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Sample records for acidic chloride media

  1. Corrosion Study of Stainless Steels in Peracetic Acid Bleach Media With and Without Chloride and Chelant

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    Rohtash

    2014-12-01

    Full Text Available The paper industries are adopting non-chlorine containing chemicals e.g. peroxide, ozone, peracids etc. as alternate of chlorine based bleach chemicals e.g. chlorine and chlorine dioxide etc. with the aim of eco-friend atmospheres. Changeover to the new chemicals in the bleaching process is likely to affect the metallurgy of the existing bleach plants due to change in the corrosivity of the media. Accordingly, corrosion investigations were performed in a peracid namely peracetic acid to test the suitability of austenitic stainless steels 654SMO, 265SMO, 2205, 317L and 316L. The performance of above stainless steels was evaluated through long term immersion tests and Electrochemical polarization measurements in peracetic acid (PAA bleach media at pH value 4 maintaining concentration 0.2 % as active oxygen along with three chloride levels 0, 500 and 1000 ppm in pulp-free laboratory. To study the effect of corrosion inhibitors with extending limit of chloride in liquors, measurements were also made with two types of chelants- EDTA & MgSO4. The results showed that corrosivity of PAA reduced by addition of chelant while increased with concentration of Cl¯. The results also exhibited that EDTA is better inhibitor than MgSO4.

  2. Prediction and measurement of multi-metal electrodeposition rates and efficiencies in aqueous acidic chloride media

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    Pilone, D. [Department of Chemical Engineering, Imperial College London, London SW7 2AZ (United Kingdom); Kelsall, G.H. [Department of Chemical Engineering, Imperial College London, London SW7 2AZ (United Kingdom)]. E-mail: g.kelsall@imperial.ac.uk

    2006-05-05

    A novel process is being developed for metal recovery from waste electrical and electronic equipment (WEEE) and involving a leach reactor coupled to an electrochemical reactor. Metals such as Ag, Au, Cu, Pb, Pd, Sn, etc. are dissolved from shredded WEEE in an acidic aqueous chloride electrolyte by oxidizing them with aqueous dissolved chlorine species. In the electrochemical reactor: (i) chlorine is generated at the anode for use as the oxidant in the leach reactor, and, simultaneously (ii) at the cathode, the dissolved metals are electrodeposited from the leach solution. The Butler-Volmer equation was used to provide predictions of the electrode potential dependences of partial current densities, and hence total current densities, current efficiencies and alloy compositions, for acidic aqueous chloride electrolytes containing Ag(I), Au(III), Cu(II), Fe(III), Pb(II), Pd(IV) and Sn(IV) species, together with dissolved chlorine. With judicious choice of kinetic parameters, the predicted total current density-electrode potential behaviour of such solutions was in good agreement with experimental data for a rotating Pt disc electrode. Reduction of dissolved chlorine at a Pt rotating disc electrode exhibited mass transport controlled behaviour, in agreement with Levich's equation over the potential range 0.3-0.9 V (SHE). This could form the basis of a linear sensor, possibly using a microelectrode for measurement and control of the dissolved chlorine concentration in the efflux of leach reactors and inlet to cathodes of the electrowinning reactors, in the envisaged process.

  3. Mathematical modeling of cadmium(II) solvent extraction from neutral and acidic chloride media using Cyanex 923 extractant as a metal carrier.

    Science.gov (United States)

    Leopold, A A; Coll, M T; Fortuny, A; Rathore, N S; Sastre, A M

    2010-10-15

    This paper describes experimental work and the mathematical modeling of solvent extraction of cadmium(II) from neutral and acidic aqueous chloride media with a Cyanex 923 extractant in Exxol D-100. Solvent extraction experiments were carried out to analyze the influence of variations in the composition of the aqueous and organic phases on the efficiency of cadmium(II) extraction. In neutral and acidic chloride conditions, the extraction of cadmium(II) by the organophosphorous extractant Cyanex 923 (L) is based on the solvation mechanism of neutral H(n)CdCl((2+n)) species and the formation of H(n)CdCl((2+n))L(q) complexes in the organic phase, where n=0, 1, 2 and q=1, 2. The mathematical model of cadmium(II) extraction was derived from the mass balances and chemical equilibria involved in the separation system. The model was computed with the Matlab software. The equilibrium parameters for metal extraction, i.e. the stability constants of the aqueous Cd-Cl complexes, the formation constants of the acidic Cd-Cl species and the metal equilibrium extraction constants, were proposed. The optimized constants were appropriate, as there was good agreement when the model was fitted to the experimental data for each of the experiments.

  4. Mathematical modeling of cadmium(II) solvent extraction from neutral and acidic chloride media using Cyanex 923 extractant as a metal carrier

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    Leopold, A.A., E-mail: agnieszka.leopold@upc.edu [Department of Chemical Engineering, Universitat Politecnica de Catalunya, EPSEVG, Av. Victor Balaguer s/n, 08800 Vilanova i la Geltru (Spain); Coll, M.T.; Fortuny, A.; Rathore, N.S. [Department of Chemical Engineering, Universitat Politecnica de Catalunya, EPSEVG, Av. Victor Balaguer s/n, 08800 Vilanova i la Geltru (Spain); Sastre, A.M. [Department of Chemical Engineering, Universitat Politecnica de Catalunya, ETSEIB, Av. Diagonal 647, 08028 Barcelona (Spain)

    2010-10-15

    This paper describes experimental work and the mathematical modeling of solvent extraction of cadmium(II) from neutral and acidic aqueous chloride media with a Cyanex 923 extractant in Exxol D-100. Solvent extraction experiments were carried out to analyze the influence of variations in the composition of the aqueous and organic phases on the efficiency of cadmium(II) extraction. In neutral and acidic chloride conditions, the extraction of cadmium(II) by the organophosphorous extractant Cyanex 923 (L) is based on the solvation mechanism of neutral H{sub n}CdCl{sub (2+n)} species and the formation of H{sub n}CdCl{sub (2+n)}L{sub q} complexes in the organic phase, where n = 0, 1, 2 and q = 1, 2. The mathematical model of cadmium(II) extraction was derived from the mass balances and chemical equilibria involved in the separation system. The model was computed with the Matlab software. The equilibrium parameters for metal extraction, i.e. the stability constants of the aqueous Cd-Cl complexes, the formation constants of the acidic Cd-Cl species and the metal equilibrium extraction constants, were proposed. The optimized constants were appropriate, as there was good agreement when the model was fitted to the experimental data for each of the experiments.

  5. A comparative study of chelating and cationic ion exchange resins for the removal of palladium(II) complexes from acidic chloride media.

    Science.gov (United States)

    Hubicki, Zbigniew; Wołowicz, Anna

    2009-05-30

    The increasing demand for palladium for technological application requires the development of ion exchange chromatography. Recently ion exchange chromatography has developed largely as a result of new types of ion exchangers available on the market of which two types are widely applied. One of them are selective (chelating) and modified ion exchangers and the other one are liquid exchangers. Two types of ion exchange resins such as chelating (Lewatit TP 214, Purolite S 920) and cationic (Chelite S, Duolite GT 73) ion exchangers are used for the recovery of palladium(II) complexes from chloride media (0.1-2.0M HCl-1.0M NaCl-0.0011 M Pd(II); 0.1-2.0M HCl-2.0M NaCl-0.0011M Pd(II)). The influence of concentration of hydrochloric acid, sodium chloride as well as the phase contact time on the degree of recovery of palladium(II) complexes was studied. Moreover, the amount of palladium(II) chlorocomplexes sorbed onto ion exchangers, the working ion exchange capacities and the weight and bed distribution coefficients were calculated in order to judge which of two types of resins possesses the best performance towards palladium(II) complexes.

  6. Effect of Ammonium Molybdate Inhibition on Corrosion Behaviour of Mild Steel in Chloride and Sulphide Media

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    Ayo S. Afolabi

    2010-10-01

    Full Text Available The corrosion inhibition of mild steel in 3.0 M sodium chloride and 0.5 M sodium sulphide using various concentrations of ammonium molybdate was investigated in this work. The inhibition effect of this reagent in these media was monitored by weight loss and pH measurements. The analyses of the weight loss results showed that the corrosion susceptibility of mild steel in 3.0 M sodium chloride was more pronounced than in 0.5 M of sodium sulphide due to the aggressive chloride ions in the former and the weak nature of the latter. Ammonium molybdate produced a better inhibition performance of mild steel in 0.5 M sodium suphide than in 3.0 M sodium chloride medium and the higher the concentration of ammonium molybdate the more the inhibition performance on mild steel in the media studied. Optimum inhibition was obtained at 2.5 M ammonium molybdate in both media. The pH values in chloride medium remained acidic throughout the exposure period while those of sulphide medium shifted to alkaline region with exposure time; an effect that was traceable to higher inhibition obtained in the latter medium.

  7. Chloride stress corrosion cracking of Alloy 600 in boric acid solutions

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    Berge, Ph. [Electricite de France, 92 - Paris la Defense (France); Noel, D.; Gras, J.M.; Prieux, B. [Electricite de France, 77 - Moret-sur-Loing (France). Direction des Etudes et Recherches

    1997-10-01

    The high nickel austenitic alloys are generally considered to have good resistance to chloride stress corrosion cracking. In the standard boiling magnesium chloride solution tests, alloys with more than 40% nickel are immune. Nevertheless, more recent data show that cracking can occur in both Alloys 600 and 690 if the solution is acidified. In other low pH media, such as boric acid solution at 100 deg C, transgranular and intergranular cracking are observed in Alloy 600 in the presence of minor concentrations of sodium chloride (2g/I). In concentrated boric acid at higher temperatures (250 and 290 deg C), intergranular cracking also occurs, either when the chloride concentration is high, or at low chloride contents and high oxygen levels. The role of pH and a possible specific action of boric acid are discussed, together with the influence of electrochemical potential. (author) 21 refs.

  8. Hexavalent chromium recovery by liquid–liquid extraction with 2-octylaminopyridine from acidic chloride media and its sequential separation from other heavy toxic metal ions

    OpenAIRE

    C.P. Mane; S.V. Mahamuni; S. S. Kolekar; Han, S. H.; M. A. ANUSE

    2016-01-01

    A systematic study of extraction of chromium(VI) with 2-octylaminopyridine (2-OAP) in xylene at room temperature has been conducted. Quantitative extraction of chromium(VI) was observed in the 0.4–0.8 M concentration range of hydrochloric acid. From the extracted complex species in the organic phase, chromium(VI) was back extracted with 7 N ammonia (3 × 10 mL), and was determined by spectrophotometric method. Various parameters such as 2-OAP concentration, equilibrium period, effect of variou...

  9. Hexavalent chromium recovery by liquid–liquid extraction with 2-octylaminopyridine from acidic chloride media and its sequential separation from other heavy toxic metal ions

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    C.P. Mane

    2016-11-01

    Full Text Available A systematic study of extraction of chromium(VI with 2-octylaminopyridine (2-OAP in xylene at room temperature has been conducted. Quantitative extraction of chromium(VI was observed in the 0.4–0.8 M concentration range of hydrochloric acid. From the extracted complex species in the organic phase, chromium(VI was back extracted with 7 N ammonia (3 × 10 mL, and was determined by spectrophotometric method. Various parameters such as 2-OAP concentration, equilibrium period, effect of various diluents, aqueous: organic volume ratio, acidity and diverse ions were studied. The extraction reaction proceeds with ion-pair formation and the stoichiometry of extracted species was found to be [(2OAPH+ CrO3Cl−](org. The separation and determination of chromium(VI from associated and toxic metals in binary, ternary and multicomponent mixture were carried out. The method permits the sequential separation of chromium(VI from other toxic metals and has been used to separate and determine chromium(VI from alloys, and effluent water samples from tannery industries.

  10. Solvolyses of Benzoyl Chlorides in Weakly Nucleophilic Media

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    Haldon Carl Harris

    2011-07-01

    Full Text Available Rate constants and activations parameters are reported for solvolyses of p-Z-substituted benzoyl chlorides (1, Z = OMe, Me, H, and Cl in 97% w/w hexafluoroisopropanol-water (97H. Additional kinetic data are reported for solvolyses in acetic and formic acids. Plots of log k vs. σp in 97H are consistent with previous research showing that a cationic reaction channel is dominant, even for solvolyses of 1, Z = NO2. A benzoyl cation intermediate was trapped by Friedel-Crafts reaction with 1,3,5-trimethoxybenzene in hexafluoroisopropanol. The results are explained by an SN2-SN1 spectrum of mechanisms with variations in nucleophilic solvent assistance. Ab initio calculations of heterolytic bond dissociation energies of various chloro- and fluoro-substituted and other benzoyl chlorides are correlated with log k for solvolyses.

  11. Liquid-liquid extraction of Cd(II) from pure and Ni/Cd acidic chloride media using Cyanex 921: a selective treatment of hazardous leachate of spent Ni-Cd batteries.

    Science.gov (United States)

    Choi, Seon-Young; Nguyen, Viet Tu; Lee, Jae-Chun; Kang, Ho; Pandey, B D

    2014-08-15

    The present paper is focused on solvent extraction of hazardous Cd(II) from acidic chloride media by Cyanex 921, a new extractant mixed with 10% (v/v) TBP in xylene. The optimum conditions for extraction and stripping of Cd(II) were investigated with an aqueous feed of 0.1 mol/L Cd(II) in 2.0 mol/L HCl. McCabe-Thiele diagram was in good agreement with the simulation studies, showing the quantitative extraction (99.9%) of Cd(II) within two counter-current stages utilizing 0.30 mol/L Cyanex 921 at O/A ratio of 3/2 in 10 min. Stoichiometry of the complexes extracted was determined and confirmed by numerical treatment and graphical method, revealing the formation of HCdCl3 · 2L and HCdCl3 · 4L for Cyanex 921(L) concentration in the range 0.03-0.1 mol/L and 0.1-1.0 mol/L, respectively. The thermodynamic parameters for the extraction of cadmium were also determined. The stripping efficiency of cadmium from the loaded organic with 0.10 mol/L HCl was 99.6% in a three-stage counter-current process at an O/A ratio of 2/3. Cyanex 921 was successfully applied for the separation of Cd(II) from Ni(II) in the simulated leach liquor of spent Ni-Cd batteries. The study demonstrates the applicability of the present hydrometallurgical approach for the treatment of hazardous waste, the spent Ni-Cd batteries.

  12. Catalytic Conversion of Cellulose to Levulinic Acid by Metal Chlorides

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    Beixiao Zhang

    2010-08-01

    Full Text Available The catalytic performance of various metal chlorides in the conversion of cellulose to levulinic acid in liquid water at high temperatures was investigated. The effects of reaction parameters on the yield of levulinic acid were also explored. The results showed that alkali and alkaline earth metal chlorides were not effective in conversion of cellulose, while transition metal chlorides, especially CrCl3, FeCl3 and CuCl2 and a group IIIA metal chloride (AlCl3, exhibited high catalytic activity. The catalytic performance was correlated with the acidity of the reaction system due to the addition of the metal chlorides, but more dependent on the type of metal chloride. Among those metal chlorides, chromium chloride was found to be exceptionally effective for the conversion of cellulose to levulinic acid, affording an optimum yield of 67 mol % after a reaction time of 180 min, at 200 °C, with a catalyst dosage of 0.02 M and substrate concentration of 50 wt %. Chromium metal, most of which was present in its oxide form in the solid sample and only a small part in solution as Cr3+ ion, can be easily separated from the resulting product mixture and recycled. Finally, a plausible reaction scheme for the chromium chloride catalyzed conversion of cellulose in water was proposed.

  13. Hafnium extraction from acidic chloride solutions by Cyanex 923

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    El-Ammouri, E.; Distin, P.A. [McGill Univ., Montreal (Canada)

    1996-08-01

    Hafnium extraction from hydrochloric acid/lithium chloride solutions into Cyanex 923 in kerosene has been studied. Variables investigated were hydrochloric acid, total chloride and hafnium concentrations in the aqueous phase, and extractant/modifier (isodecanol) levels in the organic phase. Hafnium is considered to load as the tetrachloride complex forming a disolvate with Cyanex 923. Results are compared with equivalent data for zirconium extraction. 14 refs., 7 figs., 2 tabs.

  14. Synthesis and characterization of zinc chloride containing poly(acrylic acid) hydrogel by gamma irradiation

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    Park, Jong-Seok; Kuang, Jia; Gwon, Hui-Jeong; Lim, Youn-Mook; Jeong, Sung-In; Shin, Young-Min; Seob Khil, Myung; Nho, Young-Chang

    2013-07-01

    In this study, the characterization of zinc chloride incorporated into a poly(acrylic acid) (PAAc) hydrogel prepared by gamma-ray irradiation was investigated. Zinc chloride powder with different concentrations was dissolved in the PAAc solution, and it was crosslinked with gamma-ray irradiation. The effects of various parameters such as zinc ion concentration and irradiation doses on characteristics of the hydrogel formed were investigated in detail for obtaining an antibacterial wound dressing. In addition, the gel content, pH-sensitive (pH 4 or 7) swelling ratio, and UV-vis absorption spectra of the zinc particles in the hydrogels were characterized. Moreover, antibacterial properties of these new materials against Staphylococcus aureus and Escherichia coli strains were observed on solid growth media. The antibacterial tests indicated that the zinc chloride containing PAAc hydrogels have good antibacterial activity.

  15. Reactions of enolisable ketones with dichloroisocyanuric acid in absence and presence of added chloride ions – a kinetic study

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    Y. L. Kumar

    2015-01-01

    Full Text Available Kinetics of reactions of enolisable ketones (S = acetone/2-butanone with dichloroisocyanuric acid (DCICA were studied in aqueous acetic acid and perchloric acid media in absence and presence of added chloride ions. The reactions were found to be pseudo zero order and pseudo first order on [DCICA] in absence and presence of chloride ions respectively. Both in presence and absence of chloride ions, first order and fractional order in substrate and perchloric acid were observed respectively. An increase in the rate of reaction was observed with an increase in chloride ion concentration as well as acetic acid composition. The results were interpreted in terms of probable mechanisms involving (i rate-determining enol formation from the conjugate acid of the ketone (SH+ in the absence of added chloride ions and (ii rate-determining interaction of SH+ with the most effective molecular chlorine species produced by the hydrolysis of DCICA (rather than a rate-determining interaction of enol with chlorine in the presence of added chloride ions, prior to the rapid steps of product formation. DOI: http://dx.doi.org/10.4314/bcse.v29i1.12

  16. Mechanisms of solvolyses of acid chlorides and chloroformates. Chloroacetyl and phenylacetyl chloride as similarity models.

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    Bentley, T William; Harris, H Carl; Ryu, Zoon Ha; Lim, Gui Taek; Sung, Dae Dong; Szajda, Stanley R

    2005-10-28

    [reaction: see text] Rate constants and product selectivities (S = ([ester product]/[acid product]) x ([water]/[alcohol solvent]) are reported for solvolyses of chloroacetyl chloride (3) at -10 degrees C and phenylacetyl chloride (4) at 0 degrees C in ethanol/ and methanol/water mixtures. Additional kinetic data are reported for solvolyses in acetone/water, 2,2,2-trifluoroethanol(TFE)/water, and TFE/ethanol mixtures. Selectivities and solvent effects for 3, including the kinetic solvent isotope effect (KSIE) of 2.18 for methanol, are similar to those for solvolyses of p-nitrobenzoyl chloride (1, Z = NO(2)); rate constants in acetone/water are consistent with a third-order mechanism, and rates and products in ethanol/ and methanol/water mixtures can be explained quantitatively by competing third-order mechanisms in which one molecule of solvent (alcohol or water) acts as a nucleophile and another acts as a general base (an addition/elimination reaction channel). Selectivities increase for 3 as water is added to alcohol. Solvent effects on rate constants for solvolyses of 3 are very similar to those of methyl chloroformate, but acetyl chloride shows a lower KSIE, and a higher sensitivity to solvent-ionizing power, explained by a change to an S(N)2/S(N)1 (ionization) reaction channel. Solvolyses of 4 undergo a change from the addition/elimination channel in ethanol to the ionization channel in aqueous ethanol (<80% v/v alcohol). The reasons for change in reaction channels are discussed in terms of the gas-phase stabilities of acylium ions, calculated using Gaussian 03 (HF/6-31G(d), B3LYP/6-31G(d), and B3LYP/6-311G(d,p) MO theory).

  17. Modeling acid-gas generation from boiling chloride brines

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    Sonnenthal Eric

    2009-11-01

    Full Text Available Abstract Background This study investigates the generation of HCl and other acid gases from boiling calcium chloride dominated waters at atmospheric pressure, primarily using numerical modeling. The main focus of this investigation relates to the long-term geologic disposal of nuclear waste at Yucca Mountain, Nevada, where pore waters around waste-emplacement tunnels are expected to undergo boiling and evaporative concentration as a result of the heat released by spent nuclear fuel. Processes that are modeled include boiling of highly concentrated solutions, gas transport, and gas condensation accompanied by the dissociation of acid gases, causing low-pH condensate. Results Simple calculations are first carried out to evaluate condensate pH as a function of HCl gas fugacity and condensed water fraction for a vapor equilibrated with saturated calcium chloride brine at 50-150°C and 1 bar. The distillation of a calcium-chloride-dominated brine is then simulated with a reactive transport model using a brine composition representative of partially evaporated calcium-rich pore waters at Yucca Mountain. Results show a significant increase in boiling temperature from evaporative concentration, as well as low pH in condensates, particularly for dynamic systems where partial condensation takes place, which result in enrichment of HCl in condensates. These results are in qualitative agreement with experimental data from other studies. Conclusion The combination of reactive transport with multicomponent brine chemistry to study evaporation, boiling, and the potential for acid gas generation at the proposed Yucca Mountain repository is seen as an improvement relative to previously applied simpler batch evaporation models. This approach allows the evaluation of thermal, hydrological, and chemical (THC processes in a coupled manner, and modeling of settings much more relevant to actual field conditions than the distillation experiment considered. The actual

  18. Modeling acid-gas generation from boiling chloride brines

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    Zhang, Guoxiang; Spycher, Nicolas; Sonnenthal, Eric; Steefel, Carl

    2009-11-16

    This study investigates the generation of HCl and other acid gases from boiling calcium chloride dominated waters at atmospheric pressure, primarily using numerical modeling. The main focus of this investigation relates to the long-term geologic disposal of nuclear waste at Yucca Mountain, Nevada, where pore waters around waste-emplacement tunnels are expected to undergo boiling and evaporative concentration as a result of the heat released by spent nuclear fuel. Processes that are modeled include boiling of highly concentrated solutions, gas transport, and gas condensation accompanied by the dissociation of acid gases, causing low-pH condensate. Simple calculations are first carried out to evaluate condensate pH as a function of HCl gas fugacity and condensed water fraction for a vapor equilibrated with saturated calcium chloride brine at 50-150 C and 1 bar. The distillation of a calcium-chloride-dominated brine is then simulated with a reactive transport model using a brine composition representative of partially evaporated calcium-rich pore waters at Yucca Mountain. Results show a significant increase in boiling temperature from evaporative concentration, as well as low pH in condensates, particularly for dynamic systems where partial condensation takes place, which result in enrichment of HCl in condensates. These results are in qualitative agreement with experimental data from other studies. The combination of reactive transport with multicomponent brine chemistry to study evaporation, boiling, and the potential for acid gas generation at the proposed Yucca Mountain repository is seen as an improvement relative to previously applied simpler batch evaporation models. This approach allows the evaluation of thermal, hydrological, and chemical (THC) processes in a coupled manner, and modeling of settings much more relevant to actual field conditions than the distillation experiment considered. The actual and modeled distillation experiments do not represent

  19. Copper(I) mediated cross-coupling of amino acid derived organozinc reagents with acid chlorides

    DEFF Research Database (Denmark)

    Hjelmgaard, Thomas; Tanner, David Ackland

    2006-01-01

    This paper describes the development of a straightforward experimental protocol for copper-mediated cross-coupling of amino acid derived beta-amido-alkylzinc iodides 1 and 3 with a range of acid chlorides. The present method uses CuCN center dot 2LiCl as the copper source and for organozinc reagent...... 1 the methodology appears to be limited to reaction with more stable acid chlorides, providing the desired products in moderate yields. When applied to organozinc reagent 3, however, the protocol is more general and provides the products in good yields in all but one of the cases tested....

  20. Reactivity Ratios of Diethyldiallylammonium Chloride with Acrylamide or Acrylic Acid

    Institute of Scientific and Technical Information of China (English)

    Li Hua LIU; Zhi Qiang LIU; Zhu Qing GONG

    2006-01-01

    The compositions of copolymers of diethyldiallylammonium chloride (DEDAAC) with acrylamide (AM), acrylic acid (AA) or sodium acrylic acid (NaAA) at low conversion were determined by elemental analysis, and the reactivity ratios of monomers in copolymerization were obtained by Kelen-Tudos method. The results showed that the reactivity ratios rDE and rAM are 0.31 and 5.27 for DEDAAC with AM, rDE and rAA are 0.28 and 5.15 for DEDAAC with AA, and rDE and rNaAA are 0.40 and 3.97 for DEDAAC with NaAA, respectively. The copolymerizations for DEDAAC with AM, AA or NaAA are non-ideal copolymerization and the products are random copolymers.

  1. The Corrosion Behaviour of WC-Co-Ru Alloys in Aggressive Chloride Media

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    J. H. Potgieter

    2014-01-01

    Full Text Available Hardmetals possess excellent wear resistance, making them suitable alloys in several industrial applications. Mine waters with both dissolved chloride and sulphate salts can be severely corrosive and can limit the application of hardmetal tools in the mining industry. Ru additions to these alloys can refine and improve selected mechanical properties, but its influence on the corrosion resistance is unknown. A series of WC-Co-Ru alloys was evaluated in different chloride containing media to investigate their corrosion resistance. Standard electrochemical corrosion tests, chronoamperometric measurements, and surface analyses with Raman spectroscopy were conducted. An increasing amount of Ru improves the corrosion resistance of all the alloys. The effect is not as dramatic as that observed with stainless steels containing Ru in corrosive media. In both corrosive media Ru decreased the cathodic Tafel constant and has a retarding influence on the cathodic part of the corrosion reaction. Raman analyses indicated the presence of tungsten oxide, hydrated tungsten oxide compounds, and CoO and Co3O4 formed on the alloy surfaces during the corrosion process.

  2. SUBSTITUTION REACTION OF HYDROXY OF CITRONELLOL WITH CHLORIDE USING A MIXTURE OF AMMONIUM CHLORIDE AND SULPHURIC ACID

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    Endah Sayekti

    2016-08-01

    Full Text Available Substitution reaction of hydroxy of citronellol with chloride using a mixture of ammonium chloride (NH4Cl and sulphuric acid (H2SO4 has been conducted. The citronellol was obtained from the reduction of citronellal using sodium borohydride (NaBH4 at room temperature for 30 minutes. Substitution of hydroxy of citronellol with chloride ion was carried out at 80 oC and molarity ratio of citronellol and NH4Cl 1:1, 1:2; 1:3; and 1:4 respectively. Identification of the product by gas chromatography-mass spectrometry (GC-MS showed that the substitution reaction produced 2-isopropyl-5-methyl-1-chlorocyclohexane compound with rendemen 64,49 % in mol ratio of 1:4. The infra red (IR analysis showed that there was a vibration at wave number 763 cm-1 which is a typical C-Cl vibrations.

  3. TESTING OF 304L STAINLESS STEEL IN NITRIC ACID ENVIRONMENTS WITH FLUORIDES AND CHLORIDES

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    Mickalonis, J.

    2010-10-04

    Impure radioactive material processed in nitric acid solutions resulted in the presence of chlorides in a dissolver fabricated from 304L stainless steel. An experimental program was conducted to study the effects of chloride in nitric acid/fluoride solutions on the corrosion of 304L stainless steel. The test variables included temperature (80, 95, and 110 C) and the concentrations of nitric acid (6, 12, and 14 M), fluoride (0.01, 0.1, and 0.2 M) and chloride (100, 350, 1000, and 2000 ppm). The impact of welding was also investigated. Results showed that the chloride concentration alone was not a dominant variable affecting the corrosion, but rather the interaction of chloride with fluoride significantly affected corrosion.

  4. Role of Citrate Ions in the Phosphonate-based Inhibitor System for Mild Steel in Aqueous Chloride Media

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    G. Gunasekaran

    2005-01-01

    Full Text Available The corrosion inhibition efficiency of phosphonic acid and its derivatives for the inhibition of corrosion of mild steel in neutral chloride media is decided by its ability to form protectivefilm over the surface. In this context, the effect of addition of metal cations and certain organic compounds, such as citrate in conjugation with phosphonic acid to impart synergistic corrosion inhibition has been explored. The experiments were carried out using various concentrations of trisodium citrate and zinc ions in an aqueous solution of 2-carboxyethyl phosphonic acid (2CEPA at 25 ppm. The corrosion characteristics have been determined using electrochemical impedance spectroscopy together with determination of corrosion rate by weight-loss method. It has been observed that a combination of inhibitive ions, namely citrate, ZCEPA, and zinc ions at 25 ppm gives 96 per cent inhibition efficiency and this corrosion inhibition is due to the formation of a protective film. By increasing the concentration of citrate beyond 25 ppm, the corrosion inhibition efficiency decreases. This paper discusses the role of citrate and zinc ions in imparting added corrosion inhibition ability using 2CEPA on the basis of experimental results.

  5. Extraction of Palladium (Ⅱ) with p-Methylphenylalkylsulfide from Aqueous Chloride Media

    Institute of Scientific and Technical Information of China (English)

    杨立; 章正熙; 刘旭辉; 郭亚莉; 二井晋; 竹内宽

    2005-01-01

    p-Methylphenylalkylsulfide of various alkyl chain length as extractant were synthesized and the extraction of palladium was examined in terms of equilibrium and kinetics. Distribution ratio of Pd was independent of alkyl chain length. For aqueous chloride media, there was a significant difference in distribution ratios for the solution of NaC1 and HC1. The results of loading test and the slope analysis suggest that the extractant and Pd (Ⅱ) form 2:1 complex. Furthermore, the extraction rate based on the volume of aqueous phase was obtained in a stirred vessel, and the rate equation was presented. Unfortunately, it was difficult to construct surfactant liquid membrane system by use of the present extractant.

  6. Optimisation of the batch reactor for the removal of cobalt ions from chloride media.

    Science.gov (United States)

    Wen Min, Soh; Hasnat, M A; Rahim, Afidah Abd; Mohamed, Norita

    2013-01-01

    A series of experiments were carried out to determine the best medium for the recovery of cobalt by means of an electrogenerative system. Use of the electrogenerative system with a chloride medium had shown promising performance with the highest free energy of -389.8 kJ mol(-1) compared to that with sulphate and nitrate media. Subsequently, the influence of catholyte concentrations on cobalt recovery using the electrogenerative process was carried out by varying the initial cobalt concentration and sodium chloride concentration. The results showed that almost 100% recovery was attained within 1-4 h of the recovery process. Influence of pH was investigated where the electrogenerative system performed best between pH 5.0 and 7.0. Maximum cell performance of 83% with 99% cobalt removal was obtained at 90 min when 100 mg L(-1) of Co(2+) in 0.5 M NaCl was taken as catholyte solution. The values of ΔH(o) and ΔS(o) of the process were evaluated as 33.41 kJ mol(-1) and 0.13 kJ mol(-1), respectively.

  7. FUEL CELL ELECTRODES FOR ACID MEDIA

    Science.gov (United States)

    fuel cell electrodes for acid media. Activated carbon electrodes were prepared, wetproofed with paraffin or Teflon, and catalyzed with platinum. The wetproofing agent was applied by immersion or electrodeposition and the catalyst applied by chemical decomposition of H2P+Cl6 solutions. Half cell studies with hydrogen anodes and oxygen (air) cathodes showed that electrochemical performance is essentially the same for paraffin and Teflontreated electrodes; however, the life of the Teflon-treated electrodes under equal conditions of load is greater than that for

  8. Integrated treatment of acid mine drainage using cryptocrystalline magnesite and barium chloride

    CSIR Research Space (South Africa)

    Masindi, Vhahangwele

    2017-08-01

    Full Text Available This study endeavours to report the efficiency of a hybrid approach in the treatment of acid mine drainage. Cryptocrystalline magnesite was used to pre-treat acid mine drainage and barium chloride was used to remove the residual sulphate through...

  9. Application of cerium chloride to improve the acid resistance of dentine.

    Science.gov (United States)

    Wegehaupt, Florian J; Sener, Beatrice; Attin, Thomas; Schmidlin, Patrick R

    2010-06-01

    To investigate the effect of cerium chloride, cerium chloride/fluoride and fluoride application on calcium release during erosion of treated dentine. Forty dentine samples were prepared from human premolars and randomly assigned to four groups (1-4). Samples were treated twice a day for 5 days, 30s each, with the following solutions: group 1 placebo, group 2 fluoride (Elmex fluid), group 3 cerium chloride and group 4 combined fluoride and cerium chloride. For the determination of acid resistance, the samples were consecutively eroded six times for 5 min with lactic acid (pH 3.0) and the calcium release in the acid was determined. Furthermore, six additional samples per group were prepared and used for EDS analysis. SEM pictures of these samples of each group were also captured. Samples of group 1 presented the highest calcium release when compared with the samples of groups 2-4. The highest acid resistance was observed for group 2. Calcium release in group 3 was similar to that of group 4 for the first two erosive attacks, after which calcium release in group 4 was lower than that of group 3. Generally, the SEM pictures showed a surface coating for groups 2-4. No deposits were observed in group 1. Although fluoride showed the best protective effect, cerium chloride was also able to reduce the acid susceptibility of dentine significantly, which merits further investigation. Copyright 2010 Elsevier Ltd. All rights reserved.

  10. Gastroprotective Properties of Manganese Chloride on Acetic Acid ...

    African Journals Online (AJOL)

    Dr Olaleye

    factors causes ulcer, gastric acid secretion still remains an important factor in ... acid hyper secretion can also cause problems such as ... and many diseases including osteoporosis, ..... amount of manganese delivered in children's parenteral.

  11. Leaching of complex sulphide concentrate in acidic cupric chloride solutions

    Institute of Scientific and Technical Information of China (English)

    M. TCHOUMOU; M. ROYNETTE

    2007-01-01

    The chemical analysis of a complex sulphide concentrate by emission spectrometry and X-ray diffraction shows that it contains essentially copper, lead, zinc and iron in the form of chalcopyrite, sphalerite and galena. A small amount of pyrite is also present in the ore but does not be detected with X-ray diffraction. The cupric chloride leaching of the sulphide concentrate at various durations and solid/liquid ratios at 100 ℃ shows that the rate of dissolution of the ore is the fastest in the first several hours, and after 12 h it does not evolve significantly. If oxygen is excluded from the aqueous cupric chloride solution during the leaching experiment at 100 ℃, the pyrite in the ore will not be leached. The determination of principal dissolved metals in the leaching liquor by flame atomic absorption spectrometry, and the chemical analysis of solid residues by emission spectrometry and X-ray diffraction allow to conclude that the rate of dissolution of the minerals contained in the complex sulphide concentrate are in the order of galena>sphalerite>chalcopyrite.

  12. p-Coumaric acid, a common dietary polyphenol, protects cadmium chloride-induced nephrotoxicity in rats.

    Science.gov (United States)

    Navaneethan, Dhanalakshmi; Rasool, Mahaboobkhan

    2014-03-01

    The present study was conducted to elucidate the protective role of p-coumaric acid, a common dietary polyphenol against cadmium induced nephrotoxicity in rats. For the purpose of comparison, a standard reference drug silymarin (50 mg/kg b. wt) was used. In this experiment, the animals were divided into four groups, with each consisting of six animals. The animals in Group I animals received saline and served as a control group and those in Group II received cadmium chloride (3 mg/kg b. wt) subcutaneously once daily for 3 weeks, but Group III and IV animals received cadmium chloride followed by p-coumaric acid (100 mg/kg b. wt, oral) and silymarin (50 mg/kg b. wt, oral), respectively, daily for 3 weeks. At the end of the treatment, the animals were sacrificed, and the blood and kidney samples were collected. The results obtained in this study revealed the fact that the levels of lipid peroxidation, lysosomal enzymes, glycoprotein, cadmium and metallothionein were increased in the cadmium chloride alone treated rats and antioxidant status was found to be decreased, when compared to the control group. The levels of kidney functional markers (urea, uric acid and creatinine) were also found to be abnormal in serum and urine of cadmium chloride alone treated rats. On the other hand, the administration of p-coumaric acid along with cadmium chloride significantly protected the biochemical alterations as observed in the cadmium chloride alone treated rats as evidenced by histopathology. Thus, the oral administration of p-coumaric acid significantly protected the cadmium-induced nephrotoxicity in rats.

  13. Floc properties and membrane fouling of polyferric silicate chloride and polyferric chloride: the role of polysilicic acid.

    Science.gov (United States)

    Dong, Hongyu; Gao, Baoyu; Yue, Qinyan; Sun, Shenglei; Wang, Yan; Li, Qian

    2015-03-01

    Impact of polysilicic acid (pSi) in polyferric silicate chloride (PFSiC) on coagulation-ultrafiltration process was investigated in comparison with polyferric chloride (PFC). The Fe(III) species distribution in PFSiC and PFC was measured by a timed complexation spectroscopy method. Characteristics of flocs produced by PFSiC and PFC were studied using a laser diffraction particle sizing device. Moreover, membrane fouling was evaluated using a dead-end batch ultrafiltration unit under two operation modes, coagulation-ultrafiltration (C-UF) and coagulation-sedimentation-ultrafiltration (CSUF). The results indicated that PFSiC with various Si/Fe ratios had better turbidity removal efficiency but inferior organic matter removal. Flocs formed by PFSiC were larger than those by PFC. In case of PFSiC, floc size increased with Si/Fe ratio increasing. PFSiC with various Si/Fe ratios resulted in more compact and weaker flocs than PFC. Ultrafiltration experiments indicated that under C-UF mode, PFSiC with Si/Fe ratios of 0.07 and 0.10 presented better membrane performance than PFC. Under CSUF mode, addition of pSi could alleviate membrane fouling.

  14. CATALYTIC ESTERIFICATION OF CARBOXYLIC ACIDS WITH ALCOHOLS BY SULFO—POLYVINYL CHLORIDE

    Institute of Scientific and Technical Information of China (English)

    YuShanxin; ZHAOZongbao; 等

    1993-01-01

    Polyvinyl Chloride reacted with chlorosulfonic acid to from a polymer catalyst PVC-SO3H.This polymer catalyst was found to have high activity for resterification reaction between carboxylic acids and alcohols.This paper deals with the conditions in synthesis of n-butlyacetate catalyzed with PVC-SO3H.The PVC-SO3H was used as a catalyst for preparing 11 esters of acetic acid,propionic acid and butyric acid with the yields of 82-92%.

  15. Electrochemical oxidation of synthetic tannery wastewater in chloride-free aqueous media

    Energy Technology Data Exchange (ETDEWEB)

    Costa, Carla Regina [Departamento de Quimica, Faculdade de Filosofia, Ciencias e Letras de Ribeirao Preto, Universidade de Sao Paulo, CEP 14040-901, Ribeirao Preto, SP (Brazil); Montilla, Francisco; Morallon, Emilia [Departamento de Quimica Fisica, Universidad de Alicante, Apartado de Correos 99, E-03080 Alicante (Spain); Olivi, Paulo, E-mail: olivip@ffclrp.usp.br [Departamento de Quimica, Faculdade de Filosofia, Ciencias e Letras de Ribeirao Preto, Universidade de Sao Paulo, CEP 14040-901, Ribeirao Preto, SP (Brazil)

    2010-08-15

    The electrochemical treatment of a synthetic tannery wastewater, prepared with several compounds used by finishing tanneries, was studied in chloride-free media. Boron-doped diamond (Si/BDD), antimony-doped tin dioxide (Ti/SnO{sub 2}-Sb), and iridium-antimony-doped tin dioxide (Ti/SnO{sub 2}-Sb-Ir) were evaluated as anode. The influence of pH and current density on the treatment was assessed by means of the parameters used to measure the level of organic contaminants in the wastewater; i.e., total phenols, chemical oxygen demand (COD), total organic carbon (TOC), and absorbance. Results showed that faster decrease in these parameters occurred when the Si/BDD anode was used. Good results were obtained with the Ti/SnO{sub 2}-Sb anode, but its complete deactivation was reached after 4 h of electrolysis at 25 mA cm{sup -2}, indicating that the service life of this electrode is short. The Ti/SnO{sub 2}-Sb-Ir anode is chemically and electrochemically more stable than the Ti/SnO{sub 2}-Sb anode, but it is not suitable for the electrochemical treatment under the studied conditions. No significant changes were observed for electrolyses performed at different pH conditions with Si/BDD, and this electrode led to almost complete mineralization after 4 h of electrolysis at 100 mA cm{sup -2}. The increase in current density resulted in faster wastewater oxidation, with lower current efficiency and higher energy consumption. Si/BBD proved to be the best electrodic material for the direct electrooxidation of tannery wastewaters.

  16. The initial behaviour of freshly etched copper in modertely acid, aerated chloride solutions

    DEFF Research Database (Denmark)

    Bech-Nielsen, Gregers; Jaskula, M.; Chorkendorff, Ib;

    2002-01-01

    When freshly etched samples of various types of copper were exposed in moderately acid, aerated chloride solutions, two phenomena were observed. First the corrosion potential and the pH of the solution decreased over a shorter time, then the potential increased over a long period (600-1500 min), ...

  17. A convenient catalyst system for microwave accelerated cross-coupling of a range of aryl boronic acids with aryl chlorides

    Directory of Open Access Journals (Sweden)

    Milton Edward J

    2007-05-01

    Full Text Available Abstract A convenient microwave accelerated cross-coupling procedure between aryl chlorides with a range of boronic acids has been developed. An explanation for the low reactivity of highly fluorinated boronic acids in Suzuki coupling is provided.

  18. Humic acids as electron acceptors for anaerobic microbial oxidation of vinyl chloride and dichloroethene

    Science.gov (United States)

    Bradley, P.M.; Chapelle, F.H.; Lovley, D.R.

    1998-01-01

    Anaerobic oxidation of [1,2-14C]vinyl chloride and [1,2- 14C]dichloroethene to 14CO2 under humic acid-reducing conditions was demonstrated. The results indicate that waterborne contaminants can be oxidized by using humic acid compounds as electron acceptors and suggest that natural aquatic systems have a much larger capacity for contaminant oxidation than previously thought.

  19. Preparation of Pure Copper Powder from Acidic Copper Chloride Waste Etchant

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    The method for the recycling of copper from copper chloride solution was developed. This process consists of extraction of copper, purification and particle size reduction. In the first step, reductive metal scraps were added to acidic copper chloride waste enchants produced in the PCB industry to obtain copper powder.Composition analysis showed that this powder contained impurities such as Fe, Ni, and water. So, drying and purification were carried out by using microwave and a centrifugal separator. Thereby the copper powder had a purity of higher than 99% and spherical form in morphology. The copper powder size was decreased by ball milling.

  20. Scientific Opinion on the safety assessment of the active substances iron powder, activated carbon, calcined kaolin, sodium chloride, polyacrylic acid, sodium salt, crosslinked and calcium chloride, for use as active system in food contact materials

    National Research Council Canada - National Science Library

    EFSA Panel on Food Contact Materials, Enzymes, Flavourings and Processing Aids (CEF)

    2014-01-01

    ..., calcined kaolin, sodium chloride, polyacrylic acid, sodium salt, crosslinked and calcium chloride, used in mixture which is packed into labels, for absorbing oxygen from the headspace surrounding packed food...

  1. Current techniques in acid-chloride corrosion control and monitoring at The Geysers

    Energy Technology Data Exchange (ETDEWEB)

    Hirtz, Paul; Buck, Cliff; Kunzman, Russell

    1991-01-01

    Acid chloride corrosion of geothermal well casings, production piping and power plant equipment has resulted in costly corrosion damage, frequent curtailments of power plants and the permanent shut-in of wells in certain areas of The Geysers. Techniques have been developed to mitigate these corrosion problems, allowing continued production of steam from high chloride wells with minimal impact on production and power generation facilities.The optimization of water and caustic steam scrubbing, steam/liquid separation and process fluid chemistry has led to effective and reliable corrosion mitigation systems currently in routine use at The Geysers. When properly operated, these systems can yield steam purities equal to or greater than those encountered in areas of The Geysers where chloride corrosion is not a problem. Developments in corrosion monitoring techniques, steam sampling and analytical methodologies for trace impurities, and computer modeling of the fluid chemistry has been instrumental in the success of this technology.

  2. effect of sowing media and gibberellic acid on the seedling ...

    African Journals Online (AJOL)

    DR. AMIN

    Keywords: Gibberellic Acid, Sowing Media, Bougainvillea glabra, Ixora coccinea, Rosa chinensis ... growth and development and hence concentration and ..... Horticulture. 1st Indian Edition. Biotech Books. Tri -Nagar, New Delhi,. India.

  3. Choline chloride-based deep eutectic solvents as additives for optimizing chromatographic behavior of caffeic acid

    Energy Technology Data Exchange (ETDEWEB)

    Li, Guizhen; Zhu, Tao; Lei, Yingjie [Tianjin University of Technology, Tianjin (China)

    2015-10-15

    A series of deep eutectic solvents (DESs) were prepared using glycerol and choline chloride (ChCl), and Fourier transform infrared spectrometer (FT-IR) was used to analyze the spectra of glycerol, choline chloride and DESs based on glycerol and choline chloride. Then DESs were used as the additives of mobile phase to optimize chromatographic behavior of caffeic acid in high performance liquid chromatography (HPLC). A 17-run Box-Behnken design (BBD) was employed to evaluate effect of DESs as additives by analyzing the maximum theoretical plate number. Three factors, reaction temperature (60 .deg. C, 80 .deg. C, 100 .deg. C), molar ratio of glycerol and choline chloride (2 : 1, 3 : 1, 4 : 1, n/n), and volume percent of additives (0.05%, 0.10%, 0.15%, v/v), were investigated in BBD. The optimum experiment condition was that of reaction temperature (80 .deg. C), molar ratio of glycerol and ChCl (3 : 1, n/n), and volume percent of additive (0.10%, v/v). The mean chromatographic theoretical plate number of the caffeic acid this condition was 1567.5, and DESs as additives shorten the retention time and modify the chromatogram shape, proving DESs as additives for effective theoretical plate number and column efficiency in HPLC.

  4. Stress corrosion cracking of AISI 321 stainless steel in acidic chloride solution

    Indian Academy of Sciences (India)

    Yanliang Huang

    2002-02-01

    The stress corrosion cracking (SCC) of AISI 321 stainless steel in acidic chloride solution was studied by slow strain rate (SSR) technique and fracture mechanics method. The fractured surface was characterized by cleavage fracture. In order to clarify the SCC mechanism, the effects of inhibitor KI on SCC behaviour were also included in this paper. A study showed that the inhibition effects of KI on SCC were mainly attributed to the anodic reaction of the corrosion process. The results of strain distribution in front of the crack tip of the fatigue pre-cracked plate specimens in air, in the blank solution (acidic chloride solution without inhibitor KI) and in the solution added with KI measured by speckle interferometry (SPI) support the unified mechanism of SCC and corrosion fatigue cracking (CFC).

  5. Comparative biocidal activity of peracetic acid, benzalkonium chloride and ortho-phthalaldehyde on 77 bacterial strains.

    Science.gov (United States)

    Bridier, A; Briandet, R; Thomas, V; Dubois-Brissonnet, F

    2011-07-01

    Despite numerous reports on biocide activities, it is often difficult to have a reliable and relevant overview of bacterial resistance to disinfectants because each work challenges a limited number of strains and tested methods are often different. The aim of this study was to evaluate the bactericidal activity of three different disinfectants commonly used in industrial or medical environments (peracetic acid, benzalkonium chloride and ortho-phthalaldehyde) against 77 bacterial strains from different origins using one standard test method (NF EN 1040). Results highlight the existence of high interspecific variability of resistance to disinfectants and, contrary to widespread belief, Gram-positive strains generally appeared more resistant than Gram-negative strains. Resistance was also variable among strains of the same species such as Bacillus subtilis to peracetic acid, Pseudomonas aeruginosa to benzalkonium chloride and Staphylococcus aureus to ortho-phthalaldehyde.

  6. Trans-dichlorodiammineplatinum(II). Acid hydrolysis and the isotopic exchange of the chloride ligands

    Energy Technology Data Exchange (ETDEWEB)

    Martin, Jr., D. S.; Adams, R. J.

    1961-12-31

    The isotopic exchange of chloride ligands of trans-dichlorodiammineplatinum(II) was explored. The rates of isotopic exchange were measured with Cl/sup 36/tracer only in solutions which were at chemical equilibrium. The exchange rate was found to contain a second-order (chloride-dependent) term, in addition to the expected acid hydrolysis term. At Cl/sup -/= 0.l M, the two processes contribute about equally to the exchange. It was also found that k/sub 1/ for t-Pt(NH/sub 3/)sub 2/Cl/sub 2/is larger than for any of the other chloroamine complexes. A summary of the acid hydrolysis equilibrium quotients and rate constants for platinum (II) complexes and other data are tabulated. (P.C.H.)

  7. Photoaffinity Probe Candidates for Gamma-aminobutyric Acid (GABAA)-Gated Chloride Channel

    Institute of Scientific and Technical Information of China (English)

    Shang Zhong LIU; Qing Xiao LI

    2004-01-01

    New photoaffinity ligand candidates were synthesized based on 5-t-butyl-2-(4- (substituted-ethynyl)phenyl)-1, 3-dithiane for the noncompetitive blocker site on the gamma- aminobutyric acid -gated chloride channel. Their half-maximal inhibition concentrations ranged from 4 to 32 nmol/L as measured by 4'-ethynyl-4-n-[2,3-3H2]-propylbicycloorthobenzoate (3H EBOB) assay.

  8. Kinetics of Sawdust Hydrolysis with Dilute Hydrochloric Acid and Ferrous Chloride

    Institute of Scientific and Technical Information of China (English)

    袁传敏; 颜涌捷; 任铮伟; 李庭琛; 曹建勤

    2004-01-01

    With dilute hydrochloric acid as catalyst and promoted by ferrous chloride, hydrolysis of waste sawdust to produce monosaccharides was conducted by using an one-step method in a batch-wise operation reactor. Based on the model of first order consecutive irreversible reactions, the kinetics equation incorporating the term of catalyst concentration was obtained that is suitable for describing the hydrolysis of sawdust. Activation energies were calculated for hydrolysis of sawdust and decomposition of monosaccharides.

  9. Suzuki-Miyaura coupling of heteroaryl boronic acids and vinyl chlorides.

    Science.gov (United States)

    Thakur, Ashish; Zhang, Kainan; Louie, Janis

    2012-01-07

    A protocol for the Suzuki-Miyaura coupling of heteroaryl boronic acids and vinyl chlorides that minimizes protodeboronation is described. A combination of catalytic amounts of Pd(OAc)(2) and SPhos in conjunction with CsF in isopropanol effectively affords a variety of coupled products. Surprisingly, a dramatic temperature dependence in product selectivity was observed. This journal is © The Royal Society of Chemistry 2012

  10. The Effect of Protic Acid Identity on the Structures of Complexes with Vinyl Chloride: Fourier Transform Microwave Spectroscopy and Molecular Structure of the Vinyl Chloride-Hydrogen Chloride Complex

    Science.gov (United States)

    Messinger, Joseph P.; Leung, Helen O.; Marshall, Mark D.

    2014-06-01

    In all previous examples of complexes formed between protic acids and haloethylenes, we have observed similar modes of binding regardless of the specific identity of the acid, HF, HCl, or HCCH. Although details of the structures, such as hydrogen bond length and amount of deviation from linearity, do reflect the strength of the interaction and show clear correlations with the gas-phase acidity, the complexes of a given haloethylene with any of the acids have identical structural motifs. Vinyl chloride, on the other hand, has been observed to adopt different modes of binding in its interactions with HF and HCCH. The HF complex, reported two years ago, has a geometry with HF interacting across the double bond of vinyl chloride and forming a secondary interaction with the hydrogen cis to the chlorine atom, but in the complex with acetylene, reported last year, HCCH locates at one end of the vinyl chloride with the secondary interaction occurring with the geminal hydrogen atom. This variety continues and is expanded in the vinyl chloride-HCl complex. Ab initio theory predicts a complex that has the HCl molecule interacting across the double bond, but located out of the vinyl chloride plane. The microwave spectrum of the most abundant isotopologue of this complex is consistent with theoretical predictions and additionally shows the presence of large amplitude motion connecting two equivalent structures.

  11. Corrosion Behavior of Alloy 22 in Oxalic Acid and Sodium Chloride Solutions

    Energy Technology Data Exchange (ETDEWEB)

    Day, S D; Whalen, M T; King, K J; Hust, G A; Wong, L L; Estill, J C; Rebak, R B

    2003-06-24

    Nickel based Alloy 22 (NO6022) is extensively used in aggressive industrial applications, especially due to its resistance to localized corrosion and stress corrosion cracking in high chloride environments. The purpose of this work was to characterize the anodic behavior of Alloy 22 in oxalic acid solution and to compare its behavior to sodium chloride (NaCl) solutions. Standard electrochemical tests such as polarization resistance and cyclic polarization were used. Results show that the corrosion rate of Alloy 22 in oxalic acid solutions increased rapidly as the temperature and the acid concentration increased. Extrapolation studies show that even at a concentration of 10{sup -4}M oxalic acid, the corrosion rate of Alloy 22 would be higher in oxalic acid than in 1 M NaCl solution. Alloy 22 was not susceptible to localized corrosion in oxalic acid solutions. Cyclic polarization tests in 1 M NaCl showed that Alloy 22 was susceptible to crevice corrosion at 90 C but was not susceptible at 60 C.

  12. Participation of GABAA Chloride Channels in the Anxiolytic-Like Effects of a Fatty Acid Mixture

    Directory of Open Access Journals (Sweden)

    Juan Francisco Rodríguez-Landa

    2013-01-01

    Full Text Available Human amniotic fluid and a mixture of eight fatty acids (FAT-M identified in this maternal fluid (C12:0, lauric acid, 0.9 μg%; C14:0, myristic acid, 6.9 μg%; C16:0, palmitic acid, 35.3 μg%; C16:1, palmitoleic acid, 16.4 μg%; C18:0, stearic acid, 8.5 μg%; C18:1cis, oleic acid, 18.4 μg%; C18:1trans, elaidic acid, 3.5 μg%; C18:2, linoleic acid, 10.1 μg% produce anxiolytic-like effects that are comparable to diazepam in Wistar rats, suggesting the involvement of γ-aminobutyric acid-A (GABAA receptors, a possibility not yet explored. Wistar rats were subjected to the defensive burying test, elevated plus maze, and open field test. In different groups, three GABAA receptor antagonists were administered 30 min before FAT-M administration, including the competitive GABA binding antagonist bicuculline (1 mg/kg, GABAA benzodiazepine antagonist flumazenil (5 mg/kg, and noncompetitive GABAA chloride channel antagonist picrotoxin (1 mg/kg. The FAT-M exerted anxiolytic-like effects in the defensive burying test and elevated plus maze, without affecting locomotor activity in the open field test. The GABAA antagonists alone did not produce significant changes in the behavioral tests. Picrotoxin but not bicuculline or flumazenil blocked the anxiolytic-like effect of the FAT-M. Based on the specific blocking action of picrotoxin on the effects of the FAT-M, we conclude that the FAT-M exerted its anxiolytic-like effects through GABAA receptor chloride channels.

  13. Formation of linear polyenes in poly(vinyl alcohol) films catalyzed by phosphotungstic acid, aluminum chloride, and hydrochloric acid

    Science.gov (United States)

    Tretinnikov, O. N.; Sushko, N. I.; Malyi, A. B.

    2016-07-01

    Formation of linear polyenes-(CH=CH)n-via acid-catalyzed thermal dehydration of polyvinyl alcohol in 9- to 40-µm-thick films of this polymer containing hydrochloric acid, aluminum chloride, and phosphotungstic acid as dehydration catalysts was studied by electronic absorption spectroscopy. The concentration of long-chain ( n ≥ 8) polyenes in films containing phosphotungstic acid is found to monotonically increase with the duration of thermal treatment of films, although the kinetics of this process is independent of film thickness. In films containing hydrochloric acid and aluminum chloride, the formation rate of polyenes with n ≥ 8 rapidly drops as film thickness decreases and the annealing time increases. As a result, at a film thickness of less than 10-12 µm, long-chain polyenes are not formed at all in these films no matter how long thermal duration is. The reason for this behavior is that hydrochloric acid catalyzing polymer dehydration in these films evaporates from the films during thermal treatment, the evaporation rate inversely depending on film thickness.

  14. Protection of copper surface with phytic acid against corrosion in chloride solution.

    Science.gov (United States)

    Peca, Dunja; Pihlar, Boris; Ingrid, Milošev

    2014-01-01

    Phytic acid (inositol hexaphosphate) was tested as a corrosion inhibitor for copper in 3% sodium chloride. Phytic acid is a natural compound derived from plants, it is not toxic and can be considered as a green inhibitor. Electrochemical methods of linear polarization and potentiodynamic polarization were used to study the electrochemical behaviour and evaluate the inhibition effectiveness. To obtain the optimal corrosion protection the following experimental conditions were investigated: effect of surface pre-treatment (abrasion and three procedures of surface roughening), pre-formation of the layer of phytic acid, time of immersion and concentration of phytic acid. To evaluate the surface pre-treatment procedures the surface roughness and contact angle were measured. Optimal conditions for formation of phytic layer were selected resulting in the inhibition effectiveness of nearly 80%. Morphology and composition of the layer were further studied by scanning electron microscopy, energy dispersive X-ray spectroscopy and X-ray photoelectron spectroscopy. The layer of phytic acid with thickness in the nanometer range homogeneously covers the copper surface. The obtained results show that this natural compound can be used as a mildly effective corrosion inhibitor for copper in chloride solution.

  15. Metal lanolin fatty acid as novel thermal stabilizers for rigid poly(vinyl chloride)

    Institute of Scientific and Technical Information of China (English)

    GUO Yong; ZHENG Yuying; QIU Shangchang; ZENG Anran; LI Baoming

    2011-01-01

    The synergistic stabilization effect of different metal lanolin fatty acids as natural-based thermal stabilizers for poly(vinyl chloride)(PVC) including calcium lanolin fatty acid (Calan2), zinc lanolin fatty acid (Znlan2) and lanthanum lanolin fatty acid (Lalan3) were studied through Congo red testing, color measurements, FTIR analyses and thermal behavior in this paper. The results showed that Lalan3/Calan2/Znlan2 stabilizers exhibited more excellent thermal stabilization efficiency to PVC than Calan2/Znlan2 thermal stabilizers, and the optimal mass ratio of Lalan3/Calan2/Znlan2 was 8:9:3. At last, the effect of degradation mechanism on PVC and synergistic stabilization was also investigated by FTIR analyses and thermal behavior.

  16. Efficient acetylation of primary amines and amino acids in environmentally benign brine solution using acetyl chloride

    Indian Academy of Sciences (India)

    Kaushik Basu; Suchandra Chakraborty; Achintya Kumar Sarkar; Chandan Saha

    2013-05-01

    Acetyl chloride is one of the most commonly available and cheap acylating agent but its high reactivity and concomitant instability in water precludes its use to carry out acetylation in aqueous medium. The present methodology illustrates the efficient acetylation of primary amines and amino acids in brine solution by means of acetyl chloride under weakly basic condition in the presence of sodium acetate and/or triethyl amine followed by trituration with aqueous saturated bicarbonate solution. This effort represents the first efficient use of this most reactive but cheap acetylating agent to acetylate amines in excellent yields in aqueous medium. This is a potentially useful green chemical transformation where reaction takes place in environment-friendly brine solution leading to easy work-up and isolation of the amide derivatives. Mechanistic rationale of this methodology is also important.

  17. Studies on the electrodeposition of tin from acidic chloride-gluconate solutions

    Science.gov (United States)

    Rudnik, Ewa; Włoch, Grzegorz

    2013-01-01

    Electrodeposition of tin from acidic chloride-gluconate baths was investigated. Equilibrium distribution of tin(II) species showed domination of Sn(II)-gluconate complexes, but for Sn2+ concentrations 50 mM or higher increased percentage of Sn(II)-chloride complexes was found. Cyclic voltammetry, anodic stripping analysis and potentiostatic measurements indicated that rate of the cathodic process is determined by the release of metal cations from gluconate complexes in diluted bath (5 mM), but for more concentrated solutions reduction of Sn(II) ions run under diffusion control. Studies of anodic response showed that it depends on the Sn(II)/Glu ratio in the bath and deposition potential due to development of different planes of metal crystal. Average effective diffusion coefficients of metal species were determined. Morphology and structure tin deposits were also presented.

  18. Immobilization of fission products arising from pyrometallurgical reprocessing in chloride media

    Science.gov (United States)

    Leturcq, G.; Grandjean, A.; Rigaud, D.; Perouty, P.; Charlot, M.

    2005-12-01

    Spent nuclear fuel reprocessing to recover energy-producing elements such as uranium or plutonium can be performed by a pyrochemical process. In such method, the actinides and fission products are extracted by electrodeposition in a molten chloride medium. These processes generate chlorinated alkali salt flows contaminated by fission products, mainly Cs, Ba, Sr and rare earth elements constituting high-level waste. Two possible alternatives are investigated for managing this wasteform; a protocol is described for dechlorinating the fission products to allow vitrification, and mineral phases capable of immobilizing chlorides are listed to allow specification of a dedicated ceramic matrix suitable for containment of these chlorinated waste streams. The results of tests to synthesize chlorosilicate phases are also discussed.

  19. The central role of chloride in the metabolic acid-base changes in canine parvoviral enteritis.

    Science.gov (United States)

    Burchell, Richard K; Schoeman, Johan P; Leisewitz, Andrew L

    2014-04-01

    The acid-base disturbances in canine parvoviral (CPV) enteritis are not well described. In addition, the mechanisms causing these perturbations have not been fully elucidated. The purpose of the present study was to assess acid-base changes in puppies suffering from CPV enteritis, using a modified strong ion model (SIM). The hypothesis of the study was that severe acid-base disturbances would be present and that the SIM would provide insights into pathological mechanisms, which have not been fully appreciated by the Henderson-Hasselbalch model. The study analysed retrospective data, obtained from 42 puppies with confirmed CPV enteritis and 10 healthy control dogs. The CPV-enteritis group had been allocated a clinical score, to allow classification of the data according to clinical severity. The effects of changes in free water, chloride, l-lactate, albumin and phosphate were calculated, using a modification of the base excess algorithm. When the data were summated for each patient, and correlated to each individual component, the most important contributor to the metabolic acid-base changes, according to the SIM, was chloride (Penteritis are multifactorial and complex, with the SIM providing information in terms of the origin of these changes.

  20. Inactivation of human norovirus surrogates by benzalkonium chloride, potassium peroxymonosulfate, tannic acid, and gallic acid.

    Science.gov (United States)

    Su, Xiaowei; D'Souza, Doris H

    2012-09-01

    Novel methods to effectively disinfect contact surfaces and prevent human norovirus transmission are essential. The effect of benzalkonium chloride (BAC), potassium peroxymonosulfate (KPMS), tannic acid (TA), and gallic acid (GA) on enteric virus surrogates, murine norovirus (MNV-1), feline calicivirus (FCV-F9), and bacteriophage MS2 was studied. Viruses at high (∼7 log₁₀ PFU/mL) or low (∼5 log₁₀ PFU/mL) titers were mixed with equal volumes of BAC (0.2, 0.5, and 1 mg/mL), KPMS (5, 10, and 20 mg/mL), TA (0.02 and 0.2 mg/mL), GA (0.2, 0.4, and 0.8 mg/mL), or water and incubated for 2 h at room temperature. Viral infectivity after triplicate treatments was evaluated using plaque assays in duplicate. Low titers of FCV-F9 and MNV-1 were completely reduced, while low-titer MS2 was reduced by 1.7-1.8 log₁₀ PFU/mL with BAC at all three concentrations. High-titer FCV-F9 was reduced by 2.87, 3.08, and 3.25 log₁₀ PFU/mL, and high-titer MNV-1 was reduced by 1.55, 2.32, and 2.75 log₁₀ PFU/mL with BAC at 0.1, 0.25, and 0.5 mg/mL, respectively. High-titer MS2 was reduced by ∼2 log₁₀ PFU/mL with BAC at all three concentrations. KPMS at all three concentrations reduced high and low titers of FCV-F9 and MS2 and low-titer MNV-1 to undetectable levels, while high-titer MNV-1 was reduced by 0.92 and 3.44 log₁₀ PFU/mL with KMPS at 2.5 and 5 mg/mL, respectively. TA at 0.2 mg/mL only reduced high-titer FCV-F9 by 0.98 log₁₀ PFU/mL and low-titer FCV-F9 by 1.95 log₁₀ PFU/mL. GA at 0.1, 0.2, and 0.4 mg/mL reduced low-titer FCV-F9 by 2.50, 2.36, and 0.86 log₁₀ PFU/mL, respectively with negligible effects against high-titer FCV-F9. BAC and KPMS show promise to be used as broad-spectrum contact surface disinfectants for prevention of noroviral surrogate contamination.

  1. Functional modifications of acid-sensing ion channels by ligand-gated chloride channels.

    Directory of Open Access Journals (Sweden)

    Xuanmao Chen

    Full Text Available Together, acid-sensing ion channels (ASICs and epithelial sodium channels (ENaC constitute the majority of voltage-independent sodium channels in mammals. ENaC is regulated by a chloride channel, the cystic fibrosis transmembrane conductance regulator (CFTR. Here we show that ASICs were reversibly inhibited by activation of GABA(A receptors in murine hippocampal neurons. This inhibition of ASICs required opening of the chloride channels but occurred with both outward and inward GABA(A receptor-mediated currents. Moreover, activation of the GABA(A receptors modified the pharmacological features and kinetic properties of the ASIC currents, including the time course of activation, desensitization and deactivation. Modification of ASICs by open GABA(A receptors was also observed in both nucleated patches and outside-out patches excised from hippocampal neurons. Interestingly, ASICs and GABA(A receptors interacted to regulate synaptic plasticity in CA1 hippocampal slices. The activation of glycine receptors, which are similar to GABA(A receptors, also modified ASICs in spinal neurons. We conclude that GABA(A receptors and glycine receptors modify ASICs in neurons through mechanisms that require the opening of chloride channels.

  2. Specific acid catalysis and Lewis acid catalysis of Diels–Alder reactions in aqueous media

    NARCIS (Netherlands)

    Mubofu, Egid B.; Engberts, Jan B.F.N.

    2004-01-01

    A comparative study of specific acid catalysis and Lewis acid catalysis of Diels–Alder reactions between dienophiles (1, 4 and 6) and cyclopentadiene (2) in water and mixed aqueous media is reported. The reactions were performed in water with copper(II) nitrate as the Lewis acid catalyst whereas

  3. Specific acid catalysis and Lewis acid catalysis of Diels-Alder reactions in aqueous media

    NARCIS (Netherlands)

    Mubofu, E.B.; Engberts, J.B.F.N.

    A comparative study of specific acid catalysis and Lewis acid catalysis of Diells-Alder reactions between dienophiles (1, 4 and 6) and cyclopentadiene (2) in water and mixed aqueous media is reported. The reactions were performed in water with copper(II) nitrate as the Lewis acid catalyst whereas

  4. Specific acid catalysis and Lewis acid catalysis of Diels-Alder reactions in aqueous media

    NARCIS (Netherlands)

    Mubofu, E.B.; Engberts, J.B.F.N.

    2004-01-01

    A comparative study of specific acid catalysis and Lewis acid catalysis of Diells-Alder reactions between dienophiles (1, 4 and 6) and cyclopentadiene (2) in water and mixed aqueous media is reported. The reactions were performed in water with copper(II) nitrate as the Lewis acid catalyst whereas hy

  5. Specific acid catalysis and Lewis acid catalysis of Diels–Alder reactions in aqueous media

    NARCIS (Netherlands)

    Mubofu, Egid B.; Engberts, Jan B.F.N.

    2004-01-01

    A comparative study of specific acid catalysis and Lewis acid catalysis of Diels–Alder reactions between dienophiles (1, 4 and 6) and cyclopentadiene (2) in water and mixed aqueous media is reported. The reactions were performed in water with copper(II) nitrate as the Lewis acid catalyst whereas hyd

  6. The coulometric titration of acids and bases in dimethylsulfoxide media

    NARCIS (Netherlands)

    Bos, M.; IJpma, S.T.; Dahmen, E.A.M.F.

    1976-01-01

    The coulometric titration of 20–200 μeq of acids and bases in DMSO media is described. In the titration of bases, the electro-oxidation of hydrogen at a platinized platinum electrode is used as the source of protons. The conditions for 100 % current efficiency at this electrode are low current

  7. Heterogeneous reactions of epoxides in acidic media.

    Science.gov (United States)

    Lal, Vinita; Khalizov, Alexei F; Lin, Yun; Galvan, Maria D; Connell, Brian T; Zhang, Renyi

    2012-06-21

    Epoxides have recently been identified as important intermediates in the gas phase oxidation of hydrocarbons, and their hydrolysis products have been observed in ambient aerosols. To evaluate the role of epoxides in the formation of secondary organic aerosols (SOA), the kinetics and mechanism of heterogeneous reactions of two model epoxides, isoprene oxide and α-pinene oxide, with sulfuric acid, ammonium bisulfate, and ammonium sulfate have been investigated using complementary experimental techniques. Kinetic experiments using a fast flow reactor coupled to an ion drift-chemical ionization mass spectrometer (ID-CIMS) show a fast irreversible loss of the epoxides with the uptake coefficients (γ) of (1.7 ± 0.1) × 10(-2) and (4.6 ± 0.3) × 10(-2) for isoprene oxide and α-pinene oxide, respectively, for 90 wt % H(2)SO(4) and at room temperature. Experiments using attenuated total reflection-Fourier transform infrared spectroscopy (ATR-FTIR) reveal that diols are the major products in ammonium bisulfate and dilute H(2)SO(4) (65 wt %), acetals are formed from isoprene oxide, whereas organosulfates are produced from α-pinene oxide. The reaction of the epoxides with ammonium sulfate is slow and no products are observed. The epoxide reactions using bulk samples and Nuclear Magnetic Resonance (NMR) spectroscopy reveal the presence of diols as the major products for isoprene oxide, accompanied by aldehyde formation. For α-pinene oxide, organosulfate formation is observed with a yield increasing with the acidity. Large yields of organosulfates in all NMR experiments with α-pinene oxide are attributed to the kinetic isotope effect (KIE) from the use of deuterated sulfuric acid and water. Our results suggest that acid-catalyzed hydrolysis of epoxides results in the formation of a wide range of products, and some of the products have low volatility and contribute to SOA growth under ambient conditions prevailing in the urban atmosphere.

  8. Photochemical oxidation of chloride ion by ozone in acid aqueous solution.

    Science.gov (United States)

    Levanov, Alexander V; Isaykina, Oksana Ya; Amirova, Nazrin K; Antipenko, Ewald E; Lunin, Valerii V

    2015-11-01

    The experimental investigation of chloride ion oxidation under the action of ozone and ultraviolet radiation with wavelength 254 nm in the bulk of acid aqueous solution at pH 0-2 has been performed. Processes of chloride oxidation in these conditions are the same as the chemical reactions in the system O3 - OH - Cl(-)(aq). Despite its importance in the environment and for ozone-based water treatment, this reaction system has not been previously investigated in the bulk solution. The end products are chlorate ion ClO3(-) and molecular chlorine Cl2. The ions of trivalent iron have been shown to be catalysts of Cl(-) oxidation. The dependencies of the products formation rates on the concentrations of O3 and H(+) have been studied. The chemical mechanism of Cl(-) oxidation and Cl2 emission and ClO3(-) formation has been proposed. According to the mechanism, the dominant primary process of chloride oxidation represents the complex interaction with hydroxyl radical OH with the formation of Cl2(-) anion-radical intermediate. OH radical is generated on ozone photolysis in aqueous solution. The key subsequent processes are the reactions Cl2(-) + O3 → ClO + O2 + Cl(-) and ClO + H2O2 → HOCl + HO2. Until the present time, they have not been taken into consideration on mechanistic description and modelling of Cl(-) oxidation. The final products are formed via the reactions 2ClO → Cl2O2, Cl2O2 + H2O → 2H(+) + Cl(-) + ClO3(-) and HOCl + H(+) + Cl(-) ⇄ H2O + Cl2. Some portion of chloride is oxidized directly by O3 molecule with the formation of molecular chlorine in the end.

  9. Pre-harvest foliar application of humic acid, salicylic acid and calcium chloride to increase quantitative and qualitative traits of Lilium longiflorum cut flowers

    Directory of Open Access Journals (Sweden)

    S.N. Mortazavi

    2015-11-01

    Full Text Available Lily (Lilium longiflorum L. is one of the most important potted flowers, which is used largely as cut flower. An experiment, arranged as a factorial besed on completely randomized dasign with three replications, was carried out to evaluate the effects of pre-harvest foliar application of humic acid, salicylic acid and calcium chloride on quality and longevity of lilium cut flowers. Treatments  included humic acid as factor a (0, 100, 500 and 1000 mg/L and three salicylic acid concentrations (0, 150 and 200 mg/L and two calcium chloride concentrations (300 and 600 mg/L as factor b, which were sprayed at two stages before harvesting the flowers. Results showed that treating the plants with 500 mg/L humic acid increased water uptake and chlorophyll a content and decreased number of fallen florets. Application of 1000 mg/L humic acid increased total chlorophyll content. Pre-harvest treatment of flowers with 600 mg/L calcium chloride increased florets’ diameter, relative water content, chlorophyll b content and shelf life, as compared to other concentrations and different salicylic concentrations. In this research, the highest shelf life was observed for flowers sprayed with 1000 mg/L humic acid and 300 mg/L calcium chloride. Therefore, pre-harvest foliar application of humic acid, salicylic acid and calcium chloride could have positive effects on quantitative and qualitative traits of lilium cut flowers.

  10. Involvements of chloride ion in decolorization of Acid Orange 7 by activated peroxydisulfate or peroxymonosulfate oxidation

    Institute of Scientific and Technical Information of China (English)

    Ping Wang; Shiying Yang; Liang Shan; Rui Niu; Xueting Shao

    2011-01-01

    The effects of chloride anion (C1-) (up to 1.0 mol/L) on the decolorization of a model compound,azo dye Acid Orange 7 (AO7),by sulfate radical (SO4-*) based-peroxydisulfate (PS) or peroxymonosulfate (PMS) oxidation under various activated conditions (UV254 nm/PS,Thermal (70℃/PS,UV254 nm/PMS,Co2+/PMS) were investigated.Methanol and NH4+ were used as quenching reagents to determine the contributions of active chlorine species (dichloride radical (Cl2-*) and hypochlorous acid (HClO)).The results indicated that the effects of Cl- on the reaction mechanism were different under various activated conditions.For UV/PS and Thermal/PS,the inhibition tendency became more clear as the Cl-concentration increased,probably due to the reaction between Cl- and SO4-* and the generation of Cl2-* or HClO.For UV/PMS,Cl- did not exhibit inhibition when the concentration was below 0.1 mol/L.As Cl-concentration reached to 1.0 mol/L,the decolorization rate of AO7 was,however,accelerated,possibly because PMS directly reacts with C1- to form HC1O.For Co2+/PMS,Cl- exhibited a significant inhibiting effect even at low concentration (≤ 0.01 mol/L).When Cl- concentration exceeded 0.1 mol/L,the activation of PMS by Co2+ was almost completely inhibited.Under this condition,HClO maybe played a major role in decolorization of AO7.The results implicated that chloride ion is an important factor in SO4-*-based degradation of organic contamination in chloride-containing water.

  11. Combined effects of lanthanum (III) chloride and acid rain on photosynthetic parameters in rice.

    Science.gov (United States)

    Wang, Lihong; Wang, Wen; Zhou, Qing; Huang, Xiaohua

    2014-10-01

    Rare earth elements (REEs) pollution and acid rain are environmental issues, and their deleterious effects on plants attract worldwide attention. These two issues exist simultaneously in many regions, especially in some rice-growing areas. However, little is known about the combined effects of REEs and acid rain on plants. Here, the combined effects of lanthanum chloride (LaCl3), one type of REE salt, and acid rain on photosynthesis in rice were investigated. We showed that the combined treatment of 81.6 μM LaCl3 and acid rain at pH 4.5 increased net photosynthetic rate (Pn), stomatic conductance (Gs), intercellular CO2 concentration (Ci), Hill reaction activity (HRA), apparent quantum yield (AQY) and carboxylation efficiency (CE) in rice. The combined treatment of 81.6 μM LaCl3 and acid rain at pH 3.5 began to behave toxic effects on photosynthesis (decreasing Pn, Gs, HRA, AQY and CE, and increasing Ci), and the maximally toxic effects were observed in the combined treatment of 2449.0 μM LaCl3 and acid rain at pH 2.5. Moreover, the combined effects of LaCl3 and acid rain on photosynthesis in rice depended on the growth stage of rice, with the maximal effects occurring at the booting stage. Furthermore, the combined treatment of high-concentration LaCl3 and low-pH acid rain had more serious effects on photosynthesis in rice than LaCl3 or acid rain treatment alone. Finally, the combined effect of LaCl3 and acid rain on Pn in rice resulted from the changes in stomatic (Gs, Ci) and non-stomatic (HRA, AQY and CE) factors.

  12. Leaching platinum-group metals in a sulfuric acid/chloride solution

    Science.gov (United States)

    Mahmoud, M. H. H.

    2003-04-01

    A leaching process was established based on the ability of platinum-group metals to form stable chloro-complexes in acidic chloride solutions. Industrial catalyst losses were examined for the recovery of platinum, palladium, and rhodium by leaching with a mixture of sulfuric acid and sodium chloride to avoid using aqua regia or autoclave conditions. Extraction of platinum and rhodium in 60% H2SO4 at 135°C steadily increased with increasing NaCl concentrations reaching 95% and 85%, respectively, at 0.1 M NaCl after two hours. By comparison, palladium was dissolved more quickly but also reached 85% under the same conditions. Extraction of each metal increased with temperatures up to 125°C but plateaued at higher temperatures. Similar behavior was observed with increasing H2SO4 concentrations up to 60%. More than 99% extraction of each metal was obtained after ten hours using 0.1 M NaCl and 60% H2SO4 at 125°C.

