals in aqueous solution. The radiolysis products formed in the absence and presence of oxygen or transient metal complexes were characterized and determined on a quantitative basis. The linking of information from product analyses to the kinetic data for transient species obtained by time-resolving UV/VIS and conductivity measurements (pulse radiolysis) as well as computer-assisted simulations of individual events during the reaction permitted an evaluation of the mechanisms underlying the various processes and an identification of interim products with short life-times, which did or did not belong to the group of radicals. Through the characterization of key reactions of radicals and peroxyl radicals of this substance class a major advance has been made towards a better understanding of the role of radicals in the peptide compound and the mechanisms involved in indirect radiation effects on long-chain peptides and proteins. (orig.) [de

  14. Reduced graphene oxide/hydroxylated styrene-butadiene-styrene tri-block copolymer electroconductive nanocomposites: Preparation and properties

    Energy Technology Data Exchange (ETDEWEB)

    Xiong, Yuanqin; Xie, Yanyan [Institute of Polymer Science and Engineering, College of Chemistry and Chemical Engineering, Hunan University, Changsha 410082 (China); Zhang, Fan [College of Chemistry and Chemical Engineering, Jishou University, Jishou 416000 (China); Ou, Encai; Jiang, Zhuojuan; Ke, Lili; Hu, Ding [Institute of Polymer Science and Engineering, College of Chemistry and Chemical Engineering, Hunan University, Changsha 410082 (China); Xu, Weijian, E-mail: weijianxu59@gmail.com [Institute of Polymer Science and Engineering, College of Chemistry and Chemical Engineering, Hunan University, Changsha 410082 (China)

    2012-08-20

    Highlights: Black-Right-Pointing-Pointer RGO/HO-SBS nanocomposites are prepared successfully. Black-Right-Pointing-Pointer The introduction of -OH improves the compatibility between RGO and HO-SBS. Black-Right-Pointing-Pointer RGO disperse homogeneously and form a compact continuous network in matrix (HO-SBS). Black-Right-Pointing-Pointer The percolation threshold of the nanocomposites is of 0.2-0.5 wt% (0.09-0.23 vol%) and its conductivity is up to 1.3 S/m. - Abstract: Flexible and electroconductive nanocomposites based on reduced graphene oxide (RGO) and hydroxylated styrene-butadiene-styrene tri-block copolymer (HO-SBS) were prepared by solution blending method. By the introduction of the groups of -OH and >C=O onto SBS, the compatibility between RGO and SBS was enhanced. Field emission scanning electron microscopy (FE-SEM) and high-resolution transmission electron microscopy (HR-TEM) showed that RGO dispersed homogeneously and formed a compact continuous network in matrix (HO-SBS). The addition of RGO improved the thermal stability of the RGO/HO-SBS nanocomposites while slightly lowered the mechanical property. Moreover, RGO gave the nanocomposites a maximum electrical conductivity up to 1.3 S/m.

  15. A Masing Event in NGC 6334I: Contemporaneous Flaring of Hydroxyl, Methanol and Water Masers

    Science.gov (United States)

    MacLeod, G. C.; Smits, D. P.; Goedhart, S.; Hunter, T. R.; Brogan, C. L.; Chibueze, J. O.; van den Heever, S. P.; Thesner, C. J.; Banda, P. J.; Paulsen, J. D.

    2018-04-01

    As a product of the maser monitoring program with the 26 m telescope of the Hartebeesthoek Radio Astronomy Observatory (HartRAO), we present an unprecedented, contemporaneous flaring event of 10 maser transitions in hydroxyl, methanol, and water that began in 2015 January in the massive star-forming region NGC 6334I in the velocity range -10 to -2 km s-1. The 6.7 GHz methanol and 22.2 GHz water masers began flaring within 22 days of each other, while the 12.2 GHz methanol and 1665 MHz hydroxyl masers flared 80 and 113 days later respectively. The 1665 MHz, 6.7 GHz, and 22.2 GHz masers have all remained in their flared state for nearly 3 years. The brightest flaring components increased by factors of 66, 21, 26, and 20 in the 12.2 and 6.7 GHz methanol, 1665 MHz hydroxyl and 22.2 GHz water maser transitions respectively; some weaker components increased by up to a factor of 145. We also report new maser emission in the 1720, 6031, and 6035 MHz OH lines and the 23.1 GHz methanol line, along with the detection of only the fifth 4660 MHz OH maser. We note the correlation of this event with the extraordinary (sub)millimeter continuum outburst from the massive protostellar system NGC 6334I-MM1 and discuss the implications of the observed time lags between different maser velocity components on the nature of the outburst. Finally, we identify two earlier epoch maser flaring events likely associated with this object, which suggest a recurring accretive phenomenon that generates powerful radiative outbursts.

  16. Levofloxacin oxidation by ozone and hydroxyl radicals: kinetic study, transformation products and toxicity.

    Science.gov (United States)

    Hamdi El Najjar, Nasma; Touffet, Arnaud; Deborde, Marie; Journel, Romain; Leitner, Nathalie Karpel Vel

