Sample records for maximum h2o storage

  1. Heat-Storage Modules Containing LiNO3-3H2O and Graphite Foam

    Bootle, John


    A heat-storage module based on a commercial open-cell graphite foam (Poco-Foam or equivalent) imbued with lithium nitrate trihydrate (LiNO3-3H2O) has been developed as a prototype of other such modules for use as short-term heat sources or heat sinks in the temperature range of approximately 28 to 30 C. In this module, the LiNO3-3H2O serves as a phase-change heat-storage material and the graphite foam as thermally conductive filler for transferring heat to or from the phase-change material. In comparison with typical prior heat-storage modules in which paraffins are the phase-change materials and aluminum fins are the thermally conductive fillers, this module has more than twice the heat-storage capacity per unit volume.

  2. Study of the reversible water vapour sorption process of MgSO4.7H2O and MgCl2.6H2O under the conditions of seasonal solar heat storage

    Ferchaud, C. J.; Zondag, H. A.; Veldhuis, J. B. J.; de Boer, R.


    The characterization of the structural, compositional and thermodynamic properties of MgSO4.7H2O and MgCl2.6H2O has been done using in-situ X-ray Diffraction and thermal analyses (TG/DSC) under practical conditions for seasonal heat storage (Tmax=150°C, p(H2O)=13 mbar). This study showed that these two materials release heat after a dehydration/hydration cycle with energy densities of 0.38 GJ/m3 for MgSO4.7H2O and 0.71 GJ/m3 MgCl2.6H2O. The low heat release found for MgSO4.7H2O is mainly attributed to the amorphization of the material during the dehydration performed at 13 mbar which reduces its sorption capacity during the rehydration. MgCl2.6H2O presents a high energy density which makes this material interesting for seasonal heat storage in domestic applications. This material would be able to fulfil the winter heat demand of a passive house estimated at 6 GJ with a packed bed reactor of 8.5 m3. However, a seasonal heat storage system built with this material should be carefully set with a restricted temperature at 40°C for the hydration reaction to avoid the liquefaction of the material at lower temperature which limits its performances for long term storage.

  3. Application of MgCl2.6H2O for thermochemical seasonal solar heat storage

    Zondag, H.A. [Eindhoven University of Technology, Eindhoven (Netherlands); Van Essen, V.M.; Bleijendaal, L.P.J.; Kikkert, B.W.J.; Bakker, M. [ECN Solar Energy, Petten (Netherlands)


    The heat demand in the summer can be completely fulfilled using solar heat, but in the winter the heat demand is exceeding the solar supply. A solution is to store the excess of solar energy in the summer, and to use it to fulfill the heat demand in the winter. Water is traditionally used for storing heat (e.g. solar boiler), but seasonal heat storage requires large water tanks (>40m{sup 3}) that are too large to be placed inside a residential building. An alternative option is to store heat by means of chemical processes using the reversible reaction: A+B->C+heat. With thermochemical heat storage, energy storage densities can be reached that are ten times higher than for heat storage in water. Additionally, after the thermochemical material has been charged, the heat can be stored for a very long time without losses. Interesting materials are cheap, non-toxic, non-corrosive, have sufficient energy storage density and have reaction temperatures in the proper range. A large materials inventory by ECN identified a number of interesting materials, including magnesium chloride hexahydrate (MgCl2.6H2O) as one of the most promising materials for seasonal heat storage.

  4. Core-shell Prussian blue analogue molecular magnet Mn(1.5)[Cr(CN)6]·mH2O@Ni(1.5)[Cr(CN)6]·nH2O for hydrogen storage.

    Bhatt, Pramod; Banerjee, Seemita; Anwar, Sharmistha; Mukadam, Mayuresh D; Meena, Sher Singh; Yusuf, Seikh M


    Core-shell Prussian blue analogue molecular magnet Mn1.5[Cr(CN)6]·mH2O@Ni1.5[Cr(CN)6]·nH2O has been synthesized using a core of Mn1.5[Cr(CN)6]·7.5H2O, surrounded by a shell of Ni1.5[Cr(CN)6]·7.5H2O compound. A transmission electron microscopy (TEM) study confirms the core-shell nature of the nanoparticles with an average size of ∼25 nm. The core-shell nanoparticles are investigated by using x-ray diffraction (XRD), energy-dispersive X-ray spectroscopy (EDS) and elemental mapping, X-ray photoelectron spectroscopy (XPS), thermogravimetric analysis (TGA), and infrared (IR) spectroscopy. The Rietveld refinement of the XRD pattern reveals that the core-shell compound has a face-centered cubic crystal structure with space group Fm3m. The observation of characteristic absorption bands in the range of 2000-2300 cm(-1) in IR spectra corresponds to the CN stretching frequency of Mn(II)/Ni(II)-N≡C-Cr(III) sequence, confirming the formation of Prussian blue analogues. Hydrogen absorption isotherm measurements have been used to investigate the kinetics of molecular hydrogen adsorption into core-shell compounds of the Prussian blue analogue at low temperature conditions. Interestingly, the core-shell compound shows an enhancement in the hydrogen capacity (2.0 wt % at 123 K) as compared to bare-core and bare-shell compounds. The hydrogen adsorption capacity has been correlated with the specific surface area and TGA analysis of the core-shell compound. To the best of our knowledge, this is the first report on the hydrogen storage properties of core-shell Prussian blue analogue molecular magnet that could be useful for hydrogen storage applications.

  5. Energy storage for a lunar base by the reversible chemical reaction: CaO+H2O reversible reaction Ca(OH)2

    Perez-Davis, Marla E.; Difilipo, Frank


    A thermochemical solar energy storage concept involving the reversible reaction CaO + H2O yields Ca(OH)2 is proposed as a power system element for a lunar base. The operation and components of such a system are described. The CaO/H2O system is capable of generating electric power during both the day and night. The specific energy (energy to mass ratio) of the system was estimated to be 155 W-hr/kg. Mass of the required amount of CaO is neglected since it is obtained from lunar soil. Potential technical problems, such as reactor design and lunar soil processing, are reviewed.

  6. Water Transport in MgSO4·7H2O during Dehydration in View of Thermal Storage

    Donkers, P.A.J.; Beckert, S.; Pel, L.; Stallmach, F.; Steiger, M.; Adan, O.C.G.


    The water phases in a MgSO4·7H2O crystal during heating were studied with the help of NMR. The thermogravimetric analysis (TGA) data showed that the heating rate has a strong effect on the dehydration process. NMR experiments showed that pore water, i.e., an aqueous solution of MgSO4, was produced d

  7. Thermophysical Characterization of MgCl2·6H2O, Xylitol and Erythritol as Phase Change Materials (PCM for Latent Heat Thermal Energy Storage (LHTES

    Stephan Höhlein


    Full Text Available The application range of existing real scale mobile thermal storage units with phase change materials (PCM is restricted by the low phase change temperature of 58 ∘ C for sodium acetate trihydrate, which is a commonly used storage material. Therefore, only low temperature heat sinks like swimming pools or greenhouses can be supplied. With increasing phase change temperatures, more applications like domestic heating or industrial process heat could be operated. The aim of this study is to find alternative PCM with phase change temperatures between 90 and 150 ∘ C . Temperature dependent thermophysical properties like phase change temperatures and enthalpies, densities and thermal diffusivities are measured for the technical grade purity materials xylitol (C 5 H 12 O 5 , erythritol (C 4 H 10 O 4 and magnesiumchloride hexahydrate (MCHH, MgCl 2 · 6H 2 O. The sugar alcohols xylitol and erythritol indicate a large supercooling and different melting regimes. The salt hydrate MgCl 2 · 6H 2 O seems to be a suitable candidate for practical applications. It has a melting temperature of 115.1 ± 0.1 ∘ C and a phase change enthalpy of 166.9 ± 1.2 J / g with only 2.8 K supercooling at sample sizes of 100 g . The PCM is stable over 500 repeated melting and solidification cycles at differential scanning calorimeter (DSC scale with only small changes of the melting enthalpy and temperature.

  8. Thermochemical seasonal solar heat storage with MgCl2.6H2O. First upscaling of the reactor

    Zondag, H.A. [Eindhoven University of Technology, Eindhoven (Netherlands); Kikkert, B.W.J.; Smeding, S.; Bakker, M. [ECN Solar Energy, Petten (Netherlands)


    In the summer, the available of solar heat exceeds the total heat demand of a building, but in the winter the heat demand is exceeding the solar supply. For the future conversion of a passive house into an energy neutral house, a solution is to store the excess of solar energy in summer, and to use it to meet the heat demand in winter. Water is traditionally used for storing heat (e.g. solar boiler), but seasonal heat storage requires large water tanks (>40m{sup 3}) that are too large to be placed inside an average family house. An alternative option is to store heat by means of chemical processes using the reversible reaction: A + B <-> C + heat. Such thermochemical heat storage has a 5 to 10 times higher energy storage density than water, with the additional benefit that, after charging, the heat can be stored for a long time without losses. With thermochemical materials, the entire heating demand of a low-energy house during winter could be met using a storage volume of 4 to 8 m3, that is charged during summer by solar collectors. Because of the large amount of thermochemical material required for such storages, as well as the strict safety regulations in the built environment, safety and cost of the materials are important aspects. Because of safety criteria, the focus in the present research is on water as the sorbate. Because of low cost and high storage density, the focus is on salt hydrates, rather than silicagel or zeolites. In this paper, R and D on system aspects, materials selection and characterization, as well as on reactor concepts is presented.

  9. Limestone calcination under calcium-looping conditions for CO2 capture and thermochemical energy storage in the presence of H2O: an in situ XRD analysis.

    Valverde, Jose Manuel; Medina, Santiago


    This work reports an in situ XRD analysis of whether the calcination/carbonation behavior of natural limestone (CaCO3) is affected by the addition of H2O to the calciner at a very low concentration under relevant Calcium-Looping (CaL) conditions for CO2 capture in coal fired power plants (CFPP) and Thermochemical Energy Storage (TCES) in Concentrated Solar Power plants (CSP). Previous studies have demonstrated that the presence of steam in the calciner at a high concentration yields a significant increase in the reaction rate. However, a further undesired consequence is the serious deterioration of the CaO mechanical strength, which would lead to particle attrition and mass loss in any CaL process based on the use of circulating fluidized beds. The results presented in this manuscript on the time evolution of the wt% and crystallite size of the phases involved in the calcination/carbonation reactions indicate that the calcination rate is still notably increased by the presence of H2O at very low concentrations whereas the reactivity toward carbonation and crystal structure of the formed CaO are not essentially affected, which suggests that the CaO mechanical strength is not impaired. Thus, the benefit of using steam for calcination in the CaL process could be still retained while at the same time particle attrition would not be promoted.

  10. The role of chemical additives to the phase change process of CaCl2.6H2O to optimize its performance as latent heat energy storage system

    Sutjahja, I. M.; U, S. Rahayu A.; Kurniati, Nia; Pallitine, Ivyalentine D.; Kurnia, D.


    CaCl2.6H2O is one of salt hydrate based phase change material (PCM) which is suitable for room air-temperature stabilizer because it has the melting temperature just above the human comfort zone temperature (Tm ∼⃒ 29 oC) and a relatively large heat entalphy (AH ∼⃒ 190 kJ/kg). This paper reports the role of the type of chemical additives to PCM CaCl2.6H2O to the phase change process throughout the solidification process or heat release in order to optimize its performance as latent heat energy storage system. In this research we used several kinds of chemical additive, namely SrCl2.6H2O (1.0 wt%), BaCO3 (0.5 wt%), and K2CO3 (0.5 wt%). In terms of its latent time for phase change process the order the effectiveness of those chemical additives are reduced from SrCl2.6H2O, BaCO3and K2CO3. We found that this is also related to their role in suppression supercooling and phase separation effects which occurs during crystallization process of CaCl2.6H2O.

  11. H2O Paradox and its Implications on H2O in Moon

    Zhang, Youxue


    second scenario is unlikely on Moon because there was unlikely plate tectonics, and because there is no similar H2O-rich transition zone or D" layer due to the much lower maximum pressure in Moon. In the third scenario, volatiles from an extralunar source would likely be lost from the high vacuum environment of the lunar surface, meaning that it would not impact on the H2O content estimation. [1] McDonough & Sun (1995) Chem. Geol. 120, 223. [2] Palme & O'Neill (2014) Treatise on Geochemistry 3, 1. [3] Zhang (2014) Treatise on Geochemistry 6, 37. [4] Zhang & Zindler (1989) JGR 94, 13719. [5] Hui et al. (2013) Nature Geosci. 6, 177. [6] Chen et al. (2015) EPSL 427, 37. [7] Albarede et al. (2015) MPS 50, 568. [8] Sobolev et al. (2016) Nature 531, 628. [9] Chyba (1987) Nature 330, 632. [10] Hartogh et al. (2011) Nature 478, 218. [11] Hui et al. (2016) Goldschmidt Conf. Abstr.

  12. The effectiveness of organic PCM based on lauric acid from coconut oil and inorganic PCM based on salt hydrate CaCl2.6H2o as latent heat energy storage system in Indonesia

    U, Sri Rahayu A.; Putri, Widya A.; Sutjahja, I. M.; Kurnia, D.; Wonorahardjo, S.


    A latent heat energy storage system utilizing phase change materials (PCM) is an alternative strategy to reduce the use of Air Conditioning (AC) system in big cities in Indonesia in order for energy conservation in the future. In this research we used two kinds of materials, namely organic PCM based on lauric acid from coconut oil (CO) and inorganic PCM based on salt hydrate CaCl2.6H2O, because they have thermophysical parameters suitable for human's thermal comfort application in the building. The CO which contained more than 50% lauric acid has the melting temperature (Tm ) of about 26 °C and heat entalphy (ΔH) around 103 kJ/kg, while CaCl2.6H2O has the melting point of 29 °C and heat entalphy of 190 kJ/kg. In this paper we report the effectiveness of those two kinds of PCM in reducing the air temperature as one of some criteria for human's thermal comfort. The experiments were performed in a close and adiabatic room and the time-temperature measurements were done automatically using Arduino microcontroller and LM35 temperature sensor connected to the PC.

  13. An experimental study of basaltic glass-H2O-CO2 interaction at 22 and 50 °C: Implications for subsurface storage of CO2

    Galeczka, Iwona; Wolff-Boenisch, Domenik; Oelkers, Eric H.; Gislason, Sigurdur R.


    degassed at the outlet. Substantial differences were found between the results of geochemical modelling calculations and the observed chemical evolution of the fluids during the experiments. These differences underscore the need to improve the models before they can be used to predict with confidence the fate and consequences of carbon dioxide injected into the subsurface. The pH increase from 3.4 to 4.5 of the CO2-rich inlet fluid does not immobilize toxic elements at ambient temperature but immobilizes Al and Cr at 50 °C. This indicates that further neutralization of CO2-charged water is required for decreased toxic element mobility. The CO2-charged water injection enhances the mobility of redox sensitive Fe2+ significantly making it available for the storage of injected carbon as iron carbonate minerals. The precipitation of aluminosilicates likely occurred at a pH of 4.2-4.5 in CO2-charged waters. These secondary phases can (1) fill the available pore space and therefore clog the host rock in the vicinity of the injection well, and (2) incorporate some divalent cations limiting their availability for carbon storage. The inability of simple reactive transport models to describe accurately the fluid evolution in this well constrained one dimensional flow system suggests that significant improvements need to be made to such models before we can predict with confidence the fate and consequences of injecting carbon dioxide into the subsurface. Column reactors such as that used in this study could be used to facilitate ex situ carbon mineral storage. Carbonate precipitation at the outlet of the reactor suggests that the harvesting of divalent metals from rocks using CO2-charged waters could potentially be upscaled to an industrial carbonation process.

  14. Application of Na2SO4·10H2O thermal energy storage materials in the vegetable greenhouse%十水硫酸钠储热材料在农业大棚中的应用

    徐燕; 刘伟; 于观成; 王智军; 黄学金


    就蔬菜大棚夜间需要提升温度的需求,提出使用储热材料的基本设想.经对不同的储热材料进行对比分析,决定采用Na2SO4.10H20作为实验用储热材料.实验结果证明,在晴天,该储热材料白天储存的太阳能可使塑料大棚内日平均气温提高2.4℃,夜间平均气温提高5.4 ℃.%In order to raise the temperature of vegetable greenhouse since its temperature might be low at night,the basic idea of using thermal energy storage material was proposed.To make comparative analysis of different thermal energy storage materials, Na2SO4 · 10H2O is used as experimental materials for thermal storage.Thermal energy storage materials store excess solar energy during the day, increasing the average temperature of plastic canopy to 2.4 ℃, the average night temperature to 5.4 ℃.

  15. Photolysis of H2O-H2O2 Mixtures: The Destruction of H2O2

    Loeffler, M. J.; Fama, M.; Baragiola, R. A.; Carlson, R. W.


    We present laboratory results on the loss of H2O2 in solid H2O + H2O2 mixtures at temperatures between 21 and 145 K initiated by UV photolysis (193 nm). Using infrared spectroscopy and microbalance gravimetry, we measured the decrease of the 3.5 micrometer infrared absorption band during UV irradiation and obtained a photodestruction cross section that varies with temperature, being lowest at 70 K. We use our results, along with our previously measured H2O2 production rates via ionizing radiation and ion energy fluxes from the spacecraft to compare H2O2 creation and destruction at icy satellites by ions from their planetary magnetosphere and from solar UV photons. We conclude that, in many cases, H2O2 is not observed on icy satellite surfaces because the H2O2 photodestruction rate is much higher than the production rate via energetic particles, effectively keeping the H2O2 infrared signature at or below the noise level.

  16. Vibrational predissociation of ArH2O

    Bissonnette, C.; Clary, D. C.


    Accurate close-coupling calculations are used to investigate the vibrational predissociation of ArH2O as a function of the overall rotation J of the van der Waals complex. A full vibrational and rotational basis of H2O states is used in the calculation. The potential energy surface is of a form due to Cohen and Saykally and derived from far-infrared spectra, with an additional term to introduce the dependence on the vibrations of H2O. The linewidths calculated in this work show a maximum at J=6 and it is found that Fermi resonances affect dramatically the magnitude of the calculated linewidths. Good agreement with experimentally measured linewidths of Nesbitt and Lascola is achieved and the calculations provide a simple picture for the J dependence of the linewidths.

  17. Variations in H2O+/H2O ratios toward massive star-forming regions

    Wyrowski, F; Herpin, F; Baudry, A; Bontemps, S; Chavarria, L; Frieswijk, W; Jacq, T; Marseille, M; Shipman, R; van Dishoeck, E F; Benz, A O; Caselli, P; Hogerheijde, M R; Johnstone, D; Liseau, R; Bachiller, R; Benedettini, M; Bergin, E; Bjerkeli, P; Blake, G; Braine, J; Bruderer, S; Cernicharo, J; Codella, C; Daniel, F; di Giorgio, A M; Dominik, C; Doty, S D; Encrenaz, P; Fich, M; Fuente, A; Giannini, T; Goicoechea, J R; de Graauw, Th; Helmich, F; Herczeg, G J; Jørgensen, J K; Kristensen, L E; Larsson, B; Lis, D; McCoey, C; Melnick, G; Nisini, B; Olberg, M; Parise, B; Pearson, J C; Plume, R; Risacher, C; Santiago, J; Saraceno, P; Tafalla, M; van Kempen, T A; Visser, R; Wampfler, S; Yıldız, U A; Black, J H; Falgarone, E; Gerin, M; Roelfsema, P; Dieleman, P; Beintema, D; De Jonge, A; Whyborn, N; Stutzki, J; Ossenkopf, V


    Early results from the Herschel Space Observatory revealed the water cation H2O+ to be an abundant ingredient of the interstellar medium. Here we present new observations of the H2O and H2O+ lines at 1113.3 and 1115.2 GHz using the Herschel Space Observatory toward a sample of high-mass star-forming regions to observationally study the relation between H2O and H2O+ . Nine out of ten sources show absorption from H2O+ in a range of environments: the molecular clumps surrounding the forming and newly formed massive stars, bright high-velocity outflows associated with the massive protostars, and unrelated low-density clouds along the line of sight. Column densities per velocity component of H2 O+ are found in the range of 10^12 to a few 10^13 cm-2 . The highest N(H2O+) column densities are found in the outflows of the sources. The ratios of H2O+/H2O are determined in a range from 0.01 to a few and are found to differ strongly between the observed environments with much lower ratios in the massive (proto)cluster e...

  18. EPA H2O Software Tool

    EPA H2O allows user to: Understand the significance of EGS in Tampa Bay watershed; visually analyze spatial distribution of the EGS in Tampa Bay watershed; obtain map and summary statistics of EGS values in Tampa Bay watershed; analyze and compare potential impacts of development...

  19. EPA H2O User Manual

    EPA H2O is a software tool designed to support research being conducted in the Tampa Bay watershed to provide information, data, and approaches and guidance that communities can use to examine alternatives when making strategic decisions to support a prosperous and environmentall...

  20. The maximum water storage capacities in nominally anhydrous minerals in the mantle transition zone and lower mantle

    Inoue, T.; Yurimoto, H.


    Water is the most important volatile component in the Earth, and affects the physicochemical properties of mantle minerals, e.g. density, elastic property, electrical conductivity, thermal conductivity, rheological property, melting temperature, melt composition, element partitioning, etc. So many high pressure experiments have been conducted so far to determine the effect of water on mantle minerals. To clarify the maximum water storage capacity in nominally anhydrous mantle minerals in the mantle transition zone and lower mantle is an important issue to discuss the possibility of the existence of water reservoir in the Earth mantle. So we have been clarifying the maximum water storage capacity in mantle minerals using MA-8 type (KAWAI-type) high pressure apparatus and SIMS (secondary ion mass spectroscopy). Upper mantle mineral, olivine can contain ~0.9 wt% H2O in the condition just above 410 km discontinuity in maximum (e.g. Chen et al., 2002; Smyth et al., 2006). On the other hand, mantle transition zone mineral, wadsleyite and ringwoodite can contain significant amount (about 2-3 wt.%) of H2O (e.g. Inoue et al., 1995, 1998, 2010; Kawamoto et al., 1996; Ohtani et al., 2000). But the lower mantle mineral, perovskite can not contain significant amount of H2O, less than ~0.1 wt% (e.g. Murakami et al., 2002; Inoue et al., 2010). In addition, garnet and stishovite also can not contain significant amount of H2O (e.g. Katayama et al., 2003; Mookherjee and Karato, 2010; Litasov et al., 2007). On the other hand, the water storage capacities of mantle minerals are supposed to be significantly coupled with Al by a substitution with Mg2+, Si4+ or Mg2+ + Si4+, because Al3+ is the trivalent cation, and H+ is the monovalent cation. To clarify the degree of the substitution, the water contents and the chemical compositions of Al-bearing minerals in the mantle transition zone and the lower mantle were also determined in the Al-bearing systems with H2O. We will introduce the

  1. Single-crystal elastic properties of (Cs,Na)AlSi2O6.H2O pollucite: A zeolite with potential use for long-term storage of Cs radioisotopes

    Sanchez-Valle, Carmen; Chio, Chi-Hong; Gatta, G. Diego


    The single-crystal and aggregate elastic properties of the zeolite pollucite (Cs,Na)AlSi2O6ṡH2O, a potential host for Cs radionucleides in geological repositories, have been determined by Brillouin scattering spectroscopy at ambient conditions. The three nonzero individual elastic constants of cubic pollucite are: C11=105.0(1.3) GPa, C44=27.0(3) GPa, and C12=25.7(6) GPa. The Voigt-Reuss-Hill average of the aggregate bulk, shear modulus, Young's modulus and Poisson's ratio are KS=52.2(1.0) GPa, G=31.5(7) GPa, E=78.6(1.0) GPa, and ν =0.248(4), respectively. The bulk modulus of pollucite is 12.7% lower than that of the all-Na isotypic mineral analcime NaAlSi2O6ṡH2O whereas the shear moduli G are identical within mutual uncertainties. The higher compressibility of pollucite results from the weaker Cs-O bonds compared to Na-O bonds, suggesting strong control of the nature and configuration of the extraframework content on the behavior of the structure. The elastic properties of pollucite reported here will help in the prediction of its behavior as a geological barrier and in the modeling of the short-term and long-term safety of the Cs-repositories.

  2. Effects of H2O2 on Oxygen Supply in the Process of DCA Fermentation

    黄英明; 焦鹏; 李书良; 华玉涛; 曹竹安


    Long chain dicarboxylic acid (DCA) produced by Candida tropicalis is produced in an aerobic viscous fermentation system. The gas-liquid transport resistance can be overcome and the oxygen supply can be increased by adding hydrogen peroxide (H2O2) to the fermentation system. This paper shows that H2O2 can not only enhance the oxygen supply but also change the metabolism by inducing cytochrome P450, the key enzyme of α, ω-oxidation. When C. tropicalis was cultivated in a 3-liter bioreactor using the combination of aeration and hydrogen peroxide feeding, the DCA yield increased about 10% except at the beginning of H2O2 feeding. The experiments showed that the maximum activities of P450 could be induced at 2 mmol*L-1 H2O2. By adding H2O2, the DCA yield in a 22-liter bioreactor was increased 25.3% to 153.9 g/L.

  3. H2O and CO coadsorption on Co (0001): The effect of intermolecular hydrogen bond

    Jiawei, Wu; Chen, Jun; Guo, Qing; Su, Hai-Yan; Dai, Dongxu; Yang, Xueming


    The co-adsorption of CO and H2O on a Co(0001) surface at 100 K has been systematically studied using temperature programmed desorption (TPD) and density functional theory (DFT) calculations. While the TPD spectra of CO is almost not affected by the presence of H2O, the stabilization of H2O by co-adsorbed CO is found for the first time in a large coverage range (0.15 ML H2O is gradually separated into three peaks at 0.6 ML coverage. Those at lower and higher temperatures may be attributed to the repulsive interaction between H2O molecules and the attractive interaction between H2O and CO molecules, respectively. With increasing the coverage of predosed CO, not only the position of the high temperature peak shifts toward higher temperature (by about 15 K), but the intensity is greatly strengthened until a maximum is achieved when θCO = 0.36 ML. DFT calculations suggest that the attractive interaction between H2O and CO on Co(0001) originates from the formation of intermolecular hydrogen bonds. This work not only provides insights into water gas shift reactions with H2O and CO as reactants, but opens new avenues for a volume of catalytic process of technological importance.

  4. The H2O2-H2O Hypothesis: Extremophiles Adapted to Conditions on Mars?

    Houtkooper, Joop M.; Schulze-Makuch, Dirk


    The discovery of extremophiles on Earth is a sequence of discoveries of life in environments where it had been deemed impossible a few decades ago. The next frontier may be the Martian surface environment: could life have adapted to this harsh environment? What we learned from terrestrial extremophiles is that life adapts to every available niche where energy, liquid water and organic materials are available so that in principle metabolism and propagation are possible. A feasible adaptation mechanism to the Martian surface environment would be the incorporation of a high concentration of hydrogen peroxide in the intracellular fluid of organisms. The H2O2-H2O hypothesis suggests the existence of Martian organisms that have a mixture of H2O2 and H2O instead of salty water as their intracellular liquid (Houtkooper and Schulze-Makuch, 2007). The advantages are that the freezing point is low (the eutectic freezes at 56.5°C) and that the mixture is hygroscopic. This would enable the organisms to scavenge water from the atmosphere or from the adsorbed layers of water molecules on mineral grains, with H2O2 being also a source of oxygen. Moreover, below its freezing point the H2O2-H2O mixture has the tendency to supercool. Hydrogen peroxide is not unknown to biochemistry on Earth. There are organisms for which H2O2 plays a significant role: the bombardier beetle, Brachinus crepitans, produces a 25% H2O2 solution and, when attacked by a predator, mixes it with a fluid containing hydroquinone and a catalyst, which produces an audible steam explosion and noxious fumes. Another example is Acetobacter peroxidans, which uses H2O2 in its metabolism. H2O2 plays various other roles, such as the mediation of physiological responses such as cell proliferation, differentiation, and migration. Moreover, most eukaryotic cells contain an organelle, the peroxisome, which mediates the reactions involving H2O2. Therefore it is feasible that in the course of evolution, water-based organisms

  5. H2O2 space shuttle APU


    A cryogenic H2-O2 auxiliary power unit (APU) was developed and successfully demonstrated. It has potential application as a minimum weight alternate to the space shuttle baseline APU because of its (1) low specific propellant consumption and (2) heat sink capabilities that reduce the amount of expendable evaporants. A reference system was designed with the necessary heat exchangers, combustor, turbine-gearbox, valves, and electronic controls to provide 400 shp to two aircraft hydraulic pumps. Development testing was carried out first on the combustor and control valves. This was followed by development of the control subsystem including the controller, the hydrogen and oxygen control valves, the combustor, and a turbine simulator. The complete APU system was hot tested for 10 hr with ambient and cryogenic propellants. Demonstrated at 95 percent of design power was 2.25 lb/hp-hr. At 10 percent design power, specific propellant consumption was 4 lb/hp-hr with space simulated exhaust and 5.2 lb/hp-hr with ambient exhaust. A 10 percent specific propellant consumption improvement is possible with some seal modifications. It was demonstrated that APU power levels could be changed by several hundred horsepower in less than 100 msec without exceeding allowable turbine inlet temperatures or turbine speed.

  6. Confinement effects on the nuclear spin isomer conversion of H$_2$O

    Turgeon, Pierre-Alexandre; Alexandrowicz, Gil; Peperstraete, Yoann; Philippe, Laurent; Fillion, Jean-Hugues; Michaut, Xavier; Ayotte, Patrick


    The mechanism for interconversion between the nuclear spin isomers (NSI) of H$_2$O remains shrouded in uncertainties. The temperature dependence displayed by NSI interconversion rates for H$_2$O isolated in an Argon matrix provides evidence that confinement effects are responsible for the dramatic increase in their kinetics with respect to the gas phase, providing new pathways for o-H$_2$O $\\leftrightarrow$ p-H$_2$O conversion in endohedral compounds. This reveals intramolecular aspects of the interconversion mechanism which may improve methodologies for the separation and storage of NSI en route to applications in nuclear magnetic resonance spectroscopy and imaging. It may also improve astronomers' ability to use their relative abundance in the interstellar medium as proxies, thereby providing a valuable "astronomical clock".

  7. A shock tube study of OH + H(2)O(2) --> H(2)O + HO(2) and H(2)O(2) + M --> 2OH + M using laser absorption of H(2)O and OH.

    Hong, Zekai; Cook, Robert D; Davidson, David F; Hanson, Ronald K


    The rate constants of the reactions: (1) H2O2+M-->2OH+M, (2) OH+H2O2-->H2O+HO2 were measured in shock-heated H(2)O(2)/Ar mixtures using laser absorption diagnostics for H(2)O and OH. Time-histories of H(2)O were monitored using tunable diode laser absorption at 2550.96 nm, and time-histories of OH were achieved using ring dye laser absorption at 306 nm. Initial H(2)O(2) concentrations were also determined utilizing the H(2)O diagnostic. On the basis of simultaneous time-history measurements of OH and H(2)O, k(2) was found to be 4.6 x 10(13) exp(-2630 K/T) [cm(3) mol(-1) s(-1)] over the temperature range 1020-1460 K at 1.8 atm; additional measurements of k(2) near 1 atm showed no significant pressure dependence. Similarly, k(1) was found to be 9.5 x 10(15) exp(-21 250 K/T) [cm(3) mol(-1) s(-1)] over the same temperature and pressure range.

  8. H2O Formation in C-rich AGB Winds

    R. Lombaert; L. Decin; P. Royer; A. de Koter; N.L.J. Cox; J. De Ridder; T. Khouri; M. Agúndez; J.A.D.L. Blommaert; J. Gernicharo; E. González-Alfonso; M.A.T. Groenewegen; F. Kerschbaum; D. Neufeld; B. Vandenbussche; C. Waelkens


    The Herschel detection of warm H2O vapor emission from C-rich winds of AGB stars challenges the current understanding of circumstellar chemistry. Two mechanisms have been invoked to explain warm H2O formation. In the first, penetration of UV interstellar radiation through a clumpy circumstellar medi

  9. Scavenging of H2O2 by mouse brain mitochondria.

    Starkov, Anatoly A; Andreyev, Alexander Yu; Zhang, Steven F; Starkova, Natalia N; Korneeva, Maria; Syromyatnikov, Mikhail; Popov, Vasily N


    Mitochondrial reactive oxygen species (ROS) metabolism is unique in that mitochondria both generate and scavenge ROS. Recent estimates of ROS scavenging capacity of brain mitochondria are surprisingly high, ca. 9-12 nmol H2O2/min/mg, which is ~100 times higher than the rate of ROS generation. This raises a question whether brain mitochondria are a source or a sink of ROS. We studied the interaction between ROS generation and scavenging in mouse brain mitochondria by measuring the rate of removal of H2O2 added at a concentration of 0.4 μM, which is close to the reported physiological H2O2 concentrations in tissues, under conditions of low and high levels of mitochondrial H2O2 generation. With NAD-linked substrates, the rate of H2O2 generation by mitochondria was ~50-70 pmol/min/mg. The H2O2 scavenging dynamics was best approximated by the first order reaction equation. H2O2 scavenging was not affected by the uncoupling of mitochondria, phosphorylation of added ADP, or the genetic ablation of glutathione peroxidase 1, but decreased in the absence of respiratory substrates, in the presence of thioredoxin reductase inhibitor auranofin, or in partially disrupted mitochondria. With succinate, the rate of H2O2 generation was ~2,200-2,900 pmol/min/mg; the scavenging of added H2O2 was masked by a significant accumulation of generated H2O2 in the assay medium. The obtained data were fitted into a simple model that reasonably well described the interaction between H2O2 scavenging and production. It showed that mitochondria are neither a sink nor a source of H2O2, but can function as both at the same time, efficiently stabilizing exogenous H2O2 concentration at a level directly proportional to the ratio of the H2O2 generation rate to the rate constant of the first order scavenging reaction.

  10. Kinetics and mechanisms of reactions between H2O2 and copper and copper oxides.

    Björkbacka, Åsa; Yang, Miao; Gasparrini, Claudia; Leygraf, Christofer; Jonsson, Mats


    One of the main challenges for the nuclear power industry today is the disposal of spent nuclear fuel. One of the most developed methods for its long term storage is the Swedish KBS-3 concept where the spent fuel is sealed inside copper canisters and placed 500 meters down in the bedrock. Gamma radiation will penetrate the canisters and be absorbed by groundwater thereby creating oxidative radiolysis products such as hydrogen peroxide (H2O2) and hydroxyl radicals (HO˙). Both H2O2 and HO˙ are able to initiate corrosion of the copper canisters. In this work the kinetics and mechanism of reactions between the stable radiolysis product, H2O2, and copper and copper oxides were studied. Also the dissolution of copper into solution after reaction with H2O2 was monitored by ICP-OES. The experiments show that both H2O2 and HO˙ are present in the systems with copper and copper oxides. Nevertheless, these species do not appear to influence the dissolution of copper to the same extent as observed in recent studies in irradiated systems. This strongly suggests that aqueous radiolysis can only account for a very minor part of the observed radiation induced corrosion of copper.

  11. Pyruvate protects pathogenic spirochetes from H2O2 killing.

    Bryan Troxell

    Full Text Available Pathogenic spirochetes cause clinically relevant diseases in humans and animals, such as Lyme disease and leptospirosis. The causative agent of Lyme disease, Borrelia burgdorferi, and the causative agent of leptospirosis, Leptospria interrogans, encounter reactive oxygen species (ROS during their enzootic cycles. This report demonstrated that physiologically relevant concentrations of pyruvate, a potent H2O2 scavenger, and provided passive protection to B. burgdorferi and L. interrogans against H2O2. When extracellular pyruvate was absent, both spirochetes were sensitive to a low dose of H2O2 (≈0.6 µM per h generated by glucose oxidase (GOX. Despite encoding a functional catalase, L. interrogans was more sensitive than B. burgdorferi to H2O2 generated by GOX, which may be due to the inherent resistance of B. burgdorferi because of the virtual absence of intracellular iron. In B. burgdorferi, the nucleotide excision repair (NER and the DNA mismatch repair (MMR pathways were important for survival during H2O2 challenge since deletion of the uvrB or the mutS genes enhanced its sensitivity to H2O2 killing; however, the presence of pyruvate fully protected ΔuvrB and ΔmutS from H2O2 killing further demonstrating the importance of pyruvate in protection. These findings demonstrated that pyruvate, in addition to its classical role in central carbon metabolism, serves as an important H2O2 scavenger for pathogenic spirochetes. Furthermore, pyruvate reduced ROS generated by human neutrophils in response to the Toll-like receptor 2 (TLR2 agonist zymosan. In addition, pyruvate reduced neutrophil-derived ROS in response to B. burgdorferi, which also activates host expression through TLR2 signaling. Thus, pathogenic spirochetes may exploit the metabolite pyruvate, present in blood and tissues, to survive H2O2 generated by the host antibacterial response generated during infection.

  12. Estimating the maximum potential revenue for grid connected electricity storage :

    Byrne, Raymond Harry; Silva Monroy, Cesar Augusto.


    The valuation of an electricity storage device is based on the expected future cash flow generated by the device. Two potential sources of income for an electricity storage system are energy arbitrage and participation in the frequency regulation market. Energy arbitrage refers to purchasing (stor- ing) energy when electricity prices are low, and selling (discharging) energy when electricity prices are high. Frequency regulation is an ancillary service geared towards maintaining system frequency, and is typically procured by the independent system operator in some type of market. This paper outlines the calculations required to estimate the maximum potential revenue from participating in these two activities. First, a mathematical model is presented for the state of charge as a function of the storage device parameters and the quantities of electricity purchased/sold as well as the quantities o ered into the regulation market. Using this mathematical model, we present a linear programming optimization approach to calculating the maximum potential revenue from an elec- tricity storage device. The calculation of the maximum potential revenue is critical in developing an upper bound on the value of storage, as a benchmark for evaluating potential trading strate- gies, and a tool for capital nance risk assessment. Then, we use historical California Independent System Operator (CAISO) data from 2010-2011 to evaluate the maximum potential revenue from the Tehachapi wind energy storage project, an American Recovery and Reinvestment Act of 2009 (ARRA) energy storage demonstration project. We investigate the maximum potential revenue from two di erent scenarios: arbitrage only and arbitrage combined with the regulation market. Our analysis shows that participation in the regulation market produces four times the revenue compared to arbitrage in the CAISO market using 2010 and 2011 data. Then we evaluate several trading strategies to illustrate how they compare to the

  13. Solubility of ammonium paratungstate in the system NH3·H2O-H2O


    The equilibrium solubilities of 5(NH4)O@ 12WO3 @ 5H2O (APT@ 5H2O) were determined at the terminal ammoniaconcentration of 2 mol/L at 87-95℃. Experimental data were regressed. The linear functional relation between the solubilityof APT@ 5H2O and the temperature (t / ℃) is given as y = - 588.08 + 7.28t. The solubility of the species as a function of theterminal ammonia concentration (x / mol@ L-1) is also achieved: y = 36.76 + 18.86x. The solubility of APT@ 5H2O producedby ion-exchange method in China is much lower, which is due to much lower silica, much higher NH4C1, and a smallamount of APT@ 7H2O with low solubility in the APT crystals. APT@ 7H2O forms because of a large amount of NH4Cl andthe low activity of water in the crystallization.

  14. Magnetocaloric effect in gadolinium-oxalate framework Gd2(C2O43(H2O6⋅(0⋅6H2O

    Romain Sibille


    Full Text Available Magnetic refrigerants incorporating Gd3+ ions and light organic ligands offer a good balance between isolation of the magnetic centers and their density. We synthesized the framework material Gd2(C2O43(H2O6⋅0.6H2O by a hydrothermal route and characterized its structure. The honeycomb lattice of Gd3+ ions interlinked by oxalate ligands in the (a,c plane ensures their decoupling in terms of magnetic exchange interactions. This is corroborated by magnetic measurements indicating negligible interactions between the Gd3+ ions in this material. The magnetocaloric effect was evaluated from isothermal magnetization measurements. The maximum entropy change −ΔSMmax reaches 75.9 mJ cm−3 K−1 (around 2 K for a moderate field change (2 T.

  15. Destruction and Sequestration of H2O on Mars

    Clark, Benton


    The availability of water in biologically useable form on any planet is a quintessential resource, even if the planet is in a zone habitable with temperature regimes required for growth of organisms (above -18 °C). Mars and most other planetary objects in the solar system do not have sufficient liquid water at their surfaces that photosynthesis or chemolithoautotrophic metabolism could occur. Given clear evidence of hydrous mineral alteration and geomorphological constructs requiring abundant supplies of liquid water in the past, the question arises whether this H2O only became trapped physically as ice, or whether there could be other, more or less accessible reservoirs that it has evolved into. Salts containing S or Cl appear to be ubiquitous on Mars, having been measured in soils by all six Mars landed missions, and detected in additional areas by orbital investigations. Volcanoes emit gaseous H2S, S, SO2, HCl and Cl2. A variety of evidence indicates the geochemical fate of these gases is to be transformed into sulfates, chlorides, chlorates and perchlorates. Depending on the gas, the net reaction causes the destruction of between one and up to eight molecules of H2O per atom of S or Cl (although hydrogen atoms are also released, they are lost relatively rapidly to atmospheric escape). Furthermore, the salt minerals formed often incorporate H2O into their crystalline structures, and can result in the sequestration of up to yet another six (sometimes, more) molecules of H2O. In addition, if the salts are microcrystalline or amorphous, they are potent adsorbents for H2O. In certain cases, they are even deliquescent under martian conditions. Finally, the high solubility of the vast majority of these salts (with notable exception of CaSO4) can result in dense brines with low water activity, aH, as well as cations which can be inimical to microbial metabolism, effectively "poisoning the well." The original geologic materials on Mars, igneous rocks, also provide some

  16. CO diffusion into amorphous H2O ices

    Lauck, Trish; Shulenberger, Katherine; Rajappan, Mahesh; Oberg, Karin I; Cuppen, Herma M


    The mobility of atoms, molecules and radicals in icy grain mantles regulate ice restructuring, desorption, and chemistry in astrophysical environments. Interstellar ices are dominated by H2O, and diffusion on external and internal (pore) surfaces of H2O-rich ices is therefore a key process to constrain. This study aims to quantify the diffusion kinetics and barrier of the abundant ice constituent CO into H2O dominated ices at low temperatures (15-23 K), by measuring the mixing rate of initially layered H2O(:CO2)/CO ices. The mixed fraction of CO as a function of time is determined by monitoring the shape of the infrared CO stretching band. Mixing is observed at all investigated temperatures on minute time scales, and can be ascribed to CO diffusion in H2O ice pores. The diffusion coefficient and final mixed fraction depend on ice temperature, porosity, thickness and composition. The experiments are analyzed by applying Fick's diffusion equation under the assumption that mixing is due to CO diffusion into an i...

  17. A Global PLASIMO Model for H2O Chemistry

    Tadayon Mousavi, Samaneh; Koelman, Peter; Graef, Wouter; Mihailova, Diana; van Dijk, Jan; EPG/ Applied Physics/ Eindhoven University of Technology Team; Plasma Matters B. V. Team


    Global warming is one of the critical contemporary problems for mankind. Transformation of CO2 into fuels, like CH4, that are transportable with the current infrastructure seems a promising idea to solve this threatening issue. The final aim of this research is to produce CH4 by using microwave plasma in CO2 -H2 O mixture and follow-up catalytic processes. In this contribution we present a global model for H2 O chemistry that is based on the PLASIMO plasma modeling toolkit. The time variation of the electron energy and the species' densities are calculated based on the source and loss terms in plasma due to chemical reactions. The short simulation times of such models allow an efficient assessment and chemical reduction of the H2O chemistry, which is required for full spatially resolved simulations.

  18. [Efficiency of atrazine degradation by O3/H2O2].

    Li, Shao-Feng; Liang, Yuan; Zhang, Rong-Quan; Ye, Fei


    The endocrine disrupter Atrazine was oxidized by O3/H2O2 system and the products were analyzed to assess the degradation efficiency of Atrazine. When it's initial content was 2 mg/L and O3 dosage was 7.5 mg/L, Atrazine was removed about 27.2% after 5 minutes. Under the same condition, H2O2/O3 molar ratio was 0.75, Atrazine maximum removal rate reached 96.5%, which suggested that Atrazine could be degraded by O3/H2O2 system effectively. Ion Chromatography (IC) analysis showed that concentrations of chloride and nitrate ions were increasing along with the Atrazine content decreasing. Gas Chromatography-Mass spectrometry (GC-MS) and Liquid Chromatography-Mass spectrometry chromatograms (LC-MS) analyzing illuminated the existence of de-ethyl-atrazine, de-isopropyl-atrazine and de-chloro-atrazine, which indicated the Atrazine could not be destroyed completely by O3/H2O2 system. Consequently, it should be combined with GAC (Granular Activated Carbon) or other techniques while used as primary treatment unit or emergency measure.

  19. Removal of sulfamethoxazole and diclofenac from water: strategies involving O3 and H2O2.

    Gomes, Daniela S; Gando-Ferreira, Licínio M; Quinta-Ferreira, Rosa M; Martins, Rui C


    Diclofenac (DCF) and Sulfamethoxazole (SMX) are two of the most frequently detected pharmaceutical compounds in water and are hardly removed by biological treatment systems. The presence of H2O2 was investigated in the ozonation of these two compounds. Experiments were carried out with both using distilled water and secondary effluent from a municipal wastewater treatment plant spiked with pharmaceuticals. Chemical oxygen demand (COD) abatement rate improved when H2O2 was added at the beginning of the ozonation process and when the ozone inlet concentration increased, attaining a maximum value of 91% and simultaneously a lower ozone waste for a H2O2 initial concentration of 5 mM and an ozone inlet concentration of 20 g Nm(-3). For these operation conditions, the water matrix has no significant impact on SMX and DCF removal, which were totally degraded in 45 and 60 min, respectively. Nevertheless, lower COD degradation and ozone usage were obtained when the secondary effluent was used. Inorganic ions such as chloride, sulphate and nitrate and short-chain organic compounds were detected as by-products of the SMX and DCF oxidation. Vibrio fischeri luminescence inhibition tests revealed that simultaneous use of ozone and H2O2 reduced acute toxicity.

  20. Experimental studies of the formation of cluster ions formed by corona discharge in an atmosphere containing SO2, NH3, and H2O

    Pedersen, J. O.; Hvelplund, P.; Støchkel, K.; Enghoff, M. B.; Kurten, T.


    We report on studies of ion induced nucleation in a corona discharge taking place in an atmosphere containing SO2, NH3, and H2O at standard temperature and pressure. Positive ions such as H3O+(H2O)n, NH4+(H2O)n, and H+(H2SO4)(H2O)n and negative ions such as HSO5-(H2O)n, SO4-(H2O)n, HSO4-(H2O)n and NO3-(H2O)n have been recorded. Large values of n (> 100) were observed and the experiment indicates the existence of even larger water clusters. In contrast, only clusters with a maximum of 2 sulfuric acid molecules were observed. Fragmentation studies also revealed that the negative ion HSO5-, which has been observed in many studies, in our experiments is contaminated by O2-(HNO3)(H2O) ions, and this may also have been the case in other experiments. Finally an ion with m/z = 232 (where m is the cluster mass in amu and z the charge state), capable of attaching H2O-molecules was observed and studied by fragmentation. Positive ion m/z (mass/charge) spectrum

  1. Efficiency of Atrazine Degradation by O3 /H2O2%O3/H2O2降解Atrazine效能研究

    李绍峰; 梁媛; 张荣全; 叶非


    The endocrine disrupter Atrazine was oxidized by O3/H2O2 system and the products were analyzed to assess the degradation efficiency of Atrazine.When it's initial content was 2 mg/L and O3 dosage was 7.5 mg/L,Atrazine was removed about 27.2% after 5 minutes.Under the same condition,H2O2/O3 molar ratio was 0.75,Atrazine maximum removal rate reached 96.5%,which suggested that Atrazine could be degraded by O3/H2O2 system effectively.Ion Chromatography(IC) analysis showed that concentrations of chloride and nitrate ions were increasing along with the Atrazine content decreasing.Gas Chromatography-Mass spectrometry (GC-MS) and Liquid Chromatography-Mass spectrometry chromatograms (LC-MS) analyzing illuminated the existence of de-ethyl-atrazine,de-isopropyl-atrazine and de-chloro-atrazine,which indicated the Atrazine could not be destroyed completely by O3/H2O2 system.Consequently,it should be combined with GAC (Granular Activated Carbon) or other techniques while used as primary treatment unit or emergency measure.%利用O3/H2O2降解莠去津,对氧化产物进行了色谱分析,以评价该体系降解莠去津效能.莠去津初始浓度2 mg/L,7.5 mg/L的O3单独氧化去除率为27.2%;相同O3投量下,H2O2/O3摩尔比0.75时,5 min莠去津的去除率最高可达96.5%,表明H2O2/O3体系对莠去津的去除效果良好,降解速度快.以离子色谱对产物的离子进行分析,莠去津浓度下降的同时,硝酸根和氯离子浓度增高.GC-MS检测的产物和对LC-MS谱图的分析表明,有机产物中存在脱乙基、脱异丙基和脱氯莠去津,说明H2O2/O3并不能彻底氧化莠去津,因此工程中作为主要去除单元或突发性污染事件的应急手段可能还需要与活性炭等单元联用.

  2. Low energy spin dynamics of a quantum ferrimagnetic chain, NiCu(pba)(H 2O) 32H 2O

    Fujiwara, N.; Hagiwara, M.


    Nuclear magnetic resonance (NMR) for 1H nuclei was performed in a Heisenberg chain with alternating spins S=1 and 1/2, NiCu(pba)(H 2O) 32H 2O (pba=1,3-propylenebis (oxamato)) from 4.2 to 280 K. The relaxation rate (1/ T1) is proportional to 1/ H ( H is applied field), whereas the temperature dependence is weak and is almost constant at high temperatures. The temperature and field dependences are investigated on the basis of the spin-wave theory.

  3. Bolometric Luminosity Correction of H2O Maser AGNs

    Q. Guo; J. S. Zhang; J. Wang


    For the H2O maser host AGN sample, we derived their bolometric luminosity corrections, based on their X-ray data and [O III] emission line luminosities. Our results for maser AGNs is comparable to that of non-maser AGNs.

  4. Intermolecular Interactions in Ternary Glycerol–Sample–H2O

    Westh, Peter; Rasmussen, Erik Lumby; Koga, Yoshikata


    We studied the intermolecular interactions in ternary glycerol (Gly)–sample (S)–H2O systems at 25 °C. By measuring the excess partial molar enthalpy of Gly, HGlyEHEGly, we evaluated the Gly–Gly enthalpic interaction, HGly-GlyEHEGly--Gly, in the presence of various samples (S). For S, tert...

  5. Odin observations of H2O in the Galactic Centre

    Sandqvist, A; Black, J; Sandqvist, Aa.


    The Odin satellite has been used to detect emission and absorption in the 557-GHz H2O line in the Galactic Centre towards the Sgr A* Circumnuclear Disk (CND), and the Sgr A +20 km/s and +50 km/s molecular clouds. Strong broad H2O emission lines have been detected in all three objects. Narrow H2O absorption lines are present at all three positions and originate along the lines of sight in the 3-kpc Spiral Arm, the -30 km/s Spiral Arm and the Local Sgr Spiral Arm. Broad H2O absorption lines near -130 km/s are also observed, originating in the Expanding Molecular Ring. A new molecular feature (the ``High Positive Velocity Gas'' - HPVG) has been identified in the positive velocity range of ~ +120 to +220 km/s, seen definitely in absorption against the stronger dust continuum emission from the +20 km/s and +50 km/s clouds and possibly in emission towards the position of Sgr A* CND. The 548-GHz H2_18O isotope line towards the CND is not detected at the 0.02 K (rms) level.

  6. Reaction of ferric leghemoglobin with H2O2

    Moreau, S; Davies, M J; Puppo, A


    Ferric leghemoglobin in the presence of H2O2 is known to give rise to protein radicals, at least one of which is centred on a tyrosine residue. These radicals are quenched by at least two processes. The first one involves an intramolecular heme-protein cross-link probably involving the tyrosine...

  7. Tricyclic sesquiterpene copaene prevents H2O2-induced neurotoxicity

    Hasan Turkez


    Full Text Available Aim: Copaene (COP, a tricyclic sesquiterpene, is present in several essential oils of medicinal and aromatic plants and has antioxidant and anticarcinogenic features. But, very little information is known about the effects of COP on oxidative stress induced neurotoxicity. Method: We used hydrogen peroxide (H2O2 exposure for 6 h to model oxidative stress. Therefore, this experimental design allowed us to explore the neuroprotective potential of COP in H2O2-induced toxicity in rat cerebral cortex cell cultures for the first time. For this purpose, methyl thiazolyl tetrazolium (MTT and lactate dehydrogenase (LDH release assays were carried out to evaluate cytotoxicity. Total antioxidant capacity (TAC and total oxidative stress (TOS parameters were used to evaluate oxidative changes. In addition to determining of 8-hydroxy-2-deoxyguanosine (8-OH-dG levels, the single cell gel electrophoresis (SCGE or comet assay was also performed for measuring the resistance of neuronal DNA to H2O2-induced challenge. Result: The results of this study showed that survival and TAC levels of the cells decreased, while TOS, 8-OH-dG levels and the mean values of the total scores of cells showing DNA damage increased in the H2O2 alone treated cultures. But pre-treatment of COP suppressed the cytotoxicity, genotoxicity and oxidative stress which were increased by H2O2. Conclusion: It is proposed that COP as a natural product with an antioxidant capacity in mitigating oxidative injuries in the field of neurodegenerative diseases. [J Intercult Ethnopharmacol 2014; 3(1.000: 21-28

  8. Relaxation phenomena in CsCoCl3·2 H2O

    Flokstra, J.; Gerritsma, G.J.; Vermeulen, A.J.W.A; Botterman, A.C.


    Dynamic susceptibility measurements have been performed on a single crystal of CsCoCl3·2H2O at liquid temperatures by means of a Hartshorn mutual inductance bridge. At the magnetic phase transition a maximum in τabs(H) has been observed. A jump in τabs(T) has been found at the λ-point of liquid heli

  9. Kinetic Model for UV/H2O2 Degradation of 5-Methoxypsoralen

    Tchaikovskaya, O. N.; Bryantseva, N. G.; Carrasco, J. L. Gómez; Krayukhina, V. S.; Almagro, M. D. Murcia; Gómez, M. Gómez


    The influence of H2O2 on the photodegradataion of 5-methoxypsoralen (5-MOP) in ethanol and in waterethanol solutions upon exposure to KrCl excilamp radiation (λrad = 222 nm) and XeBr excilamp radiation (λrad = 283 nm) is investigated. A kinematic model of photodegradation of the investigated molecule is constructed. The addition of H2O2 resulted in a weak increase of the decay rate of 5-MOP in ethanol exposed to KrCl excilamp radiation. In water-ethanol solutions the addition of H2O2 altered the mechanism of decay of 5-MOP irradiated by the KrCl excilamp in comparison with irradiation by the XeBr excilamp. It has been shown that upon exposure to XeBr excilamp radiation in the presence of H2O2, the primary photoproduct of the transformation of 5-MOP in the reaction corresponding to the first-order kinetic model is formed both in ethanol and in the water-ethanol solutions. Maximum removal of 5-MOP takes place for the ratio of initial concentrations [5-MOP]:[H2O2] = 1:3 after 60 min irradiation. It is found that irradiation by the XeBr excilamp the decay rate of 5-MOP is 5 times higher in the water-ethanol solutions in comparison with ethanol. Upon exposure to KrCl excilamp radiation the mechanism of 5-MOP decay corresponds to a pseudo-firstorder kinetic model. The nature of the dependence of the decay rate of 5-MOP on the irradiation time for the ratio of initial concentrations [5-MOP]:[H2O2] = 1:24 indicates that during decay of the initial compound a photoproduct appears in the system which decays during the irradiation time into secondary compounds. Efficient removal of 5-MOP under this irradiation takes place for the ratio of initial concentrations [5-MOP]:[H2O2] = 1:10 after 60 min irradiation.

  10. Photoassisted Oxygen Reduction Reaction in H2 -O2 Fuel Cells.

    Zhang, Bingqing; Wang, Shengyang; Fan, Wenjun; Ma, Weiguang; Liang, Zhenxing; Shi, Jingying; Liao, Shijun; Li, Can


    The oxygen reduction reaction (ORR) is a key step in H2 -O2 fuel cells, which, however, suffers from slow kinetics even for state-of-the-art catalysts. In this work, by making use of photocatalysis, the ORR was significantly accelerated with a polymer semiconductor (polyterthiophene). The onset potential underwent a positive shift from 0.66 to 1.34 V, and the current was enhanced by a factor of 44 at 0.6 V. The improvement was further confirmed in a proof-of-concept light-driven H2 -O2 fuel cell, in which the open circuit voltage (Voc ) increased from 0.64 to 1.18 V, and the short circuit current (Jsc ) was doubled. This novel tandem structure combining a polymer solar cell and a fuel cell enables the simultaneous utilization of photo- and electrochemical energy, showing promising potential for applications in energy conversion and storage.

  11. Vibrational investigations of CO2-H2O, CO2-(H2O)2, and (CO2)2-H2O complexes isolated in solid neon

    Soulard, P.; Tremblay, B.


    The van der Waals complex of H2O with CO2 has attracted considerable theoretical interest as a typical example of a weak binding complex with a dissociation energy less than 3 kcal/mol. Up to now, experimental vibrational data are sparse. We have studied by FTIR the complexes involving CO2 and water molecules in solid neon. Many new absorption bands close to the well known monomers fundamentals give evidence for at least three (CO2)n-(H2O)m complexes, noted n:m. Concentration effects combined with a detailed vibrational analysis allow for the identification of sixteen, twelve, and five transitions for the 1:1, 1:2, and 2:1 complexes, respectively. Careful examination of the far infrared spectral region allows the assignment of several 1:1 and 1:2 intermolecular modes, confirmed by the observation of combinations of intra + intermolecular transitions, and anharmonic coupling constants have been derived. Our results demonstrate the high sensibility of the solid neon isolation to investigate the hydrogen-bonded complexes in contrast with the gas phase experiments for which two quanta transitions cannot be easily observed.

  12. Vibrational investigations of CO2-H2O, CO2-(H2O)2, and (CO2)2-H2O complexes isolated in solid neon.

    Soulard, P; Tremblay, B


    The van der Waals complex of H2O with CO2 has attracted considerable theoretical interest as a typical example of a weak binding complex with a dissociation energy less than 3 kcal/mol. Up to now, experimental vibrational data are sparse. We have studied by FTIR the complexes involving CO2 and water molecules in solid neon. Many new absorption bands close to the well known monomers fundamentals give evidence for at least three (CO2)n-(H2O)m complexes, noted n:m. Concentration effects combined with a detailed vibrational analysis allow for the identification of sixteen, twelve, and five transitions for the 1:1, 1:2, and 2:1 complexes, respectively. Careful examination of the far infrared spectral region allows the assignment of several 1:1 and 1:2 intermolecular modes, confirmed by the observation of combinations of intra + intermolecular transitions, and anharmonic coupling constants have been derived. Our results demonstrate the high sensibility of the solid neon isolation to investigate the hydrogen-bonded complexes in contrast with the gas phase experiments for which two quanta transitions cannot be easily observed.

  13. Oxidative degradation of endotoxin by advanced oxidation process (O3/H2O2 & UV/H2O2).

    Oh, Byung-Taek; Seo, Young-Suk; Sudhakar, Dega; Choe, Ji-Hyun; Lee, Sang-Myeong; Park, Youn-Jong; Cho, Min


    The presence of endotoxin in water environments may pose a serious public health hazard. We investigated the effectiveness of advanced oxidative processes (AOP: O3/H2O2 and UV/H2O2) in the oxidative degradation of endotoxin. In addition, we measured the release of endotoxin from Escherichia coli following typical disinfection methods, such as chlorine, ozone alone and UV, and compared it with the use of AOPs. Finally, we tested the AOP-treated samples in their ability to induce tumor necrosis factor alpha (TNF-α) in mouse peritoneal macrophages. The production of hydroxyl radical in AOPs showed superior ability to degrade endotoxin in buffered solution, as well as water samples from Korean water treatment facilities, with the ozone/H2O2 being more efficient compared to UV/H2O2. In addition, the AOPs proved effective not only in eliminating E. coli in the samples, but also in endotoxin degradation, while the standard disinfection methods lead to the release of endotoxin following the bacteria destruction. Furthermore, in the experiments with macrophages, the AOPs-deactivated endotoxin lead to the smallest induction of TNF-α, which shows the loss of inflammation activity, compared to ozone treatment alone. In conclusion, these results suggest that AOPs offer an effective and mild method for endotoxin degradation in the water systems.

  14. Optimization of H2O2 dosage in microwave-H2O2 process for sludge pretreatment with uniform design method

    Qingcong Xiao; Hong Yan; Yuansong Wei; Yawei Wang; Fangang Zeng; Xiang Zheng


    A microwave-H2O2 process for sludge pretreatment exhibited high efficiencies of releasing organics,nitrogen,and phosphorus,but large quantities of H2O2 residues were detected.A uniform design method was thus employed in this study to further optimize H2O2 dosage by investigating effects of pH and H2O2 dosage on the amount of H2O2 residue and releases of organics,nitrogen,and phosphorus.A regression model was established with pH and H2O2 dosage as the independent variables,and H2O2 residue and releases of organics,nitrogen,and phosphorus as the dependent variables.In the optimized microwave-H2O2 process,the pH value of the sludge was firstly adjusted to 11.0,then the sludge was heated to 80C and H2O2 was dosed at a H2O2:mixed liquor suspended solids (MLSS) ratio of 0.2,and the sludge was finally heated to 100℃ by microwave irradiation.Compared to the microwave-H2O2 process without optimization,the H2O2 dosage and the utilization rate of H2O2 in the optimized microwave-H2O2 process were reduced by 80% and greatly improved by 3.87 times,respectively,when the H2O2:MLSS dosage ratio was decreased from 1.0 to 0.2,resulting in nearly the same release rate of soluble chemical oxygen demand in the microwave-H2O2 process without optimization at H2O2:MLSS ratio of 0.5.

  15. Degradation and antibiotic activity reduction of chloramphenicol in aqueous solution by UV/H2O2 process.

    Zuorro, Antonio; Fidaleo, Marco; Fidaleo, Marcello; Lavecchia, Roberto


    The efficacy of the UV/H2O2 process to degrade the antibiotic chloramphenicol (CHL) was investigated at 20 °C using a low-pressure mercury lamp as UV source. A preliminary analysis of CHL degradation showed that the process followed apparent first-order kinetics and that an optimum H2O2 concentration existed for the degradation rate. The first-order rate constant was used as the response variable and its dependence on initial CHL and H2O2 concentrations, UV light intensity and reaction time was investigated by a central composite design based on the response surface methodology. Analysis of response surface plots revealed a large positive effect of radiation intensity, a negative effect of CHL concentration and that there was a region of H2O2 concentration leading to maximum CHL degradation. CHL solutions submitted to the UV/H2O2 process were characterized by TOC and their activity against Escherichia coli and Staphylococcus aureus was assessed. No residual antibiotic activity was detected, even at CHL concentrations higher than those used in the designed experiments. Overall, the obtained results strongly support the possibility of reducing the risks associated with the release of CHL into the environment, including the spread of antibiotic resistance, by the UV/H2O2 process.

  16. Oxidative degradation of dyes in water using Co2+/H2O2 and Co2+/peroxymonosulfate.

    Ling, Sie King; Wang, Shaobin; Peng, Yuelian


    Dye degradation using advanced oxidation processes with Co(2+)/H(2)O(2) and Co(2+)/peroxymonosulfate (PMS) systems has been investigated. Two types of dyes, basic blue 9 and acid red 183, were employed. Several parameters affecting dye degradation such as Co(2+), PMS, H(2)O(2), and dye concentrations were investigated. The optimal ratio of oxidant (PMS, H(2)O(2))/Co(2+) for the degradation of two dyes was determined. It is found that dye decomposition is much faster in Co(2+)/PMS system than in Co(2+)/H(2)O(2). For Co(2+)/H(2)O(2), an optimal ratio of H(2)O(2) to Co(2+) at 6 is required for the maximum decomposition of the dyes. For Co(2+)/PMS, higher concentrations of Co(2+) and PMS will increase dye degradation rate with an optimal ratio of 3, achieving 95% decolourisation. For basic blue 9, a complete decolourisation can be achieved in 5 min at 0.13 mM Co(2+), 0.40 mM PMS and 7 mg/l basic blue 9 while the complete degradation of acid red 183 will be achieved at 30 min at 0.13 mM Co(2+), 0.40 mM PMS and 160 mg/l of acid red 183. The degradation of acid red 183 follows the second-order kinetics. Copyright 2010 Elsevier B.V. All rights reserved.

  17. Enhancement effect of trace H2O on the charge-discharge cycling performance of a Li metal anode

    Togasaki, Norihiro; Momma, Toshiyuki; Osaka, Tetsuya


    The effects of a small amount of H2O with and without CO2 in an electrolyte of 1 M LiPF6/ethylene carbonate and diethyl carbonate on the cycling life of a Li metal anode is investigated in this paper using charge-discharge cycling. A low cycling performance, which is less than 55%, is observed with the electrolyte with trace H2O but without CO2; however, when the trace H2O is accompanied by CO2, performance drastically improves and coulombic efficiency reaches a maximum of 88.9%. In the presence of CO2, the cycling performance is found to be strongly affected by the H2O content in the electrolyte, and increases with an increase in H2O content of up to 35 ppm. From an X-ray photoelectron spectroscopy analysis, trace H2O is found to affect the compounds of the solid electrolyte interphase (SEI) on the lithium surface and produces an Li2CO3 and LiF layer on the upper part of the SEI, both known to be good passivation layers for preventing side reactions during charge-discharge cycling.

  18. Proton ordering dynamics of H2O ice

    Yen, Fei


    From high precision measurements of the complex dielectric constant of H2O ice, we identify the critical temperatures of the phase transition into and out of ice XI from ice Ih to occur at T_Ih-IX=58.9 K and T_IX-Ih=73.4 K. For D2O, T_Ih-IX=63.7 K and T_IX-Ih=78.2 K. A triple point is identified to exist at 0.07 GPa and 73.4 K for H2O and 0.08 GPa and 78.2 K for D2O where ices Ih, II and XI coexist. A first order phase transition with kinetic broadening associated to proton ordering dynamics is identified at 100 K.

  19. Ultrafast Librational Relaxation of H2O in Liquid Water

    Petersen, Jakob; Møller, Klaus Braagaard; Rey, Rossend


    The ultrafast librational (hindered rotational) relaxation of a rotationally excited H2O molecule in pure liquid water is investigated by means of classical nonequilibrium molecular dynamics simulations and a power and work analysis. This analysis allows the mechanism of the energy transfer from...... the excited H2O to its water neighbors, which occurs on a sub-100 fs time scale, to be followed in molecular detail, i.e., to determine which water molecules receive the energy and in which degrees of freedom. It is found that the dominant energy flow is to the four hydrogen-bonded water partners in the first...... hydration shell, dominated by those partners’ rotational motion, in a fairly symmetric fashion over the hydration shell. The minority component of the energy transfer, to these neighboring waters’ translational motion, exhibits an asymmetry in energy reception between hydrogen-bond-donating and -accepting...

  20. Preparation and H2O2 oxidation of extract

    Tian Yujiao; Qin Zhihong; Li Baomin


    Tongting coal (TTC) was exhaustively extracted with carbon disulfide and/N/-melthy-2-pyrolidinone (CS2/NMP) mixed solvents to afford brown particles of extract,which was characterized with proximate analyzer,transmission electron microscope (TEM) and Fourier transform infrared (FTIR) spectrometer.The results show that the nanometer particles of extract,which were free of ash,are superfine and superclean with tract content of 0.02% Ad and particles size of about 100-150 nm.TTC and extract were then subject to oxidation with H2O2 and oxidation products were subsequently analyzed with FTIR and gas chromatography/mass spectrometer (GC/MS).The results show that extract is more reactive with H2O2 in comparison to TTC and richer in oxygen-containing species including phenols,alcohols,ethers,esters,carboxylic acids and anhydrides.

  1. H2O diffusion in Mount Changbai peralkaline rhyolitic melt

    Zhang, Y.; Xu, Z.; Wang, H.; Behrens, H.


    For quantitative modeling of bubble growth and volcanic eruption dynamics, it is necessary to know H2O diffusivity in the melt. Mount Changbai Volcano at the border of China and North Korea has produced explosive peralkaline rhyolitic eruptions, including a 30-km3 eruption with an age of 1 ky (Horn and Schmincke, 2000). H2O diffusivity is expected to be greater in a peralkaline rhyolitic melt than a calc-alkaline rhyolitic melt. We have experimentally investigated H2O diffusion in Mount Changbai peralkaline rhyolite. Because phenocryst-free glass is not available from Mount Changbai eruption products, the starting materials (nominally dry and hydrous) are synthesized. The diffusion couple technique, with one half dry and the other half wet, is adopted. Three high- temperature experiments have been carried out at 500 MPa and one at 1500 MPa in a piston-cylinder apparatus. After the experiment, the sample is prepared into a doubly-polished section of about 0.2 mm thickness, which is analyzed by a Perkin-Elmer FTIR microscope. The data are fit following the procedures of Zhang and Behrens (2000) and Ni and Zhang (2008). Preliminary data show that H2O diffusivity in peralkaline rhyolitic melt is greater than that in calc-alkaline rhyolitic melt (Zhang and Behrens, 2000), as expected. The exact difference depends on temperature and pressure, and the ratio of diffusivity in the peralkaline rhyolitic melt to that in the calc-alkaline rhyolitic melt ranges from 1 to 3. More experiments will be conducted on this melt to provide the basic data for specific modeling of bubble growth and volcanic eruption dynamics in past and future Mount Changbai eruptions and other peralkaline rhyolitic eruptions. References: Horn S and Schmincke H U (2000) Bull. Volcanol., 61, 537. Ni H and Zhang Y (2008) Chem. Geol., doi: 10.1016/j.chemgeo.2008.01.011. Zhang Y and Behrens H (2000) Chem. Geol., 169, 243.

