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Sample records for acid edta complex

  1. Role of ethylene diamine tetra-acetic acid (EDTA) in catheter lock solutions: EDTA enhances the antifungal activity of amphotericin B lipid complex against Candida embedded in biofilm.

    PubMed

    Raad, Issam I; Hachem, Ray Y; Hanna, Hend A; Fang, Xiang; Jiang, Ying; Dvorak, Tanya; Sherertz, Robert J; Kontoyiannis, Dimitrios P

    2008-12-01

    Ethylene diamine tetra-acetic acid (EDTA) is an anticoagulant with antibiofilm-enhancing activity. We therefore used an in vitro biofilm model to determine the activity of amphotericin B lipid complex (ABLC) with or without EDTA against Candida embedded in biofilm on silicone disk surfaces. Clinical blood isolates from cancer patients infected with Candida albicans or Candida parapsilosis were used. Silicone disks were colonised with C. albicans or C. parapsilosis and were sequentially incubated in plasma and then in Mueller-Hinton broth containing 10(5) colony-forming units of each organism. All tests were performed in triplicate. The disks were subsequently placed and incubated for 6h and 8h in solutions containing ABLC alone, EDTA alone, ABLC+EDTA or broth (control). Disks were then removed, sonicated and colony counts were determined. ABLC+EDTA (30 mg/mL) was significantly more effective than ABLC, EDTA and control against C. parapsilosis at 6h (P < or = 0.01) and against C. albicans at 8h (P < or = 0.04). In patients with catheter-related candidaemia when catheter removal is not feasible, the combination of ABLC+EDTA may be considered for antifungal catheter lock solution as part of a catheter salvage therapy. PMID:18783924

  2. Analysis of metal-EDTA complexes by electrospray mass spectrometry

    SciTech Connect

    Baron, D.; Hering, J.G.

    1998-07-01

    Solutions of the strong complexing agent ethylenediaminetetraacetic acid (EDTA) and Cu, Pb, Cd, Al, and Fe(III) were examined by electrospray mass spectrometry (ES/MS). Uncomplexed EDTA and metal-EDTA complexes survive the electrospray process intact and can be detected simultaneously by mass spectrometry. Best sensitivity was achieved in the positive ion mode in which EDTA and EDTA-metal complexes (present in solution as anions) were detected as protonated species with a single positive charge. Except for the protonation, the aqueous metal-EDTA complexes are preserved and neither fragmentation of complexes nor formation of clusters with more than one metal or ligand were observed in the mass spectra. Detection limits are between approximately 1 to 2 {micro}M for uncomplexed EDTA and for the Cu-EDTA and Pb-EDTA complexes, with a linear range up to 10{sup {minus}4} M. Calibrations based on solutions with equimolar concentrations of EDTA and Cu or Pb can be used to quantify EDTA-metal complexes in solutions with excess EDTA or metal, and in solutions with more than one metal present. Isotopic signatures of metals in the metal-ligand complexes are preserved, allowing the identification of the metal in a metal-ligand complex. Isotopic signatures of metals can therefore aid in the identification of metal-ligand complexes in unknown samples.

  3. An Aqueous Thermodynamic Model for the Complexation of Sodium and Strontium with Organic Chelates valid to High Ionic Strength. I. Ethylenedinitrilotetraacetic acid (EDTA)

    SciTech Connect

    Felmy, Andrew R.; Mason, Marvin J.

    2003-04-01

    An aqueous thermodynamic model is developed, which accurately describes the effects of Na+ complexation, ionic strength, carbonate concentration, and temperature on the complexation of Sr2+ by ethylenedinitrilotetraacetic acid (EDTA) under basic conditions. The model is developed from the analysis of literature data on apparent equilibrium constants, enthalpies, and heat capacities; as well as on an extensive set of solubility data on SrCO3(c) in the presence of EDTA obtained as part of this study. The solubility data for SrCO3(c) were obtained in solutions ranging in Na2CO3 concentration from 0.01m to 1.8m, in NaNO3 concentration from 0 to 5m, and at temperatures extending to 75?C. The final aqueous thermodynamic model is based upon the equations of Pitzer and requires the inclusion of a NaEDTA3- species. An accurate model for the ionic strength dependence of the ion-interaction coefficients for the SrEDTA2- and NaEDTA3- aqueous species allows the extrapolation of standard state equilibrium constants for these species which are significantly different from the 0.1m reference state values available in the literature. The final model is tested by application to chemical systems containing competing metal ions (i.e., Ca2+) to further verify the proposed model and indicate the applicability of the model parameters to chemical systems containing other divalent metal-EDTA complexes.

  4. Potentiometry: A Chromium (III) -- EDTA Complex

    ERIC Educational Resources Information Center

    Hoppe, J. I.; Howell, P. J.

    1975-01-01

    Describes an experiment that involves the preparation of a chromium (III)-EDTA compound, a study of its infrared spectrum, and the potentiometric determination of two successive acid dissociation constants. (Author/GS)

  5. Biocompatibility of EDTA, EGTA and citric acid.

    PubMed

    Sousa, Simone Maria Galvão de; Bramante, Clovis Monteiro; Taga, Eulázio Mikio

    2005-01-01

    This in vivo study evaluated, through the physicochemical assay method for quantification of enhanced vascular permeability, the irritating potential of EDTA, EGTA, citric acid and saline. Thirty-two male Wister rats were anesthetized and four experimental sites were demarcated on their backs. Injections of 2% Evans blue (20 mg/kg) were administered intravenously into the lateral caudal vein. The test solutions were immediately injected intradermally (0.01 mL) into the experimental sites. The animals were killed 30 min, 1, 3 and 6 h after injection of the solutions and each piece of skin was submerged in formamide and incubated at 45 masculineC for 72 h. After filtration, the optical density was measured in a spectrophotometer and the total amount of dye extracted from the samples was calculated by means of a standard calibration curve. Data were analyzed statistically by two-way ANOVA and Tukey's HSD test. Compared to control, EDTA had the greatest volume of dye followed by EGTA and citric acid, for all time periods. There were statistically significant differences between all solutions (p<0.01). Considering the periods assessed, a significant difference was observed between the 3- and 6-h groups (p<0.05), but not between the 30-min and 1-h groups. Among the organic acids evaluated in this study, citric acid yielded the lowest amount of extracted dye. This indicates that the citric acid was the least irritating solution.

  6. Direct analysis of ethylenediaminetetraacetic acid (EDTA) on concrete by reactive-desorption electrospray ionization mass spectrometry.

    PubMed

    Lebeau, D; Reiller, P E; Lamouroux, C

    2015-01-01

    Analysis of organic ligands such as ethylenediaminetetraacetic acid (EDTA) is today an important challenge due to their ability to increase the mobility of radionuclides and metals. Reactive desorption electrospray ionization mass spectrometry (reactive-DESI-MS) was used for direct analysis of EDTA on concrete samples. EDTA forms complexes and those with Fe(III) ions are among the most thermodynamically favored. This complexing capacity was used to improve the specific detection of EDTA directly on a concrete matrix by doping the solvent spray of DESI with a solution of FeCl3 to selectively create the complex between EDTA and Fe(III). Thus, EDTA sensitivity was largely improved by two orders of magnitude with reactive-DESI-MS experiments thanks to the specific detection of EDTA as a [EDTA-4H+Fe(III)](-) complex. The proof of principle that reactive DESI can be applied to concrete samples to detect EDTA has been demonstrated. Its capacity for semi-quantitative determination and localization of EDTA under ambient conditions and with very little sample preparation, minimizing sample manipulations and solvent volumes, two important conditions for the development of new methodologies in the field of analytical chemistry, has been shown.

  7. [Cd uptake in rice cultivars and Cd fractions in soil treated with organic acids and EDTA].

    PubMed

    Zhang, Hai-Bo; Li, Yang-Rui; Xu, Wei-Hong; Chen, Gui-Qing; Wang, Hui-Xian; Han, Gui-Qi; Zhang, Xiao-Jing; Xiong, Zhi-Ting; Zhang, Jin-Zhong; Xie, De-Ti

    2011-09-01

    A pot experiment was conducted to examine the yield, quality and cadmium (Cd) uptake in different rice cultivars, and Cd speciation in soil after exposing to Cd (0, 1 and 5 mg x kg(-1)) in the presence of organic acids and ethylenediamine tetraacetic acid (EDTA). The results showed that general increase in the yield for cultivars Xiushui63 and II you527 was observed. Yield of two rice cultivars were in order of organic acids treatment or organic acids + 1/2EDTA treatment > EDTA treatment. The exchangeable, carbonate related and ferric-manganese oxidation related Cd increased; while organic complexation Cd and residules decreased in the presence of organic acids and EDTA. Cadmium concentrations in grain, straw and roots of both cultivars markedly reduced in the presence of organic acids and EDTA. Grain Cd concentration was the lowest for plants treated with EDTA, followed by organic acids + 1/2EDTA, and the highest Cd concentration in grain was found in the treatment with organic acids. Grain Cd concentration decreased by 9.0% to 49.3% and 16.5% to 30.6% at 1 mg x kg(-1) Cd in the presence of organic acids and EDTA, and by 12.7% to 28.5% and 4.3% to 19.1% at 5 mg x kg(-1) Cd. Cadmium concentration and accumulation in plants and total Cd content in soil were higher in Xiushui63 than in that in II you527. Grain Cd concentration decreased, and yield and quality of two rice cultivars increased at the same time in the presence of organic acids + 1/2EDTA.

  8. Electrochemical study of NO conversion from Fe(II)-EDTA-NO complex on Pt electrodes

    SciTech Connect

    Juzeliunas, E.; Juettner, K.

    1998-01-01

    The Fe(II)-ethylenediaminetetraacetic acid (EDTA)-NO complex formed by interaction of gaseous nitrous oxide (ca. 200 ppm) and Fe(II)-EDTA in aqueous solution was found to be convert3ed electrochemically on platinum electrodes at potentials below ca. {minus}0.6 V{sub SCE}, indicating the cathodic reduction of NO. In addition to the previous studies by which the indirect conversion of NO with dithionite as a redox mediator was confirmed, the present results should elucidate the possibility of the direct electrochemical conversion of NO in mediator-free solutions. To clearly separate this process from other reactions in the system, the electrochemical behavior of Fe(II)-EDTA and Fe(III)-EDTA was studied over a wide potential range at different pH values. Five electrode reactions could be identified, which include the oxidation/reduction of Fe{sup 2+}/Fe{sup 3+} in the EDTA complex, the reduction of EDTA, the reduction of protons, the cathodic deposition of iron, and the anodic decomposition of EDTA. The electrochemical deposition of iron from Fe(II)-EDTA at potentials E < {minus}1.0 V{sub SCE} was confirmed by electrochemical quartz crystal microbalance measurements and energy-dispersive x-ray analysis.

  9. Adsorption and dissociation of Co-EDTA complexes in iron oxide-containing subsurface sands

    SciTech Connect

    Zachara, J.M.; Smith, S.C.; Kuzel, L.S.

    1995-12-31

    The sorption of Co(II)EDTA{sup 2-} (where EDTA is ethylenediaminetetracetic acid) was investigated on goethite and on eight sand-textured Quaternary and Pliocene fluvial sediments. Dual-label tracer techniques were used to follow the distribution of {sup 60}Co(II)- {sup 14}C/EDTA added as the performed 1:1, Co(II) EDTA{sup 2-} complex. Sorption experiments were performed with fixed concentrations of Co(II)EDTA{sup 2-} (10{sup -5} mol/L) and variable pH (all materials), and fixed pH (4.4) with variable Co(II)EDTA{sup 2-} concentrations (two materials), using solids concentrations of 0.5 g/L for goethite and 500 g/L for the sediments and electrolyte concentrations of 0.003 and 0.03 (geothite only) mol/L Ca(ClO{sub 4}){sub 2}. Aqueous Fe{sub aq}{sup 3+} and Al{sub aq}{sup 3+} were measured at the time of the sorption determination. On goethite, Co(II)EDTA{sup 2-} exhibited anion-like sorption, increasing with decreasing pH. Increasing electrolyte concentration decreased sorption, indicating a weak, ion-pair type surface complex. Below pH 6, however, the sorption chemistry of Co{sup 2+} and EDTA{sup 4-} became complex and disparate as a result of Co(II)EDTA{sup 2-} dissociation. Dissociation was driven by exchange with Fe{sub aq}{sup 3+}. A nonelectrostatic surface complexation model that explicitly considered the Fe{sup 3+} -Co(II)EDTA{sup 2-} exchange reaction was able to adequately describe the sorption data using surface complexes with Co(II)EDTA{sup 2-}, FeEDTA{sup -}, and Co{sup 2+}. Iron oxides were a dominant grain-coating phase on over half the sorbents, and X-ray diffraction (XRD), chemical extraction, and microscopic techniques documented the presence of poorly crystalline forms as well as geothite, hematite, and feroxyhite. The coupled adsorption, dissolution, and dissociation process will cause complex distance-variant speciation and retardation behavior for Co(II)EDTA{sup 2-} in subsurface environments. 58 refs., 14 figs., 6 tabs.

  10. Safety assessment of iron EDTA [sodium iron (Fe(3+)) ethylenediaminetetraacetic acid]: summary of toxicological, fortification and exposure data.

    PubMed

    Heimbach, J; Rieth, S; Mohamedshah, F; Slesinski, R; Samuel-Fernando, P; Sheehan, T; Dickmann, R; Borzelleca, J

    2000-01-01

    Iron EDTA [sodium iron (Fe(3+)) ethylenediaminetetraacetic acid (EDTA)], shown to have a significant beneficial effect on iron status by increasing iron bioavailability in human diets, has been proposed for use as a fortificant in certain grain-based products including breakfast cereals and cereal bars. This paper presents an assessment of the safety of iron EDTA for its intended uses in these products. Iron EDTA, like other EDTA-metal complexes, dissociates in the gastrointestinal tract to form iron, which is bioavailable, and an EDTA salt; absorption of the metal ion and EDTA are independent. Because of this dissociation, consideration of information on EDTA compounds other than iron EDTA is relevant to this safety assessment. EDTA compounds are poorly absorbed in the gastrointestinal tract and do not undergo significant metabolic conversion. They have a low degree of acute oral toxicity. EDTA compounds are not reproductive or developmental toxicants when fed with a nutrient-sufficient diet or minimal diets supplemented with zinc. In chronic toxicity studies, diets containing as much as 5% EDTA were without adverse effects. EDTA compounds were not carcinogenic in experimental animal bioassays and are not directly genotoxic. This lack of significant toxicity is consistent with a history of safe use of other EDTA compounds (CaNa(2)EDTA and Na(2)EDTA) approved by the FDA for use as direct food additives. An upper-bound estimated daily intake (EDI) of EDTA from iron EDTA (1.15mg/kg bw/day for the US population) is less than half the acceptable daily intake (ADI) for EDTA of 2. 5mg/kg bw/day established by JECFA. The data collected and published over the past 20 to 30 years demonstrate that iron EDTA is safe and effective for iron fortification of food products and meets the standard of "reasonable certainty of no harm". Based on the published record, iron EDTA may be regarded as generally recognized as safe (GRAS) for the intended food uses and maximum use levels

  11. Kinetics of Fe(III)*EDTA reduction by ascorbic acid

    SciTech Connect

    Li, W.; Harkness, J.B.L.; Mendelsohn, M.H.

    1992-01-01

    The kinetics of the reduction of ferric chelate by ascorbic acid have been determined at a typical flue-gas scrubber-system operating temperature ([approximately]55[degrees]C). The ascorbic acid reaction has the same reduction rate expression as the reduction by bisulfite ions, namely, first order with respect to the concentrations of both Fe(III)*EDTA and monoionic species of ascorbic acid. The reaction rate isnegative first order with respect to Fe(II)*EDTA concentration. In the pH range of 6--8, reduction of the hydrolyzed form of the metal chelate compound was negligible. The rate constant for the ascorbic acid reduction reaction is almost 400 times larger than that for the bisulfite reduction reaction under the same reaction conditions. There was no contribution associated with the nonionized form of ascorbic acid.

  12. Kinetics of Fe(III)*EDTA reduction by ascorbic acid

    SciTech Connect

    Li, W.; Harkness, J.B.L.; Mendelsohn, M.H.

    1992-12-01

    The kinetics of the reduction of ferric chelate by ascorbic acid have been determined at a typical flue-gas scrubber-system operating temperature ({approximately}55{degrees}C). The ascorbic acid reaction has the same reduction rate expression as the reduction by bisulfite ions, namely, first order with respect to the concentrations of both Fe(III)*EDTA and monoionic species of ascorbic acid. The reaction rate isnegative first order with respect to Fe(II)*EDTA concentration. In the pH range of 6--8, reduction of the hydrolyzed form of the metal chelate compound was negligible. The rate constant for the ascorbic acid reduction reaction is almost 400 times larger than that for the bisulfite reduction reaction under the same reaction conditions. There was no contribution associated with the nonionized form of ascorbic acid.

  13. Dissolution of Fe(III)(hydr) oxides by metal-EDTA complexes

    SciTech Connect

    Nowack, B.; Sigg, L. |

    1997-03-01

    The dissolution of Fe(III)(hydr)oxides (goethite and hydrous ferric oxide) by metal-EDTA complexes occurs by ligand-promoted dissolution. The process is initiated by the adsorption of metal-EDTA complexes to the surface and is followed by the dissociation of the complex at the surface and the release of Fe(III)EDTA into solution. The dissolution rate is decreased to a great extent if EDTA is complexed by metals in comparison to the uncomplexed EDTA. The rate decreases in the order EDTA > CaEDTA > PbEDTA > ZnEDTA > CuEDTA > Co(II)EDTA > NiEDTA. Two different rate-limiting steps determine the dissolution process: (1) detachment of Fe(III) from the oxide-structure and (2) dissociation of the metal-EDTA complexes. In the case of goethite, step 1 is slower than step 2 and the dissolution rates by various metals are similar. In the case of hydrous ferric oxide, step 2 is rate-limiting and the effect of the complexed metal is very pronounced. 35 refs., 11 figs., 4 tabs.

  14. Dissolution of iron(III)(HYDR)oxides by metal-EDTA-complexes

    SciTech Connect

    Nowack, B.; Sigg, L.

    1996-10-01

    The dissolution of Fe(III)(hydroxides) (goethite and hydrous ferric oxide) by metal-EDTA complexes occurs by ligand-promoted dissolution. The process is initiated by adsorption of the metal-EDTA to the surface, dissociation of the complex at the surface and release of Fe(III)EDTA into solution. The dissolution rate is decreased to a great extent if EDTA is complexed by metals in comparison to uncomplexed EDTA. The rate decreases in the order EDTA >> CaEDTA > PbEDTA > ZnEDTA > CuEDTA > Co(II)EDTA > NiEDTA. Two different rate-limiting steps determine the system: (1) detachment of Fe(III) from the oxide-structure and (2) dissociation of the metal-EDTA complexes. In the case of goethite, step (1) is more important than (2) and the difference in the dissolution rate for several metals is small. In the case of hydrous ferric oxide, step (2) is rate-limiting and the effect of the complexed metal is very pronounced.

  15. Degradation of metal-EDTA complexes by resting cells of the bacterial strain DSM 9103

    SciTech Connect

    Satroutdinov, A.D.; Dedyukhina, E.G.; Chistyakova, T.I.; Witschel, M.; Minkevich, I.G.; Eroshin, V.K.; Egli, T.

    2000-05-01

    Ethylenediaminetetraacetate (EDTA), an industrially important chelating agent, forms very stable complexes with di- and trivalent metal ions, and in both wastewater and natural waters it is normally present in the metal-associated form. Therefore, the influence of EDTA speciation on its utilization by the EDTA-degrading bacterial strain DSM 9103 was investigated. EDTA-grown cells harvested from the exponential phase of a batch culture were incubated with 1 mM of various EDTA species and the EDTA concentration in the assay was monitored as a function of time. Uncomplexed EDTA as well as complexes with low stability constants were found to be readily degraded to completion at a constant rate. For more stable EDTA chelates (i.e., chelates of Co{sup 2+}, Cu{sup 2+}, Zn{sup 2+}, and Pb{sup 2+}) the data suggest that these complexes were not used directly by the cells but that they had to dissociate prior to degradation. The rate of this dissociation step possibly determined the microbial degradation of these complexes. CdEDTA{sup 2{minus}} and Fe(III)EDTA{sup {minus}} were not degraded within 48 h. In case of CdEDTA{sup 2{minus}} the toxicity of freed Cd{sup 2+} ions most likely prevented a significant degradation of the complex, whereas in case of Fe(III)EDTA{sup {minus}} a combination of metal or complex toxicity and the very slow dissociation of the complex might explain the absence of degradation.

  16. Simulation of the mobility of metal - EDTA complexes in groundwater: The influence of contaminant metals

    USGS Publications Warehouse

    Friedly, J.C.; Kent, D.B.; Davis, J.A.

    2002-01-01

    Reactive transport simulations were conducted to model chemical reactions between metal - EDTA (ethylenediaminetetraacetic acid) complexes during transport in a mildly acidic quartz - sand aquifer. Simulations were compared with the results of small-scale tracer tests wherein nickel-, zinc-, and calcium - EDTA complexes and free EDTA were injected into three distinct chemical zones of a plume of sewage-contaminated groundwater. One zone had a large mass of adsorbed, sewage-derived zinc; one zone had a large mass of adsorbed manganese resulting from mildly reducing conditions created bythe sewage plume; and one zone had significantly less adsorbed manganese and negligible zinc background. The chemical model assumed that the dissolution of iron(III) from metal - hydroxypolymer coatings on the aquifer sediments by the metal - EDTA complexes was kinetically restricted. All other reactions, including metal - EDTA complexation, zinc and manganese adsorption, and aluminum hydroxide dissolution were assumed to reach equilibrium on the time scale of transport; equilibrium constants were either taken from the literature or determined independently in the laboratory. A single iron(III) dissolution rate constant was used to fit the breakthrough curves observed in the zone with negligible zinc background. Simulation results agreed well with the experimental data in all three zones, which included temporal moments derived from breakthrough curves at different distances downgradient from the injections and spatial moments calculated from synoptic samplings conducted at different times. Results show that the tracer cloud was near equilibrium with respect to Fe in the sediment after 11 m of transport in the Zn-contaminated region but remained far from equilibrium in the other two zones. Sensitivity studies showed that the relative rate of iron(III) dissolution by the different metal - EDTA complexes was less important than the fact that these reactions are rate controlled. Results

  17. Nucleation of calcium carbonate in presence of citric acid, DTPA, EDTA and pyromellitic acid.

    PubMed

    Westin, K-J; Rasmuson, A C

    2005-02-15

    The influence of four calcium complexing additives, i.e., citric acid (CIT), diethylenetriaminepentaacetic acid (DTPA), ethylenediaminetetraacetic acid (EDTA) and pyromellitic acid (PMA), and their concentration on the induction time of calcium carbonate nucleation has been studied. The experiments were performed by rapidly mixing a sodium carbonate solution and a calcium chloride solution of various concentrations. The induction time was obtained by recording the white light absorption of the solution. Chemical speciation was used to estimate the initial thermodynamic driving force of each experiment. The induction time was found to increase with additive concentration. The effect varies from one additive to another. CIT causes the greatest increase in induction time and PMA the least. Using classical nucleation theory the experimental data were evaluated in terms of the interfacial energy. In pure water a value of 37.8 mJ m(-2) was obtained, showing good agreement with other works. CIT, DTPA and EDTA caused a notable increase of the interfacial energy at a concentration of 0.5 mmol l(-1). PMA does not appear to have any effect at all on the interfacial energy. Different mechanisms for the influence of the additives on the measured induction time and on the estimated interfacial energy are discussed. PMID:15589542

  18. Degradation of EDTA and novel complexing agents in pulp and paper mill process and waste waters by Fenton's reagent.

    PubMed

    Pirkanniemi, Kari; Metsärinne, Sirpa; Sillanpää, Mika

    2007-08-17

    Fenton's process was used in oxidative degradation of ethylediaminetetraacetic acid (EDTA) and novel complexing agents, namely BCA5 and BCA6, in distilled water and spiked samples of integrated pulp and paper mill waste water and ECF-pulp bleaching effluent. In waste water, over 90% of EDTA was degraded within 3 min when temperature was 60 degrees C, pH 4, and molecular ratio of H2O2:Fe2+:EDTA was 70:2:1 (0.26 mM EDTA) or higher. In spiked ECF bleaching effluent up to 42% of EDTA was degraded in similar reaction conditions, still higher than published results indicate biological waste water treatment of pulp and paper mill waste water being capable of. In pH 3, EDTA proved readily degradable by Fenton's process in otherwise similar conditions. According to these results, Fenton's process could be used as a pre-treatment method for EDTA-containing bleaching effluents prior to the biological waste water treatment. In addition, BCA5 and BCA6 proved their superiority in terms of degradability also by Fenton's process in both pH 3 and 4.

  19. Effect of the formation of EDTA complexes on the diffusion of metal ions in water

    NASA Astrophysics Data System (ADS)

    Furukawa, Kenji; Takahashi, Yoshio; Sato, Haruo

    2007-09-01

    The diffusion coefficients of aquo metal ions (M z+ ) and their EDTA complexes (M-EDTA ( z-4)+ ) were compared to understand the effect of EDTA complexation on the diffusion of metal ions by the diffusion cell method for Co 2+, Ga 3+, Rb +, Sr 2+, Ag +, Cd 2+, Cs +, Th 4+, UO22+, and trivalent lanthanides. Most studies about ionic diffusion in water have dealt with free ion (hydrated ion). In many cases, however, polyvalent ions are dissolved as complexed species in natural waters. Hence, we need to study the diffusion behavior of complexes in order to understand the diffusion phenomenon in natural aquifer and to measure speciation by diffusive gradient in thin films (DGT), which requires the diffusion coefficients of the species examined. For many ions, the diffusion coefficients of M-EDTA ( z-4)+ are smaller than those of hydrated ions, but the diffusion coefficients of M-EDTA ( z-4)+ are larger than those of hydrated ions for ions with high ionic potentials (Ga 3+ and Th 4+). As a result, the diffusion coefficients of EDTA complexes are similar among various metal ions. In other words, the diffusion of each ion loses its characteristics by the complexation with EDTA. Although the difference is subtle, it was also found that the diffusion coefficients of EDTA complexes increase as the ionic potential increases, which can be explained by the size of the EDTA complex of each metal ion.

  20. Dynamic NMR of Intramolecular Exchange Processes in EDTA Complexes of Sc[superscript 3+], Y[superscript 3+], and La[superscript 3+

    ERIC Educational Resources Information Center

    Ba, Yong; Han, Steven; Ni, Lily; Su, Tony; Garcia, Andres

    2006-01-01

    Dynamic NMR makes use of the effect of chemical exchanges on NMR spectra to study kinetics and thermodynamics. An advanced physical chemistry lab experiment was developed to study the intramolecular exchange processes of EDTA (the disodium salt of ethylenediaminetetraacetic acid) metal complexes. EDTA is an important chelating agent, used in…

  1. Ferrous iron oxidation by molecular oxygen under acidic conditions: The effect of citrate, EDTA and fulvic acid

    NASA Astrophysics Data System (ADS)

    Jones, Adele M.; Griffin, Philippa J.; Waite, T. David

    2015-07-01

    In this study, the rates of Fe(II) oxidation by molecular oxygen in the presence of citrate, ethylenediaminetetraacetic acid (EDTA) and Suwannee River fulvic acid (SRFA) were determined over the pH range 4.0-5.5 and, for all of the ligands investigated, found to be substantially faster than oxidation rates in the absence of any ligand. EDTA was found to be particularly effective in enhancing the rate of Fe(II) oxidation when sufficient EDTA was available to complex all Fe(II) present in solution, with a kinetic model of the process found to adequately describe all results obtained. When Fe(II) was only partially complexed by EDTA, reactions with reactive oxygen species (ROS) and heterogeneous Fe(II) oxidation were found to contribute significantly to the removal rate of iron from solution at different stages of oxidation. This was possible due to the rapid rate at which EDTA enhanced Fe(II) oxidation and formed ROS and Fe(III). The rapid rate of Fe(III) generation facilitated the formation of free ferric ion activities in excess of those required for ferric oxyhydroxide precipitation following Fe(III)-EDTA dissociation. In comparison, the rate of Fe(II) oxidation was slower in the presence of citrate, and therefore the concentrations of free Fe(III) able to form in the initial stages of Fe(II) oxidation were much lower than those formed in the presence of EDTA, despite the resultant Fe(III)-citrate complex being less stable than that of Fe(III)-EDTA. The slower rate of citrate enhanced oxidation also resulted in slower rates of ROS generation, and, as such, oxidation of the remaining inorganic Fe(II) species by ROS was negligible. Overall, this study demonstrates that organic ligands may substantially enhance the rate of Fe(II) oxidation. Even under circumstances where the ligand is not present at sufficient concentrations to complex all of the Fe(II) in solution, ensuing oxidative processes may sustain an enhanced rate of Fe(II) oxidation relative to that of

  2. An Aqueous Thermodynamic Model for the Complexation of Nickel with EDTA Valid to high Base Concentration

    SciTech Connect

    Felmy, Andrew R.; Qafoku, Odeta

    2004-09-01

    An aqueous thermodynamic model is developed which accurately describes the effects of high base concentration on the complexation of Ni2+ by ethylenedinitrilotetraacetic acid (EDTA). The model is primarily developed from an extensive data on the solubility of Ni(OH)2(c) in the presence of EDTA and in the presence and absence of Ca2+ as the competing metal ion. The solubility data for Ni(OH)2(c) were obtained in solutions ranging in NaOH concentration from 0.01 to 11.6m, and in Ca 2+ concentrations extending to saturation with respect to portlandite, Ca(OH)2. Owing to the inert nature of the Ni-EDTA complexation reactions, solubility experiments were approached from both the oversaturation and undersaturation direction and over time frames extending to 413 days. The final aqueous thermodynamic model is based upon the equations of Pitzer, accurately predicts the observed solubilities to concentrations as high as 11.6m NaOH, and is consistent with UV-Vis spectroscopic studies of the complexes in solution.

  3. Deposition of Metal Oxide Films from Metal-EDTA Complexes by Flame Spray Technique

    NASA Astrophysics Data System (ADS)

    Komatsu, Keiji; Sekiya, Tetsuo; Toyama, Ayumu; Hasebe, Yasuhiro; Nakamura, Atsushi; Noguchi, Masahiro; Li, Yu; Ohshio, Shigeo; Akasaka, Hiroki; Muramatsu, Hiroyuki; Saitoh, Hidetoshi

    2014-06-01

    R2O3 (R = Y, Eu, Er) metal oxides were synthesized from metal-ethylenediaminetetraacetic acid (EDTA) complexes using a flame spray technique. As this technique enables high deposition rates, films with thickness of several tens of micrometers were obtained. Films of yttria, europia, and erbia phase were synthesized on stainless-steel substrates with reaction assistance by H2-O2 combustion gas. The oxide films consisted of the desired crystalline phase with micropores. The porosity of the films was in the range of 6-15%, varying with the metal used. These results suggest that the true density of the metal oxide obtained from metal-EDTA powder through the thermal reaction process plays an important role in achieving film with the desired porosity.

  4. Intensification of luminescence of Europium-EDTA complex in polyvinyl pyrrolidone films by copper nanoparticles

    NASA Astrophysics Data System (ADS)

    Reisfeld, Renata; Levchenko, Viktoria; Lazarowska, Agata; Mahlik, Sebastian; Grinberg, Marek

    2016-09-01

    Stable copper nanoparticles (CuNPs) were prepared and incorporated into polyvinylpyrrolidone (PVP) films together with pre-prepared complex of europium-ethylenediaminetetraacetic acid (EuEDTA). From the comparison of the excitation spectrum of the complex alone and of the complex in conjunction with CuNPs an increased fluorescence intensity of the complex is observed as the result of interaction of the complex with surface plasmons of copper. This effect is maximal when the extinction band of CuNPs coincides with the absorption maximum of the complex, as much more light reaches the excited state of europium in the complex during the excitation events as the result of light scattered by copper plasmons. An additional band was observed in the excitation spectrum of the complex in co-doped by the CuNPs around 320÷390 nm which we attribute to electron transfer from CuNPs to excited state of europium.

  5. Luminescent and magnetic materials with a high content of Eu(3+)-EDTA complexes.

    PubMed

    Pires, G P; Costa, I F; Brito, H F; Faustino, W M; Teotonio, E E S

    2016-07-01

    Bifunctional optical magnetic materials with a high europium content have been prepared. Chelating groups were introduced on the Fe3O4 surface with organosilanes containing ethylenediaminetetraacetic acid (EDTA) derivatives, which were previously prepared via a reaction between EDTA-dianhydride and aminoalkoxysilane agents: 3-(trimethoxysilyl)propylamine (1N), N-[3(trimethoxysilyl)propyl]ethylenediamine (2N) and N(1)-(3-trimethoxysilylpropyl)diethylenetriamine) (3N). The first coordination sphere of Ln-EDTA complexes present on the modified surfaces of Fe3O4 particles was completed by addition of β-diketonate ligands (tta: thenoyltrifluoroacetone, dbm: dibenzoylmethane, bzac: benzoylacetone and acac: acetylacetone) in order to improve their luminescence properties. The materials were characterized by powder X-ray diffraction (XRD), vibrating sample magnetometry (VSM), scanning electron microscopy (SEM), transmission electron microscopy (TEM), thermogravimetric analysis (TGA), and wavelength dispersive X-ray fluorescence (WDXRF) and Fourier-transform infrared (FT-IR) spectroscopy as well as by zeta potential measurements and luminescence spectroscopy. The hybrid materials exhibited intense red emission, which can be assigned to the 4f-4f transitions of the Eu(3+) ion, indicating an efficient intramolecular ligand-to-metal energy transfer. The experimental intensity parameters (Ω2 and Ω4), lifetimes (τ), as well as radiative (Arad) and non-radiative (Anrad) decay rates of the Eu(3+) ion were determined and discussed. The strategies used to obtain these materials may contribute to the development of several bifunctional systems for practical applications. PMID:27301580

  6. Influence of solution structure on adsorption of metal-EDTA complexes onto iron oxides

    SciTech Connect

    Nowack, B.; Sigg, L.

    1995-12-01

    The adsorption characteristics of a variety of divalent and trivalent metal-EDTA complexes onto goethite ({alpha}-FeOOH) and amorphous Fe(OH){sub 3} were examined. Uncomplexed EDTA is adsorbed as a ligand-like binuclear complex at low pH and as a mononuclear complex at high pH. The complexes of the divalent metals Ca, Zn, Ni, Cu, Co(II), and Ph show all the same ligand-like adsorption behavior. They are characterized by a quinquedentate structure in solution. Their adsorption in function of pH can be described by a ternary surface complex. The bidentate Pd(II) EDTA is adsorbed much stronger, but also ligand-like. La(III) EDTA and Bi(III) EDTA are adsorbed very strongly over the whole pH-range. The sexidentate complex of Co(III) is at low pH weakly adsorbed outer-spherically. Fe(III) EDTA is weakly adsorbed over the whole pH-range. The mobility of EDTA complexes in an aquifer depends therefore on the pH and on the type of complex.

  7. Titanium dioxide mediated photocatalysis of Pb(II)- and Co(II)-EDTA complexes

    SciTech Connect

    Davis, A.P.; Vohra, M.S.; Ayres, D.M.

    1995-12-31

    The photocatalysis of lead and cobalt(II) complexed to EDTA was evaluated under a variety of experimental conditions. Adsorption characteristics of the metals and the metal complexes were also determined. A recirculating batch system was used to quantify photocatalytic oxidation rates. EDTA mineralization and total dissolved metal were monitored. Separations of Co(II*), Co(II)-EDTA, and Co(III)-EDTA were made with a method using Dowex cation exchange resin. Adsorptions of Pb(II), Co(II), EDTA, and the corresponding metal complexes was examined using concentrations of 10{sup -}{sup 5} to 10{sup -}{sup 3} M in 2 g/L TiO{sub 2}. After purging and pH adjustment, the samples were shaken overnight. The final pH and metal and TOC concentrations were determined. Results showed that the photocatablytic oxidation of metal-EDTA complexes is independent of pH from 5 to 7. This contrasts with the adsorption of these species onto TiO{sub 2}, which decreases at neutral-high pH, suggesting that adsorption is not a prerequisite to photocalysis. For Co(II)-EDTA, a competing pH dependent conversion to Co(III)-EDTA is noted.

  8. Effect of adsorbed metals ions on the transport of Zn- and Ni-EDTA complexes in a sand and gravel aquifer

    USGS Publications Warehouse

    Kent, D.B.; Davis, J.A.; Anderson, L.C.D.; Rea, B.A.; Coston, J.A.

    2002-01-01

    Adsorption, complexation, and dissolution reactions strongly influenced the transport of metal ions complexed with ethylenediaminetetraacetic acid (EDTA) in a predominantly quartz-sand aquifer during two tracer tests conducted under mildly reducing conditions at pH 5.8 to 6.1. In tracer test M89, EDTA complexes of zinc (Zn) and nickel (Ni), along with excess free EDTA, were injected such that the lower portion of the tracer cloud traveled through a region with adsorbed manganese (Mn) and the upper portion of the tracer cloud traveled through a region with adsorbed Zn. In tracer test S89, Ni- and Zn-EDTA complexes, along with excess EDTA complexed with calcium (Ca), were injected into a region with adsorbed Mn. The only discernable chemical reaction between Ni-EDTA and the sediments was a small degree of reversible adsorption leading to minor retardation. In the absence of adsorbed Zn, the injected Zn was displaced from EDTA complexes by iron(III) [Fe(III)] dissolved from the sediments. Displacement of Zn by Fe(III) on EDTA became increasingly thermodynamically favorable with decreasing total EDTA concentration. The reaction was slow compared to the time-scale of transport. Free EDTA rapidly dissolved aluminum (Al) from the sediments, which was subsequently displaced slowly by Fe. In the portion of tracer cloud M89 that traveled through the region contaminated with adsorbed Zn, little displacement of Zn complexed with EDTA was observed, and Al was rapidly displaced from EDTA by Zn desorbed from the sediments, in agreement with equilibrium calculations. In tracer test S89, desorption of Mn dominated over the more thermodynamically favorable dissolution of Al oxyhydroxides. Comparison with results from M89 suggests that dissolution of Al oxyhydroxides in coatings on these sediment grains by Ca-EDTA was rate-limited whereas that by free EDTA reached equilibrium on the time-scale of transport. Rates of desorption are much faster than rates of dissolution of Fe

  9. Influence of ethylenediaminetetraacetic acid (EDTA) on the structural stability of endoglucanase from Aspergillus aculeatus.

    PubMed

    Naika, Gajendra S; Tiku, Purnima Kaul

    2011-07-13

    The effect of the chelating agent ethylenediaminetetraacetic acid (EDTA) on the structure and function of endoglucanase is studied. In the presence of 2 mM EDTA, endoglucanase showed an enhanced enzymatic activity of 1.5-fold compared to control. No further change in activity was observed with increase in the concentration of EDTA to 5 mM. The K(m) values for control and in the presence of EDTA are 0.060 and 0.044%, respectively, and K(cat) was 1.9 min(-1) in the presence of EDTA. The kinetic parameters indicated a decrease in the K(m) with an increase in the K(cat). Far-ultraviolet circular dichroism (far-UV-CD) results showed a 20% decrease in ellipticity values at 217 nm in the presence of EDTA compared to native enzyme. The apparent T(m) shifted from a control value of 57 ± 1 to 76 ± 1 °C in the presence of EDTA (5 mM). The above results suggested that the enhanced activity in the presence of EDTA is due to an increase in the K(cat) and flexible conformation of the enzyme. The stability of endoglucanase increased in the presence of EDTA.

  10. Evaluating EDTA as a substitute for phosphoric acid-etching of enamel and dentin.

    PubMed

    Imbery, Terence A; Kennedy, Matthew; Janus, Charles; Moon, Peter C

    2012-01-01

    Matrix metalloproteinases (MMPs) are proteolytic enzymes released when dentin is acid-etched. The enzymes are capable of destroying unprotected collagen fibrils that are not encapsulated by the dentin adhesive. Chlorhexidine applied after etching inhibits the activation of released MMPs, whereas neutral ethylenediamine tetra-acetic acid (EDTA) prevents the release of MMPs. The purpose of this study was to determine if conditioning enamel and dentin with EDTA can be a substitute for treating acid-etching enamel and dentin with chlorhexidine. A column of composite resin was bonded to enamel and dentin after conditioning. Shear bond strengths were evaluated after 48 hours and after accelerated aging for three hours in 12% sodium hypochlorite. Shear bond strengths ranged from 15.6 MP a for accelerated aged EDTA enamel specimens to 26.8 MPa for dentin conditioned with EDTA and tested after 48 hours. A three-way ANOVA and a Tukey HSD test found statistically significant differences among the eight groups and the three independent variables (P < 0.05). EDTA was successfully substituted for phosphoric acid-etched enamel and dentin treated with chlorhexidine. Interactions of conditioning agent and aging were significant for dentin but not for enamel. In an effort to reduce the detrimental effects of MMPs, conditioning enamel and dentin with EDTA is an alternative to treating acid-etched dentin and enamel with chlorhexidine.

  11. Two supramolecular complexes based on polyoxometalates and Co-EDTA units via covalent connection or non-covalent interaction

    NASA Astrophysics Data System (ADS)

    Teng, Chunlin; Xiao, Hanxi; Cai, Qing; Tang, Jianting; Cai, Tiejun; Deng, Qian

    2016-11-01

    Two new 3D network organic-inorganic hybrid supramolecular complexes {[Na6(CoEDTA)2(H2O)13]·(H2SiW12O40)·xH2O}n (1) and [CoH4EDTA(H2O)]2(SiW12O40)·15H2O (2) (H4EDTA=Ethylenediamine tetraacetic acid) have been successfully synthesized by solution method, and characterized by infrared spectrum (IR), thermogravimetric-differential thermal analysis (TG-DTA), cyclic voltammetry (CV) and single-crystal X-ray diffraction (XRD). Both of the complexes are the supramolecules, but with different liking mode, they are two representative models of supramolecule. complex (1) is a 3D infinite network supramolecular coordination polymer with a rare multi-metal sturcture of sodium-cobalt-containing, which is mainly linked through coordinate-covalent bonds. While complex (2) is normal supramolecule, which linked by non-covalent interactions, such as H-bonding interaction, electrostatic interaction and van der waals force. Both of complex (1) and (2) exhibit good catalytic activities for catalytic oxidation of methanol, when the initial concentration of methanol is 3.0 g m-3, flow rate is 10 mL min-1, and the quality of catalyst is 0.2 g, for complex (1) and complex (2) the maximum elimination rates of methanol are 85% (150 °C) and 92% (120 °C), respectively.

  12. Enhancement of electrokinetic decontamination with EDTA.

    PubMed

    Karim, M A; Khan, L I

    2012-01-01

    The effect of ethylenediaminetetraacetic acid (EDTA) during electrokinetic decontamination (EKD) was investigated in this research. EDTA is a ligand that can form soluble complexes with precipitated heavy metals inside soil pores. Millpond sludge, primarily contaminated with lead (Pb) and zinc (Zn), was subjected to EKD with and without the presence of EDTA. Dilute EDTA solutions with strengths of 0.05 M and 0.125 M were injected into the millpond sludge by electroosmosis. Several beneficial effects of using EDTA were observed in this research. One was that the presence of EDTA substantially increased the electroosmotic (EO) flow in the millpond sludge indicating that it could significantly reduce the duration of EKD. Another advantage was that a significantly higher percentage of Pb and Zn removal was achieved from the solid phase due to the complexation of EDTA with these heavy metals. Also, EDTA was able to prevent the precipitation of metals at the cathode electrode, typically observed in EKD process. PMID:23393970

  13. Evaluation of the tratment of metal-EDTA complexes using Ti0{sub 2} photocatalysis

    SciTech Connect

    Madden, T.; Datyte, A.K.; Prairie, M.R.; Stange, B.M.

    1996-03-01

    This study has demonstrated the feasibility of TiO{sub 2} photocatalysis to treat EDTA and several metal-EDTA complexes that can be found in industrial wastewaters. For the EDTA complexes of metals capable of photodeposition, such as Cu and Pb, certain reaction conditions were shown to facilitate the simultaneous complex degradation and photodeposition of these metals onto the catalyst. With metals that do not easily photodeposit, such as Ni and Cd, it is shown that the complex degradation is still facilitated, and can enhance other metals removal processes after photocatalytic treatment. Because the treatment of these metal-EDTA complexes typically requires special measures, there may exist situations where TiO{sub 2} photocatalysis could actually be the preferred method of treatment. However, its use should be compared economically to other more established advanced oxidation technologies. This necessity is demonstrated in the economic comparison to ozone treatment for EDTA degradation alone, where ozone treatment appears to be the clear choice in this application.

  14. Simulation of the influence of EDTA on the sorption of heavy metals by humic acids

    NASA Astrophysics Data System (ADS)

    Kropacheva, T. N.; Didik, M. V.; Kornev, V. I.

    2015-04-01

    The results of mathematical simulation of sorption equilibria with the participation of divalent cations of heavy metals (HMs), chelant (EDTA), and insoluble forms of humic acids (HAs) are discussed. It is shown that the formation of chelates of metals with EDTA in solutions results in the decreasing sorption of the metals by humic acids. We also analyzed the effect of the acidity of the medium and the HM: EDTA: HA ratio (in a wide range) on the desorption of metals. The desorbing effect of EDTA on the metals is the highest at pH 3-5 and increases with an increase in the concentration of EDTA and a decrease in the concentration of HAs. With respect to the remobilization of metals under the impact of EDTA, the metal cations can be arranged into the following sequence: Cu(II) > Ni(II) > Pb(II) ≫ Cd(II) > Co(II) > Zn(II). The obtained data have been used to analyze the remobilization / extraction of HMs from soils with a high content of humic substances.

  15. EDTA and citric acid mediated phytoextraction of Zn, Cu, Pb and Cd through marigold (Tagetes erecta).

    PubMed

    Sinhal, V K; Srivastava, Alok; Singh, V P

    2010-05-01

    Phytoextraction is an emerging cost-effective solution for remediation of contaminated soils which involves the removal of toxins, especially heavy metals and metalloids, by the roots of the plants with subsequent transport to aerial plant organs. The aim of the present investigation is to study the effects of EDTA and citric acid on accumulation potential of marigold (Tagetes erecta) to Zn, Cu, Pb, and Cd and also to evaluate the impacts of these chelators (EDTA and citric acid) in combination with all the four heavy metals on the growth of marigold. The plants were grown in pots and treated with Zn (7.3 mg l(-1)), Cu (7.5 mg I(-1)), Pb (3.7 mg l(-1)) and Cd (0.2 mg l(-1)) alone and in combination with different doses of EDTA i.e., 10, 20 and 30 mg l(-1). All the three doses of EDTA i.e., 10, 20 and 30 mg l(-1) significantly increased the accumulation of Zn, Cu, Pb and Cd by roots, stems and leaves as compared to control treatments. The 30 mg l(-1) concentration of citric acid showed reduced accumulation of these metals by root, stem and leaves as compared to lower doses i.e., 10 and 20 mg l(-1). Among the four heavy metals, Zn accumulated in the great amount (526.34 mg kg(-1) DW) followed by Cu (443.14 mg kg(-1) DW), Pb (393.16 mg kg(-1) DW) and Cd (333.62 mg kg(-1) DW) in leaves with 30 mg l(-1) EDTA treatment. The highest concentration of EDTA and citric acid (30 mg l(-1)) caused significant reduction in growth of marigold in terms of plant height, fresh weight of plant, total chlorophyll, carbohydrate content and protein content. Thus EDTA and citric acid efficiently increased the phytoextractability of marigold which can be used to remediate the soil contaminated with these metals.

  16. Photo-catalytic Degradation and Sorption of Radio-cobalt from EDTA-Co Complexes Using Manganese Oxide Materials - 12220

    SciTech Connect

    Koivula, Risto; Harjula, Risto; Tusa, Esko

    2012-07-01

    The synthesised cryptomelane-type α-MnO{sub 2} was tested for its Co-57 uptake properties in UV-photo-reactor filled with 10 μM Co-EDTA solution with a background of 10 mM NaNO{sub 3}. High cobalt uptake of 96% was observed after 1 hour of UV irradiation. As for comparison, a well-known TiO{sub 2} (Degussa P25) was tested as reference material that showed about 92% cobalt uptake after six hours of irradiation in identical experiment conditions. It was also noted that the cobalt uptake on cryptomelane with out UV irradiation was modest, only about 10%. Decreasing the pH of the Co-EDTA solution had severe effects on the cobalt uptake mainly due to the rather high point of zero charge of the MnO{sub 2} surface (pzc at pH ∼4.5). Modifying the synthesis procedure we were able to produce a material that functioned well even in solution of pH 3 giving cobalt uptake of almost 99%. The known properties, catalytic and ion exchange, of manganese oxides were simultaneously used for the separation of EDTA complexed Co-57. Tunnel structured cryptomelane -type showed very fast and efficient Co uptake properties outperforming the well known and widely used Degussa P25 TiO{sub 2} in both counts. The layered structured manganese oxide, birnessite, reached also as high Co removal level as the reference material Degussa did but the reaction rate was considerably faster. Since the decontamination solutions are typically slightly acidic and the point of zero charge of the manganese oxides are rather high > pH 4.5 the material had to be modified. This modified material had tolerance to acidic solutions and it's Co uptake performance remained high in the solutions of lower pH (pH 3). Increasing the ion concentration of test solutions, background concentration, didn't affect the final Co uptake level; however, some changes in the uptake kinetics could be seen. The increase in EDTA/MoMO ratio was clearly reflected in the Co uptake curves. The obtained results of manganese oxide were

  17. Controlling of dielectrical properties of hydroxyapatite by ethylenediamine tetraacetic acid (EDTA) for bone healing applications.

    PubMed

    Kaygili, Omer; Ates, Tankut; Keser, Serhat; Al-Ghamdi, Ahmed A; Yakuphanoglu, Fahrettin

    2014-08-14

    The hydroxyapatite (HAp) samples in the presence of various amounts of ethylenediamine tetraacetic acid (EDTA) were prepared by sol-gel method. The effects of EDTA on the crystallinity, phase structure, chemical, micro-structural and dielectric properties of HAp samples were investigated. With the addition of EDTA, the average crystallite size of the HAp samples is gradually decreased from 30 to 22 nm and the crystallinity is in the range of 65-71%. The values of the lattice parameters (a and c) and volume of the unit cell are decreased by stages with the addition of EDTA. The dielectric parameters such as relative permittivity, dielectric loss and relaxation time are affected by the adding of EDTA. The alternating current conductivity of the as-synthesized hydroxyapatites increases with the increasing frequency and obeys the universal power law behavior. The HAp samples exhibit a non-Debye relaxation mechanism. The obtained results that the dielectrical parameters of the HAp sample can be controlled by EDTA. PMID:24747847

  18. Controlling of dielectrical properties of hydroxyapatite by ethylenediamine tetraacetic acid (EDTA) for bone healing applications.

    PubMed

    Kaygili, Omer; Ates, Tankut; Keser, Serhat; Al-Ghamdi, Ahmed A; Yakuphanoglu, Fahrettin

    2014-08-14

    The hydroxyapatite (HAp) samples in the presence of various amounts of ethylenediamine tetraacetic acid (EDTA) were prepared by sol-gel method. The effects of EDTA on the crystallinity, phase structure, chemical, micro-structural and dielectric properties of HAp samples were investigated. With the addition of EDTA, the average crystallite size of the HAp samples is gradually decreased from 30 to 22 nm and the crystallinity is in the range of 65-71%. The values of the lattice parameters (a and c) and volume of the unit cell are decreased by stages with the addition of EDTA. The dielectric parameters such as relative permittivity, dielectric loss and relaxation time are affected by the adding of EDTA. The alternating current conductivity of the as-synthesized hydroxyapatites increases with the increasing frequency and obeys the universal power law behavior. The HAp samples exhibit a non-Debye relaxation mechanism. The obtained results that the dielectrical parameters of the HAp sample can be controlled by EDTA.

  19. Determination of conditional stability constants for some divalent transition metal ion-EDTA complexes by electrospray ionization mass spectrometry.

    PubMed

    Boija, Susanne; Almesåker, Ann; Hedenström, Erik; Bylund, Dan; Edlund, Håkan; Norgren, Magnus

    2014-07-01

    Conditional stability constants of coordination complexes comprising divalent transition metals, Cu(2+), Ni(2+), Zn(2+), Co(2+), and ethylenediaminetetraacetic acid (EDTA) were determined utilizing electrospray ionization mass spectrometry. The deviation of signal response of a reference complex was monitored at addition of a second metal ion. The conditional stability constant for the competing metal was then determined through solution equilibria equations. The method showed to be applicable to a system where Co(2+) and Zn(2+) competed for EDTA at pH 5. When Cu(2+) and Ni(2+) competed for EDTA, the equilibrium changed over time. This change was shown to be affected in rate and size by the type of organic solvent added. In this work, 30% of either methanol or acetonitrile was used. It was found that if calibration curves are prepared for both metal complexes in solution and the measurements are repeated with sufficient time space, any change in equilibrium of sample solutions will be discovered. PMID:25044839

  20. Solution structures of europium(III) complexes of ethylenediaminetetraacetic acid

    SciTech Connect

    Latva, M.; Kankara, J.; Haapakka, K.

    1996-04-01

    Coordination of ethylenediaminetetraacetic acid (EDTA) with europium(III) has been studied at different concentrations in solution using {sup 7}F{sub 0}{yields}{sup 5}D{sub 0} excitation spectroscopy and excited-state lifetime measurements. EDTA forms with Eu(III) ion three different species in equimolar solutions at room temperature. At low pH values EuEDTAH is formed and at higher pH values than 1.5 two EuEDTA{sup -} complexes, which differ from each other with one water molecule in the first coordination sphere of the Eu(III) ion, total coordination number and coordination geometry, are also formed. When the concentration of EDTA is higher than the concentration of Eu(III), an EuEDTA(EDTAH){sup 4-} species where the second EDTA is weakly coordinated to EuEDTA{sup -}, is formed. If the concentration of Eu(III) ion is higher than EDTA, the extra Eu(III) ions associate with EuEDTA{sup -} and link to one of the carboxylate groups of EDTA thus causing a shortening of the excited-state lifetime of the EuEDTA{sup -} complex.

  1. [Evaluation of compounding EDTA and citric acid on remediation of heavy metals contaminated soil].

    PubMed

    Yin, Xue; Chen, Jia-Jun; Cai, Wen-Min

    2014-08-01

    As commonly used eluents, Na2EDTA (EDTA) and citric acid (CA) have been widely applied in remediation of soil contaminated by heavy metals. In order to evaluate the removal of arsenic, cadmium, copper, and lead in the contaminated soil collected in a chemical plant by compounding EDTA and CA, a series of stirring experiments were conducted. Furthermore, the changes in speciation distribution of heavy metals before and after washing were studied. The results showed that, adopting the optimal molar ratio of EDTA/CA (1:1), when the pH of the solution was 3, the stirring time was 30 min, the stirring rate was 150 r x min(-1) and the L/S was 5:1, the removal rates of arsenic, cadmium, copper and lead could reach 11.72%, 43.39%, 24.36% and 27.17%, respectively. And it was found that after washing, for arsenic and copper, the content of acid dissolved fraction rose which increased the percentage of available contents. Fe-Mn oxide fraction mainly contributed to the removal of copper. As for cadmium, the percentages of acid dissolved fraction, Fe-Mn oxide fraction and organic fraction also decreased. In practical projects, speciation changes would pose certain environmental risk after soil washing, which should be taken into consideration.

  2. Competitive removal of Cu-EDTA and Ni-EDTA via microwave-enhanced Fenton oxidation with hydroxide precipitation.

    PubMed

    Lin, Qintie; Pan, Hanping; Yao, Kun; Pan, Yonggang; Long, Wei

    2015-01-01

    Ethylenediaminetetraacetic acid (EDTA) can form very stable complexes with heavy metal ions, greatly inhibiting conventional metal-removal technologies used in water treatment. Both the oxidation of EDTA and the reduction of metal ions in metal-EDTA systems via the microwave-enhanced Fenton reaction followed by hydroxide precipitation were investigated. The Cu(II)-Ni(II)-EDTA, Cu(II)-EDTA and Ni(II)-EDTA exhibited widely different decomplexation efficiencies under equivalent conditions. When the reaction reached equilibrium, the chemical oxygen demand was reduced by a microwave-enhanced Fenton reaction in different systems and the reduction order from high to low was Cu(II)-Ni(II)-EDTA ≈ Cu(II)-EDTA > Ni(II)-EDTA. The removal efficiencies of both Cu(2+) and Ni(2+) in Cu-Ni-EDTA wastewaters were much higher than those in a single heavy metal system. The degradation efficiency of EDTA in Cu-Ni-EDTA was lower than that in a single metal system. In the Cu-Ni-EDTA system, the microwave thermal degradation and the Fenton-like reaction created by Cu catalyzed H2O2 altered the EDTA degradation pathway and increased the pH of the wastewater system, conversely inhibiting residual EDTA degradation. PMID:26398034

  3. Competitive removal of Cu-EDTA and Ni-EDTA via microwave-enhanced Fenton oxidation with hydroxide precipitation.

    PubMed

    Lin, Qintie; Pan, Hanping; Yao, Kun; Pan, Yonggang; Long, Wei

    2015-01-01

    Ethylenediaminetetraacetic acid (EDTA) can form very stable complexes with heavy metal ions, greatly inhibiting conventional metal-removal technologies used in water treatment. Both the oxidation of EDTA and the reduction of metal ions in metal-EDTA systems via the microwave-enhanced Fenton reaction followed by hydroxide precipitation were investigated. The Cu(II)-Ni(II)-EDTA, Cu(II)-EDTA and Ni(II)-EDTA exhibited widely different decomplexation efficiencies under equivalent conditions. When the reaction reached equilibrium, the chemical oxygen demand was reduced by a microwave-enhanced Fenton reaction in different systems and the reduction order from high to low was Cu(II)-Ni(II)-EDTA ≈ Cu(II)-EDTA > Ni(II)-EDTA. The removal efficiencies of both Cu(2+) and Ni(2+) in Cu-Ni-EDTA wastewaters were much higher than those in a single heavy metal system. The degradation efficiency of EDTA in Cu-Ni-EDTA was lower than that in a single metal system. In the Cu-Ni-EDTA system, the microwave thermal degradation and the Fenton-like reaction created by Cu catalyzed H2O2 altered the EDTA degradation pathway and increased the pH of the wastewater system, conversely inhibiting residual EDTA degradation.

  4. Simultaneous determination of EDTA, sorbic acid, and diclofenac sodium in pharmaceutical preparations using high-performance liquid chromatography.