    2013-10-01

    This work was carried out to investigate the fate of the antibiotic levofloxacin upon oxidation with ozone and hydroxyl radicals. A kinetic study was conducted at 20 °C for each oxidant. Ozonation experiments were performed using a competitive kinetic method with carbamazepin as competitor. Significant levofloxacin removal was observed during ozonation and a rate constant value of 6.0×10(4) M(-1) s(-1) was obtained at pH 7.2. An H2O2/UV system was used for the formation of hydroxyl radicals HO. The rate constant of HO was determined in the presence of a high H2O2 concentration. The kinetic expressions yielded a [Formula: see text] value of 4.5×10(9) M(-1) s(-1) at pH 6.0 and 5.2×10(9) M(-1) s(-1) at pH 7.2. These results were used to develop a model to predict the efficacy of the ozonation process and pharmaceutical removal was estimated under different ozonation conditions (i.e. oxidant concentrations and contact times). The results showed that levofloxacin was completely degraded by molecular ozone during ozonation of water and that hydroxyl radicals had no effect in real waters conditions. Moreover, LC/MS/MS and toxicity assays using Lumistox test were performed to identify ozonation transformation products. Under these conditions, four transformation products were observed and their chemical structures were proposed. The results showed an increase in toxicity during ozonation, even after degradation of all of the observed transformation products. The formation of other transformation products not identified under our experimental conditions could be responsible for the observed toxicity. These products might be ozone-resistant and more toxic to Vibrio fisheri than levofloxacin. Copyright © 2013 Elsevier Ltd. All rights reserved.

  17. Catalytic oxidation of 2-aminophenols and ortho hydroxylation of aromatic amines by tyrosinase

    International Nuclear Information System (INIS)

    Toussaint, O.; Lerch, K.

    1987-01-01

    The usual substrates of tyrosinase, a copper-containing monooxygenase (EC 1.14.18.1), are monophenols and o-diphenols which are both converted to o-quinones. In this paper, the authors studied the reaction of this enzyme with two new classes of substrates: aromatic amines and o-aminophenols, structural analogues of monophenols and o-diphenols, respectively. They undergo the same catalytic reactions (ortho hydroxylation and oxidation), as documented by product analysis and kinetic studies. In the presence of tyrosinase, arylamines and o-aminophenols are converted to o-quinone imines, which are isolated as quinone anils or phenoxazones. As an example, in the presence of tyrosinase, 2-amino-3-hydroxybenzoic acid (an o-aminophenol) is converted to cinnabarinic acid, a well-known phenoxazone, while p-aminotoluene (an aromatic amine) gives rise to the formation of 5-amino-2-methyl-1,4-benzoquinone 1-(4-methylanil). Kinetic studies using an oxygen electrode show that arylamines and the corresponding monophenols exhibit similar Michaelis constants. In contrast, the reaction rates observed for aromatic amines are relatively slow as compared to monophenols. The enzymatic conversion of arylamines by tryosinase is different from the typical ones: N-oxidation and ring hydroxylation without further oxidation. This difference originates from the regiospecific hydroxylation (ortho position) and subsequent oxidation of the intermediate o-aminophenol to the corresponding o-quinone imine. Finally, the well-know monooxygenase activity of tyrosinase was also confirmed for the aromatic amine p-aminotoluene, with 18 O 2

  18. Spectral characterization of superficial coal groups

    International Nuclear Information System (INIS)

    Ahmad, I.; Khan, M.A.; Ishaq, M.; Shakirullah; Bahadur, A.

    2004-01-01

    Spectral characterization of superficial coal groups was performed in KBr pellets. KBr Pellets were prepared for virgin and variously pretreated coal samples. Spectra of satisfactory resolution were obtained in wave number range-4000-400 cm /sup -1/. Presence of broad absorption bands corresponds to hydroxyl, carbonyl, carboxyl and phenolic functionalities in the spectra clearly define their presence in all samples understudy. Forced oxidation proved effective for oxidation of both aliphatic and aromatic configurations, which can be revealed from the respective spectra. (author)

  19. Improving anxiety regulation in patients with breast cancer at the beginning of the survivorship period: a randomized clinical trial comparing the benefits of single-component and multiple-component group interventions.

    Science.gov (United States)

    Merckaert, Isabelle; Lewis, Florence; Delevallez, France; Herman, Sophie; Caillier, Marie; Delvaux, Nicole; Libert, Yves; Liénard, Aurore; Nogaret, Jean-Marie; Ogez, David; Scalliet, Pierre; Slachmuylder, Jean-Louis; Van Houtte, Paul; Razavi, Darius

    2017-08-01

    To compare in a multicenter randomized controlled trial the benefits in terms of anxiety regulation of a 15-session single-component group intervention (SGI) based on support with those of a 15-session multiple-component structured manualized group intervention (MGI) combining support with cognitive-behavioral and hypnosis components. Patients with nonmetastatic breast cancer were randomly assigned at the beginning of the survivorship period to the SGI (n = 83) or MGI (n = 87). Anxiety regulation was assessed, before and after group interventions, through an anxiety regulation task designed to assess their ability to regulate anxiety psychologically (anxiety levels) and physiologically (heart rates). Questionnaires were used to assess psychological distress, everyday anxiety regulation, and fear of recurrence. Group allocation was computer generated and concealed till baseline completion. Compared with patients in the SGI group (n = 77), patients attending the MGI group (n = 82) showed significantly reduced anxiety after a self-relaxation exercise (P = .006) and after exposure to anxiety triggers (P = .013) and reduced heart rates at different time points throughout the task (P = .001 to P = .047). The MGI participants also reported better everyday anxiety regulation (P = .005), greater use of fear of recurrence-related coping strategies (P = .022), and greater reduction in fear of recurrence-related psychological distress (P = .017) compared with the SGI group. This study shows that an MGI combining support with cognitive-behavioral techniques and hypnosis is more effective than an SGI based only on support in improving anxiety regulation in patients with breast cancer. Copyright © 2016 John Wiley & Sons, Ltd.