  13. Hydrazino-methoxy-1,3,5-triazine Derivatives' Excellent Corrosion Organic Inhibitors of Steel in Acidic Chloride Solution.

    Science.gov (United States)

    El-Faham, Ayman; Osman, Sameh M; Al-Lohedan, Hamad A; El-Mahdy, Gamal A

    2016-06-01

    The corrosion inhibition performance of 2-hydrazino-4,6-dimethoxy-1,3,5-tirazine (DMeHT), 2,4-dihydrazino-6-methoxy-1,3,5-triaizine (DHMeT), and 2,4,6-tridydrazino-1,3,5-triaizne (TH₃) on steel corrosion in acidic media was examined using electrochemical techniques. The results showed 2,4-Ddihydrazino-6-methoxy-1,3,5-triaizine (DHMeT) gave the best corrosion protection performance among the other hydrazino derivatives even at a low concentration of 25 ppm (95%). The number of hydrazino groups play an important role in the corrosion inhibition, where the two hydrazine groups increased the electrostatic interactions between the protonated tested compounds, the negatively charged steel surface resulted from the adsorption of the chloride anions, and the presence of the methoxy group made the compound more reliable for formation of film protection on the surface of steel through the lone pair of oxygen atoms. Electrochemical Impedance Spectroscopy (EIS) measurements suggested that the corrosion process of steel in presence of the hydrazino-s-triazine derivatives (TH₃, DMeHT and DHMeT) were being controlled by the charge transfer reaction. Polarization curves indicated that the examined TH₃, DMeHT and DHMeT behaved as mixed type inhibitors.

  14. Hydrazino-methoxy-1,3,5-triazine Derivatives’ Excellent Corrosion Organic Inhibitors of Steel in Acidic Chloride Solution

    Directory of Open Access Journals (Sweden)

    Ayman El-Faham

    2016-06-01

    Full Text Available The corrosion inhibition performance of 2-hydrazino-4,6-dimethoxy-1,3,5-tirazine (DMeHT, 2,4-dihydrazino-6-methoxy-1,3,5-triaizine (DHMeT, and 2,4,6-tridydrazino-1,3,5-triaizne (TH3 on steel corrosion in acidic media was examined using electrochemical techniques. The results showed 2,4-Ddihydrazino-6-methoxy-1,3,5-triaizine (DHMeT gave the best corrosion protection performance among the other hydrazino derivatives even at a low concentration of 25 ppm (95%. The number of hydrazino groups play an important role in the corrosion inhibition, where the two hydrazine groups increased the electrostatic interactions between the protonated tested compounds, the negatively charged steel surface resulted from the adsorption of the chloride anions, and the presence of the methoxy group made the compound more reliable for formation of film protection on the surface of steel through the lone pair of oxygen atoms. Electrochemical Impedance Spectroscopy (EIS measurements suggested that the corrosion process of steel in presence of the hydrazino-s-triazine derivatives (TH3, DMeHT and DHMeT were being controlled by the charge transfer reaction. Polarization curves indicated that the examined TH3, DMeHT and DHMeT behaved as mixed type inhibitors.

  15. Localized corrosion of LY12CZ under stress in chloride media

    Institute of Scientific and Technical Information of China (English)

    RAO Si-xian; ZHANG Zheng; ZHU Li-qun; ZHONG Qun-peng

    2006-01-01

    Electrochemical methods were applied to investigate the corrosion behaviour of LY12CZ under applied stress in 3% sodium chloride aqueous solution. The experimental results indicate that LY12CZ shows two breakdown potentials on its polarization curve: one is related to the dissolution of the intermetallic particles and the other is related to the cracking of oxidation film and the dissolution of the matrix. When the stress is applied, it varies both breakdown potentials and makes the intermetallic particles and matrix dissolute at lower potentials. The relationship between the variation of the two breakdown potentials and applied stress was summarized. At the same time the influence of stress on the pitting and intergranular corrosion sensitivity of LY12CZ was also investigated. From the results it can be concluded that the stress can significantly affect the localized corrosion behaviour of LY12CZ in 3% NaCl solution.

  16. The dissolution of chalcopyrite in chloride media; Lixiviacion de la calcopirita en medios clorurados

    Energy Technology Data Exchange (ETDEWEB)

    Ibanez, T.; Velasquez, L.

    2013-06-01

    The aim of this investigation is to determinate the effects of parameters and additives on the kinetics of dissolution of chalcopyrite on moderated conditions by means of dissolutions test with chalcopyrite concentrate and pure chalcopyrite in shake flasks and instrumented stirred reactors. A study of the dissolution of chalcopyrite in chloride solutions has demonstrated that the rate of dissolution of chalcopyrite is strongly dependent on the potential of the solution within a range of 540 to 630 mV (versus SHE). Leaching at pH around 2.5 results in increased rates of copper dissolution suggesting the possibility to keep the solution potential within the range. Both pyrite and silver ions enhance the dissolution of chalcopyrite and this effect increases when both species are present. The MnO{sub 2} has a negative effect on the dissolution increasing the solution potential to values where the rate decreases considerably. (Author)

  17. SYNTESIS OF THE COMPLEXES OF MACROPOROUS SULFONATED RESINS WITH FERRIC CHLORIDE AND THEIR CATALYTIC BEHAVIOR FOR SETERIFICATION OF ACETIC ACID WITH BUTANOL

    Institute of Scientific and Technical Information of China (English)

    HuangWenqiang; HouXin; 等

    1997-01-01

    The complex resins prepared from macroporous sulfonated resin D72(H+ form) with ferric chloride or ferric chloride hexahydrate have both sites of Bronsted acid and Lewis acid.In the catalysis of exterification of acetic acid with butanol the complex resins show to have much higher catalytic activity than that of its matrix.a conventional sulfonated cation exchange resin D72.

  18. Antifungal activity of essential oils when associated with sodium chloride or fatty acids

    Directory of Open Access Journals (Sweden)

    Tantatoui-Elaraki, Abdelthafour

    1994-12-01

    Full Text Available The inhibition of mycelium growth in a Zygorhynchus sp. and an Aspergillus niger isolates was studied. The inhibition rates (IR caused by 4 essential oils (EO, 5 fatty acids and sodium chloride at various concentrations were determined in Sabouraud Dextrose Agar.
    A synergy of action was observed between sodium chloride at 7.5% and the EO of thyme (0.04%, camomile (0.4% and mugwort (0.2 and 0.1% on A. niger and between sodium chloride (5% and the EO of camomile (0.1% and mugwort (0.1 and 0.01% and sodium chloride (7.5% and eucalyptus EO (0.4 and 0.2% on Zygorhynchus sp.
    Camomile EO (0.13% associated with propionic acid (0.075%, lauric acid (0.05% or oleic acid (0.15% led to synergetic effect on Zygorhynchus sp. as well as thyme EO (0.04 and 0.05%, respectively with propionic acid (0.1% and linolenic acid (0.075% on A. niger. Other combinations exerted no higher effects than each of the substances used alone.
    Practical applications of the results observed were discussed

    Se ha estudiado la inhibición del crecimiento miceliar en un aislamiento de Zygorhynchus sp. y otro de Aspergillus niger. Se determinaron las tasas (o índices de inhibición (IR en Agar Sabouraud Dextrosa provocados por varias concentraciones de 4 aceites esenciales (EG, 5 ácidos grasos y cloruro sódico.
    Se observó un efecto sinérgico entre cloruro sódico al 7.5% y los aceites esenciales de tomillo (0.04%, manzanilla (0.4% y artemisa (0.2 y 0.1% sobre A. niger, y entre cloruro sódico (5% y los aceites esenciales de manzanilla (0.1% y de artemisa (0.1 y 0.01%, así como cloruro sódico (7.5% y aceite esencial de eucalipto (0.4 y 0.2%, sobre Zygorhynchus sp.
    El aceite esencial de manzanilla (0.13% en asociación con ácido propiónico (0.075%, ácido láurico (0.05% o ácido oleico (0.15% provocó un efecto sinérgico sobre Zygorhynchus sp., de la misma forma

  19. Kinetics and mechanism of the reaction of gold(III chloride complexes with formic acid

    Directory of Open Access Journals (Sweden)

    Pacławski K.

    2015-01-01

    Full Text Available In this work, the results of kinetic studies of the redox reaction of gold(III chloride complexes ([AuCl4]- with formic acid, are presented. Obtained data suggest the complex character of the reaction which leads to the [AuCl2]- and [AuCl3(COOH]- ions formation as intermediates. In the pH range over 2.5, the final product of the reaction is metallic gold. From the analysis of kinetic data, the rate limiting step is found to be the gold metallic phase formation. The stage of Au(III reduction is relatively fast with the second-order rate constant equal to 61.8 M-1s-1 at temperature 50ºC. The rate of the studied reaction depends on the temperature, reactants concentration and chloride ions concentration. As a result of the data analysis, the scheme of the reaction path has been suggested. Also, the values of enthalpy and entropy of activation for the reaction have been determined.

  20. Reactive extraction of lactic acid with trioctylamine/methylene chloride/n-hexane

    Energy Technology Data Exchange (ETDEWEB)

    Han, D.H.; Hong, W.H. [Korea Advanced Inst. of Science and Technology, Tajeon (Korea, Democratic People`s Republic of)

    1996-04-01

    The trioctylamine (TOA)/methylene chloride (MC)/n-hexane system was used as the extraction agent for the extraction of lactic acid. Curves of equilibrium and hydration were obtained at various temperatures and concentrations of TOA. A modified mass action model was proposed to interpret the equilibrium and the hydration curves. The reaction mechanism and the corresponding parameters which best represent the equilibrium data were estimated, and the concentration of water in the organic phase was predicted by inserting the parameters into the simple mathematical equation of the modified model. The concentration of MC and the change of temperature were important factors for the extraction and the stripping process. The stripping was performed by a simple distillation which was a combination of temperature-swing regeneration and diluent-swing regeneration. The type of inactive diluent has no influence on the stripping. The stripping efficiencies were about 70%.

  1. Radiation-induced grafting of diallyldimethylammonium chloride onto acrylic acid grafted polyethylene

    Science.gov (United States)

    Francis, Sanju; Dhanawade, B. R.; Mitra, D.; Varshney, Lalit; Sabharwal, Sunil

    2009-01-01

    Diallyldimethylammonium chloride (DADMAC) was grafted onto polyethylene (PE) films by a double grafting procedure. The PE film was initially modified by grafting acrylic acid (AA), through a mutual irradiation method. AA-g-PE film, thus obtained was subjected to subsequent radiation grafting reaction of DADMAC, to give a DADMAC-g-AA-g-PE film having a comb-type structure. The influence of different conditions, such as the extent of AA grafting, DADMAC concentration, absorbed dose and dose rate, on the grafting yield of DADMAC was investigated. A maximum DADMAC grafting of 30% was achieved. The equilibrium degree of swelling (EDS) of the grafted films were gravimetrically determined. TGA and FT-IR techniques were employed to characterize the grafted PE films.

  2. Radiation-induced grafting of diallyldimethylammonium chloride onto acrylic acid grafted polyethylene

    Energy Technology Data Exchange (ETDEWEB)

    Francis, Sanju [Radiation Technology Development Section, Bhabha Atomic Research Centre, Trombay, Mumbai 400 085 (India)], E-mail: sanju@barc.gov.in; Dhanawade, B.R.; Mitra, D.; Varshney, Lalit; Sabharwal, Sunil [Radiation Technology Development Section, Bhabha Atomic Research Centre, Trombay, Mumbai 400 085 (India)

    2009-01-15

    Diallyldimethylammonium chloride (DADMAC) was grafted onto polyethylene (PE) films by a double grafting procedure. The PE film was initially modified by grafting acrylic acid (AA), through a mutual irradiation method. AA-g-PE film, thus obtained was subjected to subsequent radiation grafting reaction of DADMAC, to give a DADMAC-g-AA-g-PE film having a comb-type structure. The influence of different conditions, such as the extent of AA grafting, DADMAC concentration, absorbed dose and dose rate, on the grafting yield of DADMAC was investigated. A maximum DADMAC grafting of 30% was achieved. The equilibrium degree of swelling (EDS) of the grafted films were gravimetrically determined. TGA and FT-IR techniques were employed to characterize the grafted PE films.

  3. Hydrochloric acid recovery from rare earth chloride solutions by vacuum membrane distillation

    Institute of Scientific and Technical Information of China (English)

    TANG Jianjun; ZHOU Kanggen

    2006-01-01

    The possibility of the recovery of hydrochloric acid from rare earth (RE) chloride solutions was first experimentally studied by batch vacuum membrane distillation (VMD). The recovery by continuous VMD was also studied to devise methods that enabled the operation of VMD setup in a stable condition as well as to increase the membrane-operating life The results indicated that HCl separation with RE by VMD was possible, and the recovery ratio of 80% could be achieved by batch VMD. In continuous VMD, when the temperature of circular solutions, circular rate, and downstream pressure was62-63℃, 5.4 cm/s, and 9.33 kPa, respectively, the HCl concentration in circular solutions and the processing capacity per membrane area were obtained. The mathematical results were in accordance with the experimental ones.

  4. A role for sodium and chloride in kainic acid-induced beading of inhibitory interneuron dendrites.

    Science.gov (United States)

    Al-Noori, S; Swann, J W

    2000-01-01

    Excitotoxic injury of the dendrites of inhibitory interneurons could lead to decreases in their synaptic activation and explain subsequent local circuit hyperexcitability and epilepsy. A hallmark of dendrotoxicity, at least in principal neurons of the hippocampus and cortex, is focal or varicose swellings of dendritic arbors. In experiments reported here, transient (1h) exposure of hippocampal explant cultures to kainic acid produced marked focal swellings of the dendrites of parvalbumin-immunoreactive pyramidal basket cells in a highly reproducible and dose-dependent manner. At 5mM kainic acid, more than half of the immunopositive apical dendrites in area CA(1) had a beaded appearance. However, the somal volumes of these cells were unaltered by the same treatment. The presence of focal swellings was reversible with kainate washout and was not accompanied by interneuronal cell death. In contrast, exposure to much higher concentrations (300mM) of kainic acid resulted in the total loss of parvalbumin-positive interneurons from explants. Surprisingly, kainic acid-induced dendritic beading does not appear to be mediated by extracellular calcium. Beading was unaltered in the presence of N-methyl-D-aspartate receptor antagonists, the L-type calcium channel antagonist, nimodipine, cadmium, or by removing extracellular calcium. However, blockade of voltage-gated sodium channels by either tetrodotoxin or lidocaine abolished dendritic beading, while the activation of existing voltage-gated sodium channels by veratridine mimicked the kainic acid-induced dendritic beading. Finally, the removal of extracellular chloride prevented the kainic acid-induced dendritic beading.Thus, we suggest that the movement of Na(+) and Cl(-), rather than Ca(2+), into cells underlies the focal swellings of interneuron dendrites in hippocampus.

  5. Ternary solution of sodium chloride, succinic acid and water; surface tension and its influence on cloud droplet activation

    Directory of Open Access Journals (Sweden)

    J. Vanhanen

    2008-08-01

    Full Text Available Surface tension of ternary solution of sodium chloride, succinic acid and water was measured as a function of both composition and temperature by using the capillary rise technique. Both sodium chloride and succinic acid are found in atmospheric aerosols, the former being main constituent of marine aerosol. Succinic acid was found to decrease the surface tension of water already at very low concentrations. Sodium chloride increased the surface tension linearly as a function of the concentration. Surface tensions of both binary solutions agreed well with the previous measurements. Succinic acid was found to lower the surface tension even if sodium chloride is present, indicating that succinic acid, as a surface active compound, tends to concentrate to the surface. An equation based on thermodynamical relations was fitted to the data and extrapolated to the whole concentration range by using estimated surface tensions for pure compounds. As a result, we obtained an estimate of surface tensions beyond solubility limits in addition to a fit to the experimental data. The parameterization can safely be used at temperatures from 10 to 30°C. These kinds of parameterizations are important for example in atmospheric nucleation models. To investigate the influence of surface tension on cloud droplet activation, the surface tension parameterization was included in an adiabatic air parcel model. Usually in cloud models the surface tension of pure water is used. Simulations were done for characteristic marine aerosol size distributions consisting of the considered ternary mixture. We found that by using the surface tension of pure water, the amount of activated particles is underestimated up to 8% if particles contain succinic acid and overestimated it up to 8% if particles contain only sodium chloride. The surface tension effect was found to increase with increasing updraft velocity.

  6. Introduction of poly[(2-acryloyloxyethyl trimethyl ammonium chloride)-co-(acrylic acid)] branches onto starch for cotton warp sizing.

    Science.gov (United States)

    Shen, Shiqi; Zhu, Zhifeng; Liu, Fengdan

    2016-03-15

    An attempt has been made to reveal the effect of amphoteric poly(2-acryloyloxyethyl trimethyl ammonium chloride-co-acrylic acid) [P(ATAC-co-AA)] branches grafted onto the backbones of starch upon the adhesion-to-cotton, film properties, and desizability of maize starch for cotton warp sizing. Starch-g-poly[(2-acryloyloxyethyl trimethyl ammonium chloride)-co-(acrylic acid) [S-g-P(ATAC-co-AA)] was prepared by the graft copolymerization of 2-acryloyloxyethyl trimethyl ammonium chloride (ATAC) and acrylic acid (AA) with acid-converted starch (ACS) in aqueous medium using Fe(2+)-H2O2 initiator. The adhesion was evaluated in term of bonding strength according to the FZ/T 15001-2008 whereas the film properties considered included tensile strength, work and percentage elongation at break. The evaluation was undertaken through the comparison of S-g-P(ATAC-co-AA) with ACS, starch-g-poly(acrylic acid), and starch-g-poly(2-acryloyloxyethyl trimethyl ammonium chloride). It was found that the amphoteric branch was able to significantly improve the adhesion and mitigate the brittleness of starch film. Zeta potential of cooked S-g-P(ATAC-co-AA) paste, depending on the mole ratio of ATAC to AA units on P(ATAC-co-AA) branches, had substantial effect on the adhesion and desizability. Increasing the mole ratio raised the potential, which favored the adhesion but disfavored the removal of S-g-P(ATAC-co-AA) from sized cotton warps. Electroneutral S-g-P(ATAC-co-AA) was superior to negatively grafted starch in adhesion and to positively grafted starch in desizability. Generally, it showed better sizing property than ACS, starch-g-poly(acrylic acid), and starch-g-poly(2-acryloyloxyethyl trimethyl ammonium chloride), and had potential in the application of cotton warp sizing.

  7. Migration of additives from poly(vinyl chloride) (PVC) tubes into aqueous media

    DEFF Research Database (Denmark)

    Wang, Qian; Storm, Birgit Kjærside

    2005-01-01

    The stability and migration product of medical PVC tubes plasticized with polyadipates were investigated by ageing in phosphate buffer at pH 1.679 and water at different temperatures. Changes in the PVC tubes were studied by wtaer absorption, weight loss, Fourier infrared spectroscopy (FTIR...... from PVC matrix occurred. When the tube was aged at 110 C, significant degradation of both polyadipates and PVC were observed. Adipic acid and 1,4-butanediol monomers and oligomers of polyadipate were the major migration products from polyadipates in the water ageing solution, while only a relatively...

  8. Direct spectrophotometric determination of Nd and Er in mixed rare earths with 8-hydroxyquinoline-5-sulphonic acid and cetylpyridinium chloride

    Energy Technology Data Exchange (ETDEWEB)

    Shifu Zhou; Naixing Wang (Shandong Univ., Jinan (China). Dept. of Chemistry)

    1990-03-01

    Neodymium and erbium can form stable ternary complexes with 8-hydroxyquinoline-5-sulphonic acid and cetylpyridinium chloride, but a photometric method based on this does not give high enough sensitivity and is subject to interference by cerium. Use of the third derivative spectra, however, eliminates the interference by cerium and increases the sensitivity. (author).

  9. Phase and extraction equilibria in water-polyethyleneglycol ethers of monoethanolamides of synthetic fatty acid-ammonium chloride systems

    Science.gov (United States)

    Lesnov, A. E.; Golovkina, A. V.; Kudryashova, O. S.; Denisova, S. A.

    2016-08-01

    Phase equilibria in layering systems of water, polyethyleneglycol ethers of monoethanolamides of synthetic fatty acids (SFAs) (synthamide-5), and ammonium chloride are studied. The possibility of using such systems for the liquid extraction of metal ions is evaluated. The effect the nature of salting-out agents has on the processes of segregation of the systems has been considered.

  10. Mixed species biofilms of Listeria monocytogenes and Lactobacillus plantarum show enhanced resistance to benzalkonium chloride and peracetic acid

    NARCIS (Netherlands)

    Veen, van der S.; Abee, T.

    2011-01-01

    We investigated the formation of single and mixed species biofilms of Listeria monocytogenes strains EGD-e and LR-991, with Lactobacillus plantarum WCFS1 as secondary species, and their resistance to the disinfectants benzalkonium chloride and peracetic acid. Modulation of growth, biofilm formation,

  11. Calculated Third Order Rate Constants for Interpreting the Mechanisms of Hydrolyses of Chloroformates, Carboxylic Acid Halides, Sulfonyl Chlorides and Phosphorochloridates

    Directory of Open Access Journals (Sweden)

    T. William Bentley

    2015-05-01

    Full Text Available Hydrolyses of acid derivatives (e.g., carboxylic acid chlorides and fluorides, fluoro- and chloroformates, sulfonyl chlorides, phosphorochloridates, anhydrides exhibit pseudo-first order kinetics. Reaction mechanisms vary from those involving a cationic intermediate (SN1 to concerted SN2 processes, and further to third order reactions, in which one solvent molecule acts as the attacking nucleophile and a second molecule acts as a general base catalyst. A unified framework is discussed, in which there are two reaction channels—an SN1-SN2 spectrum and an SN2-SN3 spectrum. Third order rate constants (k3 are calculated for solvolytic reactions in a wide range of compositions of acetone-water mixtures, and are shown to be either approximately constant or correlated with the Grunwald-Winstein Y parameter. These data and kinetic solvent isotope effects, provide the experimental evidence for the SN2-SN3 spectrum (e.g., for chloro- and fluoroformates, chloroacetyl chloride, p-nitrobenzoyl p-toluenesulfonate, sulfonyl chlorides. Deviations from linearity lead to U- or V-shaped plots, which assist in the identification of the point at which the reaction channel changes from SN2-SN3 to SN1-SN2 (e.g., for benzoyl chloride.

  12. Brönsted Acidic Ionic Liquid 1-(1-Propylsulfonic)-3-methylimidazolium-Chloride Catalyzed Hydrolysisof D-Cellobiose in Aqueous Medium

    National Research Council Canada - National Science Library

    Amarasekara, Ananda S; Wiredu, Bernard

    2012-01-01

    Brönsted acidic ionic liquid 1-(1-propylsulfonic)-3-methylimidazolium chloride (PSMIMCl) shows a higher catalytic activity than sulfuric acid in the hydrolysis of D-cellobiose to D-glucose in water at 90-120...

  13. The use of bis (-2-ethylhexyl) phosphoric acid for the extraction of zinc from concentrated ammonium chloride solutions

    Energy Technology Data Exchange (ETDEWEB)

    Amer, S.; Luis, A.; Cuadra, A. de la; Caravaca, C.

    1994-01-01

    The extraction of zinc from concentrated ammonium chloride solutions by means of the bis(-2-ethylhexyl) phosphoric acid is studied. Mass balances and chemical equilibria relating the different chemical species in both phases are presented in order to establish a model describing the behaviour of the different species. Good agreement between experimental data and theoretical curves is obtained. A comparison of the zinc extraction from a strong complexing medium as that of concentrated ammonium chloride solutions with an uncomplexing zinc perchlorate solution is made, in order to see the influence of the complexing effect of the aqueous phase on zinc extraction. (Author) 36 p.

  14. Effect of Postharvest Oxalic Acid and Calcium Chloride on Quality Attributes of Sweet Cherry (Prunus avium L.

    Directory of Open Access Journals (Sweden)

    M. Safa

    2016-02-01

    Full Text Available Introduction: Fruits and vegetables have special importance as a very important part of the human food supply. And from the beginnings of life, man has used these products to supply a part of his food. Nowadays, horticultural products are widely used in the diet. Cherry is one of the deciduous trees in the temperate regions, which is potassium rich. Use of Oxalic acid significantly reduces frost injury in pomegranate fruits during storage at a temperature of 2° C. In fruit trees, the importance of calcium is due to a delay in fruit ripening process and this way products have better portability. Materials and Methods: Firmness test was measured using the FT011 model of penetrometer. For determination of titratable acidity, the 0.1 N sodium hydroxide (NaOH titration method was used. Total Soluble solids content (SSC of fruit was measured by a digital refractometer (PAL-1. For determination of vitamin C in fruit juices, titration method with the indicator, 2,6-di-chlorophenolindophenol was used. Fruit juice pH was measured using pH meter model HI 9811.In order to investigate the effect of postharvest soaking treatment with Oxalic acid on the qualitative specifications and storage life of single grain sweet cherry fruit a research was conducted. This experience was conducted in a completely randomized design with 3 replications separately for the two materials. In this experiment Oxalic acid, in four levels (0,4,6 and 8 mM and Calcium chloride in four levels (0, 40, 55 and 70 mM were applied on the single grain sweet cherry fruit in the form of soaking and sampleswith7-day intervals for a period of 28 days from the fridge out and quanti tate and qualitative traits such as stiffness, weight loss, Titratable acidity, total soluble solids, vitamin C and pH were measured. Results and Discussion: The results showed that compared with control ones all of the concentrations of Oxalic acid and Calcium chloride caused significant differences in the amount

  15. Evaluation of Salicylic Acid and Calcium Chloride Effect on Shelf Life, Quality Properties and Antioxidant Activity of Peach Fruit cv. Amesden after Harvest

    Directory of Open Access Journals (Sweden)

    Gh. Davarynejad

    2015-05-01

    Full Text Available In order to evaluate the effect of different concentrations of postharvest salicylic acid and calcium chloride on shelf life, quality characteristics and antioxidant activity of peach fruit cv. Amesden, an experiment was conducted as factorial based on randomized completely design with three replications. Fruits were harvested at the commercial ripening stage, and fruits were immerged in different concentrations of salicylic acid (1 and 2 mM, calcium chloride (1.5 and 3%, combined salicylic acid and calcium chloride (1-1.5, 1-3, 2-1.5 and 2-3, and distilled water (control for 5 min, then fruits were packed in boxes with polyethylene cover and stored at 4°C with 80-85% relative humidity for 35 days. The changes in weight loss, fruit firmness, rot percentage; pH, total soluble solids, titratable acidity, ascorbic acid and antioxidant activity were estimated in 0 and 35 days during storage. The results showed that the weight loss, rot percentage, pH and total soluble solids significantly increased, while the fruit firmness, titratable acidity, ascorbic acid and antioxidant activity significantly decreased at the end of storage period. The salicylic acid and calcium chloride treatments significantly reduced the weight loss and maintained their firmness. In this condition, the highest of titratable acidity, ascorbic acid and antioxidant activity were observed in treatments of salicylic acid and calcium chloride, while the lowest of total soluble solids and rot percentage was showed in treatments of salicylic acid and calcium chloride than in the control treatment. Also, combined treatment (salicylic acid + calcium chloride had an important effect in relative to each treatment separately. The data indicated that the use of salicylic acid and calcium chloride may be introduced as an effective and successful strategy in postharvest technology of the peach.

  16. Effect of Organic Acid Additions on the General and Localized Corrosion Susceptibility of Alloy 22 in Chloride Solutions

    Energy Technology Data Exchange (ETDEWEB)

    Carranza, R M; Giordano, C M; Rodr?guez, M A; Ilevbare, G O; Rebak, R B

    2007-08-28

    Electrochemical studies such as cyclic potentiodynamic polarization (CPP) and electrochemical impedance spectroscopy (EIS) were performed to determine the corrosion behavior of Alloy 22 (N06022) in 1M NaCl solutions at various pH values from acidic to neutral at 90 C. All the tested material was wrought Mill Annealed (MA). Tests were also performed in NaCl solutions containing weak organic acids such as oxalic, acetic, citric and picric. Results show that the corrosion rate of Alloy 22 was significantly higher in solutions containing oxalic acid than in solutions of pure NaCl at the same pH. Citric and picric acids showed a slightly higher corrosion rate, and acetic acid maintained the corrosion rate of pure chloride solutions at the same pH. Organic acids revealed to be weak inhibitors for crevice corrosion. Higher concentration ratios, compared to nitrate ions, were needed to completely inhibit crevice corrosion in chloride solutions. Results are discussed considering acid dissociation constants, buffer capacity and complex formation constants of the different weak acids.

  17. Study on the interaction of morphine chloride with deoxyribonucleic acid by fluorescence method

    Science.gov (United States)

    Li, J. F.; Dong, C.

    2009-01-01

    The mode and mechanism of the interaction of morphine chloride, an important alkaloid compound to calf thymus deoxyribonucleic acid (ct DNA) was investigated from absorption and fluorescence titration techniques. Hypochromic effect was founded in the absorption spectra of morphine when concentration of DNA increased. The decreased fluorescence study revealed non-cooperative binding of the morphine to DNA with an affinity of 3.94 × 10 3 M -1, and the stoichiometry of binding was characterized to be about one morphine molecule per nucleotide. Stern-Volmer plots at different temperatures proved that the quenching mechanism was static. Ferrocyanide quenching study showed that the magnitude of KSV of the bound morphine was lower than that of the free one. In addition, it was found that ionic strength could affect the binding of morphine and DNA. Fluorescence polarization and denatured DNA studies also applied strong evidences that morphine molecule was partially intercalated between every alternate base pairs of ct DNA. As observed from above experiments, intercalation was well supported as the binding mode of morphine and ct DNA.

  18. Leaching of lead from zinc leach residue in acidic calcium chloride aqueous solution

    Science.gov (United States)

    Wang, Le; Mu, Wen-ning; Shen, Hong-tao; Liu, Shao-ming; Zhai, Yu-chun

    2015-05-01

    A process with potentially reduced environmental impacts and occupational hazards of lead-bearing zinc plant residue was studied to achieve a higher recovery of lead via a cost-effective and environmentally friendly process. This paper describes an optimization study on the leaching of lead from zinc leach residue using acidic calcium chloride aqueous solution. Six main process conditions, i.e., the solution pH value, stirring rate, concentration of CaCl2 aqueous solution, liquid-to-solid (L/S) ratio, leaching temperature, and leaching time, were investigated. The microstructure and components of the residue and tailing were characterized using scanning electron microscopy (SEM) and X-ray diffraction (XRD). On the basis of experimental results, the optimum reaction conditions were determined to be a solution pH value of 1, a stirring rate of 500 r·min-1, a CaCl2 aqueous solution concentration of 400 g·L-1, a liquid-to-solid mass ratio of 7:1, a leaching temperature of 80°C, and a leaching time of 45 min. The leaching rate of lead under these conditions reached 93.79%, with an iron dissolution rate of 19.28%. Silica did not take part in the chemical reaction during the leaching process and was accumulated in the residue.

  19. Ultrasensitive Detection of Ferulic Acid Using Poly(diallyldimethylammonium chloride Functionalized Graphene-Based Electrochemical Sensor

    Directory of Open Access Journals (Sweden)

    Lin-jie Liu

    2014-01-01

    Full Text Available The electrochemical redox of ferulic acid (FA was investigated systematically by cyclic voltammetry (CV with a poly(diallyldimethylammonium chloride functionalized graphene-modified glassy carbon electrode (PDDA-G/GCE as a working electrode. A simple and sensitive differential pulse voltammetry (DPV technique was proposed for the direct quantitative determination of FA in Angelica sinensis and spiked human urine samples for the first time. The dependence of the intensities of currents and potentials on nature of the supporting electrolyte, pH, scan rate, and concentration was investigated. Under optimal conditions, the proposed sensor exhibited excellent electrochemical sensitivity to FA, and the oxidation peak current was proportional to FA concentration in the range of 8.95×10-8 M ~5.29×10-5 M, with a relatively low detection limit of 4.42×10-8 M. This fabricated sensor also displayed acceptable reproducibility, long-term stability, and high selectivity with negligible interferences from common interfering species. Besides, it was applied to detect FA in Angelica sinensis and biological samples with satisfactory results, making it a potential alternative tool for the quantitative detection of FA in pharmaceutical analysis.

  20. Analysis of phthalic acid diesters, monoester, and other plasticizers in polyvinyl chloride household products in Japan.

    Science.gov (United States)

    Kawakami, Tsuyoshi; Isama, Kazuo; Matsuoka, Atsuko

    2011-01-01

    The aim of this study was to determine the concentrations of six phthalic acid diesters (PAEs) [di(2-ethylhexyl) phthalate (DEHP), di-n-butyl phthalate (DBP), butyl benzyl phthalate (BBP), diisononyl phthalate (DINP), di-n-octyl phthalate (DNOP), and diisodecyl phthalate (DIDP)], two non-phthalic plasticizers [di(2-ethylhexyl) adipate (DEHA), 2,2,4-trimethyl-1,3-pentanediol diisobutylate (TMPDIB)], and mono 2-ethylhexyl phthalate(MEHP) in polyvinyl chloride (PVC) household products that children often places in their mouths and/or contact with their skin (41 products, 47 samples) in Japan. The detection frequencies of the studied compounds were as follows: DEHP (79 %), DINP-2 (13 %), DINP-1 (11 %), DBP (8.5 %), DEHA (8.5 %), DIDP (4.3 %), and DNOP (2.1 %). Concentrations of these compounds ranged from 0.021 % to 48 %. BBP and TMPDIB were not detected in the all samples. Most samples contained DEHP and DINP at high concentrations over 0.1 %. High concentrations of PAEs were detected in PVC household products that appear appealing to children and can possibly be licked and chewed by them. Di(2-ethylhexyl) terephtalete, diisononyl 1,2-cyclohexanedicarboxylic acid, acetyl tributyl citrate, and di(2-ethylhexyl) 4-cyclohexene-1,2-dicarboxylate used as substitute plasticizers were also detected in several samples. MEHP was present in 70 % of the samples, with concentrations ranging from trace amounts to 140 μg/g. The ratios of MEHP against DEHP were 6.2 × 10(-4) to 1.6 × 10(-1) %. MEHP in the household products investigated in this study was most probably an impurity in DEHP. The high concentrations of PAEs detected in products that children often place in their mouth reveal the importance of replacing plasticizers in common household products, and not just children's toys, with safer alternatives.

  1. Resistance to benzalkonium chloride, peracetic acid and nisin during formation of mature biofilms by Listeria monocytogenes.

    Science.gov (United States)

    Saá Ibusquiza, P; Herrera, J J R; Cabo, M L

    2011-05-01

    Increase of resistance to the application of benzalkonium chloride (BAC), peracetic acid (PA) and nisin during biofilm formation at 25 °C by three strains of Listeria monocytogenes (CECT 911, CECT 4032, CECT 5873 and BAC-adapted CECT 5873) in different scenarios was compared. For this purpose, resistance after 4 and 11-days of biofilm formation was quantified in terms of lethal dose 90% values (LD(90)), determined according with a dose-response logistic mathematical model. Microscopic analyses after 4 and 11-days of L. monocytogenes biofilm formation were also carried out. Results demonstrated a relation between the microscopic structure and the resistance to the assayed biocides in matured biofilms. The worst cases being biofilms formed by the strain 4032 (in both stainless steel and polypropylene), which showed a complex "cloud-type" structure that correlates with the highest resistance of this strain against the three biocides during biofilm maturation. However, that increase in resistance and complexity appeared not to be dependent on initial bacterial adherence, thus indicating mature biofilms rather than planctonic cells or early-stage biofilms must be considered when disinfection protocols have to be optimized. PA seemed to be the most effective of the three disinfectants used for biofilms. We hypothesized both its high oxidizing capacity and low molecular size could suppose an advantage for its penetration inside the biofilm. We also demonstrated that organic material counteract with the biocides, thus indicating the importance of improving cleaning protocols. Finally, by comparing strains 5873 and 5873 adapted to BAC, several adaptative cross-responses between BAC and nisin or peracetic acid were identified.

  2. Pre-harvest foliar application of humic acid, salicylic acid and calcium chloride to increase quantitative and qualitative traits of Lilium longiflorum cut flowers

    OpenAIRE

    S.N. Mortazavi; Karimi, V.; M.H. Azimi

    2015-01-01

    Lily (Lilium longiflorum L.) is one of the most important potted flowers, which is used largely as cut flower. An experiment, arranged as a factorial besed on completely randomized dasign with three replications, was carried out to evaluate the effects of pre-harvest foliar application of humic acid, salicylic acid and calcium chloride on quality and longevity of lilium cut flowers. Treatments  included humic acid as factor a (0, 100, 500 and 1000 mg/L) and three salicylic acid concentrations...

  3. Polyene Formation Catalyzed by Phosphotungstic Acid and Aluminum Chloride in Thin Films of Poly(Vinyl Alcohol)

    Science.gov (United States)

    Tretinnikov, O. N.; Sushko, N. I.; Maly, A. B.

    2016-01-01

    Formation of linear polyenes -(CH=CH) n - during thermal dehydration of thin layers (9-20 μm) of poly(vinyl alcohol) containing phosphotungstic-acid and aluminum-chloride catalysts was investigated. It was found that the concentration of long-chain ( n ≥ 8) polyenes in films containing phosphotungstic acid increased smoothly with increasing annealing time although the kinetics of the dehydration were independent of the film thickness. The polyene ( n ≥ 8) formation rate in films containing aluminum chloride dropped quickly with decreasing film thickness and increasing annealing time. As a result, long-chain polyenes practically did not form regardless of the annealing time for a film thickness of 11 μm.

  4. Study on Treatment of acidic and highly concentrated fluoride waste water using calcium oxide-calcium chloride

    Science.gov (United States)

    Ren, T.; Gao, X. R.; Zheng, T.; Wang, P.

    2016-08-01

    There are problems with treating acidic waste water containing high concentration fluorine by chemical precipitation, including the low sludge setting velocity and the high difficulty of reaching the criterion. In Heilongjiang province, a graphite factory producing high-purity graphite generates acidic waste water with a high concentration of fluorine. In this paper, the effect of removals on the concentration of fluoride with the combined treatment of calcium oxide and calcium chloride were discussed with regard to acid waste water. The study improved the sludge characteristics by using polyacrylamide (PAM) and polymeric aluminum chloride (PAC). The effect of different coagulants on sludge was evaluated by the sludge settlement ratio (SV), sludge volume index (SVI) and sludge moisture content. The results showed that the optimal combination for 100 ml waste water was calcium oxide addition amount of 14 g, a calcium chloride addition amount of 2.5 g, a PAM addition amount of 350 mg/L, and the effluent fluoride concentration was below 6 mg/L. PAM significantly improved the sludge settling velocity. The sludge settlement ratio reduced from 87.6% to 60%. The process for wastewater treatment was easily operated and involved low expenditure.

  5. Growth/no growth interfaces of table olive related yeasts for natamycin, citric acid and sodium chloride.

    Science.gov (United States)

    Arroyo-López, F N; Bautista-Gallego, J; Romero-Gil, V; Rodríguez-Gómez, F; Garrido-Fernández, A

    2012-04-16

    The present work uses a logistic/probabilistic model to obtain the growth/no growth interfaces of Saccharomyces cerevisiae, Wickerhamomyces anomalus and Candida boidinii (three yeast species commonly isolated from table olives) as a function of the diverse combinations of natamycin (0-30 mg/L), citric acid (0.00-0.45%) and sodium chloride (3-6%). Mathematical models obtained individually for each yeast species showed that progressive concentrations of citric acid decreased the effect of natamycin, which was only observed below 0.15% citric acid. Sodium chloride concentrations around 5% slightly increased S. cerevisiae and C. boidinii resistance to natamycin, although concentrations above 6% of NaCl always favoured inhibition by this antimycotic. An overall growth/no growth interface, built considering data from the three yeast species, revealed that inhibition in the absence of citric acid and at 4.5% NaCl can be reached using natamycin concentrations between 12 and 30 mg/L for growth probabilities between 0.10 and 0.01, respectively. Results obtained in this survey show that is not advisable to use jointly natamycin and citric acid in table olive packaging because of the observed antagonistic effects between both preservatives, but table olives processed without citric acid could allow the application of the antifungal.

  6. Enthalpic Pair Interaction of Rubidium Chloride with α-Amino Acid in Water at 298.15K

    Institute of Scientific and Technical Information of China (English)

    胡满成; 杨茜; 蒋育澄; 夏树屏

    2005-01-01

    The mixing enthalpies of aqueous heavy rare alkali metal chloride RbC1 solutions with aqueous α-amino acid (Loglycine, L-alanine and α-aminobutyric acid) solutions, as well as the dilution enthalpies of RbC1 and α-amino acid solutions in pure water had been measured at 298.15K. The transfer enthalpies of RbCI from pure water to aqueous α-amino acid solutions could be obtained from these data. The enthalpic pair interaction parameters of RbC1 with α-amino acid in water have been evaluated according to the McMillan-Mayer theory and discussed in terms of the electrostatic interaction, structure interaction and Savage-wood group additivity mode.

  7. POLYMER-SUPPORTED LEWIS ACID CATALYSTS. VI. POLYSTYRENE-BONDED STANNIC CHLORIDE CATALYST

    Institute of Scientific and Technical Information of China (English)

    RAN Ruicheng; FU Diankui

    1991-01-01

    A polystyrene-bonded stannic chloride catalyst was synthesized by the method of lithium polystyryl combined with stannic chloride. This catalyst is a polymeric organometallic compound containing 0.25 mmol Sn(IV)/g catalyst. The catalyst showed sufficient stability and catalytic activity in organic reaction such as esterification, acetalation and ketal formation, and it could be reused many times without losing its catalytic activity.

  8. Comments on the paper: 'Optical reflectance, optical refractive index and optical conductivity measurements of nonlinear optics for L-aspartic acid nickel chloride single crystal'

    Science.gov (United States)

    Srinivasan, Bikshandarkoil R.; Naik, Suvidha G.; Dhavskar, Kiran T.

    2016-02-01

    We argue that the 'L-aspartic acid nickel chloride' crystal reported by the authors of the title paper (Optics Communications, 291 (2013) 304-308) is actually the well-known diaqua(L-aspartato)nickel(II) hydrate crystal.

  9. Extraction of palladium(Ⅱ) with OTMSO from acidic media

    Institute of Scientific and Technical Information of China (English)

    WU Songping; MENG Shuyuan; GU Guobang; ZHUANG Zhiqiang

    2004-01-01

    The extraction of palladium(Ⅱ) from acidic media with cyclic sulfoxide derivative-α-octyl-tetrahydrothiophene-l-oxide (OTMSO) was investigated. The extraction efficiency of palladination number was studied with slope method. The result indicates that coordination number is 2. FT-IR spectra were used to analyze the structure of complex and coordinated atom in complex. Pd is coordinated with both oxygen and sulfur atom in S=O group in OTMSO .The situation and intensity of peaks contributed by complex prepared from various acidity were different. The recovery of palladium(Ⅱ) with OTMSO from scrap containing palladium was discussed. After silver and bismuth were removed, the feed solution was extracted three times by 40% (volume fraction) OTMSO-kerosene. The loaded organic phase was scrubbed three times,and stripped three times by 2 mol@L-1 NH3·H2O solution.The total recovery of palladium was 99.8%,and the purity of palladium was 99.8%.

  10. Fractal analysis of polyferric chloride-humic acid (PFC-HA) flocs in different topological spaces.

    Science.gov (United States)

    Wang, Yili; Lu, Jia; Baiyu, Du; Shi, Baoyou; Wang, Dongsheng

    2009-01-01

    The fractal dimensions in different topological spaces of polyferric chloride-humic acid (PFC-HA) flocs, formed in flocculating different kinds of humic acids (HA) water at different initial pH (9.0, 7.0, 5.0) and PFC dosages, were calculated by effective density-maximum diameter, image analysis, and N2 absorption-desorption methods, respectively. The mass fractal dimensions (Df) of PFC-HA flocs were calculated by bi-logarithm relation of effective density with maximum diameter and Logan empirical equation. The Df value was more than 2.0 at initial pH of 7.0, which was 11% and 13% higher than those at pH 9.0 and 5.0, respectively, indicating the most compact flocs formed in flocculated HA water at initial pH of 7.0. The image analysis for those flocs indicates that after flocculating the HA water at initial pH greater than 7.0 with PFC flocculant, the fractal dimensions of D2 (logA vs. logdL) and D3 (logVsphere VS. logdL) of PFC-HA flocs decreased with the increase of PFC dosages, and PFC-HA flocs showed a gradually looser structure. At the optimum dosage of PFC, the D2 (logA vs. logdL) values of the flocs show 14%-43% difference with their corresponding Df, and they even had different tendency with the change of initial pH values. However, the D2 values of the flocs formed at three different initial pH in HA solution had a same tendency with the corresponding Dr. Based on fractal Frenkel-Halsey-Hill (FHH) adsorption and desorption equations, the pore surface fractal dimensions (Ds) for dried powders of PFC-HA flocs formed in HA water with initial pH 9.0 and 7.0 were all close to 2.9421, and the Ds values of flocs formed at initial pH 5.0 were less than 2.3746. It indicated that the pore surface fractal dimensions of PFC-HA flocs dried powder mainly show the irregularity from the mesopore-size distribution and marcopore-size distribution.

  11. Kinetics of the oxidative hydroxylation of tetraphosphorus in the presence of copper(II chloride modified by humic (fulvo- acid

    Directory of Open Access Journals (Sweden)

    Zhaksyntay Kairbekov

    2012-12-01

    Full Text Available It was established that in mild conditions (50-70 oC, РО2= 1 atm white phosphorus effectively is oxidized by oxygen in water-toluene solutions of copper(II chloride modified by humic (fulvo- acid to give mainly phosphoric acid. Humic (fulvo- acid was extracted from brown coal of domestic deposit Kiyakty. For determination of optimum parameters of fulvo-acid extraction the laboratory experiments were carried out using the method of experiment planning. The kinetics, intermediate and final products, optimum conditions of new catalytic reaction of P4 oxidation by oxygen in water medium were defined by kinetics, volumometry, redox-potentiometry, 31Р{1Н} NMR spectroscopy and  titration. 

  12. Thermotropic liquid crystalline polyesters derived from bis-(4-hydroxybenzoyloxy)-2-methyl-1,4-benzene and aliphatic dicarboxylic acid chlorides

    Indian Academy of Sciences (India)

    Khudbudin Mulani; Mohasin Momin; Nitin Ganjave; Nayaku Chavan

    2015-09-01

    A series of thermotropic liquid crystalline polyesters derived from bis-(4-hydroxybenzoyloxy)-2-methyl-1,4-benzene (BHBOMB) and aliphatic dicarboxylic acid chlorides were investigated. All these polyesters were synthesized by interfacial polycondensation method and characterized by differential scanning calorimetry and wide-angle X-ray diffractometer. These polyesters consist of BHBOMB as a mesogenic diol and aliphatic diacid chlorides were used as flexible spacers. The length of oligomethylene units in polymer was varied from the trimethylene to the dodecamethylene groups. The transition temperatures and thermodynamic properties were studied for all these polymers. All these polyesters were soluble in chlorinated solvents such as chloroform, dichloromethane, dichloroethane, etc. More importantly, all these polyesters exhibited very large mesophase stability.

  13. Epoxidation of olefins and allylic alcohols with hydrogen peroxide catalyzed by heteropoly acids in the presence of cetylpyridinium chloride

    Energy Technology Data Exchange (ETDEWEB)

    Okabayashi, Takuji; Yamawaki, Kazumasa; Nishihara, Hideki; Yamada, Hiroshi; Ura, Toshikazu; Ishii, Yasutaka; Ogawa, Masaya

    1987-11-01

    The epoxidation of olefins and allylic alcohols with aqueous hydrogen peroxide could be achieved in good yield when 12-tungustophosphoric acid(WPA) was used with two phase condition using chloroform as the solvent. From the epoxidation result by 12-molybdophosphoric acid(MPA) and WPA catalysts, epoxidation activity of WPA catalyst was found to be remarkably higher than that of MPA. The rate of epoxidation by heteropoly acids catalyst depended markedly upon the activity of the reaction medium. Epoxidation of allylic alcohols with hydrogen peroxide proceeded under mild conditions, resulting good yield of epoxi-alcohols. Epoxidation of olefins by WPA/cetylpyridium chloride was confirmed to be promoted selectively with cheap and pure hydrogen peroxide, resulting good yield. (3 figs, 2 tabs, 18 refs)

  14. Kinetics of the oxidative hydroxylation of sodium hypophosphite in the presence of copper (II chloride modified by humic (fulvo- acid

    Directory of Open Access Journals (Sweden)

    Zhaksyntay Kairbekov

    2012-12-01

    Full Text Available It was established that in soft conditions (50-70oC, PO2 = 1 atm sodium hypophosphite effectively is oxidized by oxygen in water solutions of copper(II chloride  to give mainly a phosphorous acid. Humic (fulvo- acid was extracted from brown coal of domestic deposit Kiyakty. For determination of optimum parameters of fulvo-acid extraction the laboratory experiments were carried out using the method of experiment planning. The kinetics, the intermediate and final products, optimal conditions of new catalytic reaction of NaH2PO2 oxidation by oxygen in water solution were defined by kinetics, volumometry, redox-potentiometry and a titration.

  15. Cytotoxic effects of nanosilver are highly dependent on the chloride concentration and the presence of organic compounds in the cell culture media.

    Science.gov (United States)

    Kaiser, Jean-Pierre; Roesslein, Matthias; Diener, Liliane; Wichser, Adrian; Nowack, Bernd; Wick, Peter

    2017-01-06

    Nanosilver shows great promise for use in industrial, consumer or medical products because of its antimicrobial properties. However, the underlying mechanisms of the effects of silver nanoparticles on human cells are still controversial. Therefore, in the present study the influence of the chloride concentration and different serum content of culture media on the cytotoxic effects of nanosilver was systematically evaluated. Our results show that nanosilver toxicity was strongly affected by the composition of the culture media. The chloride concentration, as well as the carbon content affected the silver agglomeration and the complex formation. But also the dissolution of nanosilver and the availability of free silver ions (Ag(+)) were severely affected by the compositions of the culture media. Cells, only exposed to silver particles in suspension and dissolved silver complexes, did not show any effects under all conditions. Nanosilver agglomerates and silver complexes were not very soluble. Thus, cells growing on the bottom of the culture dishes were exposed to sedimented nanosilver agglomerates and precipitated silver complexes. Locally, the concentration of silver on the cell surface was very high, much higher compared the silver concentration in the bulk solution. The cytotoxic effects of nanosilver are therefore a combination of precipitated silver complexes and organic silver compounds rather than free silver ions. Silver coatings are used in health care products due to their bacteriostatic or antibacterial properties. The assessment of the toxicity of a certain compound is mostly done using in vitro assays. Therefore, cytotoxicity studies of nanosilver using human cell cultures have to be undertaken under well controlled and understood cultivations conditions in order to improve the compatibility of different studies. Especially when eukaryotic versus prokaryotic systems are compared for the evaluation of the use of nanosilver as antibacterial coatings for

  16. Combined effects of simulated acid rain and lanthanum chloride on chloroplast structure and functional elements in rice.

    Science.gov (United States)

    Hu, Huiqing; Wang, Lihong; Zhou, Qing; Huang, Xiaohua

    2016-05-01

    Acid rain and rare earth element (REE) pollution exist simultaneously in many agricultural regions. However, how REE pollution and acid rain affect plant growth in combination remains largely unknown. In this study, the combined effects of simulated acid rain and lanthanum chloride (LaCl3) on chloroplast morphology, chloroplast ultrastructure, functional element contents, chlorophyll content, and the net photosynthetic rate (P n) in rice (Oryza sativa) were investigated by simulating acid rain and rare earth pollution. Under the combined treatment of simulated acid rain at pH 4.5 and 0.08 mM LaCl3, the chloroplast membrane was smooth, proteins on this membrane were uniform, chloroplast structure was integrated, and the thylakoids were orderly arranged, and simulated acid rain and LaCl3 exhibited a mild antagonistic effect; the Mg, Ca, Mn contents, the chlorophyll content, and the P n increased under this combined treatment, with a synergistic effect of simulated acid rain and LaCl3. Under other combined treatments of simulated acid rain and LaCl3, the chloroplast membrane surface was uneven, a clear "hole" was observed on the surface of chloroplasts, and the thylakoids were dissolved and loose; and the P n and contents of functional elements (P, Mg, K, Ca, Mn, Fe, Ni, Cu, Zn and Mo) and chlorophyll decreased. Under these combined treatments, simulated acid rain and LaCl3 exhibited a synergistic effect. Based on the above results, a model of the combined effects of simulated acid rain and LaCl3 on plant photosynthesis was established in order to reveal the combined effects on plant photosynthesis, especially on the photosynthetic organelle-chloroplast. Our results would provide some references for further understanding the mechanism of the combined effects of simulated acid rain and LaCl3 on plant photosynthesis.

  17. Highly microporous carbons derived from a complex of glutamic acid and zinc chloride for use in supercapacitors

    Science.gov (United States)

    Dong, Xiao-Ling; Lu, An-Hui; He, Bin; Li, Wen-Cui

    2016-09-01

    The selection of carbon precursor is an important factor when designing carbon materials. In this study, a complex derived from L-glutamic acid and zinc chloride was used to prepare highly microporous carbons via facile pyrolysis. L-glutamic acid, a new carbon precursor with nitrogen functionality, coordinated with zinc chloride resulted in a homogeneous distribution of Zn2+ on the molecular level. During pyrolysis, the evaporation of the in situ formed zinc species creates an abundance of micropores together with the inert gases. The obtained carbons exhibit high specific surface area (SBET: 1203 m2 g-1) and a rich nitrogen content (4.52 wt%). In excess of 89% of the pore volume consists of micropores with pore size ranging from 0.5 to 1.2 nm. These carbons have been shown to be suitable for use as supercapacitor electrodes, and have been tested in 6 M KOH where a capacitance of 217 F g-1 was achieved at a current density of 0.5 A g-1. A long cycling life of 30 000 cycles was achieved at a current density of 1 A g-1, with only a 9% loss in capacity. The leakage current through a two-electrode device was measured as 2.3 μA per mg of electrode and the self-discharge characteristics were minimal.

  18. Effects of applied potential on the stress corrosion cracking behavior of 7003 aluminum alloy in acid and alkaline chloride solutions

    Science.gov (United States)

    Zhang, Xiao-yan; Song, Ren-guo; Sun, Bin; Lu, Hai; Wang, Chao

    2016-07-01

    Potentiodynamic polarization tests and slow strain rate test (SSRT) in combination with fracture morphology observations were conducted to investigate the stress corrosion cracking (SCC) behavior of 7003 aluminum alloy (AA7003) in acid and alkaline chloride solutions under various applied potentials ( E a). The results show that AA7003 is to a certain extent susceptible to SCC via anodic dissolution (AD) at open-circuit potential (OCP) and is highly susceptible to hydrogen embrittlement (HE) at high negative E a in the solutions with pH levels of 4 and 11. The susceptibility increases with negative shift in the potential when E a is less than -1000 mV vs. SCE. However, the susceptibility distinctly decreases because of the inhibition of AD when E a is equal to -1000 mV vs. SCE. In addition, the SCC susceptibility of AA7003 in the acid chloride solution is higher than that in the alkaline solution at each potential. Moreover, the effect of hydrogen on SCC increases with increasing hydrogen ion concentration.

  19. effect of sowing media and gibberellic acid on the growth and ...

    African Journals Online (AJOL)

    DR. AMIN

    ... for better root establishment, growth. and development in relation to the three ... Keywords: Gibbrellic Acid, Sowing Media, Bougainvillea glabra, Ixora coccinea, ..... India. 2nd Edition Indian Council of Agricultural. Research, New Delhi, India.

  20. Compound bioflocculant and polyaluminum chloride in kaolin-humic acid coagulation: factors influencing coagulation performance and floc characteristics.

    Science.gov (United States)

    Li, Ruihua; Gao, Baoyu; Huang, Xin; Dong, Hongyu; Li, Xiaochen; Yue, Qinyan; Wang, Yan; Li, Qian

    2014-11-01

    The objective of this study was to investigate the influence of coagulant dosage and pH on coagulation performance and floc properties using polyaluminum chloride (PAC) and compound bioflocculant (CBF) dual-coagulant in kaolin-humic acid (HA) treatment. Results showed that as PAC dosage rose, comparatively better coagulation efficiencies and floc characteristics were achieved due to stronger charge neutralization and sweeping effect. Addition of CBF could enhance coagulation performance and floc properties, including size, strength and recoverability, except fractal dimension. Solution pH had a significant effect on coagulation efficiencies and flocs formation. Under acidic condition, flocs showed higher strength and recoverability but lower fractal dimension, where charge neutralization was the foremost mechanism. More compact flocs were generated under alkaline condition due to the sweeping effect of hydrolyzed Al species. Copyright © 2014 Elsevier Ltd. All rights reserved.

  1. Preparation of robust polyamide microcapsules by interfacial polycondensation of p-phenylenediamine and sebacoyl chloride and plasticization with oleic acid.

    Science.gov (United States)

    Rosa, Natacha; Martins, Gabriela V; Bastos, Margarida M S M; Gois, Joana R; Coelho, Jorge F J; Marques, Juliana; Tavares, Carlos J; Magalhães, Fernão D

    2015-01-01

    Microcapsules produced by interfacial polycondensation of p-phenylenediamine (PPD) and sebacoyl chloride (SC) were studied. The products were characterized in terms of morphology, mean diameter and effectiveness of dodecane encapsulation. The use of Tween 20 as dispersion stabilizer, in comparison with polyvinyl alcohol (PVA), reduced considerably the mean diameter of the microcapsules and originated smoother wall surfaces. When compared to ethylenediamine (EDA), microcapsules produced with PPD monomer were more rigid and brittle, prone to fracture during processing and ineffective retention of the core liquid. The use of diethylenetriamine (DETA) cross-linker in combination with PPD did not decrease capsule fragility. On the other hand, addition of a small fraction of oleic acid to the organic phase remarkably improved wall toughness and lead to successful encapsulation of the core-oil. Oleic acid is believed to act as a plasticizer. Its incorporation in the polymeric wall was demonstrated by FTIR and (1)H-NMR.

  2. Electrolytic reduction of U(VI) to U(IV) in acidic chloride and acidic sulfate solutions

    Science.gov (United States)

    Majima, Hiroshi; Awakura, Yasuhiro; Hirono, Shuichiro

    1986-01-01

    In order to examine the applicability of the electrolytic reduction process of U(VI) (originally developed for the chloride system by PNC) to the sulfate solution system, a fundamental study was made. In this study, the concentrations of various chemical species in the catholytes were calculated at 298 K at various percentages of uranium reduction, taking the chloro-complex and sulfato-complex formation reactions of uranium into consideration. The polarization characteristics of the electrolytic reduction of uranyl chloride and uranyl sulfate were determined, using titanium and platinum cathodes, respectively, at 303 ± 1 K. In conjunction with this process, the electrical conductivity of the catholyte, the electrical resistivity of the cation exchange membrane, and the diffusion coefficient of uranyl sulfate were also determined.

  3. EFFECT OF DIATOMEAOUS EARTH TREATMENT USING HYDROGEN CHLORIDE AND SULFURIC ACID ON KINETICS OF CADMIUM(II ADSORPTION

    Directory of Open Access Journals (Sweden)

    Nuryono Nuryono

    2010-06-01

    Full Text Available In this research, treatment of diatomaceous earth, Sangiran, Central Java using hydrogen chloride (HCl and sulfuric acid (H2SO4 on kinetics of Cd(II adsorption in aqueous solution has been carried out. The work was conducted by mixing an amount of grounded diatomaceous earth (200 mesh in size with HCl or H2SO4 solution in various concentrations for two hours at temperature range of 100 - 150oC. The mixture was then filtered and washed with water until the filtrate pH is approximately 7 and then the residue was dried for four hours at a temperature of 70oC. The product was used as an adsorbent to adsorb Cd(II in aqueous solution with various concentrations. The Cd(II adsorbed was determined by analyzing the rest of Cd(II in the solution using atomic absorption spectrophotometry. The effect of treatment was evaluated from kinetic parameter of adsorption rate constant calculated based on the simple kinetic model. Results showed  that before equilibrium condition reached, adsorpstion of Cd(II occurred through two steps, i.e. a step tends to follow a reaction of irreversible first order  (step I followed by reaction of reversible first order (step II. Treatment with acids, either hydrogen chloride or sulfuric acid, decreased adsorption rate constant for the step I from 15.2/min to a range of 6.4 - 9.4/min.  However, increasing concentration of acid (in a range of concentration investigated did not give significant and constant change of adsorption rate constant. For step II process,  adsorption involved physical interaction with the sufficient low adsorption energy (in a range of 311.3 - 1001 J/mol.     Keywords: adsorption, cdmium, diatomaceous earth, kinetics.

  4. Survival mechanism of Escherichia coli O157:H7 against combined treatment with acetic acid and sodium chloride.

    Science.gov (United States)

    Lee, Sun-Young; Kang, Dong-Hyun

    2016-05-01

    The combination of salt and acid is commonly used in the production of many foods, including pickles and fermented foods. However, in our previous studies, the addition of salt significantly reduced the inhibitory effect of acetic acid on Escherichia coli O157:H7 in laboratory media and pickled cucumbers. Therefore, this study was conducted to determine the mechanism by which salt confers resistance against acetic acid in E. coli O157:H7. The addition of high concentrations (up to 9% or 15% [w/v]) of salt increased the resistance of E. coli O157:H7 to acetic acid treatment. Combined treatment with acetic acid and salt showed varying results among different bacterial strains (an antagonistic effect for E. coli O157:H7 and Shigella and a synergistic effect for Listeria monocytogenes and Staphylococcus aureus). The addition of salt increased the cytoplasmic pH of E. coli O157:H7, but decreased the cytoplasmic pH of L. monocytogenes and S. aureus on treatment with acetic acid. Therefore, the addition of salt increases the acid resistance of E. coli O157:H7 possibly by increasing its acid resistance response and consequently preventing the acidification of its cytoplasm by organic acids.

  5. Bile acids stimulate chloride secretion through CFTR and calcium-activated Cl- channels in Calu-3 airway epithelial cells.

    Science.gov (United States)

    Hendrick, Siobhán M; Mroz, Magdalena S; Greene, Catherine M; Keely, Stephen J; Harvey, Brian J

    2014-09-01

    Bile acids resulting from the aspiration of gastroesophageal refluxate are often present in the lower airways of people with cystic fibrosis and other respiratory distress diseases. Surprisingly, there is little or no information on the modulation of airway epithelial ion transport by bile acids. The secretory effect of a variety of conjugated and unconjugated secondary bile acids was investigated in Calu-3 airway epithelial cells grown under an air-liquid interface and mounted in Ussing chambers. Electrogenic transepithelial ion transport was measured as short-circuit current (Isc). The taurine-conjugated secondary bile acid, taurodeoxycholic acid (TDCA), was found to be the most potent modulator of basal ion transport. Acute treatment (5 min) of Calu-3 cells with TDCA (25 μM) on the basolateral side caused a stimulation of Isc, and removal of extracellular Cl(-) abolished this response. TDCA produced an increase in the cystic fibrosis transmembrane conductance regulator (CFTR)-dependent current that was abolished by pretreatment with the CFTR inhibitor CFTRinh172. TDCA treatment also increased Cl(-) secretion through calcium-activated chloride (CaCC) channels and increased the Na(+)/K(+) pump current. Acute treatment with TDCA resulted in a rapid cellular influx of Ca(2+) and increased cAMP levels in Calu-3 cells. Bile acid receptor-selective activation with INT-777 revealed TGR5 localized at the basolateral membrane as the receptor involved in TDCA-induced Cl(-) secretion. In summary, we demonstrate for the first time that low concentrations of bile acids can modulate Cl(-) secretion in airway epithelial cells, and this effect is dependent on both the duration and sidedness of exposure to the bile acid.

  6. Scientific Opinion on the safety assessment of the active substances iron powder, activated carbon, calcined kaolin, sodium chloride, polyacrylic acid, sodium salt, crosslinked and calcium chloride, for use as active system in food contact materials

    Directory of Open Access Journals (Sweden)

    EFSA Panel on Food Contact Materials, Enzymes, Flavourings and Processing Aids (CEF

    2014-05-01

    Full Text Available This scientific opinion of the EFSA Panel on Food Contact Materials, Enzymes, Flavourings and Processing Aids deals with the safety assessment of the active substances iron powder, activated carbon, calcined kaolin, sodium chloride, polyacrylic acid, sodium salt, crosslinked and calcium chloride, used in mixture which is packed into labels, for absorbing oxygen from the headspace surrounding packed food. All substances of this formulation have been evaluated and approved for use as additives in plastic food contact materials or as food supplements. Migration of substances from the labels and formation and release of volatile constituents are not expected under the intended conditions of use. The CEF Panel concluded that the use of substances iron powder, activated carbon, calcined kaolin, sodium chloride, polyacrylic acid, sodium salt, crosslinked and calcium chloride does not raise a safety concern when used in oxygen absorbers in labels, which prevent the physical release of their content into the food. When placed in the headspace of the packaging or when used in direct contact with foods, the labels should not intentionally or unintentionally come into direct contact with liquid foods or foods that have an external aqueous phase on the surface such as sliced fruits.

  7. Uranium, Cesium, and Mercury Leaching and Recovery from Cemented Radioactive Wastes in Sulfuric Acid and Iodide Media

    Directory of Open Access Journals (Sweden)

    Nicolas Reynier

    2015-11-01

    Full Text Available The Canadian Nuclear Laboratories (CNL is developing a long-term management strategy for its existing inventory of solid radioactive cemented wastes, which contain uranium, mercury, fission products, and a number of minor elements. The composition of the cemented radioactive waste poses significant impediments to the extraction and recovery of uranium using conventional technology. The goal of this research was to develop an innovative method for uranium, mercury and cesium recovery from surrogate radioactive cemented waste (SRCW. Leaching using sulfuric acid and saline media significantly improves the solubilization of the key elements from the SRCW. Increasing the NaCl concentration from 0.5 to 4 M increases the mercury solubilization from 82% to 96%. The sodium chloride forms a soluble mercury complex when mercury is present as HgO or metallic mercury but not with HgS that is found in 60 °C cured SRCW. Several leaching experiments were done using a sulfuric acid solution with KI to leach SRCW cured at 60 °C and/or aged for 30 months. Solubilization yields are above 97% for Cs and 98% for U and Hg. Leaching using sulfuric acid and KI improves the solubilization of Hg by oxidation of Hg0, as well as HgS, and form a mercury tetraiodide complex. Hg and Cs were selectively removed from the leachate prior to uranium recovery. It was found that U recovery from sulfuric leachate in iodide media using the resin Lewatit TP260 is very efficient. Considering these results, a process including effluent recirculation was applied. Improvements of solubilization due to the recycling of chemical reagents were observed during effluent recirculation.

  8. Corrosion behaviour of Fe[sub 80-x]Co[sub x]B[sub 10]Si[sub 10] metallic glasses in sulphate and chloride media

    Energy Technology Data Exchange (ETDEWEB)

    Angelini, E. (Dept. of Materials Science and Chemical Engineering, Politechnic of Turin (Italy)); Antonione, C. (Dept. of Inorganic Chemistry, Physical Chemistry, Materials Chemistry, Univ. of Turin (Italy)); Baricco, M. (Dept. of Inorganic Chemistry, Physical Chemistry, Materials Chemistry, Univ. of Turin (Italy)); Bianco, P. (Chemical Lab. of the Chamber of Commerce, Turin (Italy)); Rosalbino, F. (Dept. of Materials Science and Chemical Engineering, Politechnic of Turin (Italy)); Zucchi, F. (Corrosion Study Center Aldo Dacco, Univ. of Ferrara (Italy))

    1993-03-01

    The corrosion behaviour of a series of glassy alloys, Fe[sub 80-x]Co[sub x]B[sub 10]Si[sub 10] (x = 0, 15, 30, 55, 70, 80), well known for their magnetic properties, has been investigated in sulphate- and chloride-containing solutions of different pH, employing weight loss measurements. In order to point out preferential dissolution reactions of metallic glasses constituent elements, analyses of the solutions were performed after corrosion tests by means of the source mass spectrometry and optical emission spectroscopy. A higher aggressivity of the sulphate containing solutions has been observed. The amorphous alloys exhibit an increased corrosion resistance with the increase of cobalt content. Increasing the pH of the aggressive media from 1.5 to 5.6 a decrease of two orders of magnitude in the corrosion rates has been observed. The corrosion products have been investigated by means of X-ray diffraction and scanning electron microscopy. Hydrated iron oxide Fe[sub 2]O[sub 3].H[sub 2]O was the major constituent of the film formed on iron-rich amorphous alloys immersed in sulphate-containing media. (orig.)

  9. Effect of chlormequat chloride, ß-naphthoxyacetic acid and ethephon on early and total yield of tomato in open field

    Directory of Open Access Journals (Sweden)

    Jan Borkowski

    2013-12-01

    Full Text Available Tomato seedlings in hotbed with Antywylegacz (chlormequat chloride to suppress their excessive elongation before transplanting, were used. Their first 2-3 flower clusters were dipped in the field in Betokson (ß-naphthoxyacetic acid to induce better early fruit set and the plants were sprayed with Ethrel (ethephon just before the first fruits become pink, to stimulate earlier ripening and increase early yield. The experiment was carried out during 3 years with the cultivars 'Venture', 'New Yorker' and 'Nesthackchen' (only in 1975. Application of chlormequat alone prevented excessive growth of the seedlings but did not increase early yield significantly. ß-naphthoxyacetic acid alone was effectiveevery year and always increased early yield. Chlormequat followed by ß-naphthoxyacetic treatment showed always a tendency to increase early yield more than ß-naphthoxyacetic acid alone. Treatment with ß-naphthoxyacetic acid, alone or in combination with other treatments, lowered the total yield. Ethephon used solely or in combination with other treatments usually was ineffective.

  10. Corrosion Behavior of Alloy 22 in Chloride Solutions Containing Organic Acids

    Energy Technology Data Exchange (ETDEWEB)

    Carranza, R M; Giordano, C M; Rodr?guez, M A; Rebak, R B

    2005-11-04

    Alloy 22 (N06022) is a nickel based alloy containing alloying elements such as chromium, molybdenum and tungsten. It is highly corrosion resistant both under reducing and under oxidizing conditions. Electrochemical studies such as electrochemical impedance spectroscopy (EIS) were performed to determine the corrosion behavior of Alloy 22 in 1M NaCl solutions at various pH values from acidic to neutral at 90 C. Tests were also carried out in NaCl solutions containing oxalic acid or acetic acid. It is shown that the corrosion rate of Alloy 22 was higher in a solution containing oxalic acid than in a solution of the same pH acidified with HCl. Acetic acid was not corrosive to Alloy 22. The corrosivity of oxalic acid was attributed to its capacity to form stable complex species with metallic cations from Alloy 22.

  11. Surfactant-assisted specific-acid catalysis of Diels-Alder reactions in aqueous media

    NARCIS (Netherlands)

    Mubofu, Egid B.; Engberts, Jan B. F. N.

    2007-01-01

    Surfactant-assisted specific-acid catalysis (SASAC) for Diets-Alder reactions of dienophiles 1 and 4 with cyclopentadiene 2 in aqueous media at 32 C was studied. This study showed that acidified anionic surfactants (pH 2) such as sodium dodecyl sulfate (SDS) and linear alkylbenzene sulfonic acid (LA

  12. Phytic Acid and Sodium Chloride Show Marked Synergistic Bactericidal Effects against Nonadapted and Acid-Adapted Escherichia coli O157:H7 Strains.

    Science.gov (United States)

    Kim, Nam Hee; Rhee, Min Suk

    2015-12-04

    The synergistic antimicrobial effects of phytic acid (PA), a natural extract from rice bran, plus sodium chloride against Escherichia coli O157:H7 were examined. Exposure to NaCl alone at concentrations up to 36% (wt/wt) for 5 min did not reduce bacterial populations. The bactericidal effects of PA alone were much greater than those of other organic acids (acetic, citric, lactic, and malic acids) under the same experimental conditions (P acid-adapted cells, reducing their numbers to unrecoverable levels (>7-log CFU/ml reduction). Flow cytometry confirmed that PA disrupted the cell membrane to a greater extent than did other organic acids, although the cells remained viable. The combination of PA and NaCl induced complete disintegration of the cell membrane. By comparison, none of the other organic acids acted synergistically with NaCl, and neither did NaCl-HCl solutions at the same pH values as the test solutions of PA plus NaCl. These results suggest that PA has great potential as an effective bacterial membrane-permeabilizing agent, and we show that the combination is a promising alternative to conventional chemical disinfectants. These findings provide new insight into the utility of natural compounds as novel antimicrobial agents and increase our understanding of the mechanisms underlying the antibacterial activity of PA.

  13. Functionalyzed Polyampholytes on the Basis of Copolymers of N,N-Diallyl-N,N-dimethylammonium Chloride and Maleic Acid

    DEFF Research Database (Denmark)

    Vlasov, Petr; Chernyy, Sergey; Domnina, Nina

    2010-01-01

    Polyampholytes were prepared by radical copolymerization of N,N-diallyl-N,N-dimethylammonium chloride and maleic acid. The esterification and subsequent hydrazinolysis permitted to introduce hydrazide groups capable of formation of the coordination bond with copper ions. The formation of complex...... between the hydrazide groups of polyampholyte and Cu2+ ions was established by electronic spectroscopy. It was shown that the coordination of two hydrazide groups in the complex was hampered because of the polymeric nature of the ligand. It is shown that the created functionalized polyampholytes exhibit...... fungiostatic activity. The highest inhibiting effect on the growth of the pathogenic fungus Fusarium oxysporumis observed for complexes of the hydrazide-containing polyampholytes with Cu2+ ions....

  14. PHOTO-INDUCED DOPED POLYANILINE BY THE VINYLIDENE CHLORIDE AND METHYL ACRYLATE COPOLYMER AS PHOTO ACID GENERATOR

    Institute of Scientific and Technical Information of China (English)

    LI Suzhen; WAN Meixiang

    1997-01-01

    The emeraldine base form of polyaniline (PANI) can be doped by a photo-induced doping method. In this method a copolymer of vinylidene chloride and methyl acrylate (VCMAC) was used as photo acid generator which can release proton when it is exposed to ultraviolet light (λ = 254 nm). The structure of PANI-VCMAC system before and after irradiation was characterized by elemental analysis, IR, XPS, and SEM images. Results obtained indicate that the photo-induced doping characteristics, such as doping position and type of charge carriers, are similar to that of PANI doped with HCl. The poor roomtemperature conductivity (~ 10-5S/cm) of PANI-VCMAC system after irradiation may be due to low doping degree (~pH= 3) and the difference in morphology as compared with PANI-HCl film.

  15. Effects of temperature and sodium chloride concentration on the phospholipid and fatty acid compositions of a halotolerant Planococcus sp.

    Science.gov (United States)

    Miller, K J

    1985-04-01

    The phospholipid headgroup composition and fatty acid composition of a gram-positive halotolerant Planococcus sp. (strain A4a) were examined as a function of growth temperature (5 to 35 degrees C) and NaCl content (0 to 1.5 M) of the growth medium. When the growth temperature was decreased, the relative amount of mono-unsaturated branched-chain fatty acids increased. When Planococcus sp. strain A4a was grown in media containing high NaCl concentrations, the relative amount of the major fatty acid, Ca15:0, increased. The relative amount of anionic phospholipid also increased when the NaCl concentration of the growth medium was increased. The increase in anionic phospholipid content resulted from a decrease in the relative mole percent content of phosphatidylethanolamine and an increase in the relative mole percent content of cardiolipin.

  16. The development of learning media of acid-base indicator from extract of natural colorant as an alternative media in learning chemistry

    Science.gov (United States)

    Nurhadi, Mukhamad; Wirhanuddin, Erwin, Muflihah, Erika, Farah; Widiyowati, Iis Intan

    2017-03-01

    The development of learning media of acid base indicator from extract of natural colorants as an alternative media in chemistry learning; acid-base solution by using creative problem solving model at SMA N 10 Samarinda has been done. This research aimed to create and develop the learning media from extract of natural colorants, measure its quality and effectiveness, and measure the quality of student learning outcome in acid-base solution topic by using that media. The development process used Analysis, Design, Development, Implementation, and Evaluation (ADDIE) method. The learning media of acid-base indicator was created in the form of box experiment. Its quality was in the range of very good and it was effectively applied in the learning and gave positive impact on the achievement of learning goals.

  17. Suitability of peracetic acid for sterilization of media for mycoplasma cultures.

    Science.gov (United States)

    Wutzler, P; Sprössig, M; Peterseim, H

    1975-01-01

    The utility of peracetic acid for sterilization of serum and yeast extract additions to mycoplasma medium was studied by culturing six Mycoplasma species. Culture media containing additions that had been sterilized with peracetic acid proved to be as good as filtered components. The use of 0.05 to 0.1% peracetic acid is recommended to sterilize the serum and yeast extract additions since savings in time and equipment can be accomplished. PMID:1100656

  18. Environmentally safe corrosion inhibition of Mg-Al-Zn alloy in chloride free neutral solutions by amino acids

    Energy Technology Data Exchange (ETDEWEB)

    Helal, N.H. [Chemistry Department, Faculty of Science, Fayoum University, Fayoum (Egypt); Badawy, W.A., E-mail: wbadawy@cu.edu.eg [Chemistry Department, Faculty of Science, Cairo University, 12 613 Giza (Egypt)

    2011-07-30

    Highlights: > Phenyl alanine at a concentration of 2 x 10{sup -3} mol dm{sup -3} gives 93% corrosion inhibition efficiency for the corrosion of the Mg-Al-Zn alloy. > The corrosion inhibition process is based on the adsorption of the amino acid molecules on the active sites of the alloy surface by physical adsorption mechanism. > The adsorption free energy was 15.72 kJ mol{sup -1}. - Abstract: The corrosion inhibition of Mg-Al-Zn alloy was investigated in stagnant naturally aerated chloride free neutral solutions using amino acids as environmentally safe corrosion inhibitors. The corrosion rate was calculated in the absence and presence of the corrosion inhibitor using the polarization technique and electrochemical impedance spectroscopy. The experimental impedance data were fitted to theoretical data according to a proposed electronic circuit model to explain the behavior of the alloy/electrolyte interface under different conditions. The corrosion inhibition process was found to depend on the adsorption of the amino acid molecules on the metal surface. Phenyl alanine has shown remarkably high corrosion inhibition efficiency up to 93% at a concentration of 2 x 10{sup -3} mol dm{sup -3}. The corrosion inhibition efficiency was found to depend on the concentration of the amino acid and its structure. The mechanism of the corrosion inhibition process was discussed and different adsorption isotherms were investigated. The free energy of the adsorption process was calculated for the adsorption of different amino acids on the Mg-Al-Zn alloy and the obtained values reveal a physical adsorption of the inhibitor molecules on the alloy surface.