    PubMed

    Heydari, Rouhollah; Shamsipur, Mojtaba; Naleini, Nasim

    2013-06-01

    A simple high-performance liquid chromatographic method for simultaneous determination of ethylenediaminetetraacetic acid (EDTA), sorbic acid, and diclofenac sodium was developed and validated. Separation was achieved on a C(18) column (10 cm×4.6 mm) using gradient elution. The mobile phase consisted of acetonitrile-ammonium dihydrogen phosphate buffer solution (0.01 M, pH=2.5, containing 0.8% tetra-n-butyl ammonium hydroxide). The detector wavelength was set at 254 nm. Under these conditions, separation of three compounds was achieved in less than 10 min. The effect of two metal salts and metal concentration on peak area of EDTA was investigated. The pH effect on retention of EDTA and sorbic acid was studied. The method showed linearity for EDTA, sorbic acid, and diclofenac in the ranges of 2.5-100.0, 5.0-200.0, and 20.0-120.0 μg/mL, respectively. The within- and between-day relative standard deviations ranged from 0.52 to 1.94%, 0.50 to 1.34%, and 0.78 to 1.67% for EDTA, sorbic acid, and diclofenac, respectively. The recovery of EDTA, sorbic acid, and diclofenac from pharmaceutical preparation ranged from 96.0-102.0%, 99.7-101.5%, to 97.0-102.5%, respectively. To the best of our knowledge, this is the first report about simultaneous determination of EDTA, sorbic acid, and diclofenac.

  5. Influence of ethylenediaminetetraacetic acid (EDTA) on the on the ability of fatty acids to inhibit the growth of bacteria associated with poultry processing.

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The effect of ethylenediaminetetraacetic acid (EDTA) on the bactericidal activity of alkaline salts of fatty acids was examined. A 0.5 M concentration of caproic, caprylic, capric, and lauric acids was dissolved in 1.0 M potassium hydroxide (KOH), and then supplemented with 0, 5, or 10 mM of EDTA. T...

  6. [Determination of residual aluminium Ion in Huoxiang Zhengqi pellets by GFAAS with EDTA complexation extraction].

    PubMed

    Wang, Xue-Na; Ran, Cong-Cong; Li, Qing-Lian; Du, Chao-Hui; Jiang, Ye

    2015-06-01

    To establish an EDTA complexation extraction pretreatment combining with GFAAS method for the determination of residual aluminium ion in Huoxiang zhengqi pellets without digestive treatment, systematical investigation was made on sample preparation, and EDTA was used for the complexation extraction of residual aluminium ion in samples. The pH, concentration and volume of extraction solution, the temperature and time of microwave extraction, and graphite furnace temperature program were investigated. The results were compared with the microwave digestion. It was showed that, 0.1 g of sample weight was added in 20 mL 0.05 mol x L(-1) EDTA solution (pH 3.5), followed by heating at 150 degrees C for 10 min in the microwave extraction device. The determination of GFAAS was performed at optimized detection wavelength (257.4 nm) as well as graphite furnace temperature program, the detection limits and quantification limits were 2.37 μg x L(-1) and 7.89 μg x L(-1), respectively. The precision (RSD) was less than 2.3%. The average recovery was 96.9% -101%. The present method is easy, rapid and accurate for the determination of residual aluminium ion in Huoxiang zhengqi pellets.

  7. Influence of variable chemical conditions on EDTA-enhanced transport of metal ions in mildly acidic groundwater

    USGS Publications Warehouse

    Kent, D.B.; Davis, J.A.; Joye, J.L.; Curtis, G.P.

    2008-01-01

    Adsorption of Ni and Pb on aquifer sediments from Cape Cod, Massachusetts, USA increased with increasing pH and metal-ion concentration. Adsorption could be described quantitatively using a semi-mechanistic surface complexation model (SCM), in which adsorption is described using chemical reactions between metal ions and adsorption sites. Equilibrium reactive transport simulations incorporating the SCMs, formation of metal-ion-EDTA complexes, and either Fe(III)-oxyhydroxide solubility or Zn desorption from sediments identified important factors responsible for trends observed during transport experiments conducted with EDTA complexes of Ni, Zn, and Pb in the Cape Cod aquifer. Dissociation of Pb-EDTA by Fe(III) is more favorable than Ni-EDTA because of differences in Ni- and Pb-adsorption to the sediments. Dissociation of Ni-EDTA becomes more favorable with decreasing Ni-EDTA concentration and decreasing pH. In contrast to Ni, Pb-EDTA can be dissociated by Zn desorbed from the aquifer sediments. Variability in adsorbed Zn concentrations has a large impact on Pb-EDTA dissociation.

  8. New water soluble heterometallic complex showing unpredicted coordination modes of EDTA

    NASA Astrophysics Data System (ADS)

    Mudsainiyan, R. K.; Jassal, A. K.; Chawla, S. K.

    2015-10-01

    A mesoporous 3D polymeric complex (I) having formula {[Zr(IV)O-μ3-(EDTA)Fe(III)OH]·H2O}n has been crystallized and characterized by various techniques. Single-crystal X-ray diffraction analysis revealed that complex (I) crystallized in chiral monoclinic space group Cc (space group no. 9) with unexpected coordination modes of EDTA and mixture of two transition metal ions. In this complex, the coordination number of Zr(IV) ion is seven where four carboxylate oxygen atoms, two nitrogen atoms, one oxide atom are coordinating with Zr(IV). Fe(III) is four coordinated and its coordination environment is composed of three different carboxylic oxygen atoms from three different EDTA and one oxygen atom of -OH group. The structure consists of 4-c and 16-c (2-nodal) net with new topology and point symbol for net is (336·454·530)·(36). TGA study and XRPD pattern showed that the coordination polymer is quite stable even after losing water molecule and -OH ion. Quenching behavior in fluorescence of ligand is observed by complexation with transition metal ions is due to n-π* transition. The SEM micrograph shows the morphology of complex (I) exhibits spherical shape with size ranging from 50 to 280 nm. The minimum N2 (SBET=8.7693 m2/g) and a maximum amount of H2 (high surface area=1044.86 m2/g (STP)) could be adsorbed at 77 K. From DLS study, zeta potential is calculated i.e. -7.94 shows the negative charges on the surface of complex. Hirshfeld surface analysis and fingerprint plots revealed influence of weak or non bonding interactions in crystal packing of complex.

  9. Effect of EDTA, EDDS, NTA and citric acid on electrokinetic remediation of As, Cd, Cr, Cu, Ni, Pb and Zn contaminated dredged marine sediment.

    PubMed

    Song, Yue; Ammami, Mohamed-Tahar; Benamar, Ahmed; Mezazigh, Salim; Wang, Huaqing

    2016-06-01

    In recent years, electrokinetic (EK) remediation method has been widely considered to remove metal pollutants from contaminated dredged sediments. Chelating agents are used as electrolyte solutions to increase metal mobility. This study aims to investigate heavy metal (HM) (As, Cd, Cr, Cu, Ni, Pb and Zn) mobility by assessing the effect of different chelating agents (ethylenediaminetetraacetic acid (EDTA), ethylenediaminedisuccinic acid (EDDS), nitrilotriacetic acid (NTA) or citric acid (CA)) in enhancing EK remediation efficiency. The results show that, for the same concentration (0.1 mol L(-1)), EDTA is more suitable to enhance removal of Ni (52.8 %), Pb (60.1 %) and Zn (34.9 %). EDDS provides effectiveness to increase Cu removal efficiency (52 %), while EDTA and EDDS have a similar enhancement removal effect on As EK remediation (30.5∼31.3 %). CA is more suitable to enhance Cd removal (40.2 %). Similar Cr removal efficiency was provided by EK remediation tests (35.6∼43.5 %). In the migration of metal-chelate complexes being directed towards the anode, metals are accumulated in the middle sections of the sediment matrix for the tests performed with EDTA, NTA and CA. But, low accumulation of metal contamination in the sediment was observed in the test using EDDS. PMID:26782321

  10. Evidence that Bacterial ABC-Type Transporter Imports Free EDTA for Metabolism

    SciTech Connect

    Zhang, Hua; Herman, Jacob P.; Bolton, Harvey; Zhang, Zhicheng; Clark, Sue B.; Xun, Luying

    2007-11-01

    Ethylenediaminetetraacetic acid (EDTA), a common chelating agent, is becoming a major organic pollutant in the form of metal-EDTA complexes in surface waters, partly due to its recalcitrance to biodegradation. Even an EDTA-degrading bacterium BNC1 does not degrade stable metal-EDTA complexes. An ABC-type transporter was identified for possible uptake of EDTA because the transporter genes and EDTA monooxygenase gene were expressed in a single operon in BNC1. The ABC-type transporter had a periplasmic binding protein (EppA) that should confer the substrate specificity for the transporter; therefore, EppA was produced in Escherichia coli,purified, and characterized. EppA was shown to bind free EDTA with a dissociation constant as low as 25 nM by using isothermal titration calorimetry. When unstable metal-EDTA complexes, e.g. MgEDTA2-, were added to the EppA solution, binding was also observed. However, experimental data and theoretical analysis only supported EppA binding of free EDTA. When stable metal-EDTA complexes, e.g. CuEDTA2-, are titrated into the EppA solution, no binding was observed. Since EDTA monooxygenase in the cytoplasm uses some of the stable metal-EDTA complexes as substrates, we suggest that the lack of EppA binding and EDTA uptake are responsible for the failure of BNC1 cells to degrade the stable complexes.

  11. New water soluble heterometallic complex showing unpredicted coordination modes of EDTA

    SciTech Connect

    Mudsainiyan, R.K. Jassal, A.K.; Chawla, S.K.

    2015-10-15

    A mesoporous 3D polymeric complex (I) having formula ([Zr(IV)O-μ{sup 3}-(EDTA)Fe(III)OH]·H{sub 2}O){sub n} has been crystallized and characterized by various techniques. Single-crystal X-ray diffraction analysis revealed that complex (I) crystallized in chiral monoclinic space group Cc (space group no. 9) with unexpected coordination modes of EDTA and mixture of two transition metal ions. In this complex, the coordination number of Zr(IV) ion is seven where four carboxylate oxygen atoms, two nitrogen atoms, one oxide atom are coordinating with Zr(IV). Fe(III) is four coordinated and its coordination environment is composed of three different carboxylic oxygen atoms from three different EDTA and one oxygen atom of –OH group. The structure consists of 4-c and 16-c (2-nodal) net with new topology and point symbol for net is (3{sup 36}·4{sup 54}·5{sup 30})·(3{sup 6}). TGA study and XRPD pattern showed that the coordination polymer is quite stable even after losing water molecule and –OH ion. Quenching behavior in fluorescence of ligand is observed by complexation with transition metal ions is due to n–π⁎ transition. The SEM micrograph shows the morphology of complex (I) exhibits spherical shape with size ranging from 50 to 280 nm. The minimum N{sub 2} (S{sub BET}=8.7693 m{sup 2}/g) and a maximum amount of H{sub 2} (high surface area=1044.86 m{sup 2}/g (STP)) could be adsorbed at 77 K. From DLS study, zeta potential is calculated i.e. −7.94 shows the negative charges on the surface of complex. Hirshfeld surface analysis and fingerprint plots revealed influence of weak or non bonding interactions in crystal packing of complex. - Graphical abstract: The complex (I) crystallized with unexpected coordination modes of EDTA having 4-c, 16-c net with new topology and point symbol is (3{sup 36}·4{sup 54}·5{sup 30})·(3{sup 6}). TGA study and XRPD pattern proved its stability with high preference of H{sub 2} uptake by complex. - Highlights: • 3D complex

  12. Comparison of EDTA- and citric acid-enhanced phytoextraction of heavy metals in artificially metal contaminated soil by Typha angustifolia.

    PubMed

    Muhammad, Dawood; Chen, Fei; Zhao, Jing; Zhang, Guoping; Wu, Feibo

    2009-08-01

    A pot experiment was conducted to study the performance of EDTA and citric acid (CA) addition in improving phytoextraction of Cd, Cu, Pb, and Cr from artificially contaminated soil by T. angustifolia. T. angustifolia showed the remarkable resistance to heavy metal toxicity with no visual toxic symptom including chlorosis and necrosis when exposed to metal stress. EDTA-addition significantly reduced plant height and biomass, compared with the control, and stunted plant growth, while 2.5 and 5 mM CA addition induced significant increases in root dry weight. EDTA, and 5 and 10 mM CA significantly increased shoot Cd, Pb, and Cr concentrations compared with the control, with EDTA being more effective. At final harvest, the highest shoot Cd, Cr, and Pb concentrations were recorded in the treatment of 5 mM EDTA addition, while maximal root Pb concentration was found at the 2.5 mM CA treatment. However, shoot Cd accumulation in the 10 mM CA treatment was 36.9% higher than that in 2.5 mM EDTA, and similar with that in 10 mM EDTA. Shoot Pb accumulation was lower in 10 mM CA than that in EDTA treatments. Further, root Cd, Cu, and Pb accumulation of CA treatments and shoot Cr accumulation in 5 or 10 mM CA treatments were markedly higher than that of control and EDTA treatments. The results also showed that EDTA dramatically increased the dissolution of Cu, Cr, Pb, and Cd in soil, while CA addition had less effect on water-soluble Cu, Cr, and Cd, and no effect on Pb levels. It is suggested that CA can be a good chelator candidate for T. angustifolia used for environmentally safe phytoextraction of Cd and Cr in soils.

  13. Synthesis of Metal Oxide Particles Using Reaction Route from Rare-Earth Metal-EDTA Complexes

    NASA Astrophysics Data System (ADS)

    Komatsu, Keiji; Tsuchiya, Takaaki; Hasebe, Yasuhiro; Sekiya, Tetsuo; Toyama, Ayumu; Nakamura, Atsushi; Akasaka, Hiroki; Saitoh, Hidetoshi

    2014-06-01

    Highly dense, spherical yttria (Y2O3) and erbia (Er2O3) particles were synthesized from their corresponding metal-ethylenediaminetetraacetic (EDTA) complexes. The EDTA·Y·H and EDTA·Er·H complexes were prepared in powdered form. These complexes were used as the staring materials for synthesis of the Y2O3 and Er2O3 particles. The particles were synthesized using an H2-O2 flame produced with a commercial flame spray apparatus. Crystalline structure, surface and cross-sectional morphologies, and elemental distribution of the synthesized particles were investigated. It was confirmed that the crystalline phases of the Y2O3 and Er2O3 particles were homogeneous. In addition, the elemental distribution of the particles was uniform. These results indicate that dense, spherical particles of Y2O3 and Er2O3 have been synthesized with EDTA·Y·H and EDTA·Er·H complexes, respectively.

  14. Inhibition of Listeria monocytogenes and Salmonella by combinations of oriental mustard, malic acid, and EDTA.

    PubMed

    Olaimat, Amin N; Holley, Richard A

    2014-04-01

    The antimicrobial activities of oriental mustard extract alone or combined with malic acid and EDTA were investigated against Salmonella spp. or Listeria monocytogenes at different temperatures. Five strain Salmonella or L. monocytogenes cocktails were separately inoculated in Brain Heart Infusion broth containing 0.5% (w/v) aqueous oriental mustard extract and incubated at 4 °C to 21 °C for 21 d. For inhibitor combination tests, Salmonella Typhimurium 02:8423 and L. monocytogenes 2-243 were individually inoculated in Mueller Hinton broth containing the mustard extract with either or both 0.2% (w/v) malic acid and 0.2% (w/v) EDTA and incubated at 10 °C or 21 °C for 10 to 14 d. Mustard extract inhibited growth of the L. monocytogenes cocktail at 4 °C up to 21 d (2.3 log10 CFU/mL inhibition) or at 10 °C for 7 d (2.4 log10 CFU/mL inhibition). Salmonella spp. viability was slightly, but significantly reduced by mustard extract at 4 °C by 21 d. Although hydrolysis of sinigrin in mustard extract by both pathogens was 2 to 6 times higher at 21 °C than at 4 °C to 10 °C, mustard was not inhibitory at 21 °C, perhaps because of the instability of its hydrolysis product (allyl isothiocyanate). At 21 °C, additive inhibitory effects of mustard extract with EDTA or malic acid led to undetectable levels of S. Typhimurium and L. monocytogenes by 7 d and 10 d, respectively. At 10 °C, S. Typhimurium was similarly susceptible, but combinations of antimicrobials were not more inhibitory to L. monocytogenes than the individual agents.

  15. On the Anomalous Adsorption of [Pd(Edta)]**2- at the Water/Goethite Interface: Spectroscopic Evidence for Two Types of Surface Complexes

    SciTech Connect

    Kaplun, M.; Nordin, A.; Persson, P.

    2009-05-18

    The structure of palladium(II) ethylenediaminetetraacetate (edta) in aqueous solutions and its adsorption on the surface of goethite ({alpha}-FeOOH) were studied using extended X-ray absorption fine structure spectroscopy and attenuated total reflection Fourier transform infrared spectroscopy. The obtained results show that in aqueous solutions, Pd-edta exists as a 1:1 complex, [Pd(edta)]{sup 2-}, with edta acting as a quadridentate ligand. On the surface of goethite, [Pd(edta)]{sup 2-} forms two different types of complexes over a pH range of 3.40-8.12. At pH < 5, [Pd(edta)]{sup 2-} adsorbs as an outer-sphere species with possible hydrogen bonding. At higher pH values, the formation of inner-sphere complexes of the cation-type sets in after a cleavage of one glycinate ring and the formation of an (edta)Pd-O-Fe linkage.

  16. Apical microleakage of different root canal sealers after use of maleic acid and EDTA as final irrigants.

    PubMed

    Ulusoy, Ozgür Ilke; Nayir, Yelda; Celik, Kezban; Yaman, Sis Darendeliler

    2014-01-01

    This study aimed to compare the effects of ethylenediaminetetraacetic acid (EDTA) and maleic acid (MA) on the sealing ability of various root canal sealers. Eighty root canals were instrumented and irrigated with either EDTA or MA. They were divided into eight experimental groups and obturated as follows: Group 1: MA + Hybrid Root SEAL/gutta-percha. Group 2: EDTA + Hybrid Root SEAL/gutta-percha. Group 3: MA + iRoot SP/gutta-percha. Group 4: EDTA + iRoot SP/gutta-percha. Group 5: MA + EndoREZ/EndoREZ points. Group 6: EDTA + EndoREZ/EndoREZ points. Group 7: MA + AH Plus/gutta-percha. Group 8: EDTA + AH Plus/gutta-percha. Another ten roots were used as negative and positive controls. The microleakage of each sample was measured at 2-min intervals for 8 min using the fluid filtration method. Data were statistically analyzed with one-way ANOVA, post-hoc Tukey, and paired-samples t tests. The minimum microleakage values were obtained from the teeth obturated with AH Plus and EndoREZ selaers (p < 0.001). The samples with Hybrid Root SEAL showed the maximum leakage (p < 0.001). There were significant differences between the groups irrigated with MA or EDTA in terms of microleakage (p < 0.05). Use of MA resulted in higher microleakage values compared with those using EDTA. The type of final irrigation solution seems to influence the postobturation apical seal. Use of AH Plus and EndoREZ sealers showed better sealing ability compared with IRoot SP and Hybrid Root SEAL.

  17. Efficacy of different final irrigant activation protocols on smear layer removal by EDTA and citric acid.

    PubMed

    Herrera, Daniel R; Santos, Zarina T; Tay, Lidia Y; Silva, Emmanuel J; Loguercio, Alessandro D; Gomes, Brenda P F A

    2013-04-01

    The aim of this study was to evaluate the influence of different activation protocols for chelating agents used after chemo-mechanical preparation (CMP), for smear layer (SL) removal. Forty-five single-rooted human premolars with straight canals and fully formed apex were selected. The specimens were randomly divided into three groups depending on the chelating agent used for smear layer removal: distilled water (DW, control group); 17% ethylenediaminetetraacetic acid (EDTA); and 10% citric acid (CA). Each group was further divided into three subgroups according to the activation protocol used: no-activation (NA), manual dynamic activation (MDA), or sonic activation (SA). After CMP, all specimens were sectioned and processed for observation of the apical thirds by using scanning electron microscopy (SEM). Two calibrated evaluators attributed scores to each specimen. The differences between activation protocols were analyzed with Kruskal-Wallis and Mann-Whitney U tests. Friedman and Wilcoxon signed rank tests were used for comparison between each root canal third. When chelating agents were activated, either by MDA or SA, it was obtained the best cleaning results with no significant difference between EDTA and CA (P > 0.05). Sonic activation showed the best results when root canal thirds were analyzed, in comparison to MDA and NA groups (P < 0.05). The activation of chelating agents, independent of the protocol used, benefits smear layer removal from root canals.

  18. Removal of toxic Co-EDTA complex by a halophilic solar-salt-pan isolate Pseudomonas aeruginosa SPB-1.

    PubMed

    Paraneeiswaran, A; Shukla, Sudhir K; Subba Rao, T; Prashanth, K

    2014-01-01

    In this study, a promising bioremediation approach was developed to remove [Co(III)-EDTA](-) complex that is generated during the waste management process. Though several studies have been reported on bioremediation of cobalt, the removal of [Co(III)-EDTA](-) complex has not been tested. A [Co(III)-EDTA](-) resistant bacterium, Pseudomonas aeruginosa SPB-1 was isolated from the solar-salt-pan and physical parameters were optimized for its growth. The various studies showed that the removal of [Co(III)-EDTA](-) from the bulk liquid was due to the adsorption of the complex by the biomass. Using absorption/desorption isotherm over a range of pH (1-8), the maximum adsorption of [Co(III)-EDTA](-) was found to be at pH 7.0 and maximum desorption from the biomass occurred at pH 1.0, thus rendering an ion exchange property to P. aeruginosa SPB-1 biomass. P. aeruginosa SPB-1 biomass could be used as bio-resin that showed 80.4±3.27% adsorption capacity up to fourth cycle and the biomass was viable till the ninth cycle with 10.5±7.3% adsorption. Radiation tolerance potential i.e. D10 value for the strain was found to be ~300 Gy, which suggests the potential use of the bacterium in bioremediation of moderately active nuclear waste.

  19. Cytotoxic effects of 10% citric acid and EDTA-T used as root canal irrigants: an in vitro analysis.

    PubMed

    Sceiza, M F; Daniel, R L; Santos, E M; Jaeger, M M

    2001-12-01

    EDTA-T and 10% citric acid used as root canal irrigants lead to more visible dentinal tubules than 5% sodium hypochlorite associated with 3% hydrogen peroxide. However, these cleansing agents must be compatible with apical periodontal tissue. We analyzed the cytotoxicity of 10% citric acid and EDTA-T in cultured fibroblasts using Trypan blue. The solutions were diluted to 1%, 0.1%, and 0.01% and applied to NIH 3T3 cell cultures. Cells grown on fresh DMEM served as a control. After 0, 6, 12, and 24 h (short-term assay, viability) and 1, 3, 5, and 7 days (long-term assay, survival), the cells were counted using a hemocytometer. In short-term tests, cell viability ranged from 85% to 99% for all experimental groups with no statistical differences when compared with control cultures, except for the group treated with 1% EDTA-T, which caused a progressive decrease in cell viability. In long-term tests, all cultures increased in number from day 1 to the end of the experimental period, showing no inhibition of cell proliferation, except for the cultures treated with 1% EDTA-T, which totally prevented cell growth. All dilutions of 10% citric acid were more biocompatible than EDTA-T. Cultures treated with citric acid had a higher percentage of viable cells in the short-term assays, and the cells retained their self-renewal capacity.

  20. Effects of simulated acid rain, EDTA, or their combination, on migration and chemical fraction distribution of extraneous metals in Ferrosol.

    PubMed

    Wen, Fang; Hou, Hong; Yao, Na; Yan, Zengguang; Bai, Liping; Li, Fasheng

    2013-01-01

    A laboratory repacked soil-leaching column experiment was conducted to study the effects of simulated acid rain or EDTA by themselves or in combination, on migration and chemical speciation distribution of Pb and its alternative rare metals including Ag, Bi, In, Sb, and Sn. Experimental results demonstrate that leaching with simulated acid rain promoted the migration of Bi, In and Pb, and their migration reached down to 8 cm in the soil profile, no enhancement of Sb, Ag or Sn migration was observed. Addition of EDTA significantly enhanced the migration of all six metals, especially Bi, In and Pb. The migration of metals was in the order Pb>Bi>In>Sb>Sn>Ag. The individual and combined effects of acid rain and EDTA increased the environmental risk of metals, by increasing the soluble content of metals in soil solutions and the relative distribution of the exchangeable fraction. Leaching risks of Bi, In and Pb were higher than other three metals.

  1. Effect of EDTA and citric acid on phytoremediation of Cr- B[a]P-co-contaminated soil.

    PubMed

    Chigbo, Chibuike; Batty, Lesley

    2013-12-01

    Polycyclic aromatic hydrocarbons and heavy metals in the environment are a concern, and their removal to acceptable level is required. Phytoremediation, the use of plants to treat contaminated soils, could be an interesting alternative to conventional remediation processes. This work evaluates the role of single and combined applications of chelates to single or mixed Cr + benzo[a]pyrene (B[a]P)-contaminated soil. Medicago sativa was grown in contaminated soil and was amended with 0.3 g citric acid, 0.146 g ethylenediaminetetraacetic acid (EDTA), or their combination for 60 days. The result shows that in Cr-contaminated soil, the application of EDTA + citric acid significantly (p<0.05) decreased the shoot dry matter of M. sativa by 55 % and, as such, decreased the Cr removal potential from the soil. The soluble Cr concentration in single Cr or Cr + B[a]P-contaminated soil was enhanced with the amendment of all chelates; however, only the application of citric acid in Cr-contaminated soil (44 %) or EDTA and EDTA + citric acid in co-contaminated soil increased the removal of Cr from the soil (34 and 54 %, respectively). The dissipation of B[a]P in single B[a]P-contaminated soil was effective even without planting and amendment with chelates, while in co-contaminated soil, it was related to the application of either EDTA or EDTA + citric acid. This suggests that M. sativa with the help of chelates in single or co-contaminated soil can be effective in phytoextraction of Cr and promoting the biodegradation of B[a]P.

  2. Resin–dentin bonds to EDTA-treated vs. acid-etched dentin using ethanol wet-bonding

    PubMed Central

    Sauro, Salvatore; Toledano, Manuel; Aguilera, Fatima Sánchez; Mannocci, Francesco; Pashley, David H.; Tay, Franklin R.; Watson, Timothy F.; Osorio, Raquel

    2013-01-01

    Objective To compare resin–dentin bond strengths and the micropermeability of hydrophobic vs. hydrophilic resins bonded to acid-etched or EDTA-treated dentin, using the ethanol wet-bonding technique. Methods Flat dentin surfaces from extracted human third molars were conditioned before bonding with: 37% H3PO4 (15 s) or 0.1 M EDTA (60 s). Five experimental resin blends of different hydrophilicities and one commercial adhesive (SBMP: Scotchbond Multi-Purpose) were applied to ethanol wet-dentin (1 min) and light-cured (20 s). The solvated resins were used as primers (50% ethanol/50% comonomers) and their respective neat resins were used as the adhesive. The resin-bonded teeth were stored in distilled water (24 h) and sectioned in beams for microtensile bond strength testing. Modes of failure were examined by stereoscopic light microscopy and SEM. Confocal tandem scanning microscopy (TSM) interfacial characterization and micropermeability were also performed after filling the pulp chamber with 1 wt% aqueous rhodamine-B. Results The most hydrophobic resin 1 gave the lowest bond strength values to acid-etched dentin and all beams failed prematurely when the resin was applied to EDTA-treated dentin. Resins 2 and 3 gave intermediate bond strengths to both conditioned substrates. Resin 4, an acidic hydrophilic resin, gave the highest bond strengths to both EDTA-treated and acid-etched dentin. Resin 5 was the only hydrophilic resin showing poor resin infiltration when applied on acid-etched dentin. Significance The ethanol wet-bonding technique may improve the infiltration of most of the adhesives used in this study into dentin, especially when applied to EDTA-treated dentin. The chemical composition of the resin blends was a determining factor influencing the ability of adhesives to bond to EDTA-treated or 37% H3PO4 acid-etched dentin, when using the ethanol wet-bonding technique in a clinically relevant time period. PMID:20074787

  3. EDTA and HCl leaching of calcareous and acidic soils polluted with potentially toxic metals: remediation efficiency and soil impact.

    PubMed

    Udovic, Metka; Lestan, Domen

    2012-07-01

    The environmental risk of potentially toxic metals (PTMs) in soil can be diminished by their removal. Among the available remediation techniques, soil leaching with various solutions is one of the most effective but data about the impact on soil chemical and biological properties are still scarce. We studied the effect of two common leaching agents, hydrochloric acid (HCl) and a chelating agent (EDTA) on Pb, Zn, Cd removal and accessibility and on physico-chemical and biological properties in one calcareous, pH neutral soil and one non-calcareous acidic soil. EDTA was a more efficient leachant compared to HCl: up to 133-times lower chelant concentration was needed for the same percentage (35%) of Pb removal. EDTA and HCl concentrations with similar PTM removal efficiency decreased PTM accessibility in both soils but had different impacts on soil properties. As expected, HCl significantly dissolved carbonates from calcareous soil, while EDTA leaching increased the pH of the acidic soil. Enzyme activity assays showed that leaching with HCl had a distinctly negative impact on soil microbial and enzyme activity, while leaching with EDTA had less impact. Our results emphasize the importance of considering the ecological impact of remediation processes on soil in addition to the capacity for PTM removal.

  4. The influence of ethylenediamine tetra acetic acid (EDTA) on the transformation and solubility of metallic palladium and palladium(II) oxide in the environment.

    PubMed

    Zereini, Fathi; Wiseman, Clare L S; Vang, My; Albers, Peter; Schneider, Wolfgang; Schindl, Roland; Leopold, Kerstin

    2015-05-01

    The environmental occurrence of elevated concentrations of platinum (Pt), palladium (Pd) and rhodium (Rh) from automotive catalytic converters has been well-documented. Limited information exists regarding their chemical behavior post-emission, however, especially in the presence of commonly occurring complexing agents. The purpose of this study is to examine the influence of ethylenediamine tetra acetic acid (EDTA) on the possible environmental transformation and solubility of Pd by conducting batch experiments using metallic palladium (Pd black) and palladium(ii) oxide (PdO). Changes in the particle surface chemistry of treated samples were analyzed using X-ray Photoelectron Spectroscopy (XPS) and Transition Electron Microscopy/Energy Dispersive X-ray Spectrometry (TEM/EDX) techniques. Metallic palladium was partially transformed into PdOx (x < 1), while PdO remained largely unaffected. The pH of EDTA solutions was observed to modulate Pd solubility, with Pd black demonstrating a higher solubility compared to PdO. Solubility was also found to increase with a corresponding increase in the strength of EDTA solution concentrations, as well as with the length of extraction time. The overall solubility of Pd remained relatively low for most samples (<1 wt%). A dissolution rate of 2.01 ± 0.17 nmol m(-2) h(-1) was calculated for Pd black in 0.1 M EDTA (pH 7). In contrast to previously held assumptions about the environmental immobility of Pd, small amounts of this element emitted in metallic form are likely to be soluble in the presence of complexing agents such as EDTA.

  5. Photodynamic therapy with 5-aminoolevulinic acid-induced porphyrins and DMSO/EDTA for basal cell carcinoma

    NASA Astrophysics Data System (ADS)

    Warloe, Trond; Peng, Qian; Heyerdahl, Helen; Moan, Johan; Steen, Harald B.; Giercksky, Karl-Erik

    1995-03-01

    Seven hundred sixty three basal cell carcinomas (BCCs) in 122 patients were treated by photodynamic therapy by 5-aminolevulinic acid (ALA) in cream topically applied, either alone, in combination with dimethyl sulphoxide (DMSO) and ethylenediaminetetraacetic acid disodium salt (EDTA), or with DMSO as a pretreatment. After 3 hours cream exposure 40 - 200 Joules/cm2 of 630 nm laser light was given. Fluorescence imaging of biopsies showed highly improved ALA penetration depth and doubled ALA-induced porphyrin production using DMSO/EDTA. Treatment response was recorded after 3 months. After a single treatment 90% of 393 superficial lesions responded completely, independent of using DMSO/EDTA. In 363 nodulo-ulcerative lesions the complete response rate increased from 67% to above 90% with DMSO/EDTA for lesions less than 2 mm thickness and from 34% to about 50% for lesions thicker than 2 mm. Recurrence rate observed during a follow-up period longer than 12 months was 2 - 5%. PDT of superficial thin BCCs with ALA-induced porphyrins and DMSO/EDTA equals surgery and radiotherapy with respect to cure rate and recurrence. Cosmetic results of ALA-based PDT seemed to be better than those after other therapies. In patients with the nevoid BCC syndrome the complete response rate after PDT was far lower.

  6. EDTA assisted synthesis of hydroxyapatite nanoparticles for electrochemical sensing of uric acid.

    PubMed

    Kanchana, P; Sekar, C

    2014-09-01

    Hydroxyapatite nanoparticles have been synthesized using EDTA as organic modifier by a simple microwave irradiation method and its application for the selective determination of uric acid (UA) has been demonstrated. Electrochemical behavior of uric acid at HA nanoparticle modified glassy carbon electrode (E-HA/GCE) has been investigated by electrochemical impedance spectroscopy (EIS), cyclic voltammetry (CV), linear sweep voltammetry (LSV) and amperometry. The E-HA modified electrode exhibits efficient electrochemical activity towards uric acid sensing without requiring enzyme or electron mediator. Amperometry studies revealed that the fabricated electrode has excellent sensitivity for uric acid with the lowest detection limit of 142 nM over a wide concentration range from 1 × 10(-7) to 3 × 10(-5)M. Moreover, the studied E-HA modified GC electrode exhibits a good reproducibility and long-term stability and an admirable selectivity towards the determination of UA even in the presence of potential interferents. The analytical performance of this sensor was evaluated for the detection of uric acid in human urine and blood serum samples.

  7. Remediation of metal contaminated soil by EDTA incorporating electrochemical recovery of metal and EDTA

    SciTech Connect

    Allen, H.E.; Chen, P.H. )

    1993-11-01

    Removal of toxic heavy metals from a soil matrix by the addition of ethylenediamine tetraacetic acid (EDTA) is an effective means of remediation. The liquid stream containing the metal and chelating agent is amenable to further treatment by electrolysis in which the metal can be separated from the chelating agent. This provides a separated metal than can be removed for reuse or treated for final disposal by conventional technologies and a reclaimed EDTA stream that can be used again for treatment of contaminated soil. Under the diffusion controlled conditions of polarography or voltammetry, the authors observed reduction of cadmium, copper and lead ions and their protonated EDTA complexes (MHY[sup [minus

  8. In vitro genotoxicity and cytotoxicity in murine fibroblasts exposed to EDTA, NaOCl, MTAD and citric acid.

    PubMed

    Marins, Juliana Soares Roter; Sassone, Luciana Moura; Fidel, Sandra Rivera; Ribeiro, Daniel Araki

    2012-01-01

    The aim of the present study was to evaluate the capacity of some root canal irrigants to induce genetic damage and/or cellular death in vitro. Murine fibroblast cells were exposed to ethylenediaminetetraacetic acid (EDTA), sodium hypochlorite (NaOCl), MTAD™ and citric acid in increasing concentrations for 3 h at 37ºC. The negative control group was treated with vehicle control (phosphate buffer solution - PBS) for 3 h at 37°C, and the positive control group was treated with methylmetanesulfonate, 1 μM. for 3 h at 37°C. Cytotoxicity was assessed by the trypan blue test and genotoxicity was evaluated by the single cell gel (comet) assay. The results showed that exposure to 2.5% and 5% NaOCl and 8.5% citric acid resulted in a significant cytotoxic effect. NaOCl, EDTA and citric acid did not produce genotoxic effects with respect to the comet assay data for all evaluated concentrations. Although MTAD was not a cytotoxic agent, it showed significant genotoxic effects at all tested concentrations (ANOVA and Tukey's test; p<0.05). NaOCl, EDTA and citric acid were found to be cytotoxic in a dose-dependent manner, but they were not genotoxic. MTAD did not cause cell death, but presented genotoxic effects.

  9. Gibberellic acid, kinetin, and the mixture indole-3-acetic acid-kinetin assisted with EDTA-induced lead hyperaccumnulation in alfalfa plants.

    PubMed

    López, Martha L; Peralta-Videa, José R; Parsons, Jason G; Benitez, Tenoch; Gardea-Torresdey, Jorge L

    2007-12-01

    There are a few plant species considered potential hyperaccumulators for heavy metals, particularly lead (Pb). In this study, alfalfa plants grown in hydroponics were exposed to Pb at 40 mg/L, ethylenediaminetetraacetic acid (EDTA) equimolar to Pb, and 1, 10, and 100 microM concentrations of the phytohormones indole-3-acetic acid (IAA), gibberellic acid (GA), and kinetin (KN) and a mixture of IAA and KN at 100 microM each. Metal quantification by inductively coupled plasma/optical emission spectroscopy demonstrated that plants treated with Pb/EDTA plus KN at 1, 10, and 100 microM increased the Pb concentration in alfalfa leaves (compared to Pb alone) by factors of 17, 43, and 67, respectively, and by factors of 2, 5, and 8, respectively, compared to the Pb/EDTA treatment. The correlation coefficient between the Pb concentration in leaves and the concentrations of KN in the medium was 0.9993. In addition, the leaves of plants exposed to a Pb/EDTA/100 microM IAA-KN mixture had approximately 9500 mg of Pb/kg of dry weight, demonstrating that non-Pb hyperaccumulating plants could hyperaccumulate Pb when treated with EDTA and a mixture of IAA-KN. The X-ray absorption spectroscopic studies demonstrated that the absorption and translocation of Pb was in the same oxidation state as the supplied Pb(II).

  10. Influence of the selective EDTA derivative phenyldiaminetetraacetic acid on the speciation and extraction of heavy metals from a contaminated soil.

    PubMed

    Zhang, Tao; Wei, Hang; Yang, Xiu-Hong; Xia, Bing; Liu, Jun-Min; Su, Cheng-Yong; Qiu, Rong-Liang

    2014-08-01

    The development of more selective chelators for the washing of heavy metal contaminated soil is desirable in order to avoid excessive dissolution of soil minerals. Speciation and mobility of Cu, Zn, Pb, and Ni in a contaminated soil washed with phenyldiaminetetraacetic acid (PDTA), a derivative of EDTA, were investigated by batch leaching test using a range of soil washing conditions followed by sequential extraction. With appropriate washing conditions, PDTA significantly enhanced extraction of Cu from the contaminated soil. The primary mechanisms of Cu extraction by PDTA were complexation-promoted dissolution of soil Cu and increased dissolution of soil organic matter (SOM). PDTA showed high selectivity for Cu(II) over soil component cations (Ca(II), Mg(II), Fe(III), Mn(II), Al(III)), especially at lower liquid-to-soil ratios under PDTA deficiency, thus avoiding unwanted dissolution of soil minerals during the soil washing process which can degrade soil structure and interfere with future land use. PDTA-enhanced soil washing increased the exchangeable fractions of Cu, Zn, and Pb and decreased their residual fractions, compared to their levels in unwashed soil.

  11. Effect of EDTA, HCl, and citric acid on Ca salt removal from Asian (silver) carp scales prior to gelatin extraction.

    PubMed

    Wang, Yan; Regenstein, Joe M

    2009-08-01

    Pretreatments with different chemicals at different concentrations to remove Ca compounds were studied to determine their effects on gelatin extraction from silver carp (Hypophthalmichthys molitrix) scales. During Ca removal with HCl, citric acid, and EDTA, all 3 chemicals were able to decalcify (>90%) scales; however, protein losses with EDTA were lower than with HCl and citric acid (P < 0.05), and protein losses with citric acid were lower than with HCl (P < 0.05). Ca removal with HCl yielded a solution where 4% to 5% of the protein was Hyp, with estimated gelatin losses from 0.9% to 2.5%. After 0.20 mol/L HCl was used for Ca removal, the extracted gelatin solution was 15.4% of the initial scales weight and gave a gel strength of 128 g. After using 1.2 g/L citric acid for Ca removal, the extracted gelatin solution was only 9% of the scales and the gel strength was 97 g. Using 0.20 mol/L EDTA for Ca removal gave a yield of 22% and a gel strength of 152 g. These data suggest that EDTA at 0.20 mol/L provides the best Ca removal with minimal collagen/gelatin removal (estimated gelatin loss was less than 0.013%) during the Ca removal step, and subsequently gave a high gelatin yield and gel strength. Fish gelatin has generally been extracted from fish skins and occasionally fish bones. This article focuses on removing the Ca compounds in fish scales and then producing fish gelatin with a good gel strength and yield. With further studies, this study may help the fish industry to have a new source of fish gelatin for food and pharmaceutical applications.

  12. A new spectrophotometric method for determination of EDTA in water using its complex with Mn(III).

    PubMed

    Andrade, Carlos Eduardo O; Oliveira, André F; Neves, Antônio A; Queiroz, Maria Eliana L R

    2016-11-01

    EDTA is an important ligand used in many industrial products as well as in agriculture, where it is employed to assist in phytoextraction procedures and the absorption of nutrients by plants. Due to its intensive use and recalcitrance, it is now considered an emerging pollutant in water, so there is great interest in techniques suitable for its monitoring. This work proposes a method based on formation of the Mn(III)-EDTA complex after oxidation of the Mn(II)-EDTA complex by PbO2 immobilized on cyanoacrylate spheres. A design of experiments (DOE) based on the Doehlert matrix was used to determine the optimum conditions of the method, and the influence of the variables was evaluated using a multiple linear regression (MLR) model. The optimized method presented a linear response in the range from 0.77 to 100.0μmolL(-1), with analytical sensitivity of 7.7×10(3)Lmol(-1), a coefficient of determination of 0.999, and a limit of detection of 0.23μmolL(-1). The method was applied using samples fortified at different concentration levels, and the recoveries achieved were between 97.0 and 104.9%. PMID:27305647

  13. A new spectrophotometric method for determination of EDTA in water using its complex with Mn(III)

    NASA Astrophysics Data System (ADS)

    Andrade, Carlos Eduardo O.; Oliveira, André F.; Neves, Antônio A.; Queiroz, Maria Eliana L. R.

    2016-11-01

    EDTA is an important ligand used in many industrial products as well as in agriculture, where it is employed to assist in phytoextraction procedures and the absorption of nutrients by plants. Due to its intensive use and recalcitrance, it is now considered an emerging pollutant in water, so there is great interest in techniques suitable for its monitoring. This work proposes a method based on formation of the Mn(III)-EDTA complex after oxidation of the Mn(II)-EDTA complex by PbO2 immobilized on cyanoacrylate spheres. A design of experiments (DOE) based on the Doehlert matrix was used to determine the optimum conditions of the method, and the influence of the variables was evaluated using a multiple linear regression (MLR) model. The optimized method presented a linear response in the range from 0.77 to 100.0 μmol L- 1, with analytical sensitivity of 7.7 × 103 L mol- 1, a coefficient of determination of 0.999, and a limit of detection of 0.23 μmol L- 1. The method was applied using samples fortified at different concentration levels, and the recoveries achieved were between 97.0 and 104.9%.

  14. Effects of simulated acid rain, EDTA, or their combination, on migration and chemical fraction distribution of extraneous metals in Ferrosol.

    PubMed

    Wen, Fang; Hou, Hong; Yao, Na; Yan, Zengguang; Bai, Liping; Li, Fasheng

    2013-01-01

    A laboratory repacked soil-leaching column experiment was conducted to study the effects of simulated acid rain or EDTA by themselves or in combination, on migration and chemical speciation distribution of Pb and its alternative rare metals including Ag, Bi, In, Sb, and Sn. Experimental results demonstrate that leaching with simulated acid rain promoted the migration of Bi, In and Pb, and their migration reached down to 8 cm in the soil profile, no enhancement of Sb, Ag or Sn migration was observed. Addition of EDTA significantly enhanced the migration of all six metals, especially Bi, In and Pb. The migration of metals was in the order Pb>Bi>In>Sb>Sn>Ag. The individual and combined effects of acid rain and EDTA increased the environmental risk of metals, by increasing the soluble content of metals in soil solutions and the relative distribution of the exchangeable fraction. Leaching risks of Bi, In and Pb were higher than other three metals. PMID:22921654

  15. Effect of EDTA and Phosphoric Acid Pretreatment on the Bonding Effectiveness of Self-Etch Adhesives to Ground Enamel

    PubMed Central

    Ibrahim, Ihab M.; Elkassas, Dina W.; Yousry, Mai M.

    2010-01-01

    Objectives: This in vitro study determined the effect of enamel pretreatment with phosphoric acid and ethylenediaminetetraacetic acid (EDTA) on the bond strength of strong, intermediary strong, and mild self-etching adhesive systems. Methods: Ninety sound human premolars were used. Resin composite cylinders were bonded to flat ground enamel surfaces using three self-etching adhesive systems: strong Adper Prompt L-Pop (pH=0.9–1.0), intermediary strong AdheSE (pH=1.6–1.7), and mild Frog (pH=2). Adhesive systems were applied either according to manufacturer instructions (control) or after pretreatment with either phosphoric acid or EDTA (n=10). After 24 hours, shear bond strength was tested using a universal testing machine at a cross-head speed of 0.5 mm/minute. Ultra-morphological characterization of the surface topography and resin/enamel interfaces as well as representative fractured enamel specimens were examined using scanning electron microscopy (SEM). Results: Neither surface pretreatment statistically increased the mean shear bond strength values of either the strong or the intermediary strong self-etching adhesive systems. However, phosphoric acid pretreatment significantly increased the mean shear bond strength values of the mild self-etching adhesive system. SEM examination of enamel surface topography showed that phosphoric acid pretreatment deepened the same etching pattern of the strong and intermediary strong adhesive systems but converted the irregular etching pattern of the mild self-etching adhesive system to a regular etching pattern. SEM examination of the resin/enamel interface revealed that deepening of the etching pattern was consistent with increase in the length of resin tags. EDTA pretreatment had a negligible effect on ultra-morphological features. Conclusions: Use of phosphoric acid pretreatment can be beneficial with mild self-etching adhesive systems for bonding to enamel. PMID:20922162

  16. Two-dimensional layer architecture assembled by Keggin polyoxotungstate, Cu(II)-EDTA complex and sodium linker: Synthesis, crystal structures, and magnetic properties

    SciTech Connect

    Liu Hong; Xu Lin Gao Guanggang; Li Fengyan; Yang Yanyan; Li Zhikui; Sun Yu

    2007-05-15

    Reaction of Keggin polyoxotungstate with copper(II)-EDTA (EDTA=ethylenediamine tetraacetate) complex under mild conditions led to the formation of hybrid inorganic-organic compounds Na{sub 4}(OH)[(Cu{sub 2}EDTA)PW{sub 12}O{sub 40}].17H{sub 2}O (1) and Na{sub 4}[(Cu{sub 2}EDTA)SiW{sub 12}O{sub 40}].19H{sub 2}O (2). The single-crystal X-ray diffraction analyses reveal their two structural features: (1) one-dimensional chain structure consisting of Keggin polyoxotungstate and copper(II)-EDTA complex; (2) Two-dimensional layer architecture assembled by the one-dimensional chain structure and sodium linker. The results of magnetic measurements in the temperature range 300-2 K indicated the existence of ferromagnetic exchange interactions between the Cu{sup II} ions for both compounds. In addition, TGA analysis, IR spectra, and electrochemical properties were also investigated to well characterize these two compounds. - Graphical abstract: Two new polyoxometalate-based hybrids, Na{sub 4}(OH)[Cu{sub 2}(EDTA)PW{sub 12}O{sub 40}].17H{sub 2}O (1) and Na{sub 4}[Cu{sub 2}(EDTA)SiW{sub 12}O{sub 40}].19H{sub 2}O (2), have been synthesized and structurally characterized, which consist of one-dimensional chain structure assembled by Keggin polyoxotungstate and copper(II)-EDTA complex. The chains are further connected to form two-dimensional layer architecture assembled by the one-dimensional chain structure and sodium linker.

  17. Effect of the anticoagulant ethylenediamine tetra-acetic acid (EDTA) on the estimation of pharmacokinetic parameters: A case study with tigecycline and ciprofloxacin.

    PubMed

    Chen, Q; Tung, E C; Ciccotto, S L; Strauss, J R; Ortiga, R; Ramsay, K A; Tang, W

    2008-01-01

    Tigecycline and ciprofloxacin were employed as the model compounds to study the effect of the anticoagulant ethylenediamine tetra-acetic acid (EDTA), which is used during plasma sample preparations, on the determination of pharmacokinetic parameters. The pharmacokinetic parameters were determined in rats following intravenous infusion with blood samples collected in serum separators, with either EDTA- or heparin-coated tubes. The blood-to-plasma (B:P) partition ratio and plasma protein binding were determined in vitro in rat or human blood collected in either EDTA- or heparin-coated tubes. Drug concentrations were quantified by liquid chromatography coupled with tandem mass spectrometry detection (LC-MS/MS) analysis. In tigecycline-treated rats drug concentrations were twofold lower in EDTA plasma, leading to a twofold lower area under plasma concentration-time curve (AUC) and twofold higher plasma clearance values as compared with those obtained from heparin plasma. No differences were noted in the pharmacokinetic parameters obtained from heparin-treated plasma versus serum. The B:P partition ratio and unbound fraction for tigecycline were significantly higher in EDTA-treated blood. When normalized to the B:P partition ratios, the tigecycline blood clearance values were identical between samples collected in EDTA- or heparin-coated tubes. Similar but smaller differences were observed for ciprofloxacin. It was concluded that EDTA might compete with tigecycline and ciprofloxacin for chelating metal ions and thus affect drug partition between blood and plasma compartments, leading to inaccurate measurement of pharmacokinetic parameters in plasma. PMID:17963190

  18. Simultaneous extraction of Cr(VI) and Cu(II) from humic acid with new synthesized EDTA derivatives.

    PubMed

    Zhang, Tao; Wu, Ying-Xin; Huang, Xiong-Fei; Liu, Jun-Min; Xia, Bing; Zhang, Wei-Hua; Qiu, Rong-Liang

    2012-07-01

    Soil washing is one of the few permanent treatment alternatives for removing metal contaminants. Ethylenediaminetetraacetic acid and its salts (EDTA) is very effective at removing cationic metals and has been utilized globally. However it is ineffective for anionic metal contaminants or metals bound to soil organic matter. The simultaneous removal of cationic and anionic metal contaminants by soil washing is difficult due to differences in their properties. The present study evaluated the potential of a washing process using two synthesized EDTA-derivatives, C(6)HEDTA (2,2'-((2-((carboxymethyl)(2-(hexanoyloxy)ethyl)amino)ethyl)azanediyl)diacetic acid) and C(12)HEDTA (2,2'-((2-((carboxymethyl) (2-(dodecanoyloxy)ethyl)amino)ethyl)azanediyl)diacetic acid), which consist of a hydrophilic polycarboxylic moiety and a hydrophobic moiety with a monoalkyl ester group. A series of equilibrium batch experiments at room temperature were conducted to investigate the efficacy of C(6)HEDTA and C(12)HEDTA as extractants for both oxyanion Cr(VI) and cationic Cu(II). Results showed that either C(6)HEDTA or C(12)HEDTA can extract both Cr(VI) and Cu(II) from humic acid simultaneously. However, C(6)HEDTA was less effective for Cr(VI) probably because it has no surface activities to increase solubility of humic acid, like C(12)HEDTA. Extraction of Cr(VI) was mainly attributed to the decreased surface tension and enhanced solubility of organic matter. Extraction of Cu(II) was attributed to both the Cu(II) chelation and enhanced solubility of humic acid. It was demonstrated that the hydrophilic polycarboxylic moiety of C(12)HEDTA chelates cations while the monoalkyl ester group produces surface active properties that enhance the solubility of humic acid.

  19. Effects of Tetracycline, EDTA and Citric Acid Application on Nonfluorosed and Fluorosed Dentin: An In Vitro Study

    PubMed Central

    Sadanand, K.; Vandana, K. L.

    2016-01-01

    Fluorosis is one of the factors that may bring about mineralization changes in teeth. Routine treatment of root biomodification is commonly followed during Periodontal therapy. Background: The Purpose of the present study was to compare and evaluate the morphological changes in fluorosed and nonfluorosed root dentin subsequent to the application of Tetracycline, EDTA and Citric acid. Both fluorosed and nonfluorosed teeth comprising of periodontally healthy and diseased were included in this study. Method: Each of them was grouped into Tetracycline Hydrochloride, EDTA and Citric acid treatment groupes. Using scanning electron microscope (SEM), the photomicrographs of dentin specimens were obtained. Results: Showed that there was no significant difference in exposure of number of tubules in different groups, while significant increase in the tubular width and tubular surface area was seen in fluorosed healthy, followed by fluorosed diseased groups, nonfluorosed healthy and nonfluorosed diseased groups after root biomodification procedure using various root conditioning agents. The root biomodification procedure brings in definite difference between fluorosed and nonfluorosed dentin specimens. PMID:27335611

  20. Uptake of intact zinc-ethylenediaminetetraacetic acid from soil is dependent on plant species and complex concentration.

    PubMed

    Collins, Richard N; Merrington, Graham; McLaughlin, Mike J; Knudsen, Chris

    2002-09-01

    Pot experiments were conducted with barley (Hordeum vulgare L.), potato (Solanum tuberosum L.), Indian mustard (Brassicajuncea L.), and white lupin (Lupinus albus L.) to determine the nature of Zn mobilization, uptake, and root-shoot transport from a Zn-contaminated soil in the presence of increasing concentrations of ethylenediaminetetraacetic acid (EDTA; 0.0-3.4 mmole/kg soil). Increasing EDTA concentrations lead to a greater proportion of soil-solution Zn being detected as the ZnEDTA complex. However, a significant increase in the concentration of soil-solution Zn was only observed after the addition of 3.4 mmole EDTA/ kg soil. At this application rate, regardless of the plant species, 97 +/- 9% (+/- SD) of the increase in soil-solution Zn could be accounted for by chelation/desorption, and 89 +/- 9% of total Zn in solution was measured as ZnEDTA. Although the complex was detected in the xylem exudate of B. juncea after 0.34 mmole EDTA/kg soil had been added, ZnEDTA was only found in the xylem exudate of the other plant species following the highest application rate of EDTA. In this case, the accumulation of Zn and the concentration of ZnEDTA in the xylem sap of B. juncea were significantly greater than those of H. vulgare and S. tuberosum. Measurements of plant transpiration following the addition of EDTA indicated that B. juncea experienced greater physiological stress in the presence of high concentrations of EDTA. It was therefore concluded that two different mechanisms of ZnEDTA uptake existed for these plant species. Based on a review of the literature, it was hypothesized that uptake of ZnEDTA by B. juncea occurred only after physiological damage to its root system, whereas uptake by H. vulgare and S. tuberosum was via an apoplastic pathway (passive extracellular transport into the xylem).

  1. Photocatalytic oxidation of cadmium-EDTA with titanium dioxide

    SciTech Connect

    Davis, A.P.; Green, D.L.

    1999-02-15

    Ethylenediaminetetraacetic acid (EDTA) forms stable complexes with toxic metals such as cadmium. Metal-EDTA chelates are chemically stable and occur in a number of waste situations. The viability of using photocatalytic oxidation with titanium dioxide to degrade Cd-EDTA was examined at concentrations from 2 {times} 10{sup {minus}5} to 10{sup {minus}3} M at pH from 3 to 8. Initially a portion of the complex was adsorbed onto the TiO{sub 2} photocatalyst at low pH. However, independent of the degree of initial adsorption, Cd-EDTA was rapidly destroyed with little dependence on pH. Concurrently, in most cases cadmium was liberated as Cd{sup 2+} with no affiliation with organic reaction products; its fate depended on suspension pH. At low pH, Cd{sub aq}{sup 2+} was released into solution. Also, organic carbon was released into solution as oxidation of adsorbed EDTA occurred. At higher pH the Cd was adsorbed onto the TiO{sub 2} at adsorption equilibrium levels. Major products detected include formaldehyde, formic acid, and acetic acid. Nitrate and glyoxylic, malonic, and oxalic acids were detected, but concentrations were low. The incomplete carbon balance and the lack of nitrate production suggest the production of organic amines from the degradation of Cd-EDTA. Release of the Cd as Cd{sup 2+} occurs after mineralization of only about half of the organic carbon.

  2. Effect of EDTA and Tannic Acid on the Removal of Cd, Ni, Pb and Cu from Artificially Contaminated Soil by Althaea rosea Cavan.

    PubMed

    Cay, Seydahmet; Uyanik, Ahmet; Engin, Mehmet Soner; Kutbay, Hamdi Guray

    2015-01-01

    In this study an ornamental plant of Althaea rosea Cavan was investigated for its potential use in the removal of Cd, Ni, Pb and Cu from an artificially contaminated soil. Effect of two different chelating agents on the removal has also been studied by using EDTA (ethylenediaminetetracetic acid) and TA (tannic acid). Both EDTA and TA have led to higher heavy metal concentration in shoots and leaves compared to control plants. However EDTA is generally known as an effective agent in metal solubilisation of soil, in this study, TA was found more effective to induce metal accumulation in Althaea rosea Cavan under the studied conditions. In addition to this, EDTA is toxic to some species and restraining the growth of the plants. The higher BCF (Bio Concentration Factor) and TF (Translocation Factor) values obtained from stems and leaves by the effects of the chemical enhancers (EDTA and TA) show that Althaea rosea Cavan is a hyper accumulator for the studied metals and may be cultivated to clean the contaminated soils.

  3. Low concentration of ethylenediaminetetraacetic acid (EDTA) affects biofilm formation of Listeria monocytogenes by inhibiting its initial adherence.

    PubMed

    Chang, Yuhua; Gu, Weimin; McLandsborough, Lynne

    2012-02-01

    The distribution and survival of the food-borne pathogen Listeria monocytogenes is associated with its biofilm formation ability, which is affected by various environmental factors. Here we present the first evidence that EDTA at low concentration levels inhibits the biofilm formation of L. monocytogenes. This effect of EDTA is not caused by a general growth inhibition, as 0.1 mM EDTA efficiently reduced the biofilm formation of L. monocytogenes without affecting the planktonic growth. Adding 0.1 mM of EDTA at the starting time of biofilm formation had the strongest biofilm inhibitory effect, while the addition of EDTA after 8 h had no biofilm inhibitory effects. EDTA was shown to inhibit cell-to-surface interactions and cell-to-cell interactions, which at least partially contributed to the repressed initial adherence. The addition of sufficient amounts of cations to saturate EDTA did not restore the biofilm formation, indicating the biofilm inhibition was not due to the chelating properties of EDTA. The study suggests that EDTA functions in the early stage of biofilm process by affecting the initial adherence of L. monocytogenes cells onto abiotic surfaces.

  4. Analysis and environmental fate of EDTA and ETPA

    SciTech Connect

    Sillanpaeae, M.

    1997-10-24

    In this thesis, analytical techniques for the determination of two metal complexing agents, EDTA and DTPA, in aquatic environments were investigated with the main emphasis on the pulp and paper mill waste waters and the receiving natural waters. These compounds are widely used as metal chelating agents in industry. The behavior of EDTA and DTPA in waste waters and in the natural aquatic environment was investigated. In addition, the impact of EDTA and DTPA on heavy metal toxicity was studied. The thesis consists of a literature survey deals with the analytical methods developed for the determination of these aminopolycarboxylic acids. The review consists of a critical comparison of the advantages and disadvantages of chromatographic, electrochemical, spectrophotometric, titrimetric and atomic absorption methods for their applicability to the determination of EDTA and DTPA in waste and natural waters.