  20. Reaction of hydroxyl radicals with ammonia in liquid water at elevated temperatures

    DEFF Research Database (Denmark)

    Hickel, B.; Sehested, K.

    1992-01-01

    The reaction of hydroxyl radical with ammonia in aqueous solutions has been studied by pulse radiolysis in the temperature range 20-200-degrees-C. The rate constant of the reaction was determined by monitoring the decay of the OH radical absorption at 260 nm for different concentrations of ammonia....... At room temperature the rate constant is (9.7 +/- 1) x 10(7) dm3 mol-1 s-1. In the whole range of temperatures the Tate constant follows Arrhenius law with an activation energy of (5.7 +/- 1) kJ mol-1. The protective effect of dissolved hydrogen on the radiolytic decomposition of ammon a is discussed....

  1. Investigating the Source of Water and/or Hydroxyl on Asteroid (16) Psyche

    Science.gov (United States)

    Takir, D.; Reddy, V.; Sanchez, J. A.; Shepard, M. K.; Emery, J. P.

    2017-12-01

    Asteroid (16) Psyche will be visited by the Psyche mission, which was selected by NASA and will be launched in 2022 as the 14th Discovery mission. Psyche is thought to be one of the most massive exposed metallic core in the asteroid belt. The high radar albedos, thermal inertia, and density of Psyche revealed that this asteroid is composed of almost entirely of Fe-Ni metal. Psyche is also characterized by moderately red spectra and the presence of weak features (attributed to silicates) in the visible and near-infrared (NIR) region (0.3-2.5 µm). Recent NIR observations also showed rotational spectral variations indicating a possible change in the metal/silicate ratio on the surface of this asteroid. Additionally, we observed Psyche in the 3-µm spectral region using the long-wavelength cross-dispersed (LXD: 1.9-4.2 µm) mode of the SpeX spectrograph/imager at the NASA Infrared Telescope Facility (IRTF). Our observations revealed that Psyche exhibits a 3-µm feature, more likely attributed to water- and/or hydroxyl molecules. While the source of water and/or hydroxyl on Psyche remains unclear, we proposed a few possible mechanisms for their formation: (1) the water/hydroxyl-rich materials detected on Psyche might have been delivered to its surface by carbonaceous impactors (like on Vesta), (2) Psyche may not be entirely exposed metallic, instead, its surface has a core-mantle boundary of a differentiated body that was disrupted by impacts (e.g., Pallasite-like), or (3) the water/hydroxyl-rich materials detected on Psyche is produced by Solar wind implantation (like on the Moon). In this talk we will discuss these three possible mechanisms and hypotheses and how they can be tested prior to the launch of the Psyche spacecraft using predictive laboratory measurements and modeling, and during the spacecraft encounter with the asteroid using the mission main instruments that will include the multispectral imagers, the gamma-ray and neutron spectrometer, and the dual

  2. Positron annihilation analysis of epoxy/hydroxyl terminated butyl nitrile rubber (EP/HTBN) system

    International Nuclear Information System (INIS)

    Zeng Minfeng; Chen Ning; Ji Genzhong; Sun Xudong; Zhao Rener; Xiao Huiquan; Qi Chenze; Wang Baoyi

    2007-01-01

    The free volume properties of epoxy/hydroxyl terminated butyl nitrile rubber (EP/HTBN) have been studied by means of positron annihilation technique. The toughness effect is found to be correlated with the content of HTBN and the free volume properties of the EP/HTBN interfaces. When the content of HTBN component is 5%, the free volume size in the interface is close to that of EP, and the toughness effect is strong. But with further addition of HTBN, holes with big size free volume are formed in the interface, and the toughness effect is limited. (authors)

  3. Kinetics and mechanism of the reaction of recombination of vinyl and hydroxyl radicals

    Science.gov (United States)

    Knyazev, Vadim D.

    2017-10-01

    The recombination of the vinyl (C2H3) and the hydroxyl (OH) radicals was studied computationally using quantum chemistry and master equation/RRKM. The reaction mechanism includes the initial addition, several isomerization steps, and decomposition via seven different channels. The spectrum of products demonstrates temperature dependence in the 300-3000 K range. At low temperatures (below 1600 K), CH3 + HCO products are dominant but at elevated temperatures vinoxy radical (CH2CHO) and hydrogen atom become more important. The acetyl (CH3CO) + H products and formation of vinylidene (CH2C:) and water products are minor but non-negligible.

  4. Pulsed corona discharge: the role of ozone and hydroxyl radical in aqueous pollutants oxidation.

    Science.gov (United States)

    Preis, S; Panorel, I C; Kornev, I; Hatakka, H; Kallas, J

    2013-01-01

    Ozone and hydroxyl radical are the most active oxidizing species in water treated with gas-phase pulsed corona discharge (PCD). The ratio of the species dependent on the gas phase composition and treated water contact surface was the objective for the experimental research undertaken for aqueous phenol (fast reaction) and oxalic acid (slow reaction) solutions. The experiments were carried out in the reactor, where aqueous solutions showered between electrodes were treated with 100-ns pulses of 20 kV voltage and 400 A current amplitude. The role of ozone increased with increasing oxygen concentration and the oxidation reaction rate. The PCD treatment showed energy efficiency surpassing that of conventional ozonation.