  2. Solar kerosene from H2O and CO2

    Furler, P.; Marxer, D.; Scheffe, J.; Reinalda, D.; Geerlings, H.; Falter, C.; Batteiger, V.; Sizmann, A.; Steinfeld, A.


    The entire production chain for renewable kerosene obtained directly from sunlight, H2O, and CO2 is experimentally demonstrated. The key component of the production process is a high-temperature solar reactor containing a reticulated porous ceramic (RPC) structure made of ceria, which enables the splitting of H2O and CO2 via a 2-step thermochemical redox cycle. In the 1st reduction step, ceria is endo-thermally reduced using concentrated solar radiation as the energy source of process heat. In the 2nd oxidation step, nonstoichiometric ceria reacts with H2O and CO2 to form H2 and CO - syngas - which is finally converted into kerosene by the Fischer-Tropsch process. The RPC featured dual-scale porosity for enhanced heat and mass transfer: mm-size pores for volumetric radiation absorption during the reduction step and μm-size pores within its struts for fast kinetics during the oxidation step. We report on the engineering design of the solar reactor and the experimental demonstration of over 290 consecutive redox cycles for producing high-quality syngas suitable for the processing of liquid hydrocarbon fuels.

  3. Interstellar H$_2$O Masers from J Shocks

    Hollenbach, David; McKee, Christopher F


    We present a model in which the 22 GHz H$_2$O masers observed in star-forming regions occur behind shocks propagating in dense regions (preshock density $n_0 \\sim 10^6 - 10^8$ cm$^{-3}$). We focus on high-velocity ($v_s > 30$ km s$^{-1}$) dissociative J shocks in which the heat of H$_2$ re-formation maintains a large column of $\\sim 300-400$ K gas; at these temperatures the chemistry drives a considerable fraction of the oxygen not in CO to form H$_2$O. The H$_2$O column densities, the hydrogen densities, and the warm temperatures produced by these shocks are sufficiently high to enable powerful maser action. The observed brightness temperatures (generally $\\sim 10^{11} - 10^{14}$ K) are the result of coherent velocity regions that have dimensions in the shock plane that are 10 to 100 times the shock thickness of $\\sim 10^{13}$ cm. The masers are therefore beamed towards the observer, who typically views the shock "edge-on", or perpendicular to the shock velocity; the brightest masers are then observed with t...

  4. Synthesis and Crystal Structure of [{Cd(hmbdc)(H2O)3}·2H2O]n

    HU Yue-Hua; WANG Yan; WANG Zuo-Wei; LI Yi-Zhi; ZHENG He-Gen


    A novel coordination polymer [{Cd(hmbdc)(H2O)3}·2H2O]n (hmbdc=5-hydroxy- isophthalic acid) has been synthesized and characterized by elemental analysis, IR spectra and single-crystal X-ray diffraction. The crystal belongs to monoclinic, space group P21/c, with a=9.599(3), b=18.699(5), c=7.557(2) (A), β= 108.198(4)°, V=1288.6(6) (A)3, Z=4, Mr=382.60, Dc=1.972 g/cm3, F(000)=760, μ=1.740, the final R=0.0555 and wR=0.0995 for 1732 observed reflections with Ⅰ > 2σ(Ⅰ). The structural analysis shows that the intermolecular hydrogen bonds and π-π interactions result in a three-dimensional supramolecular framework.

  5. Kinetics of HO2 + HO2 -> H2O2 + O2: Implications for Stratospheric H2O2

    Christensen, L. E.; Okumura, M.; Sander, S. P.; Salawitch, R. J.; Toon, G. C.; Sen, B.; Blavier, J.-F.; Jucks, K. W.


    The reaction HO2 + HO2 -> H2O2 + O2refid="df01" type="formula">(1) has been studied at 100 Torr and 222 K to 295 K. Experiments employing photolysis of Cl2/CH3OH/O2/N2 and F2/H2/O2/N2 gas mixtures to produce HO2 confirmed that methanol enhanced the observed reaction rate. At 100 Torr, zero methanol, k1 = (8.8 +/- 0.9) 10-13 × exp[(210 +/- 26)/T] cm3 molecule-1 s-1 (2σ uncertainties), which agrees with current recommendations at 295 K but is nearly 2 times slower at 231 K. The general expression for k1, which includes the dependence on bath gas density, is k1 = (1.5 +/- 0.2) × 10-12 × exp[(19 +/- 31)/T] + 1.7 × 10-33 × [M] × exp[1000/T], where the second term is taken from the JPL00-3 recommendation. The revised rate largely accounts for a discrepancy between modeled and measured [H2O2] in the lower to middle stratosphere.

  6. On the Maximum Storage Capacity of the Hopfield Model

    Folli, Viola; Leonetti, Marco; Ruocco, Giancarlo


    Recurrent neural networks (RNN) have traditionally been of great interest for their capacity to store memories. In past years, several works have been devoted to determine the maximum storage capacity of RNN, especially for the case of the Hopfield network, the most popular kind of RNN. Analyzing the thermodynamic limit of the statistical properties of the Hamiltonian corresponding to the Hopfield neural network, it has been shown in the literature that the retrieval errors diverge when the number of stored memory patterns (P) exceeds a fraction (≈ 14%) of the network size N. In this paper, we study the storage performance of a generalized Hopfield model, where the diagonal elements of the connection matrix are allowed to be different from zero. We investigate this model at finite N. We give an analytical expression for the number of retrieval errors and show that, by increasing the number of stored patterns over a certain threshold, the errors start to decrease and reach values below unit for P ≫ N. We demonstrate that the strongest trade-off between efficiency and effectiveness relies on the number of patterns (P) that are stored in the network by appropriately fixing the connection weights. When P≫N and the diagonal elements of the adjacency matrix are not forced to be zero, the optimal storage capacity is obtained with a number of stored memories much larger than previously reported. This theory paves the way to the design of RNN with high storage capacity and able to retrieve the desired pattern without distortions. PMID:28119595

  7. H2O2 assisted room temperature oxidation of Ti2C MXene for Li-ion battery anodes

    Ahmed, Bilal


    Herein we demonstrate that a prominent member of the MXene family, Ti2C, undergoes surface oxidation at room temperature when treated with hydrogen peroxide (H2O2). The H2O2 treatment results in opening up of MXene sheets and formation of TiO2 nanocrystals on their surface, which is evidenced by the high surface area of H2O2 treated MXene and X-ray diffraction (XRD) analysis. We show that the reaction time and the amount of hydrogen peroxide used are the limiting factors, which determine the morphology and composition of the final product. Furthermore, it is shown that the performance of H2O2 treated MXene as an anode material in Li ion batteries (LIBs) was significantly improved as compared to as-prepared MXenes. For instance, after 50 charge/discharge cycles, specific discharge capacities of 389 mA h g−1, 337 mA h g−1 and 297 mA h g−1 were obtained for H2O2 treated MXene at current densities of 100 mA g−1, 500 mA g−1 and 1000 mA g−1, respectively. In addition, when tested at a very high current density, such as 5000 mA g−1, the H2O2 treated MXene showed a specific capacity of 150 mA h g−1 and excellent rate capability. These results clearly demonstrate that H2O2 treatment of Ti2C MXene improves MXene properties in energy storage applications, such as Li ion batteries or capacitors.

  8. Microwave-assisted pretreatment of woody biomass with ammonium molybdate activated by H2O2.

    Verma, Pradeep; Watanabe, Takahito; Honda, Yoichi; Watanabe, Takashi


    Pretreatments for enzymatic saccharification are crucial for the establishment of lignocellulosic biorefineries. In this study, we focused on ammonium ions and peroxometal complexes as potential delignifying agents. We first examined the pretreatment of beech wood with nine different ammonium salts in the presence of H(2)O(2). Significant pretreatment effects were found only for ammonium molybdate, which is transformed to a peroxometal complex on reacting with H(2)O(2). Since microwave sensitizer effects are expected for (peroxo)molybdate, beech wood was pretreated using external heating and microwave irradiation. As a result, a maximum sugar yield of 59.5% was obtained by microwave irradiation at 140°C for 30 min, while external heating in an autoclave gave a sugar yield of 41.8%. We also found that an ammonium ion is the key counterion accelerating the pretreatment with molybdate. These results highlight the powerful selective delignifying capability of the H(2)O(2)-activated ammonium molybdate system energized by microwave radiation.

  9. Frank-Condon factors for H2O(+) molecular bands

    Shefov, N. N.


    The Frank-Condon factors q sub (v' v'') are calculated for the spectra of the H2O(+) molecule by the method of Volkenstein et al. (1972). The results are presented in a table for values of v' from 5 to 17 and of v'' from zero to 4, indicating which bands have been observed either in the laboratory or in comets. It is shown that the photon scattering coefficient of Chamberlain (1978) can be calculated using these data for the (8,0) band; values of about 0.060 for the earth and about 0.17 for Halley's comet (at its 1986 perihelion) are determined.

  10. H2O Nucleation Around Noble Metal Cations

    Calaminici, Patrizia; Oropeza Alfaro, Pavel; Juarez Flores, Martin; Köster, Andreas; Beltran, Marcela; Ulises Reveles, J.; Khanna, Shiv N.


    First principle electronic structure calculations have been carried out to investigate the ground state geometry, electronic structure and binding energy of noble metal cations (H2O)n^+ clusters containing up to 10 H2O molecules. The calculations are performed with the density functional theory code deMon2k [1]. Due to the very flat potential energy surface of these systems special care to the numerical stability of energy and gradient calculation must be taken.Comparison of the results obtained with Cu^+, Ag^+ and Au^+ will be shown. This investigation provides insight into the structural arrangement of the water molecules around these metals and a microscopic understanding of the observed incremental binding energy in the case of the gold cation based on collision induced dissociation experiments. [1] A.M. Köster, P. Calaminici, M.E. Casida, R. Flores-Moreno, G. Geudtner, A. Goursot, T. Heine, A. Ipatov, F. Janetzko, J. Martin del Campo, S. Patchkovski, J.U. Reveles, A. Vela and D.R. Salahub, deMon2k, The deMon Developers, Cinvestav, 2006

  11. Proton ordering in tetragonal and monoclinic H2O ice

    Yen, Fei; Berlie, Adam; Liu, Xiaodi; Goncharov, Alexander F


    H2O ice remains one of the most enigmatic materials as its phase diagram reveals up to sixteen solid phases. While the crystal structure of these phases has been determined, the phase boundaries and mechanisms of formation of the proton-ordered phases remain unclear. From high precision measurements of the complex dielectric constant, we probe directly the degree of ordering of the protons in H2O tetragonal ice III and monoclinic ice V down to 80 K. A broadened first-order phase transition is found to occur near 202 K we attribute to a quenched disorder of the protons which causes a continuous disordering of the protons during cooling and metastable behavior. At 126 K the protons in ice III become fully ordered, and for the case of ice V becoming fully ordered at 113 K forming ice XIII. Two triple points are proposed to exist: one at 0.35 GPa and 126 K where ices III, IX and V coexist; and another at 0.35 GPa and 113 K where ices V, IX and XIII coexist. Our findings unravel the underlying mechanism driving th...

  12. Experimental evidence of superionic conduction in H2O ice

    Sugimura, Emiko; Komabayashi, Tetsuya; Ohta, Kenji; Hirose, Kei; Ohishi, Yasuo; Dubrovinsky, Leonid S.


    Ionic conductivity and molar volume measurements were performed on H2O ice at high pressure (P) and temperature (T) in a resistive-heated diamond anvil cell. The conductivity data obtained at P = 20-62 GPa, T = 304-930 K are well fitted with a single Arrhenius equation. Isothermal volume measurements at T = 873 K, P = 30-101 GPa indicate that H2O ice undergoes phase transitions at P = 50 GPa and 53 GPa due to hydrogen-bond symmetrization. Combining these results, we suggest that the conduction mechanism does not change with pressure-induced hydrogen-bond symmetrization. Along the Arrhenius behavior of conductivity data, the experimental evidence for superionic conduction (>10-1 S/cm) was found at T = 739 K, P = 56 GPa and T = 749 K, P = 62 GPa, which is significantly low temperature compared with earlier theoretical estimates resorted to the observation of a drastic rise of the melting curve. We infer that the sudden increase of the melting temperature is not related to the onset of superionic conduction, but is attributed to the phase change regarding to the symmetrization.

  13. The effect of H2O on ice photochemistry

    Oberg, Karin I; Linnartz, Harold; Andersson, Stefan


    UV irradiation of simple ices is proposed to efficiently produce complex organic species during star- and planet-formation. Through a series of laboratory experiments, we investigate the effects of the H2O concentration, the dominant ice constituent in space, on the photochemistry of more volatile species, especially CH4, in ice mixtures. In the experiments, thin (~40 ML) ice mixtures, kept at 20-60 K, are irradiated under ultra-high vacuum conditions with a broad-band UV hydrogen discharge lamp. Photodestruction cross sections of volatile species (CH4 and NH3) and production efficiencies of new species (C2H6, C2H4, CO, H2CO, CH3OH, CH3CHO and CH3CH2OH) in water-containing ice mixtures are determined using reflection-absorption infrared spectroscopy during irradiation and during a subsequent slow warm-up. The four major effects of increasing the H2O concentration are 1) an increase of the destruction efficiency of the volatile mixture constituent by up to an order of magnitude due to a reduction of back react...

  14. Infrared absorption of H_2_O toward massive young stars.

    van Dishoeck, E. F.; Helmich, F. P.


    We present ISO-SWS observations of absorption lines of gas-phase water within its bending vibrational mode at 6μm toward four massive young stars, which cover a range in physical parameters. Hot water with an excitation temperature >200K is detected toward GL 2136 and GL 4176, in addition to GL 2591 discussed by Helmich et al. (1996A&A...315L.173H). The abundance of water with respect to H_2_ is high in these regions, ~(2-3)x10^-5^, and comparable to the solid H_2_O abundance. In contrast, no gas-phase water absorption lines are seen toward NGC 7538 IRS9. The amount of gas-phase water is correlated with the column density of warm gas along the line of sight. Infrared observations of a larger variety of sources may provide insight into the relative importance of evaporation of grain mantles vs. high temperature gas-phase chemistry in producing the observed high abundance of H_2_O.

  15. Quantum yields for OH production from 193 and 248 nm photolysis of HNO3 and H2O2

    Schiffman, A.; Nelson, D. D., Jr.; Nesbitt, D. J.


    Flash kinetic spectroscopy in a flow tube is used to measure at room temperature the absolute yields for OH production from 193 and 248 nm photolysis of HNO3 and H2O2. The OH radicals are produced by excimer laser photolysis and probed via direct absorption of high resolution tunable IR laser light. The results indicate quantum yields for both precursors at both wavelengths which are less than the maximum possible values of 1 for H2O2. The present measurements are discussed in light of contrasting results suggested from other work.

  16. Growth and characterization of Ni(x)Zn(1-x)SO4·7H2O single crystals.

    Kavitha, J M; Mahadevan, C K


    NiSO4·7H2O (morenosite) and ZnSO4·7H2O (goslarite) are hydrogen bonded crystals having wide applications in various fields. In an attempt to understand the formation and properties of mixed crystals based on NiSO4·7H2O and ZnSO4·7H2O, we have grown by the free evaporation method at room temperature and characterized Ni(x)Zn(1-x)SO4·7H2O single crystals (with x having the values 0.0, 0.2, 0.4, 0.5, 0.6, 0.8 and 1.0). The grown crystals were characterized chemically and structurally by carrying out density, X-ray powder diffraction, and atomic absorption and Fourier transform infrared spectral measurements. The grown crystals exhibit good optical transparency in the wavelength range 210-1100 nm. The second harmonic generation measurements indicate a maximum efficiency for the mixed crystal with x = 0.5. Results of microhardness measurements follow the normal indentation size effect. Electrical (AC and DC) measurements indicate that the grown crystals exhibit a normal dielectric behavior and the electrical conduction is understood to be due to the protonic movement. The present study indicates that the mixed crystals with x = 0.2 and 0.5 are not only promising nonlinear optical materials but also useful as low dielectric constant materials.

  17. Effect of H2O2 dosing strategy on sludge pretreatment by microwave-H2O2 advanced oxidation process.

    Wang, Yawei; Wei, Yuansong; Liu, Junxin


    Considering characteristics of breaking down H(2)O(2) into water and molecular oxygen by catalase in waste activated sludge (WAS), the effect of H(2)O(2) dosing strategy on sludge pretreatment by the advanced oxidation process (AOP) of microwave-H(2)O(2) was investigated by batch experiments for optimizing H(2)O(2) dosage. Results showed that the catalase in sludge was active at the low temperature range between 15 degrees C and 45 degrees C, and gradually lost activity from 60 degrees C to 80 degrees C. Therefore, the H(2)O(2) was dosed at 80 degrees C, to which the waste activated sludge was first heated by the microwave (MW), and then the sludge dosed with H(2)O(2) was continuously heated till 100 degrees C by the microwave. Results at different H(2)O(2) dosages showed that the higher the H(2)O(2) dosing ratio was, the more the SCOD and total organic carbon (TOC) were released into the supernatant, and the optimum range of H(2)O(2)/TCOD ratio should be between 0.1 and 1.0. The percentages of consumed H(2)O(2) in the AOP of microwave and H(2)O(2) treating the WAS were 25.38%, 22.53%, 14.82%, 13.61% and 19.63% at different H(2)O(2)/TCOD dosing ratios of 0.1, 0.5, 1, 2, 4, respectively. Along with the increasing H(2)O(2)/TCOD ratio, the contents of TCOD on particles, soluble substances and mineralization increased and the TCOD distribution on solids decreased.

  18. Catalase activity is stimulated by H(2)O(2) in rich culture medium and is required for H(2)O(2) resistance and adaptation in yeast.

    Martins, Dorival; English, Ann M


    Catalases are efficient scavengers of H2O2 and protect cells against H2O2 stress. Examination of the H2O2 stimulon in Saccharomyces cerevisiae revealed that the cytosolic catalase T (Ctt1) protein level increases 15-fold on H2O2 challenge in synthetic complete media although previous work revealed that deletion of the CCT1 or CTA1 genes (encoding peroxisomal/mitochondrial catalase A) does not increase the H2O2 sensitivity of yeast challenged in phosphate buffer (pH 7.4). This we attributed to our observation that catalase activity is depressed when yeast are challenged with H2O2 in nutrient-poor media. Hence, we performed a systematic comparison of catalase activity and cell viability of wild-type yeast and of the single catalase knockouts, ctt1∆ and cta1∆, following H2O2 challenge in nutrient-rich medium (YPD) and in phosphate buffer (pH 7.4). Ctt1 but not Cta1 activity is strongly induced by H2O2 when cells are challenged in YPD but suppressed when cells are challenged in buffer. Consistent with the activity results, exponentially growing ctt1∆ cells in YPD are more sensitive to H2O2 than wild-type or cta1∆ cells, whereas in buffer all three strains exhibit comparable H2O2 hypersensitivity. Furthermore, catalase activity is increased during adaptation to sublethal H2O2 concentrations in YPD but not in buffer. We conclude that induction of cytosolic Ctt1 activity is vital in protecting yeast against exogenous H2O2 but this activity is inhibited by H2O2 when cells are challenged in nutrient-free media.

  19. Catalase activity is stimulated by H2O2 in rich culture medium and is required for H2O2 resistance and adaptation in yeast

    Dorival Martins


    Full Text Available Catalases are efficient scavengers of H2O2 and protect cells against H2O2 stress. Examination of the H2O2 stimulon in Saccharomyces cerevisiae revealed that the cytosolic catalase T (Ctt1 protein level increases 15-fold on H2O2 challenge in synthetic complete media although previous work revealed that deletion of the CCT1 or CTA1 genes (encoding peroxisomal/mitochondrial catalase A does not increase the H2O2 sensitivity of yeast challenged in phosphate buffer (pH 7.4. This we attributed to our observation that catalase activity is depressed when yeast are challenged with H2O2 in nutrient-poor media. Hence, we performed a systematic comparison of catalase activity and cell viability of wild-type yeast and of the single catalase knockouts, ctt1∆ and cta1∆, following H2O2 challenge in nutrient-rich medium (YPD and in phosphate buffer (pH 7.4. Ctt1 but not Cta1 activity is strongly induced by H2O2 when cells are challenged in YPD but suppressed when cells are challenged in buffer. Consistent with the activity results, exponentially growing ctt1∆ cells in YPD are more sensitive to H2O2 than wild-type or cta1∆ cells, whereas in buffer all three strains exhibit comparable H2O2 hypersensitivity. Furthermore, catalase activity is increased during adaptation to sublethal H2O2 concentrations in YPD but not in buffer. We conclude that induction of cytosolic Ctt1 activity is vital in protecting yeast against exogenous H2O2 but this activity is inhibited by H2O2 when cells are challenged in nutrient-free media.

  20. Crystal Structure and Interaction with DNA of [Ni(phen)(mal)(H2O)2]·3H2O

    GAO En-Jun; CHEN Mao-Sheng; YU Ying; SUN Ya-Guang


    A new complex [Ni(phen)(mal)(H2O)2]·3H2O (phen = 1,10-phenanthroline,mal2-= malonic acid) has been synthesized by the reaction of nickel nitrate,phen and malonic acid.EA,IR spectra and X-ray single-crystal diffraction were carried out to determine the composition and crystal structure of the title complex.Crystal data:monoclinic system,space group P2/c,a =8.937(3),b = 12.163(5),c = 9.725(3)(A),β = 119.36°,C15H19N2O9Ni,Mr= 430.03,Z = 2,F(000) =446,V = 921.3 (A)3,Dc = 1.550 g/cm3,μ = 1.104 mm-1,-10≤h≤ 10,-12≤k≤ 14,-11 ≤l≤7,R =0.0261 and wR = 0.0609 for 4376 (Rint = 0.0203) independent reflections and 1631 observed ones (I> 2σ(I)).Ni(Ⅱ) exhibits an octahedral coordination geometry,with hydrogen bonds and π-π interactions stabilizing the whole structure.UV spectrum of the complex interacting with protamine DNA indicates that the title compound interacts with DNA via insertion mode with bonding constant Kb of 1.11 × 104.

  1. Synthesis and Crystal Structure of a Macrocycle [Cu(dadm)(mal)(H2O)]2·2H2O

    林郑忠; 江飞龙; 陈莲; 洪茂椿


    The reaction of 4,4′-diaminodiphenylmethane (dadm), malonic acid (H2mal) and Cu(NO3)2 in aqueous solution results in a discrete binuclear Cu(II) macrocycle: [Cu(dadm)(mal)- (H2O)]2(2H2O. It crystallizes in monoclinic, space group P21/c with a = 15.231(3), b = 11.847(2), c = 9.801(2)A,Z= 106.75(3)o, V = 1693.5(6)A3, Z = 2, C32H40Cu2N4O12, Mr = 799.76, Dc = 1.568 g/cm3, λ(MoK() = 0.71073A, μ = 1.325 mm-1, F(000) = 828, the final R = 0.0531 and Wr = 0.1244 for 3421 observed reflections with I > 2σ(I). Each Cu(II) is coordinated by two oxygen atoms from a mal ligand, two nitrogen atoms from two dadm ligands and a water oxygen atom to form a triangle bipyramidal motif. The title compound possesses a distorted macrocycle enclosed by dadm with approximate dimensions of 8.3A× 5.9A.

  2. Quasiparticle Interfacial Level Alignment of Highly Hybridized Frontier Levels: H2O on TiO2(110)

    Migani, Annapaola; Mowbray, Duncan J.; Zhao, Jin; Petek, Hrvoje


    Knowledge of the frontier levels’ alignment prior to photoirradiation is necessary to achieve a complete quantitative description of H2O photocatalysis on TiO2(110). Although H2O on rutile TiO2(110) has been thoroughly studied both experimentally and theoretically, a quantitative value for the energy of the highest H2O occupied levels is still lacking. For experiment, this is due to the H2O levels being obscured by hybridization with TiO2(110) levels in the difference spectra obtained via ultraviolet photoemission spectroscopy (UPS). For theory, this is due to inherent difficulties in properly describing many-body effects at the H2O–TiO2(110) interface. Using the projected density of states (DOS) from state-of-the-art quasiparticle (QP) G0W0, we disentangle the adsorbate and surface contributions to the complex UPS spectra of H2O on TiO2(110). We perform this separation as a function of H2O coverage and dissociation on stoichiometric and reduced surfaces. Due to hybridization with the TiO2(110) surface, the H2O 3a1 and 1b1 levels are broadened into several peaks between 5 and 1 eV below the TiO2(110) valence band maximum (VBM). These peaks have both intermolecular and interfacial bonding and antibonding character. We find the highest occupied levels of H2O adsorbed intact and dissociated on stoichiometric TiO2(110) are 1.1 and 0.9 eV below the VBM. We also find a similar energy of 1.1 eV for the highest occupied levels of H2O when adsorbed dissociatively on a bridging O vacancy of the reduced surface. In both cases, these energies are significantly higher (by 0.6 to 2.6 eV) than those estimated from UPS difference spectra, which are inconclusive in this energy region. Finally, we apply self-consistent QPGW (scQPGW1) to obtain the ionization potential of the H2O–TiO2(110) interface.

  3. Responsive mechanism of a newly synthesized fluorescent probe for sensing H2O2, NO and H2O2/NO

    Zhang, Yu-Jin; Wang, Xin; Zhou, Yong; Zhao, Ke; Wang, Chuan-Kui


    Optical properties of a newly synthesized fluorescent probe for H2O2, NO and H2O2/NO are investigated by employing time-dependent density functional theory. Three different sets of fluorescence signals are obtained when the probe reacts with H2O2, NO and H2O2/NO. Analysis of molecular orbitals is presented to explore responsive mechanism of the probe for the detected objects, where the fluorescent resonance energy transfer process is for H2O2 (H2O2/NO) and the intramolecular charge transfer process is for NO. Our results provide theoretical explanation of the experimental results, and importantly, suggest possibility of the probe as a two-photon fluorescent sensor.

  4. Dynamical Behaviour of H2O in Silica Gel

    王燕; 董顺乐


    The vibrational spectra of silica gel with low concentrations of water, 3%0 and 10%, were studied by inelastic neutron scattering at 5 K. The experimental spectrum for 3% water in silica gelshows dramatic changes compared to the spectra for the other known ice phases in the energy transfer region of 2 - 140 meV. Its intermolecular librational band is shifted to lower energy by about 20meV (or by a factor of 1.43) compared to ice Ih, and shows a similar librational band with liquid at 290K. A significant excess of low-frequency vibration modes (< 7 meV)over normal ice Ih and a very wide acoustic peak (4 - 15 meV) were observed. Experimental data indicate that little H2O (3%) in silica gelexhibits a strong softening of hydrogen bonds compared to bulk normal ice and all the other known ice phases.

  5. Infrared Characters of Host Galaxies with H2O Megamaser



    Infrared characters of all the host galaxies with the H2O megamaser have been studied. The most striking featureis the anticorrelation of S(60)/S(100) versus S(12)/S(25), and S(25)/S(60) versus S(12)/S(25). The anticorrelationin the tlux density ratio can been explained by coexistence of large and very small dust particles. The latter, whichare heated by absorption of single photon, are believed to be responsible for the bulk of 12μm radiation. If thephoton energy of the host galaxy is small, this implies large S(12)/S(25) and small S(60)/S(100). However, whenphoton energy density becomes larger, the infrared spectrum will peak at wavelengths ≤ 100 μm and enhanceemission at 25 μm. As a consequence small S(12)/S(25) and large S(60)/S(100) are observed.

  6. Synthesis, Crystal Structure and Magnetic Property of Sanwich-Type Heteropolyoxometalate Na9[{Na(H2O)2}3{Cu(H2O)}3(BiW9O33)2]·42H2O

    XUE, Gang-Lin(薛岗林); WANG, Hu-Lin(王虎林); XIE, Zhi-Hai(谢志海); SHI, Qi-Zhen(史启祯); WANG, Ji-Wu(王继武); WANG, Da-Qi(王大奇)


    The heteropolytungstate Na9[{Na(H2O)2}3{Cu(H2O)}3(BiW9O33)2]·42H2O is obtained by the reaction of Na2WO4·2H2O, Bi(NO3)3·5H2O with CuCl2·2H2O at pH≈6. The structure and chemical composition are determined by X-ray diffraction analysis and elemental analysis. The crystal data and main structure refinement are: a=1.410(3) nm, b=2.338(5) nm, c=3.173(6) nm, β=98.06(4)°, V=10.354(35) nm3, monoclinic crystal system, space group: C2/c, Z=4, R1=0.0471, wR2=0.0642 [I>2σ(I)], R1=0.1371, wR2=0.0868 (all data). [{Na(H2O)2}3{Cu(H2O)}3W9O33)2]9- has D3h symmetry. IR, UV-vis spectra, TG curve and magnetic property of the complex were also discussed. The compound exhibits an antiferromagnetic coupling with J=-8.08 cm-1 and g=2.21.

  7. Synthesis of high-surface-area spinel-type MgAl$_2$O$_4$ nanoparticles by [Al(sal)$_2$(H$_2$O)$_2$]$_2$[Mg(dipic)$_2$] and [Mg(H$_2$O)$_6$][Al(ox)$_2$(H$_2$O)$_2$]$_2$·5H$_2$O: influence of inorganic precursor type


    Spinel-type MgAl$_2$O$_4$ nanoparticles with high surface area were synthesized by thermal decomposition of three different ion-pair complexes precursors, including [Mg(H$_2$O)$_6$][Al(dipic)$_2$]$_2$·6H$_2$O, [Al(sal)$_2$(H$_2$O)$_2$]$_2$[Mg(dipic)$_2$] and [Mg(H$_2$O)$_6$][Al(ox)$_2$(H$_2$O)$_2$]$_2$·5H$_2$O. Influence of the inorganic precursor was investigated on synthesis and textural properties of magnesium aluminate nanopowders. The precursors [Mg(H$_2$O)$_6$][Al(dipic)$_2$]$_2$·6H$_2$O and [Al(sal)$_2$(H$_2$O)$_2$]$_2$[Mg(dipic)$_2$] displayed pure spinel-type MgAl$_2$O$_4$, while the sample synthesized by [Mg(H$_2$O)$_6$][Al(ox)$_2$(H$_2$O)$_2$]$_2$·5H$_2$O precursor consisted of MgAl$_2$O$_4$ and MgO. The MgAl$_2$O$_4$ synthesizedvia [Al(sal)$_2$(H$_2$O)$_2$]$_2$[Mg(dipic)$_2$] precursor exhibited higher BET specific surface area (226.7 m$^2$ g$^{−1}$) and smaller particle size than those of the samples obtained from the two other precursors.

  8. Study of the transient "free" OH radical generated in H2O-H2O2 mixtures by stimulated Raman scattering

    Li, Fangfang; Ma, Zhiwei; Wang, Shenghan; Li, Tianyu; Sun, Chenglin; Li, Zhanlong; Men, Zhiwei


    Forward and backward stimulated Raman scattering (SRS) were studied in the H2O2-H2O mixtures by a strong excitation laser with 532 nm. Only the backward SRS (BSRS) of the H2O2-H2O system shows an unexpected SRS shoulder peak at around 3600 cm- 1, which is similar to the characteristic peak of "free" OH radical. The generation of the "free" OH radical is mainly attributed to the dissociation of hydrogen peroxide (HP) molecules. Simultaneously, the ionization of HP-water clusters generates a part of "free" OH radical under the Laser-induced breakdown (LIB). The interaction of water and HP is also discussed.

  9. Submillimeter H$_2$O and H$_2$O$^+$ emission in lensed ultra- and hyper-luminous infrared galaxies at z ~ 2-4

    Yang, C; Beelen, A; González-Alfonso, E; Neri, R; Gao, Y; van der Werf, P; Weiß, A; Gavazzi, R; Falstad, N; Baker, A J; Bussmann, R S; Cooray, A; Cox, P; Dannerbauer, H; Dye, S; Guélin, M; Ivison, R; Krips, M; Lehnert, M; Michałowski, M J; Riechers, D A; Spaans, M; Valiante, E


    (abridged) We report rest-frame submillimeter H2O emission line observations of 11 HyLIRGs/ULIRGs at z~2-4 selected among the brightest lensed galaxies discovered in the Herschel-ATLAS. Using the IRAM NOEMA, we have detected 14 new H2O emission lines. The apparent luminosities of the H2O emission lines are $\\mu L_{\\rm{H_2O}} \\sim 6-21 \\times 10^8 L_\\odot$, with velocity-integrated line fluxes ranging from 4-15 Jy km s$^{-1}$. We have also observed CO emission lines using EMIR on the IRAM 30m telescope in seven sources. The velocity widths for CO and H2O lines are found to be similar. With almost comparable integrated flux densities to those of the high-J CO line, H2O is found to be among the strongest molecular emitters in high-z Hy/ULIRGs. We also confirm our previously found correlation between luminosity of H2O ($L_{\\rm{H_2O}}$) and infrared ($L_{\\rm{IR}}$) that $L_{\\rm{H_2O}} \\sim L_{\\rm{IR}}^{1.1-1.2}$, with our new detections. This correlation could be explained by a dominant role of far-infrared (FIR) ...

  10. Stepwise mechanism and H2O-assisted hydrolysis in atomic layer deposition of SiO2 without a catalyst.

    Fang, Guo-Yong; Xu, Li-Na; Wang, Lai-Guo; Cao, Yan-Qiang; Wu, Di; Li, Ai-Dong


    Atomic layer deposition (ALD) is a powerful deposition technique for constructing uniform, conformal, and ultrathin films in microelectronics, photovoltaics, catalysis, energy storage, and conversion. The possible pathways for silicon dioxide (SiO2) ALD using silicon tetrachloride (SiCl4) and water (H2O) without a catalyst have been investigated by means of density functional theory calculations. The results show that the SiCl4 half-reaction is a rate-determining step of SiO2 ALD. It may proceed through a stepwise pathway, first forming a Si-O bond and then breaking Si-Cl/O-H bonds and forming a H-Cl bond. The H2O half-reaction may undergo hydrolysis and condensation processes, which are similar to conventional SiO2 chemical vapor deposition (CVD). In the H2O half-reaction, there are massive H2O molecules adsorbed on the surface, which can result in H2O-assisted hydrolysis of the Cl-terminated surface and accelerate the H2O half-reaction. These findings may be used to improve methods for the preparation of SiO2 ALD and H2O-based ALD of other oxides, such as Al2O3, TiO2, ZrO2, and HfO2.

  11. Theoretical Modeling of Water Exchange on [Pd(H(2)O)(4)](2+), [Pt(H(2)O)(4)](2+), and trans-[PtCl(2)(H(2)O)(2)].

    Deeth, Robert J.; Elding, Lars I.


    Density functional theory is applied to modeling the exchange in aqueous solution of H(2)O on [Pd(H(2)O)(4)](2+), [Pt(H(2)O)(4)](2+), and trans-[PtCl(2)(H(2)O)(2)]. Optimized structures for the starting molecules are reported together with trigonal bipyramidal (tbp) systems relevant to an associative mechanism. While a rigorous tbp geometry cannot by symmetry be the actual transition state, it appears that the energy differences between model tbp structures and the actual transition states are small. Ground state geometries calculated via the local density approximation (LDA) for [Pd(H(2)O)(4)](2+) and relativistically corrected LDA for the Pt complexes are in good agreement with available experimental data. Nonlocal gradient corrections to the LDA lead to relatively inferior structures. The computed structures for analogous Pd and Pt species are very similar. The equatorial M-OH(2) bonds of all the LDA-optimized tbp structures are predicted to expand by 0.25-0.30 Å, while the axial bonds change little relative to the planar precursors. This bond stretching in the transition state counteracts the decrease in partial molar volume caused by coordination of the entering water molecule and can explain qualitatively the small and closely similar volumes of activation observed. The relatively higher activation enthalpies of the Pt species can be traced to the relativistic correction of the total energies while the absolute DeltaH() values for exchange on [Pd(H(2)O)(4)](2+) and [Pt(H(2)O)(4)](2+) are reproduced using relativistically corrected LDA energies and a simple Born model for hydration. The validity of the latter is confirmed via some simple atomistic molecular mechanics estimates of the relative hydration enthalpies of [Pd(H(2)O)(4)](2+) and [Pd(H(2)O)(5)](2+). The computed DeltaH() values are 57, 92, and 103 kJ/mol compared to experimental values of 50(2), 90(2), and 100(2) kJ/mol for [Pd(H(2)O)(4)](2+), [Pt(H(2)O)(4)](2+), and trans-[PtCl(2)(H(2)O)(2

  12. I + (H2O)2 → HI + (H2O)OH Forward and Reverse Reactions. CCSD(T) Studies Including Spin-Orbit Coupling.

    Wang, Hui; Li, Guoliang; Li, Qian-Shu; Xie, Yaoming; Schaefer, Henry F


    The potential energy profile for the atomic iodine plus water dimer reaction I + (H2O)2 → HI + (H2O)OH has been explored using the "Gold Standard" CCSD(T) method with quadruple-ζ correlation-consistent basis sets. The corresponding information for the reverse reaction HI + (H2O)OH → I + (H2O)2 is also derived. Both zero-point vibrational energies (ZPVEs) and spin-orbit (SO) coupling are considered, and these notably alter the classical energetics. On the basis of the CCSD(T)/cc-pVQZ-PP results, including ZPVE and SO coupling, the forward reaction is found to be endothermic by 47.4 kcal/mol, implying a significant exothermicity for the reverse reaction. The entrance complex I···(H2O)2 is bound by 1.8 kcal/mol, and this dissociation energy is significantly affected by SO coupling. The reaction barrier lies 45.1 kcal/mol higher than the reactants. The exit complex HI···(H2O)OH is bound by 3.0 kcal/mol relative to the asymptotic limit. At every level of theory, the reverse reaction HI + (H2O)OH → I + (H2O)2 proceeds without a barrier. Compared with the analogous water monomer reaction I + H2O → HI + OH, the additional water molecule reduces the relative energies of the entrance stationary point, transition state, and exit complex by 3-5 kcal/mol. The I + (H2O)2 reaction is related to the valence isoelectronic bromine and chlorine reactions but is distinctly different from the F + (H2O)2 system.

  13. Vesiculation in rhyolite at low H2O contents: A thermodynamic model

    Ryan, Amy G.; Russell, James K.; Hess, Kai-Uwe; Phillion, Andre B.; Dingwell, Donald B.


    We present experimental data on the thermodynamics and kinetics of bubble nucleation and growth in weakly H2O-oversaturated rhyolitic melts. The high-temperature (900-1100°C) experiments involve heating of rhyolitic obsidian from Hrafntinnuhryggur, Krafla, Iceland to above their glass transition temperature (Tg ˜ 690°C) at 0.1 MPa for times of 0.25-24 h. During experiments, the rhyolite cores increase in volume as H2O vapor-filled bubbles nucleate and expand. The extent of vesiculation, as tracked by porosity, is mapped in temperature-time (T-t) space. At constant temperature and for a characteristic dwell time, the rhyolite cores achieve a maximum volume where the T-t conditions reach thermochemical equilibrium. For each T-t snapshot of vesiculation, we use 3-D analysis of X-ray computed tomographic (XCT) images of the quenched cores to obtain the bubble number density (BND) and bubble-size distribution (BSD). BNDs for the experimental cores are insensitive to T and t, indicating a single nucleation event. All BSDs converge to a common distribution, independent of T, melt viscosity (η), or initial degree of saturation, suggesting a common growth process. We use these data to calibrate an empirical model for predicting the rates and amounts of vesiculation in rhyolitic melts as a function of η and thermochemical affinity (A): two computable parameters that are dependent on T, pressure and H2O content. The model reproduces the experimental data set and data from the literature to within experimental error, and has application to natural volcanic systems where bubble formation and growth are not diffusion limited (e.g., lavas, domes, ignimbrites, conduit infill).

  14. Oxidative dissolution of actinide oxides in H 2O 2 containing aqueous solution - A preliminary study

    Pehrman, Reijo; Amme, Marcus; Roth, Olivia; Ekeroth, Ella; Jonsson, Mats


    Oxidative dissolution of spent nuclear fuel is an important issue in the safety assessment of a future geological repository for spent nuclear fuel. Although UO 2 constitutes, in terms of mass, the majority of the spent fuel material, its main radiotoxicity is (after extended storage times) contained in actinides with half lives shorter than that of 238-uranium, such as isotopes of Np and Pu. Relatively little information is available on the dissolution behavior of Np and Pu in comparable environments. This work investigates the oxidative dissolution of NpO 2 and PuO 2 in non-complexing aqueous solutions containing H 2O 2 and compares their behavior with that of UO 2. We have found that oxidative dissolution takes place for all three actinides in the presence of H 2O 2. Based on the obtained dissolution rates, we would not expect the dissolution of the actinides to be congruent. Instead, in a system without complexing agent, the release rates of Np and Pu are expected to be lower than the U release rate.

  15. The new triazine-based porous copper phosphonate [Cu3(PPT)(H2O)3]·10H2O.

    Hermer, N; Stock, N


    High throughput methods were employed in the discovery of [Cu3(PPT)(H2O)3]·10H2O (denoted CAU-14). The structure contains one-dimensional channels with a diameter of 9.4 Å. Thermal activation leads to the formation of uncoordinated metal sites and a high water uptake of 39.1 wt% was found.

  16. Traces of H2O in Ultrahigh-Pressure Metamorphic Rocks

    Dobrzhinetskaya, L. F.


    Ultrahigh-pressure (UHP) metamorphic rocks accommodate a significant amount of H2O at high pressures and temperatures during their deep subduction. Fluid-driven processes are responsible for mineral reactions; they may trigger phase transformations and provide a decisive weakening effect on the rheological behavior of the rocks during deep subduction, or they may lead to brittle failure and earthquakes. Dehydration reactions, producing fluid (i.e., H2O, CO2) during regional metamorphism at low-to-mid crustal levels (P ~ 0.1 - 1 GPa), are reasonably pressure insensitive. At these levels, the maximum dehydration occurs at the greatest temperatures experienced by buried rocks. In the deep subduction zone (> 120 - 150 km), where both high pressures and temperatures operate, the situation is different. There, on the one hand, the water becomes chemically bonded and incorporated into the structure of both nominally hydrous and anhydrous minerals. On the other hand, the aqueous fluid (a supercritical fluid) dissolves a considerable amount of mineral components at high pressures and temperatures, and a solute concentration increases as pressure is increased. Microstructural observations on ultrahigh-pressure minerals from eclogites and metasediments provide convincing evidence of fluid involvement as deep as the upper mantle and possibly, the mantle transition zone. Diamond is one of the minerals of great importance because it unambiguously records the high pressure (minimum 4 GPa and possibly > 4GPa) at which the host rocks were recrystallized. We present here the results of studies of nano-inclusions associated with dislocations of growth and/or with interstitial defects of carbon in diamond structure obtained with transmission electron microscopy, microRaman, and microInfrared synchrotron assisted spectroscopy. A diverse composition of multicomponent fluid and crystalline inclusions and characteristic of nitrogen aggregations, provide evidence that the diamonds were

  17. Photoelectron spectroscopic study of the hydrated nucleoside anions: Uridine(-)(H(2)O)(n=0-2), cytidine(-)(H(2)O)(n=0-2), and thymidine(-)(H(2)O)(n=0,1).

    Li, Xiang; Wang, Haopeng; Bowen, Kit H


    The hydrated nucleoside anions, uridine(-)(H(2)O)(n=0-2), cytidine(-)(H(2)O)(n=0-2), and thymidine(-)(H(2)O)(n=0,1), have been prepared in beams and studied by anion photoelectron spectroscopy in order to investigate the effects of a microhydrated environment on parent nucleoside anions. Vertical detachment energies (VDEs) were measured for all eight anions, and from these, estimates were made for five sequential anion hydration energies. Excellent agreement was found between our measured VDE value for thymidine(-)(H(2)O)(1) and its calculated value in the companion article by S. Kim and H. F. Schaefer III.

  18. Photoelectron spectroscopic study of the hydrated nucleoside anions: Uridine-(H2O)n=0-2, cytidine-(H2O)n=0-2, and thymidine-(H2O)n=0,1

    Li, Xiang; Wang, Haopeng; Bowen, Kit H.


    The hydrated nucleoside anions, uridine-(H2O)n=0-2, cytidine-(H2O)n=0-2, and thymidine-(H2O)n=0,1, have been prepared in beams and studied by anion photoelectron spectroscopy in order to investigate the effects of a microhydrated environment on parent nucleoside anions. Vertical detachment energies (VDEs) were measured for all eight anions, and from these, estimates were made for five sequential anion hydration energies. Excellent agreement was found between our measured VDE value for thymidine-(H2O)1 and its calculated value in the companion article by S. Kim and H. F. Schaefer III.

  19. H2O2 in time marine troposphere and seawater of the Atlantic Ocean (48 deg N - 63 deg S)

    Weller, Rolf; Schrems, Otto


    Concentrations of H2O2 in gas phase and seawater have been measured in pristine regions of the Atlantic Ocean during the RV Polarstern expedition ANT X-1 from 11/15/91 to 01/02/02. A broad maximum of gaseous H2O2 mixing ratio in the troposphere was found between the tropic of cancer and the tropic of capricornus with peak values around 1.8 ppbv. The observed ratio of organic peroxides/total amount of peroxides was 0.2-0.35, in contrast to the remarkably lower ratio of 0.05-0.10 measured in the continental troposphere by other groups. In the Atlantic surface seawater the H2O2 concentrations were determined to be around 0.1 micromol/L, decreasing with increasing water depth to a value below the detection limit at approximately 100 m. We observed low H2O2 concentrations (about 0.03 micromol/L) in surface water in coastal shelf regions and in the partly ice covered Weddell Sea.

  20. H2O SOS: It Begins With You

    Ingalls, G.; Weiss, I.


    ExplorOcean H2O SOS: Help Heal the Ocean—Student Operated Solutions: Operation Climate Change teaches middle and high school students about ocean threats related to climate change through hands-on activities and learning experiences in the field. In this research we study five areas of focus. Marine Debris: The Ocean is one large system with a general circulation pattern and debris will be transported around the globe. Ocean Acidification: CO2 is the shortened term for Carbon Dioxide and it is a colorless and odorless gas vital to life on earth. This naturally occurring chemical compound is composed of a carbon atom covalently double bonded to two oxygen atoms. To much CO2 in the atmosphere can become an issue for our plants due to the chemicals strong greenhouse gas effects. Sustainable Fishing: Investigate and understand the impact fishing has on the habitats and the disruption of our ecosystem. Invasive Species: Species have been moved, intentionally or unintentionally as a result of human activity, into areas where they do not occur naturally are called "introduced" or "alien species". Watersheds and storm water: Water quality is not just a coastal issue. It starts in all regions and affects water quality from the mountains to the ocean. We get much of our water here in Southern California from the Colorado River. Imagine if the citizens of Colorado polluted all their water resources. We would not be able to continue using the Colorado River for fresh water. This issue affects everyone, and all people must help try to keep our fresh water resources clean.

  1. Cutin monomers and surface wax constituents elicit H2O2 in conditioned cucumber hypocotyl segments and enhance the activity of other H2O2 elicitors

    Fauth; Schweizer; Buchala; Markstadter; Riederer; Kato; Kauss


    Hypocotyls from etiolated cucumber (Cucumis sativus L.) seedlings were gently abraded at their epidermal surface and cut segments were conditioned to develop competence for H2O2 elicitation. Alkaline hydrolysates of cutin from cucumber, tomato, and apple elicited H2O2 in such conditioned segments. The most active constituent of cucumber cutin was identified as dodecan-1-ol, a novel cutin monomer capable of forming hydrophobic terminal chains. Additionally, the cutin hydrolysates enhanced the activity of a fungal H2O2 elicitor, similar to cucumber surface wax, which contained newly identified alkan-1,3-diols. The specificity of elicitor and enhancement activity was further elaborated using some pure model compounds. Certain saturated hydroxy fatty acids were potent H2O2 elicitors as well as enhancers. Some unsaturated epoxy and hydroxy fatty acids were also excellent H2O2 elicitors but inhibited the fungal elicitor activity. Short-chain alkanols exhibited good elicitor and enhancer activity, whereas longer-chain alkan-1-ols were barely active. The enhancement effect was also observed for H2O2 elicitation by ergosterol and chitosan. The physiological significance of these observations might be that once the cuticle is degraded by fungal cutinase, the cutin monomers may act as H2O2 elicitors. Corrosion of cutin may also bring surface wax constituents in contact with protoplasts and enhance elicitation.

  2. Application of H2O2 and H2O2/Fe0 in removal of Acid Red 18 dye from aqueous solutions

    Nazari Shahram


    Full Text Available Background & Aims of the Study: Organic dyes with a complex structure are often toxic, carcinogenic, mutagenic, non-biodegradation and stable in the environment and if released to the environment without treatment can endanger the environment and human health. The aim of this study was to evaluate the performance of H2O2 and H2O2/Fe0 Iron in removal of dye Acid Red 18 from aqueous solutions. Materials & Methods: This study was conducted at the laboratory scale. In this study, the removal efficiency of Acid Red 18 from a synthetic solution by H2O2 and H2O2/Fe0 was investigated. As well as Effect of solution pH, dye concentration, Concentration of Nanoscale Zero-Valent Iron, H2O2 and contact time in decolorization efficiency was investigated. Results: Results show that in pH=3, Contact time of 80 minutes, dye concentration of 50 mg/l and Concentration of Nanoscale Zero-Valent Iron of 2 g/l and H2O2 concentration equal to 200 mmol/l, the removal efficiency was about 98%. Conclusions: According to the results of experiments, H2O2/Fe0 has high efficiency in removal of Acid Red 18 from aqueous solution.

  3. H 2O in basalt and basaltic andesite glass inclusions from four subduction-related volcanoes

    Sisson, T. W.; Layne, G. D.


    Total dissolved H 2O and major element abundances were measured in basalt and basaltic andesite glass inclusions in olivine phenocrysts from Quaternary eruptions of four subduction-related volcanoes to test the hypothesis that low-MgO high-alumina basalts contain high H 2O at depth [1] and to reveal any petrogenetically significant correlations between arc basalt compositions and H 2O contents. Total dissolved H 2O (combined molecular H 2O and OH groups) measured by ion microprobe in mafic glass inclusions from the 1974 eruption of Fuego, Guatemala, reaches 6.2 wt.%. Dissolved H 2O contents decrease in more evolved Fuego glasses. Correlations of H 2O with MgO, Na 2O, K 2O, S and Cl indicate that aqueous fluid exsolution during magma ascent forced crystallization and differentiation of residual liquids. Low-K 2O magnesian high-alumina basalt glass inclusions from the 3 ka eruption of Black Crater (Medicine Lake volcano, California) have low H 2O contents, near 0.2 wt.%, which are consistent with the MORB-like character of these and other primitive lavas of the Medicine Lake region. Basalt and basaltic andesite glass inclusions from Copco Cone and Goosenest volcano on the Cascade volcanic front north of Mt. Shasta have H 2O contents of up to 3.3 wt.%. The range of H 2O contents in Cascade mafic magmas is too large to have resulted solely from enrichment by crystallization and indicates the participation of an H 2O-rich component in magma generation or crustal-level modification. Whereas fluid-absent melting of amphibole-bearing peridotite can account for the H 2O in most mafic arc liquids, the very high H 2O/alkali ratios of the 1974 Fuego eruptives suggest that an aqueous fluid was involved in the generation of Fuego basalts.

  4. Magnetic Properties of a Three-dimensional Supramolecular Complex[Co(hmt)2(SCN)2(H2O)2][Co(SCN)2(H2O)4](H2O)2%三维超分子配合物[Co(hmt)2(SCN)2(H2O)2][Co(SCN)2(H2O)4](H2O)2的磁性质(英文)

    李纲; 李金鹏; 王翠红; 李林科; 侯红卫


    Supramolecular complex [Co(hmt)2(SCN)2(H2O)2][Co(SCN)2(H2O)4](H2O)2 (hmt =hexamethylenetetramine) is prepared according to previous literature. The determination of variable-temperature magnetic susceptibilities (5~300 K) shows that the magnetic behavior obeys the Curie-Weiss law over the whole temperature range. In this compound weak antiferromagnetic coupling can be observed.%参照文献制备了三维超分子配合物[Co(hmt)2(SCN)2(H2O)2][Co(SCN)2(H2O)4](H2O)2, 测试了该化合物在5~300 K范围内的变温磁化率.结果表明,其磁行为在测定的温度范围内遵守Curie-Weiss定律, 金属离子之间存在弱的反铁磁偶合.

  5. Green hydrophilic modification of PE hollow fiber membranes in a module scale via long-distance and dynamic low-temperature H2O plasma flow

    Li, Mei-Sheng; Zhao, Zhi-Ping; Wang, Ming-Xing


    A green chemistry process, long-distance and dynamic low-temperature (LDDLT) H2O plasma, was developed to modify PE hollow fiber membranes in a module scale using our modified LDDLT plasma setup. The modification degree of LDDLT-H2O plasma was 2 times greater than that of Ar plasma, but the effective treatment distance achieved by LDDLT-Ar plasma was about two times of that obtained by LDDLT-H2O plasma (22 cm). Under the suitable conditions, the effective treatment distance can reach over 54 cm after LDDLT-H2O plasma treatment from the double inlets, closed to some industrial module sizes. The improvement in surface hydrophilicity was because of the introduction of numerous oxygen-containing groups. High concentrations of OH radicals in H2O plasma played a major role in the membrane surface hydroxylation. This directly resulted in a great enhancement in the pure water flux. It increased from about 6 L m-2 h-1 to 45 L m-2 h-1 after treatment. Also, the H2O plasma-treated membrane module exhibited good hydrophilic stability during 285 days storage.

  6. Submillimeter H2O and H2O+emission in lensed ultra- and hyper-luminous infrared galaxies at z 2-4

    Yang, C.; Omont, A.; Beelen, A.; González-Alfonso, E.; Neri, R.; Gao, Y.; van der Werf, P.; Weiß, A.; Gavazzi, R.; Falstad, N.; Baker, A. J.; Bussmann, R. S.; Cooray, A.; Cox, P.; Dannerbauer, H.; Dye, S.; Guélin, M.; Ivison, R.; Krips, M.; Lehnert, M.; Michałowski, M. J.; Riechers, D. A.; Spaans, M.; Valiante, E.


    We report rest-frame submillimeter H2O emission line observations of 11 ultra- or hyper-luminous infrared galaxies (ULIRGs or HyLIRGs) at z 2-4 selected among the brightest lensed galaxies discovered in the Herschel-Astrophysical Terahertz Large Area Survey (H-ATLAS). Using the IRAM NOrthern Extended Millimeter Array (NOEMA), we have detected 14 new H2O emission lines. These include five 321-312ortho-H2O lines (Eup/k = 305 K) and nine J = 2 para-H2O lines, either 202-111(Eup/k = 101 K) or 211-202(Eup/k = 137 K). The apparent luminosities of the H2O emission lines are μLH2O 6-21 × 108 L⊙ (3 integrated line fluxes ranging from 4-15 Jy km s-1. We have also observed CO emission lines using EMIR on the IRAM 30 m telescope in seven sources (most of those have not yet had their CO emission lines observed). The velocity widths for CO and H2O lines are found to be similar, generally within 1σ errors in the same source. With almost comparable integrated flux densities to those of the high-J CO line (ratios range from 0.4 to 1.1), H2O is found to be among the strongest molecular emitters in high-redshift Hy/ULIRGs. We also confirm our previously found correlation between luminosity of H2O (LH2O) and infrared (LIR) that LH2O LIR1.1-1.2, with ournew detections. This correlation could be explained by a dominant role of far-infrared pumping in the H2O excitation. Modelling reveals that the far-infrared radiation fields have warm dust temperature Twarm 45-75 K, H2O column density per unit velocity interval NH2O /ΔV ≳ 0.3 × 1015 cm-2 km-1 s and 100 μm continuum opacity τ100> 1 (optically thick), indicating that H2O is likely to trace highly obscured warm dense gas. However, further observations of J ≥ 4 H2O lines are needed to better constrain the continuum optical depth and other physical conditions of the molecular gas and dust. We have also detected H2O+ emission in three sources. A tight correlation between LH2O and LH2O+ has been found in galaxies from low to high

  7. Preparation, Characterization and Properties of Ag(Ⅰ) Coordination Polymer [Ag2(bpp) 2(H2O)]·pydc·7H2O

    GUO, Chunyan; WEN, Guilin; WANG, Yaoyu; FU, Aiyun; LERMONTOVA, ElmiraKh; SHI, Qizhen


    A new coordination polymer, [Ag2(bpp)2(H2O)]·pydc·7H2O (1), derived from the ligand pyridine-3,5- dicarboxylic acid (H2pydc), has been obtained through a hydrothermal technique [bpp=1,3-bis(4-pyridyl)propane]. Its single crystal structure has been determined by X-ray crystallography. A 2D sheet containing (H2O)12 water units was formed. Interestingly, each pydc dianion bridged two (H2O)12 units and two free water molecules in the con- struction of 2D hydrogen-bonding sheets. Additionally, fluorescent properties, TG analysis, and PXRD for complex 1 were also measured and discussed.

  8. Ro-vibrational spectrum of H2O-Ne in the ν2 H2O bending region: A combined ab initio and experimental investigation

    Liu, Xunchen; Hou, Dan; Thomas, Javix; Li, Hui; Xu, Yunjie


    High resolution ro-vibrational transitions of the H2O-Ne complex in the ν2 bending region of H2O at 6 μm have been measured using a rapid scan infrared spectrometer based on an external cavity quantum cascade laser and an astigmatic multipass optical cell. To aid the spectral assignment, a four-dimension potential energy surface of H2O-Ne which depends on the intramolecular bending coordinate of the H2O monomer and the three intermolecular vibrational coordinates has been constructed and the rovibrational transitions have been calculated. Three ortho and two para H2O-20Ne bands have been identified from the experimental spectra. Some weaker transitions belonging to H2O-22Ne have also been identified experimentally. Spectroscopic fits have been performed for both the experimental and theoretical transition frequencies using a simple pseudo-diatomic Hamiltonian including both Coriolis coupling and Fermi resonance terms. The experimental and theoretical spectroscopic constants thus obtained have been compared. Further improvements needed in the potential energy surface and the related spectral simulation have been discussed.


    Yi-hong Lu; Gen-shuan Wei; Jing Peng


    In order to obtain the chitosan oligomers, chitosan was irradiated in the solid state with and without H2O2 as a radiation degradation sensitizer, respectively. At room temperature, the viscosity average-molecular weight (Mη) of chitosan was decreased from 1.6 × 106 to 2.2 × 105 at an absorbed dose of 72 kGy without H2O2, and decreased to 2.7 × 104 at 2 kGy in the presence of an appropriate H2O2 content. In addition, the radiation degradation rate of chitosan containing 38.2wt%H2O2 is 59 times higher than that in the solid state without H2O2. FT-IR analysis suggests that there is no obvious change in the chemical structure of irradiated chitosan with and without H2O2 at a dose below 20 kGy, compared with unirradiated chitosan. On the other hand, the degree of deacetylation (DD) of irradiated chitosan in the studied dose range changed slightly, while DD of irradiated chitosan with H2O2 increased significantly. The XRD pattern indicates that the irradiated chitosan with H2O2 has more perfect crystalline structure than unirradiated chitosan. Therefore, it could be expected that irradiation of chitosan using H2O2 as a sensitizer would be a very effective method to prepare low molecular weight chitosan,because of its feasibility and benignancy to environment.

  10. A dual electrolyte H2/O2 planar membraneless microchannel fuel cell system with open circuit potentials in excess of 1.4 V.

    Cohen, Jamie L; Volpe, David J; Westly, Daron A; Pechenik, Alexander; Abruña, Héctor D


    A dual electrolyte H2/O2 fuel cell system employing a planar microfluidic membraneless fuel cell has been investigated and compared to single electrolyte H2/O2 systems under analogous conditions. The fuel is H2 dissolved in 0.1 M KOH (pH 13), and the oxidant is O2 dissolved in 0.1 M H2SO4 (pH 0.9), comprising a system with a calculated thermodynamic potential of 1.943 V (when 1 M H2 and O2 concentrations are assumed). This value is well above the calculated thermodynamic maximum of 1.229 V for an acid, or alkaline, single electrolyte H2/O2 fuel cell. Experimentally, open-circuit potentials in excess of 1.4 V have been achieved with the dual electrolyte system. This is a 500 mV increase in the open circuit potentials observed for single electrolyte H2/O2 systems also studied. The dual electrolyte fuel cell system shows power generation of 0.6 mW/cm2 from a single device, which is nearly 0.25 mW/cm2)greater than the values obtained for single electrolyte H2/O2 fuel cell systems studied. Microchannels of varying dimensions have been employed to study both the single and dual electrolyte H2/O2 systems. Channel thickness variation and the flow rate dependences of power generation are also addressed.

  11. Transcriptome analysis of H2O2-treated wheat seedlings reveals a H2O2-responsive fatty acid desaturase gene participating in powdery mildew resistance.

    Aili Li

    Full Text Available Hydrogen peroxide (H(2O(2 plays important roles in plant biotic and abiotic stress responses. However, the effect of H(2O(2 stress on the bread wheat transcriptome is still lacking. To investigate the cellular and metabolic responses triggered by H(2O(2, we performed an mRNA tag analysis of wheat seedlings under 10 mM H(2O(2 treatment for 6 hour in one powdery mildew (PM resistant (PmA and two susceptible (Cha and Han lines. In total, 6,156, 6,875 and 3,276 transcripts were found to be differentially expressed in PmA, Han and Cha respectively. Among them, 260 genes exhibited consistent expression patterns in all three wheat lines and may represent a subset of basal H(2O(2 responsive genes that were associated with cell defense, signal transduction, photosynthesis, carbohydrate metabolism, lipid metabolism, redox homeostasis, and transport. Among genes specific to PmA, 'transport' activity was significantly enriched in Gene Ontology analysis. MapMan classification showed that, while both up- and down- regulations were observed for auxin, abscisic acid, and brassinolides signaling genes, the jasmonic acid and ethylene signaling pathway genes were all up-regulated, suggesting H(2O(2-enhanced JA/Et functions in PmA. To further study whether any of these genes were involved in wheat PM response, 19 H(2O(2-responsive putative defense related genes were assayed in wheat seedlings infected with Blumeria graminis f. sp. tritici (Bgt. Eight of these genes were found to be co-regulated by H(2O(2 and Bgt, among which a fatty acid desaturase gene TaFAD was then confirmed by virus induced gene silencing (VIGS to be required for the PM resistance. Together, our data presents the first global picture of the wheat transcriptome under H(2O(2 stress and uncovers potential links between H(2O(2 and Bgt responses, hence providing important candidate genes for the PM resistance in wheat.

  12. Nuclear Magnetic Resonance as a Probe of Meso-timescale Dynamics: Ion and H2O Behavior at Mineral-H2O Interfaces

    Bowers, G. M.; Kirkpatrick, R. J.; Singer, J. W.


    One of the important meso-scales in geochemistry is the meso-timescale that is characteristic of processes too slow to probe with light spectroscopy but too fast to probe macroscopically. Nuclear magnetic resonance (NMR) spectroscopy is one of the only analytical methods with dynamic sensitivity to motions with correlation times on the 10-9 to 1 s timescales and is thus a uniquely powerful probe of meso-timescale dynamic behavior. Here, we describe the results of several studies exploring the meso-timescale motion of ions and H2O at the mineral-H2O interface of hectorite, a smectite clay mineral.1-3 2H, 23Na, 39K and 43Ca NMR results show that H2O molecules associated with the interface undergo anisotropic reorientation due to proximity to the surface and surface-associated cations. This motion can be described by rotational diffusion of the H2O molecule about its C2 symmetry axis at GHz frequencies combined with hopping of the H2O molecule about the normal to the smectite surface at ~>200 kHz. This model describes well the observed 2H NMR spectra of Na+, K+, and Ca2+ hectorites over a range temperatures between -80°C and 50°C, with the specific range dependent only on the total system H2O content. At temperatures above -20°C, systems with excess H2O with respect to a two-layer hydrate (low-H2O pastes through dilute aqueous suspensions) experience additional dynamic averaging due to H2O exchange between cation hydration shells, surface-sorbed species, and bulk inter-particle water. The extent of 2H averaging due to this exchange mechanism is strongly affected by the total H2O content in the system, the identity of the charge balancing cation, and the temperature. The dynamic averaging mechanisms affecting the cationic NMR resonances in these systems become dominated by diffusional processes at progressively lower temperatures as the hydration energy of the cation increases. These interfacial cation dynamics and binding sites are strongly affected by surface

  13. Seasonal cycles and variability of O3 and H2O in the UT/LMS during SPURT

    M. Krebsbach


    Full Text Available Airborne high resolution in situ measurements of a large set of trace gases including ozone (O3 and total water (H2O in the upper troposphere and the lowermost stratosphere (UT/LMS have been performed above Europe within the SPURT project. SPURT provides an extensive data coverage of the UT/LMS in each season within the time period between November 2001 and July 2003. In the LMS a distinct spring maximum and autumn minimum is observed in O3, whereas its annual cycle in the UT is shifted by 2–3 months later towards the end of the year. The more variable H2O measurements reveal a maximum during summer and a minimum during autumn/winter with no phase shift between the two atmospheric compartments. For a comprehensive insight into trace gas composition and variability in the UT/LMS several statistical methods are applied using chemical, thermal and dynamical vertical coordinates. In particular, 2-dimensional probability distribution functions serve as a tool to transform localised aircraft data to a more comprehensive view of the probed atmospheric region. It appears that both trace gases, O3 and H2O, reveal the most compact arrangement and are best correlated in the view of potential vorticity (PV and distance to the local tropopause, indicating an advanced mixing state on these surfaces. Thus, strong gradients of PV seem to act as a transport barrier both in the vertical and the horizontal direction. The alignment of trace gas isopleths reflects the existence of a year-round extra-tropical tropopause transition layer. The SPURT measurements reveal that this layer is mainly affected by stratospheric air during winter/spring and by tropospheric air during autumn/summer. Normalised mixing entropy values for O3 and H2O in the LMS appear to be maximal during spring and summer, respectively, indicating highest variability of these trace gases during the respective seasons.

  14. A Search for Submillimeter H2O Masers in Active Galaxies: The Detection of 321 GHZ H2O Maser Emission in NGC 4945

    Hagiwara, Yoshiaki; Horiuchi, Shinji; Doi, Akihiro; Miyoshi, Makoto; Edwards, Philip G.


    We present further results of a search for extragalactic submillimeter H2O masers using the Atacama Large Millimeter/submillimeter Array (ALMA). The detection of a 321 GHz H2O maser in the nearby type 2 Seyfert galaxy, the Circinus galaxy, has previously been reported, and here the spectral analysis of four other galaxies is described. We have discovered H2O maser emission at 321 GHz toward the center of NGC 4945, a nearby type 2 Seyfert. The maser emission shows Doppler-shifted velocity features with velocity ranges similar to those of the previously reported 22 GHz H2O masers however, the non-contemporaneous observations also show differences in velocity offsets. The subparsec-scale distribution of the 22 GHz H2O masers revealed by earlier very long baseline interferometry observations suggests that the submillimeter masers could arise in an edge-on rotating disk. The maser features remain unresolved by the synthesized beam of ˜0.″54 (˜30 pc) and are located toward the 321 GHz continuum peak within errors. A marginally detected (3σ) high-velocity feature is redshifted by 579 km {{{s}}}-1 with respect to the systemic velocity of the galaxy. Assuming that this feature is real and arises from a Keplerian rotating disk in this galaxy, it is located at a radius of ˜0.020 pc (˜1.5 × 105 Schwarzschild radii), which would enable molecular material closer to the central engine to be probed than the 22 GHz H2O masers. This detection confirms that submillimeter H2O masers are a potential tracer of the circumnuclear regions of active galaxies, which will benefit from higher angular resolution studies with ALMA.

  15. Crystal structures of hydrates of simple inorganic salts. III. Water-rich aluminium halide hydrates: AlCl3 · 15H2O, AlBr3 · 15H2O, AlI3 · 15H2O, AlI3 · 17H2O and AlBr3 · 9H2O.

    Schmidt, Horst; Hennings, Erik; Voigt, Wolfgang


    Water-rich aluminium halide hydrate structures are not known in the literature. The highest known water content per Al atom is nine for the perchlorate and fluoride. The nonahydrate of aluminium bromide, stable pentadecahydrates of aluminium chloride, bromide and iodide, and a metastable heptadecahydrate of the iodide have now been crystallized from low-temperature solutions. The structures of these hydrates were determined and are discussed in terms of the development of cation hydration spheres. The pentadecahydrate of the chloride and bromide are isostructural. In AlI(3) · 15H2O, half of the Al(3+) cations are surrounded by two complete hydration spheres, with six H2O in the primary and 12 in the secondary. For the heptadecahydrate of aluminium iodide, this hydration was found for every Al(3+).

  16. Rheological properties of sewage sludge during enhanced anaerobic digestion with microwave-H2O2 pretreatment.

    Liu, Jibao; Yu, Dawei; Zhang, Jian; Yang, Min; Wang, Yawei; Wei, Yuansong; Tong, Juan


    The rheological behavior of sludge is of serious concern in anaerobic digestion. This study investigated the rheological properties of sewage sludge during enhanced anaerobic digestion with microwave-H2O2 pretreatment (MW-H2O2). The results showed that MW-H2O2 pretreatment resulted in the improvement of sludge flowability and weakening of its viscoelastic properties. Further positive effects on the rheological properties of digested sludge during anaerobic digestion were observed. The flowability was improved with a low level of apparent viscosity. The decrease of the consistency index and increase of the flow behavior index indicated that the strength of the inner structures and non-Newtonian flow characteristics of digested sludge weakened. Both the storage modulus (G') and loss modulus (G″) decreased, indicating that the viscoelastic behavior became weak. These effects were possibly attributed to the changes of the digested sludge micro-structures, such as extracellular polymeric substances (EPS). This study concluded that anaerobic digestion for treating sewage sludge combined with pretreatment is a more favorable option than single anaerobic digestion from the perspective of rheology.