  19. Humic acid transport in saturated porous media:Influence of flow velocity and influent concentration

    Institute of Scientific and Technical Information of China (English)

    Xiaorong Wei; Mingan Shao; Lina Du; Robert Horton

    2014-01-01

    Understanding the transport of humic acids (HAs) in porous media can provide important and practical evidence needed for accurate prediction of organic/inorganic contaminant transport in different environmental media and interfaces.A series of column transport experiments was conducted to evaluate the transport of HA in different porous media at different flow velocities and influent HA concentrations.Low flow velocity and influent concentration were found to favor the adsorption and deposition of HA onto sand grains packed into columns and to give higher equilibrium distribution coefficients and deposition rate coefficients,which resulted in an increased fraction of HA being retained in columns.Consequently,retardation factors were increased and the transport of HA through the columns was delayed.These results suggest that the transport of HA in porous media is primarily controlled by the attachment of HA to the solid matrix.Accordingly,this attachment should be considered in studies of HA behavior in porous media.

  20. Humic acid transport in saturated porous media: influence of flow velocity and influent concentration.

    Science.gov (United States)

    Wei, Xiaorong; Shao, Mingan; Du, Lina; Horton, Robert

    2014-12-01

    Understanding the transport of humic acids (HAs) in porous media can provide important and practical evidence needed for accurate prediction of organic/inorganic contaminant transport in different environmental media and interfaces. A series of column transport experiments was conducted to evaluate the transport of HA in different porous media at different flow velocities and influent HA concentrations. Low flow velocity and influent concentration were found to favor the adsorption and deposition of HA onto sand grains packed into columns and to give higher equilibrium distribution coefficients and deposition rate coefficients, which resulted in an increased fraction of HA being retained in columns. Consequently, retardation factors were increased and the transport of HA through the columns was delayed. These results suggest that the transport of HA in porous media is primarily controlled by the attachment of HA to the solid matrix. Accordingly, this attachment should be considered in studies of HA behavior in porous media.

  1. Benzimidazole or Diamide From a Reaction of Diamines and Carboxylic Acids or Acid Chlorides: Crystal Structures and Theoretical Studies

    National Research Council Canada - National Science Library

    Odame, Felix; Hosten, Eric; Betz, Richard; Lobb, Kevin; Tshentu, Zenixole R

    2015-01-01

    ...-phenylenediamine in pyridine to obtain 3-methyl-N-[2-(3-methylbenzamido)phenylbenzamide (I). 2-(3-Methylphenyl)-1H-benzimidazole (II) has been obtained upon reacting o-phenylenediamine with m-toluic acid in polyphosphoric acid and toluene...

  2. N-heterocyclic carbene-assisted, bis(phosphine)nickel-catalyzed cross-couplings of diarylborinic acids with aryl chlorides, tosylates, and sulfamates.

    Science.gov (United States)

    Ke, Haihua; Chen, Xiaofeng; Zou, Gang

    2014-08-01

    Efficient bis(phosphine)nickel-catalyzed cross-couplings of diarylborinic acids with aryl chlorides, tosylates, and sulfamates have been effected with an assistance of N-heterocyclic carbene (NHC) generated in situ from N,N'-dialkylimidazoliums, e.g., N-butyl-N'-methylimidazolium bromide ([Bmim]Br), in toluene using K3PO4·3H2O as base. In contrast to bis(NHC)nickel-catalyzed conventional Suzuki coupling of arylboronic acids, mono(NHC)bis(phosphine)nickel species generated in situ from Ni(PPh3)2Cl2/[Bmim]Br displayed high catalytic activities in the cross-couplings of diarylborinic acids. The structural influences from diarylborinic acids were found to be rather small, while electronic factors from aryl chlorides, tosylates, and sulfamates affected the couplings remarkably. The couplings of electronically activated aryl chlorides, tosylates, and sulfamates could be efficiently effected with 1.5 mol % NiCl2(PPh3)2/[Bmim]Br as catalyst precursor to give the biaryl products in excellent yields, while 3-5 mol % loadings had to be used for the couplings of non- and deactivated ones. A small ortho-substitutent on the aromatic ring of aryl chlorides, tosylates, and sulfamates was tolerable. Applicability of the nickel-catalyzed cross-couplings in practical synthesis of fine chemicals has been demonstrated in process development for a third-generation topical retinoid, Adapalene.

  3. Corrosion Inhibition of Aluminium by Capparis deciduas in Acidic Media

    Directory of Open Access Journals (Sweden)

    P. Arora

    2007-01-01

    Full Text Available The inhibition efficiency of ethanolic extract of different parts of Capparis deciduas (Ker in acidic medium has been evaluated by mass loss and thermometric methods. Values of inhibition efficiency obtained from the two methods are in good agreement and are dependent upon the concentration of inhibitor and acid.

  4. Sodium Chloride Diffusion in Low-Acid Foods during Thermal Processing and Storage.

    Science.gov (United States)

    Bornhorst, Ellen R; Tang, Juming; Sablani, Shyam S

    2016-05-01

    This study aimed at modeling sodium chloride (NaCl) diffusion in foods during thermal processing using analytical and numerical solutions and at investigating the changes in NaCl concentrations during storage after processing. Potato, radish, and salmon samples in 1% or 3% NaCl solutions were heated at 90, 105, or 121 °C for 5 to 240 min to simulate pasteurization and sterilization. Selected samples were stored at 4 or 22 °C for up to 28 d. Radish had the largest equilibrium NaCl concentrations and equilibrium distribution coefficients, but smallest effective diffusion coefficients, indicating that a greater amount of NaCl diffused into the radish at a slower rate. Effective diffusion coefficients determined using the analytical solution ranged from 0.2 × 10(-8) to 2.6 × 10(-8) m²/s. Numerical and analytical solutions showed good agreement with experimental data, with average coefficients of determination for samples in 1% NaCl at 121 °C of 0.98 and 0.95, respectively. During storage, food samples equilibrated to a similar NaCl concentration regardless of the thermal processing severity. The results suggest that sensory evaluation of multiphase (solid and liquid) products should occur at least 14 d after processing to allow enough time for the salt to equilibrate within the product. © 2016 Institute of Food Technologists®

  5. Cellulose pretreatment with 1-n-butyl-3-methylimidazolium chloride for solid acid-catalyzed hydrolysis.

    Science.gov (United States)

    Kim, Soo-Jin; Dwiatmoko, Adid Adep; Choi, Jae Wook; Suh, Young-Woong; Suh, Dong Jin; Oh, Moonhyun

    2010-11-01

    This study has been focused on developing a cellulose pretreatment process using 1-n-butyl-3-methylimidazolium chloride ([bmim]Cl) for subsequent hydrolysis over Nafion(R) NR50. Thus, several pretreatment variables such as the pretreatment period and temperature, and the [bmim]Cl amount were varied. Additionally, the [bmim]Cl-treated cellulose samples were characterized by X-ray diffraction analysis, and their crystallinity index values including CI(XD), CI(XD-CI) and CI(XD-CII) were then calculated. When correlated with these values, the concentrations of total reducing sugars (TRS) obtained by the pretreatment of native cellulose (NC) and glucose produced by the hydrolysis reaction were found to show a distinct relationship with the [CI(NC)-CI(XD)] and CI(XD-CII) values, respectively. Consequently, the cellulose pretreatment step with [bmim]Cl is to loosen a crystalline cellulose through partial transformation of cellulose I to cellulose II and, furthermore, the TRS release, while the subsequent hydrolysis of [bmim]Cl-treated cellulose over Nafion(R) NR50 is effective to convert cellulose II to glucose. Copyright 2010 Elsevier Ltd. All rights reserved.

  6. Reactivity of NaCl with Secondary Organic Acids: An Important Mechanism of the Chloride Depletion in Sea Salt Particles Mixed with Organic Materials

    Science.gov (United States)

    Wang, B.; Laskin, A.; Kelly, S.; Gilles, M. K.; Shilling, J. E.; Zelenyuk, A.; Wilson, J. M.; Tivanski, A.

    2012-12-01

    Sea salt particles, one of the major sources of atmospheric aerosols, undergo complex multi-phase reactions and have profound consequences on their physical and chemical properties, thus on climate. Depletion of chloride in sea salt particles was reported in previous field studies and was attributed to the acid displacement of sea salt chlorides with inorganic acids, such as nitric and sulfuric acids. Some studies have also showed that the chloride deficit cannot be fully compensated for this mechanism. We present an important pathway contributing to this chloride depletion: reactions of weak organic acids with sea salt particles. NaCl particles internally mixed with secondary organic materials generated from the reactions of limonene and alpha-pinene with ozone served as surrogates for sea salt particles mixed with organic materials. Chemical imaging analysis of these particles was conducted using complementary techniques including computer controlled scanning electron microscopy with energy dispersive analysis of X-rays (CCSEM/EDX), scanning transmission X-ray microscopy with near edge X-ray absorption fine structure spectroscopy (STXM/NEXAFS), and micro-fourier transform infrared spectroscopy (micro-FTIR). Substantial chloride depletion and formation of organic salts were observed along with distinctive changes in particle morphology after hydration/dehydration processes. The results indicate that secondary organic acids can effectively react with NaCl particles resulting in displacement of chloride and release of gaseous HCl. This is consistent with a recent field study showing chloride depletion in sea salt particles mixed with organic materials which cannot be fully compensated by inorganic acid displacement. Although the formation of the organic salts is not thermodynamically favored in bulk aqueous solution, these reactions are driven by the high volatility and evaporation of gaseous HCl in particles, especially during hydration/dehydration processes. The

  7. Iridium-based double perovskites for efficient water oxidation in acid media

    Science.gov (United States)

    Diaz-Morales, Oscar; Raaijman, Stefan; Kortlever, Ruud; Kooyman, Patricia J.; Wezendonk, Tim; Gascon, Jorge; Fu, W. T.; Koper, Marc T. M.

    2016-08-01

    The development of active, cost-effective and stable oxygen-evolving catalysts is one of the major challenges for solar-to-fuel conversion towards sustainable energy generation. Iridium oxide exhibits the best available compromise between catalytic activity and stability in acid media, but it is prohibitively expensive for large-scale applications. Therefore, preparing oxygen-evolving catalysts with lower amounts of the scarce but active and stable iridium is an attractive avenue to overcome this economical constraint. Here we report on a class of oxygen-evolving catalysts based on iridium double perovskites which contain 32 wt% less iridium than IrO2 and yet exhibit a more than threefold higher activity in acid media. According to recently suggested benchmarking criteria, the iridium double perovskites are the most active catalysts for oxygen evolution in acid media reported until now, to the best of our knowledge, and exhibit similar stability to IrO2.

  8. Electrophysiological characterization of ivermectin triple actions on Musca chloride channels gated by l-glutamic acid and γ-aminobutyric acid.

    Science.gov (United States)

    Fuse, Toshinori; Kita, Tomo; Nakata, Yunosuke; Ozoe, Fumiyo; Ozoe, Yoshihisa

    2016-10-01

    Ivermectin (IVM) is a macrocyclic lactone that exerts antifilarial, antiparasitic, and insecticidal effects on nematodes and insects by acting on l-glutamic acid-gated chloride channels (GluCls). IVM also acts as an allosteric modulator of various other ion channels. Although the IVM binding site in the Caenorhabditis elegans GluCl was identified by X-ray crystallographic analysis, the mechanism of action of IVM in insects is not well defined. We therefore examined the action of IVM on the housefly (Musca domestica) GluCl and γ-aminobutyric acid (GABA)-gated ion channel (GABACl). For both channels, IVM induced currents by itself, potentiated currents induced by low concentrations of agonists, and inhibited currents induced by high concentrations of agonists. Despite exerting common actions on both types of channels, GluCls were more susceptible to IVM actions than GABACls, indicating that GluCls are the primary target of IVM. Substitution of an amino acid residue in the third transmembrane segment (G312M in GluCls, and G333A and G333M in GABACls) resulted in significantly reduced levels or loss of activation, potentiation, and antagonism of the channels, indicating that these three actions result from the interaction of IVM with amino acid residues in the transmembrane intersubunit crevice. Copyright © 2016 Elsevier Ltd. All rights reserved.

  9. Transient increase in neuronal chloride concentration by neuroactive amino acids released from glioma cells

    Directory of Open Access Journals (Sweden)

    Cristina eBertollini

    2012-11-01

    Full Text Available Neuronal chloride concentration ([Cl-]i is known to be dynamically modulated and alterations in Cl- homeostasis may occur in the brain at physiological and pathological conditions, being also likely involved in glioma-related seizures. However, the mechanism leading to changes in neuronal [Cl-]i during glioma invasion are still unclear. To characterize the potential effect of glioma released soluble factors on neuronal [Cl-]i, we used genetically encoded CFP/YFP-based ratiometric Cl-Sensor transiently expressed in cultured hippocampal neurons. Exposition of neurons to glioma conditioned medium (GCM caused rapid and transient elevation of [Cl-]i, resulting in the increase of fluorescence ratio, which was strongly reduced by blockers of ionotropic glutamate receptors APV and NBQX. Furthermore, in HEK cells expressing GluR1-AMPA receptors, GCM activated ionic current with efficacy similar to those caused by glutamate, supporting the notion that GCM contains glutamate or glutamatergic agonists, which cause neuronal depolarization, activation of NMDA and AMPA/KA receptors leading to elevation of [Cl-]i. Chromatographic analysis of the GCM showed that it contained several aminoacids, including glutamate, whose release from glioma cells did not occur via the most common glial mechanisms of transport, or in response to hypoosmotic stress. GCM also contained glycine, whose action contrasted the glutamate effect. Indeed, strychnine application significantly increased GCM-induced depolarization and [Cl-]i rise. GCM-evoked [Cl-]i elevation was not inhibited by antagonists of Cl- transporters and significantly reduced in the presence of anion channels blocker NPPB, suggesting that Cl-selective channels are a major route for GCM-induced Cl- influx. Altogether, these data show that glioma released aminoacids may dynamically alter Cl- equilibrium in surrounding neurons, deeply interfering with their inhibitory balance, likely leading to physiological and

  10. Ternary choline chloride/caffeic acid/ethylene glycol deep eutectic solvent as both a monomer and template in a molecularly imprinted polymer.

    Science.gov (United States)

    Fu, Najing; Liu, Xiao; Li, Liteng; Tang, Baokun; Row, Kyung Ho

    2017-05-01

    A molecularly imprinted polymer based on a ternary deep eutectic solvent comprised of choline chloride/caffeic acid/ethylene glycol was prepared. The caffeic acid in the ternary deep eutectic solvent was used as both a monomer and template. The molecularly imprinted polymer based on the ternary deep eutectic solvent was characterized by Fourier transform infrared spectroscopy, thermogravimetric analysis, field-emission scanning electron microscopy, Brunauer-Emmett-Teller surface area analysis, atomic force microscopy, and elemental analysis. A series of molecularly imprinted polymers based on choline chloride/caffeic acid/ethylene glycol with different molar ratios was prepared and applied to the molecular recognition of polyphenols. A comparison of the recognition ability of molecularly imprinted polymers to polyphenols revealed that the choline chloride/caffeic acid/ethylene glycol (1:0.4:1, molar ratio) molecularly imprinted polymer had the best molecular recognition effect with 132 μg/g of protocatechuic acid, 104 μg/g of catechins, 80 μg/g of epicatechin, and 123 μg/g of caffeic acid in 6 h, as well as good molecular recognition ability for polyphenols from a Radix Asteris sample. These results show that the ternary deep eutectic solvent based molecularly imprinted polymer is a potential medium that can be applied to drug purification, drug delivery, and drug analysis. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  11. Electrocatalytic oxidation of formic acid by poly(diallyldimethylammonium chloride) and Pt/Pd-functionalized carbon nanotubes mixtures.

    Science.gov (United States)

    Kim, Min-Su; Kim, Daekun; Lee, Hyo Kyoung; Jeon, Seungwon

    2012-12-01

    Improving the catalytic activity of the anode catalyst is an important task in the direct formic acid fuel cell (DFAFC). In this study, the catalysts were prepared by dispersing either platinum or palladium metal on the surface of thiolated multi-walled carbon nanotubes (t-MWCNTs), denoted as t-MWCNT-Pt and t-MWCNT-Pd, respectively. These modified t-MWCNT and poly(diallyldimethylammonium chloride) (PDDA) were ultrasonically mixed and loading on a glassy carbon electrode (GCE) for formic acid (FA) oxidation and the catalytic activities were then investigated by using cyclic voltammetry (CV) and chronoamperometry (CA) methods. The as-formed catalysts were characterized by several methods. To optimize the catalytic performance, we investigated the catalysts separately and together (in different ratios) for FA oxidation. The PDDA mixed catalyst demonstrated a slightly better performance. These results indicated that the PDDA/(t-MWCNT-Pt + t-MWCNT-Pd) catalyst exhibited better activity than that of the corresponding other catalysts.

  12. Aqueous citric acid as green reaction media for the synthesis of octahydroxanthenes

    Directory of Open Access Journals (Sweden)

    Camilo A. Navarro D.

    2013-08-01

    Full Text Available A simple, convenient and environmentally friendly one-pot procedure for the synthesis of 1,8-dioxo-octahydroxanthenes by the reaction of dimedone and aromatic aldehydes in aqueous citric acid is described. In this green synthetic protocol promoted by the reaction media, the use of any other catalysts and hazardous organic solvents are avoided, making the work up procedure greener and easier. The isolation of the products, obtained in good yields, is readily performed by filtration and crystallization from ethanol when required and the aqueous acidic media can be easily recycled and reused several times without significant loss of catalytic activity.

  13. Polymerization of 10,16-dihydroxyhexadecanoic acid, main monomer of tomato cuticle, using the Lewis acidic ionic liquid choline chloride.2ZnCl2

    Directory of Open Access Journals (Sweden)

    Mayra Beatriz eGómez-Patiño

    2015-11-01

    Full Text Available 10,16-dihydroxyhexadecanoic acid, main monomer of the tomato cuticle obtained from agro-residual wastes, was polymerized using (choline chloride.2ZnCl2 ionic liquid as catalyst at three different temperatures (80, 90 and 100 °C. The resulting polyesters obtained under these conditions were insoluble in most of the organic solvents and showed different physicochemical properties. While at 80 °C polymers were obtained as powder, at higher temperature they were found in viscous consistency. According with the CP MAS 13C NMR and FTIR-ATR analysis, polymers showed a linear structure with an increasing degree of esterification in position C-10. Polyesters were analyzed by means of differential scanning calorimetry (DSC, atomic force microscopy (AFM and X ray diffraction (small- and wide-angle scattering, SWAXS techniques.

  14. A study of the IR spectra of the copigments of malvin chloride with organic acids

    Directory of Open Access Journals (Sweden)

    ZORAN P. NEDIC

    2001-07-01

    Full Text Available The infrared spectra of the copigments of malvin with several organic acids: caffeic, ferulic, sinapic, chlorogenic, and tannic, were analyzed in order to elucidate the bonding of the molecules in the copigments. It was established that copigmentation is realized through hydrogen bonding between malvin molecules and the acids under study. The infrared spectra reveal that two groups of hydrogen bonds are formed, which include interactions of different molecular structures: hydroxy groups (bands around 3500 cm–1 and oxonium ions of the molecules (bands below 3000 cm–1. The formed hydrogen bonds were found to be of different strengths. The strengths of the hydrogen bonds were tentatively correlated with thermodynamic properties of the corresponding copigmentation reactions.

  15. Immune response and disease resistance of calves fed chromium nicotinic acid complex or chromium chloride.

    Science.gov (United States)

    Kegley, E B; Spears, J W; Brown, T T

    1996-07-01

    Twenty-one Holstein bull calves (skinfold thickness after an intradermal injection of phytohemagglutinin were measured to evaluate cell-mediated immune response. Calves supplemented with Cr-nicotinic acid complex had a greater response than did controls at 6, 12, 24, and 48 h after injection. Calves supplemented with CrCl3 had a greater response than did controls at 24 and 48 h after injection. In vitro blastogenic responses of lymphocytes to phytohemagglutinin or pokeweed mitogen and antibody response to porcine red blood cells were not affected by treatment. Following a disease challenge with an intranasal dose of infectious bovine rhinotracheitis on d 75, body temperature tended to be lower for calves supplemented with Cr-nicotinic acid complex than for control calves. Calves supplemented with either Cr source had lower serum cortisol concentrations at 5 d after challenge. Chromium supplementation enhanced cell-mediated immune function.

  16. Bis(imidazolium) salts derived from amino acids as receptors and transport agents for chloride anions

    NARCIS (Netherlands)

    González-Mendoza, Laura; Altava, Belén; Burguete, M.I.; Escorihuela, Jorge; Hernando, Elsa; Luis, S.V.; Quesada, Roberto; Vicent, Cristian

    2015-01-01

    The binding properties of bis(imidazolium) hosts 1a-c derived from amino acids towards different anions have been studied by 1H NMR titration experiments in 95:05 CD3CN:H2O at 303 K, ESI-MS and theoretical calculations. Among this family, the salt 1c showed a stro

  17. Extraction of gold, palladium, and platinum from acidic media with cyclic sulfoxide derivative

    Institute of Scientific and Technical Information of China (English)

    Songping Wu; Guobang Gu

    2007-01-01

    The extraction of gold (Ⅲ), palladium (Ⅱ), and platinum (Ⅳ) from the acidic media with the cyclic sulfoxide derivative of a-dodecyl-tetrahydrothiophene 1-oxide (dtmso) was investigated. Gold (Ⅲ), palladium (Ⅱ), and platinum (Ⅳ) could be separated from the acidic media with suitable sulfoxide concentration and acidity. The extraction reaction of gold (Ⅲ), palladium (Ⅱ) or platinum (Ⅳ) is exothermic when dtmso is used as an extracting reagent. The coordination number was studied by the slope method. The results indicate that, in high acidity, the dtmso coordination number for extracting gold (Ⅲ) or palladium (Ⅱ) is 3, and that for platinum (Ⅳ) is 2. UV and FT-IR spectra were used to analyze the structure of the complex. Gold (Ⅲ) is coordinated with the oxygen atom in S=O group in dtmso, and palladium (Ⅱ) or platinum (Ⅳ) is coordinated with the sulfur atom in S=O group in dtmso.

  18. Mechanism of interaction of niflumic acid with heterologously expressed kidney CLC-K chloride channels.

    Science.gov (United States)

    Picollo, Alessandra; Liantonio, Antonella; Babini, Elena; Camerino, Diana Conte; Pusch, Michael

    2007-04-01

    CLC-K Cl(-) channels belong to the CLC protein family. In kidney and inner ear, they are involved in transepithelial salt transport. Mutations in ClC-Kb lead to Bartter's syndrome, and mutations in the associated subunit barttin produce Bartter's syndrome and deafness. We have previously found that 3-phenyl-CPP blocks hClC-Ka and rClC-K1 from the extracellular side in the pore entrance. Recently, we have shown that niflumic acid (NFA), a nonsteroidal anti-inflammatory fenamate, produces biphasic behavior on human CLC-K channels that suggests the presence of two functionally different binding sites: an activating site and a blocking site. Here, we investigate in more detail the interaction of NFA on CLC-K channels. Mutants that altered block by 3-phenyl-2-(p-chlorophenoxy)propionic acid (CPP) had no effect on NFA block, indicating that the inhibition binding site of NFA is different from that of 3-phenyl-CPP and flufenamic acid. Moreover, NFA does not compete with extracellular Cl(-) ions, suggesting that the binding sites of NFA are not located deep in the pore. Differently from ClC-Ka, on the rat homologue ClC-K1, NFA has only an inhibitory effect. We developed a quantitative model to describe the complex action of NFA on ClC-Ka. The model predicts that ClC-Ka possesses two NFA binding sites: when only one site is occupied, NFA increases ClC-Ka currents, whereas the occupation of both binding sites leads to channel block.

  19. Inhibiting Effects of Rabeprazole Sulfide on the Corrosion of Mild Steel in Acidic Chloride Solution

    Directory of Open Access Journals (Sweden)

    M. K. Pavithra

    2013-01-01

    Full Text Available The corrosion inhibition effect of Rabeprazole sulfide (RS on mild steel in 1 M hydrochloric acid (HCl was investigated using weight loss, potentiodynamic polarization, electrochemical impedance spectroscopy (EIS, and chronoamperometric measurements. Protection efficiency of RS increases with the concentration and decreases with the rise in temperature. Adsorption of RS on mild steel surface in 1 M HCl follows Langmuir adsorption isotherm. The kinetic and thermodynamic parameters governing the adsorption process were calculated and discussed. The polarization results suggest that RS performed as an excellent mixed-type inhibitor for mild steel corrosion in 1 M HCl.

  20. Leaching of copper concentrates with high arsenic content in chlorine-chloride media; Lixiviacion de concentrados de cobre con alto contenido de arsenico en medio cloro-cloruro

    Energy Technology Data Exchange (ETDEWEB)

    Herreros, O.; Fuentes, G.; Quiroz, R.; Vinals, J.

    2003-07-01

    This work reports the results of copper concentrates leaching which have high arsenic concepts (up to 2.5%). The treatments were carried out using chlorine that forms from sodium hypochlorite and sulphuric acid. The aim of this work is to obtain a solution having high copper content 4 to 6 g/l and 5 to 7 g/l free acid in order to submit it directly to a solvent extraction stage. In addition, this solution should have minimum content of arsenic and chloride ions. To carry out this investigation, an acrylic reactor was constructed where the leaching tests were made at constant temperature in a thermostatic bath under atmospheric pressure. The concentrate samples were obtained from mineral processing plants from Antofagasta, Chile. Typical variables were studied, such as leaching agent concentration, leaching time, pulp density and temperature among others. Some of the residues were analyzed by XRD and EPS. On the other hand, the solutions were analyzed by Atomic Absorption Spectroscopy. The results indicate solutions having the contents stated above can be obtained. (Author) 19 refs.

  1. Development and validation of dissolution testings in acidic media for rabeprazole sodium delayed-release capsules.

    Science.gov (United States)

    Tan, Yinhe; Si, Xiaoqing; Zhong, Lulu; Feng, Xin; Yang, Xinmin; Huang, Min; Wu, Chuanbin

    2016-10-01

    Rabeprazole sodium (RAB) dissolved in acidic media is accompanied by its degradation in the course of dissolution testing. To develop and establish the accumulative release profiles of ACIPHEX(®) Sprinkle (RAB) delayed-release capsules (ACIPHEX(®) Sprinkle) in acidic media using USP apparatus 2 (paddle apparatus) as a dissolution tester, the issues of determination of accumulative release amount of RAB in these acidic media and interference of hydroxypropylmethyl cellulose phthalate were solved by adding appropriate hydrochloric acid (HCl) into dissolution samples coupled with centrifugation so as to remove the interference and form a solution of degradation products of RAB, which is of a considerably stable ultraviolet (UV) absorbance at the wavelength of 298 nm within 2.0 h. Therefore, the accumulative release amount of RAB in dissolution samples at each sample time points could be determined by UV-spectrophotometry, and the accumulative release profiles of ACIPHEX(®) Sprinkle in the media of pH 1.0, pH 6.0, and pH 6.8 could be established. The method was validated per as the ICH Q2 (R1) guidelines and demonstrated to be adequate for quality control of ACIPHEX(®) Sprinkle and the accumulative release profiles can be used as a tool to guide the formulation development and quality control of a generic drug for ACIPHEX(®) Sprinkle.

  2. 3—Mercaptopropionic Acid Capped Gold Nanoclusters:Quantized Capacitance in Aquesous Media

    Institute of Scientific and Technical Information of China (English)

    李迪; 李景虹

    2003-01-01

    3-Mercaptopropionic acid monolayer protected gold nanoclusters (MPA-MPCs) were synthesized and characterized by transmission electorn microscopy,UV-Vis spectroscopy,X-ray photoelectron spectroscopy and Fourler transform infrared spectroscopy.The exact value of quantized double-layer capacitance of MPCs in aqueous media was obtained by differential pulse voltammograms.

  3. Failure of multi-layer graphene coatings in acidic media

    DEFF Research Database (Denmark)

    Yu, Feng; Stoot, Adam Carsten; Bøggild, Peter

    2016-01-01

    with thick, high-quality chemical vapor deposited multilayered graphene is exposed to acidic solutions, a dramatic evolution of gas is observed at the coating–substrate interface. The gas bubbles grow and merge, eventually rupturing and delaminating the coating. This behavior, attributed to cathodic hydrogen...... evolution, can also occur spontaneously on a range of other technologically important metals and alloys based on iron, zinc, aluminum and manganese; this makes these findings relevant for practical applications of graphene-based coatings.Being impermeable to all gases, graphene has been proposed...... is exposed to acidic solutions, a dramatic evolution of gas is observed at the coating–substrate interface. The gas bubbles grow and merge, eventually rupturing and delaminating the coating. This behavior, attributed to cathodic hydrogen evolution, can also occur spontaneously on a range of other...

  4. Monitoring of the fermentation media of citric acid by the trimethylsilyl derivatives of the organic acids formed.

    Science.gov (United States)

    Ghassempour, Alireza; Nojavan, Saeed; Talebpour, Zahra; Amiri, Ali Asghar; Najafi, Nahid Mashkouri

    2004-10-20

    In this approach, a derivatization method is described for monitoring of organic acids in fermentation media without any separation step. The aqueous phase of fermentation media was evaporated and heated in a silylation reagent to form trimethylsilyl (TMS) derivatives. The silylated compounds are analyzed by 29Si nuclear magnetic resonance (29Si NMR) and gas chromatography-mass spectrometry (GC-MS). 29Si NMR can qualitatively monitor the components produced in the Krebs cycle. Quantification of these compounds is investigated by using selected ion monitoring mode of mass spectrometry. In this mode, mass to charge (m/z) values of their [M - 15]+ ions, which are 465, 275, 247, 221, 335, 251, and 313 of TMS derivatives of citric, alpha-ketoglutaric, succinic, fumaric, l-malic, oxaloacetic, and palmitic (as an internal standard), acids, respectively, are used. The limit of detection and the linear working range for derivatized citric acid were found to be 0.1 mg L(-1) and 10-3 x 10(4) mg L(-1). The relative standard deviation of the method for five replicates was 2.1%. The average recovery efficiency for citric acid added to culture media was approximately 97.2%. Quantitative results of GC-MS are compared with those obtained by an ultraviolet-visible method. Copyright 2004 American Chemical Society

  5. Efficient hydrolysis of cellulose over a magnetic lignin-derived solid acid catalyst in 1-butyl-3-methylimidazolium chloride

    Energy Technology Data Exchange (ETDEWEB)

    Hu, Lei; Wu, Zhen; Xu, Jiaxing; Zhou, Shouyong; Tang, Guodong [Huaiyin Normal University, Huaian (China)

    2016-04-15

    A green and efficient strategy for the hydrolysis of cellulose was developed by using a magnetic lignin-derived solid acid catalyst (MLC-SO{sub 3}H) in the presence of ionic liquid 1-butyl-3-methylimidazolium chloride ([BMIM]Cl). The results indicated that reaction temperature, reaction time, catalyst loading and water content have a big influence on the yield of total reducing sugars (TRS). By optimizing these reaction parameters, 69.3% TRS yield was observed at 140 .deg. C for 150 min with the addition of 40 wt% MLC-SO{sub 3}H and 1 wt% water. More importantly, MLC-SO{sub 3}H could be easily separated from the reaction mixture with an external magnet and could be repeatedly used five times without an obvious loss of catalytic activity, demonstrating that it possessed excellent recyclability. Furthermore, a plausible mechanism involving three consecutive processes of dissolution, adsorption and catalysis for the hydrolysis of cellulose in [BMIM]Cl over a catalyst of MLC-SO{sub 3}H was also proposed.

  6. Electrolytic regeneration of acid cupric chloride printed circuit board etchant. Final report, August 1, 1995--October 31, 1996

    Energy Technology Data Exchange (ETDEWEB)

    Oxley, J.E.; Smialek, R.J.

    1997-04-18

    The overall objective of this ERIP program was to make substantial progress in further developing a process for electrolytic regeneration of acid cupric chloride etchant - a process which was initially demonstrated in in-house studies and EPA Phase I and Phase II SBIRs. Specific objectives of the work were: (1) to define optimum system operating conditions by conducting a systematic study of process parameters, (2) to develop or find a superior electrolyic cell separator material, (3) to determine an optimum activation procedure for the flow-through carbon/graphite felt electrodes which are so critical to process performance, (4) to demonstrate - on the pre-prototype scale - electrolytic compensation for oxygen ingress - which causes etchant solution growth, and (5) to begin engineering design work on a prototype-scale regeneration unit. Parametric studies looked at the effect that key plating parameters have on copper deposit quality. Parameters tested included (a) velocity past the plating cathodes, (b) copper concentration in the catholyte solution from which the copper is being plated, (c) plating current density, and (d) catholyte cupric ion concentration. The most significant effects were obtained for velocity changes. The work showed that catholyte velocities above 0.5 ft/sec were needed to get adequate plating at 77.5 mA/cm{sup 2} and higher currents, and that even higher flow was better.

  7. Genoprotective effect of hyaluronic acid against benzalkonium chloride-induced DNA damage in human corneal epithelial cells

    Science.gov (United States)

    Wu, Han; Zhang, Huina; Wang, Changjun; Wu, Yihua; Xie, Jiajun; Jin, Xiuming; Yang, Jun

    2011-01-01

    Purpose The aim of this study was to investigate hyaluronic acid (HA) protection on cultured human corneal epithelial cells (HCEs) against benzalkonium chloride (BAC)-induced DNA damage and intracellular reactive oxygen species (ROS) increase. Methods Cells were incubated with different concentrations of BAC with or without the presence of 0.2% HA for 30 min. DNA damage to HCEs was examined by alkaline comet assay and by immunofluorescence microscopic detection of the phosphorylated form of histone variant H2AX (γH2AX) foci. ROS production was assessed by the fluorescent probe, 2',7'-dichlorodihydrofluorescein diacetate (DCFH-DA). Cell apoptosis was determined with annexin V staining by flow cytometry. Results HA significantly reduced BAC-induced DNA damage as indicated by the tail length (TL) and tail moment (TM) of alkaline comet assay and by γH2AX foci formation, respectively. Moreover, HA significantly decreased BAC-induced ROS increase and cell apoptosis. However, exposure to HA alone did not produce any significant change in DNA damage, ROS generation, or cell apoptosis. Conclusions BAC could induce DNA damage and cell apoptosis in HCEs, probably through increasing oxidative stress. Furthermore, HA was an effective protective agent that had antioxidant properties and could decrease DNA damage and cell apoptosis induced by BAC. PMID:22219631

  8. Kinetic and equilibrium studies of the removal of cadmium ions from acidic chloride solutions by hydrophobic pyridinecarboxamide extractants

    Energy Technology Data Exchange (ETDEWEB)

    Borowiak-Resterna, Aleksandra [Institute of Chemical Technology and Engineering, Poznan University of Technology, Pl. Marii Sklodowskiej-Curie 2, 60-965 Poznan (Poland); Cierpiszewski, Ryszard [Poznan University of Economics, Faculty of Commodity Science, al. Niepodleglosci 10, 61-875 Poznan (Poland); Prochaska, Krystyna, E-mail: Krystyna.Prochaska@put.poznan.pl [Institute of Chemical Technology and Engineering, Poznan University of Technology, Pl. Marii Sklodowskiej-Curie 2, 60-965 Poznan (Poland)

    2010-07-15

    Liquid-liquid extraction of cadmium(II) from acidic chloride solutions was carried out with alkyl derivatives of pyridinecarboxamide in toluene with addition of 2-ethylhexan-1-ol as modifier. Equilibrium as well as kinetic studies was performed. The kinetic studies of a Cd(II) extraction process were carried out with a Lewis cell having a constant interfacial area. Cadmium(II) concentration in the aqueous phases was determined by atomic absorption spectroscopy (Varian SPECTR AA800). The results of equilibrium experiments showed that cadmium(II) was quantitatively extracted with N,N-dihexylpyridine-3-carboxamide whereas the derivative N,N-dihexylpyridine-2-carboxamide was not able to transfer Cd(II) ions from the aqueous phase to the organic one. Thus, the kinetics of extraction and the initial extraction rate were examined only in the systems with N,N-dihexylpyridine-3-carboxamide. The obtained experimental data as well as the calculated values of mass transfer coefficients suggest that the investigated process of extraction of Cd(II) by means of pyridinecarboxamide as extractant occurs in the mixed diffusion-kinetic region. Moreover, the results of adsorption studies indicated that the extraction of Cd(II) with a hydrophobic extractant should be considered as an interfacial process.

  9. A new dioxime corrosion inhibitor for the protection and conservation of copper: synthesis, characterization and evaluation in acidic chloride solution

    Science.gov (United States)

    Abu-Baker, Ahmad N.; Al-Qudah, Mahmoud A.

    2016-08-01

    This study aimed to investigate a new dioxime compound as a corrosion inhibitor for copper. The compound (4,6-dihydroxy benzene-1,3-dicarbaldehyde dioxime) was synthesized and characterized by nuclear magnetic resonance spectroscopy. Electrochemical impedance spectroscopy and potentiodynamic polarization measurements were used to compare the dioxime compound with benzotriazole for their effectiveness as corrosion inhibitors for copper in 0.1 M HCl solution. Fourier transform infrared (FTIR) spectroscopy and scanning electron microscopy (SEM) were used to investigate the bonding mechanisms and morphological changes of the two inhibitors on the copper surface. The electrochemical techniques showed that the new dioxime compound was more effective than benzotriazole in inhibiting copper corrosion in the acidic chloride medium. The FTIR and SEM results indicated that the dioxime compound was able to coordinate with copper ions and formed a protective film on the copper surface. It was concluded that the new dioxime compound proved effectiveness to be used as a corrosion inhibitor for the protection and conservation of copper.

  10. Electrochemical properties and stress corrosion cracking of alloys 600, 690, and 800 in solutions containing boric acid and chloride

    Energy Technology Data Exchange (ETDEWEB)

    Bae, J. H.; Won, C. H. [Chungnam Nation Univ., Taejon (Korea, Republic of); Lee, E. H.; Kim, H. P.; Kim, W. C. [KAERI, Taejon (Korea, Republic of)

    2000-10-01

    Electrochemical characteristics and stress corrosion cracking(SCC)of Alloy 600, Alloy 690 and Alloy 800 have been studied in boric acid solution with chloride. Electrochemical characteristics were measured in mixed solution of 3% H{sub 3}BO{sub 3} and 0.2g/l Cl{sup -} at 320 .deg. C. SCC resistance was predicted with Parameter(P{sub SCC}) including current density ratio obtained at two different scan rates. P{sub SCC} increased with a following sequence: Alloy 600MA, 600TT, 690TT and Alloy 800. SCC test was carried out with C-ring specimens and reverse U-bend(RUB) specimens at 320 .deg. C and 350 .deg. C. Test solutions were mixture of 3% H{sub 3}BO{sub 3} and 0.2g/l Cl{sup -} at 320 .deg. C and mixture of 27% H{sub 3}BO{sub 3} and 2g/l Cl{sup -} at 350 .deg. C. C-ring specimens test in the solution of 3% H{sub 3}BO{sub 3} and 0.2g/l Cl{sup -} at 320 .deg. C for 2400hrs did not show SCC. RUB specimen of Alloy600MA and 600TT showed SCC after 1920 hours exposure to the solution of 27% H{sub 3}BO{sub 3} and 0.2g/l Clat 350 .deg. C.

  11. Removal of phosphorus from agricultural wastewaters using adsorption media prepared from acid mine drainage sludge

    Science.gov (United States)

    Sibrell, Philip L.; Montgomery, Gary A.; Ritenour, Kelsey L.; Tucker, Travis W.

    2009-01-01

    Excess phosphorus in wastewaters promotes eutrophication in receiving waterways. A??cost-effective method for the removal of phosphorus from water would significantly reduce the impact of such wastewaters on the environment. Acid mine drainage sludge is a waste product produced by the neutralization of acid mine drainage, and consists mainly of the same metal hydroxides used in traditional wastewater treatment for the removal of phosphorus. In this paper, we describe a method for the drying and pelletization of acid mine drainage sludge that results in a particulate media, which we have termed Ferroxysorb, for the removal of phosphorus from wastewater in an efficient packed bed contactor. Adsorption capacities are high, and kinetics rapid, such that a contact time of less than 5 min is sufficient for removal of 60-90% of the phosphorus, depending on the feed concentration and time in service. In addition, the adsorption capacity of the Ferroxysorb media was increased dramatically by using two columns in an alternating sequence so that each sludge bed receives alternating rest and adsorption cycles. A stripping procedure based on treatment with dilute sodium hydroxide was also developed that allows for recovery of the P from the media, with the possibility of generating a marketable fertilizer product. These results indicate that acid mine drainage sludges - hitherto thought of as undesirable wastes - can be used to remove phosphorus from wastewater, thus offsetting a portion of acid mine drainage treatment costs while at the same time improving water quality in sensitive watersheds.

  12. Crystal growth of semiorganic complex- samarium chloride coordinated thiourea-L-tartaric acid and its studies on structure and optical characteristics

    Science.gov (United States)

    Slathia, Goldy; Singh, Harjinder; Ramya, E.; Rao, D. Narayana; Bamzai, K. K.

    2017-05-01

    The semi-organic complex of samarium chloride coordinated thiourea-L-tartaric acid (SCTLT) has been grown as a single crystal by slow evaporation technique at room temperature. For structural studies, the grown crystal was subjected to single crystal X-ray diffraction and Fourier transform infra-red (FTIR) spectroscopy. Low cut off wavelength and transparent characteristics were explored by UV-VIS optical characterization. Third-order nonlinear optical properties of grown crystal were investigated by Z-scan technique.

  13. FOLIAR APPLICATION OF CALCIUM AND BORON-BASED CALCIUM CHLORIDE AND BORIC ACID MIXED ON INCOME TANK FOR THE EVALUATION OF SOYBEAN SEED.

    OpenAIRE

    Arantes, Rafael Pereira; Faculdade Dr. Francisco Maeda; Cury, Tadeu Nascimento; Faculdade Dr. Francisco Maeda; Leão, Fabiana De Paula; Universidade Federal de Viçosa; Maciel Junior,Vinicius Antonio

    2009-01-01

    The experiment was conducted in the municipality of Ituverava, in the Estiva farm in the agricultural year of 07/08. The work used the soybean cultivar BRS Valiosa RR to evaluate the performace of the soybean with application of calcium chloride to 26% and boric acid to 17% in different stages of development of culture. The treatments consisted of applications in eight steps, as follows: pre-bloom, pre-bloom + flowering, pre-bloom + flowering + pod, pre - bloom + pod, bloomed, flowering ...

  14. Antimicrobial Efficacy of a Sulfuric Acid and Sodium Sulfate Blend, Peroxyacetic Acid, and Cetylpyridinium Chloride against Salmonella on Inoculated Chicken Wings.

    Science.gov (United States)

    Scott, Brittney R; Yang, Xiang; Geornaras, Ifigenia; Delmore, Robert J; Woerner, Dale R; Reagan, James O; Morgan, J Brad; Belk, Keith E

    2015-11-01

    Studies were conducted to evaluate the efficacy of a commercial blend of sulfuric acid and sodium sulfate (SSS) in reducing Salmonella on inoculated whole chilled chicken wings and to compare its efficacy to peroxyacetic acid (PAA) and cetylpyridinium chloride (CPC). Wings were spot inoculated (5 to 6 log CFU/ml of sample rinsate) with a five-strain mixture of novobiocin- and nalidixic acid-resistant Salmonella and then left untreated (control) or treated by immersing individual wings in 350 ml of antimicrobial solution. An initial study evaluated two treatment immersion times, 10 and 20 s, of SSS (pH 1.1) and compared cell recoveries following rinsing of treated samples with buffered peptone water or Dey/Engley neutralizing broth. In a second study, inoculated wings were treated with SSS (pH 1.1; 20 s), PAA (700 ppm, 20 s), or CPC (4,000 ppm, 10 s) and analyzed for survivors immediately after treatment (0 h) and after 24 h of aerobic storage at 4°C. Color and pH analyses were also conducted in the latter study. Recovery of Salmonella survivors following treatment with SSS (10 or 20 s) was not (P ≥ 0.05) affected by the type of cell recovery rinse solution (buffered peptone water or Dey/Engley neutralizing broth), but there was an effect (P Salmonella at 0 h increased in the order CPC , SSS , PAA; however, after 24 h of aerobic storage, pathogen counts of SSS- and PAA-treated wings did not differ (P ≥ 0.05). Overall, the results indicated that SSS applied at pH 1.1 for 20 s was an effective antimicrobial intervention to reduce Salmonella contamination on chicken wings.

  15. Zeolite molecular sieves have dramatic acid-base effects on enzymes in nonaqueous media.

    Science.gov (United States)

    Fontes, Nuno; Partridge, Johann; Halling, Peter J; Barreiros, Susana

    2002-02-05

    Zeolite molecular sieves very commonly are used as in situ drying agents in reaction mixtures of enzymes in nonaqueous media. They often affect enzyme behavior, and this has been interpreted in terms of altered hydration. Here, we show that zeolites can also have dramatic acid-base effects on enzymes in low water media, resulting from their cation-exchange ability. Initial rates of transesterification catalyzed by cross-linked crystals of subtilisin were compared in supercritical ethane, hexane, and acetonitrile with water activity fixed by pre-equilibration. Addition of zeolite NaA (4 A powder) still caused remarkable rate enhancements (up to 20-fold), despite the separate control of hydration. In the presence of excess of an alternative solid-state acid-base buffer, however, zeolite addition had no effect. The more commonly used Merck molecular sieves (type 3 A beads) had similar but somewhat smaller effects. All zeolites have ion-exchange ability and can exchange H+ for cations such as Na+ and K+. These exchanges will tend to affect the protonation state of acidic groups in the protein and, hence, enzymatic activity. Zeolites pre-equilibrated in aqueous suspensions of varying pH-pNa gave very different enzyme activities. Their differing basicities were demonstrated directly by equilibration with an indicator dissolved in toluene. The potential of zeolites as acid-base buffers for low-water media is discussed, and their ability to overcome pH memory is demonstrated.

  16. Chloride-inducible transient apoplastic alkalinizations induce stomata closure by controlling abscisic acid distribution between leaf apoplast and guard cells in salt-stressed Vicia faba.

    Science.gov (United States)

    Geilfus, Christoph-Martin; Mithöfer, Axel; Ludwig-Müller, Jutta; Zörb, Christian; Muehling, Karl H

    2015-11-01

    Chloride stress causes the leaf apoplast transiently to alkalize, an event that is presumed to contribute to the ability of plants to adapt to saline conditions. However, the initiation of coordinated processes downstream of the alkalinization is unknown. We hypothesize that chloride-inducible pH dynamics are a key chemical feature modulating the compartmental distribution of abscisic acid (ABA) and, as a consequence, affecting stomata aperture. Apoplastic pH and stomata aperture dynamics in intact Vicia faba leaves were monitored by microscopy-based ratio imaging and porometric measurements of stomatal conductance. ABA concentrations in leaf apoplast and guard cells were compared with pH dynamics by gas-chromatography-mass-spectrometry (GC-MS) and liquid-chromatography-tandem-mass spectrometry (LC-MS/MS). Results demonstrate that, upon chloride addition to roots, an alkalizing factor that initiates the pH dynamic propagates from root to leaf in a way similar to xylem-distributed water. In leaves, it induces a systemic transient apoplastic alkalinization that causes apoplastic ABA concentration to increase, followed by an elevation of endogenous guard cell ABA. We conclude that the transient alkalinization, which is a remote effect of chloride stress, modulates the compartmental distribution of ABA between the leaf apoplast and the guard cells and, in this way, is instrumental in inducing stomata closure during the beginning of salinity.

  17. Microwave and infrared spectra, adjusted r0 structural parameters, conformational stabilities, vibrational assignments, and theoretical calculations of cyclobutylcarboxylic acid chloride.

    Science.gov (United States)

    Klaassen, Joshua J; Darkhalil, Ikhlas D; Deodhar, Bhushan S; Gounev, Todor K; Gurusinghe, Ranil M; Tubergen, Michael J; Groner, Peter; Durig, James R

    2013-08-01

    The FT-microwave spectrum of cyclobutylcarboxylic acid chloride, c-C4H7C(O)Cl, has been recorded and 153 transitions for the (35)Cl and (37)Cl isotopologues have been assigned for the gauche-equatorial (g-Eq) conformation. The ground state rotational constants were determined for (35)Cl [(37)Cl]: A = 4349.8429(25) [4322.0555(56)] MHz, B = 1414.8032(25) [1384.5058(25)] MHz, and C = 1148.2411(25) [1126.3546(25)] MHz. From these rotational constants and ab initio predicted parameters, adjusted r0 parameters are reported with distances (Å) rCα-C = 1.491(4), rC═O = 1.193(3), rCα-Cβ = 1.553(4), rCα-Cβ' = 1.540(4), rCγ-Cβ = 1.547(4), rCγ-Cβ' = 1.546(4), rC-Cl = 1.801(3) and angles (deg) τCγCβCβ'Cα = 30.9(5). Variable temperature (-70 to -100 °C) infrared spectra (4000 to 400 cm(-1)) were recorded in liquid xenon and the g-Eq conformer was determined the most stable form, with enthalpy differences of 91 ± 9 cm(-1) (1.09 ± 0.11 kJ/mol) for the gauche-axial (g-Ax) form and 173 ± 17 cm(-1) (2.07 ± 0.20 kJ/mol) for the trans-equatorial (t-Eq) conformer. The relative amounts at ambient temperature are 54% g-Eq, 35 ± 1% g-Ax, and 12 ± 1% t-Eq forms. Vibrational assignments have been provided for the three conformers and theoretical calculations were carried out. The results are discussed and compared to corresponding properties of related molecules.

  18. Analysis of amino acids by HPLC/electrospray negative ion tandem mass spectrometry using 9-fluorenylmethoxycarbonyl chloride (Fmoc-Cl) derivatization.

    Science.gov (United States)

    Ziegler, Jörg; Abel, Steffen

    2014-12-01

    A new method for the determination of amino acids is presented. It combines established methods for the derivatization of primary and secondary amino groups with 9-fluorenylmethoxycarbonyl chloride (Fmoc-Cl) with the subsequent amino acid specific detection of the derivatives by LC-ESI-MS/MS using multiple reaction monitoring (MRM). The derivatization proceeds within 5 min, and the resulting amino acid derivatives can be rapidly purified from matrix by solid-phase extraction (SPE) on HR-X resin and separated by reversed-phase HPLC. The Fmoc derivatives yield several amino acid specific fragment ions which opened the possibility to select amino acid specific MRM transitions. The method was applied to all 20 proteinogenic amino acids, and the quantification was performed using L-norvaline as standard. A limit of detection as low as 1 fmol/µl with a linear range of up to 125 pmol/µl could be obtained. Intraday and interday precisions were lower than 10 % relative standard deviations for most of the amino acids. Quantification using L-norvaline as internal standard gave very similar results compared to the quantification using deuterated amino acid as internal standards. Using this protocol, it was possible to record the amino acid profiles of only a single root from Arabidopsis thaliana seedlings and to compare it with the amino acid profiles of 20 dissected root meristems (200 μm).

  19. [Makeup of free intracellular amino acids in Cunninghamella elegans growing on media with hydrocarbons].

    Science.gov (United States)

    Kazanskaia, T B; Lieh Ts'ui Lin; Bekhtereva, M N

    1975-01-01

    The rate of growth of Cunninghamella elegans (--) 1204 is higher on a mineral medium with glucose (6.56 g/litre) than on a mineral medium containing undecane, tridecane, and pentadecane (0.72--0.87 g/litre); all glutamic acid is consumed only from the medium with glucose. The cells contain 15--16 free amino acids and 1--2 amides, glutamic and aspartic acids and alanine prevailing. The culture grown on the medium with glucose contains asparagine, and the cells cultivated on the medium with alkanes contain histidine. Non-proteinogenous aminobutyric acids were found in the pool of the cells grown on all tested media with an exception of the medium containing undecane.

  20. Preliminary treatment of chlorinated streams containing fission products: mechanisms leading to crystalline phases in molten chloride media; Pretraitement pyrochimique de flux charges en produits de fission: mecanismes conduisant a l'obtention de phases cristallines en milieux chlorures fondus

    Energy Technology Data Exchange (ETDEWEB)

    Hudry, D

    2008-10-15

    The world of the nuclear power gets ready for profound modifications so that 'the atom' can aspire in conformance with long-lasting energy: it is what we call the development of generation IV nuclear systems. So, the new pyrochemical separation processes for the spent fuel reprocessing are currently being investigated. Techniques in molten chloride media generate an ultimate flow (with high chlorine content) which cannot be incorporated in conventional glass matrices. This flow is entirely water-soluble and must be conditioned in a chemical form which is compatible with a long-term disposal. This work of thesis consists in studying new ways for the management of the chlorinated streams loaded with fission products (FP). To do it, a strategy of selective FP extraction via the in situ formation of crystalline phases was retained. The possibility of extracting rare earths in the eutectic LiCl-KCl was demonstrated via the development of a new way of synthesis of rare earth phosphates (TRPO{sub 4}). As regards alkaline earths, the conversion of strontium and barium chlorides to the corresponding tungstates or molybdates was studied in different solvents. Mechanisms leading to the crystalline phases in molten chloride media were studied via the coupling of NMR and XRD techniques. First of all, it has been shown that these mechanisms are dependent on the stability of the used precursors. So in the case of the formation of rare earth phosphates the solvent is chemically active. On the other hand, in the case of the formation of alkaline earth tungstates it would seem that the solvent plays the role of structuring agent which can control the ability to react of chlorides. (author)

  1. Brönsted Acidic Ionic Liquid 1-(1-Propylsulfonic-3-methylimidazolium-Chloride Catalyzed Hydrolysisof D-Cellobiose in Aqueous Medium

    Directory of Open Access Journals (Sweden)

    Ananda S. Amarasekara

    2012-01-01

    Full Text Available Brönsted acidic ionic liquid 1-(1-propylsulfonic-3-methylimidazolium chloride (PSMIMCl shows a higher catalytic activity than sulfuric acid in the hydrolysis of D-cellobiose to D-glucose in water at 90–120°C. This catalytic activity enhancement is more significant at higher temperatures, and at 120°C, PSMIMCl produced 64.5% glucose yield, whereas H2SO4 produced only 42.2% after 40 min. reaction, and this is a 52.8% enhancement of catalytic activity due to the alkylimidazolium group attached to the sulfonic acid group. 1H NMR monitoring of the D-cellobiose hydrolysis in PSMIMCl and sulfuric acid mediums failed to reveal intermediates in the hydrolysis reaction, and this is probably due to rapid conversion of the intermediate(s to a mixture of D-glucose anomers with α:β≈1:1.6.

  2. Scorpion ethanol extract and valproic acid effects on hippocampal glial fibrillary acidic protein expression in a rat model of chronic-kindling epilepsy induced by lithium chloride-pilocarpine

    Institute of Scientific and Technical Information of China (English)

    Yi Liang; Hongbin Sun; Liang Yu; Baoming He; Yan Xie

    2012-01-01

    The present study analyzed the effects of ethanol extracts of scorpion on epilepsy prevention and hippocampal expression of glial fibrillary acidic protein in a lithium chloride-pilocarpine epileptic rat model. Results were subsequently compared with valproic acid. Results showed gradually-increased hippocampal glial fibrillary acidic protein expression following model establishment; glial fibrillary acidic protein mRNA expression was significantly increased at 3 days, reached a peak at 7 days, and then gradually decreased thereafter. Ethanol extracts of scorpion doses of 580 and 1 160 mg/kg, as well as 120 mg/kg valproic acid, led to a decreased number of glial fibrillary acidic protein-positive cells and glial fibrillary acidic protein mRNA expression, as well as decreased seizure grades and frequency of spontaneously recurrent seizures. The effects of 1 160 mg/kg ethanol extracts of scorpion were equal to those of 120 mg/kg valproic acid. These results suggested that the anti-epileptic effect of ethanol extracts of scorpion were associated with decreased hippocampal glial fibrillary acidic protein expression in a rat model of lithium chloride-pilocarpine induced epilepsy.

  3. Action of niflumic acid on evoked and spontaneous calcium-activated chloride and potassium currents in smooth muscle cells from rabbit portal vein.

    Science.gov (United States)

    Hogg, R. C.; Wang, Q.; Large, W. A.

    1994-01-01

    1. The action of niflumic acid was studied on spontaneous and evoked calcium-activated chloride (ICl(Ca)) and potassium (IK(Ca)) currents in rabbit isolated portal vein cells. 2. With the nystatin perforated patch technique in potassium-containing solutions at a holding potential of -77 mV (the potassium equilibrium potential), niflumic acid produced a concentration-dependent inhibition of spontaneous transient inward current (STIC, calcium-activated chloride current) amplitude. The concentration to reduce the STIC amplitude by 50% (IC50) was 3.6 x 10(-6) M. 3. At -77 mV holding potential, niflumic acid converted the STIC decay from a single exponential to 2 exponential components. In niflumic acid the fast component of decay was faster, and the slow component was slower than the control decay time constant. Increasing the concentration of niflumic acid enhanced the decay rate of the fast component and reduced the decay rate of the slow component. 4. The effect of niflumic acid on STIC amplitude was voltage-dependent and at -50 and +50 mV the IC50 values were 2.3 x 10(-6) M and 1.1 x 10(-6) M respectively (cf. 3.6 x 10(-6) M at -77 mV). 5. In K-free solutions at potentials of -50 mV and +50 mV, niflumic acid did not induce a dual exponential STIC decay but just increased the decay time constant at both potentials in a concentration-dependent manner. 6. Niflumic acid, in concentrations up to 5 x 10(-5) M, had no effect on spontaneous calcium-activated potassium currents.(ABSTRACT TRUNCATED AT 250 WORDS) PMID:7921628

  4. Uric acid, carotid intima-media thickness and body composition in prepubertal children.

    Science.gov (United States)

    Bassols, J; Martínez-Calcerrada, J M; Prats-Puig, A; Carreras-Badosa, G; Díaz-Roldán, F; Osiniri, I; Riera-Pérez, E; de Zegher, F; Ibáñez, L; López-Bermejo, A

    2016-10-01

    Increased uric acid is an independent biomarker for cardiovascular disease in obese adolescents and adults. We investigated whether uric acid relates to carotid intima-media thickness (cIMT) in prepubertal children, and whether body mass index (BMI) and preperitoneal fat modulate this association. 359 asymptomatic prepubertal Caucasian children were stratified according to BMI categories (171 with BMI-SDS 50th centile). Uric acid levels, insulin resistance (homeostasis model assessment insulin resistance; HOMA-IR), C-reactive protein (CRP), triacylglycerol (TG), systolic blood pressure (SBP), abdominal fat and cIMT (both by ultrasound) were assessed. Uric acid was associated with several cardiovascular risk factors, namely higher HOMA-IR, CRP, TG, BMI, waist, SBP, preperitoneal fat and cIMT (all P uric acid and cIMT (both P uric acid was preferentially related to cIMT in heavier children (β = 0.247, P uric acid is associated with cIMT in asymptomatic prepubertal children. Both higher BMI and preperitoneal fat aggravate the potential risk of atherosclerotic disease imposed by higher concentrations of uric acid. © 2015 World Obesity.

  5. Optimization of culture media for enhancing gamma-linolenic acid production by Mucor hiemalis

    Directory of Open Access Journals (Sweden)

    Mina Mohammadi Nasr

    2016-03-01

    Full Text Available Introduction: g-linolenic acid is an essential fatty acid in human nutrition. In the present study, production of g-linolenic acid by Mucor hiemalis PTCC 5292 was evaluated in submerged fermentation. Materials and methods: The fermentation variables were chosen according to the fractional factorial design and further optimized via full factorial method. Four significant variables, glucose, peptone, ammonium nitrate and pH were selected for the optimization studies. The design consisted of total 16 runs consisting of runs at two levels for each factor with three replications of the center points. Results: The analysis of variance and three-dimensional response surface plot of effects indicated that variables were regarded to be significant for production of g-linolenic acid by Mucor hiemalis. Results indicated that fermentation at the optimum conditions (100 g/l glucose concentration; 1 g/l peptone; 1 g/l ammonium nitrate, and pH of 4.5 enhanced the g-linolenic acid production up to 709 mg/l. Discussion and conclusion: The results of this study indicated that higher g-linolenic acid yield can be achieved in a simple medium at high glucose and ammonium nitrate, low peptone concentrations and acidic pH by Mucor hiemalis PTCC 5292. This simple and low cost optimization condition of culture media can be applied for g-linolenic acid production at higher scale for pharmaceutical and nutritional industries. 

  6. Evaluating Potential Bias in Media Coverage of the Public Debate over Acid Rain and Chlorofluorocarbons in the 1980s

    Science.gov (United States)

    Williams, Tiffany Dawn; Moore, Rebecca; Markewitz, Daniel

    2012-01-01

    This study evaluates media coverage of two important environmental issues from the 1980s (acid rain and chlorofluorocarbons), providing historical context for current media coverage analysis. Focusing on popular magazine articles, this study identifies key characteristics of content and presentation. Content-related characteristics are inclusion…

  7. Evaluating Potential Bias in Media Coverage of the Public Debate over Acid Rain and Chlorofluorocarbons in the 1980s

    Science.gov (United States)

    Williams, Tiffany Dawn; Moore, Rebecca; Markewitz, Daniel

    2012-01-01

    This study evaluates media coverage of two important environmental issues from the 1980s (acid rain and chlorofluorocarbons), providing historical context for current media coverage analysis. Focusing on popular magazine articles, this study identifies key characteristics of content and presentation. Content-related characteristics are inclusion…

  8. Application of cyanuric chloride-based six new chiral derivatizing reagents having amino acids and amino acid amides as chiral auxiliaries for enantioresolution of proteinogenic amino acids by reversed-phase high-performance liquid chromatography.

    Science.gov (United States)

    Bhushan, Ravi; Dixit, Shuchi

    2012-04-01

    Six dichloro-s-triazine (DCT) reagents having L-Leu, D-Phg, L-Val, L-Met, L-Ala and L-Met-NH(2) as chiral auxiliaries in cyanuric chloride were introduced for enantioseparation of 13 proteinogenic amino acids. Four other DCTs and six monochloro-s-triazine (MCT) reagents having amino acid amides as chiral auxiliaries were also synthesized. These 16 chiral derivatizing reagents (CDRs) were used for synthesis of diastereomers of all the 13 analytes using microwave irradiation, which were resolved by reversed-phase high-performance liquid chromatography (RP-HPLC) using C18 column and gradient eluting mixture of aqueous TFA and acetonitrile with UV detection at 230 nm. It required only 60-90 s for derivatization using microwave irradiation. Better resolution and lower retention times were observed for the diastereomers prepared with CDRs having amino acids as chiral auxiliaries as compared to counterparts prepared with reagents having amino acid amides as chiral auxiliaries. As the best resolution of all the 13 analytes was observed for their diastereomers prepared using the DCT reagent having L-Leu as chiral auxiliary, this CDR was further employed for derivatization of Lys, Tyr, His and Arg followed by RP-HPLC analysis of resulting diastereomers. The results are discussed in light of acid and amide groups of chiral auxiliaries constituting CDRs, electronegativities of the atoms of achiral moieties constituting CDRs and hydrophobicities of side chains of amino acids constituting CDRs and analytes.

  9. The Oxidation of Ascorbic Acid by Hexacyanoferrate(III) Ion in Acidic Aqueous Media.

    Science.gov (United States)

    Martins, Luis J. A.; da Costa, J. Barbosa

    1988-01-01

    Describes a kinetic and mechanistic investigation of ascorbic acid by a substitution-inert complex in acidic medium suitable for the undergraduate level. Discusses obtaining the second order rate constant for the rate determining step at a given temperature and comparison with the value predicted on the basis of the Marcus cross-relation. (CW)

  10. Lipase catalyzed synthesis of organic acid esters of lactic acid in non-aqueous media.

    Science.gov (United States)

    Kiran, K R; Divakar, S

    2001-05-04

    Lipases from Rhizomucor miehei (Lipozyme IM20) and porcine pancreas (PPL) were employed as catalysts for the esterification reaction between the hydroxyl group of lactic acid and the carboxyl group of organic acids. Reactions were carried out at both shake-flask and bench-scale levels. Various parameters, such as solvent, temperature, substrate and enzyme concentrations, effect of buffer volume, buffer pH and water volume, were investigated for optimization of yields. While ethylmethyl ketone (EMK) was found to be the best solvent for shake-flask reactions, chloroform gave higher yields at bench-scale level. Detailed studies were carried out with respect to the synthesis of palmitoyl and stearoyl lactic acids. At shake-flask level, maximum yields of 37.5 and 40% were observed in case of palmitoyl and stearoyl lactic acids, respectively, with Lipozyme IM20; at bench-scale level, the maximum yields were 85.1 and 99% respectively, when PPL was employed. Of all the organic acids employed (C(2)--C(18)), only lauric, palmitic and stearic acids gave yields above 50%. At bench-scale level, PPL could be reused for up to three cycles with yields above 40%. Esters prepared were found to conform to Food Chemical Codex (FCC) specifications in terms of acid value, ester value, sodium and lactic acid contents.

  11. Corrosion Inhibition of AISI 316L and Modified-AISI 630 Stainless Steel by the New Organic Inhibitor [(CH32N]3PSe in Chloride Media:Electrochemical and Physical Study

    Directory of Open Access Journals (Sweden)

    Yafa ZARGOUNI

    2015-04-01

    Full Text Available We evaluate the effect of the Tris-dimethylaminoselenophosphoramide (SeAPon the corrosion inhibition of modified-AISI 630 and AISI 316L stainless steel (SS in 3 wt. % NaCl. The electrochemical behaviors of tested SS samples are investigated before and after adding the Seep into the chloride media by potentiodynamic polarization technique. The adsorption of SeAP onto both SS surfaces is verified by global discharge optical emission spectroscopy (GDOES.  SeAP is found to be a good inhibitor for SS corrosion, especially when added at a concentration of 0.5 wt. %.

  12. The rare earth element geochemistry of acid-sulphate and acid-sulphate-chloride geothermal systems from Yellowstone National Park, Wyoming, USA

    Science.gov (United States)

    Lewis, Anita J.; Palmer, Martin R.; Sturchio, Neil C.; Kemp, Anthony J.

    1997-02-01

    Rare earth element (REE) concentrations have been determined by Inductively Coupled Plasma-Mass Spectrometry (ICP-MS) in acid-sulphate and acid-sulphate-chloride waters and the associated sinters and volcanic rocks from the Yellowstone National Park (YNP), Wyoming, USA, geothermal system. REE concentrations in the volcanic rocks range from 222 to 347 ppm; their chondite-normalised REE patterns are typical of upper continental crust, with LREE > HREE and negative Eu anomalies. Total REE concentrations in the fluids range from 3 to 1133 nmol kg -1 (≥ 162 ppm), and ΣREE concentrations in sinter are ≥ 181 ppm. REE abundances and patterns in drill core material from YNP indicate some REE mobility. Normalisation of REE concentrations in altered Lava Creek Tuff (LCT) from Y-12 drill core to REE concentrations in fresh LCT indicate that the REE overall have been depleted with the exception of Eu, which has been decoupled from the REE series and concentrated in the altered rocks. Relative to the host rocks the REE patterns of the fluids are variably depleted in HREEs and LREEs, and usually have a pronounced positive Eu anomaly. This decoupling of Eu from the REE suite suggests that (1) Eu has been preferentially removed either from the host rock glass or from the host rock minerals, or (2) the waters are from a high temperature or reducing environment where Eu 2+ is more soluble than the trivalent REEs. Since the latter is inconsistent with production of acid-sulphate springs in a low temperature, oxidising near-surface environment, we suggest that the positive Eu anomalies in the fluids result from preferential dissolution of a Eu-rich phase in the host rock. Spatial and temporal variations in major element chemistry and pH of the springs sampled from Norris Geyser Basin and Crater Hills accompany variations in REE concentrations and patterns of individual geothermal springs. These are possibly related to changes in subsurface plumbing, which results in variations in

  13. Poly(acrylic acid) coating induced 2-line ferrihydrite nanoparticle transport in saturated porous media

    Science.gov (United States)

    Xiang, Aishuang; Yan, Weile; Koel, Bruce E.; Jaffé, Peter R.

    2013-07-01

    Iron oxide and iron nanoparticles (NPs) have been used effectively for environmental remediation, but are limited in their applications by strong retention in groundwater-saturated porous media. For example, delivery of NPs to large groundwater reservoirs would require large numbers of injection wells. To address this problem, we have explored polymer coatings as a surface engineering strategy to enhance transport of oxide nanoparticles in porous media. We report here on our studies of 2-line ferrihydrite NPs and the influence of poly (acrylic acid) (PAA) polymer coatings on the colloidal stability and transport in natural sand-packed column tests simulating flow in groundwater-saturated porous media. Measurements were also made of zeta potential, hydrodynamic diameter, and polymer adsorption and desorption properties. The coated NPs have a diameter range of 30-500 nm. We found that NP transport was improved by PAA coating and that the transport properties could be tuned by adjusting the polymer concentration. Our results demonstrate that a high stability of oxide particles and improved transport can be achieved in groundwater-saturated porous media by introducing negatively charged polyelectrolytes and optimizing polymer concentrations.

  14. Poly(acrylic acid) coating induced 2-line ferrihydrite nanoparticle transport in saturated porous media

    Energy Technology Data Exchange (ETDEWEB)

    Xiang, Aishuang [Princeton University, Chemical and Biological Engineering Department (United States); Yan, Weile [Texas Tech University, Civil and Environmental Engineering (United States); Koel, Bruce E., E-mail: bkoel@princeton.edu [Princeton University, Chemical and Biological Engineering Department (United States); Jaffe, Peter R., E-mail: jaffe@princeton.edu [Princeton University, Civil and Environmental Engineering Department (United States)

    2013-07-15

    Iron oxide and iron nanoparticles (NPs) have been used effectively for environmental remediation, but are limited in their applications by strong retention in groundwater-saturated porous media. For example, delivery of NPs to large groundwater reservoirs would require large numbers of injection wells. To address this problem, we have explored polymer coatings as a surface engineering strategy to enhance transport of oxide nanoparticles in porous media. We report here on our studies of 2-line ferrihydrite NPs and the influence of poly (acrylic acid) (PAA) polymer coatings on the colloidal stability and transport in natural sand-packed column tests simulating flow in groundwater-saturated porous media. Measurements were also made of zeta potential, hydrodynamic diameter, and polymer adsorption and desorption properties. The coated NPs have a diameter range of 30-500 nm. We found that NP transport was improved by PAA coating and that the transport properties could be tuned by adjusting the polymer concentration. Our results demonstrate that a high stability of oxide particles and improved transport can be achieved in groundwater-saturated porous media by introducing negatively charged polyelectrolytes and optimizing polymer concentrations.

  15. Recovery of lactic acid from simultaneous saccharification and fermentation media using anion exchange resins.

    Science.gov (United States)

    Moldes, A B; Alonso, J L; Parajó, J C

    2003-07-01

    The physicochemical properties (capacity, kinetics and selectivity) of the ion exchange resins Amberlite IRA900, IRA400, IRA96 and IRA67 were determined to evaluate their comparative suitability for lactic acid recovery. Both the kinetics of lactic acid sorption from aqueous solutions and the equilibrium were assessed using mathematical models, which provided a close interpretation of the experimental results. The best resins (Amberlite IRA96 and IRA67) were employed in further fixed-bed operation using aqueous lactic acid solutions as feed. In this set of experiments, parameters such as capacity, regenerant consumption, percentage of lactic acid recovery and product concentration were measured. Amberlite IRA67, a weak base resin, was selected for lactic acid recovery from SSF (simultaneous saccharification and fermentation) broths. Owing to the presence of nutrients and ions other than lactate, a slightly decreased capacity was determined when using SSF media instead aqueous lactic acid solutions, but quantitative lactic acid recoveries at constant capacities were obtained in four sequential load/regeneration cycles.

  16. Suitable combination of promoter and micellar catalyst for kilo fold rate acceleration on benzaldehyde to benzoic acid conversion in aqueous media at room temperature: a kinetic approach.

    Science.gov (United States)

    Ghosh, Aniruddha; Saha, Rumpa; Ghosh, Sumanta K; Mukherjee, Kakali; Saha, Bidyut

    2013-05-15

    The kinetics of oxidation of benzaldehyde by chromic acid in aqueous and aqueous surfactant (sodium dodecyl sulfate, SDS, alkyl phenyl polyethylene glycol, Triton X-100 and N-cetylpyridinium chloride, CPC) media have been investigated in the presence of promoter at 303 K. The pseudo-first-order rate constants (kobs) were determined from a logarithmic plot of absorbance as a function time. The rate constants were found to increase with introduction of heteroaromatic nitrogen base promoters such as Picolinic acid (PA), 2,2'-bipyridine (bipy) and 1,10-phenanthroline (phen). The product benzoic acid has been characterized by conventional melting point experiment, NMR, HRMS and FTIR spectral analysis. The mechanism of both unpromoted and promoted reaction path has been proposed for the reaction. In presence of the anionic surfactant SDS, cationic surfactant CPC and neutral surfactant TX-100 the reaction can undergo simultaneously in both aqueous and micellar phase with an enhanced rate of oxidation in the micellar phase. Both SDS and TX-100 produce normal micellar effect whereas CPC produce reverse micellar effect in the presence of benzaldehyde. The observed net enhancement of rate effects has been explained by considering the hydrophobic and electrostatic interaction between the surfactants and reactants. SDS and bipy combination is the suitable one for benzaldehyde oxidation.

  17. Evaluation of Deoxyribonucleic Acid Toxicity Induced by the Radiopharmaceutical 99mTechnetium-Methylenediphosphonic Acid and by Stannous Chloride in Wistar Rats

    Directory of Open Access Journals (Sweden)

    Adriano Caldeira-de-Araujo

    2012-11-01

    Full Text Available Radiopharmaceuticals are employed in patient diagnostics and disease treatments. Concerning the diagnosis aspect, technetium-99m (99mTc is utilized to label radiopharmaceuticals for single photon computed emission tomography (SPECT due to its physical and chemical characteristics. 99mTc fixation on pharmaceuticals depends on a reducing agent, stannous chloride (SnCl2 being the most widely-utilized. The genotoxic, clastogenic and anegenic properties of the 99mTc-MDP(methylene diphosphonate used for bone SPECT and SnCl2 were evaluated in Wistar rat blood cells using the Comet assay and micronucleus test. The experimental approach was to endovenously administer NaCl 0.9% (negative control, cyclophosphamide 50 mg/kg b.w. (positive control, SnCl2 500 μg/mL or 99mTc-MDP to animals and blood samples taken immediately before the injection, 3, and 24 h after (in the Comet assay and 36 h after, for micronucleus test. The data showed that both SnCl2 and 99mTc-MDP-induced deoxyribonucleic acid (DNA strand breaks in rat total blood cells, suggesting genotoxic potential. The 99mTc-MDP was not able to induce a significant DNA strand breaks increase in in vivo assays. Taken together, the data presented here points to the formation of a complex between SnCl2 in the radiopharmaceutical 99mTc-MDP, responsible for the decrease in cell damage, compared to both isolated chemical agents. These findings are important for the practice of nuclear medicine.

  18. Effect of chloride ion on the kinetics and mechanism of the reaction between chlorite ion and hypochlorous acid.

    Science.gov (United States)

    Kormányos, Balázs; Nagypál, István; Peintler, Gábor; Horváth, Attila K

    2008-09-01

    The effect of chloride ion on the chlorine dioxide formation in the ClO 2 (-)-HOCl reaction was studied by following .ClO 2 concentration spectrophotometrically at pH 5-6 in 0.5 M sodium acetate. On the basis of the earlier experimental data collected without initially added chloride and on new experiments, the earlier kinetic model was modified and extended to interpret the two series of experiments together. It was found that the chloride ion significantly increases the initial rate of .ClO 2 formation. At the same time, the .ClO 2 yield is increased in HOCl but decreased in ClO 2 (-) excess by the increase of the chloride ion concentration. The two-step hydrolysis of dissolved chlorine through Cl 2 + H 2O left harpoon over right harpoon Cl 2OH (-) + H (+) and Cl 2OH (-) left harpoon over right harpoon HOCl + Cl (-) and the increased reactivity of Cl 2OH (-) compared to HOCl are proposed to explain these phenomena. It is reinforced that the hydrolysis of the transient Cl 2O 2 takes place through a HOCl-catalyzed step instead of the spontaneous hydrolysis. A seven-step kinetic model with six rate parameters (constants and/or ratio of constants) is proposed on the basis of the rigorous least-squares fitting of the parameters simultaneously to 129 absorbance versus time curves measured up to approximately 90% conversion. The advantage of this method of evaluation is briefly outlined.

  19. Absorption, fluorescence, and acid-base equilibria of rhodamines in micellar media of sodium dodecyl sulfate

    Science.gov (United States)

    Obukhova, Elena N.; Mchedlov-Petrossyan, Nikolay O.; Vodolazkaya, Natalya A.; Patsenker, Leonid D.; Doroshenko, Andrey O.; Marynin, Andriy I.; Krasovitskii, Boris M.

    2017-01-01

    Rhodamine dyes are widely used as molecular probes in different fields of science. The aim of this paper was to ascertain to what extent the structural peculiarities of the compounds influence their absorption, emission, and acid-base properties under unified conditions. The acid-base dissociation (HR+ ⇄ R + H+) of a series of rhodamine dyes was studied in sodium n-dodecylsulfate micellar solutions. In this media, the form R exists as a zwitterion R±. The indices of apparent ionization constants of fifteen rhodamine cations HR+ with different substituents in the xanthene moiety vary within the range of pKaapp = 5.04 to 5.53. The distinct dependence of emission of rhodamines bound to micelles on pH of bulk water opens the possibility of using them as fluorescent interfacial acid-base indicators.