  5. Inducible hydroxylation and demethylation of the herbicide isoproturon by Cunninghamella elegans.

    Science.gov (United States)

    Hangler, Martin; Jensen, Bo; Rønhede, Stig; Sørensen, Sebastian R

    2007-03-01

    A screening of 27 fungal strains for degradation of the phenylurea herbicide isoproturon was performed and yielded 15 strains capable of converting the herbicide to polar metabolites. The zygomycete fungus Cunninghamella elegans strain JS/2 isolated from an agricultural soil converted isoproturon to several known hydroxylated metabolites. In addition, unknown metabolites were produced in minor amounts. Inducible degradation was indicated by comparing resting cells pregrown with or without isoproturon. This shows that strain JS/2 is capable of partially degrading isoproturon and that one or more of the enzymes involved are inducible upon isoproturon exposure.

  6. A consistent set of thermodynamic constants for americium (III) species with hydroxyl and carbonate

    International Nuclear Information System (INIS)

    Kerrisk, J.F.; Silva, R.J.

    1986-01-01

    A consistent set of thermodynamic constants for aqueous species, and compounds of Am(III) with hydroxyl and carbonate ligands has been developed. The procedure used to develop these constants involved establishing a value for one formation constant at a time in a sequential order, starting with the hydrolysis products and hydroxide solids, and then proceeding to carbonate species. The EQ3NR chemical-equilibrium model was used to test the constants developed. These constants are consistent with most of the experimental data that form their basis; however, considerable uncertainty still exists in some aspects of the Am(III) data

  7. One- or two-electron water oxidation, hydroxyl radical, or H_2O_2 evolution

    International Nuclear Information System (INIS)

    Siahrostami, Samira; Li, Guo-Ling; Viswanathan, Venkatasubramanian; Nørskov, Jens K.

    2017-01-01

    Electrochemical or photoelectrochemcial oxidation of water to form hydrogen peroxide (H_2O_2) or hydroxyl radicals (•OH) offers a very attractive route to water disinfection, and the first process could be the basis for a clean way to produce hydrogen peroxide. A major obstacle in the development of effective catalysts for these reactions is that the electrocatalyst must suppress the thermodynamically favored four-electron pathway leading to O_2 evolution. Here, we develop a thermochemical picture of the catalyst properties that determine selectivity toward the one, two, and four electron processes leading to •OH, H_2O_2, and O_2.

  8. Facile Synthesis of a Hydroxyl-Functionalized Tröger’s Base Diamine: A New Building Block for High-Performance Polyimide Gas Separation Membranes

    KAUST Repository

    Ma, Xiaohua

    2017-12-04

    Two intrinsically microporous polyimides (PIM-PIs) were synthesized by the polycondensation reaction of 4,4′-(hexafluoroisopropylidene)diphthalic anhydride (6FDA) and 3,3,3′,3′-tetramethylspirobisindane-6,7,6′,7′-tetracarboxylic dianhydride (SBI) with a newly designed o-hydroxyl-functionalized Tröger’s base diamine, 1,7-diamino-6H,12H-5,11-methanodibenzo[1,5]diazocine-2,8-diol (HTB). Both amorphous PIM-PIs were soluble in aprotic solvents and showed excellent thermal stability with onset decomposition temperature of ∼380 °C. SBI-HTB displayed a higher CO2 permeability (466 vs 67 barrer) than 6FDA-HTB but a significantly lower selectivity for CO2/CH4 (29 vs 73), H2/CH4 (29 vs 181), O2/N2 (4.6 vs 6.0), and N2/CH4 (1 vs 2.5). 6FDA-HTB displayed the highest gas-pair permselectivity values of all reported OH-functionalized PIM-PIs to date. The high permselectivity of 6FDA-HTB resulted primarily from exceptional diffusion selectivity due to strong size-sieving properties caused by hydrogen bonding between the proton of the hydroxyl group and the nitrogen atoms in the tertiary amine of the Tröger’s base (O–H···N).

  9. Reaction Mechanisms and Structural and Physicochemical Properties of Caffeic Acid Grafted Chitosan Synthesized in Ascorbic Acid and Hydroxyl Peroxide Redox System.

    Science.gov (United States)

    Liu, Jun; Pu, Huimin; Chen, Chong; Liu, Yunpeng; Bai, Ruyu; Kan, Juan; Jin, Changhai

    2018-01-10

    The ascorbic acid (AA) and hydroxyl peroxide (H 2 O 2 ) redox pair induced free radical grafting reaction is a promising approach to conjugate phenolic groups with chitosan (CS). In order to reveal the exact mechanisms of the AA/H 2 O 2 redox pair induced grafting reaction, free radicals generated in the AA/H 2 O 2 redox system were compared with hydroxyl radical ( • OH) produced in the Fe 2+ /H 2 O 2 redox system. Moreover, the structural and physicochemical properties of caffeic acid grafted CS (CA-g-CS) synthesized in these two redox systems were compared. Results showed that only ascorbate radical (Asc •- ) was produced in the AA/H 2 O 2 system. The reaction between Asc •- and CS produced novel carbon-centered radicals, whereas no new free radicals were detected when • OH reacted with CS. Thin layer chromatography, UV-vis, Fourier transform infrared, and nuclear magnetic resonance spectroscopic analyses all confirmed that CA was successfully grafted onto CS through Asc •- . However, CA could be hardly grafted onto CS via • OH. CA-g-CS synthesized through Asc •- exhibited lower thermal stability and crystallinity than the reaction product obtained through • OH. For the first time, our results demonstrated that the synthesis of CA-g-CS in the AA/H 2 O 2 redox system was mediated by Asc •- rather than • OH.

  10. Phase behavior of fluorocarbon and hydrocarbon double-chain hydroxylated and galactosylated amphiphiles and bolaamphiphiles. Long-term shelf-stability of their liposomes.