  17. Nanoporous Carbon Nanofibers Decorated with Platinum Nanoparticles for Non-Enzymatic Electrochemical Sensing of H2O2

    Yang Li


    Full Text Available We describe the preparation of nanoporous carbon nanofibers (CNFs decorated with platinum nanoparticles (PtNPs in this work by electrospining polyacrylonitrile (PAN nanofibers and subsequent carbonization and binding of PtNPs. The fabricated nanoporous CNF-PtNP hybrids were further utilized to modify glass carbon electrodes and used for the non-enzymatic amperometric biosensor for the highly sensitive detection of hydrogen peroxide (H2O2. The morphologies of the fabricated nanoporous CNF-PtNP hybrids were observed by scanning electron microscopy, transmission electron microscopy, and their structure was further investigated with Brunauer–Emmett–Teller (BET surface area analysis, X-ray photoelectron spectroscopy, X-ray diffraction, and Raman spectrum. The cyclic voltammetry experiments indicate that CNF-PtNP modified electrodes have high electrocatalytic activity toward H2O2 and the chronoamperometry measurements illustrate that the fabricated biosensor has a high sensitivity for detecting H2O2. We anticipate that the strategies utilized in this work will not only guide the further design and fabrication of functional nanofiber-based biomaterials and nanodevices, but also extend the potential applications in energy storage, cytology, and tissue engineering.

  18. A robust one-compartment fuel cell with a polynuclear cyanide complex as a cathode for utilizing H2O2 as a sustainable fuel at ambient conditions.

    Yamada, Yusuke; Yoneda, Masaki; Fukuzumi, Shunichi


    A robust one-compartment H2O2 fuel cell, which operates without membranes at room temperature, has been constructed by using a series of polynuclear cyanide complexes that contain Fe, Co, Mn, and Cr as cathodes, in sharp contrast to conventional H2 and MeOH fuel cells, which require membranes and high temperatures. A high open-circuit potential of 0.68 V was achieved by using Fe3[{Co(III)(CN)6}2] on a carbon cloth as the cathode and a Ni mesh as the anode of a H2O2 fuel cell by using an aqueous solution of H2O2 (0.30  M, pH 3) with a maximum power density of 0.45 mW cm(-2). The open-circuit potential and maximum power density of the H2O2 fuel cell were further increased to 0.78 V and 1.2 mW cm(-2), respectively, by operation under these conditions at pH 1. No catalytic activity of Co3[{Co(III)(CN)6}2] and Co3[{Fe(III)(CN)6}2] towards H2O2 reduction suggests that the N-bound Fe ions are active species for H2O2 reduction. H2O2 fuel cells that used Fe3[{Mn(III)(CN)6}2] and Fe3[{Cr(III)(CN)6}2] as the cathode exhibited lower performance compared with that using Fe3[{Co(III)(CN)6}2] as a cathode, because ligand isomerization of Fe3[{M(III)(CN)6}2] into (FeM2)[{Fe(II)(CN)6}2] (M = Cr or Mn) occurred to form inactive Fe-C bonds under ambient conditions, whereas no ligand isomerization of Fe3[{Co(III)(CN)6}2] occurred under the same reaction conditions. The importance of stable Fe(2+)-N bonds was further indicated by the high performance of the H2O2 fuel cells with Fe3[{Ir(III)(CN)6}2] and Fe3[{Rh(III)(CN)6}2], which also contained stable Fe(2+)-N bonds. The stable Fe(2+)-N bonds in Fe3[{Co(III)(CN)6}2], which lead to high activity for the electrocatalytic reduction of H2O2, allow Fe3[{Co(III)(CN)6}2] to act as a superior cathode in one-compartment H2O2 fuel cells.

  19. Lipid oxidation in human low-density lipoprotein induced by metmyoglobin/H2O2

    Witting, P K; Willhite, C A; Davies, Michael Jonathan


    Metmyoglobin (metMb) and H(2)O(2) can oxidize low-density lipoprotein (LDL) in vitro, and oxidized LDL may be atherogenic. The role of alpha-tocopherol (alpha-TOH) in LDL oxidation by peroxidases such as metMb is unclear. Herein, we show that during metMb/H(2)O(2)-induced oxidation of native LDL...

  20. Activity and Selectivity for O-2 Reduction to H2O2 on Transition Metal Surfaces

    Siahrostami, Samira; Verdaguer Casadevall, Arnau; Karamad, Mohammadreza;


    Industrially viable electrochemical production of H2O2 requires active, selective and stable electrocatalyst materials to catalyse the oxygen reduction reaction to H2O2. On the basis of density functional theory calculations, we explain why single site catalysts such as Pd/Au show improved select...

  1. Stability of globular proteins in H2O and D2O

    Efimova, Y. M.; Haemers, S.; Wierczinski, B.; Norde, W.; van Well, A. A.


    In several experimental techniques D2O rather then H2O is often used as a solvent for proteins. Concerning the influence of the solvent on the stability of the proteins, contradicting results have been reported in literature. In this paper the influence of H2O-D2O solvent substitution on the stabili

  2. A comparative study on removal of trace nitrobenzene in water by UV/H2O2 and UV/TiO2/H2O2%UV/H2O2和UV/TiO2/H2O2去除水中微量硝基苯的比较研究

    尹菁菁; 张彭义; 孙莉


    研究比较了UV/H2O2和UV/TiO2/H2O2对水中微量硝基苯的降解效果,并考察了水中常见HCO-3和腐殖酸对硝基苯降解的影响.结果表明,薄膜状TiO2的存在对UV/H2O2降解硝基苯有显著的促进作用,在最佳H2O2投加量2.1 mg/L时,UV/TiO2/H2O2的反应速率常数比UV/H2O2高32.8%;2 min内UV/TiO2/H2O2对硝基苯的去除率达到80%以上.HCO-3和腐殖酸对硝基苯降解有很强的抑制作用,HCO-3和腐殖酸浓度分别为2 mmol/L和3.2 mg/L时,UV/TiO2/H2O2对硝基苯的反应速率常数分别下降84.6%和92.2%.

  3. Adsorption of CO2 and H2O on supported amine sorbents

    Veneman, R.; Zhao, W.; Li, Z.; Cai, N.; Brilman, D.W.F.


    In this work we have evaluated the H2O and CO2 adsorption characteristics of Lewatit VP OC 1065 in view of the potential application of solid sorbents in post combustion CO2 capture. Here we present single component adsorption isotherms for H2O and CO2 as well as co-adsorption experiments. It was co

  4. Adsorption of H2O and CO2 on supported amine sorbents

    Veneman, Rens; Frigka, Natalia; Zhao, Wenying; Li, Zhenshan; Kersten, Sascha; Brilman, Wim


    In this work the adsorption of H2O and CO2 on Lewatit VP OC 1065 was studied in view of the potential application of this sorbent in post combustion CO2 capture. Both CO2 and H2O were found to adsorb on the amine active sites present on the pore surface of the sorbent material. However, where the in

  5. Stability of globular proteins in H2O and in D2O

    Efimova, Y.M.; Haemers, S.; Wierczinsky, B.; Norde, W.; Well, van A.A.


    In several experimental techniques D2O rather then H2O is often used as a solvent for proteins. Concerning the influence of the solvent on the stability of the proteins, contradicting results have been reported in literature. In this paper the influence of H2O-D2O solvent substitution on the

  6. Stability of globular proteins in H2O and D2O

    Efimova, Y. M.; Haemers, S.; Wierczinski, B.; Norde, W.; van Well, A. A.


    In several experimental techniques D2O rather then H2O is often used as a solvent for proteins. Concerning the influence of the solvent on the stability of the proteins, contradicting results have been reported in literature. In this paper the influence of H2O-D2O solvent substitution on the

  7. Synthesis and Crystal Structure of a Novel 1D Chain-like Organic Inorganic Hybrid Rare Earth Derivative of Polyoxometalate: H0.5[Sm(H2O)6]0.25[Sm(H2O)5]0.25{[Sm(H2O)7][Sm(H2O)2- (DMSO)] [SiW11O39]}·4.5H2O

    Jun Wei ZHAO; Jing Ping WANG; Jing Yang NIU


    A 1D chain-like organic-inorganic hybrid rare earth derivative of polyoxometalate (DMSO) and characterized by elemental analysis, IR spectra and single crystal X-ray diffraction.The neighboring polyanionic units {[Sm(H2O)7][Sm(H2O)2(DMSO)][SiW11O39]}2- are bridged together to a 1D chain structure by means of [Sm(H2O)2(DMSO)]3+ ion.

  8. Preparation and Performance Analysis of Na2SO4·10H2O/EG Composite Phase-change Materials

    LENG Cong-bin


    Full Text Available Sodium sulfate decahydrate/expanded graphite composite phase-change material (Na2SO4·10H2O/EG was prepared by vacuum adsorption method.The thermal properties of Na2SO4·10H2O/EG,such as melting-solidification,phase separation,supercooling and latent heat were tested and analyzed.The results show that with the addition of 2%(mass fraction borax and 8% EG,the composite phase-change materials Na2SO4·10H2O/EG obtain ideal properties.The phase separation is eliminated,the supercooling degree of Na2SO4·10H2O is reduced from 13.6℃ to below 0.6℃,the latent heat and the energy storage density of the phase-change materials reach 225.77kJ·kg-1 and 218.09MJ·m-3 respectively.The thermal conductivity is also greatly improved.Compared with Na2SO4·10H2O with the addition of the nucleating agent borax only,the time for heat storage is shortened by 52.6%,and the time for heat release is shortened by 55.1%.Even after 500 times of rapid heating and cooling cycles,the performance of Na2SO4·10H2O/EG does not deteriorate.The novel composite phase-change material has better storage/exothermic properties.

  9. Search for sub-millimeter H2O masers in active galaxies - the detection of a 321 GHz H2O maser in NGC4945

    Hagiwara, Yoshiaki; Doi, Akihiro; Miyoshi, Makoto; Edwards, Philip G


    We present further results of a search for extragalactic submillimeter H2O masers using the Atacama Large Millimeter/Submillimeter Array (ALMA). The detection of a 321 GHz H2O maser in the nearby Type 2 Seyfert galaxy, the Circinus galaxy, has previously been reported, and here the spectral analysis of four other galaxies is described. A 321 GHz H2O maser is newly detected toward the center of NGC 4945, a nearby Type 2 Seyfert. The maser shows Doppler-shifted velocity features with velocity ranges similar to those of the 22 GHz H2O maser, however the non-contemporaneous observations also show differences in velocity offsets. The sub-parsec-scale distribution of the 22 GHz H2O masers revealed by earlier VLBI (Very Long Baseline Interferometry) observations suggests that the submillimeter masers could arise in an edge-on rotating disk. The maser features remain unresolved at the synthesized beam of ~0.54 (~30 pc) and are located toward the 321 GHz continuum peak within errors. There is some evidence for a high-...

  10. UV and IR Spectroscopy of Cold H2O(+)-Benzo-Crown Ether Complexes.

    Inokuchi, Yoshiya; Ebata, Takayuki; Rizzo, Thomas R


    The H2O(+) radical ion, produced in an electrospray ion source via charge transfer from Eu(3+), is encapsulated in benzo-15-crown-5 (B15C5) or benzo-18-crown-6 (B18C6). We measure UV photodissociation (UVPD) spectra of the (H2O·B15C5)(+) and (H2O·B18C6)(+) complexes in a cold, 22-pole ion trap. These complexes show sharp vibronic bands in the 35 700-37 600 cm(-1) region, similar to the case of neutral B15C5 or B18C6. These results indicate that the positive charge in the complexes is localized on H2O, giving the forms H2O(+)·B15C5 and H2O(+)·B18C6, in spite of the fact that the ionization energy of B15C5 and B18C6 is lower than that of H2O. The formation of the H2O(+) complexes and the suppression of the H3O(+) production through the reaction of H2O(+) and H2O can be attributed to the encapsulation of hydrated Eu(3+) clusters by B15C5 and B18C6. On the contrary, the main fragment ions subsequent to the UV excitation of these complexes are B15C5(+) and B18C6(+) radical ions; the charge transfer occurs from H2O(+) to B15C5 and B18C6 after the UV excitation. The position of the band origin for the H2O(+)·B18C6 complex (36323 cm(-1)) is almost the same as that for Rb(+)·B18C6 (36315 cm(-1)); the strength of the intermolecular interaction of H2O(+) with B18C6 is similar to that of Rb(+). The spectral features of the H2O(+)·B15C5 complex also resemble those of the Rb(+)·B15C5 ion. We measure IR-UV spectra of these complexes in the CH and OH stretching region. Four conformers are found for the H2O(+)·B15C5 complex, but there is one dominant form for the H2O(+)·B18C6 ion. This study demonstrates the production of radical ions by charge transfer from multivalent metal ions, their encapsulation by host molecules, and separate detection of their conformers by cold UV spectroscopy in the gas phase.

  11. H2 O2-induced higher order chromatin degradation: A novel mechanism of oxidative genotoxicity

    Gregory W Konat


    The genotoxicity of reactive oxygen species (ROS) is well established. The underlying mechanism involves oxidation of DNA by ROS. However, we have recently shown that hydrogen peroxide (H2O2), the major mediator of oxidative stress, can also cause genomic damage indirectly. Thus, H2O2 at pathologically relevant concentrations rapidly induces higher order chromatin degradation (HOCD), i.e. enzymatic excision of chromatin loops and their oligomers at matrix-attachment regions. The activation of endonuclease that catalyzes HOCD is a signalling event triggered specifically by H2O2. The activation is not mediated by an influx of calcium ions, but resting concentrations of intracellular calcium ions are required for the maintenance of the endonuclease in an active form. Although H2O2-induced HOCD can efficiently dismantle the genome leading to cell death, under sublethal oxidative stress conditions H2O2-induced HOCD may be the major source of somatic mutations.

  12. Detection of local H2O exposed at the surface of Ceres

    Combe, Jean-Philippe; McCord, Thomas B.; Tosi, Federico; Ammannito, Eleonora; Carrozzo, Filippo Giacomo; De Sanctis, Maria Cristina; Raponi, Andrea; Byrne, Shane; Landis, Margaret E.; Hughson, Kynan H. G.; Raymond, Carol A.; Russell, Christopher T.


    The surface of dwarf planet Ceres contains hydroxyl-rich materials. Theories predict a water ice-rich mantle, and water vapor emissions have been observed, yet no water (H2O) has been previously identified. The Visible and InfraRed (VIR) mapping spectrometer onboard the Dawn spacecraft has now detected water absorption features within a low-illumination, highly reflective zone in Oxo, a 10-kilometer, geologically fresh crater, on five occasions over a period of 1 month. Candidate materials are H2O ice and mineral hydrates. Exposed H2O ice would become optically undetectable within tens of years under current Ceres temperatures; consequently, only a relatively recent exposure or formation of H2O would explain Dawn’s findings. Some mineral hydrates are stable on geological time scales, but their formation would imply extended contact with ice or liquid H2O.

  13. Copernicus observational searches for OH and H2O in diffuse clouds

    Smith, W. H.; Snow, T. P., Jr.


    An intensive search for OH and H2O in the directions of sigma Sco, alpha Cam, and micron Per was undertaken with the Copernicus satellite. Multiple scans were carried out over the wavelength region for the expected absorption features due to the OH D-X and H2O C-X transitions. The feature due to OH was detected marginally towards sigma Sco, and only an upper limit can be given towards alpha Cam. H2O was not detected in any of the stars at the signal level accumulated. The OH abundance towards sigma Sco and the respective lower limits for the OH/H2O ratios are discussed with regard to the extant models for the steady state abundances of OH and H2O, and shown not to be inconsistent with ion-molecule schemes.

  14. Search Directions for Direct H2O2 Synthesis Catalysts Starting from Au-12 Nanoclusters

    Grabow, Lars; Larsen, Britt Hvolbæk; Falsig, Hanne


    We present density functional theory calculations on the direct synthesis of H2O2 from H-2 and O-2 over an Au-12 corner model of a gold nanoparticle. We first show a simple route for the direct formation of H2O2 over a gold nanocatalyst, by studying the energetics of 20 possible elementary...... that the rate of H2O2 and H2O formation can be determined from a single descriptor, namely, the binding energy of oxygen (E-O). Our model predicts the search direction starting from an Au-12 nanocluster for an optimal catalyst in terms of activity and selectivity for direct H2O2 synthesis. Taking also stability...

  15. the Treatment Effect of γ-rays Combined with H2O2 on Sludge Filtrate

    ZHANG Hao-jia


    Full Text Available The sludge filtrate was performed by 60Co γ-rays irradiation and additive of hydrogen peroxide (H2O2. Effects of initial pH, initial H2O2 concentration and radiation dose on irradiation degradation efficiency were studied by analyzing the change of CODCr、 UV/V is absorbance and turbidity before and after irradiation. The results indicated that the CODCr was removed more easily at the acidic condition under the same dose and initial H2O2 concentration. Gamma irradiation and H2O2 had a significant synergistic effect. When the absorbed dose was 18.75 kGy, the initial pH was 2 and the concentration of H2O2 was 2 mmol/L, the removal of CODCr and turbidity was 70.4% and 94.9%, respectively

  16. Solubility relations in the ternary system NaCl-CsCl-H2O at 1 atm. 1. Solubilities of halite from 20 to 100 °C

    Chou, I.-Ming; Lee, R.D.


    Solubilities of halite in the ternary system NaCl-CsCl-H2O have been determined by the visual polythermal method at 1 atm from 20 to 100??C along five constant CsCl/(CsCl + H2O) weight ratio lines. These five constant weight ratios are 0.1, 0.2, 0.3, 0.4, and 0.5. The maximum uncertainties in these measurements are ??0.02 wt % NaCl and ??0.15??C. The data along each constant CsCl/(CsCl + H2O) weight ratio line were regressed to a smooth curve. The maximum deviation of the measured solubilities from the smooth curves is 0.06 wt % NaCl. Isothermal solubilities of halite were calculated from smoothed curves at 25, 50, and 75??C.

  17. A facile one-pot synthesis of copper sulfide-decorated reduced graphene oxide composites for enhanced detecting of H2O2 in biological environments.

    Bai, Jing; Jiang, Xiue


    The high levels of H2O2 are closely associated with cancer and progressive neurodegenerative diseases, such as Parkinson's disease. In this study, we developed a novel CuS nanoparticle-decorated reduced graphene oxide-based electrochemical biosensor for the reliable detection of H2O2. The new electrocatalyst, CuS/RGO composites was successfully prepared by heating the mixture of CuCl2 and Na2S aqueous solutions in the presence of PVP-protected graphene oxide at 180 °C. A potential application of CuS/RGO composite-modified electrode as a biosensor to monitor H2O2 has been investigated. The steady-state current response increases linearly with H2O2 concentration from 5 to 1500 μM with a fast response time of less than 2 s. The detection limit (3σ) for determination of H2O2 has been estimated to be 0.27 μM, which was lower than certain enzymes and noble metal nanomaterial-based biosensors. In addition, the study of storage time on the amperometric response of the sensor indicates super stability. Due to these remarkable analytical advantages, the as-made sensor was applied to determine the H2O2 levels in human serum and urine samples and H2O2 released from human cervical cancer cells with satisfactory results. These results demonstrate that this new nanocomposite with the high surface area and electrocatalytic activity is a promising candidate for use as an enhanced electrochemical sensing platform in the design of nonenzymatic biosensors.

  18. In Vivo Monitoring of H2O2 with Polydopamine and Prussian Blue-coated Microelectrode.

    Li, Ruixin; Liu, Xiaomeng; Qiu, Wanling; Zhang, Meining


    In vivo monitoring of hydrogen peroxide (H2O2) in the brain is of importance for understanding the function of both reactive oxygen species (ROS) and signal transmission. Producing a robust microelectrode for in vivo measurement of H2O2 is challenging due to the complex brain environment and the instability of electrocatalysts employed for the reduction of H2O2. Here, we develop a new kind of microelectrode for in vivo monitoring of H2O2, which is prepared by, first, electrodeposition of Prussian blue (PB) onto carbon nanotube (CNT) assembled carbon fiber microelectrodes (CFEs) and then overcoating of the CFEs with a thin membrane of polydopamine (PDA) through self-polymerization. Scanning electron microscopic and X-ray proton spectroscopic results confirm the formation of PDA/PB/CNT/CFEs. The PDA membrane enables PB-based electrodes to show high stability in both in vitro and in vivo studies and to stably catalyze the electrochemical reduction of H2O2. The microelectrode is selective for in vivo measurements of H2O2, interference-free from O2 and other electroactive species coexisting in the brain. These properties, along with good linearity, high biocompatibility, and stability toward H2O2, substantially enable the microelectrode to track H2O2 changes in vivo during electrical stimulation and microinfusion of H2O2 and drug, which demonstrates that the microelectrode could be well suited for in vivo monitoring of dynamic changes of H2O2 in rat brain.

  19. Photodegradation of amoxicillin by catalyzed Fe3+/H2O2 process

    Xiaoming Li; Tingting Shen; Dongbo Wang; Xiu Yue; Xian Liu; Qi Yang; Jianbin Cao; Wei Zheng; Guangming Zeng


    Three oxidation processes of UV-Fe3+(EDTA)/H2O2 (UV:ultraviolet light; EDTA:ethylenediaminetetraacetic acid),UV-Fe3+/H2O2 and Fe3+/H2O2 were simultaneously investigated for the degradation of amoxicillin at pH 7.0.The results indicated that,100% amoxicillin degradation and 81.9% chemical oxygen demand (CODcr) removal could be achieved in the UV-Fe3+ (EDTA)/H2O2 process.The treatment efficiency of amoxicillin and CODcr removal were found to decrease to 59.0% and 43.0% in the UV-Fe3+/H2O2 process;39.6% and 31.3% in the Fe3+/H2O2 process.Moreover,the results of biodegradability (biological oxygen demand (BOD5)/CODCr ratio) revealed that the UV-Fe3+ (EDTA)/H2O2 process was a promising strategy to degrade amoxicillin as the biodegradability of the effluent was improved to 0.45,compared with the cases of UV-Fe3+/H2O2 (0.25) and Fe3+/H2O2 (0.10) processes.Therefore,it could be deduced that EDTA and UV light performed synergetic catalytic effect on the Fe3+/H2O2 process,enhancing the treatment efficiency.The degradation mechanisms were also investigated via UV-Vis spectra,and high performance liquid chromatography-mass spectra.The degradation pathway of amoxicillin was further proposed.

  20. Decolorization of Remazol Brilliant Blue Dye Effluent by Advanced Photo Oxidation Process (H2O2/UV system

    A. S. Mahmoud


    Full Text Available Advanced photo oxidation processes hold great promise for the improved treatment of textile dye effluent. In this study, the effectiveness of a H2O2/UV system for the decolorization of remazol brilliant blue effluent was investigated by examining the optimum conditions for dye removal in two reactors (coil and conventional. The results showed that the coil reactor had a higher temperature profile than the conventional reactor. When the dye was fed into the reactors at 25˚C, UV radiation alone was not effective as the decolorization efficiency of the conventional reactor varied from 0.0 to 12.3%, while that of the coil reactor varied from 0.0 to 7.3%, depending on the residence time used. The effect of UV radiation at 100˚C was also negligible as the maximum decolorization efficiencies were 4.0 and 3.7% for the conventional and the coil reactors, respectively. Increasing the concentration of H2O2 increased decolorization efficiencies of both UV reactors. Dye decolorization also increased with residence time. More than 93% color removal of remazol brilliant blue dye was achieved with a residence time of 56 min and 100% decolorization achieved in 65 min using a H2O2 concentration of 12.50 mL Lˉ1.

  1. Regulation of brain mitochondrial H2O2 production by membrane potential and NAD(P)H redox state.

    Starkov, Anatoly A; Fiskum, Gary


    Mitochondrial production of reactive oxygen species (ROS) at Complex I of the electron transport chain is implicated in the etiology of neural cell death in acute and chronic neurodegenerative disorders. However, little is known regarding the regulation of mitochondrial ROS production by NADH-linked respiratory substrates under physiologically realistic conditions in the absence of respiratory chain inhibitors. This study used Amplex Red fluorescence measurements of H2O2 to test the hypothesis that ROS production by isolated brain mitochondria is regulated by membrane potential (DeltaPsi) and NAD(P)H redox state. DeltaPsi was monitored by following the medium concentration of the lipophilic cation tetraphenylphosphonium with a selective electrode. NAD(P)H autofluorescence was used to monitor NAD(P)H redox state. While the rate of H2O2 production was closely related to DeltaPsi and the level of NAD(P)H reduction at high values of DeltaPsi, 30% of the maximal rate of H2O2 formation was still observed in the presence of uncoupler (p-trifluoromethoxycarbonylcyanide phenylhydrazone) concentrations that provided for maximum depolarization of DeltaPsi and oxidation of NAD(P)H. Our findings indicate that ROS production by mitochondria oxidizing physiological NADH-dependent substrates is regulated by DeltaPsi and by the NAD(P)H redox state over ranges consistent with those that exist at different levels of cellular energy demand.

  2. H2O2, H2O and HDO thermal mapping on Mars using TEXES/IRTF and EXES/SOFIA

    Encrenaz, T.; Greathouse, T.; Richter, M.; Lacy, J.; Fouchet, T.; Bézard, B.; Lefèvre, F.; Montmessin, F.; Atreya, S.


    Ever since the Viking era, hydrogen peroxide has been suggested as a possible oxidizer of the Mars surface [1]. H2O2 was first detected in the submillimeter range [2], then regularly monitored, simultaneously with HDO, using high-resolution imaging spectroscopy at 8 μm with TEXES at IRTF [3]. Comparison with the Global Climate Models (GCM) shows that the observations favor the simulations taking into account heterogeneous chemistry [4]. New observations have been performed on H2O2 and HDO with TEXES at IRTF in February 2014, and on H2O and HDO with EXES on SOFIA in April 2014. The latter dataset, obtained near summer solstice, will be used to build a map of D/H on Mars.

  3. Equations of state for H2, H2O, and H2-H2O fluid mixtures at temperatures above 0.01° C and at high pressures

    Rimbach, Helmut; Chatterjee, Niranjan D.


    Modified Redlich-Kwong (MRK) equations of state have been derived for the pure fluid species H2 and H2O by expressing the parameter a as a function of T and P, and b as as a function of P only. These equations are valid above 0° and 0.01° C, respectively. For H2O, the prediction of volumes is successful not only in the supercritical, but also in the subcritical range. As a result of this, the saturation curve of H2O can be calculated with a maximum deviation of ±1.4 bar in the range 100 350° C. Between 350° C and the critical point (374.15° C), the uncertainty increases somewhat; this is due to a fundamental inadequacy of the Redlich-Kwong equation itself. These equations of state permit extrapolations to pressures of 100 kbar for H2 and at least 200 kbar for H2O and are, therefore, eminently suited for geochemical applications. Formulation of the MRK of the binary H2-H2O mixtures was achieved by assuming the quadratic mixing rule for the parameters a mix and b+mix. To derive the cross coefficients, aH2-H2Oand b H 2-H 2O, adjustable corrective factors ɛ and τ had to be introduced. The T- and P-dependences of ɛ and τ are based on P-V-T-X H 2 data (Seward and Franck 1981) to 440° C and 2500 bar. The resulting equation of state very satisfactorily reproduces the volumes observed experimentally at various sets of T, P, and X H 2. At a total pressure of 2 kbar, positive deviation from ideal mixing behaviour is still perceptible at as high a temperature as 1000° C. At some temperature around 380° C, phase separation sets in, an aqueous solution with dissolved H2 coexisting in equilibrium with an H2-rich fluid with dissolved H2O. The computed P-T-X H 2 surface of this two-phase region agrees well with that observed in Seward and Franck's (1981) experiments. An independent proof of the validity of this equation of state is the accuracy with which H {m/ex}can be predicted. Calorimetric measurements of H {m/ex}(Smith et al. 1983, Wormald and Colling 1985

  4. Robust Photocatalytic H2O2 Production by Octahedral Cd3(C3N3S3)2 Coordination Polymer under Visible Light

    Zhuang, Huaqiang; Yang, Lifang; Xu, Jie; Li, Fuying; Zhang, Zizhong; Lin, Huaxiang; Long, Jinlin; Wang, Xuxu


    Herein, we reported a octahedral Cd3(C3N3S3)2 coordination polymer as a new noble metal-free photocatalyst for robust photocatalytic H2O2 production from methanol/water solution. The coordination polymer can give an unprecedented H2O2 yield of ca. 110.0 mmol • L-1 • g-1 at pH = 2.8 under visible light illumination. The characterization results clearly revealed that the photocatalytic H2O2 production proceeds by a pathway of two-electron reduction of O2 on the catalyst surface. This work showed the potential perspective of Mx(C3N3S3)y (M = transitional metals) coordination polymers as a series of new materials for solar energy storage and conversion.

  5. Synthesis, Structure and Characterization of Two-dimensional Network Copper Complex [ Cu3 (nta) 2(azpy) 2(H2O)2]· 6H2O

    LI,Bao-Long(李宝龙); XU,Yan(徐艳); LIU,Qi(刘琦); WANG,Hua-Qin(王化勤); XU,Zheng(徐正)


    The copper(Ⅱ) complex [Cu3(nta)2(azpy)2(H2O)2] @6H2O(nta= nitrilotriacetate, azpy= 4,4'-azobispyridine) has been synthesized and characterized. The X-ray analysis reveals that there are two kinds of copper(Ⅱ) coordination environments.Cu(1) has a distorted square plane symmetry and Cu(2) has a distorted octahedral symmetry. Cu(1)is linked to Cu(2)through nta and bound to Cu(1C) by azpy, and Cu(2) islinked to Cu(2A) through azpy, which extends to two-dimensional network with large rhombus 1.2 nm× 1.7 nm.

  6. Kinetics of the atrazine degradation process using H2O2-UVC.

    Sarmento, Sandra M; Miranda, José T G


    This work is concerned with the intrinsic reaction kinetic of the degradation of atrazine (ATZ) using H2O2-UVC. Experimental runs were carried out in annular photoreactor. The initial concentration of ATZ was 2.2 × 10(-2) mol m(-3) while the H2O2-ATZ molar ratio range was 0-578 mol H2O2 mol(-1) ATZ. The ATZ molecules are decomposed by means of free-radical attack (95.2%) and direct photolysis (4.8%). There is an optimal H2O2/ATZ molar ratio (ROP = 347 H2O2 mol(-1) ATZ) which maximizes the initial degradation rate and conversion at 300 s at 83% and 77%, respectively. The process is economically feasible as the values of the energy requirement, energy and H2O2 costs at ROP are 0.14 KWh m(-3) order(-1), US$0.02 kWh(-1) m(-3) and US$1.0 m(-3), respectively. The kinetic model proposed is based on Lea's reaction scheme for the H2O2 direct photolysis, the hypothesis that unknown ATZ sub-products that absorb UVC radiation are generated, and the local volumetric rate of photon absorption. The radiation transport equation was solved and the linear spherical source emission model was used to represent the lamp emission. Intrinsic reaction kinetic parameters were estimated and the model was validated. The model predicted the data in a range of 90 to 98%.

  7. Cross talk between H2O2 and interacting signal molecules under plant stress response

    Ina eSaxena


    Full Text Available It is well established that oxidative stress is an important cause of cellular damage. During stress condition plants have evolved regulatory mechanism to adapt to various environmental stresses. One of the consequences of stress is an increase in the cellular concentration of ROS, which is subsequently converted to H2O2. H2O2 is continuously produced as the by-product of oxidative plant aerobic metabolism. Organelles with a high oxidizing metabolic activity or with an intense rate of electron flow, such as chloroplasts, mitochondria, or peroxisomes are major sources of H2O2 production. H2O2 acts as a versatile molecule because of its dual role in cells. Under normal conditions, H2O2 acts as a key regulator of many biological processes because H2O2 has been identified as an important second messenger in signal transduction networks. In this review we discuss potential roles of H2O2 and other signaling molecule during various stress responses.

  8. Ion desorption from frozen H 2O irradiated by MeV heavy ions

    Collado, V. M.; Farenzena, L. S.; Ponciano, C. R.; Silveira, E. F. da; Wien, K.


    Nitrogen (0.13-0.85 MeV) and 252Cf fission fragments (˜65 MeV) beams are employed to sputter positive and negative secondary ions from frozen water. Desorption yields are measured for different ice temperatures and projectile energies. Target surface is continuously refreshed by condensed water while the target temperature varies and ice thickness changes. In both projectile energy ranges, the preferentially ejected ions are H +, H2+ and (H 2O) nH +-cluster ions. The yields of the corresponding negative ions H - and (H 2O) nO - or (H 2O) nOH - are 1-2 orders of magnitude lower. The (H 2O) nH + desorption yields decrease exponentially as the cluster size, n, increases. In the low energy range, the desorption of positive ion clusters may occur in a two-step process: first, desorption of preformed H 2O clusters and, then, ionization by H + or H 3O + capture. For 0.81 MeV N + projectile ions, the cluster ion emission contributes with 0.05% to the total H 2O desorbed yield. There are indications that emission of the (H 2O) nH + disappears for an electronic energy loss lower than 20 eV/Å. For the high energy range, desorption of small ion clusters is particularly enhanced, revealing that a fragmentation process also exists.

  9. Optical Absorption and Photo-Thermal Conversion Properties of CuO/H2O Nanofluids.

    Wang, Liangang; Wu, Mingyan; Wu, Daxiong; Zhang, Canying; Zhu, Qunzhi; Zhu, Haitao


    Stable CuO/H2O nanofluids were synthesized in a wet chemical method. Optical absorption property of CuO/H2O nanofluids was investigated with hemispheric transmission spectrum in the wavelength range from 200 nm to 2500 nm. Photo-thermal conversion property of the CuO/H2O nanofluids was studied with an evaluation system equipped with an AUT-FSL semiconductor/solid state laser. The results indicate that CuO/H2O nanofluids have strong absorption in visible light region where water has little absorption. Under the irradiation of laser beam with a wavelength of 635 nm and a power of 0.015 W, the temperature of CuO/H2O nanofluids with 1.0% mass fraction increased by 5.6 °C within 40 seconds. Furthermore, the temperature elevation of CuO/H2O nanofluids was proved to increase with increasing mass fractions. On the contrast, water showed little temperature elevation under the identical conditions. The present work shows that the CuO/H2O nanofluids have high potential in the application as working fluids for solar utilization purpose.

  10. Salidroside Stimulates Mitochondrial Biogenesis and Protects against H2O2-Induced Endothelial Dysfunction

    Xing, Shasha; Yang, Xiaoyan; Li, Wenjing; Bian, Fang; Wu, Dan; Chi, Jiangyang; Xu, Gao; Zhang, Yonghui; Jin, Si


    Salidroside (SAL) is an active component of Rhodiola rosea with documented antioxidative properties. The purpose of this study is to explore the mechanism of the protective effect of SAL on hydrogen peroxide- (H2O2-) induced endothelial dysfunction. Pretreatment of the human umbilical vein endothelial cells (HUVECs) with SAL significantly reduced the cytotoxicity brought by H2O2. Functional studies on the rat aortas found that SAL rescued the endothelium-dependent relaxation and reduced superoxide anion (O2∙−) production induced by H2O2. Meanwhile, SAL pretreatment inhibited H2O2-induced nitric oxide (NO) production. The underlying mechanisms involve the inhibition of H2O2-induced activation of endothelial nitric oxide synthase (eNOS), adenosine monophosphate-activated protein kinase (AMPK), and Akt, as well as the redox sensitive transcription factor, NF-kappa B (NF-κB). SAL also increased mitochondrial mass and upregulated the mitochondrial biogenesis factors, peroxisome proliferator-activated receptor gamma-coactivator-1alpha (PGC-1α), and mitochondrial transcription factor A (TFAM) in the endothelial cells. H2O2-induced mitochondrial dysfunction, as demonstrated by reduced mitochondrial membrane potential (Δψm) and ATP production, was rescued by SAL pretreatment. Taken together, these findings implicate that SAL could protect endothelium against H2O2-induced injury via promoting mitochondrial biogenesis and function, thus preventing the overactivation of oxidative stress-related downstream signaling pathways. PMID:24868319

  11. Peroxiredoxin-2 and STAT3 form a redox relay for H2O2 signaling.

    Sobotta, Mirko C; Liou, Willy; Stöcker, Sarah; Talwar, Deepti; Oehler, Michael; Ruppert, Thomas; Scharf, Annette N D; Dick, Tobias P


    Hydrogen peroxide (H(2)O(2)) acts as a signaling messenger by oxidatively modifying distinct cysteinyl thiols in distinct target proteins. However, it remains unclear how redox-regulated proteins, which often have low intrinsic reactivity towards H(2)O(2) (k(app) ∼1-10 M(-1) s(-1)), can be specifically and efficiently oxidized by H(2)O(2). Moreover, cellular thiol peroxidases, which are highly abundant and efficient H(2)O(2) scavengers, should effectively eliminate virtually all of the H(2)O(2) produced in the cell. Here, we show that the thiol peroxidase peroxiredoxin-2 (Prx2), one of the most H(2)O(2)-reactive proteins in the cell (k(app) ∼10(7)-10(8) M(-1) s(-1)), acts as a H(2)O(2) signal receptor and transmitter in transcription factor redox regulation. Prx2 forms a redox relay with the transcription factor STAT3 in which oxidative equivalents flow from Prx2 to STAT3. The redox relay generates disulfide-linked STAT3 oligomers with attenuated transcriptional activity. Cytokine-induced STAT3 signaling is accompanied by Prx2 and STAT3 oxidation and is modulated by Prx2 expression levels.

  12. Theoretical Studies on the Stabilities and Hydrogen Bond Actions of (H2O)n Clusters

    MENG Xiang-Jun; WANG Ke-Cheng; WU Wen-Sheng; LI Bing-Huan; WANG De-Jin


    The stable configurations and hydrogen bond nature of (H2O)n clusters (n = 3~6) have been investigated by the B3LYP method at the 6-31++g** level. Upon calculation, four conclusions have been drawn: (1) In the (H2O)3~5 clusters, cyclic configurations were confirmed to be the most stable. But in the (H2O)3~4 ones, only cyclic configurations could be observed. From n= 5 ((H2O)5 clusters), three-dimensional configuration could be found; (2) In the (H2O)6 clusters, all configurations are inclined to be three-dimensional except the most stable configuration which is cyclic; (3) The stable order of (H2O)6 clusters indicates that it is the arrangement of hydrogen bond that plays a decisive role in the cluster stabilities, the zero-point energy is also important, and cluster stabilities are independent on the number of hydrogen bonds; (4) There exist strong cooperativity and superadditivity in the (H2O)n clusters.

  13. H2O2 dynamics in the malaria parasite Plasmodium falciparum

    Rahbari, Mahsa; Bogeski, Ivan


    Hydrogen peroxide is an important antimicrobial agent but is also crucially involved in redox signaling and pathogen-host cell interactions. As a basis for systematically investigating intracellular H2O2 dynamics and regulation in living malaria parasites, we established the genetically encoded fluorescent H2O2 sensors roGFP2-Orp1 and HyPer-3 in Plasmodium falciparum. Both ratiometric redox probes as well as the pH control SypHer were expressed in the cytosol of blood-stage parasites. Both redox sensors showed reproducible sensitivity towards H2O2 in the lower micromolar range in vitro and in the parasites. Due to the pH sensitivity of HyPer-3, we used parasites expressing roGFP2-Orp1 for evaluation of short-, medium-, and long-term effects of antimalarial drugs on H2O2 levels and detoxification in Plasmodium. None of the quinolines or artemisinins tested had detectable direct effects on the H2O2 homeostasis at pharmacologically relevant concentrations. However, pre-treatment of the cells with antimalarial drugs or heat shock led to a higher tolerance towards exogenous H2O2. The systematic evaluation and comparison of the two genetically encoded cytosolic H2O2 probes in malaria parasites provides a basis for studying parasite-host cell interactions or drug effects with spatio-temporal resolution while preserving cell integrity. PMID:28369083

  14. Salidroside Stimulates Mitochondrial Biogenesis and Protects against H2O2-Induced Endothelial Dysfunction

    Shasha Xing


    Full Text Available Salidroside (SAL is an active component of Rhodiola rosea with documented antioxidative properties. The purpose of this study is to explore the mechanism of the protective effect of SAL on hydrogen peroxide- (H2O2- induced endothelial dysfunction. Pretreatment of the human umbilical vein endothelial cells (HUVECs with SAL significantly reduced the cytotoxicity brought by H2O2. Functional studies on the rat aortas found that SAL rescued the endothelium-dependent relaxation and reduced superoxide anion (O2∙- production induced by H2O2. Meanwhile, SAL pretreatment inhibited H2O2-induced nitric oxide (NO production. The underlying mechanisms involve the inhibition of H2O2-induced activation of endothelial nitric oxide synthase (eNOS, adenosine monophosphate-activated protein kinase (AMPK, and Akt, as well as the redox sensitive transcription factor, NF-kappa B (NF-κB. SAL also increased mitochondrial mass and upregulated the mitochondrial biogenesis factors, peroxisome proliferator-activated receptor gamma-coactivator-1alpha (PGC-1α, and mitochondrial transcription factor A (TFAM in the endothelial cells. H2O2-induced mitochondrial dysfunction, as demonstrated by reduced mitochondrial membrane potential (Δψm and ATP production, was rescued by SAL pretreatment. Taken together, these findings implicate that SAL could protect endothelium against H2O2-induced injury via promoting mitochondrial biogenesis and function, thus preventing the overactivation of oxidative stress-related downstream signaling pathways.

  15. Decoloration Kinetics of Waste Cooking Oil by 60Co γ-ray/H2O2

    Xiang, Yulin; Xiang, Yuxiu; Wang, Lipeng


    In order to decolorize, waste cooking oil, a dark red close to black solution from homes and restaurants, was subjected to 60Co γ-ray/H2O2 treatment. By virtue of UV/Vis spectrophotometric method, the influence of Gamma irradiation to decoloration kinetics and rate constants of the waste cooking oil in the presence of H2O2 was researched. In addition, the influence of different factors such as H2O2 concentration and irradiation dose on the decoloration rate of waste cooking oil was investigated. Results indicated that the decoloration kinetics of waste cooking oil conformed to the first-order reaction. The decoloration rate increased with the increase of irradiation dose and H2O2 concentration. Saponification analysis and sensory evaluation showed that the sample by 60Co γ-ray/H2O2 treatment presented better saponification performance and sensory score. Furthermore, according to cost estimate, the cost of the 60Co γ-ray/H2O2 was lower and more feasible than the H2O2 alone for decoloration of waste cooking oil.

  16. Production of superoxide/H2O2 by dihydroorotate dehydrogenase in rat skeletal muscle mitochondria.

    Hey-Mogensen, Martin; Goncalves, Renata L S; Orr, Adam L; Brand, Martin D


    Dehydrogenases that use ubiquinone as an electron acceptor, including complex I of the respiratory chain, complex II, and glycerol-3-phosphate dehydrogenase, are known to be direct generators of superoxide and/or H2O2. Dihydroorotate dehydrogenase oxidizes dihydroorotate to orotate and reduces ubiquinone to ubiquinol during pyrimidine metabolism, but it is unclear whether it produces superoxide and/or H2O2 directly or does so only indirectly from other sites in the electron transport chain. Using mitochondria isolated from rat skeletal muscle we establish that dihydroorotate oxidation leads to superoxide/H2O2 production at a fairly high rate of about 300pmol H2O2·min(-1)·mg protein(-1) when oxidation of ubiquinol is prevented and complex II is uninhibited. This H2O2 production is abolished by brequinar or leflunomide, known inhibitors of dihydroorotate dehydrogenase. Eighty percent of this rate is indirect, originating from site IIF of complex II, because it can be prevented by malonate or atpenin A5, inhibitors of complex II. In the presence of inhibitors of all known sites of superoxide/H2O2 production (rotenone to inhibit sites in complex I (site IQ and, indirectly, site IF), myxothiazol to inhibit site IIIQo in complex III, and malonate plus atpenin A5 to inhibit site IIF in complex II), dihydroorotate dehydrogenase generates superoxide/H2O2, at a small but significant rate (23pmol H2O2·min(-1)·mg protein(-1)), from the ubiquinone-binding site. We conclude that dihydroorotate dehydrogenase can generate superoxide and/or H2O2 directly at low rates and is also capable of indirect production at higher rates from other sites through its ability to reduce the ubiquinone pool.

  17. Lateral variation of H2O contents in Quaternary Magma of central Northeastern Japan arc

    Miyagi, I.; Matsu'ura, T.; Itoh, J.; Morishita, Y.


    Water plays a key role in the genesis and eruptive mechanisms of subduction zone volcanoes. We estimated bulk rock water content of both frontal and back arc volcanoes from Northeastern Japan arc in order to understand the lateral variation of magmatic H2O contents in the island arc magma. Our analytical targets are the Adachi volcano located near the volcanic front and the Hijiori volcano located on back arc side. In this study, the bulk magmatic H2O content is estimated by a simple mass balance calculation of the chemistry of bulk rock and melt inclusions in phenocrysts; the melt H2O contents of melt inclusions analyzed by SIMS or EPMA are corrected according to the difference in K2O content between melt inclusions and bulk rock. The bulk magmatic H2O we obtained is 8 wt. % or even more for Adachi and is 2-3 wt. % for Hijiori. Thus, the frontal volcano has higher H2O than the back arc volcano. Although our data are opposed to the previous estimation on the lateral variation of H2O contents in Quaternary volcanoes of Northeastern Japan arc (e.g., Sakuyama, 1979), thermodynamic computations using MELTS (Ghiorso and Sack, 1995) suggest that the amount of bulk magmatic H2O we estimated is consistent with petrographical observations. Our data imply a regional characteristics in the type of eruption that the H2O rich frontal volcanoes will erupt explosively and those H2O poor back arc ones will be effusive, which implication is consistent with actual geological observations that volcanoes located on back arc side of the Northeastern Japan arc generally comprise lava flow (e.g., Iwaki, Kanpu, Chokai, Gassan), in contrast to the frontal ones that produced voluminous tephra (e.g., Osorezan, Towada, Narugo, Adachi). This research project has been conducted under the research contract with Nuclear and Industrial Safety Agency (NISA).

  18. Calculation of H2O-NH3-CO2 Vapor Liquid Equilibria at High Concentration Conditions%高浓度H2O-NH3-CO2体系汽液平衡计算

    魏顺安; 张红晶


    A vapor liquid equilibrium model and its related interactive energy parameters based on UNIQUAC model for the H2O-NH3-CO2 system without solid phase at the conditions of temperature from 30℃ to 90℃,pressure from 0.1 MPa to 0.4 MPa, and the maximum NH3 mass fraction up to 0.4 are provided. This model agrees with experimental data well (average relative error < 1%) and is useful for analysis of industrial urea production.

  19. Refinements in an Mg/MgH2/H2O-Based Hydrogen Generator

    Kindler, Andrew; Huang, Yuhong


    Some refinements have been conceived for a proposed apparatus that would generate hydrogen (for use in a fuel cell) by means of chemical reactions among magnesium, magnesium hydride, and steam. The refinements lie in tailoring spatial and temporal distributions of steam and liquid water so as to obtain greater overall energy-storage or energy-generation efficiency than would otherwise be possible. A description of the prior art is prerequisite to a meaningful description of the present refinements. The hydrogen-generating apparatus in question is one of two versions of what was called the "advanced hydrogen generator" in "Fuel-Cell Power Systems Incorporating Mg-Based H2 Generators" (NPO-43554), NASA Tech Briefs, Vol. 33, No. 1 (January 2009), page 52. To recapitulate: The apparatus would include a reactor vessel that would be initially charged with magnesium hydride. The apparatus would exploit two reactions: The endothermic decomposition reaction MgH2-->Mg + H2, which occurs at a temperature greater than or equal to 300 C, and The exothermic oxidation reaction MgH2 + H2O MgO + 2H2, which occurs at a temperature greater than or equal to 330 C.

  20. 竹浆常规三段漂E段添加H2O2

    唐红梅; 庞业娟



  1. High-Velocity H2O Masers Associated Massive Star Formation Regions

    徐烨; 蒋栋荣; 郑兴武; 顾敏峰; 俞志尧; 裴春传


    We report on the results of 12 CO (1-0) emission associated with H2O masers and massive star formation regions to identify high-velocity H2O masers. Several masers have a large blueshift, even up to 120 km.s-1, with respect to the CO peak, but no large redshifted maser appears. This result suggests that high-velocity H2O masers can most probably occur in high mass star-forming regions and quite a number of masers stem from the amplifications of a background source, which may enable those undetectable weak masers to come to an observable level.

  2. Infinite Three-Dimensional Coordination Polymers: Synthesis and Structures of [Cd (4,4'-bpy)2 (H2O)2]n (pic)2n, [Zn (4,4'-bpy)2 (H2O)2 ]n-(pic)2n (H2O)2n, and [Zn (4,4'-bpy)2 (H2O)2]n (4,4'-bpy)n (H2O)n (pic)2n


    Three Complexes of the formula [ Cd (4,4'-bpy)2 (H2O)2 ]n (pic)2n (1), [ Zn (4,4'-bpy)2 (H2O)2 ]n-(pic)2n (H2O)2n (2) and [ Zn (4,4'-bpy)2 (H2O)2 ]n (4,4'-bpy)n (pic)2n (H2O)n (3) ( 4,4'-bpy = 4,4'-bipyridine; pic = picric anion ) have been synthesized and characterized by elemental analysis and single-crystal x-ray diffraction. They all have infinite three-dimensional network structure, crystallizing in the monoclinic space group C2/c (1) and Cc (2,3).

  3. Crystal structures of Na2SeO4·1.5H2O and Na2SeO4·10H2O

    Matthias Weil


    Full Text Available The crystal structures of Na2SeO4·1.5H2O (sodium selenate sesquihydrate and Na2SeO4·10H2O (sodium selenate decahydrate are isotypic with those of Na2CrO4·1.5H2O and Na2XSeO4·10H2O (X = S, Cr, respectively. The asymmetric unit of the sesquihydrate contains two Na+ cations, one SeO4 tetrahedron and one and a half water molecules, the other half being generated by twofold rotation symmetry. The coordination polyhedra of the cations are a distorted monocapped octahedron and a square pyramid; these [NaOx] polyhedra are linked through common edges and corners into a three-dimensional framework structure, the voids of which are filled with the Se atoms of the SeO4 tetrahedra. The structure is consolidated by O—H...O hydrogen bonds between coordinating water molecules and framework O atoms. The asymmetric unit of the decahydrate consists of two Na+ cations, one SeO4 tetrahedron and ten water molecules. Both Na+ cations are octahedrally surrounded by water molecules and by edge-sharing condensed into zigzag chains extending parallel to [001]. The SeO4 tetrahedra and two uncoordinating water molecules are situated between the chains and are connected to the chains through an intricate network of medium-strength O—H...O hydrogen bonds.

  4. Quantum tunneling during interstellar surface-catalyzed formation of water: the reaction H + H$_2$O$_2$ $\\rightarrow$ H$_2$O + OH

    Lamberts, Thanja; Köhn, Andreas; Kästner, Johannes


    The final step of the water formation network on interstellar grain surfaces starting from the H + O$_2$ route is the reaction between H and H$_2$O$_2$. This reaction is known to have a high activation energy and therefore at low temperatures it can only proceed via tunneling. To date, however, no rate constants are available at temperatures below 200 K. In this work, we use instanton theory to compute rate constants for the title reaction with and without isotopic substitutions down to temperatures of 50 K. The calculations are based on density functional theory, with additional benchmarks for the activation energy using unrestricted single-reference and multireference coupled-cluster single-point energies. Gas-phase bimolecular rate constants are calculated and compared with available experimental data not only for H + H$_2$O$_2$ $\\rightarrow$ H$_2$O + OH, but also for H + H$_2$O$_2$ $\\rightarrow$ H$_2$ + HO$_2$. We find a branching ratio where the title reaction is favored by at least two orders of magnitu...

  5. Nanoparticle formation in H2O/N-2 and H2O/Ar mixtures under irradiation by 20 MeV protons and positive corona discharge

    Imanaka, M.; Tomita, S.; Kanda, S.


    To investigate the contribution of ions to gas nucleation, we have performed experiments on the formation of water droplets in H2O/N-2 and H2O/Ar gas mixtures by irradiation with a 20 MeV proton beam and by positive corona discharge. The size of the formed nanoparticles was measured using a diffe...... positive and negative ions for the formation of nanosize droplets, which attract each other by Coulomb interactions, enhancing the collision frequency and leading to the formation of the 10 nm droplets.......To investigate the contribution of ions to gas nucleation, we have performed experiments on the formation of water droplets in H2O/N-2 and H2O/Ar gas mixtures by irradiation with a 20 MeV proton beam and by positive corona discharge. The size of the formed nanoparticles was measured using...... a differential mobility analyzer equipped with a Faraday cup electrometer. Using the proton beam, droplets around 10 nm in diameter were observed for both positively and negatively charged particles, but none were found when the corona discharge was used. This implies the importance of the presence of both...

  6. A thermodynamic study of 1-propanol-glycerol-H2O at 25 degrees C: Effect of glycerol on molecular organization of H2O

    Parsons, M.T.; Westh, Peter; Davies, J.V.


    The excess chemical potential, partial molar enthalpy, and volume of 1-propanol were determined in ternary mixtures of 1-propanol-glycerol-H2O at 25degreesC. The mole fraction dependence of all these thermodynamic functions was used to elucidate the effect of glycerol on the molecular organization...

  7. H2O and CO2 in magmas from the Mariana arc and back arc systems

    Newman, Sally; Stolper, Edward; Stern, Robert


    We examined the H2O and CO2 contents of glasses from lavas and xenoliths from the Mariana arc system, an intraoceanic convergent margin in the western Pacific, which contains an active volcanic arc, an actively spreading back arc basin, and active behind-the-arc cross-chain volcanoes. Samples include (1) glass rims from Mariana arc, Mariana trough, and cross-chain submarine lavas; (2) glass inclusions in arc and trough phenocrysts; and (3) glass inclusions from a gabbro + anorthosite xenolith from Agrigan (Mariana arc). Glass rims of submarine arc lavas contain 0.3-1.9 wt % H2O, and CO2 is below detection limits. Where they could be compared, glass inclusions in arc phenocrysts contain more H2O than their host glasses; most arc glasses and phenocryst inclusions contain no detectable CO2, with the exception of those from a North Hiyoshi shoshonite, which contains 400-600 ppm. The glass inclusions from the Agrigan xenolith contain 4-6% H2O, and CO2 is below the detection limit. Glasses from the cross-chain lavas are similar to those from the arc: H2O contents are 1.4-1.7 wt %, and CO2 is below detection limits. Volatile contents in Mariana trough lava glass rims are variable: 0.2-2.8 wt % H2O and 0-300 ppm CO2. Glass inclusions from trough phenocrysts have water contents similar to the host glass, but they can contain up to 875 ppm CO2. Volatile contents of melt inclusions from trough and arc lavas and from the xenolith imply minimum depths of crystallization of ~1-8 km. H2O and CO2 contents of Mariana trough glasses are negatively correlated, indicating saturation of the erupting magma with a CO2-H2O vapor at the pressure of eruption (~400 bars for these samples), with the vapor ranging from nearly pure CO2 at the CO2-rich end of the glass array to nearly pure H2O at the H2O-rich end. Degassing of these magmas on ascent and eruption leads to significant loss of CO2 (thereby masking preeruptive CO2 contents) but minimal disturbance of preeruptive H2O contents. For

  8. Supercapacitive performance of hydrous ruthenium oxide (RuO2.H2O) thin films synthesized by chemical route at low temperature

    P R Deshmukh; S N Pusawale; R N Bulakhe; C D Lokhande


    In the present investigation, we report the synthesis of ruthenium oxide (RuO2.H2O) thin films by simple chemical bath deposition (CBD) method at low temperature on the stainless steel substrate. The prepared thin films are characterized for their structural and morphological properties by means of X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT–IR) and scanning electron microscopy (SEM). The structural study revealed that the ruthenium oxide thin films are amorphous. Scanning electron microscopy study shows compact morphology with small overgrown particles on the surface of the substrate. FT–IR study confirms the formation of RuO2.H2O material. The supercapacitor behaviour of RuO2.H2O thin film was studied using cyclic voltammetry (CV) technique in 0.5 M H2SO4 electrolyte. RuO2.H2O film showed maximum specific capacitance of 192 F.g-1 at a scan rate of 20 mV.s-1. The charge–discharge studies of RuO2.H2O carried out at 300 current density revealed the specific power of 1.5 and specific energy of with 95% coulombic efficiency.

  9. Mycorrhiza-induced lower oxidative burst is related with higher antioxidant enzyme activities, net H2O2 effluxes, and Ca2+ influxes in trifoliate orange roots under drought stress.

    Zou, Ying-Ning; Huang, Yong-Ming; Wu, Qiang-Sheng; He, Xin-Hua


    Mechanisms of arbuscular mycorrhiza (AM)-induced lower oxidative burst of host plants under drought stress (DS) are not elucidated. A noninvasive microtest technology (NMT) was used to investigate the effects of Funneliformis mosseae on net fluxes of root hydrogen peroxide (H2O2) and calcium ions (Ca2+) in 5-month-old Poncirus trifoliata, in combination with catalase (CAT) and superoxide dismutase (SOD) activities as well as tissue superoxide radical (O2•-) and H2O2 concentrations under DS and well-watered (WW) conditions. A 2-month DS (55% maximum water holding capacity of growth substrates) significantly inhibited AM fungal root colonization, while AM symbiosis significantly increased plant biomass production, irrespective of water status. F. mosseae inoculation generally increased SOD and CAT activity but decreased O2•- and H2O2 concentrations in leaves and roots under WW and DS. Compared with non-AM seedlings, roots of AM seedlings had significantly higher net H2O2 effluxes and net Ca2+ influxes, especially in the meristem zone, but lower net H2O2 efflux in the elongation zone. Net Ca2+ influxes into roots were significantly positively correlated with root net H2O2 effluxes but negatively with root H2O2 concentrations. Results from this study suggest that AM-induced lower oxidative burst is related with higher antioxidant enzyme activities, root net H2O2 effluxes, and Ca2+ influxes under WW and DS.

  10. In situ cryogenic Raman spectroscopic studies on the synthetic fluid inclusions in the systems H2O and NaCl-H2O


    Salt-hydrates have diagnostic cryogenic Raman spectra, which can reflect the composition of the parent solutions. As analogue to the natural fluid inclusions, the synthetic inclusions can be used to validate numerous assumptions related to fluid inclusion research. They can also be used to test the feasibility of application of laser Raman spectroscopy to individual fluid inclusion analysis. Using the technique proposed by Sterner and Bodnar(1984), synthetic inclusions of the systems H2O and NaCl-H2O (with NaCl as 5.12 wt%, 9.06 wt%, 16.6 wt% and 25 wt%) were formed under the pressures from 50Mpa to 100Mpa and at the temperatures from 500℃ to 600℃. In situ cryogenic Raman spectra were collected at about -180℃ by combined use of freezing- heating stage and Laser Raman Microscopy. It is shown that hydrohalite (NaCl·2H2O), the salt-hydrate of NaCl in the fluid inclusions has the specific Raman spectrum and can be used as the standard to verify the existence of NaCl in the aqueous inclusions. The crystalline ice other than amorphous ice (glasses) formed from the aqueous phase whthin the synthetic inclusions during the initial freezing, but hydrohalite did not form. Subsequent warming of these inclusions induced a phase change, typically between approximately -40 and -22℃, that represents the hydrohalite crystallization event but not a eutectic melting event. So, for fluid inclusions in the system NaCl-H2O, interpretation of phase behavior below the eutectic temperature (-20.8℃) should be made with caution. The ratios of the relative intensity and the area of Raman spectra between 3423 cm-1 peak of hydrohalite and 3098 cm-1 peak of ice show positive correlations to the salinities in aqueous inclusions, which can be used to determine the salinity of NaCl- H2O system inclusions.

  11. Calculation of H2O-NH3-CO2 Vapor Liquid Equilibria at High Concentration Conditions

    魏顺安; 张红晶


    A vapor liquid equilibrium model and its related interactive energy parameters based on UNIQUAC model for the H2O-NH3-CO2 system without solid phase at the conditions of temperature from 30℃ to 90℃, pressure from 0.1 MPa to 0.4 MPa, and the maximum NH3 mass fraction up to 0.4 are provided. This model agrees with experimental data well (average relative error < 1%) and is useful for analysis of industrial urea production.

  12. Structural morphology of gypsum (CaSO 4·2H 2O), brushite (CaHPO 4·2H 2O) and pharmacolite (CaHAsO 4·2H 2O)

    Heijnen, W. M. M.; Hartman, P.


    A uniform description of the crystal structures of gypsum ( CaSO4·2 H2O), brushite ( CaHPO4·2 H2O) and pharmacolite ( CaHAsO4·2 H2O) is presented. From these structures, a PBC analysis leads to the following F forms: {020}, {011}, {⦶1}11 {120} and {⦶1}22 (for brushite and pharmacolite the counterfaces ( ⦶h⦶k⦶l) are included). Attachment energies of the gypsum F faces have been calculated in an electrostatic point charge model for various charge distributions in the water molecule and in the sulphate ion. The theoretical habits are all platy or tabular {020} with {120}, {011} and {⦶1}11, the latter being smaller than {011}, in disagreement with observation. Arguments are given that {011} can grow in layers {built1}/{2}d 011, and therefore faster, at a supersaturation for which {⦶1}11 cannot grow in half layers, thus removing the discrepancy between theory and experiment. The curious triangular or trapeziumlike habit of brushite has been related to its crystal structure. The polar habit is ascribed to different adsorption of water and cosolutes on opposite faces. The most important forms are {020} with {⦶1}20, 11{⦶1} and {111}, the latter being an S form. Its appearance is ascribed to a habit change.

  13. Low-temperature heat capacities and thermodynamic properties of rare-earth triisothiocyanate hydrates (Ⅲ)——Sm(NCS)3·6H2O,Gd(NCS)3·6H2O,Yb(NCS)3·6H2O and Y(NCS)3·6H2O

    谭志诚; Matsuo Takasuke; Suga Hiroshi; 张志英; 尹敬执; 蒋本杲; 孙同山


    The heat capacities of four RE isothiocyanate hydrates,Sm( NCS)3 6H2O,Gd( NCS)3 6H2O,Yb(NCS)3 6H2O and Y( NCS)3 6H2O,have been measured from 13 to 300 K with a fully-automated adiabatic calorimeter No obvious thermal anomaly was observed for the above-mentioned compounds in the experimental tem-peiatnre ranges.The polynomial equations for calculating the heat capacities of the four compounds in the range of 13-300K were obtained by the least-squares fitting based on the experimental Cp data.The Cp values below 13 K were estimated by using the Debye-Einstem heat capacity functions.The standard molar thermodynamic functions were calculated from 0 to 300 K.Gibbs energies of formation were also calculated.

  14. Influence of H2O Rich Fluid Inclusions on Quartz Deformation

    Thust, Anja; Heilbronner, Renée.; Stünitz, Holger; Tarantola, Alexandre; Behrens, Harald


    The effect of H2O on the strength of quartz is well known and has been discussed many times in the literature (e.g. Griggs & Blacic 1965, Kronenberg 1994). In this project we study the H2O interactions between natural dry quartz and H2O rich fluid inclusions during deformation in the solid medium Griggs apparatus. High pressure and temperature experiments were carried out using a quartz single crystal containing a large number of H2O-rich fluid inclusions. Adjacent to the fluid inclusions the crystal is essentially dry (Kronenberg A.K., (1994): Hydrogen specifications and chemical weakening of quartz, Rev. Mineral. Ser. 29 (1994), pp. 123-176.

  15. Characterization and optimization of cathodic conditions for H2O2 synthesis in microbial electrochemical cells

    U.S. Environmental Protection Agency — H2O2_COD_EPA: Measurements of hydrogen peroxide and COD concentrations for water samples from the MEC reactors. MEC_acclimation: raw data for current and voltage of...

  16. 40 CFR 1065.370 - CLD CO2 and H2O quench verification.


    ... analyzer uses quench compensation algorithms that utilize H2O and/or CO2 measurement instruments, evaluate quench with these instruments active and evaluate quench with the compensation algorithms applied....

  17. Photodegradation of Reactive Dyes by UV/Ferrioxalate/H2O2 System

    Wang Binsong(王滨松); Huang Junli; Zhang Jie


    Three types of simulated commercial reactive dye wastewater, separately prepared with FN-2BL red, C-R blue and C-2R yellow, were oxidized with UV/ferrioxalate/H2O2 system, especially by the introduction of Fe2+ ion. The experimental results show that the optimized experimental conditions are pH=3.5, [Fe2+]=1mM, H2O2782mg/L for FN-2BL red and C-R blue and H2O2646mg/L for C-2R yellow, t=4h and T=80℃ when the concentration of dye is 400mg/L. Under such conditions, the observed COD and color removal efficiencies are above 94% and 99%, respectively for all the cases. This investigation has provided fundamental information for the treatment of wastewater containing reactive dyes using UV/ferrioxalate/H2O2.

  18. Degradation of Microcystin-RR by Combination of UV/H2O2 Technique


    The experiments were performed to investigate the degradation of microcystins in order to assess the effectiveness and feasibility of UV/H2O2 system for the disinfection of water polluted by microcystins. The influence factors such as H2O2, pH and UV light intensities were investigated respectively. Degradation of microcystin-RR (MC-RR) could be fitted by either the pseudo-first-order or second-order rate equations. This homogenous system could significantly enhance the degradation rate due to the synergetic effect between UV and H2O2. The degradation mainly followed the mechanism of direct photolysis and .OH oxidation reactions. Experimental results showed that 94.83% of MC-RR was removed under optimal experimental conditions and the UV/H2O2 system provided an alternative to promote the removal of microcystins in drinking water supplies.

  19. H2O: An Autonomic, Resource-Aware Distributed Database System

    Macdonald, Angus; Kirby, Graham


    This paper presents the design of an autonomic, resource-aware distributed database which enables data to be backed up and shared without complex manual administration. The database, H2O, is designed to make use of unused resources on workstation machines. Creating and maintaining highly-available, replicated database systems can be difficult for untrained users, and costly for IT departments. H2O reduces the need for manual administration by autonomically replicating data and load-balancing across machines in an enterprise. Provisioning hardware to run a database system can be unnecessarily costly as most organizations already possess large quantities of idle resources in workstation machines. H2O is designed to utilize this unused capacity by using resource availability information to place data and plan queries over workstation machines that are already being used for other tasks. This paper discusses the requirements for such a system and presents the design and implementation of H2O.

  20. Prevention of H2O2 Induced Oxidative Damages of Rat Testis by Thymus algeriensis

    Fatma Guesmi; Hamida Beghalem; Amit K Tyagi; Manel Ben Ali; Ramla Ben Mouhoub; Houda Bellamine; Ahmed Landoulsi


    ObjectiveWe evaluate the effects ofThymus algeriensis (TEO) against hydrogen peroxide (H2O2) toxicity on body and testis weight, testis sperm count, testis lipid peroxidation, and antioxidant enzyme activities in rats. MethodsRats were treated with low (LD) and high dose (HD) of H2O2 (0.1 and 1 mmol/L) in the presence or absence of TEO (150 mg/kg). ResultsThe results exhibited a significant decrease in body weight and testis weight, in total sperm number decrease (P ConclusionH2O2 has the ability to alter the sperm function, characteristics and development of testis. However, TEO is an efficient natural agent, which can prevent the testis from H2O2-induced oxidative damage in rats.

  1. Formation of Two-dimensional Metal-water Framework Containing (H2O)2O Cluster

    SUN,Ya-Guang; DING,Fu; GU,Xiao-Fu; ZHANG,Wan-Zhong; WEI,De-Zhou; GAO,En-Jun


    [Cd(phen)2(male)(H2O)]·9.5H2O (1) has been synthesized by the reaction of Cd(NO3)2 with phen and male (phen= 1,10-phenanthroline, H2male=maleic acid) in a mixture solvent of ethanol and distilled water. The complex was characterized by elemental analysis, infrared spectrum and thermal gravimetric analyses. The crystal structure was determined by X-ray single-crystal diffraction. In 1, a novel 1D water chain containing water (H2O)20 cluster was formed. Further hydrogen bonding interaction between the water chain and [Cd(phen)2(male)(H2O)] constructs a unique metal-water 2D framework.

  2. An empirical solvus for CO 2-H 2O-2.6 wt% salt

    Hendel, Eva Marie; Hollister, Lincoln S.


    The solvus in the system CO 2-H 2O-2.6 wt% NaCl-equivalent was determined by measuring temperature of homogenization in fluid inclusions which contained variable CO 2/H 2O but the same amount of salt dissolved in the aqueous phase at room temperature. The critical point of the solvus is at 340 ± 5° C, at pressures between 1 and 2 kbar; this is about 65°C higher than for the pure CO 2-H 2O system. The solvus is assymetrical, with a steeper H 2O-rich limb and with the critical point at mole fraction of water between 0.65 and 0.8.

  3. An Infrared Photometric Study of Galaxies with Extragalactic H2O Maser Sources


    All galaxies with extragalactic H2O maser sources observed so far are collected. With the 2MASS and the IRAS photometric data an infrared study is performed on those galaxies. By a comparison between the H2O maser detected sources and non-detected sources in the infrared it is indicated that infrared properties in the IRAS 12-25/μm and 60-100/μm are important for producing H2O masers in galaxies. It is also found that the H2O maser galaxies with different nuclear activity types have rather different infrared properties mainly in the IRAS 12-60/μm region.