  5. EDTA retention and emissions from remediated soil.

    PubMed

    Jez, Erika; Lestan, Domen

    2016-05-01

    EDTA-based remediation is reaching maturity but little information is available on the state of chelant in remediated soil. EDTA soil retention was examined after extracting 20 soil samples from Pb contaminated areas in Slovenia, Austria, Czech Republic and USA with 120 mM kg(-1) Na2H2EDTA, CaNa2EDTA and H4EDTA for 2 and 24 h. On average, 73% of Pb was removed from acidic and 71% from calcareous soils (24 h extractions). On average, 15% and up to 64% of applied EDTA was after remediation retained in acidic soils. Much less; in average 1% and up to the 22% of EDTA was retained in calcareous soils. The secondary emissions of EDTA retained in selected remediated soil increased with the acidity of the media: the TCLP (Toxicity Characteristic Leaching Procedure) solution (average pH end point 3.6) released up to 36% of EDTA applied in the soil (28.1 mmol kg(-1)). Extraction with deionised water (pH > 6.0) did not produce measurable EDTA emissions. Exposing soil to model abiotic (thawing/freezing cycles) and biotic (ingestion by earthworms Lumbricus rubellus) ageing factors did not induce additional secondary emissions of EDTA retained in remediated soil. PMID:26943741

  6. Lead-enhanced gas-phase stability of multiply charged EDTA anions: a combined experimental and theoretical study.

    PubMed

    Liu, Chunxiao; Ouyang, Yongzhong; Jia, Bin; Zhu, Zhiqiang; Shi, Jianbo; Chen, Huanwen

    2012-06-01

    Besides their fundamental importance, multiply charged anions (MCAs) are considered as promising molecular capacitors for which their intrinsic stabilities are of great significance. Herein, the gas-phase stabilities of ethylenediaminetetraacetic acid (EDTA) anions (i.e. [EDTA-nH](n-), n = 1-4) and their Pb(II) complexes (i.e. [EDTA + Pb-nH]((2-n)-), n = 3, 4) have been investigated using an approach that combines extractive electrospray ionization mass spectrometry (EESI-MS) measurements, Car-Parrinello molecular dynamics simulations and density functional theory/Tao-Perdew-Staroverov-Scuseria calculations. The EESI-MS data showed that the doubly charged EDTA anions in the form of [EDTA-2H](2-) and [EDTA + Pb-4H](2-) were much more abundantly observed than the singly charged species such as [EDTA-H](-) and [EDTA + Pb-3H](-), respectively. The calculation results indicated that [EDTA-2H](2-) and [EDTA + Pb-4H](2-) anions were thermodynamically more stable than the [EDTA-H](-) and [EDTA + Pb-3H](-) species in the gas phase, respectively. The [EDTA + Pb-3H](-) anions preferred five-coordinated structure, whereas [EDTA + Pb-4H](2-) anions formed either five-coordinated or six-coordinated structures. The calculations further revealed that significant electron clouds drifting from the ligand EDTA to the metal Pb(II) ions and the large distances between the carboxylic groups reduced the Coulomb repulsion among the excess electrons of these MCAs. Our data demonstrated that EESI-MS combined with theoretic calculations were able to provide a deep insight into the fundamental behavior of stability of MCAs in the gas phase and, thus, might be useful tools for studying MCAs for potential molecular capacitors.

  7. Effects of nisin, EDTA and salts of organic acids on Listeria monocytogenes, Salmonella and native microflora on fresh vacuum packaged shrimps stored at 4 °C.

    PubMed

    Wan Norhana, M N; Poole, Susan E; Deeth, Hilton C; Dykes, Gary A

    2012-08-01

    Nisin (500 IU ml⁻¹), EDTA (0.02 M), potassium sorbate (PS) (3%, w/v), sodium benzoate (SB) (3%, w/v) or sodium diacetate (SD) (3%, w/v); alone or in combination were used to dip uninoculated shrimps and shrimps inoculated with Listeria monocytogenes or Salmonella (∼4.0-5.0 log CFU g⁻¹). Shrimps were then drip-dried, vacuum packaged and stored at 4 °C for 7 days. Untreated shrimps were used as a control. Numbers of L. monocytogenes, Salmonella and native background microflora were determined on uninoculated and inoculated shrimps on days 0, 3 and 7. Nisin-EDTA-PS and nisin-EDTA-SD significantly reduced (p < 0.05) L. monocytogenes numbers by 1.07-1.27 and 1.32-1.36 log CFU g⁻¹, respectively, on day 0 and 3. However, all treatments failed to significantly reduce (p > 0.05) Salmonella counts on shrimps throughout storage. On day 7, numbers of aerobic bacteria, psychrotrophic bacteria and Pseudomonas on combined nisin-EDTA-salt of organic acids treated shrimps were significantly lower (p < 0.05) by 4.40-4.60, 3.50-4.01, and 3.84-3.99 log CFU g⁻¹ respectively, as compared to the control. Dipping in organic acids solutions followed by vacuum packaging and chilled storage can help reduce L. monocytogenes and native microflora, but not Salmonella, on fresh shrimps. PMID:22475941

  8. Coordination Modes in the Formation of Ternary Complexes of Am(III), Cm(III) and Eu(III) with EDTA and NTA: TRLFS, 13C NMR, EXAFS, and Thermodynamics of the complexation.

    SciTech Connect

    Mathur,J.; Thakur, P.; Dodge, C.; Francis, A.; Choppin, G.

    2006-01-01

    The formation and the structure of the ternary complexes of trivalent Am, Cm, and Eu with mixtures of EDTA+NTA (ethylenediamine tetraacetate and nitrilotriacetate) have been studied by time-resolved laser fluorescence spectroscopy, {sup 13}C NMR, extended X-ray absorption fine structure, and two-phase metal ion equilibrium distribution at 6.60 m (NaClO{sub 4}) and a hydrogen ion concentration value (pcH) between 3.60 and 11.50. In the ternary complexes, EDTA binds via four carboxylates and two nitrogens, while the binding of the NTA varies with the hydrogen ion concentration, pcH, and the concentration ratios of the metal ion and the ligand. When the concentration ratios of the metal to ligand is low (1:1:1-1:1:2), two ternary complexes, M(EDTA)(NTAH){sup 3-} and M(EDTA)(NTA){sup 4-}, are formed at pcH ca. 9.00 in which NTA binds via three carboxylates, via two carboxylates and one nitrogen, or via two carboxylates and a H{sub 2}O. At higher ratios (1:1:20 and 1:10:10) and pcH's of ca. 9.00 and 11.50, one ternary complex, M(EDTA)(NTA){sup 4-}, is formed in which NTA binds via three carboxylates and not via nitrogen. The two-phase equilibrium distribution studies at tracer concentrations of Am, Cm, and Eu have also confirmed the formation of the ternary complex M(EDTA)(NTA){sup 4-} at temperatures between 0 and 60 {sup o}C. The stability constants (log{beta}{sub 111}) for these metal ions increase with increasing temperature. The endothermic enthalpy and positive entropy indicated a significant effect of cation dehydration in the formation of the ternary complexes at high ionic strength.

  9. The Ability of PAS, Acetylsalicylic Acid and Calcium Disodium EDTA to Protect Against the Toxic Effects of Manganese on Mitochondrial Respiration in Gill of Crassostrea virginica.

    PubMed

    Crawford, Sherine; Davis, Kiyya; Saddler, Claudette; Joseph, Jevaun; Catapane, Edward J; Carroll, Margaret A

    2011-01-01

    Manganese (Mn) is an essential metal that at excessive levels in brain causes Manganism, a condition similar to Parkinson's disease. Previously we showed that Mn had a neurotoxic effect on the dopaminergic, but not serotonergic, innervation of the lateral ciliated cells in the gill of the Eastern Oyster, Crassostrea virginica. While the mechanism of action of Mn toxicity is not completely understood, studies suggest that Mn toxicity may involve mitochondrial damage and resulting neural dysfunction in the brain's dopaminergic system. In this study we utilized micro-batch chambers and oxygen probes to measure oyster gill mitochondrial respiration in the presence of Mn and potential Mn blockers. The addition of Mn to respiring mitochondria caused a dose dependent decrease in mitochondrial O(2) consumption. Pretreating mitochondria with calcium disodium EDTA (caEDTA), p aminosalicylic acid (PAS) or acetylsalicylic acid (ASA) before Mn additions, provided full protection against the toxic effects of Mn. While mitochondrial pretreatment with any of the 3 drugs effectively blocked Mn toxicity, none of the drugs tested was able to reverse the decrease in mitochondrial O(2) consumption seen in Mn treated mitochondria. The study found that high levels of Mn had a toxic effect on gill mitochondrial O(2) consumption and that this effect could be blocked by the drugs caEDTA, PAS and ASA. C. virginica continues to be a good model with which to investigate the mechanism that underlies manganese neurotoxcity and in the pharmacological study of drugs to treat or prevent Manganism. PMID:21977482

  10. The Ability of PAS, Acetylsalicylic Acid and Calcium Disodium EDTA to Protect Against the Toxic Effects of Manganese on Mitochondrial Respiration in Gill of Crassostrea virginica

    PubMed Central

    Crawford, Sherine; Davis, Kiyya; Saddler, Claudette; Joseph, Jevaun; Catapane, Edward J.; Carroll, Margaret A.

    2011-01-01

    Manganese (Mn) is an essential metal that at excessive levels in brain causes Manganism, a condition similar to Parkinson's disease. Previously we showed that Mn had a neurotoxic effect on the dopaminergic, but not serotonergic, innervation of the lateral ciliated cells in the gill of the Eastern Oyster, Crassostrea virginica. While the mechanism of action of Mn toxicity is not completely understood, studies suggest that Mn toxicity may involve mitochondrial damage and resulting neural dysfunction in the brain’s dopaminergic system. In this study we utilized micro-batch chambers and oxygen probes to measure oyster gill mitochondrial respiration in the presence of Mn and potential Mn blockers. The addition of Mn to respiring mitochondria caused a dose dependent decrease in mitochondrial O2 consumption. Pretreating mitochondria with calcium disodium EDTA (caEDTA), p aminosalicylic acid (PAS) or acetylsalicylic acid (ASA) before Mn additions, provided full protection against the toxic effects of Mn. While mitochondrial pretreatment with any of the 3 drugs effectively blocked Mn toxicity, none of the drugs tested was able to reverse the decrease in mitochondrial O2 consumption seen in Mn treated mitochondria. The study found that high levels of Mn had a toxic effect on gill mitochondrial O2 consumption and that this effect could be blocked by the drugs caEDTA, PAS and ASA. C. virginica continues to be a good model with which to investigate the mechanism that underlies manganese neurotoxcity and in the pharmacological study of drugs to treat or prevent Manganism. PMID:21977482

  11. Growth and spectral characterization of ethylene diamine tetra acetic acid (EDTA) doped zinc sulphate hepta hydrate - a semi organic NLO material.

    PubMed

    Ramachandra Raja, C; Ramamurthi, K; Manimekalai, R

    2012-12-01

    Semi-organic non-linear optical single crystals of ethylene diamine tetra acetic acid (EDTA) doped zinc sulphate hepta hydrate crystals were grown by slow evaporation solution growth technique, at room temperature, using de-ionized water as solvent. The modes of vibrations of different molecular groups present in the grown crystal were identified by FT-IR technique. The optical absorbance/transmittance was recorded in the wavelength range of 190-1100 nm. Thermal properties of the grown crystal were studied by thermo gravimetric analysis and differential thermal analysis. The melting point of the grown crystal was estimated by differential scanning calorimetric analysis. The inclusion of the dopant (EDTA) was confirmed by colorimetric estimation method. The second harmonic generation efficiency is about 30% of potassium dihydrogen orthophosphate.

  12. Biodegradation of PuEDTA and Impacts on Pu Mobility

    SciTech Connect

    Xun, Luying; Bolton, Jr., Harvey

    2001-06-01

    Ethylenediaminetetraacetate (EDTA) and nitrilotriacetate (NTA) are synthetic chelating agents, which can form strong water-soluble complexes with radionuclides and metals and has been used to decontaminate and process nuclear materials. Synthetic chelating agents were co-disposed with radionuclides (e.g., 60Co, Pu) and heavy metals enhancing their transport in the subsurface. An understanding of EDTA biodegradation is essential to help mitigate enhanced radionuclide transport by EDTA. The objective of this research is to develop fundamental data on factors that govern the biodegradation of radionuclide-EDTA. These factors include the dominant EDTA aqueous species, the biodegradation of various metal-EDTA complexes, the uptake of various metal-EDTA complexes into the cell, the distribution and mobility of the radionuclide during and after EDTA biodegradation, and the enzymology and genetics of EDTA biodegradation.

  13. Bis(methylpyridine)-EDTA derivative as a potential ligand for PET imaging: synthesis, complexation, and biological evaluation.

    PubMed

    Singh, Pooja; Aggarwal, Swati; Tiwari, Anjani K; Kumar, Vikas; Pratap, Ramendra; Chuttani, Krishna; Mishra, Anil K

    2014-12-01

    A novel transitional metal ligand derivatized from EDTA-conjugated 2-amino-4-methyl pyridine, an acyclic vehicle (EDTA-Mepy2 ) was designed, synthesized, and characterized for PET imaging with ⁶⁸Ga. The drug likeliness and appropriate lipophilicity were first analyzed by molecular docking studies which shows interactive property of ligand with serum albumin protein (HSA: PDB 1E78), at Lys199, Arg257, and His242 residues, which make it more appropriate in transportation as a specific ligand for PET imaging. As a confirmation, binding constant of the ligand with human serum albumin was calculated at λex = 350 nm which was found to be 4.9 × 10³ m⁻¹. The pharmacokinetics of (68) Ga-EDTA-Mepy2 was analyzed by blood kinetics (t(1/2) slow: 3 h 56 min and t(1/2) fast: 32 min) and biodistribution (maximum % ID/g was found in kidney at 1 h). Further the capability of this ligand was analyzed as optical marker also, by recording λex = 380 nm, RFU = 8000; 710 nm, RFU = 1000 units at fixed λem = 280 nm. Additionally, in physiological conditions where its stability was calculated, suggests 15-20 times selectivity over the endogenously present metal ions (KG aL /KZ nL = 14.3, KG aL /KC uL = 18.1).

  14. Competitive adsorption of Cu(II)-EDTA and Cd(II)-EDTA onto TiO{sub 2}

    SciTech Connect

    Yang, J.K.; Davis, A.P.

    1999-08-01

    Cu(II), EDTA, Cu(II)-EDTA, Cd(II)-EDTA, and Cu(II)/Cd(II) and Cu(II)-EDTA/Cd(II)-EDTA competitive adsorption onto TiO{sub 2} has been studied with variation of pH and concentration. For Cu(II) and EDTA, typical cationic and anionic types of adsorption are noted, respectively. Ligand-type adsorption is found for Cu(II)-EDTA and Cd(II)-EDTA under both single and competitive conditions. Surface complexation modeling considered inner-sphere complexation and the diffuse layer model employing MINTEQA2; surface complexes used include Ti-(OH{sub 2})O-Cu{sup +}, Ti-(OH)EDTAH{sub 2}{sup {minus}2}, Ti-(OH)EDTA-Cu{sup {minus}2}, and Ti-(OH)EDTA-Cd{sup {minus}2}. Experimental and model predictions suggest no competitive adsorption between Cu(II) and Cd(II) at 5 {times} 10{sup {minus}5} M. On the other hand, adsorption data and model predictions indicate that Cd(II)-EDTA adsorption is favored over that of Cu(II)-EDTA with some competition for adsorption sites. Cd(II)-EDTA Adsorption was only slightly affected by the presence of Cu(II)-EDTA; however, Cu(II)-EDTA adsorption was strongly influenced by the presence of Cd(II)-EDTA, especially as the molar ratio of Cd(II)-EDTA/Cu(II)-EDTA increased. A modified surface complexation constant for Cd(II)-EDTA is required to explain the competitive data, suggesting surface site heterogeneity.

  15. EDTA-dependent pseudothrombocytopenia in a child.

    PubMed

    Akbayram, Sinan; Dogan, Murat; Akgun, Cihangir; Caksen, Hüseyin; Oner, Ahmet Faik

    2011-10-01

    Ethylenediaminetetraacetic acid (EDTA)-dependent pseudothrombocytopenia (PTCP) is the phenomenon of a spurious low platelet count due to antiplatelet antibodies that cause platelet clumping in blood anticoagulated with EDTA. The aggregation of platelets in EDTA-dependent PTCP is usually prevented by other anticoagulants, such as sodium citrate or heparin. EDTA-dependent PTCP has never been associated with hemorrhagic diathesis or platelet dysfunction. In this article, a 10-year-old boy with EDTA- and heparin-dependent PTCP is presented because of rare presentation. We report that EDTA and heparin can induce platelet clumping, and thus spuriously low platelet counts. However, aggregation of platelets was not detected in blood samples with sodium citrate, and platelet count was normal. PMID:20530050

  16. The implementation of high fermentative 2,3-butanediol production from xylose by simultaneous additions of yeast extract, Na2EDTA, and acetic acid.

    PubMed

    Wang, Xiao-Xiong; Hu, Hong-Ying; Liu, De-Hua; Song, Yuan-Quan

    2016-01-25

    The effective use of xylose may significantly enhance the feasibility of using lignocellulosic hydrolysate to produce 2,3-butanediol (2,3-BD). Previous difficulties in 2,3-BD production include that the high-concentration xylose cannot be converted completely and the fermentation rate is slow. This study investigated the effects of yeast extract, ethylenediaminetetraacetic acid disodium salt (Na2EDTA), and acetic acid on 2,3-BD production from xylose. The central composite design approach was used to optimize the concentrations of these components. It was found that simultaneous addition of yeast extract, Na2EDTA, and acetic acid could significantly improve 2,3-BD production. The optimal concentrations of yeast extract, Na2EDTA, and acetic acid were 35.2, 1.2, and 4.5 g/L, respectively. The 2,3-BD concentration in the optimized medium reached 39.7 g/L after 48 hours of shake flask fermentation, the highest value ever reported in such a short period. The xylose utilization ratio and the 2,3-BD concentration increased to 99.0% and 42.7 g/L, respectively, after 48 hours of stirred batch fermentation. Furthermore, the 2,3-BD yield was 0.475 g/g, 95.0% of the theoretical maximum value. As the major components of lignocellulosic hydrolysate are glucose, xylose, and acetic acid, the results of this study indicate the possibility of directly using the hydrolysate to effectively produce 2,3-BD.

  17. Removal of arsenic and cadmium with sequential soil washing techniques using Na2EDTA, oxalic and phosphoric acid: Optimization conditions, removal effectiveness and ecological risks.

    PubMed

    Wei, Meng; Chen, Jiajun; Wang, Xingwei

    2016-08-01

    Testing of sequential soil washing in triplicate using typical chelating agent (Na2EDTA), organic acid (oxalic acid) and inorganic weak acid (phosphoric acid) was conducted to remediate soil contaminated by heavy metals close to a mining area. The aim of the testing was to improve removal efficiency and reduce mobility of heavy metals. The sequential extraction procedure and further speciation analysis of heavy metals demonstrated that the primary components of arsenic and cadmium in the soil were residual As (O-As) and exchangeable fraction, which accounted for 60% and 70% of total arsenic and cadmium, respectively. It was determined that soil washing agents and their washing order were critical to removal efficiencies of metal fractions, metal bioavailability and potential mobility due to different levels of dissolution of residual fractions and inter-transformation of metal fractions. The optimal soil washing option for arsenic and cadmium was identified as phosphoric-oxalic acid-Na2EDTA sequence (POE) based on the high removal efficiency (41.9% for arsenic and 89.6% for cadmium) and the minimal harmful effects of the mobility and bioavailability of the remaining heavy metals.

  18. Removal of arsenic and cadmium with sequential soil washing techniques using Na2EDTA, oxalic and phosphoric acid: Optimization conditions, removal effectiveness and ecological risks.

    PubMed

    Wei, Meng; Chen, Jiajun; Wang, Xingwei

    2016-08-01

    Testing of sequential soil washing in triplicate using typical chelating agent (Na2EDTA), organic acid (oxalic acid) and inorganic weak acid (phosphoric acid) was conducted to remediate soil contaminated by heavy metals close to a mining area. The aim of the testing was to improve removal efficiency and reduce mobility of heavy metals. The sequential extraction procedure and further speciation analysis of heavy metals demonstrated that the primary components of arsenic and cadmium in the soil were residual As (O-As) and exchangeable fraction, which accounted for 60% and 70% of total arsenic and cadmium, respectively. It was determined that soil washing agents and their washing order were critical to removal efficiencies of metal fractions, metal bioavailability and potential mobility due to different levels of dissolution of residual fractions and inter-transformation of metal fractions. The optimal soil washing option for arsenic and cadmium was identified as phosphoric-oxalic acid-Na2EDTA sequence (POE) based on the high removal efficiency (41.9% for arsenic and 89.6% for cadmium) and the minimal harmful effects of the mobility and bioavailability of the remaining heavy metals. PMID:27179243

  19. EDTA disodium zinc has superior bioavailability compared to common inorganic or chelated zinc compounds in rats fed a high phytic acid diet.

    PubMed

    Bertinato, Jesse; Sherrard, Lindsey; Plouffe, Louise J

    2012-10-01

    Different zinc (Zn) compounds have unique properties that may influence the amount of Zn absorbed particularly in the presence of phytic acid (PA), a common food component that binds Zn and decreases its bioavailability. In this study, 30-day-old male rats (n=12/diet group) were fed diets supplemented with PA (0.8%) and low levels (8mg Zn/kg diet) of inorganic (Zn oxide, Zn sulphate) or chelated (Zn gluconate, Zn acetate, Zn citrate, EDTA disodium Zn, Zn orotate) Zn compounds for 5 weeks. Two control groups were fed diets supplemented with low or normal (30mg Zn/kg diet) Zn (as Zn oxide) without added PA. Control rats fed the low Zn oxide diet showed depressed Zn status. Addition of PA to this diet exacerbated the Zn deficiency in rats. Growth (body weight gain and femur length) and Zn concentrations in plasma and tissues were similar in rats fed Zn oxide, Zn sulphate, Zn gluconate, Zn acetate, Zn citrate or Zn orotate. Rats fed EDTA disodium Zn showed enhanced growth compared to rats fed Zn oxide or Zn gluconate and had higher Zn concentrations in plasma and femur compared to rats fed all other Zn compounds. Only the haematological profile of rats fed EDTA disodium Zn did not differ from control rats fed normal Zn. These data indicate that in rats fed a high PA diet, bioavailability of commonly used inorganic or chelated Zn compounds does not differ appreciably, but Zn supplied as an EDTA disodium salt has superior bioavailability.

  20. Photodynamic therapy of human skin tumors using topical application of 5-aminolevulinic acid, dimethylsulfoxide (DMSO), and edetic acid disodium salt (EDTA)

    NASA Astrophysics Data System (ADS)

    Orenstein, Arie; Kostenich, Gennady; Tsur, H.; Roitman, Leonid; Ehrenberg, Benjamin; Malik, Zvi

    1995-01-01

    The results of photodynamic therapy (PDT) in 48 patients bearing basal cell carcinoma (BCC) and 7 patients with squamous cell carcinoma (SCC) of the skin are described. Five- aminolevulinic acid (5-ALA) was applied topically in two formulations. The first formulation contained 20% of 5-ALA in a base cream, and the second formulation (5-ALA composite cream), contained an additional 2% of dimethylsulfoxide (DMSO) and 2% of edetic acid disodium salt (EDTA). The creams were left on the skin for 2 - 5 hours. Production of protoporphyrin (PP) was measured in situ by a laser-induced fluorescence (LIF) method. The results of fluorescence measurement clearly indicate that PP accumulation in tumors induced by the 5-ALA composite cream was markedly higher than that induced by the 5-ALA cream. The tumors were light-irradiated (600 - 720 nm) after 4 - 5 hours of cream applications, using the light delivery system Versa-Light by a light dose of 100 J/cm2. The clinically superficial BCC tumors were highly responsive to PDT; the overall result in BCC patients was an 85.4% complete response. Histological examination showed an initial edematous reaction, followed by necrosis and complete disappearance of the tumor. The superficial SCC tumors showed a 100% complete response after PDT. The ulcerated nodular SCC showed partial responses.

  1. Fe(III)EDTA and Fe(II)EDTA-NO reduction by a sulfate reducing bacterium in NO and SO₂ scrubbing liquor.

    PubMed

    Chen, Mingxiang; Zhou, Jiti; Zhang, Yu; Wang, Xiaojun; Shi, Zhuang; Wang, Xiaowei

    2015-03-01

    A viable process concept, based on NO and SO2 absorption into an alkaline Fe(II)EDTA (EDTA: ethylenediaminetetraacetic acid) solution in a scrubber combined with biological reduction of the absorbed SO2 utilizing sulfate reducing bacteria (SRB) and regeneration of the scrubbing liquor in a single bioreactor, was developed. The SRB, Desulfovibrio sp. CMX, was used and its sulfate reduction performances in FeEDTA solutions and Fe(II)EDTA-NO had been investigated. In this study, the detailed regeneration process of Fe(II)EDTA solution, which contained Fe(III)EDTA and Fe(II)EDTA-NO reduction processes in presence of D. sp. CMX and sulfate, was evaluated. Fe(III)EDTA and Fe(II)EDTA-NO reduction processes were primarily biological, even if Fe(III)EDTA and Fe(II)EDTA-NO could also be chemically convert to Fe(II)EDTA by biogenic sulfide. Regardless presence or absence of sulfate, more than 87 % Fe(III)EDTA and 98 % Fe(II)EDTA-NO were reduced in 46 h, respectively. Sulfate and Fe(III)EDTA had no affection on Fe(II)EDTA-NO reduction. Sulfate enhanced final Fe(III)EDTA reduction. Effect of Fe(III)EDTA on Fe(II)EDTA-NO reduction rate was more obvious than effect of sulfate on Fe(II)EDTA-NO reduction rate before 8 h. To overcome toxicity of Fe(II)EDTA-NO on SRB, Fe(II)EDTA-NO was reduced first and the reduction of Fe(III)EDTA and sulfate occurred after 2 h. First-order Fe(II)EDTA-NO reduction rate and zero-order Fe(III)EDTA reduction rate were detected respectively before 8 h.

  2. Treatment of waste containing EDTA by chemical oxidation

    SciTech Connect

    Tucker, M.D.; Barton, L.L.; Thomson, B.M.; Wagener, B.M.; Aragon, A.

    1999-07-01

    Ethylenediaminetetraacetic acid (EDTA) is a chelating agent that has been extensively used to enhance the solubilization of heavy metal cations and release of EDTA contributes to environmental problems. EDTA is recalcitrant to microbial metabolism and chemical oxidation is considered a possible method of remedial treatment. The use of the commercially available process of MIOX Corporation generates mixed oxidants on site and this solution is markedly effective in the destruction of the chelating characteristic and the decarboxylation of EDTA. When measuring the release of C-14 from carboxyl labeled EDTA, the mixed oxidant solution was comparable to the Fenton's reaction over a broad pH range. The presence of Mn{sup 2+}, Cr{sup 3+}, or Fe{sup 3+} at levels equal to that of EDTA stimulated the rate of EDTA decomposition; however, the rate of EDTA breakdown was inhibited when the concentration of Cr{sup 3+} or Mn{sup 2+} exceeded the concentration of EDTA. The treatment of Co{sup 2+} -EDTA or Cu{sup 2+} -EDTA with mixed oxidants in the presence of ultra violet light resulted in the loss of chelation ability of EDTA. In the absence of chelated metals, over 75% of the chelation property of a 70 nM EDTA solution was destroyed in 45 min. The reaction products resulting from the use of mixed oxidants added to EDTA were non-toxic to bacteria and should not contribute to additional environmental problems.

  3. Biodegradation of novel amino acid derivatives suitable for complexing agents in pulp bleaching applications.

    PubMed

    Metsärinne, Sirpa; Ronkainen, Erja; Tuhkanen, Tuula; Aksela, Reijo; Sillanpää, Mika

    2007-05-01

    The biodegradability of four novel diethanolamine derivative complexing agents was examined by using two biodegradation tests standardised by OECD (301B and 301F). Ethylenediaminetetraacetic acid (EDTA) and diethylenetriaminepentaacetic acid (DTPA) were employed as reference substances. Biodegradation of the new complexing agents was studied both with unacclimated and acclimated inocula as well as by simulating wastewater treatment in sequencing batch reactors (SBRs). These new complexing agents were of technical grade, and therefore, the results are only indicative but these new compounds hold promise for use as complexing agents in the pulp and paper industry. The novel complexing agents were not readily biodegradable but they showed slight biodegradation. Around 10-30% degradation was found in the SBR where degradation was followed by measurement of concentration. Moreover the novel complexing agents did not have any negative impact on reactor performance as measured by chemical oxygen demand reduction. In the standardised biodegradation tests at best around 50% degradation was observed with the acclimated inoculum and in the prolonged test whereas EDTA and DTPA exhibited no biodegradation. The elevated degradation in acclimated sludge indicates that the water treatment plant microbes are capable of decomposing these molecules under favourable conditions. The total concentration of novel complexing agents decreased slightly during biodegradation tests, while the EDTA and DTPA concentrations remained stable. PMID:17346781

  4. Complexing of amino acids to DNA by chromate in intact cells.

    PubMed Central

    Voitkun, V; Zhitkovich, A; Costa, M

    1994-01-01

    Using o-pthaldialdehyde (OPT) fluorescence, the amino acids associated with DNA were studied following exposure of intact Chinese hamster ovary cells to chromate. Rigorous extraction with EDTA, acid, or base was required to release the amino acids cross-linked to the DNA isolated from control or chromate-treated cells by standard procedures (i.e., proteinase K, phenol, etc.). Amino acids resisting extraction from DNA were not studied since analysis was limited to those that could be released by these procedures. There was a chromate dose-dependent increase in amino acids complexed with the DNA that could be released by EDTA, acid, and base, and these amino acids were separated by HPLC and identified. Substantial increases in cysteine, glutamine, glutamic acid, histidine, threonine, and tyrosine were found as a function of increasing concentrations of chromate. There was also a time-dependent increase in complexing of these amino acids to the DNA by chromate. The amino acids found complexed to DNA in intact cells by chromate were thought to originate from reactions of free amino acids or small peptides with the DNA rather than being proteolytic products derived from larger proteins that were cross-linked to the DNA. This was supported by a number of experiments: a) free amino acids or bovine serum albumin (BSA) were cross-linked by chromium to DNA in vitro and the DNA was isolated by standard procedures.(ABSTRACT TRUNCATED AT 250 WORDS) PMID:7843108

  5. Biodegradation of PuEDTA and Impacts on Pu Mobility

    SciTech Connect

    Bolton, H., Jr.; Rai, D.; Xun, L.

    2004-03-17

    The contamination of many DOE sites by Pu presents a long-term problem because of its long half-life (240,000 yrs) and the low drinking water standard (<10{sup -12} M). EDTA was co-disposed with radionuclides (e.g., Pu, {sup 60}Co), formed strong complexes, and enhanced radionuclide transport at several DOE sites. Biodegradation of EDTA should decrease Pu mobility. One objective of this project was to determine the biodegradation of EDTA in the presence of PuEDTA complexes. The aqueous system investigated at pH 7 (10{sup -4} M EDTA and 10{sup -6} M Pu) contained predominantly Pu(OH){sub 2}EDTA{sup 2-}. The EDTA was degraded at a faster rate in the presence of Pu. As the total concentration of both EDTA and PuEDTA decreased (i.e., 10{sup -5} M EDTA and 10{sup -7} M PuEDTA), the presence of Pu decreased the biodegradation rate of the EDTA. It is currently unclear why the concentration of Pu directly affects the increase/decrease in rate of EDTA biodegradation. The soluble Pu concentration decreased, in agreement with thermodynamic predictions, as the EDTA was biodegraded, indicating that biodegradation of EDTA will decrease Pu mobility when the Pu is initially present as Pu(IV)EDTA. A second objective was to investigate how the presence of competing metals, commonly encountered in geologic media, will influence the speciation and biodegradation of Pu(IV)-EDTA. Studies on the solubilities of Fe(OH){sub 3}(s) and of Fe(OH){sub 3}(s) plus PuO{sub 2}(am) in the presence of EDTA and as a function of pH showed that Fe(III) out competes the Pu(IV) for the EDTA complex, thereby showing that Pu(IV) will not form stable complexes with EDTA for enhanced transport of Pu in Fe(III) dominated subsurface systems. A third objective is to investigate the genes and enzymes involved in EDTA biodegradation. BNC1 can use EDTA and another synthetic chelating agent nitrilotriacetate (NTA) as sole carbon and nitrogen sources. The same catabolic enzymes are responsible for both EDTA and NTA

  6. Adsorption of Pb(II), EDTA, and Pb(II)-EDTA onto TiO{sub 2}

    SciTech Connect

    Vohra, M.S.; Davis, A.P.

    1998-02-01

    The adsorption of aqueous Pb(II), EDTA, and Pb(II)-EDTA complexes onto TiO{sub 2} were studied at both stoichiometric and non-stoichiometric Pb(II)/EDTA concentrations. For Pb(II)-TiO{sub 2} and ECTA-TiO{sub 2}, a typical cationic and anionic-type of adsorption was noted, respectively. For 10{sup {minus}3} and 10{sup {minus}4} M Pb(II)-EDTA systems, near-equal adsorption of Pb(II) and EDTA indicated that the complex adsorbs as a single species. Also, a ligand-type Pb(II)-EDTA adsorption, i.e., decreasing adsorption with an increase in the pH, was noted. Systems with EDTA greater than Pb(II) showed near-zero lead removal; competitive adsorption of EDTA and Pb(II)-EDTA onto TiO{sub 2} was suggested to cause this effect. For Pb(II) concentrations (5 {times} 10{sup {minus}4} and 10{sup {minus}3} M) higher than EDTA (10{sup {minus}4} M), significantly higher EDTA adsorption at high pH as compared to individual 10{sup {minus}4} EDTA and 10{sup {minus}4} M Pb(II)-EDTA systems was noted. Adsorption modeling was completed employing the geochemical speciation model MINTEQA2 employing the diffuse layer model. Inner-sphere complexation was considered to occur between Pb(II), EDTA, Pb(II)-EDTA, and the TiO{sub 2} surface sites. Surface complexes used in the modeling included Ti-O-Pb{sup +}, Ti-EDTAH{sup 2{minus}}, Ti-EDTA-Pb{sup {minus}}, and Ti-O-Pb-EDTA{sup 3{minus}}. The cationic-type complexation, Ti-O-Pb-EDTA{sup 3{minus}}, was postulated to explain and model the anomalous EDTA adsorption as noted for Pb(II) > EDTA studies. Results from the present study show that the adsorption behavior in aqueous metal/EDTA systems will change with any variation in the contaminant concentration ratios.

  7. Radical generating coordination complexes as tools for rapid and effective fragmentation and fluorescent labeling of nucleic acids for microchip hybridization.

    SciTech Connect

    Kelly, J. J.; Chernov, B. N.; Mirzabekov, A. D.; Bavykin, S. G.; Biochip Technology Center; Northwestern Univ.; Engelhardt Inst. of Molecular Biology

    2002-01-01

    DNA microchip technology is a rapid, high-throughput method for nucleic acid hybridization reactions. This technology requires random fragmentation and fluorescent labeling of target nucleic acids prior to hybridization. Radical-generating coordination complexes, such as 1,10-phenanthroline-Cu(II) (OP-Cu) and Fe(II)-EDTA (Fe-EDTA), have been commonly used as sequence nonspecific 'chemical nucleases' to introduce single-strand breaks in nucleic acids. Here we describe a new method based on these radical-generating complexes for random fragmentation and labeling of both single- and double-stranded forms of RNA and DNA. Nucleic acids labeled with the OP-Cu and the Fe-EDTA protocols revealed high hybridization specificity in hybridization with DNA microchips containing oligonucleotide probes selected for identification of 16S rRNA sequences of the Bacillus group microorganisms.We also demonstrated cDNA- and cRNA-labeling and fragmentation with this method. Both the OP-Cu and Fe-EDTA fragmentation and labeling procedures are quick and inexpensive compared to other commonly used methods. A column-based version of the described method does not require centrifugation and therefore is promising for the automation of sample preparations in DNA microchip technology as well as in other nucleic acid hybridization studies.

  8. Anaerobic Biotransformation and Mobility of Pu and Pu-EDTA

    SciTech Connect

    Bolton, H., Jr.; Rai, D.; Xun, L.

    2005-04-18

    The complexation of radionuclides (e.g., plutonium (Pu) and {sup 60}Co) by codisposed ethylenediaminetetraacetate (EDTA) has enhanced their transport in sediments at DOE sites. Our previous NABIR research investigated the aerobic biodegradation and biogeochemistry of Pu(IV)-EDTA. Plutonium(IV) forms stable complexes with EDTA under aerobic conditions and an aerobic EDTA degrading bacterium can degrade EDTA in the presence of Pu and decrease Pu mobility. However, our recent studies indicate that while Pu(IV)-EDTA is stable in simple aqueous systems, it is not stable in the presence of relatively soluble Fe(III) compounds (i.e., Fe(OH){sub 3}(s)--2-line ferrihydrite). Since most DOE sites have Fe(III) containing sediments, Pu(IV) in likely not the mobile form of Pu-EDTA in groundwater. The only other Pu-EDTA complex stable in groundwater relevant to DOE sites would be Pu(III)-EDTA, which only forms under anaerobic conditions. Research is therefore needed in this brand new project to investigate the biotransformation of Pu and Pu-EDTA under anaerobic conditions. The biotransformation of Pu and Pu-EDTA under various anaerobic regimes is poorly understood including the reduction kinetics of Pu(IV) to Pu(III) from soluble (Pu(IV)-EDTA) and insoluble Pu(IV) as PuO2(am) by metal reducing bacteria, the redox conditions required for this reduction, the strength of the Pu(III)-EDTA complex, how the Pu(III)-EDTA complex competes with other dominant anoxic soluble metals (e.g., Fe(II)), and the oxidation kinetics of Pu(III)-EDTA. Finally, the formation of a stable soluble Pu(III)-EDTA complex under anaerobic conditions would require degradation of the EDTA complex to limit Pu(III) transport in geologic environments. Anaerobic EDTA degrading microorganisms have not been isolated. These knowledge gaps preclude the development of a mechanistic understanding of how anaerobic conditions will influence Pu and Pu-EDTA fate and transport to assess, model, and design approaches to stop

  9. Detection of nucleotide- and F-actin-induced movements in the switch II helix of the skeletal myosin using its differential oxidative cleavage mediated by an iron-EDTA complex disulfide-linked to the strong actin binding site.

    PubMed

    Bertrand, R; Capony, J P; Derancourt, J; Kassab, R

    1999-09-14

    We have synthesized the mixed disulfide, S-(2-nitro-5-thiobenzoic acid) cysteaminyl-EDTA, using a rapid procedure and water-soluble chemistry. Its disulfide-thiol exchange reaction with rabbit myosin subfragment-1 (S-1), analyzed by spectrophotometry, ATPase assays, and peptide mapping, led to the incorporation of the cysteaminyl-EDTA group into only Cys 540 on the heavy chain and into the unique cysteine on the alkali light chains. The former thiol, residing in the strong actin binding site, reacted at a much faster rate with a concomitant 3-fold decrease in the V(max) for acto-S-1 ATPase but without change in the essential enzymatic functions of S-1. Upon chelation of Fe(3+) ions to the Cys 540-bound EDTA and incubation of the S-1 derivative-Fe complex with ascorbic acid at pH 7.5, the 95 kDa heavy chain underwent a conformation-dependent, single-cut oxidative fragmentation within 5-15 A of Cys 540. Three pairs of fragments were formed which, after specific fluorescent labeling and SDS-PAGE, could be positioned along the heavy chain sequence as 68 kDa-26 kDa, 62 kDa-32 kDa, and 54 kDa-40 kDa. Densitometric measurements revealed that the yield of the 54 kDa-40 kDa pair of bands, but not that for the two other pairs, was very sensitive to S-1 binding to nucleotides or phosphate analogues as well as to F-actin. In binary complexes, all the former ligands specifically lowered the yield to 40% of S-1 alone, roughly in the following order: ADP = AMP-PNP > ATP = ADP.AlF(4) > ADP.BeF(x)() > PP(i). By contrast, rigor binding to F-actin increased the yield to 130%. In the ternary acto-S-1-ADP complex, the yield was again reduced to 80%, and it fell to 25% in acto-S-1-ADP.AlF(4), the putative transition state analogue complex of the acto-S-1 ATPase. These different quantitative changes reflect distinct ligand-induced conformations of the secondary structure element whose scission generates the 54 kDa-40 kDa species. According to the S-1 crystal structure, this element could

  10. The application of EDTA in drug delivery systems: doxorubicin liposomes loaded via NH4EDTA gradient.

    PubMed

    Song, Yanzhi; Huang, Zhenjun; Song, Yang; Tian, Qingjing; Liu, Xinrong; She, Zhennan; Jiao, Jiao; Lu, Eliza; Deng, Yihui

    2014-01-01

    The applications of ethylenediaminetetraacetic acid (EDTA) have been expanded from the treatment of heavy metal poisoning to chelation therapies for atherosclerosis, heart disease, and cancers, in which EDTA reduces morbidity and mortality by chelating toxic metal ions. In this study, EDTA was used in a drug delivery system by adopting an NH4EDTA gradient method to load doxorubicin into liposomes with the goal of increasing therapeutic effects and decreasing drug-related cytotoxicity. The particle size of the optimum NH4EDTA gradient liposomes was 79.4±1.87 nm, and the entrapment efficiency was 95.54%±0.59%. In vitro studies revealed that liposomes prepared using an NH4EDTA gradient possessed long-term stability and delayed drug release. The in vivo studies also showed the superiority of the new doxorubicin formulation. Compared with an equivalent drug dose (5 mg/kg) prepared by (NH4)2SO4 gradient, NH4EDTA gradient liposomes showed no significant differences in tumor inhibition ratio, but cardiotoxicity and liposome-related immune organ damage were lower, and no drug-related deaths were observed. These results show that use of the NH4EDTA gradient method to load doxorubicin into liposomes could significantly reduce drug toxicity without influencing antitumor activity.

  11. Gallium-68 EDTA PET/CT for Renal Imaging.

    PubMed

    Hofman, Michael S; Hicks, Rodney J

    2016-09-01

    Nuclear medicine renal imaging provides important functional data to assist in the diagnosis and management of patients with a variety of renal disorders. Physiologically stable metal chelates like ethylenediaminetetraacetic acid (EDTA) and diethylenetriamine penta-acetate (DTPA) are excreted by glomerular filtration and have been radiolabelled with a variety of isotopes for imaging glomerular filtration and quantitative assessment of glomerular filtration rate. Gallium-68 ((68)Ga) EDTA PET usage predates Technetium-99m ((99m)Tc) renal imaging, but virtually disappeared with the widespread adoption of gamma camera technology that was not optimal for imaging positron decay. There is now a reemergence of interest in (68)Ga owing to the greater availability of PET technology and use of (68)Ga to label other radiotracers. (68)Ga EDTA can be used a substitute for (99m)Tc DTPA for wide variety of clinical indications. A key advantage of PET for renal imaging over conventional scintigraphy is 3-dimensional dynamic imaging, which is particularly helpful in patients with complex anatomy in whom planar imaging may be nondiagnostic or difficult to interpret owing to overlying structures containing radioactive urine that cannot be differentiated. Other advantages include accurate and absolute (rather than relative) camera-based quantification, superior spatial and temporal resolution and integrated multislice CT providing anatomical correlation. Furthermore, the (68)Ga generator enables on-demand production at low cost, with no additional patient radiation exposure compared with conventional scintigraphy. Over the past decade, we have employed (68)Ga EDTA PET/CT primarily to answer difficult clinical questions in patients in whom other modalities have failed, particularly when it was envisaged that dynamic 3D imaging would be of assistance. We have also used it as a substitute for (99m)Tc DTPA if unavailable owing to supply issues, and have additionally examined the role of

  12. Photoelectrocatalytic oxidation of Cu(II)-EDTA at the TiO2 electrode and simultaneous recovery of Cu(II) by electrodeposition.

    PubMed

    Zhao, Xu; Guo, Libao; Zhang, Baofeng; Liu, Huijuan; Qu, Jiuhui

    2013-05-01

    The simultaneous decomplexation of Cu-EDTA and electrodeposition recovery of Cu(2+) ions was attempted in a photoelectrocatalytic (PEC) system using TiO2/Ti as the anode and stainless steel as the cathode. At a current density of 0.5 mA/cm(2), removal efficiencies of 0.05 mM Cu-EDTA by photocatalysis, electrooxidation, and PEC processes were determined to be 15, 43, and 72% at 3 h, respectively. Recovery percentages of Cu(2+) ions were determined to be 10, 33, and 67%, respectively. These results indicated that a synergetic effect in the decomplexation of Cu-EDTA and recovery of Cu(2+) ions occurred in the PEC process, which favored acid conditions and increased with the current densities. The removal of Cu-EDTA and Cu(2+) ions can be described by a pseudo-first-order kinetics model. Ca(2+) ions significantly increase the removal of Cu-EDTA and recovery of Cu(2+) ions. Intermediates, including Cu-NTA, Cu-EDDA, acetic acid, formic acid, and oxalic acid, were identified, and a decomplexation pathway of Cu-EDTA was proposed. The Cu-EDTA decomplexation at the anode via oxidation of hydroxyl radicals was revealed. On the basis of X-ray photoelectron spectra analysis, a reduction pathway of Cu(2+) ions at the cathode was discussed. The present study may provide a promising alternative for destruction of the metal complex and recovery of metal ions.

  13. Mean platelet volume measurement, EDTA or citrate?

    PubMed

    Dastjerdi, Mansour Siavash; Emami, Tajolmolouk; Najafian, Alireza; Amini, Masoud

    2006-10-01

    Most laboratories use EDTA for anticoagulation of whole blood prior to automated cell counting but due to platelet swelling, mean platelet volume (MPV) values may increase with its use. MPV changes may be less with acid citrate based anticoagulation. As MPV is a marker of platelet function and its precise measurement is important in a number of clinical situations, this study was performed to assess if EDTA and citrate based anticoagulated blood samples can be used interchangeably for MPV measurement. In this cross sectional descriptive study, EDTA and citrate based anticoagulated blood samples of the same patients were assessed by auto-analyzer within 1 h of sampling. In the 61 evaluated patients, there was a close correlation between MPV as measured by EDTA and citrate, but mean MPV measured from EDTA samples was 0.66 fL (9%) more than citrate. There was also a significant negative correlation between platelets count and MPV by both methods. The results of our study reveal that MPV can be measured accurately by both methods of anticoagulation; EDTA and citrate if analysis be performed within 1 h of sampling. PMID:17607580

  14. Effect Of EDTA On Luminescence Property Of Eu{sup +3} Doped YPO{sub 4} Nanoparticles

    SciTech Connect

    Parchur, A. K.; Okram, G. S.; Singh, R. A.; Tewari, R.; Pradhan, Lina; Vatsa, R. K.; Ningthoujam, R. S.

    2010-12-01

    Nanoparticles of Eu{sup 3+} doped YPO{sub 4} have been prepared using ethylene glycol (EG). Ethylene diamine tetra acetic acid (EDTA) is used as a complexing agent. X-ray diffraction results show that the nanoparticles are crystalline in tetragonal structure. Based on William-Hall relation, the effective crystallite size and strain developed in lattice are found to be 28 nm and 0.002, respectively. With the addition of EDTA, there is a slight shift towards the lower wavelength in emission peaks. Asymmetric ratio of electric to magnetic dipole transition intensities are found to decrease with addition of EDTA. Emission intensity decreases with EDTA because of decrease of particle size as well as decrease of number of Eu{sup 3+} activators per unit volume. These materials are dispersible in water, which may have potential biological applications.

  15. The control of nitrilotriacetic acid in edetic acid and its salts by liquid chromatography.

    PubMed

    Crosbie, G A; Lodi, A; McB Miller, J H; Skellern, G G

    2003-10-15

    Two liquid chromatographic methods have been developed and validated for the determination of nitrilotriacetic acid (NTA) in edetic acid (EDTA) and its salts. In one method NTA and EDTA are separated on a polymer column without pretreatment, and are detected amperometrically using a glassy-carbon electrode. In the other method NTA and EDTA are complexed with ferric ions and the complexes separated on a porous graphite carbon stationary phase with ultraviolet detection at 215 nm. Both methods were sufficiently selected and sensitive to allow the control of NTA (0.1% m/m) in sample of EDTA and its salts.

  16. Outer Sphere Adsorption of Pb(II)EDTA on Goethite

    SciTech Connect

    Bargar, John R

    1999-07-16

    FTIR and EXAFS spectroscopic measurements were performed on Pb(II)EDTA adsorbed on goethite as functions of pH (4-6), Pb(II)EDTA concentration (0.11 {micro}M - 72 {micro}M), and ionic strength (16 {micro}M - 0.5M). FTIR measurements show no evidence for carboxylate-Fe(III) bonding or protonation of EDTA at Pb:EDTA = 1:1. Both FTIR and EXAFS measurements suggest that EDTA acts as a hexadentate ligand, with all four of its carboxylate and both amine groups bonded to Pb(II). No evidence was observed for inner-sphere Pb(II)-goethite bonding at Pb:EDTA = 1:1. Hence, the adsorbed complexes should have composition Pb(II)EDTA{sup 2{minus}}. Since substantial uptake of PbEDTA(II){sup 2{minus}} occurred in the samples, we infer that Pb(II)EDTA{sup 2{minus}} adsorbed as outer-sphere complexes and/or as complexes that lose part of their solvation shells and hydrogen bond directly to goethite surface sites. We propose the term ''hydration-sphere'' for the latter type of complexes because they should occupy space in the primary hydration spheres of goethite surface functional groups, and to distinguish this mode of sorption from common structural definitions of inner- and outer-sphere complexes. The similarity of Pb(II) uptake isotherms to those of other divalent metal ions complexed by EDTA suggests that they too adsorb by these mechanisms. The lack of evidence for inner-sphere EDTA-Fe(III) bonding suggests that previously proposed metal-ligand - promoted dissolution mechanisms should be modified, specifically to account for the presence of outer-sphere precursor species.

  17. Impact of extra virgin olive oil and ethylenediaminetetraacetic acid (EDTA) on the oxidative stability of fish oil emulsions and spray-dried microcapsules stabilized by sugar beet pectin.

    PubMed

    Polavarapu, Sudheera; Oliver, Christine M; Ajlouni, Said; Augustin, Mary Ann

    2012-01-11

    The influence of EDTA on lipid oxidation in sugar beet pectin-stabilized oil-in-water emulsions (pH 6, 15% oil, wet basis), prepared from fish oil (FO) and fish oil-extra virgin olive oil (FO-EVOO) (1:1 w/w), as well as the spray-dried microcapsules (50% oil, dry basis) prepared from these emulsions, was investigated. Under accelerated conditions (80 °C, 5 bar oxygen pressure) the oxidative stability was significantly (P < 0.05) higher for FO and FO-EVOO formulated with EDTA, in comparison to corresponding emulsions and spray-dried microcapsules formulated without EDTA. The EDTA effect was greater in emulsions than in spray-dried microcapsules, with the greatest protective effect obtained in FO-EVOO emulsions. EDTA enhanced the oxidative stability of the spray-dried microcapsules during ambient storage (~25 °C, a(w) = 0.5), as demonstrated by their lower concentration of headspace volatile oxidation products, propanal and hexanal. These results show that the addition of EDTA is an effective strategy to maximize the oxidative stability of both FO emulsions and spray-dried microcapsules in which sugar beet pectin is used as the encapsulant material.

  18. Biodegradation of PuEDTA and Impacts on Pu Mobility

    SciTech Connect

    Xun, Luying; Bolton, Jr., Harvey

    2002-06-01

    This project, by Dr. Xun, supports work at PNNL (Bolton) regarding plutonium mobility in the subsurface. Ethylenediaminetetraacetate (EDTA) is a chelating agent that can increase the mobility of radionuclides and heavy metals in groundwater. Biodegradation of EDTA can decrease the enhanced mobility. The overall objective is to understand how microbial degradation affects Plutonium-EDTA transport in the environment and the specific objective of this component is to understand how microorganisms degrade EDTA. A chelating degrading bacterium BNC1 can use EDTA and nitrilotriacetate (NTA) as sole carbon and nitrogen sources. A gene cluster responsible for both EDTA and NTA degradation has been cloned and characterized (1,2). The same enzymes are used to degrade both compounds except that additional enzymes are required for EDTA degradation. Since the enzymes are located inside cells, EDTA and NTA must be transported into cells for degradation. For the first funding year, we have focused on how EDTA and NTA are transported into BNC1 cells. The EDTA-degrading gene cluster also contains genes encoding a hypothetical ABC-type transporter. We first demonstrated that the transporter genes and EDTA monooxygenase gene (emoA) were co-transcribed by RT-PCR, suggesting that the genes are involved in EDTA transport. We then characterized one of the gene product EppA. Using recombinant EppA purified from Escherichia coli, we have shown that EppA binds several metal:EDTA complexes by fluorescence techniques. In addition, EppA is shown to bind Mg:NTA, Ca:NTA and Fe(III):NTA but not free NTA.

  19. Cyclohexyl EDTA monoanhydride

    DOEpatents

    Mease, R.C.; Srivastava, S.C.

    1991-06-04

    The present invention relates to new rigid chelating structures, to methods for preparing these materials, and to their use in preparing radiometal labeled immunoconjugates. These new chelates include cyclohexyl EDTA monohydride, the transforms of cyclohexyl DTPA and TTHA and derivatives of these cyclohexyl polyaminocarboxylate materials. No Drawings

  20. Cyclohexyl EDTA monoanhydride

    DOEpatents

    Mease, Ronnie C.; Srivastava, Suresh C.

    1991-01-01

    The present invention relates to new rigid chelating structures, to methods for preparing these materials, and to their use in preparing radiometal labeled immunoconjugates. These new chelates include cyclohexyl EDTA monohydride, the transforms of cyclohexyl DTPA and TTHA and derivatives of these cyclohexyl polyaminocarboxylate materials.

  1. Anaerobic Biotransformation and Mobility of Pu and Pu-EDTA

    SciTech Connect

    Bolton, H., Jr.; Bailey, V.L.; Plymale, A.E.; Rai, D.; Xun, L.

    2006-04-05

    The complexation of radionuclides (e.g., plutonium (Pu) and {sup 60}Co) by co-disposed ethylenediaminetetraacetate (EDTA) has enhanced their transport in sediments at DOE sites. Pu(IV)-EDTA is not stable in the presence of relatively soluble Fe(III) compounds. Since most DOE sites have Fe(III) containing sediments, Pu(IV) is likely not the mobile form of Pu-EDTA. The only other Pu-EDTA complex stable in groundwater relevant to DOE sites would be Pu(III)-EDTA, which only forms under anaerobic conditions. Research is therefore needed to investigate the biotransformation of Pu and Pu-EDTA under anaerobic conditions and the anaerobic biodegradation of Pu-EDTA. The biotransformation of Pu and Pu-EDTA under various anaerobic regimes is poorly understood including the reduction kinetics of Pu(IV) to Pu(III) from soluble (Pu(IV)-EDTA) and insoluble Pu(IV), the redox conditions required for this reduction, the strength of the Pu(III)-EDTA, how the Pu(III)-EDTA competes with other dominant anoxic soluble metals (e.g., Fe(II)), and the oxidation kinetics of Pu(III)-EDTA. Finally, soluble Pu(III)-EDTA under anaerobic conditions would require anaerobic degradation of the EDTA to limit Pu(III) transport. Anaerobic EDTA degrading microorganisms have never been isolated. Recent results have shown that Shewanella oneidensis MR-1, a dissimilatory metal reducing bacterium, can reduce Pu(IV) to Pu(III). The Pu(IV) was provided as insoluble PuO2. The highest rate of Pu(IV) reduction was with the addition of AQDS, an electron shuttle. Of the total amount of Pu solubilized (i.e., soluble through a 0.36 nm filter), approximately 70% was Pu(III). The amount of soluble Pu was between 4.8 and 3.2 micromolar at day 1 and 6, respectively, indicating rapid reduction. The micromolar Pu is significant since the drinking water limit for Pu is 10{sup -12} M. On-going experiments are investigating the influence of EDTA on the rate of Pu reduction and the stability of the formed Pu(III). We have also

  2. Pd/RGO modified carbon felt cathode for electro-Fenton removing of EDTA-Ni.

    PubMed

    Zhang, Zhen; Zhang, Junya; Ye, Xiaokun; Hu, Yongyou; Chen, Yuancai

    2016-01-01

    Ethylenediaminetetraacetic acid (EDTA) forms stable complexes with toxic metals such as nickel due to its strong chelation. The electro-Fenton (EF) process using a cathode made from palladium (Pd), reduced graphene oxide (RGO) and carbon felt, fed with air, exhibited high activities and stability for the removal of 10 mg L(-1) EDTA-Ni solution. Pd/RGO catalyst was prepared by one-pot synthesis; the scanning electron microscopy and X-ray diffraction analysis indicated nanoparticles and RGO were well distributed on carbon felt, forming three dimensional architecture with both large macropores and a mesoporous structure. The cyclic voltammetric results showed that the presence of RGO in Pd/RGO/carbon felt significantly increased the current response of two-electron reduction of O2 (0.45 V). The key factors influencing the removal efficiency of EDTA-Ni, such as pH, current and Fe(2+) concentration, were investigated. Under the optimum conditions, the removal efficiency of EDTA-Ni reached 83.8% after 100 min EF treatment. Mechanism analysis indicated that the introduction of RGO in Pd/RGO/carbon felt significantly enhanced the electrocatalytic activities by inducing •OH in the EF process; direct H2O2 oxidation still accounted for a large amount of EDTA-Ni removal efficiency. PMID:27508368

  3. Radical-generating coordination complexes as tools for rapid and effective fragmentation and fluorescent labeling of nucleic acids for microchip hybridization.

    SciTech Connect

    Kelly, J. J.; Chernov, B. K.; Tovstanovsky, I.; Mirzabekov, A. D.; Bavykin, S. G.; Biochip Technology Center; Northwestern Univ.; Engelhardt Inst. of Molecular Biology

    2002-12-15

    DNA microchip technology is a rapid, high-throughput method for nucleic acid hybridization reactions. This technology requires random fragmentation and fluorescent labeling of target nucleic acids prior to hybridization. Radical-generating coordination complexes, such as 1,10-phenanthroline-Cu(II) (OP-Cu) and Fe(II)-EDTA (Fe-EDTA), have been commonly used as sequence nonspecific 'chemical nucleases' to introduce single-strand breaks in nucleic acids. Here we describe a new method based on these radical-generating complexes for random fragmentation and labeling of both single- and double-stranded forms of RNA and DNA. Nucleic acids labeled with the OP-Cu and the Fe-EDTA protocols revealed high hybridization specificity in hybridization with DNA microchips containing oligonucleotide probes selected for identification of 16S rRNA sequences of the Bacillus group microorganisms.We also demonstrated cDNA- and cRNA-labeling and fragmentation with this method. Both the OP-Cu and Fe-EDTA fragmentation and labeling procedures are quick and inexpensive compared to other commonly used methods. A column-based version of the described method does not require centrifugation and therefore is promising for the automation of sample preparations in DNA microchip technology as well as in other nucleic acid hybridization studies.