    Science.gov (United States)

    Clary, L; Gadras, C; Greiner, J; Rolland, J P; Santaella, C; Vierling, P; Gulik, A

    1999-06-01

    This paper describes the morphological characterization, by freeze-fracture electron microscopy, and the thermotropic phase behavior, by differential scanning calorimetry and/or X-ray scattering, of aqueous dispersions of various hydroxylated and galactosylated double-chain amphiphiles and bolaamphiphiles, several of them containing one or two hydrophobic fluorocarbon chains. Colloidal systems are observed in water with the hydroxylated hydrocarbon or fluorocarbon bolaamphiphiles only when they are dispersed with a co-amphiphile such as rac-1,2-dimyristoylphosphatidylcholine (DMPC) or rac-1,2-distearoylphosphatidylcholine (DSPC). Liposomes are formed providing the relative content of bolaamphiphiles does not exceed 20% mol. Most of these liposomes can be thermally sterilized and stored at room temperature for several months without any significant modification of their size and size distribution. The hydrocarbon galactosylated bolaamphiphile HO[C24][C12]Gal forms in water a lamellar phase (the gel to liquid-crystal phase transition is complete at 45 degrees C) and a Im3m cubic phase above 47 degrees C. The fluorocarbon HO[C24][F6C5]Gal analog displays a more complex and metastable phase behavior. The fluorinated non-bolaform galactosylated [F8C7][C16]AEGal and SerGal amphiphiles form lamellar phases in water. Low amounts (10% molar ratio) of the HO[C24][F6C5]Gal or HO[C24][C12]Gal bolaamphiphiles or of the single-headed [F8C7][C16]AEGal improve substantially the shelf-stability of reference phospholipon/cholesterol 2/1 liposomes. These liposomes when co-formulated with a single-headed amphiphile from the SerGal series are by far less stable.

  11. Human metabolism and excretion kinetics of the fragrance lysmeral after a single oral dosage.

    Science.gov (United States)

    Scherer, Max; Koch, Holger M; Schütze, Andre; Pluym, Nikola; Krnac, Dusan; Gilch, Gerhard; Leibold, Edgar; Scherer, Gerhard

    2017-03-01

    2-(4-tert-Butylbenzyl)propionaldehyde, also known as lysmeral, lilial or lily-aldehyde (CAS No 80-54-6) is a synthetic fragrance used in a variety of consumer products like perfumes, after shave lotions, cosmetics and others. Due to its broad application, lysmeral was selected for the development of a biomonitoring method for the general population within the frame of the cooperation project of the Federal Ministry for the Environment (BMUB) and the German Chemical Industry Association (VCI). The project also comprises the identification of suitable biomarkers of exposure in human urine as well as basic toxicokinetic data after defined, experimental exposure. For this purpose, 5 healthy subjects were orally dosed once with 5.26mg lysmeral. Urine was collected immediately before and for 48h after administration of the fragrance. The lysmeral metabolites lysmerol, lysmerylic acid, hydroxylated lysmerylic acid and 4-tert-butylbenzoic acid (TBBA) were determined in all urine samples by a newly developed UPLC-MS/MS (ultra-high pressure liquid chromatography combined with tandem mass spectrometry) method. Peak excretion for all metabolites occurred between 2 and 5h after oral application, with the primary metabolites (lysmerol and lysmerylic acid) being excreted about 1h earlier than the secondary metabolites (hydroxylated lysmerylic acid and TBBA). More than 90% of all measured lysmeral metabolites were excreted after 12h, with the renal excretion being virtually complete after 48h. After this time period, TBBA, lysmerol, lysmerylic acid and hydroxyl-lysmerylic acid represent on average 14.3, 1.82, 0.20 and 0.16%, respectively, of the dose administered. In total, the 4 metabolites determined represent about 16.5% of the dose. With the conversion factors derived from the controlled human study, we estimated median exposure doses for lysmeral in a group of 40 human volunteers from the general population of approximately 140-220μg per day. In conclusion, the lysmeral

  12. Cardiac magnetic resonance and the need for routine cardiac catheterization in single ventricle patients prior to Fontan: a comparison of 3 groups: pre-Fontan CMR versus cath evaluation.

    Science.gov (United States)

    Fogel, Mark A; Pawlowski, Thomas W; Whitehead, Kevin K; Harris, Matthew A; Keller, Marc S; Glatz, Andrew C; Zhu, Winnie; Shore, David; Diaz, Laura K; Rome, Jonathan J

    2012-09-18

    This study investigated whether cardiac magnetic resonance (CMR) and echocardiography (echo) can replace catheterization (cath) for routine evaluation prior to Fontan and under what circumstances CMR and cath are used together. Routine cath prior to Fontan has been utilized for years; noninvasive methods, however, may be sufficient. This study reviews clinical data in 119 consecutive patients investigating 3 groups: those who underwent CMR alone (MR; n = 41), cath alone (C; n = 41), or both cath and CMR (C+M; n = 37) prior to Fontan. No clinically significant differences were noted in patient characteristics, hemodynamics, or clinical status prior to or after surgery between the C and MR groups. CMR added information in 82%. There were no discrepant findings between CMR and cath data in the C+M group. Diagnostic success was ≥95% in all groups. Of those undergoing Fontan completion, the C+M group had similar outcomes to C and MR; C and CMR were utilized in combination to assess aortopulmonary collaterals or the need for an intervention or evaluate its success. Echo could not delineate pulmonary arterial anatomy in 46% to 53% of patients. The C+M and C groups were exposed to 6.8 ± 4.1 mSv of radiation. Single ventricle patients not requiring an intervention can undergo successful Fontan completion with CMR and echo alone with similar short-term outcomes to C, which was used as a control, preventing an invasive test and exposure to radiation. CMR can add information in a significant number of patients. Cath and CMR are utilized together for interventions and assessment of aortopulmonary collaterals. Copyright © 2012 American College of Cardiology Foundation. Published by Elsevier Inc. All rights reserved.