  4. HIRDLS/Aura Level 3 Water Vapor (H2O) Zonal Fourier Coefficients V007

    National Aeronautics and Space Administration — The "HIRDLS/Aura Level 3 Water Vapor (H2O) Zonal Fourier Coefficients" version 7 data product (H3ZFCH2O) contains the entire mission (~3 years) of HIRDLS data...

  5. Observations of middle atmospheric H2O and O3 during the 2010 major sudden stratospheric warming by a network of microwave radiometers

    N. Kämpfer


    Full Text Available In this study, we present middle atmospheric water vapor (H2O and ozone (O3 measurements obtained by ground-based microwave radiometers at three European locations in Bern (47° N, Onsala (57° N and Sodankylä (67° N during Northern winter 2009/2010. In January 2010, a major sudden stratospheric warming (SSW occurred in the Northern Hemisphere whose signatures are evident in the ground-based observations of H2O and O3. The observed anomalies in H2O and O3 are mostly explained by the relative location of the polar vortex with respect to the measurement locations. The SSW started on 26 January 2010 and was most pronounced by the end of January. The zonal mean temperature in the middle stratosphere (10 hPa increased by approximately 25 Kelvin within a few days. The stratospheric vortex weakened during the SSW and shifted towards Europe. In the mesosphere, the vortex broke down, which lead to large scale mixing of polar and midlatitudinal air. After the warming, the polar vortex in the stratosphere split into two weaker vortices and in the mesosphere, a new, pole-centered vortex formed with maximum wind speed of 70 m s−1 at approximately 40° N. The shift of the stratospheric vortex towards Europe was observed in Bern as an increase in stratospheric H2O and a decrease in O3. The breakdown of the mesospheric vortex during the SSW was observed at Onsala and Sodankylä as a sudden increase in mesospheric H2O. The following large-scale descent inside the newly formed mesospheric vortex was well captured by the H2O observations in Sodankylä. In order to combine the H2O observations from the three different locations, we applied the trajectory mapping technique on our H2O observations to derive synoptic scale maps of the H2O distribution. Based on our observations and the 3-D wind field, this method allows determining the approximate development of the stratospheric and mesospheric polar vortex and demonstrates the potential of a network of ground

  6. Parameterization of the Absorption of the H2O Continuum, CO2, O2, and Other Trace Gases in the Fu-Liou Solar Radiation Program

    ZHANG Feng; ZENG Qingcun; Y.GU; K.N.LIOU


    The absorption properties of the water vapor continuum and a number of weak bands for H2O, O2, CO2,CO, N2O, CH4, and O3 in the solar spectrum are incorporated into the Fu-Liou radiation parameterization program by using the correlated k-distribution method (CKD) for the sorting of absorption lines. The overlap absorption of the H2O lines and the H2O continuum (2500-14500 cm-1) are treated by taking the two gases as a single-mixture gas in transmittance calculations. Furthermore, in order to optimize the computation efforts, CO2 and CH4 in the spectral region 2850-5250 cm-1 are taken as a new singlemixture gas as well. For overlap involving other absorption lines in the Fu-Liou spectral bands, the authors adopt the multiplication rule for transmittance computations under which the absorption spectra for two gases are assumed to be uncorrelated. Compared to the line-by-line (LBL) computation, it is shown that the errors in fluxes introduced by these two approaches within the context of the CKD method are small and less than 0.48% for the H2O line and continuum in the 2500-14500 cm-1 solar spectral region, ~1% for H2O (line)+H2O (continuum)+CO2+CH4 in the spectral region 2850-5250 cm-1, and ~1.5% for H2O (line)+H2O (continuum)+O2 in the 7700-14500 cm-1 spectral region. Analysis also demonstrates that the multiplication rule over a spectral interval as wide as 6800 cm-1 can produce acceptable errors with a maximum percentage value of about 2% in reference to the LBL calculation. Addition of the preceding gases increases the absorption of solar radiation under all sky conditions. For clear sky, the increase in instantaneous solar absorption is about 9%-13% (~12 W m-2) among which the H2O continuum produces the largest increase, while the contributions from O2 and CO2 rank second and third, respectively. In cloudy sky, the addition of absorption amounts to about 6-9 W m-2. The new, improved program with the incorporation of the preceding gases produces a smaller

  7. Progesterone increases skeletal muscle mitochondrial H2O2 emission in nonmenopausal women.

    Kane, Daniel A; Lin, Chien-Te; Anderson, Ethan J; Kwak, Hyo-Bum; Cox, Julie H; Brophy, Patricia M; Hickner, Robert C; Neufer, P Darrell; Cortright, Ronald N


    The luteal phase of the female menstrual cycle is associated with both 1) elevated serum progesterone (P4) and estradiol (E2), and 2) reduced insulin sensitivity. Recently, we demonstrated a link between skeletal muscle mitochondrial H(2)O(2) emission (mE(H2O2)) and insulin resistance. To determine whether serum levels of P4 and/or E(2) are related to mitochondrial function, mE(H2O2) and respiratory O(2) flux (Jo(2)) were measured in permeabilized myofibers from insulin-sensitive (IS, n = 24) and -resistant (IR, n = 8) nonmenopausal women (IR = HOMA-IR > 3.6). Succinate-supported mE(H2O2) was more than 50% greater in the IR vs. IS women (P < 0.05). Interestingly, serum P4 correlated positively with succinate-supported mE(H2O2) (r = 0. 53, P < 0.01). To determine whether P4 or E2 directly affect mitochondrial function, saponin-permeabilized vastus lateralis myofibers biopsied from five nonmenopausal women in the early follicular phase were incubated in P4 (60 nM), E2 (1.4 nM), or both. P4 alone inhibited state 3 Jo(2), supported by multisubstrate combination (P < 0.01). However, E2 alone or in combination with P4 had no effect on Jo(2). In contrast, during state 4 respiration, supported by succinate and glycerophosphate, mE(H2O2) was increased with P4 alone or in combination with E2 (P < 0.01). The results suggest that 1) P4 increases mE(H2O2) with or without E2; 2) P4 alone inhibits Jo(2) but not when E2 is present; and 3) P4 is related to the mE(H2O2) previously linked to skeletal muscle insulin resistance.

  8. Recent advances in the chemistry of SmI(2)-H(2)O.

    Sautier, Brice; Procter, David J


    Recent work from our laboratories has shown SmI(2)-H(2)O to be a versatile, readily-accessible and non-toxic reductant that is more powerful than SmI(2). This review describes the reduction of functional groups that were previously thought to lie beyond the reach of SmI(2) and complexity-generating cyclisations and cyclisation cascades triggered by the reduction of the ester carbonyl group with SmI(2)-H(2)O.

  9. Detection of hydrogen peroxide (H2O2) in the Martian atmosphere with MEX / PFS

    Aoki, S.; Kasaba, Y.; Giuranna, M.; Geminale, A.; Sindoni, G.; Nakagawa, H.; Kasai, Y.; Murata, I.; Grassi, D.; Formisano, V.


    We first derived the long-term averaged abundance of hydrogen peroxide (H2O2) in the Martian atmosphere with data sets of Planetary Fourier Spectroscopy (PFS) onboard Mars Express (MEX). The total averaged amounts of H2O2 at three Martian years were 45 ± 21 ppb and 25 ± 18 ppb in the forward/reverse pendulum direction, respectively. It could not explain the observed short lifetime of CH4 in the Martian atmosphere.

  10. Ferric and cupric ions requirement for DNA single-strand breakage by H2O2.

    Tachon, P


    Hydrogen peroxide (H2O2), was able to nick the replicative form of the phage fd, without the addition of a reducing agent or of a metal. This DNA single-strand breakage decreased with an increase of the ionic strength, suggesting that H2O2 reacted with traces of metal bound to DNA. When cupric of ferric ions were added, the rate of DNA single-strand breakage by H2O2 greatly increased and it was 20-30 times faster with cupric than with ferric ions. The addition of EDTA at an equimolar ratio or in excess of metal prevented partially DNA single-strand cleavage by H2O2 in the presence of ferric ions and completely when cupric ions were used. Superoxide dismutase prevented DNA single-strand breakage by H2O2 and ferric ions. On the contrary, with cupric ions and H2O2, the addition of superoxide dismutase increased the rate of DNA single-strand breakage. That superoxide dismutase was acting catalytically was shown by the loss of its effects after heat inactivation of the enzyme. The results of the present study show that besides its involvement in the Fenton reaction, H2O2 is able to reduce the metal bound to DNA, generating the superoxide anion radical or/and its protonated form, the perhydroxyl radical involved in DNA nicking. On the other hand, the ability of cuprous ions unlike ferrous ions to dismutate the superoxide radical may explain some differences observed between iron and copper in the DNA single-strand breakage by H2O2.

  11. Main species and chemical pathways in cold atmospheric-pressure Ar + H2O plasmas

    Liu, Dingxin; Sun, Bowen; Iza, Felipe; Xu, Dehui; Wang, Xiaohua; Rong, Mingzhe; Kong, Michael G.


    Cold atmospheric-pressure plasmas in Ar + H2O gas mixtures are a promising alternative to He + H2O plasmas as both can produce reactive oxygen species of relevance for many applications and argon is cheaper than helium. Although He + H2O plasmas have been the subject of multiple experimental and computational studies, Ar + H2O plasmas have received less attention. In this work we investigate the composition and chemical pathways in Ar + H2O plasmas by means of a global model that incorporates 57 species and 1228 chemical reactions. Water vapor concentrations from 1 ppm to saturation (32 000 ppm) are considered in the study and abrupt transitions in power dissipation channels, species densities and chemical pathways are found when the water concentration increases from 100 to 1000 ppm. In this region the plasma transitions from an electropositive discharge in which most power is coupled to electrons into an electronegative one in which most power is coupled to ions. While increasing electronegativity is also observed in He + H2O plasmas, in Ar + H2O plasmas the transition is more abrupt because Penning processes do not contribute to gas ionization and the changes in the electron energy distribution function and mean electron energy caused by the increasing water concentration result in electron-neutral excitation and ionization rates changing by many orders of magnitude in a relatively small range of water concentrations. Insights into the main chemical species and pathways governing the production and loss of electrons, O, OH, OH(A) and H2O2 are provided as part of the study.

  12. Are there Helium-like Protonic States of Individual Water Molecules in Liquid H2O?

    Mueller-Herold, Ulrich


    Are there indications that individual H2O molecules in liquid water can loose their bent structure, i.e. that the protons give up their rigid angular correlation and behave largely uncorrelated, similar to electrons in the ground-state of helium? In agreement with the two-state picture of liquid water this would allow for the thermal coexistence of tetraedrically coordinated and spherical water molecules in the liquid. In the Hooke-Calogero model of a confined triatomic of XY2-type it is shown that energetically low-lying zero orbital-momentum states, which are bent if unconfined can change to helium-like shape under increasing confinement strength f. For the respective states this occurs at different values for f. It turns out that at f = 2.79 a bent and a helium-like state can thermally coexist. In order to characterize more precisely 'helium-like' angular correlation a maximum entropy estimate for the marginal correlation of electrons in the helium ground state is given. KEY WORDS: Liquid water, molecular ...

  13. Photosynthesis of H2O2 and O3 in ASW with ambient O2

    Shi, J.; Raut, U.; Loeffler, M.; Kim, J.; Baragiola, R. A.


    Tenuous O2 atmospheres are known to exist around icy satellites such as Europa and Ganymede and around Saturn’s rings and satellites [1,2]. These faint atmospheres with pressures estimated in 10-3 to 10-8 mbar range [2] are thought to be produced from photolysis and radiolysis of surface ice. In efforts to simulate closely the conditions on icy satellites and grains, ion irradiation of laboratory ices have been performed while maintaining an ambient O2 pressure in recent experiments, which lead to the discovery of the ion-induced O2 adsorption [3]. In the experiments presented here, we investigated the effect of UV photolysis on the ice films in the presence of ambient O2 pressure. Water ice films vapor-deposited between 40 and 100 K were irradiated using 193 nm photons from an ArF Excimer laser, under a constant ambient gas pressure of 7x10-7 mbar. The changes in the film during laser irradiation were monitored using infrared spectroscopy and quartz crystal microgravimetry. At 50 K, we exposed our film to photolysis under ambient pressure of different gas species: Ar, N2 and O2. Interestingly we find enhanced gas absorption only in the presence of ambient O2. In addition, we find that the dangling bond IR absorption disappears, indicating the collapse of micropores. We note that the dangling bond absorption decreases only ~10% in an ice film subject to UV irradiation in the absence of ambient gas, which suggests that the enhanced O2 absorption is not due to gas trapping during compaction [3], but to photo-chemical reactions between OH and transiently adsorbed O2, forming H2O2 and O3, which we detected with IR spectroscopy. We observed that the formation of these two products increases below 50 K, which is explained by increased O2 adsorption at decreasing temperature. Interestingly, if we increase the ambient O2 pressure, then we can increase the maximum temperature for which we can make O3. O3 has not been identified in photolysis of laboratory ice and only

  14. Cosmetic wastewater treatment using the Fenton, Photo-Fenton and H2O2/UV processes.

    Marcinowski, Piotr P; Bogacki, Jan P; Naumczyk, Jeremi H


    Advanced Oxidation Processes (AOPs), such as the Fenton, photo-Fenton and H2O2/UV processes, have been investigated for the treatment of cosmetic wastewaters that were previously coagulated by FeCl3. The Photo-Fenton process at pH 3.0 with 1000/100 mg L(-1) H2O2/Fe(2+) was the most effective (74.0% Chemical Oxygen Demand (COD) removal). The Fenton process with 1200/500 mg L(-1) H2O2/Fe(2+) achieved a COD removal of 72.0%, and the H2O2/UV process achieved a COD removal of 47.0%. Spreading the H2O2 doses over time to obtain optimal conditions did not improve COD removal. The kinetics of the Fenton and photo-Fenton processes may be described by the following equation: d[COD]/dt = -a[COD] t(m) (t represents time and a and m are constants). The rate of COD removal by the H2O2/UV process may be described by a second-order reaction equation. Head Space, Solid-Phase MicroExtraction, Gas Chromatography and Mass Spectrometry (HS-SPME-GC-MS) were used to identify 48 substances in precoagulated wastewater. Among these substances, 26 were fragrances. Under optimal AOP conditions, over 99% of the identified substances were removed in 120 min.

  15. Photometric Measurements of H2O Ice Crystallinity on Trans-Neptunian Objects

    Terai, Tsuyoshi; Oasa, Yumiko; Furusho, Reiko; Watanabe, Junichi


    We present a measurement of H2O ice crystallinity on the surface of trans-neptunian objects (TNOs) with near-infrared narrow-band imaging. The newly developed photometric technique allows us to efficiently determine the strength of an 1.65-um absorption feature in crystalline H2O ice. Our data for three large objects, Haumea, Quaoar, and Orcus, which are known to contain crystalline H2O ice on the surfaces, show a reasonable result with high fractions of the crystalline phase. It can also be pointed out that if the H2O-ice grain size is larger than ~20 um, the crystallinities of these objects are obviously below 1.0, which suggest the presence of the amorphous phase. Especially, Orcus exhibits a high abundance of amorphous H2O ice compared to Haumea and Quaoar, possibly indicating a correlation between bulk density of the bodies and surface crystallization degree. We also found the presence of crystalline H2O ice on Typhon and 2008 AP129, both of which are smaller than the minimum size limit for inducing cryo...

  16. Quantifying Fenton reaction pathways driven by self-generated H2O2 on pyrite surfaces

    Gil-Lozano, C.; Davila, A. F.; Losa-Adams, E.; Fairén, A. G.; Gago-Duport, L.


    Oxidation of pyrite (FeS2) plays a significant role in the redox cycling of iron and sulfur on Earth and is the primary cause of acid mine drainage (AMD). It has been established that this process involves multi-step electron-transfer reactions between surface defects and adsorbed O2 and H2O, releasing sulfoxy species (e.g., S2O32-, SO42-) and ferrous iron (Fe2+) to the solution and also producing intermediate by-products, such as hydrogen peroxide (H2O2) and other reactive oxygen species (ROS), however, our understanding of the kinetics of these transient species is still limited. We investigated the kinetics of H2O2 formation in aqueous suspensions of FeS2 microparticles by monitoring, in real time, the H2O2 and dissolved O2 concentration under oxic and anoxic conditions using amperometric microsensors. Additional spectroscopic and structural analyses were done to track the dependencies between the process of FeS2 dissolution and the degradation of H2O2 through the Fenton reaction. Based on our experimental results, we built a kinetic model which explains the observed trend of H2O2, showing that FeS2 dissolution can act as a natural Fenton reagent, influencing the oxidation of third-party species during the long term evolution of geochemical systems, even in oxygen-limited environments.

  17. Corrosion and time dependent passivation of Al 5052 in the presence of H2O2

    Batmanghelich, Farhad; Hariri, Mohiedin Bagheri; Sharifi-Asl, Samin; Yaghoubinezhad, Yadollah; Mortazavi, Golsa; Seo, Youngwoo


    Corrosion and time-dependent oxide film growth on AA5052 Aluminum alloy in 0.25M Na2SO4 solution containing H2O2 was studied using electrochemical impedance spectroscopy, potentiodynamic polarization, chronoamperometric and open circuit potential monitoring. It was found that sequential addition of H2O2 provokes passivation of AA5052 which ultimately thickens the oxide film and brings slower corrosion rates for AA5052. H2O2 facilitates kinetics of oxide film growth on AA 5052 at 25° and 60 °C which is indicative of formation of a thick barrier film that leads to an increment in the charge transfer resistance. Pitting incubation time increases by introduction of H2O2 accompanied by lower pitting and smoother surface morphologies. At short exposure (up to 8 h) to H2O2-containing solution, the inductive response at low frequencies predominantly determined the corrosion mechanism of AA5052. On the other hand, at prolonged exposure times (more than 24 h) to 0.25M Na2SO4+1vol% H2O2 solution, thicker oxide layers resulted in the mixed inductive-Warburg elements in the spectra.

  18. Adsorption, Diffusion, and Dissociation of H2O on Kaolinite (001): a Density Functional Study

    HE Man-Chao; ZHAO Jian


    Density functional theory is used to investigate the adsorption,diffusion,and dissociation of H2O on kaolinite(001) surface.It is found that the preferred adsorption sites on the kaolinite(001) surface for H2O are the threefold hollow sites with the adsorption energies ranging from 1.06 to 1.15 eV.H2O does not adsorb on the six-fold hollow site of the aluminium(001) face of the third layer of kaolinite,implying that it is difficult for water molecules to penetrate the ideal kaolinite(001) surface.In addition,we calculate the energetic barriers for the diffusion of H2O between the most stable and next most stable adsorption sites,which range from 0.073 to 0.129eV.The results also show that H2O molecules are easy to diffuse on kaolinite(001) surface.Finally,our study indicates that no dissociation state exists for the H2O on kaolinite(001) surface.

  19. H2O2 release from the very long chain acyl-CoA dehydrogenase

    Kakimoto, Pâmela A.H.B.; Tamaki, Fábio K.; Cardoso, Ariel R.; Marana, Sandro R.; Kowaltowski, Alicia J.


    Enhanced mitochondrial generation of oxidants, including hydrogen peroxide (H2O2), is related to a large number of pathological conditions, including diet-induced obesity and steatohepatosis. Indeed, we have previously shown that high fat diets increase the generation of H2O2 in liver mitochondria energized by activated fatty acids. Here, we further study fatty-acid induced H2O2 release in liver mitochondria, and determine the characteristics that regulate it. We find that this production of H2O2 is independent of mitochondrial inner membrane integrity and insensitive to purine nucleotides. On the other hand, palmitate-induced H2O2 production is strongly enhanced by high fat diets and is pH-sensitive, with a peak at a matrix pH of ~8.5. Using recombinantly expressed human very long chain acyl-CoA dehydrogenase, we are able to demonstrate that palmitate-induced H2O2 release may be ascribed to the activity of this enzyme alone, acting as an oxidase. Our results add to a number of findings indicating that sources outside of the electron transport chain can generate significant, physiopathologically relevant, amounts of oxidants in mitochondria. PMID:25728796

  20. H2O2 release from the very long chain acyl-CoA dehydrogenase

    Pâmela A.H.B. Kakimoto


    Full Text Available Enhanced mitochondrial generation of oxidants, including hydrogen peroxide (H2O2, is related to a large number of pathological conditions, including diet-induced obesity and steatohepatosis. Indeed, we have previously shown that high fat diets increase the generation of H2O2 in liver mitochondria energized by activated fatty acids. Here, we further study fatty-acid induced H2O2 release in liver mitochondria, and determine the characteristics that regulate it. We find that this production of H2O2 is independent of mitochondrial inner membrane integrity and insensitive to purine nucleotides. On the other hand, palmitate-induced H2O2 production is strongly enhanced by high fat diets and is pH-sensitive, with a peak at a matrix pH of ~8.5. Using recombinantly expressed human very long chain acyl-CoA dehydrogenase, we are able to demonstrate that palmitate-induced H2O2 release may be ascribed to the activity of this enzyme alone, acting as an oxidase. Our results add to a number of findings indicating that sources outside of the electron transport chain can generate significant, physiopathologically relevant, amounts of oxidants in mitochondria.

  1. H2O2 release from the very long chain acyl-CoA dehydrogenase.

    Kakimoto, Pâmela A H B; Tamaki, Fábio K; Cardoso, Ariel R; Marana, Sandro R; Kowaltowski, Alicia J


    Enhanced mitochondrial generation of oxidants, including hydrogen peroxide (H2O2), is related to a large number of pathological conditions, including diet-induced obesity and steatohepatosis. Indeed, we have previously shown that high fat diets increase the generation of H2O2 in liver mitochondria energized by activated fatty acids. Here, we further study fatty-acid induced H2O2 release in liver mitochondria, and determine the characteristics that regulate it. We find that this production of H2O2 is independent of mitochondrial inner membrane integrity and insensitive to purine nucleotides. On the other hand, palmitate-induced H2O2 production is strongly enhanced by high fat diets and is pH-sensitive, with a peak at a matrix pH of ~8.5. Using recombinantly expressed human very long chain acyl-CoA dehydrogenase, we are able to demonstrate that palmitate-induced H2O2 release may be ascribed to the activity of this enzyme alone, acting as an oxidase. Our results add to a number of findings indicating that sources outside of the electron transport chain can generate significant, physiopathologically relevant, amounts of oxidants in mitochondria. Copyright © 2015 The Authors. Published by Elsevier B.V. All rights reserved.

  2. GPx8 peroxidase prevents leakage of H2O2 from the endoplasmic reticulum.

    Ramming, Thomas; Hansen, Henning G; Nagata, Kazuhiro; Ellgaard, Lars; Appenzeller-Herzog, Christian


    Unbalanced endoplasmic reticulum (ER) homeostasis (ER stress) leads to increased generation of reactive oxygen species (ROS). Disulfide-bond formation in the ER by Ero1 family oxidases produces hydrogen peroxide (H2O2) and thereby constitutes one potential source of ER-stress-induced ROS. However, we demonstrate that Ero1α-derived H2O2 is rapidly cleared by glutathione peroxidase (GPx) 8. In 293 cells, GPx8 and reduced/activated forms of Ero1α co-reside in the rough ER subdomain. Loss of GPx8 causes ER stress, leakage of Ero1α-derived H2O2 to the cytosol, and cell death. In contrast, peroxiredoxin (Prx) IV, another H2O2-detoxifying rough ER enzyme, does not protect from Ero1α-mediated toxicity, as is currently proposed. Only when Ero1α-catalyzed H2O2 production is artificially maximized can PrxIV participate in its reduction. We conclude that the peroxidase activity of the described Ero1α-GPx8 complex prevents diffusion of Ero1α-derived H2O2 within and out of the rough ER. Along with the induction of GPX8 in ER-stressed cells, these findings question a ubiquitous role of Ero1α as a producer of cytoplasmic ROS under ER stress. Copyright © 2014 Elsevier Inc. All rights reserved.

  3. Photometric Measurements of H2O Ice Crystallinity on Trans-Neptunian Objects

    Terai, Tsuyoshi; Itoh, Yoichi; Oasa, Yumiko; Furusho, Reiko; Watanabe, Junichi


    We present a measurement of H2O ice crystallinity on the surface of trans-neptunian objects with near-infrared narrow-band imaging. The newly developed photometric technique allows us to efficiently determine the strength of a 1.65 μm absorption feature in crystalline H2O ice. Our data for three large objects—Haumea, Quaoar, and Orcus—which are known to contain crystalline H2O ice on the surfaces, show a reasonable result with high fractions of the crystalline phase. It can also be pointed out that if the grain size of H2O ice is larger than ˜20 μm, the crystallinities of these objects are obviously below 1.0, which suggests the presence of the amorphous phase. In particular, Orcus exhibits a high abundance of amorphous H2O ice compared to Haumea and Quaoar, possibly indicating a correlation between the bulk density of the bodies and the degree of surface crystallization. We also found the presence of crystalline H2O ice on Typhon and 2008 AP129, both of which are smaller than the minimum size limit for inducing cryovolcanism as well as a transition from amorphous to crystalline phase through thermal evolution due to the decay of long-lived isotopes. Based on data collected at Subaru Telescope, which is operated by the National Astronomical Observatory of Japan (NAOJ).

  4. Production of interstellar hydrogen peroxide (H2O2) on the surface of dust grains

    Du, Fujun; Bergman, Per


    Context. The formation of water on the dust grains in the interstellar medium may proceed with hydrogen peroxide (H2O2) as an intermediate. Recently gas-phase H2O2 has been detected in {\\rho} Oph A with an abundance of ~1E-10 relative to H2. Aims. We aim to reproduce the observed abundance of H2O2 and other species detected in {\\rho} Oph A quantitatively. Methods. We make use of a chemical network which includes gas phase reactions as well as processes on the grains; desorption from the grain surface through chemical reaction is also included. We run the model for a range of physical parameters. Results. The abundance of H2O2 can be best reproduced at ~6E5 yr, which is close to the dynamical age of {\\rho} Oph A. The abundances of other species such as H2CO, CH3OH, and O2 can be reasonably reproduced also at this time. In the early time the gas-phase abundance of H2O2 can be much higher than the current detected value. We predict a gas phase abundance of O2H at the same order of magnitude as H2O2, and an abund...

  5. Proximity-based Protein Thiol Oxidation by H2O2-scavenging Peroxidases*♦

    Gutscher, Marcus; Sobotta, Mirko C.; Wabnitz, Guido H.; Ballikaya, Seda; Meyer, Andreas J.; Samstag, Yvonne; Dick, Tobias P.


    H2O2 acts as a signaling molecule by oxidizing critical thiol groups on redox-regulated target proteins. To explain the efficiency and selectivity of H2O2-based signaling, it has been proposed that oxidation of target proteins may be facilitated by H2O2-scavenging peroxidases. Recently, a peroxidase-based protein oxidation relay has been identified in yeast, namely the oxidation of the transcription factor Yap1 by the peroxidase Orp1. It has remained unclear whether the protein oxidase function of Orp1 is a singular adaptation or whether it may represent a more general principle. Here we show that Orp1 is in fact not restricted to oxidizing Yap1 but can also form a highly efficient redox relay with the oxidant target protein roGFP (redox-sensitive green fluorescent protein) in mammalian cells. Orp1 mediates near quantitative oxidation of roGFP2 by H2O2, and the Orp1-roGFP2 redox relay effectively converts physiological H2O2 signals into measurable fluorescent signals in living cells. Furthermore, the oxidant relay phenomenon is not restricted to Orp1 as the mammalian peroxidase Gpx4 also mediates oxidation of proximal roGFP2 in living cells. Together, these findings support the concept that certain peroxidases harbor an intrinsic and powerful capacity to act as H2O2-dependent protein thiol oxidases when they are recruited into proximity of oxidizable target proteins. PMID:19755417

  6. Proximity-based protein thiol oxidation by H2O2-scavenging peroxidases.

    Gutscher, Marcus; Sobotta, Mirko C; Wabnitz, Guido H; Ballikaya, Seda; Meyer, Andreas J; Samstag, Yvonne; Dick, Tobias P


    H(2)O(2) acts as a signaling molecule by oxidizing critical thiol groups on redox-regulated target proteins. To explain the efficiency and selectivity of H(2)O(2)-based signaling, it has been proposed that oxidation of target proteins may be facilitated by H(2)O(2)-scavenging peroxidases. Recently, a peroxidase-based protein oxidation relay has been identified in yeast, namely the oxidation of the transcription factor Yap1 by the peroxidase Orp1. It has remained unclear whether the protein oxidase function of Orp1 is a singular adaptation or whether it may represent a more general principle. Here we show that Orp1 is in fact not restricted to oxidizing Yap1 but can also form a highly efficient redox relay with the oxidant target protein roGFP (redox-sensitive green fluorescent protein) in mammalian cells. Orp1 mediates near quantitative oxidation of roGFP2 by H(2)O(2), and the Orp1-roGFP2 redox relay effectively converts physiological H(2)O(2) signals into measurable fluorescent signals in living cells. Furthermore, the oxidant relay phenomenon is not restricted to Orp1 as the mammalian peroxidase Gpx4 also mediates oxidation of proximal roGFP2 in living cells. Together, these findings support the concept that certain peroxidases harbor an intrinsic and powerful capacity to act as H(2)O(2)-dependent protein thiol oxidases when they are recruited into proximity of oxidizable target proteins.

  7. Quantification of the production of hydrogen peroxide H2O2 during accelerated wine oxidation.

    Héritier, Julien; Bach, Benoît; Schönenberger, Patrik; Gaillard, Vanessa; Ducruet, Julien; Segura, Jean-Manuel


    Understanding how wines react towards oxidation is of primary importance. Here, a novel approach was developed based on the quantitative determination of the key intermediate H2O2 produced during accelerated oxidation by ambient oxygen. The assay makes use of the conversion of the non-fluorescent Amplex Red substrate into a fluorescent product in presence of H2O2. The total production of H2O2 during 30min was quantified with low within-day and between-day variabilities. Polymerized pigments, but not total polyphenols, played a major role in the determination of H2O2 levels, which were lower in white wines than red wines. H2O2 amounts also increased with temperature and the addition of metal ions, but did not depend on the concentration of many other wine constituents such as SO2. H2O2 levels did not correlate with anti-oxidant properties. We believe that this novel methodology might be generically used to decipher the oxidation mechanisms in wines and food products. Copyright © 2016 Elsevier Ltd. All rights reserved.

  8. Pretreatment with H2O2 Alleviates Aluminum-induced Oxidative Stress in Wheat Seedlings

    Fang Jie Xu; Chong Wei Jin; Wen Jing Liu; Yong Song Zhang; Xian Yong Lin


    Hydrogen peroxide(H2O2)is a key reactive oxygen species(ROS)in signal transduction pathways Ieading to activation of plant defenses against biotic and abiotic stresses.In this study,we investigated the effects of H2O2 pretreatment on aluminum (Al)induced antioxidant responses in root tips of two wheat(Triticum aestivum L.)genotypes,Yangmai-5(Al-sensitive)and Jian-864(Al-tolerant).Al increased and root elongation inhibition in Yangmai-5 than in Jian-864.However,H2O2 pretreatment alleviated Alinduced deleterious effects in both genotypes.Under Al stress,H2O2 pretreatment increased the activities of superoxide dismutase,catalase,peroxidase,ascorbate peroxidase and monodehydroascorbate reductase,glutathione reductase and giutathione peroxidase as well as the levels of ascorbate and glutathione more significantly in Yangmai-5 than in Jian-864.Furthermore,H2O2 pretreatment also increased the total antioxidant capacity evaluated as the 2,2-diphenyl-1-picrylhydrazyl-radical scavenging activity and the ferric reducing/antioxidant power more significantly in Yangmai-5 than in Jian-864.Therefore,we conclude that H2O2 pretreatment improves wheat Al acclimation during subsequent Al exposure by enhancing the antioxidant defense capacity,which prevents ROS accumulation,and that the enhancement is greater in the Al-sensitive genotype than in the Al-tolerant genotype.

  9. Double pancake superconducting coil design for maximum magnetic energy storage in small scale SMES systems

    Hekmati, Arsalan; Hekmati, Rasoul


    Electrical power quality and stability is an important issue nowadays and technology of Superconducting Magnetic Energy Storage systems, SMES, has brought real power storage capability to power systems. Therefore, optimum SMES design to achieve maximum energy with the least length of tape has been quite a matter of concern. This paper provides an approach to design optimization of solenoid and toroid types of SMES, ensuring maximum possible energy storage. The optimization process, based on Genetic Algorithm, calculates the operating current of superconducting tapes through intersection of a load line with the surface indicating the critical current variation versus the parallel and perpendicular components of magnetic flux density. FLUX3D simulations of SMES have been utilized for energy calculations. Through numerical analysis of obtained data, formulations have been obtained for the optimum dimensions of superconductor coil and maximum stored energy for a given length and cross sectional area of superconductor tape.

  10. Microchannel Reactor System Design & Demonstration For On-Site H2O2 Production by Controlled H2/O2 Reaction

    Adeniyi Lawal


    We successfully demonstrated an innovative hydrogen peroxide (H2O2) production concept which involved the development of flame- and explosion-resistant microchannel reactor system for energy efficient, cost-saving, on-site H2O2 production. We designed, fabricated, evaluated, and optimized a laboratory-scale microchannel reactor system for controlled direct combination of H2 and O2 in all proportions including explosive regime, at a low pressure and a low temperature to produce about 1.5 wt% H2O2 as proposed. In the second phase of the program, as a prelude to full-scale commercialization, we demonstrated our H2O2 production approach by ‘numbering up’ the channels in a multi-channel microreactor-based pilot plant to produce 1 kg/h of H2O2 at 1.5 wt% as demanded by end-users of the developed technology. To our knowledge, we are the first group to accomplish this significant milestone. We identified the reaction pathways that comprise the process, and implemented rigorous mechanistic kinetic studies to obtain the kinetics of the three main dominant reactions. We are not aware of any such comprehensive kinetic studies for the direct combination process, either in a microreactor or any other reactor system. We showed that the mass transfer parameter in our microreactor system is several orders of magnitude higher than what obtains in the macroreactor, attesting to the superior performance of microreactor. A one-dimensional reactor model incorporating the kinetics information enabled us to clarify certain important aspects of the chemistry of the direct combination process as detailed in section 5 of this report. Also, through mathematical modeling and simulation using sophisticated and robust commercial software packages, we were able to elucidate the hydrodynamics of the complex multiphase flows that take place in the microchannel. In conjunction with the kinetics information, we were able to validate the experimental data. If fully implemented across the whole

  11. Homogeneous bubble nucleation in H2O- and H2O-CO2-bearing basaltic melts: Results of high temperature decompression experiments

    Le Gall, Nolwenn; Pichavant, Michel


    High pressure and temperature decompression experiments were conducted to provide experimental information on the conditions of homogeneous bubble nucleation in basaltic melts. Experiments were performed on H2O- and H2O-CO2-bearing natural melts from Stromboli. Three starting volatile compositions were investigated: series #1 (4.91 wt% H2O, no CO2), series #2 (2.37-2.45 wt% H2O, 901-1011 ppm CO2) and series #3 (0.80-1.09 wt% H2O, 840-923 ppm CO2). The volatile-bearing glasses were first synthesized at 1200 °C and 200 MPa, and second continuously decompressed in the pressure range 150-25 MPa and rapidly quenched. A fast decompression rate of 78 kPa/s (or 3 m/s) was applied to limit the water loss from the glass cylinder and the formation of a H2O-depleted rim. Post-decompression glasses were characterized texturally by X-ray microtomography. The results demonstrate that homogenous bubble nucleation requires supersaturation pressures (difference between saturation pressure and pressure at which homogeneous bubble nucleation is observed, ∆ PHoN) ≤ 50-100 MPa. ∆ PHoN varies with the dissolved CO2 concentration, from ≪ 50 MPa (no CO2, series #1) to ≤ 50 MPa (872 ± 45 ppm CO2, series #3) to < 100 MPa (973 ± 63 ppm CO2, series #2). In series #1 melts, homogeneous bubble nucleation occurs as two distinct events, the first at high pressure (200 < P < 150 MPa) and the second at low pressure (50 < P < 25 MPa), just below the fragmentation level. In contrast, homogenous nucleation in series #2 and #3 melts is a continuous process. As well, chemical near-equilibrium degassing occurs in the series #1 melts, unlike in the series #2 and #3 melts which retain high CO2 concentrations even for higher vesicularities (up to 23% at 25 MPa). Thus, our experimental observations underline a significant effect of CO2 on the physical mechanisms of bubble vesiculation in basaltic melts. Our experimental decompression textures either reproduce or approach the characteristics of

  12. Two-dimensional dysprosium(III) triiodate(V) dihydrate, Dy(IO3)3(H2O)·H2O

    Chai, Wenxiang; Song, Li; Shi, Hongsheng; Qin, Laishun; Shu, Kangying


    During our research into novel nonlinear optical materials using 1,10-phenanthroline as an appending ligand on lanthanide iodates, crystals of an infinite layered DyIII iodate compound, Dy(IO3)3(H2O)·H2O, were obtained under hydro­thermal conditions. The DyIII cation has a dicapped trigonal prismatic coordination environment consisting of one water O atom and seven other O atoms from seven iodate anions. These iodate anions bridge the DyIII cations into a two-dimensional structure. Through O—H⋯O hydrogen bonds, all of these layers stack along [111], giving a supra­molecular channel, with the solvent water mol­ecules filling the voids. PMID:21583297

  13. An Unsymmetrical Trinickel Metal Complex with 4-Sulfobenzoate Axial Ligand: [Ni3(dpa4(4-sb(H2O]×3H2O

    Xiao-Feng Zheng


    Full Text Available An unsymmetrical trinickel metal complex, [Ni3(dpa4(4-sb(H2O]×3H2O (1, where dpa is a 2,2’-dipyridylamine anion and 4-sb is 4-sulfobenzoate dianion, was synthesized and characterized by X-ray crystallography, IR, elemental analysis, fluorescence, and cyclic voltammetry. The molecular structure of 1 is a cluster with a linear trimer. The extended structure is a 3D architecture assembled by hydrogen bonds. The 4-sulfobenzoate axial replacement leads to the change of Ni-Ni distances, the shift of the fluorescence emission, and the reversible one-electron reduction process without oxidation process.

  14. Low H2O/Ce in Icelandic basalts as evidence for crustal recycling

    Neave, David; Shorttle, Oliver; Hartley, Margaret; Maclennan, John


    The generation of new crust at mid-ocean ridges is balanced by the subduction of partially hydrothermally altered basaltic material back into the mantle. This subducted material may then be recycled and returned via mantle plumes to the Earth's surface at hot spots. Long-identified isotopic and trace element signatures of oceanic crust recycling in ocean island basalts (OIBs) have been recently supplemented by evidence of major element, i.e. lithological, heterogeneity in the melting region. For example, combined major and trace element systematics from Iceland suggest that the mantle source contains at least 5% recycled basalt. Observations of high water (H2O) contents in subglacially quenched basalts from Iceland have previously been attributed to the incorporation of wet recycled material into the mantle source. However, when combined with trace element analyses, recent volatile analyses from the Laki-Grímsvötn and Bárðarbunga-Veiðivötn systems in the Eastern Volcanic Zone (EVZ) of Iceland suggest that the underlying mantle is comparatively depleted in H2O for its degree of major and trace element enrichment. Correlations between H2O and cerium (Ce) within individual mid-ocean ridge basalt (MORB) suites reveal that these elements partition similarly prior to H2O degassing at low pressures; H2O/Ce remains constant during melting and fractionation, and hence reflects the average H2O/Ce of the melting region. MORBs from the Mid-Atlantic Ridge south of Iceland have a mean H2O/Ce value of 304±48 at a mean La/Yb of 2.1±1.5. In contrast, basalts from the EVZ have a lower mean H2O/Ce of 180±20 at a higher mean La/Yb of 3.1±0.5. Thus, despite coming from an enriched section of the Mid-Atlantic ridge in terms of trace element content, basalts from the EVZ have the lowest H2O/Ce values known from the ridge, and are hence comparatively depleted in H2O. Given that H2O/Ce from un-degassed basalts is considered to represent mantle source values, we suggest that low H

  15. Ionization chemistry in the H2O-dominant atmospheres of the icy moons

    Shematovich, V. I.; Johnson, R. E.


    The main pathways of the ionization chemistry for pure H2O- and mixed H2O+O2+CO2+NH3+CH4 atmospheres which are representative for neutral and ionized atmospheres of the icy bodies in the Jovian and Saturnian systems are discussed. The gaseous envelopes of the icy moons of the giant planets are formed usually due to the surface radiolysis by the solar UV radiation and energetic magnetospheric plasma (Johnson, 1990). The standard astrochemical UMIST2005 (UDFA05) network is used to infer the main chemical pathways of ionization chemistry in the pure or with admixtures of other volatile molecules water vapor atmospheres. In case of the H2O- dominant atmosphere the parent H2O molecules are easily dissociated and ionized by the solar UVradiation and the energetic magnetospheric electrons. These impact processes result in the formation of the secondary neutral and ionized products - chemically active radicals O and OH, and H+, H2+, O+, OH+, and H2O+ ions. Secondary ions have admixture abundances in the H2O-dominant atmospheres, because they are efficiently transformed to H3O+ hydroxonium ions in the fast ion-molecular reactions. The major H3O+ hydroxonium ion does not chemically interact with other neutrals, and is destroyed in the dissociative recombination with thermal electrons mainly reproducing the chemically simple H, H2, O, and OH species. In case of the mixed H2O+O2-dominant atmosphere corresponding to the near-surface atmospheres of icy moons (Shematovich et al., 2005), the ionization chemistry results in the formation of the second major ion O2+ - because ion of molecular oxygen has the lower ionization potential comparing with other parent species -H2, H2O, CO2. The H+, O+, OH+, and H2O+ ions can be easily converted to O2+ ions through the ion-molecular reactions. In case of significant admixture of molecular hydrogen it is possible to transfer the O2+ ions to the O2H+ ions through the fast reaction with H2 and further to the H3O+ ions through the ion

  16. The Paradox of a Wet (High H2O) and Dry (Low H2O/Ce) Mantle: High Water Concentrations in Mantle Garnet Pyroxenites from Hawaii

    Peslier, Anne H.; Bizimis, Michael


    Water dissolved as trace amounts in anhydrous minerals has a large influence on the melting behavior and physical properties of the mantle. The water concentration of the oceanic mantle is inferred from the analyses of Mid-Ocean Ridge Basalt (MORB) and Oceanic Island Basalt (OIB). but there is little data from actual mantle samples. Moreover, enriched mineralogies (pyroxenites, eclogites) are thought as important sources of heterogeneity in the mantle, but their water concentrations and their effect on the water budget and cycling in the mantle are virtually unknown. Here, we analyzed by FTIR water in garnet clinopyroxenite xenoliths from Salt Lake Crater, Oahu, Hawaii. These pyroxenites are high-pressure (>20kb) crystal fractionates from alkalic melts. The clinopyroxenes (cpx) have 260 to 576 ppm wt H2O, with the least differentiated samples (Mg#>0.8) in the 400-500 ppm range. Orthopyroxene (opx) contain 117-265 ppm H2O, about half of that of cpx, consistent with other natural sample studies, but lower than cpx/opx equilibrium from experimental data. The pyroxenite cpx and opx H2O concentrations are at the high-end of on-and off-craton peridotite xenolith concentrations and those of Hawaiian spinel peridotites. In contrast, garnet has extremely low water contents (Ce is 69 +/-35, lower than estimates of the MORB source (approx 150) or FOZO, C (200-250) mantle component, but consistent with "dry" EM sources (Ce, and may contribute to EM-type OIB sources, like that of Samoa basalts. Therefore, a low H2O/Ce mantle source may not necessarily be "dry".

  17. Phase diagram prediction of systems Mn(NO3)2-M(NO3)n-H2O(M=Ca,Mg and Li) with modified BET-model

    曾德文; 樊栓狮; 陈四海


    BET-model parameters for the binary system Mn(NO3 )2-H2 O were obtained by fitting experimental water activities at 298.15 K. The values obtained in this work were compared to those fitted previously for the systems Ca(NO3)2-H2O and Zn(NO3)2-H2O, showing reasonable agreement. With the model parameters fitted at 298 K,the vapor pressure of the saturated solution for the phases Mn(NO3 )2 · 6 H2 O and Mn(NO3 )2 · 4 H2 O were predicted and shows quite good agreement with the experimental values. The phase diagram of the Mn(NO2 )2-H2O system reproduced by the BET model shows smaller deviation from the experimental data than that by the extended UNIQUAC model. The ternary phase diagrams of the systems Me(NO3)n-Mn(NO3)2-H2O (Me= Mg, Ca and Li) are predicted with the binary model parameter and compared with available experimental data. The predicted eutectic compositions were given as possible heat storage materials.

  18. Low pressure UV/H2O2 treatment for the degradation of the pesticides metaldehyde, clopyralid and mecoprop - Kinetics and reaction product formation.

    Semitsoglou-Tsiapou, Sofia; Templeton, Michael R; Graham, Nigel J D; Hernández Leal, Lucía; Martijn, Bram J; Royce, Alan; Kruithof, Joop C


    The degradation kinetics of three pesticides - metaldehyde, clopyralid and mecoprop - by ultraviolet photolysis and hydroxyl radical oxidation by low pressure ultraviolet hydrogen peroxide (LP-UV/H2O2) advanced oxidation was determined. Mecoprop was susceptible to both LP-UV photolysis and hydroxyl radical oxidation, and exhibited the fastest degradation kinetics, achieving 99.6% (2.4-log) degradation with a UV fluence of 800 mJ/cm(2) and 5 mg/L hydrogen peroxide. Metaldehyde was poorly degraded by LP-UV photolysis while 97.7% (1.6-log) degradation was achieved with LP-UV/H2O2 treatment at the maximum tested UV fluence of 1000 mJ/cm(2) and 15 mg/L hydrogen peroxide. Clopyralid was hardly susceptible to LP-UV photolysis and exhibited the lowest degradation by LP-UV/H2O2 among the three pesticides. The second-order reaction rate constants for the reactions between the pesticides and OH-radicals were calculated applying a kinetic model for LP-UV/H2O2 treatment to be 3.6 × 10(8), 2.0 × 10(8) and 1.1 × 10(9) M(-1) s(-1) for metaldehyde, clopyralid and mecoprop, respectively. The main LP-UV photolysis reaction product from mecoprop was 2-(4-hydroxy-2-methylphenoxy) propanoic acid, while photo-oxidation by LP-UV/H2O2 treatment formed several oxidation products. The photo-oxidation of clopyralid involved either hydroxylation or dechlorination of the ring, while metaldehyde underwent hydroxylation and produced acetic acid as a major end product. Based on the findings, degradation pathways for the three pesticides by LP-UV/H2O2 treatment were proposed.

  19. Combination of sunlight irradiated oxidative processes for landfill leachate: heterogeneous catalysis (TiO2 versus homogeneous catalysis (H2O2

    Oswaldo Luiz Cobra Guimarães


    Full Text Available The objective of this work was to study the treatment of landfill leachate liquid in nature, after the use of a combination of advanced oxidation processes. More specifically, it compared heterogeneous catalysis with TiO2 to homogeneous catalysis with H2O2, both under photo-irradiated sunlight. The liquid used for the study was the leachate from the landfill of the city of Cachoeira Paulista, São Paulo State, Brazil. The experiments were conducted in a semi-batch reactor open to the absorption of solar UV radiation, with 120 min reaction time. The factors and their respective levels (-1, 0 and 1 were distributed in a experimental design 24-1 with duplicate and triplicate in the central point, resulting in an array with 19 treatment trials. The studied factors in comparing the two catalytic processes were: liquid leachate dilution, TiO2 concentration on the reactor plate, the H2O2 amount and pH level. The leachate had low photo-catalytic degradability, with NOPC reductions ranging from 1% to a maximum of 24.9%. When considering each factor alone, neither homogeneous catalysis with H2O2, nor heterogeneous catalysis with TiO2, could degrade the percolated liquid without significant reductions (5% level in total NOPC. On the other hand, the combined use of homogenous catalysis with H2O2 and heterogeneous catalysis H2O2 resulted in the greatest reductions in NOPC. The optimum condition for the NOPC reduction was obtained at pH 7, dilution of percolated:water at 1:1 (v v-1 rate; excess of 12.5% H2O2 and coating plate reactor with 0.025 g cm-2 TiO2.

  20. Sources of superoxide/H2O2 during mitochondrial proline oxidation

    Renata L.S. Goncalves


    Full Text Available p53 Inducible gene 6 (PIG6 encodes mitochondrial proline dehydrogenase (PRODH and is up-regulated several fold upon p53 activation. Proline dehydrogenase is proposed to generate radicals that contribute to cancer cell apoptosis. However, there are at least 10 mitochondrial sites that can produce superoxide and/or H2O2, and it is unclear whether proline dehydrogenase generates these species directly, or instead drives production by other sites. Amongst six cancer cell lines, ZR75-30 human breast cancer cells had the highest basal proline dehydrogenase levels, and mitochondria isolated from ZR75-30 cells consumed oxygen and produced H2O2 with proline as sole substrate. Insects use proline oxidation to fuel flight, and mitochondria isolated from Drosophila melanogaster were even more active with proline as sole substrate than ZR75-30 mitochondria. Using mitochondria from these two models we identified the sites involved in formation of superoxide/H2O2 during proline oxidation. In mitochondria from Drosophila the main sites were respiratory complexes I and II. In mitochondria from ZR75-30 breast cancer cells the main sites were complex I and the oxoglutarate dehydrogenase complex. Even with combinations of substrates and respiratory chain inhibitors designed to minimize the contributions of other sites and maximize any superoxide/H2O2 production from proline dehydrogenase itself, there was no significant direct contribution of proline dehydrogenase to the observed H2O2 production. Thus proline oxidation by proline dehydrogenase drives superoxide/H2O2 production, but it does so mainly or exclusively by providing anaplerotic carbon for other mitochondrial dehydrogenases and not by producing superoxide/H2O2 directly.

  1. Sources of superoxide/H2O2 during mitochondrial proline oxidation.

    Goncalves, Renata L S; Rothschild, Daniel E; Quinlan, Casey L; Scott, Gary K; Benz, Christopher C; Brand, Martin D


    p53 Inducible gene 6 (PIG6) encodes mitochondrial proline dehydrogenase (PRODH) and is up-regulated several fold upon p53 activation. Proline dehydrogenase is proposed to generate radicals that contribute to cancer cell apoptosis. However, there are at least 10 mitochondrial sites that can produce superoxide and/or H2O2, and it is unclear whether proline dehydrogenase generates these species directly, or instead drives production by other sites. Amongst six cancer cell lines, ZR75-30 human breast cancer cells had the highest basal proline dehydrogenase levels, and mitochondria isolated from ZR75-30 cells consumed oxygen and produced H2O2 with proline as sole substrate. Insects use proline oxidation to fuel flight, and mitochondria isolated from Drosophila melanogaster were even more active with proline as sole substrate than ZR75-30 mitochondria. Using mitochondria from these two models we identified the sites involved in formation of superoxide/H2O2 during proline oxidation. In mitochondria from Drosophila the main sites were respiratory complexes I and II. In mitochondria from ZR75-30 breast cancer cells the main sites were complex I and the oxoglutarate dehydrogenase complex. Even with combinations of substrates and respiratory chain inhibitors designed to minimize the contributions of other sites and maximize any superoxide/H2O2 production from proline dehydrogenase itself, there was no significant direct contribution of proline dehydrogenase to the observed H2O2 production. Thus proline oxidation by proline dehydrogenase drives superoxide/H2O2 production, but it does so mainly or exclusively by providing anaplerotic carbon for other mitochondrial dehydrogenases and not by producing superoxide/H2O2 directly.

  2. The H2O2 scavenger ebselen decreases ethanol-induced locomotor stimulation in mice.

    Ledesma, Juan Carlos; Font, Laura; Aragon, Carlos M G


    In the brain, the enzyme catalase by reacting with H(2)O(2) forms Compound I (catalase-H(2)O(2) system), which is the main system of central ethanol metabolism to acetaldehyde. Previous research has demonstrated that acetaldehyde derived from central-ethanol metabolism mediates some of the psychopharmacological effects produced by ethanol. Manipulations that modulate central catalase activity or sequester acetaldehyde after ethanol administration modify the stimulant effects induced by ethanol in mice. However, the role of H(2)O(2) in the behavioral effects caused by ethanol has not been clearly addressed. The present study investigated the effects of ebselen, an H(2)O(2) scavenger, on ethanol-induced locomotion. Swiss RjOrl mice were pre-treated with ebselen (0-50mg/kg) intraperitoneally (IP) prior to administration of ethanol (0-3.75g/kg; IP). In another experiment, animals were pre-treated with ebselen (0 or 25mg/kg; IP) before caffeine (15mg/kg; IP), amphetamine (2mg/kg; IP) or cocaine (10mg/kg; IP) administration. Following these treatments, animals were placed in an open field to measure their locomotor activity. Additionally, we evaluated the effect of ebselen on the H(2)O(2)-mediated inactivation of brain catalase activity by 3-amino-1,2,4-triazole (AT). Ebselen selectively prevented ethanol-induced locomotor stimulation without altering the baseline activity or the locomotor stimulating effects caused by caffeine, amphetamine and cocaine. Ebselen reduced the ability of AT to inhibit brain catalase activity. Taken together, these data suggest that a decline in H(2)O(2) levels might result in a reduction of the ethanol locomotor-stimulating effects, indicating a possible role for H(2)O(2) in some of the psychopharmacological effects produced by ethanol. Copyright © 2011 Elsevier Ireland Ltd. All rights reserved.

  3. [Degradation of norfloxacin by nano-Fe3O4/H2O2].

    Zhang, Di; Wang, Yi-Xuan; Niu, Hong-Yun; Meng, Zhao-Fu


    The degradation of norfloxacin in aquatic environment was studied in the presence of Fe3O4 nanoparticles and H2O2. The effects of solution pH, temperature, dose of catalysts and concentration of H2O2 on norfloxacin degradation were surveyed. The degradation behaviors of different substrates by nano-Fe3O4/H2O2 were investigated and the reaction mechanism of norfloxacin was discussed. The results showed that the reaction was strongly pH-dependent and favored in acidic solution (pH = 3.5). The removal efficiency of norfloxacin was enhanced with the increase of temperature, catalysts dosage and H2O2 concentration. The degradation efficiency of norfloxacin by nano-Fe3O4/H2O2 was significantly higher than those of sulfathiazole, phenolic and aniline compounds. In the presence of 4.4 mmol x L(-1) of H2O2, 0.80 g x L(-1) of Fe3O4 and T = 303 K, norfloxacin was degraded completely in 5 min. The F element in norfloxacin molecule existed totally as F(-) in solution within 5 min, and the removal efficiency of total organic carbon was 57% in 1 h. In the ESR spectrum of nano-Fe3O4/H2O2 system, the characteristic peaks of BMPO-*OH adduct was detected, however, the intensity of the peaks was reduced to 5% with the addition of tert-butanol, a strong *OH scavenger, and the degradation efficiency of norfloxacin was correspondingly decreased to 10% in 1 h. These results indicated that *OH played an important role on norfloxacin degradation, and the reaction proceeded based on a heterogeneous Fenton-like system.

  4. Rovibrational states of the H2O-H2 complex: An ab initio calculation

    van der Avoird, Ad; Nesbitt, David J.


    All bound rovibrational levels of the H2O-H2 dimer are calculated for total angular momentum J = 0-5 on two recent intermolecular potential surfaces reported by Valiron et al. [J. Chem. Phys. 129, 134306 (2008)] and Hodges et al. [J. Chem. Phys. 120, 710 (2004)] obtained through ab initio calculations. The method used handles correctly the large amplitude internal motions in this complex; it involves a discrete variable representation of the intermolecular distance coordinate R and a basis of coupled free rotor wave functions for the hindered internal rotations and the overall rotation of the dimer. The basis is adapted to the permutation symmetry associated with the para/ortho (p/o) nature of both H2O and H2 as well as to inversion symmetry. Dimers containing oH2 are more strongly bound than dimers with pH2, as expected, with dissociation energies D_0 of 33.57, 36.63, 53.60, and 59.04 cm^{-1}for pH2O-pH2, oH2O-pH2, pH2O-oH2, and oH2O-oH2, respectively, on the potential of Valiron et al. that corresponds to a binding energy D_e of 235.14 cm^{-1}. Rovibrational wave functions are computed as well and the nature of the bound states in the four different dimer species is discussed. Converged rovibrational levels on both potentials agree well with the high-resolution spectrum reported by Weida and Nesbitt [J. Chem. Phys. 110, 156 (1999)]; the hindered internal rotor model that was used to interpret this spectrum is qualitatively correct.

  5. Synthesis and Structural Determination of Nine-Coordinate K[GdIII(edta)(H2O)3]·5H2O


    The title complex K[GdIII(edta)(H2O)3]·5H2O was synthesized, where edta denotes ethylenediamine-tetraacetic acid. The crystal and molecular structure of the complex were determined by single-crystal X-ray structure analysis. The crystal belongs to an orthorhombic crystal system and an Fdd2 space group. The complex anion [GdIII(edta)(H2O)3]- has a pseudo-monocapped square antiprismatic nine-coordinate structure in which six coordinate atoms (two N and four O) are from an edta ligand and three water molecules coordinate to GdIII ion directly. It can be predicted that GdIII ion can also form a nine-coordinate complex with ttha (triethylenetetraminehexaacetic acid) ligand, so the GdIII complex anion [GdIII(Httha)]2- can supply a free non-coordinate carboxyl group used for molecular embellishment in some biological molecules to form a contrast agent of Magnetic Resonance Imagine (MRI) with targeting function.

  6. Crystal Structure of a Threedimensional Coordination Polymer {[Ca3(μ5-OOCCH2OCH2COO)3(H2O)4]·4H2O}n


    A novel three-dimensional coordination polymer, {[Ca3(μ5-OOCCH2OCH2COO)3(H2O)4]·4H2O}n, has been synthesized with oxydiacetate as bridge ligand and structurally determined by X-ray crystallography. The crystal belongs to monoclinic, space group C2/c with a = 17.805(2), b = 9.3923(12), c = 17.255(2)(A), β = 107.838(5)°, V = 2746.8(6) (A)3, Mr = 660.58, C12H28Ca3O23, Dc = 1.597 g/cm3, μ = 0.695 mm-1, Z = 4, F(000) = 1376, GOOF = 1.027, R = 0.0303 and wR = 0.0660. In the complex there are two coordination modes for Ca(Ⅱ) ions, one coordinated by three μ5-OOCCH2OCH2COO2- bridge ligands together with two H2O molecules, and the other by five μ5-OOCCH2OCH2COO2- bridge ligands. In both coordination modes each Ca(Ⅱ) ion assumes a distorted dipentapyramidal CaO7 geometry; whereas each oxydiacetate is coordinated with five Ca(Ⅱ) ions and acts as a pentdentates bridge ligand.

  7. Synthesis and Crystal Structure of a Cyano-bridged Bimetallic Complex: [NdFe(CN)6(DMF)4(H2O)3]·H2O

    李建荣; 郭国聪; 王明盛; 周国伟; 卜显和; 黄锦顺


    A new bimetallic cyano-bridged complex, [NdFe(CN)6(DMF)4(H2O)3]@H2O (DMF= N,N-dimethylformamide) 1, has been obtained by the reaction of hexacyanoferrate potassium with neodymium (Ⅲ) chloride in H2O/EtOH/DMF (volume ratio: 2:2:1), and its structure was determined by means of single-crystal X-ray diffraction. The compound crystallizes in space group P21/n of monoclinic system with cell parameters: a = 17.646(1), b = 8.9011(3), c = 19.945(1) A, β = 95.835(2)°, V= 3116.6(3) A3, Z = 4, Dc = 1.536 g/cm3, Mr = 720.66, F(000) = 1456, μ = 2.166 mm-1, R = 0.0386, wR = 0.1120 and S = 1.061. The central Nd (Ⅲ) ion is coordinated by seven oxygen atoms of four DMF molecules and three water molecules and one nitrogen atom of the bridging cyanide in a slightly distorted square-antiprism arrangement, and the Fe (Ⅲ) ion is in an almost octahedral environment coordinated to six cyano-ligands, of which one cyanide ligand bridges the Nd (Ⅲ) ion to form a bimetallic complex. Molecules of complexes in the crystal lattice are held together by hydrogen bonding, forming a three-dimensional framework.


    Aldes Lesbani


    Full Text Available Senyawa oksotrinuklir telah disintesis menggunakan kromium nitrat dan asam benzoat dalam etanol pada temperatur 80 oC selama 1 jam.Kristal senyawa oksotrinuklir hasil sintesis dikarakterisasi menggunakan spektrofotometer FTIR, 1H NMR padat, X-Ray Difraktometer, TGA, dan MS dengan teknik ionisasi dingin. Hasil penelitian menunjukkan bahwa senyawa oksotrinuklir mempunyai vibrasi yang khas pada bilangan gelombang 671 cm-1(ν Cr3-O. Identifikasi dengan spektrometer massa dalam asetonitril sebagai pelarut menunjukkan fragmentasi pada m/z: 1021.83 [Cr3O(OOCC6H56(MeCN3]+, 998,80 [Cr3O(OOCC6H56(MeCN2(H2O]+, 980,79 [Cr3O(OOCC6H56(MeCN2]+, 939,73 [Cr3O(OOCC6H56(MeCN]+. Puncak yang lebar dan besar pada spektrum 1H NMR menunjukkan bahwa kromium yang bersifat paramagnetic di dalam senyawa. Pola XRD menunjukkan bahwa senyawa oksotrinuklir adalah kristalin dan hasil termogravimetri menunjukkan senyawa oksotrinuklir stabil sampai suhu 174 oC dan mempunyai 5 mol air kristal. Dari hasil karakterisasi FTIR,1H NMR, XRD, TGA, dan MS dapat disimpulkan bahwa senyawa yang terbentuk adalah [Cr3O(OOCC6H56(H2O3](NO3×5H2O.

  9. Calculation of electron detachment energies for water cluster anions: an appraisal of electronic structure methods, with application to (H2O)20- AND (H2O)24-.

    Herbert, John M; Head-Gordon, Martin


    We present benchmark calculations of vertical electron detachment energies (VDEs) for various conformers of (H2O)n-, using both wave function and density functional methods, in sequences of increasingly diffuse Gaussian basis sets. For small clusters (n VDEs. Second-order Møller-Plesset perturbation (MP2) theory suffices to obtain VDEs that are within 0.05 eV of the results from both experiment and coupled-cluster theory, and which always err toward underbinding the extra electron. In contrast to these consistent predictions, VDEs calculated using density functional theory (DFT) vary widely, according to the fraction of Hartree-Fock exchange in a given functional. Common functionals such as BLYP and B3LYP overestimate the VDE by 0.2-0.5 eV, whereas a variant of Becke's "half and half" functional is much closer to coupled-cluster predictions. Exploratory calculations for (H2O)20- and (H2O)24- cast considerable doubt on earlier calculations that were used to assign the photoelectron spectra of these species to particular cluster isomers.

  10. Crystal structure of [Y6(μ6-O(μ3-OH8(H2O24]I8·8H2O

    François Le Natur


    Full Text Available The crystal structure of the title compound {systematic name: octa-μ3-hydroxido-μ6-oxido-hexakis[tetraaquayttrium(III] octaiodide octahydrate}, is characterized by the presence of the centrosymmetric molecular entity [Y6(μ6-O(μ3-OH8(H2O24]8+, in which the six Y3+ cations are arranged octahedrally around a μ6-O atom at the centre of the cationic complex. Each of the eight faces of the Y6 octahedron is capped by an μ3-OH group in the form of a distorted cube. In the hexanuclear entity, the Y3+ cations are coordinated by the central μ6-O atom, the O atoms of four μ3-OH and of four water molecules. The resulting coordination sphere of the metal ions is a capped square-antiprism. The crystal packing is quite similar to that of the orthorhombic [Ln6(μ6-O(μ3-OH8(H2O24]I8·8H2O structures with Ln = La—Nd, Eu—Tb, Dy, except that the title compound exhibits a slight monoclinic distortion. The proximity of the cationic complexes and the lattice water molecules leads to the formation of a three-dimensional hydrogen-bonded network of medium strength.

  11. Synthesis and Crystal Structure of 18-Tungstotetranickel(Ⅱ) diphosphate Nato {(PWgO34)2Nia(H2O)2}·26H2O


    The structure of single crystal of the polyoxotungstate salt Na10{(PWoO34)2Ni4(H2O)2}·26H2O ( Na1oNi4O96P2W18H56, Mr=5371.96) has been determined by X-ray diffraction (MoKα). Crystal data: P21/n, a=11.898(2), b=16.629(4), c=21.413(4)A, β = 100.59(1)°, V= 4164.5(1)A3, Z=2, Dc = 4.284g/cm3, F(000) = 4704,μ =2.5847cm-1, final R = 0.0344, and wR= 0.0804 for 5830 independent reflections. Two B-α-PWgO349-units in the compound are linked via a set of four coplanar Ni2+ atoms, which also carry H2O ligands. The NiO6 octahedra in each centrosymmetric anion are all tetragonally elongated with their long axes parallel.

  12. Synthesis and Structure of a Novel Compound [Cu2(EDTA)(Py)2(H2O)2]·2H2O

    TANG Ding-Xing; ZHAO Yun


    A novel compound [Cu2(EDTA)(Py)2(H2O)2]·2H2O was synthesized by the reaction of CuSO4(5H2O with H4EDTA in pyridine/water (V/V = 1/4) solvent, and characterized by elemental analysis, IR spectrum and X-ray single-crystal diffraction. It crystallizes in the monoclinic system, space group P21/n with a = 1.26974(6), b = 0.67949(3), c = 1.48548(3) nm, β = 91.454(2)o, V = 1.28122(9) nm3, Z = 2, Dc = 1.673 g/cm3, Mr = 645.56, F(000) = 664, μ(MoKα) = 1.729 mm-1, the final R = 0.0353 and wR = 0.0832 for 1920 observed reflections (I > 2((I)). The compound is a centrosymmetric binuclear molecule with bridged EDTA group. Each Cu(II) atom is linked to two oxygen atoms and one nitrogen atom of EDTA, one oxygen atom of water and one nitrogen atom of pyridine to form a distorted square pyramidal environment. There exist face-to-face π-π stacking interactions between pyridine rings from neighboring molecule with the interplanar distance of 0.3670 nm and hydrogen bonding between EDTA and water molecules.

  13. Treatment of Remazol Brilliant Blue Dye Effluent by Advanced Photo Oxidation Process in TiO2/UV and H2O2/UV reactors

    M. Verma


    Full Text Available Advanced oxidation processes involving TiO2/UV and H2O2/UV were evaluated for their potential use in decolorization of textile dye effluents. A coil photo reactor, consisting of UV radiation source and a spiral coil coated with TiO2, was used to treat synthetic effluent of Remazol Brilliant Blue dye. The TiO2 coating was performed using the sol-gel technique. The effects of UV radiation, TiO2 coatings and dye concentration were studied and the results were compared to dye treatment involving H2O2. The maximum dye removal efficiencies were 7.3, 12.2 and 12.5 % for uncoated, single coat and dual coat of TiO2, respectively. The decolorization efficiency was inversely related to dye concentration of the effluent. The treatments with UV only, TiO2 only, UV+TiO2, H2O2 only and UV+H2O2 resulted in color reduction of 7.6, 2.3, 12.5, 4.1 and 99.9 % respectively. The maximum decolorization occurred in ≤ 100 min in all cases. The temperature varied from 29.2 to 54.7°C for UV+TiO2 treatment and no change in reactor temperature was observed when UV was not used.

  14. Differentiating between apparent and actual rates of H2O2 metabolism by isolated rat muscle mitochondria to test a simple model of mitochondria as regulators of H2O2 concentration

    Jason R. Treberg


    Full Text Available Mitochondria are often regarded as a major source of reactive oxygen species (ROS in animal cells, with H2O2 being the predominant ROS released from mitochondria; however, it has been recently demonstrated that energized brain mitochondria may act as stabilizers of H2O2 concentration (Starkov et al. [1] based on the balance between production and the consumption of H2O2, the later of which is a function of [H2O2] and follows first order kinetics. Here we test the hypothesis that isolated skeletal muscle mitochondria, from the rat, are able to modulate [H2O2] based upon the interaction between the production of ROS, as superoxide/H2O2, and the H2O2 decomposition capacity. The compartmentalization of detection systems for H2O2 and the intramitochondrial metabolism of H2O2 leads to spacial separation between these two components of the assay system. This results in an underestimation of rates when relying solely on extramitochondrial H2O2 detection. We find that differentiating between these apparent rates found when using extramitochondrial H2O2 detection and the actual rates of metabolism is important to determining the rate constant for H2O2 consumption by mitochondria in kinetic experiments. Using the high rate of ROS production by mitochondria respiring on succinate, we demonstrate that net H2O2 metabolism by mitochondria can approach a stable steady-state of extramitochondrial [H2O2]. Importantly, the rate constant determined by extrapolation of kinetic experiments is similar to the rate constant determined as the [H2O2] approaches a steady state.