  4. Effect of agitation of EDTA with 808-nm diode laser on dentin microhardness.

    PubMed

    Arslan, Hakan; Yeter, Kübra Y; Karatas, Ertugrul; Yilmaz, Cenk B; Ayranci, Leyla B; Ozsu, Damla

    2015-02-01

    The aim of this study is to analyze the effect of agitation of ethylenediaminetetraacetic acid (EDTA) with diode laser at different agitation times on root dentin microhardness. Eighty-four specimens were divided randomly into seven groups, as follows: (1) distilled water, (2) 17% EDTA, (3) EDTA with 60 s ultrasonic agitation, (4) EDTA with 10 s laser agitation, (5) EDTA with 20 s laser agitation, (6) EDTA with 30 s laser agitation, and (7) EDTA with 40 s laser agitation. All of the specimens were irrigated with 5% NaOCl and distilled water except the distilled water group. Microhardness values were calculated before and after the procedures. Statistical analyses were performed using one-way ANOVA and Tukey post hoc tests. Statistically significant differences were determined between the distilled water and other groups. Also, statistically significant differences were observed between EDTA with 40 s laser agitation and EDTA, and EDTA with 10 and 20 s laser agitations. Ultrasonic agitation of EDTA affected microhardness of root dentin similar to EDTA (p > .05). All applications decreased the microhardness of root dentin when compared with distilled water. Agitation of EDTA with diode laser for 40 s caused more reduction in microhardness of root dentin when compared with EDTA.

  5. Effect of agitation of EDTA with 808-nm diode laser on dentin microhardness.

    PubMed

    Arslan, Hakan; Yeter, Kübra Y; Karatas, Ertugrul; Yilmaz, Cenk B; Ayranci, Leyla B; Ozsu, Damla

    2015-02-01

    The aim of this study is to analyze the effect of agitation of ethylenediaminetetraacetic acid (EDTA) with diode laser at different agitation times on root dentin microhardness. Eighty-four specimens were divided randomly into seven groups, as follows: (1) distilled water, (2) 17% EDTA, (3) EDTA with 60 s ultrasonic agitation, (4) EDTA with 10 s laser agitation, (5) EDTA with 20 s laser agitation, (6) EDTA with 30 s laser agitation, and (7) EDTA with 40 s laser agitation. All of the specimens were irrigated with 5% NaOCl and distilled water except the distilled water group. Microhardness values were calculated before and after the procedures. Statistical analyses were performed using one-way ANOVA and Tukey post hoc tests. Statistically significant differences were determined between the distilled water and other groups. Also, statistically significant differences were observed between EDTA with 40 s laser agitation and EDTA, and EDTA with 10 and 20 s laser agitations. Ultrasonic agitation of EDTA affected microhardness of root dentin similar to EDTA (p > .05). All applications decreased the microhardness of root dentin when compared with distilled water. Agitation of EDTA with diode laser for 40 s caused more reduction in microhardness of root dentin when compared with EDTA. PMID:23793370

  6. Anaerobic Biotransformation and Mobility of Pu and of Pu-EDTA

    SciTech Connect

    Xun, Luying

    2009-11-20

    The enhanced mobility of radionuclides by co-disposed chelating agent, ethylenediaminetetraacetate (EDTA), is likely to occur only under anaerobic conditions. Our extensive effort to enrich and isolate anaerobic EDTA-degrading bacteria has failed. Others has tried and also failed. To explain the lack of anaerobic biodegradation of EDTA, we proposed that EDTA has to be transported into the cells for metabolism. A failure of uptake may contribute to the lack of EDTA degradation under anaerobic conditions. We demonstrated that an aerobic EDTA-degrading bacterium strain BNC1 uses an ABC-type transporter system to uptake EDTA. The system has a periplasmic binding protein that bind EDTA and then interacts with membrane proteins to transport EDTA into the cell at the expense of ATP. The bind protein EppA binds only free EDTA with a Kd of 25 nM. The low Kd value indicates high affinity. However, the Kd value of Ni-EDTA is 2.4 x 10^(-10) nM, indicating much stronger stability. Since Ni and other trace metals are essential for anaerobic respiration, we conclude that the added EDTA sequestrates all trace metals and making anaerobic respiration impossible. Thus, the data explain the lack of anaerobic enrichment cultures for EDTA degradation. Although we did not obtain an EDTA degrading culture under anaerobic conditions, our finding may promote the use of certain metals that forms more stable metal-EDTA complexes than Pu(III)-EDTA to prevent the enhanced mobility. Further, our data explain why EDTA is the most dominant organic pollutant in surface waters, due to the lack of degradation of certain metal-EDTA complexes.

  7. Direct evidence for catalase activity of [Ru(V)(edta)(O)](-).

    PubMed

    Chatterjee, Debabrata; Jaiswal, Namita; Franke, Alicja; van Eldik, Rudi

    2014-12-01

    Reported is the first example of a ruthenium(III) complex, Ru(III)(edta) (edta(4-) = ethylenediaminetetraacetate), that catalyzes the disproportion of H2O2 to O2 and water in resemblance to catalase activity, and shedding light on the possible mechanism of action of the [Ru(V)(edta)(O)](-) formed in the reacting system. PMID:25307989

  8. How phytohormone IAA and chelator EDTA affect lead uptake by Zn/Cd hyperaccumulator Picris divaricata.

    PubMed

    Du, Rui-Jun; He, Er-Kai; Tang, Ye-Tao; Hu, Peng-Jie; Ying, Rong-Rong; Morel, Jean-Louis; Qiu, Rong-Liang

    2011-01-01

    In this paper, the effects of indole-3-acetic acid (IAA) and/or ethylenediaminetetraacetic acid (EDTA) on lead uptake by a Zn/Cd hyperaccumulator Picris divaricata were studied. P. divaricata responded to Pb by better root system and increased biomass in presence of phytohormone IAA, which was able to reduce the inhibiting effects of Pb on transpiration without reducing the uptake of Pb The application of 100 microM IAA increased plant transpiration rate by about 20% and Pb concentration in leaves by about 37.3% as compared to treatment exposed to Pb alone. The enhanced phytoextraction efficiency could be attributed to the mechanisms played by IAA through alleviating Pb toxicity, creating better root system and plant biomass, promoting a higher transpiration rate as well as regulating the level of nutrient elements. On the contrary, inefficiency of phytoextraction was found with EDTA or the combination of IAA and EDTA probably because most Pb was in the form of Pb-EDTA complex which blocked the uptake by P. divaricata. The present study demonstrated that IAA was able to enhance the phytoextraction of Pb by Zn/Cd hyperaccumulator P. divaricata, providing a feasible method for the phytoremediation of polymetallic contaminated soils. PMID:21972569

  9. Determination of EDTA in feed and premix formulations by HPLC-DAD.

    PubMed

    Chiumiento, Francesco; D'Aloise, Antonio; Marchegiani, Francesca; Melai, Valeria

    2015-05-15

    A simple analytical method for the quantitative determination of ethylenediaminetetraacetic acid (EDTA) in feed and premix formulations was developed and validated. The method involves an extraction with an acidic ferric chloride solution, to quantitatively convert EDTA species in the samples into the Fe(III)-EDTA complex, and its subsequent detection by Ion-Pair-Reversed Phase-High Performance Liquid Chromatography-Diode Array Detection (IP-RP-HPLC-DAD). A robust validation procedure was performed according to the Decision 2002/657/EC at concentrations ranging from 25 to 100 mg kg(-1) on sample. Good recoveries (85.6-92.8%) were obtained; repeatability of the method was in the range of 1.3-8.0%, with an intermediate precision ranging from 6.0% to 8.6%, both of them expressed as relative standard deviation (RSD). No interfering species hindered the straightforward detection of EDTA. Hence, the proposed method can be adopted for an effective and rapid routine analysis of products for livestock.

  10. Thermodynamic and Spectroscopic Studies of Trivalent f -element Complexation with Ethylenediamine- N,N '-di(acetylglycine)- N,N '-diacetic Acid

    DOE PAGES

    Heathman, Colt R.; Grimes, Travis S.; Zalupski, Peter R.

    2016-03-21

    In this study, the coordination behavior and thermodynamic features of complexation of trivalent lanthanides and americium by ethylenediamine-N,N'-di(acetylglycine)-N,N'-diacetic acid (EDDAG-DA) (bisamide-substituted-EDTA) were investigated by potentiometric and spectroscopic techniques. Acid dissociation constants (Ka) and complexation constants (β) of lanthanides (except Pm) were determined by potentiometric analysis. Absorption spectroscopy was used to determine stability constants for the binding of trivalent americium and neodymium by EDDAG-DA under similar conditions. The potentiometry revealed 5 discernible protonation constants and 3 distinct metal–ligand complexes (identified as ML–, MHL, and MH2L+). Time-resolved fluorescence studies of Eu-(EDDAG-DA) solutions (at varying pH) identified a constant inner-sphere hydration number ofmore » 3, suggesting that glycine functionalities contained in the amide pendant arms are not involved in metal complexation and are protonated under more acidic conditions. The thermodynamic studies identified that f-element coordination by EDDAG-DA is similar to that observed for ethylenediamine-N,N,N',N'-tetraacetic acid (EDTA). However, coordination via two amidic oxygens of EDDAG-DA lowers its trivalent f-element complex stability by roughly 3 orders of magnitude relative to EDTA.« less

  11. Thermodynamic and Spectroscopic Studies of Trivalent f-element Complexation with Ethylenediamine-N,N'-di(acetylglycine)-N,N'-diacetic Acid.

    PubMed

    Heathman, Colt R; Grimes, Travis S; Zalupski, Peter R

    2016-03-21

    The coordination behavior and thermodynamic features of complexation of trivalent lanthanides and americium by ethylenediamine-N,N'-di(acetylglycine)-N,N'-diacetic acid (EDDAG-DA) (bisamide-substituted-EDTA) were investigated by potentiometric and spectroscopic techniques. Acid dissociation constants (K(a)) and complexation constants (β) of lanthanides (except Pm) were determined by potentiometric analysis. Absorption spectroscopy was used to determine stability constants for the binding of trivalent americium and neodymium by EDDAG-DA under similar conditions. The potentiometry revealed 5 discernible protonation constants and 3 distinct metal-ligand complexes (identified as ML(-), MHL, and MH2L(+)). Time-resolved fluorescence studies of Eu-(EDDAG-DA) solutions (at varying pH) identified a constant inner-sphere hydration number of 3, suggesting that glycine functionalities contained in the amide pendant arms are not involved in metal complexation and are protonated under more acidic conditions. The thermodynamic studies identified that f-element coordination by EDDAG-DA is similar to that observed for ethylenediamine-N,N,N',N'-tetraacetic acid (EDTA). However, coordination via two amidic oxygens of EDDAG-DA lowers its trivalent f-element complex stability by roughly 3 orders of magnitude relative to EDTA. PMID:26930023

  12. Determination of cobalt(II)-EDTA, cobalt(III)-EDTA, and cobalt(II) in an aqueous solution

    SciTech Connect

    Ayres, D.M.; Davis, A.P.

    1996-11-01

    The determination of Co-EDTA species is critical to the understanding of radionuclide migration in the environment, as well as determining efficiencies of various complexed-Co treatment technologies. A new, simple column-oxidation separation methodology was devised to determine the fraction of uncomplexed Co(II), Co(II)-EDTA, and Co(III)-EDTA in an aqueous mixture. A Dowex 50W (H{sup +}) ion-exchange resin, and the oxidative conversion of residual Co(II)-EDTA to Co(III)-EDTA using H{sub 2}O{sub 2}, allowed the separation of species fractions. Only atomic absorption spectrophotometric measurements were required after separation of the fractions. Analysis of individual Co species separated from mixtures ranging in concentration from 3 {times} 10{sup {minus}5} to 3 {times} 10{sup {minus}3} M total Co resulted in average recoveries of 97 {plus_minus} 4%. 15 refs., 2 tabs.

  13. Transport of Sr2+ and SrEDTA2- in partially-saturated and heterogeneous sediments.

    PubMed

    Pace, M N; Mayes, M A; Jardine, P M; McKay, L D; Yin, X L; Mehlhorn, T L; Liu, Q; Gürleyük, H

    2007-05-14

    Strontium-90 has migrated deep into the unsaturated subsurface beneath leaking storage tanks in the Waste Management Areas (WMA) at the U.S. Department of Energy's (DOE) Hanford Reservation. Faster than expected transport of contaminants in the vadose zone is typically attributed to either physical hydrologic processes such as development of preferential flow pathways, or to geochemical processes such as the formation of stable, anionic complexes with organic chelates, e.g., ethylenediaminetetraacetic acid (EDTA). The goal of this paper is to determine whether hydrological processes in the Hanford sediments can influence the geochemistry of the system and hence control transport of Sr(2+) and SrEDTA(2-). The study used batch isotherms, saturated packed column experiments, and an unsaturated transport experiment in an undisturbed core. Isotherms and repacked column experiments suggested that the SrEDTA(2-) complex was unstable in the presence of Hanford sediments, resulting in dissociation and transport of Sr(2+) as a divalent cation. A decrease in sorption with increasing solid:solution ratio for Sr(2+) and SrEDTA(2-) suggested mineral dissolution resulted in competition for sorption sites and the formation of stable aqueous complexes. This was confirmed by detection of MgEDTA(2-), MnEDTA(2-), PbEDTA(2-), and unidentified Sr and Ca complexes. Displacement of Sr(2+) through a partially-saturated undisturbed core resulted in less retardation and more irreversible sorption than was observed in the saturated repacked columns, and model results suggested a significant reservoir (49%) of immobile water was present during transport through the heterogeneous layered sediments. The undisturbed core was subsequently disassembled along distinct bedding planes and subjected to sequential extractions. Strontium was unequally distributed between carbonates (49%), ion exchange sites (37%), and the oxide (14%) fraction. An inverse relationship between mass wetness and Sr suggested

  14. Determination of hydrogen ion by ion chromatography (IC) with sulfonated cation-exchange resin as the stationary phase and aqueous EDTA (ethylenediamine-N,N,N',N'-tetraacetic acid) solution as the mobile phase.

    PubMed

    Hu, W; Iles, A; Hasebe, K; Matsukami, H; Cao, S; Tanaka, K

    2001-05-01

    An ion chromatographic (IC) method has been developed for determination of hydrogen ion (H+). It is based on the use of sulfonated cation-exchange resin as stationary phase, aqueous ethylenediamine-N,N,N',N'-tetraacetic acid (dipotassium salt, EDTA-2K, written as K2H2Y) solution as mobile phase, and conductivity for detection. H+ was separated mainly by cation-exchange, but its elution was accelerated by the presence of EDTA. The order of elution for the model cations was H+ > Li+ > Na+ > NH4+ > Ca2+ > > Mg2+. A sharp and highly symmetrical peak was obtained for H+ and this was attributed to the capacity of H2Y2(2-) to receive and bind H+. H+ was detected conductiometrically and detector response (reduction in conductivity as a result of H+ +H2Y2- --> H3Y-) was linearly proportional to the concentration of H+ in the sample. The detection limit for H+ with this IC system was better than 4.7 micromol L(-1). A significant advantage of this method was the ability to separate and determine, in one step, H+ and other cations. The successful determination of H+ and other cation species in real acid-rain samples demonstrated the usefulness of this method.

  15. Enhanced electrokinetic remediation of lead-contaminated soil by complexing agents and approaching anodes.

    PubMed

    Zhang, Tao; Zou, Hua; Ji, Minhui; Li, Xiaolin; Li, Liqiao; Tang, Tang

    2014-02-01

    Optimizing process parameters that affect the remediation time and power consumption can improve the treatment efficiency of the electrokinetic remediation as well as determine the cost of a remediation action. Lab-scale electrokinetic remediation of Pb-contaminated soils was investigated for the effect of complexant ethylenediaminetetraacetic acid (EDTA) and acetic acid and approaching anode on the removal efficiency of Pb. When EDTA was added to the catholyte, EDTA dissolved insoluble Pb in soils to form soluble Pb-EDTA complexes, increasing Pb mobility and accordingly removal efficiency. The removal efficiency was enhanced from 47.8 to 61.5 % when the EDTA concentration was increased from 0.1 to 0.2 M, showing that EDTA played an important role in remediation. And the migration rate of Pb was increased to 72.3 % when both EDTA and acetic acid were used in the catholyte. The "approaching anode electrokinetic remediation" process in the presence of both EDTA and acetic acid had a higher Pb-removal efficiency with an average efficiency of 83.8 %. The efficiency of electrokinetic remediation was closely related to Pb speciation. Exchangeable and carbonate-bounded Pb were likely the forms which could be removed. All results indicate that the approaching anode method in the presence of EDTA and acetic acid is an advisable choice for electrokinetic remediation of Pb-contaminated soil. PMID:24203258

  16. Sodium iron EDTA and ascorbic acid, but not polyphenol oxidase treatment, counteract the strong inhibitory effect of polyphenols from brown sorghum on the absorption of fortification iron in young women.

    PubMed

    Cercamondi, Colin I; Egli, Ines M; Zeder, Christophe; Hurrell, Richard F

    2014-02-01

    In addition to phytate, polyphenols (PP) might contribute to low Fe bioavailability from sorghum-based foods. To investigate the inhibitory effects of sorghum PP on Fe absorption and the potential enhancing effects of ascorbic acid (AA), NaFeEDTA and the PP oxidase enzyme laccase, we carried out three Fe absorption studies in fifty young women consuming dephytinised Fe-fortified test meals based on white and brown sorghum varieties with different PP concentrations. Fe absorption was measured as the incorporation of stable Fe isotopes into erythrocytes. In study 1, Fe absorption from meals with 17 mg PP (8·5%) was higher than that from meals with 73 mg PP (3·2%) and 167 mg PP (2·7%; P< 0·001). Fe absorption from meals containing 73 and 167 mg PP did not differ (P= 0·9). In study 2, Fe absorption from NaFeEDTA-fortified meals (167 mg PP) was higher than that from the same meals fortified with FeSO₄ (4·6 v. 2·7%; P< 0·001), but still it was lower than that from FeSO₄-fortified meals with 17 mg PP (10·7%; P< 0·001). In study 3, laccase treatment decreased the levels of PP from 167 to 42 mg, but it did not improve absorption compared with that from meals with 167 mg PP (4·8 v. 4·6%; P= 0·4), whereas adding AA increased absorption to 13·6% (P< 0·001). These findings suggest that PP from brown sorghum contribute to low Fe bioavailability from sorghum foods and that AA and, to a lesser extent, NaFeEDTA, but not laccase, have the potential to overcome the inhibitory effect of PP and improve Fe absorption from sorghum foods.

  17. Iron bioavailability from a lipid-based complementary food fortificant mixed with millet porridge can be optimized by adding phytase and ascorbic acid but not by using a mixture of ferrous sulfate and sodium iron EDTA.

    PubMed

    Cercamondi, Colin I; Egli, Ines M; Mitchikpe, Evariste; Tossou, Felicien; Hessou, Joamel; Zeder, Christophe; Hounhouigan, Joseph D; Hurrell, Richard F

    2013-08-01

    Home fortification with lipid-based nutrient supplements (LNSs) is a promising approach to improve bioavailable iron and energy intake of young children in developing countries. To optimize iron bioavailability from an LNS named complementary food fortificant (CFF), 3 stable isotope studies were conducted in 52 young Beninese children. Test meals consisted of millet porridge mixed with CFF and ascorbic acid (AA). Study 1 compared iron absorption from FeSO4-fortifed meals with meals fortified with a mixture of FeSO4 and NaFeEDTA. Study 2 compared iron absorption from FeSO4-fortifed meals without or with extra AA. Study 3 compared iron absorption from FeSO4-fortified meals with meals containing phytase added prior to consumption, once without or once with extra AA. Iron absorption was measured as erythrocyte incorporation of stable isotopes. In study 1, iron absorption from FeSO4 (8.4%) was higher than that from the mixture of NaFeEDTA and FeSO4 (5.9%; P < 0.05). In study 2, the extra AA increased absorption (11.6%) compared with the standard AA concentration (7.3%; P < 0.001). In study 3, absorption from meals containing phytase without or with extra AA (15.8 and 19.9%, respectively) increased compared with meals without phytase (8.0%; P < 0.001). The addition of extra AA to meals containing phytase increased absorption compared with the test meals containing phytase without extra AA (P < 0.05). These findings suggest that phytase and AA, and especially a combination of the two, but not a mixture of FeSO4 and NaFeEDTA would be useful strategies to increase iron bioavailability from a CFF mixed with cereal porridge.

  18. Comparative in vitro studies on disodium EDTA effect with and without Proteus mirabilis on the crystallization of carbonate apatite and struvite

    NASA Astrophysics Data System (ADS)

    Prywer, Jolanta; Olszynski, Marcin; Torzewska, Agnieszka; Mielniczek-Brzóska, Ewa

    2014-06-01

    Effect of disodium EDTA (salt of ethylenediamine tetraacetic acid) on the crystallization of struvite and carbonate apatite was studied. To evaluate such an effect we performed an experiment of struvite and carbonate apatite growth from artificial urine. The crystallization process was induced by Proteus mirabilis to mimic the real urinary tract infection, which usually leads to urinary stone formation. The results demonstrate that disodium EDTA exhibits the effect against P. mirabilis retarding the activity of urease - an enzyme produced by these microorganisms. The spectrophotometric results demonstrate that, with and without P. mirabilis, the addition of disodium EDTA increases the induction time and decreases the growth efficiency compared to the baseline (without disodium EDTA). These results are discussed from the standpoint of speciation of complexes formed in the solution of artificial urine in the presence of disodium EDTA. The size of struvite crystals was found to decrease in the presence of disodium EDTA. However, struvite crystals are larger in the presence of bacteria while the crystal morphology and habit remain unchanged.

  19. 21 CFR 172.135 - Disodium EDTA.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 3 2012-04-01 2012-04-01 false Disodium EDTA. 172.135 Section 172.135 Food and... Preservatives § 172.135 Disodium EDTA. The food additive disodium EDTA (disodium ethylenediaminetetraace-tate... following foods at not to exceed the levels prescribed, calculated as anhydrous calcium disodium EDTA:...

  20. 21 CFR 172.135 - Disodium EDTA.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 3 2013-04-01 2013-04-01 false Disodium EDTA. 172.135 Section 172.135 Food and... Preservatives § 172.135 Disodium EDTA. The food additive disodium EDTA (disodium ethylenediaminetetraace-tate... following foods at not to exceed the levels prescribed, calculated as anhydrous calcium disodium EDTA:...

  1. Complexation and molecular modeling studies of europium(III)-gallic acid-amino acid complexes.

    PubMed

    Taha, Mohamed; Khan, Imran; Coutinho, João A P

    2016-04-01

    With many metal-based drugs extensively used today in the treatment of cancer, attention has focused on the development of new coordination compounds with antitumor activity with europium(III) complexes recently introduced as novel anticancer drugs. The aim of this work is to design new Eu(III) complexes with gallic acid, an antioxida'nt phenolic compound. Gallic acid was chosen because it shows anticancer activity without harming health cells. As antioxidant, it helps to protect human cells against oxidative damage that implicated in DNA damage, cancer, and accelerated cell aging. In this work, the formation of binary and ternary complexes of Eu(III) with gallic acid, primary ligand, and amino acids alanine, leucine, isoleucine, and tryptophan was studied by glass electrode potentiometry in aqueous solution containing 0.1M NaNO3 at (298.2 ± 0.1) K. Their overall stability constants were evaluated and the concentration distributions of the complex species in solution were calculated. The protonation constants of gallic acid and amino acids were also determined at our experimental conditions and compared with those predicted by using conductor-like screening model for realistic solvation (COSMO-RS) model. The geometries of Eu(III)-gallic acid complexes were characterized by the density functional theory (DFT). The spectroscopic UV-visible and photoluminescence measurements are carried out to confirm the formation of Eu(III)-gallic acid complexes in aqueous solutions.

  2. Serum albumin complexation of acetylsalicylic acid metabolites.

    PubMed

    Jurkowski, Wiktor; Porebski, Grzegorz; Obtułowicz, Krystyna; Roterman, Irena

    2009-06-01

    One possible origin of the type I hypersensitivity reaction is reaction of drugs such as acetylsalicylic acid and its metabolites being complexed with human serum albumin. Albumin, being transporting molecule abundant in blood plasma is able to bind large array of ligands varying from small single carbon particles to long hydrophobic tailed lipidic acids (e.g. myristic acid). This non specificity is possible because of multi domain scaffold and large flexibility of inter-domain loops, which results in serious reorientation of domains. Hypothesis that acetylsalicylic acid metabolites may play indirect role in activation of allergic reaction has been tested. Binding of acetylsalicylic acid metabolites in intra-domain space causes significant increase of liability of domains IIIA and IIIB. One of metabolites, salicyluric acid, once is bound causes distortion and partial unfolding of helices in domains IA, IIB and IIIB. Changed are both directions and amplitude of relative motions as well as intra-domain distances. In result albumin is able to cross-link of adjacent IgE receptors which subsequently starts allergic reaction.

  3. Serum albumin complexation of acetylsalicylic acid metabolites.

    PubMed

    Jurkowski, Wiktor; Porebski, Grzegorz; Obtułowicz, Krystyna; Roterman, Irena

    2009-06-01

    One possible origin of the type I hypersensitivity reaction is reaction of drugs such as acetylsalicylic acid and its metabolites being complexed with human serum albumin. Albumin, being transporting molecule abundant in blood plasma is able to bind large array of ligands varying from small single carbon particles to long hydrophobic tailed lipidic acids (e.g. myristic acid). This non specificity is possible because of multi domain scaffold and large flexibility of inter-domain loops, which results in serious reorientation of domains. Hypothesis that acetylsalicylic acid metabolites may play indirect role in activation of allergic reaction has been tested. Binding of acetylsalicylic acid metabolites in intra-domain space causes significant increase of liability of domains IIIA and IIIB. One of metabolites, salicyluric acid, once is bound causes distortion and partial unfolding of helices in domains IA, IIB and IIIB. Changed are both directions and amplitude of relative motions as well as intra-domain distances. In result albumin is able to cross-link of adjacent IgE receptors which subsequently starts allergic reaction. PMID:19689242

  4. Rational design, synthesis, and evaluation of tetrahydroxamic acid chelators for stable complexation of zirconium(IV).

    PubMed

    Guérard, François; Lee, Yong-Sok; Brechbiel, Martin W

    2014-05-01

    Metals of interest for biomedical applications often need to be complexed and associated in a stable manner with a targeting agent before use. Whereas the fundamentals of most transition-metal complexation processes have been thoroughly studied, the complexation of Zr(IV) has been somewhat neglected. This metal has received growing attention in recent years, especially in nuclear medicine, with the use of (89) Zr, which a β(+) -emitter with near ideal characteristics for cancer imaging. However, the best chelating agent known for this radionuclide is the trishydroxamate desferrioxamine B (DFB), the Zr(IV) complex of which exhibits suboptimal stability, resulting in the progressive release of (89) Zr in vivo. Based on a recent report demonstrating the higher thermodynamic stability of the tetrahydroxamate complexes of Zr(IV) compared with the trishydroxamate complexes analogues to DFB, we designed a series of tetrahydroxamic acids of varying geometries for improved complexation of this metal. Three macrocycles differing in their cavity size (28 to 36-membered rings) were synthesized by using a ring-closing metathesis strategy, as well as their acyclic analogues. A solution study with (89) Zr showed the complexation to be more effective with increasing cavity size. Evaluation of the kinetic inertness of these new complexes in ethylenediaminetetraacetic acid (EDTA) solution showed significantly improved stabilities of the larger chelates compared with (89) Zr-DFB, whereas the smaller complexes suffered from insufficient stabilities. These results were rationalized by a quantum chemical study. The lower stability of the smaller chelates was attributed to ring strain, whereas the better stability of the larger cyclic complexes was explained by the macrocyclic effect and by the structural rigidity. Overall, these new chelating agents open new perspectives for the safe and efficient use of (89) Zr in nuclear imaging, with the best chelators providing dramatically

  5. 21 CFR 172.315 - Nicotinamide-ascorbic acid complex.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 3 2014-04-01 2014-04-01 false Nicotinamide-ascorbic acid complex. 172.315... Nutritional Additives § 172.315 Nicotinamide-ascorbic acid complex. Nicotinamide-ascorbic acid complex may be... the controlled reaction between ascorbic acid and nicotinamide, melting in the range 141 °C to 145...

  6. Thermal Treatment of EDTA Solutions

    SciTech Connect

    Denne, B.

    2006-07-01

    Chemical cleaning of commercial nuclear power facility secondary systems, using EDTA, results in large volumes of chelated liquids requiring some form of treatment prior to disposal. The Nuclear Regulatory Commission regulates the presence of chelates in disposal cells and this paper will look at several methods used to ensure compliance with disposal site criteria. The emphasis of this paper will be on results achieved through thermal treatment of chemical cleaning wastes at the Pacific EcoSolutions' (PEcoS) low level and mixed radioactive waste processing facility in Richland, Washington. We will discuss challenges in transportation, receipt, storage, processing, and disposal associated with EDTA solutions and how those challenges are overcome. (author)

  7. Radiation effects on the dissolution kinetics of magnetite and hematite in EDTA- and NTA-based dilute chemical decontamination formulations

    NASA Astrophysics Data System (ADS)

    Keny, S. J.; Kumbhar, A. G.; Venkateswaran, G.; Kishore, Kamal

    2005-03-01

    Ethylene diamine tetraacetic acid (EDTA)- and nitrilo triacetic acid (NTA)-based formulations such as citric acid (CA)/EDTA/ascorbic acid (AA), CA/EDTA/gallic acid (GA), CA/NTA/AA and CA/NTA/GA were used for dissolving magnetite and hematite under similar experimental conditions of temperature, amount of the oxide and the concentration of the formulations (close to stoichiometric conditions). In unirradiated solutions, EDTA-based formulations were more efficient in dissolving these oxides than NTA-based formulations. Similarly, formulations containing AA as reductant gave better results as compared to formulations containing GA as reductant in unirradiated solutions. However, in gamma-irradiated formulations, the efficiency of dissolution was affected to a much greater extent in EDTA and AA containing formulations as compared to NTA and GA containing formulations. Both NTA and GA were found to be less prone to radiation degradation as compared to EDTA and AA.

  8. The role and fate of EDTA in ultrasound-enhanced zero-valent iron/air system.

    PubMed

    Zhou, Tao; Lim, Teik-Thye; Li, Yaozhong; Lu, Xiaohua; Wong, Fook-Sin

    2010-01-01

    In this study, factors such as ZVI loading, ultrasound (US) input power, reaction temperature and solution pH that could affect the EDTA degradation in the US-enhanced zero-valent iron/air (US/ZVI/air) system were investigated. In the system, EDTA also served as an agent for complexation with the dissolved Fe(2+) and producing H(2)O(2) that would trigger Fenton-like reaction and degrade the EDTA itself. US played a threefold role in enhancing the overall EDTA degradation rate through: (1) accelerating ZVI corrosion and production of Fe(2+); (2) enhancing H(2)O(2) production through overcoming the kinetic barrier of oxygen activation by iron-EDTA complex; (3) improving EDTA mineralization while reducing its harmful by-products. The EDTA degradation rate with the US/ZVI/air system was 7.8 times higher than the combined rates achieved with US/air and ZVI/air operated as individual systems, indicating a significant synergistic effect. A hypothetical scheme illustrating the role and fate of EDTA in the US/ZVI/air system is proposed, indicating a complex auto-oxidation process enhanced by the US. It is postulated that ferryl-EDTA complex ([Fe(IV)O]EDTA) rather than OH was the dominant oxidant generated in the US/ZVI/air system that oxidized the EDTA even under the circumneutral condition.

  9. A Laser-Pointer-Based Spectrometer for Endpoint Detection of EDTA Titrations

    ERIC Educational Resources Information Center

    Dahm, Christopher E.; Hall, James W.; Mattioni, Brian E.

    2004-01-01

    A laser spectrometer for the ethylenediaminetetra-acetic acid (EDTA) titration of magnesium or calcium ions that is designed around a handheld laser pointer as the source and a photoresistor as the detector is developed. Findings show that the use of the spectrometer reduces the degree of uncertainty and error in one part of the EDTA titrations,…

  10. Microwave structure for the propiolic acid-formic acid complex.

    PubMed

    Kukolich, Stephen G; Mitchell, Erik G; Carey, Spencer J; Sun, Ming; Sargus, Bryan A

    2013-10-01

    New microwave spectra were measured to obtain rotational constants and centrifugal distortion constants for the DCCCOOH···HOOCH and HCCCOOD···DOOCH isotopologues. Rotational transitions were measured in the frequency range of 4.9-15.4 GHz, providing accurate rotational constants, which, combined with previous rotational constants, allowed an improved structural fit for the propiolic acid-formic acid complex. The new structural fit yields reasonably accurate orientations for both the propiolic and formic acid monomers in the complex and more accurate structural parameters describing the hydrogen bonding. The structure is planar, with a positive inertial defect of Δ = 1.33 amu Å(2). The experimental structure exhibits a greater asymmetry for the two hydrogen bond lengths than was obtained from the ab initio mp2 calculations. The best-fit hydrogen bond lengths have an r(O1-H1···O4) of 1.64 Å and an r(O3-H2···O2) of 1.87 Å. The average of the two hydrogen bond lengths is r(av)(exp) = 1.76 Å, in good agreement with r(av)(theory) = 1.72 Å. The center of mass separation of the monomers is R(CM) = 3.864 Å. Other structural parameters from the least-squares fit using the experimental rotational constants are compared with theoretical values. The spectra were obtained using two different pulsed beam Fourier transform microwave spectrometers.

  11. 21 CFR 573.360 - Disodium EDTA.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 6 2010-04-01 2010-04-01 false Disodium EDTA. 573.360 Section 573.360 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) ANIMAL DRUGS... Listing § 573.360 Disodium EDTA. The food additive disodium EDTA (disodium ethylenediaminetetraace-...

  12. 21 CFR 573.360 - Disodium EDTA.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 6 2014-04-01 2014-04-01 false Disodium EDTA. 573.360 Section 573.360 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) ANIMAL DRUGS... Listing § 573.360 Disodium EDTA. The food additive disodium EDTA (disodium ethylenediaminetetraace-...

  13. 21 CFR 573.360 - Disodium EDTA.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 6 2012-04-01 2012-04-01 false Disodium EDTA. 573.360 Section 573.360 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) ANIMAL DRUGS... Listing § 573.360 Disodium EDTA. The food additive disodium EDTA (disodium ethylenediaminetetraace-...

  14. 21 CFR 573.360 - Disodium EDTA.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 6 2011-04-01 2011-04-01 false Disodium EDTA. 573.360 Section 573.360 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) ANIMAL DRUGS... Listing § 573.360 Disodium EDTA. The food additive disodium EDTA (disodium ethylenediaminetetraace-...

  15. 21 CFR 172.135 - Disodium EDTA.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 3 2014-04-01 2014-04-01 false Disodium EDTA. 172.135 Section 172.135 Food and... PERMITTED FOR DIRECT ADDITION TO FOOD FOR HUMAN CONSUMPTION Food Preservatives § 172.135 Disodium EDTA. The food additive disodium EDTA (disodium ethylenediaminetetraace-tate) may be safely used in...

  16. 21 CFR 573.360 - Disodium EDTA.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 6 2013-04-01 2013-04-01 false Disodium EDTA. 573.360 Section 573.360 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) ANIMAL DRUGS... Listing § 573.360 Disodium EDTA. The food additive disodium EDTA (disodium ethylenediaminetetraace-...

  17. 21 CFR 172.315 - Nicotinamide-ascorbic acid complex.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Nicotinamide-ascorbic acid complex. 172.315 Section... HUMAN CONSUMPTION Special Dietary and Nutritional Additives § 172.315 Nicotinamide-ascorbic acid complex. Nicotinamide-ascorbic acid complex may be safely used in accordance with the following prescribed...

  18. 21 CFR 172.315 - Nicotinamide-ascorbic acid complex.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 3 2013-04-01 2013-04-01 false Nicotinamide-ascorbic acid complex. 172.315... HUMAN CONSUMPTION Special Dietary and Nutritional Additives § 172.315 Nicotinamide-ascorbic acid complex. Nicotinamide-ascorbic acid complex may be safely used in accordance with the following prescribed...

  19. 21 CFR 172.315 - Nicotinamide-ascorbic acid complex.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 3 2012-04-01 2012-04-01 false Nicotinamide-ascorbic acid complex. 172.315... HUMAN CONSUMPTION Special Dietary and Nutritional Additives § 172.315 Nicotinamide-ascorbic acid complex. Nicotinamide-ascorbic acid complex may be safely used in accordance with the following prescribed...

  20. 21 CFR 172.315 - Nicotinamide-ascorbic acid complex.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 3 2011-04-01 2011-04-01 false Nicotinamide-ascorbic acid complex. 172.315... HUMAN CONSUMPTION Special Dietary and Nutritional Additives § 172.315 Nicotinamide-ascorbic acid complex. Nicotinamide-ascorbic acid complex may be safely used in accordance with the following prescribed...

  1. EnEnvironmental Mobility of Pu(IV) in the Presence of Ethylenediaminetetraacetic Acid: Myth or Reality

    SciTech Connect

    Rai, Dhanpat; Moore, Dean A.; Rosso, Kevin M.; Felmy, Andrew R.; Bolton, Harvey

    2008-07-01

    Ethylenediaminetetracetic acid (EDTA), which was co-disposed with Pu at several U. S. Department of Energy sites, has been reported to enhance the solubility and transport of Pu. It is generally assumed that this enhanced transport of Pu in geologic environments is a result of complexation of Pu(IV) with EDTA. However, the fundamental bases for this assumption have never been fully explored. Whether EDTA can mobilize Pu(IV) in geologic environments is dependent on many factors, chief among them are not only the complexation constants of Pu with EDTA and dominant oxidation state and the nature of Pu solids, but also 1) the complexation constants of environmentally important metal ions (e.g. Fe, Al, Ca, Mg) that compete with Pu for EDTA and 2) EDTA interactions with geomedia (e.g., adsorption, biodegradation) that reduce effective EDTA concentrations available for complexation. Extensive studies over a large range of pH values (1 to 14) and EDTA concentrations (0.0001 to 0.01 M) as a function of time were conducted on the solubility of 2-line ferrihydrite (Fe(OH)3(s)), PuO2(am) in the presence of different concentrations of Ca ions, and mixtures of PuO2(am) and Fe(OH)3(s). The solubility data were interpreted using Pitzer’s ion-interaction approach to determine/validate the solubility product of Fe(OH)3(s), the complexation constants of Pu(IV)-EDTA and Fe(III)-EDTA, and to determine the affect of EDTA in solubilizing Pu(IV) from PuO2(am) in the presence of Fe(III) compounds and aqueous Ca concentrations. Predictions based on these extensive fundamental data show that environmental mobility of Pu as a result of Pu(IV)-EDTA complexation as reported/implied in the literature is a myth rather than the reality.

  2. Outer-sphere adsorption of Pb(II)EDTA on goethite

    SciTech Connect

    Bargar, J.R.; Persson, P.; Brown, G.E. Jr.

    1999-10-01

    Fourier transform infrared (FTIR) and extended X-ray absorption fine structure (EXAPS) spectroscopic measurements were performed on Pb(II)ethylenediaminetetraacetic (EDTA) adsorbed on goethite as a function of pH (4--6), Pb(II)EDTA concentration (0.11--72 {micro}M), and ionic strength (16 {micro}M--0.5 M). FTIR measurements show no evidence for carboxylate-Fe(III) bonding or protonation of EDTA at Pb:EDTA = 1:1. Both FTIR and EXAFS spectroscopic measurements suggest that EDTA acts as a hexadentate ligand, with all four of its carboxylate and both of its amine groups bonded to Pb(II). No evidence was observed for inner-sphere Pb(II)-goethite bonding at Pb:EDTA = 1:1. Hence, the adsorbed complexes should have composition Pb(II)EDTA{sup 2{minus}}. Because substantial uptake of PbEDTA(II){sup 2{minus}} occurred in the samples, the authors interpret that Pb(II)EDTA{sup 2{minus}} adsorbed as outer-sphere complexes and/or as complexes that lose part of their solvation shells and hydrogen bond directly to goethite surface sites. The authors propose the term hydration-sphere for the latter type of complexes because they should occupy space in the primary hydration spheres of goethite surface functional groups and to distinguish this mode of sorption from common structural definitions of inner- and outer-sphere complexes. The lack of evidence for inner-sphere EDTA-Fe(III) bonding suggests that previously proposed metal/ligand-promoted dissolution mechanisms should be modified, specifically to account for the presence of outer-sphere precursor species.

  3. Behavior of carboxylic acids upon complexation with beryllium compounds.

    PubMed

    Mykolayivna-Lemishko, Kateryna; Montero-Campillo, M Merced; Mó, Otilia; Yáñez, Manuel

    2014-07-31

    A significant acidity enhancement and changes on aromaticity were previously observed in squaric acid and its derivatives when beryllium bonds are present in those systems. In order to know if these changes on the chemical properties could be considered a general behavior of carboxylic acids upon complexation with beryllium compounds, complexes between a set of representative carboxylic acids RCOOH (formic acid, acetic acid, propanoic acid, benzoic acid, and oxalic acid) and beryllium compounds BeX2 (X = H, F, Cl) were studied by means of density functional theory calculations. Complexes that contain a dihydrogen bond or a OH···X interaction are the most stable in comparison with other possible BeX2 complexation patterns in which no other weak interactions are involved apart from the beryllium bond. Formic, acetic, propanoic, benzoic, and oxalic acid complexes with BeX2 are much stronger acids than their related free forms. The analysis of the topology of the electron density helps to clarify the reasons behind this acidity enhancement. Importantly, when the halogen atom is replaced by hydrogen in the beryllium compound, the dihydrogen bond complex spontaneously generates a new neutral complex [RCOO:BeH] in which a hydrogen molecule is lost. This seems to be a trend for carboxylic acids on complexing BeX2 compounds.

  4. Wavelength Shifters and Interactions of EDTA with Acrylic & LAB

    NASA Astrophysics Data System (ADS)

    Mohan, Yuvraj; SNO+ Collaboration

    2014-09-01

    The SNO + experiment, an upgrade to the Sudbury Neutrino Observatory, will use linear alkyl-benzene (LAB) liquid scintillator to probe new physics, including 0 νββ decay. Event detection efficiency is heavily affected by radioactive backgrounds, two sources being Rn-222 and Po-210 daughters, some of which has become embedded in the SNO + acrylic vessel after years underground. The leading candidate for polonium leaching is Ethylenediaminetetraacetic acid (EDTA). Before deployment on-site, EDTA's effects on the mechanical integrity of acrylic must be determined. It also must not be soluble in LAB or must be removed before scintillator fill of the vessel, as its presence would result in reduced light yield due to scattering. It was found that EDTA had negligible effects on the Young's Modulus of acrylic. EDTA is also slightly soluble in LAB, but can be completely removed by rinsing with water. Additionally, the study of the light yield and alpha/beta timing profiles of two wavelength shifters - bisMSB and perylene - is critical to determining which should be added to the 0 νββ isotope (tellurium) LAB cocktail. Small-scale results hint that perylene might be better, but this is being confirmed with larger-scale tests. The SNO + experiment, an upgrade to the Sudbury Neutrino Observatory, will use linear alkyl-benzene (LAB) liquid scintillator to probe new physics, including 0 νββ decay. Event detection efficiency is heavily affected by radioactive backgrounds, two sources being Rn-222 and Po-210 daughters, some of which has become embedded in the SNO + acrylic vessel after years underground. The leading candidate for polonium leaching is Ethylenediaminetetraacetic acid (EDTA). Before deployment on-site, EDTA's effects on the mechanical integrity of acrylic must be determined. It also must not be soluble in LAB or must be removed before scintillator fill of the vessel, as its presence would result in reduced light yield due to scattering. It was found that EDTA

  5. EDTA: An Antimicrobial and Antibiofilm Agent for Use in Wound Care

    PubMed Central

    Finnegan, Simon; Percival, Steven L.

    2015-01-01

    Significance: Methods employed for preventing and eliminating biofilms are limited in their efficacy on mature biofilms. Despite this a number of antibiofilm formulations and technologies incorporating ethylenediaminetetraacetic acid (EDTA) have demonstrated efficacy on in vitro biofilms. The aim of this article is to critically review EDTA, in particular tetrasodium EDTA (tEDTA), as a potential antimicrobial and antibiofilm agent, in its own right, for use in skin and wound care. EDTA's synergism with other antimicrobials and surfactants will also be discussed. Recent Advances: The use of EDTA as a potentiating and sensitizing agent is not a new concept. However, currently the application of EDTA, specifically tEDTA as a stand-alone antimicrobial and antibiofilm agent, and its synergistic combination with other antimicrobials to make a “multi-pronged” approach to biofilm control is being explored. Critical Issues: As pathogenic biofilms in the wound increase infection risk, tEDTA could be considered as a potential “stand-alone” antimicrobial/antibiofilm agent or in combination with other antimicrobials, for use in both the prevention and treatment of biofilms found within abiotic (the wound dressing) and biotic (wound bed) environments. The ability of EDTA to chelate and potentiate the cell walls of bacteria and destabilize biofilms by sequestering calcium, magnesium, zinc, and iron makes it a suitable agent for use in the management of biofilms. Future Direction: tEDTA's excellent inherent antimicrobial and antibiofilm activity and proven synergistic and permeating ability results in a very beneficial agent, which could be used for the development of future antibiofilm technologies. PMID:26155384

  6. PuPO4(cr, hyd.) Solubility Product and Pu3+ Complexes With Phosphate and Ethylenediaminetetraacetic Acid

    SciTech Connect

    Rai, Dhanpat; Moore, Dean A.; Felmy, Andrew R.; Rosso, Kevin M.; Bolton, Harvey

    2010-06-15

    To determine the solubility product of PuPO4(cr, hyd.) and the complexation constants of Pu(III) with phosphate and EDTA, the solubility of PuPO4(cr, hyd.) was investigated as a function of: 1) time and pH varying from 1.0 to 12.0 and at a fixed 0.00032 M phosphate concentration; 2) NaH2PO4 concentrations varying from 0.0001 M to 1.0 M and at a fixed pH value of 2.5; 3) time and pH varying from 1.3 to 13.0 at fixed concentrations of 0.00032 M phosphate and 0.0004 M or 0.002 M Na2H2EDTA; and 4) Na2H2EDTA concentrations varying from 0.00005 M to 0.0256 M at a fixed 0.00032 M phosphate concentration and at pH values of approximately 3.5, 10.6, and 12.6. A combination of solvent extraction and spectrophotometric techniques confirmed that the use of hydroquinone and Na2S2O4 helped maintain Pu as Pu(III). The solubility data were interpreted using Pitzer and SIT models, and both provided similar values for the solubility product of PuPO4(cr, hyd.) and for the formation constant of PuEDTA-. The log10 of the solubility product of PuPO4(cr, hyd.) (PuPO4(cr, hyd.) = Pu3+ + PO4 ) was determined to be –(24.42 ± 0.38). Pitzer modeling showed that phosphate interactions with Pu3+ were extremely weak and did not require any phosphate complexes (e.g., PuPO4(aq), PuH2PO42+, Pu(H2PO4)2+, Pu(H2PO4)3(aq), and Pu(H2PO4)4-), as proposed in existing literature, to explain the experimental data. SIT modeling, however, required the inclusion of PuH2PO42+ to explain the data in high NaH2PO4 concentrations; this illustrates the differences one can expect when using these two chemical models to interpret the data. As the Pu(III)-EDTA species, only PuEDTA- was needed to interpret the experimental data in a large range in pH values (1.3–12.9) and EDTA concentrations (0.00005–0.256 M). Calculations based on density functional theory support the existence of PuEDTA- (with prospective stoichiometry as Pu(OH2)3EDTA-) as the chemically and structurally stable species. The log10 of the

  7. Batch affinity adsorption of His-tagged proteins with EDTA-based chitosan.

    PubMed

    Hua, Weiwei; Lou, Yimin; Xu, Weiyuan; Cheng, Zhixian; Gong, Xingwen; Huang, Jianying

    2016-01-01

    Affinity adsorption purification of hexahistidine-tagged (His-tagged) proteins using EDTA-chitosan-based adsorption was designed and carried out. Chitosan was elaborated with ethylenediaminetetraacetic acid (EDTA), and the resulting polymer was characterized by FTIR, TGA, and TEM. Different metals including Ni(2+), Cu(2+), and Zn(2+) were immobilized with EDTA-chitosan, and their capability to the specific adsorption of His-tagged proteins were then investigated. The results showed that Ni(2+)-EDTA-chitosan and Zn(2+)-EDTA-chitosan had high affinity toward the His-tagged proteins, thus isolating them from protein mixture. The target fluorescent-labeled hexahistidine protein remained its fluorescent characteristic throughout the purification procedure when Zn(2+)-EDTA-chitosan was used as a sorbent, wherein the real-time monitor was performed to examine the immigration of fluorescent-labeled His-tagged protein. Comparatively, Zn(2+)-EDTA-chitosan showed more specific binding ability for the target protein, but with less binding capacity. It was further proved that this purification system could be recovered and reused at least for 5 times and could run on large scales. The presented M(2+)-EDTA-chitosan system, with the capability to specifically bind His-tagged proteins, make the purification of His-tagged proteins easy to handle, leaving out fussy preliminary treatment, and with the possibility of continuous processing and a reduction in operational cost in relation to the costs of conventional processes.

  8. Photochemical properties of copper(II)-amino acid complexes

    SciTech Connect

    Natarajan, P.; Ferraudi, G.

    1981-11-01

    The photochemistry of copper(II)-amino acid complexes (amino acid = glutamic acid, ..beta..-alanine, or glycine) has been investigated by continuous and flash photolysis. The charge-transfer irradiations induce the oxidation of the ligand and the reduction of copper(II) to copper(I). Transients observed in flash photolysis have been assigned as copper-alkyl complexes. Moreover, other copper-alkyl species are produced when carbon-centered radicals react with excess of copper(II) complexes. The photochemical properties of the copper(II)-amino acid complexes are discussed in terms of population of charge transfer to copper excited states.

  9. N2O production in the Fe(II)(EDTA)-NO reduction process: the effects of carbon source and pH.

    PubMed

    Chen, Jun; Wang, Lei; Zheng, Ji; Chen, Jianmeng

    2015-07-01

    Chemical absorption-biological reduction (BioDeNOx), which uses Fe(II)(EDTA) as a complexing agent for promoting the mass transfer efficiency of NO from gas to water, is a promising technology for removing nitric oxide (NO) from flue gases. The carbon source and pH are important parameters for Fe(II)(EDTA)-NO (the production of absorption) reduction and N2O emissions from BioDeNOx systems. Batch tests were performed to evaluate the effects of four different carbon sources (i.e., methanol, ethanol, sodium acetate, and glucose) on Fe(II)(EDTA)-NO reduction and N2O emissions at an initial pH of 7.2 ± 0.2. The removal efficiency of Fe(II)(EDTA)-NO was 93.9%, with a theoretical rate of 0.77 mmol L(-1) h(-1) after 24 h of operation. The highest N2O production was 0.025 mmol L(-1) after 3 h when glucose was used as the carbon source. The capacities of the carbon sources to enhance the activity of the Fe(II)(EDTA)-NO reductase enzyme decreased in the following order based on the C/N ratio: glucose > ethanol > sodium acetate > methanol. Over the investigated pH range of 5.5-8.5, the Fe(II)(EDTA)-NO removal efficiency was highest at a pH of 7.5, with a theoretical rate of 0.88 mmol L(-1) h(-1). However, the N2O production was lowest at a pH of 8.5. The primary effect of pH on denitrification resulted from the inhibition of nosZ in acidic conditions.

  10. Equilibrium characteristics of tartrate and EDTA-based electroless copper deposition baths

    SciTech Connect

    Ramasubramanian, M.; Popov, B.N.; White, R.E.; Chen, K.S.

    1997-08-01

    Electroless deposition of copper is being used for a variety of applications, one of them being the development of seed metallic layers on non-metals, which are widely used in electronic circuitry. Solution equilibrium characteristics of two electroless copper baths containing EDTA and tartrate as the complexing agents were studied as functions of pH, chelating agent and metal ion concentrations. Equilibrium diagrams were constructed for both cu-tartrate and Cu-EDTA systems. It was determined that copper is chiefly complexed as Cu(OH){sub 2}L{sub 2}{sup {minus}4} in the tartrate bath, and as CuA{sup {minus}2} in the EDTA bath, where L and A are the complexing tartrate and EDTA ligands, respectively. The operating ranges for electroless copper deposition were identified for both baths. Dependence of Cu(OH){sub 2} precipitation on the pH and species concentrations was also studied for these systems.

  11. Chelant extraction of heavy metals from contaminated soils using new selective EDTA derivatives.

    PubMed

    Zhang, Tao; Liu, Jun-Min; Huang, Xiong-Fei; Xia, Bing; Su, Cheng-Yong; Luo, Guo-Fan; Xu, Yao-Wei; Wu, Ying-Xin; Mao, Zong-Wan; Qiu, Rong-Liang

    2013-11-15

    Soil washing is one of the few permanent treatment alternatives for removing metal contaminants. Ethylenediaminetetraacetic acid (EDTA) and its salts can substantially increase heavy metal removal from contaminated soils and have been extensively studied for soil washing. However, EDTA has a poor utilization ratio due to its low selectivity resulting from the competition between soil major cations and trace metal ions for chelation. The present study evaluated the potential for soil washing using EDTA and three of its derivatives: CDTA (trans-1,2-cyclohexanediaminetetraacetic acid), BDTA (benzyldiaminetetraacetic acid), and PDTA (phenyldiaminetetraacetic acid), which contain a cylcohexane ring, a benzyl group, and a phenyl group, respectively. Titration results showed that PDTA had the highest stability constants for Cu(2+) and Ni(2+) and the highest overall selectivity for trace metals over major cations. Equilibrium batch experiments were conducted to evaluate the efficacy of the EDTA derivatives at extracting Cu(2+), Zn(2+), Ni(2+), Pb(2+), Ca(2+), and Fe(3+) from a contaminated soil. At pH 7.0, PDTA extracted 1.5 times more Cu(2+) than did EDTA, but only 75% as much Ca(2+). Although CDTA was a strong chelator of heavy metal ions, its overall selectivity was lower and comparable to that of EDTA. BDTA was the least effective extractant because its stability constants with heavy metals were low. PDTA is potentially a practical washing agent for soils contaminated with trace metals.

  12. Anaerobic Biotransformation and Mobility of Pu and PuEDTA

    SciTech Connect

    Xun, Luying

    2005-06-01

    Although our goal is to isolate anaerobic EDTA degraders, we initiated the experiments to include nitrilotriacetate (NTA), which is a structure homologue of EDTA. All the aerobic EDTA degraders can degrade NTA, but the isolated NTA degraders cannot degrade EDTA. Since NTA is a simpler structure homologue, it is likely that EDTA-degrading ability is evolved from NTA degradation. This hypothesis is further supported from our characterization of EDTA and NTA-degrading enzymes and genes (J. Bact. 179:1112-1116; and Appl. Environ. Microbiol. 67:688-695). The EDTA monooxygenase and NTA monooxygenase are highly homologous. EDTA monooxygenase can use both EDTA and NTA as substrates, but NTA monooxygenase can only use NTA as a substrate. Thus, we put our effort to isolate both NTA and EDTA degraders. In case, an anaerobic EDTA degrader is not immediately enriched, we will try to evolve the NTA degraders to use EDTA. Both aerobic and anaerobic enrichment cultures were set.

  13. Enhanced phytoextraction of Cu, Pb, Zn and Cd with EDTA and EDDS.

    PubMed

    Luo, Chunling; Shen, Zhenguo; Li, Xiangdong

    2005-03-01

    Chemically enhanced phytoextraction has been proposed as an effective approach to removing heavy metals from contaminated soil through the use of high biomass plants. Using pot experiments, the effects of the application of EDTA, EDDS and citric acid on the uptake of Cu, Pb, Zn and Cd by corn (Zea mays L. cv. Nongda 108) and bean (Phaseolus vulgaris L. white bean) plants were studied. The results showed that EDDS was more effective than EDTA at increasing the concentration of Cu in corn and beans. The application of 5 mmol kg-1 soil EDDS to soil significantly increased concentrations of Cu in shoots, with maximum levels of 2060 and 5130 mg kg-1 DW in corn and beans, respectively, which were 45- and 135-fold higher than that in the corresponding control plants to which chelate had not been applied. Concentrations of Zn in shoots were also higher in the plants treated with EDDS than in those treated with EDTA. For Pb and Cd, EDDS was less effective than EDTA. The maximum Cu phytoextraction was found with the EDDS treatment. The application of EDTA and EDDS also significantly increased the shoot-to-root ratios of the concentrations of Cu, Pb, Zn and Cd in both plant species. The results of metal extraction with chelates showed that EDDS was more efficient at solubilizing Cu and Zn than EDTA, and that EDTA was better at solubilizing Pb and Cd than EDDS.

  14. Enhanced ALP activity of MG63 cells cultured on hydroxyapatite-poly(ethylene glycol) hydrogel composites prepared using EDTA-OH.

    PubMed

    Ito, Temmei; Sasaki, Makoto; Taguchi, Tetsushi

    2015-03-02

    In order to obtain a hydroxyapatite (HAp)-poly(ethylene glycol) (PEG) composite, tetra amine-terminated PEG was crosslinked using disuccinimidyl tartrate to obtain a PEG hydrogel. Using two kinds of chelators with different stability constants for Ca ion (N-(2-hydroxyethyl) ethylenediamine-N,N',N'-triacetic acid (EDTA-OH, 8.14), and ethylenediamine-N,N,N',N'-tetraacetic acid (EDTA, 10.96)), calcium phosphate was deposited within PEG hydrogels by heating the chelator-containing calcium phosphate solution at 90 °C. X-ray diffraction analysis showed that the deposited calcium phosphate was HAp. The crystallinity of the HAp deposited using EDTA-OH was low compared with that obtained using EDTA, but the amount of HAp deposited within the PEG hydrogel using EDTA-OH was higher than that deposited using EDTA. Significantly more human osteoblast-like MG-63 cells adhered on the HAp-PEG composite prepared using EDTA-OH than on the HAp-PEG composites prepared using EDTA. Furthermore, the alkaline phosphatase activity of MG-63 cultured on the HAp-PEG composite prepared using EDTA-OH was four times higher than that on the HAp-PEG composite prepared using EDTA. Therefore, the HAp-PEG composite prepared using EDTA-OH has potential as a bone substitute material.