  13. Stability, electrochemical behaviors and electronic structures of iron hydroxyl-phosphate

    Energy Technology Data Exchange (ETDEWEB)

    Wang Zhongli; Sun Shaorui; Li Fan; Chen Ge [College of Environmental and Energy Engineering, Beijing University of Technology, Pingleyuan 100, Chaoyang District, Beijing 100022 (China); Xia Dingguo, E-mail: dgxia@bjut.edu.cn [College of Environmental and Energy Engineering, Beijing University of Technology, Pingleyuan 100, Chaoyang District, Beijing 100022 (China); Zhao Ting; Chu Wangsheng [Institute of High Energy Physics, Chinese Academy of Sciences, Beijing 100049 (China); University of Science and Technology of China, Hefei 230026 (China); Wu Ziyu, E-mail: wuzy@ihep.ac.cn [Institute of High Energy Physics, Chinese Academy of Sciences, Beijing 100049 (China); University of Science and Technology of China, Hefei 230026 (China)

    2010-09-01

    Iron hydroxyl-phosphate with a uniform spherical particle size of around 1 {mu}m, a compound of the type Fe{sub 2-y}{open_square}{sub y}(PO{sub 4})(OH){sub 3-3y}(H{sub 2}O){sub 3y-2} (where {open_square} represents a vacancy), has been synthesized by hydrothermal methods. The particles are composed of spheres of diameter <100 nm. The compound exhibits good electrochemical performance, with reversible capacities of around 150 mAh g{sup -1} and 120 mAh g{sup -1} at current densities of 170 mA g{sup -1} and 680 mA g{sup -1}, respectively. The stability of crystal structure of this material was studied by TGA and XRD which show that the material remains stable at least up to the temperature 200 deg. C. Investigation of the electronic structure of the iron hydroxyl-phosphate by GGA + U calculation has indicated that it has a better electronic conductivity than LiFePO{sub 4}.

  14. Ultrasound Assisted Synthesis of Hydroxylated Soybean Lecithin from Crude Soybean Lecithin as an Emulsifier.

    Science.gov (United States)

    Chiplunkar, Pranali P; Pratap, Amit P

    2017-10-01

    Soybean lecithin is a by-product obtained during degumming step of crude soybean oil refining. Crude soybean lecithin (CSL) contains major amount of phospholipids (PLs) along with minor amount of acylglycerols, bioactive components, etc. Due to presence of PLs, CSL can be used as an emulsifier. Crude soybean lecithin (CSL) was utilized to synthesize hydroxylated soybean lecithin (HSL) by hydroxylation using hydrogen peroxide and catalytic amount of lactic acid to enhance the hydrophilicity and emulsifying properties of CSL. To reduce the reaction time and to increase rate of reaction, HSL was synthesized under ultrasound irradiation. The effect of different operating parameters such as lactic acid, hydrogen peroxide, temperature, ultrasonic power and duty cycle in synthesis of HSL were studied and optimized. The surface tension (SFT), interfacial tension (IFT) and the critical micelle concentration (CMC) of the HSL (26.11 mN/m, 2.67 mN/m, 112 mg/L) were compared to CSL (37.53 mN/m, 6.22 mN/m, 291 mg/L) respectively. The HSL has better emulsion stability and low foaming characteristics as compared to CSL. Therefore, the product as an effective emulsifier can be used in food, pharmacy, lubricant, cosmetics, etc.

  15. Hydroxyl radical and ozone initiated photochemical reactions of 1,3-butadiene

    Science.gov (United States)

    Liu, Xiaoyu; Jeffries, Harvey E.; Sexton, Kenneth G.

    1,3-Butadiene, classified as hazardous in the 1990 Clean Air Act Amendments, is an important ambient air pollutant. Understanding its atmospheric transformation is useful for its own sake, and is also helpful for eliciting isoprene's fate in the atmosphere (isoprene dominates the biogenic emissions in US). In this paper, samples from both hydroxyl- and ozone-initiated photooxidation of 1,3-butadiene were analyzed by derivatization with O- (2,3,4,5,6-pentafluorobenzyl)-hydroxylamine followed by separation and detection by gas chromatography/ion trap mass spectrometry to detect and identify carbonyl compounds. The following carbonyls were observed: formaldehyde, acrolein, glycolaldehyde, glycidaldehyde, 3-hydroxy-propanaldehyde, hydroxy acetone, and malonaldehyde, which can be classified into three categories: epoxy carbonyls, hydroxyl carbonyls, and di-carbonyls. Three non-carbonyls, furan, 1,3-buatdiene monoxide, and 1,3-butadiene diepoxide, were also found. To confirm their identities, both commercially available and synthesized standards were used. To investigate the mechanism of 1,3-butadiene, separate batch reactor experiments for acrolein and 1,3-butadiene monoxide were carried out. Time series samples for several products were also taken. When necessary, computational chemistry methods were also employed. Based on these results, various schemes for the reaction mechanism are proposed.