  20. Direct synthesis of formic acid from carbon dioxide by hydrogenation in acidic media.

    Science.gov (United States)

    Moret, Séverine; Dyson, Paul J; Laurenczy, Gábor

    2014-06-02

    The chemical transformation of carbon dioxide into useful products becomes increasingly important as CO2 levels in the atmosphere continue to rise as a consequence of human activities. In this article we describe the direct hydrogenation of CO2 into formic acid using a homogeneous ruthenium catalyst, in aqueous solution and in dimethyl sulphoxide (DMSO), without any additives. In water, at 40 °C, 0.2 M formic acid can be obtained under 200 bar, however, in DMSO the same catalyst affords 1.9 M formic acid. In both solvents the catalysts can be reused multiple times without a decrease in activity. Worldwide demand for formic acid continues to grow, especially in the context of a renewable energy hydrogen carrier, and its production from CO2 without base, via the direct catalytic carbon dioxide hydrogenation, is considerably more sustainable than the existing routes.

  1. 3-phenyl-4-acyl-5-isoxazolones as reagents for liquid-liquid extraction of tetravalent zirconium and hafnium from acidic chloride solutions

    OpenAIRE

    Reddy,B. Ramachandra; Kumar,J. Rajesh; Reddy,A. Varada

    2006-01-01

    Liquid liquid extraction of tetravalent zirconium and hafnium from acidic chloride solutions has been investigated using 3-phenyl-4-acyl-5-isoxazolones in xylene such as 3-phenyl-4-benzoyl-5-isoxazolones (HPBI), 3-phenyl-4-(4-fluorobenzoyl)-5-isoxazolone (HFBPI) and 3-phenyl-4-(4-toluoyl)-5-isoxazolone (HTPI). The extraction of zirconium(IV) / hafnium(IV) shows a ion exchange mechanism: MO2+ (aq) + 2 HA (org) « MOA2 (org) + 2 H+(aq), where M = Zr(IV) / Hf(IV) and HA = HPBI or HFBPI or H...

  2. Synergistic inhibition of kale seed germination by coumarin and (2-chloroethyl)-trimethylammonium chloride, and its reversal by kinetin and gibberellic acid.

    Science.gov (United States)

    Knypl, J S

    1966-09-01

    1. The retarding effect of (2-chloroethyl)trimethylammonium chloride (CCC) on germination of kale seeds is reduced and overcome by either kinetin or gibberellic acid (GA). 2. Coumarin inhibition of germination is reduced by kinetin but not by GA. 3. Germination of seeds treated with coumarin in combination with CCC is blocked; both kinetin and GA reduce the synergistic, inhibitory effect of coumarin and CCC. It is suggested that coumarin and CCC block alternative metabolic pathways which lead to germination in kale seed; these pathways are directly controlled by kinetin.

  3. Oxidative leaching process with cupric ion in hydrochloric acid media for recovery of Pd and Rh from spent catalytic converters

    Energy Technology Data Exchange (ETDEWEB)

    Nogueira, C.A., E-mail: carlos.nogueira@lneg.pt [Laboratório Nacional de Energia e Geologia, I.P., Campus do Lumiar, 1649-038 Lisboa (Portugal); Paiva, A.P., E-mail: appaiva@fc.ul.pt [Centro de Química e Bioquímica, Departamento de Química e Bioquímica, Faculdade de Ciências da Universidade de Lisboa, 1749-016 Lisboa (Portugal); Oliveira, P.C. [Laboratório Nacional de Energia e Geologia, I.P., Campus do Lumiar, 1649-038 Lisboa (Portugal); Costa, M.C., E-mail: mcorada@ualg.pt [Centro de Ciências do Mar, Departamento de Química e Farmácia, Faculdade de Ciências e de Tecnologia, Campus de Gambelas, 8005-139 Faro (Portugal); Costa, A.M. Rosa da, E-mail: amcosta@ualg.pt [Centro de Investigação em Química do Algarve, Departamento de Química e Farmácia, Faculdade de Ciências e de Tecnologia, Campus de Gambelas, 8005-139 Faro (Portugal)

    2014-08-15

    Highlights: • A new leaching process based on Cu{sup 2+}/HCl media for recovering Pd and Rh from spent autocatalytic converters is presented. • Palladium and rhodium were efficiently leached, with attained maximum yields of 95% and 86%, respectively. • Temperature, time, and HCl and Cu{sup 2+} concentrations were found to be significant factors in the leaching of Pd and Rh. - Abstract: The recycling of platinum-group metals from wastes such as autocatalytic converters is getting growing attention due to the scarcity of these precious metals and the market pressure originated by increase of demand in current and emerging applications. Hydrometallurgical treatment of such wastes is an alternative way to the most usual pyrometallurgical processes based on smelter operations. This paper focuses on the development of a leaching process using cupric chloride as oxidising agent, in HCl media, for recovery of palladium and rhodium from a spent catalyst. The chloride media allows the adequate conditions for oxidising and solubilising the metals, as demonstrated by equilibrium calculations based on thermodynamic data. The experimental study of the leaching process revealed that Pd solubilisation is clearly easier than that of Rh. The factors temperature, time, and HCl and Cu{sup 2+} concentrations were significant regarding Pd and Rh leaching, the latter requiring higher factor values to achieve the same results. Leaching yields of 95% Pd and 86% Rh were achieved under optimised conditions (T = 80 °C, t = 4 h, [HCl] = 6 M, [Cu{sup 2+}] = 0.3 M)

  4. Pollen germination of the walnut cultivar ‛Geisenheim 286’ on different culture media

    Directory of Open Access Journals (Sweden)

    Janković Dragan M.

    2014-01-01

    Full Text Available Pollen of the walnut cultivar ‛Geisenheim 286(27.8% when the germination medium contained 0.8% of agar, 15% of sucrose, 600 ppm of ’ was cultured on germination media containing all possible combinations of sucrose (10, 15 and 20%; agar (0.6 and 0.8%; boric acid (0, 300 and 600 ppm and calcium chloride (0, 50 and 100 ppm. A total of 54 different combinations of germination media were tested in an attempt to establish a suitable culture in vitro pollen germinability The interactions of the concentrations of agar and calcium chloride, boric acid and sucrose, calcium chloride and sucrose, as well as those of boric acid, calcium chloride and sucrose were significant. Pollen germination was maximized media for studying of the walnut. Significant differences in pollen germination were observed in response to changing concentrations of sucrose, boric acid and calcium chloride, but germination was not affected by changes in agar concentration. boric acid and 50 ppm of calcium chloride.

  5. Determination of uranium isotopes in environmental samples by anion exchange in sulfuric and hydrochloric acid media.

    Science.gov (United States)

    Popov, L

    2016-09-01

    Method for determination of uranium isotopes in various environmental samples is presented. The major advantages of the method are the low cost of the analysis, high radiochemical yields and good decontamination factors from the matrix elements, natural and man-made radionuclides. The separation and purification of uranium is attained by adsorption with strong base anion exchange resin in sulfuric and hydrochloric acid media. Uranium is electrodeposited on a stainless steel disk and measured by alpha spectrometry. The analytical method has been applied for the determination of concentrations of uranium isotopes in mineral, spring and tap waters from Bulgaria. The analytical quality was checked by analyzing reference materials.

  6. Study of Plant Cordia Dichotoma as Green Corrosion Inhibitor for Mild Steel in Different Acid Media

    Directory of Open Access Journals (Sweden)

    R. Khandelwal

    2011-01-01

    Full Text Available The corrosion inhibition of mild steel using extracts of Cordia dichotoma in different acid media was investigated by mass loss and thermometric methods. The experiments were carried out at 299±0.2 K in presence of different concentrations of dry fruit, leaves and stem extracts of Cordia dichotoma. The results reveal that the alcoholic extracts of Cordia dichotoma is a better corrosion inhibitor than that of toxic chemicals. The fruit extract is more potent than leaves and stem extracts to inhibit the corrosion rate. The study seeks to investigate the possibility of using extracts of Cordia dichotoma as a green corrosion inhibitor for mild steel.

  7. Investigations of corrosion films formed on API-X52 pipeline steel in acid sour media

    Energy Technology Data Exchange (ETDEWEB)

    Hernandez-Espejel, A. [Instituto Politecnico Nacional, Departamento de Ingenieria Metalurgica, IPN-ESIQIE, UPALM Ed. 7, Zacatenco 07738, Mexico, D.F. (Mexico); Dominguez-Crespo, M.A. [Instituto Politecnico Nacional, CICATA-Unidad Altamira-Tamaulipas, km 14.5, Carretera Tampico-Puerto Industrial Altamira, 89600 Altamira, Tamps (Mexico); Cabrera-Sierra, R. [Instituto Politecnico Nacional, Departamento de Ingenieria Quimica Industrial, IPN-ESIQIE, UPALM Ed. 7, Zacatenco 07738, Mexico, D.F. (Mexico); Rodriguez-Meneses, C. [Instituto Politecnico Nacional, Departamento de Ingenieria Metalurgica, IPN-ESIQIE, UPALM Ed. 7, Zacatenco 07738, Mexico, D.F. (Mexico); Arce-Estrada, E.M., E-mail: earce@ipn.m [Instituto Politecnico Nacional, Departamento de Ingenieria Metalurgica, IPN-ESIQIE, UPALM Ed. 7, Zacatenco 07738, Mexico, D.F. (Mexico)

    2010-07-15

    Corrosion films formed by voltammetry using different switching potentials and by immersion on API-X52 pipeline steel in simulated acid sour media (NACE ID182) have been characterized using Scanning Electron Microscopy (SEM), X-ray Diffraction (XRD), Linear Polarization and Electrochemical Impedance Spectroscopy (EIS) techniques. XRD and EDS analysis showed that the films are mainly composed of sulphide compounds (mackinawite, troilite, marcasite and pyrite) as well as iron oxides, as steel damage increases. Across SEM micrographs the corrosion films formed by potentiodynamic and immersion tests are very similar, covering most of the steel. Polarization and EIS results corroborate poor behavior against corrosion.

  8. Agar media that indicate acid production from sorbitol by oral microorganisms.

    OpenAIRE

    Kalfas, S.; Edwardsson, S

    1985-01-01

    Two varieties of agar medium (Trypticase [BBL Microbiology Systems]-serum-sorbitol-bromcresol purple agar [TSSB] and Trypticase-blood-sorbitol-CaCO3 agar [TBSCa]) indicating microbial acid production from sorbitol were tested. The media were devised for use in studies on the prevalence of sorbitol-fermenting human oral microorganisms incubated in an anaerobic or microaerophilic atmosphere containing 5 to 6% CO2. TSSB contains bromcresol purple as the pH indicator and NaHCO3 as the main buffer...

  9. Histologic and biomechanical evaluation of alumina-blasted/acid-etched and resorbable blasting media surfaces.

    Science.gov (United States)

    Bonfante, Estevam A; Marin, Charles; Granato, Rodrigo; Suzuki, Marcelo; Hjerppe, Jenni; Witek, Lukasz; Coelho, Paulo G

    2012-10-01

    This study evaluated the early biomechanical fixation and bone-to-implant contact (BIC) of an alumina-blasted/acid-etched (AB/AE) compared with an experimental resorbable blasting media (RBM) surface in a canine model. Higher texturization was observed for the RBM than for the AB/AE surface, and the presence of calcium and phosphorus was only observed for the RBM surface. Time in vivo and implant surface did not influence torque. For both surfaces, BIC significantly increased from 2 to 4 weeks.

  10. Parameters Affecting Hydrogen Chloride Measurements

    Science.gov (United States)

    1993-06-01

    contain sea salt, which is hygroscopic because of the magnesium chloride present, or ammonium bisulfate , which mostly comes from sulfur pollution and is...boosters release hydrogen chloride as a combustion product, and hydrazines or nitric acid can be spilled from liquid fuel motors. Monitoring the...solubility constant, and the second is the acid ionization constant. From experimental work, the product of the two constants is well established (Reference

  11. Study of the interaction metallic cation - ligand in concentrated phosphorus acid media; Etude de l'interaction cation metallique - ligand en milieu acide phosphorique concentre

    Energy Technology Data Exchange (ETDEWEB)

    Sefiani, N.; Azzi, M.; Hlaibi, M. [Faculte des Sciences Ain Chock, Laboratoire d' Electrochimie et Chimie de l' Environnement (LECE), Casablanca (Morocco); Kossair, A. [Centre de Recherche des Phosphates Mineraux (CERPHOS), Casablanca (Morocco)

    2005-07-01

    The phosphoric acid is more and more used with a high purity. The recovery of recycling element (uranium, vanadium, rare earth...) and the elimination of toxic element (cadmium, molybdenum, lead...) contained in the phosphoric acid are generally realized by extraction or precipitation. It is then very important to understand these impurities behavior in the phosphoric media in order to control their elimination. In this work, the authors considered the presence of some metallic cations (V, Al, fe, U) and fluorides ions as impurity in concentrated phosphoric acid media. (A.L.B.)

  12. Strontium chloride-catalyzed one-pot synthesis of 2, 3-dihydroquinazolin-4(1H)-ones in protic media

    Institute of Scientific and Technical Information of China (English)

    Min Wang; Ting Ting Zhang; Yan Liang; Jing Jing Gao

    2011-01-01

    A wide range of mono- and disubstituted 2, 3-dihydroquinazolin-4(1H)-ones were obtained in high yields by condensation of isatoic anhydride, aldehydes with ammonium salts or primary amines in the presence of strontium chloride in aqueous ethanol under reflux.

  13. Simultaneous analysis of apolar phytohormones and 1-aminocyclopropan-1-carboxylic acid by high performance liquid chromatography/electrospray negative ion tandem mass spectrometry via 9-fluorenylmethoxycarbonyl chloride derivatization.

    Science.gov (United States)

    Ziegler, Jörg; Qwegwer, Jakob; Schubert, Melvin; Erickson, Jessica L; Schattat, Martin; Bürstenbinder, Katharina; Grubb, C Douglas; Abel, Steffen

    2014-10-03

    A strategy to detect and quantify the polar ethylene precursor 1-aminocyclopropan-1-carboxylic acid (ACC) along with the more apolar phytohormones abscisic acid (ABA), indole-3-acetic acid (IAA), jasmonic acid (JA), jasmonic acid-isoleucine conjugate (JA-Ile), 12-oxo-phytodienoic acid (OPDA), trans-zeatin, and trans-zeatin 9-riboside using a single extraction is presented. Solid phase resins commonly employed for extraction of phytohormones do not allow the recovery of ACC. We circumvent this problem by attaching an apolar group to ACC via derivatization with the amino group specific reagent 9-fluorenylmethoxycarbonyl chloride (Fmoc-Cl). Derivatization in the methanolic crude extract does not modify other phytohormones. The derivatized ACC could be purified and detected together with the more apolar phytohormones using common solid phase extraction resins and reverse phase HPLC/electrospray negative ion tandem mass spectrometry. The limit of detection was in the low nanomolar range for all phytohormones, a sensitivity sufficient to accurately determine the phytohormone levels from less than 50mg (fresh weight) of Arabidopsis thaliana and Nicotiana benthamiana tissues. Comparison with previously published phytohormone levels and the reported changes in phytohormone levels after stress treatments confirmed the accuracy of the method.

  14. Presence of viral nucleic acids in the middle ear: acute otitis media pathogen or bystander?

    Science.gov (United States)

    Chonmaitree, Tasnee; Ruohola, Aino; Hendley, J Owen

    2012-04-01

    Viruses play an important role in acute otitis media (AOM) pathogenesis, and live viruses may cause AOM in the absence of pathogenic bacteria. Detection of AOM pathogens generally relies on bacterial culture of middle ear fluid. When viral culture is used and live viruses are detected in the middle ear fluid of children with AOM, the viruses are generally accepted as AOM pathogens. Because viral culture is not sensitive and does not detect the comprehensive spectrum of respiratory viruses, polymerase chain reaction assays are commonly used to detect viral nucleic acids in the middle ear fluid. Although polymerase chain reaction assays have greatly increased the viral detection rate, new questions arise on the significance of viral nucleic acids detected in the middle ear because nucleic acids of multiple viruses are detected simultaneously, and nucleic acids of specific viruses are detected repeatedly and in a high proportion of asymptomatic children. This article first reviews the role of live viruses in AOM and presents the point-counterpoint arguments on whether viral nucleic acids in the middle ear represent an AOM pathogen or a bystander status. Although there is evidence to support both directions, helpful information for interpretation of the data and future research direction is outlined.

  15. Ozonation of azo dyes (Orange II and Acid Red 27) in saline media

    Energy Technology Data Exchange (ETDEWEB)

    Silva, Alessandra C. [Chemical Engineering Program, COPPE, Federal University of Rio de Janeiro, Av. Horacio Macedo, 2030, P.O. Box, 68502, CEP 21941-972, Rio de Janeiro, RJ (Brazil); Pic, Jean Stephane [Institut National des Sciences Appliquees, INSA-GPE-LIPE, Toulouse (France); Sant' Anna, Geraldo L., E-mail: lippel@peq.coppe.ufrj.br [Chemical Engineering Program, COPPE, Federal University of Rio de Janeiro, Av. Horacio Macedo, 2030, P.O. Box, 68502, CEP 21941-972, Rio de Janeiro, RJ (Brazil); Dezotti, Marcia [Chemical Engineering Program, COPPE, Federal University of Rio de Janeiro, Av. Horacio Macedo, 2030, P.O. Box, 68502, CEP 21941-972, Rio de Janeiro, RJ (Brazil)

    2009-09-30

    Ozonation of two azo dyes was investigated in a monitored bench scale bubble column reactor (8.5-L), varying liquid media salt content (0, 1, 40 and 100 g L{sup -1}, NaCl). In experiments with Orange II pH was varied (5, 7.5 and 9) but ozonation of Acid Red 27 was performed at pH 7.5. Ozone self-decomposition rate-constant increased with salt concentration. Color removal was very effective and fast achieved under all experimental conditions. For the two azo dyes tested, more than 98% of color intensity was removed in 30-min ozonation assays. However, only partial mineralization of azo dyes (45%-Orange II; 20%-Acid Red 27) was attained in such experiments. The degree of mineralization (TOC removal) was negatively affected by salt concentration. Biodegradation assays conducted by respirometry revealed the inhibitory effect of dye degradation products formed during ozonation.

  16. Adsorption and corrosion inhibition of mild steel in acidic media by expired pharmaceutical drug

    Directory of Open Access Journals (Sweden)

    P. Geethamani

    2015-12-01

    Full Text Available The inhibitive action of an examined expired Ambroxol drug on the corrosion of mild steel in 1 M HCl and 1 M H2SO4 acid medium has been studied by weight loss and electrochemical techniques. The weight loss techniques result was discussed. The inhibition efficiency increases with increasing the concentration of the inhibitor. Electrochemical studies data support that examined expired drug is an efficient inhibitor for mild steel corrosion. The adsorption of the examined drug obeys Langmuir’s adsorption isotherm. Polarization studies indicate that this inhibitor acts as a mixed type inhibition. The various thermodynamic parameters were calculated and discussed. The protective film formed on the surface was confirmed by SEM. The data collected from the studied techniques are in good agreement to confirm the ability of using expired Ambroxol drug as corrosion inhibitor for mild steel in both acid media.

  17. Choline chloride (ChCl) and monosodium glutamate (MSG)-based green solvents from optimized cactus malic acid for biomass delignification.

    Science.gov (United States)

    Yiin, Chung Loong; Quitain, Armando T; Yusup, Suzana; Uemura, Yoshimitsu; Sasaki, Mitsuru; Kida, Tetsuya

    2017-08-10

    This work aimed to develop an efficient microwave-hydrothermal (MH) extraction of malic acid from abundant natural cactus as hydrogen bond donor (HBD) whereby the concentration was optimized using response surface methodology. The ideal process conditions were found to be at a solvent-to-feed ratio of 0.008, 120°C and 20min with 1.0g of oxidant, H2O2. Next generation environment-friendly solvents, low transition temperature mixtures (LTTMs) were synthesized from cactus malic acid with choline chloride (ChCl) and monosodium glutamate (MSG) as hydrogen bond acceptors (HBAs). The hydrogen-bonding interactions between the starting materials were determined. The efficiency of the LTTMs in removing lignin from oil palm biomass residues, empty fruit bunch (EFB) was also evaluated. The removal of amorphous hemicellulose and lignin after the pretreatment process resulted in an enhanced digestibility and thermal degradability of biomass. Copyright © 2017 Elsevier Ltd. All rights reserved.

  18. Protective role of acidic pH-activated chloride channel in severe acidosis-induced contraction from the aorta of spontaneously hypertensive rats.

    Directory of Open Access Journals (Sweden)

    Zhiyong Ma

    Full Text Available Severe acidic pH-activated chloride channel (ICl,acid has been found in various mammalian cells. In the present study, we investigate whether this channel participates in reactions of the thoracic aorta to severe acidosis and whether it plays a role in hypertension. We measured isometric contraction in thoracic aorta rings from spontaneously hypertensive rats (SHRs and normotensive Wistar rats. Severe acidosis induced contractions of both endothelium-intact and -denuded thoracic aorta rings. In Wistar rats, contractions did not differ at pH 6.4, 5.4 and 4.4. However, in SHRs, contractions were higher at pH 5.4 or 4.4 than pH 6.4, with no difference between contractions at pH 5.4 and 4.4. Nifedipine, ICl,acid blockers 5-nitro-2-(3-phenylpropylamino benzoic acid (NPPB and 4,4'-diisothiocyanatostilbene-2, 2'-disulfonic acid (DIDS inhibited severe acidosis-induced contraction of aortas at different pH levels. When blocking ICl,acid, the remnant contraction was greater at pH 4.4 than pH 5.4 and 6.4 for both SHRs and Wistar rats. With nifedipine, the remnant contraction was greatly reduced at pH 4.4 as compared with at pH 6.4 and 5.4. With NPPB or DIDS, the ratio of remnant contractions at pH 4.4 and 5.4 (R4.4/5.4 was lower for SHRs than Wistar rats (all 1. Furthermore, patch clamp recordings of ICl,acid and intracellular Ca(2+ measurements in smooth muscle cells confirmed these findings. ICl,acid may protect arteries against excess vasoconstriction under extremely acidic extracellular conditions. This protective effect may be decreased in hypertension.

  19. Protective Role of Acidic pH-Activated Chloride Channel in Severe Acidosis-Induced Contraction from the Aorta of Spontaneously Hypertensive Rats

    Science.gov (United States)

    Ma, Zhiyong; Qi, Jia; Fu, Zhijie; Ling, Mingying; Li, Li; Zhang, Yun

    2013-01-01

    Severe acidic pH-activated chloride channel (ICl,acid) has been found in various mammalian cells. In the present study, we investigate whether this channel participates in reactions of the thoracic aorta to severe acidosis and whether it plays a role in hypertension. We measured isometric contraction in thoracic aorta rings from spontaneously hypertensive rats (SHRs) and normotensive Wistar rats. Severe acidosis induced contractions of both endothelium-intact and -denuded thoracic aorta rings. In Wistar rats, contractions did not differ at pH 6.4, 5.4 and 4.4. However, in SHRs, contractions were higher at pH 5.4 or 4.4 than pH 6.4, with no difference between contractions at pH 5.4 and 4.4. Nifedipine, ICl,acid blockers 5-nitro-2-(3-phenylpropylamino) benzoic acid (NPPB) and 4,4′-diisothiocyanatostilbene-2, 2′-disulfonic acid (DIDS) inhibited severe acidosis-induced contraction of aortas at different pH levels. When blocking ICl,acid, the remnant contraction was greater at pH 4.4 than pH 5.4 and 6.4 for both SHRs and Wistar rats. With nifedipine, the remnant contraction was greatly reduced at pH 4.4 as compared with at pH 6.4 and 5.4. With NPPB or DIDS, the ratio of remnant contractions at pH 4.4 and 5.4 (R4.4/5.4) was lower for SHRs than Wistar rats (all 1). Furthermore, patch clamp recordings of ICl,acid and intracellular Ca2+ measurements in smooth muscle cells confirmed these findings. ICl,acid may protect arteries against excess vasoconstriction under extremely acidic extracellular conditions. This protective effect may be decreased in hypertension. PMID:23580361

  20. Dissolution properties of co-amorphous drug-amino acid formulations in buffer and biorelevant media.

    Science.gov (United States)

    Heikkinen, A T; DeClerck, L; Löbmann, K; Grohganz, H; Rades, T; Laitinen, R

    2015-07-01

    Co-amorphous formulations, particularly binary drug-amino acid mixtures, have been shown to provide enhanced dissolution for poorly-soluble drugs and improved physical stability of the amorphous state. However, to date the dissolution properties (mainly intrinsic dissolution rate) of the co-amorphous formulations have been tested only in buffers and their supersaturation ability remain unexplored. Consequently, dissolution studies in simulated intestinal fluids need to be conducted in order to better evaluate the potential of these systems in increasing the oral bioavailability of biopharmaceutics classification system class II drugs. In this study, solubility and dissolution properties of the co-amorphous simvastatin-lysine, gibenclamide-serine, glibenclamide-threonine and glibenclamide-serine-threonine were studied in phosphate buffer pH 7.2 and biorelevant media (fasted and fed state simulated intestinal fluids (FaSSIF and FeSSIF, respectively)). The co-amorphous formulations were found to provide a long-lasting supersaturation and improve the dissolution of the drugs compared to the crystalline and amorphous drugs alone in buffer. Similar improvement, but in lesser extent, was observed in biorelevant media suggesting that a dissolution advantage observed in aqueous buffers may overestimate the advantage in vivo. However, the results show that, in addition to stability advantage shown earlier, co-amorphous drug-amino acid formulations provide dissolution advantage over crystalline drugs in both aqueous and biorelevant conditions.

  1. Determination of dissociation parameters of weak acids in different media according to the isohydric method.

    Science.gov (United States)

    Michałowski, Tadeusz; Pilarski, Bogusław; Asuero, Agustin G; Dobkowska, Agnieszka; Wybraniec, Sławomir

    2011-10-30

    The isohydricity (pH constancy) principle is referred to the pair of solutions: weak acid (HL, C(0)mol/L) and strong acid (HB, C mol/L) when mixed e.g., according to titrimetric mode. Such a case takes place if the relation C(0)=C+C(2) × 10(pK(1)) is valid, where pK(1)=-log K(1), K(1) - dissociation constant for a weak monoprotic acid HL. This principle, outlined and formulated in earlier paper (Michałowski et al., Talanta 82 (2010) 1965), is the basis for a sensitive method of pK(1) determination, confirmed for a series of weak acids in presence of basal electrolytes or in water+organic solvent (dimethyl sulphoxide, methanol, isopropanol) media. The results of titrations were elaborated according to principles of regression analysis, with use of least squares method. A new criterion for precision of the results obtained according to this method is formulated. The pK(1) values obtained are comparable with ones found in literature.

  2. Study of the autocatalytic chlorate–triiodide reaction in acidic and neutral media

    Directory of Open Access Journals (Sweden)

    Ahmad M. Mohammad

    2010-07-01

    Full Text Available The oxidation reaction of triiodide, I3−, by chlorate is investigated in a slightly acidic and neutral media. The reaction was verified and monitored both potentiometrically and spectrophotometrically. Generally, a slow linear decay preceded by an induction period was observed for the triiodide concentration following the addition of chlorate. The induction period is likely to be related to the time required for the generation of suitable concentrations of plausible intermediates (HIO and HIO2, which are assumed to auto-catalyse the reaction. We examined the effect of acidity and concentrations of both chlorate and triiodide on the induction time for this reaction. The acidity of the medium influenced the induction period, while the oxidation of iodide by chlorate competed with that of iodine as the medium acidity increased, making the reaction more complicated. Therefore, a suitable pH is highly recommended for studying the chlorate–triiodide reaction. A plausible mechanism involving the HIO, HIO2, and I2O species is proposed.

  3. Cellulose acetate layer effect toward aluminium corrosion rate in hydrochloric acid media

    Science.gov (United States)

    Andarany, K. S.; Sagir, A.; Ahmad, A.; Deni, S. K.; Gunawan, W.

    2017-09-01

    Corrosion occurs due to the oxidation and reduction reactions between the material and its environment. The oxidation reaction defined as reactions that produce electrons and reduction is between two elements that bind the electrons. Corrosion cannot be inevitable in life both within the industry and household. Corrosion cannot eliminate but can be control. According to the voltaic table, Aluminum is a metal that easily corroded. This study attempts to characterize the type of corrosion by using a strong acid media (HCl). Experiment using a strong acid (HCl), at a low concentration that occurs is pitting corrosion, whereas at high concentrations that occurs is corrosion erosion. One of prevention method is by using a coating method. An efforts are made to slow the rate of corrosion is by coating the metal with “cellulose acetate” (CA). cellulose acetate consisted of cellulose powder dissolved in 99% acetic acid, and then applied to the aluminum metal. Soaking experiments using hydrochloric acid, cellulose acetate is able to slow down the corrosion rate of 47 479%.

  4. Influence of sodium chloride and weak organic acids (flux residues) on electrochemical migration of tin on surface mount chip components

    DEFF Research Database (Denmark)

    Verdingovas, Vadimas; Jellesen, Morten Stendahl; Ambat, Rajan

    2013-01-01

    The electrolytic properties of sodium chloride and no-clean solder flux residue, and their effects on electrochemical migration and dendrite growth on surface mount chip capacitors were investigated. The leakage current dependency on concentration of contaminants was measured by a solution...... showed a difference which is caused by polarization effects, and demonstrated existing issues when indexing contamination levels on printed circuit board assemblies using a standardised solvent extract method. The experimental results showed that dendrite growth was dependent on the type and amount...

  5. Bile components and amino acids affect survival of the newly excysted juvenile Clonorchis sinensis in maintaining media.

    Science.gov (United States)

    Li, Shunyu; Kim, Tae Im; Yoo, Won Gi; Cho, Pyo Yun; Kim, Tong-Soo; Hong, Sung-Jong

    2008-10-01

    Clonorchis sinensis thrives on bile juice. The effects of bile and bile acids on newly excysted juvenile C. sinensis (CsNEJ) were studied in terms of survival. Survival of CsNEJs maintained in 1x Locke's solution, Dulbecco's modified Eagle's medium, NCTC 109, Eagle's, RPMI 1640, and 0.1% glucose was high, but dropped rapidly in 2x Locke's, 0.85% NaCl, and phosphate-buffered saline. Most amino acids in the media favored CsNEJ survival; however, aspartic and glutamic acids and adenine reduced survival. Survival was also significantly lower in media containing more than 0.1% bile. CsNEJs preconditioned in low bile media survived longer in higher bile media. All bile acids and conjugated bile salts were found to favor CsNEJ survival, except for lithocholic acid (LCA) which was toxic. NCTC 109 medium was found to be optimal for the in vitro maintenance of CsNEJs and 1x Locke's solution to be suitable for analyzing the biological effects of bioactive compounds and molecules. Based on these results, we propose that bile acids enhance activity of CsNEJs, but LCA deteriorate CsNEJs.

  6. Oxidative leaching process with cupric ion in hydrochloric acid media for recovery of Pd and Rh from spent catalytic converters.

    Science.gov (United States)

    Nogueira, C A; Paiva, A P; Oliveira, P C; Costa, M C; da Costa, A M Rosa

    2014-08-15

    The recycling of platinum-group metals from wastes such as autocatalytic converters is getting growing attention due to the scarcity of these precious metals and the market pressure originated by increase of demand in current and emerging applications. Hydrometallurgical treatment of such wastes is an alternative way to the most usual pyrometallurgical processes based on smelter operations. This paper focuses on the development of a leaching process using cupric chloride as oxidising agent, in HCl media, for recovery of palladium and rhodium from a spent catalyst. The chloride media allows the adequate conditions for oxidising and solubilising the metals, as demonstrated by equilibrium calculations based on thermodynamic data. The experimental study of the leaching process revealed that Pd solubilisation is clearly easier than that of Rh. The factors temperature, time, and HCl and Cu(2+) concentrations were significant regarding Pd and Rh leaching, the latter requiring higher factor values to achieve the same results. Leaching yields of 95% Pd and 86% Rh were achieved under optimised conditions (T = 80 °C, t = 4h, [HCl] = 6M, [Cu(2+)] = 0.3M).

  7. Synthesis and Performances of Acrylamide-2-Acrylamido-2-Methylpropanesulfonic Acid-Methacrylic Acid-Diallyl Dimethyl Ammonium Chloride Quadripolymer%AM/AMPS/MAA/DADMAC四元共聚物的合成与性能

    Institute of Scientific and Technical Information of China (English)

    王中华

    2001-01-01

    Acrylamide-2-acrylamido-2-methylpropanesulfonic acid-methacrylic acid-diallyl dimethyl ammonium chloride quadripolymer as drilling-fluid additive was synthesized by redox initation. The mud performances of the quadripolymer was evaluated in the laboratory. The results showed that acrylamide-2-acrylamido-2-methylpropanesulfonic acid-methacrylic acid-diallyl dimethyl ammonium chloride quadripolymer has very good heat resistance,depressing filter loss, salt tolerance, and protection against collapse.%采用氧化-还原引发体系合成丙烯酰胺/2-丙烯酰胺基-2-甲基丙磺酸/甲基丙烯酸/二烯丙基二甲基氯化铵四元共聚物作为钻井液处理剂。初步评价了此四元共聚物的泥浆性能,结果表明,AM/AMPS/MAA/DADMAC四元共聚物具有较好的降滤失和耐温性能,较强的抗盐能力,及较好的防塌效果。

  8. Effects of Different Oral Doses of Sodium Chloride on the Basal Acid-Base and Mineral Status of Exercising Horses Fed Low Amounts of Hay

    Science.gov (United States)

    Zeyner, Annette; Romanowski, Kristin; Vernunft, Andreas; Harris, Patricia; Müller, Ann-Marie; Wolf, Carola; Kienzle, Ellen

    2017-01-01

    The provision of NaCl, according to current recommendations, to horses in moderate work has been shown to induce immediate postprandial acidosis. The present study aimed to clarify whether this NaCl induced acidosis i) persists beyond the immediate postprandial period, and ii) is still present after a 2 week adaptation period. Six adult warmblood mares in moderate work received daily 1.00 kg hay per 100 kg body weight (bwt) only together with 0.64 kg unprocessed cereal grains/100 kg bwt.d as fed basis. Using a 3x3 Latin Square, either 0 (NaCl-0), 50 (NaCl-50) or 100 (NaCl-100) g NaCl/d were fed together with the concentrates in two equal doses for 3 weeks. During the final week, a mineral digestibility trial was undertaken. The middle sodium and chloride intake (NaCl-50) at least met the most common recommendations for moderate work. Morning (7:00 AM) urine and venous blood samples were collected on days 0, 1–4, 8, and 15, and analysed for pH, acid-base status, creatinine and electrolyte concentrations. Fractional electrolyte clearances (FC) were determined. Mean apparent sodium digestibility ranged between 60–62% whereas chloride digestibility was consistently above 94%. Supplementing 100 g but not 50 g of NaCl resulted in significant reduction of blood pH and base excess as well as urinary pH and urine acid excretion. Both 50 g and 100 g NaCl supplementation caused a significant reduction in base and net acid-base excretion, urine density and potassium concentration, but increased urine sodium concentration and the FC of sodium and chloride (P < 0.05). This suggests that a high proportion of the recommended salt doses is excreted renally. The above effects of NaCl supplementation persisted over the 2 week measurement period. Results suggest that feeding 100 g NaCl to moderately exercising horses results in mild metabolic acidosis, whereas feeding 50 g according to current recommendations resulted in compensated acidosis. PMID:28045916

  9. Expression of lysophosphatidic acid receptor 1 and relation with cell proliferation, apoptosis, and angiogenesis on preneoplastic changes induced by cadmium chloride in the rat ventral prostate.

    Directory of Open Access Journals (Sweden)

    Riánsares Arriazu

    Full Text Available BACKGROUND: Lysophosphatidic acid (LPA is a phospholipid growth factor involved in cell proliferation, differentiation, migration, inflammation, angiogenesis, wound healing, cancer invasion, and survival. This study was directed to evaluate the immunoexpression of LPA-1, cell proliferation, apoptosis, and angiogenesis markers in preneoplastic lesions induced with cadmium chloride in rat prostate. METHODS: The following parameters were calculated in ventral prostate of normal rats and rats that received Cd in drinking water during 24 months: percentages of cells immunoreactive to LPA-1 (LILPA1, PCNA (LIPCNA, MCM7 (LIMCM7, ubiquitin (LIUBI, apoptotic cells (LIAPO, and p53 (LIp53; volume fraction of Bcl-2 (VFBcl-2; and length of microvessels per unit of volume (LVMV/mm3. Data were analyzed using Student's t-test and Pearson correlation test. RESULTS: The LILPA1 in dysplastic lesions and normal epithelium of Cd-treated rats was significantly higher than those in the control group. Markers of proliferation were significantly increased in dysplastic lesions, whereas some apoptotic markers were significantly decreased. No significant differences between groups were found in VFBcl-2. Dysplastic lesions showed a significant increase of LIp53. The length of microvessels per unit of volume was elevated in dysplastic acini. Statistically significant correlations were found only between LILPA1 and LIUBI. CONCLUSIONS: Our results suggest that LPA-1 might be implicated in dysplastic lesions induced by cadmium chloride development. More studies are needed to confirm its potential contribution to the disease.

  10. Chronic suppurative otitis media due to nontuberculous mycobacteria: A case of successful treatment with topical boric acid.

    Science.gov (United States)

    Lefebvre, Marie-Astrid; Quach, Caroline; Daniel, Sam J

    2015-07-01

    Nontuberculous mycobacteria (NTM) are an increasingly recognized cause of chronic suppurative otitis media in children with tympanostomy tubes. Treatment of this condition is difficult and typically requires a combination of systemic antibiotics and surgical debridement. We present the first case of a 2-year-old male with chronic suppurative otitis media due to NTM who failed systemic antibiotic therapy and was successfully managed with topical boric acid powder. This report highlights the challenges involved in treating this infection, and introduces boric acid as a potentially valuable component of therapy. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.

  11. Microsystems for anion exchange separation of radionuclides in nitric acid media

    Energy Technology Data Exchange (ETDEWEB)

    Losno, M.; Brennetot, R.; Mariet, C. [DEN/Service d' Etudes Analytiques et de Reactivite des Surfaces - SEARS, CEA, Centre de Saclay, Universite Paris-Saclay, F-91191, Gif sur Yvette (France); Ferrante, I.; Descroix, S. [MMBM Group, Institut Curie Research Center, CNRS UMR 168, Paris (France)

    2016-07-01

    An efficient and reproducible photo-polymerized poly(ethylene glycol methacrylate methacrylate-co- allyl methacrylate) monolith was synthesized and a photo-grafting process based on the ene-thiol click-chemistry has been performed to give anion exchange properties to the monolith. Since their introduction in the early 1990's polymethacrylate monoliths have emerged as a powerful alternative for microscale separations or sample treatment. Their relatively simple implementation in columns with small internal diameters makes them particularly attractive for the new chromatographic challenges of complex matrices analysis and on-chip separations. Despite their relatively poor ion-exchange capacity due to their highly porous structure, their use as anion exchangers is of large interest for nuclear analysis as numerous separations are based on this process. This paper presents a systematic study of the synthesis of the polymeric porous monolith and the versatile and robust functionalization method developed for the specific strong acidic media used in radiochemical procedures. The robustness of the stationary phase was tested in concentrated nitric acid. It appears that the C-S bond formed via thiol-ene chemistry is strong enough to be used to graft function of interest for separation in strong nitric acid medium. The photo-grafted anion exchanger, a quaternary ammonium, presents sufficient resistance to be used for radionuclide separation in [HNO{sub 3}]=5 mol.L{sup -1}so the next step is its integration in the cyclo olefin copolymer (COC) micro-system.

  12. Molecular dynamics study of solvation effects on acid dissociation in aprotic media

    CERN Document Server

    Laria, D; Estrin, D A; Ciccotti, G; Laria, Daniel; Kapral, Raymond; Estrin, Dario; Ciccotti, Giovanni

    1996-01-01

    Acid ionization in aprotic media is studied using Molecular Dynamics techniques. In particular, models for HCl ionization in acetonitrile and dimethylsulfoxide are investigated. The proton is treated quantum mechanically using Feynman path integral methods and the remaining molecules are treated classically. Quantum effects are shown to be essential for the proper treatment of the ionization. The potential of mean force is computed as a function of the ion pair separation and the local solvent structure is examined. The computed dissociation constants in both solvents differ by several orders of magnitude which are in reasonable agreement with experimental results. Solvent separated ion pairs are found to exist in dimethylsulfoxide but not in acetonitrile. Dissociation mechanisms in small clusters are also investigated. Solvent separated ion pairs persist even in aggregates composed of rather few molecules, for instance, as few as thirty molecules. For smaller clusters or for large ion pair separations cluste...

  13. Dissolution properties of co-amorphous drug-amino acid formulations in buffer and biorelevant media

    DEFF Research Database (Denmark)

    Heikkinen, A. T.; DeClerck, L.; Löbmann, Korbinian

    2015-01-01

    classification system class II drugs. In this study, solubility and dissolution properties of the co-amorphous simvastatin-lysine, gibenclamideserine, glibenclamide-threonine and glibenclamide-serine-threonine were studied in phosphate buffer pH 7.2 and biorelevant media (fasted and fed state simulated......Co-amorphous formulations, particularly binary drug-amino acid mixtures, have been shown to provide enhanced dissolution for poorly-soluble drugs and improved physical stability of the amorphous state. However, to date the dissolution properties (mainly intrinsic dissolution rate) of the co......-amorphous formulations have been tested only in buffers and their supersaturation ability remain unexplored. Consequently, dissolution studies in simulated intestinal fluids need to be conducted in order to better evaluate the potential of these systems in increasing the oral bioavailability of biopharmaceutics...

  14. Optical reflectance, optical refractive index and optical conductivity measurements of nonlinear optics for L-aspartic acid nickel chloride single crystal

    Science.gov (United States)

    Anbazhagan, G.; Joseph, P. S.; Shankar, G.

    2013-03-01

    Single crystals of L-aspartic acid nickel chloride (LANC) were grown by the slow evaporation technique at room temperature. The grown crystals were subjected to Powder X-ray diffraction studies to confirm the crystal structure. The modes of vibration of different molecular groups present in LANC have been identified by FTIR spectral analysis. Optical transferency of the grown crystal was investigated by UV-Vis-NIR spectrum. The lower optical cut off wavelength for this crystal is observed at 240 nm and energy band gap 5.179 eV. The optical reflectance and optical refractive index studies have been carried out in this crystal. Finally, the optical conductivity and electrical conductivity studies have been carried out on LANC single crystal.

  15. Nickel-catalyzed cross-coupling of functionalized difluoromethyl bromides and chlorides with aryl boronic acids: a general method for difluoroalkylated arenes.

    Science.gov (United States)

    Xiao, Yu-Lan; Guo, Wen-Hao; He, Guo-Zhen; Pan, Qiang; Zhang, Xingang

    2014-09-08

    Transition-metal-catalyzed difluoroalkylation of aromatics remains challenging despite the importance of difluoroalkylated arenes in medicinal chemistry. Herein, the first successful example of nickel-catalyzed difluoroalkylation of aryl boronic acids is described. The reaction allows access to a variety of functionalized difluoromethyl bromides and chlorides, and paves the way to highly cost-efficient synthesis of a wide range of difluoroalkylated arenes. The notable features of this protocol are its high generality, excellent functional-group compatibility, low-cost nickel-catalyst, and practicality for gram-scale production, thus providing a facile method for applications in drug discovery and development. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  16. Separation of DR synthesized Ti-Mg Alloy by dissolution of waste by-products in acid media

    CSIR Research Space (South Africa)

    Mushove, T

    2010-06-01

    Full Text Available Of DR Synthesized Ti-Mg Alloy By Dissolution Of Waste By-Products In Acid Media. The dissolution experiments were done in a Julabo SW23 waterbath shaker, with 300 ml flasks. Acid solution of predetermined molarity was charged into a flask and heated... - 200rpm Inorganic Acid Leach time - 40mins temperature - 90oC Organic Acid leach time - 2.5hrs temperature - 60oC Filtration leach residues XRD Dissolution efficiencies Separate TiO2, Ti-20Mg alloy and MgO powders were leached in the same...

  17. Surface characterization of poly(vinyl chloride) urinary catheters functionalized with acrylic acid and poly(ethylene glycol) methacrylate using gamma-radiation

    Energy Technology Data Exchange (ETDEWEB)

    Islas, Luisa [Departamento de Química de Radiaciones y Radioquímica, Instituto de Ciencias Nucleares, Universidad Nacional Autónoma de México, Ciudad Universitaria, Mexico D.F. 04510 (Mexico); Ruiz, Juan-Carlos [División de Ciencias Básicas e Ingeniería, Depto. de Ingeniería de Procesos e Hidráulica, Universidad Autónoma Metropolitana-Iztapalapa, Av. San Rafael Atlixco No. 186, 09340 México D.F. (Mexico); Muñoz-Muñoz, Franklin [Facultad de Ingeniería, Arquitectura y Diseño, Universidad Autónoma de Baja California, Carretera Transpeninsular Ensenada-Tijuana 3917, Ensenada, B.C. C.P 22860 (Mexico); Isoshima, Takashi [Nano Medical Engineering Laboratory, RIKEN, 2-1Hirosawa, Wako, Saitama 351-0198 (Japan); Burillo, Guillermina, E-mail: burillo@nucleares.unam.mx [Departamento de Química de Radiaciones y Radioquímica, Instituto de Ciencias Nucleares, Universidad Nacional Autónoma de México, Ciudad Universitaria, Mexico D.F. 04510 (Mexico)

    2016-10-30

    Highlights: • Polymer grafting using gamma-radiation allowed for acrylic acid and poly(ethylene glycol) methacrylate to graft on the inner and outer surface of poly(vinyl chloride) urinary catheters. • HR-XPS revealed the different compositional percentages of the compounds present on the surface of the catheter. • Catheters that were grafted with PEGMA had the roughest surface as observed using scanning electron microscopy (SEM) and confocal laser microscopy (CLM). - Abstract: Poly(vinyl chloride) (PVC) urinary catheters were modified with either a single or binary graft of acrylic acid (AAc) and/or poly(ethylene glycol) methacrylate (PEGMA) using gamma-radiation from {sup 60}Co to obtain PVC-g-AAc, PVC-g-PEGMA, [PVC-g-AAc]-g-PEGMA, and [PVC-g-PEGMA]-g-AAc copolymers. The outer and inner surfaces of the modified catheters were characterized using scanning electron microscopy (SEM), confocal laser microscopy (CLM) and X-ray photoelectron spectroscopy (XPS). The XPS analyses, by examining the correlation between the variation of the C{sub 1s} and O{sub 1s} content at the catheter’s surface, revealed that the catheter’s surfaces were successfully grafted with the chosen compounds, with those that were binary grafted showing a slightly more covered surface as was evidenced by the disappearance of PVC’s Cl peak. The SEM and CLM analyses revealed that catheters that had been grafted with PEGMA had a rougher outer surface as compared to those that had only been grafted with AAc. In addition, these imaging techniques showed that the inner surface of the singly grafted catheters, whether they had been grafted with AAc or PEGMA, retained some smoothness at the analyzed grafting percentages, while the binary grafted catheters showed many protuberances and greater roughness on both outer and inner surfaces.

  18. Simultaneous determination of amino acids and carbohydrates in culture media of Clostridium thermocellum by valve-switching ion chromatography.

    Science.gov (United States)

    Fa, Yun; Yang, Haiyan; Ji, Chengshuai; Cui, He; Zhu, Xinshu; Du, Juan; Gao, Jun

    2013-10-10

    An improved method for the simultaneous determination of 20 amino acids and 7 carbohydrates using one-valve switching after injection, ion chromatography, and integrated pulsed amperometric detection is proposed. The resolution of the amino acids and carbohydrates in the cation trap column was investigated. In addition, parameters including flow liquid type, flow rate, concentration, and valve-switch timing were optimized. The method is time-saving, effective, and accurate for the simultaneous separation of amino acids and carbohydrates, with a mean correlation coefficient of >0.99 and repeatability of 0.5-4.6% for eight replicates. The method was successfully applied in the analysis of amino acids and carbohydrates in aseptic media and in extracellular culture media of three phenotypes of Clostridium thermocellum.

  19. CITRIC ACID PRODUCTION BY WILD AND UV - TREATED STRAINS OF ASPERGILLUS NIGER ON TWO DIFFERENT MINERAL SALT MEDIA

    OpenAIRE

    Valentine Enyinna Anyanwu; Phillip O. Okerentugba

    2013-01-01

    Microbial production of citric acid by a novel Aspergillus niger EE-12 and its UV – treated strain (UV-1) were carried out in shake flask cultures using mineral salt media containing sucrose or fructose as the carbon and energy sources. The highest citric acid concentration (36.1g/l) was obtained with the UV – treated strain UV-1 after 144 hours in medium containing sucrose and this was significantly higher (p

  20. 铜粉处理酸性镀铜溶液中氯离子的机理%Mechanism of Treating Chloride Ion in Acidic Copper Plating Bath with Copper Powder

    Institute of Scientific and Technical Information of China (English)

    郭崇武

    2011-01-01

    阐明了用铜粉处理酸性镀铜溶液中氯离子的机理,理论分析和实验表明,在酸性镀铜溶液中,Cu2+离子与铜粉反应生成Cu+离子,同时氯离子与Cu+离子反应生成氯化亚铜沉淀.向镀液中加铜粉1g/L,氯离子的起始质量浓度为174mg/L时,氯离子的去除率为58.9%,而向镀液中加锌粉1g/L,氯离子的去除率为47.0%,用铜粉处理氯离子的效率较高.%The mechanism of treating chloride ion in acidic copper plating bath by using copper powder was illustrated. Theoretical analyses and experimental tests indicated that in acidic copper plating solution Cu2+ ion could react with copper powder to form Cu + ion and the Cu + ion could react with chloride ion in the solution to produce cuprous chloride precipitation. When the initial mass concentration of the chloride ions in the acidic copper plating solution was 174 mg/L, the elimination rate of chloride ions after adding 1 g/L copper powders to the solution was 58.9% while that after adding 1 g/L zinc powders was 47.0%. This indicates that the treatment efficiency of chloride ion in the acidic copper plating solution with copper powders is higher than that with zinc powders.

  1. Modeling of the ionic transfers in saturated porous media: application to the penetration of chlorides through cementing materials; Modelisation des transferts ioniques dans les milieux poreux satures: application a la penetration des chlorures a travers les materiaux cimentaires

    Energy Technology Data Exchange (ETDEWEB)

    Khitab, Anwar

    2005-09-15

    In this work, the problem of ionic species transport through concrete porous media has been documented. Chloride ions penetration in cementitious materials is one of the processes widely responsible for the degradation of concrete structures. Therefore there exists an immense need for its correct understanding and quantification. Different research groups worldwide have proposed different chloride ingress models. Here, a one-dimensional model based on a multi-species approach of the ionic transport is presented. It is the new version of a previous model MsDiff developed a few years ago in our group that describes the diffusion of ionic species with the Nernst-Planck equation instead of Fick's laws. This newer version is named, the package version of MsDiff after it requires a package of five input data at any given age of concrete. With a multi-species approach, it is possible to take into account the interactions, which exist among different ionic species in pore solution of concrete. The numerical scheme of the model is based on finite difference method with Crank-Nickolson and Law-Wendroff techniques. In order to run MsDiff, we do need an input data. Several experiments were performed accordingly to provide experimental feedback to MsDiff. Standard immersion tests were conducted to validate the outcomes of MsDiff. Special attention is given to the diffusion coefficients of the ions and the interactions between the ionic species and the solid phase. In addition to MsDiff, some other existing models were also tried for the sake of comparison with the experimental chloride profiles. Certain experimentation was conducted to watch the effect of exposure period, concrete age at exposure and concentration in the environmental solution. In the end, the simulations were performed with MsDiff in order to calculate the chloride-induced corrosion initiation time using the experimental data already achieved while making use of different criteria adopted by different

  2. Cloreto isocianúrico e cloreto cianúrico: aspectos gerais e aplicações em síntese orgânica Isocyanuric chloride acid and cyanuric chloride: general aspects and applications in organic synthesis

    Directory of Open Access Journals (Sweden)

    Anna Claudia Cunha

    2006-06-01

    Full Text Available The aromatic six-membered heterocycles having three nitrogen atoms are denominated triazines. Among these heterocycles, isocyanuric chloride and cyanuric chloride are inexpensive and readily available 1,3,5-triazine derivatives, which have been attracting significant attention of organic chemists due to their different kinds of applications, which vary from pharmaceuticals to explosives. This short overview explores their uses in synthetic methods, as chlorinating and oxidating agents and some procedures for their preparation.

  3. [Classification of anticancer drugs with different mechanisms based on amino-acid consumption profiling in culture media].

    Science.gov (United States)

    Han, Xiaofei; Wang, Longxing; Yang, Qianxu; Xiao, Hongbin

    2011-04-01

    An approach for quantitative determination of amino-acid consumption profiling in culture media by high performance liquid chromatography with fluorescence detection (HPLC-FLD) was developed and validated, using o-phthalic dicarboxaldehyde (OPA) as the derivatizing reagent and norvaline as the internal standard. Mobile phase A was 10 mmol/L Na2HPO4Na2B4O7 buffer (pH 7.95), and mobile phase B was acetonitrile-methanol-water (45:45:10, v/v/v). The linear elution program was 5% B at the start and 52% B at the end in 35 min. The 17 free amino-acids (FAAs) were separated satisfactorily in 33 min. Following HeLa cells incubation in conditioned medias of taxol (4 micromol/L) and mitomycin (75 micromol/L), respectively, with control for 24 h, the media 17 amino-acid consumption profilings were determined, and then analyzed by multivariate statistical analysis based on Matlab7.1 software platform. Relation analysis performed by partial least squares-discriminant analysis (PLS-DA) indicated that in comparison with the control group, the media amino-acid consumption profiling can distinguish the two anticancer drugs with different mechanisms, which provides a new perspective for the pre-classification of drug action mechanisms during the screening of new anticancer drugs. Meanwhile, the idea from the outer into the inner has convenient and economic characteristics.

  4. Chloride transference during electrochemical chloride extraction process

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    Chemical titration method and lab-made chloride probes were jointly adopted to investigate the effects of water-to-cement (W/C) ratio and the impressed current density on chloride transport for cement-based materials during electrochemical chloride extraction (ECE) process.The dissolution of bound chlorides and the effect of current density on dissolution were analyzed.The variations of chloride concentration at different depths and the chloride transference process were monitored.Test results show that W/C ratios adopted have slight influence on chloride extraction,while chloride extraction efficiency is mainly determined by the impressed current density.During ECE process a portion of bound chloride ions dissolved and the amount of bound chlorides released is directly proportional to current density.

  5. Effects of organic phase, fermentation media, and operating conditions on lactic Acid extraction.

    Science.gov (United States)

    Hossain, Md Monwar; Maisuria, J L

    2008-01-01

    Lactic acid has extensive uses in the food, pharmaceutical, cosmetic and chemical industry. Lately, its use in producing biodegradable polymeric materials (polylactate) makes the production of lactic acid from fermentation broths very important. The major part of the production cost accounts for the cost of separation from very dilute reaction media where productivity is low as a result of the inhibitory nature of lactic acid. The current method of extraction/separation is both expensive and unsustainable. Therefore, there is great scope for development of alternative technology that will offer efficiency, economic, and environmental benefits. One of the promising technologies for recovery of lactic acid from fermentation broth is reactive liquid-liquid extraction. In this paper the extraction and recovery of lactic acid based on reactive processes is examined and the performance of a hydrophobic microporous hollow-fiber membrane module (HFMM) is evaluated. First, equilibrium experiments were conducted using organic solutions consisting of Aliquat 336/trioctylamine (as a carrier) and tri-butyl phosphate (TBP)/sunflower oil (as a solvent) The values of the distribution coefficient were obtained as a function of feed pH, composition of the organic phase (ratio of carrier to solvent), and temperature (range 8-40 degrees C). The optimum extraction was obtained with the organic phase consisting of a mixture of 15 wt % tri-octylamine (TOA) and 15% Aliquat 336 and 70% solvent. The organic phase with TBP performed best but is less suitable because of its damaging properties (toxicity and environmental impact) and cost. Sunflower oil, which performed moderately, can be regarded as a better option as it has many desirable characteristics (nontoxic, environment- and operator-friendly) and it costs much less. The percentage extraction was approximately 33% at pH 6 and at room temperature (can be enhanced by operating at higher temperatures) at a feed flow rate of 15-20 L

  6. Amino acid analysis by high-performance liquid chromatography after derivatization with 9-fluorenylmethyloxycarbonyl chloride Literature overview and further study.

    Science.gov (United States)

    Jámbor, A; Molnár-Perl, I

    2009-04-10

    A literature overview is given of HPLC methods currently in use to determine amino acids as their 9-fluorenylmethyloxycarbonyl (FMOC) derivatives. On the basis of the detailed literature overview an exhaustive derivatization study was performed with 22 amino acids, applying photodiode array (DAD) and fluorescence (FL) detection simultaneously, in order to clear up the controversial points of FMOC derivatization. Model investigations have been carried out as a function of the reaction time and reaction conditions, such as the molar concentration of the reagent, the molar ratios of the reactants, the pH and the solvent composition of the reaction medium. Special emphasis was put (i) on the evaluation of the blank values of the reagents, as a function of the composition and that of the pH of the reaction medium, (ii) on the unambiguous quantitation of all amino acids, including the less reactive aspartic and glutamic acids, as well as on the formation and transformation of histidine and tyrosine, existing partly, as single (N-FMOC-histidine, N-FMOC-tyrosine), partly as double labeled species (N,NH-FMOC-histidine, N,O-FMOC-tyrosine). Reproducibilities of 22 amino acids, including both histidine and tyrosine derivatives, obtained under optimum derivatization conditions are presented (at 0.5mM FMOC concentration corresponding to the molar ratios of [FMOC]/[amino acids](T)=5.5/1 (note: the superscript 'T' means the total of amino acids), with acetonitrile containing reagents, at pH 9, derivatization time=20 min), and characterized with the relative standard deviation percentages of their responses (acid FMOC derivatives proved to be 1 pmol, except for serine, glycine, valine (2.5 pmol), for cystine, N,NH-FMOC-histidine and for the total of N-FMOC-tyrosine and N,O-FMOC-tyrosine (5 pmol) and for tryptophan (10 pmol).

  7. Effect of polymer species and concentration on the production of mefenamic acid nanoparticles by media milling.

    Science.gov (United States)

    Ito, Atsutoshi; Konnerth, Christoph; Schmidt, Jochen; Peukert, Wolfgang

    2016-01-01

    The effect of four structurally different polymer species (hydroxypropylcellulose, polyvinylpyrrolidone, vinylpyrrolidone-vinyl acetate copolymer and polyvinyl alcohol) on the production of mefenamic acid nanoparticles during media milling has been studied. It was found that product particle sizes are strongly determined by the type of polymeric stabiliser as well as by its concentration at constant process conditions. With respect to small product particle sizes an optimum excipient concentration was identified and adjusted for colloidal stability of the drug nanosuspensions. Furthermore, it was found that overdosing of excipients must be omitted to suppress ripening due to enhanced solubilisation phenomena. Hence, the smallest product particle sizes were obtained using a polymeric stabiliser which exhibits a high affinity to the model drug compound and a low solubilisation capacity. Affinities of each polymer species to mefenamic acid and corresponding surface concentrations were determined using straightforward and simple viscosity measurements of the supernatant. A relationship between polymer affinity, solubilisation capacity and limiting product particle size has been observed, which supports the hypothesis that final product particle sizes are rather determined by the solid-liquid equilibrium than by pure mechanical fracture. Copyright © 2015 Elsevier B.V. All rights reserved.

  8. Oxidation of hydrogen peroxide by [NiIII(cyclam)]3+ in aqueous acidic media

    Indian Academy of Sciences (India)

    Sankaran Anuradha; Venkatapuram Ramanujam Vijayaraghavan

    2013-09-01

    The kinetics of oxidation of H2O2 by [NiIII(cyclam)]3+, [NiIIIL1], was studied in aqueous acidic media at 25°C and I = 0.5M (NaClO4). The [NiIIIL1] to [NiIIL1] reduction was found to be fast in the presence of Cu(II) ion than the oxidation of the cyclam ligand by ·OH. The rate constant showed an inverse acid dependence on H+ ion at the pH range 1-1.5. The presence of sulphate retards the reaction. Macrocylic ligand oxidation was followed spectrophotometrically by examining the oxidation of nickel(II) complexes of macrocyclic ligands such as 1,8-bis(2-hydroxyethyl)-1,3,6,8,10,13-hexaazacyclotetradecane (L2), -5,7,7,12,14,14-hexamethyl-1,4,8,11-tetraazacyclotetradecane (L3), rac-Me6[14]-4,11-dieneN4 (L4) by reaction with hydrogen peroxide. The rate constant for the cross reaction is discussed in terms of Marcus relationship.

  9. Inhibitive action of some plant extracts on the corrosion of steel in acidic media

    Energy Technology Data Exchange (ETDEWEB)

    Abdel-Gaber, A.M. [Department of Chemistry, Faculty of Science, Alexandria University, Ibrahimia, P.O. Box 426, Alexandria 21321 (Egypt)]. E-mail: ashrafmoustafa@yahoo.com; Abd-El-Nabey, B.A. [Department of Chemistry, Faculty of Science, Alexandria University, Ibrahimia, P.O. Box 426, Alexandria 21321 (Egypt); Sidahmed, I.M. [Department of Chemistry, Faculty of Science, Alexandria University, Ibrahimia, P.O. Box 426, Alexandria 21321 (Egypt); El-Zayady, A.M. [Department of Chemistry, Faculty of Science, Alexandria University, Ibrahimia, P.O. Box 426, Alexandria 21321 (Egypt); Saadawy, M. [Department of Chemistry, Faculty of Science, Alexandria University, Ibrahimia, P.O. Box 426, Alexandria 21321 (Egypt)

    2006-09-15

    The effect of extracts of Chamomile (Chamaemelum mixtum L.), Halfabar (Cymbopogon proximus), Black cumin (Nigella sativa L.), and Kidney bean (Phaseolus vulgaris L.) plants on the corrosion of steel in aqueous 1 M sulphuric acid were investigated by electrochemical impedance spectroscopy (EIS) and potentiodynamic polarization techniques. EIS measurements showed that the dissolution process of steel occurs under activation control. Potentiodynamic polarization curves indicated that the plant extracts behave as mixed-type inhibitors. The corrosion rates of steel and the inhibition efficiencies of the extracts were calculated. The results obtained show that the extract solution of the plant could serve as an effective inhibitor for the corrosion of steel in sulphuric acid media. Inhibition was found to increase with increasing concentration of the plant extract up to a critical concentration. The inhibitive actions of plant extracts are discussed on the basis of adsorption of stable complex at the steel surface. Theoretical fitting of different isotherms, Langmuir, Flory-Huggins, and the kinetic-thermodynamic model, were tested to clarify the nature of adsorption.

  10. Agar media that indicate acid production from sorbitol by oral microorganisms.

    Science.gov (United States)

    Kalfas, S; Edwardsson, S

    1985-12-01

    Two varieties of agar medium (Trypticase [BBL Microbiology Systems]-serum-sorbitol-bromcresol purple agar [TSSB] and Trypticase-blood-sorbitol-CaCO3 agar [TBSCa]) indicating microbial acid production from sorbitol were tested. The media were devised for use in studies on the prevalence of sorbitol-fermenting human oral microorganisms incubated in an anaerobic or microaerophilic atmosphere containing 5 to 6% CO2. TSSB contains bromcresol purple as the pH indicator and NaHCO3 as the main buffering salt. TBSCa contains CaCO3 as both the buffering salt and the indicator of acid production. The growth yield of pure cultures of oral microorganisms on TBSCa was shown to equal that on blood agar incubated under similar conditions. TSSB inhibited the growth of several bacteria to various extents. The recovery of sorbitol-fermenting microorganisms from oral specimens was the greatest when the specimens were assayed with TBSCa. The poorer results obtained with TSSB were mainly due to the decoloration of the pH indicator in this medium and the presence of greater numbers of sorbitol false-positive colonies.

  11. Noble metal-free bifunctional oxygen evolution and oxygen reduction acidic media electro-catalysts

    Science.gov (United States)

    Patel, Prasad Prakash; Datta, Moni Kanchan; Velikokhatnyi, Oleg I.; Kuruba, Ramalinga; Damodaran, Krishnan; Jampani, Prashanth; Gattu, Bharat; Shanthi, Pavithra Murugavel; Damle, Sameer S.; Kumta, Prashant N.

    2016-07-01

    Identification of low cost, highly active, durable completely noble metal-free electro-catalyst for oxygen reduction reaction (ORR) in proton exchange membrane (PEM) fuel cells, oxygen evolution reaction (OER) in PEM based water electrolysis and metal air batteries remains one of the major unfulfilled scientific and technological challenges of PEM based acid mediated electro-catalysts. In contrast, several non-noble metals based electro-catalysts have been identified for alkaline and neutral medium water electrolysis and fuel cells. Herein we report for the very first time, F doped Cu1.5Mn1.5O4, identified by exploiting theoretical first principles calculations for ORR and OER in PEM based systems. The identified novel noble metal-free electro-catalyst showed similar onset potential (1.43 V for OER and 1 V for ORR vs RHE) to that of IrO2 and Pt/C, respectively. The system also displayed excellent electrochemical activity comparable to IrO2 for OER and Pt/C for ORR, respectively, along with remarkable long term stability for 6000 cycles in acidic media validating theory, while also displaying superior methanol tolerance and yielding recommended power densities in full cell configurations.

  12. Does a Second Halogen Atom Affect the Nature of Intermolecular Interactions in Protic Acid-Haloethylene Complexes? in (Z)-1-CHLORO-2-FLUOROETHYLENE-HYDROGEN Chloride it Most Certainly DOES!

    Science.gov (United States)

    Tandon, Hannah K.; Leung, Helen O.; Marshall, Mark D.

    2016-06-01

    As part of a systematic study of the effect of chlorine substitution on the structures of protic acid-haloethylene complexes, the structure of the (Z)-1-chloro-2-fluoroethylene-hydrogen chloride complex has been investigated using ab initio quantum chemistry calculations and microwave spectroscopy. Although theory predicts a non-planar equilibrium structure for this species, it is only 6 cm-1 lower in energy than the planar geometry connecting the two equivalent minima on either side of the haloethylene plane, and the observed spectrum is consistent with a planar, average structure, likely the result of zero-point averaging. The geometry is unlike that of any previously characterized protic acid-haloethylene complex with a bifurcated primary interaction in which the hydrogen of the acid interacts with both the fluorine and the chlorine atoms on the haloethylene and there is no evidence for a secondary interaction involving the electron rich region of the acid. This structure can be contrasted to those of vinyl fluoride-hydrogen chloride (fluorine bound, planar ``top-binding,'' across the double bond), vinyl chloride-hydrogen chloride (chlorine bound, non-planar) and (Z)-1-chloro-2-fluoroethylene-acetylene (chlorine bound, planar ``side-binding,'' at one end of the double bond).

  13. Effect of the chloride ions on the hydrolysis of praseodymium in a 2M ion force media; Efecto de los iones cloruro sobre la hidrolisis del praseodimio en medio de fuerza ionica 2M

    Energy Technology Data Exchange (ETDEWEB)

    Lopez G, H.; Jimenez R, M.; Solache R, M.; Rojas H, A. [ININ, 52045 Ocoyoacac, Estado de Mexico (Mexico)

    2004-07-01

    The constants of the product of solubility and the first of hydrolysis were determined of the Praseodymium in media 2M of NaClO{sub 4} and 2M of NaCl, to 303 K and under conditions free of CO{sub 2}. The diagram of solubility was obtained (pPr{sub (ac)} - pC{sub H}), by means of a radiochemical method and with it was established the pC{sub H} that limit the saturation and non saturation areas; that diagram allowed, also, to calculate the constant of the product of solubility. Also, it was adjusted with the polynomial of solubility equation, that it allowed to determine and to check the values of the constants of the product of solubility and the first of hydrolysis. Independently, it was determined the first constant of hydrolysis of the element, by means of potentiometric titrations whose data were treated with the computer program named SUPERQUAD and with the adjustment of the equation of the average number of bonds. It was also calculates the log constant {beta}{sub Pr,Cl} of the specie PrCI{sup 2+} starting from the hydrolysis constants obtained in the perchlorate and chloride media. (Author)

  14. Synthesis of high molecular weight polylactic acid from aqueous lactic acid co-catalyzed by tin(II)chloride dihydrate and succinic anhydride

    Institute of Scientific and Technical Information of China (English)

    LEI Ziqiang; BAI Yanbin; WANG Shoufeng

    2005-01-01

    Polylactic acid was synthesized from commercial available cheap aqueous lactic acid (85%―90% w/w) using succinic anhydride and SnCl2·2H2O as catalyst in the absence of organic solvents. As a result, polylactic acid with a molecular weight of 60000 was prepared in 10 h. The new procedure is much simple, cheap and outstanding in that the start material is aqueous lactic acid; the catalytic system is environmentally benign.

  15. Incorporation of alpha-Ketoglutaric Acid as a Fixed Bed Scrubber Media for the Neutralization of Hydrazine Family Hypergolic Fuels

    Science.gov (United States)

    DeVor, R. W.; Santiago-Maldonado, E.; Parkerson, J. K.

    2010-01-01

    A candidate scrubber media, alpha-ketoglutaric acid (aKGA) adsorbed onto a silica-based substrate was examined as a potential alternative to the hydrazine-family hypergolic fuel neutralization techniques currently utilized at NASA/Kennedy Space Center (KSC). Helvenson et. al. has indicated that aKGA will react with hydrazines to produce non-hazardous, possibly biodegradable products. Furthermore, the authors have previously tested and demonstrated the use of aKGA aqueous solutions as a replacement neutralizing agent for citric acid, which is currently used as a scrubbing agent in liquid scrubbers at KSC. Specific properties examined include reaction efficiency, the loading capacity of aKGA onto various silica substrates, and the comparison of aKGA media performance to that of the citric acid vapor scrubber systems at KSC and a commercial vapor scrubber media. Preliminary investigations showed hydrophobic aerogel particles to be an ideal substrate for the deposition of the aKGA. Current studies have shown that the laboratory produced aKGA-Aerogel absorbent media are more efficient and cost effective than a commercially available fixed bed scrubber media, although much less cost effective than liquid-based citric acid scrubbers (although possibly safer and less labor intensive). A comparison of all three alternative scrubber technologies (liquid aKGA, solid-phase aKGA, and commercially available sorbent materials) is given considering both hypergolic neutralization capabilities and relative costs (as compared to the current citric acid scrubbing technology in use at NASA/KSC).

  16. A facile synthesis of novel optically active R,R-2-(4-(2-(4-(5-chloro-3-halo-pyridin-2-yloxy)-phenoxy)-propionyloxy)-phenoxy)-propionic acid esters using cyanuric chloride as potential herbicide

    Institute of Scientific and Technical Information of China (English)

    Hassan Tajik; Akbar Dadras; Shokufeh Aghabeygi

    2011-01-01

    A facile method for the synthesis of a new series of R,R-2-(4-(2-(4-(5-chloro-3-halopyridin-2-yloxy)-phenoxy)-propionyloxy)-phenoxy)-propionic acid ester derivatives containing a halo-substituted pyridine carrying two R,R chiral centers from (R)-2-(4-hydroxyphenoxy)propionic acid, halopyridines and alcohols using base/cyanuric chloride/catalyst system is reported. Their herbicidal activities against grass weeds and crops selectivity were evaluated.

  17. Uric acid level and its association with carotid intima-media thickness in patients with hypertension.

    Science.gov (United States)

    Tavil, Yusuf; Kaya, Mehmet Güngör; Oktar, Suna Ozhan; Sen, Nihat; Okyay, Kaan; Yazici, Hüseyin Uğur; Cengel, Atiye

    2008-03-01

    Carotid intima-media thickness (C-IMT) measured noninvasively by ultrasonography is now widely used as a surrogate marker for atherosclerotic disease and directly associated with increased risk of cardiovascular disease. Hyperuricemia (HU) is a well recognized risk factor for cardiovascular diseases. The independence of this association from other confounding factors has remained controversial. But the possible contributory effect of HU to carotid intima-media thickness (C-IMT) produced by hypertension (HT) has not been clarified yet. The study was designed to assess the C-IMT in patients with hypertension (HT) with or without HU. The study participants consisted of 30 patients (men 60%, mean age+/-S.D.: 49+/-11 years) with HT without HU, and 25 patients with HT and HU (men 52%, mean age+/-S.D.: 52+/-12 years), and 25 age-matched healthy control subjects (men 56%, mean age+/-S.D.: 50+/-13 years). All study groups were examined by B-mode ultrasound to measure the C-IMT at the far wall of the common carotid artery. C-IMT were significantly higher in the patient groups (HT without HU and HT with HU) compared to the control cases (0.70+/-0.14, 0.83+/-0.16 versus 0.57+/-0.16, mm, respectively, p<0.001). In the patients groups, patients with HU had significantly higher carotid IMT compared to the patients without HU. In stepwise linear regression analysis, we found that serum uric acid (SUA) levels independently but modestly associated with C-IMT (beta=0.42, p=0.002). We have shown that higher SUA levels are associated with atherogenesis independent from hypertension. Prospective studies will be necessary to confirm and extend these findings including early screening for hyperuricemia and lowering of SUA level looking at potential benefits in slowing progression of C-IMT in hypertensive patients.

  18. Synthesis of three-arm block copolymer poly(lactic-co-glycolic acid)–poly(ethylene glycol) with oxalyl chloride and its application in hydrophobic drug delivery

    Science.gov (United States)

    Zhu, Xiaowei; Liu, Chao; Duan, Jianwei; Liang, Xiaoyu; Li, Xuanling; Sun, Hongfan; Kong, Deling; Yang, Jing

    2016-01-01

    Purpose Synthesis of star-shaped block copolymer with oxalyl chloride and preparation of micelles to assess the prospect for drug-carrier applications. Materials and methods Three-arm star block copolymers of poly(lactic-co-glycolic acid) (3S-PLGA)–polyethylene glycol (PEG) were synthesized by ring-opening polymerization, then PEG as the hydrophilic block was linked to the terminal hydroxyl of 3S-PLGA with oxalyl chloride. Fourier-transform infrared (FT-IR) spectroscopy, gel-permeation chromatography (GPC), hydrogen nuclear magnetic resonance (1H-NMR) spectra, and differential scanning calorimetry were employed to identify the structure and properties of 3S-PLGA-PEG. Rapamycin (RPM)-loaded micelles were prepared by solvent evaporation, and pyrene was used as the fluorescence probe to detect the critical micelle concentration of the copolymer. The particle size, distribution, and ζ-potential of the micelles were determined by dynamic light scattering, and the morphology of the RPM-loaded micelles was analyzed by transmission electron microscopy. High-performance liquid chromatography was conducted to analyze encapsulation efficiency and drug-loading capacity, as well as the release behavior of RPM-loaded micelles. The biocompatibility of material and the cytostatic effect of RPM-loaded micelles were investigated by Cell Counting Kit 8 assay. Results FT-IR, GPC, and 1H-NMR suggested that 3S-PLGA-PEG was successfully synthesized. The RPM-loaded micelles prepared with the 3S-PLGA-PEG possessed good properties. The micelles had good average diameter and encapsulation efficiency. For in vitro release, RPM was released slowly from 3S-PLGA-PEG micelles, showing that 3S-PLGA-PEG-RPM exhibited a better and longer antiproliferative effect than free RPM. Conclusion In this study, we first used oxalyl chloride as the linker to synthesize 3S-PLGA-PEG successfully, and compared with reported literature, this method shortened the reaction procedure and improved the reaction

  19. Lewis Acid Pairs for the Activation of Biomass-derived Oxygenates in Aqueous Media

    Energy Technology Data Exchange (ETDEWEB)

    Roman, Yuriy [Massachusetts Inst. of Technology (MIT), Cambridge, MA (United States)

    2015-09-14

    The objective of this project is to understand the mechanistic aspects behind the cooperative activation of oxygenates by catalytic pairs in aqueous media. Specifically, we will investigate how the reactivity of a solid Lewis acid can be modulated by pairing the active site with other catalytic sites at the molecular level, with the ultimate goal of enhancing activation of targeted functional groups. Although unusual catalytic properties have been attributed to the cooperative effects promoted by such catalytic pairs, virtually no studies exist detailing the use heterogeneous water-tolerant Lewis pairs. A main goal of this work is to devise rational pathways for the synthesis of porous heterogeneous catalysts featuring isolated Lewis pairs that are active in the transformation of biomass-derived oxygenates in the presence of bulk water. Achieving this technical goal will require closely linking advanced synthesis techniques; detailed kinetic and mechanistic investigations; strict thermodynamic arguments; and comprehensive characterization studies of both materials and reaction intermediates. For the last performance period (2014-2015), two technical aims were pursued: 1) C-C coupling using Lewis acid and base pairs in Lewis acidic zeolites. Tin-, zirconium-, and hafnium containing zeolites (e.g., Sn-, Zr-, and Hf-Beta) are versatile solid Lewis acids that selectively activate carbonyl functional groups. In this aim, we demonstrate that these zeolites catalyze the cross-aldol condensation of aromatic aldehydes with acetone under mild reaction conditions with near quantitative yields. NMR studies with isotopically labeled molecules confirm that acid-base pairs in the Si-O-M framework ensemble promote soft enolization through α-proton abstraction. The Lewis acidic zeolites maintain activity in the presence of water and, unlike traditional base catalysts, in acidic solutions. 2) One-pot synthesis of MWW zeolite nanosheets for activation of bulky substrates. Through

  20. Production of Antilisterial Bacteriocins from Lactic Acid Bacteria in Dairy-Based Media: A Comparative Study.

    Science.gov (United States)

    Ünlü, Gülhan; Nielsen, Barbara; Ionita, Claudia

    2015-12-01

    One hundred and eight strains of lactic acid bacteria (LAB) were screened for bacteriocin production by the modified deferred antagonism and agar well diffusion methods. When the modified deferred antagonism method was employed, 82 LAB strains showed inhibitory action against Listeria monocytogenes v7 ½a, whereas 26 LAB strains expressed no inhibition. Only 12 LAB strains exhibited inhibitory activity when the agar well diffusion method was used, 11 of which had been previously recognized as bacteriocin production positive (Bac(+)). Lactobacillus viridescens NRRL B-1951 was determined, for the first time, to produce an inhibitory compound with a proteinaceous nature. The inhibitory activity was observed in the presence of lipase, α-chymotrypsin, and trypsin, but no inhibition zone could be detected in the presence of proteinase K, indicating the proteinaceous nature of the inhibitory compound. The inhibitory compound was active against Lact. sake ATCC 15521 and Lact. plantarum NCDO 995. Bacteriocin production by the Bac(+) LAB strains was assessed in Lactobacillus MRS Broth as well as in dairy-based media such as nonfat milk, demineralized whey powder, and cheddar cheese whey supplemented with complex nutrient sources that are rich in nitrogen. Lact. sake ATCC 15521 and L. monocytogenes CWD 1002, CWD 1092, CWD 1157, CWD 1198, and v7 ½a were used as indicators. The inhibitory activities of the bacteriocins varied depending on the indicator strains and the growth media used. The LAB indicator strains were found to be more sensitive to inhibition by bacteriocins when compared to the listerial indicator strains. Among the listerial indicators, L. monocytogenes CWD 1002 and CWD 1198 were the most sensitive strains to the bacteriocins investigated in this study. Media composition had a significant influence on bacteriocin production and activity. When compared to demineralized whey powder medium and cheddar cheese whey medium supplemented with whey protein concentrate

  1. Solvent extraction-separation of La(III), Eu(III) and Er(III) ions from aqueous chloride medium using carbamoyl-carboxylic acid extractants

    Institute of Scientific and Technical Information of China (English)

    Reyhaneh Safarbali; Mohammad Reza Yaftian; Abbasali Zamani

    2016-01-01

    N,N-dibutyldiglycol amic acid (HLI) and N,N-dioctyldiglycol amic acid (HLI) were synthesized and characterized by con-ventional spectroscopic methods. These molecules were examined as extractants for extraction-separation of La(III), Eu(III) and Er(III), as representative ions of light, middle and heavy rare earths, from aqueous chloride solutions. The analysis of the extraction equilibria revealed that the extracted species of lanthanum and europium ions by both of the extractants had a 1:3 metal to ligand ratio. It was suggested that erbium ions were extracted into the organic phase via the formation of Er(LI or I)2Cl complexes. The effect of the organic diluents on the extraction-separation efficiency of the studied rare earths by HLI and HLI was investigated by comparing the results obtained in dichloromethane and carbon tetrachloride. Regardless to the diluent used, the order of selectivity presented by the investigated extractants was Er(III)>Eu(III)>La(III). It is noteworthy that, a significant enhancement in separation of the studied rare earths by the extractants was achieved in their competitive extraction experiments with respect to that obtained in single component extraction experiments. Applicability of the extractants for the removal of rare earth ions from spent Ni-MH batteries was tested by removal of La(III), Eu(III) and Er(III) ions from simulated leach solution of such batteries.