  15. Decomposition of peracetic acid catalyzed by vanadium complexes

    SciTech Connect

    Makarov, A.P.; Gekhman, A.E.; Moiseev, I.I.; Polotryuk, O.Y.

    1986-02-01

    This paper studies the decomposition of peracetic acid (AcOOH) in acetic acid (AcOH) catalyzed by vanadium complexes. It is shown that peractic acid in acetic acid solutions of ammonium anadate decomposes with the predominant formation of 0/sub 2/ and small amounts of CO/sub 2/, the yield of which increases with increasing temperature and peracetic acid concentration. Both reactions proceed without the formation of free radicals in amounts detectable by ESR spectroscopy. The rate of oxygen release under conditions in which the formation of CO/sub 2/ is insignificant obeys a kinetic equation indicating the intermediate formation of a complex between V/sup 5 +/ ions and peracetic acid and the slow conversion of this complex into the observed products.

  16. Effect of pH on the destruction of complexants with ozone in Hanford nuclear waste

    SciTech Connect

    Winters, W.I.

    1981-06-01

    Chemical processing of nuclear waste at Hanford has generated some waste solutions with high concentration (0.1 to 0.5M) of N-(hydroxyethyl)-ethylenediaminetriacetic acid (HEDTA), ethylenediaminetetraacetic acid (EDTA), and other organic complexing agents. These complexants must be destroyed bacause they affect radionuclide migration in soils, waste concentration, radionuclide removal, and other waste storage and processing considerations. Previous studies on actual waste solutions demonstrated that preozonation of the alkaline waste significantly improved radionuclide removal. A series of bench-scale experiments using synthetic waste has been performed to determine the optimum pH for most efficient ozone destruction of EDTA. Ozonation of EDTA in synthetic waste was carried out over the pH range of 1 to 14. Potential catalytic materials were examined at different pH levels. The EDTA-ozone reaction rates and stoichiometric requirements were compared and evaluated for the varying conditions.

  17. Inhibition on Candida albicans biofilm formation using divalent cation chelators (EDTA).

    PubMed

    Ramage, Gordon; Wickes, Brian L; López-Ribot, José L

    2007-12-01

    Candida albicans can readily form biofilms on both inanimate and biological surfaces. In this study we investigated a means of inhibiting biofilm formation using EDTA (Ethylenediaminetetra-acetic acid), a divalent cation chelating agent, which has been shown to affect C. albicans filamentation. Candida albicans biofilms were formed in 96-well microtitre plates. Cells were allowed to adhere for 1, 2, and 4 h at 37 degrees C, washed in PBS, and then treated with different concentrations of EDTA (0, 2.5, 25, and 250 mM). EDTA was also added to the standardized suspension prior to adding to the microtiter plate and to a preformed 24 h biofilm. All plates were then incubated at 37 degrees C for an additional 24 h to allow for biofilm formation. The extent and characteristics of biofilm formation were then microscopically assessed and with a semi-quantitative colorimetric technique based on the use of an XTT-reduction assay. Northern blot analysis of the hyphal wall protein (HWP1) expression was also monitored in planktonic and biofilm cells treated with EDTA. Microscopic analysis and colorimetric readings revealed that filamentation and biofilm formation were inhibited by EDTA in a concentration dependent manner. However, preformed biofilms were minimally affected by EDTA (maximum of 31% reduction at 250 mM). The HWP1 gene expression was reduced in EDTA-treated planktonic and biofilm samples. These results indicate that EDTA inhibits C. albicans biofilm formation are most likely through its inhibitory effect on filamentation and indicates the potential therapeutic effects of EDTA. This compound may serve a non-toxic means of preventing biofilm formation on infections with a C. albicans biofilm etiology. PMID:17909983

  18. Synthesis and photochromic properties of EDTA-induced MoO{sub 3} powder

    SciTech Connect

    Yan, Minyan; Shen, Yi; Zhao, Li; Li, Zhen

    2011-10-15

    Graphical abstract: The MoO{sub 3} powder, which exhibits highly dispersed floral aggregated-like structure built up by superimposed and staggered nanoflakes with a diameter of 1-1.5 {mu}m and a thickness of 0.1-0.2 {mu}m, has been successfully obtained when the molar ratio of EDTA/Mo{sup 6+} is 0.05:1. The EDTA inducer obviously enlarges the surface area and apparently enhances the reactivity of MoO{sub 3} powders, making it show greater absorptive capacity to the excitation light and better photochromic properties than the pure MoO{sub 3} powder. Highlights: {yields} EDTA as organic inducing agent. {yields} EDTA inducer at EDTA/Mo{sup 6+} molar ratio of 0.05:1 enables growth of flower-like microspheres. {yields} The formation of flower-like MoO{sub 3} makes its photochromic properties strongly enhanced. -- Abstract: In this study, the photochromic MoO{sub 3} powder with novel morphology has been synthesized via hydrothermal method, using ethylene diamine tetraacetice acid (EDTA) as organic inducing agent. The influence of EDTA on the morphology, structure and photochromic properties of MoO{sub 3} powder has been characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), as well as ultraviolet and visible spectroscopy (UV-vis) and color difference meter. When the molar ratio of EDTA/Mo{sup 6+} is 0.05:1, the EDTA-induced MoO{sub 3} powder is found to have 3D flower-like morphologies and excellent photochromic properties. Furthermore, the possible growth mechanism of the flower-like structure and the photochromic mechanism of MoO{sub 3} powder are also discussed in detail.

  19. Humic Acid Complexation of Th, Hf and Zr in Ligand Competition Experiments: Metal Loading and Ph Effects

    NASA Technical Reports Server (NTRS)

    Stern, Jennifer C.; Foustoukos, Dionysis I.; Sonke, Jeroen E.; Salters, Vincent J. M.

    2014-01-01

    The mobility of metals in soils and subsurface aquifers is strongly affected by sorption and complexation with dissolved organic matter, oxyhydroxides, clay minerals, and inorganic ligands. Humic substances (HS) are organic macromolecules with functional groups that have a strong affinity for binding metals, such as actinides. Thorium, often studied as an analog for tetravalent actinides, has also been shown to strongly associate with dissolved and colloidal HS in natural waters. The effects of HS on the mobilization dynamics of actinides are of particular interest in risk assessment of nuclear waste repositories. Here, we present conditional equilibrium binding constants (Kc, MHA) of thorium, hafnium, and zirconium-humic acid complexes from ligand competition experiments using capillary electrophoresis coupled with ICP-MS (CE- ICP-MS). Equilibrium dialysis ligand exchange (EDLE) experiments using size exclusion via a 1000 Damembrane were also performed to validate the CE-ICP-MS analysis. Experiments were performed at pH 3.5-7 with solutions containing one tetravalent metal (Th, Hf, or Zr), Elliot soil humic acid (EHA) or Pahokee peat humic acid (PHA), and EDTA. CE-ICP-MS and EDLE experiments yielded nearly identical binding constants for the metal- humic acid complexes, indicating that both methods are appropriate for examining metal speciation at conditions lower than neutral pH. We find that tetravalent metals form strong complexes with humic acids, with Kc, MHA several orders of magnitude above REE-humic complexes. Experiments were conducted at a range of dissolved HA concentrations to examine the effect of [HA]/[Th] molar ratio on Kc, MHA. At low metal loading conditions (i.e. elevated [HA]/[Th] ratios) the ThHA binding constant reached values that were not affected by the relative abundance of humic acid and thorium. The importance of [HA]/[Th] molar ratios on constraining the equilibrium of MHA complexation is apparent when our estimated Kc, MHA values

  20. Uptake and excretion of cadmium, cdEDTA, and zinc by Macoma balthica

    SciTech Connect

    McLeese, D.W.; Ray, S.

    1984-01-01

    The accumulation of cadmium from sea water by marine invertebrates has been studied. Chelation of Cd with ethylenediaminetetraacetic acid (EDTA) was reported to double the rate of Cd uptake and the final tissue concentration in mussels. The physicochemical properties of Cd and Zn are similar and it has been suggested that the two elements are biologically antagonistic. When both Cd and Zn are present, the level of Cd is reduced in polychaete worms and bivalve molluscs. In contrast, the level of Cd remained fairly constant for most tissues of P. montagui exposed to Cd at a constant level and to Zn at different levels. Because of the contrasting results concerning the effects of Cd and Zn combined, and of chelated Cd, this study was undertaken to determine if exposure to Cd and Zn in combination affects uptake and excretion of either element by the deposit-feeding mollusc, Macoma balthica. In addition, the effects of Cd complexed with EDTA and the chemical form of Cd on uptake of Cd in M. Balthica were examined.

  1. Ecological Risk Assessment of EDTA-Assisted Phytoremediation of Cd Under Different Cultivation Systems.

    PubMed

    Luo, Jie; Qi, Shihua; Gu, X W Sophie; Hou, Tao; Lin, Lihong

    2016-02-01

    A long-term field experiment was designed to assess remediation efficiency and ecological risk of phytoremediation of Cd under different cultivation systems with or without ethylene diamine tetraacetic acid (EDTA). EDTA can significantly improve the phytoremediation effectiveness of a historically polluted e-waste dismantling site through enhancing Cd uptake by plants in all cultivation systems along with higher ecological risks to different receptors especially in the presence of Cicer arietinum (chickpea). Moisture content at each layer of soil profile under Eucalyptus globules L. cultivated sites was consistently lower than under chickpea monoculture as a result of E. globules' high water use efficiency. Besides low soil moisture, E. globules can intercept more Cd-rich leachate than chickpea regardless of the presence of EDTA. E. globules could be used for Cd phytoremediation as they can take full advantage of EDTA and decrease ecological risk caused by the chelator.

  2. Complex formation between benzene carboxylic acids and β-cyclodextrin

    NASA Astrophysics Data System (ADS)

    Belyakova, L. A.; Lyashenko, D. Yu.

    2008-05-01

    Complex formation between benzene carboxylic acids and β-cyclodextrin in aqueous solutions at 290 300 K was studied using UV spectroscopy. The formation of 1:1 supramolecular inclusion compounds β-cyclodextrin-benzene and β-cyclodextrin-salicylic acid was found. Stability constants (Ks) of the complexes and thermodynamic parameters for formation of the inclusion compounds (ΔG, ΔH, and ΔS) were calculated.

  3. Chitosan-EDTA new combination is a promising candidate for treatment of bacterial and fungal infections.

    PubMed

    El-Sharif, Amany A; Hussain, Mohamed H M

    2011-03-01

    Chitosan is an attractive preparation widely used as a pharmaceutical excipient. This study aimed to evaluate the antimicrobial activities of chitosan derivatives, EDTA, and the newly developed chitosan-EDTA combination against Gram-negative and Gram-positive bacteria as well as Candida albicans. Antimicrobial activity was studied. Both minimal Inhibitory Concentrations (MIC) and minimal biocidal concentrations (MBC) were determined. Chitosan acetic acid recorded lower MIC values against Enterococcus faecalis, Escherichia coli, Staphylococcus aureus, Pseudomonas aeruginosa, and Candida albicans than those exhibited by EDTA. EDTA failed to have inhibitory activity against Enterococcus faecalis as well as MBC against any of the studied microorganisms. Chitosan acetic acid's MBC were recorded to all examined species. Checkerboard assay results indicated a synergistic antimicrobial activity of the new combination against Staphylococcus aureus and an additive effect against other microorganisms. Moreover, a short microbial exposure to chitosan-EDTA (20-30 min) caused complete eradication. Due to the continuous emergence of resistant strains, there is an urgent need to discover new antimicrobial agents. Our findings suggest the use of chitosan as an enhancing agent with antibacterial and antifungal properties in combination with EDTA in pharmaceutical preparations. PMID:20963418

  4. β-Cyclodextrin- para-aminosalicylic acid inclusion complexes

    NASA Astrophysics Data System (ADS)

    Roik, N. V.; Belyakova, L. A.; Oranskaya, E. I.

    2010-11-01

    Complex formation of β-cyclodextrin with para-aminosalicylic acid in buffer solutions is studied by UV spectroscopy. It is found that the stoichiometric proportion of the components in the β-cyclodextrin-para-aminosalicylic acid inclusion complex is 1:1. The Ketelar equation is used to calculate the stability constants of the inclusion complexes at different temperatures. The thermodynamic parameters of the complex formation process (ΔG, ΔH, ΔS) are calculated using the van't Hoff equation. The 1:1 β-cyclodextrin-para-aminosalicylic acid inclusion complex is prepared in solid form and its characteristics are determined by IR spectroscopic and x-ray diffraction techniques.

  5. 21 CFR 172.120 - Calcium disodium EDTA.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 3 2012-04-01 2012-04-01 false Calcium disodium EDTA. 172.120 Section 172.120... CONSUMPTION Food Preservatives § 172.120 Calcium disodium EDTA. The food additive calcium disodium EDTA... EDTA (disodium ethylenediaminetetraacetate) in the following foods at not to exceed, in...

  6. 21 CFR 172.120 - Calcium disodium EDTA.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 3 2014-04-01 2014-04-01 false Calcium disodium EDTA. 172.120 Section 172.120... disodium EDTA. The food additive calcium disodium EDTA (calcium disodium ethylene-diaminetetraacetate) may.... 1 By weight of egg yolk portion. (2) With disodium EDTA (disodium ethylenediaminetetraacetate)...

  7. 21 CFR 172.120 - Calcium disodium EDTA.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 3 2013-04-01 2013-04-01 false Calcium disodium EDTA. 172.120 Section 172.120... CONSUMPTION Food Preservatives § 172.120 Calcium disodium EDTA. The food additive calcium disodium EDTA... EDTA (disodium ethylenediaminetetraacetate) in the following foods at not to exceed, in...

  8. Enhanced photocatalytic activity of chromium(VI) reduction and EDTA oxidization by photoelectrocatalysis combining cationic exchange membrane processes.

    PubMed

    Hsu, Hung-Te; Chen, Shiao-Shing; Tang, Yi-Fang; Hsi, Hsing-Cheng

    2013-03-15

    A novel technology of photoelectrocatalysis (PEC) combining with cationic exchange membrane (CEM) was proposed for simultaneous reduction of chromium(VI) and oxidization of EDTA. The application of CEM was used to enhance the efficiency for prevention of the re-oxidation of reduced chromium with the electron-hole pairs. In this study, effects of current density, pH, TiO2 dosage, hydraulic retention time (HRT), light intensity and EDTA/Cr(VI) molar ratio were all investigated. The results showed that the optimum conversion efficiency occurred at 4mA/cm(2) with the presence of CEM. Higher conversion efficiencies were observed at lower pH due to the electrostatic attractions between positive charged TiOH2(+), and negatively charged Cr(VI) and EDTA. The optimum TiO2 loading of 1g/L was depended mainly on the acidic pH range, especially at higher HRT and irradiation intensity. In addition, higher EDTA/Cr(VI) molar ratio enhanced the reduction efficiency of Cr(VI), indicating EDTA plays the role of hole scavenger in this system. Moreover, incomplete EDTA decomposition contributes to the occurrence of intermediates, including nitrilotriacetic acid, iminodiacetic acid, glycine, oxamic acid, lyoxylic acid, oxalic acid, acetic acid and formic acid, as identified by GC/MS. Consequently, transformation pathway was determined from these analyzed byproducts and molecular orbital package analysis.

  9. Complex compound polyvinyl alcohol-titanic acid/titanium dioxide

    NASA Astrophysics Data System (ADS)

    Prosanov, I. Yu.

    2013-02-01

    A complex compound polyvinyl alcohol-titanic acid has been produced and investigated by means of IR and Raman spectroscopy, X-ray diffraction, and synchronous thermal analysis. It is claimed that it represents an interpolymeric complex of polyvinyl alcohol and hydrated titanium oxide.

  10. Comparison of EDTA and EDDS as potential soil amendments for enhanced phytoextraction of heavy metals.

    PubMed

    Meers, E; Ruttens, A; Hopgood, M J; Samson, D; Tack, F M G

    2005-02-01

    Phytoextraction has been proposed as an alternative remediation technology for soils polluted with heavy metals or radionuclides, but is generally conceived as too slow working. Enhancing the accumulation of trace pollutants in harvestable plant tissues is a prerequisite for the technology to be practically applicable. The chelating aminopolycarboxylic acid, ethylene diamine tetraacetate (EDTA), has been found to enhance shoot accumulation of heavy metals. However, the use of EDTA in phytoextraction may not be suitable due to its high environmental persistence, which may lead to groundwater contamination. This paper aims to assess whether ethylene diamine disuccinate (EDDS), a biodegradable chelator, can be used for enhanced phytoextraction purposes. A laboratory experiment was conducted to examine mobilisation of Cd, Cu, Cr, Ni, Pb and Zn into the soil solution upon application of EDTA or EDDS. The longevity of the induced mobilisation was monitored for a period of 40 days after application. Estimated effect half lives ranged between 3.8 and 7.5 days for EDDS, depending on the applied dose. The minimum observed effect half life of EDTA was 36 days, while for the highest applied dose no decrease was observed throughout the 40 day period of the mobilisation experiment. Performance of EDTA and EDDS for phytoextraction was evaluated by application to Helianthus annuus. Two other potential chelators, known for their biodegradability in comparison to EDTA, were tested in the plant experiment: nitrilo acetic acid (NTA) and citric acid. Uptake of heavy metals was higher in EDDS-treated pots than in EDTA-treated pots. The effects were still considered insufficiently high to consider efficient remediation. This may be partly due to the choice of timing for application of the soil amendment. Fixing the time of application at an earlier point before harvest may yield better results. NTA and citric acid induced no significant effects on heavy metal uptake.

  11. Geometry and cooperativity effects in adenosine-carboxylic acid complexes.

    PubMed

    Schlund, Sebastian; Mladenovic, Milena; Basílio Janke, Eline M; Engels, Bernd; Weisz, Klaus

    2005-11-23

    NMR experiments and theoretical investigations were performed on hydrogen bonded complexes of specifically 1- and 7-15N-labeled adenine nucleosides with carboxylic acids. By employing a freonic solvent of CDClF2 and CDF3, NMR spectra were acquired at temperatures as low as 123 K, where the regime of slow hydrogen bond exchange is reached and several higher-order complexes were found to coexist in solution. Unlike acetic acid, chloroacetic acid forms Watson-Crick complexes with the proton largely displaced from oxygen to the nitrogen acceptor in an ion pairing structure. Calculated geometries and chemical shifts of the proton in the hydrogen bridge favorably agree with experimentally determined values if vibrational averaging and solvent effects are taken into account. The results indicate that binding a second acidic ligand at the adenine Hoogsteen site in a ternary complex weakens the hydrogen bond to the Watson-Crick bound carboxylic acid. However, substituting a second adenine nucleobase for a carboxylic acid in the trimolecular complex leads to cooperative binding at Watson-Crick and Hoogsteen faces of adenosine.

  12. Enhanced photoelectrocatalytic decomposition of copper cyanide complexes and simultaneous recovery of copper with a Bi2MoO6 electrode under visible light by EDTA/K4P2O7.

    PubMed

    Zhao, Xu; Zhang, Juanjuan; Qiao, Meng; Liu, Huijuan; Qu, Jiuhui

    2015-04-01

    Simultaneous photoelectrocatalytic (PEC) oxidation of cyanides and recovery of copper in a PEC reactor with a Bi(2)MoO(6) photoanode was investigated at alkaline conditions under visible light irradiation. The surface variation of the Bi(2)MoO(6) photoanode and titanium cathode was characterized. The Cu mass distribution onto the anode, in the solution, and onto the cathode was fully investigated. In the individual PEC oxidation of copper cyanides, the formation of a black copper oxide on the anode occurred. By keeping the initial cyanide concentration at 0.01 mM, the effect of EDTA/K(4)P(2)O(7) was examined at different molar ratios of EDTA/K(4)P(2)O(7) to cyanide. It was indicated that the oxidation of cyanides increased and simultaneous copper electrodeposition with zero value onto the cathode was feasible at pH 11. Under the optimal conditions, the total cyanide concentration was lowered from 250 to 5.0 mg/L, and the Cu recovery efficiency deposited onto the cathode was higher than 90%. Cyanate was the only product. The role of the photogenerated hole in the oxidation of cyanide ions was confirmed. PMID:25768934

  13. Enhanced photoelectrocatalytic decomposition of copper cyanide complexes and simultaneous recovery of copper with a Bi2MoO6 electrode under visible light by EDTA/K4P2O7.

    PubMed

    Zhao, Xu; Zhang, Juanjuan; Qiao, Meng; Liu, Huijuan; Qu, Jiuhui

    2015-04-01

    Simultaneous photoelectrocatalytic (PEC) oxidation of cyanides and recovery of copper in a PEC reactor with a Bi(2)MoO(6) photoanode was investigated at alkaline conditions under visible light irradiation. The surface variation of the Bi(2)MoO(6) photoanode and titanium cathode was characterized. The Cu mass distribution onto the anode, in the solution, and onto the cathode was fully investigated. In the individual PEC oxidation of copper cyanides, the formation of a black copper oxide on the anode occurred. By keeping the initial cyanide concentration at 0.01 mM, the effect of EDTA/K(4)P(2)O(7) was examined at different molar ratios of EDTA/K(4)P(2)O(7) to cyanide. It was indicated that the oxidation of cyanides increased and simultaneous copper electrodeposition with zero value onto the cathode was feasible at pH 11. Under the optimal conditions, the total cyanide concentration was lowered from 250 to 5.0 mg/L, and the Cu recovery efficiency deposited onto the cathode was higher than 90%. Cyanate was the only product. The role of the photogenerated hole in the oxidation of cyanide ions was confirmed.

  14. Changes in haematology measurements with the Sysmex XT-2000iV during storage of feline blood sampled in EDTA or EDTA plus CTAD.

    PubMed

    Granat, Fanny; Geffré, Anne; Bourgès-Abella, Nathalie; Braun, Jean-Pierre; Trumel, Catherine

    2013-06-01

    In veterinary medicine a complete blood cell count (CBC) cannot always be performed within 24 h as usually recommended, particularly for specimens shipped to a reference laboratory. This raises the question of the stability of the variables, especially in ethylenediamine tetra-acetic acid (EDTA) feline blood specimens, known to be prone to in vitro platelet aggregation. Citrate, theophylline, adenosine and dipyridamole (CTAD) has been reported to limit platelet aggregation in feline blood specimens. The aim of this study was to measure the stability of the haematological variables and the platelet aggregation score in EDTA and EDTA plus CTAD (EDCT) feline blood specimens during 48 h of storage at room temperature. Forty-six feline EDTA and EDCT blood specimens were analysed with a Sysmex XT-2000iV analyser, and the platelet count and score of platelet aggregation were estimated immediately and after 24 and 48 h of storage. A significant increase in mean corpuscular volume, haematocrit, reticulocyte and eosinophil counts, and a significant decrease in mean corpuscular haemoglobin concentration and monocyte count were observed. Haemoglobin, mean corpuscular haemoglobin, and red blood cell, white blood cell, neutrophil and lymphocyte counts remained stable. Changes in reticulocyte indexes with time (low fluorescence ratio, medium fluorescence ratio, high fluorescence ratio and immature reticulocyte fraction) were not significant. Changes were generally more pronounced in EDTA than in EDCT. Platelet aggregation decreased markedly in initially highly aggregated EDTA specimens, and increased slightly in initially non- or mildly-aggregated EDTA or EDCT specimens. Platelet counts increased and decreased, or remained stable, respectively. CTAD can reduce storage-induced changes of the haematological variables in feline samples, thus improving the reliability of a CBC and limiting clinical misinterpretations.

  15. Degradation of the ferric chelate of EDTA by a pure culture of an Agrobacterium sp

    SciTech Connect

    Lauff, J.J.; Coogan, L.A.; Breitfeller, J.M. ); Steele, D.B. )

    1990-11-01

    A pure culture of an Agrobacterium sp. (deposited as ATCC 55002) the mineralizes the ferric chelate of EDTA (ferric-EDTA) was isolated by selective enrichment from a treatment facility receiving industrial waste containing ferric-EDTA. The isolated grew on ferric-EDTA as the sole carbon source at concentrations exceeding 100 mM. As the degradation proceeded, carbon dioxide, ammonia, and an unidentified metabolite(s) were produced; the pH increased, and iron was precipitated from solution. The maximum rate of degradation observed with sodium ferric-EDTA as the substrate was 24 mM/day. At a substrate concentration of 35 mM, 90% of the substrate was degraded in 3 days and 70% of the associated chemical oxygen demand was removed from solution. Less than 15% of the carbon initially present was incorporated into the cell mass. Significant growth of this strain was not observed with uncomplexed EDTA as the sole carbon source at comparable concentrations; however, the ferric chelate of propylenediaminetetraacetic acid (ferric-PDTA) did support growth.

  16. Quantifying the influence of EDTA on polymer nanoparticle deposition and retention in an iron-oxide-coated sand column.

    PubMed

    Yang, Xinyao; Liang, Dongxu; Deng, Shihuai

    2012-09-01

    Ethylenediaminotetraacetic acid (EDTA) occurring in groundwater aquifers complicates the prediction of nanoparticle movement in the porous medium. This paper demonstrates an approach combining Triple Pulse Experiments (TPEs) and numerical modelling to quantify the influence of EDTA on the deposition and retention of polymer nanoparticles in a water-saturated column packed with iron-oxide-coated sand. TPEs injecting three successive pulses in the order of nanoparticle, EDTA, nanoparticle permit nanoparticle deposition in the absence and the presence of EDTA to be compared. Random Sequential Adsorption (RSA) modelling of the nanoparticle breakthrough curves combining mass balance calculation allows the influence of EDTA to be quantified. TPE results demonstrate that the injected EDTA eluted the oxide coatings (favorable deposition sites) from the sand surface and the resulting decline in sites led to enhanced nanoparticle mobility in the subsequent pulse. Quantification results suggest that at the experimental time-scale and under the controlled conditions, elution of one deposition site requires injection of 2.4 × 10(11) EDTA molecules. In total, 75 gram EDTA needs to be injected to remove all the column sites.

  17. Oxidation of aqueous EDTA and associated organics and coprecipitation of inorganics by ambient iron-mediated aeration.

    PubMed

    Englehardt, James D; Meeroff, Daniel E; Echegoyen, Luis; Deng, Yang; Raymo, Françisco M; Shibata, Tomoyuki

    2007-01-01

    Cationic metal and radionuclide contaminants can be extracted from soils to groundwater with sequestering agents such as EDTA. However, EDTA must then be removed fromthe groundwater, by advanced oxidation or specialized biological treatment. In this work, aqueous individual metal-EDTA solutions were aerated with steel wool for 25 h, at ambient pH, temperature, and pressure. Removal of approximately 99% of EDTA (0.09-1.78 mM); glyoxylic acid (0.153 mM); chelated Cd2+ (0.94 and 0.0952 mM), Pb2+ (0.0502 mM), and Hg2+ (0.0419 mM); and free chromate and vanadate was shown. EDTA was oxidized to glyoxylic acid and formaldehyde, and metals/metalloids were coprecipitated together with iron oxyhydroxide floc. Free arsenite and arsenate were each removed at 99.97%. Free Sr2+, and chelated Ni2+ were removed at 92% and 63%, respectively. Similar removals were obtained from mixtures, including 99.996+/-0.004% removal of total arsenic (95% confidence). Traces of iminodiacetic acid, nitrilotriacetic acid, and ethylenediaminetriacetic acid were detected after 25 h. Results are consistent with first-order, solution-phase oxidation of EDTA and glyoxylic acid by ferryl ion and H202, respectively, with inhibition due to sludge accumulation, and equilibrium metal coprecipitation. This ambient process, to our knowledge previously unknown, agrees with recently reported findings and shows promise for remediation of metals, metalloids, and radionuclides in wastewater, soil, and sediment.

  18. Microbial reduction of [Co(III)-EDTA]⁻ by Bacillus licheniformis SPB-2 strain isolated from a solar salt pan.

    PubMed

    Paraneeiswaran, Arunachalam; Shukla, Sudhir K; Prashanth, K; Rao, T Subba

    2015-01-01

    Naturally stressed habitats are known to be repositories for novel microorganisms with potential bioremediation applications. In this study, we isolated a [Co(III)-EDTA](-) reducing bacterium Bacillus licheniformis SPB-2 from a solar salt pan that is exposed to constant cycles of hydration and desiccation in nature. [Co(III)-EDTA](-) generated during nuclear waste management process is difficult to remove from the waste due to its high stability and solubility. It is reduced form i.e. [Co(II)-EDTA](2-) is less stable though it is toxic. This study showed that B. licheniformis SPB-2 reduced 1mM [Co(III)-EDTA](-) in 14 days when grown in a batch mode. However, subsequent cycles showed an increase in the reduction activity, which was observed up to four cycles. Interestingly, the present study also showed that [Co(III)-EDTA](-) acted as an inducer for B. licheniformis SPB-2 spore germination. Vegetative cells germinated from the spores were found to be involved in [Co(III)-EDTA](-) reduction. More detailed investigations showed that after [Co(III)-EDTA](-) reduction, i.e. [Co(II)-EDTA](2-) complex was removed by B. licheniformis SPB-2 from the bulk liquid by adsorption phenomenon. The bacterium showed a D10 value (radiation dose required to kill 90% cells) of ∼250 Gray (Gy), which signifies the potential use of B. licheniformis SPB-2 for bioremediation of moderately active nuclear waste.

  19. Photodissociation spectroscopy of the Mg{sup +}-acetic acid complex

    SciTech Connect

    Abate, Yohannes; Kleiber, P. D.

    2006-11-14

    We have studied the structure and photodissociation of Mg{sup +}-acetic acid clusters. Ab initio calculations suggest four relatively strongly bound ground state isomers for the [MgC{sub 2}H{sub 4}O{sub 2}]{sup +} complex. These isomers include the cis and trans forms of the Mg{sup +}-acetic acid association complex with Mg{sup +} bonded to the carbonyl O atom of acetic acid, the Mg{sup +}-acetic acid association complex with Mg{sup +} bonded to the hydroxyl O atom of acetic acid, or to a Mg{sup +}-ethenediol association complex. Photodissociation through the Mg{sup +}-based 3p<-3s absorption bands in the near UV leads to direct (nonreactive) and reactive dissociation products: Mg{sup +}, MgOH{sup +}, Mg(H{sub 2}O){sup +}, CH{sub 3}CO{sup +}, and MgCH{sub 3}{sup +}. At low energies the dominant reactive quenching pathway is through dehydration to Mg(H{sub 2}O){sup +}, but additional reaction channels involving C-H and C-C bond activation are also open at higher energies.

  20. Combined efficacy of nisin and pediocin with sodium lactate, citric acid, phytic acid, and potassium sorbate and EDTA in reducing the Listeria monocytogenes population of inoculated fresh-cut produce.

    PubMed

    Bari, M L; Ukuku, D O; Kawasaki, T; Inatsu, Y; Isshiki, K; Kawamoto, S

    2005-07-01

    The inability of chlorine to completely inactivate human bacterial pathogens on whole and fresh-cut produce suggests a need for other antimicrobial washing treatments. Nisin (50 microg/ml) and pediocin (100 AU/ml) individually or in combination with sodium lactate (2%), potassium sorbate (0.02%), phytic acid (0.02%), and citric acid (10 mM) were tested as possible sanitizer treatments for reducing the population of Listeria monocytogenes on cabbage, broccoli, and mung bean sprouts. Cabbage, broccoli, and mung bean sprouts were inoculated with a five-strain cocktail of L. monocytogenes at 4.61, 4.34, and 4.67 log CFU/g, respectively. Inoculated produce was left at room temperature (25 degrees C) for up to 4 h before antimicrobial treatment. Washing treatments were applied to inoculated produce for 1 min, and surviving bacterial populations were determined. When tested alone, all compounds resulted in 2.20- to 4.35-log reductions of L. monocytogenes on mung bean, cabbage, and broccoli, respectively. The combination treatments nisin-phytic acid and nisin-pediocin-phytic acid caused significant (P < 0.05) reductions of L. monocytogenes on cabbage and broccoli but not on mung bean sprouts. Pediocin treatment alone or in combination with any of the organic acid tested was more effective in reducing L. monocytogenes populations than the nisin treatment alone. Although none of the combination treatments completely eliminated the pathogen on the produce, the results suggest that some of the treatments evaluated in this study can be used to improve the microbial safety of fresh-cut cabbage, broccoli, and mung bean sprouts.

  1. EDTA-insoluble, calcium-binding proteoglycan in bovine bone

    NASA Technical Reports Server (NTRS)

    Hashimoto, Y.; Lester, G. E.; Caterson, B.; Yamauchi, M.

    1995-01-01

    A calcium ion precipitable, trypsin-generated proteoglycan fragment has been isolated from the demineralized, EDTA-insoluble matrices of bone. The demineralized matrix was completely digested with trypsin, increasing concentrations of CaCl2 were added to the supernatant, and the resulting precipitates were analyzed. The amount of precipitate gradually increased with higher concentrations of calcium and was reversibly solubilized by EDTA. After molecular sieve and anion exchange chromatography, a proteoglycan-containing peak was obtained. Immunochemical analysis showed that this peak contained chondroitin 4-sulfate and possibly keratan sulfate. Amino acid analysis showed that this proteoglycan contained high amounts of aspartic acid/asparagine (Asx), serine (Ser), glutamic acid/glutamine (Glx), proline (Pro), and glycine (Gly); however, it contained little leucine (Leu) which suggests that it is not a member of the leucine-rich small proteoglycan family. In addition, significant amounts of phosphoserine (P-Ser) and hydroxyproline (Hyp) were identified in hydrolysates of this fraction. A single band (M(r) 59 kDa) was obtained on SDS-PAGE that stained with Stains-all but not with Coomassie Brilliant Blue R-250. If bone powder was trypsinized prior to demineralization, this proteoglycan-containing fraction was not liberated. Collectively, these results indicate that a proteoglycan occurs in the demineralized matrix that is precipitated with CaCl2 and is closely associated with both mineral and collagen matrices. Such a molecule might facilitate the structural network for the induction of mineralization in bone.

  2. Extractability of zinc, cadmium, and nickel in soils amended with EDTA

    SciTech Connect

    Li, Zhenbin; Shuman, L.M.

    1996-04-01

    Synthetic chelating agents are produced in large quantities for use in many industrial applications. Certain chelates, such as ethylenediaminetetraacetic acid (EDTA), are persistent in the environment. The presence of EDTA in soil may alter the mobility and transport of Zn, Cd, and Ni in soils because of the formation of water soluble chelates, thus increasing the potential for metal pollution of natural waters. Mobility of metals is related to their extractability. To investigate metal extractability affected by EDTA, Zn, Cd, and Ni were added to a portion of eight Georgia topsoil samples at rates of 75.9, 1.62, and 4.30 mg kg{sup -1}, respectively. Both natural and metal-amended soils were treated with Na{sub 2-}EDTA at rates of 0, 1.0, and 2.0 g kg{sup -1}. After 5 months of incubation, soil samples were extracted with Mehlich-1, DTPA (diethylenetriamine-pentaacetic acid) and 1 M Mg(NO{sub 3}){sub 2}, the latter of which extracts the exchangeable form of metals. Results showed that Zn and Ni in Mehlich-1 and DTPA extractions increased with increasing rates of EDTA. The increase for Cd was not as great as for Zn or Ni. Similar changes were found for the Mg(NO{sub 3}){sub 2} extraction. As a percentage of total metal concentration, the Mehlich-1 and DTPA extractable Zn was greater than Ni in the natural soils, and the order for the metal-amended soils was Cd > Zn > Ni. The results also suggested that EDTA significantly elevated the extractability of Zn and Ni in both natural and metal-amended soils. The order of mobility based on extractability was: Cd > Zn > Ni for metals added to soils, but when EDTA was present, added Ni was more extractable than Zn or Cd. 36 refs., 5 tabs.

  3. Enhanced biological phosphorus removal employing EDTA disodium

    SciTech Connect

    Bojinova, D.; Velkova, R.

    1996-12-31

    The biological phosphorus removal is a promising alternative to the conventional chemical technologies for processing of phosphate raw materials. The object of this study was the effect of EDTA disodium on the biotreatment of tunisian phosphorite with the strain of Aspergillus niger. The incubation was carried out in two nutritive mediums, with different phosphate content. The experimental results showed that the additives of EDTA disodium in the nutritive medium increased the rate of extraction of P{sub 2}O{sub 5} and shortened significantly the time for biological leaching. 5 refs., 3 figs., 2 tabs.

  4. Reduction of mercury from mackerel fillet using combined solution of cysteine, EDTA, and sodium chloride.

    PubMed

    Hajeb, P; Jinap, S

    2012-06-13

    An acidic solution containing mercury chelating agents to eliminate mercury in raw fish (mackerel) fillet was developed. The solution contained hydrochloric acid, sodium hydroxide, cysteine, EDTA, and NaCl. The optimum conditions for mercury reduction were achieved using response surface methodology (RSM) at cysteine concentration of 1.25%, EDTA of 275 mg/L, NaCl of 0.5%, pH of 3.75, and exposure time of 18 min. The optimized conditions produced a solution which can remove up to 91% mercury from raw fish fillet. Cysteine and EDTA were identified as potential chelating agents with the greatest potential for use. The solution can be employed in fish industries to reduce mercury in highly contaminated fish.

  5. Photolysis of copper(II)-amino acid complexes in water

    SciTech Connect

    Hayase, K.; Zepp, R.G. )

    1991-07-01

    Kinetics of the photolysis of Cu{sup 2+}-amino acid complexes were investigated under sunlight or monochromatic radiation. Under sunlight (latitude 40{degree}N) in the absence of dioxygen, the mean half-lives estimated for the photoreduction of the bis-Cu{sup 2+} complexes (CuL{sub 2}) at pH 8.0 and 25C were 0.55, 1.6, 8.6, 8.8, 45. and 71 days for L = tris(hydroxymethyl)aminomethane (Tris), {beta}-alanine, L-aspartic acid, L-glutamic acid, glycine, and histidine, respectively. Under monochromatic UV irradiation (310 nm) with dioxygen absent, quantum yields for the photoproduction of Cu(I) from CuL{sub 2} were found to be 0.071, 0.098, 0.063, 0.066, 0.025, and 0.0011 for L = Tris, {beta}-alanine, L-aspartic acid, L-glutamic acid, glycine, and L-histidine, respectively. The effects of pH on the quantum yields were determined for Cu{sup 2+}-{beta}-alanine and Cu{sup 2+}-Tris complexes. Decreases in quantum yields observed with increasing acidity were attributed to changes in speciation from predominantly CuL{sub 2} to less photoreactive complexes, mainly CuL and Cu{sup 2+}. In air-saturated solutions, rates and quantum yields for Cu(I) formation were sharply reduced and hydrogen peroxide was formed. Results of the study suggest that photoreactions of Cu{sup 2+} coordination complexes may contribute to its toxicity to aquatic biota.

  6. Oxidation of Fe(II)-EDTA by nitrite and by two nitrate-reducing Fe(II)-oxidizing Acidovorax strains.

    PubMed

    Klueglein, N; Picardal, F; Zedda, M; Zwiener, C; Kappler, A

    2015-03-01

    The enzymatic oxidation of Fe(II) by nitrate-reducing bacteria was first suggested about two decades ago. It has since been found that most strains are mixotrophic and need an additional organic co-substrate for complete and prolonged Fe(II) oxidation. Research during the last few years has tried to determine to what extent the observed Fe(II) oxidation is driven enzymatically, or abiotically by nitrite produced during heterotrophic denitrification. A recent study reported that nitrite was not able to oxidize Fe(II)-EDTA abiotically, but the addition of the mixotrophic nitrate-reducing Fe(II)-oxidizer, Acidovorax sp. strain 2AN, led to Fe(II) oxidation (Chakraborty & Picardal, 2013). This, along with other results of that study, was used to argue that Fe(II) oxidation in strain 2AN was enzymatically catalyzed. However, the absence of abiotic Fe(II)-EDTA oxidation by nitrite reported in that study contrasts with previously published data. We have repeated the abiotic and biotic experiments and observed rapid abiotic oxidation of Fe(II)-EDTA by nitrite, resulting in the formation of Fe(III)-EDTA and the green Fe(II)-EDTA-NO complex. Additionally, we found that cultivating the Acidovorax strains BoFeN1 and 2AN with 10 mM nitrate, 5 mm acetate, and approximately 10 mM Fe(II)-EDTA resulted only in incomplete Fe(II)-EDTA oxidation of 47-71%. Cultures of strain BoFeN1 turned green (due to the presence of Fe(II)-EDTA-NO) and the green color persisted over the course of the experiments, whereas strain 2AN was able to further oxidize the Fe(II)-EDTA-NO complex. Our work shows that the two used Acidovorax strains behave very differently in their ability to deal with toxic effects of Fe-EDTA species and the further reduction of the Fe(II)-EDTA-NO nitrosyl complex. Although the enzymatic oxidation of Fe(II) cannot be ruled out, this study underlines the importance of nitrite in nitrate-reducing Fe(II)- and Fe(II)-EDTA-oxidizing cultures and demonstrates that Fe(II)-EDTA cannot

  7. [Effects of EDTA on the Reductive Dechlorination of 2,4-D by Pd/Fe].

    PubMed

    Zhou, Hong-yi; Nie, Ya-zhong; Chen, Yong; Lei, Shuang-jian

    2016-02-15

    In Pd/Fe system, zero-valent iron (ZVI) passivation layer is easily formed on the particle surface during the catalytic reductive dechlorination of chlorinated organics, hindering further dechlorination of target contaminants. In this paper, the passivation layer on the Pd/Fe particle surfaces could be eliminated by the chelation of disodium edetate (EDTA) with Fe2+, Fe3+, making the reductive dechlorination continue. The experiment investigated the effects of EDTA addition manner and dosage, pH, Pd loading and temperature on dechlorination of 2,4-dichlorophenoxyacetic acid (2,4-D) by Pd/Fe. The conclusions can be summarized as follows: (1) Phenoxyacetic acid (PA) generation ratio reached 90. 7% within 20 min with EDTA concentration of 25.0 mmol x L(-1) and flow rate of 20 mL x h(-1), while it was only 74.5% after 210 min in the system without EDTA. (2) The EDTA could chelate the Fe2+ and Fe3+ generated from the process of 2,4-D dechlorination by Pd/Fe, preventing or slowing down the formation of passivation layer, and accelerating the reduction efficiency. (3) The appropriate experimental parameters for 2,4-D removal were as follows: EDTA flow rate of 20 mL x h(-1), CEDTA of 25.0 mmol x L(-1), Pd loading of 0.050%, 200 r x min(-1), pH 4.2 and 30.0 degrees C. The removal percentage of 20.0 mg x L(-1) 2,4-D reached nearly up to 100% within 210 min under these conditions. (4) The intermediates of 2, 4-D catalytic dechlorination included 2-chlorophenoxvacetic acid (2-CPA) and trace 4-chloronhenoxyacetic acid (4-CPA), and the end product was PA.

  8. [Effects of EDTA on the Reductive Dechlorination of 2,4-D by Pd/Fe].

    PubMed

    Zhou, Hong-yi; Nie, Ya-zhong; Chen, Yong; Lei, Shuang-jian

    2016-02-15

    In Pd/Fe system, zero-valent iron (ZVI) passivation layer is easily formed on the particle surface during the catalytic reductive dechlorination of chlorinated organics, hindering further dechlorination of target contaminants. In this paper, the passivation layer on the Pd/Fe particle surfaces could be eliminated by the chelation of disodium edetate (EDTA) with Fe2+, Fe3+, making the reductive dechlorination continue. The experiment investigated the effects of EDTA addition manner and dosage, pH, Pd loading and temperature on dechlorination of 2,4-dichlorophenoxyacetic acid (2,4-D) by Pd/Fe. The conclusions can be summarized as follows: (1) Phenoxyacetic acid (PA) generation ratio reached 90. 7% within 20 min with EDTA concentration of 25.0 mmol x L(-1) and flow rate of 20 mL x h(-1), while it was only 74.5% after 210 min in the system without EDTA. (2) The EDTA could chelate the Fe2+ and Fe3+ generated from the process of 2,4-D dechlorination by Pd/Fe, preventing or slowing down the formation of passivation layer, and accelerating the reduction efficiency. (3) The appropriate experimental parameters for 2,4-D removal were as follows: EDTA flow rate of 20 mL x h(-1), CEDTA of 25.0 mmol x L(-1), Pd loading of 0.050%, 200 r x min(-1), pH 4.2 and 30.0 degrees C. The removal percentage of 20.0 mg x L(-1) 2,4-D reached nearly up to 100% within 210 min under these conditions. (4) The intermediates of 2, 4-D catalytic dechlorination included 2-chlorophenoxvacetic acid (2-CPA) and trace 4-chloronhenoxyacetic acid (4-CPA), and the end product was PA. PMID:27363149

  9. Electrospun polymer nanofibers reinforced by tannic acid/Fe+++ complexes

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Nanofibers and fibrous mats of polyvinyl alcohol (PVA) loaded with tannic acid (TA) and ferric ion (Fe+++) complexes (TA-Fe+++) were synthesized by the electrospinning technique. The spinning solutions were characterized for surface tension, electrical conductivity, and viscosity. It was found that ...

  10. Anaerobic Biotransformation and Mobility of Pu and PuEDTA

    SciTech Connect

    Xun, Luying

    2005-06-01

    The objective of this report is to isolate anaerobic EDTA-degrading bacteria. Although our goal is to isolate anaerobic EDTA degraders, we initiated the experiments to include nitrilotriacetate (NTA), which is a structure homologue of EDTA. All the aerobic EDTA degraders can degrade NTA, but the isolated NTA degraders cannot degrade EDTA. Since NTA is a simpler structure homologue, it is likely that EDTA-degrading ability is evolved from NTA degradation. This hypothesis is further supported from our characterization of EDTA and NTA-degrading enzymes and genes (J. Bact. 179:1112-1116; and Appl. Environ. Microbiol. 67:688-695). The EDTA monooxygenase and NTA monooxygenase are highly homologous. EDTA monooxygenase can use both EDTA and NTA as substrates, but NTA monooxygenase can only use NTA as a substrate. Thus, we put our effort to isolate both NTA and EDTA degraders. In case, an anaerobic EDTA degrader is not immediately enriched, we will try to evolve the NTA degraders to use EDTA. Both aerobic and anaerobic enrichment cultures were set.

  11. Biodegradation of PuEDTA and Impacts on Pu Mobility

    SciTech Connect

    Xun, Luying; Bolton, Harvey, Jr.

    2003-06-01

    This project is part of a major project (PI, Dr. Harvey Bolton, Jr. at PNNL) regarding plutonium mobility in the subsurface. Ethylenediaminetetraacetate (EDTA) is a common chelating agent that can increase the mobility of radionuclides and heavy metals in groundwater. Biodegradation of EDTA decreases the enhanced mobility. The overall objective is to understand how microbial degradation affects Plutonium-EDTA transport in the environment, and the specific objective of this component is to understand how microorganisms degrade EDTA. Over the past two years, significant progress has been made to the understanding on how EDTA is degraded by an EDTA-degrading bacterium BNC1. The characterization of EDTA and nitrilotriacetate (NTA) transport into BNC1 cells is summarized here. The uptake is the limiting step in EDTA and NTA degradation. The objectives of near-term research are described. We are making progress as projected in the proposal.

  12. Ru(EDTA) mediated partial reduction of O2 by H2S.

    PubMed

    Chatterjee, Debabrata; Jaiswal, Namita; Sarkar, Papiya

    2015-04-28

    An effective procedure for selective reduction of O2 to H2O2 exploring the use of hydrogen sulfide, an obnoxious industrial pollutant as reductant is reported herein. The reduction of [Ru(III)(EDTA)pz](-) (EDTA(4-) = ethylenediaminetetraacetate; pz = pyrazine) by hydrogen sulfide resulting in the formation of a red [Ru(II)(EDTA)pz](2-) complex (λmax = 462 nm) has been studied spectrophotometrically and kinetically using both rapid scan and stopped-flow techniques. The time course of the reaction was followed as a function of [HS(-)]i, pH (5.5-8.5), and temperature. Alkali metal ions were found to have a positive influence (K(+) > Na(+) > Li(+)) on the reaction rate. Kinetic data and activation parameters are interpreted in terms of a mechanism (admittedly speculative) involving outer-sphere electron transfer between the reaction partners. Reaction of the red [Ru(II)(EDTA)pz](2-) complex with molecular oxygen regenerates the [Ru(III)(EDTA)pz](-) species in the reacting system along with the formation of H2O2, a partially reduced product of dioxygen (O2) reduction. A detailed reaction mechanism in agreement with the spectral and kinetic data is presented.

  13. Photocatalytic removal of selenite and selenate species: effect of EDTA and other process variables.

    PubMed

    Labaran, B A; Vohra, M S

    2014-01-01

    TiO2-assisted photocatalysis was employed for the removal of aqueous phase selenite and selenate species in conjunction with EDTA as a hole (h+) scavenger. Findings from the binary selenite/EDTA and selenate/EDTA systems showed high selenite and selenate removal at pH 4 and pH 6, with faster removal kinetics noted for the selenite species compared with the selenate species that showed a gradual change over the reaction course. The noted removal of selenite and selenate was attributed to their reduction by the conduction band electrons (e-). The effect of pH studies indicated high selenite, selenate, and EDTA removal in the acidic pH range, with the following specific trend: pH 4 > pH 6 > pH 12. Different from the EDTA studies, the use of thiocyanate alone did not initiate reduction of selenium oxyanions, and hence, its role as a hole scavenger in the present systems was not evident. However, the addition of EDTA to respective selenite/selenate/thiocyanate system at pH 4 did yield near complete removal of selenite and selenate species. The marginal role of thiocyanate as a hole scavenger was attributed to its negligible adsorption onto TiO2 surface. Furthermore, at pH 4 and within 3 h reaction time, enhanced selenate removal was noted with an increase in its initial concentration from 20 to 100 ppm, with near complete selenate removal noted for both cases. In general, findings from the present work indicate that both selenite and selenate can be successfully removed from the aqueous phase employing the TiO2-mediated photocatalysis and h(+)-scavenging agent EDTA.

  14. EDTA redistribution of lead and cadmium into the soft tissues in a human with a high lead burden - should DMSA always be used to follow EDTA in such cases?

    PubMed

    Crinnion, Walter J

    2011-06-01

    Intravenous sodium calcium ethylene diamine tetra acetic acid (EDTA) and oral 2,3-dimercaptosuccinic acid (DMSA) have both been used to reduce the burden of lead in humans. Each of these agents enhances the mobilization of lead from different areas of the body - EDTA from the trabecular bone and DMSA from the soft tissue. A study of Korean battery workers revealed that EDTA appeared to increase the soft tissue burden of lead, resulting in increased levels of aminolevulinic acid and greater subsequent lead mobilization with DMSA. This case report discusses a patient with a higher-than-normal lead burden who exhibited increased tissue lead burden after intravenous EDTA. The elevated tissue burden of lead was still present, albeit lower, after five consecutive days of oral DMSA therapy. If this single case is representative of a typical human response to the use of intravenous (IV) EDTA for lead, then it suggests that all persons undergoing such treatment should be administered oral DMSA for a minimum of one week after EDTA treatment.

  15. 21 CFR 73.2120 - Disodium EDTA-copper.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 1 2012-04-01 2012-04-01 false Disodium EDTA-copper. 73.2120 Section 73.2120 Food... COLOR ADDITIVES EXEMPT FROM CERTIFICATION Cosmetics § 73.2120 Disodium EDTA-copper. (a) Identity. The color additive disodium EDTA-copper is disodium ] (4-)-N,N′,O,O′,O N,O N′] cuprate (2-)....

  16. 21 CFR 73.2120 - Disodium EDTA-copper.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 1 2014-04-01 2014-04-01 false Disodium EDTA-copper. 73.2120 Section 73.2120 Food... COLOR ADDITIVES EXEMPT FROM CERTIFICATION Cosmetics § 73.2120 Disodium EDTA-copper. (a) Identity. The color additive disodium EDTA-copper is disodium ] (4-)-N,N′,O,O′,O N,O N′] cuprate (2-)....

  17. 21 CFR 73.2120 - Disodium EDTA-copper.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 1 2010-04-01 2010-04-01 false Disodium EDTA-copper. 73.2120 Section 73.2120 Food... COLOR ADDITIVES EXEMPT FROM CERTIFICATION Cosmetics § 73.2120 Disodium EDTA-copper. (a) Identity. The color additive disodium EDTA-copper is disodium ] (4-)-N,N′,O,O′,O N,O N′] cuprate (2-)....

  18. 21 CFR 73.2120 - Disodium EDTA-copper.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 1 2013-04-01 2013-04-01 false Disodium EDTA-copper. 73.2120 Section 73.2120 Food... COLOR ADDITIVES EXEMPT FROM CERTIFICATION Cosmetics § 73.2120 Disodium EDTA-copper. (a) Identity. The color additive disodium EDTA-copper is disodium ] (4-)-N,N′,O,O′,O N,O N′] cuprate (2-)....

  19. 21 CFR 73.2120 - Disodium EDTA-copper.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 1 2011-04-01 2011-04-01 false Disodium EDTA-copper. 73.2120 Section 73.2120 Food... COLOR ADDITIVES EXEMPT FROM CERTIFICATION Cosmetics § 73.2120 Disodium EDTA-copper. (a) Identity. The color additive disodium EDTA-copper is disodium ] (4-)-N,N′,O,O′,O N,O N′] cuprate (2-)....

  20. Denaturation of metalloproteins with EDTA to facilitate enzymatic digestion and mass fingerprinting.

    PubMed

    Janecki, Dariusz J; Reilly, James P

    2005-01-01

    Metal ions bound to a protein often stabilize tertiary and/or quaternary structure. Consequently, the digestion of metalloproteins that precedes analysis by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry is frequently incomplete. It is demonstrated that ethylenediaminetetraacetic acid (EDTA) successfully destabilizes metalloprotein structure and thereby facilitates tryptic digestion and protein identification.

  1. Denaturation of metalloproteins with EDTA to facilitate enzymatic digestion and mass fingerprinting.

    PubMed

    Janecki, Dariusz J; Reilly, James P

    2005-01-01

    Metal ions bound to a protein often stabilize tertiary and/or quaternary structure. Consequently, the digestion of metalloproteins that precedes analysis by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry is frequently incomplete. It is demonstrated that ethylenediaminetetraacetic acid (EDTA) successfully destabilizes metalloprotein structure and thereby facilitates tryptic digestion and protein identification. PMID:15834845

  2. The improved phytoextraction of lead (Pb) and the growth of maize (Zeamays L.): the role of plant growth regulators (GA3 and IAA) and EDTA alone and in combinations.

    PubMed

    Hadi, Fazal; Bano, Asghari; Fuller, Michael P

    2010-06-01

    This investigation was made to examine the role of gibberellic acid (GA(3)), indole-3-acetic acid (IAA) and EDTA in improving phytoextraction of the Pb and plant growth on Pb added soil. GA(3), IAA and EDTA were applied separately and in combinations. GA(3) and IAA were applied as foliar spray and seed soaking. EDTA was applied in single and split doses. Analysis of the Pb in different parts of plant was carried out using atomic absorption/flame spectrophotometer. EDTA significantly reduced the plant growth and dry biomass, whereas GA(3) and IAA foliar spray increased it significantly when compared with control (only Pb added soil). In combined treatments of EDTA+GA(3) and EDTA+IAA, the growth and biomass was restored, which shows that GA(3) and IAA did compensate the negative effect of EDTA on plant growth. The separate treatments of EDTA, GA(3) and IAA increased the Pb uptake and translocation significantly moreover in combine treatments, synergistic effect was found and remarkable increase in Pb uptake and translocation into shoot was observed. EDTA increased the Pb uptake but declined the biomass; subsequently the total Pb accumulation was decreased in plant. The maximum total Pb was found in combined treatment of EDTA+GA(3). These findings suggest more investigation to find a combination of GA(3) with a very low concentration of EDTA, as in high concentration it causes soil and ground water pollution.

  3. Total Degradation of EDTA by Mixed Cultures and a Bacterial Isolate

    PubMed Central

    Nörtemann, Bernd

    1992-01-01

    A bacterial mixed culture, which was obtained from sewage by a special enrichment procedure, utilized EDTA as the sole source of carbon and nitrogen for growth. High concentrations of mineral salts, particularly CaCl2, or the use of a mineral base without nitrogen protected the cells from inactivation after transfer into fresh medium containing 200-mg/liter (0.67 mM) EDTA. The chemical speciation did not influence the biodegradability of EDTA. However, when resting cells of the mixed culture were incubated with EDTA in the presence of an equivalent molar amount of FeCl3, the reaction came to a halt before the complete consumption of the substrate. A gram-negative isolate from the mixed population, BNC1, also metabolized EDTA in monoculture. Growth of the pure culture was promoted by biotin or folic acid but was always accompanied by the accumulation of unidentified metabolites and was slow (μmax, 0.024 h-1) compared with that of the original community (μmax, 0.036 h-1). Images PMID:16348653

  4. The EDTA Amendment in Phytoextraction of (134)Cs From Soil by Indian Mustard (Brassica juncea).

    PubMed

    Tjahaja, Poppy Intan; Sukmabuana, Putu; Roosmini, Dwina

    2015-01-01

    Soil contamination with radiocaesium is a significant problem at any countries when a nuclear accident occurred. Recently, phytoextraction technique is developed to remediate the contaminated environment. However, the application is limited by the availability of the contaminant for root uptake. Therefore, a green house trial experiment of soil amendment with ethylene diamine tetraacetic acid (EDTA) has been conducted to examine (134)Cs availability for root uptake. Two groups of Indian mustard (Brassica juncea) were cultivated in (134)Cs contaminated soil. The soil in the first group was treated with EDTA amendment, while the other was not. Plant growth was observed gravimetrically and the (134)Cs concentration in soil as well as plants were determined using gamma spectrometry. The plant uptake capacity was determined as transfer factor (Fv), and the Fv values of 0.22 ± 0.0786 and 0.12 ± 0.039 were obtained for the soil treated with and without EDTA amendment, respectively. The phytoextraction efficiency of the plant cultivated in (134)Cs contaminated soil both with and without EDTA amendment was low. The EDTA amendment to the soil seems to enhance the (134)Cs availability for root uptake of Indian mustard and can still be considered to assist the field phytoremediation of contaminated soil.