  15. Using mineral equilibria to estimate H2O activities in peridotites from the Western Gneiss Region of Norway

    Kang, Patricia; Lamb, William M.; Drury, Martyn


    The Earth's mantle is an important reservoir of H2O, and even a small amount of H2O has a significant influence on the physical properties of mantle rocks. Estimating the amount of H2O in rocks from the Earth's mantle would, therefore, provide some insights into the physical properties of this

  16. Self-Assembly,Crystal Structure and Magnetic Properties of Three-Dimensional Supramolecular Complex [Ni (hmt)2 (SCN)2 (H2O)2 ] [Ni (SCN)2 (H2O)4 ] (H2O)2 (hmt = hexamethylenetetramine)%三维超分子[Ni(hmt)2(SCN)2(H2O)2][Ni(SCN)2(H2O)4](H2O)2的自组装,晶体结构及磁性质(hmt=六次甲基四胺)

    李纲; 朱玉; 李林科; 侯红卫; 樊耀亭; 杜晨霞


    Compound [Ni(hmt) 2(SCN) 2(H2O) 2] [Ni(SCN) 2(H2O) 4] (H2O) 2 (hmt = hexamethylenetetramine) was prepared and structurally characterized by means of X-ray single crystal diffraction.The two neutral units [Ni(hmt)2variable-temperature magnetic susceptibilities (5 ~ 300K) shows that the magnetic behavior obeys the Curie-Weiss law over the whole temperature ranges.

  17. Treatment of Sulfonated Azo Dye Reactive Red 198 by UV/H2O2

    Jefferson P. Ribeiro


    Full Text Available UV/H2O2 system was tested on the color removal of sulfonated azo dye Reactive Red 198 (RR, which is widely used in textile process. The effects of hydrogen peroxide concentration, temperature, pH, and the in-line addition of hydrogen peroxide on high color and chemical oxygen demand (COD removals were investigated. The kinetic of dye decolorization was also determined. The results showed that 2% H2O2 decreased the process efficiency, while 1% H2O2 solution led to a better performance of the system. Despite the fact that the pH increase had small effect on color removal, it affects positively COD removals. The same behavior was found for temperature increase. A high temperature resulted in a slight decrease in color removal and a sharp decrease for COD removal. In addition the H2O2 in-line provided a small improvement in both color and COD removals. UV/1% H2O2 treatment was the most efficient, the good performance was linked to higher amount of hydroxyl radicals formed.

  18. Catalase and ascorbate peroxidase-representative H2O2-detoxifying heme enzymes in plants.

    Anjum, Naser A; Sharma, Pallavi; Gill, Sarvajeet S; Hasanuzzaman, Mirza; Khan, Ekhlaque A; Kachhap, Kiran; Mohamed, Amal A; Thangavel, Palaniswamy; Devi, Gurumayum Devmanjuri; Vasudhevan, Palanisamy; Sofo, Adriano; Khan, Nafees A; Misra, Amarendra Narayan; Lukatkin, Alexander S; Singh, Harminder Pal; Pereira, Eduarda; Tuteja, Narendra


    Plants have to counteract unavoidable stress-caused anomalies such as oxidative stress to sustain their lives and serve heterotrophic organisms including humans. Among major enzymatic antioxidants, catalase (CAT; EC and ascorbate peroxidase (APX; EC are representative heme enzymes meant for metabolizing stress-provoked reactive oxygen species (ROS; such as H2O2) and controlling their potential impacts on cellular metabolism and functions. CAT mainly occurs in peroxisomes and catalyzes the dismutation reaction without requiring any reductant; whereas, APX has a higher affinity for H2O2 and utilizes ascorbate (AsA) as specific electron donor for the reduction of H2O2 into H2O in organelles including chloroplasts, cytosol, mitochondria, and peroxisomes. Literature is extensive on the glutathione-associated H2O2-metabolizing systems in plants. However, discussion is meager or scattered in the literature available on the biochemical and genomic characterization as well as techniques for the assays of CAT and APX and their modulation in plants under abiotic stresses. This paper aims (a) to introduce oxidative stress-causative factors and highlights their relationship with abiotic stresses in plants; (b) to overview structure, occurrence, and significance of CAT and APX in plants;

  19. Photoluminescence Probing of Complex H2O Adsorption on InGaN/GaN Nanowires.

    Maier, Konrad; Helwig, Andreas; Müller, Gerhard; Hille, Pascal; Teubert, Jörg; Eickhoff, Martin


    We demonstrate that the complex adsorption behavior of H2O on InGaN/GaN nanowire arrays is directly revealed by their ambient-dependent photoluminescence properties. Under low-humidity, ambient-temperature, and low-excitation-light conditions, H2O adsorbates cause a quenching of the photoluminescence. In contrast, for high humidity levels, elevated temperature, and high excitation intensity, H2O adsorbates act as efficient photoluminescence enhancers. We show that this behavior, which can only be detected due to the low operation temperature of the InGaN/GaN nanowires, can be explained on the basis of single H2O adsorbates forming surface recombination centers and multiple H2O adsorbates forming surface passivation layers. Reversible creation of such passivation layers is induced by the photoelectrochemical splitting of adsorbed water molecules and by the interaction of reactive H3O(+) and OH(-) ions with photoactivated InGaN surfaces. Due to electronic coupling of adsorbing molecules with photoactivated surfaces, InGaN/GaN nanowires act as sensitive nanooptical probes for the analysis of photoelectrochemical surface processes.

  20. Phase Separation Kinetics in Isopycnic Mixtures of H2O/CO2/Ethoxylated Alcohol Surfactants

    Lesemann, Markus; Paulaitis, Michael E.; Kaler, Eric W.


    Ternary mixtures of H2O and CO2 with ethoxylated alcohol (C(sub i)E(sub j)) surfactants form three coexisting liquid phases at conditions where two of the phases have equal densities (isopycnic phases). Isopycnic phase behavior has been observed for mixtures containing C8E5, C10E6, and C12E6 surfactants, but not for those mixtures containing either C4E1 or C8E3 surfactants. Pressure-temperature (PT) projections for this three-phase equilibrium were determined for H2O/CO2/C8E5 and H2O/CO2/C10E6 mixtures at temperatures from approximately 25 to 33 C and pressures between 90 and 350 bar. Measurements of the microstructure in H2O/CO2/C12E6 mixtures as a function of temperature (25-31 C), pressure (63.1-90.7 bar), and CO2 composition (0-3.9 wt%) have also been carried out to show that while micellar structure remains essentially un-changed, critical concentration fluctuations increase as the phase boundary and plait point are approached. In this report, we present our first measurements of the kinetics of isopycnic phase separation for ternary mixtures of H2O/CO2/C8E5.

  1. Multiple myeloma cells' capacity to decompose H2O2 determines lenalidomide sensitivity.

    Sebastian, Sinto; Zhu, Yuan X; Braggio, Esteban; Shi, Chang-Xin; Panchabhai, Sonali C; Van Wier, Scott A; Ahmann, Greg J; Chesi, Marta; Bergsagel, P Leif; Stewart, A Keith; Fonseca, Rafael


    Lenalidomide is an immunomodulatory drug (IMiDs) with clinical efficacy in multiple myeloma (MM) and other late B-cell neoplasms. Although cereblon (CRBN) is an essential requirement for IMiD action, the complete molecular and biochemical mechanisms responsible for lenalidomide-mediated sensitivity or resistance remain unknown. Here, we report that IMiDs work primarily via inhibition of peroxidase-mediated intracellular H2O2 decomposition in MM cells. MM cells with lower H2O2-decomposition capacity were more vulnerable to lenalidomide-induced H2O2 accumulation and associated cytotoxicity. CRBN-dependent degradation of IKZF1 and IKZF3 was a consequence of H2O2-mediated oxidative stress. Lenalidomide increased intracellular H2O2 levels by inhibiting thioredoxin reductase (TrxR) in cells expressing CRBN, causing accumulation of immunoglobulin light-chain dimers, significantly increasing endoplasmic reticulum stress and inducing cytotoxicity by activation of BH3-only protein Bim in MM. Other direct inhibitors of TrxR and thioredoxin (Trx) caused similar cytotoxicity, but in a CRBN-independent fashion. Our findings could help identify patients most likely to benefit from IMiDs and suggest direct TrxR or Trx inhibitors for MM therapy.

  2. First detection of 22 GHz H2O masers in TX Camelopardalis

    Cho, Se-Hyung; Yun, Youngjoo


    Simultaneous time monitoring observations of H$_{2}$O $6_{16}-5_{23}$, SiO $J$ = 1--0, 2--1, 3--2, and $^{29}$SiO $v$ = 0, $J$ = 1--0 lines were carried out in the direction of the Mira variable star TX Cam with the Korean VLBI Network single dish radio telescopes. For the first time, the H$_{2}$O maser emission from TX Cam was detected near the stellar velocity at five epochs from April 10, 2013 ($\\phi$ = 3.13) to June 4, 2014 ($\\phi$ = 3.89) including minimum optical phases. The intensities of H$_{2}$O masers are very weak compared to SiO masers. The variation of peak antenna temperature ratios among SiO $v$ = 1, $J$ = 1--0, $J$ = 2--1, and $J$ = 3--2 masers is investigated according to their phases. The shift of peak velocities of H$_{2}$O and SiO masers with respect to the stellar velocity is also investigated according to observed optical phases. The H$_{2}$O maser emission occurs around the stellar velocity during our monitoring interval. On the other hand, the peak velocities of SiO masers show a sprea...

  3. Degradation of 40 selected pharmaceuticals by UV/H2O2.

    Wols, B A; Hofman-Caris, C H M; Harmsen, D J H; Beerendonk, E F


    The occurrence of pharmaceuticals in source waters is increasing. Although UV advanced oxidation is known to be an effective barrier against micropollutants, degradation rates are only available for limited amounts of pharmaceuticals. Therefore, the degradation of a large group of pharmaceuticals has been studied in this research for the UV/H2O2 process under different conditions, including pharmaceuticals of which the degradation by UV/H2O2 was never reported before (e.g., metformin, paroxetine, pindolol, sotalol, venlafaxine, etc.). Monochromatic low pressure (LP) and polychromatic medium pressure (MP) lamps were used for three different water matrices. In order to have well defined hydraulic conditions, all experiments were conducted in a collimated beam apparatus. Degradation rates for the pharmaceuticals were determined. For those compounds used in this research that are also reported in literature, measured degradation results are in good agreement with literature data. Pharmaceutical degradation for only photolysis with LP lamps is small, which is increased by using a MP lamp. Most of the pharmaceuticals are well removed when applying both UV (either LP or MP) and H2O2. However, differences in degradation rates between pharmaceuticals can be large. For example, ketoprofen, prednisolone, pindolol are very well removed by UV/H2O2, whereas metformin, cyclophosphamide, ifosfamide are very little removed by UV/H2O2.

  4. Photodesorption of H2O, HDO, and D2O ice and its impact on fractionation

    Arasa, Carina; Kroes, Geert-Jan; Walsh, Catherine; van Dishoeck, Ewine F


    The HDO/H2O ratio in interstellar gas is often used to draw conclusions on the origin of water in star-forming regions and on Earth. In cold cores and in the outer regions of protoplanetary disks, gas-phase water comes from photodesorption of water ice. We present fitting formulae for implementation in astrochemical models using photodesorption efficiencies for all water ice isotopologues obtained using classical molecular dynamics simulations. We investigate if the gas-phase HDO/H2O ratio reflects that present in the ice or whether fractionation can occur during photodesorption. Probabilities for the top four monolayers are presented for photodesorption of X (X=H,D) atoms, OX radicals, and X2O and HDO molecules following photodissociation of H2O, D2O, and HDO in H2O amorphous ice at temperatures from 10-100 K. Isotope effects are found for all products: (1) H atom photodesorption probabilities from H2O ice are larger than those for D atom photodesorption from D2O ice by a factor of 1.1; the ratio of H and D ...

  5. Synthesis of CuO nanoflower and its application as a H2O2 sensor

    Aixia Gu; Guangfeng Wang; Xiaojun Zhang; Bin Fang


    CuO three-dimensional (3D) flower-like nanostructures were successfully synthesized by a simple method at 100°C with Cu(NO3)2.3H2O and NH3.H2O for 6 h in the absence of any additives. We found that NH3.H2O amount was critical for CuO morphology evolution. The phase analysis was carried out using X-ray diffraction (XRD) and the result confirmed that the CuO nanoflowers were single-phase. The morphological investigations by field emission scanning electron microscope (FESEM) revealed that the CuO nanoflowers were mono-dispersed in a large quantity and consisted of nanosheets. And then, CuO nanoflowers were successfully used to modify a gold electrode to detect H2O2 with cyclic voltammetry (CV) and amperometric (AC). It was found that CuO nanoflowers may be of great potential for H2O2 electrochemical sensing.

  6. Photodesorption of Ices II: H2O and D2O

    Oberg, Karin I; Visser, Ruud; van Dishoeck, Ewine F


    Gaseous H2O has been detected in several cold astrophysical environments, where the observed abundances cannot be explained by thermal desorption of H2O ice or by H2O gas phase formation. These observations hence suggest an efficient non-thermal ice desorption mechanism. Here, we present experimentally determined UV photodesorption yields of H2O and D2O ice and deduce their photodesorption mechanism. The ice photodesorption is studied under ultra high vacuum conditions and at astrochemically relevant temperatures (18-100 K) using a hydrogen discharge lamp (7-10.5 eV), which simulates the interstellar UV field. The ice desorption during irradiation is monitored using reflection absorption infrared spectroscopy of the ice and simultaneous mass spectrometry of the desorbed species. The photodesorption yield per incident photon is identical for H2O and D2O and depends on both ice thickness and temperature. For ices thicker than 8 monolayers the photodesorption yield Y is linearly dependent on temperature due to i...

  7. Rotationally Resolved Photoelectron Spectroscopic Study of the tilde{A}^+ State of H_2O^+

    Lauzin, Clément; Gans, Berenger; Jacovella, Ugo; Merkt, Frederic


    This talk will present the analysis of the rotationally resolved pulsed-field-ionization zero-kinetic-energy (PFI-ZEKE) photoelectron spectrum of H_2O and will be focussed on the tilde{A}^+←tilde{X} transitions. H_2O^+ in the tilde{A}^+ state is predicted to be linear. The sensitivity and the high resolution of PFI- ZEKE photoelectron spectroscopy allowed us to observe the rotational structure of low bending vibrational levels of the tilde{A}^+ state of H_2O^+ from the tilde{X} ground electronic state of H_2O. The assignment of the rotational structure of ionic levels previously observed by optical spectroscopy of the tilde{A}^+ - tilde{X}^+ band system of H_2O^+ will be presented and the intensity distribution of the photoelectron spectrum will be discussed in terms of the even or odd nature of the orbital angular momentum quantum number l of the photoelectron. Tentative assignments will be presented for several low-lying vibrational levels of the tilde{A}^+ state and compared with theoretical predictions ^c. They will also be discussed in terms of the rotational structure of higher tilde{A}^+ vibrational levels of the same symmetry. M. Brommer, B. Weis, B. Follmeg, P. Rosmus, S. Carter, N. C. Handy, H. J. Werner, and P. J. Knowles, J. Chem. Phys. 98, 5222 (1993) H. Lew, Can. J. Phys. 54, 2028 (1976).

  8. Synergistic effect of proanthocyanidin on the bactericidal action of the photolysis of H2O2.

    Ikai, Hiroyo; Nakamura, Keisuke; Kanno, Taro; Shirato, Midori; Meirelles, Luiz; Sasaki, Keiichi; Niwano, Yoshimi


    The in vitro antibacterial activity of the hydroxyl radical generation system by the photolysis of H2O2 in combination with proanthocyanidin, which refers to a group of polyphenolic compounds, was examined. Bactericidal activity of photo-irradiated H2O2 at 405 nm against Streptococcus mutans, a major pathogen of dental caries, was augmented in the presence of proanthocyanidin, whose bactericidal effect by itself was very poor, in a concentration-dependent manner. This combination was also proven effective against Porphyromonas gingivalis, a major pathogen of periodontitis. It is speculated that H2O2, generated from photo-irradiated proanthocyanidin around the bacterial cells, is photolyzed to the hydroxyl radical, which would in turn affect the membrane structure and function of the bacterial cells, resulting in augmented sensitivity of bacterial cells to the disinfection system utilizing the photolysis of H2O2. The present study suggests that the combination of H2O2 and proanthocyanidin works synergistically to kill bacteria when photo-irradiated.

  9. Optimal estimation of tropospheric H2O and δD with IASI/METOP

    F. Hase


    Full Text Available We present optimal estimates of tropospheric H2O and δD derived from radiances measured by the instrument IASI (Infrared Atmospheric Sounding Interferometer flown on EUMETSAT's polar orbiter METOP. We document that the IASI spectra allow for retrieving H2O profiles between the surface and the upper troposphere as well as middle tropospheric δD values. A theoretical error estimation suggests a precision for H2O of better than 35% in the lower troposphere and of better than 15% in the middle and upper troposphere, respectively, whereby surface emissivity and atmospheric temperature uncertainties are the leading error sources. For the middle tropospheric δD values we estimate a precision of 15–20‰ with the measurement noise being the dominating error source. The accuracy of the IASI products is estimated to about 20–10% and 10‰ for lower to upper tropospheric H2O and middle tropospheric δD, respectively. It is limited by systematic uncertainties in the applied spectroscopic parameters and the a priori atmospheric temperature profiles. We compare our IASI products to a large number of near coincident radiosonde in-situ and ground-based FTS (Fourier Transform Spectrometer remote sensing measurements. The bias and the scatter between the different H2O and δD data sets are consistent with the combined theoretical uncertainties of the involved measurement techniques.

  10. Competitive sorption of CO2 and H2O in 2:1 layer phyllosilicates

    Schaef, Herbert T.; Loring, John S.; Glezakou, Vassiliki-Alexandra; Miller, Quin R. S.; Chen, Jeffrey; Owen, Antoinette T.; Lee, Mal-Soon; Ilton, Eugene S.; Felmy, Andrew R.; McGrail, B. Pete; Thompson, Christopher J.


    Expandable clays such as montmorillonite have interlayer exchange sites whose hydration state can be systematically varied from near anhydrous to almost bulk-like water conditions. This phenomenon has new significance with the simultaneous implementation of geological sequestration and secondary utilization of CO2 to both mitigate climate warming and enhance extraction of methane from hydrated clay-rich formations. In this study, the partitioning of CO2 and H2O between Na-, Ca-, and Mg-exchanged montmorillonite and variably hydrated supercritical CO2 (scCO2) was investigated using in situ X-ray diffraction (HXRD), infrared (IR) spectroscopic titrations, and quartz crystal microbalance (QCM) measurements. Density functional theory calculations provided mechanistic insights. Structural volumetric changes were correlated to quantified changes in sorbed H2O and CO2 concentrations as a function of percent H2O saturation in scCO2. Intercalation of CO2 is inhibited when the clay is fully collapsed (dehydrated interlayer), peaks sharply with the introduction of some H2O and partial expansion of the interlayer region, and then decreases systematically with further hydration of the clay. This behavior is discussed in the context of recent theoretical calculations of the montmorillonite H2O-CO2 system.

  11. Excited OH+, H2O+, and H3O+ in NGC 4418 and Arp 220

    González-Alfonso, E; Bruderer, S; Müller, H S P; Graciá-Carpio, J; Sturm, E; Lutz, D; Poglitsch, A; Feuchtgruber, H; Veilleux, S; Contursi, A; Sternberg, A; Hailey-Dunsheath, S; Verma, A; Christopher, N; Davies, R; Genzel, R; Tacconi, L


    We report on Herschel/PACS observations of absorption lines of OH+, H2O+ and H3O+ in NGC 4418 and Arp 220. Excited lines of OH+ and H2O+ with E_lower of at least 285 and \\sim200 K, respectively, are detected in both sources, indicating radiative pumping and location in the high radiation density environment of the nuclear regions. Abundance ratios OH+/H2O+ of 1-2.5 are estimated in the nuclei of both sources. The inferred OH+ column and abundance relative to H nuclei are (0.5-1)x10^{16} cm-2 and \\sim2x10^{-8}, respectively. Additionally, in Arp 220, an extended low excitation component around the nuclear region is found to have OH+/H2O+\\sim5-10. H3O+ is detected in both sources with N(H3O+)\\sim(0.5-2)x10^{16} cm-2, and in Arp 220 the pure inversion, metastable lines indicate a high rotational temperature of ~500 K, indicative of formation pumping and/or hot gas. Simple chemical models favor an ionization sequence dominated by H+ - O+ - OH+ - H2O+ - H3O+, and we also argue that the H+ production is most likely...


    王寅观; 杨海涛; 孙庆德; 蒋勇; 钟斐晖


    In this paper,an on-line ultrasonic H2O2 concentration meteroperating according to the relationship between the concentration,temperature and ultrasonic velocity in H2O2 solution is introduced. The ultrasonic velocities in H2O2 solution are measured at different concentrations and temperatures.The velocity-concentration coefficients and velocity-temperature coefficients of H2O2 solution are calculated. In the on-line ultrasonic H2O2 concentration meter,the ultrasonic transducer installed outside the H2O2 solution pipeline generates an ultrasonic wave pulse. The ultrasonic wave travels through the pipeline of H2O2 solution. The computer transfers the ultrasonic travel time into ultrasonic velocity. The platinum resister is installed inside the H2O2 solution pipeline. The resistor variation caused by temperature is sent to the computer through the interface. The computer calculates the ultrasonic velocity and H2O2 temperature by means of velocity-concentration coefficients and velocity-temperature coefficients. It displays and prints the value of the instant H2O2 solution concentration,and meantime displays the 8 hour curve for H2O2 solution concentration variation in the screen. It also can give alarm and output a 4—20 mA analogue signal for automatic control in the production process.

  13. A family of new glutarate compounds: synthesis, crystal structures of: Co(H2O)5L(1), Na2[CoL2] (2), Na2[L(H2L)4/2] (3), {[Co3(H2O)6L2](HL)2}.4H2O (4), {[Co3(H2O)6L2](HL)2}.10H2O (5), {[Co3(H2O)6L2]L2/2}.4H2O (6), and Na2{[Co3(H2O)2]L8/2].6H2O (7), and magnetic properties of 1 and 2 with H2L = HOOC-(CH2)3-COOH.

    Zheng, Yue-Qing; Lin, Jian-Li; Xu, Wei; Xie, Hong-Zhen; Sun, Jie; Wang, Xian-Wen


    Seven new glutaric acid complexes, Co(H 2O) 5L 1, Na 2[CoL 2] 2, Na 2[L(H 2L) 4/2] 3, {[Co 3(H 2O) 6L 2](HL) 2}.4H 2O 4, {[Co 3(H 2O) 6L 2](HL) 2}.10H 2O 5, {[Co 3(H 2O) 6L 2]L 2/2}.4H 2O 6, and Na 2{[Co 3(H 2O) 2]L 8/2].6H 2O 7 were obtained and characterized by single-crystal X-ray diffraction methods along with elemental analyses, IR spectroscopic and magnetic measurements (for 1 and 2). The [Co(H 2O) 5L] complex molecules in 1 are assembled into a three-dimensional supramolecular architecture based on intermolecular hydrogen bonds. Compound 2 consists of the Na (+) cations and the necklace-like glutarato doubly bridged [ C o L 4 / 2 ] 2 - infinity 1 anionic chains, and 3 is composed of the Na (+) cations and the anionic hydrogen bonded ladder-like [ L ( H 2 L ) 4 / 2 ] 2 - infinity 1 anionic chains. The trinuclear {[Co 3(H 2O) 6L 2](HL) 2} complex molecules with edge-shared linear trioctahedral [Co 3(H 2O) 6L 2] (2+) cluster cores in 4 and 5 are hydrogen bonded into two-dimensional (2D) networks. The edge-shared linear trioctahedral [Co 3(H 2O) 6L 2] (2+) cluster cores in 6 are bridged by glutarato ligands to generate one-dimensional (1D) chains, which are then assembled via interchain hydrogen bonds into 2D supramolecular networks. The corner-shared linear [Co 3O 16] trioctahedra in 7 are quaternate bridged by glutarato ligands to form 1D band-like anionic {[Co 3(H 2O) 2]L 8/2} (2+) chains, which are assembled via interchain hydrogen bonds into 2D layers, and between them are sandwiched the Na (+) cations. The magnetic behaviors of 1 and 2 obey the Curie-Weiss law with chi m = C/( T - Theta) with the Curie constant C = 3.012(8) cm (3) x mol (-1) x K and the Weiss constant Theta = -9.4(7) K for 1, as well as C = 2.40(1) cm (3) x mol (-1) x K and Theta = -2.10(5) K for 2, indicating weak antiferromagnetic interactions between the Co(II) ions.

  14. Water Exchange on [Ln(DO3A)(H2O)2] and [Ln(DTTA-Me)(H2O)2](-) Studied by Variable Temperature, Pressure, and Magnetic Field NMR.

    Karimi, Shima; Helm, Lothar


    Water exchange kinetics of [Ln(L)(H2O)2](x) complexes (Ln = Pr, Nd, Dy, Tm, and Yb; L = DO3A and DTTA-Me) were studied by (17)O NMR spectroscopy as a function of temperature, pressure, and frequency and by (1)H nuclear magnetic relaxation dispersion. Water exchange rate constants of both complexes show a maximum at dysprosium. Water exchange on negatively charged complexes of the acyclic DTTA-Me ligand is much faster than on the neutral complexes of the macrocyclic DO3A. Small activation volumes |ΔV(⧧)| studied. In the case of [Ln(DTTA-Me)(H2O)2](-), a change in mechanism is detected from a dissociative mechanism (D, ΔV(⧧) = 7 cm(3) mol(-1)) for complexes with larger ions (Pr to Gd) to an interchange mechanism (Id, I; ΔV(⧧) = +1.8 and +0.4 cm(3) mol(-1)) for complexes with smaller ions (Dy and Tm).

  15. Investigating the adsorption of H2O on ZnO nanoclusters by first principle calculations

    Al-Sunaidi, Abdullah A.


    The interaction of a single H2O molecule on selected ZnO nanoclusters is investigated by carrying out calculations based on the density-functional theory at the hybrid-GGA (B97-2) level. These clusters have ring, drum, tube and bubble shapes and their physical properties like the binding energy and the band gap energy depend strongly on the shape and size of the cluster. Depending on the stability of the cluster, H2O show both chemisorption and dissociation on the surfaces of the clusters. We analyzed the effect of H2O adsorption on the properties of clusters of size n = 12 via the density of state, HOMO-LUMO orbitals and the changes in the IR frequencies. © 2011 Elsevier B.V. All rights reserved.

  16. Simulations of H 2O 2 concentration profiles in the water surrounding spent nuclear fuel

    Nielsen, Fredrik; Lundahl, Karin; Jonsson, Mats


    A simple mathematical model describing the hydrogen peroxide concentration profile in water surrounding a spent nuclear fuel pellet as a function of time has been developed. The water volume is divided into smaller elements, and the processes that affect hydrogen peroxide concentration are applied to each volume element. The model includes production of H 2O 2 from α-radiolysis, surface reaction between H 2O 2 and UO 2 and diffusion. Simulations show that the surface concentration of H 2O 2 increases fairly rapidly and approaches the steady-state concentration. The time to reach steady-state is sufficiently short to be neglected compared to the times of interest when simulating spent fuel dissolution under deep repository conditions. Consequently, the steady-state approach can be used to estimate the rate for radiation-induced spent nuclear fuel dissolution.

  17. Sustainable hydrocarbon fuels by recycling CO2 and H2O with renewable or nuclear energy

    Graves, Christopher R.; Ebbesen, Sune; Mogensen, Mogens Bjerg


    . The dominant costs of the process are the electricity cost and the capital cost of the electrolyzer, and this capital cost is significantly increased when operating intermittently (on renewable power sources such as solar and wind). The potential of this CO2 recycling process is assessed, in terms of what......) and biofuels have received the most attention, similar hydrocarbons can be produced without using fossil fuels or biomass. Using renewable and/or nuclear energy, carbon dioxide and water can be recycled into liquid hydrocarbon fuels in non-biological processes which remove oxygen from CO2 and H2O (the reverse...... dissociation, and fuel synthesis. Dissociation methods include thermolysis, thermochemical cycles, electrolysis, and photoelectrolysis of CO2 and/or H2O. High temperature co-electrolysis of H2O and CO2 makes very efficient use of electricity and heat (near-100% electricity-to-syngas efficiency), provides high...

  18. Rheological Properties of Cubic Liquid Crystals Formed from Monoglyceride/H2O Systems

    水玲玲; 王志宁; 郑利强


    Monoglyceride (MO) can form various liquid crystalline phases spontaneously in the presence of various amount of water at room temperature. The appropriate compositions from binary phase diagram of MO/H2O were selected to form cubic phases. The selected systems were studied at different salt concentrations and pH value using rheological methods. There was a weak effect of salt on viscoelastic properties of cubic phases formed from MO/H2O system. Hexagonal phase was formed when pH value was decreased or increased. The viscoelasticity of cubic phases was different from that of hexagonal liquid crystals. Rheological properties of MO/H2O cubic phases were stable at pH and salt concentration similar to physiological condition.

  19. A Survey and Statistics of Interstellar OH and H2O Masers

    Han-Ping Liu; J. R. Forster; Jin Sun


    We present a statistical analysis of a sky survey of interstellar H2O and OH masers. These masers can be classified into three categories: isolated H2O masers, isolated OH masers, and simple OH/H2O maser associations. The total number of sources in each category is of the same order of magnitude, and as an evolutionary phase they can maintain ~ 105 yr. An improved radiative pumping mechanism is proposed. This model avoids some of the deficiencies of previous radiative models, such as shortage of exciting photons. The statistical results obtained from the survey can be interpreted by the new mechanism together with the evolutionary model in which the gravitational force of the central stellar objects is responsible for the HII region.

  20. Hydrogen bonding and π-π stacking in nicotinamide/H2O mixtures

    Zhai, Cuiping; Zhang, Ping; Peng, Peng; Hou, Bingbing; Li, Lina


    The interactions between nicotinamide (NA) and H2O were studied using UV-visible spectra (UV-Vis), cyclic voltammetry (CV), nuclear magnetic resonance (NMR), density functional theory (DFT) and atoms in molecules (AIM) analysis. According to the changes of the UV-Vis spectra and the oxidation and reduction potentials in cyclic voltammograms of NA in aqueous solution, it was found that hydrogen bonding occurred between NA and H2O molecules. Quantum chemistry calculations and AIM analysis further confirmed the existence of hydrogen bonding between H2O molecules and the amide group, the nitrogen atom, and hydrogen atoms on the pyridine ring of NA molecules. In addition, the NMR results demonstrated that the π-π stacking between NA pyridine rings could be formed at higher concentrations.

  1. Modification and secondary packaging of Na2SO4·10H2O

    XIAO, Liguang; ZHAO, Mingyue


    Na2SO4·10H2O, commonly known as mirabilite, phase change temperature is 32°C, enthalpy is 254 J/g, with large surpercooling degree and easy to stratify. This paper improved the properties of Na2SO4·10H2O by Na2HPO4·12H2O and CMC, expanded glass beads, silica fume, grinded diatomaceous earth, straw powder was used to parcle and covered it twice respectively. Grinded diatomaceous earth showed best effect, with phase change temperature 22-30°C, enthalpy was 168J/g average, and there was no leakage when the temperature went to 40°C.

  2. Theoretical study of the rovibrational spectrum of H2O-H2

    Wang, Xiao-Gang; Carrington, Tucker


    In this paper we report transition frequencies and line strengths computed for H_2O-H_2 and compare with the experimental observations of [M. J. Weida and D. J. Nesbitt, J. Chem. Phys. 110, 156 (1999)]. To compute the spectra we use a symmetry adapted Lanczos algorithm and an uncoupled product basis set. Our results corroborate the assignments of Weida and Nesbitt and there is good agreement between calculated and observed transitions. Possible candidates for lines that Weida and Nesbitt were not able to assign are presented. Several other bands that may be observable are also discovered. Although all the observed bands are associated with states localized near the global potential minimum, at which H_2O acts as proton acceptor, a state with significant amplitude near the T-shape secondary potential minimum at which H_2O acts as proton donor is identified by examining many different probability density plots.

  3. Diels-Alder addition to H2O@C60 an electronic and structural study

    Reveles, J. Ulises; Govinda, K. C.; Baruah, Tunna; Zope, Rajendra R.


    Exohedral reactivity of endohedral fullerenes has aroused a significant interest because of its potential applications. The present letter examines the effect of an entrapped single water molecule on the reactivity of C60. We study the thermodynamics and kinetics of a Diels-Alder reaction occurring at all non-identical bonds of free C60 and H2O@C60. Our calculations show that encapsulation of water does not have a significant effect on H2O@C60 reactivity compared to C60, as attested by the investigation of the reaction under several orientations of H2O inside C60. Reaction and activation energies indicate that [6,6] bonds are the most reactive sites.

  4. Variability of H2O and SO2 on Venus between 2012 and 2016

    Encrenaz, Therese A.; Greathouse, Thomas K.; Richter, Matthew; DeWitt, Curtis; Widemann, Thomas; Bézard, Bruno; Fouchet, Thierry; Atreya, Sushil K.; Sagawa, Hideo


    Since January 2012, we have been using the TEXES high-resolution imaging spectrometer at the NASA Infrared Telescope Facility to map sulfur dioxide and deuterated water over the disk of Venus. Data have been recorded in two spectral ranges around 1348 cm-1 (7.4 microns) and 530 cm-1 (19 microns), in order to probe the cloudtop at an altitude of about 64 km (SO2 and HDO at 7 microns) and a few kilometers below (SO2 at 19 microns). Observations took place during six runs between January 2012 and January 2016. The diameter of Venus ranged between 12 and 33 arcsec. Data were recorded with a spectral resolving power as high as 80000 and a spatial resolution of about 1 arcsec (at 7 microns) and 2.5 arcsec (at 19 microns). Mixing ratios have been estimated from HDO/CO2 and SO2/CO2 line depth ratios, using weak neighboring transitions of comparable depths. All data show that the two molecules have a very different behavior. The HDO maps are globally uniform over the disk. The variations of the disk-integrated H2O mixing ratio (estimated assuming a D/H of 200 VSMOW in the mesosphere of Venus) varies by about a factor 1.5 over the four-year period. A constant value of 1.0 - 1.5 pppmv is obtained in most of the cases. The SO2 maps, in contrast, show strong variations over the disk of Venus, by a factor as high as 5. Long-term variations of SO2 show that the disk-integrated SO2 mixing ratio varies between 2012 and 2016 by a factor as high as 10, with a minimum value of 30 +/- 5 ppbv in February 2014 an a maximum value of 300 +/- 50 ppbv in January 2016. The SO2 maps also show a strong short-term variability, with a timescale of a few hours.

  5. Sailuotong Prevents Hydrogen Peroxide (H2O2)-Induced Injury in EA.hy926 Cells

    Seto, Sai Wang; Chang, Dennis; Ko, Wai Man; Zhou, Xian; Kiat, Hosen; Bensoussan, Alan; Lee, Simon M. Y.; Hoi, Maggie P. M.; Steiner, Genevieve Z.; Liu, Jianxun


    Sailuotong (SLT) is a standardised three-herb formulation consisting of Panax ginseng, Ginkgo biloba, and Crocus sativus designed for the management of vascular dementia. While the latest clinical trials have demonstrated beneficial effects of SLT in vascular dementia, the underlying cellular mechanisms have not been fully explored. The aim of this study was to assess the ability and mechanisms of SLT to act against hydrogen peroxide (H2O2)-induced oxidative damage in cultured human vascular endothelial cells (EAhy926). SLT (1–50 µg/mL) significantly suppressed the H2O2-induced cell death and abolished the H2O2-induced reactive oxygen species (ROS) generation in a concentration-dependent manner. Similarly, H2O2 (0.5 mM; 24 h) caused a ~2-fold increase in lactate dehydrogenase (LDH) release from the EA.hy926 cells which were significantly suppressed by SLT (1–50 µg/mL) in a concentration-dependent manner. Incubation of SLT (50 µg/mL) increased superoxide dismutase (SOD) activity and suppressed the H2O2-enhanced Bax/Bcl-2 ratio and cleaved caspase-3 expression. In conclusion, our results suggest that SLT protects EA.hy916 cells against H2O2-mediated injury via direct reduction of intracellular ROS generation and an increase in SOD activity. These protective effects are closely associated with the inhibition of the apoptotic death cascade via the suppression of caspase-3 activation and reduction of Bax/Bcl-2 ratio, thereby indicating a potential mechanism of action for the clinical effects observed. PMID:28067784

  6. Syntheses and Crystal Structures of Two Cyano-bridged Bimetallic Complexes [Ce(DMSO)4(H2O)3Fe(CN)6]·H2O and [La(DMSO)4(H2O)3Co(CN)6]·H2O (DMSO = Dimethylsulfoxide)

    ZHAO Zhen-Qian; CHEN Wen-Tong; LIU Xi; CAI Li-Zhen; GUO Guo-Cong; HUANG Jin-Shun


    Two new bimetallic cyano-bridged complexes [Ce(DMSO)4(H2O)3Fe(CN)6]·H2O 1 and [La(DMSO)4(H2O)3Co(CN)6]·H2O 2 have been prepared by the ball milling reaction method and structurally characterized by X-ray single-crystal structure analyses. Crystallographic data for 1:C14H32CeFeN6O8S4, Mr = 736.67, monoclinic, space group P21/n, a = 14.952(1), b =13.7276(9), c = 15.392(1) (A), β = 108.288(1)°, V = 2999.6(4) (A)3, Z = 4, Dc= 1.631 g/cm3,μ =2.304 mm-1, F(000) = 1480, R = 0.0593 and wR = 0.1611; and those for 2: C14H32CoLaN6O8S4,Mr=738.54, monoclinic, space group P21/n, a = 14.945(3), b = 13.731(3), c = 15.300(3) (A), β=107.806(1)°, V= 2989.3(11) (A)3, Z = 4, Dc = 1.641 g/cm3,μ = 2.288 mm-1, F(000) = 1480, R =0.0383 and wR = 0.1132. In both complexes the lanthanide ion is eight-coordinated in a square antiprism arrangement, and the Fe(Ⅲ) or Co(Ⅲ) ion in a nearly regular octahedral environment.The [LnM(CN)6(DMSO)4(H2O)3]·H2O (Ln = Ce and M = Fe for 1; Ln = La and M = Co for 2)species are held together via hydrogen bonds by coordinated water molecules, lattice water molecules and nitrogen atoms of cyanide groups to form a three-dimensional framework.

  7. Sailuotong Prevents Hydrogen Peroxide (H2O2-Induced Injury in EA.hy926 Cells

    Sai Wang Seto


    Full Text Available Sailuotong (SLT is a standardised three-herb formulation consisting of Panax ginseng, Ginkgo biloba, and Crocus sativus designed for the management of vascular dementia. While the latest clinical trials have demonstrated beneficial effects of SLT in vascular dementia, the underlying cellular mechanisms have not been fully explored. The aim of this study was to assess the ability and mechanisms of SLT to act against hydrogen peroxide (H2O2-induced oxidative damage in cultured human vascular endothelial cells (EAhy926. SLT (1–50 µg/mL significantly suppressed the H2O2-induced cell death and abolished the H2O2-induced reactive oxygen species (ROS generation in a concentration-dependent manner. Similarly, H2O2 (0.5 mM; 24 h caused a ~2-fold increase in lactate dehydrogenase (LDH release from the EA.hy926 cells which were significantly suppressed by SLT (1–50 µg/mL in a concentration-dependent manner. Incubation of SLT (50 µg/mL increased superoxide dismutase (SOD activity and suppressed the H2O2-enhanced Bax/Bcl-2 ratio and cleaved caspase-3 expression. In conclusion, our results suggest that SLT protects EA.hy916 cells against H2O2-mediated injury via direct reduction of intracellular ROS generation and an increase in SOD activity. These protective effects are closely associated with the inhibition of the apoptotic death cascade via the suppression of caspase-3 activation and reduction of Bax/Bcl-2 ratio, thereby indicating a potential mechanism of action for the clinical effects observed.

  8. Sipunculan celomocytes increase the resistance to H2O2-induced cell death under hypoxia

    T Lombardo


    Full Text Available Themiste petricola is a marine intertidal endolithic worm that experiences transient hypoxia within its habitat, owing to natural sediment movements or increased organic enrichment. We characterized and quantified the cytotoxic effect of H2O2 in celomocytes of the sipunculan Themiste petricola under normoxia and hypoxia (O2 < 0.1 % through the median effect method. The 50 % cell death H2O2 dose at 24 h (EC50 under normoxia was 1.5 mM. The range EC10-EC90 was 0.6 mM - 3.9 mM. The fraction of cells having collapsed mitochondrial membrane potential (MMP was increased dose-dependently after 3 h exposure with 24 h cytotoxic doses of H2O2 from EC10 to EC90. The 24 h cytotoxic dose inducing 50 % of cells with collapsed MMP at 3 h was 3.67 mM. Intracellular superoxide anion production was increased dose-dependently, while reduced glutathione was decreased dose-dependently at 3 h with H2O2 from EC10 to EC90. Exposure to 24 h hypoxia did not cause cell death but induced intracellular acidification. The 24 h EC50 of H2O2 under hypoxia was increased to 4.7 mM while the range EC10-EC90 was increased to 0.9 mM - 25.1 mM. We conclude that hypoxia induces anaerobic metabolism and increases tolerance to H2O2-induced cell death in celomocytes of Themiste petricola preserving the immune functions and providing an advantage to survive under low oxygen tension.

  9. H2O2 Improves Quality of Radix scutellariae Through Anti-oxidant Effect.

    Qi, Song; Wu-Lin, Cao; Hua, Jiang; Ai-Hua, Zhang; Xiang-Cai, Meng


    The correlation between the quality and geographical origin of herbal medicine was traced back to Tang Dynasty in China, more than 1200 years, and the effects of ecological environments on the secondary metabolites such as flavonoids have been confirmed. However, little is known about how the adversity impacts on the quality. Reactive oxygen species (ROS) may be medium between the ecological environment and the secondary metabolism. The fresh roots of Scutellaria baicalensis Georgi were treated with 0.002 μmol/L, 0.2 μmol/L, and 20 μmol/L H2O2, respectively. A stress model was established to elucidate the change of secondary metabolism, anti-oxidant enzyme system, and enzymes relating to flavonoids. The activities of superoxide dismutase, catalase and peroxidase decreased. Too much H2O2, firstly, boosted transformation of flavonoids glycoside into aglucon with the most remarkable activities through UDP-glucuronate baicalein 7-O-glucuronosyltransferase (UBGAT), and β-glucuronidase (GUS), then regulated the gene expression of phenylalanine ammonialyase, GUS, and UBGAT, and increased the contents of flavones, motivated the flavonoid glycoside converting into aglucon. With this action, the flavones displaced the anti-oxidant enzymes. The higher the dosage, the more baicalein and wogonin increased, the later they took action. The plant secondary metabolites to keep ROS constant are identical to the effective materials in clinic. They are closely linked. H2O2 can improve flavones, especially the aglucon, and further increased the quality of herbal medicine, which possesses very important value in medical practice. H2O2 decreasing the activities of CAT and POD lead to accumulation of more H2O2. Excess of H2O2 up-regulated PAL, BUG, promote biosynthesis of flavones, and enhance the nonenzyme system. "↑" and "↓" represent activity or content "up" and "down" respectively.

  10. [Study on UV and H2O2 combined inactivation of E. coli in drinking water].

    Zhang, Yi-Qing; Zhou, Ling-Ling; Zhang, Yong-Ji


    The inactivation effect of E. coli with both UV irradiation and hydrogen peroxide disinfection individually and in different combination modes was investigated. The results showed that hydrogen peroxide alone caused hardly any inactivation of E. coli. Only 0.02 lg inactivation was achieved by hydrogen peroxide with concentration of 20 mg x L(-1) and contact time of 30 min. UV irradiation was able to inactivate E. coli to a certain extent. The inactivation reached 4.51 lg at a UV dose of 10 mJ x cm(-2). The combination of UV and H2O2 could significantly improve the inactivation effect and the different combination modes affected the inactivation effect. The inactivation effect of UV-H2O2 was better than that of H2O2 -UV. The inactivation was increased by 0.09, 0.35, 0.38, 0.68 lg and 0.01, 0.07, 0.14, 0.53 lg when compared to the treatment with solely UV irradiation, respectively, at UV dose of 5 mJ x cm(-2) with hydrogen peroxide at contact time of 2.5, 5, 10, 20 minutes. UV/H2O2 achieved better results than sequential disinfection. The inactivation was enhanced by 0.43 lg and 0.58 lg when compared to UV-H2O2 and H2O2-UV, respectively, at UV dose of 5 mJ x cm(-2) with hydrogen peroxide at contact time of 20 minutes. The inactivation of E. coli increased with the enhancement of UV radiation intensity.

  11. Competitive Sorption of CO2 and H2O in 2:1 Layer Phyllosilicates

    Schaef, Herbert T.; Loring, John S.; Glezakou, Vassiliki Alexandra; Miller, Quin R.; Chen, Jeffrey; Owen, Antionette T.; Lee, Mal Soon; Ilton, Eugene S.; Felmy, Andrew R.; McGrail, B. Peter; Thompson, Christopher J.


    The salting out effect, where increasing the ionic strength of aqueous solutions decreases the solubility of dissolved gases is a well-known phenomenon. Less explored is the opposite process where an initially anhydrous system containing a volatile, relatively non-polar component and inorganic ions is systematically hydrated. Expandable clays such as montmorillonite are ideal systems for exploring this scenario as they have readily accessible exchange sites containing cations that can be systematically dehydrated or hydrated, from near anhydrous to almost bulk-like water conditions. This phenomenon has new significance with the simultaneous implementation of geological sequestration and secondary utilization of CO2 to both mitigate climate warming and enhance extraction of methane from hydrated clay-rich formations. Here, the partitioning of CO2 and H2O between Na-, Ca-, and Mg-exchanged montmorillonite and variably hydrated supercritical CO2 (scCO2) was investigated using in situ X-ray diffraction, infrared (IR)spectroscopic titrations, and quartz crystal microbalance (QCM) measurements. Density functional theory calculations provided mechanistic insights. Structural volumetric changes were correlated to quantified changes in sorbed H2O and CO2 concentrations as a function of %H2O saturated in scCO2. Intercalation of CO2 is favored at low H2O/CO2 ratios in the interlayer region, where CO2 can solvate the interlayer cation. As the clay becomes more hydrated and the H2O/CO2 ratio increases, H2O displaces CO2 from the solvation shell of the cation and CO2 tends to segregate. This transition decreases both the entropic and enthalpic driving force for CO2 intercalation, consistent with experimentally observed loss of intercalated CO2.

  12. Formation of glycine from HCN and H2O: A computational mechanistic study

    Lee, Hyun Moo; Choe, Joong Chul


    The potential energy surfaces for the formation of glycine from HCN and H2O were determined from CBS-QB3 calculations. After the formation of a HCN trimer, amino malononitrile, amino malononitrile monoamide (3) was formed by a water addition reaction. Two pathways were found for the subsequent reaction, 3 + 2H2O → glycine + HNCO + NH3. One pathway involving an amino ketone was much more favored than the other pathway involving glycinamide. Addition of a water molecule as a catalyst greatly enhanced steps occurring by hydrogen rearrangement.

  13. Kinetics of oxidation of odorous sulfur compounds in aqueous alkaline solution with H2O2.

    Feliers, C; Patria, L; Morvan, J; Laplanche, A


    Sulfur species oxidation is a crucial issue wastewater treatment. The production of sulfur compounds like H2S,CH3SH, C2H5SH, disulfides and dimethyle sulfide generates odorous nuisances for the neighborhood. The oxidation of these species by H2O2 in alkaline solution has been investigated. The results showed that thiols CH3SH and C2H5SH react with H202 only in their dissociated form RS- with rate constants respectively k = 8.81 +/- 0.48 M-1s-1 and 8.37 +/- 0.63 M-1.s-1. Mercaptans oxidation produces 100 % of dimethyldisulfide or diethyldisulfide. The oxidation of disulfides shows a difference of reactivity between H2O2 and HO2- towards sulfur species. Increasing the pH accelerates significantly the reactions in the case of CH3SSCH3. The oxidation rate can be described as: r = k[RSSR][H2O2][RSSR][H2O2] + k[RSSR][HO2-] [RSSR][HO2-] with k[RSSR][H2O2] = 1.2 x 10(-4) +/- 0.2 x 10(-4) M-1s-1 and k[RSSR][HO2-] = 3.4 x 10(-4) +/- 0.6 x 10(-4) M-1.s-1 for CH3SSCH3. Dimethyl sulfide presents a reactivity different from disulfides. The oxidation rate can also be described as: r = k[CH3SCH3][H2O21][CH3SCH3][H2O2] + k[CH3SCH3][HO-] [CH3SCH3][HO2-], however, oxidation rate decreases with pH increase. k[CH3SCH3][H2O2] = 12.8 x 10(-3) +/- 0.96 x 10(-3) M-1.s-1 and k[CH3SCH3][HO2-] = 4 x 10(-3) +/- 0.3 x 10(-3) M-1.s-1.

  14. Diatomite as high performance and environmental friendly catalysts for phenol hydroxylation with H2O2

    Yuxin Jia et al


    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.

  15. Using HDO/H2O dynamics to constrain GCM convective processes during the MJO

    Tuinenburg, Obbe; Risi, Camille; Lacour, Jean-Lionel; Schneider, Matthias


    This research aims to improve the convective processes during the MJO and other modes of intra-seasonal variability in the LMDZ atmospheric models, by making use of joint HDO and H2O (vapor) measurements. The joint use of HDO/H2O yields additional information compared to sole humidity measurements. In addition to atmospheric drying and wetting derived from the humidity measurements, the HDO measurements provide enrichment and depletion information. This information is used to distinguish between different moistening and drying processes. For example, a separation can be made between atmospheric moistening due to ocean surface evaporation and due to rain re-evaporation, as the re-evaporating moisture is more depleted in HDO than the surface evaporation. We use IASI and TES satellite HDO and H2O measurements and determine their evolution in the troposphere (700 to 400 hPa) during the MJO. Moreover, these evolutions are compared to the isotope enabled LMDZ GCM, which is forced with reanalysis wind fields. In this nudged mode, sensitivity tests of key parameters (cold pool representation, entrainment rate, precipitation efficiency, droplet size and fall speed, etc.) in the convection scheme are performed and compared with the measurements. Initial results suggest that over the Indian ocean, there is a difference between the lower- and mid-tropospheric HDO-H2O dynamics for MJO events. In the lower troposphere (at 700 hPa), the dynamics of HDO and H2O are exactly out of phase, following a curve which indicates surface moistening by surface evaporation throughout the MJO event. At 500 hPa, the measurements indicate the main moisture source is surface evaporation before the MJO peak and rain re-evaporation during the 10 days after the MJO peak. Over the maritime continent, the dynamics are the same in the lower and mid-troposphere. The predominant source is surface evaporation before the event, and re-evaporation during the 10 days after the event. The model captures the

  16. Ammonia removal from leachate by photochemical process using H2O2

    Giovani Archanjo Brota


    Full Text Available In this work, it was studied the optimization of the photochemical process using H2O2/UV in order to reduce the concentration of ammonia in leachate. It was used landfills leachate previously treated in the development of studies. A photochemical reactor with the capacity of 1.7 liters equipped with refrigeration system and recirculation of leachate was employed in the research. The influence of temperature, the light bulb power, the concentration of H2O2 and treatment time were tested during the study. A removal of 97% of ammonia was observed at 90 min.

  17. One- or Two-Electron Water Oxidation, Hydroxyl Radical, or H2O2 Evolution.

    Siahrostami, Samira; Li, Guo-Ling; Viswanathan, Venkatasubramanian; Nørskov, Jens K


    Electrochemical or photoelectrochemcial oxidation of water to form hydrogen peroxide (H2O2) 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 O2 evolution. We develop a thermochemical picture of the catalyst properties that determine selectivity toward the one, two, and four electron processes leading to (•)OH, H2O2, and O2.

  18. System and method to control h2o2 level in advanced oxidation processes


    The present invention relates to a bio-electrochemical system (BES) and a method of in-situ production and removal of H2O2 using such a bio-electrochemical system (BES). Further, the invention relates to a method for in-situ control of H2O2 content in an aqueous system of advanced oxidation...... processes (AOPs) involving in-situ generation of hydroxyl radical (OH) by using such a bio-electrochemical system (BES) and to a method for treatment of wastewater and water disinfection. The bio-electrochemical system (BES) according to the invention comprises: - an aqueous cathode compartment comprising...

  19. Effect of plant extracts on H2O2-induced inflammatory gene expression in macrophages

    Pomari, Elena; Stefanon, Bruno; Colitti, Monica


    Background Arctium lappa (AL), Camellia sinensis (CS), Echinacea angustifolia, Eleutherococcus senticosus, Panax ginseng (PG), and Vaccinium myrtillus (VM) are plants traditionally used in many herbal formulations for the treatment of various conditions. Although they are well known and already studied for their anti-inflammatory properties, their effects on H2O2-stimulated macrophages are a novel area of study. Materials and methods Cell viability was tested after treatment with increasing doses of H2O2 and/or plant extracts at different times of incubation to identify the optimal experimental conditions. The messenger (m)RNA expression of TNFα, COX2, IL1β, NFκB1, NFκB2, NOS2, NFE2L2, and PPARγ was analyzed in macrophages under H2O2 stimulation. The same genes were also quantified after plant extract treatment on cells pre-stimulated with H2O2. Results A noncytotoxic dose (200 μM) of H2O2 induced active mRNA expression of COX2, IL1β, NFE2L2, NFκB1, NFκB2, NOS2, and TNFα, while PPARγ was depressed. The expression of all genes tested was significantly (P<0.001) regulated by plant extracts after pre-stimulation with H2O2. COX2 was downregulated by AL, PG, and VM. All extracts depressed IL1β expression, but upregulated NFE2L2. NFκB1, NFκB2, and TNFα were downregulated by AL, CS, PG, and VM. NOS2 was inhibited by CS, PG, and VM. PPARγ was decreased only after treatment with E. angustifolia and E. senticosus. Conclusion The results of the present study indicate that the stimulation of H2O2 on RAW267.4 cells induced the transcription of proinflammatory mediators, showing that this could be an applicable system by which to activate macrophages. Plant extracts from AL, CS, PG, and VM possess in vitro anti-inflammatory activity on H2O2-stimulated macrophages by modulating key inflammation mediators. Further in vitro and in vivo investigation into molecular mechanisms modulated by herbal extracts should be undertaken to shed light on the development of novel

  20. Theoretical Study of Electron Transfer in Bimolecular System of NH3 and H2O


    Mulliken, NPA, MK and CHelpG population analyses have been accomplished at the level of MP2/6-31G(d,p) for the title system. The variations of four kinds of charges on NH3 with intermolecular distance infer that electron transfers from NH3 to H2O. MK and CHelpG population analyses indicate more electron transfer than Mulliken and NPA ones. The atomic charges resulted from MK and CHelpG schemes infer that electron transfers from N in NH3 to H in H2O, which confirms that this bimolecular complex possesses linear structure as H3N…HOH.

  1. Effect of plant extracts on H2O2-induced inflammatory gene expression in macrophages

    Pomari E


    Full Text Available Elena Pomari, Bruno Stefanon, Monica Colitti Department of Agricultural and Environmental Sciences, University of Udine, Udine, Italy Background: Arctium lappa (AL, Camellia sinensis (CS, Echinacea angustifolia, Eleutherococcus senticosus, Panax ginseng (PG, and Vaccinium myrtillus (VM are plants traditionally used in many herbal formulations for the treatment of various conditions. Although they are well known and already studied for their anti-inflammatory properties, their effects on H2O2-stimulated macrophages are a novel area of study. Materials and methods: Cell viability was tested after treatment with increasing doses of H2O2 and/or plant extracts at different times of incubation to identify the optimal experimental conditions. The messenger (mRNA expression of TNFα, COX2, IL1β, NFκB1, NFκB2, NOS2, NFE2L2, and PPARγ was analyzed in macrophages under H2O2 stimulation. The same genes were also quantified after plant extract treatment on cells pre-stimulated with H2O2. Results: A noncytotoxic dose (200 µM of H2O2 induced active mRNA expression of COX2, IL1β, NFE2L2, NFκB1, NFκB2, NOS2, and TNFα, while PPARγ was depressed. The expression of all genes tested was significantly (P<0.001 regulated by plant extracts after pre-stimulation with H2O2. COX2 was downregulated by AL, PG, and VM. All extracts depressed IL1β expression, but upregulated NFE2L2. NFκB1, NFκB2, and TNFα were downregulated by AL, CS, PG, and VM. NOS2 was inhibited by CS, PG, and VM. PPARγ was decreased only after treatment with E. angustifolia and E. senticosus. Conclusion: The results of the present study indicate that the stimulation of H2O2 on RAW267.4 cells induced the transcription of proinflammatory mediators, showing that this could be an applicable system by which to activate macrophages. Plant extracts from AL, CS, PG, and VM possess in vitro anti-inflammatory activity on H2O2-stimulated macrophages by modulating key inflammation mediators. Further in

  2. Photocatalytic degradation of methyl orange: influence of H2O2 in the TiO2-based system.

    Andronic, Luminita; Manolache, Simona; Duta, Anca


    The purpose of this study was to investigate the photocatalytic oxidation of a reactive azo dye. The photocatalytic activity of the TiO2 was studied using a reactor equipped with UV-A sources, with maximum emission at 365 nm. The photocatalytic activity of the TiO2 powder (99.9% anatase) and thin films has been measured through the decomposition of methyl orange solutions. The thin film was prepared by doctor blade and spray pyrolysis deposition (SPD). The TiO2 suspensions were prepared at 1 g/L concentration, and the initial methyl orange concentration was fixed at 7.8125 mg/L. The influence of the TiO2 (powder or thin films) and/or O2 and H2O2 on the photobleaching rate, was tested under different experiments, at pH = 5. Thin films (doctor blade) of TiO2 formed of mezo-sized aggregates formed of nanosized anatase crystallites show better photobleaching efficiency than thin film (SPD) due to their large internal surface. The rate is even higher in H2O2 compared to oxygen environment.

  3. Phosphorus recovery from biogas slurry by ultrasound/H2O2 digestion coupled with HFO/biochar adsorption process.

    He, Xuemeng; Zhang, Tao; Ren, Hongqiang; Li, Guoxue; Ding, Lili; Pawlowski, Lucjan


    Phosphorus (P) recovery from biogas slurry has recently attracted considerable interest. In this work, ultrasound/H2O2 digestion coupled with ferric oxide hydrate/biochar (HFO/biochar) adsorption process was performed to promote P dissolution, release, and recovery from biogas slurry. The results showed that the optimal total phosphorus release efficiency was achieved at an inorganic phosphorus/total phosphorus ratio of 95.0% at pH 4, 1mL of added H2O2, and ultrasonication for 30min. The P adsorption by the HFO/biochar followed pseudo second-order kinetics and was mainly controlled by chemical processes. The Langmuir-Freundlich model matched the experimental data best for P adsorption by HFO/biochar at 298 and 308K, whereas the Freundlich model matched best at 318K. The maximum amount of P adsorbed was 220mg/g. The process was endothermic, spontaneous, and showed an increase in disorder at the solid-liquid interface. The saturated adsorbed HFO/biochar continually releases P and is most suitable for use in an alkaline environment. The amount of P released reached 29.1mg/g after five extractions. P mass balance calculation revealed that 11.3% of the total P can be made available. Copyright © 2016. Published by Elsevier Ltd.

  4. Degradation and mineralization of organic UV absorber compound 2-phenylbenzimidazole-5-sulfonic acid (PBSA) using UV-254nm/H2O2.

    Abdelraheem, Wael H M; He, Xuexiang; Duan, Xiaodi; Dionysiou, Dionysios D


    Various studies have revealed the non-biodegradable and endocrine disrupting properties of sulfonated organic UV absorbers, directing people's attention toward their risks on ecological and human health and hence their removal from water. In this study, UV-254nm/H2O2 advanced oxidation process (AOP) was investigated for degrading a model UV absorber compound 2-phenylbenzimidazole-5-sulfonic acid (PBSA) and a structurally similar compound 1H-benzimidazole-2-sulfonic acid (BSA), with a specific focus on their mineralization. At 4.0mM [H2O2]0, a complete removal of 40.0μM parent PBSA and 25% decrease in TOC were achieved with 190min of UV irradiation; SO4(2-) was formed and reached its maximum level while the release of nitrogen as NH4(+) was much lower (around 50%) at 190min. Sulfate removal was strongly enhanced by increasing [H2O2]0 in the range of 0-4.0mM, with slight inhibition in 4.0-12.0mM. Faster and earlier ammonia formation was observed at higher [H2O2]0. The presence of Br(-) slowed down the degradation and mineralization of both compounds while a negligible effect on the degradation was observed in the presence of Cl(-). Our study provides important technical and fundamental results on the HO based degradation and mineralization of SO3H and N-containing UV absorber compounds.

  5. Herschel Far-Infrared Spectral-mapping of Orion BN/KL Outflows: Spatial distribution of excited CO, H2O, OH, O and C+ in shocked gas

    Goicoechea, Javier R; Cernicharo, Jose; Neufeld, David A; Vavrek, Roland; Bergin, Edwin A; Cuadrado, Sara; Encrenaz, Pierre; Etxaluze, Mireya; Melnick, Gary J; Polehampton, Edward


    We present ~2'x2' spectral-maps of Orion BN/KL outflows taken with Herschel at ~12'' resolution. For the first time in the far-IR domain, we spatially resolve the emission associated with the bright H2 shocked regions "Peak 1" and "Peak 2" from that of the Hot Core and ambient cloud. We analyze the ~54-310um spectra taken with the PACS and SPIRE spectrometers. More than 100 lines are detected, most of them rotationally excited lines of 12CO (up to J=48-47), H2O, OH, 13CO, and HCN. Peaks 1/2 are characterized by a very high L(CO)/L(FIR)~5x10^{-3} ratio and a plethora of far-IR H2O emission lines. The high-J CO and OH lines are a factor ~2 brighter toward Peak 1 whereas several excited H2O lines are ~50% brighter toward Peak 2. A simplified non-LTE model allowed us to constrain the dominant gas temperature components. Most of the CO column density arises from Tk~200-500 K gas that we associate with low-velocity shocks that fail to sputter grain ice mantles and show a maximum gas-phase H2O/CO~10^{-2} abundance r...

  6. Dormancy removal of apple seeds by cold stratification is associated with fluctuation in H2O2, NO production and protein carbonylation level.

    Dębska, Karolina; Krasuska, Urszula; Budnicka, Katarzyna; Bogatek, Renata; Gniazdowska, Agnieszka


    Reactive oxygen (ROS) and nitrogen (RNS) species play a signaling role in seed dormancy alleviation and germination. Their action may be described by the oxidative/nitrosative "window/door". ROS accumulation in embryos could lead to oxidative modification of protein through carbonylation. Mature apple (Malus domestica Borkh.) seeds are dormant and do not germinate. Their dormancy may be overcome by 70-90 days long cold stratification. The aim of this work was to analyze the relationship between germinability of embryos isolated from cold (5°C) or warm (25°C) stratified apple seeds and ROS or nitric oxide (NO) production and accumulation of protein carbonyl groups. A biphasic pattern of variation in H2O2 concentration in the embryos during cold stratification was detected. H2O2 content increased markedly after 7 days of seeds imbibition at 5°C. After an additional two months of cold stratification, the H2O2 concentration in embryos reached the maximum. NO production by the embryos was low during entire period of stratification, but increased significantly in germination sensu stricto (i.e. phase II of the germination process). The highest content of protein carbonyl groups was detected after 6 weeks of cold stratification treatment. Fluctuation of H2O2 and protein carbonylation seems to play a pivotal role in seed dormancy alleviation by cold stratification, while NO appears to be necessary for seed germination.

  7. Global Potential Energy Minima of (H$_{2}$O)$_{n}$ Clusters on Graphite

    Gonzalez, B S; Breton, J; Llorente, J M Gomez


    Likely candidates for the global potential energy minima of (H$_{2}$O)$_{n}$ clusters with $n\\leq21$ on the (0001)-surface of graphite are found using basin-hopping global optimization. The potential energy surfaces are constructed using the TIP4P intermolecular potentials for the water molecules (the TIP3P is also explored as a secondary choice), a Lennard-Jones water-graphite potential, and a water-graphite polarization potential that is built from classical electrostatic image methods and takes into account both the perpendicular and parallel electric polarizations of graphite. This potential energy surface produces a rather hydrophobic water-graphite interaction. As a consequence, the water component of the lowest graphite-(H$_{2}$O)$_{n}$ minima is quite closely related to low-lying minima of the corresponding TIP4P (H$_{2}$O)$_{n}$ clusters. In about half of the cases the geometrical substructure of the water molecules in the graphite-(H$_{2}$O)$_{n}$ global minimum coincides with that of the correspond...

  8. High concentrations of H2O2 make aerobic glycolysis energetically more favourable than cellular respiration.

    Hamid R Molavian


    Full Text Available Since the original observation of the Warburg Effect in cancer cells, over eight decades ago, the major question of why aerobic glycolysis is favored over oxidative phosphorylation has remained unresolved. An understanding of this phenomenon may well be the key to the development of more effective cancer therapies. In this paper, we use a semi-empirical method to throw light on this puzzle. We show that aerobic glycolysis is in fact energetically more favorable than oxidative phosphorylation for concentrations of peroxide (H2O2 above some critical threshold value. The fundamental reason for this is the activation and high engagement of the pentose phosphate pathway (PPP in response to the production of reactive oxygen species H2O2 by mitochondria and the high concentration of H2O2 (produced by mitochondria and other sources. This makes oxidative phosphorylation an inefficient source of energy since it leads (despite high levels of ATP production to a concomitant high energy consumption in order to respond to the hazardous waste products resulting from cellular processes associated with this metabolic pathway. We also demonstrate that the high concentration of H2O2 results in an increased glucose consumption, and also increases the lactate production in the case of glycolysis.

  9. H 2O 2 and radiation induced dissolution of UO 2 and SIMFUEL pellets

    Nilsson, Sara; Jonsson, Mats


    Dissolution of the UO 2 matrix is of major importance in the safety assessment of a future deep repository for spent nuclear fuel. The aim of this work is to elucidate if the observed differences in dissolution rates between SIMFUEL and UO 2 can be attributed to differences in oxidant reactivity towards these two materials. To elucidate this, the oxidative dissolution of U(VI) and consumption of H 2O 2 have been studied for UO 2 and SIMFUEL pellets under N 2 and H 2 atmosphere. The H 2O 2 and U(VI) concentrations have been measured as a function of reaction time. In addition, γ-radiation induced dissolution UO 2 and SIMFUEL pellets have been studied. The experiments show that while the reactivity of the two types of pellets towards H 2O 2 is almost identical and in good agreement with the previously determined rate constant for the reaction, the dissolution rates differ considerably. The significantly lower rate of dissolution of the SIMFUEL pellet is attributed to an increased fraction of catalytic decomposition of H 2O 2. The radiation chemical experiments reveal a similar but less pronounced difference between the two types of pellets. This implies that the relative impact of the radiolytic oxidants in radiation induced UO 2 dissolution differs between a pure UO 2 pellet and SIMFUEL.

  10. Chandra and XMM–Newton Observations of H2O Maser Galaxy Mrk 348

    J. Wang; J. S. Zhang; Q. Guo


    For H2O megamaser galaxy Mrk 348, Chandra and XMM–Newton data are analysed. The nuclear fitting results of XMM–Newton data suggest the possible existence of a heavily obscured AGN. But the nuclear spectrum extracted from Chandra cannot be well-fitted by the best fitting model for XMM–Newton. Further optimal fitting and discussions are needed.

  11. Chandra and XMM–Newton Observations of H2O Maser Galaxy Mrk 266

    J. Wang; J. S. Zhang; J. H. Fan


    For H2O megamaser galaxy Mrk 266, its Chandra and XMM–Newton data are analyzed here. It shows existence of two obscured nuclei (separation is ∼ 5''). Our preferred model, the high energy reflected model can fit the hard component of both nuclei spectra well.

  12. Mechanisms in manganese catalysed oxidation of alkenes with H2O2

    Saisaha, Pattama; de Boer, Johannes W.; Browne, Wesley R.


    The development of new catalytic systems for cis-dihydroxylation and epoxidation of alkenes, based on atom economic and environmentally friendly concepts, is a major contemporary challenge. In recent years, several systems based on manganese catalysts using H2O2 as the terminal oxidant have been dev

  13. Enabling direct H2O2 production through rational electrocatalyst design

    Siahrostami, Samira; Verdaguer Casadevall, Arnau; Karamad, Mohammadreza;


    electrocatalysts are needed. Using density functional theory calculations, we identify Pt-Hg as a promising candidate. Electrochemical measurements on Pt-Hg nanoparticles show more than an order of magnitude improvement in mass activity, that is, A g(-1) precious metal, for H2O2 production, over the best...

  14. High purity H2/H2O/Ni/SZ electrodes at 500º C

    Høgh, Jens Valdemar Thorvald; Hansen, Karin Vels; Norrman, Kion


    of stabilized zirconia (SZ) with 10, 13 and 18 mol% yttria and one with 6 mol% scandia plus 4 mol% yttria were studied at open circuit voltage at 400-500 C in mixtures of H2/H2O over 46 days. The polarization resistances (Rp) for all samples increased significantly during the first 10-20 days at 500 C...

  15. Fall and Rise of a D$_2$O Ice Cube in Liquid H$_2$O


    The demonstration described in this article is to show thatwhile H$_2$O ice floats in water, D$_2$O ice sinks in water, provingthe higher density of ‘heavy water’. This experiment can bedone in a classroom or in an auditoriam.

  16. H2O2 inhibits ABA-signaling protein phosphatase HAB1.

    Madhuri Sridharamurthy

    Full Text Available Due to its ability to be rapidly generated and propagated over long distances, H2O2 is an important second messenger for biotic and abiotic stress signaling in plants. In response to low water potential and high salt concentrations sensed in the roots of plants, the stress hormone abscisic acid (ABA activates NADPH oxidase to generate H2O2, which is propagated in guard cells in leaves to induce stomatal closure and prevent water loss from transpiration. Using a reconstituted system, we demonstrate that H2O2 reversibly prevents the protein phosphatase HAB1, a key component of the core ABA-signaling pathway, from inhibiting its main target in guard cells, SnRK2.6/OST1 kinase. We have identified HAB1 C186 and C274 as H2O2-sensitive thiols and demonstrate that their oxidation inhibits both HAB1 catalytic activity and its ability to physically associate with SnRK2.6 by formation of intermolecular dimers.