  2. Alterations in blood pressure, antioxidant status and caspase 8 expression in cobalt chloride-induced cardio-renal dysfunction are reversed by Ocimum gratissimum and gallic acid in Wistar rats.

    Science.gov (United States)

    Akinrinde, A S; Oyagbemi, A A; Omobowale, T O; Asenuga, E R; Ajibade, T O

    2016-07-01

    The protective abilities of the chloroform extract of Ocimum gratissimum (COG) and gallic acid against cobalt chloride (CoCl2) - induced cardiac and renal toxicity were evaluated. Rats were exposed to CoCl2 (350ppm) for 7 days, either alone, or in combination with COG (100 and 200mg/kg) or gallic acid (120mg/kg). CoCl2 given alone, caused significant increases (pgallic acid treatment significantly reduced (pgallic acid by modulation of CoCl2-induced alterations in blood pressure, antioxidant status and pro-apoptotic caspase 8 in Wistar rats.

  3. 对氯水杨酸的纯度测定%Purity determination of salicylic acid chloride

    Institute of Scientific and Technical Information of China (English)

    杨丰科; 黄震

    2014-01-01

    采用双波长法对对氯水杨酸的纯度进行了测定。对氯水杨酸在乙醇中的最大吸收波长为243 nm,副产物等吸收总波长为267 nm。测定纯对氯水杨酸的标准纯度都超过99.5%,测定市售3种对氯水杨酸的纯度在97.8%~98.0%。研究表明,该方法操作简单,分析数据准确可靠。%Use dual-wavelength method to determine the purity of p-chlorine salicylic acid. The maximum absorption wavelength of p-chlorine salicylic acid in ethanol is 243 nm. The total absorption wavelength of byproducts is 267 nm. Determination of the standard purity of pure p-chlorine salicylic acid more than 99 . 5%. Determination of the purity of three kinds of commercially available p-chlorine salicylic acid was 97. 8 % ~98. 0 %. Studies show that the method is simple,the analytical data is accurate and reliable.

  4. Cellular mechanisms underlying the inhibitory effect of flufenamic acid on chloride secretion in human intestinal epithelial cells

    Directory of Open Access Journals (Sweden)

    Pawin Pongkorpsakol

    2017-06-01

    Full Text Available Intestinal Cl− secretion is involved in the pathogenesis of secretory diarrheas including cholera. We recently demonstrated that flufenamic acid (FFA suppressed Vibrio cholerae El Tor variant-induced intestinal fluid secretion via mechanisms involving AMPK activation and NF-κB-suppression. The present study aimed to investigate the effect of FFA on transepithelial Cl− secretion in human intestinal epithelial (T84 cells. FFA inhibited cAMP-dependent Cl− secretion in T84 cell monolayers with IC50 of ∼8 μM. Other fenamate drugs including tolfenamic acid, meclofenamic acid and mefenamic acid exhibited the same effect albeit with lower potency. FFA also inhibited activities of CFTR, a cAMP-activated apical Cl− channel, and KCNQ1/KCNE3, a cAMP-activated basolateral K+ channel. Mechanisms of CFTR inhibition by FFA did not involve activation of its negative regulators. Interestingly, FFA inhibited Ca2+-dependent Cl− secretion with IC50 of ∼10 μM. FFA inhibited activities of Ca2+-activated Cl− channels and KCa3.1, a Ca2+-activated basolateral K+ channels, but had no effect on activities of Na+–K+–Cl− cotransporters and Na+–K+ ATPases. These results indicate that FFA inhibits both cAMP and Ca2+-dependent Cl− secretion by suppressing activities of both apical Cl− channels and basolateral K+ channels. FFA and other fenamate drugs may be useful in the treatment of secretory diarrheas.

  5. Anti-inflammatory and anti-oxidative effects of alpha-lipoic acid in experimentally induced acute otitis media.

    Science.gov (United States)

    Tatar, A; Korkmaz, M; Yayla, M; Gozeler, M S; Mutlu, V; Halici, Z; Uslu, H; Korkmaz, H; Selli, J

    2016-07-01

    To investigate the anti-inflammatory, anti-oxidative and tissue protective effects, as well as the potential therapeutic role, of alpha-lipoic acid in experimentally induced acute otitis media. Twenty-five guinea pigs were assigned to one of five groups: a control (non-otitis) group, and otitis-induced groups treated with saline, penicillin G, alpha-lipoic acid, or alpha-lipoic acid plus penicillin G. Tissue samples were histologically analysed, and oxidative parameters in tissue samples were measured and compared between groups. The epithelial integrity was better preserved, and histological signs of inflammation and secretory metaplasia were decreased, in all groups compared to the saline treated otitis group. In the alpha-lipoic acid plus penicillin G treated otitis group, epithelial integrity was well preserved and histological findings of inflammation were significantly decreased compared to the saline, penicillin G and alpha-lipoic acid treated otitis groups. The most favourable oxidative parameters were observed in the control group, followed by the alpha-lipoic acid plus penicillin G treated otitis group. Alpha-lipoic acid, with its antioxidant, anti-inflammatory and tissue protective properties, may decrease the clinical sequelae and morbidity associated with acute otitis media.

  6. Behaviour of nickel and nickel oxide thin films in chloride media; Comportamiento de peliculas delgadas de niquel y oxido de niquel en NaCl al 3%

    Energy Technology Data Exchange (ETDEWEB)

    Magana, C. R.; Angeles, M. E.; Rodriguez, F. J.

    2006-07-01

    The aim of this work is to study the behaviour of both: a nickel thin film deposited on steel AISI 1018 (UNS G 10180) and a superior nickel oxide electrochemically obtained on the film; with the purpose of decreasing the corrosion rate of low carbon steel immersed in a solution of NaCl 3% wt, thus efficient anti corrosive protection could be obtained. Two film deposition techniques were used, electrochemical and magnetron DC sputtering; and the protective properties of deposited films exposed to the aggressive media, were evaluated. The characterization of different films was carried out by using electrochemical techniques: polarization curves and electrochemical impedance. (Author)

  7. Anthropogenically driven changes in chloride complicate interpretation of base cation trends in lakes recovering from acidic deposition.

    Science.gov (United States)

    Rosfjord, Catherine H; Webster, Katherine E; Kahl, Jeffrey S; Norton, Stephen A; Fernandez, Ivan J; Herlihy, Alan T

    2007-11-15

    Declines in Ca and Mg in low ANC lakes recovering from acidic deposition are widespread across the northern hemisphere. We report overall increases between 1984 and 2004 in the concentrations of Ca + Mg and Cl in lakes representing the statistical population of nearly 4000 low ANC lakes in the northeast U.S. Increases in Cl occurred in nearly all lakes in urbanized southern New England, but only 18% of lakes in more remote Maine had Cl increases. This spatial pattern implicates road salt application as the major source of the increased Cl salts. Among the 48% of the lake population classified as salt-affected, the median changes in Cl (+133 microeq/L) and Ca + Mg (+47 microeq/ L) were large and positive in direction over the 20 years. However, in the unaffected lakes, Cl remained stable and Ca + Mg decreased (-3 microeq/L), consistent with reported long-term trends in base cations of acid-sensitive lakes. This discrepancy between the Cl groups suggests that changes in ion exchange processes in salt-affected watersheds have altered the geochemical cycling of Ca and Mg. One policy-relevant implication is that waters influenced by Cl salts complicate regional assessments of surface water recovery from "acid rain" related to the passage of the Clean Air Act.

  8. Physiochemical Studies of Sodium Chloride on Mungbean (Vigna radiata L. Wilczek and Its Possible Recovery with Spermine and Gibberellic Acid

    Directory of Open Access Journals (Sweden)

    Srijita Ghosh

    2015-01-01

    Full Text Available The physiological and biochemical responses to increasing NaCl concentrations, along with low concentrations of gibberellic acid or spermine, either alone or in their combination, were studied in mungbean seedlings. In the test seedlings, the root-shoot elongation, biomass production, and the chlorophyll content were significantly decreased with increasing NaCl concentrations. Salt toxicity severely affected activities of different antioxidant enzymes and oxidative stress markers. Activities of antioxidant enzymes, superoxide dismutase (SOD, and catalase (CAT increased significantly over water control. Similarly, oxidative stress markers such as proline, malondialdehyde (MDA, and hydrogen peroxide (H2O2 contents also increased as a result of progressive increase in salt stress. Combined application of NaCl along with low concentrations of either gibberellic acid (5 µM or spermine (50 µM in the test seedlings showed significant alterations, that is, drastic increase in seedling elongation, increased biomass production, increased chlorophyll content, and significant lowering in all the antioxidant enzyme activities as well as oxidative stress marker contents in comparison to salt treated test seedlings, leading to better growth and metabolism. Our study shows that low concentrations of either gibberellic acid or spermine will be able to overcome the toxic effects of NaCl stress in mungbean seedlings.

  9. Tribenzylammonium chloride

    Directory of Open Access Journals (Sweden)

    Waly Diallo

    2014-05-01

    Full Text Available Single crystals of the title salt, C21H21NH+·Cl−, were isolated as a side product from the reaction involving [(C6H5CH23NH]2[HPO4] and Sn(CH33Cl in ethanol. Both the cation and the anion are situated on a threefold rotation axis. The central N atom in the cation has a slightly distorted tetrahedral environment, with angles ranging from 107.7 to 111.16 (10°. In the crystal, the tribenzylammonium cations and chloride anions are linked through N—H...Cl and C—H...Cl hydrogen bonds, leading to the formation of infinite chains along [001]. The crystal studied was a merohedral twin.

  10. 钢管酸洗液制作聚氯化铁的方法与应用%Study on Poly Ferric Chloride from Steel Pickling Acid Waste

    Institute of Scientific and Technical Information of China (English)

    辛胜

    2012-01-01

    利用钢管酸洗液制备了一种高效无机絮凝剂一聚合氯化铁,对制作工艺进行了研究并对实际效果进行了验证。研究结果表明:根据盐酸洗管废液中游离酸与铁的含量,采用铁屑等含铁原料调整铁的含量,加入聚合稳定剂与原料充分反应后,加入聚合氧化剂进行氧化聚合,最后用盐酸来调整盐基度。制备的高浓度聚合氯化铁具有比聚合硫酸铁更好的混凝除浊的能力,并便于贮存,适用于给水及污水处理。%The preparing method and effect of inorganic polymer flocculant poly - ferric chloride was explored from steel pickling acid waste. The results showed that the mass proportion of Fe^2 + could be controlled according to the free acidity and Fe^2+ in steel pickling acid waste. After addition of poly - stabilizer and raw materials with oxidants, the average basicity was adjusted by HCI. The product could be applied in treating low turbidity water, the waste water of synthetic detergent.

  11. Lipase in biphasic alginate beads as a biocatalyst for esterification of butyric acid and butanol in aqueous media.

    Science.gov (United States)

    Ng, Choong Hey; Yang, Kun-Lin

    2016-01-01

    Esterification of organic acids and alcohols in aqueous media is very inefficient due to thermodynamic constraints. However, fermentation processes used to produce organic acids and alcohols are often conducted in aqueous media. To produce esters in aqueous media, biphasic alginate beads with immobilized lipase are developed for in situ esterification of butanol and butyric acid. The biphasic beads contain a solid matrix of calcium alginate and hexadecane together with 5 mg/mL of lipase as the biocatalyst. Hexadecane in the biphasic beads serves as an organic phase to facilitate the esterification reaction. Under optimized conditions, the beads are able to catalyze the production of 0.16 mmol of butyl butyrate from 0.5 mmol of butyric acid and 1.5 mmol of butanol. In contrast, when monophasic beads (without hexadecane) are used, only trace amount of butyl butyrate is produced. One main application of biphasic beads is in simultaneous fermentation and esterification (SFE) because the organic phase inside the beads is very stable and does not leach out into the culture medium. SFE is successfully conducted with an esterification yield of 6.32% using biphasic beads containing iso-octane even though the solvent is proven toxic to the butanol-producing Clostridium spp.

  12. Competition between Hydrogen Evolution and Carbon Dioxide Reduction on Copper Electrodes in Mildly Acidic Media.

    Science.gov (United States)

    Ooka, Hideshi; Figueiredo, Marta C; Koper, Marc T M

    2017-09-19

    Understanding the competition between hydrogen evolution and CO2 reduction is of fundamental importance to increase the faradaic efficiency for electrocatalytic CO2 reduction in aqueous electrolytes. Here, by using a copper rotating disc electrode, we find that the major hydrogen evolution pathway competing with CO2 reduction is water reduction, even in a relatively acidic electrolyte (pH 2.5). The mass-transport-limited reduction of protons takes place at potentials for which there is no significant competition with CO2 reduction. This selective inhibitory effect of CO2 on water reduction, as well as the difference in onset potential even after correction for local pH changes, highlights the importance of differentiating between water reduction and proton reduction pathways for hydrogen evolution. In-situ FTIR spectroscopy indicates that the adsorbed CO formed during CO2 reduction is the primary intermediate responsible for inhibiting the water reduction process, which may be one of the main mechanisms by which copper maintains a high faradaic efficiency for CO2 reduction in neutral media.

  13. Inhibitory Effect of Kopsia Singapurensis Extract on the Corrosion Behavior of Mild Steel in Acid Media

    Institute of Scientific and Technical Information of China (English)

    RAJA Pandian Bothi; RAHIM Afidah Abdul; OSMAN Hasnah; AWANG Khalijah

    2010-01-01

    The influence of the alkaloid extract of Kopsia singapurensis on the corrosion behavior of mild steel (MS) in 1 mol·L-1 HC1 and 1 mol·L-1 H2SO4 was studied using electrochemical techniques,viz.,potentiodynamic polarization and AC impedance.The experimental results clearly show that the plant extract effectively inhibits corrosion in both acid media and the inhibition efficiency obtained from the electrochemical techniques is in good agreement.Furthermore,the polarization technique indicates that the extract acts as an anodic type inhibitor in HC1 and as a mixed type in H2SO4 Scanning election microscopy (SEM) was carried out to examine the surface morphological changes of metal specimens in both the inhibited and uninhibited solutions.SEM images show the formation of an adsorbed layer over the metal surface by the inhibitor molecule.The presence of alkaloidal constituents in the plant extract was confirmed by Fourier transform infrared (FTIR) spectroscopy and chemical analysis.

  14. Electrochemical evaluation of inhibition efficiency of ciprofloxacin on the corrosion of copper in acid media

    Energy Technology Data Exchange (ETDEWEB)

    Thanapackiam, P. [Department of Chemistry, Coimbatore Institute of Technology, Coimbatore, Tamilnadu, 641 014 (India); Rameshkumar, Subramaniam [Department of Chemistry, Sri Vasavi College, Erode, Tamilnadu, 638 316 (India); Subramanian, S.S. [Department of Chemistry, PSG College of Technology, Coimbatore, Tamilnadu, 641 004 (India); Mallaiya, Kumaravel, E-mail: mkvteam.research@gmail.com [Department of Chemistry, PSG College of Technology, Coimbatore, Tamilnadu, 641 004 (India)

    2016-05-01

    The inhibition efficiency of ciprofloxacin on the corrosion of copper was studied in 1.0MHNO{sub 3} and 0.5MH{sub 2}SO{sub 4} solutions by electrochemical impedance spectroscopy and potentiodynamic polarization techniques. The corrosion inhibition action of ciprofloxacin was observed to be of mixed type in both the acid media, but with more of a cathodic nature. The experimental data were found to fit well with the Langmuir adsorption isotherm. The thermodynamic parameters such as adsorption equilibrium constant(K{sub ads}), free energy of adsorption(ΔG{sub ads}), activation energy(E{sub a}) and potential of zero charge(PZC) showed that the adsorption of ciprofloxacin onto copper surface involves both physisorption and chemisorption. - Highlights: • The inhibitor efficiency increases with increase in ciprofloxacin concentration. • Polarization measurements show that ciprofloxacin acts as a mixed type inhibitor. • The adsorption of the inhibitor on copper surface follows Langmuir adsorption isotherm. • The negative values of ΔG{sub ads} indicates that the adsorption is spontaneous and exothermic.

  15. Development of a new colorimetric assay for detection of bisphenol-A in aqueous media using green synthesized silver chloride nanoparticles: experimental and theoretical study.

    Science.gov (United States)

    Khalililaghab, Shiva; Momeni, Safieh; Farrokhnia, Maryam; Nabipour, Iraj; Karimi, Sadegh

    2017-02-08

    In the present study, a cost-effective, green and simple synthesis method was applied for preparation of stable silver chloride nanoparticles (AgCl-NPs). The method was done by forming AgCl-NPs from Ag(+) ions using aqueous extract of brown algae (Sargassum boveanum) obtained from the Persian Gulf Sea. This extract served as capping agent during the formation of AgCl-NPs. Creation of AgCl-NPs was confirmed by UV-visible spectroscopy, powder X-ray diffraction, energy-dispersive X-ray spectroscopy, and high-resolution transmission electron microscopy, while the morphology and size analyses were characterized using high-resolution transmission electron microscopy and dynamic light scattering. After optimization of some experimental conditions, particularly pH, a simple and facile system was developed for the naked-eye detection of bisphenol-A. Moreover, a theoretical study of AgCl interaction with bisphenol-A was performed at the density functional level of theory in both gas and solvent phases. Theoretical results showed that electrostatic and van der Waal interactions play important roles in complexation of bisphenol-A with AgCl-NPs, which can lead to aggregation of the as-prepared AgCl-NPs and results in color change from specific yellow to dark purple, where a new aggregation band induced at 542 nm appears. The absorbance at 542 nm was found to be linearly dependent on the bisphenol-A concentration in the range of 1 × 10(-6)-1 × 10(-4) M, with limit of detection of 45 nM. In conclusion, obtained results from the present study can open up an innovative application of the green synthesis of AgCl-NPs using brown algae extract as colorimetric sensors.

  16. Use of Nonspecific, Glutamic Acid-Free, Media and High Glycerol or High Amylase as Inducing Parameters for Screening Bacillus Isolates Having High Yield of Polyglutamic Acid.

    Science.gov (United States)

    Baxi, Nandita N

    2014-01-01

    Out of fifty-five Bacillus isolates obtained from ten different regional locations and sources, seven showed the ability to consistently produce specific extracellular polymeric substance (EPS) on rich as well as synthetic but nonspecific media which did not contain glutamic acid. The isolates were identified as either Bacillus licheniformis or Bacillus subtilis. The EPS from all isolates was resistant to alpha protease, proteinase K, and was thus of high molecular weight. Further it was detected after SDS-PAGE by methylene blue but not by coomassie blue R staining as in case of proteins with high proportion of acidic amino acids. Cell-free EPS, after acid hydrolysis, showed absence of carbohydrates and presence of only glutamic acid. Thus the native the EPS from all seven isolates was confirmed to be gamma polyglutamic acid (PGA) and not exopolysaccharide. The Bacillus isolate T which produced maximum polymer on all media tested had higher amylase: protease activity as compared to other strains. If inoculum was developed in rich medium as compared to synthetic medium, the PGA produced increased by twofold in the subsequent synthetic production medium. Similarly, use of inoculum consisting of young and vegetative cells also increased the PGA production by twofold though amount of inoculum did not affect yield of PGA. Though PGA was produced in even in the absence of glutamic acid supplementation in the production medium by all isolates, the yield of PGA increased by fourfold in the presence glutamic acid and the maximum yield was 30 g/l for isolate K. The supplementation of glutamine instead of glutamic acid into the medium caused an increase in the viscosity of the non-Newtonian solution of PGA.

  17. Carbon nanotube/raspberry hollow Pd nanosphere hybrids for methanol, ethanol, and formic acid electro-oxidation in alkaline media.

    Science.gov (United States)

    Liu, Zhelin; Zhao, Bo; Guo, Cunlan; Sun, Yujing; Shi, Yan; Yang, Haibin; Li, Zhuang

    2010-11-01

    In this paper, raspberry hollow Pd nanospheres (HPNs)-decorated carbon nanotube (CNT) was developed for electro-oxidation of methanol, ethanol, and formic acid in alkaline media. The electrocatalyst was fabricated simply by attaching HPNs onto the surface of CNT which had been functionalized by polymer wrapping. The as-prepared HPN-CNTs (CHPNs) were characterized by transmission electron microscopy (TEM), scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDX), and X-ray photoelectron spectroscopy (XPS). The increasing interest and intensive research on fuel cell inspire us to investigate the electrocatalytic properties of the prepared nanostructures. Besides that, previous reports about alkaline other than acidic media could supply a more active environment guide us to examine the electrocatalytic properties in alkaline electrolyte. It is found that this novel hybrid electrocatalyst exhibits excellent electrocatalytic properties and can be further applied in fuel cells, catalysts, and sensors. Copyright 2010 Elsevier Inc. All rights reserved.

  18. Does a Second Halogen Atom Affect the Nature of Intermolecular Interactions in Protic Acid-Haloethylene Complexes? in (E)-1-CHLORO-2-FLUOROETHYLENE-HYDROGEN Chloride it Depends on how you Look at it

    Science.gov (United States)

    Leung, Helen O.; Marshall, Mark D.

    2016-06-01

    As part of a systematic study of the effect of chlorine substitution on the structures of protic acid haloethylene complexes, the structure of the (E)-1-chloro-2-fluoroethylene-hydrogen chloride complex has been investigated using ab initio quantum chemistry calculations and microwave spectroscopy. Although theory predicts a non-planar equilibrium structure for this species, it is only 7 cm-1 lower in energy than the planar geometry connecting the two equivalent minima on either side of the haloethylene plane, and the observed spectrum is consistent with a planar, average structure, likely the result of zero-point averaging. The geometry is very similar to the fluorine binding, vinyl fluoride-hydrogen chloride complex, suggesting that the substitution of chlorine for a hydrogen trans to the fluorine atom has very little effect on intermolecular interactions in this case. On the other hand, vinyl chloride-hydrogen chloride adopts a non-planar, chlorine binding configuration so that alternatively one could say that the presence of fluorine has a large effect on protic acid-chlorine interactions.

  19. Corrosion resistance of flaky aluminum pigment coated with cerium oxides/hydroxides in chloride and acidic electrolytes

    Science.gov (United States)

    Niroumandrad, S.; Rostami, M.; Ramezanzadeh, B.

    2015-12-01

    The objective of this study was to enhance the corrosion resistance of lamellar aluminum pigment through surface treatment by cerium oxides/hydroxides. The surface composition of the pigments was studied by energy-dispersive spectroscopy (EDS) and X-ray photoelectron spectroscopy (XPS). The corrosion resistance of the pigment was evaluated by conventional hydrogen evolution measurements in acidic solution and electrochemical impedance spectroscopy (EIS) in 3.5% NaCl solution. Results showed that the Ce-rich coating composed of Ce2O3 and CeO2 was precipitated on the pigment surface after immersion in the cerium solution. The corrosion resistance of pigment was significantly enhanced after modification with cerium layer.

  20. Protective effects of kolaviron and gallic acid against cobalt-chloride-induced cardiorenal dysfunction via suppression of oxidative stress and activation of the ERK signaling pathway.

    Science.gov (United States)

    Akinrinde, Akinleye Stephen; Omobowale, Olutayo; Oyagbemi, Ademola; Asenuga, Ebunoluwa; Ajibade, Temitayo

    2016-12-01

    Cobalt (Co) toxicity is a potential public health problem due to recent renewed use of Co in orthopedic implants, dietary supplements, and blood doping in athletes and horses. We investigated the protective roles of kolaviron (KV), a bi-flavonoid of Garcinia kola, and gallic acid (GA) on cobalt chloride (CoCl2)-induced cardiorenal damage in rats. CoCl2 caused significant increases (p < 0.05) in serum creatine kinase-myocardial band (CK-MB), lactate dehydrogenase (LDH), aspartate transaminase (AST), xanthine oxidase (XO), urea, creatinine, malondialdehyde, H2O2, nitric oxide, as well as C-reactive protein expression, along with significant (p < 0.05) reduction in cardiac and renal expression of extracellular signal regulated kinase (ERK) and the activities of superoxide dismutase, catalase, and glutathione S-transferase. KV and GA prevented the toxic effects of CoCl2 by stimulating ERK expression and reversing Co-induced biochemical changes. Administration of CoCl2 alone did not significantly alter ECG patterns in the rats, although co-treatment with KV (200 mg/kg) produced QT-segment prolongation and also appeared to potentiate Co hypotension. Histopathology of the heart and kidneys of rats treated with KV and GA confirmed the biochemical data. KV and GA thus protected against cardiac and renal damage in Co intoxication via antioxidant and (or) cell survival mechanisms, possibly involving ERK activation.

  1. Potent in vitro synergism of fusidic acid (FA) and berberine chloride (BBR) against clinical isolates of methicillin-resistant Staphylococcus aureus (MRSA).

    Science.gov (United States)

    Liang, Rong-mei; Yong, Xiao-lan; Duan, Yu-qin; Tan, Yong-hong; Zeng, Ping; Zhou, Zi-ying; Jiang, Yan; Wang, Shi-hua; Jiang, Yun-ping; Huang, Xiao-chun; Dong, Zhao-hui; Hu, Ting-ting; Shi, Hui-qing; Li, Nan

    2014-11-01

    It was found in the present study that combined use of fusidic acid (FA) and berberine chloride (BBR) offered an in vitro synergistic action against 7 of the 30 clinical methicillin-resistant Staphylococcus aureus (MRSA) strains, with a fractional inhibitory concentration (FIC) index ranging from 0.5 to 0.19. This synergistic effect was most pronounced on MRSA 4806, an FA-resistant isolate, with a minimum inhibitory concentration (MIC) value of 1,024 μg/ml. The time-kill curve experiment showed that FA plus BBR yielded a 4.2 log10 c.f.u./ml reduction in the number of MRSA 4806 bacteria after 24-h incubation as compared with BBR alone. Viable count analysis showed that FA plus BBR produced a 3.0 log10 c.f.u./ml decrease in biofilm formation and a 1.5 log10 c.f.u./ml decrease in mature biofilm in viable cell density as compared with BBR alone. In addition, phase contrast micrographs confirmed that biofilm formation was significantly inhibited and mature biofilm was obviously destructed when FA was used in combination with BBR. These results provide evidence that combined use of FA and BBR may prove to be a promising clinical therapeutic strategy against MRSA.

  2. Surface-enhanced Raman scattering and atomic force microscopy of brass electrodes in sulfuric acid solution containing benzotriazole and chloride ion

    Energy Technology Data Exchange (ETDEWEB)

    Rubim, J.C.; Kim, J.; Henderson, E.; Cotton, T.M. (Instituto de Quimica da Universidade de Sao Paulo (Brazil) Ames Lab., IA (United States) Iowa State Univ., Ames (United States))

    1993-01-01

    Three different methods were used to roughen brass (Cu/Zn = 67/33) electrodes in 0.5 M H[sub 2]SO[sub 4] containing 1.0 mM benzotriazole (BTAH): (1) polarization at +0.05 V vs. saturated calomel for 5 min; (2) immersion in the above solution for six hours; and (3) oxidation-reduction cycling in the presence of chloride ion. The surfaces prepared by the first two methods exhibited surface-enhanced Raman scattering (SERS) spectra of the polymeric complex [Cu(I)BTA][sub s]. The SERS spectrum obtained from electrodes prepared by the third method is very similar to that of [Cu(I)CIBTAH][sub 4]. Examination of the electrodes by atomic force microscopy (AFM) showed that a large number of grain boundary sites are formed by the roughening processes. This effect is attributed to the loss of zinc, which occurs during corrosion of the mirror-like, polished brass electrode surface in the sulfuric acid solution. 11 refs., 5 figs.

  3. Surface characterization of poly(vinyl chloride) urinary catheters functionalized with acrylic acid and poly(ethylene glycol) methacrylate using gamma-radiation

    Science.gov (United States)

    Islas, Luisa; Ruiz, Juan-Carlos; Muñoz-Muñoz, Franklin; Isoshima, Takashi; Burillo, Guillermina

    2016-10-01

    Poly(vinyl chloride) (PVC) urinary catheters were modified with either a single or binary graft of acrylic acid (AAc) and/or poly(ethylene glycol) methacrylate (PEGMA) using gamma-radiation from 60Co to obtain PVC-g-AAc, PVC-g-PEGMA, [PVC-g-AAc]-g-PEGMA, and [PVC-g-PEGMA]-g-AAc copolymers. The outer and inner surfaces of the modified catheters were characterized using scanning electron microscopy (SEM), confocal laser microscopy (CLM) and X-ray photoelectron spectroscopy (XPS). The XPS analyses, by examining the correlation between the variation of the C1s and O1s content at the catheter's surface, revealed that the catheter's surfaces were successfully grafted with the chosen compounds, with those that were binary grafted showing a slightly more covered surface as was evidenced by the disappearance of PVC's Cl peak. The SEM and CLM analyses revealed that catheters that had been grafted with PEGMA had a rougher outer surface as compared to those that had only been grafted with AAc. In addition, these imaging techniques showed that the inner surface of the singly grafted catheters, whether they had been grafted with AAc or PEGMA, retained some smoothness at the analyzed grafting percentages, while the binary grafted catheters showed many protuberances and greater roughness on both outer and inner surfaces.

  4. pH dependent poly[2-(methacryloyloxyethyl)trimetylammonium chloride-co-methacrylic acid]hydrogels for enhanced targeted delivery of 5-fluorouracil in colon cancer cells.

    Science.gov (United States)

    Mishra, R K; Ramasamy, K; Ahmad, N A; Eshak, Z; Majeed, A B A

    2014-04-01

    Stimuli responsive hydrogels have shown enormous potential as a carrier for targeted drug delivery. In this study we have developed novel pH responsive hydrogels for the delivery of 5-fluorouracil (5-FU) in order to alleviate its antitumor activity while reducing its toxicity. We used 2-(methacryloyloxyethyl) trimetylammonium chloride a positively charged monomer and methacrylic acid for fabricating the pH responsive hydrogels. The released 5-FU from all except hydrogel (GEL-5) remained biologically active against human colon cancer cell lines [HT29 (IC50 = 110-190 μg ml(-1)) and HCT116 (IC50 = 210-390 μg ml(-1))] but not human skin fibroblast cells [BJ (CRL2522); IC50 ≥ 1000 μg ml(-1)]. This implies that the copolymer hydrogels (1-4) were able to release 5-FU effectively to colon cancer cells but not normal human skin fibroblast cells. This is probably due to the shorter doubling time that results in reduced pH in colon cancer cells when compared to fibroblast cells. These pH sensitive hydrogels showed well defined cell apoptosis in HCT116 cells through series of events such as chromatin condensation, membrane blebbing, and formation of apoptotic bodies. No cell killing was observed in the case of blank hydrogels. The results showed the potential of these stimuli responsive polymer hydrogels as a carrier for colon cancer delivery.

  5. Extraction Equilibrium of Mn2+, Ca2+, and Mg2+ from Chloride Solutions by Di(2-ethylhexyl)phosphoric Acid Dissolved in Kerosene

    Science.gov (United States)

    Zhang, Chuanfu; Cao, Wenxin; Zhan, Jing; Ding, Fenghua; Hwang, Jiann-Yang

    2015-05-01

    The presence of calcium and magnesium affects the purity of the final product MnCl2 in hydrometallurgical treatment processes. The solvent extraction method can be used to separate Ca2+ and Mg2+ from Mn2+ solutions containing impurity ions such as Ca2+ and Mg2+. This article aims to investigate the single-stage extraction equilibrium of Ca2+, Mg2+, and Mn2+ in chloride medium using di(2-ethylhexyl)phosphoric acid in kerosene (O:A = 1:1). The results show that the pH0.5 values are 1.11, 1.56, and 2.18 for Ca2+, Mn2+, and Mg2+, respectively. The mechanism of extraction and stoichiometries of metal-containing extracted species were illustrated based on a slope analysis. The composition of the extracted species in the organic phase is proposed to be MnR2·R2H2, CaR2·R2H2, and MgR2·(R2H2)2, respectively.

  6. Metal chloride hydrates as Lewis acid catalysts in multicomponent synthesis of 2,4,5-triarylimidazoles or 2,4,5-triaryloxazoles

    Energy Technology Data Exchange (ETDEWEB)

    Marques, Marcelo V. [Departamento de Engenharia de Processos, Fundacao de Ciencia e Tecnologia, Cachoeirinha, RS (Brazil); Russowsky, Dennis, E-mail: dennis@iq.ufrgs.br [Laboratorio de Sinteses Organicas, Instituto de Quimica, Universidade Federal do Rio Grande do Sul, Porto Alegre-RS (Brazil); Ruthner, Marcelo M.; Fontoura, Luiz A.M. [Curso de Quimica, Universidade Luterana do Brasil, Canoas, RS (Brazil)

    2012-07-01

    A series of nine metal chloride hydrates (ZnCl{sub 2}.2H{sub 2}O, SnCl{sub 2}.2H{sub 2}O, CdCl{sub 2}.2H{sub 2}O, MnCl{sub 2}.4H{sub 2}O, CoCl{sub 2}.6H{sub 2}O, SrCl{sub 2}.6H{sub 2}O, NiCl{sub 2}.6H{sub 2}O, CrCl{sub 3}.6H{sub 2}O and CeCl{sub 3}.7H{sub 2}O) was investigated as mild and inexpensive Lewis acid catalysts to promote the multicomponent synthesis of triarylimidazoles. Reactions starting from benzil showed the best results when SnCl{sub 2}.2H{sub 2}O was used, while for benzoin as the starting material, CeCl{sub 3}.7H{sub 2}O was more efficient. All reactions were performed in EtOH as solvent. These catalysts were also successfully employed in the synthesis of triaryloxazoles. (author)

  7. Rapid and nondestructive analysis of phthalic acid esters in toys made of poly(vinyl chloride) by direct analysis in real time single-quadrupole mass spectrometry.

    Science.gov (United States)

    Rothenbacher, Thorsten; Schwack, Wolfgang

    2009-09-01

    In the European Community, selected phthalic acid esters (PAE) are restricted in their use for the manufacture of toys and childcare articles to a content of 0.1% by weight. As PAE are mainly used as plasticisers for poly(vinyl chloride) (PVC), a rapid screening method for PVC samples with direct analysis in real time ionisation and single-quadrupole mass spectrometry (DART-MS) was developed. Using the ions for the protonated molecules, a limit of detection (LOD) of 0.05% was obtained for benzyl butyl phthalate, bis(2-ethylhexyl) phthalate and diisononyl phthalate, while for dibutyl phthalate, di-n-octyl phthalate and diisodecyl phthalate the LOD was 0.1%. Validation of identification by the presence of ammonium adducts and characteristic fragment ions was possible to a content of >or=1% for all PAE, except for benzyl butyl phthalate (>or=5%). Based on the fragment ions, bis(2-ethylhexyl) phthalate could clearly be distinguished from di-n-octyl phthalate, if the concentrations were >r=5% and >or=1% at measured DART helium temperatures of 130 and 310 degrees C, respectively. The complete analysis of one sample only took about 8 min. At the generally used gas temperature of 130 degrees C, most toy and childcare samples did not sustain damage if their shape fitted into the DART source. Copyright (c) 2009 John Wiley & Sons, Ltd.

  8. Synergistic bactericidal action of phytic acid and sodium chloride against Escherichia coli O157:H7 cells protected by a biofilm.

    Science.gov (United States)

    Kim, Nam Hee; Rhee, Min Suk

    2016-06-16

    The food industry must prevent the build-up of strong Escherichia coli O157:H7 biofilms in food processing environments. The present study examined the bactericidal action of phytic acid (PA), a natural extract from rice bran and the hulls/peels of legumes, against E. coli O157:H7 biofilms. The synergistic bactericidal effects of PA plus sodium chloride (NaCl) were also examined. E. coli O157:H7 biofilms were allowed for form on stainless steel coupons by culture in both rich (tryptic soy broth, TSB) and minimal (M9) medium at 22°C for 6days. Bacterial cells within biofilms grown in M9 medium were significantly more resistant to PA than those grown in TSB (pbiofilm effect of PA was significantly increased by addition of NaCl (2-4%) (pbiofilms without recovery (a>6.5logCFU/cm(2) reduction). Neither PA nor NaCl alone were this effective (PA, 1.6-2.7logCFU/cm(2) reduction; NaCl, food safety managers who encounter thick biofilm formation in food processing environments.

  9. A single amino-acid substitution toggles chloride dependence of the alpha-amylase paralog amyrel in Drosophila melanogaster and Drosophila virilis species.

    Science.gov (United States)

    Claisse, Gaëlle; Feller, Georges; Bonneau, Magalie; Da Lage, Jean-Luc

    2016-08-01

    In animals, most α-amylases are chloride-dependent enzymes. A chloride ion is required for allosteric activation and is coordinated by one asparagine and two arginine side chains. Whereas the asparagine and one arginine are strictly conserved, the main chloride binding arginine is replaced by a glutamine in some rare instances, resulting in the loss of chloride binding and activation. Amyrel is a distant paralogue of α-amylase in Diptera, which was not characterized biochemically to date. Amyrel shows both substitutions depending on the species. In Drosophila melanogaster, an arginine is present in the sequence but in Drosophila virilis, a glutamine occurs at this position. We have investigated basic enzymological parameters and the dependence to chloride of Amyrel of both species, produced in yeast, and in mutants substituting arginine to glutamine or glutamine to arginine. We found that the amylolytic activity of Amyrel is about thirty times weaker than the classical Drosophila α-amylase, and that the substitution of the arginine by a glutamine in D. melanogaster suppressed the chloride-dependence but was detrimental to activity. In contrast, changing the glutamine into an arginine rendered D. virilis Amyrel chloride-dependent, and interestingly, significantly increased its catalytic efficiency. These results show that the chloride ion is not mandatory for Amyrel but stimulates the reaction rate. The possible phylogenetic origin of the arginine/glutamine substitution is also discussed. Copyright © 2016 Elsevier Ltd. All rights reserved.

  10. The study of interaction of modified fatty acid with {sup 99m}Tc in alcoholic media

    Energy Technology Data Exchange (ETDEWEB)

    Skuridin, V. S.; Stasyuk, E. S.; Varlamova, N. V.; Nesterov, E. A.; Sadkin, V. L.; Rogov, A. S., E-mail: rogov@tpu.ru; Ilina, E. A.; Larionova, L. A.; Villa, N. E. [Institute of Physics and Technology, Tomsk Polytechnic University, Tomsk, 634050 (Russian Federation); Sinilkin, I. G.; Zelchan, R. V. [Institute of Physics and Technology, Tomsk Polytechnic University, Tomsk, 634050 (Russian Federation); Tomsk Cancer Research Institute, Tomsk, 634050 (Russian Federation); Sazonova, S. I. [Institute of Physics and Technology, Tomsk Polytechnic University, Tomsk, 634050 (Russian Federation); Research Institute of Cardiology, Tomsk, 634012 (Russian Federation)

    2016-08-02

    The paper presents the results of laboratory research aimed at the development of methods of synthesis of new radiodiagnostic agents based on modified fatty acid labelled with technetium-99m intended for scintigraphic evaluation of myocardial metabolism. In particular, the interaction of substance with {sup 99m}Tc in alcoholic media and the use of ethanol as solvent in the synthesis of the radiopharmaceutical were studied.

  11. Chloride binding site of neurotransmitter sodium symporters

    DEFF Research Database (Denmark)

    Kantcheva, Adriana Krassimirova; Quick, Matthias; Shi, Lei

    2013-01-01

    Neurotransmitter:sodium symporters (NSSs) play a critical role in signaling by reuptake of neurotransmitters. Eukaryotic NSSs are chloride-dependent, whereas prokaryotic NSS homologs like LeuT are chloride-independent but contain an acidic residue (Glu290 in LeuT) at a site where eukaryotic NSSs...

  12. Extraction of trace thorium from hydrochloric acid media by 1-phenyl-3-methyl-4-benzoyl-5-pyrazolone

    Institute of Scientific and Technical Information of China (English)

    YANG Wei-Fan; YUAN Shuang-Gui; XU Yan-Bing; XIAO Yong-Hou; XIONG Bing

    2003-01-01

    The paper describes the solvent extraction of trace thorium from hydrochloric acid media by1-phenyl-3-methyl-4-benzoyl-5-pyrazolone (PMBP) using a radioactive tracer technique. The percent extraction ofthorium was studied as a function of acidity, PMBP concentration and equilibrium time. The back-extraction behaviorof thorium from the organic phase was also tested. Separation of thorium was performed from fission products pro-duced in 14 MeV neutron bombardment of natural uranium by employing the PMBP extraction procedure. Thegamma-ray spectra of the separated thorium fractions show that thorium can be separated from most of fission prod-ucts and a large amount of uranium.

  13. Separation of DR synthesized Ti-Mg Alloy by dissolution of waste by-products in acid media

    CSIR Research Space (South Africa)

    Mushove, T

    2010-06-01

    Full Text Available Of DR Synthesized Ti-Mg Alloy By Dissolution Of Waste By-Products In Acid Media. The dissolution experiments were done in a Julabo SW23 waterbath shaker, with 300 ml flasks. Acid solution of predetermined molarity was charged into a flask and heated... conditions as TiO2-Mg to:- ? investigate how they would behave in the leaching reagents reviewed. ? note how well the Ti-Mg separation process could be achieved by each reagent. Figure 2: Effect of H2SO4 concentration Figure 3: Effect of HCL...

  14. Comparative avoidance behaviour of the earthworm Eisenia fetida towards chloride, nitrate and sulphate salts of Cd, Cu and Zn using filter paper and extruded water agar gels as exposure media.

    Science.gov (United States)

    Demuynck, Sylvain; Lebel, Aurélie; Grumiaux, Fabien; Pernin, Céline; Leprêtre, Alain; Lemière, Sébastien

    2016-07-01

    We studied the avoidance behaviour of the earthworm Eisenia fetida towards Cd, Cu, and Zn, trace elements (TEs) tested as chloride, nitrate and sulphate salts. Sub adults were exposed individually using dual-cell chambers at 20+2°C in the dark. Recordings were realised at different dates from 2h to 32h. We used filter paper and extruded water agar gel as exposure media to evaluate the contribution of the dermal and the digestive exposure routes on the avoidance reactions. Exposures to Cu or Cd (10mgmetal ionL(-1)) resulted in highly significant avoidance reactions through the exposure duration. Worms avoided Zn poorly and reactions towards Zn salts varied along the exposure. Worm sensitivity towards TEs differed between salts and this could result from differential toxicity or accessibility of these TE salts to earthworms. The anion in itself was not the determinant of the avoidance reactions since exposures to similar concentrations of these anions using calcium salts did not result in significant avoidance worm behaviour. Avoidance responses towards TEs were higher in the case of water agar exposures than in filter paper exposures. Thus, dermal contacts with TE solutions would elicit worm avoidance but signals from receptors located inside the digestive tract could reinforce this behaviour. The use of extruded water agar gels as the substrate allows checking the real sensitivity of earthworm species towards TEs since the TE concentrations leading to significant avoidance reactions were below those reported in the literature when using TE-spiked soils.

  15. Pd-catalyzed ethylene methoxycarbonylation with Brønsted acid ionic liquids as promoter and phase-separable reaction media

    DEFF Research Database (Denmark)

    Garcia-Suarez, Eduardo J.; Khokarale, Santosh Govind; Nguyen van Buu, Olivier;

    2014-01-01

    Brønsted acid ionic liquids (BAILs) were prepared and applied as combined acid promoters and reaction media in Pd–phosphine catalyzed methoxycarbonylation of ethylene to produce methyl propionate. The BAILs served as alternatives to common mineral acids required for the reaction, e.g. methanesulf...

  16. Increased dietary sodium chloride concentrations reduce endogenous amino acid flow and influence the physiological response to the ingestion of phytic acid by broiler chickens.

    Science.gov (United States)

    Cowieson, A J; Bedford, M R; Ravindran, V; Selle, P H

    2011-10-01

    A total of 240 Ross 308 broilers were used to investigate the effect of sodium (1·5 or 2·5 g/kg), phytate-P (0 or 3·2 g/kg), and phytase (0 or 1000 FTU/kg; 2x2x2 factorial) on endogenous amino acid flow using the enzyme-hydrolysed casein method. The ingestion of phytate increased endogenous amino acid flow (∼30%) compared with the phytate-free control diets. Phytase reduced endogenous amino acid flow only when fed in concert with phytate, resulting in a significant phytate x phytase interaction. Increasing dietary sodium concentration from 1·5 to 2·5 g/kg reduced endogenous amino acid flow by around 10%. This reduction of endogenous flow was particularly evident in diets which contained phytate, resulting in a significant sodium x phytate interaction for several amino acids, including Thr and Ser. Further, high sodium concentrations muted the effect of phytase resulting in a significant sodium x phytase interaction for some amino acids. The concentration of Asp, Thr, Ser and some other amino acids was increased in the endogenous protein in response to the ingestion of phytate. Both sodium and phytase essentially restored the composition of endogenous protein to that of the phytate-free control. Further, as both sodium and phytase had similar effects there were significant interactions between sodium and phytase for most amino acids, such that one was only effective in the absence of the other. These data confirm previous reports that phytate is a nutritional aggressor, causing quantitative and qualitative changes in endogenous protein flow. However, this is the first report which has shown that dietary sodium concentrations play a role in the severity of this antinutritional effect and consequently may blunt the efficacy of exogenous phytase. The mechanism is obscure, though it has been previously demonstrated that sodium can disrupt phytate:protein complexes, thus mitigating one of the mechanisms by which phytate exerts its antinutritional effect.

  17. Chloride, gluconate, sulfate, and short-chain fatty acids affect calcium flux rates across the sheep forestomach epithelium.

    Science.gov (United States)

    Leonhard-Marek, S; Becker, G; Breves, G; Schröder, B

    2007-03-01

    In ruminants, more than 50% of overall gastrointestinal Ca absorption can occur preintestinally, and the anions of orally applied Ca salts are thought to play an important role in stimulating ruminal Ca absorption. This assumption is based mainly on ion-exchange studies that have used gluconate as the control anion, which may bind Ca2+ ions and interfere with treatment effects. In the present study, we investigated the distinct effects of different anions on Ca absorption across the sheep rumen and on the concentration of free Ca2+ ions ([Ca2+]ion). We showed that gluconate, sulfate, and short-chain fatty acids (SCFA) remarkably reduced [Ca2+]ion in buffer solutions. Nevertheless, increasing the Cl or SCFA concentration by 60 mM stimulated net ruminal Ca absorption 5- to 7-fold, but these effects could be antagonized by gluconate. Therefore, ion-exchange experiments must be (re)evaluated very carefully, because changes in [Ca2+]ion in the presence of gluconate, sulfate, or SCFA not only might entail an underestimation of Ca flux rates, but also might have effects on other cellular pathways that are Ca2+ dependent. Concerning the optimal Ca supply for dairy cows, the present study suggests that CaCl2 formulations and Ca salts of the SCFA stimulate Ca absorption across the rumen wall and are beneficial in preventing or correcting a Ca deficiency.

  18. Comparison Between the Inhibition Efficiencies of Two Modification Processes with PEG-Ceria Based Layers Against Corrosion of Mild Steel in Chloride and Sulfate Media

    Science.gov (United States)

    Boudellioua, H.; Hamlaoui, Y.; Tifouti, L.; Pedraza, F.

    2017-08-01

    Cerium (III) and polyethylene glycol (PEG) combinations were employed to enhance the corrosion resistance of ASTM A915 mild steel in 0.1 M NaCl and in 0.1 M Na2SO4 media. One of the combinations consisted in dipping the steel in a bath mixture of PEG and cerium nitrate for 60 min. In the second combination, the steel was first immersed in the PEG solution for 30 min, then in cerium nitrate for 30 additional minutes. The corrosion protective capabilities of the superficially modified steels were evaluated through cyclic voltammetry, linear polarization resistance (R p), polarization measurements (Tafel) and electrochemical impedance spectroscopy. The composition and structure of the surface products were analyzed through Raman spectroscopy and scanning electron microscopy coupled to chemical EDS analysis. The mixture of PEG and cerium nitrate hindered the development of corrosion products on the mild steel surface. However, the subsequent immersion of the steel first in PEG then in cerium nitrate was not efficient to slow down corrosion.

  19. Production of poly-gamma-glutamic acid by Bacillus subtilis and Bacillus licheniformis with different growth media.

    Science.gov (United States)

    Kedia, Gopal; Hill, David; Hill, Robert; Radecka, Iza

    2010-09-01

    Poly gamma-glutamic acid is a naturally occurring homo-polyamide that is made of D- and L-glutamic acid units connected by amide linkages between alpha-amino and gamma-carboxylic groups. Many strains have been studied for the production of poly y-glutamic acid, B. licheniformis 9945a and B. subtilis natto are the two most widely studied strains due to their higher yield. Both of these strains require L-glutamic acid for poly gamma-glutamic acid production. This paper describes investigations on the biosynthesis of poly y-glutamic acid by B. licheniformis 9945a and B. subtilis natto in an automated pH-controlled fermenter. The effect of the growth media such as medium E, F, C and GS was investigated. Medium E produced poly gamma-glutamic acid both with and without MnSO4 in the medium when fermented by B. licheniformis. Presence of MnSO4 in the medium affected both the yield and biomass production. The yield was 12 g/l for the medium containing 2.46 mM MnSO4 whereas it was only 4-5 g/l for the medium without MnSO4 with molecular weight (Mw) of 321,000. Different media such as medium C, F and GS were used for production of poly gamma-glutamic acid by B. subtilis natto. The yield from GS medium was highest and it produced about 26-28 g/l with molecular weight (Mw) of 627,000.

  20. Facilitated transport of titanium dioxide nanoparticles by humic substances in saturated porous media under acidic conditions

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Ruichang [Chinese Academy of Sciences, Key Laboratory of Soil Environment and Pollution Remediation, Institute of Soil Science (China); Zhang, Haibo; Tu, Chen; Hu, Xuefeng; Li, Lianzhen [Chinese Academy of Sciences, Key Laboratory of Coastal Environmental Processes and Ecological Remediation, Yantai Institute of Coastal Zone Research (China); Luo, Yongming, E-mail: ymluo@yic.ac.cn; Christie, Peter [Chinese Academy of Sciences, Key Laboratory of Soil Environment and Pollution Remediation, Institute of Soil Science (China)

    2015-04-15

    The transport behavior of titanium dioxide nanoparticles (TiO{sub 2} NPs, 30 nm in diameter) was studied in well-defined porous media composed of clean quartz sand over a range of solution chemistry under acidic conditions. Transport of TiO{sub 2} NPs was dramatically enhanced by humic substances (HS) at acidic pH (4.0, 5.0 and 6.0), even at a low HS concentration of 0.5 mg L{sup −1}. Facilitated transport of TiO{sub 2} NPs was likely attributable to the increased stability of TiO{sub 2} NPs and repulsive interaction between TiO{sub 2} NPs and quartz sands due to the adsorbed HS. The mobility of TiO{sub 2} NPs was also increased with increasing pH from 4.0 to 6.0. Although transport of TiO{sub 2} NPs was insensitive to low ionic strength, it was significantly inhibited by high concentrations of NaCl and CaCl{sub 2}. In addition, calculated Derjaguin–Landau–Verwey–Overbeek (DLVO) interaction energy indicated that high energy barriers were responsible for the high mobility of TiO{sub 2} NPs, while the secondary energy minimum could play an important role in the retention of TiO{sub 2} NPs at 100 mmol L{sup −1} NaCl. Straining and gravitational settlement of larger TiO{sub 2} NPs aggregates at 1 mg L{sup −1} HS, pH 5.0, and 2 mmol L{sup −1} CaCl{sub 2} could be responsible for the significant retention even in the presence of high energy barriers. Moreover, more favorable interaction between approaching TiO{sub 2} NPs and TiO{sub 2} NPs that had been already deposited on the collector resulted in a ripening-shape breakthrough curve at 2 mmol L{sup −1} CaCl{sub 2}. Overall, a combination of mechanisms including DLVO-type force, straining, and physical filtration was involved in the retention of TiO{sub 2} NPs over the range of solution chemistry examined in this study.

  1. Effect of ammonium sulfate, ammonium chloride and root-zone acidity on inorganic ion content of tobacco

    Science.gov (United States)

    Vessey, J. K.; Raper, C. D. Jr; Henry, L. T.; Raper CD, J. r. (Principal Investigator)

    1990-01-01

    Tobacco plants (Nicotiana tabacum L. cv NC82) were supplied with (NH4)2SO4 or NH4Cl at root-zone pH of 6.0 and 4.5 in hydroponic culture for 28 days. Dry matter accumulation, total N and C content, and leaf area and number were not affected by the NH4+ source or root-zone pH. Plants supplied with NH4Cl accumulated up to 1.2 mM Cl g DW-1, but accumulated 37% less inorganic H2PO4- and 47% less SO4(2-) than plants supplied with (NH4)2SO4. The large Cl- accumulation resulted in NH4Cl- supplied plants having a 31% higher inorganic anion (NO3-, H2, PO4-, SO4(2-), and Cl-) charge. This higher inorganic anion charge in the NH4Cl-supplied plants was balanced by a similar increase in K+ charge. Plants supplied with NH4Cl accumulated greater concentrations of Cl- in leaves (up to 5.1% of DW) than plants supplied with (NH4)2SO4 (less than -% DW). Despite the high Cl- concentration of leaves in NH4Cl supplied plants, these plants showed no symptoms of Cl- toxicity. This demonstrates that toxicity symptoms are not due solely to an interaction between high Cl- concentration in tissue and NH4+ nutrition. The increase in root-zone acidity to pH 4.5 from 6.0 did not induce toxicity symptoms.

  2. Kinetic analysis of strains of lactic acid bacteria and acetic acid bacteria in cocoa pulp simulation media toward development of a starter culture for cocoa bean fermentation.

    Science.gov (United States)

    Lefeber, Timothy; Janssens, Maarten; Camu, Nicholas; De Vuyst, Luc

    2010-12-01

    The composition of cocoa pulp simulation media (PSM) was optimized with species-specific strains of lactic acid bacteria (PSM-LAB) and acetic acid bacteria (PSM-AAB). Also, laboratory fermentations were carried out in PSM to investigate growth and metabolite production of strains of Lactobacillus plantarum and Lactobacillus fermentum and of Acetobacter pasteurianus isolated from Ghanaian cocoa bean heap fermentations, in view of the development of a defined starter culture. In a first step, a selection of strains was made out of a pool of strains of these LAB and AAB species, obtained from previous studies, based on their fermentation kinetics in PSM. Also, various concentrations of citric acid in the presence of glucose and/or fructose (PSM-LAB) and of lactic acid in the presence of ethanol (PSM-AAB) were tested. These data could explain the competitiveness of particular cocoa-specific strains, namely, L. plantarum 80 (homolactic and acid tolerant), L. fermentum 222 (heterolactic, citric acid fermenting, mannitol producing, and less acid tolerant), and A. pasteurianus 386B (ethanol and lactic acid oxidizing, acetic acid overoxidizing, acid tolerant, and moderately heat tolerant), during the natural cocoa bean fermentation process. For instance, it turned out that the capacity to use citric acid, which was exhibited by L. fermentum 222, is of the utmost importance. Also, the formation of mannitol was dependent not only on the LAB strain but also on environmental conditions. A mixture of L. plantarum 80, L. fermentum 222, and A. pasteurianus 386B can now be considered a mixed-strain starter culture for better controlled and more reliable cocoa bean fermentation processes.

  3. Formylation of Mandelic Acid Chloride to Cefamandole Nafate on the Influence of the Material%甲酰化扁桃酰氯对头孢孟多酯钠有关物质的影响

    Institute of Scientific and Technical Information of China (English)

    王军; 王金星; 侯善波; 张继文

    2013-01-01

    Objectiveensure the quality of formylation of mandelic acid chloride to cefamandole nafate on the influence of the material.Method:Choose diferent quality of formylation of mandelic acid chloride,with same synthetic process to get cefamandole nafate and HPLC related substance inspection.Result:the quality of formylation of mandelic acid chloride have a strong impact on cefamandole nafate single impurity content in related substance.%目的:确定甲酰化扁桃酰氯的质量对头孢孟多酯钠有关物质的影响。方法选择不同质量的甲酰化扁桃酰氯,用相同的合成工艺制的头孢孟多酯钠,对制的的头孢孟多酯钠进行HPLC的有关物质检查。结果甲酰化扁桃酰氯的质量严重影响头孢孟多酯钠的有关物质中的单杂含量。

  4. Hydrometallurgical process for the recovery of metal values from spent lithium-ion batteries in citric acid media.

    Science.gov (United States)

    Chen, Xiangping; Zhou, Tao

    2014-11-01

    In this paper, a hydrometallurgical process has been proposed to recover valuable metals from spent lithium-ion batteries in citric acid media. Leaching efficiencies as high as 97%, 95%, 94%, and 99% of Ni, Co, Mn, and Li were achieved under the optimal leaching experimental conditions of citric acid concentration of 2 mol L(-1), leaching temperature of 80 °C, leaching time of 90 min, liquid-solid ratio of 30 ml g(-1), and 2 vol. % H2O2. For the metals recovery process, nickel and cobalt were selectively precipitated by dimethylglyoxime reagent and ammonium oxalate sequentially. Then manganese was extracted by Na-D2EHPA and the manganese-loaded D2EHPA was stripped with sulfuric acid. The manganese was recovered as MnSO4 in aqueous phase and D2EHPA could be reused after saponification. Finally, lithium was precipitated by 0.5 mol L(-1) sodium phosphate. Under their optimal conditions, the recovery percentages of Ni, Co, Mn, and Li can reach 98%, 97%, 98%, and 89%, respectively. This is a relatively simple route in which all metal values could be effectively leached and recovered in citric acid media.

  5. An efficient protocol for incorporation of an unnatural amino acid in perdeuterated recombinant proteins using glucose-based media

    Energy Technology Data Exchange (ETDEWEB)

    Venditti, Vincenzo; Fawzi, Nicolas L.; Clore, G. Marius, E-mail: mariusc@mail.nih.gov [National Institutes of Health, Laboratory of Chemical Physics, National Institute of Diabetes and Digestive and Kidney Diseases (United States)

    2012-03-15

    The in vivo incorporation of unnatural amino acids into proteins is a well-established technique requiring an orthogonal tRNA/aminoacyl-tRNA synthetase pair specific for the unnatural amino acid that is incorporated at a position encoded by a TAG amber codon. Although this technology provides unique opportunities to engineer protein structures, poor protein yields are usually obtained in deuterated media, hampering its application in the protein NMR field. Here, we describe a novel protocol for incorporating unnatural amino acids into fully deuterated proteins using glucose-based media (which are relevant to the production, for example, of amino acid-specific methyl-labeled proteins used in the study of large molecular weight systems). The method consists of pre-induction of the pEVOL plasmid encoding the tRNA/aminoacyl-tRNA synthetase pair in a rich, H{sub 2}O-based medium prior to exchanging the culture into a D{sub 2}O-based medium. Our protocol results in high level of isotopic incorporation ({approx}95%) and retains the high expression level of the target protein observed in Luria-Bertani medium.

  6. Lubiprostone: a chloride channel activator.

    Science.gov (United States)

    Lacy, Brian E; Levy, L Campbell

    2007-04-01

    In January 2006 the Food and Drug Administration approved lubiprostone for the treatment of chronic constipation in men and women aged 18 and over. Lubiprostone is categorized as a prostone, a bicyclic fatty acid metabolite of prostaglandin E1. Lubiprostone activates a specific chloride channel (ClC-2) in the gastrointestinal (GI) tract to enhance intestinal fluid secretion, which increases GI transit and improves symptoms of constipation. This article reviews the role of chloride channels in the GI tract, describes the structure, function, and pharmacokinetics of lubiprostone, and discusses clinically important data on this new medication.

  7. Curcumin-cysteine and curcumin-tryptophan conjugate as fluorescence turn on sensors for picric Acid in aqueous media.

    Science.gov (United States)

    Gogoi, Bedanta; Sen Sarma, Neelotpal

    2015-06-03

    Rapid detection of picric acid in real sample is of outmost importance from the perspective of health, safety, and environment. In this study, a very simple and cost-effective detection of picric acid is accomplished by developing a couple of biobased conjugates curcumin-cysteine (CC) and curcumin-tryptophan (CT), which undergo efficient fluorescence turn on toward picric acid in aqueous media. Both the probes experience about 26.5-fold fluorescence enhancements at 70 nM concentration of the analyte. Here, the fluorescence turn on process is governed by the aggregation induced emission, which is induced from the electrostatic interaction between the conjugates with picric acid. The detection limit of CC and CT are about 13.51 and 13.54 nM of picric acid, respectively. Importantly, both the probes exhibit high selectivity and low interference of other analogues toward the detection of picric acid. In addition, the probes are highly photostable, show low response time and are practically applicable for sensing picric acid in real environmental samples, which is the ultimate goal of this work.

  8. Fundamental Mechanistic Understanding of Electrocatalysis of Oxygen Reduction on Pt and Non-Pt Surfaces: Acid versus Alkaline Media

    Directory of Open Access Journals (Sweden)

    Nagappan Ramaswamy

    2012-01-01

    Full Text Available Complex electrochemical reactions such as Oxygen Reduction Reaction (ORR involving multi-electron transfer is an electrocatalytic inner-sphere electron transfer process that exhibit strong dependence on the nature of the electrode surface. This criterion (along with required stability in acidic electrolytes has largely limited ORR catalysts to the platinum-based surfaces. New evidence in alkaline media, discussed here, throws light on the involvement of surface-independent outer-sphere electron transfer component in the overall electrocatalytic process. This surface non-specificity gives rise to the possibility of using a wide-range of non-noble metal surfaces as electrode materials for ORR in alkaline media. However, this outer-sphere process predominantly leads only to peroxide intermediate as the final product. The importance of promoting the electrocatalytic inner-sphere electron transfer by facilitation of direct adsorption of molecular oxygen on the active site is emphasized by using pyrolyzed metal porphyrins as electrocatalysts. A comparison of ORR reaction mechanisms between acidic and alkaline conditions is elucidated here. The primary advantage of performing ORR in alkaline media is found to be the enhanced activation of the peroxide intermediate on the active site that enables the complete four-electron transfer. ORR reaction schemes involving both outer- and inner-sphere electron transfer mechanisms are proposed.

  9. Fabrication of MCM-41 fibers with well-ordered hexagonal mesostructure controlled in acidic and alkaline media

    Science.gov (United States)

    Jafarzadeh, A.; Sohrabnezhad, Sh.; Zanjanchi, M. A.; Arvand, M.

    2016-10-01

    In this paper, synthesis and characterization of two type morphologies of the MCM-41mesoporous material, nano and microfibers, were investigated by electrospinning technique. The synthesis was performed in acidic and alkaline media, separately. The MCM-41 morphologies were characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), x-ray powder diffraction (XRD), and nitrogen adsorption-desorption measurement. Tetraethylorthosilicate (TEOS) and cetyltrimethylammonium bromide (CTAB) were used as silica and template sources for the synthesis of MCM-41 morphologies, respectively. The SEM results showed that MCM-41 nanofibers were spun in acidic media and microfibers of MCM-41 were produced in alkaline media. The XRD study revealed a long range structural ordering of mesoporous materials. The TEM results indicated rough surfaces with uniform average diameter 200 nm for nanofibers and 2 μm for microfibers. The pore diameter and surface area of calcined MCM-41 nanofibers were 2.2 nm and 970 m2/g, respectively. For the MCM-41 microfibers, pore sizes of 2.7 nm and surface areas 420 m2/g was measured.

  10. Application of Convective Interaction Media (CIM) disk monolithic columns for fast separation and monitoring of organic acids.

    Science.gov (United States)

    Vodopivec, M; Podgornik, A; Berovic, M; Strancar, A

    2000-11-01

    The separation of organic acids on the anion-exchange monolithic support, commercially available as Convective Interaction Media (CIM), is presented in this study. It is demonstrated that citric, isocitric, pyruvic, fumaric, malic, and alpha-ketoglutaric acid can be successfully separated using a CIM monolithic column of suitable user-adjustable length. The effect of the mobile phase composition on the separation is investigated. CIM monolithic columns of adjustable length from 3 to 18 mm are compared regarding the resolution and the back pressure. It is shown that the CIM monolithic column of 12 mm in length enables a good separation of all six organic acids within 3 min and exhibits a linear dependence of back pressure versus flow rate. The resolution and the dynamic binding capacity are found to be flow-unaffected. A filtrated sample of bioprocess supernatant is analyzed without previous pretreatment, which indicates the possibility of online monitoring of small molecules during the bioprocess using CIM monolithic columns.

  11. CRASH-2 Study of Tranexamic Acid to Treat Bleeding in Trauma Patients: A Controversy Fueled by Science and Social Media

    Directory of Open Access Journals (Sweden)

    Sophia Binz

    2015-01-01

    Full Text Available This paper reviews the application of tranexamic acid, an antifibrinolytic, to trauma. CRASH-2, a large randomized controlled trial, was the first to show a reduction in mortality and recommend tranexamic acid use in bleeding trauma patients. However, this paper was not without controversy. Its patient recruitment, methodology, and conductance in moderate-to-low income countries cast doubt on its ability to be applied to trauma protocols in countries with mature trauma networks. In addition to traditional vetting in scientific, peer-reviewed journals, CRASH-2 came about at a time when advances in communication technology allowed debate and influence to be leveraged in new forms, specifically through the use of multimedia campaigns, social media, and Internet blogs. This paper presents a comprehensive view of tranexamic acid utilization in trauma from peer-reviewed evidence to novel multimedia influences.

  12. CRASH-2 Study of Tranexamic Acid to Treat Bleeding in Trauma Patients: A Controversy Fueled by Science and Social Media.

    Science.gov (United States)

    Binz, Sophia; McCollester, Jonathon; Thomas, Scott; Miller, Joseph; Pohlman, Timothy; Waxman, Dan; Shariff, Faisal; Tracy, Rebecca; Walsh, Mark

    2015-01-01

    This paper reviews the application of tranexamic acid, an antifibrinolytic, to trauma. CRASH-2, a large randomized controlled trial, was the first to show a reduction in mortality and recommend tranexamic acid use in bleeding trauma patients. However, this paper was not without controversy. Its patient recruitment, methodology, and conductance in moderate-to-low income countries cast doubt on its ability to be applied to trauma protocols in countries with mature trauma networks. In addition to traditional vetting in scientific, peer-reviewed journals, CRASH-2 came about at a time when advances in communication technology allowed debate and influence to be leveraged in new forms, specifically through the use of multimedia campaigns, social media, and Internet blogs. This paper presents a comprehensive view of tranexamic acid utilization in trauma from peer-reviewed evidence to novel multimedia influences.

  13. Novel two-component gels of cetylpyridinium chloride and the bola-amphiphile 6-amino caproic acid: phase evolution and mechanism of gel formation.

    Science.gov (United States)

    Ramakanth, Illa; Patnaik, Archita

    2012-03-08

    A two-component gel resulting from the amphiphilic cationic surfactant cetylpyridinium chloride (CPC) in the presence of a structure-forming bola-amphiphilic additive 6-aminocaproic acid (6-ACA) was realized and investigated. At a critical 6 wt % of 1:1 CPC:6-ACA, the yellow colored gel resulted from a 3:1 v/v CHCl(3):H(2)O critical binary solvent composition. The mixed amphiphilic system formed a 1:1 complex with a binding constant ~0.83 × 10(4) M(-1). Phase evolution and mechanism of gelation in the mixed CPC:6-ACA system was unraveled upon investigating the gel microstructure, based on spectroscopic, microscopic, and small-angle X-ray scattering (SAXS) investigations. The gel assembled as a lamellar organization, maintaining a loosely interdigitated bilayer structure of CPC and 6-ACA molecules through predominant charge transfer, H-bonding, and hydrophobic and intercomplex interactions. The SAXS pattern indicated a semicrystalline form to be the stable phase with alternating crystalline and amorphous layers; a novel mode of gelation with a widely disparate semicrystalline form of the lamellar gel was thus indicated, where the lamellar structure was deduced from the interplanar spacings. A transition from low viscosity reverse micellar solution to a yellow rigid gel upon aging was thus comprehended. The mixed amphiphile in varying polarity organic solvents in the presence of water indicated the nonconducive nature of gelation in very highly polar solvents, methanol, and DMF or, in very low polarity solvents, such as, cyclohexane and carbon tetrachloride.

  14. Synergistic effect of steam and lactic acid against Escherichia coli O157:H7, Salmonella Typhimurium, and Listeria monocytogenes biofilms on polyvinyl chloride and stainless steel.

    Science.gov (United States)

    Ban, Ga-Hee; Park, Sang-Hyun; Kim, Sang-Oh; Ryu, Sangryeol; Kang, Dong-Hyun

    2012-07-01

    This study was designed to investigate the individual and combined effects of steam and lactic acid (LA) on the inactivation of biofilms formed by Escherichia coli O157:H7, Salmonella Typhimurium, and Listeria monocytogenes on polyvinyl chloride (PVC) and stainless steel. Six day old biofilms were developed on PVC and stainless steel coupons by using a mixture of three strains each of three foodborne pathogens at 25°C. After biofilm development, PVC and stainless steel coupons were treated with LA alone (immersed in 0.5% or 2% for 5s, 15s, and 30s), steam alone (on both sides for 5, 10, and 20s), and the combination of steam and LA. The numbers of biofilm cells of the three foodborne pathogens were significantly (p<0.05) reduced as the amount of LA and duration of steam exposure increased. There was a synergistic effect of steam and LA on the viability of biofilm cells of the three pathogens. For all biofilm cells of the three foodborne pathogens, reduction levels of individual treatments ranged from 0.11 to 2.12 log CFU/coupon. The combination treatment of steam and LA achieved an additional 0.2 to 2.11 log reduction compared to the sum of individual treatments. After a combined treatment of immersion in 2% LA for 15s or 30s followed by exposure to steam for 20s, biofilm cells of the three pathogens were reduced to below the detection limit (1.48 log). From the results of this study, bacterial populations of biofilms on PVC coupons did not receive the same thermal effect as on stainless steel coupons. Effectiveness of steam and LA may be attributed to the difference between Gram-negative and Gram-positive characteristics of the bacteria studied. The results of this study suggest that the combination of steam and LA has potential as a biofilm control intervention for food processing facilities.

  15. Estimation of the uncertainty associated with the results based on the validation of chromatographic analysis procedures: application to the determination of chlorides by high performance liquid chromatography and of fatty acids by high resolution gas chromatography.

    Science.gov (United States)

    Quintela, M; Báguena, J; Gotor, G; Blanco, M J; Broto, F

    2012-02-03

    This article presents a model to calculate the uncertainty associated with an analytical result based on the validation of the analysis procedure. This calculation model is proposed as an alternative to commonly used bottom-up and top-down methods. This proposal is very advantageous as the validation of the procedures and the estimation of the uncertainty of the measurement are part of the technical requirements needed in order to obtain the ISO 17025:2005 accreditation. This model has been applied to the determination of chloride by liquid chromatography in lixiviates and in the determination of palmitic acid and stearic acid by gas chromatography in magnesium stearate samples.

  16. Isolation of polyvinyl chloride degrading bacterial strains from ...

    African Journals Online (AJOL)

    Isolation of polyvinyl chloride degrading bacterial strains from environmental samples using enrichment culture technique. ... by their ability to release chloride from PVC polymer, increase their cell density in test media, carbon dioxide production and growth on the surface of PVC film in plate assay. ... Article Metrics.

  17. Salt hydrates for in situ water activity control have acid-base effects on enzymes in nonaqueous media.

    Science.gov (United States)

    Fontes, Nuno; Harper, Neil; Halling, Peter J; Barreiros, Susana

    2003-06-30

    Salt hydrates very frequently are utilized as in situ water activity buffers in reaction mixtures of enzymes in nonaqueous media. In addition to buffering water activity, there is evidence that salt hydrates also often affect initial rates in other ways. This has been generally overlooked or thought to be related to water transfer effects. Here we show that salt hydrates can have important acid-base effects on enzymes in nonaqueous media. We performed transesterification reactions in n-hexane and in supercritical ethane catalyzed by cross-linked crystals of subtilisin, differing in the method used to set a(W), and confirmed that the presence of salt hydrate pairs significantly affected the catalytic performance of the enzyme. However, in the presence of a solid-state acid-base buffer, salt hydrates had no effect on enzymatic activity. Direct evidence for the acid-base effects of salt hydrates was obtained by testing their effect on the protonation state of an organo-soluble H(+)/Na(+) indicator. The four salt hydrate pairs tested affected the indicator to very different extents. By promoting the exchange of H(+) for Na(+), salt hydrates will tend to affect the ionization state of acidic residues in the protein and, hence, enzymatic activity. In fact, salt hydrates were able to affect the pH memory of subtilisin lyophilized from different aqueous pHs, bringing about up to 20-fold enhancements and up to 5-fold decreases in catalytic activity. The possibility of such acid-base effects need to be considered in all experiments using salt hydrates to control water activity.

  18. Adsorption and corrosion-inhibiting effect of Dacryodis edulis extract on low-carbon-steel corrosion in acidic media.

    Science.gov (United States)

    Oguzie, E E; Enenebeaku, C K; Akalezi, C O; Okoro, S C; Ayuk, A A; Ejike, E N

    2010-09-01

    The inhibition of low-carbon-steel corrosion in 1M HCl and 0.5M H(2)SO(4) by extracts of Dacryodis edulis (DE) was investigated using gravimetric and electrochemical techniques. DE extract was found to inhibit the uniform and localized corrosion of carbon steel in the acidic media, affecting both the cathodic and anodic partial reactions. The corrosion process was inhibited by adsorption of the extracted organic matter onto the steel surface in a concentration-dependent manner and involved both protonated and molecular species. Molecular dynamics simulations were performed to illustrate the process of adsorption of some specific components of the extract.

  19. Determination of the unusual amino acid hypusine at the lower picomole level by derivatization with 4-dimethylaminoazobenzene-4'-sulphonyl chloride and reversed-phase high-performance or medium-pressure liquid chromatography.

    Science.gov (United States)

    Bartig, D; Klink, F

    1992-07-31

    Hypusine, an unusual amino acid formed by post-translational modification of lysine, is normally determined by specific metabolic labelling followed by measurement of released radioactivity after protein hydrolysis. This paper describes a sensitive non-radioactive method for the determination of hypusine, involving complete protein hydrolysis and precolumn derivatization of the released amino acids with 4-dimethylaminoazobenzene-4'-sulphonyl chloride, followed by reversed-phase high-performance or medium-pressure liquid chromatography of the dabsylated derivatives. The detection limit of hypusine was about 500 fmol. Additionally, the hypusine-containing protein from the archaebacterium Sulfolobus acidocaldarius was purified. By applying the dabsylation method to the analysis of tryptic peptides derived from this protein, it was possible to determine the correct positioning of the hypusine residue in the amino acid sequence, which was not possible by the amino acid sequencing procedure alone.

  20. The Effect of Temperature and Acid Concentration on Corrosion of Low Carbon Steel in Hydrochloric Acid Media

    Directory of Open Access Journals (Sweden)

    Anees A. Khadom

    2009-01-01

    Full Text Available Problem statement: The effect of different temperatures and acid concentrations on the corrosion of low carbon steel in hydrochloric acid were addressed in this study. Approach: The effect of temperature was explained by application of Arrhenius equation and transition state theory, while the acid concentration effect was explained using reaction kinetic equations. The combined effect of temperature and acid concentration then modeled using a nonlinear regression method. Results: A detail of thermodynamic parameters of activation (E, ΔH* and ΔS* and kinetic studies for the corrosion reaction were obtained. Nonlinear corrosion rates as a function of temperature and acid concentration equation were estimated with a good prediction corrosion rates values. Conclusion: The values of activation energy E and enthalpy of activation ΔH* decrease with increase in acid concentration indicating the increasing in reaction rate. Entropy of activation ΔS* tend to lower values with increasing in acid concentration which indicated that the activated complex was more orderly relative to the initial state. The corrosion reaction was approximately firs order reaction. The observed corrosion rate values from the experimental data were in a good agreement with that predicated by the mathematical equation.