  5. The EDTA Amendment in Phytoextraction of (134)Cs From Soil by Indian Mustard (Brassica juncea).

    PubMed

    Tjahaja, Poppy Intan; Sukmabuana, Putu; Roosmini, Dwina

    2015-01-01

    Soil contamination with radiocaesium is a significant problem at any countries when a nuclear accident occurred. Recently, phytoextraction technique is developed to remediate the contaminated environment. However, the application is limited by the availability of the contaminant for root uptake. Therefore, a green house trial experiment of soil amendment with ethylene diamine tetraacetic acid (EDTA) has been conducted to examine (134)Cs availability for root uptake. Two groups of Indian mustard (Brassica juncea) were cultivated in (134)Cs contaminated soil. The soil in the first group was treated with EDTA amendment, while the other was not. Plant growth was observed gravimetrically and the (134)Cs concentration in soil as well as plants were determined using gamma spectrometry. The plant uptake capacity was determined as transfer factor (Fv), and the Fv values of 0.22 ± 0.0786 and 0.12 ± 0.039 were obtained for the soil treated with and without EDTA amendment, respectively. The phytoextraction efficiency of the plant cultivated in (134)Cs contaminated soil both with and without EDTA amendment was low. The EDTA amendment to the soil seems to enhance the (134)Cs availability for root uptake of Indian mustard and can still be considered to assist the field phytoremediation of contaminated soil. PMID:26208541

  6. Nucleic Acid-Peptide Complex Phase Controlled by DNA Hybridization

    NASA Astrophysics Data System (ADS)

    Vieregg, Jeffrey; Lueckheide, Michael; Leon, Lorraine; Marciel, Amanda; Tirrell, Matthew

    When polyanions and polycations are mixed, counterion release drives formation of polymer-rich complexes that can either be solid (precipitates) or liquid (coacervates) depending on the properties of the polyelectrolytes. These complexes are important in many fields, from encapsulation of industrial polymers to membrane-free segregation of biomolecules such as nucleic acids and proteins. Condensation of long double-stranded DNA has been studied for several decades, but comparatively little attention has been paid to the polyelectrolyte behavior of oligonucleotides. We report here studies of DNA oligonucleotides (10 - 88 nt) complexed with polylysine (10 - 100 aa). Unexpectedly, we find that the phase of the resulting complexes is controlled by the hybridization state of the nucleic acid, with double-stranded DNA forming precipitates and single-stranded DNA forming coacervates. Stability increases with polyelectrolyte length and decreases with solution salt concentration, with complexes of the longer double-stranded polymers undergoing precipitate/coacervate/soluble transitions as ionic strength is increased. Mixing coacervates formed by complementary single-stranded oligonucleotides results in precipitate formation, raising the possibility of stimulus-responsive material design.

  7. EDTA Chelation Therapy to Reduce Cardiovascular Events in Persons with Diabetes.

    PubMed

    Ouyang, Pamela; Gottlieb, Sheldon H; Culotta, Valerie L; Navas-Acien, Ana

    2015-11-01

    The Trial to Assess Chelation Therapy (TACT) was a randomized double-blind placebo-controlled trial enrolling patients age ≥50 years with prior myocardial infarction. TACT used a 2 × 2 factorial design to study ethylene diamine tetraacetic acid (EDTA) chelation and high-dose vitamin supplementation. Chelation provided a modest but significant reduction in cardiovascular endpoints. The benefit was stronger and significant among participants with diabetes but absent in those without diabetes. Mechanisms by which chelation might reduce cardiovascular risk in persons with diabetes include the effects of EDTA chelation on transition and toxic metals. Transition metals, particularly copper and iron, play important roles in oxidative stress pathways. Toxic metals, in particular cadmium and lead, are toxic for the cardiovascular system. This review discusses the epidemiologic evidence and animal and human studies supporting the role of these metals in the development of diabetes and ischemic heart disease and potential ways by which EDTA chelation could confer cardiovascular benefit.

  8. Pharmacology of bile acid receptors: Evolution of bile acids from simple detergents to complex signaling molecules.

    PubMed

    Copple, Bryan L; Li, Tiangang

    2016-02-01

    For many years, bile acids were thought to only function as detergents which solubilize fats and facilitate the uptake of fat-soluble vitamins in the intestine. Many early observations; however, demonstrated that bile acids regulate more complex processes, such as bile acids synthesis and immune cell function through activation of signal transduction pathways. These studies were the first to suggest that receptors may exist for bile acids. Ultimately, seminal studies by many investigators led to the discovery of several bile acid-activated receptors including the farnesoid X receptor, the vitamin D receptor, the pregnane X receptor, TGR5, α5 β1 integrin, and sphingosine-1-phosphate receptor 2. Several of these receptors are expressed outside of the gastrointestinal system, indicating that bile acids may have diverse functions throughout the body. Characterization of the functions of these receptors over the last two decades has identified many important roles for these receptors in regulation of bile acid synthesis, transport, and detoxification; regulation of glucose utilization; regulation of fatty acid synthesis and oxidation; regulation of immune cell function; regulation of energy expenditure; and regulation of neural processes such as gastric motility. Through these many functions, bile acids regulate many aspects of digestion ranging from uptake of essential vitamins to proper utilization of nutrients. Accordingly, within a short time period, bile acids moved beyond simple detergents and into the realm of complex signaling molecules. Because of the important processes that bile acids regulate through activation of receptors, drugs that target these receptors are under development for the treatment of several diseases, including cholestatic liver disease and metabolic syndrome. In this review, we will describe the various bile acid receptors, the signal transduction pathways activated by these receptors, and briefly discuss the physiological processes that

  9. The influence of EDTA application on the interactions of cadmium, zinc, and lead and their uptake of rainbow pink (Dianthus chinensis).

    PubMed

    Lai, Hung-Yu; Chen, Zueng-Sang

    2006-10-11

    Soil used in this study was artificially contaminated with Cd, Zn, Pb, or applied in combinations (Cd-Zn, Cd-Pb, Zn-Pb, or Cd-Zn-Pb) to study the interactions of metals in soil contaminated with multiple metals. After planting rainbow pink (Dianthus chinensis) in these soils for 21 days, three different concentrations of ethylenedinitrilotetraacetic acid (EDTA) solutions were added to study the effect of applying EDTA on the interactions among these metals. The concentrations of Cd, Zn, and Pb in the soil solutions of different metals-treated soils increased significantly after applying 5 mmol EDTA kg(-1) soil (p<0.05). The potential of groundwater contamination will increase after applying EDTA and it is not recommended to be in situ used or have to use very carefully. The existence of Pb in the Cd-contaminated soil enhanced the uptake of Cd in rainbow pink in the treatments of control and 2 mmol EDTA kg(-1) soil. Cadmium inhibited the concentration of Zn without applying EDTA. However, whether the application of EDTA or not and the applied EDTA concentration had the greatest effect on the uptake of Pb when compared to Cd and Zn. After applying 5 mmol EDTA kg(-1) soil, Cd or Zn in the Pb-contaminated soil inhibited the uptake of Pb in rainbow pink, but there were no effect in other treatments.

  10. 1064-nm Nd:YAG and 980-nm Diode Laser EDTA Agitation on the Retention of an Epoxy-Based Sealer to Root Dentin.

    PubMed

    Macedo, Helena Suleiman de; Messias, Danielle Cristine Furtado; Rached-Júnior, Fuad Jacob; Oliveira, Ligia Teixeira de; Silva-Sousa, Yara Teresinha Correa; Raucci-Neto, Walter

    2016-01-01

    Root canal irrigants are used to minimize the negative effects of smear layer on endodontic sealer retention. The aim of this study was to evaluate the efficacy of agitation of 17% ethylenediaminetetraacetic acid (EDTA) with ultrasonic, 1064-nm Nd:YAG and 980-nm diode laser on the retention of an epoxy-based sealer to the root canal walls. Forty single-rooted bovine teeth were instrumented with ProTaper rotary system and divided into four groups according to the final irrigation protocol (n = 10): (1) 17% EDTA (control); (2) 17% EDTA with 50-s ultrasonic agitation; (3) 17% EDTA with 50-s diode laser (2-W) agitation; and (4) 17% EDTA with 50-s Nd:YAG (1.5-W) laser agitation. After endodontic filling with gutta-percha F5 master cone and Sealer 26, the roots were sectioned at the cervical, middle, and apical root thirds to obtain 1.5-mm slices. Push-out tests were performed using a universal testing machine at a 1 mm/min crosshead speed. Data were analyzed using two-way ANOVA and Tukey's tests (α=0.05). Apical root thirds had significant higher retention values than cervical and middle thirds (p < 0.05). EDTA with 1064-nm Nd:YAG or 980-nm diode laser presented the highest retention values and was significantly different from EDTA with ultrasonic agitation and EDTA only (p < 0.05). Adhesive failures were predominant to EDTA only group. Mixed failures were predominant to all agitation groups. 1064-nm Nd:YAG and 980-nm diode laser EDTA agitation enhanced the retention of the epoxy-based sealer to the root canal walls compared with that due to EDTA only or EDTA with ultrasonic agitation. PMID:27652705

  11. 1064-nm Nd:YAG and 980-nm Diode Laser EDTA Agitation on the Retention of an Epoxy-Based Sealer to Root Dentin.

    PubMed

    Macedo, Helena Suleiman de; Messias, Danielle Cristine Furtado; Rached-Júnior, Fuad Jacob; Oliveira, Ligia Teixeira de; Silva-Sousa, Yara Teresinha Correa; Raucci-Neto, Walter

    2016-01-01

    Root canal irrigants are used to minimize the negative effects of smear layer on endodontic sealer retention. The aim of this study was to evaluate the efficacy of agitation of 17% ethylenediaminetetraacetic acid (EDTA) with ultrasonic, 1064-nm Nd:YAG and 980-nm diode laser on the retention of an epoxy-based sealer to the root canal walls. Forty single-rooted bovine teeth were instrumented with ProTaper rotary system and divided into four groups according to the final irrigation protocol (n = 10): (1) 17% EDTA (control); (2) 17% EDTA with 50-s ultrasonic agitation; (3) 17% EDTA with 50-s diode laser (2-W) agitation; and (4) 17% EDTA with 50-s Nd:YAG (1.5-W) laser agitation. After endodontic filling with gutta-percha F5 master cone and Sealer 26, the roots were sectioned at the cervical, middle, and apical root thirds to obtain 1.5-mm slices. Push-out tests were performed using a universal testing machine at a 1 mm/min crosshead speed. Data were analyzed using two-way ANOVA and Tukey's tests (α=0.05). Apical root thirds had significant higher retention values than cervical and middle thirds (p < 0.05). EDTA with 1064-nm Nd:YAG or 980-nm diode laser presented the highest retention values and was significantly different from EDTA with ultrasonic agitation and EDTA only (p < 0.05). Adhesive failures were predominant to EDTA only group. Mixed failures were predominant to all agitation groups. 1064-nm Nd:YAG and 980-nm diode laser EDTA agitation enhanced the retention of the epoxy-based sealer to the root canal walls compared with that due to EDTA only or EDTA with ultrasonic agitation.

  12. Anodic oxidation of ethylenediaminetetraacetic acid on platinum electrode in alkaline medium

    SciTech Connect

    Pakalapati, S.N.R.; Popov, B.N.; White, R.E.

    1996-05-01

    Ethylenediaminetetraacetic acid (EDTA) forms strong metal complexes and is often used to remove scale from heat-transfer equipment and to decontaminate equipment exposed to radioactive material. However, the resultant waste in the form of EDTA-metal complex is hard to treat due to the high stability of such complexes. The anodic oxidation of ethylenediaminetetraacetic acid (EDTA) was studied in alkaline medium on a smooth platinum electrode. Bulk electrolysis indicated that stable organic intermediates (formaldehyde and glyoxal) are formed during the oxidation of EDTA and that complete oxidation to CO{sub 2} can be achieved. The proposed pathway suggests that the acetate groups in EDTA are initially oxidized, generating formaldehyde and ethylenediamine. The rest potential of EDTA (0.066 to 0.164 V vs. Hg/HgO) was observed to be higher than for other organic species. In alkaline medium, very little EDTA oxidation was found to occur on bare platinum. Limiting-current behavior due to PtO formation was observed immediately positive of the rest potential. Tafel behavior (Tafel slope 120 mV/dec) was observed in the potential region positive of the cessation of the bulk of oxide film formation and negative of the onset of O{sub 2} evolution. The reaction order of EDTA was determined to be {approximately}0.5, and that of OH{sup {minus}} was close to zero. The reaction mechanism consistent with the experimental data involves Temkin-type adsorption and a first-electron-transfer rate-determining step.

  13. Purification and characterization of a lyase from the EDTA-degrading bacterial strain DSM 9103 that catalyzes the splitting of [S,S]-ethylenediaminedisuccinate, a structural isomer of EDTA.

    PubMed

    Witschel, M; Egli, T

    The bacterial strain DSM 9103, able to utilize EDTA as a sole source of carbon, nitrogen, and energy, is also capable to grow with [S,S]-ethylenediaminedisuccinate ([S,S]-EDDS), a structural isomer of EDTA. In cell-free extracts of [S,S]-EDDS-grown bacteria, [S,S]-EDDS degradation was observed in the absence of any cofactors. An enzyme was purified 41-fold that catalyzed the non-hydrolytic splitting of [S,S]-EDDS leading to the formation of fumarate and N-(2-aminoethyl) aspartic acid. These data strongly suggest that the enzyme belongs to the group of carbon-nitrogen lyases. The splitting reaction was reversible, and an equilibrium constant of approximately 43.0 10(-1) M was determined. Out of the three stereo-isomers of EDDS, [S,S]- and [R,S]-EDDS were accepted as substrates by the lyase, whereas [R,R]-EDDS remained unchanged in assays with both cell-free extracts and pure enzyme. The enzyme catalyzed the transformation of free [S,S]-EDDS and of [S,S]-EDDS-metal complexes with stability constant lower than 10, namely of MgEDDS, CaEDDS, BaEDDS and to a small extent also of MnEDDS; FeIIIEDDS, NiEDDS, CuEDDS, CoEDDS and ZnEDDS were not transformed.

  14. Biotransformation of PuEDTA: Implications to Pu Immobilization

    SciTech Connect

    Bolton, Harvey, Jr.

    2006-06-01

    This project integrates three distinct goals to develop a fundamental understanding of the potential fate and disposition of plutonium in sediments that are co-contaminated with EDTA. The three objectives are: (1) Develop thermodynamic data for Pu-EDTA species and determine the dominant mobile form of Pu under anaerobic conditions. (2) Elucidate the mechanism and rates of Pu(IV) and Pu(IV)-EDTA reduction by metal-reducing bacteria and determine where the Pu is located (in solution, biosorbed, bioaccumulated). (3) Enrich and isolate anaerobic EDTA-degrading microorganisms to investigate the anaerobic biodegradation of Pu-EDTA.

  15. Quantification of acidic compounds in complex biomass-derived streams

    SciTech Connect

    Karp, Eric M.; Nimlos, Claire T.; Deutch, Steve; Salvachúa, Davinia; Cywar, Robin M.; Beckham, Gregg T.

    2016-01-01

    Biomass-derived streams that contain acidic compounds from the degradation of lignin and polysaccharides (e.g. black liquor, pyrolysis oil, pyrolytic lignin, etc.) are chemically complex solutions prone to instability and degradation during analysis, making quantification of compounds within them challenging. Here we present a robust analytical method to quantify acidic compounds in complex biomass-derived mixtures using ion exchange, sample reconstitution in pyridine and derivatization with BSTFA. The procedure is based on an earlier method originally reported for kraft black liquors and, in this work, is applied to identify and quantify a large slate of acidic compounds in corn stover derived alkaline pretreatment liquor (APL) as a function of pretreatment severity. Analysis of the samples is conducted with GCxGC-TOFMS to achieve good resolution of the components within the complex mixture. The results reveal the dominant low molecular weight components and their concentrations as a function of pretreatment severity. Application of this method is also demonstrated in the context of lignin conversion technologies by applying it to track the microbial conversion of an APL substrate. Here too excellent results are achieved, and the appearance and disappearance of compounds is observed in agreement with the known metabolic pathways of two bacteria, indicating the sample integrity was maintained throughout analysis. Finally, it is shown that this method applies more generally to lignin-rich materials by demonstrating its usefulness in analysis of pyrolysis oil and pyrolytic lignin.

  16. Synergetic effects of DA-6/GA₃ with EDTA on plant growth, extraction and detoxification of Cd by Lolium perenne.

    PubMed

    He, Shanying; Wu, Qiuling; He, Zhenli

    2014-12-01

    Research is needed to improve efficiency of phytoextraction of heavy metals from contaminated soils. A pot experiment was carried out to study the effects of plant growth regulators (PGRs) (diethyl aminoethyl hexanoate (C18H33NO8, DA-6) and gibberellic acid 3 (C19H22O6, GA3)) and/or EDTA on Cd extraction, subcellular distribution and chemical forms in Lolium perenne. The addition of EDTA or PGRs significantly enhanced Cd extraction efficiency (P<0.05), with the decreasing order of: 1 μM DA-6>10 μM DA-6>10 μM GA3>2.5 mmol kg(-1) EDTA>other treatments of PGR alone. PGRs+EDTA resulted in a further increase in Cd extraction efficiency, with EDTA+1 μM DA-6 being the most efficient. At the subcellular level, about 44-57% of Cd was soluble fraction, 18-44% in cell walls, and 12-25% in cellular organelles fraction. Chemical speciation analysis showed that 40-54% of Cd was NaCl extractable, 7-23% HAc extractable, followed by other fractions. EDTA increased the proportions of Cd in soluble and cellular organelles fraction, as well as the metal migration in shoot; therefore, the toxicity to plant increased and plant growth was inhibited. Conversely, PGRs fixed more Cd in cell walls and reduced Cd migration in shoot; thus, metal toxicity was reduced. In addition, PGRs promoted plant biomass growth significantly (P<0.05), with 1 μM DA-6 being the most effective. A combination of DA-6/GA3 with EDTA can alleviate the adverse effect of EDTA on plant growth, and the treatment of EDTA+1 μM DA-6 appears to be optimal for improving the remediation efficiency of L. perenne for Cd contaminated soil. PMID:24999226

  17. Redistribution of fractions of zinc, cadmium, nickel, copper, and lead in contaminated calcareous soils treated with EDTA.

    PubMed

    Jalali, Mohsen; Khanlari, Zahra V

    2007-11-01

    Effect of ethylene diamine tetraacetic acid (EDTA) on the fractionation of zinc (Zn), cadmium (Cd), nickel (Ni), copper (Cu), and lead (Pb) in contaminated calcareous soils was investigated. Soil samples containing variable levels of contamination, from 105.9 to 5803 mg/kg Zn, from 2.2 to 1361 mg/kg Cd, from 31 to 64.0 mg/kg Ni, from 24 to 84 mg/kg Cu, and from 109 to 24,850 mg/kg Pb, were subjected to EDTA treatment at different dosages of 0, 1.0, and 2.0 g/kg. Metals in the incubated soils were fractionated after 5 months by a sequential extraction procedure, in which the metal fractions were experimentally defined as exchangeable (EXCH), carbonate (CARB), Mn oxide (MNO), Fe oxide (FEO), organic matter (OM), and residual (RES) fractions. In contaminated soils without EDTA addition, Zn, Ni, Cu, and Pb were predominately present in the RES fraction, up to 60.0%, 32.3%, 41.1%, and 36.8%, respectively. In general, with the EDTA addition, the EXCH and CARB fractions of these metals increased dramatically while the OM fraction decreased. The Zn, Ni, Cu, and Pb were distributed mostly in RES, OM, FEO, and CARB fractions in contaminated soils, but Cd was found predominately in the CARB, MNO, and RES fractions. The OM fraction decreased with increasing amounts of EDTA. In the contaminated soils, EDTA removed some Pb, Zn, Cu, and Ni from MNO, FEO, and OM fractions and redistributed them into CARB and EXCH fractions. Based on the relative percent in the EXCH and CARB fractions, the order of solubility was Cd > Pb > Ni > Cu > Zn for contaminated soils, before adding of EDTA, and after adding of EDTA, the order of solubility was Pb > Cd > Zn > Ni > Cu. The risk of groundwater contamination will increase after applying EDTA and it needed to be used very carefully.

  18. Synergetic effects of DA-6/GA₃ with EDTA on plant growth, extraction and detoxification of Cd by Lolium perenne.

    PubMed

    He, Shanying; Wu, Qiuling; He, Zhenli

    2014-12-01

    Research is needed to improve efficiency of phytoextraction of heavy metals from contaminated soils. A pot experiment was carried out to study the effects of plant growth regulators (PGRs) (diethyl aminoethyl hexanoate (C18H33NO8, DA-6) and gibberellic acid 3 (C19H22O6, GA3)) and/or EDTA on Cd extraction, subcellular distribution and chemical forms in Lolium perenne. The addition of EDTA or PGRs significantly enhanced Cd extraction efficiency (P<0.05), with the decreasing order of: 1 μM DA-6>10 μM DA-6>10 μM GA3>2.5 mmol kg(-1) EDTA>other treatments of PGR alone. PGRs+EDTA resulted in a further increase in Cd extraction efficiency, with EDTA+1 μM DA-6 being the most efficient. At the subcellular level, about 44-57% of Cd was soluble fraction, 18-44% in cell walls, and 12-25% in cellular organelles fraction. Chemical speciation analysis showed that 40-54% of Cd was NaCl extractable, 7-23% HAc extractable, followed by other fractions. EDTA increased the proportions of Cd in soluble and cellular organelles fraction, as well as the metal migration in shoot; therefore, the toxicity to plant increased and plant growth was inhibited. Conversely, PGRs fixed more Cd in cell walls and reduced Cd migration in shoot; thus, metal toxicity was reduced. In addition, PGRs promoted plant biomass growth significantly (P<0.05), with 1 μM DA-6 being the most effective. A combination of DA-6/GA3 with EDTA can alleviate the adverse effect of EDTA on plant growth, and the treatment of EDTA+1 μM DA-6 appears to be optimal for improving the remediation efficiency of L. perenne for Cd contaminated soil.

  19. A chemical kinetic model for NO sub x removal in an aqueous scrubber system using the additive Fe(II)ter dot EDTA

    SciTech Connect

    Mendelsohn, M.H.; Livengood, C.D.

    1992-01-01

    Addition of the metal chelate, ferrous{center dot} ethylenediaminetetraacetate anion (Fe(II){center dot}EDTA{sup 2{minus}}), has been shown to increase the amount of gaseous nitrogen oxides absorbed from a gas stream containing sulfur dioxide, where an aqueous scrubbing process is used to treat the gas. Recently, we published data on improved systems for NO{sub x} removal that incorporate an antioxidant and/or reducing agent (A/R) in the process along with the Fe(H){center dot}EDTA. The purpose of the A/R is to maintain the highest possible concentration of iron in the +2 form. The major mechanism for NO removal is believed to be the equilibrium reaction of Fe(II){center dot}EDTA with dissolved NO to form a Fe(II){center dot}EDTA{center dot}NO complex. It has been shown that both sulfite and bisulfite anions can react with Fe(II){center dot}EDTA{center dot}NO to regenerate Fe(II){center dot}EDTA and other products. In a complex system, other oxidation and reduction mechanisms are also possible. We have chosen, therefore, to approach this problem empirically by fitting our experimental data to a model containing at most three kinetic terms, chosen from among the following: a baseline removal rate, which is equivalent to the rate of reaction of Fe(II){center dot}EDTA with nitric oxide; a regeneration rate, which is equivalent to decomposition of the Fe(II){center dot}EDTA{center dot}NO complex to Fe(II){center dot}EDTA; an oxidation rate, which is a combined rate for all possible oxidation reactions involving Fe(II){center dot}EDTA; and a reduction rate, which is a combined rate for all possible reduction reactions involving ferric-EDTA in the system.

  20. A chemical kinetic model for NO{sub x} removal in an aqueous scrubber system using the additive Fe[II]{center_dot}EDTA

    SciTech Connect

    Mendelsohn, M.H.; Livengood, C.D.

    1992-09-01

    Addition of the metal chelate, ferrous{center_dot} ethylenediaminetetraacetate anion (Fe[II]{center_dot}EDTA{sup 2{minus}}), has been shown to increase the amount of gaseous nitrogen oxides absorbed from a gas stream containing sulfur dioxide, where an aqueous scrubbing process is used to treat the gas. Recently, we published data on improved systems for NO{sub x} removal that incorporate an antioxidant and/or reducing agent (A/R) in the process along with the Fe[H]{center_dot}EDTA. The purpose of the A/R is to maintain the highest possible concentration of iron in the +2 form. The major mechanism for NO removal is believed to be the equilibrium reaction of Fe[II]{center_dot}EDTA with dissolved NO to form a Fe[II]{center_dot}EDTA{center_dot}NO complex. It has been shown that both sulfite and bisulfite anions can react with Fe[II]{center_dot}EDTA{center_dot}NO to regenerate Fe[II]{center_dot}EDTA and other products. In a complex system, other oxidation and reduction mechanisms are also possible. We have chosen, therefore, to approach this problem empirically by fitting our experimental data to a model containing at most three kinetic terms, chosen from among the following: a baseline removal rate, which is equivalent to the rate of reaction of Fe[II]{center_dot}EDTA with nitric oxide; a regeneration rate, which is equivalent to decomposition of the Fe[II]{center_dot}EDTA{center_dot}NO complex to Fe[II]{center_dot}EDTA; an oxidation rate, which is a combined rate for all possible oxidation reactions involving Fe[II]{center_dot}EDTA; and a reduction rate, which is a combined rate for all possible reduction reactions involving ferric-EDTA in the system.

  1. Estimating the acidity of transition metal hydride and dihydrogen complexes by adding ligand acidity constants.

    PubMed

    Morris, Robert H

    2014-02-01

    A simple equation (pKa(THF) = ∑AL + Ccharge + Cnd + Cd6) can be used to obtain an estimate of the pKa of diamagnetic transition metal hydride and dihydrogen complexes in tetrahydrofuran, and, by use of conversion equations, in other solvents. It involves adding acidity constants AL for each of the ligands in the 5-, 6-, 7-, or 8-coordinate conjugate base complex of the hydride or dihydrogen complex along with a correction for the charge (Ccharge = -15, 0 or 30 for x = +1, 0 or -1 charge, respectively) and the periodic row of the transition metal (Cnd = 0 for 3d or 4d metal, 2 for 5d metal) as well as a correction for d(6) octahedral acids (Cd6 = 6 for d(6) metal ion in the acid, 0 for others) that are not dihydrogen complexes. Constants AL are provided for 13 commonly occurring ligand types; of these, nine neutral ligands are correlated with Lever's electrochemical ligand parameters EL. This method gives good estimates of the over 170 literature pKa values that range from less than zero to 50 with a standard deviation of 3 pKa units for complexes of the metals chromium to nickel, molybdenum, ruthenium to palladium, and tungsten to platinum in the periodic table. This approach allows a quick assessment of the acidity of hydride complexes found in nature (e.g., hydrogenases) and in industry (e.g., catalysis and hydrogen energy applications). The pKa values calculated for acids that have bulky or large bite angle chelating ligands deviate the most from this correlation. The method also provides an estimate of the base strength of the deprotonated form of the complex.

  2. Estimating the acidity of transition metal hydride and dihydrogen complexes by adding ligand acidity constants.

    PubMed

    Morris, Robert H

    2014-02-01

    A simple equation (pKa(THF) = ∑AL + Ccharge + Cnd + Cd6) can be used to obtain an estimate of the pKa of diamagnetic transition metal hydride and dihydrogen complexes in tetrahydrofuran, and, by use of conversion equations, in other solvents. It involves adding acidity constants AL for each of the ligands in the 5-, 6-, 7-, or 8-coordinate conjugate base complex of the hydride or dihydrogen complex along with a correction for the charge (Ccharge = -15, 0 or 30 for x = +1, 0 or -1 charge, respectively) and the periodic row of the transition metal (Cnd = 0 for 3d or 4d metal, 2 for 5d metal) as well as a correction for d(6) octahedral acids (Cd6 = 6 for d(6) metal ion in the acid, 0 for others) that are not dihydrogen complexes. Constants AL are provided for 13 commonly occurring ligand types; of these, nine neutral ligands are correlated with Lever's electrochemical ligand parameters EL. This method gives good estimates of the over 170 literature pKa values that range from less than zero to 50 with a standard deviation of 3 pKa units for complexes of the metals chromium to nickel, molybdenum, ruthenium to palladium, and tungsten to platinum in the periodic table. This approach allows a quick assessment of the acidity of hydride complexes found in nature (e.g., hydrogenases) and in industry (e.g., catalysis and hydrogen energy applications). The pKa values calculated for acids that have bulky or large bite angle chelating ligands deviate the most from this correlation. The method also provides an estimate of the base strength of the deprotonated form of the complex. PMID:24410025

  3. Observation of unusual slow-relaxation of the magnetisation in a Gd-EDTA chelate.

    PubMed

    Holmberg, Rebecca J; Ho, Le Tuan Anh; Ungur, Liviu; Korobkov, Ilia; Chibotaru, Liviu F; Murugesu, Muralee

    2015-12-21

    A Gadolinium EDTA chelate displays characteristic isotropic behaviour common of Gd(III) complexes under zero applied magnetic field, and anisotropic behaviour arising from dipolar coupling and weak spin-phonon coupling under an applied magnetic field. This surprising magnetic behaviour for Gd(III) is investigated using SQUID magnetometry and rationalized through theoretical calculations.

  4. Complexes of polyadenylic acid and the methyl esters of amino acids

    NASA Technical Reports Server (NTRS)

    Khaled, M. A.; Mulins, D. W., Jr.; Swindle, M.; Lacey, J. C., Jr.

    1983-01-01

    A study of amino acid methyl esters binding to polyadenylic acid supports the theory that the genetic code originated through weak but selective affinities between amino acids and nucleotides. NMR, insoluble complex analysis, and ultraviolet spectroscopy are used to illustrate a correlation between the hydrophybicities of A amino acids and their binding constants, which, beginning with the largest, are in the order of Phe (having nominally a hydrophobic AAA anticodon), Ile, Leu, Val and Gly (having a hydrophilic anticodon with no A). In general, the binding constants are twice the values by Reuben and Polk (1980) for monomeric AMP, which suggests that polymer amino acids are interacting with only one base. No real differences are found betwen poly A binding for free Phe, Phe methyl ester or Phe amide, except that the amide value is slightly lower.

  5. Flow Cytometry Method Analysis of Apoptosis: No Significant Difference Between EDTA and EDTA-free Trypsin Treatment Procedure.

    PubMed

    Xu, Xiao-yan; Nie, Xiao-cui; Ma, Hai-ying; Song, Guo-qing; Zhang, Xiao-tong; Jin, Yu-nan; Yu, Yan-qiu

    2015-04-01

    Flow cytometry method (FCM) is a generally accepted tool to analyze apoptosis. Although apoptosis assay kit was applied by many companies, the manufacturers were not consistent with whether using Trypsin with EDTA to collect the adherent cells. In another words, the influence of EDTA on apoptotic ratio is not clear. In this work, we compared the proportion of apoptotic cells with EDTA or EDTA-free Trypsin treatment by FCM. We concluded that Trypsin with or without EDTA has little influence on the proportion of apoptotic cells. In addition, we found that the ratio of necrosis and apoptosis was different in cells collected by scraping. WAVE2 protein was analyzed as a typical example for movement related protein. WAVE2 expression is elevated in the EDTA Trypsin treated group, compared with EDTA-free Trypsin treatment and scrapping group.

  6. Biomonitoring acidic drainage impact in a complex setting using periphyton.

    PubMed

    de la Peña, Santiago; Barreiro, Rodolfo

    2009-03-01

    Acid mine drainage (AMD) often exerts various environmental pressures on nearby water courses: chemical stress from low pH and dissolved metals; physical stress from metal oxide deposits. Affected streams can thus display a spatially variable combination of stress agents that may complicate its biomonitoring using native communities such as periphyton. Here, we have measured water and periphyton variables in four streams that surround an abandoned copper mine to determine which periphyton attributes consistently detected AMD impact in a complex environmental setting. Seventeen years after the end of commercial exploitation, the abandoned mine still decreases water quality in nearby streams: moderate acidification, very high metal load (Al, Ni, Cu, Zn), and a conspicuous presence of metal oxide deposits with diverse composition. Even under the resultant complex pattern of polluted conditions, periphyton was a reliable bioindicator of AMD. Epilithic diatom taxa tolerant of acidic conditions increased in AMD sites and, at severely impacted locations, species richness decreased. Also, algal biomass may have been negatively affected in some stream reaches affected by metal oxide deposits. Other periphyton attributes (total biomass, diatom diversity) seemed mostly unrelated to AMD. Diatom assemblage composition was the most sensitive and consistent bioindicator of mine drainage; besides, it rendered a biological assessment of AMD impact that largely coincided with the physicochemical evaluation. Still, including other taxonomic (proportion of acid-tolerant diatom species, diatom richness) and non-taxonomic (algal biomass) attributes in the biomonitoring procedure rendered a more comprehensive assessment of the negative consequences generated by AMD.

  7. Complexes of carborane acids linked by strong hydrogen bonds: acidity scales.

    PubMed

    Grabowski, Sławomir J

    2016-06-28

    Carborane acids, currently known as the strongest acis, are analyzed and compared with other species classified as superacids as well as with selected mineral acids and carbocations. Calculations (B3LYP/6-311++G(d,p) level) on these moieties as well as on their conjugate bases were performed to evaluate corresponding proton affinities. In addition, the complexes of these species with the CHB11F11(-) anion and the complexes of the conjugate bases with the trimethylammonium cation were analyzed. The scales, based on spectroscopic results, DFT energies and on the topological QTAIM (Quantum Theory of Atoms in Molecules) parameters, are introduced and discussed to order the acidity of the species analyzed here. The properties of the bond critical points corresponding to the intermolecular contacts are discussed. The majority of the results show that HCHB11F11 carborane acid is the strongest in agreement with the previous experimental studies of Reed and coworkers. Very often the abovementioned acidity scales show that carborane acids are able to protonate hydrocarbons. PMID:27253195

  8. Oxygenation of Organoboronic Acids by a Nonheme Iron(II) Complex: Mimicking Boronic Acid Monooxygenase Activity.

    PubMed

    Chatterjee, Sayanti; Paine, Tapan Kanti

    2015-10-19

    Phenolic compounds are important intermediates in the bacterial biodegradation of aromatic compounds in the soil. An Arthrobacter sp. strain has been shown to exhibit boronic acid monooxygenase activity through the conversion of different substituted phenylboronic acids to the corresponding phenols using dioxygen. While a number of methods have been reported to cleave the C-B bonds of organoboronic acids, there is no report on biomimetic iron complex exhibiting this activity using dioxygen as the oxidant. In that direction, we have investigated the reactivity of a nucleophilic iron-oxygen oxidant, generated upon oxidative decarboxylation of an iron(II)-benzilate complex [(Tp(Ph2))Fe(II)(benzilate)] (Tp(Ph2) = hydrotris(3,5-diphenyl-pyrazol-1-yl)borate), toward organoboronic acids. The oxidant converts different aryl/alkylboronic acids to the corresponding oxygenated products with the incorporation of one oxygen atom from dioxygen. This method represents an efficient protocol for the oxygenation of boronic acids with dioxygen as the terminal oxidant.

  9. Complexes of carborane acids linked by strong hydrogen bonds: acidity scales.

    PubMed

    Grabowski, Sławomir J

    2016-06-28

    Carborane acids, currently known as the strongest acis, are analyzed and compared with other species classified as superacids as well as with selected mineral acids and carbocations. Calculations (B3LYP/6-311++G(d,p) level) on these moieties as well as on their conjugate bases were performed to evaluate corresponding proton affinities. In addition, the complexes of these species with the CHB11F11(-) anion and the complexes of the conjugate bases with the trimethylammonium cation were analyzed. The scales, based on spectroscopic results, DFT energies and on the topological QTAIM (Quantum Theory of Atoms in Molecules) parameters, are introduced and discussed to order the acidity of the species analyzed here. The properties of the bond critical points corresponding to the intermolecular contacts are discussed. The majority of the results show that HCHB11F11 carborane acid is the strongest in agreement with the previous experimental studies of Reed and coworkers. Very often the abovementioned acidity scales show that carborane acids are able to protonate hydrocarbons.

  10. Oxygenation of Organoboronic Acids by a Nonheme Iron(II) Complex: Mimicking Boronic Acid Monooxygenase Activity.

    PubMed

    Chatterjee, Sayanti; Paine, Tapan Kanti

    2015-10-19

    Phenolic compounds are important intermediates in the bacterial biodegradation of aromatic compounds in the soil. An Arthrobacter sp. strain has been shown to exhibit boronic acid monooxygenase activity through the conversion of different substituted phenylboronic acids to the corresponding phenols using dioxygen. While a number of methods have been reported to cleave the C-B bonds of organoboronic acids, there is no report on biomimetic iron complex exhibiting this activity using dioxygen as the oxidant. In that direction, we have investigated the reactivity of a nucleophilic iron-oxygen oxidant, generated upon oxidative decarboxylation of an iron(II)-benzilate complex [(Tp(Ph2))Fe(II)(benzilate)] (Tp(Ph2) = hydrotris(3,5-diphenyl-pyrazol-1-yl)borate), toward organoboronic acids. The oxidant converts different aryl/alkylboronic acids to the corresponding oxygenated products with the incorporation of one oxygen atom from dioxygen. This method represents an efficient protocol for the oxygenation of boronic acids with dioxygen as the terminal oxidant. PMID:26430780

  11. EDTA enhanced plant growth, antioxidant defense system, and phytoextraction of copper by Brassica napus L.

    PubMed

    Habiba, Ume; Ali, Shafaqat; Farid, Mujahid; Shakoor, Muhammad Bilal; Rizwan, Muhammad; Ibrahim, Muhammad; Abbasi, Ghulam Hasan; Hayat, Tahir; Ali, Basharat

    2015-01-01

    Copper (Cu) is an essential micronutrient for normal plant growth and development, but in excess, it is also toxic to plants. The present study investigated the influence of ethylenediaminetetraacetic acid (EDTA) in enhancing Cu uptake and tolerance as well as the morphological and physiological responses of Brassica napus L. seedlings under Cu stress. Four-week-old seedlings were transferred to hydroponics containing Hoagland's nutrient solution. After 2 weeks of transplanting, three levels (0, 50, and 100 μM) of Cu were applied with or without application of 2.5 mM EDTA and plants were further grown for 8 weeks in culture media. Results showed that Cu alone significantly decreased plant growth, biomass, photosynthetic pigments, and gas exchange characteristics. Cu stress also reduced the activities of antioxidants, such as superoxide dismutase (SOD), peroxidase (POD), ascorbate peroxidase (APX), and catalase (CAT) along with protein contents. Cu toxicity increased the concentration of reactive oxygen species (ROS) as indicated by the increased production of malondialdehyde (MDA) and hydrogen peroxide (H2O2) in both leaves and roots. The application of EDTA significantly alleviated Cu-induced toxic effects in B. napus, showing remarkable improvement in all these parameters. EDTA amendment increased the activity of antioxidant enzymes by decreasing the concentrations of MDA and H2O2 both in leaves and roots of B. napus. Although, EDTA amendment with Cu significantly increased Cu uptake in roots, stems, and leaves in decreasing order of concentration but increased the growth, photosynthetic parameters, and antioxidant enzymes. These results showed that the application of EDTA can be a useful strategy for phytoextraction of Cu by B. napus from contaminated soils. PMID:25163559

  12. Combined Effect of Trolox and EDTA on Frozen-Thawed Sperm Quality

    PubMed Central

    Keshtgar, Sara; Iravanpour, Farideh; Gharesi-Fard, Behrooz; Kazerooni, Marjaneh

    2016-01-01

    The freezing and thawing process not only is associated with serious damage to sperm such as damage to the plasma membrane and the acrosomal membrane but also changes the membrane permeability to some ions including calcium. Also, the generation of oxygen free radicals is increased during the freezing-thawing process. The purpose of this study was to evaluate of the effects of Trolox as an antioxidant and edetic acid (EDTA) as a calcium chelator on frozen-thawed (FT) sperm and compare these effects with those on fresh sperm. This study was done on these men of 25 healthy men, who referred to Shiraz Infertility Centerbetween2012 and2013. Normal samples were transferred to the ReproductivePhysiology Laboratory, Department of Physiology, Shiraz University of Medical Sciences, Shiraz. The samples were divided into two groups randomly: fresh and FT sperm groups. Each group was divided into five subgroups: control group, the solvent group (0.1%dimethyl sulfoxide [DMSO]), Trolox group (200μM), EDTA group (1.1mM), and Trolox+EDTA group. The percentages of motility, viability, and acrosome-reacted sperm were tested. The percentages of motility and viability in the FT sperm were lower than those in the fresh sperm. The progressive motility of the FT sperm was improved nonsignificantly with Trolox+EDTA. However, the effect of Trolox+EDTA on the progressive motility of the FT sperm was much more than that on the fresh sperm. The fewest acrosome-reacted sperm were observed in the EDTA-containingFT sperm. Antioxidant supplementation or omission of extracellular calcium may partly improve motility and also reduce acrosomal damage in FT sperm. PMID:27217608

  13. EDTA enhanced plant growth, antioxidant defense system, and phytoextraction of copper by Brassica napus L.

    PubMed

    Habiba, Ume; Ali, Shafaqat; Farid, Mujahid; Shakoor, Muhammad Bilal; Rizwan, Muhammad; Ibrahim, Muhammad; Abbasi, Ghulam Hasan; Hayat, Tahir; Ali, Basharat

    2015-01-01

    Copper (Cu) is an essential micronutrient for normal plant growth and development, but in excess, it is also toxic to plants. The present study investigated the influence of ethylenediaminetetraacetic acid (EDTA) in enhancing Cu uptake and tolerance as well as the morphological and physiological responses of Brassica napus L. seedlings under Cu stress. Four-week-old seedlings were transferred to hydroponics containing Hoagland's nutrient solution. After 2 weeks of transplanting, three levels (0, 50, and 100 μM) of Cu were applied with or without application of 2.5 mM EDTA and plants were further grown for 8 weeks in culture media. Results showed that Cu alone significantly decreased plant growth, biomass, photosynthetic pigments, and gas exchange characteristics. Cu stress also reduced the activities of antioxidants, such as superoxide dismutase (SOD), peroxidase (POD), ascorbate peroxidase (APX), and catalase (CAT) along with protein contents. Cu toxicity increased the concentration of reactive oxygen species (ROS) as indicated by the increased production of malondialdehyde (MDA) and hydrogen peroxide (H2O2) in both leaves and roots. The application of EDTA significantly alleviated Cu-induced toxic effects in B. napus, showing remarkable improvement in all these parameters. EDTA amendment increased the activity of antioxidant enzymes by decreasing the concentrations of MDA and H2O2 both in leaves and roots of B. napus. Although, EDTA amendment with Cu significantly increased Cu uptake in roots, stems, and leaves in decreasing order of concentration but increased the growth, photosynthetic parameters, and antioxidant enzymes. These results showed that the application of EDTA can be a useful strategy for phytoextraction of Cu by B. napus from contaminated soils.

  14. Concomitant spuriously elevated white blood cell count, a previously underestimated phenomenon in EDTA-dependent pseudothrombocytopenia.

    PubMed

    Xiao, Yufei; Xu, Yang

    2015-01-01

    The proportion and potential risk of concomitant spuriously elevated white blood cell count (SEWC) are underestimated in ethylenediaminetetraacetic acid (EDTA)-dependent pseudothrombocytopenia (PTCP). The proportion, kinetics and prevention of SEWC remain poorly understood. A total of 25 patients with EDTA-dependent PTCP were enrolled in this study. With the hematology analyzer Coulter LH 750, we determined the time courses of WBC count, WBC differential and platelet count in EDTA- and sodium citrate-anticoagulated blood, respectively. Blood smears were prepared to inspect the presence of platelet clumps using light microscopy. The effect of automatic instrumental correction on the extent of SEWC was evaluated. The proportion of SEWC was 92% in EDTA-dependent PTCP and 73.9% of SEWCs were within the normal range. The development of SEWC was time-dependent, and neutrophils and lymphocytes were the main subpopulations involved in SEWC. A strong and significant correlation (r = 0.9937, p < 0.001) was found between the increased WBC count and the decreased platelet count. Both corrected and uncorrected WBC counts at 15 minutes or later after blood collection in EDTA were significantly higher than their basal counts, respectively, p < 0.05. Interestingly, in citrated blood, WBC counts after blood collection were not significantly different from its basal counts, p > 0.05. A high proportion of concomitant SEWCs, which are mainly within normal range, are present in patients with EDTA-dependent PTCP. Proper interpretation of SEWC is crucial to avoid clinic errors. SEWC develops in a time-dependent pattern, although the Coulter LH 750 only partly mitigates the extent of SEWC, sodium citrate is able to effectively prevent SEWC.

  15. Plasma Amino Acids Changes in Complex Regional Pain Syndrome

    PubMed Central

    Alexander, Guillermo M.; Reichenberger, Erin; Peterlin, B. Lee; Perreault, Marielle J.; Grothusen, John R.; Schwartzman, Robert J.

    2013-01-01

    Complex regional pain syndrome (CRPS) is a severe chronic pain condition that most often develops following trauma. Blood samples were collected from 220 individuals, 160 CRPS subjects, and 60 healthy pain-free controls. Plasma amino acid levels were compared and contrasted between groups. L-Aspartate, L-glutamate, and L-ornithine were significantly increased, whereas L-tryptophan and L-arginine were significantly decreased in CRPS subjects as compared to controls. In addition, the L-kynurenine to L-tryptophan ratio demonstrated a significant increase, whereas the global arginine bioavailability ratio (GABR) was significantly decreased in the CRPS subjects. The CRPS subjects demonstrated a significant correlation between overall pain and the plasma levels of L-glutamate and the L-kynurenine to L-tryptophan ratio. CRPS subjects also showed a correlation between the decrease in plasma L-tryptophan and disease duration. This study shows that CRPS subjects exhibit significant changes in plasma levels of amino acids involved in glutamate receptor activation and in amino acids associated with immune function as compared to healthy pain-free controls. A better understanding of the role plasma amino acids play in the pathophysiology of CRPS may lead to novel treatments for this crippling condition. PMID:24303215

  16. [PREPARATIONS OF PAMIDRONOVIC ACID IN COMPLEX TREATMENT ON OSTEOGENESIS IMPERFECTA].

    PubMed

    Zyma, A M; Guk, Yu M; Magomedov, O M; Gayko, O G; Kincha-Polishchuk, T A

    2015-07-01

    Modern view of drug therapy in the complex treatment of orthopedic manifestations of osteogenesis imperfecta (OI) was submitted. Developed and tested system of drug correction of structural and functional state of bone tissue (BT) using drugs pamidronovic acid, depending on osteoporosis severity and type of disease. Such therapy is appropriate to apply both independently and in conjunction with surgery to correct deformations of long bones of the lower extremities. Effectiveness and feasibility of the proposed methods of drug therapy was proved, most patients resume features walking and support. PMID:26591224

  17. Structure and function analysis of protein-nucleic acid complexes

    NASA Astrophysics Data System (ADS)

    Kuznetsova, S. A.; Oretskaya, T. S.

    2016-05-01

    The review summarizes published data on the results and achievements in the field of structure and function analysis of protein-nucleic acid complexes by means of main physical and biochemical methods, including X-ray diffraction, nuclear magnetic resonance spectroscopy, electron and atomic force microscopy, small-angle X-ray and neutron scattering, footprinting and cross-linking. Special attention is given to combined approaches. The advantages and limitations of each method are considered, and the prospects of their application for wide-scale structural studies in vivo are discussed. The bibliography includes 145 references.

  18. Structure and function analysis of protein–nucleic acid complexes

    NASA Astrophysics Data System (ADS)

    Kuznetsova, S. A.; Oretskaya, T. S.

    2016-05-01

    The review summarizes published data on the results and achievements in the field of structure and function analysis of protein–nucleic acid complexes by means of main physical and biochemical methods, including X-ray diffraction, nuclear magnetic resonance spectroscopy, electron and atomic force microscopy, small-angle X-ray and neutron scattering, footprinting and cross-linking. Special attention is given to combined approaches. The advantages and limitations of each method are considered, and the prospects of their application for wide-scale structural studies in vivo are discussed. The bibliography includes 145 references.

  19. Formation and characterization of thioglycolic acid-silver cluster complexes.

    PubMed

    Bellina, Bruno; Antoine, Rodolphe; Broyer, Michel; Gell, Lars; Sanader, Željka; Mitrić, Roland; Bonačić-Koutecký, Vlasta; Dugourd, Philippe

    2013-06-21

    Gas phase reactivity observed in an ion trap was used to produce silver clusters protected with thioglycolic acid. Fragmentation pathways as well as optical properties were explored experimentally and theoretically. Sequential losses of SCH2 and CO2 in the ion trap lead to redox reactions with charge transfers between the metal part and the carboxylate and thiolate groups. This allows us to control the number of electrons in the metallic subunit and thus optical properties of the complexes. The presented formation process can be used as a prototype for tuning optical and chemical properties of ligated metal clusters by varying the number of confined electrons within the metallic subunit.

  20. Process dependent thermoelectric properties of EDTA assisted bismuth telluride

    NASA Astrophysics Data System (ADS)

    Kulsi, Chiranjit; Kargupta, Kajari; Banerjee, Dipali

    2016-04-01

    Comparison between the structure and thermoelectric properties of EDTA (Ethylene-diamine-tetra-acetic acid) assisted bismuth telluride prepared by electrochemical deposition and hydrothermal route is reported in the present work. The prepared samples have been structurally characterized by high resolution X-ray diffraction spectra (HRXRD), field emission scanning electron microscopy (FESEM) and high resolution transmission electron microscopic images (HRTEM). Crystallite size and strain have been determined from Williamson-Hall plot of XRD which is in conformity with TEM images. Measurement of transport properties show sample in the pellet form (S1) prepared via hydrothermal route has higher value of thermoelectric power (S) than the electrodeposited film (S2). But due to a substantial increase in the electrical conductivity (σ) of the film (S2) over the pellet (S1), the power factor and the figure of merit is higher for sample S2 than the sample S1 at room temperature.

  1. The complexation behavior of neptunium and plutonium with nitrilotriacetic acid

    SciTech Connect

    Nitsche, H.; Becraft, K.

    1990-08-01

    The first stability constant of NpO{sub 2}{sup +} with nitrilotriacetic acid (NTA) was determined at four ionic strengths (0.5, 1.0, 2.0, 3.0 M) using spectrophotometry. Nonlinear least-squares data fitting identified the complex as NpO{sub 2}NTA{sup 2-}. The Specific Ion Interaction Theory (S.I.T) approximation method was used to determine the stability constants at infinite dilution. First results on Pu{sup 4+} and PuO{sub 2}{sup 2+} complexation with NTA are reported. The stability constant for the Pu(NTA){sup +} complex at I = 0.1 M strength is given. From results for PuO{sub 2}{sup 2+} complexation with NTA (I = 1 M) at pH < 3, the stability constant was derived for PuO{sub 2} NTA{sup {minus}}. At pH > 3, NTA partially reduced PuO{sub 2}{sup 2+} to PuO{sub 2}{sup +}. 3 refs., 5 figs., 4 tabs.

  2. M[superscript 2+]•EDTA Binding Affinities: A Modern Experiment in Thermodynamics for the Physical Chemistry Laboratory

    ERIC Educational Resources Information Center

    O'Brien, Leah C.; Root, Hannah B.; Wei, Chin-Chuan; Jensen, Drake; Shabestary, Nahid; De Meo, Cristina; Eder, Douglas J.

    2015-01-01

    Isothermal titration calorimetry was used to experimentally determine thermodynamic values for the ethylenediaminetetraacetic acid (EDTA)(aq) + M[superscript 2+](aq) reactions (M[superscript 2+] = Ca[superscript 2+] and Mg[superscript 2+]). Students showed that for reactions in a N-(2-hydroxyethyl)piperazine-N"-ethanesulfonic acid (HEPES)…

  3. EDTA leaching of Cu contaminated soil using electrochemical treatment of the washing solution.

    PubMed

    Pociecha, Maja; Lestan, Domen

    2009-06-15

    The feasibility of a two-phase method for remediation of Cu (364+/-2 mg kg(-1)) contaminated vineyard soil was evaluated. In the first phase we used ethylenediamine tetraacetae (EDTA) for Cu leaching, while in the second phase we used an electrochemical advanced oxidation process (EAOP) for the treatment and reuse of the washing solution for soil rinsing (removal of soil-retained, chelant-mobilized Cu complexes) in a closed loop. In the EAOP, a boron-doped diamond anode was used for the generation of hydroxyl radicals and oxidative decomposition of EDTA-metal complexes at a constant current density (40 mA cm(-2)). The released Cu was removed from the solution mostly as an electro-deposit on the cathode. Two consecutive additions of 10 mmol kg(-1) EDTA removed 26% of Cu from the soil, mostly from carbonate and oxide soil fractions (58% and 40% Cu reduction). The soil Cu oral availability (in vitro Physiologically Based Extraction Test) was reduced after remediation by 42% and 51% in the simulated stomach and intestinal phases. The discharge solution was clear, almost colorless, with pH 8.4 and 0.5 mg L(-1) Cu and 0.07 mM EDTA. The novel method enables soil Cu availability stripping using small volumes of process waters, and no wastewater generation or other emissions into the environment. PMID:19022571

  4. EDTA functionalized silica for removal of Cu(II), Zn(II) and Ni(II) from aqueous solution.

    PubMed

    Kumar, R; Barakat, M A; Daza, Y A; Woodcock, H L; Kuhn, J N

    2013-10-15

    Ethylenediaminetetraacetic acid (EDTA) functionalized silica adsorbent has been synthesized using (3-aminopropyl) triethoxylsilane (APTES) as a bridging link between silanol groups (SiOH) of silica and carboxylic group of EDTA. Fourier transform infrared spectroscopy (FTIR) and Temperature-programmed oxidation (TPO) analysis confirmed the grafting of EDTA onto the silica. The synthesized EDTA-silica was investigated as an adsorbent for removal of Cu(II), Zn(II) and Ni(II) from aqueous solution. The effect of solution pH, initial solution concentration, and contact time were studied. The removal of metal ions increased with the increase in solution pH, contact time and concentration. The maximum equilibrium time was found to be 45min for all three metal ions. Kinetics studies revealed that the adsorption of Cu(II), Zn(II) and Ni(II) onto EDTA-silica followed the pseudo-second order kinetics and film diffusion and intra-particle diffusion mechanism were involved. Adsorption equilibrium data were well fitted to Langmuir isotherm model and maximum monolayer adsorption capacity for Cu(II), Zn(II) and Ni(II) was 79.36, 74.07 and 67.56mg g(-1), respectively. Thermodynamic results reveal that the removal of metals onto EDTA-silica was endothermic and spontaneous in nature.

  5. Removal of acidic or basic α-amino acids in water by poorly water soluble scandium complexes.

    PubMed

    Hayashi, Nobuyuki; Jin, Shigeki; Ujihara, Tomomi

    2012-11-01

    To recognize α-amino acids with highly polar side chains in water, poorly water soluble scandium complexes with both Lewis acidic and basic portions were synthesized as artificial receptors. A suspension of some of these receptor molecules in an α-amino acid solution could remove acidic and basic α-amino acids from the solution. The compound most efficient at preferentially removing basic α-amino acids (arginine, histidine, and lysine) was the receptor with 7,7'-[1,3-phenylenebis(carbonylimino)]bis(2-naphthalenesulfonate) as the ligand. The neutral α-amino acids were barely removed by these receptors. Removal experiments using a mixed amino acid solution generally gave results similar to those obtained using solutions containing a single amino acid. The results demonstrated that the scandium complex receptors were useful for binding acidic and basic α-amino acids. PMID:23050492

  6. Removal of acidic or basic α-amino acids in water by poorly water soluble scandium complexes.

    PubMed

    Hayashi, Nobuyuki; Jin, Shigeki; Ujihara, Tomomi

    2012-11-01

    To recognize α-amino acids with highly polar side chains in water, poorly water soluble scandium complexes with both Lewis acidic and basic portions were synthesized as artificial receptors. A suspension of some of these receptor molecules in an α-amino acid solution could remove acidic and basic α-amino acids from the solution. The compound most efficient at preferentially removing basic α-amino acids (arginine, histidine, and lysine) was the receptor with 7,7'-[1,3-phenylenebis(carbonylimino)]bis(2-naphthalenesulfonate) as the ligand. The neutral α-amino acids were barely removed by these receptors. Removal experiments using a mixed amino acid solution generally gave results similar to those obtained using solutions containing a single amino acid. The results demonstrated that the scandium complex receptors were useful for binding acidic and basic α-amino acids.

  7. Simultaneously degradation of 2,4-dichlorophenol and EDTA in aqueous solution by the bimetallic Cu-Fe/O₂ system.

    PubMed

    Liu, Xin; Fan, Jin-Hong; Ma, Lu-Ming

    2015-01-01

    Oxidative degradation of aqueous organic contaminants 2,4-dichlorophenol (2,4-DCP) using ethylenediaminetetraacetic acid (EDTA)-enhanced bimetallic Cu-Fe system in the presence of dissolved oxygen was investigated. The proposed process was applied for the pH range of 3~7 with the degradation efficiency of 2,4-DCP and EDTA varying within 10 %, and achieved at 100 % degradation of 40 mg L(-1) 2,4-DCP in 1 h, at the initial pH of 3, 25 g L(-1) of bimetallic Fe-Cu powder (WCu/WFe = 0.01289) and initial EDTA of 0.57 mM. However, the removal efficiency of 2,4-DCP in control tests were 7.52 % (Cu-Fe/O2 system) and 84.32 % (EDTA-enhanced Fe/O2 process), respectively, after 3 h, reaction. The proposed main mechanism, involves the in situ generation of H2O2 by the electron transfer from Fe(0) to O2 which was enhanced by ethylenediaminetetraacetic acid (EDTA), and the in situ generation of ·OH via advanced oxidation reaction. Accordingly, 2,4-DCP was attacked by ·OH to achieve complete dechlorination and low molecular weight organic acids, even mineralized. Systematic studies on the effects of initial EDTA and 2,4-DCP concentration, Cu-Fe dosing, Cu content, and pH revealed that these effects need to be optimized to avoid the excessive consumption of ·OH and new EDTA and heavy metal Cu pollution.