  17. Morroniside protects SK-N-SH human neuroblastoma cells against H2O2-induced damage.

    Zhang, Jing-Xing; Wang, Rui; Xi, Jin; Shen, Lin; Zhu, An-You; Qi, Qi; Wang, Qi-Yi; Zhang, Lun-Jun; Wang, Feng-Chao; Lü, He-Zuo; Hu, Jian-Guo


    Oxidative stress-induced cell injury has been linked to the pathogenesis of neurodegenerative disorders such as spinal cord injury, Parkinson's disease, and multiple sclerosis. Morroniside is an antioxidant derived from the Chinese herb Shan-Zhu-Yu. The present study investigated the neuroprotective effect of morroniside against hydrogen peroxide (H2O2)-induced cell death in SK-N-SH human neuroblastoma cells. H2O2 increased cell apoptosis, as determined by flow cytometry and Hoechst 33342 staining. This effect was reversed by pretreatment with morroniside at concentrations of 1-100 µM. The increase in intracellular reactive oxygen species (ROS) generation and lipid peroxidation induced by H2O2 was also abrogated by morroniside. H2O2 induced a reduction in mitochondrial membrane potential, increased caspase-3 activity, and caused downregulation of B cell lymphoma-2 (Bcl-2) and upregulation of Bcl-2-associated X protein (Bax) expression. These effects were blocked by morroniside pretreatment. Thus, morroniside protects human neuroblastoma cells against oxidative damage by inhibiting ROS production while suppressing Bax and stimulating Bcl-2 expression, thereby blocking mitochondrial-mediated apoptosis. These results indicate that morroniside has therapeutic potential for the prevention and treatment of neurodegenerative diseases.

  18. Dysregulated autophagy increased melanocyte sensitivity to H2O2-induced oxidative stress in vitiligo

    He, Yuanmin; Li, Shuli; Zhang, Weigang; Dai, Wei; Cui, Tingting; Wang, Gang; Gao, Tianwen; Li, Chunying


    In vitiligo, melanocytes are particularly vulnerable to oxidative stress owing to the pro-oxidant state generated during melanin synthesis and to the genetic antioxidant defects. Autophagy is a controlled self-digestion process which can protect cells against oxidative damage. However, the exact role of autophagy in vitiligo melanocytes in response to oxidative stress and the mechanism involved are still not clear. To determine the implications of autophagy for melanocyte survival in response to oxidative stress, we first detected the autophagic flux in normal melanocytes exposure to H2O2, and found that autophagy was significantly enhanced in normal melanocytes, for protecting cells against H2O2-induced oxidative damage. Nevertheless, vitiligo melanocytes exhibited dysregulated autophagy and hypersensitivity to H2O2-induced oxidative injury. In addition, we confirmed that the impairment of Nrf2-p62 pathway is responsible for the defects of autophagy in vitiligo melanocytes. Noteworthily, upregulation of the Nrf2-p62 pathway or p62 reduced H2O2-induced oxidative damage of vitiligo melanocytes. Therefore, our data demonstrated that dysregulated autophagy owing to the impairment of Nrf2-p62 pathway increase the sensitivity of vitiligo melanocytes to oxidative stress, thus promote the development of vitiligo. Upregulation of p62-dependent autophagy may be applied to vitiligo treatment in the future. PMID:28186139

  19. Dense Molecular Gas and H2O Maser Emission in Galaxies

    F. Huang; J. S. Zhang; R. M. Li; H. K. Li


    Extragalactic H2O masers have been found in dense gas circumstance in off-nuclear star formation regions or within parsecs of Active Galactic Nuclei (AGNs). HCN molecular (one of the best dense gas tracers) Emission has been detected in more than 60 galaxies. For HCN-detected galaxy sample, the relation of maser and gas emission was investigated here to identify physical observable properties that differentiate maser and non-maser galaxies. Our analysis results show that there is no significant difference on the infrared and gas emission between maser galaxies and galaxies without maser detection. For maser host HCN-galaxies, maser luminosity is found to be correlated to CO luminosity (a proxy of the total molecular gas) and HCN luminosity, i.e., kilomasers (H2O < 10⊙) with low maser luminosity having low gas emission luminosity, with respect to megamasers (H2O > 10⊙). For normalized maser and HCN luminosity (for removing distance effect), the correlation is still apparent. However, for normalized maser and CO luminosity, the correlation disappeared completely. Thus one proposition that the amount of dense molecular gas should be a good tracer of H2O maser emission can be made.

  20. Chandra Data Analysis of H2O Megamaser Galaxy NGC 4258

    Baisheng Liu; Jiangshui Zhang; Jin Wang


    Chandra observations of NGC 4258 were analyzed to investigate the circumnuclear environment of the H2O megamaser galaxy. Its adaptively-smoothed image shows a bright nucleus and another weak source nearby. For the maser host nucleus, our preferred fitting of its spectra gives the absorption of ∼ 7 × 1022cm-2.

  1. Pretreatment of seed with H2O2 enhances drought tolerance of ...



    Nov 16, 2009 ... including higher net photosynthetic rate, leaf area and dry weight. Moreover, H2O2 .... m-2s-1 light intensity at leaf surface and 50 - 55% relative humidity ... The reaction mixture contained 25 mM potassium phosphate buffer.

  2. H2O/CO2 co-electrolysis in solid oxide electrolysis cells

    Han Minfang; Fan Hui; Peng Suping


    A solid oxide electrolysis cell (SOEC) is an environmental-friendly device which can convert electric energy into chemical energy with high efficiency. In this paper,the progress on structure and operational princi-ple of an SOEC for co-electrolyzing H2O and CO2 to generate syngas was reviewed. The recent development of high temperature H2O/CO2 co-electrolysis from solid oxide single electrolysis cell was introduced. Also investi-gated was H2O/CO2 co-electrolysis research using hydrogen electrode-supported nickel (Ni)-yttria-stabilized zir-conia (YSZ)/YSZ/Sr-doped LaMnO3 (LSM)-YSZ cells in our group. With 50%H2O,15.6%H2 and 34.4%CO2 inlet gas to Ni-YSZ electrode,polarization curves (I-U curves) and electrochemical impedance spectra (EIS) were measured at 800℃and 900℃. Long-term durability of electrolysis was carried out with the same in-let gas at 900℃and 0.2 A/cm2. In addition,the improvement of structure and development of novel materials for increasing the electrolysis efficiency of SOECs were put forward as well.

  3. Diagnosing shock temperature with NH$_3$ and H$_2$O profiles

    Gómez-Ruiz, A I; Viti, S; Jiménez-Serra, I; Navarra, G; Bachiller, R; Caselli, P; Fuente, A; Gusdorf, A; Lefloch, B; Lorenzani, A; Nisini, B


    In a previous study of the L1157 B1 shocked cavity, a comparison between NH$_3$(1$_0$-$0_0$) and H$_2$O(1$_{\\rm 10}$--1$_{\\rm 01}$) transitions showed a striking difference in the profiles, with H$_2$O emitting at definitely higher velocities. This behaviour was explained as a result of the high-temperature gas-phase chemistry occurring in the postshock gas in the B1 cavity of this outflow. If the differences in behaviour between ammonia and water are indeed a consequence of the high gas temperatures reached during the passage of a shock, then one should find such differences to be ubiquitous among chemically rich outflows. In order to determine whether the difference in profiles observed between NH$_3$ and H$_2$O is unique to L1157 or a common characteristic of chemically rich outflows, we have performed Herschel-HIFI observations of the NH$_3$(1$_0$-0$_0$) line at 572.5 GHz in a sample of 8 bright low-mass outflow spots already observed in the H$_2$O(1$_{\\rm 10}$--1$_{\\rm 01}$) line within the WISH KP. We d...

  4. H2O-Rich Interstellar Grain Mantles: An Equilibrium Picture

    Dissly, R. W.; Allen, M.; Anicich, V. G.


    Experiments simulating the codeposition of molecular hydrogen and water ice on interstellar grains demonstrate that amorphous water ice at 12 K can incorporate a substantial amount of H2, up to a molar ratio of H2/H2O=0.53.

  5. Indonesian low rank coal oxidation: The effect of H2O2 concentration and oxidation temperature

    Rahayu, S. S.; Findiati, F.; Aprilia, F.


    Extraction of Indonesian low rank coals by alkaline solution has been performed to isolate the humic substances. Pretreatments of the coals by oxidation using H2O2 prior to extraction are required to have higher yield of humic substances. In the previous research, only the extraction process was considered. Therefore, the effects of reaction temperature and residence time on coal oxidation and composition of extract residues are also investigated in this research. The oxidation temperatures studied were 40°C, 50°C, and 70°C and the H2O2 concentrations studied were 5%, 15%, 20 %, and 30 %. All the oxidation variables were studied for 90 minutes. The results show that the higher the concentration of H2O2 used, the less oxidized coal produced. The same trend was obtained by using higher oxidation temperature. The effect of H2O2 concentration, oxidation temperature and reaction time to the yield of humic substances extraction have positive trends.

  6. Characterization and optimization of cathodic conditions for H2O2 synthesis in microbial electrochemical cells

    Cathode potential and O2 supply methods were investigated to improve H2O2 synthesis in an electrochemical cell, and optimal cathode conditions were applied for microbial electrochemical cells (MECs). Using aqueous O2 for the cathode significantly improved current density, but H2...

  7. UV/H(2)O(2) treatment of drinking water increases post-chlorination DBP formation.

    Dotson, Aaron D; Keen, Volha Olya S; Metz, Debbie; Linden, Karl G


    Ultraviolet (UV) irradiation has become popular as a primary disinfectant because it is very effective against Cryptosporidium and does not directly form regulated disinfection by-products. Higher UV doses and UV advanced oxidation (UV/H2O2) processes are under consideration for the treatment of trace organic pollutants (e.g. pharmaceuticals, personal care products). Despite the disinfection effectiveness of UV light, a secondary disinfectant capable of maintaining a distribution system residual is required to meet current U.S. regulation. This study investigated changes in disinfection by-product (DBP) formation attributed to UV or UV/H2O2 followed by application of free chlorine to quench hydrogen peroxide and provide residual disinfectant. At a UV dose of 1000 mJ/cm(2), trihalomethane (THM) yield increased by up to 4 microg/mg-C and 13 microg/mg-C when treated with low and medium pressure UV, respectively. With the addition of hydrogen peroxide, THM yield increased by up to 25 microg/mg-C (5mg-H2O2/L) and 37 microg/mg-C (10 mg-H2O2/L). Although no changes in DBPs are expected during UV disinfection, application of UV advanced oxidation followed by chlorine addition was assessed with regard to impacts on DBP formation.

  8. Aggregation Properties of an Amphiphilic Methanofullerene Derivative in THF-H2O Solvent Mixtures

    Guan Wu WANG; Li Juan JIAO; Er Hong HAO; Yong Ming LU; You Jun YANG


    Amphiphilic methanofullerene 1 exhibits strong tendency to form aggregates in THF-H2O solvent mixtures. Two different aggregation processes induced by either varying the solvent composition or upon standing have been found. Concentration has great influence on the aggregation process. Paralleling to the UV-Vis changes, an unusual solvatochromism has been observed in these two different processes.

  9. Thermodynamic analysis of BiAsO4-H2O

    M. Baikenov


    Full Text Available The present of the work calculated and build up diagram of potential-pH of system BiAsO4-H2O, with using to thermodynamic analysis. There are determined zones of stability of BiAsO4-on tne basis of diagram.

  10. Warm H2O and OH in the disk around the Herbig star HD 163296

    Fedele, D; van Dishoeck, E F; Herczeg, G J; Evans, N J; Bouwman, J; Henning, Th; Green, J


    We present observations of far-infrared (50-200 micron) OH and H2O emission of the disk around the Herbig Ae star HD 163296 obtained with Herschel/PACS in the context of the DIGIT key program. In addition to strong [OI] emission, a number of OH doublets and a few weak highly excited lines of H2O are detected. The presence of warm H2O in this Herbig disk is confirmed by a line stacking analysis, enabled by the full PACS spectral scan, and by lines seen in Spitzer data. The line fluxes are analyzed using an LTE slab model including line opacity. The water column density is 10^14 - 10^15 cm^-2, and the excitation temperature is 200-300 K implying warm gas with a density n > 10^5 cm^-3. For OH we find a column density of 10^14 - 2x10^15 cm^-2 and T_ex ~ 300-500 K. For both species we find an emitting region of r ~ 15-20 AU from the star. We argue that the molecular emission arises from the protoplanetary disk rather than from an outflow. This far-infrared detection of both H2O and OH contrasts with near- and mid-...

  11. Detection of OH$^+$ and H$_2$O$^+$ towards Orion~KL

    Gupta, H; Pearson, J C; Yu, S; Herbst, E; Harada, N; Bergin, E A; Neufeld, D A; Melnick, G J; Bachiller, R; Baechtold, W; Bell, T A; Blake, G A; Caux, E; Ceccarelli, C; Cernicharo, J; Chattopadhyay, G; Comito, C; Cabrit, S; Crockett, N R; Daniel, F; Falgarone, E; Diez-Gonzalez, M C; Dubernet, M -L; Erickson, N; Emprechtinger, M; Encrenaz, P; Gerin, M; Gill, J J; Giesen, T F; Goicoechea, J R; Goldsmith, P F; Joblin, C; Johnstone, D; Langer, W D; Larsson, B; Latter, W B; Lin, R H; Lis, D C; Liseau, R; Lord, S D; Maiwald, F W; Maret, S; Martin, P G; Martin-Pintado, J; Menten, K M; Morris, P; Müller, H S P; Murphy, J A; Nordh, L H; Olberg, M; Ossenkopf, V; Pagani, L; Pérault, M; Phillips, T G; Plume, R; Qin, S -L; Salez, M; Samoska, L A; Schilke, P; Schlecht, E; Schlemmer, S; Szczerba, R; Stutzki, J; Trappe, N; van der Tak, F F S; Vastel, C; Wang, S; Yorke, H W; Zmuidzinas, J; Boogert, A; Güsten, R; Hartogh, P; Honingh, N; Karpov, A; Kooi, J; Krieg, J -M; Schieder, R; Zaal, P


    We report observations of the reactive molecular ions OH$^+$, H$_2$O$^+$, and H$_3$O$^+$ towards Orion KL with Herschel/HIFI. All three $N=1-0$ fine-structure transitions of OH$^+$ at 909, 971, and 1033GHz and both fine-structure components of the doublet {\\it ortho}-H$_2$O$^+$ $1_{11}-0_{00}$ transition at 1115 and 1139GHz were detected; an upper limit was obtained for H$_3$O$^+$. OH$^+$ and H$_2$O$^+$ are observed purely in absorption, showing a narrow component at the source velocity of 9 kms$^{-1}$, and a broad blueshifted absorption similar to that reported recently for HF and {\\it para}-H$_{2}^{18}$O, and attributed to the low velocity outflow of Orion KL. We estimate column densities of OH$^+$ and H$_2$O$^+$ for the 9 km s$^{-1}$ component of $9 \\pm 3 \\times 10^{12}$cm$^{-2}$ and $7 \\pm 2 \\times 10^{12}$cm$^{-2}$, and those in the outflow of $1.9 \\pm 0.7 \\times 10^{13}$cm$^{-2}$ and $1.0 \\pm 0.3 \\times 10^{13}$cm$^{-2}$. Upper limits of $2.4\\times 10^{12}$cm$^{-2}$ and $8.7\\times 10^{12}$cm$^{-2}$ were...

  12. Syntheses, characterization, and luminescence of two lanthanide complexes [Ln2(acetate)6(H2O)4]·4H2O (Ln=Tb(1), Sm(2))

    YU Qiongyan; ZHOU Xiuxia; LIU Maosheng; CHEN Jianqiao; ZHOU Zhengyuan; YIN Xia; CAI Yuepeng


    Two dinuclear compounds [Ln2(acetate)6(H2O)4]·4H2O (Ln=Tb(1), Sm(2)) were obtained by the hydrothermal reaction of Ln2O3 with malonic acid at 150 ℃. Both compounds were characterized by elemental analyses, infrared spectra, and single crystal X-ray diffraction. The results showed that complexes 1 and 2 were isomorphous and crystallize in triclinic space group P(-1). The coordination geometry around Ln(III) ions in the complexes 1 and 2 was a distorted tricapped trigonal prism with a nine coordination. In the crystal, the molecular organization was further stabilized by well-defined weak hydrogen bonding interactions between the neutral dinuclear molecular units that led to the formation of a three-dimensional network. The fluorescence properties of the two complexes 1 and 2 in organic solvents were also studied. The results show that the ligand acetate favored energy transfer to the emitting energy level of Tb(III) in complex 1. Some factors that influence the fluorescent intensity were also discussed in the article.

  13. Solvothermal Synthesis, Crystal Structure and Electrochemical Property of Complex [Co(p-MBA)2(2,2'-bipy)(H2O)]·(H2O)


    One novel complex [Co(p-MBA)2(2,2'-bipy)(H2O)]·(H2O) has been synthesized by the reaction of p-methylbenzoic acid with 2,2'-bipyridine in the solvent mixture of water and methanol. It crystallizes in triclinic, space group P-1 with a=0.70479(14), b=1.1211(2), c=1.6718(3) nm, α=103.806(3), β=90.795(3), γ=104.207(3)°, V=1.2399(4) nm3, Mr=512.41, Dc=1.373 g/cm3, Z=2, F(000)=532, μ=0.733 mm-1, R=0.0432 and wR=0.0957. The crystal structural analysis shows that the cobalt atom is coordinated with three oxygen atoms from two p-methylbenzoic acids and one water molecule and two nitrogen atoms from one 2,2'-bipyridine,forming a distorted square-pyramidal coordination geometry. The cyclic voltammetry behavior of the complex is also reported.

  14. Synthesis and Crystal Structure of a Cyano-bridged Bimetallic Complex [La(betaine)2(H2O)6Fe(CN)6]·2H2O

    LIANG Shu-Hui; CHE Yun-Xia; ZHENG Ji-Min


    The title complex [La(betaine)2(H2O)6Fe(CN)6](2H2O (betaine = (CH3)3NCH2CO2) has been synthesized and characterized by X-ray single-crystal structure analysis. The crystal crystallizes in monoclinic, space group P21/n with a = 15.793(5), b = 8.927(3), c = 22.257(7) (A), β = 110.147(5)°, C16H38FeLaN8O12, Mr = 729.31, Z = 4, V = 2946.0(15) (A)3, Dc = 1.640 g/m3, μ(MoKα) = 1.988 mm-1, F(000) =1476, R = 0.0388 and wR = 0.0827 for 4237 observed reflections (I > 2σ(I)). The La3+ ion is nine-coordinated by one cyano nitrogen atom and eight oxygen atoms of two betaine and six water molecules. Each complex molecule is connected to form a 3D network structure by some O-H…O and O-H…N hydrogen bonds.


    ZHANG Qiang; TANG Ding-xing


    A mixed-ligands complex with the formula of [Cu(R-lact)(o-phen)(H2O)]•4H2O was synthesized by the reaction of copper carbonate with racemic lactic acid (RS-H2lact), and then with o-phenanthroline(o-phen) in ethanol-water(95%) solution. One of the two obtained com-pounds was dark blue column single crystal and was characterized by elemental analysis, IR spectrum and X-ray single crystal diffraction. The crystal belongs to triclinic system with space group P1, a=7.2825(5) , b=11.7322(8) , c=12.1194(8) , a=65.8280(10)°, β=84.2120(10)°,γ=75.3290(10)°, V=913.88(11) 3, Z=2, Dc=1533kg•m-3, Mr=421.89, μ(MoK\\α)=1.240mm-1,λ=0.71073 , the final R=0.0483 and ωR=0.1199 [I﹥2σ(I)] for 3120 observed reflections, F(000)=438. The copper atom is five coordinated with the distorted square pyramid environment. The five coordinated atoms are two oxygen atoms of depronated hydroxyl group and carboxyl of H2lact, two nitrogen atom of o-phen and one oxygen atom of water molecule.

  16. Hydrothermal Synthesis and Structure of a Copper(II) Complex, [Cu(4,4'-bpy)(H2O)3]SO4·2H2O

    林碧洲; 刘培德


    The title complex [Cu(4,4'-bpy)(H2O)3]SO4@2H2O (Mr = 405.86) was synthesized under hydrothermal conditions and its crystal structure has been determined by X-ray diffraction. It crystallizes in the hexagonal system, space group P61 with a = 11.1870(4), c = 21.578(1)(A°), V = 2338.6(2)(A°)3, Dc = 1.729 g/cm3, Z = 6, ((MoKα) = 1.583 mm-1 and F(000) = 1254. The final R and wR are 0.0253 and 0.0416 for 1458 observed reflections with I≥2((I), respectively. It was revealed that the square pyramidal Cu(II) sites are linked through 4,4'-bipyridine groups, forming infinite one-dimensional chains, with the sulfate anions and lattice water molecules occupying the inter-chain positions. During the electrostatic interactions, there exist O...O hydrogen bonds and π-πstacking interactions between the parallel aromatic bipy rings in the structure.

  17. Slow spin relaxation induced by magnetic field in [NdCo(bpdo)(H2O)4(CN)6]⋅3H2O.

    Vrábel, P; Orendáč, M; Orendáčová, A; Čižmár, E; Tarasenko, R; Zvyagin, S; Wosnitza, J; Prokleška, J; Sechovský, V; Pavlík, V; Gao, S


    We report on a comprehensive investigation of the magnetic properties of [NdCo(bpdo)(H2O)4(CN)6]⋅3H2O (bpdo=4, 4'-bipyridine-N,N'-dioxide) by use of electron paramagnetic resonance, magnetization, specific heat and susceptibility measurements. The studied material was identified as a magnet with an effective spin S = 1/2 and a weak exchange interaction J/kB = 25 mK. The ac susceptibility studies conducted at audio frequencies and at temperatures from 1.8 to 9 K revealed that the application of a static magnetic field induces a slow spin relaxation. It is suggested that the relaxation in the magnetic field appears due to an Orbach-like process between the two lowest doublet energy states of the magnetic Nd(3+) ion. The appearance of the slow relaxation in a magnetic field cannot be associated with a resonant phonon trapping. The obtained results suggest that the relaxation is influenced by nuclear spin driven quantum tunnelling which is suppressed by external magnetic field.

  18. The infrared spectra of nitriles and related compounds frozen in Ar and H2O

    Bernstein, M. P.; Sandford, S. A.; Allamandola, L. J.


    We present the 2320-2050 cm-1 (4.31-4.88 micrometers) infrared spectra of 16 solid-state nitriles, isonitriles, and related compounds in order to facilitate the assignment of absorption features in a spectral region now becoming accessible to astronomers for the first time through the Infrared Space Observatory (ISO). This frequency range spans the positions of the strong C triple bond N stretching vibration of these compounds and is inaccessible from the ground due to absorption by CO2 in the terrestrial atmosphere. Band positions, profiles, and intrinsic strengths (A values) were measured for compounds frozen in Ar and H2O matrices at 12 K. The molecular species examined included acetonitrile, benzonitrile (phenylcyanide), 9-anthracenecarbonitrile, dimethylcyanamide, isopropylnitrile (isobutyronitrile), methylacrylonitrile, crotononitrile, acrylonitrile (vinyl cyanide), 3-aminocrotononitrile, pyruvonitrile, dicyandiamide, cyanamide, n-butylisocyanide, methylisocyanoacetate, diisopropylcarbodiimide, and hydrogen cyanide. The C triple bond N stretching bands of the majority of nitriles fall in the 2300-2200 cm-1 (4.35-4.55 micrometers) range and have similar positions in both Ar and H2O matrices, although the bands are generally considerably broader in the H2O matrices. In contrast, the isonitriles and a few exceptional nitriles and related species produce bands at lower frequencies spanning the 2200-2080 cm-1 (4.55-4.81 micrometers) range. These features also have similar positions in both Ar and H2O matrices, and the bands are broader in the H2O matrices. Three of the compounds (pyruvonitrile, dicyandiamide, and cyanamide) show unusually large shifts of their C triple bond N stretching frequencies when changing from Ar to H2O matrices. We attribute these shifts to the formation of H2O:nitrile complexes with these compounds. The implications of these results for the identification of the 2165 cm-1 (4.62 micrometers) "XCN" interstellar feature and the 4550 cm-1 (2

  19. Ab initio study of H2O and water-chain-induced properties of carbon nanotubes

    Agrawal, B. K.; Singh, V.; Pathak, A.; Srivastava, R.


    We perform an ab initio study of the motion of the nano sized water dimer through a single-walled carbon nanotube (SWCNT), the stability of an encapsulated one-dimensional (1D) water chain inside SWCNT, and the H2O -induced structural, energetic, electronic, and optical properties of the SWCNTs. The adsorption of the water molecules is caused by the dispersion forces, i.e., the van der Waals (vdW) interactions. Thus, the role of the vdW interactions in the estimation of the BE for the weakly bound adsorbates cannot be ignored as has been done in several earlier publications. We find that a single H2O molecule or single water dimer or a 1D chain of water dimers is trapped inside the medium-sized (6,6) carbon nanotube placed in vacuum. However, the H2O molecule or water dimer may be transmitted in case the tube is surrounded by water or water vapor at high vapor pressure at high temperatures. On the other hand, a chain of single H2O molecules or more number of the encapsulated H2O molecules is very weakly coupled to the wide (10,10) carbon nanotube and can, thus, easily transmit through the carbon nanotube in agreement with the recent experiments. Further, appreciable adsorption both inside and on the surface of the (10,10) carbon nanotube is predicted in concurrence with the experiments. The small (medium-sized) diameter tubes will adsorb strongly (accommodate) the water molecules outside (inside) the nanotubes. The H2O adsorption converts the conducting small-diameter zigzag (5,0) tube into a semiconductor. Further, the adsorption reduces the band gap of the semiconducting achiral zigzag (10,0) nanotube but increases the band gap of a chiral semiconducting (4,2) tube. The adsorbed H2O molecules increase the electrical conductivity in agreement with the experiment. The overall peak structure in the optical absorption for the pristine tube is not altered significantly by the adsorption except for small alterations in the energy locations and the relative intensities

  20. Role of TRPM2 in H(2O(2-induced cell apoptosis in endothelial cells.

    Lei Sun

    Full Text Available Melastatin-like transient receptor potential channel 2 (TRPM2 is an oxidant-sensitive and cationic non-selective channel that is expressed in mammalian vascular endothelium. Here we investigated the functional role of TRPM2 channels in hydrogen peroxide (H(2O(2-induced cytosolic Ca(2+ ([Ca(2+](i elavation, whole-cell current increase, and apoptotic cell death in murine heart microvessel endothelial cell line H5V. A TRPM2 blocking antibody (TM2E3, which targets the E3 region near the ion permeation pore of TRPM2, was developed. Treatment of H5V cells with TM2E3 reduced the [Ca(2+](i rise and whole-cell current change in response to H(2O(2. Suppressing TRPM2 expression using TRPM2-specific short hairpin RNA (shRNA had similar inhibitory effect. H(2O(2-induced apoptotic cell death in H5V cells was examined using MTT assay, DNA ladder formation analysis, and DAPI-based nuclear DNA condensation assay. Based on these assays, TM2E3 and TRPM2-specific shRNA both showed protective effect against H(2O(2-induced apoptotic cell death. TM2E3 and TRPM2-specific shRNA also protect the cells from tumor necrosis factor (TNF-α-induced cell death in MTT assay. In contrast, overexpression of TRPM2 in H5V cells resulted in an increased response in [Ca(2+](i and whole-cell currents to H(2O(2. TRPM2 overexpression also aggravated the H(2O(2-induced apoptotic cell death. Downstream pathways following TRPM2 activation was examined. Results showed that TRPM2 activity stimulated caspase-8, caspase-9 and caspase-3. These findings strongly suggest that TRPM2 channel mediates cellular Ca(2+ overload in response to H(2O(2 and contribute to oxidant-induced apoptotic cell death in vascular endothelial cells. Down-regulating endogenous TRPM2 could be a means to protect the vascular endothelial cells from apoptotic cell death.

  1. Experimental determination of liquidus H2O contents of haplogranite at deep-crustal conditions

    Makhluf, A. R.; Newton, R. C.; Manning, C. E.


    The liquidus water content of a haplogranite melt at high pressure ( P) and temperature ( T) is important, because it is a key parameter for constraining the volume of granite that could be produced by melting of the deep crust. Previous estimates based on melting experiments at low P (≤0.5 GPa) show substantial scatter when extrapolated to deep crustal P and T (700-1000 °C, 0.6-1.5 GPa). To improve the high-P constraints on H2O concentration at the granite liquidus, we performed experiments in a piston-cylinder apparatus at 1.0 GPa using a range of haplogranite compositions in the albite (Ab: NaAlSi3O8)—orthoclase (Or: KAlSi3O8)—quartz (Qz: SiO2)—H2O system. We used equal weight fractions of the feldspar components and varied the Qz between 20 and 30 wt%. In each experiment, synthetic granitic composition glass + H2O was homogenized well above the liquidus T, and T was lowered by increments until quartz and alkali feldspar crystalized from the liquid. To establish reversed equilibrium, we crystallized the homogenized melt at the lower T and then raised T until we found that the crystalline phases were completely resorbed into the liquid. The reversed liquidus minimum temperatures at 3.0, 4.1, 5.8, 8.0, and 12.0 wt% H2O are 935-985, 875-900, 775-800, 725-775, and 650-675 °C, respectively. Quenched charges were analyzed by petrographic microscope, scanning electron microscope (SEM), X-ray diffraction (XRD), and electron microprobe analysis (EMPA). The equation for the reversed haplogranite liquidus minimum curve for Ab36.25Or36.25Qz27.5 (wt% basis) at 1.0 GPa is T = - 0.0995 w_{{{H}_{ 2} {O}}}^{ 3} + 5.0242w_{{{H}_{ 2} {O}}}^{ 2} - 88.183 w_{{{H}_{ 2} {O}}} + 1171.0 for 0 \\le w_{{{H}_{ 2} {O}}} \\le 17 wt% and T is in °C. We present a revised P - T diagram of liquidus minimum H2O isopleths which integrates data from previous determinations of vapor-saturated melting and the lower pressure vapor-undersaturated melting studies conducted by other workers on

  2. Mapping of [HDO]/[H2O] in the Martian Atmosphere

    Novak, R. E.; Mumma, M. J.; Villanueva, G.; Bonev, B.; Disanti, M.

    Observations of the Martian atmosphere were taken for several seasonal dates at NASA's IRTF using CSHELL. Column densities of HDO and H2O were extracted from individual spectral lines near 3.67 ìm and 3.29 ìm. The slit was positioned N-S on Mars centered at the sub-earth point producing spectral/spatial images. Spectra were extracted at 0.6 arc-sec. intervals and analyzed with models created from GENLN2 atmospheric software; the models include solar Fraunhofer lines, a two-way transmission through Mars' atmosphere, thermal emission from Mars' surface and atmosphere, and a one way transmission through the Earth's atmosphere. From these, latitudinal maps of HDO/H2O were constructed across the observable planet. The HDO/H2O ratios have been found to be larger than those on Earth and they vary with both latitude and season. The higher global HDO/H2O value on Mars compared to that of the Earth is attributed to differential Jeans escape of D and H over geologic time. The ratio in the southern Martian hemisphere is found to be larger than that in the north. This difference could be the signature of Rayleigh distillation, a process in which the different mean temperatures of the polar caps causes a different degree of HDO sequestration resulting in different degrees of enrichment in the polar caps. Detailed results for Ls= 357o in 2006 will be presented when both the HDO and the H2O column densities were obtain from CSHELL data. These will be compared to results from other seasons.Observations of the Martian atmosphere were taken for several seasonal dates at NASA's IRTF using CSHELL. Column densities of HDO and H2O were extracted from individual spectral lines near 3.67 ìm and 3.29 ìm. The slit was positioned N-S on Mars centered at the sub-earth point producing spectral/spatial images. Spectra were extracted at 0.6 arc-sec. intervals and analyzed with models created from GENLN2 atmospheric software; the models include solar Fraunhofer lines, a two-way transmission

  3. Descent Without Modification? The Thermal Chemistry of H2O2 on Europa and Other Icy Worlds

    Loeffler, Mark Josiah; Hudson, Reggie Lester


    The strong oxidant H2O2 is known to exist in solid form on Europa and is suspected to exist on several other Solar System worlds at temperatures below 200 K. However, little is known of the thermal chemistry that H2O2 might induce under these conditions. Here, we report new laboratory results on the reactivity of solid H2O2 with eight different compounds in H2O-rich ices. Using infrared spectroscopy, we monitored compositional changes in ice mixtures during warming. The compounds CH4 (methane), C3H4 (propyne), CH3OH (methanol), and CH3CN (acetonitrile) were unaltered by the presence of H2O2 in ices, showing that exposure to either solid H2O2 or frozen H2O+H2O2 at cryogenic temperatures will not oxidize these organics, much less convert them to CO2. This contrasts strongly with the much greater reactivity of organics with H2O2 at higher temperatures, and particularly in the liquid and gas phases. Of the four inorganic compounds studied, CO, H2S, NH3, and SO2, only the last two reacted in ices containing H2O2, NH3 making NHþ 4 and SO2 making SO2 4 by H+ and e - transfer, respectively. An important astrobiological conclusion is that formation of surface H2O2 on Europa and that molecule's downward movement with H2O-ice do not necessarily mean that all organics encountered in icy subsurface regions will be destroyed by H2O2 oxidation.

  4. Research on the degradation 1,2,4-trichlorobenzene by O3/H2O2/UV process%O3/H2O2/UV降解1,2,4-三氯苯的研究

    孙云娜; 魏东洋; 陆桂英; 贾晓珊; 李杰; 许振成


    采用O3/H2O2/UV工艺处理1,2,4-三氯苯(TCB)模拟废水,考察了TCB初始浓度、pH、H2O2投加量及O3转化率等因素对O3/H2O2/UV降解TCB的影响,推断了TCB可能的降解途径.结果表明:(1)H2O2、O3、UV、O3/H2O2、O3/H2 O2/UV 5种体系对TCB的降解效果为H2O2 <UV<O3 <O3/H2O2 <O3/H2O2/UV.(2)O3/H2O2/UV对TCB降解的单因素实验表明,TCB初始浓度越小、O3转化率越高,TCB去除率越大;H2O2的投加量存在一个最佳值,低于或高于这个最佳值都会导致TCB去除率的下降;在碱性条件下,TCB的降解效果更佳.(3)推测O3/H2O2/UV工艺降解TCB的机制主要为TCB与·OH的反应过程,其历程可分为3步:反应初期阶段,苯环上的C-Cl被·OH攻击,产生羟基化氯苯化合物;苯环得到活化,·OH进攻苯环,产生低氯代苯类物质;羟基化合物破环,生成小分子有机酸.%The O3/H2O2/UV combination process was employed to treat the simulated 1,2,4-trichlorobenzene (TCB) containing wastewater. The effect of initial TCB concentration, pH, H2O2 dosage and ozone transform rate on TCB removal efficiency was investigated. The potential degradation pathway of TCB was proposed with the help of GC,GC/MS and HPLC analysis. Results showed that the removal efficiency of TCB in 5 degradation system (H2O2 , O3,UV,O3/H2O2,O3/H2O2/UV) followed the order of H2O2 <UV<03 <O3/H2O2 <O3/H2 O2/UV. The single-factor test of O3/H2O2/UV degradation system showed that higher TCB removal efficiency always found in system with lower initial TCB efficiency or higher ozone transform rate. H2O2 dosage had an optimum value, below or above the optimum value could reduce the TCB removal efficiency. Alkaline condition of O3/H2O2/UV process was in favor to the TCB degradation. The mechanism of TCB degradation in O3/H2O2/UV system was the reaction between TCB and o OH. In the early stages of degradation, the C-Cl bond in benzene rings was attacked by o OH and produced hy-droxylation chlorobenzene

  5. 水合碱金属离子团簇Rb+(H2O)n和Cs+(H2O)n的量子化学研究%Quantum chemical studies on the hydrated clusters of alkaline-metal cation Rb+ (H2O) n and Cs+ (H2O) n

    宫利东; 龚海丹


    Abstract-.he hydrated clusters of Rb+ (H2O)n and Cs+ (HiO)n(w=l~6) in gas phase were investigated by a high level ab initio method, QCISD/aug-cc-pVDZ. The geometries were optimized. For the lowest-energy structures of the hydra ted clusters, the binding energies and vibrational frequencies were calculated. The results show that as the hydration number of water increases? The distances from the cation to the water oxygen, RM0? And the total binding energies behave the same variation tendency for the Rb+ (H2O), and Cs+ (H2O)n; the charge distribution analysis indicates that the positive charge of the cation decreases gradually, while the negative charge of the water oxygen increases gradually, and the positive charge of the hydrogen does not change evidently.%应用高水平的从头计算方法QCISD/aug-cc-pVDZ,对气相中的Rb+(H2O)n和Cs+(H2O)m(n=1~6)体系进行研究,优化几何构型,对能量最低的结构,计算结合能和振动频率.结果表明,随着水分子数目的增加,对于Rb+和Cs+,RMO和总结合能有相同的变化趋势;电荷分布显示位于离子上的正电荷逐渐减小,位于氧原子上的负电荷逐渐增大,位于氢原子上的正电荷变化不明显.

  6. Promotion of CO oxidation on PdO(101) by adsorbed H2O

    Choi, Juhee; Pan, Li; Mehar, Vikram; Zhang, Feng; Asthagiri, Aravind; Weaver, Jason F.


    We investigated the influence of adsorbed H2O on the oxidation of CO on PdO(101) using temperature programmed reaction spectroscopy (TPRS), reflection absorption infrared spectroscopy (RAIRS) and density functional theory (DFT) calculations. We find that water inhibits CO adsorption on PdO(101) by site blocking, but also provides a more facile pathway for CO oxidation compared with the bare oxide surface. In the presence of adsorbed H2O, the oxidation of CO on PdO(101) produces a CO2 TPRS peak that is centered at a temperature 50 K lower than the main CO2 TPRS peak arising from CO oxidation on clean PdO(101) ( 330 vs. 380 K). RAIRS shows that CO continues to adsorb on atop-Pd sites of PdO(101) when H2O is co-adsorbed, and provides no evidence of other reactive intermediates. DFT calculations predict that the CO oxidation mechanism follows the same steps for CO adsorbed on PdO(101) with and without co-adsorbed H2O, wherein an atop-CO species recombines with an oxygen atom from the oxide surface lattice. According to DFT, hydrogen bonding interactions with adsorbed H2O species stabilize the carboxyl-like transition structure and intermediate that result from the initial recombination of CO and O on the PdO(101) surface. This stabilization lowers the energy barrier for CO oxidation on PdO(101) by 10 kJ/mol, in good agreement with our experimental estimate.

  7. Cost-effectiveness analysis of TOC removal from slaughterhouse wastewater using combined anaerobic-aerobic and UV/H2O2 processes.

    Bustillo-Lecompte, Ciro Fernando; Mehrvar, Mehrab; Quiñones-Bolaños, Edgar


    The objective of this study is to evaluate the operating costs of treating slaughterhouse wastewater (SWW) using combined biological and advanced oxidation processes (AOPs). This study compares the performance and the treatment capability of an anaerobic baffled reactor (ABR), an aerated completely mixed activated sludge reactor (AS), and a UV/H2O2 process, as well as their combination for the removal of the total organic carbon (TOC). Overall efficiencies are found to be up to 75.22, 89.47, 94.53, 96.10, 96.36, and 99.98% for the UV/H2O2, ABR, AS, combined AS-ABR, combined ABR-AS, and combined ABR-AS-UV/H2O2 processes, respectively. Due to the consumption of electrical energy and reagents, operating costs are calculated at optimal conditions of each process. A cost-effectiveness analysis (CEA) is performed at optimal conditions for the SWW treatment by optimizing the total electricity cost, H2O2 consumption, and hydraulic retention time (HRT). The combined ABR-AS-UV/H2O2 processes have an optimal TOC removal of 92.46% at an HRT of 41 h, a cost of $1.25/kg of TOC removed, and $11.60/m(3) of treated SWW. This process reaches a maximum TOC removal of 99% in 76.5 h with an estimated cost of $2.19/kg TOC removal and $21.65/m(3) treated SWW, equivalent to $6.79/m(3) day.

  8. Observation of the novel "three-pointed star" cage-like (H2O)5 cluster in a polymeric solid {[Ag2(bpp)2(H2O)2](chd)·9H2O}n%固态配位聚合物{[Ag2(bpp)2(H2O)2](chd)·9H2O}n中之新颖“三叉星”笼状(H2O)5水簇的发现

    骆耿耿; 熊红波; 傅志勇; 戴劲草


    固态配位聚合物{[Ag2(bpp)2(H2O)2](chd)·9H2O}n(1) (bpp=1,3-二(4-吡啶基)丙烷、H2chd=1,4-环己烷二羧酸)是通过溶液相超声波合成技术获得的,建立在X射线结构分析技术基础上的结构(单斜晶系C2/c空间群,Z=4;晶胞参数a=30.37(2)(A),b=9.271(5)(A),c=18.89(1)(A);β=128.47°;V=4164(4)(A)3)展现出该化合物捕捉了一条有趣的、由“三叉星”笼状五聚体及D2h构型四聚体水簇交替构成的一维水带,该化合物之所以新奇在于其代表了被认为是不太稳定的笼状水五聚体团簇的晶体学范例.第一性原理的密度涵理论(DFT)计算表明,笼状五聚体及D2h构型四聚体水簇的相互连接对于此类欠稳定水簇的稳定性是有益的.%Coordination polymeric solid, {[Ag2(bpp)2(H2O)2](chd)-9H2O}n (1) (bpp = 1,3-bis(4-pyridyl) propane, H2chd = 1,4-cyclo- hexanedicarboxylic acid), has been obtained by the solution phase ultrasonic synthesis techniques. The structure established through X-ray structural analysis shows that the compound traps an interesting ID water tape built by the alternating "three-pointed star" cage-like pentameric and D2h tetrameric clusters (C2/c, Z = 4; a = 30.37(2) A, b = 9.271(5) A, and c = 18.89(1) (A); β = 128.47°; V = 4164(4) (A)3). The novelty of the present complex is the rarely crystallographic example of the cage-shaped water pentamer, which is usually ascribed to a less-stable species. A first-principle density functional theory (DFT) calculation demonstrates that the interconnectivity between cage-like pentamers and D2h, tetramers is beneficial for contribution to the structural stabilization of these less-stable water cluster species.

  9. Impact of Maximum Allowable Cost on CO2 Storage Capacity in Saline Formations.

    Mathias, Simon A; Gluyas, Jon G; Goldthorpe, Ward H; Mackay, Eric J


    Injecting CO2 into deep saline formations represents an important component of many greenhouse-gas-reduction strategies for the future. A number of authors have posed concern over the thousands of injection wells likely to be needed. However, a more important criterion than the number of wells is whether the total cost of storing the CO2 is market-bearable. Previous studies have sought to determine the number of injection wells required to achieve a specified storage target. Here an alternative methodology is presented whereby we specify a maximum allowable cost (MAC) per ton of CO2 stored, a priori, and determine the corresponding potential operational storage capacity. The methodology takes advantage of an analytical solution for pressure build-up during CO2 injection into a cylindrical saline formation, accounting for two-phase flow, brine evaporation, and salt precipitation around the injection well. The methodology is applied to 375 saline formations from the U.K. Continental Shelf. Parameter uncertainty is propagated using Monte Carlo simulation with 10 000 realizations for each formation. The results show that MAC affects both the magnitude and spatial distribution of potential operational storage capacity on a national scale. Different storage prospects can appear more or less attractive depending on the MAC scenario considered. It is also shown that, under high well-injection rate scenarios with relatively low cost, there is adequate operational storage capacity for the equivalent of 40 years of U.K. CO2 emissions.

  10. The Peroxidase/H2O2 System as a Free Radical-Generating Agent for Gelling Maize Bran Arabinoxylans: Rheological and Structural Properties

    Erika Salas-Muñoz


    Full Text Available The oxidative gelation of maize bran arabinoxylans (MBAX using a peroxidase/H2O2 system as a free radical-generating agent was investigated. The peroxidase/H2O2 system led to the formation of dimers and trimer of ferulic acid as covalent cross-link structures in the MBAX network. MBAX gels at 4% (w/v presented a storage modulus of 180 Pa. The structural parameters of MBAX gels were calculated from swelling experiments. MBAX gels presented a molecular weight between two cross-links (Mc, a cross-linking density (ρc and a mesh size (x of 49 × 103 g/mol, 30 × 10−6 mol/cm3 and 193 nm, respectively.

  11. Dramatic enhancement of solar disinfection (SODIS) of wild Salmonella sp. in PET bottles by H2O2 addition on natural water of Burkina Faso containing dissolved iron.

    Sciacca, Frédéric; Rengifo-Herrera, Juliàn A; Wéthé, Joseph; Pulgarin, César


    Disinfection of surface water containing dissolved iron (0.3 mg L(-1)) at natural neutral pH ( approximately 7.5) was carried out via solar disinfection (SODIS) treatment in PET bottles with H(2)O(2) (10 mg L(-1)). Wild coliforms and Salmonella sp. were monitored for 6 h of sunlight irradiation and 72 h of dark post-treatment period. In our conditions, SODIS treatment could not avoid Salmonella sp. re-growth during dark storage, meanwhile the addition of 10 mg L(-1) of H(2)O(2) showed a strong enhancement of the inactivation rate without any re-growth of both bacteria. Finally, total coliforms (Escherichia coli included) demonstrated to be an inappropriate indicator for monitoring bacterial contamination in water during solar disinfection processes.

  12. Inactivation of Bacillus atrophaeus spores in healthcare waste by uv light coupled with H2O2

    M. T. Iannotti


    Full Text Available Healthcare waste inoculated with B. atropheaus spores was used to evaluate a treatment process using UV light in combination with H2O2. First, the influence of the waste mass on the spore inactivation fraction was investigated for a constant radiation exposure time of 10 min and power per unit mass of waste (44-237 W/kg. The degree of inactivation of the spores was then determined as a function of exposure time (5-30 min and power per mass unit (67-178 W/kg for a constant waste mass. The experimental results were adjusted according to four kinetic models. The Hom and power law models were the most appropriate for the description of the disinfection process. The maximum experimental inactivation fraction (95% achieved was obtained with 178 W/kg irradiation for 30 min.

  13. Long-term series of tropospheric water vapour amounts and HDO/H2O ratio profiles above Jungfraujoch.

    Lejeune, B.; Mahieu, E.; Schneider, M.; Hase, F.; Servais, C.; Demoulin, P.


    Water vapour is a crucial climate variable involved in many processes which widely determine the energy budget of our planet. In particular, water vapour is the dominant greenhouse gas in the Earth's atmosphere and its radiative forcing is maximum in the middle and upper troposphere. Because of the extremely high variability of water vapour concentration in time and space, it is challenging for the available relevant measurement techniques to provide a consistent data set useful for trend analyses and climate studies. Schneider et al. (2006a) showed that ground-based Fourier Transform Infrared (FTIR) spectroscopy, performed from mountain observatories, allows for the detection of H2O variabilities up to the tropopause. Furthermore, the FTIR measurements allow the retrieval of HDO amounts and therefore the monitoring of HDO/H2O ratio profiles whose variations act as markers for the source and history of the atmospheric water vapour. In the framework of the MUSICA European project (Multi-platform remote Sensing of Isotopologues for investigating the Cycle of Atmospheric water,, a new approach has been developed and optimized by M. Schneider and F. Hase, using the PROFFIT algorithm, to consistently retrieve tropospheric water vapour profiles from high-resolution ground-based infrared solar spectra and so taking benefit from available long-term data sets of ground-based observations. The retrieval of the water isotopologues is performed on a logarithmic scale from 14 micro-windows located in the 2600-3100 cm-1 region. Other important features of this new retrieval strategy are: a speed dependant Voigt line shape model, a joint temperature profile retrieval and an interspecies constraint for the HDO/H2O profiles. In this contribution, we will combine the quality of the MUSICA strategy and of our observations, which are recorded on a regular basis with FTIR spectrometers, under clear-sky conditions, at the NDACC site

  14. Constraints on the H2O formation mechanism in the wind of carbon-rich AGB stars

    Lombaert, R; Royer, P; de Koter, A; Cox, N L J; González-Alfonso, E; Neufeld, D; De Ridder, J; Agúndez, M; Blommaert, J A D L; Khouri, T; Groenewegen, M A T; Kerschbaum, F; Cernicharo, J; Vandenbussche, B; Waelkens, C


    Context. The recent detection of warm H$_2$O vapor emission from the outflows of carbon-rich asymptotic giant branch (AGB) stars challenges the current understanding of circumstellar chemistry. Two mechanisms have been invoked to explain warm H$_2$O vapor formation. In the first, periodic shocks passing through the medium immediately above the stellar surface lead to H$_2$O formation. In the second, penetration of ultraviolet interstellar radiation through a clumpy circumstellar medium leads to the formation of H$_2$O molecules in the intermediate wind. Aims. We aim to determine the properties of H$_2$O emission for a sample of 18 carbon-rich AGB stars and subsequently constrain which of the above mechanisms provides the most likely warm H$_2$O formation pathway. Methods, Results, and Conclusions. See paper.

  15. H2O in stellar atmospheres. II. ISO spectra of cool red giants and hydrostatic models

    Aringer, B.; Kerschbaum, F.; Jörgensen, U. G.


    We present 26 ISO-SWS spectra taken from a sample of 13 M-type Semiregular, Lb and Mira variables and covering the wavelength range between 2.36 and 5 mu m at a medium resolution. All of the studied objects show intense water bands producing a deep absorption dip around 2.5 mu m. Features of CO, OH, SiO and CO2 are also visible. Using the new H2O linelist published in the first paper of this series and available opacity data for the other important molecules, we calculated a grid of hydrostatic MARCS atmospheres and the corresponding synthetic ISO-SWS spectra. Based on the comparison with these theoretical results the ISO observations can be divided into four classes. The first two groups include the spectra of the Semiregular (SRb) and Lb variables in our sample. For all of them the region between 2.36 and 4.2 mu m can be quite well reproduced by our hydrostatic models. Only the predicted SiO bands above 4 mu m are in some cases too strong which is due to known dynamical effects. Depending on the temperature (above or below 3000 K) of the atmosphere, which mainly determines the intensity of the water depression at 2.5 mu m, the spectra of the Semiregular and Lb variables fall into the first or second class. The third group consists of observations of Mira stars obtained around maximum light where the range between 2.36 and 4.2 mu m can be fitted with our MARCS models except for a strong emission bump appearing in the ISO-SWS data in the region of the SiO features and the slope very close to the short wavelength border. Finally, the last type of spectra corresponds to Mira variables during the phases around the minimum of their visual light curve. For this class the observed water absorption at 2.5 mu m is much more intense than in any hydrostatic atmosphere with a realistic choice of effective temperature and surface gravity. Thus, we conclude that dynamical models are needed to explain the ISO-SWS data of Mira stars. For all of the cooler objects from our sample

  16. A non-equilibrium ortho-to-para ratio of H2O in the Orion PDR

    Choi, Yunhee; van der Tak, Floris; Bergin, Edwin; Plume, Rene


    The ortho-to-para ratio (OPR) of H2O is lower than 1 at low temperature (<15 K) and increases to 3 at high temperature (> 40 K). The OPR of H2O is thus useful to study the formation mechanism of water. The measured OPRs of H2O is 2-3 in solar system comets (Mumma & Charnley, 2011) and in the interst

  17. Evaluation and Optimization of Single Stage Absorption Chiller Using (LiCl + H2O) as the Working Pair

    Kiyan Parham; Ugur Atikol; Mortaza Yari; O. Phillips Agboola


    The thermodynamic performance of the absorption chiller using (H2O + LiCl) as the working pair was simulated and compared with the absorption chiller using (H2O + LiBr). The effects of evaporation temperature on the performance coefficient, COP, generation temperature, concentration of strong solution, and flow rate ratio were also analyzed. At the same condensing and absorbing temperature, the simulating results indicated that the performance coefficient for (H2O + LiCl) is approximately equ...

  18. The influence of solar ultraviolet radiation on the photochemical production of H2O2 in the equatorial Atlantic Ocean

    Gerringa, LJA; Rijkenberg, MJA; Timmermans, KR; Buma, AGJ


    Hydrogen peroxide (H2O2) was measured in marine surface waters of the eastern Atlantic Ocean between 25degreesN and 25degreesS. H2O2 concentrations decreased from 80 nM in the north to 20 nM in the south, in agreement with earlier observations. A diel cycle of H2O2 production as a function of sunlig

  19. Use of Enzymatic Biosensors to Quantify Endogenous ATP or H2O2 in the Kidney

    Palygin, Oleg; Levchenko, Vladislav; Evans, Louise C.; Blass, Gregory; Cowley, Allen W.; Staruschenko, Alexander


    Enzymatic microelectrode biosensors have been widely used to measure extracellular signaling in real-time. Most of their use has been limited to brain slices and neuronal cell cultures. Recently, this technology has been applied to the whole organs. Advances in sensor design have made  possible the measuring of cell signaling in blood-perfused in vivo kidneys. The present protocols list the steps needed to measure ATP and H2O2 signaling in the rat kidney interstitium. Two separate sensor designs are used for the ex vivo and in vivo protocols. Both types of sensor are coated with a thin enzymatic biolayer on top of a permselectivity layer to give fast responding, sensitive and selective biosensors. The permselectivity layer protects the signal from the interferents in biological tissue, and the enzymatic layer utilizes the sequential catalytic reaction of glycerol kinase and glycerol-3-phosphate oxidase in the presence of ATP to produce H2O2. The set of sensors used for the ex vivo studies further detected analyte by oxidation of H2O2 on a platinum/iridium (Pt-Ir) wire electrode. The sensors for the in vivo studies are instead based on the reduction of H2O2 on a mediator coated gold electrode designed for blood-perfused tissue. Final concentration changes are detected by real-time amperometry followed by calibration to known concentrations of analyte. Additionally, the specificity of the amperometric signal can be confirmed by the addition of enzymes such as catalase and apyrase that break down H2O2 and ATP correspondingly. These sensors also rely heavily on accurate calibrations before and after each experiment. The following two protocols establish the study of real-time detection of ATP and H2O2 in kidney tissues, and can be further modified to extend the described method for use in other biological preparations or whole organs. PMID:26485400

  20. Kinetics and mechanisms of degradation of chloroacetonitriles by the UV/H2O2 process.

    Ling, Li; Sun, Jianliang; Fang, Jingyun; Shang, Chii


    Haloacetonitriles (HANs) are emerging disinfection by-products (DBPs) that are more toxic than the regulated DBPs and widely found in the chlorinated/chloraminated water. This paper studied kinetics and mechanisms of the degradation of chloroacetonitriles (CANs) by the UV/H2O2 process at pH 6 and 7.5 and H2O2 concentrations of 1 × 10(-3) M, 5 × 10(-3) M and 1 × 10(-2) M. The degradation followed pseudo first-order degradation kinetics. The degradation rate of monochloroacetonitrile (MCAN) remained similar, while those of dichloroacetonitrile (DCAN) and trichloroacetonitrile (TCAN) increased with increasing pH and H2O2 concentrations. The different trends were attributed to the changing contributions of the two major mechanisms: the nucleophilic attack by hydroperoxide ions ( [Formula: see text] ) and the hydroxyl radical (•OH) oxidation. The second-order rate constants of [Formula: see text] towards MCAN, DCAN and TCAN were determined to be 11.8 (±0.62), 4.83 (±0.01) × 10(3), and 2.54 (±0.23) × 10(5) M(-1) s(-1), respectively, while that of •OH were 8.7 × 10(6), 4.4 × 10(6), and degradation of TCAN was mainly attributed to the [Formula: see text] nucleophilic attack, while that of MCAN was dominated by the •OH oxidation. DCAN was degraded by both mechanisms. The nucleophilic attack increased linearly with increasing [Formula: see text] concentration as a result of increasing H2O2 concentration and/or pH, while the •OH oxidation was less dependent on H2O2 concentrations and/or pH. The nucleophilic attack mainly transformed HANs to haloacetamides, while the •OH oxidation dechlorinated HANs. This paper firstly illustrated the importance of the [Formula: see text] nucleophilic attack, in addition to the •OH oxidation, on the CAN degradation in the UV/H2O2 process.

  1. Absolute Line Intensities for the nu6 Band of H2O2.

    Klee; Winnewisser; Perrin; Flaud


    The purpose of this work was to obtain reliable absolute intensities for the nu6 band of H2O2. It was undertaken because strong discrepancies exist between the different nu6 band intensities which are presently available in the literature (A. Perrin, A. Valentin, J.-M. Flaud, C. Camy-Peyret, L. Schriver, A. Schriver, and P. Arcas, J. Mol. Spectrosc. 1995. 171, 358), (R. May, J. Quant. Radiat. Transfer 1991. 45, 267), and (R. L. Sams, personal communication). The method which was chosen in the present work was to measure simultaneously the far-infrared absorptions and the nu6 absorptions of H2O2. Consequently, Fourier transform spectra of H2O2 were recorded at Giessen in a spectral range (370-1270 cm-1) which covers both the R branch of the torsion-rotation band and the P branch of the nu6 band which appear at low and high wavenumbers, respectively. From the low wavenumber data, the partial pressure of H2O2 present in the cell during the recording of the spectra was determined by calibrating the observed absorptions in the torsion-rotation band with intensities computed using the permanent H2O2 dipole moment measured by Stark effect (A. Perrin, J.-M. Flaud, C. Camy-Peyret, R. Schermaul, M. Winnewisser, J.-Y. Mandin, V. Dana, M. Badaoui, and J. Koput, J. Mol. Spectrosc. 1996. 176, 287-296) and [E. A. Cohen and H. M. Pickett, J. Mol. Spectrosc. 1981. 87, 582-583). In the high frequency range, this value of the partial pressure of H2O2 was used to measure absolute line intensities in the nu6 band. Finally, the line intensities in the nu6 band were fitted using the theoretical methods described in detail in our previous works. Using these new results on line intensities together with the line position parameters that we obtained previously, a new synthetic spectra of the nu6 band was generated, leading to a total band intensity of 0.185 x 10(-16) cm-1/( at 296 K. It has to be pointed out that the new line intensities agree to within the experimental

  2. Raman spectrum of the solid electrolytes LiI·H2O and LiI·D2O

    Poulsen, Finn Willy


    The Raman spectra of cubic LiI·H2O and LiI·D2O have been revised. The spectra reveal only internal and librational modes of H2O (D2O). The isotopic ratios νH/νD, are in the range 1.33-1.78......The Raman spectra of cubic LiI·H2O and LiI·D2O have been revised. The spectra reveal only internal and librational modes of H2O (D2O). The isotopic ratios νH/νD, are in the range 1.33-1.78...




    Full Text Available Osteoarthritis (OA, one of the most common joint diseases with unknown etiology, is characterized by the progressive destruction of articular cartilage and the apoptosis of chondrocytes. The purpose of this study is to elucidate the molecular mechanisms of H2O2-mediated rabbit chondrocytes apoptosis. CCK-8 assay showed that H2O2 treatment induced a remarkable reduction of cell viability, which was further verified by the remarkable phosphatidylserine externalization after H2O2 treatment for 1 h, the typical characteristics of apoptosis. H2O2 treatment induced a significant dysfunction of mitochondrial membrane potential (ΔΨm, but did not induce casapse-9 activation, indicating that H2O2 treatment induced caspase-independent intrinsic apoptosis that was further verified by the fact that silencing of AIF but not inhibiting caspase-9 potently prevented H2O2-induced apoptosis. H2O2 treatment induced a significant increase of caspase-8 and -3 activation, and inhibition of caspase-8 or -3 significantly prevented H2O2-induced apoptosis, suggesting that the extrinsic pathway played an important role. Collectively, our findings demonstrate that H2O2 induces apoptosis via both the casapse-8-mediated extrinsic and the caspase-independent intrinsic apoptosis pathways in rabbit chondrocytes.

  4. Evaluation and Optimization of Single Stage Absorption Chiller Using (LiCl + H2O as the Working Pair

    Kiyan Parham


    Full Text Available The thermodynamic performance of the absorption chiller using (H2O + LiCl as the working pair was simulated and compared with the absorption chiller using (H2O + LiBr. The effects of evaporation temperature on the performance coefficient, COP, generation temperature, concentration of strong solution, and flow rate ratio were also analyzed. At the same condensing and absorbing temperature, the simulating results indicated that the performance coefficient for (H2O + LiCl is approximately equal to (H2O + LiBr and the generation temperature was lower than that for (H2O + LiBr. On the other hand, the exergetic efficiency, ECOP, which is based on the second law of thermodynamics, for the absorption chiller using (H2O + LiCl, was more than the system using (H2O + LiBr under the same operating conditions. The absorption chiller cycle was then optimized based on the coefficient of performance. The results show that the coefficient of performance of the absorption chiller, using (H2O + LiBr at the optimum conditions, was around 1.5–2% higher than that of (H2O + LiCl.

  5. Alleviation of drought stress by mycorrhizas is related to increased root H2O2 efflux in trifoliate orange

    Huang, Yong-Ming; Zou, Ying-Ning; Wu, Qiang-Sheng


    The Non-invasive Micro-test Technique (NMT) is used to measure dynamic changes of specific ions/molecules non-invasively, but information about hydrogen peroxide (H2O2) fluxes in different classes of roots by mycorrhiza is scarce in terms of NMT. Effects of Funneliformis mosseae on plant growth, H2O2, superoxide radical (O2·−), malondialdehyde (MDA) concentrations, and H2O2 fluxes in the taproot (TR) and lateral roots (LRs) of trifoliate orange seedlings under well-watered (WW) and drought stress (DS) conditions were studied. DS strongly inhibited mycorrhizal colonization in the TR and LRs, whereas mycorrhizal inoculation significantly promoted plant growth and biomass production. H2O2, O2·−, and MDA concentrations in leaves and roots were dramatically lower in mycorrhizal seedlings than in non-mycorrhizal seedlings under DS. Compared with non-mycorrhizal seedlings, mycorrhizal seedlings had relatively higher net root H2O2 effluxes in the TR and LRs especially under WW, as well as significantly higher total root H2O2 effluxes in the TR and LRs under WW and DS. Total root H2O2 effluxes were significantly positively correlated with root colonization but negatively with root H2O2 and MDA concentrations. It suggested that mycorrhizas induces more H2O2 effluxes of the TR and LRs, thus, alleviating oxidative damage of DS in the host plant. PMID:28176859

  6. The SmartH2O project: a platform supporting residential water management through smart meters and data intensive modeling

    Cominola, A.; Nanda, R.; Giuliani, M.; Piga, D.; Castelletti, A.; Rizzoli, A. E.; Maziotis, A.; Garrone, P.; Harou, J. J.


    Designing effective urban water demand management strategies at the household level does require a deep understanding of the determinants of users' consumption. Low resolution data on residential water consumption, as traditionally metered, can only be used to model consumers' behavior at an aggregate level whereas end uses breakdown and the motivations and individual attitudes of consumers are hidden. The recent advent of smart meters allows gathering high frequency consumption data that can be used both to provide instantaneous information to water utilities on the state of the network and continuously inform the users on their consumption and savings. Smart metered data also allow for the characterization of water end uses: this information, coupled with users' psychographic variables, constitutes the knowledge basis for developing individual and multi users models, through which water utilities can test the impact of different management strategies. SmartH2O is an EU funded project which aims at creating an ICT platform able to (i) capture and store quasi real time, high resolution residential water usage data measured with smart meters, (ii) infer the main determinants of residential water end uses and build customers' behavioral models and (iii) predict how the customer behavior can be influenced by various water demand management strategies, spanning from dynamic water pricing schemes to social awareness campaigns. The project exploits a social computing approach for raising users' awareness about water consumption and pursuing water savings in the residential sector. In this work, we first present the SmartH2O platform and data collection, storage and analysis components. We then introduce some preliminary models and results on total water consumption disaggregation into end uses and single user behaviors using innovative fully automated algorithms and overcoming the need of invasive metering campaigns at the fixture level.

  7. Syntheses and Structural Researches of Yb3+ Complexes with Nitrilotriacetic Acids--Nine-coordinate K3[Yb(nta)2(H2O)]·5H2O and Eight-coordinate Na3[Yb(nta)2]·6H2O Complexes


    Yb3+ complexes with two nitrilotriacetic acid molecules were prepared and their compositions were determined as K3[Yb(nta)2(H2O)]*5H2O and Na3[Yb(nta)2]*6H2O by elemental analyses. Their structures were characterized by single-crystal X-ray diffraction analyses. In complex K3[Yb(nta)2(H2O)]*5H2O, the YbN2O7 part forms a nine-coordinate monocapped square antiprismatic structure. In complex Na3[Yb(nta)2]*6H2O, the YbN2O6 part forms an eight-coordinate square antiprismatic structure. It can be seen that the outer cations (K+ and Na+) greatly affect the coordination number and coordinate structure from these results.

  8. TCF Bleaching of Populus tomentosa Kraft Pulps with H2O2 Pretreatment under Acid Condition


    The process of peroxide bleaching of Populus tomentosa kraft pulp with H2O2 pretreatment under acid condition was studied. The variations of pulp characteristics such as brightness, Kappa number and viscosity during the peroxide bleaching process were discussed and the concept of the A/B value was presented for the first time. The results show that acid pretreatment with H2O2 is essential to improve pulp brightness and avoid viscosity loss. The conclusion is reached that the A/B value has great influence on pulp properties when the total amount of peroxide used in the bleaching process is 2%-5%. Pulp with a high viscosity and brightness can be obtained when A/B is about 0.15.

  9. Effect of H2O2 on the in vitro growth of Mycosphaerella fijiensis Cuban isolate

    María I. Oloriz


    Full Text Available Black leaf streak disease (Mycosphaerella fijiensis Morelet is the main foliar disease of bananas and plantain. One of the possible mechanisms of resistance is the hypersensitive response observed in ‘Calcutta 4’ (Musa AA that involves the formation of reactive oxygen species. In order to determine the effect of H2O2 on the in vitro growth of M. fijiensis Cuban isolate CCIBP-Pf-83, several concentrations added to a culture medium PDB were tested. After seven days of incubation the mycelial dry weight was determined. It was found that with 30 mmol l-1 H2O2 in the culture medium, mycelial growth was stimulated and with 50 up to 100 mmol l-1 it decreased. The results provide elements for understanding plantpathogen interactions in this pathosystem. Key words: black leaf streak disease, in vitro culture, ROS

  10. Ice Grain Collisions in Comparison: CO$_2$, H$_2$O and their Mixtures

    Musiolik, Grzegorz; Jankowski, Tim; Wurm, Gerhard


    Collisions of ice particles play an important role in the formation of planetesimals and comets. In recent work we showed, that CO$_2$ ice behaves like silicates in collisions. The resulting assumption was that it should therefore stick less efficiently than H$_2$O ice. Within this paper a quantification of the latter is presented. We used the same experimental setup to study collisions of pure CO$_2$ ice, pure water ice and 50\\% mixtures by mass between CO$_2$ and water at 80K, 1 mbar and an average particle size of $\\sim 90 \\mu$m. The results show a strong increase of the threshold velocity between sticking and bouncing with increasing water content. This supports the idea that water ice is favorable for early growth phases of planets in a zone within the H$_2$O and the CO$_2$ iceline.

  11. Ab initio potential energy and dipole moment surfaces of the F(-)(H2O) complex.

    Kamarchik, Eugene; Toffoli, Daniele; Christiansen, Ove; Bowman, Joel M


    We present full-dimensional, ab initio potential energy and dipole moment surfaces for the F(-)(H2O) complex. The potential surface is a permutationally invariant fit to 16,114 coupled-cluster single double (triple)/aVTZ energies, while the dipole surface is a covariant fit to 11,395 CCSD(T)/aVTZ dipole moments. Vibrational self-consistent field/vibrational configuration interaction (VSCF/VCI) calculations of energies and the IR-spectrum are presented both for F(-)(H2O) and for the deuterated analog, F(-)(D2O). A one-dimensional calculation of the splitting of the ground state, due to equivalent double-well global minima, is also reported.

  12. A biotic Fe0-H2O system for nitrobenzene removal from groundwater

    Wu, Jinhua; Yin, Weizhao; Gu, Jingjing;


    Batch experiment was conducted to evaluate the capability of a biotic Fe0-H2O for nitrobenzene (NB) removal from groundwater. In this study, iron dosage was 0.25gL-1 throughout the whole experiment and the Fe0-H2O system was amended with 180mgL-1 VSS of mixed culture. The biotic system was tested...... at low concentrations (50mgL-1 as COD) of organic substrates (e.g., ethanol, glucose and sodium acetate) and different concentrations of sulfate, nitrate and dissolved oxygen. The bio-iron system exhibited higher NB removal rate and more AN production. The increasing order of efficiency of tested......), and nitrate showed more significant suppression on NB removal as compared to sulfate. AN elimination occurred during both sulfate-reducing and nitrate-reducing processes and microorganisms got extra reduction capacity from the degradation of AN to reduce nitrate and sulfate, causing the mineralization of NB...

  13. The rate constant for the CO + H2O2 reaction

    Glarborg, Peter; Marshall, Paul


    The rate constant for the reaction CO + H2O2 -> HOCO + OH (R1) at 713 K is determined based on the batch reactor experiments of Baldwin et al. [ R. R. Baldwin, R. W. Walker, S. J. Webster, Combust. Flame 15 (1970) 167] on decomposition of H2O2 sensitized by CO. The value, k(1) (713 K) = 8.1 x 10...... in combustion. The present analysis reconciles the batch reactor data of Baldwin et al. with recent high-level theoretical work on the CO + HO2 reaction.......(2) cm(3) mol(-1) s(-1), is consistent with spin-unrestricted density functional theory. Extrapolation to a wider temperature range through ab initio calculations yields the rate constant k(1) = 3.6 x 10(4)T(2.5) exp(-14425[K]/T) cm(3) mol(-1) s(-1). The reaction is probably of minor importance...