  1. Chloride on the Move

    KAUST Repository

    Li, Bo

    2017-01-09

    Chloride (Cl−) is an essential plant nutrient but under saline conditions it can accumulate to toxic levels in leaves; limiting this accumulation improves the salt tolerance of some crops. The rate-limiting step for this process – the transfer of Cl− from root symplast to xylem apoplast, which can antagonize delivery of the macronutrient nitrate (NO3−) to shoots – is regulated by abscisic acid (ABA) and is multigenic. Until recently the molecular mechanisms underpinning this salt-tolerance trait were poorly defined. We discuss here how recent advances highlight the role of newly identified transport proteins, some that directly transfer Cl− into the xylem, and others that act on endomembranes in ‘gatekeeper’ cell types in the root stele to control root-to-shoot delivery of Cl−.

  2. Optimization of media composition for D-amino acid oxidase production by Trigonopsis variabilis using biostatistical analysis.

    Science.gov (United States)

    Gupta, Neeraj; Gundampati, Ravi Kumar; Debnath, M

    2012-08-01

    D-amino acid oxidase (DAAO) is biotechnologically relevant enzyme that is used in various food and pharmaceutical industries. DAAO from the yeast Trigonopsis variabilis is an important agent for use in commercial applications because of its high activity with cephalosporin C and is reasonable resistant to the oxidants O2 and H2O2 byproducts of reaction. In this study, response surface methodology (RSM) in shake flask culture was used to enhance the production of DAAO from T. variabilis by optimization of fermentation media composition. The effects of six factors (DL-alanine, glucose, pH, ZnSO4, (NH4)2SO4 and temperature) were evaluated on DAAO production. Results of Placket-Burman design showed that DL-alanine, pH, glucose and ZnSO4 were significant factors for DAAO production (P<0.05). The optimum values of media components as predicted by the central composite design were inducer (DL-alanine) concentration 3 g/L, pH 7.7, glucose 17 g/L and ZnSO4 34 mg/L. At these optimum values of media composition, maximum production of DAAO was 153 U/g yeast dry weight. Two-fold increase in DAAO production was achieved after optimization of the physical parameters by RSM.

  3. Selective liquid-liquid extraction of antimony(III from hydrochloric acid media by N-n-octylaniline in xylene

    Directory of Open Access Journals (Sweden)

    M. A. ANUSE

    2004-04-01

    Full Text Available N-n-Octylaniline in xylene was used for the extraction separation of antimony(III from hydrochloric acid media. Antimony(III was extracted quantitatively with 10 mL 4 % N-n-octylaniline in xylene. It was stripped from the organic phase with 0.5 M ammonia and estimated photometrically by the iodide method. The effect of metal ion, acid, reagent concentration and various foreign ions was investigated. The method affords binary and ternary separation of antimony(III from tellurium(IV, selenium(IV, lead(II, bismuth(III, tin(IV, germanium(IV, copper(II, gold(III, iron(III and zinc(II. The method is applicable for the analysis of synthetic mixtures, alloys and semiconductor thin films. It is fast, accurate and precise.

  4. Protective effects of gastrodia elata on aluminium-chloride-induced learning impairments and alterations of amino acid neurotransmitter release in adult rats

    Science.gov (United States)

    Shuchang, He; Qiao, Niu; Piye, Niu; Mingwei, He; Xiaoshu, Sun; Feng, Shao; Sheng, Wang; Opler, Mark

    2009-01-01

    Purpose High brain levels of aluminum (Al) can be neurotoxic and cause learning and memory deficits. Gastrodia elata (GE) is a Chinese herb widely used for improving mental function in traditional Chinese medicine. We measured changes in Al-induced neurotransmitter alteration and performance on a learning and memory task to elucidate the mechanism of Al toxicity and to assess whether these alterations could be attenuated by GE. Methods Thirty-six adult, male rats were randomly divided into six groups. Four Al-exposed groups were given aluminum chloride at 5 mg/kg/day or 10 mg/kg/day (i.p.) for two months, with two of these groups (one for each dose of Al) receiving GE (0.4 g/kg, via oral intubation, with the GE powder mixed in the drinking water) while the other two groups received vehicle. A GE control group was given injections of saline plus GE and a saline control group was given injections of saline and with 3 injection days and one day off. A step-down test was used to measure learning and memory ability. Al concentrations in the neocortex were assayed with a graphite furnace atomic absorption spectrophotometer. Amino acid neurotransmitter levels in the neocortex were determined by high performance liquid chromatogram-fluorescence. Results Al-exposed rats showed impaired learning and memory ability as indicated by shorter step down latency and more retention errors. Cortical concentrations (mean ± SEM) of Al were: 56.22 ± 34.10 ng/g (wet weight) in the Saline control group; 172.87 ± 111.06 in the 5 mg/kg/dayAl group; 289.15 ± 102.55 in the 10mg Al group; 74.98 ± 19.00 in the GE control group; 232.55 ± 35.74 in 5 mg Al+GE group; and 291.35 ± 98.38 in 10 mg Al+GE group respectively. Al exposure produced a significant increase in cortical GABA levels. Gastrodia elata reduced learning and memory deficits without affecting brain Al levels. Conclusions Rats exposed to AlCl3 suffer from deficits in learning and memory, accompanied by increases in GABA levels

  5. Fixed bed sorption of phosphorus from wastewater using iron oxide-based media derived from acid mine drainage

    Science.gov (United States)

    Sibrell, Philip L.; Tucker, T.W.

    2012-01-01

    Phosphorus (P) releases to the environment have been implicated in the eutrophication of important water bodies worldwide. Current technology for the removal of P from wastewaters consists of treatment with aluminum (Al) or iron (Fe) salts, but is expensive. The neutralization of acid mine drainage (AMD) generates sludge rich in Fe and Al oxides that has hitherto been considered a waste product, but these sludges could serve as an economical adsorption media for the removal of P from wastewaters. Therefore, we have evaluated an AMD-derived media as a sorbent for P in fixed bed sorption systems. The homogenous surface diffusion model (HSDM) was used to analyze fixed bed test data and to determine the value of related sorption parameters. The surface diffusion modulus Ed was found to be a useful predictor of sorption kinetics. Values of Ed < 0.2 were associated with early breakthrough of P, while more desirable S-shaped breakthrough curves resulted when 0.2 < Ed < 0.5. Computer simulations of the fixed bed process with the HSDM confirmed that if Ed was known, the shape of the breakthrough curve could be calculated. The surface diffusion coefficient D s was a critical factor in the calculation of Ed and could be estimated based on the sorption test conditions such as media characteristics, and influent flow rate and concentration. Optimal test results were obtained with a relatively small media particle size (average particle radius 0.028 cm) and resulted in 96 % removal of P from the influent over 46 days of continuous operation. These results indicate that fixed bed sorption of P would be a feasible option for the utilization of AMD residues, thus helping to decrease AMD treatment costs while at the same time ameliorating the impacts of P contamination.

  6. Effects of media and indole butyric acid (IBA concentrations on hopbush (Dodoneae viscosa L. cuttings in green house

    Directory of Open Access Journals (Sweden)

    Vahid Reza Saffari

    2012-05-01

    Full Text Available Hopbush (Dodoneae viscosa L. is an evergreen bush type tree;that is used for hedges and green walls in parks, gardens and houses, in South East of Iran. Propagation by stem cuttings is quicker and cheaper than seed, if the cuttings set in convenient media and rooting hormone. In order to investigate the effects of different media and different concentrations of indole 3-butyric acid (IBA on rooting of hopbush (Dodonea viscosa L. cuttings, an experiment was conducted using mist system in greenhouse in spring 2010. The treatments were 3 different media: sand, perlite, and sand + perlite, (1+1 by volume, with 4 levels of IBA concentrations (0 ppm, 2000 ppm, 4000 ppm, and 6000 ppm. A randomized complete block with factorial design was used with 5 replications. The average and the means were compared by Duncun’s multiple range test (1% and 5%; M STAT-C was used for comparing the interaction effects. The effect of medium on number of roots, percentage survival of stem cutting, root fresh weight and dry weight was significant, but on root length was not significantly affected. The effects of different concentrations of hormoneon number of roots, percentage survival of stem cutting, root fresh weight and dry weight was significant. The interaction effect of media and hormone on root length was significant, too. The best result was obtained in perlite, with 4000 ppm IBA. The results showed that perlite medium and 4000 ppm IBA concentration can be suggested for soft wood cutting of hopbush.

  7. [Investigation of viral nucleic acids in middle-ear effusion specimens from children with acute otitis media].

    Science.gov (United States)

    Abu Sitteh, Muhammed H; Sener, Kenan; Yapar, Mehmet; Kiliç, Abdullah; Güney, Cakir; Kubar, Ayhan

    2008-07-01

    Acute otitis media with effusion (OME) is one of the major causes of antibiotic use, indication for operation and hearing loss in children. In two third of the cases the etiologic agents are bacteria. Nonetheless, increasing numbers of reports have implicated viruses as etiologic agents that may have some effect on prognosis of OME. The aim of this study was to investigate the presence of nucleic acids of respiratory syncytial virus (RSV) type A and B, influenza type A virus, adenovirus, cytomegalovirus (CMV), herpes simplex virus type-1 (HSV-1), and enteroviruses in the middle ear effusion specimens from children with otitis media by TaqMan real-time PCR. As a result, 18 of 30 (60%) OME samples were found positive in terms of viral nucleic acids by real-time PCR. RSV-A was detected in nine samples (30%), CMV in 3 (10%) samples and HSV-1 in 1 (3.3%) sample. In five of the samples two viruses were detected in the same sample (three were positive for adenovirus and RSV-A, and two were positive for CMV and RSV-A). Our data have supported the importance of viruses as etiologic agents of OME. Additionally, it was thought that TaqMan real-time PCR may be used as a reliable and rapid method for the detection of viruses in the middle ear effusion samples.

  8. Synthesis of ascorbyl oleate by transesterification of olive oil with ascorbic acid in polar organic media catalyzed by immobilized lipases.

    Science.gov (United States)

    Moreno-Perez, Sonia; Filice, Marco; Guisan, Jose M; Fernandez-Lorente, Gloria

    2013-09-01

    The reaction of transesterification between oils (e.g., olive oil) and ascorbic acid in polar anhydrous media (e.g., tert-amyl alcohol) catalyzed by immobilized lipases for the preparation of natural liposoluble antioxidants (e.g., ascorbyl oleate) was studied. Three commercial lipases were tested: Candida antarctica B lipase (CALB), Thermomyces lanuginosus lipase (TLL) and Rhizomucor miehei lipase (RML). Each lipase was immobilized by three different protocols: hydrophobic adsorption, anionic exchange and multipoint covalent attachment. The highest synthetic yields were obtained with CALB adsorbed on hydrophobic supports (e.g., the commercial derivative Novozym 435). The rates and yields of the synthesis of ascorbyl oleate were higher when using the solvent dried with molecular sieves, at high temperatures (e.g. 45°C) and with a small excess of oil (2 mol of oil per mol of ascorbic acid). The coating of CALB derivatives with polyethyleneimine (PEI) improved its catalytic behavior and allowed the achievement of yields of up to 80% of ascorbyl oleate in less than 24h. CALB adsorbed on a hydrophobic support and coated with PEI was 2-fold more stable than a non-coated derivative and one hundred-fold more stable than the best TLL derivative. The best CALB derivative exhibited a half-life of 3 days at 75°C in fully anhydrous media, and this derivative maintained full activity after 28 days at 45°C in dried tert-amyl alcohol.

  9. Inhibition of corrosion of mild steel in acid media by N′-benzylidene-3-(quinolin-4-ylthio)propanohydrazide

    Indian Academy of Sciences (India)

    V Ramesh Saliyan; Airody Vasudeva Adhikari

    2008-08-01

    In the present investigation a new corrosion inhibitor, N′-(3,4-dihydroxybenzylidene)-3-{[8-(trifluoromethyl) quinolin-4-yl]thio}propanohydrazide(DHBTPH) was synthesized, characterized and tested as a corrosion inhibitor for mild steel in HCl (1 M, 2 M) and H2SO4 (0.5 M, 1 M) solutions using weight-loss method, electrochemical impedance spectroscopy (EIS) and potentiodynamic polarization methods. The corrosion inhibition efficiency measured by all the above three techniques were in good agreement with each other. The results showed that DHBTPH is a very good inhibitor for mild steel in acidic media. The inhibition efficiency in different acid media was found to be in the decreasing order 0.5 M H2SO4 > 1 M HCl > 1 M H2SO4 > 2 M HCl. The inhibition efficiency increases with increasing inhibitor concentration and with increasing temperature. It acts as an anodic inhibitor. Thermodynamic and activation parameters are discussed. Adsorption of DHBTPH was found to follow the Langmuir’s adsorption isotherm. Chemisorption mechanism is proposed. The mild steel samples were also analysed by scanning electron microscopy (SEM).

  10. Dekkera and Brettanomyces growth and utilisation of hydroxycinnamic acids in synthetic media.

    Science.gov (United States)

    Harris, Victoria; Ford, Christopher M; Jiranek, Vladimir; Grbin, Paul R

    2008-04-01

    Dekkera and Brettanomyces yeast are important spoilage organisms in a number of food and beverage products. Isolates of both genera were cultured in a defined medium and supplemented with hydroxycinnamic acids and vinylphenols to investigate their influence on growth and the formation of ethyl phenol derivatives. The growth rate of Brettanomyces species in the presence of acids was reduced, and no significant conversion to vinyl or ethyl derivatives was observed. The growth rate and substrate utilisation rates of Dekkera anomala and Dekkera bruxellensis yeast differed depending on strain and the acid precursor present. Growth of D. bruxellensis was slowed by the presence of ferulic acid with the addition of 1 mM ferulic acid completely inhibiting growth. This study provides an insight into the spoilage potential of these organisms and possible control strategies involving hydroxycinnamic acids.

  11. The tetramethylammonium chloride method for screening of cDNA libraries using highly degenerate oligonucleotides obtained by backtranslation of amino-acid sequences

    DEFF Research Database (Denmark)

    Honoré, B; Madsen, Peder; Leffers, H

    1993-01-01

    We describe a method for screening of cDNA libraries with highly degenerate oligonucleotides using tetramethylammonium chloride (TMAC). This method is a convenient alternative to using probes generated by the polymerase chain reaction (PCR), especially when these cannot easily be made. Nylon filt...

  12. Solvent extraction of rare earth ions from nitrate media with new extractant di-(2,3-dimethylbutyl)-phosphinic acid

    Institute of Scientific and Technical Information of China (English)

    王俊莲; 陈广; 徐盛明; 尹祉力; 张覃

    2016-01-01

    As a relatively new extractant, di-(2,3-dimethylbutyl)-phosphinic acid (HYY-2) is more efficient to separate heavy rare earths Tm/Yb/Lu than Cyanex 272 and P507. In this paper, HYY-2 was synthesized in our lab, and the extraction equilibrium, ther-modynamics and stripping acidity for La, Gd and Y, which stood for light rare earth elements (REE), middle REE and heavy REE respectively, from nitrate media with this extractant were investigated. Meanwhile, extraction ability, capacity and stripping acidity of HYY-2 were investigated and compared with those of Cyanex 272 and P507. The separation performance for rare earth element cou-ples Gd/Eu and Er/Ywere also studied. Compared to Cyanex 272, it possessed higher extraction capacity; while compared with P507, it has lower stripping acidity. The maximumβGd/Eu 1.46 occurred at pHequilibrium=2.78 and the maximumβEr/Y was 1.47 when pHequilibrium= 2.01.

  13. Determination of amino acids in cell culture and fermentation broth media using anion-exchange chromatography with integrated pulsed amperometric detection.

    Science.gov (United States)

    Hanko, Valoran P; Rohrer, Jeffrey S

    2004-01-01

    Cell culture and fermentation broth media are used in the manufacture of biotherapeutics and many other biological materials. Characterizing the amino acid composition in cell culture and fermentation broth media is important because deficiencies in these nutrients can reduce desired yields or alter final product quality. Anion-exchange (AE) chromatography using sodium hydroxide (NaOH) and sodium acetate gradients, coupled with integrated pulsed amperometric detection (IPAD), determines amino acids without sample derivatization. AE-IPAD also detects carbohydrates, glycols, and sugar alcohols. The presence of these compounds, often at high concentrations in cell culture and fermentation broth media, can complicate amino acid determinations. To determine whether these samples can be analyzed without sample preparation, we studied the effects of altering and extending the initial NaOH eluent concentration on the retention of 42 different carbohydrates and related compounds, 30 amino acids and related compounds, and 3 additional compounds. We found that carbohydrate retention is impacted in a manner different from that of amino acid retention by a change in [NaOH]. We used this selectivity difference to design amino acid determinations of diluted cell culture and fermentation broth media, including Bacto yeast extract-peptone-dextrose (yeast culture medium) broth, Luria-Bertani (bacterial culture medium) broth, and minimal essential medium and serum-free protein-free hybridoma medium (mammalian cell culture media). These media were selected as representatives for both prokaryotic and eukaryotic culture systems capable of challenging the analytical technique presented in this paper. Glucose up to 10mM (0.2%, w/w) did not interfere with the chromatography, or decrease recovery greater than 20%, for the common amino acids arginine, lysine, alanine, threonine, glycine, valine, serine, proline, isoleucine, leucine, methionine, histidine, phenylalanine, glutamate, aspartate

  14. Effect of realgar on extracellular amino acid neurotransmitters in hippocampal CA1 region determined by online microdialysis–dansyl chloride derivatization–high-performance liquid chromatography and fluorescence detection.

    Science.gov (United States)

    Huo, Taoguang; Zhang, Yinghua; Li, Weikai; Yang, Huilei; Jiang, Hong; Sun, Guifan

    2014-09-01

    An online microdialysis (MD)–dansyl chloride (Dns) derivatization–high-performance liquid chromatography (HPLC) and fluorescence detection (FD) system was developed for simultaneous determination of eight extracellular amino acid neurotransmitters in hippocampus. The MD probe was implanted in hippocampal CA1 region. Dialysate and Dns were online mixed and derivatized. The derivatives were separated on an ODS column and detected by FD. The developed online system showed good linearity, precision, accuracy and recovery. This online MD-HPLC system was applied to monitor amino acid neurotransmitters levels in rats exposed to realgar (0.3, 0.9 and 2.7 g/kg body weight). The result shows that glutamate concentrations were significantly increased (pHPLC–FD system provides a new experimental method for studying the effect of toxic Chinese medicines on amino acid neurotransmitters.

  15. Functional modulation of cerebral gamma-aminobutyric acidA receptor/benzodiazepine receptor/chloride ion channel complex with ethyl beta-carboline-3-carboxylate: Presence of independent binding site for ethyl beta-carboline-3-carboxylate

    Energy Technology Data Exchange (ETDEWEB)

    Taguchi, J.; Kuriyama, K. (Kyoto Prefectural Univ. of Medicine (Japan))

    1990-05-01

    Effect of ethyl beta-carboline-3-carboxylate (beta-CCE) on the function of gamma-aminobutyric acid (GABA)A receptor/benzodiazepine receptor/chloride ion channel complex was studied. Beta-CCE noncompetitively and competitively inhibited (3H)flunitrazepam binding to benzodiazepine receptor, but not (3H)muscimol binding to GABAA receptor as well as t-(3H)butylbicycloorthobenzoate (( 3H) TBOB) binding to chloride ion channel, in particulate fraction of the mouse brain. Ro15-1788 also inhibited competitively (3H) flunitrazepam binding. On the other hand, the binding of beta-(3H)CCE was inhibited noncompetitively and competitively by clonazepam and competitively by Ro15-1788. In agreement with these results, benzodiazepines-stimulated (3H)muscimol binding was antagonized by beta-CCE and Ro15-1788. Gel column chromatography for the solubilized fraction from cerebral particulate fraction by 0.2% sodium deoxycholate (DOC-Na) in the presence of 1 M KCl indicated that beta-(3H)CCE binding site was eluted in the same fraction (molecular weight, 250,000) as the binding sites for (3H)flunitrazepam, (3H)muscimol and (3H)TBOB. GABA-stimulated 36Cl- influx into membrane vesicles prepared from the bovine cerebral cortex was stimulated and attenuated by flunitrazepam and beta-CCE, respectively. These effects of flunitrazepam and beta-CCE on the GABA-stimulated 36Cl- influx were antagonized by Ro15-1788. The present results suggest that the binding site for beta-CCE, which resides on GABAA receptor/benzodiazepine receptor/chloride ion channel complex, may be different from that for benzodiazepine. Possible roles of beta-CCE binding site in the allosteric inhibitions on benzodiazepine binding site as well as on the functional coupling between chloride ion channel and GABAA receptor are also suggested.

  16. Synthesis of bis(indolyl) methanes using aluminiumoxide(acidic) in dry media

    Institute of Scientific and Technical Information of China (English)

    Sandip; A.Sadaphal; Amol; H.Kategaonkar; Vilas; B.Labade; Murlidhar; S.Shingare

    2010-01-01

    Heterogeneous catalyst aluminium oxide(acidic) is found to be an effective catalyst for the solvent-free condensation reaction of indole with aldehydes in microwave irradiation with shorter reaction time and higher yields.

  17. Dissolution properties of co-amorphous drug-amino acid formulations in buffer and biorelevant media

    DEFF Research Database (Denmark)

    Heikkinen, A. T.; DeClerck, L.; Löbmann, Korbinian;

    2015-01-01

    -amorphous formulations have been tested only in buffers and their supersaturation ability remain unexplored. Consequently, dissolution studies in simulated intestinal fluids need to be conducted in order to better evaluate the potential of these systems in increasing the oral bioavailability of biopharmaceutics...... classification system class II drugs. In this study, solubility and dissolution properties of the co-amorphous simvastatin-lysine, gibenclamideserine, glibenclamide-threonine and glibenclamide-serine-threonine were studied in phosphate buffer pH 7.2 and biorelevant media (fasted and fed state simulated...

  18. Electrochemical impedance spectroscopy study on corrosion inhibition of benzyltriethylammonium chloride

    Science.gov (United States)

    Idris, Mohd Nazri; Daud, Abdul Razak; Othman, Norinsan Kamil

    2013-11-01

    Electrochemical Impedance Spectroscopy (EIS) was employed to study the corrosion inhibition behavior of benzyltriethylammonium chloride (BTC) for carbon steel corrosion. The inhibition efficiency was investigated in 1.0 M HCl solution at room temperature (25°C) by varying the BTC concentration. EIS results indicated that the double layer capacitance of electrolyte/carbon steel interface decreases with the increasing of BTC concentration and consequently enhances the polarization resistance of equivalence Randles circuit. The results indicated that inhibition efficiency of as high as 65% could be achieved when 10mM BTC was present in 1.0 M HCl solution as compared to inhibitor-free solution. The inhibition process of BTC on the carbon steel corrosion was found to obey Langmuir adsorption isotherm. This study revealed that BTC is suitable to be used as a corrosion inhibitor in acid media.

  19. Influence of gelatine on corrosion behavior of copper in acidic media

    OpenAIRE

    Todorović Dragiša A.; Milenković Dragan D.; Milosavljević Milutin M.; Marković Dragan A.

    2012-01-01

    This paper presents the results of gelatin and benzotriazole (BTA) inhibitory action on copper in the acid medium by the method of weight loss. The investigation was carried out in the citric acid solution (1, 5 and 20%) at the temperature of 293 K. Under such conditions, the gelatin showed higher efficiency of corrosion protection in comparison to BTA. The results, obtained through the Gibbs and Langmuir adsorption isotherm, show that gelatin adsorption on copper surface obey the Langm...

  20. Formic acid as an alternative reducing agent for the catalytic nitrate reduction in aqueous media.

    Science.gov (United States)

    Choi, Eun-Kyoung; Park, Kuy-Hyun; Lee, Ho-Bin; Cho, Misun; Ahn, Samyoung

    2013-08-01

    Formic acid was used for the nitrate reduction as a reductant in the presence of Pd:Cu/gamma-alumina catalysts. The surface characteristics of the bimetallic catalyst synthesized by wet impregnation were investigated by SEM, TEM-EDS. The metals were not distributed homogeneously on the surface of catalyst, although the total contents of both metals in particles agreed well with the theoretical values. Formic acid decomposition on the catalyst surface, its influence on solution pH and nitrate removal efficacy was investigated. The best removal of nitrate (50 ppm) was obtained under the condition of 0.75 g/L catalyst with Pd:Cu ratio (4:1) and two fold excess of formic acid. Formic acid decay patterns resembled those of nitrate removal, showing a linear relationship between k(f) (formic acid decay) and k (nitrate removal). Negligible amount of ammonia was detected, and no nitrite was detected, possibly due to buffering effect of bicarbonate that is in situ produced by the decomposition of formic acid, and due to the sustained release of H2 gas.

  1. Formic acid as an alternative reducing agent for the catalytic nitrate reduction in aqueous media

    Institute of Scientific and Technical Information of China (English)

    Eun-kyoung Choi; Kuy-hyun Park; Ho-bin Lee; Misun Cho; Samyoung Ahn

    2013-01-01

    Formic acid was used for the nitrate reduction as a reductant in the presence of Pd∶Cu/γ-alumina catalysts.The surfatce characteristics of the bimetallic catalyst synthesized by wet impregnation were investigated by SEM,TEM-EDS.The metals were not distributed homogeneously on the surface of catalyst,although the total contents of both metals in particles agreed well with the theoretical values.Formic acid decomposition on the catalyst surface,its influence on solution pH and nitrate removal efficacy was investigated.The best removal of nitrate (50 ppm) was obtained under the condition of 0.75 g/L catalyst with Pd∶Cu ratio (4∶1) and two fold excess of formic acid.Formic acid decay patterns resembled those of nitrate removal,showing a linear relationship between kf (formic acid decay) and k (nitrate removal).Negligible amount of ammonia was detected,and no nitrite was detected,possibly due to buffering effect of bicarbonate that is in situ produced by the decomposition of formic acid,and due to the sustained release of H2 gas.

  2. From unsuccessful H2-activation with FLPs containing B(Ohfip)3 to a systematic evaluation of the Lewis acidity of 33 Lewis acids based on fluoride, chloride, hydride and methyl ion affinities.

    Science.gov (United States)

    Böhrer, Hannes; Trapp, Nils; Himmel, Daniel; Schleep, Mario; Krossing, Ingo

    2015-04-28

    The possibility of obtaining frustrated Lewis pairs (FLPs) suitable for H2-activation based on the Lewis acid B(Ohfip)3 1 (Ohfip = OC(H)(CF3)2) was investigated. In this context, the crystal structure of 1 as well as the crystal structure of the very weak adduct 1·NCMe was determined. When reacting solutions of 1 with H2 (1 bar) and selected phosphanes, amines, pyridines and N-heterocyclic carbenes, dihydrogen activation was never observed. Without H2, adduct formation with 1 was observed to be an equilibrium process, regardless of the Lewis base adduct. Thus, the thermodynamics of H2 activation of 1 in comparison with the well-known B(C6F5)3 was analyzed using DFT calculations in the gas phase and different solvents (CH2Cl2, ortho-difluorobenzene and acetonitrile). These investigations indicated that FLP chemistry based on 1 is considerably less favored than that with B(C6F5)3. This is in agreement with control NMR experiments indicating hydride transfer from [H-B(Ohfip)3](-) upon reaction with B(C6F5)3, giving [H-B(C6F5)3](-) and B(Ohfip)3 in toluene and also MeCN. Induced by these unsuccessful reactions, the Lewis acidity towards HSAB hard and soft ions was investigated for gaining a deeper insight. A unified reference system based on the trimethylsilyl compounds Me3Si-Y (Y = F, Cl, H, Me) and their respective ions Me3Si(+)/Y(-) calculated at the G3 level was chosen as the anchor point. The individual ion affinities were then assessed based on subsequent isodesmic reactions calculated at a much less expensive level (RI-)BP86/SV(P). This method was validated by systematic calculations of smaller reference systems at the frozen core CCSD(T) level with correlation effects extrapolated to a full quadruple-ζ basis. Overall, 33 common and frequently used Lewis acids were ranked with respect to their FIA, CIA, HIA and MIA (fluoride/chloride/hydride/methyl ion affinity).

  3. Bioconversion enhancement of conjugated linoleic acid by Lactobacillus plantarum using the culture media manipulation and numerical optimization.

    Science.gov (United States)

    Khosravi, Azin; Safari, Mohammad; Khodaiyan, Faramarz; Gharibzahedi, Seyed Mohammad Taghi

    2015-09-01

    The ability of different Lactobacillus strains to produce conjugated linoleic acid (CLA) from linoleic acid was evaluated. Preliminary experiments revealed that L. plantarum among the screened strains had the highest CLA-producing potential (95.25 μg/mL). The cell growth of this bacterium was studied in three media of MRS broth, skim milk and skim milk supplemented with yeast extract and glucose. Results showed that the use of yeast extract and glucose could significantly increase the cell growth and CLA production. Response surface methodology (RSM) was applied to investigate the effects of three independent variables; linoleic acid (LA), yeast extract concentrations and inoculum size on the CLA formation. A second-order polynomial model with high R (2) value (0.981) was developed using multiple linear regression analysis. The optimum conditions to achieve the highest CLA production (240.69 μg/mL) was obtained using 3 mg/mL LA, 4 g/L yeast extract and inoculum size of 4 % v/v. CLA concentration of the optimal sample was analyzed by Gas Chromatography (GC). The cis-9, trans-11 CLA was the major CLA isomer of total CLA detected.

  4. Experimental Study and Numerical Solution of Poly Acrylic Acid Supported Magnetite Nanoparticles Transport in a One-Dimensional Porous Media

    Directory of Open Access Journals (Sweden)

    M. Golzar

    2014-01-01

    Full Text Available Recently, iron nanoparticles have attracted more attention for groundwater remediation due to its potential to reduce subsurface contaminants such as PCBs, chlorinated solvents, and heavy metals. The magnetic properties of iron nanoparticles cause to attach to each other and form bigger colloid particles of iron nanoparticles with more rapid sedimentation rate in aqueous environment. Using the surfactants such as poly acrylic acid (PAA prevents iron nanoparticles from forming large flocs that may cause sedimentation and so increases transport distance of the nanoparticles. In this study, the transport of iron oxide nanoparticles (Fe3O4 stabilized with PAA in a one-dimensional porous media (column was investigated. The slurries with concentrations of 20,100 and 500 (mg/L were injected into the bottom of the column under hydraulic gradients of 0.125, 0.375, and 0.625. The results obtained from experiments were compared with the results obtained from numerical solution of advection-dispersion equation based on the classical colloid filtration theory (CFT. The experimental and simulated breakthrough curves showed that CFT is able to predict the transport and fate of iron oxide nanoparticles stabilized with PAA (up to concentration 500 ppm in a porous media.

  5. Direct Capture of Organic Acids From Fermentation Media Using Ionic Liquids

    Energy Technology Data Exchange (ETDEWEB)

    Klasson, K.T.

    2004-11-03

    Several ionic liquids have been investigated for the extraction of organic acids from fermentation broth. Partitioning of representative organic acids (lactic, acetic, and succinic) between aqueous solution and nine hydrophobic ionic liquids was measured. The extraction efficiencies were strongly dependent on pH of the aqueous phase. Distribution coefficient was very good (approximately 60) at low succinic acid concentrations for one of the ionic liquids (trihexyltetradecylphosphonium methanesulfonate) at neutral pH. However, this ionic liquid had to be diluted with nonanol due to its high viscosity in order to be useful. A diluent (trioctylamine) was also added to this mixture. The results suggest that an extraction system based on ionic liquids may be feasible for succinic acid recovery from fermentation broth and that two ideal extraction stages are needed to reduce the concentration from 33 g/L to 1 g/L of succinic acid. Further studies are needed to evaluate other issues related to practical applications, including ionic liquid loss in the process, toxicity effects of ionic liquids during simultaneous fermentation and extractions.

  6. Flame retardant wool using zirconium oxychloride in various acidic media optimized by RSM

    Energy Technology Data Exchange (ETDEWEB)

    Forouharshad, M., E-mail: Forouharmahdi@gmail.com [Textile Department, Islamic Azad University South Tehran Branch, Tehran (Iran, Islamic Republic of); Montazer, M., E-mail: tex5mm@aut.ac.ir [Textile Department, Center of Excellence, Amirkabir University of Technology, Tehran (Iran, Islamic Republic of); Moghadam, M.B. [Department of Statistics, Allameh-Tabataba' i University, Tehran (Iran, Islamic Republic of); Saligheh, O. [Textile Department, Islamic Azad University South Tehran Branch, Young Researchers Club, Tehran (Iran, Islamic Republic of)

    2011-03-20

    Research highlights: {yields} We investigate effect of ZrOCl{sub 2} and HCl on the flame retardancy of wool fabric. {yields} The response surface methodology uses for the experimental plan with. {yields} The thermal degradation studies by thermal analysis, LOI and vertical flame test. {yields} The fabric surfaces observe by SEM. {yields} Results show an increase in the decomposition temperature, residual mass and LOI. - Abstract: The flame retardant wool was prepared using zirconium oxychloride with various acids. The thermal degradation of wool treated with the flame retardant synergistic system, zirconium oxychloride, citric acid and hydrochloric acid, was studied by thermal analysis, mass loss, limiting oxygen index (LOI) and vertical flame test. The fabric surfaces were also observed by SEM. The wool treated with the flame-retardant shows an increase in the decomposition temperature, residual mass and LOI. Also the wool treated with hydrochloric acid showed improved flame retardant properties compared to the use of formic acid. The response surface methodology (RSM) was also used for the experimental plan with four variables on the results of flame retardancy. The statistical analysis confirms the optimum conditions obtained by the experimental results.

  7. Time-resolved fluorescence of cationic dyes covalently bound to poly(methacrylic acid) in rigid media

    Energy Technology Data Exchange (ETDEWEB)

    Paulo Moises de Oliveira, Hueder [Instituto de Quimica de Sao Carlos, Universidade de Sao Paulo, Sao Carlos, SP (Brazil); Gehlen, Marcelo Henrique [Instituto de Quimica de Sao Carlos, Universidade de Sao Paulo, Sao Carlos, SP (Brazil)]. E-mail: marcelog@iqsc.usp.br

    2006-12-15

    Atactic poly(methacrylic acid) labeled with acridine and Nile blue (NB) were studied by photophysical techniques in bulk solid state and in solution-cast films over different surfaces (glass, ITO, and polymethylmethacrylate). In the systems with both dyes, energy transfer from acridine to NB occurs with an efficiency depending on the type of substrate (solid or film). The films are more disordered fluorescent rigid media than the bulk chromophoric or bichromophoric polymers, and this effect is ascribed to inhomogeneous distribution of the dyes in the film. This effect enhances dye bimolecular interactions and increases the energy transfer rates between acridine donor and NB acceptor. Bimodal distributions of donor fluorescence lifetimes are observed.

  8. Nanoporous gold on three-dimensional nickel foam: An efficient hybrid electrode for hydrogen peroxide electroreduction in acid media

    Science.gov (United States)

    Ke, Xi; Xu, Yantong; Yu, Changchun; Zhao, Jie; Cui, Guofeng; Higgins, Drew; Li, Qing; Wu, Gang

    2014-12-01

    A hybrid structure of nanoporous gold (NPG) on three-dimensional (3D) macroporous Ni foam has been synthesized by electrodeposition of Au-Sn alloy film followed by a facile chemical dealloying process under free corrosion conditions. Scanning electron microscopy (SEM) and X-ray diffraction (XRD) are used to characterize the morphology and structure of the NPG/Ni foam hybrids. It is shown that the Ni foam skeletons are uniformly wrapped by the NPG film which is composed of bicontinuous nanostructures consisting of interconnected ligaments and nanopores. Electroreduction of H2O2 on the NPG/Ni foam hybrid electrode in acid media is investigated by linear scan voltammetry, chronoamperometry and electrochemical impedance spectroscopy. It is found that such hierarchical porous electrode displays superior activity, durability and mass transport property for H2O2 electroreduction. These results demonstrate the potential of the NPG/Ni foam hybrid electrodes for the applications in fuel cell technology.

  9. Protonation Equilibria of L-Aspartic, Citric and Succinic Acids in Anionic Micellar Media

    Directory of Open Access Journals (Sweden)

    P. Srinivasa Rao

    2009-01-01

    Full Text Available The impact of sodium lauryl sulphate (SLS on the protonation equilibria of L-aspartic acid, citric acid and succinic acid has been studied in various concentrations (0.5-2.5% w/v of SLS solution maintaining an ionic strength of 0.16 mol dm-3 at 303 K. The protonation constants have been calculated with the computer program MINIQUAD75 and the best fit models have been calculated based on statistical parameters. The trend of log values of step-wise protonation constants with mole fraction of the medium has been explained based on electrostatic and non-electrostatic forces operating on the protonation equilibria. The effects of errors on the protonation constants have also been presented.

  10. The corrosion behaviour of WC-VC-Co hardmetals in acidic media

    Energy Technology Data Exchange (ETDEWEB)

    Konadu, D.S.; Merwe, J. van der [DST/NRF Centre of Excellence in Strong Materials, School of Chemical and Metallurgical Engineering, University of the Witwatersrand, P.O. Private Bag 3, WITS 2050 (South Africa); Potgieter, J.H. [School of Biology, Chemistry and Health Sciences, Division of Chemistry and Materials, Manchester Metropolitan University, Oxford Road, Manchester M 1 5GD (United Kingdom); Potgieter-Vermaak, S. [School of Chemistry, University of the Witwatersrand, P.O. Private Bag 3, WITS 2050 (South Africa); Machio, C.N., E-mail: cmachio@csir.co.z [Council for Scientific and Industrial Research (CSIR), Materials Science and Manufacturing, P.O. Box 395, PRETORIA 0001 (South Africa)

    2010-09-15

    The effect of increasing vanadium carbide (VC) content on the corrosion behaviour of tungsten carbide - 10 wt% cobalt hardmetals was investigated in 1 M hydrochloric (HCl), and sulphuric (H{sub 2}SO{sub 4}) acids solutions. Increasing VC content makes the open circuit potential (OCP) in the test solutions more negative than the base alloy. Specimens exhibited pseudo passivation in all the test solutions. Increasing VC led to decreasing corrosion current density. However, the corrosion current densities during chronoamperometric tests were lower for 0 wt% VC. XRD and Raman spectroscopy showed that hydrated WO{sub 3} formed in the surface films of all specimens in hydrochloric acid (HCl), while hydrated vanadyl sulphate also formed for higher VC content specimens in sulphuric acid (H{sub 2}SO{sub 4}).

  11. Interactions of short chain phenylalkanoic acids within ionic surfactant micelles in aqueous media

    Directory of Open Access Journals (Sweden)

    Naeem Kashif

    2012-01-01

    Full Text Available % SDS KR nema Solubilization and interactions of phenylalkanoic acids induced by cationic surfactant, cetyltrimethylammonium bromide (CTAB and an anionic surfactant, sodium dodecyl sulfate (SDS was investigated spectrophotometrically at 25.0°C. The UV spectra of the additives (acids were measured with and without surfactant above and below critical micelle concentration (cmc of the surfactant. The presence of alkyl chain in phenylalkanoic acids is responsible for hydrophobic interaction resulting in shift of the spectra towards longer wavelength (red shift. The value of partition coefficient (Kx between the bulk water and surfactant micelles and in turn standard free energy change of solubilization (ΔGpº were also estimated by measuring the differential absorbance (ΔA of the additives in micellar solutions.

  12. Use of fatty acid methyl ester profiles for discrimination of Bacillus cereus T-strain spores grown on different media.

    Science.gov (United States)

    Ehrhardt, Christopher J; Chu, Vivian; Brown, TeeCie; Simmons, Terrie L; Swan, Brandon K; Bannan, Jason; Robertson, James M

    2010-03-01

    The goal of this study was to determine if cellular fatty acid methyl ester (FAME) profiling could be used to distinguish among spore samples from a single species (Bacillus cereus T strain) that were prepared on 10 different medium formulations. To analyze profile differences and identify FAME biomarkers diagnostic for the chemical constituents in each sporulation medium, a variety of statistical techniques were used, including nonmetric multidimensional scaling (nMDS), analysis of similarities (ANOSIM), and discriminant function analysis (DFA). The results showed that one FAME biomarker, oleic acid (18:1 omega9c), was exclusively associated with spores grown on Columbia agar supplemented with sheep blood and was indicative of blood supplements that were present in the sporulation medium. For spores grown in other formulations, multivariate comparisons across several FAME biomarkers were required to discern profile differences. Clustering patterns in nMDS plots and R values from ANOSIM revealed that dissimilarities among FAME profiles were most pronounced when spores grown with disparate sources of complex additives or protein supplements were compared (R > 0.8), although other factors also contributed to FAME differences. DFA indicated that differentiation could be maximized with a targeted subset of FAME variables, and the relative contributions of branched FAME biomarkers to group dissimilarities changed when different media were compared. When taken together, these analyses indicate that B. cereus spore samples grown in different media can be resolved with FAME profiling and that this may be a useful technique for providing intelligence about the production methods of Bacillus organisms in a forensic investigation.

  13. Preparation of Butyl Chloride from Butanol and Hydrochloric Acid Using Ionic Liquids as Catalyst%离子液体催化丁醇与盐酸反应制备丁基氯

    Institute of Scientific and Technical Information of China (English)

    孙爱军; 聂毅; 李春喜; 王子镐

    2008-01-01

    The catalytic performance of some quaternary ammonium salts for the liquid phase reaction of butanol and hydrochloric acid at different conditions was studied experimentally and compared with the traditional catalyst (ZnC12). The organic ammonium catalysts investigated include ionic liquids N-butyl-N-methyl imidazolium fluobo-rate ([BMIM][BF4]) and N-butyl-N-methylimidazolium chloride ([BMIM]Cl) as well as hydrochloric salts of N-methylimidazol ([HMIM]Cl), pyridine ([Hpy]Cl) and triethylamine ([HEt3N]Cl). It is shown that the intrinsic catalytic performance of all organic ammonium salts except [Het3N]Cl is slightly superior to ZnCl2, while the se-lectivity of butyl chloride is nearly at the same level around 96%. The conversion of butanol increases slightly with temperature and the catalyst amount added while the variation of selectivity is not obvious. Based on the recycle experiments, the ionic liquids as catalyst for the reaction of butanol and hydrochloric acid can be used more than 5 times, which suggests great potential of using ionic liquids as novel catalyst for such reactions.

  14. Dissolution properties of co-amorphous drug-amino acid formulations in buffer and biorelevant media

    DEFF Research Database (Denmark)

    Heikkinen, A. T.; DeClerck, L.; Löbmann, K

    2015-01-01

    -amorphous formulations have been tested only in buffers and their supersaturation ability remain unexplored. Consequently, dissolution studies in simulated intestinal fluids need to be conducted in order to better evaluate the potential of these systems in increasing the oral bioavailability of biopharmaceutics...... classification system class II drugs. In this study, solubility and dissolution properties of the co-amorphous simvastatin-lysine, gibenclamide-serine, glibenclamide-threonine and glibenclamide-serine-threonine were studied in phosphate buffer pH 7.2 and biorelevant media (fasted and fed state simulated...... intestinal fluids (FaSSIF and FeSSIF, respectively)). The co-amorphous formulations were found to provide a long-lasting supersaturation and improve the dissolution of the drugs compared to the crystalline and amorphous drugs alone in buffer. Similar improvement, but in lesser extent, was observed...

  15. Dissolution properties of co-amorphous drug-amino acid formulations in buffer and biorelevant media

    DEFF Research Database (Denmark)

    Heikkinen, A. T.; DeClerck, L.; Löbmann, Korbinian

    2015-01-01

    -amorphous formulations have been tested only in buffers and their supersaturation ability remain unexplored. Consequently, dissolution studies in simulated intestinal fluids need to be conducted in order to better evaluate the potential of these systems in increasing the oral bioavailability of biopharmaceutics...... classification system class II drugs. In this study, solubility and dissolution properties of the co-amorphous simvastatin-lysine, gibenclamideserine, glibenclamide-threonine and glibenclamide-serine-threonine were studied in phosphate buffer pH 7.2 and biorelevant media (fasted and fed state simulated...... intestinal fluids (FaSSIF and FeSSIF, respectively)). The co-amorphous formulations were found to provide a long-lasting supersaturation and improve the dissolution of the drugs compared to the crystalline and amorphous drugs alone in buffer. Similar improvement, but in lesser extent, was observed...

  16. Preparation of semisynthetic (+)-tubocurarine chloride.

    Science.gov (United States)

    Naghaway, J; Soine, T O

    1979-05-01

    Semisynthetic (+)-tubocurarine chloride (II) was prepared by monoquaternization of (+)-tubocurine. The method involved treating (+)-tubocurine with a 0.5 M equivalent of hydrochloric acid prior to quaternization with methyl iodide, followed by neutralization and iodide-chloride ion-exchange. Column chromatography and crystallization procedures were utilized for pure semisynthetic II preparation. The neuromuscular junction blocking activities of the semisynthetic and commercial II were determined by the in vivo cat hypoglossal nerve-tongue muscle preparation. No delectable differences among physical constants, spectral data, and neuromuscular junction blocking activities were noted between the commercial product and the semisynthetic II. This result substantiates the chemical and biological data for the well-accepted new formula for II. The unexplained M + n14 mass spectral peaks shown by the curare-type bases are characteristic of the molecular species rather than a result of contaminants.

  17. Theoretical study of inhibition efficiencies of some amino acids on corrosion of carbon steel in acidic media: green corrosion inhibitors.

    Science.gov (United States)

    Dehdab, Maryam; Shahraki, Mehdi; Habibi-Khorassani, Sayyed Mostafa

    2016-01-01

    Inhibition efficiencies of three amino acids [tryptophan (B), tyrosine (c), and serine (A)] have been studied as green corrosion inhibitors on corrosion of carbon steel using density functional theory (DFT) method in gas and aqueous phases. Quantum chemical parameters such as EH OMO (highest occupied molecular orbital energy), E LUMO (lowest unoccupied molecular orbital energy), hardness (η), polarizability ([Formula: see text]), total negative charges on atoms (TNC), molecular volume (MV) and total energy (TE) have been calculated at the B3LYP level of theory with 6-311++G** basis set. Consistent with experimental data, theoretical results showed that the order of inhibition efficiency is tryptophan (B) > tyrosine (C) > serine (A). In order to determine the possible sites of nucleophilic and electrophilic attacks, local reactivity has been evaluated through Fukui indices.

  18. Chloride ingress prediction

    DEFF Research Database (Denmark)

    Frederiksen, Jens Mejer; Geiker, Mette Rica

    2008-01-01

    Prediction of chloride ingress into concrete is an important part of durability design of reinforced concrete structures exposed to chloride containing environment. This paper presents experimentally based design parameters for Portland cement concretes with and without silica fume and fly ash...... in marine atmospheric and submersed South Scandinavian environment. The design parameters are based on sequential measurements of 86 chloride profiles taken over ten years from 13 different types of concrete. The design parameters provide the input for an analytical model for chloride profiles as function...

  19. Effect of triamcinolone acetonide ammonia bromine joint hydrochloric acid on patients with secretory otitis media and on body's inflammatory factor and cellular immunologic parameters

    Institute of Scientific and Technical Information of China (English)

    Quan-Fu Hu; Shao-Ji Ouyang; Rong-Wei Yao; Xue-Jiang Xu; Jin-Hua He; Li-Li Zhang

    2016-01-01

    Objective:To explore the clinical effect of triamcinolone acetonide ammonia bromine joint hydrochloric acid on patients with secretory otitis media and the influences on the body's inflammatory factors and cellular immunologic parameters.Methods:A total of 40 cases of single ear secretory otitis media patients of the same period in our hospital were randomly selected as experimental group, using triamcinolone acetonide ammonia bromine joint hydrochloric acid treatment; And 40 cases of single ear secretory otitis media patients of the same period were randomly selected as control group, using dexamethasone treatment. To observe the clinical efficacy of two groups of patients and detect the inflammatory factors and cellular immune index level of the two groups of patients before and after treatment.Results:The total effective rate(90%) of treatment group is significantly higher than that (80%) of control group (P0.05). After treatment, the serum and ear effusion inflammatory cytokines levels of the two groups were significantly lower than that before treatment (P0.05); The CD4+/CD8+ levels of experimental group were significantly higher than the control group (P0.05). Conclusions: The triamcinolone acetonide ammonia bromine joint hydrochloric acid treatment is more conducive to improve the immune function of the secretory otitis media patients and treatment effect, which has important clinical significance on the treatment of secretory otitis media patients.

  20. Solvent Acidity and Basicity in Polar Media and their Role in Solvation

    Science.gov (United States)

    1994-04-20

    statistically less useful in LSERs (see Table 1). A related acidity scale is the Kosower Z which is based on the absorption bond associated with an...Koninklinge Dana. Vidensk. Selsk., 7 (1926). 12. U. Mayer, V. Gutmann, and W. Gerger, Monatsh. Chem., 106 (1975) 1235. 13. E.M. Kosower , J. Am. Chem. Soc

  1. Effect of different media on production of lactic acid from whey by ...

    African Journals Online (AJOL)

    STORAGESEVER

    2009-01-05

    Jan 5, 2009 ... highest lactic acid production (20.8 g/l) and rate of productivity (0.304 g/l.h) was achieved when the volume percent ..... tation cannot utilize the high feed (sugar) concentration, and whey without ... in continuous fermentation.

  2. Polymerization of euphorbia oil with Lewis acid in carbon dioxide media

    Science.gov (United States)

    Boron trifluoride diethyl etherate (BF3-OEt2) Lewis acid catalyzed ring-opening polymerization of euphorbia oil (EO), a natural epoxy oil, in liquid carbon dioxide was conducted in an effort to develop useful vegetable oil based polymers. The resulting polymers (RPEO) were characterized by FTIR, 1H-...

  3. Corrosion behaviour of WC-VC-Co hardmetals in acidic media

    CSIR Research Space (South Africa)

    Konadu, DS

    2010-09-01

    Full Text Available The effect of increasing vanadium carbide (VC) content on the corrosion behaviour of tungsten carbide – 10 wt% cobalt hard metals was investigated in 1 M hydrochloric (HCl), and sulphuric (H2SO4) acids solutions. Increasing VC content makes the open...

  4. Transformations of polyols to organic acids and hydrogen in aqueous alkaline media

    NARCIS (Netherlands)

    Van Haasterecht, T.; Van Deelen, T. W.; De Jong, K. P.; Bitter, J. H.

    2014-01-01

    In this paper we show that carbon nanofiber supported copper and nickel nanoparticles can selectively transform ethylene glycol and glycerol into value added oxygenates (organic acids) under anaerobic aqueous conditions. During aqueous phase oxidation Cu based catalysts showed a nearly quantitative

  5. Corrosion behaviour of 6063 aluminium alloy in acidic and in alkaline media

    Directory of Open Access Journals (Sweden)

    Prabhu Deepa

    2017-05-01

    Full Text Available The corrosion behaviour of 6063 aluminium alloy was investigated in different concentrations of phosphoric acid medium and sodium hydroxide medium at different temperatures. The study was done by electrochemical method, using Tafel polarization technique and electrochemical impedance spectroscopy (EIS technique. The surface morphology was investigated using scanning electron microscope (SEM with Energy-dispersive X-ray spectroscopy (EDX. The results showed that the 6063 aluminium alloy undergoes severe corrosion in sodium hydroxide medium than in phosphoric acid medium. The corrosion rate of 6063 aluminium alloy increased with an increase in the concentration of acid as well as with alkali. The corrosion rate was increased with an increase in temperature. The kinetic parameters and thermodynamic parameters were calculated using Arrhenius theory and transition state theory. Suitable mechanism was proposed for the corrosion of 6063 aluminium alloy in phosphoric acid medium and sodium hydroxide medium. The results obtained by Tafel polarization and electrochemical impedance spectroscopy (EIS techniques were in good agreement with each other.

  6. Transformations of polyols to organic acids and hydrogen in aqueous alkaline media

    NARCIS (Netherlands)

    Haasterecht, van T.; Deelen, van T.W.; Jong, de K.P.; Bitter, J.H.

    2014-01-01

    In this paper we show that carbon nanofiber supported copper and nickel nanoparticles can selectively transform ethylene glycol and glycerol into value added oxygenates (organic acids) under anaerobic aqueous conditions. During aqueous phase oxidation Cu based catalysts showed a nearly quantitative

  7. Common buffers, media, and stock solutions.

    Science.gov (United States)

    2001-05-01

    This appendix describes the preparation of selected bacterial media and of buffers and reagents used in the manipulation of nucleic acids and proteins. Recipes for cell culture media and reagents are located elsewhere in the manual. RECIPES: Acids, concentrated stock solutions; Ammonium acetate, 10 M; Ammonium hydroxide, concentrated stock solution; ATP, 100 mM; BCIP, 5% (w/v); BSA (bovine serum albumin), 10% (100 mg/ml); Denhardt solution, 100x; dNTPs: dATP, dTTP, dCTP, and dGTP; DTT, 1 M; EDTA, 0.5 M (pH 8.0); Ethidium bromide solution; Formamide loading buffer, 2x; Gel loading buffer, 6x; HBSS (Hanks balanced salt solution); HCl, 1 M; HEPES-buffered saline, 2x; KCl, 1 M; LB medium; LB plates; Loading buffer; 2-ME, (2-mercaptoethanol)50 mM; MgCl(2), 1 M; MgSO(4), 1 M; NaCl, 5 M; NaOH, 10 M; NBT (nitroblue tetrazolium chloride), 5% (w/v); PCR amplification buffer, 10x; Phosphate-buffered saline (PBS), pH approximately 7.3; Potassium acetate buffer, 0.1 M; Potassium phosphate buffer, 0.1 M; RNase a stock solution (DNase-free), 2 mg/ml; SDS, 20%; SOC medium; Sodium acetate, 3 M; Sodium acetate buffer, 0.1 M; Sodium phosphate buffer, 0.1 M; SSC (sodium chloride/sodium citrate), 20x; SSPE (sodium chloride/sodium phosphate/EDTA), 20x; T4 DNA ligase buffer, 10x; TAE buffer, 50x; TBE buffer, 10x; TBS (Tris-buffered saline); TCA (trichloroacetic acid), 100% (w/v); TE buffer; Terrific broth (TB); TrisCl, 1 M; TY medium, 2x; Urea loading buffer, 2x.

  8. Development of partitioning method. Adsorption of cesium with mordenite in acidic media

    Energy Technology Data Exchange (ETDEWEB)

    Donnet, L.; Morita, Yasuji; Yamagishi, Isao; Kubota, Masumitsu [Japan Atomic Energy Research Inst., Tokai, Ibaraki (Japan). Tokai Research Establishment

    1998-10-01

    Adsorption of cesium with mordenite from a acidic solution, typically from a 0.5 mol/L nitric acid solution, was studied to examine the possibility to design a new separation scheme for partitioning of high-level liquid waste. Batch adsorption experiments showed that three mordenites examined (natural mordenite and two synthetic mordenites Zeolon 900Na and 900H) have very close behavior with the parameters of adsorption kinetics, the saturation capacity by Langmuir equation, the distribution coefficient of Cs and adsorption of other elements. In the Cs adsorption with the natural mordenite at 0.5 mol/L nitric acid, distribution coefficient was 1150 ml/g and the saturation capacity was 0.64 mmol/g. In the adsorption of Cs on column using the natural mordenite, the flow rate of the Cs solution modified only the 5% breakthrough point and gave no influence on the total capacity of Cs. Column experiments with a mixed solution of Cs, Rb, Na, Ba, Sr, Cr, Ni, Ru, Rh and Pd showed that cesium was adsorbed very selectively. Only about 4% of rubidium in a molar ratio were retained in the column. The total quantity of Cs and Rb adsorbed was 0.51 mmol/g at 0.5 mol/L nitric acid. Elution of Cs (and Rb) with 4 mol/L nitric acid was performed against the column of the loaded natural mordenite. The adsorbed Cs and Rb were well eluted, and a good mass balance was obtained between the adsorbed quantity by breakthrough curves and the quantity found in the eluate. (author)

  9. The behaviour of polyaniline-coated PVC membrane based on 7, 16-didecyl-1, 4, 10, 13-tetraoxa-7, 16-diazacyclooctadecane for pH measurements in highly acidic media

    Indian Academy of Sciences (India)

    R Ansari; M Arvand; L Heydari

    2014-01-01

    Polyaniline(PANI) chemically coated on poly(vinyl chloride) (PVC) membrane based on a neutral carrier 7,16-didecyl-1,4,10,13-tetraoxa-7,16-diazacyclooctadecane (kryptofix 22 DD) as the active component has been developed for determination of pH values ranging from pH 0.1-1. The effect of experimental parameters such as membrane composition, nature and amount of plasticizer, lipophilic additives and thickness of PANI film on the potential response of the pH electrode was investigated. The electrode has an apparent Nernstian response slope of 54.5 ± 0.4 mV pH-1 (at 20°C). The equilibrium water content of the electrode was determined in pure water and NaCl solution (I = 0.1 mol Kg-1). The electrode had low electric resistance, good potential stability and reproducibility (±1.5 mV, = 10). It has a rapid potential response to changes of pH (15 s). The excellent performance in terms of linearity, stability and fast response makes this device suitable for pH measurements in highly acidic media.

  10. Transport and Retention of TiO2 Rutile Nanoparticles in Saturated Porous Media: Influence of Solution pH, Ionic Strength, and the Presence of Humic Acid

    Science.gov (United States)

    The influence of solution pH, ionic strength, and varying concentrations of the Suwannee River Humic Acid (SRHA) on the transport of titanium dioxide (TiO2, rutile) nanoparticle aggregates (nTiO2) in saturated porous media was investigated through systematically examining the tra...

  11. Green Approach to Corrosion Inhibition of Mild Steel by Lignin Sulfonate in Acidic Media

    Institute of Scientific and Technical Information of China (English)

    Muna A.ABU-DALO; Nathir A.F.AL-RAWASHDEH; Ahmed A.MUTLAQ

    2016-01-01

    The inhibition effect of lignin sulfonate against corrosion for mild steel in acidic solution has been examined by means of FTIR (fourier transform infrared spectroscopy),FAA (flame atomic absorption)spectroscopy,SEM (scanning electron microscope),EDS (energy dispersive X-ray spectroscopy),and mass loss techniques.The results revealed that lignin is a beneficial inhibitor for mild steel corrosion in acidic medium.It has been further found that Langmuir adsorption isotherm is obeyed by the tested lignin′s adsorption over the surface of mild steel.The range of inhibition efficiency (IE)in 2 mol·L-1 HCl was found to be 75·88%-87·88% for Reax 88A,40·72%-60·32%for Reax 88B,and 54·32%-63·03% for Reax 100M,after immersed at 298 K for 24 h time.

  12. Effect of Different Electrode Materials on the Electropolymerization Process of Aniline in Nitric Acid Media

    Science.gov (United States)

    Li, Yaozong; Yi, Yun; Yang, Weifang; Liu, Xiaoqing; Li, Yuanyuan; Wang, Wei

    2016-11-01

    The electropolymerization process of aniline on different electrode surfaces such as Pt, Au, RuTi and polyaniline film in nitric acid solution containing 1 M aniline was investigated by cyclic voltammetry and electrochemical impedance spectroscopy. Proposed electrical equivalent circuits were used to give a further analysis. Results show that the electrode materials accelerate the aniline electropolymerization remarkably as a catalyst, especially the electrochemical oxidation process of monomer aniline to its cation radical, which is the key step to incur the electropolymerization reaction of aniline on the electrode surface. The polymerization of aniline on RuTi electrode has the lowest reaction resistance for its adsorption sites, and the catalytic effects of these different electrodes decrease in the order: RuTi > polyaniline film > Pt > Au. The results also show that several states of polyaniline films are formed during the potential linear scan process in nitric acid solution and the corresponding oxidation and reduction reaction are reversible.

  13. Influence of gelatin on corrosion behavior of copper in acid media

    Directory of Open Access Journals (Sweden)

    Todorović Dragiša A.

    2012-01-01

    Full Text Available This paper presents the results of gelatin and benzotriazole (BTA inhibitory action on copper in the acid medium by the method of weight loss. The investigation was carried out in the citric acid solution (1, 5 and 20% at the temperature of 293 K. Under such conditions, the gelatin showed higher efficiency of corrosion protection in comparison to BTA. The results, obtained through the Gibbs and Langmuir adsorption isotherm, show that gelatin adsorption on copper surface obey the Langmuir adsorption isotherm model, as well as that the adsorption is a spontaneous process. The polarization measurements show the potential of full passivation shift towards more negative values, and the increase of corrosion current in both cases but being more pronounced with the BTA. The results obtained in this paper indicate that the inhibition gelatin can be used as the BTA substitute for the copper corrosion protection.

  14. Effect of Different Electrode Materials on the Electropolymerization Process of Aniline in Nitric Acid Media

    Science.gov (United States)

    Li, Yaozong; Yi, Yun; Yang, Weifang; Liu, Xiaoqing; Li, Yuanyuan; Wang, Wei

    2017-02-01

    The electropolymerization process of aniline on different electrode surfaces such as Pt, Au, RuTi and polyaniline film in nitric acid solution containing 1 M aniline was investigated by cyclic voltammetry and electrochemical impedance spectroscopy. Proposed electrical equivalent circuits were used to give a further analysis. Results show that the electrode materials accelerate the aniline electropolymerization remarkably as a catalyst, especially the electrochemical oxidation process of monomer aniline to its cation radical, which is the key step to incur the electropolymerization reaction of aniline on the electrode surface. The polymerization of aniline on RuTi electrode has the lowest reaction resistance for its adsorption sites, and the catalytic effects of these different electrodes decrease in the order: RuTi > polyaniline film > Pt > Au. The results also show that several states of polyaniline films are formed during the potential linear scan process in nitric acid solution and the corresponding oxidation and reduction reaction are reversible.

  15. The effect of caffeic acid phenethyl ester and thymoquinone on otitis media with effusion in rats.

    Science.gov (United States)

    Gülmez, Mehmet İhsan; Okuyucu, Şemsettin; Dokuyucu, Recep; Gökçe, Hasan

    2017-05-01

    In this study, we aimed to investigate the effect of CAPE and thymoquinone in experimental rat otitis media with effusion (OME) model. Intraoral approach of eustachian tube orifice cauterization were administered to 36 of 40 rats participating the study. After application of exclusion criterias, 22 rats with appropriate conditions were determined. Totally 26 rats (44 otitis model ears and 8 normal ears) were randomly divided into 5 groups. While group I was consisted of healthy rats, the other groups were consisted of rats with otitis model. Group I (saline + control group; n = 8 normal ears) and group II (saline + otitis model; n = 10 otitis model ears) received intraperitoneally saline solution. CAPE was given intraperitoneally to group III (CAPE + otitis model; n = 12 otitis model ears) at a concentration of 10 mg/kg for treatment of otitis media. Group IV (thymoquinone + otitis model; n = 12 otitis model ears) was treated orally with 10 mg/kg of thymoquinone. Group V (methylprednisolone + otitis model; n = 10 otitis model ears) was treated intraperitoneally with 1 mg/kg of methylprednisolone. Tympanic bulla samples were excised after 10th day of treatment and examined under light microscopy. Submucosal neutrophil leukocyte count of group I was significantly lower than other groups (II, IV, V) (respectively p < 0,0001, p < 0,001, p < 0,0001, Tukey test), while it was not significantly different from group III (p = 0,056, Tukey test). Submucosal neutrophil leukocyte count of group III was significantly lower than group II and group V (p = 0.029 ve p = 0.03, Tukey test). There was no significant difference between group IV and group V (p = 0,28, Tukey test). Based on these findings, it could be suggested that CAPE, anti inflammatory properties proven in the literature, plays an important role in OME treatment. Copyright © 2017 Elsevier B.V. All rights reserved.

  16. 注射用阿莫西林钠克拉维酸钾与氯化钠注射液配伍的稳定性%InjectedwithSodiumAmoxicillinClavulanicAcidPotassiumandSodiumChlorideInjectionCompatibilityStability

    Institute of Scientific and Technical Information of China (English)

    李艳红

    2013-01-01

    Objective To injection with sodium amoxicillin clavulanic acid potassium and sodium chloride injection compatibility stability was analyzed to explore, to provide a reference basis for the rational use of drugs in the future. Methods Select A batch of injection with sodium amoxicillin clavulanic acid potassium and sodium chloride injection for compatibility, and 3 hours after compatibility respectively under different temperature to observation of the appearance of the liquid, pH value, at the same time the method of high performance liquid chromatography (HPLC) amoxicillin clavulanic acid and sodium potassium content determination, determine the stability of compatibility of liquid. Results In the study found that sodium amoxicillin clavulanic acid potassium and sodium chloride injection compatibility stability is affected by the factors such as temperature and sunlight. Conclusion Poor compatibility stability of liquid, should avoid direct sunlight or at high temperatures is not easy to for a long time.%  目的对注射用阿莫西林钠克拉维酸钾与氯化钠注射液配伍稳定性进行分析探讨,为今后的合理用药提供参考依据。方法选取一批注射用阿莫西林钠克拉维酸钾和氯化钠注射液进行配伍,并在配伍后的3h内分别在不同温度下对药液的外观、pH值进行观察,同时采取高效液相色谱法对阿莫西林钠与克拉维酸钾含量进行测定,判断配伍液的稳定性。结果研究中发现阿莫西林钠克拉维酸钾与氯化钠注射液配伍稳定性受到温度、日光等因素的影响。结论配伍液稳定性不佳,应避免阳光直射或者是在高温条件下不易久置。

  17. Inhibition of the Corrosion of Mild Steel in Acid Media by Naturally Occurring Acacia Senegal

    Directory of Open Access Journals (Sweden)

    Urvija Garg

    2010-01-01

    Full Text Available The inhibition of corrosion of mild steel in HCl solution by naturally occurring Acacia Senegal has been studied in relation to the concentration of inhibitor and concentration of corrosive medium. It has been observed that the Acacia Senegal alcoholic extract acts as a good corrosion inhibitor in hydrochloric acid solution and the adsorption of the extract provides a good protection against mild steel corrosion.

  18. Corrosion behaviour of 6063 aluminium alloy in acidic and in alkaline media

    OpenAIRE

    Deepa, Prabhu; Padmalatha, Rao

    2017-01-01

    The corrosion behaviour of 6063 aluminium alloy was investigated in different concentrations of phosphoric acid medium and sodium hydroxide medium at different temperatures. The study was done by electrochemical method, using Tafel polarization technique and electrochemical impedance spectroscopy (EIS) technique. The surface morphology was investigated using scanning electron microscope (SEM) with Energy-dispersive X-ray spectroscopy (EDX). The results showed that the 6063 aluminium alloy und...

  19. Review and assessment of technologies for the separation of cesium from acidic media

    Energy Technology Data Exchange (ETDEWEB)

    Orth, R.J.; Brooks, K.P.; Kurath, D.E.

    1994-09-01

    A preliminary literature survey has been conducted to identify and evaluate methods for the separation of cesium from acidic waste. The most promising solvent extraction, precipitation, and ion exchange methods, along with some of the attributes for each method, are listed. The main criteria used in evaluating the separation methods were as follows: (1) good potential for cesium separation must be demonstrated (i.e., cesium decontamination factors on the order of 50 to 100). (2) Good selectivity for cesium over bulk components must be demonstrated. (3) The method must show promise for evolving into a practical and fairly simple process. (4) The process should be safe to operate. (5) The method must be robust (i.e., capable of separating cesium from various acidic waste types). (6) Secondary waste generation must be minimized. (7) The method must show resistance to radiation damage. The most promising separation methods did not necessarily satisfy all of the above criteria, thus key areas requiring further development are suggested for each method. The report discusses in detail these and other areas requiring further development, as well as alternative solvent extraction, precipitation, ion exchange, and {open_quote}other{close_quote} technologies that, based on current information, show less promise for the separation of cesium from acidic wastes because of significant process limitations. When appropriate, the report recommends areas of future development.

  20. Anticorrosive Activity of Kigelia pinnata Leaves Extract on Mild Steel in Acidic Media

    Science.gov (United States)

    Muthukrishnan, P.; Saravana Kumar, K.; Jeyaprabha, B.; Prakash, P.

    2014-09-01

    The corrosion inhibition of mild steel in 1 M H2SO4 and 1 M HCl solution with different concentrations of Kigelia pinnata leaves extract (KPLE) was investigated using mass loss, Tafel polarization, and electrochemical impedance spectroscopy. Inhibition efficiency of KPLE is found to increase with increasing concentration but to decrease with temperature. Polarization measurements reveal that KPLE acts as a mixed type inhibitor in both acids. Impedance curves show that increasing KPLE concentration increases charge transfer resistance and decreases double layer capacitance. The adsorption of KPLE on the mild steel surface obeys the Langmuir adsorption isotherm. The experimental results reveal that KPLE inhibits the corrosion reaction in both acid environments, and inhibition efficiency follows the order H2SO4 > HCl. The kinetic and adsorption parameters for mild steel in acid in the presence and absence of KPLE were evaluated and discussed. The negative value of the standard free energy of adsorption in the presence of inhibitor suggests spontaneous adsorption of inhibitor on the mild steel surface. Protective film formation against corrosion was confirmed by ultraviolet-visible (UV-visible), X-ray diffraction, scanning electron microscopy, and Fourier transform-infrared spectroscopy techniques.

  1. Extraction and separation of U(VI and Th(IV from hydrobromic acid media using Cyanex-923 extractant

    Directory of Open Access Journals (Sweden)

    Ghag Snehal M.

    2010-01-01

    Full Text Available A systematic study of the solvent extraction of uranium(VI and thorium(IV from hydrobromic acid media was performed using the neutral phosphine oxide extractant Cyanex-923 in toluene. These metal ions were found to be quantitatively extracted with Cyanex-923 in toluene in the acidity range 5x10-5-1x10-4 M and 5x10-5-5x10-3 M, respectively, and they are stripped from the organic phase with 7.0 M HClO4 and 2.0- 4.0 M HCl, respectively. The effect of the equilibrium period, diluents, diverse ions and stripping agent on the extraction of U(VI and Th(IV was studied. The stoichiometry of the extracted species of these metal ions was determined based on the slope analysis method. The extraction reactions proceed by solvation and their probable extracted species found in the organic phase were UO2Br2•2Cyanex-923 and ThBr4•2Cyanex-923. Based on these results, a sequential procedure for their separation from each other was developed.

  2. Separation and immobilization of Sr and Cs contained in acidic media by using inorganic ion-exchangers. Literature survey

    Energy Technology Data Exchange (ETDEWEB)

    Yamagishi, Isao [Japan Atomic Energy Research Inst., Tokai, Ibaraki (Japan). Tokai Research Establishment

    2001-07-01

    The present study deals with the survey of inorganic ion-exchangers suitable for separation and immobilization of Sr and Cs contained in acidic high-level liquid waste. The stabilities of published waste forms and their preparation processes were evaluated from the standpoint of conversion of exchangers containing Sr and Cs into appropriate waste forms. The essential results are below. (1) For separation and immobilization of Cs, crystalline silicotitanate seems to be the most promising exchanger. Insoluble ferrocyanides and phosphates are not suitable for immobilization without additives. Mordenite is inexpensive and commercially available but it would dissolve in highly acidic media. (2) For selective separation of Sr, there is no promising exchanger up to now. It is necessary either to modify separation condition or to synthesize a novel exchanger. (3) Soluble salts, glasses and ceramics are proposed as a storage or disposal form of separated Sr and Cs. Ceramics sintered by hot-pressing are favorable waste forms of inorganic ion-exchangers but their leachabilities and thermal conductivities are largely influenced by qualities of products. Crystallinity of a sintered exchanger depends on its composition. Exchanges of low Cs contents are often converted into amorphous materials whose chemical stabilities depend on solubilities of components of exchangers. (4) A new exchanger to be synthesized is crystalline and selective toward Sr and Cs. One meq/g is enough for Sr and Cs capacities, which are restricted by thermal and transmutation effects. Composition of the exchanger should be selected from the point of a scenario of separation and disposal. The solubilities of SiO{sub 2}, TiO{sub 2}, ZrO{sub 2}, Nb{sub 2}O{sub 5} and Ta{sub 2}O{sub 5} are low in acidic media and those of Al{sub 2}O{sub 3}, TiO{sub 2} and ZrO{sub 2}, in disposal circumstances. (5) Future works are optimization of separation scheme including development of exchangers, simplification of

  3. Enhanced anion electroadsorption into carbon molecular sieve electrodes in acidic media.

    Science.gov (United States)

    Eliad, Linoam; Salitra, Gregory; Pollak, Elad; Soffer, Abraham; Aurbach, Doron

    2005-11-08

    We previously showed that, for neutral electrolytes of small cations and relatively larger anions, it is possible to design certain pore sizes in active carbons that are large enough to electroadsorb cations but too small to allow anion electroadsorption. This situation leads to an electrical double-layer (EDL) capacitance that is significant only at potentials that are negative to the potential of zero charge (PZC); hence, much smaller capacitance is measured at potentials positive to the PZC. It was found that when the electrolyte is a strong acid (e.g., H(2)SO(4), HCl), a considerable capacitance is observed at positive potentials, even when the average pore size is too small to allow the insertion of large anions in neutral electrolyte solutions. This effect disappears when the pore size becomes considerably larger than the size of the ions. In this case, the EDL capacitance at positive potentials for both neutral and acidic solutions is comparable. The following four-step mechanism was found to comply best with the experimental data: (1) By acid catalysis, the protons form carbonium species within the conjugated carbon network. (2) The anions react with the carbonium ions, providing uncharged species in an activated state, which are chemibound as surface groups to the walls of the pores. (3) Because these surface groups are effectively much smaller in size than are the charged ions, they can migrate by chemical bond exchange within the carbon skeleton via constrictions (known to exist in microporous and molecular sieving carbons), which are too narrow to accommodate hydrated charged species. (4) Upon reaching wider spaces, the uncharged species are reionized and solvated by water molecules, which can fill small pores. The justification for the above mechanism is thoroughly discussed and demonstrated by the experimental results.

  4. The implications of particle energy and acidic media on gross alpha and gross beta determination using liquid scintillation

    Energy Technology Data Exchange (ETDEWEB)

    Zapata-Garcia, D. [Laboratori de Radiologia Ambiental (LRA), Departament de Quimica Analitica, Universitat de Barcelona, Marti i Franques, 1-11 Planta 3, E-08028 Barcelona (Spain); Llaurado, M., E-mail: montse.llaurado@ub.edu [Laboratori de Radiologia Ambiental (LRA), Departament de Quimica Analitica, Universitat de Barcelona, Marti i Franques, 1-11 Planta 3, E-08028 Barcelona (Spain); Rauret, G. [Laboratori de Radiologia Ambiental (LRA), Departament de Quimica Analitica, Universitat de Barcelona, Marti i Franques, 1-11 Planta 3, E-08028 Barcelona (Spain)

    2012-04-15

    The interaction of humans with radioactivity present in the environment from natural and artificial sources necessitates an evaluation of its risk on human health. Gross alpha and gross beta activities can provide a rapid evaluation of the radioactive content of a sample and can be simultaneously determined by using liquid scintillation counters. However, calibration of the liquid scintillation counter is required and is affected by many factors, such as particle energy and the acidity of the media. This study investigates what effect the particle energy used for calibration has on misclassification and how to account for this misclassification in routine measurements. The variability in measurement produced by the final pH, as well as any acids used in sample treatment, was also studied. These results showed that the most commonly used acid for these types of analyses, HNO{sub 3}, produced a high amount of misclassifications at very low pH. The results improved when HCl was used to adjust the sample to low pH. - Highlights: Black-Right-Pointing-Pointer We study the effect of alpha and beta energies on PSA optimisation. Black-Right-Pointing-Pointer The optimum PSA shifts to higher values as the alpha energy increases. Beta energies do not affect it. Black-Right-Pointing-Pointer We study the effect of pH on the simultaneous determination of gross alpha/beta activities. Black-Right-Pointing-Pointer HNO{sub 3} produces a high amount of misclassification at very low pH. Black-Right-Pointing-Pointer The results improve when HCl is used to adjust the sample to low pH.

  5. Influence of poly(aminoquinone) on corrosion inhibition of iron in acid media

    Science.gov (United States)

    Jeyaprabha, C.; Sathiyanarayanan, S.; Phani, K. L. N.; Venkatachari, G.

    2005-11-01

    The inhibitor performance of chemically synthesized water soluble poly(aminoquinone) (PAQ) on iron corrosion in 0.5 M sulphuric acid was studied in relation to inhibitor concentration using potentiodynamic polarization and electrochemical impedance spectroscopy measurements. On comparing the inhibition performance of PAQ with that of the monomer o-phenylenediamine (OPD), the OPD gave an efficiency of 80% for 1000 ppm while it was 90% for 100 ppm of PAQ. PAQ was found to be a mixed inhibitor. Besides, PAQ was able to improve the passivation tendency of iron in 0.5 M H 2SO 4 markedly.

  6. Novel method based on chromogenic media for discrimination and selective enumeration of lactic acid bacteria in fermented milk products.

    Science.gov (United States)

    Galat, Anna; Dufresne, Jérôme; Combrisson, Jérôme; Thépaut, Jérôme; Boumghar-Bourtchai, Leyla; Boyer, Mickaël; Fourmestraux, Candice

    2016-05-01

    Microbial analyses of fermented milk products require selective methods to discriminate between close species simultaneously present in high amounts. A culture-based method combining novel chromogenic agar media and appropriate incubation conditions was developed to enumerate lactic acid bacteria (LAB) strains in fermented milk. M1 agar, containing two chromogenic substrates, allowed selective enumeration of Lactobacillus rhamnosus, two strains of Lactobacillus paracasei subsp. paracasei and Streptococcus salivarius subsp. thermophilus based on differential β-galactosidase and β-glucosidase activities. Depending on the presence of some or all of the above strains, M1 agar was supplemented with L-rhamnose or vancomycin and incubations were carried out at 37 °C or 44 °C to increase selectivity. A second agar medium, M2, containing one chromogenic substrates was used to selectively enumerate β-galactosidase producing Lactobacillus delbrueckii subsp. bulgaricus at 47 °C. By contrast with the usual culture media, the chromogenic method allowed unambiguous enumeration of each species, including discrimination between the two L. paracasei, up to 10(9) CFU/g of fermented milk. In addition, the relevance of the method was approved by enumerating reference ATCC strains in pure cultures and fermented milk product. The method could also be used for enumerations on non-Danone commercial fermented milk products containing strains different from those used in this study, showing versatility of the method. To our knowledge, this is the first description of a chromogenic culture method applied to selective enumeration of LAB. Copyright © 2015 The Authors. Published by Elsevier Ltd.. All rights reserved.