  8. Dual Fatty Acid Elongase Complex Interactions in Arabidopsis.

    PubMed

    Morineau, Céline; Gissot, Lionel; Bellec, Yannick; Hematy, Kian; Tellier, Frédérique; Renne, Charlotte; Haslam, Richard; Beaudoin, Frédéric; Napier, Johnathan; Faure, Jean-Denis

    2016-01-01

    Very long chain fatty acids (VLCFAs) are involved in plant development and particularly in several cellular processes such as membrane trafficking, cell division and cell differentiation. However, the precise role of VLCFAs in these different cellular processes is still poorly understood in plants. In order to identify new factors associated with the biosynthesis or function of VLCFAs, a yeast multicopy suppressor screen was carried out in a yeast mutant strain defective for fatty acid elongation. Loss of function of the elongase 3 hydroxyacyl-CoA dehydratase PHS1 in yeast and PASTICCINO2 in plants prevents growth and induces cytokinesis defects. PROTEIN TYROSIN PHOSPHATASE-LIKE (PTPLA) previously characterized as an inactive dehydratase was able to restore yeast phs1 growth and VLCFAs elongation but not the plant pas2-1 defects. PTPLA interacted with elongase subunits in the Endoplasmic Reticulum (ER) and its absence induced the accumulation of 3-hydroxyacyl-CoA as expected from a dehydratase involved in fatty acid (FA) elongation. However, loss of PTPLA function increased VLCFA levels, an effect that was dependent on the presence of PAS2 indicating that PTPLA activity repressed FA elongation. The two dehydratases have specific expression profiles in the root with PAS2, mostly restricted to the endodermis, while PTPLA was confined in the vascular tissue and pericycle cells. Comparative ectopic expression of PTPLA and PAS2 in their respective domains confirmed the existence of two independent elongase complexes based on PAS2 or PTPLA dehydratase that are functionally interacting. PMID:27583779

  9. Dual Fatty Acid Elongase Complex Interactions in Arabidopsis

    PubMed Central

    Morineau, Céline; Gissot, Lionel; Bellec, Yannick; Hematy, Kian; Tellier, Frédérique; Renne, Charlotte; Haslam, Richard; Beaudoin, Frédéric; Napier, Johnathan; Faure, Jean-Denis

    2016-01-01

    Very long chain fatty acids (VLCFAs) are involved in plant development and particularly in several cellular processes such as membrane trafficking, cell division and cell differentiation. However, the precise role of VLCFAs in these different cellular processes is still poorly understood in plants. In order to identify new factors associated with the biosynthesis or function of VLCFAs, a yeast multicopy suppressor screen was carried out in a yeast mutant strain defective for fatty acid elongation. Loss of function of the elongase 3 hydroxyacyl-CoA dehydratase PHS1 in yeast and PASTICCINO2 in plants prevents growth and induces cytokinesis defects. PROTEIN TYROSIN PHOSPHATASE-LIKE (PTPLA) previously characterized as an inactive dehydratase was able to restore yeast phs1 growth and VLCFAs elongation but not the plant pas2-1 defects. PTPLA interacted with elongase subunits in the Endoplasmic Reticulum (ER) and its absence induced the accumulation of 3-hydroxyacyl-CoA as expected from a dehydratase involved in fatty acid (FA) elongation. However, loss of PTPLA function increased VLCFA levels, an effect that was dependent on the presence of PAS2 indicating that PTPLA activity repressed FA elongation. The two dehydratases have specific expression profiles in the root with PAS2, mostly restricted to the endodermis, while PTPLA was confined in the vascular tissue and pericycle cells. Comparative ectopic expression of PTPLA and PAS2 in their respective domains confirmed the existence of two independent elongase complexes based on PAS2 or PTPLA dehydratase that are functionally interacting. PMID:27583779

  10. Desorption of Hg(II) and Sb(V) on extracellular polymeric substances: effects of pH, EDTA, Ca(II) and temperature shocks.

    PubMed

    Zhang, Daoyong; Lee, Duu-Jong; Pan, Xiangliang

    2013-01-01

    Extracellular polymeric substances (EPS) existed ubiquitously in biological systems affect the mobility and availability of heavy metals in the environments. The adsorption-desorption behaviors of Hg(II) and Sb(V) on EPS were investigated. The sorption rates follow Sb(V) > Hg(II), and the desorption rates follow reverse order. Applications of ethylene diamine tetraacetic acid (EDTA), Ca(II) and pH shocks affect desorption rates and desorbed quantities of Hg(II) from EPS-Hg complex. Temperature shock minimally affects the desorption rate of Hg(II). Conversely, the EPS-Sb complex is stable subjected to EDTA, Ca(II), temperature or pH shocks. The excitation-emission matrix (EEM) fluorescence spectroscopy and fast-Fourier (FT-IR) analysis showed that Hg(II) and Sb(V) principally interacted with polysaccharides and protein-like compounds in the EPS, respectively. The EPS-Hg complex presents a time bomb that may release high levels of Hg(II) in short time period under environmental shocks. PMID:23247408

  11. Desorption of Hg(II) and Sb(V) on extracellular polymeric substances: effects of pH, EDTA, Ca(II) and temperature shocks.

    PubMed

    Zhang, Daoyong; Lee, Duu-Jong; Pan, Xiangliang

    2013-01-01

    Extracellular polymeric substances (EPS) existed ubiquitously in biological systems affect the mobility and availability of heavy metals in the environments. The adsorption-desorption behaviors of Hg(II) and Sb(V) on EPS were investigated. The sorption rates follow Sb(V) > Hg(II), and the desorption rates follow reverse order. Applications of ethylene diamine tetraacetic acid (EDTA), Ca(II) and pH shocks affect desorption rates and desorbed quantities of Hg(II) from EPS-Hg complex. Temperature shock minimally affects the desorption rate of Hg(II). Conversely, the EPS-Sb complex is stable subjected to EDTA, Ca(II), temperature or pH shocks. The excitation-emission matrix (EEM) fluorescence spectroscopy and fast-Fourier (FT-IR) analysis showed that Hg(II) and Sb(V) principally interacted with polysaccharides and protein-like compounds in the EPS, respectively. The EPS-Hg complex presents a time bomb that may release high levels of Hg(II) in short time period under environmental shocks.

  12. α-Lactalbumin:Oleic Acid Complex Spontaneously Delivers Oleic Acid to Artificial and Erythrocyte Membranes.

    PubMed

    Wen, Hanzhen; Strømland, Øyvind; Halskau, Øyvind

    2015-09-25

    Human α-lactalbumin made lethal to tumor cells (HAMLET) is a tumoricidal complex consisting of human α-lactalbumin and multiple oleic acids (OAs). OA has been shown to play a key role in the activity of HAMLET and its related complexes, generally known as protein-fatty acid (PFA) complexes. In contrast to what is known about the fate of the protein component of such complexes, information about what happens to OA during their action is still lacking. We monitored the membrane, OA and protein components of bovine α-lactalbumin complexed with OA (BLAOA; a HAMLET-like substance) and how they associate with each other. Using ultracentrifugation, we found that the OA and lipid components follow each other closely. We then firmly identify a transfer of OA from BLAOA to both artificial and erythrocyte membranes, indicating that natural cells respond similarly to BLAOA treatment as artificial membranes. Uncomplexed OA is unable to similarly affect membranes at the conditions tested, even at elevated concentrations. Thus, BLAOA can spontaneously transfer OA to a lipid membrane. After the interaction with the membrane, the protein is likely to have lost most or all of its OA. We suggest a mechanism for passive import of mainly uncomplexed protein into cells, using existing models for OA's effect on membranes. Our results are consistent with a membrane destabilization mediated predominantly by OA insertion being a significant contribution to PFA cytotoxicity.

  13. [Adsorption Properties of Fluorine onto Fulvic Acid-Bentonite Complex].

    PubMed

    Fang, Dun; Tian, Hua-jing; Ye, Xin; He, Ci-li; Dan, You-meng; Wei, Shi-yong

    2016-03-15

    Fulvic Acid-Bentonite (FA-BENT) complex was prepared using coprecipitation method, and basic properties of the complex and sorption properties of fluorine at different environmental conditions were studied. XRD results showed that the d₀₀₁ spacing of FA- BENT complex had no obvious change compared with the raw bentonite, although the diffraction peak intensity of smectite in FA-BENT complex reduced, and indicated that FA mainly existed as a coating on the external surface of bentonite. Some functional groups (such as C==O, −OH, etc. ) of FA were observed in FA-BENT FTIR spectra, thus suggesting ligand exchange-surface complexation between FA and bentonite. Higher initial pH values of the reaction system were in favor of the adsorption of fluorine onto FA-BENT, while the equilibrium capacity decreased with the increase of pH at initial pH ≥ 4.50. The adsorption of fluorine onto FA-BENT was also affected by ionic strength, and the main reason might be the "polarity" effect. The adsorption of fluorine onto FA-BENT followed pseudo-second-order kinetic model and was controlled by chemical process ( R² = 0.999 2). Compared with the Freundlich model, Langmuir model was apparently of a higher goodness of fit (R² > 0.994 9) for absorption of fluorine onto FA-BENT. Thermodynamic parameters indicated that the adsorption process of fluorine was an spontaneously endothermic reaction, and was an entropy-driven process (ΔH 32.57 kJ · mol⁻¹, ΔS 112.31 J · (mol · K)⁻¹, ΔG −0.65- −1.76 kJ · mol⁻¹).

  14. [Adsorption Properties of Fluorine onto Fulvic Acid-Bentonite Complex].

    PubMed

    Fang, Dun; Tian, Hua-jing; Ye, Xin; He, Ci-li; Dan, You-meng; Wei, Shi-yong

    2016-03-15

    Fulvic Acid-Bentonite (FA-BENT) complex was prepared using coprecipitation method, and basic properties of the complex and sorption properties of fluorine at different environmental conditions were studied. XRD results showed that the d₀₀₁ spacing of FA- BENT complex had no obvious change compared with the raw bentonite, although the diffraction peak intensity of smectite in FA-BENT complex reduced, and indicated that FA mainly existed as a coating on the external surface of bentonite. Some functional groups (such as C==O, −OH, etc. ) of FA were observed in FA-BENT FTIR spectra, thus suggesting ligand exchange-surface complexation between FA and bentonite. Higher initial pH values of the reaction system were in favor of the adsorption of fluorine onto FA-BENT, while the equilibrium capacity decreased with the increase of pH at initial pH ≥ 4.50. The adsorption of fluorine onto FA-BENT was also affected by ionic strength, and the main reason might be the "polarity" effect. The adsorption of fluorine onto FA-BENT followed pseudo-second-order kinetic model and was controlled by chemical process ( R² = 0.999 2). Compared with the Freundlich model, Langmuir model was apparently of a higher goodness of fit (R² > 0.994 9) for absorption of fluorine onto FA-BENT. Thermodynamic parameters indicated that the adsorption process of fluorine was an spontaneously endothermic reaction, and was an entropy-driven process (ΔH 32.57 kJ · mol⁻¹, ΔS 112.31 J · (mol · K)⁻¹, ΔG −0.65- −1.76 kJ · mol⁻¹). PMID:27337896

  15. Determination of aminopolycarboxylic acids at ultra-trace levels by means of online coupling ion exchange chromatography and inductively coupled plasma-mass spectrometry with indirect detection via their Pd²⁺-complexes.

    PubMed

    Nette, David; Seubert, Andreas

    2015-07-16

    A new indirect IC-ICP-MS method for the determination of aminopolycarboxylic acids in water samples is described. It is based on the addition of an excess of Pd(II) to water samples. The analytes are forced into very strong and negatively charged palladium complexes, separated by ion exchange chromatography and detected by their palladium content, utilizing an on-line coupled ICP-MS. This method is suitable to determine the concentration of 8 aminopolycarboxylic acids (nitrilotriacetic acid (NTA), (2-carboxyethyl) iminodiacetic acid (β-ADA), methylglycinediacetic acid (MGDA), 2-hydroxyethyl) ethylenediamine triacetic acid (HEDTA), diethylene triamine pentaacetic acid (DTPA), ethylendiamine tetraacetic acid (EDTA), 1,3-diaminopropane tetraacetic acid (1,3-PDTA) and 1,2-diaminopropane tetraacetic acid (1,2-PDTA) at the ng kg(-1) level. The method is faster and easier than the established gas chromatography (GC)-method ISO 16588:2002 and up to two orders of magnitude more sensitive than the ion pair chromatography based method of DIN 38413-8. Analytic performance is superior to ISO 16588:2002 and the comparability is good. PMID:26073818

  16. Extractive and oxidative removal of copper bound to humic acid in soil.

    PubMed

    Hwang, Bo-Ram; Kim, Eun-Jung; Yang, Jung-Seok; Baek, Kitae

    2015-04-01

    Copper (Cu) is often found strongly bound to natural organic matter (NOM) in soil through the formation of strong Cu-NOM complexes. Therefore, in order to successfully remediate Cu-contaminated soils, effective removal of Cu bound to soil organic matter should be considered. In this study, we investigated soil washing methods for Cu removal from a synthetic Cu-contaminated model silica soil coated with humic acid (HA) and from field contaminated soil. Various reagents were studied to extract Cu bound to NOM, which included oxidant (H2O2), base (NaOH), and chelating agents (citric acid and ethylenediaminetetraacetic acid (EDTA)). Among the wash reagents, EDTA extracted Cu most effectively since EDTA formed very strong complexes with Cu, and Cu-HA complexes were transformed into Cu-EDTA complexes. NaOH extracted slightly less Cu compared to EDTA. HA was effectively extracted from the model soil under strongly alkaline conditions with NaOH, which seemed to concurrently release Cu bound to HA. However, chemical oxidation with H2O2 was not effective at destroying Cu-HA complexes. Fourier transform infrared spectroscopy and elemental analysis revealed that chelating agents such as citrate and EDTA were adsorbed onto the model soil via possible complexation between HA and extraction agents. The extraction of Cu from a field contaminated soil sample was effective with chelating agents, while oxidative removal with H2O2 and extractive removal with NaOH separated negligible amounts of Cu from the soil. Based on these results, Cu bound to organic matter in soil could be effectively removed by chelating agents, although remnant agents may remain in the soil. PMID:25388560

  17. Extractive and oxidative removal of copper bound to humic acid in soil.

    PubMed

    Hwang, Bo-Ram; Kim, Eun-Jung; Yang, Jung-Seok; Baek, Kitae

    2015-04-01

    Copper (Cu) is often found strongly bound to natural organic matter (NOM) in soil through the formation of strong Cu-NOM complexes. Therefore, in order to successfully remediate Cu-contaminated soils, effective removal of Cu bound to soil organic matter should be considered. In this study, we investigated soil washing methods for Cu removal from a synthetic Cu-contaminated model silica soil coated with humic acid (HA) and from field contaminated soil. Various reagents were studied to extract Cu bound to NOM, which included oxidant (H2O2), base (NaOH), and chelating agents (citric acid and ethylenediaminetetraacetic acid (EDTA)). Among the wash reagents, EDTA extracted Cu most effectively since EDTA formed very strong complexes with Cu, and Cu-HA complexes were transformed into Cu-EDTA complexes. NaOH extracted slightly less Cu compared to EDTA. HA was effectively extracted from the model soil under strongly alkaline conditions with NaOH, which seemed to concurrently release Cu bound to HA. However, chemical oxidation with H2O2 was not effective at destroying Cu-HA complexes. Fourier transform infrared spectroscopy and elemental analysis revealed that chelating agents such as citrate and EDTA were adsorbed onto the model soil via possible complexation between HA and extraction agents. The extraction of Cu from a field contaminated soil sample was effective with chelating agents, while oxidative removal with H2O2 and extractive removal with NaOH separated negligible amounts of Cu from the soil. Based on these results, Cu bound to organic matter in soil could be effectively removed by chelating agents, although remnant agents may remain in the soil.

  18. Injectable hydrogels derived from phosphorylated alginic acid calcium complexes.

    PubMed

    Kim, Han-Sem; Song, Minsoo; Lee, Eun-Jung; Shin, Ueon Sang

    2015-06-01

    Phosphorylation of sodium alginate salt (NaAlg) was carried out using H3PO4/P2O5/Et3PO4 followed by acid-base reaction with Ca(OAc)2 to give phosphorylated alginic acid calcium complexes (CaPAlg), as a water dispersible alginic acid derivative. The modified alginate derivatives including phosphorylated alginic acid (PAlg) and CaPAlg were characterized by nuclear magnetic resonance spectroscopy for (1)H, and (31)P nuclei, high resolution inductively coupled plasma optical emission spectroscopy, Fourier transform infrared spectroscopy, and thermogravimetric analysis. CaPAlg hydrogels were prepared simply by mixing CaPAlg solution (2w/v%) with NaAlg solution (2w/v%) in various ratios (2:8, 4:6, 6:4, 8:2) of volume. No additional calcium salts such as CaSO4 or CaCl2 were added externally. The gelation was completed within about 3-40min indicating a high potential of hydrogel delivery by injection in vivo. Their mechanical properties were tested to be ≤6.7kPa for compressive strength at break and about 8.4kPa/mm for elastic modulus. SEM analysis of the CaPAlg hydrogels showed highly porous morphology with interconnected pores of width in the range of 100-800μm. Cell culture results showed that the injectable hydrogels exhibited comparable properties to the pure alginate hydrogel in terms of cytotoxicity and 3D encapsulation of cells for a short time period. The developed injectable hydrogels showed suitable physicochemical and mechanical properties for injection in vivo, and could therefore be beneficial for the field of soft tissue engineering. PMID:25842118

  19. Ancestral genetic complexity of arachidonic acid metabolism in Metazoa.

    PubMed

    Yuan, Dongjuan; Zou, Qiuqiong; Yu, Ting; Song, Cuikai; Huang, Shengfeng; Chen, Shangwu; Ren, Zhenghua; Xu, Anlong

    2014-09-01

    Eicosanoids play an important role in inducing complex and crucial physiological processes in animals. Eicosanoid biosynthesis in animals is widely reported; however, eicosanoid production in invertebrate tissue is remarkably different to vertebrates and in certain respects remains elusive. We, for the first time, compared the orthologs involved in arachidonic acid (AA) metabolism in 14 species of invertebrates and 3 species of vertebrates. Based on parsimony, a complex AA-metabolic system may have existed in the common ancestor of the Metazoa, and then expanded and diversified through invertebrate lineages. A primary vertebrate-like AA-metabolic system via cyclooxygenase (COX), lipoxygenase (LOX), and cytochrome P450 (CYP) pathways was further identified in the basal chordate, amphioxus. The expression profiling of AA-metabolic enzymes and lipidomic analysis of eicosanoid production in the tissues of amphioxus supported our supposition. Thus, we proposed that the ancestral complexity of AA-metabolic network diversified with the different lineages of invertebrates, adapting with the diversity of body plans and ecological opportunity, and arriving at the vertebrate-like pattern in the basal chordate, amphioxus.

  20. Ancestral genetic complexity of arachidonic acid metabolism in Metazoa.

    PubMed

    Yuan, Dongjuan; Zou, Qiuqiong; Yu, Ting; Song, Cuikai; Huang, Shengfeng; Chen, Shangwu; Ren, Zhenghua; Xu, Anlong

    2014-09-01

    Eicosanoids play an important role in inducing complex and crucial physiological processes in animals. Eicosanoid biosynthesis in animals is widely reported; however, eicosanoid production in invertebrate tissue is remarkably different to vertebrates and in certain respects remains elusive. We, for the first time, compared the orthologs involved in arachidonic acid (AA) metabolism in 14 species of invertebrates and 3 species of vertebrates. Based on parsimony, a complex AA-metabolic system may have existed in the common ancestor of the Metazoa, and then expanded and diversified through invertebrate lineages. A primary vertebrate-like AA-metabolic system via cyclooxygenase (COX), lipoxygenase (LOX), and cytochrome P450 (CYP) pathways was further identified in the basal chordate, amphioxus. The expression profiling of AA-metabolic enzymes and lipidomic analysis of eicosanoid production in the tissues of amphioxus supported our supposition. Thus, we proposed that the ancestral complexity of AA-metabolic network diversified with the different lineages of invertebrates, adapting with the diversity of body plans and ecological opportunity, and arriving at the vertebrate-like pattern in the basal chordate, amphioxus. PMID:24801744

  1. Enhancing radium solubilization in soils by citrate, EDTA, and EDDS chelating amendments.

    PubMed

    Prieto, C; Lozano, J C; Blanco Rodríguez, P; Tomé, F Vera

    2013-04-15

    The effect of three chelating agents (citrate, EDTA, and EDDS) on the solubilization of radium from a granitic soil was studied systematically, considering different soil pH values, chelating agent concentrations, and leaching times. For all the chelating agents tested, the amount of radium leached proved to be strongly dependent on the pH of the substrate: only for acidic conditions did the amount of radium released increase significantly relative to the controls. Under the best conditions, the radium released from the amended soil was greater by factors of 20 in the case of citrate, 18 for EDTA, and 14 for EDDS. The greatest improvement in the release of radium was obtained for the citrate amendment at the highest concentration tested (50 mmol kg(-1)). A slightly lower amount of radium was leached with EDTA at 5 mmol kg(-1) soil, but the solubilization over time was very different from that observed with citrate or EDDS. With EDTA, a maximum in radium leaching was reached on the first day after amendment, while with citrate, the maximum was attained on the fourth day. With EDDS, radium leaching increased slightly but steadily with time (until the sixth day), but the net effect for the period tested was the lowest of the three reagents.

  2. Further studies of NO sub x control in aqueous scrubbers using ferrouster dot EDTA

    SciTech Connect

    Mendelsohn, M.H.; Livengood, C.D.; Harkness, J.B.L.

    1991-01-01

    Argonne National Laboratory has been conducting research on combined nitrogen oxides (NO{sub x}) and sulfur dioxide (SO{sub 2}) control systems. The research program has recently been focused on studies of aqueous scrubber systems enhanced with chemical additives to promote NO{sub x} removal. Tests have been conducted in a laboratory-scale scrubber system using experimental conditions selected to simulate the scrubbing of flue gas from high-sulfur coal combustion. Last year we reported the first studies performed with ferrous ethylenediaminetetraacetic acid (Fe(2){center dot}EDTA) combined with an antioxidant/reducing agent in a sodium-carbonate chemistry. This year we initiated work with Fe(2){center dot}EDTA in a lime chemistry. We found that the previously studied antioxidant/reducing agents were not as effective in a lime chemistry as they were in a sodium-carbonate chemistry. Therefore, several new antioxidant candidates were identified and screened in our aqueous scrubber system. In this paper, we compare the results obtained last year for Fe(2){center dot}EDTA alone in sodium carbonate with results obtained recently in a lime scrubber chemistry. The improvements in performance possible through the use of antioxidant/reducing agents in combination with the Fe(2){center dot}EDTA will also be discussed and used as the basis for some conclusions regarding the important chemical mechanisms. 5 refs., 6 figs.

  3. Controllable synthesis of ultrathin vanadium oxide nanobelts via an EDTA-mediated hydrothermal process

    NASA Astrophysics Data System (ADS)

    Yu-Xiang, Qin; Cheng, Liu; Wei-Wei, Xie; Meng-Yang, Cui

    2016-02-01

    Ultrathin VO2 nanobelts with rough alignment features are prepared on the induction layer-coated substrates by an ethylenediaminetetraacetic acid (EDTA)-mediated hydrothermal process. EDTA acts as a chelating reagent and capping agent to facilitate the one-dimensional (1D) preferential growth of ultrathin VO2 nanobelts with high crystallinities and good uniformities. The annealed induction layer and concentration of EDTA are found to play crucial roles in the formation of aligned and ultrathin nanobelts. Variation in EDTA concentration can change the VO2 morphology of ultrathin nanobelts into that of thick nanoplates. Mild annealing of ultrathin VO2 nanobelts at 350 °C in air results in the formation of V2O5 nanobelts with a nearly unchanged ultrathin structure. The nucleation and growth mechanism involved in the formations of nanobelts and nanoplates are proposed. The ethanol gas sensing properties of the V2O5 nanobelt networks-based sensor are investigated in a temperature range from 100 °C to 300 °C over ethanol concentrations ranging from 3 ppm to 500 ppm. The results indicate that the V2O5 nanobelt network sensor exhibits high sensitivity, good reversibility, and fast response-recovery characteristics with an optimal working temperature of 250 °C. Project supported by the National Natural Science Foundation of China (Grant Nos. 61274074, 61271070, and 61574100).

  4. Ternary Complexes of Iron, Amyloid-β and Nitrilotriacetic Acid

    PubMed Central

    Jiang, Dianlu; Li, Xiangjun; Williams, Renee; Patel, Sveti; Men, Lijie; Wang, Yinsheng; Zhou, Feimeng

    2009-01-01

    The interaction of amyloid-β (Aβ) and redox-active metals, two important biomarkers present in the senile plaques of AD brain, has been suggested to either enhance the Aβ aggregation or facilitate the generation of reactive oxygen species (ROS). The present study investigates the nature of the interaction between the metal-binding domain of Aβ, viz, Aβ(1-16), and the Fe(III) or Fe(II) complex with nitrilotriacetic acid (NTA). Using electrospray ionization mass spectrometry (ESI-MS), the formation of a ternary complex of Aβ(1-16), Fe(III), and NTA with a stoichiometry of 1:1:1 was identified. MS also revealed that the NTA moiety can be detached via collision-induced dissociation. The cumulative dissociation constants of both Aβ-Fe(III)-NTA and Aβ-Fe(II)-NTA were deduced to be 6.3 × 10-21 M2 and 5.0 × 10-12 M2, respectively, via measuring the fluorescence quenching of the sole tyrosine residue on Aβ upon the complex formation. The redox properties of these two complexes were investigated by cyclic voltammetry. The redox potential of the Aβ-Fe(III)-NTA complex was found to be 0.03 V vs. Ag/AgCl, which is negatively shifted by 0.54 V when compared to the redox potential of free Fe(III)/Fe(II). Despite such a large potential modulation, the redox potential of the Aβ-Fe(III)-NTA complex is still sufficiently high for occurrence of a range of redox reactions with cellular species. Aβ-Fe(II)-NTA electrogenerated from Aβ-Fe(III)-NTA was also found to catalyze the reduction of oxygen to produce H2O2. These findings provide significant insight into the role of iron and Aβ in the development of AD. The binding of iron by Aβ modulates the redox potential to a level where its redox cycling occurs. In the presence of a biological reductant (antioxidant), redox cycling of iron could disrupt the redox balance within the cellular milieu. As a consequence, not only ROS is continuously produced, but also oxygen and biological reductants can be depleted. A cascade of

  5. Effects of humic acid-metal complexes on hepatic carnitine palmitoyltransferase, carnitine acetyltransferase and catalase activities

    SciTech Connect

    Fungjou Lu; Youngshin Chen . Dept. of Biochemistry); Tienshang Huang . Dept. of Medicine)

    1994-03-01

    A significant increase in activities of hepatic carnitine palmitoyltransferase and carnitine acetyltransferase was observed in male Balb/c mice intraperitoneally injected for 40 d with 0.125 mg/0.1 ml/d humic acid-metal complexes. Among these complexes, the humic acid-As complex was relatively effective, whereas humic acid-25 metal complex was more effective, and humic acid-26 metal complex was most effective. However, humic acid or metal mixtures, or metal such as As alone, was not effective. Humic acid-metal complexes also significantly decreased hepatic catalase activity. A marked decrease of 60-kDa polypeptide in liver cytoplasm was also observed on SDS-polyacrylamide gel electrophoresis after the mice had been injected with the complexes. Morphological analysis of a histopathological biopsy of such treated mice revealed several changes in hepatocytes, including focal necrosis and cell infiltration, mild fatty changes, reactive nuclei, and hypertrophy. Humic acid-metal complexes affect activities of metabolic enzymes of fatty acids, and this results in accumulation of hydrogen peroxide and increase of the lipid peroxidation. The products of lipid peroxidation may be responsible for liver damage and possible carcinogenesis. Previous studies in this laboratory had shown that humic acid-metal complex altered the coagulation system and that humic acid, per se, caused vasculopathy. Therefore, humic acid-metal complexes may be main causal factors of not only so-called blackfoot disease, but also the liver cancer prevailing on the southwestern coast of Taiwan.

  6. A microwave study of the ammonia-nitric acid complex

    SciTech Connect

    Ott, M.E.; Leopold, K.R.

    1999-03-11

    Microwave spectra of H{sub 3}{sup 14}N-H{sup 14}NO{sub 3}, H{sub 3}{sup 15}N-H{sup 14}NO{sub 3}, H{sub 3}{sup 14}N-H{sup 15}NO{sub 3}, and H{sub 3}{sup 14}N-D{sup 14}NO{sub 3} have been obtained by Fourier transform spectroscopy in a supersonic jet. The spectra are consistent with a hydrogen-bonded structure having a planar arrangement of the heavy atom frame and a linear or near-linear hydrogen bond involving the HNO{sub 3} proton and the lone pair on the ammonia. The hydrogen bond length obtained from the rotational constants is 1.736(63) {angstrom} and the nitrogen-nitrogen separation is 3.344(12) {angstrom}. The NO single bond of the nitric acid and the C{sub 3} axis of the NH{sub 3} form angles of 54(4){degree} and 21(3){degree}, respectively, with the line joining the centers of mass of the monomers. The hydrogen bond length is significantly shorter than that observed in related complexes such as H{sub 3}N-HCl and H{sub 3}N-HBr, indicating a particularly strong interaction between ammonia and nitric acid.

  7. Role of reducing agent in extraction of arsenic and heavy metals from soils by use of EDTA.

    PubMed

    Kim, Eun Jung; Jeon, Eun-Ki; Baek, Kitae

    2016-06-01

    Although many metal-contaminated sites contain both anionic arsenic and cationic heavy metals, the current remediation technologies are not effective for the simultaneous removal of both anionic and cationic elements from the contaminated sites due to their different characteristics. In this study, the role of reducing agent in simultaneous extraction of As, Cu, Pb, and Zn from contaminated soils was investigated using EDTA. The addition of reducing agents, which includes sodium oxalate (Na2C2O4), ascorbic acid (C6H8O6) and sodium dithionite (Na2S2O4), greatly enhanced the EDTA extraction of both As and heavy metals from the contaminated soils due to the increased mobility of the metals under the reduced conditions. The extent of the enhancement of the EDTA extraction was greatly affected by the reducing conditions. Strong reducing conditions (0.1 M of dithionite) were required for the extraction of metals strongly bound to the soil, while weak reducing conditions (0.01 M of dithionite or 0.1 M of oxalate/ascorbic acid) were sufficient for extraction of metals that were relatively weakly bound to the soil. An almost 90% extraction efficiency of total metals (As, Cu, Zn, and Pb) was obtained from the contaminated soils using the combination of dithionite and EDTA. Our results clearly showed that the combination of dithionite and EDTA can effectively extract As and heavy metals simultaneously from soils under a wide range of pH conditions.

  8. Centrosymmetric dimer of quinuclidine betaine and squaric acid complex

    NASA Astrophysics Data System (ADS)

    Dega-Szafran, Z.; Katrusiak, A.; Szafran, M.

    2012-12-01

    The complex of squaric acid (3,4-dihydroxy-3-cyclobuten-1,2-dion, H2SQ) with quinuclidine betaine (1-carboxymethyl-1-azabicyclo[2.2.2]octane inner salt, QNB), 1, has been characterized by single-crystal X-ray analysis, FTIR and NMR spectroscopies and by DFT calculations. In the crystal of 1, monoclinic space group P21/n, one proton from H2SQ is transferred to QNB. QNBH+ and HSQ- are linked together by a Osbnd H⋯O hydrogen bond of 2.553(2) Å. Two such QNBH+·HSQ- complexes form a centrosymmetric dimer bridged by two Osbnd H⋯O bonds of 2.536(2) Å. The FTIR spectrum is consistent with the X-ray results. The structures of monomer QNBH+·HSQ- (1a) and dimer [QNB·H2SQ]2 (2) have been optimized at the B3LYP/6-311++G(d,p) level of theory. Isolated dimer 2 optimized back to a molecular aggregate of H2SQ and QNB. The calculated frequencies for the optimized structure of dimer 2 have been used to explain the frequencies of the experimental FTIR spectrum. The interpretation of 1H and 13C NMR spectra has been based on the calculated GIAO/B3LYP/6-311++G(d,p) magnetic isotropic shielding constants for monomer 1a.

  9. Polymer complexes. LX. Supramolecular coordination and structures of N(4-(acrylamido)-2-hydroxybenzoic acid) polymer complexes

    NASA Astrophysics Data System (ADS)

    Ghoneim, M. M.; El-Sonbati, A. Z.; El-Bindary, A. A.; Diab, M. A.; Serag, L. S.

    2015-04-01

    A number of novel polymer complexes of various anions of copper(II), cobalt(II), nickel(II) and uranyl(II) with N(4-(acrylamido)-2-hydroxy benzoic acid) (ABH) have been synthesized and characterized by elemental analysis, IR, 1H NMR, magnetic susceptibility measurements, electronic spin resonance, vibrational spectra and thermal analysis. The molecular structures of the ligand are optimized theoretically and the quantum chemical parameters are calculated. Tentative structures for the polymeric metal complexes due to their potential application are also suggested. The IR data exhibit the coordination of ONO2/OAc/SO4 with the metal ions in the polymeric metal complex. Vibrational spectra indicate coordination of carboxylate oxygen and phenolic OH of the ligand giving a MO4 square planar chromophore. Ligand field ESR spectra support square planar geometry around Cu(II). The thermal decomposition of the polymer complexes were discussed in relation to structure, and the thermodynamic parameters of the decomposition stages were evaluated applying Coast-Redfern and Horowitz-Metzger methods.

  10. Analysis of phytochelatin complexes in the lead tolerant vetiver grass [Vetiveria zizanioides (L.)] using liquid chromatography and mass spectrometry.

    PubMed

    Andra, Syam S; Datta, Rupali; Sarkar, Dibyendu; Saminathan, Sumathi K M; Mullens, Conor P; Bach, Stephan B H

    2009-07-01

    Ethylenediamene tetraacetic acid (EDTA) has been used to mobilize soil lead (Pb) and enhance plant uptake for phytoremediation. Chelant bound Pb is considered less toxic compared to free Pb ions and hence might induce less stress on plants. Characterization of possible Pb complexes with phytochelatins (PCn, metal-binding peptides) and EDTA in plant tissues will enhance our understanding of Pb tolerance mechanisms. In a previous study, we showed that vetiver grass (Vetiveria zizanioides L.) can accumulate up to 19,800 and 3350 mg Pb kg(-1) dry weight in root and shoot tissues, respectively; in a hydroponics set-up. Following the basic incubation study, a greenhouse experiment was conducted to elucidate the efficiency of vetiver grass (with or without EDTA) in remediating Pb-contaminated soils from actual residential sites where Pb-based paints were used. The levels of total thiols, PCn, and catalase (an antioxidant enzyme) were measured in vetiver root and shoot following chelant-assisted phytostabilization. In the presence of 15 mM kg (-1) EDTA, vetiver accumulated 4460 and 480 mg Pb kg(-1) dry root and shoot tissue, respectively; that are 15- and 24-fold higher compared to those in untreated controls. Despite higher Pb concentrations in the plant tissues, the amount of total thiols and catalase activity in EDTA treated vetiver tissues was comparable to chelant unamended controls, indicating lowered Pb toxicity by chelation with EDTA. The identification of glutathione (referred as PC1) (m/z 308.2), along with chelated complexes like Pb-EDTA (m/z 498.8) and PC(1)-Pb-EDTA (m/z 805.3) in vetiver root tissue using electrospray tandem mass spectrometry (ES-MS) highlights the possible role of such species towards Pb tolerance in vetiver grass.

  11. Quantitative Analysis of Sulfate in Water by Indirect EDTA Titration

    ERIC Educational Resources Information Center

    Belle-Oudry, Deirdre

    2008-01-01

    The determination of sulfate concentration in water by indirect EDTA titration is an instructive experiment that is easily implemented in an analytical chemistry laboratory course. A water sample is treated with excess barium chloride to precipitate sulfate ions as BaSO[subscript 4](s). The unprecipitated barium ions are then titrated with EDTA.…

  12. The uptake and distribution of cadmium in tomato plants as affected by ethylenediaminetetraacetic acid and 2,4-dinitrophenol.

    PubMed

    Wolterbeek, H T; van der Meer, A; de Bruin, M

    1988-01-01

    The uptake and distribution of cadmium in tomato plants (Lycopersicon esculentum, Mill, cv. Tiny Tim) were examined with and without the presence of ethylenediaminetetraacetic acid (EDTA) as chelating agent and 2,4-dinitrophenol (DNP) as metabolic inhibitor. Eight-week-old intact and derooted tomato seedlings were used in hydroculture experiments with cadmium applied as (115)Cd(NO(3))(2) in a range of concentrations. Measurements of the (115)Cd content of roots, stems and leaves were carried out by gamma-ray spectroscopy. The data showed that applications of both EDTA and DNP resulted in reduced total Cd accumulation in the plants, but relatively enhanced Cd transport into the above-ground plant parts. The Cd mobility in the transport channels in the shoots was increased by EDTA in both intact and derooted plants. Application of DNP leads to increased relative Cd import to leaves in derooted plants, but a reduced import into leaves of intact plants. These results suggest that Cd-complexes are formed in root cells before root-to-shoot transport. Furthermore, initial Cd uptake may be associated with adsorption on the negative charges of the cell walls of the root system. The high Cd mobility in shoots, in experiments with intact plants and Cd-EDTA application, indicates the possibility of simultaneous uptake of Cd and EDTA, possibly as a Cd-EDTA complex. PMID:15092498

  13. Fluorescent complexes of nucleic acids/8-hydroxyquinoline/lanthanum(III) and the fluorometry of nucleic acids

    SciTech Connect

    Cheng Zhi Huang; Ke An Li; Shen Yang Tong

    1996-07-01

    The ternary fluorescent complexes of nucleic acids/8-hydroxyquinoline/lanthanum (III) were studied. Nucleic acids in the study involve natured and thermally denatured calf thymus DNA, fish sperm DNA and yeast RNA. In the range of PH 8.0-8.4 (controlled by NH{sub 3}-NH{sub 4}Cl buffer) ternary fluorescent complexes are formed which emit at 485.0 nm for calf thymus DNA and at 480.0 nm for fish sperm DNA when excited at 265.0 nm. Based on the fluorescence reactions sensitive fluorometric methods for nucleic acids were proposed. Using optimal conditions, the calibration curves were linear in the range of 0.4 --3.6 {mu}g{sup .}ml{sup -1} for calf thymus DNA, 0.4 -- 4.0 {mu}g{sup .}ml{sup -1} for fish sperm DNA and 0.4 --4.0{mu}g{sup .}ml{sup -1} for yeast RNA, respectively. Five synthetic samples were determined with satisfaction.

  14. 40 CFR 721.10089 - Modified salicylic acid, zirconium complex (generic).

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 32 2012-07-01 2012-07-01 false Modified salicylic acid, zirconium... Specific Chemical Substances § 721.10089 Modified salicylic acid, zirconium complex (generic). (a) Chemical... as modified salicylic acid, zirconium complex (PMN P-00-552) is subject to reporting under...

  15. 40 CFR 721.10089 - Modified salicylic acid, zirconium complex (generic).

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 31 2011-07-01 2011-07-01 false Modified salicylic acid, zirconium... Specific Chemical Substances § 721.10089 Modified salicylic acid, zirconium complex (generic). (a) Chemical... as modified salicylic acid, zirconium complex (PMN P-00-552) is subject to reporting under...

  16. 40 CFR 721.10089 - Modified salicylic acid, zirconium complex (generic).

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 31 2014-07-01 2014-07-01 false Modified salicylic acid, zirconium... Specific Chemical Substances § 721.10089 Modified salicylic acid, zirconium complex (generic). (a) Chemical... as modified salicylic acid, zirconium complex (PMN P-00-552) is subject to reporting under...

  17. 40 CFR 721.10089 - Modified salicylic acid, zirconium complex (generic).

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 32 2013-07-01 2013-07-01 false Modified salicylic acid, zirconium... Specific Chemical Substances § 721.10089 Modified salicylic acid, zirconium complex (generic). (a) Chemical... as modified salicylic acid, zirconium complex (PMN P-00-552) is subject to reporting under...

  18. 40 CFR 721.10089 - Modified salicylic acid, zirconium complex (generic).

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 30 2010-07-01 2010-07-01 false Modified salicylic acid, zirconium... Specific Chemical Substances § 721.10089 Modified salicylic acid, zirconium complex (generic). (a) Chemical... as modified salicylic acid, zirconium complex (PMN P-00-552) is subject to reporting under...

  19. EDTA-dependent pseudothrombocytopenia: further insights and recommendations for prevention of a clinically threatening artifact.

    PubMed

    Lippi, Giuseppe; Plebani, Mario

    2012-08-01

    Ethylenediaminetetra-acetic acid (EDTA) is widely used as anticoagulant in laboratory medicine. EDTA-dependent pseudothrombocytopenia is a rare phenomenon (i.e., around 0.1% in the general population), which is mostly due to the presence of EDTA-dependent antiplatelet antibodies that react optimally between 0°C and 4°C, recognize the cytoadhesive receptors gpIIb-IIIa, stimulate the expression of activation antigens, trigger activation of tyrosine kinase, platelet agglutination and clumping in vitro, which finally lead to a spuriously decreased platelet count. The reliable and timely identification of this artifact is essential, since there a high chance that it may be confused with other life-threatening platelet disorders, or otherwise lead to inappropriate clinical and therapeutic decision-making. Five basic criteria should be fulfilled to raise the clinical suspicion of EDTA-dependent pseudothrombocytopenia, i.e., (i) abnormal platelet count, typically <100×10(9)/L; (ii) occurrence of thrombocytopenia in EDTA-anticoagulated samples at room temperature, but to a much lesser extent in samples collected with other anticoagulants and/or kept warmed at ~37°C; (iii) time-dependent fall of platelet count in the EDTA specimen; (iv) evidence of platelet aggregates and clumps in EDTA-anticoagulated samples with either automated cell counting or microscopic analysis; (v) lack of signs or symptoms of platelet disorders. Several remedies have been proposed, such as warming the sample to 37°C or using additives or specific formulations of anticoagulants including buffered sodium citrate, heparin, ammonium oxalate, β-hydroxyethyltheophylline, sodium fluoride, CPT (trisodium citrate, pyridoxal 5'-phosphate and Tris), antiplatelet agents, potassium azide, amikacin, kanamycin or other aminoglycosides, and calcium replacement with the simultaneous addition of calcium chloride/heparin. According to available evidences, the most suitable and practical approach so far for most

  20. Molecular complexes of alprazolam with carboxylic acids, boric acid, boronic acids, and phenols. Evaluation of supramolecular heterosynthons mediated by a triazole ring.

    PubMed

    Varughese, Sunil; Azim, Yasser; Desiraju, Gautam R

    2010-09-01

    A series of molecular complexes, both co-crystals and salts, of a triazole drug-alprazolam-with carboxylic acids, boric acid, boronic acids, and phenols have been analyzed with respect to heterosynthons present in the crystal structures. In all cases, the triazole ring behaves as an efficient hydrogen bond acceptor with the acidic coformers. The hydrogen bond patterns exhibited with aromatic carboxylic acids were found to depend on the nature and position of the substituents. Being a strong acid, 2,6-dihydroxybenzoic acid forms a salt with alprazolam. With aliphatic dicarboxylic acids alprazolam forms hydrates and the water molecules play a central role in synthon formation and crystal packing. The triazole ring makes two distinct heterosynthons in the molecular complex with boric acid. Boronic acids and phenols form consistent hydrogen bond patterns, and these are seemingly independent of the substitutional effects. Boronic acids form noncentrosymmetric cyclic synthons, while phenols form O--H...N hydrogen bonds with the triazole ring.

  1. Morphological characteristics, oxidative stability and enzymic hydrolysis of amylose-fatty acid complexes.

    PubMed

    Marinopoulou, Anna; Papastergiadis, Efthimios; Raphaelides, Stylianos N; Kontominas, Michael G

    2016-05-01

    Complexes of amylose with fatty acids varying in carbon chain length and degree of unsaturation were prepared at 30, 50 or 70°C by dissolving amylose in 0.1N KOH and mixing with fatty acid potassium soap solution. The complexes were obtained in solid form as precipitates after neutralization. SEM microscopy revealed that the morphology of the complexes was that of ordered lamellae separated from amorphous regions whereas confocal laser scanning microscopy showed images of the topography of the guest molecules in the complex matrix. FTIR spectroscopy revealed that the absorption peak attributed to carbonyl group of free fatty acid was shifted when the fatty acid was in the form of amylose complex. Thermo-gravimetry showed that the unsaturated fatty acids were effectively protected from oxidation when they were complexed with amylose whereas enzymic hydrolysis experiments showed that the guest molecules were quantitatively released from the amylose complexes. PMID:26877002

  2. Morphological characteristics, oxidative stability and enzymic hydrolysis of amylose-fatty acid complexes.

    PubMed

    Marinopoulou, Anna; Papastergiadis, Efthimios; Raphaelides, Stylianos N; Kontominas, Michael G

    2016-05-01

    Complexes of amylose with fatty acids varying in carbon chain length and degree of unsaturation were prepared at 30, 50 or 70°C by dissolving amylose in 0.1N KOH and mixing with fatty acid potassium soap solution. The complexes were obtained in solid form as precipitates after neutralization. SEM microscopy revealed that the morphology of the complexes was that of ordered lamellae separated from amorphous regions whereas confocal laser scanning microscopy showed images of the topography of the guest molecules in the complex matrix. FTIR spectroscopy revealed that the absorption peak attributed to carbonyl group of free fatty acid was shifted when the fatty acid was in the form of amylose complex. Thermo-gravimetry showed that the unsaturated fatty acids were effectively protected from oxidation when they were complexed with amylose whereas enzymic hydrolysis experiments showed that the guest molecules were quantitatively released from the amylose complexes.

  3. Ligand-enhanced electrokinetic remediation of metal-contaminated marine sediments with high acid buffering capacity.

    PubMed

    Masi, Matteo; Iannelli, Renato; Losito, Gabriella

    2016-06-01

    The suitability of electrokinetic remediation for removing heavy metals from dredged marine sediments with high acid buffering capacity was investigated. Laboratory-scale electrokinetic remediation experiments were carried out by applying two different voltage gradients to the sediment (0.5 and 0.8 V/cm) while circulating water or two different chelating agents at the electrode compartments. Tap water, 0.1 M citric acid and 0.1 M ethylenediaminetetraacetic acid (EDTA) solutions were used respectively. The investigated metals were Zn, Pb, V, Ni and Cu. In the unenhanced experiment, the acid front could not propagate due to the high acid buffering capacity of the sediments; the production of OH(-) ions at the cathode resulted in a high-pH environment causing the precipitation of CaCO3 and metal hydroxides. The use of citric acid prevented the formation of precipitates, but solubilisation and mobilisation of metal species were not sufficiently achieved. Metal removal was relevant when EDTA was used as the conditioning agent, and the electric potential was raised up to 0.8 V/cm. EDTA led to the formation of negatively charged complexes with metals which migrated towards the anode compartment by electromigration. This result shows that metal removal from sediments with high acid buffering capacity may be achieved by enhancing the electrokinetic process by EDTA addition when the acidification of the medium is not economically and/or environmentally sustainable. PMID:26490900

  4. Complexation of NpO2+ with N-methyl-iminodiacetic Acid: in Comparison with Iminodiacetic and Dipicolinic Acids

    SciTech Connect

    Tian, Guoxin; Rao, Linfeng

    2010-10-01

    Complexation of Np(V) with N-methyl-iminodiacetic acid (MIDA) in 1 M NaClO{sub 4} solution was studied with multiple techniques including potentiometry, spectrophotometry, and microcalorimetry. The 1:2 complex, NpO{sub 2}(MIDA){sub 2}{sup 3-} was identified for the first time in aqueous solution. The correlation between its optical absorption properties and symmetry was discussed, in comparison with Np(V) complexes with two structurally related nitrilo-dicarboxylic acids, iminodiacetic acid (IDA) and dipicolinic acid (DPA). The order of the binding strength (DPA > MIDA > IDA) is explained by the difference in the structural and electronic properties of the ligands. In general, the nitrilo-dicarboxylates form stronger complexes with Np(V) than oxy-dicarboxylates due to a much more favorable enthalpy of complexation.

  5. Photocatalytic degradation of indigo carmine by hydrothermally synthesized Bi₂MoO ₆ in presence of EDTA.

    PubMed

    Sánchez Trinidad, C; Martínez-de la Cruz, A; López Cuéllar, E

    2015-01-01

    Bi2MoO6 oxide was synthesized by hydrothermal reaction in the presence of EDTA under different experimental conditions (time of reaction and EDTA concentration) in order to obtain materials with specific textural properties. It was determined that the addition of EDTA influences the final physical properties of Bi2MoO6. The photocatalytic activity of Bi2MoO6 samples was evaluated in the degradation reaction of indigo carmine (IC) in aqueous solution under solar radiation type. The best results as photocatalyst were obtained with the sample hydrothermally synthesized at 150 ºC for 4h in presence of a 0.031 M EDTA solution. This sample was able to whiten a solution of IC in a 94% after 120 min of lamp irradiation with t 1/2 = 31 min. In general, the samples prepared with lower concentrations of EDTA were the best photocatalysts. A gradual decrease in the activity was observed in the samples prepared with the same EDTA concentration as was increased in the reaction time. Beyond differences in morphology and textural properties of the samples prepared, the presence of EDTA by-products on the samples and the decomposition degree of it were important factors in determining the activity of the photocatalysts. Analysis of total organic carbon (TOC) of samples irradiated for 100 h confirmed that Bi2MoO6 oxide is able to mineralize the complex organic molecule of IC to CO2 and H2O in 55 %.

  6. Amine-based extraction recovery of Cu(II) from aqueous solutions in the presence of EDTA. Equilibrium studies

    SciTech Connect

    Juang, R.S.; Chen, Y.J.; Huang, I.P.

    1999-11-01

    The distribution ratios of Cu(II) between kerosene solutions of Aliquat 336 and water containing EDTA (ethylenediaminetetraacetic acid) are measured. Experiments were performed as a function of the pH, the concentration of Cu(II), the concentration ratio of EDTA to Cu(II), and the concentration of amine. It is shown that the distribution ratios first increase with pH and then decrease with further increase in pH up to 7.0. The effect of temperature on the extraction was studied, and the enthalpy of the extraction reaction was determined. Finally, the nonideal behavior of the organic phase is discussed.

  7. Optimizing the molarity of a EDTA washing solution for saturated-soil remediation of trace metal contaminated soils.

    PubMed

    Andrade, M D; Prasher, S O; Hendershot, W H

    2007-06-01

    Three experiments were conducted to optimize the use of ethylenediaminetetraacetic acid (EDTA) for reclaiming urban soils contaminated with trace metals. As compared to Na(2)EDTA, (NH(4))(2)EDTA extracted 60% more Zn and equivalent amounts of Cd, Cu and Pb from a sandy loam. When successively saturating and draining loamy sand columns during a washing cycle, which submerged it once with a (NH(4))(2)EDTA wash and four times with deionised water, the post-wash rinses largely contributed to the total cumulative extraction of Cd, Co, Cr, Cu, Mn, Ni, Pb and Zn. Both the washing solution and the deionised water rinses were added in a 2:5 liquid to soil (L:S) weight ratio. For equal amounts of EDTA, concentrating the washing solution and applying it and the ensuing rinses in a smaller 1:5 L:S weight ratio, instead of a 2:5 L:S weight ratio, increased the extraction of targeted Cr, Cu, Ni, Pb and Zn.

  8. An evaluation of EDTA additions for improving the phytoremediation efficiency of different plants under various cultivation systems.

    PubMed

    Luo, Jie; Qi, Shihua; Gu, X W Sophie; Wang, Jinji; Xie, Xianming

    2016-05-01

    Previous studies have shown that phytoremediation usually requires soil amendments, such as chelates, to mobilize low bioavailability heavy metals for better plant absorption and, consequently, for remediation efficiency. A total dry biomass of 3.39 and 0.0138 kg per plant was produced by a phytoremediator, Eucalyptus globulus, and a nitrogen fixing crop, Cicer arietinum (chickpea), respectively. The accumulation of Pb in E. globulus and chickpea reached 1170.61 and 1.33 mg per plant (700 and 324 mg kg(-1)), respectively, under an ethylene diamine tetraacetic acid (EDTA) treatment, which was a five and sixfold increase over the value in untreated experiments, respectively. EDTA enhanced the phytoremediation efficiency and increased the heavy metal concentration in the soil solution. In pot experiments, approximately 27 % of the initial Pb leached from the spiked soil after EDTA and 25 mm artificial precipitation additions into soil without plants, which was considerably larger than the value under the same conditions without EDTA application (7 %). E. globulus planted in a mixed culture had higher water use efficiency than monocultures of either species in field experiments, and E. globulus intercepted almost all of the artificial precipitation in the pot experiments. This study demonstrates that E. globulus can maximize the potential of EDTA for improving the phytoremediation efficiency and minimizing its negative effects to the environment simultaneously by absorbing the metal-rich leachate, especially in a mixed culture of E. globulus and chickpeas. PMID:26846211

  9. Effect of EDTA Conditioning and Carbodiimide Pretreatment on the Bonding Performance of All-in-One Self-Etch Adhesives

    PubMed Central

    Singh, Shipra; Nagpal, Rajni; Tyagi, Shashi Prabha; Manuja, Naveen

    2015-01-01

    Objective. This study evaluated the effect of ethylenediaminetetraacetic acid (EDTA) conditioning and carbodiimide (EDC) pretreatment on the shear bond strength of two all-in-one self-etch adhesives to dentin. Methods. Flat coronal dentin surfaces were prepared on one hundred and sixty extracted human molars. Teeth were randomly divided into eight groups according to two different self-etch adhesives used [G-Bond and OptiBond-All-In-One] and four different surface pretreatments: (a) adhesive applied following manufacturer's instructions; (b) dentin conditioning with 24% EDTA gel prior to application of adhesive; (c) EDC pretreatment followed by application of adhesive; (d) application of EDC on EDTA conditioned dentin surface followed by application of adhesive. Composite restorations were placed in all the samples. Ten samples from each group were subjected to immediate and delayed (6-month storage in artificial saliva) shear bond strength evaluation. Data collected was subjected to statistical analysis using three-way ANOVA and post hoc Tukey's test at a significance level of p < 0.05.  Results and Conclusion. EDTA preconditioning as well as EDC pretreatment alone had no significant effect on the immediate and delayed bond strengths of either of the adhesives. However, EDC pretreatment on EDTA conditioned dentin surface resulted in preservation of resin-dentin bond strength of both adhesives with no significant fall over six months. PMID:26557850

  10. Thermodynamics of the complexation of arabinogalactan with salicylic and p-aminobenzoic acids in aqueous solutions

    NASA Astrophysics Data System (ADS)

    Mudarisova, R. Kh.; Badykova, L. A.

    2016-03-01

    The thermodynamics of complexation of arabinogalactan with salicylic and p-aminobenzoic acids in aqueous solutions is studied by means spectroscopy. The standard thermodynamic characteristics (Δ H°; Δ G°; Δ S°) of complexation are calculated.

  11. Effect of enzyme secreting bacterial pretreatment on enhancement of aerobic digestion potential of waste activated sludge interceded through EDTA.

    PubMed

    Kavitha, S; Adish Kumar, S; Yogalakshmi, K N; Kaliappan, S; Rajesh Banu, J

    2013-12-01

    In this study, the effect of Ethylene diamine tetra acetic acid (EDTA) on Extracellular polymeric substance (EPS) removal tailed with bacterial enzymatic pretreatment on aerobic digestion of activated sludge was studied. In order to enhance the accessibility of sludge to the enzyme secreting bacteria; the extracellular polymeric substances were removed using EDTA. EDTA efficiently removed the EPS with limited cell lysis and enhanced the sludge enzyme activity at its lower concentration of 0.2 g/g SS. The sludge was then subjected to bacterial pretreatment to enhance the aerobic digestion. In aerobic digestion the best results in terms of Suspended solids (SS) reduction (48.5%) and COD (Chemical oxygen demand) solubilization (47.3%) was obtained in experimental reactor than in control. These results imply that aerobic digestion can be enhanced efficiently through bacterial pretreatment of EPS removed sludge.

  12. Lipid complex effect on fatty acid profile and chemical composition of cow milk and cheese.

    PubMed

    Bodkowski, R; Czyż, K; Kupczyński, R; Patkowska-Sokoła, B; Nowakowski, P; Wiliczkiewicz, A

    2016-01-01

    The effect of administration of lipid complex (LC) on cow milk and cheese characteristics was studied. Lipid complex was elaborated based on grapeseed oil with synthesized conjugated linoleic acid (CLA) and Atlantic mackerel oil enriched in n-3 fatty acids. The 4-wk experiment was conducted on 30 Polish Holstein Friesian cows. The experimental group cow diet was supplemented with 400 g/d of LC (containing 38% CLA, and eicosapentaenoic acid + docosahexaenoic acid in a relative amount of 36.5%) on a humic-mineral carrier. The chemical composition and fatty acid profile of milk and rennet cheese from raw fresh milk were analyzed. Lipid complex supplementation of the total mixed ration had no effect on milk yield and milk composition, except fat content, which decreased from 4.6 to 4.1%, a 10.9% decrease. Milk from cows treated with LC had greater relative amounts of unsaturated fatty acids, particularly polyunsaturated fatty acids, and lesser relative amounts of saturated fatty acids. Lipid complex addition changed milk fat fatty acid profile: C18:2 cis-9,trans-11 and trans-10,cis-12 isomer (CLA) contents increased by 278 and 233%, respectively, as did eicosapentaenoic acid (C20:5) and docosahexaenoic acid (C22:6) contents. Milk fat fatty acid profile changes were correlated with the modifications in rennet cheese fatty acid profile. Lipid complex supplementation of dairy cows produced considerable changes in the biological value of milk and cheese fat.

  13. Lipid complex effect on fatty acid profile and chemical composition of cow milk and cheese.

    PubMed

    Bodkowski, R; Czyż, K; Kupczyński, R; Patkowska-Sokoła, B; Nowakowski, P; Wiliczkiewicz, A

    2016-01-01

    The effect of administration of lipid complex (LC) on cow milk and cheese characteristics was studied. Lipid complex was elaborated based on grapeseed oil with synthesized conjugated linoleic acid (CLA) and Atlantic mackerel oil enriched in n-3 fatty acids. The 4-wk experiment was conducted on 30 Polish Holstein Friesian cows. The experimental group cow diet was supplemented with 400 g/d of LC (containing 38% CLA, and eicosapentaenoic acid + docosahexaenoic acid in a relative amount of 36.5%) on a humic-mineral carrier. The chemical composition and fatty acid profile of milk and rennet cheese from raw fresh milk were analyzed. Lipid complex supplementation of the total mixed ration had no effect on milk yield and milk composition, except fat content, which decreased from 4.6 to 4.1%, a 10.9% decrease. Milk from cows treated with LC had greater relative amounts of unsaturated fatty acids, particularly polyunsaturated fatty acids, and lesser relative amounts of saturated fatty acids. Lipid complex addition changed milk fat fatty acid profile: C18:2 cis-9,trans-11 and trans-10,cis-12 isomer (CLA) contents increased by 278 and 233%, respectively, as did eicosapentaenoic acid (C20:5) and docosahexaenoic acid (C22:6) contents. Milk fat fatty acid profile changes were correlated with the modifications in rennet cheese fatty acid profile. Lipid complex supplementation of dairy cows produced considerable changes in the biological value of milk and cheese fat. PMID:26506539

  14. Laser Monitoring Of Phytoextraction Enhancement Of Lead Contaminated Soil Adopting EDTA And EDDS

    NASA Astrophysics Data System (ADS)

    Hassan, M.; Abdelhamied, M.; Hanafy, A. H.; Fantoni, R.; Harith, M. A.

    2011-09-01

    Removal of heavy metals (HMs) such as Pb from soil, wastewater, and air is essential for environment and human health. Phytoremediation is a well established technology based on the use of certain green plants for contaminants removal from soil, wastewater as well as air. Scented geranium, Pelargonium zonal, is a flowering plant recently used in HMs removal from contaminated soil. In the present work, EDTA (ethylenediaminetetraacetic acid) and EDDS (S, S-ethylenediaminedisuccinic acid) were used as chemical assistants providing higher Pb availability for extraction by plant roots. Lead was artificially added to the planting media, peatmoss, at different concentrations. Laser induced breakdown spectroscopy (LIBS) was used to follow up Pb relative concentrations in peatmoss as well as plant shoots, at different sampling times during the experiment period. Laser induced chlorophyll fluorescence (LICF), has been also used to evaluate chlorophyll formation and photosynthetic apparatus status in geranium plants. Such measurements were performed on geranium plants grown under various Pb levels, as well as EDTA and EDDS combinations. The combined effect of EDTA and EDDS was found to enhance Pb extraction with time. Good correlation was found between LICF results and chlorophyll (a) (Chl.a) concentrations in plant tissues extracted by chemical analysis.