  16. Metabolism of diclofenac in plants--hydroxylation is followed by glucose conjugation.

    Science.gov (United States)

    Huber, Christian; Bartha, Bernadett; Schröder, Peter

    2012-12-01

    Pharmaceuticals from human or veterinary medication form a new class of micropollutants that poses a serious threat to our aquatic environment and its organisms. The intensively used nonsteroidal anti-inflammatory drug diclofenac is found in the environment worldwide due to its poor elimination during waste water treatment processes. In order to test phytoremediation as a tool for the removal of this drug from waste water, the uptake of the compound into plant tissues and its metabolic pathway was addressed using Hordeum vulgare (barley) and a hairy root cell culture of Armoracia rusticana (horse radish) as model species. Diclofenac is taken up by plants and undergoes rapid metabolization; already after 3h of exposure the drug and its metabolites could be detected in the plant tissues. Similar to its fate in mammalian cells the drug is activated in a phase I reaction resulting in the hydroxylated metabolite 4'OH-diclofenac which is conjugated subsequently in phase II to a glucopyranoside, a typical plant specific metabolite. After exposure to 10 and 100 μM diclofenac a concentration dependent formation of the hydroxylated metabolite was observed, while the formation of the phase II metabolite OH-diclofenac glucopyranoside was not positively affected by the higher concentration. To our knowledge this is the first time these two human painkiller metabolites are shown to occur in plant tissues. Copyright © 2012 Elsevier B.V. All rights reserved.

  17. UVA-induced reset of hydroxyl radical ultradian rhythm improves temporal lipid production in Chlorella vulgaris.

    Science.gov (United States)

    Balan, Ranjini; Suraishkumar, G K

    2014-01-01

    We report for the first time that the endogenous, pseudo-steady-state, specific intracellular levels of the hydroxyl radical (si-OH) oscillate in an ultradian fashion (model system: the microalga, Chlorella vulgaris), and also characterize the various rhythm parameters. The ultradian rhythm in the endogenous levels of the si-OH occurred with an approximately 6 h period in the daily cycle of light and darkness. Further, we expected that the rhythm reset to a shorter period could rapidly switch the cellular redox states that could favor lipid accumulation. We reset the endogenous rhythm through entrainment with UVA radiation, and generated two new ultradian rhythms with periods of approximately 2.97 h and 3.8 h in the light phase and dark phase, respectively. The reset increased the window of maximum lipid accumulation from 6 h to 12 h concomitant with the onset of the ultradian rhythms. Further, the saturated fatty acid content increased approximately to 80% of total lipid content, corresponding to the peak maxima of the hydroxyl radical levels in the reset rhythm. © 2014 American Institute of Chemical Engineers.

  18. Suitability of the hydrocarbon-hydroxylating molybdenum-enzyme ethylbenzene dehydrogenase for industrial chiral alcohol production.

    Science.gov (United States)

    Tataruch, M; Heider, J; Bryjak, J; Nowak, P; Knack, D; Czerniak, A; Liesiene, J; Szaleniec, M

    2014-12-20

    The molybdenum/iron-sulfur/heme protein ethylbenzene dehydrogenase (EbDH) was successfully applied to catalyze enantiospecific hydroxylation of alkylaromatic and alkylheterocyclic compounds. The optimization of the synthetic procedure involves use of the enzyme in a crude purification state that saves significant preparation effort and is more stable than purified EbDH without exhibiting unwanted side reactions. Moreover, immobilization of the enzyme on a crystalline cellulose support and changes in reaction conditions were introduced in order to increase the amounts of product formed (anaerobic atmosphere, electrochemical electron acceptor recycling or utilization of ferricyanide as alternative electron acceptor in high concentrations). We report here on an extension of effective enzyme activity from 4h to more than 10 days and final product yields of up to 0.4-0.5g/l, which represent a decent starting point for further optimization. Therefore, we expect that the hydrocarbon-hydroxylation capabilities of EbDH may be developed into a new process of industrial production of chiral alcohols. Copyright © 2014 Elsevier B.V. All rights reserved.

  19. Concentration-dependent photodegradation kinetics and hydroxyl-radical oxidation of phenicol antibiotics.

    Science.gov (United States)

    Li, Kai; Zhang, Peng; Ge, Linke; Ren, Honglei; Yu, Chunyan; Chen, Xiaoyang; Zhao, Yuanfeng

    2014-09-01

    Thiamphenicol and florfenicol are two phenicol antibiotics widely used in aquaculture and are ubiquitous as micropollutants in surface waters. The present study investigated their photodegradation kinetics, hydroxyl-radical (OH) oxidation reactivities and products. Firstly, the photolytic kinetics of the phenicols in pure water was studied as a function of initial concentrations (C0) under UV-vis irradiation (λ>200nm). It was found that the kinetics was influenced by C0. A linear plot of the pseudo-first-order rate constant vs C0 was observed with a negative slope. Secondly, the reaction between the phenicol antibiotics and OH was examined with a competition kinetic method under simulated solar irradiation (λ>290nm), which quantified their bimolecular reaction rate constants of (2.13±0.02)×10(9)M(-1)s(-1) and (1.82±0.10)×10(9)M(-1)s(-1) for thiamphenicol and florfenicol, respectively. Then the corresponding OH oxidated half-lives in sunlit surface waters were calculated to be 90.5-106.1h. Some main intermediates were formed from the reaction, which suggested that the two phenicols underwent hydroxylation, oxygenation and dehydrogenation when OH existed. These results are of importance to assess the phenicol persistence in wastewater treatment and sunlit surface waters. Copyright © 2014 Elsevier Ltd. All rights reserved.