  7. Acid/base front propagation in saturated porous media: 2D laboratory experiments and modeling

    Science.gov (United States)

    Loyaux-Lawniczak, Stéphanie; Lehmann, François; Ackerer, Philippe

    2012-09-01

    We perform laboratory scale reactive transport experiments involving acid-basic reactions between nitric acid and sodium hydroxide. A two-dimensional experimental setup is designed to provide continuous on-line measurements of physico-chemical parameters such as pH, redox potential (Eh) and electrical conductivity (EC) inside the system under saturated flow through conditions. The electrodes provide reliable values of pH and EC, while sharp fronts associated with redox potential dynamics could not be captured. Care should be taken to properly incorporate within a numerical model the mixing processes occurring inside the electrodes. The available observations are modeled through a numerical code based on the advection-dispersion equation. In this framework, EC is considered as a variable behaving as a conservative tracer and pH and Eh require solving the advection dispersion equation only once. The agreement between the computed and measured pH and EC is good even without recurring to parameters calibration on the basis of the experiments. Our findings suggest that the classical advection-dispersion equation can be used to interpret these kinds of experiments if mixing inside the electrodes is adequately considered.

  8. An improved extraction chromatographic resin for the separation of uranium from acidic nitrate media

    Energy Technology Data Exchange (ETDEWEB)

    Dietz, M.L.; Horwitz, E.P.; Sajdak, L.R.; Chiarizia, R. [Chemistry Division, Argonne National Laboratory, 60439 Argonne, IL (United States)

    2001-07-06

    The preparation and characterization of a new extraction chromatographic resin exhibiting extraordinarily strong retention of hexavalent uranyl ion over a wide range of nitric acid concentrations and very high selectivity for U(VI) over Fe(III) and numerous other cations is described. This new material (designated U/TEVA-2) comprises a novel liquid stationary phase consisting of an equimolar mixture of diamyl amylphosphonate (DA[AP]) and Cyanex 923{sup registered} (a commercially available trialkyl-phosphine oxide, TRPO) sorbed on silanized silica or Amberchrom CG-71. Cyanex 923 is shown to be preferable to a related TRPO, Cyanex 925{sup registered}, due to its lower viscosity and higher selectivity for U(VI) over Fe(III). The retention of uranyl nitrate by the U/TEVA-2 resin, as measured by the k' values (number of free column values to peak maximum) is >5000 from approximately 0.1 to 8 M HNO{sub 3}. The ability of the new resin to strongly and selectively retain U(VI) from such a wide range of acid concentrations, along with its favorable physical properties, make it a good candidate for application in the separation and preconcentration of U(VI) from complex environmental, biological, and nuclear waste samples for subsequent determination.

  9. An improved extraction chromatographic resin for the separation of uranium from acidic nitrate media.

    Science.gov (United States)

    Dietz, M L; Horwitz, E P; Sajdak, L R; Chiarizia, R

    2001-07-01

    The preparation and characterization of a new extraction chromatographic resin exhibiting extraordinarily strong retention of hexavalent uranyl ion over a wide range of nitric acid concentrations and very high selectivity for U(VI) over Fe(III) and numerous other cations is described. This new material (designated U/TEVA-2) comprises a novel liquid stationary phase consisting of an equimolar mixture of diamyl amylphosphonate (DA[AP]) and Cyanex 923((R)) (a commercially available trialkyl-phosphine oxide, TRPO) sorbed on silanized silica or Amberchrom CG-71. Cyanex 923 is shown to be preferable to a related TRPO, Cyanex 925((R)), due to its lower viscosity and higher selectivity for U(VI) over Fe(III). The retention of uranyl nitrate by the U/TEVA-2 resin, as measured by the k' values (number of free column values to peak maximum) is >5000 from approximately 0.1 to 8 M HNO(3). The ability of the new resin to strongly and selectively retain U(VI) from such a wide range of acid concentrations, along with its favorable physical properties, make it a good candidate for application in the separation and preconcentration of U(VI) from complex environmental, biological, and nuclear waste samples for subsequent determination.

  10. Sensory characterisation and consumer acceptability of potassium chloride and sunflower oil addition in small-caliber non-acid fermented sausages with a reduced content of sodium chloride and fat.

    Science.gov (United States)

    Mora-Gallego, Héctor; Guàrdia, Maria Dolors; Serra, Xavier; Gou, Pere; Arnau, Jacint

    2016-02-01

    The effect of the simultaneous reduction of fat proportion (from 20% to 10% and 7%) and added salt (from 2.5% to 1.5%) and the subsequent addition of 0.64% KCl and sunflower oil (1.5% and 3.0%) on the physicochemical, instrumental colour and texture, sensory properties and consumer acceptability of small caliber non-acid fermented sausages (fuet type) was studied. This simultaneous reduction of fat and salt increased weight loss, moisture, water activity (aw), redness, instrumental texture parameters (hardness, chewiness and cohesiveness), sensory attributes (darkness, hardness, elasticity) and the consumer acceptability. The subsequent addition of 0.64% KCl to the leanest batch decreased the aw and barely affected instrumental texture parameters and consumer acceptability. Subsequent sunflower oil addition decreased hardness, chewiness and cohesiveness and increased crumbliness and oil flavour which may decrease the consumer acceptability. The simultaneous reduction of fat and NaCl with the addition of 0.64% KCl was the preferred option by the consumers.

  11. Separation of middle rare earths by solvent extraction using 2-ethylhexylphosphonic acid mono-2-ethylhexyl ester as an extractant

    Institute of Scientific and Technical Information of China (English)

    Danilo; Fontana; Loris; Pietrelli

    2009-01-01

    The extraction of the trivalent middle rare earths from chloride media by kerosene solutions of 2-ethylhexylphosphonic acid mono-2-ethylhexyl ester as an extractant was studied. The separation factors between the elements using solution simulating wastes from NiMH spent batteries have been evaluated: the order of the extractive ability of extractant can be confirmed in ThGdEuSm.

  12. Re-cultivation of Neochloris oleoabundans in exhausted autotrophic and mixotrophic media: the potential role of polyamines and free fatty acids.

    Science.gov (United States)

    Sabia, Alessandra; Baldisserotto, Costanza; Biondi, Stefania; Marchesini, Roberta; Tedeschi, Paola; Maietti, Annalisa; Giovanardi, Martina; Ferroni, Lorenzo; Pancaldi, Simonetta

    2015-12-01

    Neochloris oleoabundans (Chlorophyta) is widely considered one of the most promising microalgae for biotechnological applications. However, the large-scale production of microalgae requires large amounts of water. In this perspective, the possibility of using exhausted growth media for the re-cultivation of N. oleoabundans was investigated in order to simultaneously make the cultivation more economically feasible and environmentally sustainable. Experiments were performed by testing the following media: autotrophic exhausted medium (E+) and mixotrophic exhausted medium after cultivation with glucose (EG+) of N. oleoabundans cells grown in a 20-L photobioreactor (PBR). Both exhausted media were replenished with the same amounts of nitrate and phosphate as the control brackish medium (C). Growth kinetics, nitrate and phosphate consumption, photosynthetic pigments content, photosynthetic efficiency, cell morphology, and lipid production were evaluated. Moreover, the free fatty acid (FFA) composition of exhausted media and the polyamine (PA) concentrations of both algae and media were analyzed in order to test if some molecules, released into the medium, could influence algal growth and metabolism. Results showed that N. oleoabundans can efficiently grow in both exhausted media, if appropriately replenished with the main nutrients (E+ and EG+), especially in E+ and to the same extent as in C medium. Growth promotion of N. oleoabundans was attributed to PAs and alteration of the photosynthetic apparatus to FFAs. Taken together, results show that recycling growth medium is a suitable solution to obtain good N. oleoabundans biomass concentrations, while providing a more sustainable ecological impact on water resources.

  13. Compound amino acids added in media improved Solanum nigrum L. phytoremediating CD-PAHS contaminated soil.

    Science.gov (United States)

    Wei, Shuhe; Bai, Jiayi; Yang, Chuanjie; Zhang, Qianru; Knorrm, Klaus-Holger; Zhan, Jie; Gao, Qianhui

    2016-01-01

    Cd hyperaccumulator Solanum nigrum L. was a promising plant used to simultaneously remediate Cd-PAHs combined pollution soil through its extra accumulation capacity and rhizosphere degradation. This article compared the strengthening remediation role of cysteine (Cys), glycine (Gly) and glutamic acid (Glu) with EDTA and TW80. The results showed that the addition of 0.03 mmol L(-1) Cys, Gly, and Glu didn't significantly impact (p Cd concentration. Therefore, Cd capacity (µg pot(-1)) in shoots of S. nigrum was significantly increased (p Cd might lie in the addition of Cys, Gly, and Glu which reduced pH and increased extractable Cd concentration in rhizosphere and phytochelatines (PCs) concentration in leaves. As for the degradation of PAHs in rhizosphere, increased microorganism number might be play important role.

  14. Evaluation of ability of ferulic acid to control growth and fumonisin production of Fusarium verticillioides and Fusarium proliferatum on maize based media.

    Science.gov (United States)

    Ferrochio, Laura; Cendoya, Eugenia; Farnochi, María Cecilia; Massad, Walter; Ramirez, María Laura

    2013-10-15

    The aim of this study was to evaluate the efficacy of ferulic acid (1, 10, 20 and 25 mM) at different water activity (aw) values (0.99, 0.98, 0.96 and 0.93) at 25 °C on growth and fumonisin production by Fusarium verticillioides and Fusarium proliferatum on maize based media. For both Fusarium species, the lag phase significantly decreased (p ≤ 0.001), and the growth rates increased (p ≤ 0.001) at the lowest ferulic acid concentration used (1mM), regardless of the aw. However, high doses of ferulic acid (10 to 25 mM) significantly reduced (p ≤ 0.001) the growth rate of both Fusarium species, regardless of the a(w). In general, growth rate inhibition increased as ferulic acid doses increased and as media aw decreased. Fumonisin production profiles of both Fusarium species showed that low ferulic acid concentrations (1-10mM) significantly increased (p ≤ 0.001) toxin production, regardless of the aw. High doses of ferulic acid (20-25 mM) reduced fumonisin production, in comparison with the controls, by both Fusarium species but they were not statistically significant in most cases. The results show that the use of ferulic acid as a post-harvest strategy to reduce mycotoxin accumulation on maize needs to be discussed.

  15. Effect of chloride ion on corrosion behavior of SUS316L-grade stainless steel in nitric acid solutions containing seawater components under γ-ray irradiation

    Science.gov (United States)

    Sano, Y.; Ambai, H.; Takeuchi, M.; Iijima, S.; Uchida, N.

    2017-09-01

    Concerning the Fukushima Daiichi nuclear power plant accident, we investigated the effect of chloride ion on the corrosion behavior of SUS316L stainless steel, which is a typical material for the equipment used in reprocessing, in HNO3 solution containing seawater components, including under γ-ray irradiation condition. Electrochemical and immersion tests were carried out using a mixture of HNO3 and artificial seawater (ASW). In the HNO3 solution containing high amounts of ASW, the cathodic current densities increased and uniform corrosion progressed. This might be caused by strong oxidants, such as Cl2 and NOCl, generated in the reaction between HNO3 and Cl- ions. The corrosion rate decreased with the immersion time at low concentrations of HNO3, while it increased at high concentrations. Under γ-ray irradiation condition, the corrosion rate decreased due to the suppression of the cathodic reactions by the reaction between the above oxidants and HNO2 generated by radiolysis.

  16. Effect of Gibberellic Acid and Choline Chloride on the Physiological Indices of Eucalyptu urophylla Seedlings%赤霉素和氯化胆碱对尾叶桉幼苗生理指标的影响

    Institute of Scientific and Technical Information of China (English)

    邓福春; 韦泳丽; 杨振德; 翟明普; 王美英

    2012-01-01

    [Objective] To explore the effects of physiological variations that the complex preparations, which were made up of the biological active fertilizers rich in trace elements and the gibberellic acid and choline chloride, on the growth of Eucalyptu urophylla. [ Method] Pot experiment was used in the paper to study changes of physiological indices of chlorophyll content, net photosynthetic rate, transpiration rate and so on of Eucalyptu urophylla seedlings caused by eight kinds of complex preparations, [ Result ] The effects caused by different treatments on the physiological indices of Eucalyptus urophylla seedling were different. General analyses showed that the treatment with 0.1 ml peptide, 30 mg choline chloride and 10 mg gibberellic acid as well as the treatment with 30 mg choline chloride and 10 mg gibberellic acid could obviously improve net photosynthetic rate, transpiration rate, stomatal conductance and water use efficiency of Eucalyptus urophylla seedlings. [ Conclusion] The gibberellic acid and choline chloride had a certain effects on the growth of Eucalyptu urophylla seedlings, therefore, plant growth regulators will have great potential to promote the growth of Eucalyptus and it is worthy of being further researched and developed.%[目的]探讨富含微量元素的生物活性肥添加赤霉素和氯化胆碱2种植物生长调节剂的复合制剂对尾叶桉幼苗生理的影响.[方法]采用8种药剂组合对盆栽尾叶按幼苗进行试验,研究其对尾叶桉幼苗叶绿素含量、净光合速率、蒸腾速率等生理指标的影响.[结果]不同的药剂组合对尾叶桉幼苗的生理影响效果不同.从总体上看,养生肽0.1ml+氯化胆碱30 mg+赤霉素10 mg和氯化胆碱30mg+赤霉素10 mg的处理能明显提高尾叶桉幼苗的净光合速率、蒸腾速率、气孔导度及水分利用效率.[结论]赤霉素和氯化胆碱对尾叶桉幼苗的生长具有一定的促进作用,植物生长调节剂在进

  17. Thallium extraction from hydrochloric acid media into a deep eutectic solvent using bis(2-ethylhexyl) phosphate

    Science.gov (United States)

    Tran, Kate; Volia, Merinda; Tereshatov, Evgeny; Folden, Charles, III

    2016-09-01

    The chemical properties of superheavy elements are relatively unknown due to their short half-lives and difficulty of production. In preparation for a future experiment to study the chemical properties of element 113, separation techniques have been used to study the behavior of its homologs, In and Tl. Previous work studied the liquid-liquid extraction of radioactive 201Tl (t1 / 2 = 3 . 04 d) from various concentrations of HCl into a mixture of menthol and lauric acid that formed a so-called deep eutectic solvent (DES). This work focuses on the effects of adding an extraction agent, bis(2-ethylhexyl) phosphate (HDEHP), to the DES on the efficiency of thallium extraction. The extraction of Tl(I) was generally poor, both with and without HDEHP added. In contrast, 111In (t1 / 2 = 2 . 80 d) showed significant extraction using HDEHP added to the same DES. This difference in behavior could potentially be exploited in a future experiment on the chemistry of element 113. National Science Foundation.

  18. Optimization of media for bioethanol production by Pichia stipitis from sugarcane bagasse pretreated by dilute acid

    Directory of Open Access Journals (Sweden)

    Mohsen Ahi

    2014-04-01

    Full Text Available Introduction: Reduction of fossil fuels due to its increasing consumption caused the biofuels production as an important topic, today. Using resources that have not food application was regarded as the second generation biofuels and consisted of lignocelluloses. Since considerable amount of lignocellulosic material are pentoses, utilizing them is important for the production of biofuels. Materials and methods: Sugarcane bagasse was pretreated with dilute acid method. Pichia stipitis was used for the fermentation of released sugars. A L27 Taguchi orthogonal array was considered to optimize the fermentation process and increase the amount of ethanol. The eight factors with three levels considering nitrogen, phosphorus, zinc, sulfur, magnesium, and vitamins sources were considered in this study. Results: The analysis of the results shows that corn steep liquor, ammonium hydrogen phosphate, potassium di-hydrogen phosphate and magnesium sulfate have a significant effect on the production of ethanol, respectively. Confirmation of the optimal conditions shows that ethanol production was increased 97% relative to the mean of the observed results. The yield and productivity during 48 h of the fermentation were reached to 0.26 (g ethanol/g consumed sugar and 0.125g (L.h, respectively. Discussion and conclusion: At the optimum condition the production of ethanol from sugarcane bagasse hydrolysate had higher efficiency relative to previous studies. Results of medium optimization considering cheap resources showed showed an excellent potential toward an economical bioethanol production process.

  19. Column experiments to investigate transport of colloidal humic acid through porous media during managed aquifer recharge

    Science.gov (United States)

    Liu, Dan; Zhou, Jingjing; Zhang, Wenjing; Huan, Ying; Yu, Xipeng; Li, Fulin; Chen, Xuequn

    2016-09-01

    Colloids act as vectors for pollutants in groundwater, thereby creating a series of environmental problems. While managed aquifer recharge plays an important role in protecting groundwater resources and controlling land subsidence, it has a significant effect on the transport of colloids. In this study, particle size and zeta potential of colloidal humic acid (HA) have been measured to determine the effects of different hydrochemistry conditions. Column experiments were conducted to examine the effects on the transport of colloidal HA under varying conditions of pH (5, 7, 9), ionic strength (<0.0005, 0.02, 0.05 M), cation valence (Na+, Ca2+) and flow rate (0.1, 0.2, 0.4 ml/min) through collectors (glass beads) to model the properties and quality of artificial recharge water and changes in the hydrodynamic field. Breakthrough curves showed that the behavior of colloidal HA being transported varied depending on the conditions. Colloid transport was strongly influenced by hydrochemical and hydrodynamic conditions. With decreasing pH or increasing ionic strength, a decrease in the peak effluent concentration of colloidal HA and increase in deposition could be clearly seen. Comparison of different cation valence tests indicated that changes in transport and deposition were more pronounced with divalent Ca2+ than with monovalent Na+. Changes in hydrodynamic field (flow rate) also had an impact on transportation of colloidal HA. The results of this study highlight the need for further research in this area.

  20. Organic compounds as corrosion inhibitors for mild steel in acidic media: correlation between inhibition efficiency and chemical structure

    Energy Technology Data Exchange (ETDEWEB)

    Elias, Elizandra C.S.; Chrisman, Erika C.A.N. [Universidade Federal do Rio de Janeiro (UFRJ), Rio de Janeiro, RJ (Brazil). Escola de Quimica

    2009-12-19

    The use of inhibitors for mild steels corrosion control which are in contact with aggressive environment is an accepted practice in acid treatment of oil-wells. Organic compounds have been studied to evaluate their corrosion inhibition potential. Film-forming corrosion inhibitors, commonly used to protect oil-field equipment, can be absorbed on the steel surface to give structurally ordered layers. Therefore, the electrons should act as an important role for this adsorption. Studies reveal that organic compounds show significant inhibition efficiency. For this purpose, their molecules should contain N, O and S heteroatoms in various functional groups, long hydrocarbon linear or branched radical and anion and cation active components. However, most of these compounds are not only expensive but also toxic to living beings. According to the 'Green Chemistry' rules, corrosion inhibitors based on organic compounds should be cheap, with low toxicity and have high inhibition efficiency. In this study, the effects of some organic compounds with different groups such as amide, ether, phenyldiamine, anime and aminophenol on the corrosion behavior of mild steel in acidic media have been investigated. The experimental data were obtained by gravimetric measurements. The results show that these compounds reveal a promising corrosion inhibition where phenyldiamine is the most efficient. The effect of molecular structure on the corrosion inhibition efficiency was investigated by semi-empirical quantum chemical calculations. The electronic properties such as highest occupied molecular orbital (HOMO), lowest unoccupied molecular orbital (LUMO) energy levels, and LUMO-HOMO energy gap orbital density were calculated. The relations between the inhibition efficiency and some quantum parameters are discussed and correlations are proposed. The highest values for the HOMO densities were found in the vicinity nitrogen atom, indicating that it is the most probable adsorption center

  1. Transport in Porous Media of Poly(Acrylic Acid) Coated Ferrihydrite Nanoparticles

    Science.gov (United States)

    Jaffe, P. R.; Xiang, A.; Koel, B. E.

    2012-12-01

    Augmentation of soils with iron to enhance biological processes such as uranium reduction via iron reducing bacteria, e.g., Geobacter sp., might be achieved via the injection of iron nanoparticles into the subsurface. The challenge is to make these nanoparticles transportable in the subsurface while not affecting the iron bioavailability. Poorly crystallized 2-line ferrihydrite iron oxide nanoparticles were synthesized and coated with different amounts of poly(acrylic acid) polymers (Na-PAA6K or Na-PAA140K). Analyses were then performed on these particles, including sorption/desorption of the polymer onto the iron nanoparticles, particle size, zeta potential, transport in sand and soil columns, and bioavailabity of the Fe(III) in the absence and presence of the coating to iron reducing organisms. Results showed that at pH values of environmental relevance, the zeta potential of the particles varied from about 3 mV (pH=8.2) for the non-coated particles to about -30 mV for the particles coated with the polymers to their highest sorption capacity. The coated particle diameter was shown to be in the range of 200 nm. Column transport experiments showed that for the highest polymer coating the nanoparticle breakthrough was virtually identical to that of bromide, while significant filtration was observed for particles with an intermediate coating, and complete particle removal via filtration was observed for the non-coated particles. These results held for sand as well as for soil, which had been previously characterized, from a field site at Rifle, CO. Bioavailability experiments showed no difference in the iron reduction rate between the untreated and treated nanoparticles. These results show that it is possible to manufacture iron nanoparticles to enhance biological iron reduction, and that the transport properties of these treated particles is tunable so that a desired retention in the porous medium can be achieved.

  2. Lithium Sulfuryl Chloride Battery.

    Science.gov (United States)

    Primary batteries , Electrochemistry, Ionic current, Electrolytes, Cathodes(Electrolytic cell), Anodes(Electrolytic cell), Thionyl chloride ...Phosphorus compounds, Electrical conductivity, Calibration, Solutions(Mixtures), Electrical resistance, Performance tests, Solvents, Lithium compounds

  3. Chloride channels in stroke

    Institute of Scientific and Technical Information of China (English)

    Ya-ping ZHANG; Hao ZHANG; Dayue Darrel DUAN

    2013-01-01

    Vascular remodeling of cerebral arterioles,including proliferation,migration,and apoptosis of vascular smooth muscle cells (VSMCs),is the major cause of changes in the cross-sectional area and diameter of the arteries and sudden interruption of blood flow or hemorrhage in the brain,ie,stroke.Accumulating evidence strongly supports an important role for chloride (Clˉ) channels in vascular remodeling and stroke.At least three Clˉ channel genes are expressed in VSMCs:1) the TMEM16A (or Ano1),which may encode the calcium-activated Clˉ channels (CACCs); 2) the CLC-3 Clˉ channel and Clˉ/H+ antiporter,which is closely related to the volume-regulated Clˉ channels (VRCCs); and 3) the cystic fibrosis transmembrane conductance regulator (CFTR),which encodes the PKA-and PKC-activated Clˉ channels.Activation of the CACCs by agonist-induced increase in intracellular Ca2+ causes membrane depolarization,vasoconstriction,and inhibition of VSMC proliferation.Activation of VRCCs by cell volume increase or membrane stretch promotes the production of reactive oxygen species,induces proliferation and inhibits apoptosis of VSMCs.Activation of CFTR inhibits oxidative stress and may prevent the development of hypertension.In addition,Clˉ current mediated by gammaaminobutyric acid (GABA) receptor has also been implicated a role in ischemic neuron death.This review focuses on the functional roles of Clˉ channels in the development of stroke and provides a perspective on the future directions for research and the potential to develop Clˉ channels as new targets for the prevention and treatment of stroke.

  4. Treasure of the Past VI: Standard Potential of the Silver-Silver-Chloride Electrode from 0° to 95° C and the Thermodynamic Properties of Dilute Hydrochloric Acid Solutions.

    Science.gov (United States)

    Bates, R G; Bower, V E

    2001-01-01

    From electromotive-force measurements of the cell without liquid junction: [Formula: see text]through the range 0° to 95° C, calculations have been made of (1) the standard potential of the silver-silver-chloride electrode, (2) the activity coefficient of hydrochloric acid in aqueous solutions from m (molality) =0 to m=0.1 and from 0° to 90° C, (3) the relative partial molal heat content of hydrochloric acid, and (4) the relative partial molal heat capacity of hydrochloric acid. The extrapolations were made by the method of least squares with the aid of punch-card techniques. Data from at least 24 cells were analyzed at each temperature, and 81 cells were studied at 25° C. The value of the standard potential was found to be 0.22234 absolute volt at 25° C, and the standard deviation was 0.02 millivolt at 0° C, 0.01 millivolt at 25° C, and 0.09 millivolt at 95° C. The results from 0° to 60° C are compared with earlier determinations of the standard potential and other quantities derived from the electromotive force.

  5. Preparation and Characteristics of Polyaluminium Chloride by Utilizing Fluorine-Containing Waste Acidic Mother Liquid from Clay-Brine Synthetic Cryolite Process

    Directory of Open Access Journals (Sweden)

    Feng-shan Zhou

    2014-01-01

    Full Text Available Clay-brine process employing activated clay, NaCl, HCl, and HF as raw materials is the primarily advanced technology to synthesize cryolite in the present industrial grade. However, plenty of byproducts of fluorine-containing waste HCl at the concentration of about 10%~12% could not be utilized comprehensively and are even hazardous to the environment. This work proposed a new two-step technology to prepare inorganic polymer flocculants polyaluminium chloride (PAC from synthetic cryolite mother liquor. Many specific factors such as the variety of aluminide source, reaction temperature and time, reagent ratio, and manner of alkaline addition were taken into consideration and their influences on the performances of produced PAC were discussed. It was found that synthetic cryolite mother liquor could react with bauxite and calcium aluminate directly to prepare cheap PAC, with plenty amount of water insoluble CaF2 and CaSiF6 produced as well. However, once HCl was introduced into synthetic cryolite mother liquor as well as by utilizing bauxite as aluminide source and sodium aluminate as adjusting basicity agent, the resultant PAC would dissolve out higher amount of aluminum while producing little amount of water insoluble materials. The coagulation behavior of the specially produced PAC could even match the industrial grade PAC conforming to national standard.

  6. Identification of Specific Effect of Chloride on the Spectral Properties and Structural Stability of Multiple Extracellular Glutamic Acid Mutants of Bacteriorhodopsin

    Science.gov (United States)

    Lazarova, Tzvetana; Mlynarczyk, Krzysztof; Querol, Enric; Tenchov, Boris; Filipek, Slawomir; Padrós, Esteve

    2016-01-01

    In the present work we combine spectroscopic, DSC and computational approaches to examine the multiple extracellular Glu mutants E204Q/E194Q, E204Q/E194Q/E9Q and E204Q/E194Q/E9Q/E74Q of bacteriorhodopsin by varying solvent ionic strength and composition. Absorption spectroscopy data reveal that the absorption maxima of multiple EC Glu mutants can be tuned by the chloride concentration in the solution. Visible Circular dichroism spectra imply that the specific binding of Cl- can modulate weakened exciton chromophore coupling and reestablish wild type-like bilobe spectral features of the mutants. The DSC data display reappearance of the reversible thermal transition, higher Tm of denaturation and an increase in the enthalpy of unfolding of the mutants in 1 M KCl solutions. Molecular dynamics simulations indicate high affinity binding of Cl- to Arg82 and to Gln204 and Gln194 residues in the mutants. Analysis of the experimental data suggests that simultaneous elimination of the negatively charged side chain of Glu194 and Glu204 is the major cause for mutants’ alterations. Specific Cl- binding efficiently coordinates distorted hydrogen bonding interactions of the EC region and reconstitutes the conformation and structure stability of mutated bR in WT-like fashion. PMID:27657718

  7. Amine and Titanium (IV Chloride, Boron (III Chloride or Zirconium (IV Chloride-Promoted Baylis-Hillman Reactions

    Directory of Open Access Journals (Sweden)

    Shi-Cong Cui

    2001-10-01

    Full Text Available The Baylis-Hillman reactions of various aryl aldehydes with methyl vinyl ketone at temperatures below -20oC using Lewis acids such as titanium (IV chloride, boron (III chloride or zirconium (IV chloride in the presence of a catalytic amount of selected amines used as a Lewis bases afford the chlorinated compounds 1 as the major product in very high yields. Acrylonitrile can also undergo the same reaction to give the corresponding chlorinated product in moderate yield. A plausible reaction mechanism is proposed. However, if the reaction was carried out at room temperature (ca. 20oC, then the Z-configuration of the elimination product 3, derived from 1, was formed as the major product.

  8. Excitotoxic death induced by released glutamate in depolarized primary cultures of mouse cerebellar granule cells is dependent on GABAA receptors and niflumic acid-sensitive chloride channels.

    Science.gov (United States)

    Babot, Zoila; Cristòfol, Rosa; Suñol, Cristina

    2005-01-01

    Excitotoxic neuronal death has been linked to neurological and neurodegenerative diseases. Several studies have sought to clarify the involvement of Cl(-) channels in neuronal excitotoxicity using either N-methyl-D-aspartic acid (NMDA) or alpha-amino-3-hydroxy-5-methylisoxazole-4-propionate/kainic acid agonists. In this work we induced excitotoxic death in primary cultures of cerebellar granule cells by means of endogenously released glutamate. Excitotoxicity was provoked by exposure to high extracellular K(+) concentrations ([K(+)](o)) for 5 min. Under these conditions, a Ca(2+)-dependent release of glutamate was evoked. When extracellular glutamate concentration rose to between 2 and 4 microM, cell viability was significantly reduced by 30-40%. The NMDA receptor antagonists (MK-801 and D-2-amino-5-phosphonopentanoic acid) prevented cell death. Exposure to high [K(+)](o) produced a (36)Cl(-) influx which was significantly reduced by picrotoxinin. In addition, the GABA(A) receptor antagonists (bicuculline, picrotoxinin and SR 95531) protected cells from high [K(+)](o)-triggered excitotoxicity and reduced extracellular glutamate concentration. The Cl(-) channel blockers niflumic acid and 5-nitro-2-(3-phenylpropylamino)benzoic acid also exerted a neuroprotective effect and reduced extracellular glutamate concentration, even though they did not reduce high [K(+)](o)-induced (36)Cl(-) influx. Primary cultures of cerebellar granule cells also contain a population of GABAergic neurons that released GABA in response to high [K(+)](o). Chronic treatment of primary cultures with kainic acid abolished GABA release and rendered granule cells insensitive to high [K(+)](o) exposure, even though NMDA receptors were functional. Altogether, these results demonstrate that, under conditions of membrane depolarization, low micromolar concentrations of extracellular glutamate might induce an excitotoxic process through both NMDA and GABA(A) receptors and niflumic acid-sensitive Cl

  9. Relaxation of endothelin-1-induced pulmonary arterial constriction by niflumic acid and NPPB: mechanism(s) independent of chloride channel block.

    Science.gov (United States)

    Kato, K; Evans, A M; Kozlowski, R Z

    1999-03-01

    We investigated the effects of the Cl- channel blockers niflumic acid, 5-nitro-2-(3-phenylpropylamino)-benzoic acid (NPPB) and 4, 4'-diisothiocyanatostilbene-2,2'-disulphonic acid (DIDS) on endothelin-1 (ET-1)-induced constriction of rat small pulmonary arteries (diameter 100-400 microm) in vitro, following endothelium removal. ET-1 (30 nM) induced a sustained constriction of rat pulmonary arteries in physiological salt solution. Arteries preconstricted with ET-1 were relaxed by niflumic acid (IC50: 35.8 microM) and NPPB (IC50: 21.1 microM) in a reversible and concentration-dependent manner. However, at concentrations known to block Ca++-activated Cl- channels, DIDS (acid (30 microM) and NPPB (30 microM) inhibited the ET-1-induced constriction by approximately 53% and approximately 60%, respectively, both in the continued presence of nifedipine and in Ca++-free physiological salt solution. The Ca++ ionophore A23187 (10 microM) also evoked a sustained constriction of pulmonary arteries. Surprisingly, the A23187-induced constriction was also inhibited in a reversible and concentration-dependent manner by niflumic acid (IC50: 18.0 microM) and NPPB (IC50: 8.8 microM), but not by DIDS (acid and NPPB inhibit pulmonary artery constriction is independent of Cl- channel blockade. One possibility is that these compounds may block the Ca++-dependent contractile processes.

  10. Removal of CdTe in acidic media by magnetic ion-exchange resin: A potential recycling methodology for cadmium telluride photovoltaic waste

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Teng, E-mail: zhangteng@mail.iee.ac.cn; Dong, Zebin; Qu, Fei; Ding, Fazhu; Peng, Xingyu; Wang, Hongyan; Gu, Hongwei

    2014-08-30

    Highlights: • Sulfonated magnetic microsphere was prepared as one strong acid cation-exchange resin. • Cd and Te can be removed directly from the highly acidic leaching solution of CdTe. • Good chemical stability, fast adsorbing rate and quick magnetic separation in strong acidic media. • A potential path for recycling CdTe photovoltaic waste. - Abstract: Sulfonated magnetic microspheres (PSt-DVB-SNa MPs) have been successfully prepared as adsorbents via an aqueous suspension polymerization of styrene-divinylbenzene and a sulfonation reaction successively. The resulting adsorbents were confirmed by means of Fourier transform infrared spectra (FT-IR), X-ray diffraction (XRD), transmission electron microscope (TEM), scanning electron microscope equipped with an energy dispersive spectrometer (SEM-EDS) and vibrating sample magnetometer (VSM). The leaching process of CdTe was optimized, and the removal efficiency of Cd and Te from the leaching solution was investigated. The adsorbents could directly remove all cations of Cd and Te from a highly acidic leaching solution of CdTe. The adsorption process for Cd and Te reached equilibrium in a few minutes and this process highly depended on the dosage of adsorbents and the affinity of sulfonate groups with cations. Because of its good adsorption capacity in strong acidic media, high adsorbing rate, and efficient magnetic separation from the solution, PSt-DVB-SNa MPs is expected to be an ideal material for the recycling of CdTe photovoltaic waste.

  11. Broadcasting behavior change: a comparison of the effectiveness of paid and unpaid media to increase folic acid awareness, knowledge, and consumption among Hispanic women of childbearing age.

    Science.gov (United States)

    Flores, Alina L; Prue, Christine E; Daniel, Katherine Lyon

    2007-04-01

    Awareness about folic acid's effectiveness in reducing the risk of certain birth defects has increased among women in the United States; however, few Hispanic women are consuming enough folic acid daily. A 1998 survey conducted by the Gallup Organization for the National March of Dimes Birth Defects Foundation found that English-speaking Hispanic women had lower folic acid awareness (53% vs. 72%) and lower daily consumption (29% vs. 33%) than non-Hispanic White women. In 1999, the Centers for Disease Control and Prevention (CDC) conducted baseline surveys with Spanish-speaking Hispanic women in selected U.S. markets to measure folic acid awareness, knowledge, and consumption. A Spanish-language public service announcement (PSA) volunteer campaign and a paid Spanish-language media and community education campaign were conducted in 2000 and 2002, respectively. Comparisons of postcampaign surveys indicate that the paid media campaign was significantly more effective than the PSA campaign in increasing folic acid awareness, knowledge, and consumption among Spanish-speaking Hispanic women.

  12. Mass concentration and ion composition of coarse and fine particles in an urban area in Beirut: effect of calcium carbonate on the absorption of nitric and sulfuric acids and the depletion of chloride

    Directory of Open Access Journals (Sweden)

    H. Kouyoumdjian

    2006-01-01

    Full Text Available Levels of coarse (PM10-2.5 and fine (PM2.5 particles were determined between February 2004 and January 2005 in the city of Beirut, Lebanon. While low PM mass concentrations were measured in the rainy season, elevated levels were detected during sand storms originating from Arabian desert and/or Africa. Using ATR-FTIR and IC, it was shown that nitrate, sulfate, carbonate and chloride were the main anionic constituents of the coarse particles, whereas sulfate was mostly predominant in the fine particles in the form of (NH42SO4. Ammonium nitrate was not expected to be important because the medium was defined as ammonium poor. In parallel, the cations Ca2+ and Na+ dominated in the coarse, and NH4+, Ca2+ and Na+ in the fine particles. Coarse nitrate and sulfate ions resulted from the respective reactions of nitric and sulfuric acid with a relatively high amount of calcium carbonate. Both CaCO3 and Ca(NO32 crystals identified by ATR-FTIR in the coarse particles were found to be resistant to soaking in water for 24 h but became water soluble when they were formed in the fine particles suggesting, thereby, different growth and adsorption phenomena. The seasonal variational study showed that nitrate and sulfate ion concentrations increased in the summer due to the enhancement of photochemical reactions which facilitated the conversion of NO2 and SO2 gases into NO3- and SO42-, respectively. While nitrate was mainly due to local heavy traffic, sulfates were due to local and long-range transport phenomena. Using the air mass trajectory HYSPLIT model, it was found that the increase in the sulfate concentration correlated with wind vectors coming from Eastern and Central Europe. Chloride levels, on the other hand, were high when wind originated from the sea and low during sand storms. In addition to sea salt, elevated levels of chloride were also attributed to waste mass burning in proximity to the site. In comparison to other neighboring Mediterranean

  13. Chloride channels of platelets%血小板氯通道

    Institute of Scientific and Technical Information of China (English)

    陈晓琳; 尹松梅

    2004-01-01

    Chloride channels distribute widely in the body, and participate in many physiological actions and regulatory processes. Based on their physiological roles and molecular structures, six kinds of chloride channels have been identified: (1) The chloride channels family; (2) Cystic fibrosis transmembrane conductance regulator; (3) Swelling-activated chloride channels; (4) Calcium-activated chloride channels; (5) The p64 (CLIC) gene family; (6) γ-aminobutyric acid and glycine receptors. The chloride channels do exist in platelets, and their appearances are dependent on the presence of intracellular calcium. Blocking agents of chloride channels inhibit the thrombin-activated platelet aggregation and the elevation of the intracellular calcium concentration in a dose-dependent manner. It is suggested that chloride channels play a role in the activation of platelets. In addition, chloride channels act on both the cell volume regulation and the intracellular pH regulation in platelets.

  14. Whole Blood ω-3 Fatty Acids Are Inversely Associated with Carotid Intima-Media Thickness in Indigenous Mexican Women.

    Science.gov (United States)

    Monge, Adriana; Harris, William S; Ortiz-Panozo, Eduardo; Yunes, Elsa; Cantu-Brito, Carlos; Catzin-Kuhlmann, Andres; López-Ridaura, Ruy; Lajous, Martín

    2016-07-01

    Long-chain ω-3 (n-3) polyunsaturated fatty acids (PUFAs) may reduce the risk of atherosclerosis. The association between n-3 PUFAs and cardiovascular disease may vary across different populations, and there is limited information on Hispanic individuals with mixed Amerindian and European origin. We evaluated the cross-sectional relations between whole blood n-3 PUFAs and carotid intima-media thickness (IMT) in Mexican women living in Mexico and assessed whether this relation was different in women who spoke an indigenous language compared with women who did not. In 2012-2013, we assessed the association between blood n-3 PUFAs and IMT in 1306 women free of disease in Chiapas and Yucatan, Mexico. We categorized blood n-3 PUFAs (% of total FAs) in quartiles and adjusted linear regression models by age, indigenous language, site, socioeconomic status, education, smoking, menopause, diabetes, hypertension, hypercholesterolemia, body mass index, physical activity, and diet. We stratified analyses by indigenous/nonindigenous language speakers (n = 315 of 991). Whole blood n-3 PUFAs (means ± SDs) were 3.58% ± 0.78% of total FAs. We did not observe a significant association between n-3 PUFAs and IMT in the overall study population. However, the adjusted mean difference of IMT was -6.5% (95% CI: -10.7%, -2.3%; P-trend indigenous women in the highest quartile compared with the lowest quartile of blood n-3 PUFAs. In nonindigenous women, we did not observe an association (-0.6%; 95% CI: -3.0%, 1.8%, comparing extreme quartiles; P-trend = 1.00). Overall, circulating n-3 PUFAs were not associated with IMT. However, we observed a strong statistically significant inverse association with IMT in indigenous Mexican women. Future studies should evaluate genetic markers that may reflect differences in n-3 PUFA metabolism across populations. © 2016 American Society for Nutrition.

  15. Controlling chloride ions diffusion in concrete.

    Science.gov (United States)

    Zeng, Lunwu; Song, Runxia

    2013-11-28

    The corrosion of steel in concrete is mainly due to the chemical reaction between the chloride ions and iron ions. Indeed, this is a serious threaten for reinforced concrete structure, especially for the reinforced concrete structure in the sea. So it is urgent and important to protect concrete against chloride ions corrosion. In this work, we report multilayer concrete can cloak chloride ions. We formulated five kinds of concrete A, B, C, D and E, which are made of different proportion of cement, sand and glue, and fabricated six-layer (ABACAD) cylinder diffusion cloak and background media E. The simulation results show that the six-layer mass diffusion cloak can protect concrete against chloride ions penetration, while the experiment results show that the concentration gradients are parallel and equal outside the outer circle in the diffusion flux lines, the iso-concentration lines are parallel outside the outer circle, and the concentration gradients in the inner circle are smaller than those outside the outer circle.

  16. Controlling chloride ions diffusion in concrete

    Science.gov (United States)

    Zeng, Lunwu; Song, Runxia

    2013-11-01

    The corrosion of steel in concrete is mainly due to the chemical reaction between the chloride ions and iron ions. Indeed, this is a serious threaten for reinforced concrete structure, especially for the reinforced concrete structure in the sea. So it is urgent and important to protect concrete against chloride ions corrosion. In this work, we report multilayer concrete can cloak chloride ions. We formulated five kinds of concrete A, B, C, D and E, which are made of different proportion of cement, sand and glue, and fabricated six-layer (ABACAD) cylinder diffusion cloak and background media E. The simulation results show that the six-layer mass diffusion cloak can protect concrete against chloride ions penetration, while the experiment results show that the concentration gradients are parallel and equal outside the outer circle in the diffusion flux lines, the iso-concentration lines are parallel outside the outer circle, and the concentration gradients in the inner circle are smaller than those outside the outer circle.

  17. 氯化胆碱/草酸型低共熔溶剂氧化脱除模拟油硫化物%Oxidative desulfurization of model oil with choline chloride/oxalic acid as a eutectic solvent

    Institute of Scientific and Technical Information of China (English)

    李佳慧; 胡嘉; 赵荣祥; 乔海燕; 李秀萍

    2014-01-01

    通过氯化胆碱和草酸在100℃下搅拌,合成了氯化胆碱/草酸型低共熔溶剂。以氯化胆碱/草酸为催化剂、过氧化氢为氧化剂、咪唑氟硼酸盐离子液体为萃取剂氧化萃取一体法脱除模拟油中的二苯并噻吩(DBT)。考察了反应温度、反应时间、氧化剂加入量、萃取剂类型、硫化物类型等因素对脱硫效率的影响。结果表明,当以咪唑氟硼酸盐为萃取剂,n(H2 O2)/n(S)=8、反应温度30℃、反应80 min 时,二苯并噻吩的脱除率可以达到95%。催化剂重复使用5次后,脱硫率仍然保持在90%。%Choline chloride / oxalic acid as a eutectic solvent was synthesized by the reaction of choline chloridewith oxalic acid at 100 ℃ via simple stirring. The removal of dibenzothiophene (DBT) in model oil was carried out by using choline chloride / oxalic acid as a catalyst, hydrogen peroxide as oxidant, imidazoliumtetrafluoroborate ionic liquid as extractant; the influence of reaction temperature and time, the amount of hydrogen peroxide, the type of extractant, the type of sulfur-containing compound ( thiophene and itshomologues ) on the desulfurization efficiency were investigated. The results indicated that under the optimal reaction conditions of n ( H2 O2 ) / n ( S ) = 8, reaction temperature of 30 ℃ and time of 80 min, thedesulfurization efficiency for DBT reaches without a significant decrease in the desulfurization activity. 95% . Moreover, the reaction system can be recycled for 5 times.

  18. D2EHPA对高浓度盐酸介质中钛的萃取%Solvent extraction of tetravalent thitanium from high concentration of acidic chloride solutions by D2EHPA

    Institute of Scientific and Technical Information of China (English)

    毛雪华; 刘代俊

    2012-01-01

    研究了D2 EHPA对盐酸介质中钛的萃取和反萃性能.研究结果表明:萃取液中钛以TiOCl2·2 D2 EHPA的形式存在.钛萃取率随无机相中氯离子浓度和有机相中萃取剂浓度的增加而增加.D2EHPA对钛的饱和承载量为8.98 g/100 g D2EHPA.红外光谱研究进一步表明了Ti-D2EHPA螯合物的性质.在0.5-12 moL/dm3的盐酸介质中,D2EHPA对钛的萃取率随盐酸介质浓度的增加而增加,而对铁、铝、钙、镁无萃取性能.以7% H2O2 +3 mol/dm3 H2SO4为反萃剂,有机相中的钛可实现一次完全反萃.%The solvent extraction and stripping of titanium(IV) from acidic chloride solutions by D2EHPA(di-2-ethylhexyl phosphoric acid) in kerosene has been investigated. The solvent extraction results show that the dissolved titanium is present as TiOCl2 ·D2EHPA. The extractability of titanium ( IV ) increases with the increase of the total chloride concentration in the aqueous phase and the extractant concentration in the organic phase. The loading capacity of D2EHPA for titanium( IV) is 8. 98 g/100 g D2EHPA. IR spectroscopy is used to study the extracted complex in order to further clarify the nature of extracted complex. The results show that,the extractability of titanium( IV) increases when the concentration of hydrochloric acid aqueous solution increases from 0.5 mol'dm" to 12 mol o dm . On the other hand, iron ( III) , aluminum ( HI) , calcium ( II ) and magnesium ( II ) are not extracted under the same experimental conditions. Titanium( IV) can be completely stripped from the metal loaded organic phase with 7% H2O2 in 3 mol-dm H2SO4 as the stripping agent.

  19. Association of branched-chain amino acids with carotid intima-media thickness and coronary artery disease risk factors.

    Directory of Open Access Journals (Sweden)

    Ruiyue Yang

    Full Text Available BACKGROUND: Recent studies have determined that branched-chain (BCAAs and aromatic (AAAs amino acids are strongly correlated with obesity and atherogenic dyslipidemia and are strong predictors of diabetes. However, it is not clear if these amino acids are capable of identifying subjects with coronary artery disease (CAD, particularly with subclinical atherosclerosis who are at risk of developing CAD. METHODS: Four hundred and seventy two Chinese subjects (272 males and 200 females, 42-97 y of age undergoing physical exams were recruited at random for participation in the cross-sectional study. Serum BCAAs and AAAs were measured using our previously reported isotope dilution liquid chromatography tandem mass spectrometry method. Bilateral B-mode carotid artery images for carotid intima-media thickness (cIMT were acquired at end diastole and cIMT values more than 0.9 mm were categorized as increased. Correlations of BCAAs with cIMT and other CAD risk factors were analyzed. RESULTS: BCAAs and AAAs were significantly and positively associated with risk factors of CAD, e.g., cIMT, BMI, waist circumference, blood pressure, fasting blood glucose, TG, apoB, apoB/apoAI ratio, apoCII, apoCIII and hsCRP, and were significantly and negatively associated with HDL-C and apoAI. Stepwise multiple linear regression analysis revealed that age (β = 0.175, P<0.001, log BCAA (β = 0.147, P<0.001 and systolic blood pressure (β = 0.141, P = 0.012 were positively and independently associated with cIMT. In the logistic regression model, the most and only powerful laboratory factor correlated with increased cIMT was BCAA (the odds ratio of the fourth quartile compared to the first quartile was 2.679; P = 0.009. CONCLUSION: BCAAs are independently correlated with increased cIMT. This correlation would open a new field of research in the mechanistic understanding and risk assessment of CAD.

  20. THE ROLE OF CHLORIDE ANION AND CFTR IN KILLING OF PSEUDOMONAS AERUGINOSA BY NORMAL AND CF NEUTROPHILS

    OpenAIRE

    Richard G. Painter; Bonvillain, Ryan W.; Vincent G Valentine; Lombard, Gisele A.; LaPlace, Stephanie G.; Nauseef, William M.; Wang, Guoshun

    2008-01-01

    Chloride anion is essential for myeloperoxidase to produce hypochlorous acid (HOCl) in neutrophils (PMNs). To define whether chloride availability to PMNs affects their HOCl production and microbicidal capacity, we examined how extracellular chloride concentration affects killing of Pseudomonas aeruginosa (PsA) by normal neutrophils. PMN-mediated bacterial killing was strongly dependent on extracellular chloride concentration. Neutrophils in a chloride-deficient medium killed PsA poorly. Howe...

  1. A Facile, Choline Chloride/Urea Catalyzed Solid Phase Synthesis of Coumarins via Knoevenagel Condensation

    National Research Council Canada - National Science Library

    Hosanagara N Harishkumar; Kittappa M Mahadevan; Hittalumane C Kiran Kumar; Nayak D Satyanarayan

    2011-01-01

    .... The active methylene compounds such as meldrum's acid, diethylmalonate, ethyl cyanoacetate, dimethylmalonate, were efficiently condensed with various salicylaldehydes in presence of choline chloride...

  2. Influence of sodium chloride and pH during acidic marination on water retention and mechanical properties of turkey breast meat.

    Science.gov (United States)

    Goli, T; Ricci, J; Bohuon, P; Marchesseau, S; Collignan, A

    2014-03-01

    Turkey breast cubes underwent acidic marination in the presence of salt. The transfer of water, salt and acid was measured, and texture was assessed on the cooked meat. While significant mass gains were observed during marination, from 20 minutes of immersion onwards, only long durations produced an overall matter balance greater than that of non-marinated meat. From the first minutes of immersion, these transfers caused hardening, regardless of the presence of salt in the marinade. For longer durations, only in the absence of salt was significant tenderizing seen in comparison to the non-marinated control. This effect appears to be due on the one hand to passing the isoelectric pH of the meat during acidification, and on the other hand to setting up antagonistic mechanisms breaking down or reinforcing connective tissues by acid and salt respectively. The high degree of tenderization observed in a water-acid solution can be explained partly by dilution of the fiber load per section unit due to protein solubilization.

  3. Chloride equilibrium potential in salamander cones

    Directory of Open Access Journals (Sweden)

    Bryson Eric J

    2004-12-01

    Full Text Available Abstract Background GABAergic inhibition and effects of intracellular chloride ions on calcium channel activity have been proposed to regulate neurotransmission from photoreceptors. To assess the impact of these and other chloride-dependent mechanisms on release from cones, the chloride equilibrium potential (ECl was determined in red-sensitive, large single cones from the tiger salamander retinal slice. Results Whole cell recordings were done using gramicidin perforated patch techniques to maintain endogenous Cl- levels. Membrane potentials were corrected for liquid junction potentials. Cone resting potentials were found to average -46 mV. To measure ECl, we applied long depolarizing steps to activate the calcium-activated chloride current (ICl(Ca and then determined the reversal potential for the current component that was inhibited by the Cl- channel blocker, niflumic acid. With this method, ECl was found to average -46 mV. In a complementary approach, we used a Cl-sensitive dye, MEQ, to measure the Cl- flux produced by depolarization with elevated concentrations of K+. The membrane potentials produced by the various high K+ solutions were measured in separate current clamp experiments. Consistent with electrophysiological experiments, MEQ fluorescence measurements indicated that ECl was below -36 mV. Conclusions The results of this study indicate that ECl is close to the dark resting potential. This will minimize the impact of chloride-dependent presynaptic mechanisms in cone terminals involving GABAa receptors, glutamate transporters and ICl(Ca.

  4. Chloride binding site of neurotransmitter sodium symporters.

    Science.gov (United States)

    Kantcheva, Adriana K; Quick, Matthias; Shi, Lei; Winther, Anne-Marie Lund; Stolzenberg, Sebastian; Weinstein, Harel; Javitch, Jonathan A; Nissen, Poul

    2013-05-21

    Neurotransmitter:sodium symporters (NSSs) play a critical role in signaling by reuptake of neurotransmitters. Eukaryotic NSSs are chloride-dependent, whereas prokaryotic NSS homologs like LeuT are chloride-independent but contain an acidic residue (Glu290 in LeuT) at a site where eukaryotic NSSs have a serine. The LeuT-E290S mutant displays chloride-dependent activity. We show that, in LeuT-E290S cocrystallized with bromide or chloride, the anion is coordinated by side chain hydroxyls from Tyr47, Ser290, and Thr254 and the side chain amide of Gln250. The bound anion and the nearby sodium ion in the Na1 site organize a connection between their coordinating residues and the extracellular gate of LeuT through a continuous H-bond network. The specific insights from the structures, combined with results from substrate binding studies and molecular dynamics simulations, reveal an anion-dependent occlusion mechanism for NSS and shed light on the functional role of chloride binding.

  5. Electrodeposition of copper on a Pt(111) electrode in sulfuric acid containing poly(ethylene glycol) and chloride ions as probed by in situ STM.

    Science.gov (United States)

    Fu, YunLin; Pao, Te; Chen, Sih-Zih; Yau, ShuehLin; Dow, Wei-Ping; Lee, Yuh-Lang

    2012-07-03

    This study employed real-time in situ STM imaging to examine the adsorption of PEG molecules on Pt(111) modified by a monolayer of copper adatoms and the subsequent bulk Cu deposition in 1 M H(2)SO(4) + 1 mM CuSO(4)+ 1 mM KCl + 88 μM PEG. At the end of Cu underpotential deposition (~0.35 V vs Ag/AgCl), a highly ordered Pt(111)-(√3 × √7)-Cu + HSO(4)(-) structure was observed in 1 M H(2)SO(4) + 1 mM CuSO(4). This adlattice restructured upon the introduction of poly(ethylene glycol) (PEG, molecular weight 200) and chloride anions. At the onset potential for bulk Cu deposition (~0 V), a Pt(111)-(√3 × √3)R30°-Cu + Cl(-) structure was imaged with a tunneling current of 0.5 nA and a bias voltage of 100 mV. Lowering the tunneling current to 0.2 nA yielded a (4 × 4) structure, presumably because of adsorbed PEG200 molecules. The subsequent nucleation and deposition processes of Cu in solution containing PEG and Cl(-) were examined, revealing the nucleation of 2- to 3-nm-wide CuCl clusters on an atomically smooth Pt(111) surface at overpotentials of less than 50 mV. With larger overpotential (η > 150 mV), Cu deposition seemed to bypass the production of CuCl species, leading to layered Cu deposition, starting preferentially at step defects, followed by lateral growth to cover the entire Pt electrode surface. These processes were observed with both PEG200 and 4000, although the former tended to produce more CuCl nanoclusters. Raising [H(2)SO(4)] to 1 M substantiates the suppressing effect of PEG on Cu deposition. This STM study provided atomic- or molecular-level insight into the effect of PEG additives on the deposition of Cu.

  6. Effectiveness of the bran media and bacteria inoculum treatments in increasing pH and reducing sulfur-total of acid sulfate soils

    Science.gov (United States)

    Taufieq, Nur Anny Suryaningsih; Rahim, Sahibin Abdul; Jamil, Habibah

    2013-11-01

    This study was carried out to determine the effectiveness ofsulfate reducing bacteria (SRB) in using bran as a source of food and energy, and to see the effectiveness of the bran media and bacteria inoculums treatments for pH and sulfur-total of acid sulfate reduction insoils. This study used two factors in group random designs with four treatments for bacteria inoculum of B1 (1%), B2 (5%), B3 (10%), B4 (15%) and two treatments for organic media (bran) of D1 (1:1) and D2 (1:19). Based on three replications, the combination resulted in a total of 24 treatments. Soil pH was measured using the Duddridge and Wainright method and determination of sulfate content in soil was conducted by the spectrophotometry method. The data obtained was analyzed for significance by Analysis of Variance and the Least Significant Difference Test. The pH of the initial acid sulfate soils ranged from 3 to 4 and the soil sulfur-total ranged from 1.4% to 10%. After mixing sulfate reducing bacteria with the bran mediaand incubated for four days, the pH of the acid sulfate soils increased from 3.67 to 4.20, while the soil sulfur-total contents had been reduced by 2.85% to 0.35%. This experiment has proven that an acid sulfate soil with low pH is a good growth medium for the sulfate reducing bacteria. The bestincubation period to achieve an effective bioremediation resultthrough sulfate percentage reduction by sulfate reducing bacteria was 10 days, while the optimum bran media dose was 1:19, and the bacteria inoculums dose was 10%.

  7. chloride mass balance

    African Journals Online (AJOL)

    Agadaga

    1Geology Department, Faculty of Sciences and Techniques, University ... characterization of groundwater, rainfall and the unsaturated zone were also carried out using a .... 2008 in collaboration with the Senegal National Meteorological .... [Cl]sm is estimated as average chloride concentration in ..... sands of Australia.

  8. Chloride ingress prediction

    DEFF Research Database (Denmark)

    Frederiksen, Jens Mejer; Geiker, Mette Rica

    2008-01-01

    and time, and where both the surface chloride concentration and the diffusion coefficient are allowed to vary in time; the Mejlbro-Poulsen model is the general solution to Fick’s 2nd law. The paper also presents conversion formulas for the four decisive but rather abstract parameters to parameters, which...

  9. Isolation, characterization, and ecology of sulfur-respiring crenarchaea inhabiting acid-sulfate-chloride-containing geothermal springs in Yellowstone National Park.

    Science.gov (United States)

    Boyd, Eric S; Jackson, Robert A; Encarnacion, Gem; Zahn, James A; Beard, Trevor; Leavitt, William D; Pi, Yundan; Zhang, Chuanlun L; Pearson, Ann; Geesey, Gill G

    2007-10-01

    Elemental sulfur (S(0)) is associated with many geochemically diverse hot springs, yet little is known about the phylogeny, physiology, and ecology of the organisms involved in its cycling. Here we report the isolation, characterization, and ecology of two novel, S(0)-reducing Crenarchaea from an acid geothermal spring referred to as Dragon Spring. Isolate 18U65 grows optimally at 70 to 72 degrees C and at pH 2.5 to 3.0, while isolate 18D70 grows optimally at 81 degrees C and pH 3.0. Both isolates are chemoorganotrophs, dependent on complex peptide-containing carbon sources, S(0), and anaerobic conditions for respiration-dependent growth. Glycerol dialkyl glycerol tetraethers (GDGTs) containing four to six cyclopentyl rings were present in the lipid fraction of isolates 18U65 and 18D70. Physiological characterization suggests that the isolates are adapted to the physicochemical conditions of Dragon Spring and can utilize the natural organic matter in the spring as a carbon and energy source. Quantitative PCR analysis of 16S rRNA genes associated with the S(0) flocs recovered from several acid geothermal springs using isolate-specific primers indicates that these two populations together represent 17 to 37% of the floc-associated DNA. The physiological characteristics of isolates 18U65 and 18D70 are consistent with their potential widespread distribution and putative role in the cycling of sulfur in acid geothermal springs throughout the Yellowstone National Park geothermal complex. Based on phenotypic and genetic characterization, the designations Caldisphaera draconis sp. nov. and Acidilobus sulfurireducens sp. nov. are proposed for isolates 18U65 and 18D70, respectively.

  10. Effect of foliar calcium chloride treatment on the level of chlorogenic acid, β-carotene, lutein and tocopherols in lettuce (Lactuca sativa L.

    Directory of Open Access Journals (Sweden)

    Irena Perucka

    2012-12-01

    Full Text Available The aim of the presented study was to determine the effect of foliar application of CaCl2 on the level of β-carotene, lutein, tocopherols and phenolic compounds in the leaves of lettuce cv. Omega (Lactuca sativa L.. The experiments were conducted in the greenhouse of the Faculty of Cultivation and Fertilisation of Horticultural Plants, University of Life Sciences in Lublin. During the growing period, 7 and 14 days before harvest, the plants were treated with a solution of CaCl2 with concentrations of 0.1 M and 0.2 M. Plants sprayed with water were the control treatment in the experiment. Analyses were performed on whole leaves and the blade without midrib. The obtained results indicate that the leaves of lettuce cv. Omega are a good source of phenolic compounds, carotenoids and tocopherols. The dominant carotenoid in lettuce cv. Omega was β-carotene. Foliar application of CaCl2 on the plants did not have any significant effect on the level of β-carotene and lutein in the whole leaves. The contents of tocopherols, total phenolic compounds and chlorogenic acid were dependent on the concentration of CaCl2. The application of 0.1 M CaCl2 solution in the plants resulted in a decrease in the level of total phenolic compounds and chlorogenic acid, and an increase in tocopherol content. However, the treatment of the plants with 0.2M CaCl2 solution caused a lowering of the concentration of tocopherols and an increase in the content of chlorogenic acid and total phenolic compounds.

  11. Effect of PUFAs from Pteleopsis suberosa stem bark on androgenic enzymes, cellular ATP and prostatic acid phosphatase in mercury chloride – Exposed rat

    Directory of Open Access Journals (Sweden)

    J.K. Akintunde

    2017-09-01

    Full Text Available Occupational and environmental exposure to mercury causes varieties of adverse reproductive disorders in mammals. The present study was designed to investigate the unsaturated fatty acids of Pteleopsis suberosa stem bark extract (PTSSBE, evaluate its antioxidant properties and examine its biochemical targets on sub-acute mercury-induced testicular dysfunctions. Rats were divided into five groups of 10 animals each. Group I was given distilled water; group II, III, IV and V was orally administered with mercury at a dose of 3.75 mg/kg body weight. Group III, IV and V were co-treated with PTSSBE of 25, 50 and 100 mg/kg body weight respectively, for 10 days. Rats exposed to mercury significantly decreased the activities of catalase (CAT, lactate dehydrogenase (LDH, and the level of reduced glutathione (GSH, while the formation of malondialdehyde (MDA was increased. There was also a marked significant decrease (p < 0.05 in testicular activities of Δ5-3β-hydroxysteroid dehydrogenase and Δ5 17β-hydroxysteroid dehydrogenase. Moreover, the activities of prostatic acid phosphatase, total acid phosphatase and prostatic alkaline phosphatase, were significantly (p < 0.05 elevated in mercury treated rats. These effects were prevented by co-treatment with PTSSBE in mercury-induced testicular toxicity in rats. Aphrosidiac effects of Pteleopsis suberosa, may find clinical application in reproductive abnormalities. Isolation and translation of individual active ingredient would help to find new drugs to cure and/or prevent male infertility among mercury exposed workers.

  12. Resistance of different materials used in sewers systems:Polyvinyl chloride (PVC, polypropylene (PP and High density polyethylene (HDPE, to sulfuric acid and sodium sulfate attack.

    Directory of Open Access Journals (Sweden)

    LASFAR Sara

    2014-02-01

    Full Text Available The behaviour of PVC, PP and HDPE used in sewer systems exposed to acid and sulfate solutions was investigated at 25°C and 40°C. Gravimetric characterization proves that PVC has a fickian behavior. It shows also, that PP has a non-fickian behavior, characterized by a rapid acceleration of water absorption, and the HDPE has a fickian behavior at 25°C, while it has a non-fickian behavior at 40°C, characterized by a weight loss after a certain aging period. The prolongation of the time of exposure to sulfuric acid solution leads to a progressive increase in tensile strength followed by a slight decrease at 40°C. The unaged samples of all materials have a much lower tensile strength than those of the aged samples, and a drop in elongation at break could be observed. These results can be explained by the increase of crystallinity, followed by the increase of crosslinking density due to the diffusion of the solvent and the effect of the temperature as the exposure time increases. These results prove that there is a correlation between the diffusion of the solvent as well as the increased exposure time and temperature on the mechanical properties of polymer.

  13. Spectrophotometric determination of acidity constants of 2-(2-Thiazolylazo)-Cresol in various water-organic solvent media mixtures using chemometrics methods.

    Science.gov (United States)

    Momeni-Isfahani, Tahereh; Niazi, Ali

    2014-01-01

    The combination of soft- and hard-modeling was used to the spectrophotometric studies of the acidity constants of 2-(2-Thiazolylazo)-Cresol (TAC) at 25°C and at ionic strength 0.1 mol L(-1) in pure water as well as in aqueous media containing variable percentages (10-50%) of organic solvents. The organic solvents used were methanol, ethanol, dimethyl formamide (DMF) and 1,4-dioxane. The acidity constants of all related equilibria are estimated using the whole spectral fitting of the collected data to an established factor analysis model. DATAN program was applied for determining acidity constants and pure spectra of different form of TAC. Results show that the acidity constants of TAC are influenced as the percentages of solvents added to the solution. The corresponding pKa values in solvent-water mixtures were determined. There are linear relationships between acidity constants and the mole fraction of organic solvents in the solvent mixtures. The effects of various solvents on absorption properties and acidity constants of each component are also discussed. Copyright © 2013 Elsevier B.V. All rights reserved.

  14. Ionic conductivity and diffusion coefficient of barium-chloride-based polymer electrolyte with poly(vinyl alcohol)–poly(4-styrenesulphonic acid) polymer complex

    Indian Academy of Sciences (India)

    MAYANK PANDEY; GIRISH M JOSHI; NARENDRA NATH GHOSH

    2017-08-01

    A composite polymer electrolyte comprising poly(vinyl alcohol)–poly(4-styrenesulphonic acid) with bariumchloride dihydrate (BaCl$_2$·2H$_2$O) salt complex has been synthesized following the usual solution casting. The ionic conductivity of polymer electrolyte was analysed by impedance spectroscopy. The highest room temperature (at 30$^{\\circ}$C) conductivity evaluated was 9.38 $\\times$ 10$^{−6}$ S cm$^{−1}$ for 20 wt% loading of BaCl$_2$ in the polymer electrolyte. This has been referred to as the optimum conducting composition. The temperature-dependent ionic conductivity of the polymer electrolyte exhibits the Arrhenius relationship, which represents the hopping of ions in polymer composites. Cation and anion diffusion coefficients are evaluated using the Trukhan model. The transference number and enhanced conductivity imply that the charge transportation is due to ions. Therefore this polymer electrolyte can be further studied for the development of electrochemical device applications.

  15. A Palladium Catalyst System for the Efficient Cross-Coupling Reaction of Aryl Bromides and Chlorides with Phenylboronic Acid: Synthesis and Biological Activity Evaluation

    Directory of Open Access Journals (Sweden)

    Boubakri Lamia

    2017-03-01

    Full Text Available New benzimidazolium salts 1a–c and their palladium bis-N-heterocyclic carbene complexes 2a–c and palladium PEPPSI-type complexes 3a–c were designed, synthesized and structurally characterized by NMR (1H and 13C, IR, DART-TOF mass spectrometry and elemental analysis. Then these complexes 2–3 were employed in the Suzuki-Miyaura cross-coupling reaction of substituted arenes with phenylboronic acid under mild conditions in toluene and DMF/H2O (1/1 to afford functionalized biaryl derivatives in good to excellent yields. The antibacterial activity of palladium bis-N-heterocyclic carbene complexes 2a–c and palladium PEPPSI-type complexes 3a–c was measured by disc diffusion method against Gram positive and Gram negative bacteria. Compounds 2a, 2c and 3a–c exhibited potential antibacterial activity against four bacterial species among the five used indicator cells. The product 2b inhibits the growth of the all five tested microorganisms. Moreover, the antioxidant activity determination of these complexes 2–3, using 2.2-diphenyl-1-picrylhydrazyl (DPPH as a reagent, showed that compounds 2a–c and 3b possess DPPH antiradical activity. The higher antioxidant activity was obtained from the product 2b which has radical scavenging activity comparable to that of the two used positive controls (gallic acid “GA“ and tutylatedhydroxytoluene “BHT“. Investigation of the anti-acetylcholinesterase activity of the studied complexes showed that compounds 2b, 3a, and 3b exhibited moderate activity at 100 μg/mL and product 2b is the most active.

  16. A Palladium Catalyst System for the Efficient Cross-Coupling Reaction of Aryl Bromides and Chlorides with Phenylboronic Acid: Synthesis and Biological Activity Evaluation.

    Science.gov (United States)

    Lamia, Boubakri; Chakchouk-Mtibaa, Ahlem; Hallouma, Bilel; Mansour, Lamjed; Mellouli, Lotfi; Özdemir, Ismail; Yaşar, Sedat; Hamdi, Naceur

    2017-03-07

    New benzimidazolium salts 1a-c and their palladium bis-N-heterocyclic carbene complexes 2a-c and palladium PEPPSI-type complexes 3a-c were designed, synthesized and structurally characterized by NMR (1H and 13C), IR, DART-TOF mass spectrometry and elemental analysis. Then these complexes 2-3 were employed in the Suzuki-Miyaura cross-coupling reaction of substituted arenes with phenylboronic acid under mild conditions in toluene and DMF/H2O (1/1) to afford functionalized biaryl derivatives in good to excellent yields. The antibacterial activity of palladium bis-N-heterocyclic carbene complexes 2a-c and palladium PEPPSI-type complexes 3a-c was measured by disc diffusion method against Gram positive and Gram negative bacteria. Compounds 2a, 2c and 3a-c exhibited potential antibacterial activity against four bacterial species among the five used indicator cells. The product 2b inhibits the growth of the all five tested microorganisms. Moreover, the antioxidant activity determination of these complexes 2-3, using 2.2-diphenyl-1-picrylhydrazyl (DPPH) as a reagent, showed that compounds 2a-c and 3b possess DPPH antiradical activity. The higher antioxidant activity was obtained from the product 2b which has radical scavenging activity comparable to that of the two used positive controls (gallic acid "GA" and tutylatedhydroxytoluene "BHT"). Investigation of the anti-acetylcholinesterase activity of the studied complexes showed that compounds 2b, 3a, and 3b exhibited moderate activity at 100 μg/mL and product 2b is the most active.

  17. Hantzsch reaction and quinoxaline synthesis using 1-methyl-3-(2-(sulfooxyethyl-1H-imidazol-3-ium chloride as a new, efficient and BrØnsted acidic ionic liquid catalyst

    Directory of Open Access Journals (Sweden)

    Sami Sajjadifar

    2013-10-01

    Full Text Available In this work, the efficiency, generality and applicability of new BrØnsted acidic ionic liquid (BAIL 1-methyl-3-(2-(sulfooxyethyl-1H-imidazol-3-ium chloride {[Msei]Cl} as heterogeneous and green catalyst for organic transformations are studied. Herein, the following one-pot multi-component reactions in the presence of [Msei]Cl are investigated: (i the synthesis of quinoxaline derivatives from the reaction of phenylenediamines and 1,2-diketones in EtOH under mild conditions (room temperature, (ii the preparation of 1,4-dihydropyridines from one-pot multi component condensation of 1,3-dicarbonyl compounds, NH4OAcand aldehydes under solvent-free conditions at moderate temperature (90 °C. High yields, relatively short reaction times, efficiency, generality, clean process, simple methodology, low cost, easy work-up, ease of preparation and regeneration of the catalyst and green conditions (in the synthesis of the quinoxaline derivatives are advantages of the application of [Mesi]Cl as catalyst in the above organic reactions.

  18. Analytical correlation between varying corrosion parameters and corrosion rate of Al-4.5Cu/10%ZrSiO{sub 4} composite in hydrochloric acid by rare earth chloride

    Energy Technology Data Exchange (ETDEWEB)

    Oloche, O.B.; Yaro, S.A. [Department of Metallurgical Engineering Ahmadu Bello University, Zaria (Nigeria); Okafor, E.G. [Department of Metallurgical Engineering Ahmadu Bello University, Zaria (Nigeria)], E-mail: ekeneokafor@yahoo.com

    2009-03-20

    The effect of varying temperature, time and inhibitor concentration on the corrosion rate of Al-4.5Cu/ZrSiO{sub 4} composite in 0.5 M hydrochloric acid without and with lanthanide chloride salt have been investigated. 10%ZrSiO{sub 4} was used for the production of the Al-4.5Cu/zircon sand composite. The time, temperature and concentration of inhibitor were varied in the range of 6-10 h at 2 h interval, 30-75 deg. C at 15 deg. C interval and 250-1000 ppm at 250 ppm interval respectively. Factorial design, standard deviation, effect of variables at 95% confidence interval and Arrhenius kinetics approach were used to correlate the corrosion parameter and corrosion rate. Results show that increase in temperature, inhibitor concentration above 250 ppm and decrease in time enhance corrosion rate. Also, temperature and anti-corrosion agent concentration are the most important control parameters. The kinetic and statistical approaches were in good agreement.

  19. Asymmetric catalysis in aqueous media: use of metal-chiral crown ethers as efficient chiral Lewis acid catalysts in asymmetric aldol reactions

    Directory of Open Access Journals (Sweden)

    Shu Kobayashi

    2001-01-01

    Full Text Available Metal-chiral crown ether complexes have been developed as efficient chiral Lewis acid catalysts for asymmetric aldol reactions of silyl enol ethers with aldehydes in aqueous media. While many excellent catalytic asymmetric reactions have been developed recently, most of them have to be carried out under strictly anhydrous conditions in organic solvents. This is probably due to the instability of many catalysts and/or intermediates in the presence of even a small amount of water. To address this issue, we searched for metal-crown ether complexes on the basis of our "multi-coordination" hypothesis, and found that lead(II and lanthanide(III catalysts worked well as chiral Lewis acids in aqueous media. To the best of our knowledge, these are the first examples of chiral crown-based Lewis acids that can be successfully used in catalytic asymmetric reactions. The catalysts have been characterized by X-ray diffraction, and their unique structures as chiral catalysts have been revealed. Use of water as a solvent is essential in these asymmetric catalysis, and the role of water on these reactions to explain the high reactivity and selectivity has been suggested. Another important point is that kinetic studies have shown the possibility that these types of crown ether complexes would be suitable as chiral catalysts employed in aqueous media. In addition, although the catalytic asymmetric aldol reactions are one of the most powerful carbon-carbon bond-forming methodologies and several successful examples have been reported, the use of aprotic anhydrous solvents and low reaction temperatures (-78 °C has been needed in almost all successful cases. On the other hand, the present reactions proceeded smoothly at -10-0 °C in water-alcohol solutions while retaining high levels of diastereo- and enantioselectivities.

  20. Insights into the interplay of Lewis and Brønsted acid catalysts in glucose and fructose conversion to 5-(hydroxymethyl)furfural and levulinic acid in aqueous media.

    Science.gov (United States)

    Choudhary, Vinit; Mushrif, Samir H; Ho, Christopher; Anderko, Andrzej; Nikolakis, Vladimiros; Marinkovic, Nebojsa S; Frenkel, Anatoly I; Sandler, Stanley I; Vlachos, Dionisios G

    2013-03-13

    5-(Hydroxymethyl)furfural (HMF) and levulinic acid production from glucose in a cascade of reactions using a Lewis acid (CrCl3) catalyst together with a Brønsted acid (HCl) catalyst in aqueous media is investigated. It is shown that CrCl3 is an active Lewis acid catalyst in glucose isomerization to fructose, and the combined Lewis and Brønsted acid catalysts perform the isomerization and dehydration/rehydration reactions. A CrCl3 speciation model in conjunction with kinetics results indicates that the hydrolyzed Cr(III) complex [Cr(H2O)5OH](2+) is the most active Cr species in glucose isomerization and probably acts as a Lewis acid-Brønsted base bifunctional site. Extended X-ray absorption fine structure spectroscopy and Car-Parrinello molecular dynamics simulations indicate a strong interaction between the Cr cation and the glucose molecule whereby some water molecules are displaced from the first coordination sphere of Cr by the glucose to enable ring-opening and isomerization of glucose. Additionally, complex interactions between the two catalysts are revealed: Brønsted acidity retards aldose-to-ketose isomerization by decreasing the equilibrium concentration of [Cr(H2O)5OH](2+). In contrast, Lewis acidity increases the overall rate of consumption of fructose and HMF compared to Brønsted acid catalysis by promoting side reactions. Even in the absence of HCl, hydrolysis of Cr(III) decreases the solution pH, and this intrinsic Brønsted acidity drives the dehydration and rehydration reactions. Yields of 46% levulinic acid in a single phase and 59% HMF in a biphasic system have been achieved at moderate temperatures by combining CrCl3 and HCl.

  1. Capillary ion electrophoresis of inorganic anions and uric acid in human saliva using a polyvinyl alcohol coated capillary column and hexamethonium chloride as additive of background electrolyte.

    Science.gov (United States)

    Mori, Masanobu; Yamamoto, Tsukasa; Kaseda, Maki; Yamada, Sachiko; Itabashi, Hideyuki

    2012-03-01

    A combination of polyvinyl alcohol chemically coated capillary (PVA capillary) and background electrolyte (BGE) with ion-pair reagent (hexamethonium dichloride, HMC) was used on capillary ion electrophoresis-UV detection (CIE-UV) for analysis of Br⁻, I⁻, NO₂⁻, NO₃⁻, SCN⁻ and uric acid in human saliva. The PVA capillary prepared in our laboratory minimized electro-osmotic flow (EOF) at the BGE in pH 3-10, and did not affect the UV detection at 210 nm by the PVA-layer on capillary wall. Therefore, use of the PVA capillary was suitable for sensitive UV detection for analyte anions, as well as suppression of protein adsorption. In this study, we optimized the BGE of 10 mM phosphate plus 10 mM HMC with applying a voltage of -15 kV. HMC as an additive to BGE could manipulate the electrophoretic mobility of anions, without electrostatic adsorption to the PVA capillary. The CIE-UV could separate and determine analyte anions in human saliva containing proteins by the direct injection without pretreatments such as dilution or deproteinization within 13 min. The relative standard deviations (n=10) were ranged of 0.5-1.6% in migration times, 2.2-6.8% in peak heights and 2.8-8.4% in peak areas. The limits of detection (S/N=3) were ranged of 3.42-6.87 μM. The peak height of anions in this system was gradually decreased through the successive injections of saliva samples, but the problem was successfully solved by periodically conditioning the PVA capillary. The quantifiability of anions in human saliva samples by the CIE-UV was evaluated through the recoveries by standard addition methods and comparison of other representative analytical methods, as well as identification by ion chromatography (IC). From the anion analyses in 12 different saliva samples, the CIE-UV demonstrated that can obtain obvious differences in concentrations of SCN⁻ between of smoker and non-smoker and those of uric acid between male and female with satisfactory results.

  2. Benzalkonium Chloride and Glaucoma

    OpenAIRE

    Rasmussen, Carol A.; Kaufman, Paul L.; Kiland, Julie A.

    2014-01-01

    Glaucoma patients routinely take multiple medications, with multiple daily doses, for years or even decades. Benzalkonium chloride (BAK) is the most common preservative in glaucoma medications. BAK has been detected in the trabecular meshwork (TM), corneal endothelium, lens, and retina after topical drop installation and may accumulate in those tissues. There is evidence that BAK causes corneal and conjunctival toxicity, including cell loss, disruption of tight junctions, apoptosis and preapo...