  14. Cyclic mononucleotides modulate potassium and calcium flux responses to H2O2 in Arabidopsis roots

    Ordoñez, Natalia Maria


    Cyclic mononucleotides are messengers in plant stress responses. Here we show that hydrogen peroxide (H2O2) induces rapid net K+-efflux and Ca2+-influx in Arabidopsis roots. Pre-treatment with either 10 μM cAMP or cGMP for 1 or 24 h does significantly reduce net K+-leakage and Ca2+-influx, and in the case of the K+-fluxes, the cell permeant cyclic mononucleotides are more effective. We also examined the effect of 10 μM of the cell permeant 8-Br-cGMP on the Arabidopsis microsomal proteome and noted a specific increase in proteins with a role in stress responses and ion transport, suggesting that cGMP is sufficient to directly and/or indirectly induce complex adaptive changes to cellular stresses induced by H2O2. © 2014 Federation of European Biochemical Societies. Published by Elsevier B.V. All rights reserved.

  15. Thermodynamic calculations in the system CH4-H2O and methane hydrate phase equilibria

    Circone, S.; Kirby, S.H.; Stern, L.A.


    Using the Gibbs function of reaction, equilibrium pressure, temperature conditions for the formation of methane clathrate hydrate have been calculated from the thermodynamic properties of phases in the system CH4-H 2O. The thermodynamic model accurately reproduces the published phase-equilibria data to within ??2 K of the observed equilibrium boundaries in the range 0.08-117 MPa and 190-307 K. The model also provides an estimate of the third-law entropy of methane hydrate at 273.15 K, 0.1 MPa of 56.2 J mol-1 K-1 for 1/n CH4??H 2O, where n is the hydrate number. Agreement between the calculated and published phase-equilibria data is optimized when the hydrate composition is fixed and independent of the pressure and temperature for the conditions modeled. ?? 2006 American Chemical Society.

  16. In situ electrical conductivity measurements of H2O under static pressure up to 28 GPa

    Liu, Bao; Gao, Yang; Han, Yonghao; Ma, Yanzhang; Gao, Chunxiao


    The in situ electrical conductivity measurements on water in both solid state and liquid state were performed under pressure up to 28 GPa and temperature from 77 K to 300 K using a microcircuit fabricated on a diamond anvil cell (DAC). Water chemically ionization mainly contributes to electrical conduction in liquid state, which is in accord with the results obtained under dynamic pressure. Energy band theory of liquid water was used to understand effect of static pressure on electrical conduction of water. The electric conductivity of H2O decreased discontinuously by four orders of magnitude at 0.7-0.96 GPa, indicating water frozen at this P-T condition. Correspondingly, the conduction of H2O in solid state is determined by arrangement and bending of H-bond in ice VI and ice VII. Based on Jaccard theory, we have concluded that the charge carriers of ice are already existing ions and Bjerrum defects.

  17. Transport Parameters For Positive IONS In Pure H2O DC Discharge

    Petrovic, Zoran; Stojanovic, Vladimir; Jovanovic, Jasmina; Maric, Dragana


    Transport properties of positive ions originating from H2O (H2O+, OH+) in DC fields and at the room temperature were calculated by using Monte Carlo simulation technique. Initially, the relevant cross section sets were assessed by using Denpoh-Nanbu theory for resolving between elastic and reactive collision events and then resolving contribution of exothermic processes from available experimental data. Newest experimentally or theoretically determined cross sections were compiled and included wherever possible. We present transport coefficients for low and moderate reduced electric fields E / N (N-gas density) accounting for non-conservative processes. Acknowledgment to Ministry of Education, Science and Technology of Republic Serbia, Projects No. 171037 and 410011.

  18. In situ observations of a high-pressure phase of H2O ice

    Chou, I.-Ming; Blank, J.G.; Goncharov, A.F.; Mao, Ho-kwang; Hemley, R.J.


    A previously unknown solid phase of H2O has been identified by its peculiar growth patterns, distinct pressure-temperature melting relations, and vibrational Raman spectra. Morphologies of ice crystals and their pressure-temperature melting relations were directly observed in a hydrothermal diamond-anvil cell for H2O bulk densities between 1203 and 1257 kilograms per cubic meter at temperatures between -10??and 50??C. Under these conditions, four different ice forms were observed to melt: two stable phases, ice V and ice VI, and two metastable phases, ice IV and the new ice phase. The Raman spectra and crystal morphology are consistent with a disordered anisotropic structure with some similarities to ice VI.

  19. Interference of H2 O2 on COD Test and Removal Method for Advanced Oxidation Process%高级氧化法中H2 O2对COD的测定影响及消除

    郭亮; 焦纬洲; 刘有智; 许承骋; 刘文丽; 李静


    通过测定含不同 H2O2浓度的纯水体系及硝基苯类化合物水样体系的废水化学需氧量(COD),分析发现硝基苯类化合物水样中 H2 O2对 COD 的测量存在正干扰,且具有很好的线性关系。在不引入新的干扰前提下,探讨了相应的 H2 O2消除方法。结果表明,当水样中 H2O2浓度475 mg·L-1,COD 值为747.6 mg·L-1时,改变水样 pH 值为碱性有利于 H2O2的去除;添加二氧化锰催化剂虽然能在较短时间内去除 H2 O2,但可能引入新的干扰物;添加过氧化氢酶在不引入新的干扰情况下可快速去除 H2 O2。当反应时间3 min,分别调节水样 pH 为12、添加二氧化锰、添加过氧化氢酶,水样中 H2 O2去除率为1.2%、45.6%、100%。在相同酶量下处理含不同浓度 H2 O2的水样,H2 O2均可在短时间内被除净。分析表明,添加过氧化氢酶可为快速、高效消除废水中未知浓度 H2O2对 CODCr测定的影响提供一条新的途径。%The chemical oxygen demand( COD)for pure water and nitrobenzene waste water sample containing different content of H2 O2 was measured and the linear interference of H2 O2 concentration on COD test was studied. It shows that with increase of the H2 O2 ,the COD increases. Without new interference,the ways to suppress interference of H2 O2 on COD test were discussed including pH value,manganese dioxide catalyst,and catalase. Results show that the catalase eliminates the influence of H2O2on COD determination effectively,and the alkaline environment is in favor of removing the H2O2 to some extent,and manganese di-oxide catalyst can remove H2 O2 in short time but it may introduce new interferences. When the reaction time is 3 min,by adjus-ing initial liquid pH value of 12,adding manganese dioxide catalyst and catalase,respectively,the H2O2 removal rate can reach 1.2%,45.6% and 100%,indicating that catalase can conveniently remove H2O2 with unknown concentration

  20. Type II skeletal myofibers possess unique properties that potentiate mitochondrial H(2)O(2) generation.

    Anderson, Ethan J; Neufer, P Darrell


    Mitochondrial dysfunction is implicated in a number of skeletal muscle pathologies, most notably aging-induced atrophy and loss of type II myofibers. Although oxygen-derived free radicals are thought to be a primary cause of mitochondrial dysfunction, the underlying factors governing mitochondrial superoxide production in different skeletal myofiber types is unknown. Using a novel in situ approach to measure H(2)O(2) production (indicator of superoxide formation) in permeabilized rat skeletal muscle fiber bundles, we found that mitochondrial free radical leak (H(2)O(2) produced/O(2) consumed) is two- to threefold higher (P < 0.05) in white (WG, primarily type IIB fibers) than in red (RG, type IIA) gastrocnemius or soleus (type I) myofibers during basal respiration supported by complex I (pyruvate + malate) or complex II (succinate) substrates. In the presence of respiratory inhibitors, maximal rates of superoxide produced at both complex I and complex III are markedly higher in RG and WG than in soleus muscle despite approximately 50% less mitochondrial content in WG myofibers. Duplicate experiments conducted with +/-exogenous superoxide dismutase revealed striking differences in the topology and/or dismutation of superoxide in WG vs. soleus and RG muscle. When normalized for mitochondrial content, overall H(2)O(2) scavenging capacity is lower in RG and WG fibers, whereas glutathione peroxidase activity, which is largely responsible for H(2)O(2) removal in mitochondria, is similar in all three muscle types. These findings suggest that type II myofibers, particularly type IIB, possess unique properties that potentiate mitochondrial superoxide production and/or release, providing a potential mechanism for the heterogeneous development of mitochondrial dysfunction in skeletal muscle.

  1. Measurement of the absorp tion spectrum of H2O+ in the visible region


    Together with the 74 lines belonging to (0,9,0)(0,0,0) band, the high-resolution absorption spectrum of H2O+A2A1-X2B1 system was observed in the visible region of 16680-17300 cm-1 using optical heterodyne magnetic rotation enhanced velocity modulation spectroscopy for the first time, which verifies the high sensitivity and high signal to noise ratio (S/N) of this technique.

  2. Copper-catalyzed formic acid synthesis from CO2 with hydrosilanes and H2O.

    Motokura, Ken; Kashiwame, Daiki; Miyaji, Akimitsu; Baba, Toshihide


    A copper-catalyzed formic acid synthesis from CO2 with hydrosilanes has been accomplished. The Cu(OAc)2·H2O-1,2-bis(diphenylphosphino)benzene system is highly effective for the formic acid synthesis under 1 atm of CO2. The TON value approached 8100 in 6 h. The reaction pathway was revealed by in situ NMR analysis and isotopic experiments.

  3. A novel approach towards dethioacetalization reactions with H2O2-SOCl2 system

    Kiumars Bahrami; Mohammad Mehdi Khodaei; Maryam Tajik; Vida Shakibaian


    A simple and efficient protocol for the deprotection of dithioacetal,1,3-dithianes and 1,3-dithiolanes has been developed using H2O2-SOCl2 reagent system.In addition to the absence of overoxidation products for oxidation-prone substrates,high chemoselectivity,the low cost and availability of the reagents,simplicity of the method,short reaction times,and excellent yields can also be considered as strong points for this method.

  4. Detection of Hydrogen Peroxide (H2O2 at ExposedTemperatures for Industrial Processes

    Michael J. Schöning


    Full Text Available An H2O2 sensor for the application in industrial sterilisation processes has beendeveloped. Therefore, automated sterilisation equipment at laboratory scale has beenconstructed using parts from industrial sterilisation facilities. In addition, a software tool hasbeen developed for the control of the sterilisation equipment at laboratory scale. Firstmeasurements with the developed sensor set-up as part of the sterilisation equipment havebeen performed and the sensor has been physically characterised by optical microscopy andSEM.

  5. Crystal structures of two decavanadates(V with pentaaquamanganese(II pendant groups: (NMe42[V10O28{Mn(H2O5}2]·5H2O and [NH3C(CH2OH3]2[V10O28{Mn(H2O5}2]·2H2O

    Maurício P. Franco


    Full Text Available Two heterometallic decavanadate(V compounds, bis(tetramethylammonium decaaquadi-μ4-oxido-tetra-μ3-oxido-hexadeca-μ2-oxido-hexaoxidodimanganese(IIdecavanadate(V pentahydrate, (Me4N2[V10O28{Mn(H2O5}2]·5H2O, A, and bis{[tris(hydroxymethylmethyl]ammonium} decaaquadi-μ4-oxido-tetra-μ3-oxido-hexadeca-μ2-oxido-hexaoxidodimanganese(IIdecavanadate(V dihydrate, [NH3C(CH2OH3]2[V10O28{Mn(H2O5}2]·2H2O, B, have been synthesized under mild reaction conditions in an aqueous medium. Both polyanions present two [Mn(OH25]2+ complex units bound to the decavanadate cluster through oxide bridges. In A, the decavanadate unit has 2/m symmetry, whereas in B it has twofold symmetry. Apart from this, the main differences between A and B rest on the organic cations, tetramethylammonium and [tris(hydroxymethylmethyl]ammonium, respectively, and on the number and arrangement of the water molecules of crystallization. In both compounds, the H atoms from the coordinating water molecules participate in extensive three-dimensional hydrogen-bonding networks, which link the cluster units both directly and through solvent molecules and, in B, through the `tris' cation hydroxyl groups. The cation in B also participates in N—H...O hydrogen bonds. A number of C—H...O interactions are also observed in both structures.

  6. H2O2/UV process for surfactants removal from water

    Melihen, Andrej


    Besides conventional approaches to water and wastewater treatment, we know many of advanced processes that are considered as more efficient ways of treatment. Amongst them have an important role, so called, advanced oxidation processes (AOP’s) that generates highly reactive hydroksyl radicals which degrade and remove a wide specter of biologicaly nondegradable pollutants. While operating a source of UV radiation can be used or not. In present study, H2O2/UV-C treatment was appl...

  7. Lactobacilli inactivate Chlamydia trachomatis through lactic acid but not H2O2.

    Zheng Gong

    Full Text Available Lactobacillus species dominate the microbiome in the lower genital tract of most reproductive-age women. Producing lactic acid and H2O2, lactobacilli are believed to play an important role in prevention of colonization by and growth of pathogens. However, to date, there have been no reported studies characterizing how lactobacilli interact with Chlamydia trachomatis, a leading sexually transmitted bacterium. In this report, we demonstrate inactivation of C. trachomatis infectivity by culture media conditioned by Lactobacillus crispatus, L. gasseri and L. jensenii, known to be dominating organisms in the human vaginal microbiome. Lactobacillus still cultures produced lactic acid, leading to time- and concentration-dependent killing of C. trachomatis. Neutralization of the acidic media completely reversed chlamydia killing. Addition of lactic acid into Lactobacillus-unconditioned growth medium recapitulated the chlamydiacidal activity of conditioned media. The H2O2 concentrations in the still cultures were found to be comparable to those reported for the cervicovaginal fluid, but insufficient to inactivate chlamydiae. Aeration of Lactobacillus cultures by shaking markedly induced H2O2 production, but strongly inhibited Lactobacillus growth and lactic acid production, and thus severely affected acidification, leading to significantly reduced chlamydiacidal efficiency. These observations indicate lactobacilli inactivate chlamydiae primarily through maintaining acidity in a relatively hypoxic environment in the vaginal lumen with limited H2O2, which is consistent with the notion that women with higher vaginal pH are more prone to sexually transmitted C. trachomatis infection. In addition to lactic acid, formic acid and acetic acid also exhibited potent chlamydiacidal activities. Taken together, our findings imply that lowering the vaginal pH through engineering of the vaginal microbiome and other means will make women less susceptible to C

  8. Chronic hypoxia promotes pulmonary artery endothelial cell proliferation through H2O2-induced 5-lipoxygenase.

    Kristi M Porter

    Full Text Available Pulmonary Hypertension (PH is a progressive disorder characterized by endothelial dysfunction and proliferation. Hypoxia induces PH by increasing vascular remodeling. A potential mediator in hypoxia-induced PH development is arachidonate 5-Lipoxygenase (ALOX5. While ALOX5 metabolites have been shown to promote pulmonary vasoconstriction and endothelial cell proliferation, the contribution of ALOX5 to hypoxia-induced proliferation remains unknown. We hypothesize that hypoxia exposure stimulates HPAEC proliferation by increasing ALOX5 expression and activity. To test this, human pulmonary artery endothelial cells (HPAEC were cultured under normoxic (21% O2 or hypoxic (1% O2 conditions for 24-, 48-, or 72 hours. In a subset of cells, the ALOX5 inhibitor, zileuton, or the 5-lipoxygenase activating protein inhibitor, MK-886, was administered during hypoxia exposure. ALOX5 expression was measured by qRT-PCR and western blot and HPAEC proliferation was assessed. Our results demonstrate that 24 and 48 hours of hypoxia exposure have no effect on HPAEC proliferation or ALOX5 expression. Seventy two hours of hypoxia significantly increases HPAEC ALOX5 expression, hydrogen peroxide (H2O2 release, and HPAEC proliferation. We also demonstrate that targeted ALOX5 gene silencing or inhibition of the ALOX5 pathway by pharmacological blockade attenuates hypoxia-induced HPAEC proliferation. Furthermore, our findings indicate that hypoxia-induced increases in cell proliferation and ALOX5 expression are dependent on H2O2 production, as administration of the antioxidant PEG-catalase blocks these effects and addition of H2O2 to HPAEC promotes proliferation. Overall, these studies indicate that hypoxia exposure induces HPAEC proliferation by activating the ALOX5 pathway via the generation of H2O2.

  9. Vitamin D derivatives enhance cytotoxic effects of H2O2 or cisplatin on human keratinocytes.

    Piotrowska, Anna; Wierzbicka, Justyna; Ślebioda, Tomasz; Woźniak, Michał; Tuckey, Robert C; Slominski, Andrzej T; Żmijewski, Michał A


    Although the skin production of vitamin D is initiated by ultraviolet radiation type B (UVB), the role vitamin D plays in antioxidative or pro-oxidative responses remains to be elucidated. We have used immortalized human HaCaT keratinocytes as a model of proliferating epidermal cells to test the influence of vitamin D on cellular response to H2O2 or the anti-cancer drug, cisplatin. Incubation of keratinocytes with 1,25(OH)2D3 or its low calcemic analogues, 20(OH)D3, 21(OH)pD or calcipotriol, sensitized cells to ROS resulting in more potent inhibition of keratinocyte proliferation by H2O2 in the presence of vitamin D compounds. These results were supported by cell cycle and apoptosis analyses, and measurement of the mitochondrial transmembrane potentials (MMP), however some unique properties of individual secosteroids were observed. Furthermore, in HaCaT keratinocytes treated with H2O2, 1,25(OH)2D3, 21(OH)pD and calcipotriol stimulated the expression of SOD1 and CAT genes, but not SOD2, indicating a possible role of mitochondria in ROS-modulated cell death. 1,25(OH)2D3 also showed a short-term, protective effect on HaCaT keratinocytes, as exemplified by the inhibition of apoptosis and the maintenance of MMP. However, with prolonged incubation with H2O2 or cisplatin, 1,25(OH)2D3 caused an acceleration in the death of the keratinocytes. Therefore, we propose that lead vitamin D derivatives can protect the epidermis against neoplastic transformation secondary to oxidative or UV-induced stress through activation of vitamin D-signaling. Furthermore, our data suggest that treatment with low calcemic vitamin D analogues or the maintenance of optimal level of vitamin D by proper supplementation, can enhance the anticancer efficacy of cisplatin. Copyright © 2016 Elsevier Inc. All rights reserved.

  10. Degradation of antibiotics norfloxacin by Fenton, UV and UV/H2O2.

    Santos, Lucilaine Valéria de Souza; Meireles, Alexandre Moreira; Lange, Liséte Celina


    This study aimed to evaluate the degradation of the antibiotic norfloxacin, using direct photolysis (UV), photolysis with hydrogen peroxide (UV/H2O2) and Fenton's oxidation processes. Initially, it was evaluated the behavior of the antibiotic norfloxacin on direct photolysis, in order to see if the process could be a pertinent way to eliminate the drug in water treatment stations. The results showed that the use of direct photolysis was not effective in the degradation of the antibiotic, reaching a degradation rate of 85% and a mineralization rate of 2% in 7 h of reaction; leading to the formation of intermediates products. To optimize the UV treatment, it was used the combined UV/H2O2 process. Several concentrations of hydrogen peroxide (0.7, 1.4, 2.1, 2.8, 3.5 and 4.2 mmol/L) at pH 7 were tested. The concentration of 2.1 mmol/L reached a degradation rate of 100% in 100 min of reaction. Based on this result, the speed of the reaction at pH 2, 3, 5, and 10 was evaluated for that same concentration of H2O2. The shortest reaction time (60 min) was verified at pH 2 and 3. For the treatment using Fenton oxidation, a degradation rate of 60% of the compound and a mineralization rate of 55% was obtained in 60 min. The study revealed that the Fenton oxidation and UV/H2O2 can be used for norfloxacin removal, reaching respectively degradation rates of 100% and 60%, and mineralization rates of 55% and 32%.

  11. Using of Photochemical H2O2/UVC Decontamination Cell for Heavily Polluted Waters

    Žebrák, R.; Mašín, P.; Klusoň, P. (Petr); Krystyník, P. (Pavel)


    The presented contribution focuses on the complex study of the pilot-scale photochemical H2O2/UVC system arranged as the ex-situ decontamination cell for heavily polluted waters (contamination with organic substances. The method principle comprises the rational decomposition of hydrogen peroxide induced by UV-C (254 nm). The produced OH radicals are very efficient oxidation species enabling the direct destruction of wide spectrum of organic compounds (polyaromatic hydrocarbons, chlorinat...


    Serigne Fallou Pouye


    Full Text Available The structure of this salt consists of a 3D structure. The anion interacts with NH2 group of the cation and H2O molecules respectively through N-H---O and O-H---O hydrogen bonds. The anion MoO42- is almost perfectly tetrahedral. The four values of the lengths of Mo- O bonds are all equal to 1.7613 Å (12.

  13. Thermodynamic modelling of a double-effect LiBr-H2O absorption refrigeration cycle

    Iranmanesh, A.; Mehrabian, M. A.


    The goal of this paper is to estimate the conductance of components required to achieve the approach temperatures, and gain insights into a double-effect absorption chiller using LiBr-H2O solution as the working fluid. An in-house computer program is developed to simulate the cycle. Conductance of all components is evaluated based on the approach temperatures assumed as input parameters. The effect of input data on the cycle performance and the exergetic efficiency are investigated.

  14. Cotransport of H+, lactate, and H2O in porcine retinal pigment epithelial cells

    Hamann, Steffen; Kiilgaard, Jens Folke; la Cour, Morten


    ) for the H(+) and lactate fluxes. The data suggest that H(2)O is cotransported along with H(+) and lactate ions in MCT1 localized to the retinal membrane. The study emphasizes the importance of this cotransporter in the maintenance of water homeostasis and pH in the subretinal space of a mammalian tissue...... and supports our previous study performed by an invasive technique in an amphibian tissue....

  15. Multi-Wavelength Studies on H2O Maser Host Galaxies

    J. S. Zhang; J. Wang


    H2O maser emissions have been found in external galaxies for more than 30 years. Main sciences associated with extragalactic H2O masers can be summarized roughly into three parts: maser emission itself, AGN sciences and cosmology exploration. Our work in this field focusses on two projects: X-ray data analysis of individual maser source using X-ray penetrability to explore maser host obscured AGN; multi-wavelength statistical properties of the whole published H2O maser sample. Here their nuclear radio properties were investigated in detail, based on their 6-cm and 20-cm radio observation data. Comparing the radio properties between maser-detected sources and non-detected sources at similar distance scale, we find that: (1) maser host galaxies tend to have higher nuclear radio luminosity; (2) the spectral index of both samples is comparable (∼ 0.6), within the error ranges. In addition, for AGN-maser sources, the isotropic maser luminosity tends to increase with rising radio luminosity. Thus we propose the nuclear radio luminosity as one good indicator for searching AGN-masers in the future.

  16. Nonlinear feedback drives homeostatic plasticity in H2O2 stress response

    Goulev, Youlian; Morlot, Sandrine; Matifas, Audrey; Huang, Bo; Molin, Mikael; Toledano, Michel B; Charvin, Gilles


    Homeostatic systems that rely on genetic regulatory networks are intrinsically limited by the transcriptional response time, which may restrict a cell’s ability to adapt to unanticipated environmental challenges. To bypass this limitation, cells have evolved mechanisms whereby exposure to mild stress increases their resistance to subsequent threats. However, the mechanisms responsible for such adaptive homeostasis remain largely unknown. Here, we used live-cell imaging and microfluidics to investigate the adaptive response of budding yeast to temporally controlled H2O2 stress patterns. We demonstrate that acquisition of tolerance is a systems-level property resulting from nonlinearity of H2O2 scavenging by peroxiredoxins and our study reveals that this regulatory scheme induces a striking hormetic effect of extracellular H2O2 stress on replicative longevity. Our study thus provides a novel quantitative framework bridging the molecular architecture of a cellular homeostatic system to the emergence of nonintuitive adaptive properties. DOI: PMID:28418333

  17. Robertsite, Ca2MnIII3O2(PO43·3H2O

    Marcelo B. Andrade


    Full Text Available Robertsite, ideally Ca2Mn3O2(PO43·3H2O [calcium manganese(III tris(orthophosphate trihydrate], can be associated with the arseniosiderite structural group characterized by the general formula Ca2A3O2(TO43·nH2O, with A = Fe, Mn; T = As, P; and n = 2 or 3. In this study, single-crystal X-ray diffraction data were used to determine the robertsite structure from a twinned crystal from the type locality, the Tip Top mine, Custer County, South Dakota, USA, and to refine anisotropic displacement parameters for all atoms. The general structural feature of robertsite resembles that of the other two members of the arseniosiderite group, the structures of which have previously been reported. It is characterized by sheets of [MnO6] octahedra in the form of nine-membered pseudo-trigonal rings. Located at the center of each nine-membered ring is a PO4 tetrahedron, and the other eight PO4 tetrahedra sandwich the Mn–oxide sheets. The six different Ca2+ ions are seven-coordinated in form of distorted pentagonal bipyramids, [CaO5(H2O2], if Ca—O distances less than 2.85 Å are considered. Along with hydrogen bonding involving the water molecules, they hold the manganese–phosphate sheets together. All nine [MnO6] octahedra are distorted by the Jahn–Teller effect.

  18. Pilot-scale UV/H2O2 study for emerging organic contaminants decomposition.

    Chu, Xiaona; Xiao, Yan; Hu, Jiangyong; Quek, Elaine; Xie, Rongjin; Pang, Thomas; Xing, Yongjie


    Human behaviors including consumption of drugs and use of personal care products, climate change, increased international travel, and the advent of water reclamation for direct potable use have led to the introduction of significant amounts of emerging organic contaminants into the aqueous environment. In addition, the lower detection limits associated with improved scientific methods of chemical analysis have resulted in a recent increase in documented incidences of these contaminants which previously were not routinely monitored in water. Such contaminants may cause known or suspected adverse ecological and/or human health effects at very low concentrations. Conventional drinking water treatment processes may not effectively remove these organic contaminants. Advanced oxidation process (AOP) is a promising treatment process for the removal of most of these emerging organic contaminants, and has been accepted worldwide as a suitable treatment process. In this study, different groups of emerging contaminants were studied for decomposition efficiency using pilot-scale UV/H2O2 oxidation setup, including EDCs, PPCPs, taste and odor (T&O), and perfluorinated compounds. Results found that MP UV/H2O2 AOP was efficient in removing all the selected contaminants except perfluorinated compounds. Study of the kinetics of the process showed that both light absorption and quantum yield of each compound affected the decomposition performance. Analysis of water quality parameters of the treated water indicated that the outcome of both UV photolysis and UV/H2O2 processes can be affected by changes in the feed water quality.

  19. Normalized fluctuations, H2O vs n-hexane: Site-correlated percolation

    Koga, Yoshikata; Westh, Peter; Sawamura, Seiji; Taniguchi, Yoshihiro


    Entropy, volume and the cross fluctuations were normalized to the average volume of a coarse grain with a fixed number of molecules, within which the local and instantaneous value of interest is evaluated. Comparisons were made between liquid H2O and n-hexane in the range from -10 °C to 120 °C and from 0.1 MPa to 500 MPa. The difference between H2O and n-hexane in temperature and pressure dependencies of these normalized fluctuations was explained in terms of the site-correlated percolation theory for H2O. In particular, the temperature increase was confirmed to reduce the hydrogen bond probability, while the pressure appeared to have little effect on the hydrogen bond probability. According to the Le Chatelier principle, however, the putative formation of ``ice-like'' patches at low temperatures due to the site-correlated percolation requirement is retarded by pressure increases. Thus, only in the limited region of low pressure (<300 MPa) and temperature (<60 °C), the fluctuating ice-like patches are considered to persist.

  20. Rotational quenching of rotationally-excited H$_2$O in collisions with He

    Yang, Benhui; Satomi, W; Kimura, M; Stancil, P C


    Theoretical rotational quenching cross sections and rate coefficients of ortho- and para-H$_2$O due to collisions with He atoms are presented. The complete angular momentum close-coupling approach as well as the coupled-states approximation for angular momentum decoupling were applied to solve the scattering problem for a large range of rotationally-excited states of water. Results are obtained for quenching from initial levels 1$_{1,0}$, 2$_{1,2}$, 2$_{2,1}$, 3$_{0,3}$, 3$_{1,2}$, 3$_{2,1}$, 4$_{1,4}$, 3$_{3,0}$, and 4$_{2,3}$ of ortho-H$_2$O and from initial levels 1$_{1,1}$, 2$_{0,2}$, 2$_{1,1}$, 2$_{2,0}$, 3$_{1,3}$, 3$_{2,2}$, 4$_{0,4}$, 4$_{1,3}$, and 3$_{3,1}$ of para-H$_2$O for kinetic energies from 10$^{-5}$ to 10$^4$ cm$^{-1}$. State-to-state and total deexcitation cross sections and rate coefficients for temperatures between 0.1 and 3000 K are reported. The present state-to-state rate coefficients are found to be in good agreement with previous results obtained by Green and coworkers at high temper...

  1. Preparation and Molecular Structure of (SCZ)(TNPG)·2H2O

    CHEN Hong-Yan; ZHANG Tong-Lai; ZHANG Jian-Guo


    The (SCZ)(TNPG)·2H2O prepared by mixing semicarbazide (SCZ) and trinitrophloroglucinol (TNPG) was characterized by elemental analysis and IR measurement, and its crystal structure was determined by X-ray single-crystal diffraction analysis.The crystal belongs to triclinic,0.93966(19), c = 1.1925(2) nm, α = 67.48(3), β = 77.56(3), γ = 78.93(3)°, V = 0.6908(2) nm3, Z = 2,Dc = 1.789 g/cm3, Mr = 373.23, F(000) = 384, S = 0.999 andt(MoKα) = 0.172 mm-1.The final R and wR are 0.0394 and 0.1057 for 1724 observed reflections with I > 2σ(I).It is concluded that (SCZ)(TNPG) 2H2O is an ionic compound composed of a cation SCZ+, an anion TNPG- and two water molecules.The TNPG anion and SCZ+ cation are bonded together by electrostatic attraction and hydrogen bonds, and the compound structure is stable.The thermal decomposition of (SCZ)(TNPG) 2H2O was studied by using TG-DTG and DSC techniques with a heating rate of 10 ℃/min, showing the compound contains one endothermic process of dehydrating stage and two intensive exothermic decomposition stages.The enthalpy of exothermic decomposition reaction is 452.31 kJ/mol.

  2. H2O Megamasers toward Radio-bright Seyfert 2 Nuclei

    Zhang, J. S.; Liu, Z. W.; Henkel, C.; Wang, J. Z.; Coldwell, G. V.


    Using the Effelsberg-100 m telescope, we perform a successful pilot survey on H2O maser emission toward a small sample of radio-bright Seyfert 2 galaxies with a redshift larger than 0.04. The targets were selected from a large Seyfert 2 sample derived from the spectroscopic Sloan Digital Sky Survey Data Release 7 (SDSS-DR7). One source, SDSS J102802.9+104630.4 (z ∼ 0.0448), was detected four times during our observations, with a typical maser flux density of ∼30 mJy and a corresponding (very large) luminosity of ∼1135 L ⊙. The successful detection of this radio-bright Seyfert 2 and an additional tentative detection support our previous statistical results that H2O megamasers tend to arise from Seyfert 2 galaxies with large radio luminosity. The finding provides further motivation for an upcoming larger H2O megamaser survey toward Seyfert 2s with particularly radio-bright nuclei with the basic goal to improve our understanding of the nuclear environment of active megamaser host galaxies. Based on observations with the 100 m telescope of the MPIfR (Max-Planck-Institut für Radioastronomie) at Effelsberg.

  3. OH+ and H2O+ absorption toward PKS1830-211

    Muller, S; Black, J H; Beelen, A; Combes, F; Curran, S; Gerin, M; Guelin, M; Henkel, C; Martin, S; Aalto, S; Falgarone, E; Menten, K M; Schilke, P; Wiklind, T; Zwaan, M A


    We report the detection of OH+ and H2O+ in the z=0.89 absorber toward the lensed quasar PKS1830-211. The abundance ratio of OH+ and H2O+ is used to quantify the molecular hydrogen fraction (fH2) and the cosmic-ray ionization rate of atomic hydrogen (zH) along two lines of sight, located at ~2 kpc and ~4 kpc to either side of the absorber's center. The molecular fraction decreases outwards, from ~0.04 to ~0.02, comparable to values measured in the Milky Way at similar galactocentric radii. For zH, we find values of ~2x10^-14 s^-1 and ~3x10^-15 s^-1, respectively, which are slightly higher than in the Milky Way at comparable galactocentric radii, possibly due to a higher average star formation activity in the z=0.89 absorber. The ALMA observations of OH+, H2O+, and other hydrides toward PKS1830-211 reveal the multi-phase composition of the absorbing gas. Taking the column density ratios along the southwest and northeast lines of sight as a proxy of molecular fraction, we classify the species ArH+, OH+, H2Cl+, H...

  4. Phosphate buffer effects on thermal stability and H2O2-resistance of horseradish peroxidase.

    Asad, Sedigheh; Torabi, Seyed-Fakhreddin; Fathi-Roudsari, Mehrnoosh; Ghaemi, Nasser; Khajeh, Khosro


    Horseradish peroxidase (HRP) has attracted intense research interest due to its potential applications in biotechnological fields. However, inadequate stability under prevalent conditions such as elevated temperatures and H(2)O(2) exposure, has limited its industrial application. In this study, stability of HRP was investigated in the presence of different buffer systems (potassium phosphate and Tris-HCl) and additives. It was shown that the concentration of phosphate buffer severely affects enzyme thermostability in a way that in diluted potassium phosphate buffer (10mM) half-life (from 13 to 35 min at 80 °C) and T(m) (from 73 to 77.5 °C) increased significantly. Among additives tested, trehalose had the most thermostabilizing effect. Exploring the role of glycosylation in stabilizing effect of phosphate buffer, non-glycosylated recombinant HRP was also examined for its thermal and H(2)O(2) stability in both diluted and concentrated phosphate buffers. The recombinant enzyme was more thermally stable in diluted buffer in accordance to glycosylated HRP; but interestingly recombinant HRP showed higher H(2)O(2) tolerance in concentrated buffer.

  5. Redetermination of [EuCl2(H2O6]Cl

    Frank Tambornino


    Full Text Available The crystal structure of the title compound, hexaaquadichloridoeuropium(III chloride, was redetermined with modern crystallographic methods. In comparison with the previous study [Lepert et al. (1983. Aust. J. Chem. 36, 477–482], it could be shown that the atomic coordinates of some O atoms had been confused and now were corrected. Moreover, it was possible to freely refine the positions of the H atoms and thus to improve the accurracy of the crystal structure. [EuCl2(H2O6]Cl crystallizes with the GdCl3·6H2O structure-type, exhibiting discrete [EuCl2(H2O6]+ cations as the main building blocks. The main blocks are linked with isolated chloride anions via O—H...Cl hydrogen bonds into a three-dimensional framework. The Eu3+ cation is located on a twofold rotation axis and is coordinated in the form of a Cl2O6 square antiprism. One chloride anion coordinates directly to Eu3+, whereas the other chloride anion, situated on a twofold rotation axis, is hydrogen bonded to six octahedrally arranged water molecules.

  6. Magnetic fields around evolved stars: further observations of H$_2$O maser polarization

    Leal-Ferreira, M L; Kemball, A; Amiri, N


    We aim to detect the magnetic field and infer its properties around four AGB stars using H$_2$O maser observations. The sample we observed consists of the following sources: the semi-regular variable RT Vir and the Mira variables AP Lyn, IK Tau, and IRC+60370. We observed the 6$_{1,6}-5_{2,3}$ H$_2$O maser rotational transition, in full-polarization mode, to determine its linear and circular polarization. Based on the Zeeman effect, one can infer the properties of the magnetic field from the maser polarization analysis. We detected a total of 238 maser features, in three of the four observed sources. No masers were found toward AP Lyn. The observed masers are all located between 2.4 and 53.0 AU from the stars. Linear and circular polarization was found in 18 and 11 maser features, respectively. We more than doubled the number of AGB stars in which magnetic field has been detected from H$_2$O maser polarization, as our results confirm the presence of fields around IK Tau, RT Vir and IRC+60370. The strength of ...

  7. Nonadiabatic dissociation dynamics in H2O: Competition between rotationally and nonrotationally mediated pathways

    Yuan, Kaijun; Cheng, Yuan; Cheng, Lina; Guo, Qing; Dai, Dongxu; Wang, Xiuyan; Yang, Xueming; Dixon, Richard N.


    The photochemistry of H2O in the VUV region is important in interstellar chemistry. Whereas previous studies of the photodissociation used excitation via unbound states, we have used a tunable VUV photolysis source to excite individual levels of the rotationally structured C̃ state near 124 nm. The ensuing OH product state distributions were recorded by using the H-atom Rydberg tagging technique. Experimental results indicate a dramatic variation in the OH product state distributions and its stereodynamics for different resonant states. Photodissociation of H2O(C̃) in rotational states with k′a = 0 occurs exclusively through a newly discovered homogeneous coupling to the à state, leading to OH products that are vibrationally hot (up to v = 13), but rotationally cold. In contrast, for H2O in rotationally excited states with k′a > 0, an additional pathway opens through Coriolis-type coupling to the B̃ state surface. This yields extremely rotationally hot and vibrationally cold ground state OH(X) and electronically excited OH(A) products, through 2 different mechanisms. In the case of excitation via the 110 ← 000 transition the H atoms for these 2 product channels are ejected in completely different directions. Quantum dynamical models for the C̃-state photodissociation clearly support this remarkable dynamical picture, providing a uniquely detailed illustration of nonadiabatic dynamics involving at least 4 electronic surfaces. PMID:19047628

  8. Protective effect of pomegranate seed oil against H2O2 -induced oxidative stress in cardiomyocytes

    Bihamta, Mehdi; Hosseini, Azar; Ghorbani, Ahmad; Boroushaki, Mohammad Taher


    Objective: It has been well documented that oxidative stress is involved in the pathogenesis of cardiac diseases. Previous studies have shown that pomegranate seed oil (PSO) has antioxidant properties. This study was designed to investigate probable protective effects of PSO against hydrogen peroxide (H2O2)-induced damage in H9c2 cardiomyocytes. Materials and Methods: The cells were pretreated 24 hr with PSO 1 hr before exposure to 200 µM H2O2. Cell viability was evaluated using 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium (MTT) assay. The level of reactive oxygen species (ROS) and lipid peroxidation were measured by fluorimetric methods. Results: H2O2 significantly decreased cell viability which was accompanied by an increase in ROS production and lipid peroxidation and a decline in superoxide dismutase activity. Pretreatment with PSO increased viability of cardiomyocytes and decrease the elevated ROS production and lipid peroxidation. Also, PSO was able to restore superoxide dismutase activity. Conclusion: PSO has protective effect against oxidative stress-induced damage in cardiomyocytes and can be considered as a natural cardioprotective agent to prevent cardiovascular diseases. PMID:28265546

  9. Protective effect of pomegranate seed oil against H2O2 -induced oxidative stress in cardiomyocytes

    Mehdi Bihamta


    Full Text Available Objective: It has been well documented that oxidative stress is involved in the pathogenesis of cardiac diseases. Previous studies have shown that pomegranate seed oil (PSO has antioxidant properties. This study was designed to investigate probable protective effects of PSO against hydrogen peroxide (H2O2-induced damage in H9c2 cardiomyocytes.Materials and Methods: The cells were pretreated 24 hr with PSO 1 hr before exposure to 200 µM H2O2. Cell viability was evaluated using 3-(4,5-dimethylthiazol-2-yl-2,5-diphenyl tetrazolium (MTT assay. The level of reactive oxygen species (ROS and lipid peroxidation were measured by fluorimetric methods.Results: H2O2 significantly decreased cell viability which was accompanied by an increase in ROS production and lipid peroxidation and a decline in superoxide dismutase activity. Pretreatment with PSO increased viability of cardiomyocytes and decrease the elevated ROS production and lipid peroxidation. Also, PSO was able to restore superoxide dismutase activity.Conclusion: PSO has protective effect against oxidative stress-induced damage in cardiomyocytes and can be considered as a natural cardioprotective agent to prevent cardiovascular diseases.

  10. H2O2 Metabolism of Apple Leaves Under Water Stress%水分胁迫下苹果叶片的H2O2代谢

    贾虎森; 李德全



  11. A novel near-infrared fluorescent probe for H2O2 in alkaline environment and the application for H2O2 imaging in vitro and in vivo.

    Liu, Keyin; Shang, Huiming; Kong, Xiuqi; Ren, Mingguang; Wang, Jian-Yong; Liu, Yong; Lin, Weiying


    H2O2 as one of the most important ROS (Reactive Oxygen Species) has more attack activity to biomolecules such as DNA, RNA, protein and enzyme in alkaline environment and leads to a series of disease. However, no attention has been paid to the fluorescent detection of H2O2 in alkaline environment in the past. Herein, we reported the first ratiometric near-infrared fluorescent probe based on a boric acid derivative of Changsha near-infrared dye (CSBOH) for H2O2 detection in alkaline condition and the application for H2O2 imaging in vivo. ICT (intra-molecular charge transfer) mechanism was used in CSBOH to modulate the fluorescence change. The photophysical change of CSBOH was investigated by comparison with a phenol derivative of Changsha near-infrared dye (CSOH), a structural analogue bearing phenol group. In the presence of H2O2, CSBOH exhibited remarkably different fluorescence change at 650 nm and 720 nm when excited by 560 nm and 670 nm light respectively in alkaline buffer and showed high selectivity toward H2O2. Cellular experiments demonstrate that CSBOH can image endogenously generated H2O2 in macrophages and A431 cells. In vivo experiment demonstrates that both CSOH and CSBOH can be used for bio-imaging, and CSBOH can image H2O2 in living animal successfully.

  12. H2O2位于ABA的上游参与葡萄对低温的应答%H2O2 Production was Upstream of the Rise of ABA in Response of Grape to Low Temperature

    刘新; 车永梅; 卢江


    以抗寒性较强的葡萄品种(砧木)贝达1 a生枝条叶片为材料,研究低温胁迫下贝达叶片中H2O2与ABA含量的变化及外源H2O2和抗坏血酸(AsA)对贝达叶片中ABA含量的影响.结果表明:低温胁迫下贝达叶片中H2O2与ABA含量先增加后降低,具有猝发现象,H2O2猝发时间早于ABA;外施一定浓度的H2O2可以促进贝达内源ABA的积累,缓解5℃低温对膜的伤害;而外施H2O2的清除剂AsA显著降低内源ABA的含量.表明H2O2与ABA参与了贝达对低温胁迫的应答,H2O2可能位于ABA的上游.

  13. Characterization of titanium dioxide nanoparticles modified with polyacrylic acid and H2O2 for use as a novel radiosensitizer.

    Morita, Kenta; Miyazaki, Serika; Numako, Chiya; Ikeno, Shinya; Sasaki, Ryohei; Nishimura, Yuya; Ogino, Chiaki; Kondo, Akihiko


    An induction of polyacrylic acid-modified titanium dioxide with hydrogen peroxide nanoparticles (PAA-TiO2/H2O2 NPs) to a tumor exerted a therapeutic enhancement of X-ray irradiation in our previous study. To understand the mechanism of the radiosensitizing effect of PAA-TiO2/H2O2 NPs, analytical observations that included DLS, FE-SEM, FT-IR, XAFS, and Raman spectrometry were performed. In addition, highly reactive oxygen species (hROS) which PAA-TiO2/H2O2 NPs produced with X-ray irradiation were quantified by using a chemiluminescence method and a EPR spin-trapping method. We found that PAA-TiO2/H2O2 NPs have almost the same characteristics as PAA-TiO2. Surprisingly, there were no significant differences in hROS generation. However, the existence of H2O2 was confirmed in PAA-TiO2/H2O2 NPs, because spontaneous hROS production was observed w/o X-ray irradiation. In addition, PAA-TiO2/H2O2 NPs had a curious characteristic whereby they absorbed H2O2 molecules and released them gradually into a liquid phase. Based on these results, the H2O2 was continuously released from PAA-TiO2/H2O2 NPs, and then released H2O2 assumed to be functioned indirectly as a radiosensitizing factor.

  14. Induced peroxidase and cytoprotective enzyme expressions support adaptation of HUVECs to sustain subsequent H2O2 exposure.

    Patel, Hemang; Chen, Juan; Kavdia, Mahendra


    H2O2 mediates autocrine and paracrine signaling in the vasculature and can propagate endothelial dysfunction. However, it is not clear how endothelial cells withstand H2O2 exposure and promote H2O2-induced vascular remodeling. To understand the innate ability of endothelial cells for sustaining excess H2O2 exposure, we investigated the genotypic and functional regulation of redox systems in primary HUVECs following an H2O2 treatment. Primary HUVECs were exposed to transient H2O2 exposure and consistent H2O2 exposure. Following H2O2 treatments for 24, 48 and 72 h, we measured O2(-) production, mitochondrial membrane polarization (MMP), and gene expressions of pro-oxidative enzymes, peroxidase enzymes, and cytoprotective intermediates. Our results showed that the 24 h H2O2 exposure significantly increased O2(-) levels, hyperpolarized MMP, and downregulated CAT, GPX1, TXNRD1, NFE2L2, ASK1, and ATF2 gene expression in HUVECs. At 72 h, HUVECs in both treatment conditions were shown to adapt to reduce O2(-) levels and normalize MMP. An upregulation of GPX1, TXNRD1, and HMOX1 gene expression and a recovery of NFE2L2 and PRDX1 gene expression to control levels were observed in both consistent and transient treatments at 48 and 72 h. The response of endothelial cells to excess levels of H2O2 involves a complex interaction amongst O2(-) levels, mitochondrial membrane polarization and anti- and pro-oxidant gene regulation. As a part of this response, HUVECs induce cytoprotective mechanisms including the expression of peroxidase and antioxidant enzymes along with the downregulation of pro-apoptotic genes. This adaptation assists HUVECs to withstand subsequent exposures to H2O2. Copyright © 2015 Elsevier Inc. All rights reserved.

  15. [Influencing Factors for Hydrolysis of Sewage Sludge Pretreated by Microwave-H2O2-Alkaline Process].

    Jia, Rui-lai; Wei, Yuan-song; Liu, Ji-bao


    Pretreatment can improve carbon source utilization of sludge. In this study, influencing factors of hydrolysis including hydrolysis time, ratio of seed sludge and temperature were investigated for sewage sludge pretreated by microwave-H2O2-alkaline process through batch experiments. Meanwhile, effects of hydrolysis and releasing characteristics of organic matters were also investigated under the optimized conditions. The results showed that the optimal hydrolysis time was 12 h and the optimized inoculum to substrate ratio (I/S) was 0.07. Under optimized conditions (12 h, I/S =0.07), SCOD, soluble proteins, soluble sugars and total VFAs content increased with increasing temperature, reaching the maximum at 65 degrees C. Acetic, propionic and iso-valeric acids were the dominant VFAs produced, and the percentage of acetic acid accounting for total VFAs was between 42.7% and 59.7%. In terms of carbon source composition, SCOD accounted for 37.8%-40.8% of total COD, soluble proteins accounted for 38.3%-41.3% of SCOD, soluble sugars accounted for 9.0%-9.3% of SCOD and total VFAs accounted for 3.3%-5.5% of SCOD. The COD/TN watio was between 15.79 and 16.50 in the sludge supernatant. The results of the three-dimensional fluorescence spectra and apparent molecular weight distributions showed that the fluorescence intensity of tyrosine-like substances in the soluble microbial products was the highest and increased with the increasing temperature in the sludge supernatant. After the sewage sludge was pretreated by microwave-H2O2-OH process, a lot of organic matters were released, including small molecule organics (M 100-350), while after hydrolysis, M, 3000-60,000 organics were degraded.

  16. Biomass reduction of Salvinia molesta exposed to copper sulfate pentahydrate (CuSO4.5H2O

    João Pedro Alves de Azevedo Barros


    Full Text Available Copper in the aquatic ecosystem may remain adsorbed or be incorporated into the biomass and undergo biomagnification causing unwanted effects to aquatic macrophyte communities. This study evaluated the biomass reduction of Salvinia molesta (Mitchell exposed to copper sulphate pentahydrate (CuSO4.5H2O under laboratory conditions. Approximately 20.5 g of fresh mass (FM of S. molesta (0.74 g dry matter, DM were placed in glass tanks with different concentrations (n = 3 of CuSO4.5H2O as follows: 0.0; 2.0; 4.0; 6.0; and 8.0 mg L-1 for 28 days. The dry mass was determined after each seven-day interval over 28 days and submitted to repeated ANOVA measures, followed by a Tukey test (P<0,05. The results show that macrophyte increased until the seventh day of exposure in all treatments. After this period, the biomass of S. molesta decreased; but there was no significant difference between treatments with copper, except for the 8.0 mg L-1 treatment. The copper treatments decreased the S. molesta biomass an average of 43.2% (0.50 g DM after 28 days. At the end of the experiment, copper absorption in the treatments with 6.0 and 8.0 mg L-1 was on average 77.9% higher than in the treatments with 2 and 4 mg L-1 . The treatments with 6.0 and 8.0 mg L-1 reached their maximum bioaccumulation capacity after 14 days. The results show that contamination of the aquatic environment at concentrations above 2 mg L-1 Cu2+ can reduce the S. molesta biomass by approximately 43%.

  17. UV/草酸铁/H2O2法降解苯系物的研究%Degradation of BTX by UV/Ferrioxalate/H2O2 Process

    程丽华; 倪福祥



  18. Design of non-molecular coordination solids from aqueous solution: [CuIILnX(H2O)], where X=SO4, Cl or H2O and L=pyrazole, imidazole or glutamic acid and = 1 or 4

    Vineet Kumar; Aritra Kundu; Monika Singh; Kandalam V Ramanujachary; Arunachalam Rramanan


    We have successfully crystallized four new non-molecular coordination solids utilizing the synthons-Cu-OSO3- and -Cu-Cl- in the presence of four organic ligands:[{Cu()4SO4}{Cu()4SO4 (H2O)}]. H2O2, [Cu(imi)4SO4]3, [Cu(imi)4(NO3)2]4 and [Cu(glu)Cl(H2O)]5. Use of glutamic acid resulted in two chiral coordination polymers 5 and [Cu(glu)(H2O)]. H2O 6 depending on the copper source. The paper provides chemical insights to the supramolecular aggregation of a crystal driven by the various competing intermolecular forces.

  19. 三元体系NaBr-Na2SO4-H2O 和 NaBr-KBr-H2O 373 K相平衡%Phase Equilibria of Two Ternary Systems NaBr-Na2SO4-H2O and NaBr-KBr-H2O at 373 K

    桑世华; 崔瑞芝; 胡咏霞


    针对川西盆地富硼钾溴地下卤水组成,采用等温溶解平衡法研究了三元体系 NaBr-Na2SO4-H2O 和NaBr-KBr-H2O在373 K时的相平衡,测定了373 K条件下平衡溶液的溶解度和密度,根据实验数据绘制相应的相图和密度图。研究发现:两个三元体系在373 K条件下均属于简单共饱和型,无复盐及固溶体生成。相图中均有一个共饱和点,2个平衡固相结晶区和2条单变量曲线。在三元体系NaBr-Na2SO4-H2O中,平衡固相分别为:NaBr和Na2SO4,三元体系NaBr-KBr-H2O相应的平衡固相分别为:NaBr和KBr。并简单讨论了密度的变化规律。%Phase equilibria of two ternary systems NaBr-Na2SO4-H2O and NaBr-KBr-H2O at 373 K were studied by an isothermal solution saturation method. The solubility and density of these systems were determined experimentally and related phase diagrams were obtained. The results show that the two systems are both of simple type with no complex salts or solid solutions formed. Both of the phase diagrams show that they have one eutectic point, two univariant curves and two regions of crystallization. The solid phase in NaBr-Na2SO4-H2O is cpmposited of sodium bromide(NaBr) and sodium sulfate(Na2SO4), while sodium bromide(NaBr) and potassium bromide(KBr) are the components of the solid phase of NaBr-KBr-H2O. Density change of the two systems was discussed.

  20. Seasonal Mapping of [HDO]/[H2O] in the Martian Atmosphere

    Novak, Robert E.; Mumma, M. J.; Villanueva, G.; DiSanti, M. A.; Bonev, B.; Rahon, C. L.; Sanstead, C. C.


    We report seasonal changes in isotopic water on Mars, based on observations taken at NASA's IRTF using CSHELL. Column densities of HDO and H2O were extracted from individual spectral lines near 3.67 μm and 3.29 μm. The slit was positioned N-S on Mars' central meridian. Data were acquired in an ABBA sequence and their difference constitutes a spectral/spatial image from which each species was quantified. The frames were rectified by re-sampling in wavelength and spatial dimension, and spectra were then extracted at 0.6 arc-second intervals along the slit. We created atmospheric models for Earth and Mars using GENLN2 atmospheric software. The models include solar continuum (and Fraunhofer lines) with two-way transmission through Mars’ atmosphere, thermal emission from Mars’ surface and atmosphere with one-way transmission through Mars atmosphere, and one-way transmission through Earth's atmosphere for both. Latitudinal maps of [HDO]/[H2O] were constructed. The [HDO]/[H2O] ratios are always higher than terrestrial and they vary with both latitude and season. The ratio in the southern Martian hemisphere is found to be larger than that in the northern. This difference could be the signature of Rayleigh distillation, a process in which the different mean temperatures of the polar caps cause a different degree of HDO sequestration, resulting in different degrees of enrichment in the polar caps. For Ls =155o in 2003 and Ls =357o in 2006, HDO and H2O column densities were both obtained from CSHELL data. They will be compared with results from other seasons (Ls =67o in 1997, Ls =223o in 2005, and Ls =333o in 2004) when HDO was measured with CSHELL and H2O was measured by MGS-TES. This work was partially funded by grants from NASA's Planetary Astronomy Program (RTOP 344-32-51-96) and NSF RUI Program (AST-0505765). We acknowledge the NASA-IRTF for observing time and M. Smith for providing TES results.

  1. 基于UV/H2 O 2和UV/PS工艺降解水体中磺胺吡啶研究%Degradation of sulfapyridine in aqueous solution by UV/H2O2 and UV/PS technology

    何勇; 唐敏康; 卢丽娟; 庄珍珍; 高乃云


    采用高级氧化技术-紫外/双氧水(UV/H2 O2)和紫外/过硫酸盐(UV/PS)工艺降解磺胺吡啶(SPY)。研究表明,紫外与氧化剂(H2 O2、PS)联用可显著提高去除率,其反应符合拟一级动力学模型。目标污染物磺胺吡啶的去除率在一定浓度内随着氧化剂H2 O2和PS浓度升高而升高;磺胺吡啶初始浓度越大,反应速率越小;UV/H2 O2工艺降解磺胺吡啶最大去除率发生在pH=3,而UV/PS工艺降解SPY在pH=11时去除率最大;NaCl会抑制UV/H2 O2和UV/PS工艺对目标污染物的降解,而适当的NaHCO3可促进降解反应的进行;腐植酸对UV/PS工艺产生抑制作用,低浓度腐植酸(≤1 mmol/L)对UV/H2 O2工艺则有促进作用。%Using the advanced oxidation of technologies-ultraviolet/hydrogen peroxide and ultraviolet/per-sulfate technology degrade sulfapyridine.Research shows that it could improve the removal rate when adding oxidizers H2 O2 and PS,and degradation process conforme pseudo-first-order kinetics model.Within a certain concentration of oxidizers H2 O2 and PS,removal rate of target pollutant would improve when the oxidant concentration increasing.The reaction rate decreased with target pollutant’s initial concentration increasing.The maximum removal rate when UV/H2 O2 technology degradate sulfapyridine in the condi-tions pH=3 ,as for UV/PS technology,removal rate of degradating sulfapyridine becomes highest when pH=1 1 .NaCl has inhibiting effect on both UV/H2 O2 and UV/PS technology,but appropriate NaHCO3 has acceleration effect on it.Humic acids could produce inhibiting effect on UV/PS technology,but low concentration humic acids(≤1 mmol/L)has improve interaction for UV/H2 O2 technology.

  2. Radio continuum of galaxies with H2O megamaser disks: 33 GHz VLA data

    Kamali, F.; Henkel, C.; Brunthaler, A.; Impellizzeri, C. M. V.; Menten, K. M.; Braatz, J. A.; Greene, J. E.; Reid, M. J.; Condon, J. J.; Lo, K. Y.; Kuo, C. Y.; Litzinger, E.; Kadler, M.


    Context. Galaxies with H2O megamaser disks are active galaxies in whose edge-on accretion disks 22 GHz H2O maser emission has been detected. Because their geometry is known, they provide a unique view into the properties of active galactic nuclei. Aims: The goal of this work is to investigate the nuclear environment of galaxies with H2O maser disks and to relate the maser and host galaxy properties to those of the radio continuum emission of the galaxy. Methods: The 33 GHz (9 mm) radio continuum properties of 24 galaxies with reported 22 GHz H2O maser emission from their disks are studied in the context of the multiwavelength view of these sources. The 29-37 GHz Ka-band observations are made with the Karl Jansky Very Large Array in B, CnB, or BnA configurations, achieving a resolution of 0.2-0.5 arcsec. Hard X-ray data from the Swift/BAT survey and 22 μm infrared data from WISE, 22 GHz H2O maser data and 1.4 GHz data from NVSS and FIRST surveys are also included in the analysis. Results: Eighty-seven percent (21 out of 24) galaxies in our sample show 33 GHz radio continuum emission at levels of 4.5-240σ. Five sources show extended emission (deconvolved source size larger than 2.5 times the major axis of the beam), including one source with two main components and one with three main components. The remaining detected 16 sources (and also some of the above-mentioned targets) exhibit compact cores within the sensitivity limits. Little evidence is found for extended jets (>300 pc) in most sources. Either they do not exist, or our chosen frequency of 33 GHz is too high for a detection of these supposedly steep spectrum features. In NGC 4388, we find an extended jet-like feature that appears to be oriented perpendicular to the H2O megamaser disk. NGC 2273 is another candidate whose radio continuum source might be elongated perpendicular to the maser disk. Smaller 100-300 pc sized jets might also be present, as is suggested by the beam-deconvolved morphology of our

  3. Crystal Structure of Rare Earth Acrylates[Ln2(CH2 CHCOO)6·3H2O]·3H2O(Ln=Ce,Nd)%两种丙烯酸盐[Ln2(CH2CHCOO)6·3H2O]·3H2O(Ln=Ce;Nd)的单晶结构

    钱玉英; 褚晓东; 姚有为


    Crystal strudures of [Ln2 (CH2CHCOO)6·3H2O](Ln = Ce,Nd) were characterized by using X - ray single crystal analysis. The title compounds are iso - structural: monoclime system, apace group P21/c with a= 1.02099 (13)nm,b = 1.52294(19) nm,c = 2.0325(3) nm,β= 100.838 (2)°, V = 3.1039 (7) nm3 for [ Ce2 ( CH2CHCOO) 6·3H2O] ;α=1.01978(8) nm, b=1.50979 (12) nm, c=2.02712 (16) nm,β=100.881 (1)°, V = 3.0650 (4) nm3 for [ND2 (CH2CHCOO)6·3H2O]. There are two independent Ln ions in the asymmetric unit, which are located in nona - coor-dinated and deca - coordinated environments respectively. The two Ln ions are bridged togetber by two μ2 - oxygen atoms of two independent acrylates, resulting in left - handed and right - handed helical chains. Hydrogen network are built up from helical chains and water molecules located between two neighbor chains. giying rise to three - dimensional stack.%采用X射线单晶衍射法,解析了[Ln2(CH:CHCOO)6·3H2O]·3H2O(Ln=Ce;Nd)的结构.结果表明标题化合物属同构:属单斜晶系(空间群P2(1)/c);[Ce2(CH2CHCOO)6·3H2O]·3H2O晶胞参数α=1.02099(13)nm,b=1.52294(19)nm,c=2.0325(3)nin,/3=100.838(2)°,V=3.1039(7)nm3;[Nd2(CH2CHCOO)6·3H2O]·3H2O晶胞参数α=1.01978(8)nm,6=1.50979(12)nm,c=2.02712(16)nm,β=100.881(1)°,V=3.0650(4)nm3.化合物不对称结构单元中含有两个独立的稀土中心离子,分别处九、十配位环境中.两个稀土离子由两个独立的丙烯酸μ2-氧桥联形成左手和右手螺旋链.螺旋链通过链间的水分子形成氢键网络,堆垛成三维结构.

  4. Enhancement of photoelectric response of bacteriorhodopsin by multilayered WO3 x H2O nanocrystals/PVA membrane.

    Li, Rui; Hu, Fengping; Bao, Qiaoliang; Bao, Shujuan; Qiao, Yan; Yu, Shucong; Guo, Jun; Li, Chang Ming


    For the first time, a multilayered WO(3) x H(2)O/PVA membrane on bacteriorhodopsin (bR) is constructed to significantly enhance the photoelectric response of bR by the spillover effect of WO(3) x H(2)O nanocrystals, providing great potential in its important applications in bioelectronics and proton exchange membrane fuel cells.

  5. Inhibition of PKR protects against H2O2-induced injury on neonatal cardiac myocytes by attenuating apoptosis and inflammation

    Wang, Yongyi; Men, Min; Xie, Bo; Shan, Jianggui; Wang, Chengxi; Liu, Jidong; Zheng, Hui; Yang, Wengang; Xue, Song; Guo, Changfa


    Reactive oxygenation species (ROS) generated from reperfusion results in cardiac injury through apoptosis and inflammation, while PKR has the ability to promote apoptosis and inflammation. The aim of the study was to investigate whether PKR is involved in hydrogen peroxide (H2O2) induced neonatal cardiac myocytes (NCM) injury. In our study, NCM, when exposed to H2O2, resulted in persistent activation of PKR due to NCM endogenous RNA. Inhibition of PKR by 2-aminopurine (2-AP) or siRNA protected against H2O2 induced apoptosis and injury. To elucidate the mechanism, we revealed that inhibition of PKR alleviated H2O2 induced apoptosis companied by decreased caspase3/7 activity, BAX and caspase-3 expression. We also revealed that inhibition of PKR suppressed H2O2 induced NFκB pathway and NLRP3 activation. Finally, we found ADAR1 mRNA and protein expression were both induced after H2O2 treatment through STAT-2 dependent pathway. By gain and loss of ADAR1 expression, we confirmed ADAR1 modulated PKR activity. Therefore, we concluded inhibition of PKR protected against H2O2-induced injury by attenuating apoptosis and inflammation. A self-preservation mechanism existed in NCM that ADAR1 expression is induced by H2O2 to limit PKR activation simultaneously. These findings identify a novel role for PKR/ADAR1 in myocardial reperfusion injury. PMID:27929137

  6. Kinetics and efficiency of H2O2 activation by iron-containing minerals and aquifer materials.

    Pham, Anh Le-Tuan; Doyle, Fiona M; Sedlak, David L


    To gain insight into factors that control H(2)O(2) persistence and ·OH yield in H(2)O(2)-based in situ chemical oxidation systems, the decomposition of H(2)O(2) and transformation of phenol were investigated in the presence of iron-containing minerals and aquifer materials. Under conditions expected during remediation of soil and groundwater, the stoichiometric efficiency, defined as the amount of phenol transformed per mole of H(2)O(2) decomposed, varied from 0.005 to 0.28%. Among the iron-containing minerals, iron oxides were 2-10 times less efficient in transforming phenol than iron-containing clays and synthetic iron-containing catalysts. In both iron-containing mineral and aquifer materials systems, the stoichiometric efficiency was inversely correlated with the rate of H(2)O(2) decomposition. In aquifer materials systems, the stoichiometric efficiency was also inversely correlated with the Mn content, consistent with the fact that the decomposition of H(2)O(2) on manganese oxides does not produce ·OH. Removal of iron and manganese oxide coatings from the surface of aquifer materials by extraction with citrate-bicarbonate-dithionite slowed the rate of H(2)O(2) decomposition on aquifer materials and increased the stoichiometric efficiency. In addition, the presence of 2 mM of dissolved SiO(2) slowed the rate of H(2)O(2) decomposition on aquifer materials by over 80% without affecting the stoichiometric efficiency.

  7. Herschel observations of ortho- and para-oxidaniumyl (H2O+) in spiral arm clouds toward Sagittarius B2(M)

    Schilke, P.; Comito, C.; Müller, H. S. P.; Bergin, E. A.; Herbst, E.; Lis, D. C.; Neufeld, D. A.; Phillips, T. G.; Bell, T. A.; Blake, G. A.; Cabrit, S.; Caux, E.; Ceccarelli, C.; Cernicharo, J.; Crockett, N. R.; Daniel, F.; Dubernet, M.-L.; Emprechtinger, M.; Encrenaz, P.; Falgarone, E.; Gerin, M.; Giesen, T. F.; Goicoechea, J. R.; Goldsmith, P. F.; Gupta, H.; Joblin, C.; Johnstone, D.; Langer, W. D.; Latter, W. B.; Lord, S. D.; Maret, S.; Martin, P. G.; Melnick, G. J.; Menten, K. M.; Morris, P.; Murphy, J. A.; Ossenkopf, V.; Pagani, L.; Pearson, J. C.; Pérault, M.; Plume, R.; Qin, S.-L.; Salez, M.; Schlemmer, S.; Stutzki, J.; Trappe, N.; van der Tak, F. F. S.; Vastel, C.; Wang, S.; Yorke, H. W.; Yu, S.; Erickson, N.; Maiwald, F. W.; Kooi, J.; Karpov, A.; Zmuidzinas, J.; Boogert, A.; Schieder, R.; Zaal, P.


    H2O+ has been observed in its ortho- and para- states toward the massive star forming core Sgr B2(M), located close to the Galactic center. The observations show absorption in all spiral arm clouds between the Sun and Sgr B2. The average o/p ratio of H2O+ in most velocity intervals is 4.8, which cor

  8. Absolute Infrared Cross Sections of Gas-Phase H2O2 Using Fourier Transform Mid-Infrared Spectroscopy

    Johnson, Timothy J.; Blake, Thomas A.; Sams, Robert L.; Burton, Sarah D.


    We report quantitative spectra of pressure-broadened H2O2 vapor. An 83% solution was flowed into a disseminator and diluted with N2 gas; water lines were subtracted. The H2O2 spectrum spans the IR and compares well with HITRAN values for ν6 band.

  9. Herschel observations of ortho- and para-oxidaniumyl (H2O+) in spiral arm clouds toward Sagittarius B2(M)

    Schilke, P.; Comito, C.; Mueller, H. S. P.; Bergin, E. A.; Herbst, E.; Lis, D. C.; Neufeld, D. A.; Phillips, T. G.; Bell, T. A.; Blake, G. A.; Cabrit, S.; Caux, E.; Ceccarelli, C.; Cernicharo, J.; Crockett, N. R.; Daniel, F.; Dubernet, M. -L.; Emprechtinger, M.; Encrenaz, P.; Falgarone, E.; Gerin, M.; Giesen, T. F.; Goicoechea, J. R.; Goldsmith, P. F.; Gupta, H.; Joblin, C.; Johnstone, D.; Langer, W. D.; Latter, W. B.; Lord, S. D.; Maret, S.; Martin, P. G.; Melnick, G. J.; Menten, K. M.; Morris, P.; Murphy, J. A.; Ossenkopf, Volker; Pagani, L.; Pearson, J. C.; Perault, M.; Plume, R.; Qin, S. -L.; Salez, M.; Schlemmer, S.; Stutzki, J.; Trappe, N.; van der Tak, F. F. S.; Vastel, C.; Wang, S.; Yorke, H. W.; Yu, S.; Erickson, N.; Maiwald, F. W.; Kooi, J.; Karpov, A.; Zmuidzinas, J.; Boogert, A.; Schieder, R.; Zaal, P.


    H2O+ has been observed in its ortho- and para- states toward the massive star forming core Sgr B2(M), located close to the Galactic center. The observations show absorption in all spiral arm clouds between the Sun and Sgr B2. The average o/p ratio of H2O+ in most velocity intervals is 4.8, which

  10. Flow cytometric analysis of the H2O2-induced increase in intracellular Ca2+ concentration of rat thymocytes.

    Okazaki, E; Chikahisa, L; Kanemaru, K; Oyama, Y


    The effect of hydrogen peroxide (H2O2) on the intracellular Ca2+ concentration ([Ca2+]i) of rat thymocytes was examined by a flow cytometer and two fluorescent dyes, fluo-3-AM and ethidium bromide, a dye impermeant to intact membranes, to characterize the H2O2-induced increase in [Ca2+]i. H2O2 at concentrations greater than 30 microM dose-dependently increased the [Ca2+]i of thymocytes which were not stained with ethidium. Removal of external Ca2+ greatly reduced the degree of H2O2-induced increase in [Ca2+]i. However, H2O2 still increased the [Ca2+]i under the external Ca(2+)-free condition. Diethylmaleate, which is known to produce a chemical depletion of cellular nonprotein thiol, significantly increased the [Ca2+]i. Dithiothreitol, which is used to protect cellular nonprotein thiol, slightly decreased the [Ca2+]i, but greatly reduced the H2O2-induced increase in [Ca2+]i. Therefore, it is considered that H2O2 may increase the [Ca2+]i through a mechanism related to the effects of H2O2 on the cellular nonprotein thiol.

  11. Infrared characteristics of sources associated with OH, H2O, SiO and CH3OH masers

    Esimbek, Jarken; Wu, Gang; Di Tang, Xin


    We collect all published OH, H2O, SiO and CH3OH masers in literature. The as-sociated infrared sources of these four masers were identi?ed with MSX PSC catalogues. We look for common infrared properties among the sources associated with four masers and make a statistical study. The MSX sources associated with stellar OH, stellar H2O and SiO masers concentrated in a small regions and the MSX sources associated with interstellar OH, interstellar H2O and CH3OH masers also concentrated in a small regions in an [A]-[D].vs.[A][-[E] diagram. These results give us new criterion to search for coexisting stellar maser samples for OH, H2O and SiO masers and interstellar maser samples for OH, H2O and CH3OH masers.