  20. Synthesis of hydroxylated sterols in transgenic Arabidopsis plants alters growth and steroid metabolism.

    Science.gov (United States)

    Beste, Lisa; Nahar, Nurun; Dalman, Kerstin; Fujioka, Shozo; Jonsson, Lisbeth; Dutta, Paresh C; Sitbon, Folke

    2011-09-01

    To explore mechanisms in plant sterol homeostasis, we have here increased the turnover of sterols in Arabidopsis (Arabidopsis thaliana) and potato (Solanum tuberosum) plants by overexpressing four mouse cDNA encoding cholesterol hydroxylases (CHs), hydroxylating cholesterol at the C-7, C-24, C-25, or C-27 positions. Compared to the wild type, the four types of Arabidopsis transformant showed varying degrees of phenotypic alteration, the strongest one being in CH25 lines, which were dark-green dwarfs resembling brassinosteroid-related mutants. Gas chromatography-mass spectrometry analysis of extracts from wild-type Arabidopsis plants revealed trace levels of α and β forms of 7-hydroxycholesterol, 7-hydroxycampesterol, and 7-hydroxysitosterol. The expected hydroxycholesterol metabolites in CH7-, CH24-, and CH25 transformants were identified and quantified using gas chromatography-mass spectrometry. Additional hydroxysterol forms were also observed, particularly in CH25 plants. In CH24 and CH25 lines, but not in CH7 ones, the presence of hydroxysterols was correlated with a considerable alteration of the sterol profile and an increased sterol methyltransferase activity in microsomes. Moreover, CH25 lines contained clearly reduced levels of brassinosteroids, and displayed an enhanced drought tolerance. Equivalent transformations of potato plants with the CH25 construct increased hydroxysterol levels, but without the concomitant alteration of growth and sterol profiles observed in Arabidopsis. The results suggest that an increased hydroxylation of cholesterol and/or other sterols in Arabidopsis triggers compensatory processes, acting to maintain sterols at adequate levels.

  1. Hydroxyl radical induced cross-linking of cytosine and tyrosine in nucleohistone

    International Nuclear Information System (INIS)

    Gajewski, E.; Dizdaroglu, M.

    1990-01-01

    Hydroxyl radical induced formation of a DNA-protein cross-link involving cytosine and tyrosine in nucleohistone in buffered aqueous solution is reported. The technique of gas chromatography-mass spectrometry was used for this investigation. A γ-irradiated aqueous mixture of cytosine and tyrosine was first investigated in order to obtain gas chromatographic-mass spectrometric properties of possible cytosine-tyrosine cross-links. One cross-link was observed, and its structure was identified as the product from the formation of a covalent bond between carbon 6 of cytosine and carbon 3 of tyrosine. With the use of gas chromatography-mass spectrometry with selected-ion monitoring, this cytosine-tyrosine cross-link was identified in acidic hydrolysates of calf thymus nucleohistone γ-irradiated in N 2 O-saturated aqueous solution. The yield of this DNA-protein cross-link in nucleohistone was found to be a linear function of the radiation dose in the range of 100-500 Gy (J·kg -1 ). This yield amounted to 0.05 nmol·J -1 . Mechanisms underlying the formation of the cytosine-tyrosine cross-link in nucleohistone were proposed to involve radical-radical and/or radical addition reactions of hydroxyl adduct radicals of cytosine and tyrosine moieties, forming a covalent bond between carbon 6 of cytosine and carbon 3 of tyrosine. When oxygen was present in irradiated solutions, no cytosine-tyrosine cross-links were observed

  2. Remote stereocontrol by sulfinyl groups: reduction of delta-ketosulfoxides.

    Science.gov (United States)

    García Ruano, José L; Fernández-Ibáñez, M Angeles; Maestro, M Carmen; Rodríguez-Fernández, M Mercedes

    2005-03-04

    The reduction of delta-ketosulfoxides constitutes the first evidence of the efficiency of the sulfinyl group to control the stereoselectivity of 1,5-asymmetric induction processes. The use of DIBAL/Yb(OTf)3 or L-Selectride as the reducing agents provides delta-hydroxysulfoxides with the opposite configuration at the hydroxylic carbon in a highly stereoselective way.

  3. Aqueous benzene-diols react with an organic triplet excited state and hydroxyl radical to form secondary organic aerosol.

    Science.gov (United States)

    Smith, Jeremy D; Kinney, Haley; Anastasio, Cort

    2015-04-21

    Chemical processing in atmospheric aqueous phases, such as cloud and fog drops, can play a significant role in the production and evolution of secondary organic aerosol (SOA). In this work we examine aqueous SOA production via the oxidation of benzene-diols (dihydroxy-benzenes) by the triplet excited state of 3,4-dimethoxybenzaldehyde, (3)DMB*, and by hydroxyl radical, ˙OH. Reactions of the three benzene-diols (catechol (CAT), resorcinol (RES) and hydroquinone (HQ)) with (3)DMB* or ˙OH proceed rapidly, with rate constants near diffusion-controlled values. The two oxidants exhibit different behaviors with pH, with rate constants for (3)DMB* increasing as pH decreases from pH 5 to 2, while rate constants with ˙OH decrease in more acidic solutions. Mass yields of SOA were near 100% for all three benzene-diols with both oxidants. We also examined the reactivity of atmospherically relevant mixtures of phenols and benzene-diols in the presence of (3)DMB*. We find that the kinetics of phenol and benzene-diol loss, and the production of SOA mass, in mixtures are generally consistent with rate constants determined in experiments containing a single phenol or benzene-diol. Combining our aqueous kinetic and SOA mass yield data with previously published gas-phase data, we estimate a total SOA production rate from benzene-diol oxidation in a foggy area with significant wood combustion to be nearly 0.6 μg mair(-3) h(-1), with approximately half from the aqueous oxidation of resorcinol and hydroquinone, and half from the gas-phase oxidation of catechol.