  3. Molten Triazolium Chloride Systems as New Aluminum Battery Electrolytes

    DEFF Research Database (Denmark)

    Vestergaard, B.; Bjerrum, Niels; Petrushina, Irina

    1993-01-01

    The possibility of using molten mixtures of 1,4-dimethyl-1,2,4-triazolium chloride (DMTC) and aluminum chloride (AlCl3) as secondary battery electrolytes was studied, in some cases extended by the copresence of sodium chloride. DMTC-AlCl, mixtures demonstrated high specific conductivity in a wide...... of milliamperes per square centimeter) was observed at 0.344 V on the acidic sodium tetrachloroaluminate background, involving a free triazolium radical mechanism. Molten DMTC-AlCl3 electrolytes are acceptable for battery performance and both the aluminum anode and the triazolium electrolyte can be used as active...

  4. Correlation of biological value of feed phosphates with their solubility in water, dilute hydrogen chloride, dilute citric acid, and neutral ammonium citrate.

    Science.gov (United States)

    Sullivan, T W; Douglas, J H; Gonzalez, N J; Bond, P L

    1992-12-01

    Relative biological values (BV) of 36 feed phosphates were determined with female turkeys in bioassays of 21-day duration using three response criteria: weight gain, tibia ash percentage, and gain:feed ratio. Calcium phosphate, dibasic dihydrate (United States Pharmacopeia) was the reference standard. Nine mono-dicalcium phosphates (M-DCP, 21.0% phosphorus), 13 di-monocalcium phosphates (D-MCP, 18.5% phosphorus), and 14 defluorinated phosphates (DFP, 18.0% phosphorus) were evaluated. The average relative BV for M-DCP, D-MCP, and DFP samples were 97.6, 94.6, and 90.8%, respectively. Solubility of phosphates was determined by four recognized methods. The solvents were water, .4% HCl, 2.0% citric acid (CA), and neutral ammonium citrate (NAC). Water solubility of M-DCP samples was greater (67.5%) than that of D-MCP (38.8%) and DFP (8.9%) samples. Correlation of water solubility of phosphates to their relative BV was quite low, and water solubility was a poor indicator of BV. When .4% HCl was the solvent, correlation coefficients (r) were .55, .33, and .72 for M-DCP, D-MCP, and DFP, respectively. Based on these results and prediction equations, .4% HCl solubility would be inappropriate for estimating BV of M-DCP and D-MCP samples. Solubility of feed phosphates (mainly D-MCP and DFP) in 2.0% CA or NAC was positively correlated with BV; the r values were .87 to .95. Both of these solubility tests provided a good index of BV. However, it would seem inappropriate and risky to replace bioassays totally with these tests. Feed phosphate users could perform either the 2.0% CA or NAC solubility test easily as a screen for BV along with other quality control procedures (i.e., phosphorus, calcium, sodium, and fluoride determinations).

  5. Enrichment of sulfate-reducing bacteria and resulting mineral formation in media mimicking pore water metal ion concentrations and pH conditions of acidic pit lakes.

    Science.gov (United States)

    Meier, Jutta; Piva, Angela; Fortin, Danielle

    2012-01-01

    Acid mine drainage sites are extreme environments with high acidity and metal ion concentrations. Under anoxic conditions, microbial sulfate reduction may trigger the formation of secondary minerals as a result of H2S production and pH increase. This process was studied in batch experiments with enrichment cultures from acidic sediments of a pit lake using growth media set at different pH values and containing elevated concentrations of Fe²⁺ and Al³⁺. At initial pH values of 5 and 6, sulfate reduction occurred shortly after inoculation. Sulfate- reducing bacteria affiliated to the genus Desulfosporosinus predominated the microbial communities as shown by 16S rRNA gene analysis performed at the end of the incubation. At initial pH values of 3 and 4, sulfate reduction and cell growth occurred only after an extended lag phase, however, at a higher rate than in the less acidic assays. At the end of the growth phase, enrichments were dominated by Thermodesulfobium spp. suggesting that these sulfate reducers were better adapted to acidic conditions. Iron sulfides in the bulk phase were common in all assays, but specific aluminum precipitates formed in close association with cell surfaces and may function as a detoxification mechanism of dissolved Al species at low pH.

  6. Recovering germanium from coal ash by chlorination with ammonium chloride

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    A new process of enriching germanium from coal ash was developed. The process involves in mixing the coal ash and ammonium chloride and then roasting the mixture to produce germanium chloride that is then absorbed by dilute hydrochloric acid and hydrolyzed to germanium oxide. The germanium recovery reached to 80.2% at the optimum condition: mass ratio of NH4Cl/coal ash is 0.15, roasting temperature 400℃ and roasting time 90 min.

  7. Use of ferric sulfate: acid media for the desulfurization of model compounds of coal. [Dibenzothiophene, diphenyl sulfide, di-n-butyl sulfide

    Energy Technology Data Exchange (ETDEWEB)

    Clary, L.R.; Vermeulen, T.; Lynn, S.

    1980-12-01

    The objective of this work has been to investigate the ability of ferric sulfate-acid leach systems to oxidize the sulfur in model compounds of coal. Ferric iron-acid leach systems have been shown to be quite effective at removal of inorganic sulfur in coal. In this study, the oxidative effect of ferric iron in acid-leach systems was studied using dibenzothiophene, diphenyl sulfide, and di-n-butyl sulfide as models of organic sulfur groups in coal. Nitrogen and oxygen, as well as various transition metal catalysts and oxidants, were utilized in this investigation. Dibenzothiophene was found to be quite refractory to oxidation, except in the case where metavanadate was added, where it appears that 40% oxidation to sulfone could have occurred per hour at 150/sup 0/C and mild oxygen pressure. Diphenyl sulfide was selectively oxidized to sulfoxide and sulfone in an iron and oxygen system. Approximately 15% conversion to sulfone occurred per hour under these conditions. Some of the di-n-butyl sulfide was cracked to 1-butene and 1-butanethiol under similar conditions. Zinc chloride and ferric iron were used at 200/sup 0/C in an attempt to desulfonate dibenzothiophene sulfone, diphenyl sulfone, and di-n-butyl sulfone. Di-n-butyl sulfone was completely desulfurized on one hour and fragmented to oxidized parafins, while dibenzothiophene sulfone and diphenyl sulfone were unaffected. These results suggest that an iron-acid leach process could only selectively oxidize aryl sulfides under mild conditions, representing only 20% of the organic sulfur in coal (8% of the total sulfur). Removal through desulfonation once selective sulfur oxidation had occurred was only demonstrated for alkyl sulfones, with severe oxidation of the fragmented paraffins also occurring in one hour.

  8. Mechanism of block of single protopores of the Torpedo chloride channel ClC-0 by 2-(p-chlorophenoxy)butyric acid (CPB).

    Science.gov (United States)

    Pusch, M; Accardi, A; Liantonio, A; Ferrera, L; De Luca, A; Camerino, D C; Conti, F

    2001-07-01

    We investigated in detail the mechanism of inhibition by the S(-) enantiomer of 2-(p-chlorophenoxy)butyric acid (CPB) of the Torpedo Cl(-)channel, ClC-0. The substance has been previously shown to inhibit the homologous skeletal muscle channel, CLC-1. ClC-0 is a homodimer with probably two independently gated protopores that are conductive only if an additional common gate is open. As a simplification, we used a mutant of ClC-0 (C212S) that has the common gate "locked open" (Lin, Y.W., C.W. Lin, and T.Y. Chen. 1999. J. Gen. Physiol. 114:1-12). CPB inhibits C212S currents only when applied to the cytoplasmic side, and single-channel recordings at voltages (V) between -120 and -80 mV demonstrate that it acts independently on individual protopores by introducing a long-lived nonconductive state with no effect on the conductance and little effect on the lifetime of the open state. Steady-state macroscopic currents at -140 mV are half-inhibited by approximately 0.5 mM CPB, but the inhibition decreases with V and vanishes for V > or = 40 mV. Relaxations of CPB inhibition after voltage steps are seen in the current responses as an additional exponential component that is much slower than the gating of drug-free protopores. For V = 60 mV) with an IC50 of approximately 30-40 mM. Altogether, these findings support a model for the mechanism of CPB inhibition in which the drug competes with Cl(-) for binding to a site of the pore where it blocks permeation. CPB binds preferentially to closed channels, and thereby also strongly alters the gating of the single protopore. Since the affinity of CPB for open WT pores is extremely low, we cannot decide in this case if it acts also as an open pore blocker. However, the experiments with the mutant K519E strongly support this interpretation. CPB block may become a useful tool to study the pore of ClC channels. As a first application, our results provide additional evidence for a double-barreled structure of ClC-0 and ClC-1.

  9. Growth and development of moringa (Moringa oleifera L. stem cuttings as affected by diameter magnitude, growth media, and indole-3-butyric acid

    Directory of Open Access Journals (Sweden)

    Shamsuddeen Rufai

    2016-12-01

    Full Text Available The acknowledged status of Moringa oleifera L. in sub-Saharan Africa, especially western Africa, has of recent accorded it the significance of being a good source of income to a large segment of many of its populace. Intensification of research into the realization of its full economic potential will be of utmost value to impoverished societies globally. One way to achieve this is the full exploration of all possible means that will facilitate its successful growth, propagation, and domestication. Even though it can be successfully raised through seeds, the high level outcrossing (64.3% observed is a hindrance to realization of true to type trees. Vegetative propagation can be employed as an option to tackle the noted limitation, ease the cultivation process, and achieve the required realization of its economic potential. Our trial was carried out to study the influence of two growth media and three levels of indole 3-butyric acid (IBA on root and shoot development in cuttings taken from a coppiced moringa tree existent in Universiti Putra Malaysia. Semi-hardwood cuttings of moringa, of between 20 and 30 mm diameter, cut into 25 cm length, were obtained, rinsed with a fungicide, then dipped, through their basal portion, inside varying levels (0, 1000, 2000, and 3000 ppm of indole-3-butyric acid (IBA for between 7 and 10 seconds. The treated cuttings were then transplanted into a polyethylene bags (23 cm × 36 cm, containing two growth media - a munchong series soil (M and a combination of a munchong series soil thoroughly mixed with biochar (MB in a 3:1 ratio sequence. The trial was conducted inside a shade house where the humidity of the experimental area was manipulated through a regular daily manual hand sprinkling. Plant height, percentage of primary branch produced, leaf area, and dry matter (DM were found to be significantly (P<0.05 influenced by variation in stem diameter magnitude, while the diameter of the primary branch and spad

  10. Growth and development of moringa (Moringa oleifera L. stem cuttings as affected by diameter magnitude, growth media, and indole-3-butyric acid

    Directory of Open Access Journals (Sweden)

    Shamsuddeen Rufai

    2016-12-01

    Full Text Available The acknowledged status of Moringa oleifera L. in sub-Saharan Africa, especially western Africa, has of recent accorded it the significance of being a good source of income to a large segment of many of its populace. Intensification of research into the realization of its full economic potential will be of utmost value to impoverished societies globally. One way to achieve this is the full exploration of all possible means that will facilitate its successful growth, propagation, and domestication. Even though it can be successfully raised through seeds, the high level outcrossing (64.3% observed is a hindrance to realization of true to type trees. Vegetative propagation can be employed as an option to tackle the noted limitation, ease the cultivation process, and achieve the required realization of its economic potential. Our trial was carried out to study the influence of two growth media and three levels of indole 3-butyric acid (IBA on root and shoot development in cuttings taken from a coppiced moringa tree existent in Universiti Putra Malaysia. Semi-hardwood cuttings of moringa, of between 20 and 30 mm diameter, cut into 25 cm length, were obtained, rinsed with a fungicide, then dipped, through their basal portion, inside varying levels (0, 1000, 2000, and 3000 ppm of indole-3-butyric acid (IBA for between 7 and 10 seconds. The treated cuttings were then transplanted into a polyethylene bags (23 cm × 36 cm, containing two growth media - a munchong series soil (M and a combination of a munchong series soil thoroughly mixed with biochar (MB in a 3:1 ratio sequence. The trial was conducted inside a shade house where the humidity of the experimental area was manipulated through a regular daily manual hand sprinkling. Plant height, percentage of primary branch produced, leaf area, and dry matter (DM were found to be significantly (P<0.05 influenced by variation in stem diameter magnitude, while the diameter of the primary branch and spad

  11. Copper electrodeposition from an acidic plating bath containing accelerating and inhibiting organic additives

    Energy Technology Data Exchange (ETDEWEB)

    Pasquale, M.A. [Instituto de Investigaciones Fisicoquimicas Teoricas y Aplicadas (INIFTA), Universidad Nacional de La Plata-Consejo Nacional de Investigaciones Cientificas y Tecnicas, Sucursal 4, Casilla de Correo 16, (1900), La Plata (Argentina)], E-mail: miguelp@inifta.unlp.edu.ar; Gassa, L.M.; Arvia, A.J. [Instituto de Investigaciones Fisicoquimicas Teoricas y Aplicadas (INIFTA), Universidad Nacional de La Plata-Consejo Nacional de Investigaciones Cientificas y Tecnicas, Sucursal 4, Casilla de Correo 16, (1900), La Plata (Argentina)

    2008-08-20

    Copper electrodeposition on copper from still plating solutions of different compositions was investigated utilising electrochemical impedance spectroscopy (EIS), cyclic voltammetry, and scanning electron microscopy (SEM). An acid copper sulphate plating base solution was employed either with or without sodium chloride in the presence of a single additive, either polyethylene glycol (PEG) or 3-mercapto-2-propanesulphonic acid (MPSA), and their mixture. Thallium underpotential deposition/anodic stripping was employed to determine the adsorption capability of additives on copper. In the absence of chloride ions, MPSA shows a moderate adsorption on copper, whereas PEG is slightly adsorbed. At low cathodic overpotentials, the simultaneous presence of MPSA and chloride ions accelerates copper electrodeposition through the formation of an MPSA-chloride ion complex in the solution, particularly for about 220 {mu}M sodium chloride. The reverse effect occurs in PEG-sodium chloride plating solutions. In this case, from EIS data the formation of a film that interferes with copper electrodeposition can be inferred. At higher cathodic overpotentials, when copper electrodeposition is under mass transport control, the cathode coverage by a PEG-copper chloride-mediated film becomes either partially or completely detached as the concentration of chloride ions at the negatively charged copper surface diminishes. The copper cathode grain topography at the {mu}m scale depends on the cathodic overpotential, plating solution composition and average current density. Available data about the solution constituents and their adsorption on copper make it possible to propose a likely complex mechanism to understand copper electrodeposition from these media, including the accelerating effect of MPSA and the dynamics of PEG-copper chloride complex adsorbate interfering with the surface mobility of depositing copper ad-ions/ad-atoms.

  12. Monitoring utilizations of amino acids and vitamins in culture media and Chinese hamster ovary cells by liquid chromatography tandem mass spectrometry.

    Science.gov (United States)

    Qiu, Jinshu; Chan, Pik Kay; Bondarenko, Pavel V

    2016-01-01

    Monitoring amino acids and vitamins is important for understanding human health, food nutrition and the culture of mammalian cells used to produce therapeutic proteins in biotechnology. A method including ion pairing reversed-phase liquid chromatography with tandem mass spectrometry was developed and optimized to quantify 21 amino acids and 9 water-soluble vitamins in Chinese hamster ovary (CHO) cells and culture media. By optimizing the chromatographic separation, scan time, monitoring time window, and sample preparation procedure, and using isotopically labeled (13)C, (15)N and (2)H internal standards, low limits of quantitation (≤0.054 mg/L), good precision (amino acids showed a zigzag pattern with maxima at the feeding days, and 9 non-essential amino acids displayed a smoothly changing profile as they were mainly products of cellular metabolism. Five of 9 vitamins accumulated continuously during the culture period, suggesting that they were fed in access. The method serves as an effective tool for the development and optimization of mammalian cell cultures.

  13. Separation Studies of Pd(II from Acidic Chloride Solutions of Pt(IV, Ni(II and Rh(III by Using 4-Aroyl-3-Phenyl-5-Isoxazolones

    Directory of Open Access Journals (Sweden)

    Koduru Janardhan Reddy

    2012-01-01

    Full Text Available This study examined the effect influence of various factors on the extraction of Pd(II to develop a new liquid-liquid extraction mechanism for the selective separation of palladium(II from its acidic chloride solutions using 4-aroyl-3-phenyl-5-isoxazolones (HA, such as 3-phenyl-4-(4-fluorobenzoyl-5- isoxazolone (HFBPI, 3-phenyl-4-benzoyl-5-isoxazolone (HPBI and 3-phenyl-4- (4-toluoyl-5-isoxazolone (HTPI. The extraction strength of Pd(II with HA were in the following order: HFBPI > HPBI > HTPI, which is opposite to that observed with their pKa values. HPBI was used to separate Pd(II from Pt(IV, Ni(II and Rh(III metal ions and calculated their separation factors (S.F. were followed in the order: Pd/Ni (40±0.4 > Pd/Pt (25±0.2 > Pd/Rh (15±0.3 > Rh/Ni (2.7±0.3 > Pt/Ni ≈ Rh/Pt (1.7±0.2. The loading and striping of Pd(II (1.12×10-4 mol L-1 were also examined using 1.0×10-3 mol L-1 HPBI in CHCl3 and 1.0 mol L-1 HCl, respectively. The results demonstrated that the maximum (97.5% extraction and desorption (89% of metal required at least 3.0 cycles. The developed method was applied successfully to the separation of palladium from synthetic water samples.

  14. Experimental research on the preparation of polyferric aluminum chloride by acid pickle and spent lye%以废酸、废碱液制备聚合氯化铁铝的实验研究

    Institute of Scientific and Technical Information of China (English)

    邵青; 霍文敏; 苑运丽; 王震

    2012-01-01

    以钢厂含铁废酸和铝加工业含铝废碱及废铁屑为原料制备聚合氯化铁铝(PFAC).实验研究了废铁屑加入量等因素对Fe2+溶出率的影响,同时研究了Fe2+的氧化条件.结果表明,在25℃、反应时间为15~20 min、氧化剂氯酸钠加入量等于化学计量值时,Fe2+氧化率可达98.7%以上.用废碱液调整盐基度,PFAC盐基度为20%时,对活性蓝P-3R水溶液的A590去除率可达99.8%;并对PFAC样品进行了红外光谱表征.%Iron-containing acid pickle in steel works,aluminum-containing spent lye in aluminum processing industry and waste iron scraps have been used as raw materials for preparing polyferric aluminum chloride (PFAC). The influence of waste iron scraps dosage and other factors on Fe2+ dissolution rate is studies. The oxidation rate of Fe2+ is 98.7%,when the oxidation conditions are as follows: its temperature is 25 ℃, reaction time 15-20 min,and the dosage of sodium chlorate equals to stoichiometric value. Spent lye is used for adjusting the PFAC basicity to 20%. The As90 removing rate of the activated Blue P-3R aqueous solution can reach 99.8%; and the PFAC samples are characterized by infrared spectroscopy.

  15. Oxomemazine hydro-chloride.

    Science.gov (United States)

    Siddegowda, M S; Butcher, Ray J; Akkurt, Mehmet; Yathirajan, H S; Ramesh, A R

    2011-08-01

    IN THE TITLE COMPOUND [SYSTEMATIC NAME: 3-(5,5-dioxo-phen-othia-zin-10-yl)-N,N,2-trimethyl-propanaminium chloride], C(18)H(23)N(2)O(2)S(+)·Cl(-), the dihedral angle between the two outer aromatic rings of the phenothia-zine unit is 30.5 (2)°. In the crystal, the components are linked by N-H⋯Cl and C-H⋯Cl hydrogen bonds and C-H⋯π inter-actions.

  16. Understanding microwave vessel contamination by chloride species.

    Science.gov (United States)

    Recchia, Sandro; Spanu, Davide; Bianchi, Davide; Dossi, Carlo; Pozzi, Andrea; Monticelli, Damiano

    2016-10-01

    Microwaves are widely used to assist digestion, general sample treatment and synthesis. The use of aqua regia is extensively adopted for the closed vessel mineralization of samples prior to trace element detection, leading to the contamination of microwave vessels by chlorine containing species. The latter are entrapped in the polymeric matrix of the vessels, leading to memory effects that are difficult to remove, among which the risk of silver incomplete recoveries by removal of the sparingly soluble chloride is the predominant one. In the present paper, we determined by mass spectrometry that hydrogen chloride is the species entrapped in the polymeric matrix and responsible for vessel contamination. Moreover, several decontamination treatments were considered to assess their efficiency, demonstrating that several cleaning cycles with water, nitric acid or silver nitrate in nitric acid were inefficient in removing chloride contamination (contamination reduction around 90%). Better results (≈95% decrease) were achieved by a single decontamination step in alkaline environment (sodium hydroxide or ammonia). Finally, a thermal treatment in a common laboratory oven (i.e. without vacuum and ventilation) was tested: a one hour heating at 150°C leads to a 98.5% decontamination, a figure higher than the ones obtained by wet treatments which requires comparable time. The latter treatment is a major advancement with respect to existing treatments as it avoids the need of a vacuum oven for at least 17h as presently proposed in the literature.

  17. Copper- or manganese-doped ZnS quantum dots as fluorescent probes for detecting folic acid in aqueous media

    Energy Technology Data Exchange (ETDEWEB)

    Geszke-Moritz, Malgorzata [Laboratoire Reactions et Genie des Procedes (LRGP), Nancy-University, CNRS, 1 rue Grandville, 54001 Nancy Cedex (France); Department of Pharmaceutical Technology, Poznan University of Medical Sciences, Grunwaldzka 6, 60-780 Poznan (Poland); Clavier, Gilles [PPSM, ENS Cachan, CNRS, UniverSud, 61 avenue President Wilson, 94230 Cachan (France); Lulek, Janina [Department of Pharmaceutical Technology, Poznan University of Medical Sciences, Grunwaldzka 6, 60-780 Poznan (Poland); Schneider, Raphaeel, E-mail: raphael.schneider@ensic.inpl-nancy.fr [Laboratoire Reactions et Genie des Procedes (LRGP), Nancy-University, CNRS, 1 rue Grandville, 54001 Nancy Cedex (France)

    2012-04-15

    3-Mercaptopropionic acid-capped core/shell ZnS:Cu/ZnS and ZnS:Mn/ZnS doped quantum dots (QDs) prepared through hydrothermal methods exhibit high photoluminescence intensity as well as good photostability. These water-dispersible nanoparticles exhibit high fluorescence sensitivity to folic acid due to the high affinity of the carboxylate groups and nitrogen atoms of folic acid towards the Zn surface atoms of the doped dots. Quenching of the fluorescence intensity of the QDs allows the detection of folic acid concentrations as low as 11 {mu}M, thus affording a very sensitive system for the sensing of this biologically active molecule in aqueous solution. The possible quenching mechanism is discussed. - Graphical abstract: A sensitive method for the detection of folic acid based on the fluorescence quenching of Mn- or Cu-doped ZnS quantum dots was developed. Highlights: Black-Right-Pointing-Pointer Quenching of the fluorescence intensity of doped ZnS QDs in the presence of folic acid. Black-Right-Pointing-Pointer New fluorescent sensors for folic acid. Black-Right-Pointing-Pointer Detection of folic acid concentrations as low as 11 {mu}M in aqueous solution. Black-Right-Pointing-Pointer The Perrin model and fluorescence lifetimes of ZnS:Mn QDs demonstrate a static quenching mechanism. Black-Right-Pointing-Pointer Quenching efficiency of ZnS:Cu QDs correlates with the Stern-Volmer model.

  18. Inhibitory Kinetic Spectrophotometric Determination of Citric Acid with Benzyltriethylammonium Chloride as Sensitizer%苄基三乙基氯化铵增敏阻抑动力学光度法测定食品中的柠檬酸

    Institute of Scientific and Technical Information of China (English)

    倪秀珍; 王晓菊

    2012-01-01

    A new inhibitory catalytic kinetic spectrophotometric method for die determination of trace amount of citric acid was developed based on that citric acid can inhibit the discoloration of the catalytic oxidation reaction of Spirit Blue with KBRO3 by NO2"in the presence of HAc solution using cationic surfactant of Benzyltriethylammonium chloride as an sensitizer. The effects of the factors such as absorption spectra, acidity, concentrations of reagent and coexisting ions, on the reaction are discussed and the kinetic conditions were studied. Under the optimum conditions, good linear relationship was obtained between absorbance difference (AA) of the inhibited system and non-inhibited system at S20 nm and the concentration of citric acid in the range of 4-128 ug/L with the detection limit of 3.09×10-6 g/L. The catalytic reaction was the zero-order reaction and apparent activation energy of the catalytic reaction 138.2 kJ/mol, and the reaction rate constant was corresponding to 2.16x10-3 mol/Lmin. The sensitivity was increased by 2.6 times than in the absence of the surfactant. The method can be used for the determination of citric acid in water with satisfactory result.%在HAc溶液中,柠檬酸对NO2-催化KBrO3氧化苯胺蓝的褪色反应具有抑制作用,阳离子表面活性剂苄基三乙基氯化铵对此体系有强烈增敏作用,据此建立了阻抑动力学光度法测定痕量柠檬酸的新方法.研究了吸收光谱、试剂用量、干扰离子等因素的影响,测定了动力学参数.在最佳实验条件下,阻抑反应与非阻抑反应体系在600nm处的吸光度差值与柠檬酸的质量浓度在4~128μg/L范围内呈良好线性关系,检测限为3.09× 10-6 g/L.催化反应为动力学零级反应,表现活化能为138.2 kJ/mol,反应速率常数为2.16×10-3 mol/Lmin.在表面活性剂存在下,灵敏度提高2.6倍.此法用于汽水中柠檬酸的测定,结果满意.

  19. Determination of aluminum in aluminum electrolyte by EDTA back titration with ethanol-cuprous chloride-ammonium chloride-hydrochloric acid complex solvent separation%乙醇-氯化亚铜-氯化铵-盐酸复合溶剂分离-EDTA返滴定法测定铝电解质中单质铝

    Institute of Scientific and Technical Information of China (English)

    蒲秋梅; 任凤莲; 曹福悦

    2011-01-01

    新型低温铝电解质体系物相组成复杂,单质铝的分离测定尤为困难.本文采用高选择性复合溶剂乙醇-氯化亚铜-氯化铵-盐酸(ECAH)直接分离后测定铝电解质中单质铝,成功解决了单质铝与其它铝的化合物分离困难的问题,有效降低了铝电解质溶样时铝的氟化物的微溶效应带来的误差,为铝电解质中单质铝的物相分析提供了可靠的研究方案.采用经典ED-TA络合返滴定法测得铝电解质样品中单质铝含量,加标回收率在97%~103%之间,RSD(n=6)为1.1%和1.5%.测定结果和Al-CAS-OP-CPC四元络合光度法测定结果进行比对,结果一致.%It was particularly difficult to separate and determine aluminum in new low-temperature aluminum electrolyte system because of its complicated components. In this paper, aluminum in aluminum electrolyte was directly separated and determined using high-selectivity ethanol -cuprous chlorideammomum chloride-hydrochloric acid (ECAH) as complex solvent. This method successfully settled the problem of difficult separation of aluminum from aluminum compounds, effectively reduced the determination error introduced by slight soluble effect of fluoride of aluminum during the dissolution of aluminum electrolyte, and provided a reliable research method for the phase analysis of aluminum in aluminum electrolyte. Aluminum in aluminum electrolyte samples was determined by classic EDTA complexing back titration method. The standard addition recoveries were 97%-103 %, and the relative standard deviations (RSD, n=6) were 1. 1 % and 1. 5 %, respectively. The determination results were in good agreement with those obtained by Al-CAS-OP-CPC quaternary complex photometry.

  20. Carbonisation of coal with chlorides content

    Energy Technology Data Exchange (ETDEWEB)

    E. Plevova

    2002-07-01

    From accessible literature it is evident that the addition of Lewis acids to coal before carbonisation can effect the course of reactions in the way of getting required products. An investigation was carried out into the effects of addition of chloride solutions. For experiments low concentration of solutions of three chlorides (PbCl{sub 2}, ZnCl{sub 2}, AlC{sub 3}) were used. Then samples were carbonised in a special coking retort. Volatile products were collected to establish the mass balance of this process. The resultant properties of obtained char and coal tar were estimated. Evaluation of the solid phase showed the increasing of specific surface although the used solution concentration was quite low. Estimation of obtained tar indicated mainly increasing of aromatic hydrocarbons in consequence of charring and aromatisation of carbon skeleton. 3 refs., 1 fig., 3 tabs.

  1. Iron (III) chloride doping of CVD graphene.

    Science.gov (United States)

    Song, Yi; Fang, Wenjing; Hsu, Allen L; Kong, Jing

    2014-10-03

    Chemical doping has been shown as an effective method of reducing the sheet resistance of graphene. We present the results of our investigations into doping large area chemical vapor deposition graphene using Iron (III) Chloride (FeCl(3)). It is shown that evaporating FeCl(3) can increase the carrier concentration of monolayer graphene to greater than 10(14) cm(-2) and achieve resistances as low as 72 Ω sq(-1). We also evaluate other important properties of the doped graphene such as surface cleanliness, air stability, and solvent stability. Furthermore, we compare FeCl(3) to three other common dopants: Gold (III) Chloride (AuCl(3)), Nitric Acid (HNO(3)), and TFSA ((CF(3)SO(2))(2)NH). We show that compared to these dopants, FeCl(3) can not only achieve better sheet resistance but also has other key advantages including better solvent stability.

  2. 一种新型可光降解的PVC-OA-TiO_2纳米复合膜%A Novel Photodegradable Polyvinyl Chloride-Oxalic Acid-TiO_2 Nanocomposite Film

    Institute of Scientific and Technical Information of China (English)

    法文君; 龚楚清; 杨昌军; 彭天右; 昝菱

    2009-01-01

    A novel kind of photodegradable polyvinyl chloride-oxalic acid-TiO_2(PVC-OA-TiO_2) nano-composite film was prepared by blending the nano-TiO_2 particles into the commercial PVC.Oxalic acid,as a good election donor,can suppress the recombination of electrons and holes on the TiO_2 surface,so it enhances the photocatalytic efficiency of nano-TiO_2.The weight loss of PVC-OA-TiO_2 composite film reached 55% after 310 h UV-light irradiation,which was twice of PVC-TiO_2 film or 3.5 times of pure PVC film.The results indicate that PVC-OA-TiO_2 composite film has better photocatalytic degradation efficiency than PVC-TiO_2 composite film and pure PVC film.%采用包埋技术制备了一种新型可光降解的聚氯乙烯-草酸-TiO_2(PVC-OA-TiO_2)纳米复合膜,并研究了紫外光照射条件下该复合膜的光催化降解情况.结果表明,该纳米复合膜的光催化降解是一个氧化断链过程,经紫外光照射310 h后失重率达到55%,是PVC-TiO_2复合膜的2倍,是纯PVC膜的3.5倍,说明草酸的掺杂可以促进PVC-OA-TiO_2复合膜更快地被光降解.草酸作为一个良好的电子给体,能不可逆地与TiO_2表面产生的空穴或表面羟基反应,抑制电子和空穴的复合,从而显著提高PVC-OA-TiO_2的光催化降解速率.

  3. Spectrophotometric determination of acidity constant of some indicators in various micellar media solutions by rank annihilation factor analysis.

    Science.gov (United States)

    Niazi, Ali; Zolgharnein, Javad; Davoodabadi, Mohammad Reza

    2008-07-01

    Rank annihilation factor analysis (RAFA) was used to the spectrophotometric studies of the acidity constant of methyl orange, methyl red and methyl violet in water and different micellar solutions at 25 degrees C and an ionic strength of 0.1M. When the acidity constants (surfactant concentration dependent acidity constant) acts as an optimizing object, and simply combined with the pure spectrum of acidic and basic forms, the rank of original data matrix can be reduced. The residual standard deviation (R.S.D.) of the residual matrix after bi-linearization of the background matrix is regarded as the evaluation function. Results show that the acidity constant of these indicators are influenced as the percentages of neutral, cationic and anionic surfactant such as Triton X-100 (poly(oxyethylene)(9.5)p-(1,1,3,3-tetramethyl), sodiumdodecylsulfate (SDS) and cethyltrimethylammonium (CTAB), respectively, added to the solution of these reagents. Also, RAFA is an efficient chemometrics algorithm for completely analysis of acid-base equilibrium systems by spectrophotometric method. Effects of surfactant on acidity constant and absorption spectra are also discussed.

  4. An Apical-Membrane Chloride Channel in Human Tracheal Epithelium

    Science.gov (United States)

    Welsh, Michael J.

    1986-06-01

    The mechanism of chloride transport by airway epithelia has been of substantial interest because airway and sweat gland-duct epithelia are chloride-impermeable in cystic fibrosis. The decreased chloride permeability prevents normal secretion by the airway epithelium, thereby interfering with mucociliary clearance and contributing to the morbidity and mortality of the disease. Because chloride secretion depends on and is regulated by chloride conductance in the apical cell membrane, the patch-clamp technique was used to directly examine single-channel currents in primary cultures of human tracheal epithelium. The cells contained an anion-selective channel that was not strongly voltage-gated or regulated by calcium in cell-free patches. The channel was also blocked by analogs of carboxylic acid that decrease apical chloride conductance in intact epithelia. When attached to the cell, the channel was activated by isoproterenol, although the channel was also observed to open spontaneously. However, in some cases, the channel was only observed after the patch was excised from the cell. These results suggest that this channel is responsible for the apical chloride conductance in airway epithelia.

  5. Adsorption of 2-X-benzoic acids (X = fluoro, chloro, and bromo) on Au(1 0 0) electrode in acidic media studied by IRAS

    Energy Technology Data Exchange (ETDEWEB)

    Ikezawa, Yasunari [Department of Chemistry, Faculty of Science, Rikkyo University, Nishi-Ikebukuro, Toshima-Ku, Tokyo 171 (Japan)]. E-mail: ikezawa@rikkyo.ac.jp; Yoshida, Atsushi [Department of Chemistry, Faculty of Science, Rikkyo University, Nishi-Ikebukuro, Toshima-Ku, Tokyo 171 (Japan); Ariga, Toshiyuki [Department of Chemistry, Faculty of Science, Rikkyo University, Nishi-Ikebukuro, Toshima-Ku, Tokyo 171 (Japan)

    2006-05-05

    Adsorption behaviors of 2-fluoro-, 2-chloro-, and 2-bromobenzoic acids on Au(1 0 0) electrode in 0.1 M HClO{sub 4} have been investigated by using in situ reflection adsorption IR spectroscopy and differential capacity measurements. It is found for the 2-substitued benzoic acids that the flat lying adsorbed species is present at negative potentials, and the vertically adsorbed benzoate with both oxygen atoms oriented toward the metal surface is present at positive potentials. A new adsorbed state due to the vertical orientation was observed around 0.75 V only in 2-fluorobenzoic acid solution, as well as the case of benzoic acid. This indicates that the new band is due to the formation of an ordered adsorption layer of the vertical 2-fluorobenzoate, and the formation of the arrangement adsorption is dependent on the size of the adsorbed molecule.

  6. Investigation of adsorption and inhibitive effect of acid red GRE (183 dye on the corrosion of carbon steel in hydrochloric acid media

    Directory of Open Access Journals (Sweden)

    M. Abd El-raouf

    2015-09-01

    Full Text Available The adsorption and corrosion inhibitive effect of acid red GRE (183 dye on carbon steel alloy in 1 M HCl solutions was studied using various techniques. Results of weight loss, Tafel polarization measurements and electrochemical impedance spectroscopy (EIS techniques show that this compound has fairly good inhibiting properties for steel corrosion in acidic bath; with efficiency around 96% at a concentration of 50 ppm. The inhibition is of a mixed anodic–cathodic nature. Factors affecting the corrosion process have been calculated and discussed. Acid red GRE (183 dye was shown to be an inhibitor in the acidic corrosion. Inhibition efficiency increased with acid red GRE (183 dye concentration but decreased with rise in temperature, corrosion inhibition is attributed to the adsorption of acid red GRE (183 dye on the carbon steel surface via a physical adsorption mechanism. Langmuir isotherm is found to provide an accurate description of the adsorption behavior of the investigated azo compound. The nature of the protective film was investigated using SEM and EDX techniques.

  7. 色媒体改性棉织物酸性染料浸染染色%Acid Dyes Dip Dyeing on Cotton Fabric Modified by Color Media

    Institute of Scientific and Technical Information of China (English)

    王洪海

    2015-01-01

    采用阳离子改性剂色媒体对棉织物进行改性处理,之后用酸性染料染色。探讨并分析了改性剂色媒体用量、染色温度、染色时间、染色浴比等工艺参数对染色效果的影响,优化改性棉织物酸性染料浸染染色工艺,并介绍了改性棉织物染色后的固色处理工艺。结果表明,当染料用量为1.0%时,优化的工艺条件为:改性剂色媒体用量为3.0%,染色温度70℃,染色时间40 min,浴比1∶30;改性棉织物染色后具有较好的耐摩擦色牢度和沾色牢度,但耐皂洗褪色牢度较差,应加以进一步的固色处理,高分子固色剂DM的最佳用量为2.0%。%Cotton fabric was modified by cationic modifier color media and dyed by acid dyes. The effects of the dosage of modifier color media, dyeing temperature, dyeing time and bath ratio on dyeing effect were discussed and analyzed, dip dyeing process of modified cotton fabric with acid dyes was optimized, and the fixation process of modified cotton fabric was introduced. The results show that when the dosage of acid dyes is 1.0%, the optimal process conditions are that the dosage of color media is 3.0%, dyeing temperature is 70 ℃, dyeing time is 40 minutes, bath ratio is 1∶30; modified cotton fabric has good fastness to rubbing and staining, but the fastness to soaping is poor; it should be treated by further fixation, and the suitable dosage of macromolecule fixing agent DM is 2.0%.

  8. Corrosion Inhibition and Adsorption Properties of Ethanolic Extract of Calotropis for Corrosion of Aluminium in Acidic Media

    OpenAIRE

    Sudesh Kumar; Suraj Prakash Mathur

    2013-01-01

    The corrosion inhibition of aluminium in sulfuric acid solution in the presence of different plant parts, namely, leaves, latex, and fruit was studied using weight loss method and thermometric method. The ethanolic extracts of Calotropis procera and Calotropis gigantea act as an inhibitor in the acid environment. The inhibition efficiency increases with increase in inhibitor concentration. The plant parts inhibit aluminium, and inhibition is attributed, due to the adsorption of the plant part...

  9. Qualidade de kiwis minimamente processados e submetidos a tratamento com ácido ascórbico, ácido cítrico e cloreto de cálcio Quality of kiwis minimally processed and treated with ascorbic acid, citric acid and calcium chloride

    Directory of Open Access Journals (Sweden)

    Ana Vânia Carvalho

    2002-05-01

    Full Text Available Frutos e hortaliças minimamente processados devem apresentar atributos de conveniência e qualidade do produto fresco. O objetivo deste trabalho foi estudar o efeito do processamento mínimo de frutos tratados com soluções a 1% de ácido ascórbico, ácido cítrico e cloreto de cálcio, durante armazenamento refrigerado, na qualidade do kiwi (Actinidia deliciosa cv. Hayward. A perda de massa foi mínima durante o período de armazenamento. O ácido ascórbico fornecido pelo tratamento foi eficientemente absorvido pelos tecidos, mantendo os níveis de vitamina C cerca de 25% mais elevados nesses frutos do que nos demais tratamentos. A análise microbiológica detectou presença de bolores e leveduras e psicrotróficos, somente no tratamento com ácido cítrico, aos 8 e 10 dias, respectivamente. Não se detectaram coliformes totais e fecais e mesófilos, o que indica que o processamento foi realizado em boas condições higiênicas. Os kiwis minimamente processados e tratados com cloreto de cálcio apresentaram uma vida útil de dez dias. Nos demais tratamentos e no controle, esse tempo foi de seis dias.Minimally processed fruits and vegetables might present the same convenience and quality of fresh products. In this work, the influence of minimal processing of fruits treated with 1% solutions of ascorbic acid, citric acid and calcium chloride on the quality of kiwi (Actinidia deliciosa cv. Hayward, during refrigerated storage were investigated. Mass loss was minimal over the storage period. Ascorbic acid furnished by the treatment was effectively absorbed by tissues, keeping the vitamin C levels 25% higher in those fruits, than in other treatments. Microbiological analysis detected the presence of the group molds and yeasts and psychrotrophic in citric acid treatment, at 8 and 10 days, respectively. Total and faecal coliforms and mesophyles were not found, indicating that processing was performed under good hygienic conditions. Minimally

  10. Modelling the effect of ascorbic acid, sodium metabisulphite and sodium chloride on the kinetic responses of lactic acid bacteria and yeasts in table olive storage using a specifically implemented Quasi-chemical primary model.

    Science.gov (United States)

    Echevarria, R; Bautista-Gallego, J; Arroyo-López, F N; Garrido-Fernández, A

    2010-04-15

    The goal of this work was to apply the Quasi-chemical primary model (a system of four ordinary differential equations that derives from a hypothetical four-step chemical mechanism involving an antagonistic metabolite) in the study of the evolution of yeast and lactic acid bacteria populations during the storage of Manzanilla-Aloreña table olives subjected to different mixtures of ascorbic acid, sodium metabisulphite and NaCl. Firstly, the Quasi-chemical model was applied to microbial count data to estimate the growth-decay biological parameters. The model accurately described the evolution of both populations during storage, providing detailed information on the microbial behaviour. Secondly, these parameters were used as responses and analysed according to a mixture design experiment (secondary model). The contour lines of the corresponding response surfaces clearly disclosed the relationships between growth and environmental conditions, showing the stimulating and inhibitory effect of ascorbic acid and sodium metabisulphite, respectively, on both populations of microorganisms. This work opens new possibilities for the potential use of the Quasi-chemical primary model in the study of table olive fermentations.

  11. Characterization and fatty acid profiling in two fresh water microalgae for biodiesel production: Lipid enhancement methods and media optimization using response surface methodology.

    Science.gov (United States)

    Karpagam, Rathinasamy; Raj, Kalimuthu Jawahar; Ashokkumar, Balasubramaniem; Varalakshmi, Perumal

    2015-01-01

    Two fresh water microalgae, Coelastrella sp. M-60 and Micractinium sp. M-13 were investigated in this study for their potential of biodiesel production. For increasing biomass and lipid production, these microalgae were subjected to nutrient starvation (nitrogen, phosphorous, iron), salinity stress and nutrient supplementation with sugarcane industry effluent, citric acid, glucose and vitamin B12. The lipid productivity obtained from the isolates Coelastrella sp. M-60 (13.9 ± 0.4 mg/L/day) and Micractinium sp. M-13 (11.1 ± 0.2 mg/L/day) was maximum in salinity stress. The media supplemented with all the four nutrients yielded higher lipid productivity than the control. The response surface methodology (RSM) was employed to evaluate the effect of sugarcane industry effluent and citric acid on growth and lipid yield. Fatty acid profile of Coelastrella sp. M-60 and Micractinium sp. M-13 were composed of C-14, C-16:0, C-18:0, C-18:1 and C-18:2 and their fuel properties were also in accordance with international standards.

  12. S +X-I + route to mesostructured materials from Fau and Beta zeolite precursors: A comparative study of their assembly behaviors in extremely acidic media

    Science.gov (United States)

    Zheng, Junlin; Zhai, Shangru; Wu, Dong; Sun, Yuhan

    2005-05-01

    Mesoporous molecular sieves were synthesized from Beta and Fau zeolite precursors through S +X-I + route under extremely acidic conditions in parallel (designated as MBeta and MFau, respectively). The textural properties of MFau were different from its MBeta counterpart but resembled normal MCM-41 silica from TEOS. Al content in MBeta was almost equivalent to that in the initial Beta zeolite precursors, whereas only trace Al species was present in MFau from elemental analysis results. The hydrothermal stability of MBeta after post-synthesis ammonia treatment was considerably improved compared with normal MCM-41 aluminosilicates, whereas the MFau after the same procedure was as unstable as normal MCM-41 silica. Thus, the assembly behaviors of Beta and Fau zeolite precursors were comparatively studied based on these results. The microstructure of Fau zeolite precursors were degraded by the extremely acidic condition, and Al species was dissolved into the synthesis mixture. However, Beta zeolite precursors survived the chemical attack of extremely acidic media and were incorporated into mesostructured framework as primary building units.

  13. Mechanism of chloride interaction with neurotransmitter:sodium symporters.

    Science.gov (United States)

    Zomot, Elia; Bendahan, Annie; Quick, Matthias; Zhao, Yongfang; Javitch, Jonathan A; Kanner, Baruch I

    2007-10-11

    Neurotransmitter:sodium symporters (NSS) have a critical role in regulating neurotransmission and are targets for psychostimulants, anti-depressants and other drugs. Whereas the non-homologous glutamate transporters mediate chloride conductance, in the eukaryotic NSS chloride is transported together with the neurotransmitter. In contrast, transport by the bacterial NSS family members LeuT, Tyt1 and TnaT is chloride independent. The crystal structure of LeuT reveals an occluded binding pocket containing leucine and two sodium ions, and is highly relevant for the neurotransmitter transporters. However, the precise role of chloride in neurotransmitter transport and the location of its binding site remain elusive. Here we show that introduction of a negatively charged amino acid at or near one of the two putative sodium-binding sites of the GABA (gamma-aminobutyric acid) transporter GAT-1 from rat brain (also called SLC6A1) renders both net flux and exchange of GABA largely chloride independent. In contrast to wild-type GAT-1, a marked stimulation of the rate of net flux, but not of exchange, was observed when the internal pH was lowered. Equivalent mutations introduced in the mouse GABA transporter GAT4 (SLC6A11) and the human dopamine transporter DAT (SLC6A3) also result in chloride-independent transport, whereas the reciprocal mutations in LeuT and Tyt1 render substrate binding and/or uptake by these bacterial NSS chloride dependent. Our data indicate that the negative charge, provided either by chloride or by the transporter itself, is required during binding and translocation of the neurotransmitter, probably to counterbalance the charge of the co-transported sodium ions.

  14. Benzalkonium chloride and glaucoma.

    Science.gov (United States)

    Rasmussen, Carol A; Kaufman, Paul L; Kiland, Julie A

    2014-01-01

    Glaucoma patients routinely take multiple medications, with multiple daily doses, for years or even decades. Benzalkonium chloride (BAK) is the most common preservative in glaucoma medications. BAK has been detected in the trabecular meshwork (TM), corneal endothelium, lens, and retina after topical drop installation and may accumulate in those tissues. There is evidence that BAK causes corneal and conjunctival toxicity, including cell loss, disruption of tight junctions, apoptosis and preapoptosis, cytoskeleton changes, and immunoinflammatory reactions. These same effects have been reported in cultured human TM cells exposed to concentrations of BAK found in common glaucoma drugs and in the TM of primary open-angle glaucoma donor eyes. It is possible that a relationship exists between chronic exposure to BAK and glaucoma. The hypothesis that BAK causes/worsens glaucoma is being tested experimentally in an animal model that closely reflects human physiology.

  15. Metal-free N-doped carbon nanofibers as an efficient catalyst for oxygen reduction reactions in alkaline and acid media

    Science.gov (United States)

    Li, Ruchun; Shao, Xiaofeng; Li, Shuoshuo; Cheng, Pengpeng; Hu, Zhaoxia; Yuan, Dingsheng

    2016-12-01

    The development of metal-free catalysts to replace the use of Pt has played an important role in relation to its application to fuel cells. We report N-doped carbon nanofibers as the catalyst of an oxygen reduction reaction, which were synthesized via carbonizing bacterial cellulose-polypyrrole composites. The as-prepared material exhibited remarkable catalytic activity toward the oxygen reduction reaction with comparable onset potential and the ability to limit the current density of commercial Pt/C catalysts in both alkaline and acid media due to the unique porous three-dimensional network structure and the doped nitrogen atoms. The effect of N functionalities on catalytic behavior was systematically investigated. The results demonstrated that pyridinic-N was the dominating factor for catalytic performance toward the oxygen reduction reaction. Additionally, N-doped carbon nanofibers also demonstrated excellent cycling stability (93.2% and 89.4% retention of current density after chronoamperometry 20 000 s in alkaline and media, respectively), obviously superior to Pt/C.

  16. Increased axonal regeneration through a biodegradable amnionic tube nerve conduit: effect of local delivery and incorporation of nerve growth factor/hyaluronic acid media.

    Science.gov (United States)

    Mohammad, J A; Warnke, P H; Pan, Y C; Shenaq, S

    2000-01-01

    The authors emphasize the possible pharmacological enhancement of axonal regeneration using a specific growth factor/ extracellular media incorporated in a biodegradable nonneural nerve conduit material. They investigated the early effects on nerve regeneration of continuous local delivery of nerve growth factor (NGF) and the local incorporation of hyaluronic acid (HA) inside a newly manufactured nerve conduit material from fresh human amnionic membrane. Human amnionic membrane contains important biochemical factors that play a major neurotrophic role in the nerve regeneration process. The process of manufacturing a nerve conduit from fresh human amnionic membrane is described. This nerve conduit system was used in rabbits to bridge a 25-mm nerve gap over 3 months. NGF was released locally, over 28 days, at the distal end of the tube via a system of slow release, and HA was incorporated inside the lumen of the tube at the time of surgery. NGF/HA treatment promoted axonal regeneration across the amnionic tube nerve conduit (8,962 +/- 383 myelinated axons) 45% better than the nontreated amnionic tube group (6,180 +/- 353 myelinated axons). The authors demonstrate that NGF/HA media enhances additional axonal regeneration in the amnionic tube nerve conduit. This result is secondary to the effect of the amnion promoting biochemical factors, in combination with the NGF/HA effect on facilitating early events in the nerve regeneration process.

  17. Nitro radical anions from megazol and related nitroimidazoles in aprotic media. A father-son type reaction triggered by an acidic proton

    Energy Technology Data Exchange (ETDEWEB)

    Bonta, M.; Chauviere, G.; Perie, J.; Nunez-Vergara, L.J.; Squella, J.A

    2002-09-25

    We have studied the electrochemical reduction of some nitroimidazoles such as megazol(2-amino-5-(1-methyl-5-nitro-2-imidazolyl)-1,3,4-thiadiazol, CAS 19622-55-0) and two related derivatives in aprotic media (100% DMF, 0.1 M TBAP). All the studied compounds were easily reducible in aprotic media generating the corresponding nitro radical anions as products of the one electron reduction of the parent compound. The nitro radical anions decay by a dimerization reaction and the dimerization rate constants were obtained according to the Olmstead's approach by obtaining values of 150{+-}24, 1690{+-}42 and 640{+-}32 M{sup -1} s{sup -1} for megazol, GC-361 and GC-284, respectively. The existence of an acidic proton on the acetamide group in the GC-361 molecule triggered the appearance of father-son type reactions between the nitro radical anion from GC-361 (son compound) and GC-361 (father compound) generating the neutral radical and the conjugate base of GC-361. Thus the nitro radical anion from GC-361 acts as a Broensted base abstracting the proton of the acetamide group in the GC-361 derivative of megazol.

  18. The water soluble composite poly(vinylpyrrolidone–methylaniline: A new class of corrosion inhibitors of mild steel in hydrochloric acid media

    Directory of Open Access Journals (Sweden)

    R. Karthikaiselvi

    2017-02-01

    Full Text Available In recent years poly methyl aniline has been reported as one of the efficient corrosion inhibitors of mild steel in acidic media. In view of the major limitation of the insolubility of polymethyl aniline PMA, we propose to convert PMA into a water soluble composite using supporting polymer polyvinylpyrrolidone to get higher solubility and corrosion inhibition efficiency. The water soluble composite poly(vinylpyrrolidone-methyl aniline was synthesized by chemical oxidative polymerization and its inhibitive effect on mild steel in 1 M HCl has been investigated using weight loss and electrochemical techniques (potentiodynamic polarization studies and impedance spectroscopy. SEM and EDX analyses are carried out to establish a protective film formation on the metal surface.

  19. Polyethylene Glycols as Efficient Media for Decarboxylative Nitration of α,β-Unsaturated Aromatic Carboxylic Acids by Ceric Ammonium Nitrate in Acetonitrile Medium: A Kinetic and Mechanistic Study

    Directory of Open Access Journals (Sweden)

    K. Ramesh

    2013-01-01

    Full Text Available Polyethylene glycols (PEGs were found to be efficient media for decarboxylative nitration of α,β-unsaturated aromatic carboxylic acids by ceric ammonium nitrate (CAN in acetonitrile to give β-nitrostyrene derivatives. Kinetics of the reaction exhibited second order kinetics with a first order dependence on [CAN] and [substrate]. Reactions were too sluggish to be studied in the absence of PEG; therefore detailed kinetics were not taken up. Reaction times were reduced from 24 hrs to few hours. The catalytic activity was found to be in the increasing order PEG-300 > PEG-400 > PEG-600 > PEG-200. Mechanism of PEG-mediated reactions was explained by Menger-Portnoy's scheme as applied in micellar kinetics.

  20. Solid-phase extraction of cobalt(II) from lithium chloride solutions using a poly(vinyl chloride)-based polymer inclusion membrane with Aliquat 336 as the carrier.

    Science.gov (United States)

    Kagaya, Shigehiro; Cattrall, Robert W; Kolev, Spas D

    2011-01-01

    The extraction of cobalt(II) from solutions containing various concentrations of lithium chloride, hydrochloric acid, and mixtures of lithium chloride plus hydrochloric acid is reported using a poly(vinyl chloride) (PVC)-based polymer inclusion membrane (PIM) containing 40% (w/w) Aliquat 336 as a carrier. The extraction from lithium chloride solutions and mixtures with hydrochloric acid is shown to be more effective than extraction from hydrochloric acid solutions alone. The solution concentrations giving the highest amounts of extraction are 7 mol L(-1) for lithium chloride and 8 mol L(-1) lithium chloride plus 1 mol L(-1) hydrochloric acid for mixed solutions. Cobalt(II) is easily stripped from the membrane using deionized water. The cobalt(II) species extracted into the membrane are CoCl(4)(2-) for lithium chloride solutions and HCoCl(4)(-) for mixed solutions; these form ion-pairs with Aliquat 336. It is also shown that both lithium chloride and hydrochloric acid are extracted by the PIM and suppress the extraction of cobalt(II) by forming ion-pairs in the membrane (i.e. R(3)MeN(+)·HCl(2)(-) for hydrochloric acid and R(3)MeN(+)·LiCl(2)(-) for lithium chloride).

  1. Formation processes of CuCl and regenerated Cu crystals on bronze surfaces in neutral and acidic media

    Energy Technology Data Exchange (ETDEWEB)

    Wang Julin [Institute of Materials Science and Engineering, Beijing University of Chemical Technology, Beijing 100029 (China)]. E-mail: julinwang@126.com; Xu Chunchun [Institute of Materials Science and Engineering, Beijing University of Chemical Technology, Beijing 100029 (China); Lv Guocheng [Institute of Materials Science and Engineering, Beijing University of Chemical Technology, Beijing 100029 (China)

    2006-07-15

    The paper is devoted to investigating the formation of CuCl and regenerated Cu crystals on bronze. Electrochemical behaviour of bronze in simulated anoxic edaphic media and occluded cell (O.C.) solutions was studied with cycle voltammetry (CV) and X-ray diffraction (XRD). Within potential range of -800 to +800 mV, oxidation occurred was largely a process in which Cu is oxidized to CuCl and the reduction process was a reverse of it. An atomic force microscopy (AFM) was used to observe the morphology of CuCl crystals, regenerated Cu crystals and corrosion interface at nm level. The deposition of regenerated Cu on simulated archaeological bronzes was simulated under experimental conditions for the first time. CuCl could be thoroughly reduced to pure Cu if reduction time interval were sufficiently prolonged. This provided a theoretical and experimental basis for getting rid of harmful CuCl patina from archaeological bronzes with electrochemical means.

  2. Acidity and complex formation studies of 3-(adenine-9-yl)-propionic and 3-(thymine-1-yl)-propionic acids in ethanol-water media

    Science.gov (United States)

    Hammud, Hassan H.; El Shazly, Shawky; Sonji, Ghassan; Sonji, Nada; Bouhadir, Kamal H.

    2015-05-01

    The ligands 3-(adenine-9-yl)propionic acid (AA) and 3-(thymine-1-yl)propionic acid (TA) were prepared by N9-alkylation of adenine and N1-alkylation of thymine with ethylacrylate in presence of a base catalyst, followed by acid hydrolysis of the formed ethyl esters to give the corresponding propionic acid derivatives. The products were characterized by spectral methods (FTIR, 1H NMR and 13C NMR), which confirm their structures. The dissociation constants of ligands, were potentiometrically determined in 0.3 M KCl at 20-50 °C temperature range. The work was extended to study complexation behavior of AA and TA with various biologically important divalent metal ions (Co2+, Ni2+, Cu2+, Zn2+, Cd2+, Mn2+ and Pb2+) in 50% v/v water-ethanol medium at four different temperatures, keeping ionic strength constant (0.3 M KCl). The order of the stability constants of the formed complexes decreases in the sequence Cu2+ > Pb2+ > Zn2+ > Ni2+ > Co2+ > Mn2+ > Cd2+ for both ligands. The effect of temperature was also studied and the corresponding thermodynamic functions (ΔG, ΔH, ΔS) were derived and discussed. The formation of metal complexes has been found to be spontaneous, and the stability constants were dependant markedly on the basicity of the ligands.

  3. A chloride ion nanosensor for time-resolved fluorimetry and fluorescence lifetime imaging.

    Science.gov (United States)

    Ruedas-Rama, Maria J; Orte, Angel; Hall, Elizabeth A H; Alvarez-Pez, Jose M; Talavera, Eva M

    2012-03-21

    In this work, the first CdSe/ZnS quantum dot (QD) photoluminescence lifetime based chloride ion nanosensor is reported. The acridinium dication lucigenin was self-assembled on the surface of negatively charged mercaptopropionic acid capped QDs to achieve QD-lucigenin conjugates. Upon attachment, a drastic decrease of the photoluminescence lifetime of both QD nanoparticles and lucigenin is observed by virtue of a charge transfer mechanism. Since lucigenin is a chloride-sensitive indicator dye, the photoluminescence decay of QD-lucigenin conjugates changes by adding chloride ion. The photoluminescence lifetime of the QDs in the conjugate increases after reacting with Cl(-), but also shows a concomitant decrease in the lucigenin lifetime immobilized on the surface. The photoluminescence lifetime of QD-lucigenin nanosensors shows a linear response in the Cl(-) concentration range between 0.5 and 50 mM. Moreover, the ratio τ(ave)(QD)/τ(ave)(luc) can be used as an analytical signal since the lifetime ratio presents a linear response in the same Cl(-) concentration range. The system also shows good selectivity towards most of the main anions and molecules that can be found in biological fluids. These nanosensors have been satisfactorily applied for Cl(-) determination in simulated intracellular media with high sensitivity and high selectivity. Finally, we demonstrate the potential application of the proposed nanosensor in confocal fluorescence lifetime imaging (FLIM). These results show the promising application of the QD-lucigenin nanosensors in FLIM, particularly for intracellular sensing, with the invaluable advantages of the time-resolved fluorescence techniques.

  4. Liquid-Phase Beckmann Rearrangement of Cyelohexanone Oxime Catalyzed by Acidic Ionic Liquid-Zinc Chloride%酸性离子液体-ZnCl2催化环己酮肟液相Beckmann重排反应

    Institute of Scientific and Technical Information of China (English)

    赵江琨; 王荷芳; 王延吉; 赵新强; 张宝泉

    2011-01-01

    在乙腈介质中,由酸性离子液体和ZnCl2组成的催化体系,可以高效地实现对环己酮肟液相Beckmann重排制己内酰胺的反应.反应过程中生成的唯一副产物环己酮,可以通过氨氧化反应生成原料环己酮肟.考察了溶剂种类、反应温度、反应时间、离子液体用量和ZnCl2用量对环己酮肟重排反应性能的影响.确定了适宜的反应条件;HSO3-b-N(CH)3]HSO4 0.5 mmol,ZnCl2 15 mmol,乙腈10 mL,环己酮肟10 mmol,反应温度80℃,反应时间4h.此条件下,环己酮肟转化率达100%,己内酰胺收率为94.9%.利用在线反应红外光谱仪(React IR IC-10)研究了该催化体系下环己酮肟重捧反应机理.%The liquid-phase Beckmann rearrangement of cyclohexanone oxime was effectively realized to prepare e-caprolactam by using acidic ionic liquid-zinc chloride(IL-ZnCl2) catalytic system in acetonitrile. The only by-product, cyclohexanone, could convert back to the raw material, cyclohexanone oxime, by ammoximation reactionThe effects of solvents, reaction temperature, reaction time, the amount of IL, the amount of ZnCl2 on the Beckmann rearrangement were studied. The optimized conditions were:[HSO3-b-N(CH3)3]HSO4 0.5mmol, ZnCl2 15 mmol, acetonitrile 10 mL, cyclohexanone oxime 10 mmol, 80℃, 4 h. The conversation of cyclohexanone oxime can reach 100%, the yield of e-caprolactam can reach 94.9%.The reaction mechanism of cyclohexanone oxime rearrangement over IL-ZnCl2 catalyst was also investigated by React IR IC-10.

  5. Effect of Gibberellic Acid and Choline Chloride on the Growth Indexes of Eucalyptu urophylla Seedling%赤霉素和氯化胆碱对尾叶桉幼苗生长指标的影响

    Institute of Scientific and Technical Information of China (English)

    邓福春; 韦泳丽; 杨振德; 翟明普

    2012-01-01

    采用盆栽方法,把赤霉素和氯化胆碱2种生长调节剂添加到富含微量元素的生物活性肥中,探讨这种复合制剂处理对尾叶桉幼苗生长的影响,为桉树生长调控和人工林精准化栽培提供理论依据。结果表明:喷施Lc复合药荆对尾叶桉幼苗的生长、根系的发育具有明显的促进作用。幼苗的株高、地径、生物量的增长分别比对照大36.7cm、0.25cm、3g,经方差分析均有显著差异(P〈0.05)。与对照相比,根冠比增加19.07%。Lc复合药剂处理后桉幼苗的分支数有所减少,但与对照相比没有显著差异(P〉0.05)。此外,Lc复合药剂具有促使生物量优先分配到茎干的作用。%Pot experiment was used to study the effect of complex preparation on the growth of Euca- lyptu urophylla seedling, which added the gibberellic acid and choline chloride to the biological active fertilizer rich in trace elements. This was aimed to provide the theoretical basis for eucalyptus growth regulation and accurated cultivation technology of eucalyptus plantation. The results showed that Lc treatment could remarkably improve the growth of seedling and root system. Height, ground diameter and biomass of E. urophylla seedlings increased by 36.7 cm, 0.25 cm, 3 g more than the control (P 〈 0.05) respectively. Compared with control, root-shoot ratio increased by 19.07 %. Meanwhile, branch number of E. urophylla seedlings after treating by Lc complex preparation decreased, but not significant compared with control group ( P〉0.05 ). In addition, Lc treatment could promote biomass to preferably be distributed into stem.

  6. Physicochemical properties and ecotoxicological effects of yttrium oxide nanoparticles in aquatic media: Role of low molecular weight natural organic acids.

    Science.gov (United States)

    Zhang, Fan; Wang, Zhuang; Wang, Se; Fang, Hao; Chen, Mindong; Xu, Defu; Tang, Lili; Wang, Degao

    2016-05-01

    Understanding how engineered nanoparticles (ENPs) interact with natural organic acids is important to ecological risk assessment of ENPs, but this interaction remains poorly studied. Here, we investigate the dispersion stability, ion release, and toxicity of yttrium oxide nanoparticles (nY2O3) suspensions after exposure to two low molecular weight natural organic acids (LOAs), namely benzoic acid and gallic acid. We find that in the presence of LOAs the nY2O3 suspensions become more stable with surface zeta potential more positive or negative, accompanied by small agglomerated size. LOA interaction with nY2O3 is shown to promote the release of dissolved yttrium from the nanoparticles, depending on the concentrations of LOAs. Toxic effects of the nY2O3 suspensions incubated with LOAs on Scenedesmus obliquus as a function of their mixture levels show three types of signs: stimulation, inhibition, and alleviation. The mechanism of the effects of LOAs on the nY2O3 toxicity may be mainly associated with the degree of agglomeration, particle-induced oxidative stress, and dissolved yttrium. Our results stressed the importance of LOA impacts on the fate and toxicity of ENPs in the aquatic environment. Copyright © 2016 Elsevier Ltd. All rights reserved.

  7. Lewis acid catalyzed ring-opening polymerization of natural epoxy oil (Euphorbia oil) in carbon dioxide media

    Science.gov (United States)

    In an attempt to build up useful application of plant oil based polymers, natural epoxy oil (euphorbia oil-EuO) was polymerized in liquid carbon dioxide in the presence of Lewis acid catalyst [Boron trifluoride diethyl etherate (BF3•OEt2)]. The resulting polymers (RPEuO) were characterized by FTIR ...

  8. Microwave promoted rapid dehydration of aldoximes to nitrites using melamine-formaldehyde resin supported sulphuric acid in dry media

    Institute of Scientific and Technical Information of China (English)

    Ramin Rezaei; Marzeih Karami

    2011-01-01

    A simple and convenient procedure for the synthesis of nitriles by dehydration of aldoxime using supported sulphuric acid on melamine-formaldehyde resin (MFR) under solvent-free condition has been developed. A variety of aromatic and aliphatic aldoximes were converted to the corresponding nitriles. The resin was recovered and reused for subsequent reactions.

  9. Optimization of Brewery's spent grain dilute-acid hydrolysis for the production of pentose-rich culture media.

    Science.gov (United States)

    Carvalheiro, Florbela; Duarte, Luís C; Medeiros, Raquel; Gírio, Francisco M

    2004-01-01

    Dilute-acid hydrolysis of brewery's spent grain to obtain a pentose-rich fermentable hydrolysate was investigated. The influence of operational conditions on polysaccharide hydrolysis was assessed by the combined severity parameter (CS) in the range of 1.39-3.06. When the CS increased, the pentose sugars concentration increased to a maximum at a CS of 1.94, whereas the maximum glucose concentration was obtained for a CS of 2.65. The concentrations of furfural, hydroxymethylfurfural (HMF), as well as formic and levulinic acids and total phenolic compounds increased with severity. Optimum hydrolysis conditions were found at a CS of 1.94 with >95% of feedstock pentose sugars recovered in the monomeric form, together with a low content of furfural, HMF, acetic and formic acids, and total phenolic compounds. This hydrolysate containing glucose, xylose, and arabinose (ratio 10:67:32) was further supplemented with inorganic salts and vitamins and readily fermented by the yeast Debaryomyces hansenii CCMI 941 without any previous detoxification stage. The yeast was able to consume all sugars, furfural, HMF, and acetic acid with high biomass yield, 0.68 C-mol/C-mol, and productivity, 0.92 g/(L.h). Detoxification with activated charcoal resulted in a similar biomass yield and a slight increase in the volumetric productivity (11%).

  10. Synthesis of Poly(methacrylic acid)-functionalized SBA-15 and its Adsorption of Phenol in Aqueous Media

    Energy Technology Data Exchange (ETDEWEB)

    Vo, Vien; Kim, Heejun; Kim, Hayeong; Kim, Youngmee; Kim, Sung Jin [Ewha Womans Univ., Seoul (Korea, Republic of)

    2013-12-15

    Poly(methacrylic acid)-functionalized SBA-15 silicas (denoted as P-x-PMA/SBA-15 where x is molar ratio of TSPM/(TEOS+TSPM) in percentage in the initial mixture) were synthesized by co-condensation of tetraethoxysilane and varying contents of 3-(trimethoxysilyl)propyl methacrylate in acidic medium with the block copolymer Pluronic 123 as a structure directing agent and then polymerization by methacrylic acid in the presence of ammonium persulfate as an initiator. The functionalized materials were characterized by PXRD, TEM, SEM, IR, and N{sub 2} adsorption-desorption at 77 K. The investigation of phenol adsorption in aqueous solution on the materials showed that the poly(methacrylic acid)-functionalized mesoporous silicas possess strong adsorption ability for phenol with interaction of various kinds of hydrogen bonds. The adsorption data were fitted to Langmuir isotherms and the maximum adsorption capacity of the three functionalized materials P-5-PMA/SBA-15, P-10-PMA/SBA-15, and P-15-PMA/SBA-15 to be 129.37 mg/g, 187.97 mg/g, and 78.43 mg/g, respectively, were obtained. The effect of the pH on phenol adsorption was studied.

  11. Perfluorinated carboxylic and sulphonic acids in surface water media from the regions of Tibetan Plateau: Indirect evidence on photochemical degradation?

    Science.gov (United States)

    Yamazaki, Eriko; Falandysz, Jerzy; Taniyasu, Sachi; Hui, Ge; Jurkiewicz, Gabriela; Yamashita, Nobuyoshi; Yang, Yong-Liang; Lam, Paul K S

    2016-01-01

    Perfluorinated surfactants and repellents are synthetic substances that have found numerous industrial and customer applications. Due to their persistence, at least two groups of these substances-perfluorinated carboxylic acids (PFCAs) and perfluorinated sulfonic acids (PFSAs)-are diffused widely in the environment. It is hypothesized that the Tibetan Plateau, is one of few unique places on the Earth, due to its topography, specifically the vast space and high elevation above sea level, geographic location, climate, high solar radiation, lack of industry, little urbanization and general lack of significant direct sources of pollution. There it is believed possible to gain an insight into atmospheric fate (possible photochemical degradation of higher molecular mass and formation of lower molecular mass PFCAs and PFSAs) of PFASs under un-disturbed environmental conditions. Ultratrace analytical method for PFCAs and PFSAs and use of transportation and field blanks, laboratory blanks and isotopically labelled surrogates for recovery control has allowed the determination of nine perfluorinated carboxylic acids and six perfluorinated sulfonic acids at ultra-trace levels in water based samples from the alpine dimension regions of the Tibetan Plateau, the eastern slope of Minya Konka peak at the eastern edge of the Tibetan Plateau, and also from the city of Chengdu from the lowland of the Sichuan Province in China. The specific compositional pattern of PFCAs and PFSAs and low levels of pollution with those compounds were observed in the central region of the Tibetan Plateau and in the region adjacent to the peaks of Minya Konka in the Eastern Tibetan Plateau. The fingerprint of the compositional pattern of PFCAs and PFSAs in water samples in the central region of the Tibetan Plateau and in the alpine region adjacent to the peaks of Minya Konka in the Eastern Tibetan Plateau may be explained by the result of photochemical degradation with dealkylation of longer chain

  12. Carbonate and Chloride Scavenging in S2O82-/Fe2+/Citric Acid Oxidation of PCE

    DEFF Research Database (Denmark)

    Bennedsen, Lars Rønn; Søgaard, Erik Gydesen; Mortensen, Lars

    contaminants are not widely investigated or well understood, but it is assumed that they have an overall negative impact on performance (Liang, Wang & Mohanty 2006; Huang, Couttenye & Hoag 2002). High concentrations of chloride have also been reported to result in formation of halogenated by-products (Aiken...

  13. Electrochemical activity of heavy metal oxides in the process of chloride induced corrosion of steel reinforcement

    Indian Academy of Sciences (India)

    V Živica

    2002-10-01

    The influence of heavy metal oxides on the chloride induced corrosion of steel reinforcement in concrete was studied. Significant inhibition and stimulation of chloride induced corrosion have been observed. Basicity and acidity of the relevant metal ions, and their ability to form complexes are considered as the main factors of the observed effects.

  14. Media education.

    Science.gov (United States)

    Strasburger, Victor C

    2010-11-01

    The American Academy of Pediatrics recognizes that exposure to mass media (eg, television, movies, video and computer games, the Internet, music lyrics and videos, newspapers, magazines, books, advertising) presents health risks for children and adolescents but can provide benefits as well. Media education has the potential to reduce the harmful effects of media and accentuate the positive effects. By understanding and supporting media education, pediatricians can play an important role in reducing harmful effects of media on children and adolescents.

  15. Corrosion of reinforcement induced by environment containing chloride and carbon dioxide

    Indian Academy of Sciences (India)

    Vladimír Živica

    2003-10-01

    Reinforced concrete structures during their exploitation may be exposed to the common action of carbonation and chlorides causing corrosion of steel reinforcement. Therefore, the related data seem to be interesting and important when the evaluation of the service life of the structures is the object of interest. This fact was a motivation for the present experimental study on the sequence of action of chloride solutions and carbonation of the embedding concrete. The results obtained show that carbonation of concrete foregoing the action of chloride solutions may intensify the process of corrosion of steel reinforcement in comparison to the converse sequence of the action of mentioned media. At the same time the natrium chloride solution has been shown as a more aggressive medium opposite to the calcium and magnesium chloride solutions.

  16. The complete genome sequence of Natrinema sp. J7-2, a haloarchaeon capable of growth on synthetic media without amino acid supplements.

    Directory of Open Access Journals (Sweden)

    Jie Feng

    Full Text Available Natrinema sp. J7-2 is an extreme haloarchaeon capable of growing on synthetic media without amino acid supplements. Here we report the complete genome sequence of Natrinema sp. J7-2 which is composed of a 3,697,626-bp chromosome and a 95,989-bp plasmid pJ7-I. This is the first complete genome sequence of a member of the genus Natrinema. We demonstrate that Natrinema sp. J7-2 can use gluconate, glycerol, or acetate as the sole carbon source and that its genome encodes complete metabolic pathways for assimilating these substrates. The biosynthetic pathways for all 20 amino acids have been reconstructed, and we discuss a possible evolutionary relationship between the haloarchaeal arginine synthetic pathway and the bacterial lysine synthetic pathway. The genome harbors the genes for assimilation of ammonium and nitrite, but not nitrate, and has a denitrification pathway to reduce nitrite to N(2O. Comparative genomic analysis suggests that most sequenced haloarchaea employ the TrkAH system, rather than the Kdp system, to actively uptake potassium. The genomic analysis also reveals that one of the three CRISPR loci in the Natrinema sp. J7-2 chromosome is located in an integrative genetic element and is probably propagated via horizontal gene transfer (HGT. Finally, our phylogenetic analysis of haloarchaeal genomes provides clues about evolutionary relationships of haloarchaea.

  17. Neuronal chloride accumulation and excitatory GABA underlie aggravation of neonatal epileptiform activities by phenobarbital.

    Science.gov (United States)

    Nardou, Romain; Yamamoto, Sumii; Chazal, Geneviève; Bhar, Asma; Ferrand, Nadine; Dulac, Olivier; Ben-Ari, Yehezkel; Khalilov, Ilgam

    2011-04-01

    Phenobarbital produces its anti-epileptic actions by increasing the inhibitory drive of γ-aminobutyric acid. However, following recurrent seizures, γ-aminobutyric acid excites neurons because of a persistent increase of chloride raising the important issue of whether phenobarbital could aggravate persistent seizures. Here we compared the actions of phenobarbital on initial and established ictal-like events in an in vitro model of mirror focus. Using the in vitro three-compartment chamber preparation with the two hippocampi and their commissural fibres placed in three different chambers, kainate was applied to one hippocampus and phenobarbital contralaterally, either after one ictal-like event or after many recurrent ictal-like events that produce an epileptogenic mirror focus. Field, perforated patch and single-channel recordings were used to determine the effects of γ-aminobutyric acid and their modulation by phenobarbital, and alterations of the chloride cotransporters were investigated using sodium-potassium-chloride cotransporter 1 and potassium chloride cotransporter 2 antagonists, potassium chloride cotransporter 2 immunocytochemistry and sodium-potassium-chloride cotransporter 1 knockouts. Phenobarbital reduced initial ictal-like events and prevented the formation of a mirror focus when applied from the start. In contrast, phenobarbital aggravated epileptiform activities when applied after many ictal-like events by enhancing the excitatory actions of γ-aminobutyric acid due to increased chloride. The accumulation of chloride and the excitatory actions of γ-aminobutyric acid in mirror foci neurons are mediated by the sodium-potassium-chloride cotransporter 1 chloride importer and by downregulation and internalization of the chloride-exporter potassium-chloride cotransporter 2. Finally, concomitant applications of the sodium-potassium-chloride cotransporter 1 antagonist bumetanide and phenobarbital decreased excitatory actions of γ-aminobutyric acid and

  18. A contribution to the study of thorium and neptunium (IV) complexes in acidic phosphoric media; Contribution a l`etude des complexes de thorium et de neptunium (IV) en milieux phosphoriques acides

    Energy Technology Data Exchange (ETDEWEB)

    Ghafar, M.

    1995-11-30

    The thorium and neptunium (IV) phosphate complexes formation in acidic media has been investigated, essentially at the indicator`s level with {sup 227} Th, {sup 234} Th, {sup 235} Np and {sup 239} Np. Solvent extraction, a commonly used method for determining stability constants in solutions, was used with HDEHP in toluene. In order to get a better understanding of inorganic transparent gels formation in phosphoric aqueous solutions, the effect of the thorium concentration is also studied. Specific experimental conditions have been chosen in order to avoid the formation of chelate and hydrolysis in the aqueous solution. The equilibrium constants and stability constants are calculated, and the results are compared with literature. The results show that increasing the thorium concentration does not lead to polymer forms. refs., 42 figs., 19 tabs.

  19. Inhibition of Clostridium botulinum 52A toxicity and protease activity by sodium acid pyrophosphate in media systems.

    OpenAIRE

    Wagner, M.K.; Busta, F. F.

    1985-01-01

    The effects of two pH levels (5.55 or 5.85) in combination with 0.4% sodium acid pyrophosphate (SAPP), NaH2PO4 X H2O, Na2HPO4 X 7H2O, or NaCl on the growth and toxicity of Clostridium botulinum 52A were studied. Absorbancy measurements at 630 nm, microscopic observations, and the mouse bioassay procedure were used to observe the effects. At pH 5.55 and 5.85 most control cultures exhibited toxicity when cell lysis began. Vegetative cell development was normal (4 micron long; 1 micron wide). SA...

  20. Toward an Active and Stable Catalyst for Oxygen Evolution in Acidic Media: Ti-Stabilized MnO2

    DEFF Research Database (Denmark)

    Frydendal, Rasmus; Paoli, Elisa Antares; Chorkendorff, Ib;

    2015-01-01

    Catalysts are required for the oxygen evolution reaction, which are abundant, active, and stable in acid. MnO2 is a promising candidate material for this purpose. However, it dissolves at high overpotentials. Using first-principles calculations, a strategy to mitigate this problem by decorating...... undercoordinated surface sites of MnO2 with a stable oxide is developed here. TiO2 stands out as the most promising of the different oxides in the simulations. This prediction is experimentally verified by testing sputter-deposited thin films of MnO2 and Ti-MnO2. A combination of electrochemical measurements...