  12. Communication: Quantum six-dimensional calculations of the coupled translation-rotation eigenstates of H2O@C60

    Felker, Peter M.; Bačić, Zlatko


    We report rigorous quantum calculations of the translation-rotation (TR) eigenstates of para- and ortho-H2O@C60. They provide a comprehensive description of the dynamical behavior of H2O inside the fullerene having icosahedral (Ih) symmetry. The TR eigenstates are assigned in terms of the irreducible representations of the proper symmetry group of H2O@C60, as well as the appropriate translational and rotational quantum numbers. The coupling between the orbital and the rotational angular momenta of the caged H2O gives rise to the total angular momentum λ, which additionally labels each TR level. The calculated TR levels allow tentative assignments of a number of transitions in the recent experimental INS spectra of H2O@C60 that have not been assigned previously.

  13. Synthesis and Thermodynamic Properties of MgO·B2O3·4H2O

    LIU,Zhi-Hong(刘志宏); GAO,Shi-Yang(高世扬); HU,Man-Cheng(胡满成); XIA,Shu-Ping(夏树屏)


    A new magnesium borate MgO@ B2O3 @ 4H2O was synthesized by the method of phase transformation of double salt and characterized by XRD, IR spectra and TG. The structural formula of this compound was Mg[B2O(OH)6] @H2O. The enthalpy of solution of MgO@B2O3@4H2O in HCl (1.0492 mol@ L-1) was determined. With the incorporation of the standard molar enthalpies of formation of MgO (s), H3BO3(s), and H2O (Ⅰ),the standard molar enthalpy of formation of - (3135.31 ±1.68) kJ@ mol-1 of MgO@B2O3@4H2O was obtained. Thermodynamic properties of this compoumd were also calculated by group contribution method.

  14. Invited: Tailoring Platinum Group Metals Towards Optimal Activity for Oxygen Electroreduction to H2o and H2O2: From Extended Surfaces to Nanoparticles

    Stephens, Ifan


    demonstrated the very high activity of Pt3Y and Pt5Gd on extended polycrystalline surfaces. However, we have more recently shown that model, size-selected nanoparticles of PtxY exhibit up to 3 Ag-1at 0.9 V. These promising results provide a strong impetus towards the large scale synthesis of these catalysts...... a catalyst that is active, stable and selective for H2O2 production. We recently discovered a set of electrocatalysts that showed an unprecedented combination of all three of these desired properties: alloys of Pt, Ag or Pd with Hg.(10, 11) I will present data collected a wide range of different methods...... ). The figure shows transmission electron miscroscopy images of 9 nm diameter PtxY nanoparticles, based on high angle annular dark field –scanning transmission electron microscopy (left) and Y, Pt and combined Pt+Y X-ray energy dispersive X-ray spectroscopy elemental maps. (a) as-prepared catalyst and (b) after...

  15. Synthesis, characterization and electrochemical performance of graphene decorated with 1D NiMoO4.nH2O nanorods

    Ghosh, Debasis; Giri, Soumen; Das, Chapal Kumar


    One-dimensional NiMoO4.nH2O nanorods and their graphene based hybrid composite with good electrochemical properties have been synthesized by a cost effective hydrothermal procedure. The formation of the mixed metal oxide and the composite was confirmed by XRD, XPS and Raman analyses. The morphological characterizations were carried out using FESEM and TEM analyses. The materials were subjected to electrochemical characterization through cyclic voltammetry (CV), galvanostatic charge-discharge (GCD) and electrochemical impedance spectroscopy (EIS) studies with 6 M KOH as the supporting electrolyte. For NiMoO4.nH2O, a maximum specific capacitance of 161 F g-1 was obtained at 5 A g-1 current density, accompanied with an energy density of 4.53 W h kg-1 at a steady power delivery rate of 1125 W kg-1. The high utility of the pseudocapacitive NiMoO4.nH2O was achieved in its graphene based composite, which exhibited a high specific capacitance of 367 F g-1 at 5 A g-1 current density and a high energy density of 10.32 W h kg-1 at a power density of 1125 W kg-1 accompanied with long term cyclic stability.One-dimensional NiMoO4.nH2O nanorods and their graphene based hybrid composite with good electrochemical properties have been synthesized by a cost effective hydrothermal procedure. The formation of the mixed metal oxide and the composite was confirmed by XRD, XPS and Raman analyses. The morphological characterizations were carried out using FESEM and TEM analyses. The materials were subjected to electrochemical characterization through cyclic voltammetry (CV), galvanostatic charge-discharge (GCD) and electrochemical impedance spectroscopy (EIS) studies with 6 M KOH as the supporting electrolyte. For NiMoO4.nH2O, a maximum specific capacitance of 161 F g-1 was obtained at 5 A g-1 current density, accompanied with an energy density of 4.53 W h kg-1 at a steady power delivery rate of 1125 W kg-1. The high utility of the pseudocapacitive NiMoO4.nH2O was achieved in its graphene

  16. Compromised Photosynthetic Electron Flow and H2O2 Generation Correlate with Genotype-Specific Stomatal Dysfunctions during Resistance against Powdery Mildew in Oats.

    Sánchez-Martín, Javier; Montilla-Bascón, Gracia; Mur, Luis A J; Rubiales, Diego; Prats, Elena


    Stomatal dysfunction known as "locking" has been linked to the elicitation of a hypersensitive response (HR) following attack of fungal pathogens in cereals. We here assess how spatial and temporal patterns of different resistance mechanisms, such as HR and penetration resistance influence stomatal and photosynthetic parameters in oat (Avena sativa) and the possible involvement of hydrogen peroxide (H2O2) in the dysfunctions observed. Four oat cultivars with differential resistance responses (i.e., penetration resistance, early and late HR) to powdery mildew (Blumeria graminis f. sp. avenae, Bga) were used. Results demonstrated that stomatal dysfunctions were genotype but not response-type dependent since genotypes with similar resistance responses when assessed histologically showed very different locking patterns. Maximum quantum yield (Fv/Fm) of photosystem II were compromised in most Bga-oat interactions and photoinhibition increased. However, the extent of the photosynthetic alterations was not directly related to the extent of HR. H2O2 generation is triggered during the execution of resistance responses and can influence stomatal function. Artificially increasing H2O2 by exposing plants to increased light intensity further reduced Fv/Fm ratios and augmented the patterns of stomatal dysfunctions previously observed. The latter results suggest that the observed dysfunctions and hence a cost of resistance may be linked with oxidative stress occurring during defense induced photosynthetic disruption.

  17. Degradation of antidepressant drug fluoxetine in aqueous media by ozone/H2O2 system: process optimization using central composite design.

    Aghaeinejad-Meybodi, Abbas; Ebadi, Amanollah; Shafiei, Sirous; Khataee, Alireza; Rostampour, Mohammad


    The main objective of this work is the modelling and optimization of antidepressant drug fluoxetine degradation in aqueous solution by ozone/H2O2 process using central composite design. The operational parameters were ozone concentration, initial hydrogen peroxide concentration, reaction time and initial fluoxetine concentration. A good agreement between the predicted values of fluoxetine removal and experimental results were observed (R2=0.976 and Adj-R2=0.955). Pareto analysis indicated that all selected factors and some interactions were effective on the removal efficiency. It was found that the reaction time is the most effective parameter in the ozone/H2O2 process. The maximum removal efficiency (86.14%) was achieved at ozone concentration of 30 mg L(-1), initial H2O2 concentration of 0.02 mM, reaction time of 20 min and initial fluoxetine concentration of 50 mg L(-1) as the optimum conditions.

  18. Removal of petroleum hydrocarbons from contaminated groundwater by the combined technique of adsorption onto perlite followed by the O3/H2O2 process.

    Moussavi, Gholamreza; Bagheri, Amir


    Groundwater contaminated with petroleum hydrocarbons was treated using a combined system of adsorption onto powdered expanded perlite (PEP) followed by the O3/H2O2 process. The pretreatment investigations indicated a high capacity for PEP to remove petroleum hydrocarbons from the contaminated water. An experimental total petroleum hydrocarbon (TPH) adsorption capacity of 275 mg/g PEP was obtained at the natural pH of water. The experimental data fit best with the Freundlich isotherm model and pseudo-second-order adsorption model. The second phase of the experiment evaluated the performance of the O3/H2O2 process in the removal of residual TPH from pretreated water and compared the results with that of raw water. The O3/H202 process attained a maximum TPH removal rate for the pretreated water after 70 min, when 93% of the residual TPH in the effluent of the adsorption system was removed. Overall, the combination of adsorption onto PEP for 100 min and the subsequent treatment with the O3/H2O2 process for 70min eliminated over 99% of the TPH of highly petroleum-contaminated groundwater, with initial values of 162 mg/L. Therefore, we can conclude that the developed treatment system is an appropriate method of remediation for petroleum-contaminated waters.

  19. Enhanced poly(γ-glutamic acid) production by H2 O2 -induced reactive oxygen species in the fermentation of Bacillus subtilis NX-2.

    Tang, Bao; Zhang, Dan; Li, Sha; Xu, Zongqi; Feng, Xiaohai; Xu, Hong


    Effects of reactive oxygen species (ROS) on cell growth and poly(γ-glutamic acid) (γ-PGA) synthesis were studied by adding hydrogen peroxide to a medium of Bacillus subtilis NX-2. After optimizing the addition concentration and time of H2 O2 , a maximum concentration of 33.9 g/L γ-PGA was obtained by adding 100 µM H2 O2 to the medium after 24 H. This concentration was 20.6% higher than that of the control. The addition of diphenyleneiodonium chloride (ROS inhibitor) can interdict the effect of H2 O2 -induced ROS. Transcriptional levels of the cofactors and relevant genes were also determined under ROS stress to illustrate the possible metabolic mechanism contributing to the improve γ-PGA production. The transcriptional levels of genes belonging to the tricarboxylic acid cycle and electron transfer chain system were significantly increased by ROS, which decreased the NADH/NAD(+) ratio and increased the ATP levels, thereby providing more reducing power and energy for γ-PGA biosynthesis. The enhanced γ-PGA synthetic genes also directly promoted the formation of γ-PGA. This study was the first to use the ROS control strategy for γ-PGA fermentation and provided valuable information on the possible mechanism by which ROS regulated γ-PGA biosynthesis in B. subtilis NX-2.

  20. Kinetics Research of UV/H2O2 Combination Method in PAEs Degradation%UV/H2O2联用技术降解水中PAEs的动力学研究



    针对水体中较高含量的邻苯二甲酸酯(PAEs)污染,采用UV/H2O2联用技术降解PAEs,考察H2O2浓度、PAEs初始浓度及反应体系中pH等因素对PAEs降解效果的影响.结果表明:UV/H2O2对DMP、DEP的处理效果要优于UV、H2O2单一处理.且PAEs的降解效率随反应体系中H2O2浓度增大而升高,随着PAEs初始浓度的增加而降低,不同pH对于光降解PAEs产生的影响不大.在优化实验条件下,采用UV/H2O2降解DMP、DEP,当PAEs初始浓度为5 mg/L、H2O2投加量为330 mg/L时,DMP和DEP的降解率可分别达到80.7%和84%.

  1. Incorporation of M(H2O)6(2+) between layers {M(H2O)2Ru2(CO3)4Cl2}n(2n-) (M = Zn, Mn): syntheses, structures and magnetic properties.

    Liu, Bin; Jia, Yan-Yan; Yang, Huai-Qing; Yang, Jian-Hui; Xue, Gang-Lin


    Isostructural heterometallic diruthenium carbonates KM(H2O)6[M(H2O)2Ru2(CO3)4Cl2]·4H2O [M = Zn (1) and Mn (2)] were synthesized from the reaction of the precursors [Ru2(CO3)4Cl2](5-) and transitional metal ions in aqueous solution. Complexes 1 and 2 show layered structures in which Ru2(II,III) units are linked by four octahedral environment M(H2O)2(2+) ions in a cross fashion and vice versa giving a negative bimetallic square grid layer {M(H2O)2Ru2(CO3)4Cl2}n(3n-). M(H2O)6(2+) ions, linked by K(+) forming zigzag chain {KM(H2O)6}n(3+), are located in the void spaces between the layers. The adjacent bimetallic carbonate layers are connected with K-O and K-Cl bonds, and hydrogen bonding, forming a supramolecular 3D framework structure. Their magnetic properties were characterized in detail, and intralayer ferromagnetic coupling between the Ru2 dimer and Mn(2+) ion, as well as long-range ordering (Tc = 5.2 K) coexistence of domain movement behavior were observed for complex 2.

  2. H2O2-mediated DNA damage and repair in the brain cells in the aging rats detected by comet assay

    Suming ZhangM.D., Ph.D; Zongchao Han, M.D.; Siyu Fang, M.D.; Ruan Yang, M.D; Wei Wang, M.D., Ph. D


    Objective: To identify the relation between DNA damage susceptibility/ DNA repair capability and aging process after insults, an observation of H2O2_induced DNA damage and the kinetics of DNA repair in senescent murine brain cells with the alkaline single cell gel electrophoresis (SCGE/Comet assay) was made. Methods: The dissociated brain cells harvested in the area of the cerebral cortex, hippocampus, basal gang]ion from 3-month (n=10), 8-month (n=8) and 26-month (n=5) old rats were respectively treated with H2O2 in gradient doses for 10 min, or without H2O2 as controls. The cells embedded in agarose were lysed, helix-untied, electrophoresed, stained with a fluorescence DNA binding stain, viewed under a fluorescence microscope. Individual image was optically recorded. The frequency of the tailed cells and the grade of tails wereused to analyze single strand breaks of DNA and injury intensity. Results: By the cell and DNA image like comets, a linear increase was noticed in vulnerability of DNA both to H2O2 doses and to the age. Regarding the damaged region of the brain, the cortex cells were more vulnerable to the insult than the hippocampus/basal ganglionic cells. Whatever aging or not the cells were, the maximum of ratio of DNA repair was only within 1 hour during the incubation for 0.5-4 hours after the insults. Furthermore, the more aging, the less ratio of DNA repair of sick cells. Conclusion: The DNA damagesusceptibility and the DNA repair capability of individual cells, whatever its age is, can be detected by this brain cell injury model. Comet assay is a sensitive way to find out DNA damage and repair of the cells. It should be more difficult for the cells to cope with an acute and excessive than with a persistent, chronic and mild DNA damage which is more related to an accumulating injury, the aging.

  3. H2O and CO2 exchange between a sphagnum mire ecosystem and the atmosphere

    Olchev, Alexander; Volkova, Elena; Karataeva, Tatiana; Novenko, Elena


    The modern climatic conditions are strongly influenced by both internal variability of climatic system, and various external natural and anthropogenic factors (IPCC 2007). Significant increase of concentration of greenhouse gases in the atmosphere and especially the growth of atmospheric CO2 due to human activity are considered as the main factors that are responsible for modern global warming and climate changes. A significant part of anthropogenic CO2 is absorbed from the atmosphere by land biota and especially by vegetation cover. However, it is still not completely clear what is the role of different land ecosystems and especially forests and mires in global cycles of H2O and CO2 and what is a sensitivity of these ecosystems to climate changes. Within the framework of this study the spatial and temporal variability of H2O and CO2 fluxes between a mire ecosystem and the atmosphere was described using results of the field measurements and modeling approach. For the study a mire ecosystem located in Tula region in European part of Russia was selected. The selected mire has karst origin, depth of peat float is 2.5-3.0 m (depth of depression is more than 10 meter), area is about 1 ha. The mire vegetation is characterized by sedge and sphagnum mosses cover. The mire is surrounded by broad-leaved forest of about 20 meter high. To describe the temporal and spatial patterns of H2O and CO2 fluxes within selected mire the chamber method was applied. The measurement were carried out along transect from mire edge to center from June to September of 2012. For measurements the transparent ventilated chambers combined with portable infrared CO2/H2O analyzer LI-840 (Li-Cor, USA) was used. To estimate the gross primary production and respiration of different type of vegetation within the mire the measurements were conducted both under actual light conditions and artificial shading. Results of the experimental studies showed that the maximal CO2 fluxes was observed in central

  4. Modeling approaches to describe H2O and CO2 exchange in mare ecosystems

    Olchev, A.; Novenko, E.; Volkova, E.


    The modern climatic conditions is strongly influenced by both internal variability of climatic system, and various external natural and anthropogenic factors (IPCC 2007). Significant increase of concentration of greenhouse gases in the atmosphere and especially the growth of atmospheric CO2 due to human activity are considered as the main factors that are responsible for global warming and climate changes. A significant part of anthropogenic CO2 is absorbed from the atmosphere by land biota and especially by vegetation cover. However, it is still not completely clear what is the role of different land ecosystems and especially forests and mares in global cycles of H2O and CO2 and what is a sensitivity of these ecosystems to climate changes. Within the frameworks of this study the spatial and temporal variability of H2O and CO2 fluxes in different types of mare ecosystems of the forest-steppe zone in European part of Russia was described using modeling approaches and results of field measurements. For this modeling and experimental study the mare ecosystems of Tula region were selected. The Tula region is located mostly in the forest-steppe zone and it is unique area for such studies because almost all existed types of mare ecosystems of Northern Eurasia distinguished by a geomorphological position, water and mineral supply can be found there. Most mares in Tula region have a relatively small size and surrounded by very heterogeneous forests that make not possible an application of the classical measuring and modeling approaches e.g. an eddy covariance technique or one-dimensional H2O and CO2 exchange models for flux estimation in such sites. In our study to describe the radiation, sensible heat, H2O and CO2 exchange between such heterogeneous mare ecosystems and the atmosphere a three-dimensional model Forbog-3D and one-dimensional Mixfor-SVAT were applied. The main concept used in the Forbog-3D and Mixfor-SVAT models is an aggregated description of physical and

  5. Solubility of water in lunar basalt at low pH2O

    Newcombe, M. E.; Brett, A.; Beckett, J. R.; Baker, M. B.; Newman, S.; Guan, Y.; Eiler, J. M.; Stolper, E. M.


    We report the solubility of water in Apollo 15 basaltic "Yellow Glass" and an iron-free basaltic analog composition at 1 atm and 1350 °C. We equilibrated melts in a 1-atm furnace with flowing H2/CO2 gas mixtures that spanned ∼8 orders of magnitude in fO2 (from three orders of magnitude more reducing than the iron-wüstite buffer, IW-3.0, to IW+4.8) and ∼4 orders of magnitude in pH2/pH2O (from 0.003 to 24). Based on Fourier transform infrared spectroscopy (FTIR), our quenched experimental glasses contain 69-425 ppm total water (by weight). Our results demonstrate that under the conditions of our experiments: (1) hydroxyl is the only H-bearing species detected by FTIR; (2) the solubility of water is proportional to the square root of pH2O in the furnace atmosphere and is independent of fO2 and pH2/pH2O; (3) the solubility of water is very similar in both melt compositions; (4) the concentration of H2 in our iron-free experiments is ppm, even at oxygen fugacities as low as IW-2.3 and pH2/pH2O as high as 11; (5) Secondary ion mass spectrometry (SIMS) analyses of water in iron-rich glasses equilibrated under variable fO2 conditions may be strongly influenced by matrix effects, even when the concentration of water in the glasses is low; and (6) Our results can be used to constrain the entrapment pressure of lunar melt inclusions and the partial pressures of water and molecular hydrogen in the carrier gas of the lunar pyroclastic glass beads. We find that the most water-rich melt inclusion of Hauri et al. (2011) would be in equilibrium with a vapor with pH2O ∼ 3 bar and pH2 ∼ 8 bar. We constrain the partial pressures of water and molecular hydrogen in the carrier gas of the lunar pyroclastic glass beads to be 0.0005 bar and 0.0011 bar respectively. We calculate that batch degassing of lunar magmas containing initial volatile contents of 1200 ppm H2O (dissolved primarily as hydroxyl) and 4-64 ppm C would produce enough vapor to reach the critical vapor volume

  6. Degradation of 5-FU by means of advanced (photo)oxidation processes: UV/H2O2, UV/Fe2+/H2O2 and UV/TiO2--Comparison of transformation products, ready biodegradability and toxicity.

    Lutterbeck, Carlos Alexandre; Wilde, Marcelo Luís; Baginska, Ewelina; Leder, Christoph; Machado, Ênio Leandro; Kümmerer, Klaus


    The present study investigates the degradation of the antimetabolite 5-fluorouracil (5-FU) by three different advanced photo oxidation processes: UV/H2O2, UV/Fe(2+)/H2O2 and UV/TiO2. Prescreening experiments varying the H2O2 and TiO2 concentrations were performed in order to set the best catalyst concentrations in the UV/H2O2 and UV/TiO2 experiments, whereas the UV/Fe(2+)/H2O2 process was optimized varying the pH, Fe(2+) and H2O2 concentrations by means of the Box-Behnken design (BBD). 5-FU was quickly removed in all the irradiation experiments. The UV/Fe(2+)/H2O2 and UV/TiO2 processes achieved the highest degree of mineralization, whereas the lowest one resulted from the UV/H2O2 treatment. Six transformation products were formed during the advanced (photo)oxidation processes and identified using low and high resolution mass spectrometry. Most of them were formed and further eliminated during the reactions. The parent compound of 5-FU was not biodegraded, whereas the photolytic mixture formed in the UV/H2O2 treatment after 256 min showed a noticeable improvement of the biodegradability in the closed bottle test (CBT) and was nontoxic towards Vibrio fischeri. In silico predictions showed positive alerts for mutagenic and genotoxic effects of 5-FU. In contrast, several of the transformation products (TPs) generated along the processes did not provide indications for mutagenic or genotoxic activity. One exception was TP with m/z 146 with positive alerts in several models of bacterial mutagenicity which could demand further experimental testing. Results demonstrate that advanced treatment can eliminate parent compounds and its toxicity. However, transformation products formed can still be toxic. Therefore toxicity screening after advanced treatment is recommendable.

  7. Degradation of dye effluents with UV/H2 O2/ferric ammonium oxalate system%UV/H2O2/草酸高铁铵对甲苯胺蓝的降解作用

    张昕; 塔娜


    研究采用UV、H2O2、草酸高铁铵体系处理甲苯胺蓝(Toluidine blue,简称为TB)溶液的降解作用.考察了TB初始浓度、初始pH值、H2O2浓度、草酸高铁铵浓度对TB降解率的影响.试验结果表明,酸性条件有利于TB的降解,其最佳降解pH值为4.0.在UV/H2O2体系中,H2O2浓度在100 mmoL/L时,TB降解率相对高;UV/草酸高铁铵体系中,草酸高铁铵浓度为10.0 mmol/L时TB降解率较高;相比于其它体系,UV/H2O2/草酸高铁铵体系的降解效果最好,降解率可达88.62%.%The influences of initial concentration of TB, initial pH value and dosages of H2O2 and amrnonium ferric oxalate on degradation of TB are investigated.The results show that acidic condition tends to promote the degradation of TB , especially at pH value of 4.0.In UV/H2 O2 system and UV/ammonium ferric oxalate system , the degradation of TB is relative higher with the concentration of H2O2 100 mmol/L and ammonium ferric oxalate 10.0 mmol/L respectively.Compared to other systems,UV/H2O2/ammonium ferric oxalate system show the highest degradation rate of TB with 88.62 % .

  8. Aging of LiFePO 4 upon exposure to H 2O

    Zaghib, K.; Dontigny, M.; Charest, P.; Labrecque, J. F.; Guerfi, A.; Kopec, M.; Mauger, A.; Gendron, F.; Julien, C. M.

    The effect of H 2O on carbon-coated LiFePO 4 particles was investigated by chemical analysis, structural analysis (X-ray diffraction, SEM, TEM), optical spectroscopy (FTIR, Raman) and magnetic measurements. Upon immersion in water, part of the product floats while the main part sinks. Both the floating and the sinking part have been analyzed. We find that the floating and sinking part only differ by the amount of carbon that partly detaches from the particles upon immersion in water. Exposure to H 2O results in rapid attack, within minutes, of the surface layer of the particles, because the particles are no longer protected by carbon. The deterioration of the carbon coat is dependent on the synthesis process, either hydrothermal or solid-state reaction. In both cases, however, the carbon coat is permeable to water and fails to protect the surface of the LiFePO 4 particles. The consequence is that this immersion results in the chemical attack of LiFePO 4, but is restricted to the surface layer of the particles (few nanometers-thick). In case the particles are simply exposed to humid air, the carbon coat protects the particles more efficiently. In this case, the exposure to H 2O mainly results in the delithiation of the surface layer, due to the hydrophilic nature of Li, and only the surface layer is affected, at least for a reasonable time of exposure to humid air (weeks). In addition, within this timescale, the surface layer can be chemically lithiated again, and the samples can be dried to remove the moisture, restoring the reversible electrochemical properties.

  9. New near-IR observations of mesospheric CO2 and H2O clouds on Mars

    Vincendon, Mathieu; Pilorget, Cedric; Gondet, Brigitte; Murchie, Scott; Bibring, Jean-Pierre


    Carbon dioxide clouds, which are speculated by models on solar and extra-solar planets, have been recently observed near the equator of Mars. The most comprehensive identification of Martian CO2 ice clouds has been obtained by the near-IR imaging spectrometer OMEGA. CRISM, a similar instrument with a higher spatial resolution, cannot detect these clouds with the same method due to its shorter wavelength range. Here we present a new method to detect CO2 clouds using near-IR data based on the comparison of H2O and CO2 ice spectral properties. The spatial and seasonal distributions of 54 CRISM observations containing CO2 clouds are reported, in addition to 17 new OMEGA observations. CRISM CO2 clouds are characterized by grain size in the 0.5-2 μm range and optical depths lower than 0.3. The distributions of CO2 clouds inferred from OMEGA and CRISM are consistent with each other and match at first order the distribution of high altitude (>60 km) clouds derived from previous studies. At second order, discrepancies are observed. We report the identification of H2O clouds extending up to 80 km altitude, which could explain part of these discrepancies: both CO2 and H2O clouds can exist at high, mesospheric altitudes. CRISM observations of afternoon CO2 clouds display morphologies resembling terrestrial cirrus, which generalizes a previous result to the whole equatorial clouds season. Finally, we show that morning OMEGA observations have been previously misinterpreted as evidence for cumuliform, and hence potentially convective, CO2 clouds.

  10. Biological dosimetry after H2O2/L-histidine treatment

    Hausmann, Michael; Lentfer, Heiko; Wolf, Dietmar; Bauer, Eckhard; Aldinger, Klaus; Greulich, Karl-Otto; Cremer, Christoph G.


    In biological dosimetry after radiation or chemical exposure, it has been well established to estimate exposure doses from the relative rate of aberrant chromosomes, especially dicentric chromosomes in a given number of cells. For this purpose, dose-efficiency curves depending on laboratory parameters (e.g. preparation technique, analysis procedure etc.) have to be measured under standard conditions. For statistical reasons, a high number of chromosomes or cells, respectively, has to be evaluated. For a Chinese hamster cell line (CO60) as a typical model system in mutation research, a dose efficiency relation after H2O2/L-histidine treatment of the cells was determined using the Heidelberg slit-scan flow fluorometer. This technique has the advantage that several thousand chromosomes can be automatically analyzed in a very short time. As expected, for low doses of H2O2/L-histidine exposure, a nearly linear dependence of the relative number of dicentric chromosomes to the concentration of H2O2 was obtained. In order to correlate the relative number of dicentric chromosomes to the relative number of double strand breaks, the cells were analyzed by the technique of the neutral comet assay. The dose dependent `tail moment' obtained from the comet assay also showed a linear behavior. This confirmed the results obtained by slit-scan flow fluorometry. Furthermore, the linear dependence of the dose efficiency curve was well compatible to results obtained by visual counting by means of a fluorescence microscope. In this case chromosome 1 of the Chinese hamster cell line DON was specifically labelled by fluorescence in situ hybridization.

  11. Redetermination of metarossite, CaV5+2O6·2H2O

    Anaïs Kobsch


    Full Text Available The crystal structure of metarossite, ideally CaV2O6·2H2O [chemical name: calcium divanadium(V hexaoxide dihydrate], was first determined using precession photographs, with fixed isotropic displacement parameters and without locating the positions of the H atoms, leading to a reliability factor R = 0.11 [Kelsey & Barnes (1960. Can. Mineral. 6, 448–466]. This communication reports a structure redetermination of this mineral on the basis of single-crystal X-ray diffraction data of a natural sample from the Blue Cap mine, San Juan County, Utah, USA (R1 = 0.036. Our study not only confirms the structural topology reported in the previous study, but also makes possible the refinement of all non-H atoms with anisotropic displacement parameters and all H atoms located. The metarossite structure is characterized by chains of edge-sharing [CaO8] polyhedra parallel to [100] that are themselves connected by chains of alternating [VO5] trigonal bipyramids parallel to [010]. The two H2O molecules are bonded to Ca. Analysis of the displacement parameters show that the [VO5] chains librate around [010]. In addition, we measured the Raman spectrum of metarossite and compared it with IR and Raman data previously reported. Moreover, heating of metarossite led to a loss of water, which results in a transformation to the brannerite-type structure, CaV2O6, implying a possible dehydration pathway for the compounds M2+V2O6·xH2O, with M = Cu, Cd, Mg or Mn, and x = 2 or 4.

  12. Detection and evolution of H2O ice spots on 67P/Churyumov-Gerasimenko's nucleus

    Barucci, Maria Antonieta; Filacchione, Gianrico; Fornasier, Sonia; Raponi, Andrea; Prasanna Deshapriya, Jasinghege Don; Tosi, Federico; Feller, Clement; Ciarniello, Mauro; Sierks, Holger; Capaccioni, Fabrizio; Pommerol, Antoine; Massironi, Matteo; Oklay Vincent, Nilda; Guilbert-Lepoutre, Aurelie; Fulchignoni, Marcello; Érard, Stéphane; OSIRIS Team, VIRTIS Team


    The OSIRIS (Optical, Spectroscopic, and Infrared Remote Imaging System), and VIRTIS (Visible InfraRed Thermal Imaging Spectrometer) instruments on board Rosetta spacecraft acquired a huge quantity of resolved images and spectra of the comet 67P/Churyumov-Gerasimenko, producing the most detailed maps at the highest spatial resolution of a cometary nucleus surface. After almost two years of observations, 67P was revealed as an intriguing body with a surface rich in heterogeneous geological structures, different surface properties (albedo, colors, texture, tensile strength, layers, pits, boulders…).A large quantity of bright spots of different size with high visible albedo and flat visible spectrophotometry have been identified by OSIRIS high resolution images. Comparing the image data with near-infrared spectra and modeling the spectra (using Hapke's radiative transfer model) as a mixture of H2O ice and the ubiquitios « Dark Material » present on the nucleus' surface, we were able to study at the same time the morphological, thermal and compositional properties of these areas.With this complementary study we are able to confirm the presence of H2O ice on many brighter areas distributed on the two lobes of 67P.The detected bright spots are mostly situated on consolidated dust free material surfaces, distributed on the two lobes of 67P in locations which stay longer in shadow, mostly concentrated in near equatorial latitudes. Some spots are stable for several months and others show temporal changes connected to diurnal and seasonal variations. Stability of the spots is corroborated by the temperature retrieved at the surface. The behavior of ice at these locations is in very good agreement with theoretical expectations. The majority of the detected H2O ice spots are located in the same approximate position of previously detected cometary outbursts. A general overview of these icy spots on the surface of comet 67P will be presented and discussed.

  13. Analysis of H2O in silicate glass using attenuated total reflectance (ATR) micro-FTIR spectroscopy

    Lowenstern, Jacob B.; Pitcher, Bradley W.


    We present a calibration for attenuated total reflectance (ATR) micro-FTIR for analysis of H2O in hydrous glass. A Ge ATR accessory was used to measure evanescent wave absorption by H2O within hydrous rhyolite and other standards. Absorbance at 3450 cm−1 (representing total H2O or H2Ot) and 1630 cm−1 (molecular H2O or H2Om) showed high correlation with measured H2O in the glasses as determined by transmission FTIR spectroscopy and manometry. For rhyolite, wt%H2O=245(±9)×A3450-0.22(±0.03) and wt%H2Om=235(±11)×A1630-0.20(±0.03) where A3450 and A1630 represent the ATR absorption at the relevant infrared wavelengths. The calibration permits determination of volatiles in singly polished glass samples with spot size down to ~5 μm (for H2O-rich samples) and detection limits of ~0.1 wt% H2O. Basaltic, basaltic andesite and dacitic glasses of known H2O concentrations fall along a density-adjusted calibration, indicating that ATR is relatively insensitive to glass composition, at least for calc-alkaline glasses. The following equation allows quantification of H2O in silicate glasses that range in composition from basalt to rhyolite: wt%H2O=(ω×A3450/ρ)+b where ω = 550 ± 21, b = −0.19 ± 0.03, ρ = density, in g/cm3, and A3450 is the ATR absorbance at 3450 cm−1. The ATR micro-FTIR technique is less sensitive than transmission FTIR, but requires only a singly polished sample for quantitative results, thus minimizing time for sample preparation. Compared with specular reflectance, it is more sensitive and better suited for imaging of H2O variations in heterogeneous samples such as melt inclusions. One drawback is that the technique can damage fragile samples and we therefore recommend mounting of unknowns in epoxy prior to polishing. Our calibration should hold for any Ge ATR crystals with the same incident angle (31°). Use of a different crystal type or geometry would require measurement of several H2O-bearing standards to provide a crystal

  14. Orientation of the water moiety in CF4-H2O

    Evangelisti, Luca; Feng, Gang; Gou, Qian; Guidetti, Gloria; Caminati, Walther


    The rotational spectrum of CF4-H217O has been investigated by pulsed jet Fourier transform microwave spectroscopy. A symmetric top effective rotational spectrum has been observed, similarly to the case of the parent species (W. Caminati, A. Maris, A. Dell'Erba, P.G. Favero, Angew. Chem. Int. Ed. 45 (2006) 6711). The experimental value of the 17O χaa quadrupole coupling constant, 0.54(1) MHz, allows to determine the average value of the angle between the C2 axis of H2O and the C⋯O line, β = 24°.

  15. Abatement and toxicity reduction of antimicrobials by UV/H2O2 process.

    Urbano, Vanessa Ribeiro; Peres, Marcela Souza; Maniero, Milena Guedes; Guimarães, José Roberto


    Antimicrobials are continuously detected in environmental waters and their removal is important to avoid health and microorganisms damage. In this work, the peroxidation assisted by ultraviolet radiation (UV/H2O2) was studied to verify if the process was able to degrade sulfaquinoxaline and ofloxacin antimicrobials and to remove the toxicity and the antimicrobial activity of the solution. This process was effective on degradation of the antimicrobials, despite the antimicrobial activity removal, the toxicity of the solution increased throughout the reaction time.

  16. The Influence of Salts on the Stability of Dense H2O Ices (Invited)

    Manning, C. E.; Daniel, I.


    Dense ices in the interiors of icy satellites likely grow from salty water; however, the effect of salts on these ices is poorly understood. We studied phase relations in the system H2O-NaCl at 1 molal (5.5 wt%) NaCl to assess the role of salt on ice VI and ice VII stability. Experiments were conducted in an externally heated, gas-membrane diamond-anvil cell at 22-150°C and 1-5 GPa. Phases were characterized and identified by Raman spectroscopy and optical microscopy. The melting curve of ice VI was observed from 22 to 80°C, yielding Pm = 0.00415exp(0.0190Tm), where Pm is melting pressure (in GPa), Tm is melting temperature (in Kelvins) and R = 0.999; the melting curve for ice VII, observed from 35-150°C, is described by Pm = 0.234exp(0.00700Tm) (R = 0.997). Both melting curves are steeper than the NaCl-free curves, indicating that the freezing-point depression at this bulk composition increases with pressure. The intersection of the liquidus curves indicates that the VI-VII-liquid triple point is shifted toward lower T and higher P relative to pure H2O, requiring that both ices form H2O-NaCl solid solutions. This is consistent with the observation that the 1 molal NaCl solution crystallized to a single ice VIss or ice VIIss at all solidus T ('ss' indicates solid solution). Large single crystals of ice VIss or ice VIIss could be grown by slow compression of the cell from near-liquidus to solidus conditions. Raman spectra revealed zoning of these crystals, and persistence of the zoning (days at 22°C) implies relatively slow Na+ and Cl- diffusivity. The large depression of the freezing point in a 1 molal NaCl solution has important implications for the oceans and interiors of the icy satellites of Jupiter and Saturn. Salty fluids may remain stable to much greater depth than predicted for pure H2O ices. This would promote more extensive water-rock interaction in the silicate interiors. If not limited to ice VI and VII, this behavior may suppress formation of ices

  17. Nanoporous graphene obtained by hydrothermal process in H2O2 and its application for supercapacitors

    Lv, Jinlong; Liang, Tongxiang


    Nanohole graphene oxide (NHGO) was obtained in a homogeneous aqueous mixture of graphene oxide (GO) and H2O2 at 120 °C. Supercapacitors were fabricated as the electrode material by using NHGO. A specific capacitance of 240.1 F g-1 was obtained at a current density of 1 A g-1 in 6 m KOH electrolyte and specific capacitance remained 193.6 F g-1 at the current density of 20 A g-1. This was attributed to reducing the inner space between the double-layers, enhanced ion diffusion and large specific surface area. Supercapacitor prepared with NHGO electrodes also exhibited an excellent cycle stability.

  18. HIFI Spectroscopy of H2O Submillimeter Lines in Nuclei of Actively Star-forming Galaxies

    Liu, L.; Weiß, A.; Perez-Beaupuits, J. P.; Güsten, R.; Liu, D.; Gao, Y.; Menten, K. M.; van der Werf, P.; Israel, F. P.; Harris, A.; Martin-Pintado, J.; Requena-Torres, M. A.; Stutzki, J.


    We present a systematic survey of multiple velocity-resolved H2O spectra using Herschel/Heterodyne Instrument for the Far Infrared (HIFI) toward nine nearby actively star-forming galaxies. The ground-state and low-excitation lines (E up ≤ 130 K) show profiles with emission and absorption blended together, while absorption-free medium-excitation lines (130 K ≤ E up ≤ 350 K) typically display line shapes similar to CO. We analyze the HIFI observation together with archival SPIRE/PACS H2O data using a state-of-the-art 3D radiative transfer code that includes the interaction between continuum and line emission. The water excitation models are combined with information on the dust and CO spectral line energy distribution to determine the physical structure of the interstellar medium (ISM). We identify two ISM components that are common to all galaxies: a warm ({T}{dust}∼ 40{--}70 K), dense (n({{H}})∼ {10}5{--}{10}6 {{cm}}-3) phase that dominates the emission of medium-excitation H2O lines. This gas phase also dominates the far-IR emission and the CO intensities for {J}{up}> 8. In addition, a cold ({T}{dust}∼ 20{--}30 K), dense (n({{H}})∼ {10}4{--}{10}5 {{cm}}-3), more extended phase is present. It outputs the emission in the low-excitation H2O lines and typically also produces the prominent line absorption features. For the two ULIRGs in our sample (Arp 220 and Mrk 231) an even hotter and more compact (R s ≤ 100 pc) region is present, which is possibly linked to AGN activity. We find that collisions dominate the water excitation in the cold gas and for lines with {E}{up}≤slant 300 K and {E}{up}≤slant 800 K in the warm and hot component, respectively. Higher-energy levels are mainly excited by IR pumping.

  19. H2O2-Promoted Size Growth of Sulfated TiO2 Nanocrystals

    YAN You-Jun; QIU Xiao-Qing; WANG Hui; LI Li-Ping; LI Guang-She


    Anatase nanoparticles modified by sulfate groups were synthesized using hydrother- mal method. The particles were controlled to large sizes by simply adjusting the amount of H2O2, in which HOO- ions replaced the surface sulfate groups and reduced the steric effect to promote the grain growth. The size-induced microstructural changes of the as-prepared nanoparticles were characterized using powder XRD, FT-IR, TG, and UV-vis analyses. The sulfate groups existed on anatase surface in unidentate and bidentate coordination forms. With the particle size reduction, bandgap energies of the as-prepared anatase nanoparticles decreased, and the desorption temperature of sulfate groups shifted towards lower temperatures.

  20. Spectroscopic and theoretical analysis of Pd2+-Cl--H2O system

    Podborska, Agnieszka; Wojnicki, Marek


    Time dependent density functional theory (TD-DFT) and spectrophotometric methods were used for speciation analysis in Pd2+-Cl--H2O system. It was shown, that there is an excellent harmony between TD-DFT calculated UV-VIS spectra end those registered using spectrophotometric method. It was shown, that for simple electrolyte, a several different form of Pd(II) appears simultaneously. Thanks to TD-DFT method, it was possible to deconvolution experimental UV-VIS spectrum and determination which form of Pd(II) complexes are present in the solution.

  1. Chitosan-phosphotungstic acid complex as membranes for low temperature H2-O2 fuel cell

    Santamaria, M.; Pecoraro, C. M.; Di Quarto, F.; Bocchetta, P.


    Free-standing Chitosan/phosphotungstic acid polyelectrolyte membranes were prepared by an easy and fast in-situ ionotropic gelation process performed at room temperature. Scanning electron microscopy was employed to study their morphological features and their thickness as a function of the chitosan concentration. The membrane was tested as proton conductor in low temperature H2-O2 fuel cell allowing to get peak power densities up to 350 mW cm-2. Electrochemical impedance measurements allowed to estimate a polyelectrolyte conductivity of 18 mS cm-1.

  2. H_2O and CO_2 in magmas from the Mariana arc and back arc systems

    Newman, Sally; Stolper, Edward; STERN, Robert


    We examined the H2O and CO2 contents of glasses from lavas and xenoliths from the Mariana arc system, an intraoceanic convergent margin in the western Pacific, which contains an active volcanic arc, an actively spreading back arc basin, and active behind-the-arc cross-chain volcanoes. Samples include (1) glass rims from Mariana arc, Mariana trough, and cross-chain submarine lavas; (2) glass inclusions in arc and trough phenocrysts; and (3) glass inclusions from a gabbro + anorthosite xenolith...

  3. High selectively oxidative bromination of toluene derivatives by the H2O2-HBr system

    Jie Ju; Yu Jin Li; Jian Rong Gao; Jian Hong Jia; Liang Han; Wei Jian Sheng; Yi Xia Jia


    An aqueous solution of hydrogen peroxide and hydrogen bromide illuminated by a 60 W incandescent light bulb serves as a source of bromine radicals. Various substituted toluenes (NO2,Cl, Br, H, CH3) were high selectively brominated at the benzyl position for monobromination in CH2C12 at ice water with catalyst free. This simple but effective bromination of toluene derivatives with an aqueous H2O2-HBr system is characterized with the use of inexpensive reagents and a lower impact on the environment, which make it a good alternative to the existing bromination methods.

  4. A stress tensor eigenvector projection space for the (H2O)5 potential energy surface

    Xu, Tianlv; Farrell, James; Momen, Roya; Azizi, Alireza; Kirk, Steven R.; Jenkins, Samantha; Wales, David J.


    A stress tensor eigenvector projection space is created to describe reaction pathways on the (H2O)5 MP2 potential energy surface. Evidence for the stabilizing role of the O--O bonding interactions is found from the length of the recently introduced stress tensor trajectory in the stress tensor eigenvector projection space. The stress tensor trajectories demonstrate coupling behavior of the adjoining covalent (σ) O-H and hydrogen bonds due to sharing of covalent character. Additionally, the stress tensor trajectories can show dynamic coupling effects of pairs of σ bonds and of pairs of hydrogen bonds.

  5. Possible fossil H2O liquid-ice interfaces in the Martian crust

    Soderblom, L.A.; Wenner, D.B.


    Throughout the northern equatorial region of Mars, extensive areas have been uniformly stripped, roughly to a constant depth. These terrains vary widely in their relative ages. A model is described here to explain this phenomenon as reflecting the vertical distribution of H2O liquid and ice in the crust. Under present conditions the Martian equatorial regions are stratified in terms of the stability of water ice and liquid water. This arises because the temperature of the upper 1 or 2 km is below the melting point of ice and liquid is stable only at greater depth. It is suggested here that during planetary outgassing earlier in Martian history H2O was injected into the upper few kilometers of the crust by subsurface and surface volcanic eruption and lateral migration of the liquid and vapor. As a result, a discontinuity in the physical state of materials developed in the Martian crust coincident with the depth of H2O liquid-ice phase boundary. Material above the boundary remained pristine; material below underwent diagenetic alteration and cementation. Subsequently, sections of the ice-laden zone were erosionally stripped by processes including eolian deflation, gravitational slump and collapse, and fluvial transport due to geothermal heating and melting of the ice. The youngest plains which display this uniform stripping may provide a minimum stratigraphic age for the major period of outgassing of the planet. Viking results suggest that the total amount of H2O outgassed is less than half that required to fill the ice layer, hence any residual liquid eventually found itself in the upper permafrost zone or stored in the polar regions. Erosion stopped at the old liquid-ice interface due to increased resistance of subjacent material and/or because melting of ice was required to mobilize the debris. Water ice may remain in uneroded regions, the overburden of debris preventing its escape to the atmosphere. Numerous morphological examples shown in Viking and Mariner 9

  6. Ortho/para ratio of H2O+ toward Sagittarius B2(M) revisited.

    Schilke, Peter; Lis, Dariusz C; Bergin, Edwin A; Higgins, Ronan; Comito, Claudia


    The HIFI instrument aboard the Herschel satellite has allowed the observation and characterization of light hydrides, the building blocks of interstellar chemistry. In this article, we revisit the ortho/para ratio for H2O(+) toward the Sgr B2(M) cloud core. The line of sight toward this star forming region passes through several spiral arms and the gas in the Bar potential in the inner Galaxy. In contrast to earlier findings, which used fewer lines to constrain the ratio, we find a ratio of 3, which is uniformly consistent with high-temperature formation of the species. In view of the reactivity of this ion, this matches the expectations.

  7. Removal of phenolic endocrine disrupting compounds from waste activated sludge using UV, H2O2, and UV/H2O2 oxidation processes: effects of reaction conditions and sludge matrix.

    Zhang, Ai; Li, Yongmei


    Removal of six phenolic endocrine disrupting compounds (EDCs) (estrone, 17β-estradiol, 17α-ethinylestradiol, estriol, bisphenol A, and 4-nonylphenols) from waste activated sludge (WAS) was investigated using ultraviolet light (UV), hydrogen peroxide (H2O2), and the combined UV/H2O2 processes. Effects of initial EDC concentration, H2O2 dosage, and pH value were investigated. Particularly, the effects of 11 metal ions and humic acid (HA) contained in a sludge matrix on EDC degradation were evaluated. A pseudo-first-order kinetic model was used to describe the EDC degradation during UV, H2O2, and UV/H2O2 treatments of WAS. The results showed that the degradation of the 6 EDCs during all the three oxidation processes fitted well with pseudo-first-order kinetics. Compared with the sole UV irradiation or H2O2 oxidation process, UV/H2O2 treatment was much more effective for both EDC degradation and WAS solubilization. Under their optimal conditions, the EDC degradation rate constants during UV/H2O2 oxidation were 45-197 times greater than those during UV irradiation and 11-53 times greater than those during H2O2 oxidation. High dosage of H2O2 and low pH were favorable for the degradation of EDCs. Under the conditions of pH = 3, UV wavelength = 253.7 nm, UV fluence rate = 0.069 mW cm(-2), and H2O2 dosage = 0.5 mol L(-1), the removal efficiencies of E1, E2, EE2, E3, BPA, and NP in 2 min were 97%, 92%, 95%, 94%, 89%, and 67%, respectively. The hydroxyl radical (OH) was proved to take the most important role for the removal of EDCs. Metal ions in sludge could facilitate the removal of EDCs during UV/H2O2 oxidation. Fe, Ag, and Cu ions had more obvious effects compared with other metal ions. The overall role of HA was dependent on the balance between its competition as organics and its catalysis/photosensitization effects. These indicate that the sludge matrix plays an important role in the degradation of EDCs.

  8. Analysis of Global Expression Profiles of Arabidopsis Genes Under Abscisic Acid and H2O2 Applications

    Peng-Cheng Wang; Yan-Yan Du; Guo-Yong An; Yun Zhou; Chen Miao; Chun-Peng Song


    To gain insight into the coordination of gene expression profiles under abscisic acid (ABA) and H2O2 applications,global changes in gene expression in response to ABA and H2O2 in Arabidopsis seedlings were investigated using GeneChip (Santa Clara, CA, USA) arrays. Among over 24 000 genes present in the arrays, 459 transcripts were found to be significantly increased, whereas another 221 decreased following H2O2 treatment compared with control. Similar to treatment with H2O2, ABA treatment elevated the transcription of 391 genes and repressed that of 322 genes. One hundred and forty-three upregulated genes and 75 downregulated genes were shared between the two treatments and these genes were mainly involved in metabolism, signal transduction, transcription, defense, and resistance. Only two genes, which encode an APETALA2/dehydration-responsive element binding protein (AP2/DREBP) family transcriptional factor and a late embryogenesisabundant protein, were downregulated by H2O2, but upregulated by ABA. These results suggest that, similar to ABA, H2O2 plays a global role in gene transcription of Arabidopsisseedlings. The transcriptional responses induced by the application of exogenous ABA and H2O2 overlapped substantially. These two treatments regulated most of the downstream genes in a coordinated manner.

  9. Systemic induction of H2O2 in pea seedlings pretreated by wounding and exogenous jasmonic acid

    LIU; Yan; HUANG; Weidong; ZHAN; Jicheng; PAN; Qiuhong


    Pea seedlings (Pisum sativum L.) were used as materials to test the timings and compartments of hydrogen peroxide (H2O2) triggered by wounding and exogenous jasmonic acid (JA). The results showed that H2O2 could be systemically induced by wounding and exogenous JA. H2O2 increased within 1 h and reached the peak 3-5 h after wounding in either the wounded leaves or the unwounded leaves adjacent to the wounded ones and the inferior leaves far from the wounded ones. After this, H2O2 decreased and recovered to the control level 12 h after wounding. The activities of antioxidant enzymes, however, were rapidly increased by wounding.Diphenylene iodonium (DPI), an inhibitor of NADPH oxidase, could significantly inhibit H2O2 burst that was mediated by wounding and exogenous JA. Assay of H2O2 subcellular location showed that H2O2 in response to wounding and exogenous JA was predominantly accumulated in plasma membrane, cell wall and apoplasmic space. Numerous JA (gold particles) was found via immunogold electron microscopy to be located in cell wall and phloem zones of mesophyll cell after wounding.

  10. Single-component and binary CO2 and H2O adsorption of amine-functionalized cellulose.

    Gebald, Christoph; Wurzbacher, Jan A; Borgschulte, Andreas; Zimmermann, Tanja; Steinfeld, Aldo


    A fundamental analysis of single-component and binary CO2 and H2O adsorption of amine-functionalized nanofibrillated cellulose is carried out in the temperature range of 283-353 K and at CO2 partial pressures in the range of 0.02-105 kPa, where the ultralow partial pressure range is relevant for the direct capture of CO2 from atmospheric air. Single-component CO2 and H2O adsorption experimental data are fitted to the Toth and Guggenheim-Anderson-de Boer models, respectively. Corresponding heats of adsorption, derived from explicit solutions of the van't Hoff equation, are -50 kJ/mol CO2 and -48.8 kJ/mol H2O. Binary CO2/H2O adsorption measurements for humid air reveal that the presence of H2O at 2.55 kPa enhances CO2 adsorption, while the presence of CO2 at 0.045 kPa does not influence H2O adsorption. The energy demand of the temperature-vacuum-swing adsorption/desorption cycle for delivering pure CO2 from air increases significantly with H2O adsorption and indicates the need to reduce the hygroscopicity of the adsorbent.

  11. In situ H2O and temperature detection close to burning biomass pellets using calibration-free wavelength modulation spectroscopy

    Qu, Zhechao; Schmidt, Florian M.


    The design and application of an H2O/temperature sensor based on scanned calibration-free wavelength modulation spectroscopy (CF-WMS) and a single tunable diode laser at 1.4 µm is presented. The sensor probes two H2O absorption peaks in a single scan and simultaneously retrieves H2O concentration and temperature by least-squares fitting simulated 1f-normalized 2f-WMS spectra to measured 2f/ 1f-WMS signals, with temperature, concentration and nonlinear modulation amplitude as fitting parameters. Given a minimum detectable absorbance of 1.7 × 10-5 cm-1 Hz-1/2, the system is applicable down to an H2O concentration of 0.1 % at 1,000 K and 20 cm path length (200 ppm·m). The temperature in a water-seeded laboratory-scale reactor (670-1220 K at 4 % H2O) was determined within an accuracy of 1 % by comparison with the reactor thermocouple. The CF-WMS sensor was applied to real time in situ measurements of H2O concentration and temperature time histories (0.25-s time resolution) in the hot gases 2-11 mm above biomass pellets during atmospheric combustion in the reactor. Temperatures between 1,200 and 1,600 K and H2O concentrations up to 40 % were detected above the biofuels.

  12. H2O line mapping at high spatial and spectral resolution - Herschel observations of the VLA1623 outflow

    Bjerkeli, P; Larsson, B; Rydbeck, G; Nisini, B; Tafalla, M; Antoniucci, S; Benedettini, M; Bergman, P; Cabrit, S; Giannini, T; Melnick, G; Neufeld, D; Santangelo, G; van Dishoeck, E F


    Apart from being an important coolant, H2O is known to be a tracer of high-velocity molecular gas. Recent models predict relatively high abundances behind interstellar shockwaves. The dynamical and physical conditions of the H2O emitting gas, however, are not fully understood yet. We aim to determine the abundance and distribution of H2O, its kinematics and the physical conditions of the gas responsible for the H2O emission. The observed line profile shapes help us understand the dynamics in molecular outflows. We mapped the VLA1623 outflow, in the ground-state transitions of o-H2O, with the HIFI and PACS instruments. We also present observations of higher energy transitions of o-H2O and p-H2O obtained with HIFI and PACS towards selected outflow positions. From comparison with non-LTE radiative transfer calculations, we estimate the physical parameters of the water emitting regions. The observed water emission line profiles vary over the mapped area. Spectral features and components, tracing gas in different ...

  13. MAP kinase specifically mediates the ABA-induced H2O2 generation in guard cells of Vicia faba L

    JIANG Jing; AN Guoyong; WANG Pengcheng; WANG Pengtao; HAN Jinfeng; JIA Yanbin; SONG Chunpeng


    Mitogen-activated protein (MAP) kinase is involved in ABA- or H2O2-signaling, and H2O2 acts as intermediate in the downstream of ABA signal transduction pathway, which has recently emerged as a secondary messenger of ABA signaling. Using an epidermal strip bioassay and laser scanning confocal microscope, we provided the first evidence that MAP kinase plays an important role in H2O2 signal initial, amplification and specific targeting in response to stimuli in guard cells. ABA- or H2O2-induced Vicia faba stomatal closure was inhibited or reversed by the specific inhibitor PD98059 of MEK1/2; the guard cells were pre-incubated or -microinjected by 10 (mol·L-1 PD98059, ABA could not enhance the fluorescence intensity of H2O2 probe dichlorofluorescein (DCF). Meanwhile, after ABA induced the H2O2 accumulation in guard cells, the exogenous or intracellular PD98059 could reduce the DCF fluorescence intensity. Most interestingly, on the contrary to ABA, the DCF fluorescence intensity of guard cells treated by 100 (mol·L-1 salicylic acid (SA) was not down-regulated by PD98059, yet PD98059 did not regulate the stomatal movement being induced by light, dark or salicylic acid. These results suggest that MEK1/2 could mediate stomatal closure by abolishing the ABA-induced H2O2 generation/accumula- tion in the specific manner.

  14. Influence of dynamic vegetation on climate change and terrestrial carbon storage in the Last Glacial Maximum

    R. O'ishi


    Full Text Available When the climate is reconstructed from paleoevidence, it shows that the Last Glacial Maximum (LGM, ca. 21 000 yr ago is cold and dry compared to the present-day. Reconstruction also shows that compared to today, the vegetation of the LGM is less active and the distribution of vegetation was drastically different, due to cold temperature, dryness, and a lower level of atmospheric CO2 concentration (185 ppm compared to a preindustrial level of 285 ppm. In the present paper, we investigate the influence of vegetation change on the climate of the LGM by using a coupled atmosphere-ocean-vegetation general circulation model (AOVGCM, the MIROC-LPJ. The MIROC-LPJ is different from earlier studies in the introduction of a bias correction method in individual running GCM experiments. We examined four GCM experiments (LGM and preindustrial, with and without vegetation feedback and quantified the strength of the vegetation feedback during the LGM. The result shows that global-averaged cooling during the LGM is amplified by +13.5 % due to the introduction of vegetation feedback. This is mainly caused by the increase of land surface albedo due to the expansion of tundra in northern high latitudes and the desertification in northern middle latitudes around 30° N to 60° N. We also investigated how this change in climate affected the total terrestrial carbon storage by using offline Lund-Potsdam-Jena dynamic global vegetation model (LPJ-DGVM. Our result shows that the total terrestrial carbon storage was reduced by 597 PgC during the LGM, which corresponds to the emission of 282 ppm atmospheric CO2. In the LGM experiments, the global carbon distribution is generally the same whether the vegetation feedback to the atmosphere is included or not. However, the inclusion of vegetation feedback causes substantial terrestrial carbon storage change, especially in explaining the lowering of atmospheric CO2 during the LGM.

  15. Clostridium difficile glutamate dehydrogenase is a secreted enzyme that confers resistance to H2O2.

    Girinathan, Brintha Prasummanna; Braun, Sterling E; Govind, Revathi


    Clostridium difficile produces an NAD-specific glutamate dehydrogenase (GDH), which converts l-glutamate into α-ketoglutarate through an irreversible reaction. The enzyme GDH is detected in the stool samples of patients with C. difficile-associated disease and serves as one of the diagnostic tools to detect C. difficile infection (CDI). We demonstrate here that supernatant fluids of C. difficile cultures contain GDH. To understand the role of GDH in the physiology of C. difficile, an isogenic insertional mutant of gluD was created in strain JIR8094. The mutant failed to produce and secrete GDH as shown by Western blot analysis. Various phenotypic assays were performed to understand the importance of GDH in C. difficile physiology. In TY (tryptose yeast extract) medium, the gluD mutant grew slower than the parent strain. Complementation of the gluD mutant with the functional gluD gene reversed the growth defect in TY medium. The presence of extracellular GDH may have a functional role in the pathogenesis of CDI. In support of this assumption we found higher sensitivity to H2O2 in the gluD mutant as compared to the parent strain. Complementation of the gluD mutant with the functional gluD gene reversed the H2O2 sensitivity.

  16. The Metabolic Responses of Aspergillus flavus to N-Acetylcysteine, Ascorbate, and H2O2


    Aflatoxin, the secondary metabolite of Aspergillus flavus and A. Parasiticus, is the most toxic product in nature. In this study, N-acetylcysteine (NAC), ascorbate, and H2O2 were used to ascertain their effects on fungal metabolic esponse of A. Flavus. The results demonstrated that NAC did not affect fungal growth, but inhibited the aflatoxin B1 production, with the concomitant sporulation reduction. NAC increased the ratio of reduced glutathione (GSH) and oxidized glutathione (GSSG), hut decreased the activity of glutathione reductase (GR). Ascorbate had similar effect on fungal growth, sporulation,and GR activity, but GSH/GSSG and total glutathione (tGSH, including GSH and GSSG) were significantly increased. H2O2 at high concentration (5 mM) inhibited fungal growth, but the aflatoxin production was increased. At the same time, it reduced GR activity and enhanced tGSH. Though reductive agents had different effects on GSH metabolism, reductive conditions inhibited aflatoxin production and sporulation without any effect on fungal growth. The results in this report confirmed that the relationship between oxidative stress and aflatoxin production is theoretically important in controlling aflatoxin contamination.

  17. Garlic and H2O2 in overcoming dormancy on the vine “Cabernet Sauvignon”

    Saavedra del Aguila Juan


    Full Text Available The objective of this experiment was to evaluate the effect of garlic extract, H2O2 and hydrogen cyanamide on dormancy break, budding and maturation of “Cabernet Sauvignon” in the Campaign Region – Brazil. In late winter 2014 and after drought pruning were performed spraying in the bud: T1 – distilled water (control; T2 – 3.0% of hydrogen cyanamide; T3 – 18.0% H2O2; and T4 – 3.0% garlic extract. It was evaluated in the field: the number of sprouted buds per plant, number of bunches per plant and weight of bunches per plant; and laboratory: on ripening, performed weekly from the color change of 360 berries per treatment for analyzes solids soluble – SS (Brix pH and titratable acidity – TA (% tartaric acid. It was observed that the vines of treatment T4 (3.0% garlic extract, showed higher percentage of buds sprouting (63 shoots plant−1. Already at the number of clusters and weight per plant, there were no statistical differences between all treatments. The results obtained in the laboratory to SS, pH and TA did not differ statistically for the four tested treatments.

  18. Protective effect of enzymatic extracts from microalgae against DNA damage induced by H2O2.

    Karawita, Rohan; Senevirathne, Mahinda; Athukorala, Yasantha; Affan, Abu; Lee, Young-Jae; Kim, Se-Kwon; Lee, Joon-Baek; Jeon, You-Jin


    The enzymatic extracts from seven species of microalgae (Pediastrum duplex, Dactylococcopsis fascicularis, Halochlorococcum porphyrae, Oltmannsiellopsis unicellularis, Achnanthes longipes, Navicula sp. and Amphora coffeaeformis) collected from three habitats (freshwater, tidal pool, and coastal benthic) at Jeju Island in Korea were investigated for their antioxidant activity. Of the extracts tested, the AMG 300 L (an exo 1, 4-alpha-D-glucosidase) extract of P. duplex, the Viscozyme extract of Navicula sp., and the Celluclast extract of A. longipes provided the most potential as antioxidants. Meanwhile, the Termamyl extract of P. duplex in an H(2)O(2) scavenging assay exhibited an approximate 60% scavenging effect. In this study, we report that the DNA damage inhibitory effects of P. duplex (Termamyl extract) and D. fascicularis (Kojizyme extract) were nearly 80% and 69% respectively at a concentration of 100 microg/ml. Thus, it is suggested that the microalgae tested in this study yield promising DNA damage inhibitory properties on mouse lymphoma L 5178 cells that are treated with H(2)O(2). Therefore, microalgae such as P. duplex may be an excellent source of naturally occurring antioxidant compounds with potent DNA damage inhibition potential.

  19. Surface abundance change in vacuum ultraviolet photodissociation of CO2 and H2O mixture ices.

    Kinugawa, Takashi; Yabushita, Akihiro; Kawasaki, Masahiro; Hama, Tetsuya; Watanabe, Naoki


    Photodissociation of amorphous ice films of carbon dioxide and water co-adsorbed at 90 K was carried out at 157 nm using oxygen-16 and -18 isotopomers with a time-of-flight photofragment mass spectrometer. O((3)P(J)) atoms, OH (v = 0) radicals, and CO (v = 0,1) molecules were detected as photofragments. CO is produced directly from the photodissociation of CO(2). Two different adsorption states of CO(2), i.e., physisorbed CO(2) on the surface of amorphous solid water and trapped CO(2) in the pores of the film, are clearly distinguished by the translational and internal energy distributions of the CO molecules. The O atom and OH radical are produced from the photodissociation of H(2)O. Since the absorption cross section of CO(2) is smaller than that of H(2)O at 157 nm, the CO(2) surface abundance is relatively increased after prolonged photoirradiation of the mixed ice film, resulting in the formation of a heterogeneously layered structure in the mixed ice at low temperatures. Astrophysical implications are discussed.

  20. Hydrothermal synthesis, electrochemical properties and calculation of complex { Cu[ PHBA ]2 ( H2O)3 } (H2O)3%配合物{Cu[PHBA]2(H2O)3}(H2O)3的水热合成、晶体结构、电化学分析及量化计算

    刘雄祥; 李昶红



  1. Synthesis and Crystal Structure of [La(BTC)(H2O)6]n

    WEN Yi-Hang; CHENG Jian-Kai; FENG Yun-Long; ZHANG Jian; LI Zhao-Ji; YAO Yuan-Gen


    The title compound, [La(BTC)(H2O)6]n 1 (H3BTC = benzene-1,3,5-tricarboxylic acid), has been synthesized by the hydrothermal reaction of La(NO3)3·3H2O with H3BTC and Na2CO3, and its structure was determined by single-crystal X-ray diffraction. The crystal structure is of monoclinic, space group Cc with a = 11.5289(3), b = 18.0383(7), c = 7.3507(3)(A), β = 119.5680(10)o, V = 1329.59(8)(A)3, C9H15LaO12, Mr = 454.12, Z = 4, Dc = 2.269 g/cm3, μ = 3.280 mm-1, Flack parameter = 0.07(4), F(000) = 888, R = 0.0316 and wR = 0.0774 for 1312 observed reflections(I > 2σ(I)). Complex 1 features a one-dimensional (1-D) parallel ribbon-like structure. There are extensive hydrogen-bonding interactions involving coordinated water molecules and free carboxylate oxygen atoms. In addition, π-π interactions via benzoic multicarboxylate ligands are discussed. These non-covalent interactions lead to the formation of a 3-D framework.

  2. Redetermination of junitoite, CaZn2Si2O7·H2O

    Hexiong Yang


    Full Text Available The crystal structure of the mineral junitoite, ideally CaZn2Si2O7·H2O (calcium dizinc disilicate monohydrate, was first determined by Hamilton & Finney [Mineral. Mag. (1985, 49, 91–95] based on the space group Ama2, yielding a reliability factor R of 0.10, with isotropic displacement parameters for all non-H atoms. The present study reports a structure redetermination of junitoite using single-crystal X-ray diffraction data from a natural sample, demonstrating that the space group of this mineral is actually Aea2, which can be attained simply by shifting the origin. Topologically, the structure models in the space groups Aea2 and Ama2 are analogous, consisting of chains of corner-sharing ZnO4 tetrahedra parallel to the b axis, cross-linked by Si2O7 tetrahedral dimers (the site symmetry of the bridging O atom is ..2 along a and c, forming a three-dimensional framework. The Ca2+ cations (site symmetry ..2 are situated in cavities of the framework and are bonded to five O atoms and one H2O molecule (site symmetry ..2 in a distorted octahedral coordination environment. However, some bond lengths, especially for the SiO4 tetrahedron, are noticeably different between the two structure models. Hydrogen bonding in junitoite is found between the water molecule and a framework O atom.

  3. The application of 2H2O to measure skeletal muscle protein synthesis

    Fluckey James D


    Full Text Available Abstract Skeletal muscle protein synthesis has generally been determined by the precursor:product labeling approach using labeled amino acids (e.g., [13C]leucine or [13C]-, [15N]-, or [2H]phenylalanine as the tracers. Although reliable for determining rates of protein synthesis, this methodological approach requires experiments to be conducted in a controlled environment, and as a result, has limited our understanding of muscle protein renewal under free-living conditions over extended periods of time (i.e., integrative/cumulative assessments. An alternative tracer, 2H2O, has been successfully used to measure rates of muscle protein synthesis in mice, rats, fish and humans. Moreover, perturbations such as feeding and exercise have been included in these measurements without exclusion of common environmental and biological factors. In this review, we discuss the principle behind using 2H2O to measure muscle protein synthesis and highlight recent investigations that have examined the effects of feeding and exercise. The framework provided in this review should assist muscle biologists in designing experiments that advance our understanding of conditions in which anabolism is altered (e.g., exercise, feeding, growth, debilitating and metabolic pathologies.

  4. H$_2$O maser emission from bright rimmed clouds in the northern hemisphere

    Valdettaro, R; Brand, J; Cesaroni, R


    We report the results of a multi-epoch survey of water maser observations at 22.2 GHz with the Medicina radiotelescope from 44 bright rimmed clouds (BRCs) of the northern hemisphere identified by Sugitani et al. (1989) as potential sites of star formation. The data span 16 years of observations and allow to draw conclusions about the maser detection rate in this class of objects. In spite of the relatively high far-infrared luminosities of the embedded sources ($L_{\\rm FIR}\\ga 10^2$ L$_\\odot$), H$_2$O maser emission was detected towards three globules only. Since the occurrence of water masers is higher towards bright IRAS sources, the lack of frequent H$_2$O maser emission is somewhat surprising if the suggestion of induced intermediate- and high-mass star formation within these globules is correct. The maser properties of two BRCs are characteristic of exciting sources of low-mass, while the last one (BRC~38) is consistent with an intermediate-mass object. We argue that most BRCs host young stellar objects ...

  5. Oxidation Process of H 2 O /UV for COD Reduction of Wastewater from Soybean Tofu Production

    Komala Pontas


    Full Text Available Chemical Oxygen Demand (COD reduction of wastewater from soybean tofu production was studied by conducting advanced oxidation process (AOP using hydrogen peroxide with UV radiation catalysts in a closed cylindrical glass reactor. The hydroxyl radical (*OH concentration from H2O decomposition was modeled, and exponential trends were found for the *OH concentration over radiation time and operation temperature. As a result, it was found that the maximal *OH concentration was 0.209 mol L-12 at 240 minutes and 50 °C. The *OH concentration exponentially increased following rise in operation temperature. The H2O /UV AOP application reduced COD concentration to approximately 42.41% from 10,545 to 6,073.2 mol L-12 at 240 minutes and 50 °C. In addition, the pseudo second order kinetics is a reliable model to present the COD reduction kinetics with the correlation coefficient R in the range of 95.9 to 99.4%. The kinetics constant increased with rise in operation temperature, and it was approximately 2.30E-07, 2.590E-07, and 3.03E-07 L mg-1 min-1 for 30, 40, and 50 °C, respectively. The activation energy of COD reduction obtained was approximately 0.0138 J mol-1.