  15. EDTA and HEDTA effects on Cd, Cr, and Ni uptake by Helianthus annuus.

    PubMed

    Chen, H; Cutright, T

    2001-10-01

    Phytoremediation has shown great potential as an alternative treatment for the remediation of heavy-metal-contaminated soils and groundwater. However, the lack of a clear understanding pertaining to metal uptake/translocation mechanisms, enhancement amendments, and external effects on phytoremediation has hindered its full-scale application. The objective of this research was to investigate the ability of synthetic chelators for enhancing the phytoremediation of cadmium-, chromium- and nickel-contaminated soil. Ethylenediaminetriacetic acid (EDTA) and N-(2-hydroxyethyl)-ethylenediaminetriacetic acid (HEDTA) were applied to the soil at various dosages to elevate metal mobility. Uptake into and translocation within Helianthus annuus was determined. It was found that EDTA at a rate of 0.5 g/kg significantly increased the shoot concentrations of Cd and Ni from 34 and 15 to 115 and 117 mg/kg, respectively. The total removal efficiency for EDTA was 59 microg/plant. HEDTA at the same application rate resulted in a total metal uptake of 42 microg/plant. These research demonstrated that chelator enhancement is plant- and metal-specific and is subjective to inhibition when multiple heavy metals are present. Results also showed that chelator toxicity reduced the plant's biomass, thereby decreasing the amount of metal accumulation.

  16. Effects of chemical and enzymatic modifications on starch-linoleic acid complex formation.

    PubMed

    Arijaje, Emily Oluwaseun; Wang, Ya-Jane

    2017-02-15

    This study investigated the complexation yield and physicochemical properties of soluble and insoluble starch complexes with linoleic acid when a β-amylase treatment was applied to acetylated and debranched potato starch. The degree of acetylation was generally higher in the soluble complexes than in the insoluble ones. The insoluble complexes from the acetylated starch displayed the V-type pattern, whereas, the soluble complexes displayed a mixture of either the A-/V-type or the B-/V-type pattern. Acetylation decreased onset and peak melting temperatures for the insoluble complexes, whereas no melting endotherm was observed in the soluble complexes. Acetylation substantially increased the amount of complexed linoleic acid in the insoluble complexes, but had little positive effect on the formation of the soluble complexes. The β-amylase treatment significantly increased the complexed linoleic content in both soluble and insoluble complexes for the low acetylated starch, but not for the high acetylated starch. PMID:27664602

  17. Synthesis of 1-(p-isothiocyanatobenzyl) derivatives of DTPA and EDTA. Antibody labeling and tumor-imaging studies

    SciTech Connect

    Brechbiel, M.W.; Gansow, O.A.; Atcher, R.W.; Schlom, J.; Esteban, J.; Simpson, D.E.; Colcher, D.

    1986-07-30

    To investigate the /sup 111/In labeling of tumor-localizing monoclonal antibodies (MoAb), the chelate 1-(p-isothiocyanatobenzyl)diethylenetriaminepentaacetic acid (p-SCN-Bz-DPTA) (1) and its EDTA analogue (2) have been synthesized. By the use of a MoAb (B72.3) specific for a high molecular weight antigen (TAG-72) on cells of a colorectal carcinoma grown in nude mice, optimal chemical conditions for MoAb conjugation of those ligands and of the dicyclic and isobutylcarboxy carbonic anhydrides of DTPA and subsequent /sup 111/In labeling were determined. All conjugates were shown by a competitive binding assay to retain their specificity and activity in vitro when less than one ligand is protein coupled both prior to and after /sup 111/In labeling. Chemical methods for purification of the MoAb were systematically investigated by injection of purified immunoprotein into athymic mice bearing LS-174T tumors that express the TAG-72 antigen. Tissue distribution studies revealed that simple addition of EDTA to labeled immunoglobulins was ineffective at complexing indium not linked to protein by chelates. Similarly, gel chromatography (Sephadex G-50) was not sufficient; rather, size exclusion HPLC had to be employed to remove unreacted /sup 111/In and aggregated antibody. To compare the relative utility of the four chelates for /sup 111/In diagnostic radioimmunoimaging, scintigraphic images of tumor-bearing mice were obtained and evaluated along with tissue distributions. Results showed that clear images of these solid tissue tumors free of extraneous radiation could be obtained only by using p-SCN-Bz-DTPA purified by HPLC. Methods developed are now being employed in clinical trials for diagnosis of human colorectal cancer. 71 references, 5 figures, 1 table.

  18. Amylose inclusion complexation of ferulic acid via lipophilization

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Ferulic acid is an interesting phytochemical that exhibits antioxidant, anti-inflammatory, antimicrobial, UV-absorber, and anticarcinogenic activities. These properties make it of interest in food formulations, cosmetics, polymer, and pharmaceutical applications. However, delivery of ferulic acid in...

  19. Poly(anhydride-esters) Comprised Exclusively of Naturally Occurring Antimicrobials and EDTA: Antioxidant and Antibacterial Activities

    PubMed Central

    2015-01-01

    Carvacrol, thymol, and eugenol are naturally occurring phenolic compounds known to possess antimicrobial activity against a range of bacteria, as well as antioxidant activity. Biodegradable poly(anhydride-esters) composed of an ethylenediaminetetraacetic acid (EDTA) backbone and antimicrobial pendant groups (i.e., carvacrol, thymol, or eugenol) were synthesized via solution polymerization. The resulting polymers were characterized to confirm their chemical composition and understand their thermal properties and molecular weight. In vitro release studies demonstrated that polymer hydrolytic degradation was complete after 16 days, resulting in the release of free antimicrobials and EDTA. Antioxidant and antibacterial assays determined that polymer release media exhibited bioactivity similar to that of free compound, demonstrating that polymer incorporation and subsequent release had no effect on activity. These polymers completely degrade into components that are biologically relevant and have the capability to promote preservation of consumer products in the food and personal care industries via antimicrobial and antioxidant pathways. PMID:24702678

  20. The behavior and importance of lactic acid complexation in Talspeak extraction systems

    SciTech Connect

    Grimes, Travis S.; Nilsson, Mikael; Nash, Kenneth L.

    2008-07-01

    Advanced partitioning of spent nuclear fuel in the UREX +la process relies on the TALSPEAK process for separation of fission-product lanthanides from trivalent actinides. The classic TALSPEAK utilizes an aqueous medium of both lactic acid and diethylenetriaminepentaacetic acid and the extraction reagent di(2-ethylhexyl)phosphoric acid in an aromatic diluent. In this study, the specific role of lactic acid and the complexes involved in the extraction of the trivalent actinides and lanthanides have been investigated using {sup 14}C-labeled lactic acid. Our results show that lactic acid partitions between the phases in a complex fashion. (authors)

  1. EDTA-Cross-Linked β-Cyclodextrin: An Environmentally Friendly Bifunctional Adsorbent for Simultaneous Adsorption of Metals and Cationic Dyes.

    PubMed

    Zhao, Feiping; Repo, Eveliina; Yin, Dulin; Meng, Yong; Jafari, Shila; Sillanpää, Mika

    2015-09-01

    The discharge of metals and dyes poses a serious threat to public health and the environment. What is worse, these two hazardous pollutants are often found to coexist in industrial wastewaters, making the treatment more challenging. Herein, we report an EDTA-cross-linked β-cyclodextrin (EDTA-β-CD) bifunctional adsorbent, which was fabricated by an easy and green approach through the polycondensation reaction of β-cyclodextrin with EDTA as a cross-linker, for simultaneous adsorption of metals and dyes. In this setting, cyclodextrin cavities are expected to capture dye molecules through the formation of inclusion complexes and EDTA units as the adsorption sites for metals. The adsorbent was characterized by FT-IR, elemental analysis, SEM, EDX, ζ-potential, and TGA. In a monocomponent system, the adsorption behaviors showed a monolayer adsorption capacity of 1.241 and 1.106 mmol g(-1) for Cu(II) and Cd(II), respectively, and a heterogeneous adsorption capacity of 0.262, 0.169, and 0.280 mmol g(-1) for Methylene Blue, Safranin O, and Crystal Violet, respectively. Interestingly, the Cu(II)-dye binary experiments showed adsorption enhancement of Cu(II), but no significant effect on dyes. The simultaneous adsorption mechanism was further confirmed by FT-IR, thermodynamic study, and elemental mapping. Overall, its facile and green fabrication, efficient sorption performance, and excellent reusability indicate that EDTA-β-CD has potential for practical applications in integrative and efficient treatment of coexistenting toxic pollutants.

  2. Scanning electron microscopy subsequent to a combined treatment of NaOCl and EDTA in some non-collagenous calcified matrixes.

    PubMed

    Kodaka, T; Sano, T; Mori, R

    2000-01-01

    Using backscattered electron (BSE) imaging and scanning electron microscopy, subsequent to a combined treatment of sodium hypochlorite (NaOCl) and ethylenediamine tetra-acetic acid (EDTA) or only with EDTA etching, we observed some structures of non-collagenous calcified matrixes with the aim of revealing the correlation of deposition between calcification degree and organic amount. In human tooth enamel, the NaOCl-EDTA method eroded more intensively the hypocalcified prisms of enamel tufts containing a relatively large amount of EDTA-insoluble organic matter than the hypercalcified normal prismatic enamel containing a small amount of the organic matter. Afibrillar cementum, one of the non-collagenous calcified tissues similar to the enamel, has been reported to consist of organic-rich and poor incremental lamellae. The BSE imaging showed an alternation pattern of hypocalcification and hypercalcification. The hypocalcified lamellae were retained by EDTA etching, while the hypercalcified lamellae showed a resistance against the NaOCl-EDTA method. In the non-collagenous calcareous concretions of human pineal body, organic-rich and poor, and hyper- and hypocalcified incremental lamellae have been reported. The deposition pattern of calcification degree and organic amount was similar to that in afibrillar cementum, and the hypercalcified lamellae showed a resistance against the NaOCl-EDTA method. In conclusion, the high and the lower calcified regions of non-collagenous calcified matrixes contained smaller and larger amounts of EDTA-insoluble organic matter respectively. Moreover, scanning electron microscopy subsequent to the NaOCl-EDTA method corresponding to the BSE imaging clearly showed fine calcified structures compared with the BSE imaging. PMID:10791437

  3. Reasons for raising the maximum acceptable daily intake of EDTA and the benefits for iron fortification of foods for children 6-24 months of age.

    PubMed

    Wreesmann, Carel Theo Jozef

    2014-10-01

    The current maximum acceptable daily intake (ADI) of ethylenediaminetetraacetic acid (EDTA) of 1.9 mg day(-1) per kilogram bodyweight (mg day(-1)  kgbw(-1) ) limits the daily intake of iron as iron EDTA [ferric sodium EDTA; sodium iron(III) EDTA] to approximately 2-2.5 mg day(-1) for children 6-24 months of age. This limit was defined by the Joint FAO/WHO Expert Committee on Food Additives (JECFA) in 1973 based on data from an animal-feed study published in 1963. Other animal studies indicate that this limit can be raised to 4.4 or possibly up to 21.7 mg day(-1)  kgbw(-1) , which is 2.3-11.4 times higher than the current value. For nearly 50 years, iron EDTA has been used in France in medicinal syrup for infants 1-6 months of age. The maximum recommended dosage of this drug is 37 times higher than the maximum ADI of EDTA. No adverse health effects have been reported as a result of this medicinal consumption of iron EDTA. Raising the maximum ADI of EDTA to only 4.4 mg day(-1)  kgbw(-1) would enable iron EDTA, an iron fortificant with proven bioavailability in phytate-rich meals, to be added in adequate amounts to cereal-based meals for children 6-24 months of age, who are at risk of iron deficiency.

  4. Adsorption of hydroxamate siderophores and EDTA on goethite in the presence of the surfactant sodium dodecyl sulfate

    PubMed Central

    2009-01-01

    Siderophore-promoted iron acquisition by microorganisms usually occurs in the presence of other organic molecules, including biosurfactants. We have investigated the influence of the anionic surfactant sodium dodecyl sulfate (SDS) on the adsorption of the siderophores DFOB (cationic) and DFOD (neutral) and the ligand EDTA (anionic) onto goethite (α-FeOOH) at pH 6. We also studied the adsorption of the corresponding 1:1 Fe(III)-ligand complexes, which are products of the dissolution process. Adsorption of the two free siderophores increased in a similar fashion with increasing SDS concentration, despite their difference in molecule charge. In contrast, SDS had little effect on the adsorption of EDTA. Adsorption of the Fe-DFOB and Fe-DFOD complexes also increased with increasing SDS concentrations, while adsorption of Fe-EDTA decreased. Our results suggest that hydrophobic interactions between adsorbed surfactants and siderophores are more important than electrostatic interactions. However, for strongly hydrophilic molecules, such as EDTA and its iron complex, the influence of SDS on their adsorption seems to depend on their tendency to form inner-sphere or outer-sphere surface complexes. Our results demonstrate that surfactants have a strong influence on the adsorption of siderophores to Fe oxides, which has important implications for siderophore-promoted dissolution of iron oxides and biological iron acquisition. PMID:19523232

  5. Calcium-activated gene transfection from DNA/poly(amic acid-co-imide) complexes.

    PubMed

    Wu, Szu-Yuan; Chang, Li-Ting; Peng, Sydeny; Tsai, Hsieh-Chih

    2015-01-01

    In this study, we synthesized a water-soluble poly(amic acid-co-imide) (PA-I) from ethylenediaminetetraacetic dianhydride (EDTA) and 2,2'-(ethylenedioxy)bis(ethylamine) that possesses comparable transfection efficiency to that of polyethylenimine (PEI), when prepared in combination with divalent calcium cations. The polycondensation of monomers afforded poly(amic acid) (PA) precursors, and subsequent thermal imidization resulted in the formation of PA-I. At a polymer/DNA ratio (indicated by the molar ratio of nitrogen in the polymer to phosphate in DNA) of 40, complete retardation of the DNA band was observed by gel electrophoresis, indicating the strong association of DNA with PA-I. A zeta potential of -22 mV was recorded for the PA-I polymer solution, and no apparent cytotoxicity was observed at concentrations up to 500 μg·mL(-1). In the presence of divalent Ca(2+), the transfection efficiency of PA-I was higher than that of PA, due to the formation of a copolymer/Ca(2+)/DNA polyplex and the reduction in negative charge due to thermal cyclization. Interestingly, a synergistic effect of Ca(2+) and the synthesized copolymer on DNA transfection was observed. The use of Ca(2+) or copolymer alone resulted in unsatisfactory delivery, whereas the formation of three-component polyplexes synergistically increased DNA transfection. Our findings demonstrated that a PA-I/Ca(2+)/DNA polyplex could serve as a promising candidate for gene delivery.

  6. Preparation and investigation of acetyl salicylic acid-caffeine complex for rectal administration.

    PubMed

    Fouad, Ehab A; El-Badry, Mahmoud; Alanazi, Fars K; Arafah, Maha M; Al-Ashban, Riyadh; Alsarra, Ibrahim A

    2010-06-01

    An acetyl salicylic acid-caffeine complex was prepared and evaluated for the potential use in rectal administration. The results revealed the formation of a complex between acetyl salicylic acid and caffeine in a 1:1 molar ratio by a charge transfer mechanism. The effects of acetyl salicylic acid and complex on the rectal tissues showed destruction in the mucosal epithelium in case of acetyl salicylic acid; however, no change in the rectal tissues was noticed upon the administration of the complex. The effect of suppository bases on the release of the complex was studied using Witepsol H15 as fatty base and polyethylene glycols (PEG) 1000 and 4000 as a water soluble suppository base. The release profiles of acetyl salicylic acid and the complex were faster from PEG than from that of Witepsol H15. The percent release for the complex and acetyl salicylic acid from PEG base were 45.8, and 34.9%, respectively. However, it was 8.7 and 7.8%, respectively, from Witepsol H15 fatty base. The release kinetic was found to follow the non-Fickian diffusion model for complex from the suppository bases. It was concluded that acetyl salicylic acid caffeine complex can be used safely for rectal administration.

  7. Effects of chemical and enzymatic modifications on starch-oleic acid complex formation.

    PubMed

    Arijaje, Emily Oluwaseun; Wang, Ya-Jane

    2015-04-29

    The solubility of starch-inclusion complexes affects the digestibility and bioavailability of the included molecules. Acetylation with two degrees of substitution, 0.041 (low) and 0.091 (high), combined without or with a β-amylase treatment was employed to improve the yield and solubility of the inclusion complex between debranched potato starch and oleic acid. Both soluble and insoluble complexes were recovered and analyzed for their degree of acetylation, complexation yields, molecular size distributions, X-ray diffraction patterns, and thermal properties. Acetylation significantly increased the amount of recovered soluble complexes as well as the complexed oleic acid in both soluble and insoluble complexes. High-acetylated debranched-only starch complexed the highest amount of oleic acid (38.0 mg/g) in the soluble complexes; low-acetylated starch with or without the β-amylase treatment resulted in the highest complexed oleic acid in the insoluble complexes (37.6-42.9 mg/g). All acetylated starches displayed the V-type X-ray pattern, and the melting temperature generally decreased with acetylation. The results indicate that starch acetylation with or without the β-amylase treatment can improve the formation and solubility of the starch-oleic acid complex. PMID:25877005

  8. Stability Constants of Mixed Ligand Complexes of Nickel(II) with Adenine and Some Amino Acids

    PubMed Central

    Türkel, Naciye

    2015-01-01

    Nickel is one of the essential trace elements found in biological systems. It is mostly found in nickel-based enzymes as an essential cofactor. It forms coordination complexes with amino acids within enzymes. Nickel is also present in nucleic acids, though its function in DNA or RNA is still not clearly understood. In this study, complex formation tendencies of Ni(II) with adenine and certain L-amino acids such as aspartic acid, glutamic acid, asparagine, leucine, phenylalanine, and tryptophan were investigated in an aqueous medium. Potentiometric equilibrium measurements showed that both binary and ternary complexes of Ni(II) form with adenine and the above-mentioned L-amino acids. Ternary complexes of Ni(II)-adenine-L-amino acids are formed by stepwise mechanisms. Relative stabilities of the ternary complexes are compared with those of the corresponding binary complexes in terms of Δlog10⁡K, log10⁡X, and % RS values. It was shown that the most stable ternary complex is Ni(II):Ade:L-Asn while the weakest one is Ni(II):Ade:L-Phe in aqueous solution used in this research. In addition, results of this research clearly show that various binary and ternary type Ni(II) complexes are formed in different concentrations as a function of pH in aqueous solution. PMID:26843852

  9. Recovery of nickel and cobalt from organic acid complexes: adsorption mechanisms of metal-organic complexes onto aminophosphonate chelating resin.

    PubMed

    Deepatana, A; Valix, M

    2006-09-21

    This study examined the recovery of nickel and cobalt from organic acid complexes using a chelating aminophosphonate Purolite S950 resin. These metal complexes are generated by bioleaching nickel laterite ores, a commercial nickel and cobalt mineral oxide, with heterotrophic organism and their metabolites or organic acid products. Equilibrium adsorption tests were conducted as a function of Ni and Co concentrations (15-2000 mg/L), solution pH (0.01 and 0.1 M acids) and three metabolic complexing agents (citrate, malate and lactate). It was shown that the adsorption of the various Ni- and Co-complexes on Purolite were quite low, 16-18 and 5.4-9 mg/g of resin, respectively, in comparison to the smaller nickel ions and nickel sulfate. This was attributed to the bulky organic ligands which promoted crowding effect or steric hindrance. The adsorption of these complexes was further hampered by the strong affinity of the resin to H+ ions under acidic conditions. Mechanisms of adsorption, as inferred from the fitted empirical Langmuir and Freundlich models, were correlated to the proposed steric hindrance and competitive adsorption effects. Nickel and cobalt elution from the resin were found be effective and were independent of the type of metal complexes and metal concentrations. This study demonstrated the relative challenges involved in recovering nickel and cobalt from bioleaching solutions. PMID:16698178

  10. Recovery of nickel and cobalt from organic acid complexes: adsorption mechanisms of metal-organic complexes onto aminophosphonate chelating resin.

    PubMed

    Deepatana, A; Valix, M

    2006-09-21

    This study examined the recovery of nickel and cobalt from organic acid complexes using a chelating aminophosphonate Purolite S950 resin. These metal complexes are generated by bioleaching nickel laterite ores, a commercial nickel and cobalt mineral oxide, with heterotrophic organism and their metabolites or organic acid products. Equilibrium adsorption tests were conducted as a function of Ni and Co concentrations (15-2000 mg/L), solution pH (0.01 and 0.1 M acids) and three metabolic complexing agents (citrate, malate and lactate). It was shown that the adsorption of the various Ni- and Co-complexes on Purolite were quite low, 16-18 and 5.4-9 mg/g of resin, respectively, in comparison to the smaller nickel ions and nickel sulfate. This was attributed to the bulky organic ligands which promoted crowding effect or steric hindrance. The adsorption of these complexes was further hampered by the strong affinity of the resin to H+ ions under acidic conditions. Mechanisms of adsorption, as inferred from the fitted empirical Langmuir and Freundlich models, were correlated to the proposed steric hindrance and competitive adsorption effects. Nickel and cobalt elution from the resin were found be effective and were independent of the type of metal complexes and metal concentrations. This study demonstrated the relative challenges involved in recovering nickel and cobalt from bioleaching solutions.

  11. Influence of phytase, EDTA, and polyphenols on zinc absorption in adults from porridges fortified with zinc sulfate or zinc oxide.

    PubMed

    Brnić, Marica; Wegmüller, Rita; Zeder, Christophe; Senti, Gabriela; Hurrell, Richard F

    2014-09-01

    Fortification of cereal staples with zinc is recommended to combat zinc deficiency. To optimize zinc absorption, strategies are needed to overcome the inhibitory effect of phytic acid (PA) and perhaps polyphenols. Five zinc absorption studies were conducted in young adults consuming maize or sorghum porridges fortified with 2 mg zinc as zinc sulfate (ZnSO4) or zinc oxide (ZnO) and containing combinations of PA or polyphenols as potential inhibitors and EDTA and phytase as potential enhancers. Fractional absorption of zinc (FAZ) was measured by using the double isotopic tracer ratio method. Adding phytase to the maize porridge immediately before consumption or using phytase for dephytinization during meal preparation both increased FAZ by >80% (both P < 0.001). Adding Na2EDTA at an EDTA:zinc molar ratio of 1:1 increased FAZ from maize porridge fortified with ZnSO4 by 30% (P = 0.01) but had no influence at higher EDTA ratios or on absorption from ZnO. FAZ was slightly higher from ZnSO4 than from ZnO (P = 0.02). Sorghum polyphenols had no effect on FAZ from dephytinized sorghum porridges but decreased FAZ by 20% from PA-rich sorghum porridges (P < 0.02). The combined inhibitory effect of polyphenols and PA was overcome by EDTA. In conclusion, ZnSO4 was better absorbed than ZnO, phytase used to degrade PA during digestion or during food preparation substantially increased zinc absorption from zinc-fortified cereals, EDTA at a 1:1 molar ratio modestly enhanced zinc absorption from ZnSO4-fortified cereals but not ZnO-fortified cereals, and sorghum polyphenols inhibited zinc absorption in the presence, but not absence, of PA. This trial was registered at clinicaltrials.gov as NCT01210794.

  12. EDTA addition enhances bacterial respiration activities and hydrocarbon degradation in bioaugmented and non-bioaugmented oil-contaminated desert soils.

    PubMed

    Al Kharusi, Samiha; Abed, Raeid M M; Dobretsov, Sergey

    2016-03-01

    The low number and activity of hydrocarbon-degrading bacteria and the low solubility and availability of hydrocarbons hamper bioremediation of oil-contaminated soils in arid deserts, thus bioremediation treatments that circumvent these limitations are required. We tested the effect of Ethylenediaminetetraacetic acid (EDTA) addition, at different concentrations (i.e. 0.1, 1 and 10 mM), on bacterial respiration and biodegradation of Arabian light oil in bioaugmented (i.e. with the addition of exogenous alkane-degrading consortium) and non-bioaugmented oil-contaminated desert soils. Post-treatment shifts in the soils' bacterial community structure were monitored using MiSeq sequencing. Bacterial respiration, indicated by the amount of evolved CO2, was highest at 10 mM EDTA in bioaugmented and non-bioaugmented soils, reaching an amount of 2.2 ± 0.08 and 1.6 ± 0.02 mg-CO2 g(-1) after 14 days of incubation, respectively. GC-MS revealed that 91.5% of the C14-C30 alkanes were degraded after 42 days when 10 mM EDTA and the bacterial consortium were added together. MiSeq sequencing showed that 78-91% of retrieved sequences in the original soil belonged to Deinococci, Alphaproteobacteria, Gammaproteobacteia and Bacilli. The same bacterial classes were detected in the 10 mM EDTA-treated soils, however with slight differences in their relative abundances. In the bioaugmented soils, only Alcanivorax sp. MH3 and Parvibaculum sp. MH21 from the exogenous bacterial consortium could survive until the end of the experiment. We conclude that the addition of EDTA at appropriate concentrations could facilitate biodegradation processes by increasing hydrocarbon availability to microbes. The addition of exogenous oil-degrading bacteria along with EDTA could serve as an ideal solution for the decontamination of oil-contaminated desert soils.

  13. Synthesis and spectroscopic characterization of gallic acid and some of its azo complexes

    NASA Astrophysics Data System (ADS)

    Masoud, Mamdouh S.; Hagagg, Sawsan S.; Ali, Alaa E.; Nasr, Nessma M.

    2012-04-01

    A series of gallic acid and azo gallic acid complexes were prepared and characterized by elemental analysis, IR, electronic spectra and magnetic susceptibility. The complexes were of different geometries: Octahedral, Tetrahedral and Square Planar. ESR was studied for copper complexes. All of the prepared complexes were of isotropic nature. The thermal analyses of the complexes were studied by DTA and DSC techniques. The thermodynamic parameters and the thermal transitions, such as glass transitions, crystallization and melting temperatures for some ligands and their complexes were evaluated and discussed. The entropy change values, ΔS#, showed that the transition states are more ordered than the reacting complexes. The biological activities of some ligands and their complexes are tested against Gram positive and Gram negative bacteria. The results showed that some complexes have a well considerable activity against different organisms.

  14. Effects of chemical and enzymatic modifications on starch-stearic acid complex formation.

    PubMed

    Arijaje, Emily Oluwaseun; Wang, Ya-Jane; Shinn, Sara; Shah, Utkarsh; Proctor, Andrew

    2014-04-01

    Debranched unacetylated and acetylated potato starches with two degrees of substitution, 0.041 (low) and 0.078 (high), combined with or without β-amylase hydrolysis were prepared to form soluble and insoluble complexes with stearic acid. The effects of modifications on the complexation, thermal properties, and X-ray patterns of soluble and insoluble complexes were investigated. Acetylation decreased the recovery of insoluble complexes but increased that of soluble complexes. Low acetylated, β-amylase-treated starch had a significantly increased amount of complexed stearic acid (123.1 mg/g) for insoluble complexes; high acetylated, β-amylase-treated starch had the highest complexed stearic acid (61.2 mg/g) for the soluble complexes. The melting temperature of the complexes decreased with acetylation. All β-amylase-treated acetylated complexes displayed the V-type diffraction pattern with peaks at 2θ = 7.4°, 12.9°, and 20°. These results suggest that starch can be modified by acetylation, debranching, and/or β-amylase to produce significant quantities of soluble starch-stearic acid complexes.

  15. Nickel(II) and copper(II) complexes with humic acid anions and their derivatives

    SciTech Connect

    Ryabova, I.N.

    2008-01-15

    Complexation of Ni(II) and Cu(II) in aqueous solutions with anions of humic acids, extracted from naturally oxidized coal, and with their hydroxymethyl derivatives is studied spectrophotometrically and potentiometrically. The complexation stoichiometry and the stability constants of the complexes are determined.

  16. Telomerization of amino acids with butadiene, catalyzed by palladium complexes

    SciTech Connect

    Dzhemilev, U.M.; Fakhretdinov, R.N.; Telin, A.G.

    1987-01-10

    The telomerization of ..cap alpha..-, ..beta..-, ..gamma..-, and epsilon-amino acids having various structures with butadiene under the influence of the three-component palladium catalyst Pd(acac)/sub 2/-PPh/sub 3/-AlEt/sub 3/ was investigated in DMSO-toluene solution. The ..cap alpha..- and epsilon-aliphatic and also the ..cap alpha..-, ..beta..-, and ..gamma..-aromatic amino acids react with butadiene, giving the products from octadienylation at the amino group exclusively. Under the conditions of telomerization aliphatic ..beta..-amino acids are cleaved with the formation of unsaturated tertiary amines. In the case of aliphatic ..gamma..-amino acids it is possible to obtain telomers alkylated at the carbonyl group.

  17. An Experiment on Isomerism in Metal-Amino Acid Complexes.

    ERIC Educational Resources Information Center

    Harrison, R. Graeme; Nolan, Kevin B.

    1982-01-01

    Background information, laboratory procedures, and discussion of results are provided for syntheses of cobalt (III) complexes, I-III, illustrating three possible bonding modes of glycine to a metal ion (the complex cations II and III being linkage/geometric isomers). Includes spectrophotometric and potentiometric methods to distinguish among the…

  18. Sensitive NADH detection in a tumorigenic cell line using a nano-biosensor based on the organic complex formation.

    PubMed

    Akhtar, Mahmood H; Mir, Tanveer A; Gurudatt, N G; Chung, Saeromi; Shim, Yoon-Bo

    2016-11-15

    A robust amperometric sensor for β-nicotinamide adenine dinucleotide (NADH) detection was developed through the organic complex formation with ethylenediaminetetraacetic acid (EDTA) bonded on the polyethylenimine (PEI)/activated graphene oxide (AGO) layer. The EDTA immobilized sensor probe (GCE/AGO/PEI-EDTA) revealed a catalytic property towards NADH oxidation that allows for the highly sensitive electrochemical detection of NADH at a low oxidation potential. Surface characterization demonstrated that the negatively charged AGO acted as nanofillers in the positively charged PEI matrix through the charge interaction. The immobilization of EDTA on the polymer layer provided more surface area for NADH to interact with through the enhanced chemical interlocking between them. We observed the strong interaction between NADH and EDTA on the AGO/PEI layer using a quartz crystal microbalance (QCM), X-ray photoelectron spectroscopy (XPS), and the calculation of the minimized energy for complex formation. The dynamic range of NADH was determined to be between 0.05μM and 500μM with a detection limit (LD) of 20.0±1.1nM. The reliability of the developed sensor for biomedical applications was examined by detecting NADH in tumorigenic lung epithelial cells using the standard addition method. PMID:27209575

  19. The formic acid-nitric acid complex: microwave spectrum, structure, and proton transfer.

    PubMed

    Mackenzie, Rebecca B; Dewberry, Christopher T; Leopold, Kenneth R

    2014-09-11

    Rotational spectra are reported for seven isotopologues of the complex HCOOH-HNO3 in a supersonic jet. The system is planar and bound by a pair of hydrogen bonds, much like the more widely studied carboxylic acid dimers. Double proton exchange interconverts the system between a pair of equivalent structures, as revealed by a splitting of the a-type spectrum that disappears when one of the hydrogen bonding protons is replaced by deuterium. The observation of relative intensities that are consistent with nuclear spin statistics in a symmetric and antisymmetric pair of tunneling states provides additional evidence for such a motion. The observed splittings in the pure rotational spectrum are 1-2 orders of magnitude smaller than those recently reported in the pure rotational spectra of several related carboxylic acid dimers. This is a curious difference, although we note that because the observed spectra do not cross the tunneling doublet, the splittings are a measure of the difference in effective rotational constants for the two states, not the tunneling frequency itself. The observed rotational constants have been used to determine an accurate vibrationally averaged structure for the complex. The two hydrogen bond lengths, 1.686(17) Å and 1.813(10) Å for the hydrogen bonds involving the HNO3 and HCOOH protons, respectively, differ by 0.127(27) Å. Likewise, the associated oxygen-oxygen distances determined for the parent species, 2.631 and 2.794 Å, differ by 0.163 Å. These results suggest that the double proton transfer is necessarily accompanied by substantial motion of the heavy atom frame, and thus this system, in principle, provides an excellent prototype for multidimensional tunneling processes. Ab initio calculations of the binding energy and the barrier height are presented. Excellent agreement between the calculated equilibrium structure and the experimental, vibrationally averaged structure suggests that the vibrational wave function is not highly

  20. Evidence for a Complex Between Thf and Acetic Acid from Broadband Rotational Spectroscopy

    NASA Astrophysics Data System (ADS)

    Zaleski, Daniel P.; Bittner, Dror M.; Mullaney, John Connor; Stephens, Susanna L.; King, Adrian; Habgood, Matthew; Walker, Nick

    2015-06-01

    Evidence for a complex between tetrahydrofuran (THF) and acetic acid from broadband rotational spectroscopy will be presented. Transitions believed to belong to the complex were first identified in a gas mixture containing small amounts of THF, triethyl borane, and acetic acid balanced in argon. Ab initio calculations suggest a complex between THF and acetic acid is more likely to form compared to the analogous acetic acid complex with triethyl borane, the initial target. The observed rotational constants are also more similar to those predicted for a complex formed between THF and acetic acid, than for those of a complex formed between triethyl borane and acetic acid. Subsequently, multiple isotopologues of acetic acid have been measured, confirming its presence in the structure. No information has yet been obtained through isotopic substitution within the THF sub-unit. Ab initio calculations predict the most likely structure is one where the acetic acid subunit coordinates over the ring creating a "bridge" between the THF oxygen, the carboxylic O-H, and the carbonyl oxygen to a hydrogen atom on the back of the ring.

  1. Design of stereoelectronically promoted super lewis acids and unprecedented chemistry of their complexes.

    PubMed

    Foroutan-Nejad, Cina; Vicha, Jan; Marek, Radek

    2014-09-01

    A new family of stereoelectronically promoted aluminum and scandium super Lewis acids is introduced on the basis of state-of-the-art computations. Structures of these molecules are designed to minimize resonance electron donation to central metal atoms in the Lewis acids. Acidity of these species is evaluated on the basis of their fluoride-ion affinities relative to the antimony pentafluoride reference system. It is demonstrated that introduced changes in the stereochemistry of the designed ligands increase acidity considerably relative to Al and Sc complexes with analogous monodentate ligands. The high stability of fluoride complexes of these species makes them ideal candidates to be used as weakly coordinating anions in combination with highly reactive cations instead of conventional Lewis acid-fluoride complexes. Further, the interaction of all designed molecules with methane is investigated. All studied acids form stable pentavalent-carbon complexes with methane. In addition, interactions of the strongest acid of this family with very weak bases, namely, H2, N2, carbon oxides, and noble gases were investigated; it is demonstrated that this compound can form considerably stable complexes with the aforementioned molecules. To the best of our knowledge, carbonyl and nitrogen complexes of this species are the first hypothetical four-coordinated carbonyl and nitrogen complexes of aluminum. The nature of bonding in these systems is studied in detail by various bonding analysis approaches.

  2. Complexation of U(VI) with 1-Hydroxyethane-1,1-diphosphonicAcid (HEDPA) in Acidic to Basic Solutions

    SciTech Connect

    Reed, W A; Rao, L; Zanonato, P; Garnov, A; Powell, B A; Nash, K L

    2007-01-24

    Complexation of U(VI) with 1-hydroxyethane-1,1-diphosphonic acid (HEDPA) in acidic to basic solutions has been studied with multiple techniques. A number of 1:1 (UO{sub 2}H{sub 3}L), 1:2 (UO{sub 2}H{sub j}L{sub 2} where j = 4, 3, 2, 1, 0 and -1) and 2:2 ((UO{sub 2}){sub 2}H{sub j}L{sub 2} where j = 1, 0 and -1) complexes form, but the 1:2 complexes are the major species in a wide pH range. Thermodynamic parameters (formation constants, enthalpy and entropy of complexation) were determined by potentiometry and calorimetry. Data indicate that the complexation of U(VI) with HEDPA is exothermic, favored by the enthalpy of complexation. This is in contrast to the complexation of U(VI) with dicarboxylic acids in which the enthalpy term usually is unfavorable. Results from electrospray ionization mass spectrometry (ESI-MS) and {sup 31}P NMR have confirmed the presence of 1:1, 1:2 and 2:2 U(VI)-HEDPA complexes.

  3. [Thermodynamic characteristics of nucleic acid complexes with silver ions].

    PubMed

    Minasian, K A; Poletaev, A I; Borob'ev, A F

    1981-01-01

    By means of mixing reaction calorimetry the enthalpy of the complexes formation between Ag+ ions and DNA and dsRNA was measured. It was shown that Ag+ ions are able to form two types of complexes (I and II) with dsRNA. Using the method of the competitive reaction with chloride ions the stability constants of complex formation were obtained for dsRNA-Ag+ complexes for different temperatures. These measurements gave the delta H and delta S values for both complexes: delta HI = -74,9 +/- 7,1 kjouls/mol, delta SI = -100.0 +/- 25.0 jouls/mol deg; delta HII = -39,8 +/- 4,2 kjouls/mol, delta SII = +2 +/- 14 jouls/mol deg. The calorimetric results of delta H determination are the same within the limits of experimental errors. The enthalpy term of dsRNA-Ag+ complexes proved to bring the main contribution into the free energy of complex formation.

  4. EDTA ameliorates phytoextraction of lead and plant growth by reducing morphological and biochemical injuries in Brassica napus L. under lead stress.

    PubMed

    Kanwal, Urooj; Ali, Shafaqat; Shakoor, Muhammad Bilal; Farid, Mujahid; Hussain, Sabir; Yasmeen, Tahira; Adrees, Muhammad; Bharwana, Saima Aslam; Abbas, Farhat

    2014-01-01

    Brassica species are very effective in remediation of heavy metal contaminated sites. Lead (Pb) as a toxic pollutant causes number of morphological and biochemical variations in the plants. Synthetic chelator such as ethylenediaminetetraacetic acid (EDTA) improves the capability of plants to uptake heavy metals from polluted soil. In this regard, the role of EDTA in phytoextraction of lead, the seedlings of Brassica napus L. were grown hydroponically. Lead levels (50 and 100 μM) were supplied alone or together with 2.5 mM EDTA in the nutrient culture. After 7 weeks of stress, plants indicated that toxicity of Pb caused negative effects on plants and significantly reduced growth, biomass, chlorophyll content, gas exchange characteristics, and antioxidant enzymes activities such as superoxide dismutase (SOD), guaiacol peroxidase (POD), ascorbate peroxidase (APX), and catalase (CAT). Exposure to Pb induced the malondialdehyde (MDA), and hydrogen peroxide (H2O2) generation in both shoots and roots. The addition of EDTA alone or in combination with Pb significantly improved the plant growth, biomass, gas exchange characteristics, chlorophyll content, and antioxidant enzymes activities. EDTA also caused substantial improvement in Pb accumulation in Brassica plants. It can be deduced that application of EDTA significantly lessened the adverse effects of lead toxicity. Additionally, B. napus L. exhibited greater degree of tolerance against Pb toxicity and it also accumulated significant concentration of Pb from media. PMID:24854501

  5. Studies of chemical reduction of Fe(III)*EDTA in an SO{sub 2}/NO{sub x} aqueous scrubber system

    SciTech Connect

    Li, W.; Keener, T.C.; Mendelsohn, M.; Harkness, J.B.L.; Livengood, C.D.

    1996-03-01

    Ferrous*EDTA has been found to be an effective scrubbing agent for nitric oxide gas. A major process problem is oxidation of the iron to the ferric species, leading to a significant decrease in NO{sub x}-removal capability. Argonne National Laboratory discovered a class of organic compounds that, when used with ferrous*EDTA in a sodium carbonate chemistry, could maintain high levels of NO{sub x} removal. However, those antioxidant/reducing agents (A/R) are not effective in a lime-based chemistry. In recent reports, it has been found that ascorbic acid and related compounds are capable of maintaining stable NO{sub x} removals of about 50% (compared with about 15% without the agent) in a lime-based FGD chemistry with Fe(II)*EDTA. It is believed that the improved performance of Fe(II)*EDTA is due to the catalytic action of ascorbate in the Fe(III)*EDTA reduction system, where Fe(III)*EDTA is reduced by ascorbate and oxidized ascorbate is then reduced back to the ascorbate by sulfite/bisulfite anions, which come from the dissolution of SO{sub 2} in the flue gas. In the present work, the kinetics of the reduction of ferric chelate by ascorbate and reduction of oxidized ascorbate by sulfite/bisulfite anions at a typical flue-gas scrubber-system operating temperature ({approximately}55 C) have been determined.

  6. Polymers with complexing properties. Simple poly(amino acids)

    NASA Technical Reports Server (NTRS)

    Roque, J. M.

    1978-01-01

    The free amino (0.3 equiv/residue) and carboxyl (0.5 equiv/residue) groups of thermal polylysine increased dramatically on treatment with distilled water. The total hydrolysis of such a polymer was abnormal in that only about 50% of the expected amino acids were recovered. Poly (lysine-co-alanine-co-glycine) under usual conditions hydrolyzed completely in 8 hours; whereas, when it was pretreated with diazomethane, a normal period of 24 hours was required to give (nearly) the same amounts of each free amino acid as compared with those obtained from the untreated polymer. The amino groups of the basic thermal poly(amino acids) were sterically hindered. The existence of nitrogen atoms linking two or three chains and reactive groups (anhydride, imine) were proposed.

  7. Crystal and molecular structure of Sr{sub 2}(Edta) . 5H{sub 2}O, Sr{sub 2}(H{sub 2}Edta)(HCO{sub 3}){sub 2} . 4H{sub 2}O, and Sr{sub 2}(H{sub 2}Edta)Cl{sub 2} . 5H{sub 2}O strontium ethylenediaminetetraacetates

    SciTech Connect

    Polyakova, I. N.; Poznyak, A. L.; Sergienko, V. S.

    2009-03-15

    Three Sr{sup 2+} compounds with the Edta{sup 4-} and H{sub 2}Edta{sup 2-} ligands-Sr{sub 2}(Edta) . 5H{sub 2}O (I), Sr{sub 2}(H{sub 2}Edta)(HCO{sub 3}){sub 2} . 4H{sub 2}O (II), and Sr{sub 2}(H{sub 2}Edta)Cl{sub 2} . 5H{sub 2}O (III)-are synthesized, and their crystal structures are studied. In I, the Sr(1) atom is coordinated by the hexadentate Edta{sup 4-} ligand following the 2N + 4O pattern and by two O atoms of the neighboring ligands, which affords the formation of zigzag chains. The Sr(2) atom forms bonds with O atoms of five water molecules and attaches itself to a chain via bonds with three O atoms of the Edta{sup 4-} ligands. The Sr(1)-O and Sr(2)-O bond lengths fall in the ranges 2.520(2)-2.656(3) and 2.527(3)-2.683(2) A, respectively. The Sr(1)-N bonds are 2.702(3) and 2.743(3) A long. In II and III, the H{sub 2}Edta{sup 2-} anions have a centrosymmetric structure with the trans configuration of the planar ethylenediamine fragment. The N atoms are blocked by acid protons. In II, the environment of the Sr atom is formed by six O atoms of three H{sub 2}Edta ligands, two O atoms of water molecules, and an O atom of the bicarbonate ion, which is disordered over two positions. In III, the environment of the Sr atom includes six O atoms of four H{sub 2}Edta{sup 2-} ligands and three O atoms of water molecules. The coordination number of the Sr atoms is equal to 8 + 1. In II and III, the main bonds fall in the ranges 2.534(3)-2.732(2) and 2.482(2)-2.746(3) A, whereas the ninth bond is elongated to 2.937(3) and 3.055(3) A, respectively. In II, all the structural elements are linked into wavy layers. The O-H-O interactions contribute to the stabilization of the layer and link neighboring layers. In III, hydrated Sr{sup 2+} cations and H{sub 2}Edta{sup -} anions form a three-dimensional [Sr{sub 2}(H{sub 2}Edta)(H{sub 2}O){sub 3}]{sub n}{sup 2n+} framework. The Cl{sup -} anions are fixed in channels of the framework by hydrogen bonds with four water molecules. In

  8. EDTA chelation therapy, without added vitamin C, decreases oxidative DNA damage and lipid peroxidation.

    PubMed

    Roussel, Anne Marie; Hininger-Favier, Isabelle; Waters, Robert S; Osman, Mireille; Fernholz, Karen; Anderson, Richard A

    2009-03-01

    Chelation therapy is thought to not only remove contaminating metals but also to decrease free radical production. However, in standard ethylene diamine tetracetic acid (EDTA) chelation therapy, high doses of vitamin C with potential pro-oxidant effects are often added to the chelation solution. The authors demonstrated previously that the intravenous administration of the standard chelation cocktail, containing high amounts of vitamin C, resulted in an acute transitory pro-oxidant burst that should be avoided in the treatment of pathologies at risk of increased oxidative stress such as diabetes and cardiovascular disease. The current study was designed to determine the acute and chronic biochemical effects of chelation therapy on accepted clinical, antioxidant variables. An EDTA chelation cocktail not containing ascorbic acid was administered to six adult patients for five weeks (10 sessions of chelation therapy); antioxidant indicators were monitored. Immediately after the initial chelation session, in contrast with the data previously reported with the standard cocktail containing high doses of vitamin C, none of the oxidative stress markers were adversely modified. After five weeks, plasma peroxide levels, monitored by malondialdehyde, decreased by 20 percent, and DNA damage, monitored by formamidopyrimidine-DNA glycosylase (Fpg) sensitive sites, decreased by 22 percent. Remaining antioxidant-related variables did not change. In summary, this study demonstrates that multiple sessions of EDTA chelation therapy in combination with vitamins and minerals, but without added ascorbic acid, decreases oxidative stress. These results should be beneficial in the treatment of diseases associated with increased oxidative stress such as diabetes and cardiovascular diseases.

  9. Meat and ascorbic acid can promote Fe availability from Fe-phytate but not from Fe-tannic acid complexes.

    PubMed

    Engle-Stone, Reina; Yeung, Andrew; Welch, Ross; Glahn, Raymond

    2005-12-28

    This study utilized an in vitro digestion/Caco-2 cell model to determine the levels of ascorbic acid (AA) and "meat factor" needed to promote Fe absorption from Fe complexed with phytic acid (PA) or tannic acid (TA). AA reversed the inhibition of Fe absorption by PA beginning at a molar ratio of 1:20:1 (Fe:PA:AA) but essentially had no effect on the Fe complexed with TA. Fish also reversed the inhibition of Fe uptake by PA but not by TA. TA and fish decreased total Fe solubility. Iron in the presence of PA was highly soluble. AA, but not fish, increased the percentage of soluble Fe as Fe2+ in the presence of both inhibitors. The results indicate that monoferric phytate is a form of Fe that can be available for absorption in the presence of uptake promoters. In contrast, a TA-Fe complex is much less soluble and unavailable in the presence of promoters.

  10. Transition Metal Complexes of Phosphinous Acids Featuring a Quasichelating Unit: Synthesis, Characterization, and Hetero-bimetallic Complexes.

    PubMed

    Allefeld, Nadine; Bader, Julia; Neumann, Beate; Stammler, Hans-Georg; Ignat'ev, Nikolai; Hoge, Berthold

    2015-08-17

    Diorganophosphane oxides were employed as preligands for the synthesis of catalytically active transition metal complexes of the phosphinous acids (CF3)2POH and (C2F5)2POH. Their reactions with solid PtCl2 and PdCl2 led to the formation of mononuclear phosphinous acid complexes [Cl2M{P(R(f))2OH}2] (M = Pd, Pt; R(f) = C2F5, CF3), which can be crystallized, for example, as its pyridinium salts, 2[HPy](+)[Cl2Pd{P(CF3)2O}2](2-). In vacuo HCl is liberated from the neutral palladium complexes affording mixtures of di- and polynuclear complexes. Moreover, (C2F5)2POH was reacted with several β-diketonato complexes of palladium, platinum, and nickel yielding air- and moisture-stable complexes [(acac)M{[P(R(f))2O]2H}], featuring a quasichelating phosphinous acid phosphinito unit {P(R(f))2O···H···O(R(f))2P}(-). Treatment of [Ni(Cp)2] (Cp = cyclopentadienyl) and [(cod)RhCl]2 (cod = 1,5-cyclooctadiene) with (C2F5)2POH leads to the substitution of one Cp or chloro ligand by a quasichelating unit. The novel coordination compounds were characterized by NMR and IR spectroscopies, mass spectrometry, and X-ray diffraction analysis. The platinum complex [(acac)Pt{[P(C2F5)2O]2H}] (acac = acetylacetonato) was used for the construction of hetero-bimetallic complexes by the treatment with [(cod)RhCl]2 and [Ni(Cp)2]. The trinuclear bimetallic complex [{(acac)Pt[P(C2F5)2O]2}2Ni] is the first structurally characterized hetero-bimetallic species containing a bis(perfluoroalkyl)phosphinito bridge.

  11. Supramolecular adducts based on weak interactions between the trimeric Lewis acid complex (perfluoro-ortho-phenylene)mercury and polypnictogen complexes.

    PubMed

    Fleischmann, Martin; Jones, James S; Balázs, Gábor; Gabbaï, François P; Scheer, Manfred

    2016-09-21

    Reactions of the trinuclear Lewis acid perfluoro-ortho-phenylene)mercury [(o-HgC6F4)3] (1) with the polypnictogen complex [CpMo(CO)2(η(3)-P3)] (2) containing a cyclo-P3 ligand and the series of E2 complexes [{CpMo(CO)2}2(μ,η(2):η(2)-E2)] (E = P(3a), As(3b), Sb(3c), Bi(3d)) are reported. In all cases, the reaction products show very weak interactions between the En ligand complexes and the Lewis acid 1, as evidenced by their highly dynamic behaviour in solution and the formation of adducts in the solid state showing HgE contacts below the respective sum of the van der Waals radii. The complexes 2 (P3), 3a (P2) and 3b (As2) show interactions of only one pnictogen atom with all three Hg atoms of 1. The complex 3c (Sb2) forms two adducts with 1 showing either a side-on coordination of the Sb2 dumbbell towards Hg or an end-on coordination of both Sb atoms towards two independent molecules of 1. The Bi2 complex 3d shows an almost parallel alignment of the Bi2 dumbbell situated above the center of the planar Lewis acid 1. The arrangements of the E2 complex series towards 1 are rationalized with the help of electrostatic potential maps obtained by DFT calculations. Finally the structural characterizations of a new modification of the free Sb2 complex 3c, the Bi2 complex 3d, the starting material of its preparation [Bi{CpMo(CO)3}3] (4) and an unprecedented 'Cr4As5' cluster 5 are presented. PMID:27461890

  12. Analysis of complexes pairing hydroperoxyl radical with peroxyformic acid.

    PubMed

    Solimannejad, Mohammad; Shirazi, Sanaz G; Scheiner, Steve

    2007-10-25

    Ab initio quantum calculations are used to analyze the binding of complexes pairing OOH with HOOCHO. Six minima are located on the potential energy surface, all of cyclic geometry. Of particular interest are the OH...O and CH...O H-bonds that arise in the complexes and the manner in which these interactions influence the internal properties of the subunits. The analysis is complicated by the presence of an intramolecular H-bond in the unperturbed HOOCHO molecule, which must be broken in order to form the pair of intermolecular H-bonds that are responsible for the binding in the most stable complex. The CH bond of HOOCHO is contracted, and its stretching frequency undergoes a blue shift, when this group participates in a H-bond. PMID:17914777

  13. Calcium-activated gene transfection from DNA/poly(amic acid-co-imide) complexes

    PubMed Central

    Wu, Szu-Yuan; Chang, Li-Ting; Peng, Sydeny; Tsai, Hsieh-Chih

    2015-01-01

    In this study, we synthesized a water-soluble poly(amic acid-co-imide) (PA-I) from ethylenediaminetetraacetic dianhydride (EDTA) and 2,2′-(ethylenedioxy)bis(ethylamine) that possesses comparable transfection efficiency to that of polyethylenimine (PEI), when prepared in combination with divalent calcium cations. The polycondensation of monomers afforded poly(amic acid) (PA) precursors, and subsequent thermal imidization resulted in the formation of PA-I. At a polymer/DNA ratio (indicated by the molar ratio of nitrogen in the polymer to phosphate in DNA) of 40, complete retardation of the DNA band was observed by gel electrophoresis, indicating the strong association of DNA with PA-I. A zeta potential of −22 mV was recorded for the PA-I polymer solution, and no apparent cytotoxicity was observed at concentrations up to 500 μg·mL−1. In the presence of divalent Ca2+, the transfection efficiency of PA-I was higher than that of PA, due to the formation of a copolymer/Ca2+/DNA polyplex and the reduction in negative charge due to thermal cyclization. Interestingly, a synergistic effect of Ca2+ and the synthesized copolymer on DNA transfection was observed. The use of Ca2+ or copolymer alone resulted in unsatisfactory delivery, whereas the formation of three-component polyplexes synergistically increased DNA transfection. Our findings demonstrated that a PA-I/Ca2+/DNA polyplex could serve as a promising candidate for gene delivery. PMID:25767385

  14. Hydrogen bonds in 1:1 complex of piperidine-3-carboxylic acid with salicylic acid

    NASA Astrophysics Data System (ADS)

    Bartoszak-Adamska, Elżbieta; Dega-Szafran, Zofia; Krociak, Magdalena; Jaskolski, Mariusz; Szafran, Mirosław

    2009-02-01

    The 1:1 complex between the zwitterionic piperidinium-3-carboxylate (P3C) and salicylic acid (SAL), P3C·SAL, has been characterized by single crystal X-ray analysis, FTIR and NMR spectroscopy, and by DFT calculations. The crystals are orthorhombic, space group Pbca, with a = 11.6477(7), b = 9.1754(6), c = 23.5833(12) Å. An O sbnd H⋯O bridge (2.537(1) Å) links the SAL and P3C moieties. The proton in this H bond is located closer to the salicylic carboxylate group. In the P3C moiety, the piperidine ring adopts the chair conformation, and the carboxylate group is in the axial orientation and is stabilized by an intramolecular N +sbnd H⋯O hydrogen bond of 2.847(1) Å. In the crystal packing, two P3C·SAL units form a centrosymmetric dimer through a pair of intermolecular N +sbnd H⋯O bonds of 2.801(1) Å. The dimers form a zigzag chain linked via another N +sbnd H⋯O bond (2.799(1) Å). In the structures of the monomeric [P3C·SAL] and dimeric [(P3C·SAL) 2] species optimized by B3LYP/6-31G(d,p) calculations, both the inter- and intra-molecular hydrogen bonds are shorter than in the crystal. The FTIR spectrum shows a broad absorption in the 3100-2400 cm -1 region attributed to νNH and νOH vibrations. The broad absorption in the 1500-600 cm -1 region is attributed to the O sbnd H·O hydrogen bonds. The 1H and 13C NMR spectra have been analyzed to elucidate the structure of the P3C·SAL complex in solution. The GIAO magnetic isotropic shielding tensors have been used to predict the 1H and 13C chemical shifts in DMSO solution.

  15. Modification of electrospun polyacrylonitrile nanofibers with EDTA for the removal of Cd and Cr ions from water effluents

    NASA Astrophysics Data System (ADS)

    Chaúque, Eutilério F. C.; Dlamini, Langelihle N.; Adelodun, Adedeji A.; Greyling, Corinne J.; Catherine Ngila, J.

    2016-04-01

    Polyacrylonitrile (PAN) nanofibers were obtained by electrospinning technique prior to surface modification with polyethylenediaminetetraacetic acid (EDTA) using ethylenediamine (EDA) as the cross-linker. The modified nanofibers (EDTA-EDA-PAN) were subsequently applied in the wastewater treatment for the removal of Cd(II) and Cr(VI). Textural and chemical characterizations of the nanofibers were carried out by analysis of the specific surface area (Brauner Emmet and Teller (BET)) and thermogravimetric analyses, scanning electron microscopy and Fourier transform infrared spectroscopy. From the adsorption equilibrium studies with Langmuir, Freundlich and Temkin isotherm models, Freundlich was found most suitable for describing the removal mechanism of the target metals as they collect on a heterogeneously functionalized polymer surface. The EDTA-EDA-PAN nanofibers showed effective sorption affinity for both Cd(II) and Cr(VI), achieving maximum adsorption capacities of 32.68 and 66.24 mg g-1, respectively, at 298 K. In furtherance, the nanofibers were regenerated by simple washing with 2 M HCl solution. Conclusively, the EDTA-EDA-PAN nanofibers were found to be efficient for the removal of Cd(II) and Cr(VI) in water effluents.

  16. Superiority of zinc complex of acetylsalicylic acid to acetylsalicylic acid in preventing postischemic myocardial dysfunction.

    PubMed

    Korkmaz, Sevil; Atmanli, Ayhan; Li, Shiliang; Radovits, Tamás; Hegedűs, Peter; Barnucz, Enikő; Hirschberg, Kristóf; Loganathan, Sivakkanan; Yoshikawa, Yutaka; Yasui, Hiroyuki; Karck, Matthias; Szabó, Gábor

    2015-09-01

    The pathophysiology of ischemic myocardial injury involves cellular events, reactive oxygen species, and an inflammatory reaction cascade. The zinc complex of acetylsalicylic acid (Zn(ASA)2) has been found to possess higher anti-inflammatory and lower ulcerogenic activities than acetylsalicylic acid (ASA). Herein, we studied the effects of both ASA and Zn(ASA)2 against acute myocardial ischemia. Rats were pretreated with ASA (75 mg/kg) or Zn(ASA)2 (100 mg/kg) orally for five consecutive days. Isoproterenol (85 mg/kg, subcutaneously [s.c.]) was applied to produce myocardial infarction. After 17-22 h, animals were anesthetized with sodium pentobarbital (60 mg/kg, intraperitoneally [i.p.]) and both electrical and mechanical parameters of cardiac function were evaluated in vivo. Myocardial histological and gene expression analyses were performed. In isoproterenol-treated rats, Zn(ASA)2 treatment normalized significantly impaired left-ventricular contractility index (Emax 2.6 ± 0.7 mmHg/µL vs. 4.6 ± 0.5 mmHg/µL, P < 0.05), increased stroke volume (30 ± 3 µL vs. 50 ± 6 µL, P < 0.05), decreased systemic vascular resistance (7.2 ± 0.7 mmHg/min/mL vs. 4.2 ± 0.5 mmHg/min/mL, P < 0.05) and reduced inflammatory infiltrate into the myocardial tissues. ECG revealed a restoration of elevated ST-segment (0.21 ± 0.03 mV vs. 0.09 ± 0.02 mV, P < 0.05) and prolonged QT-interval (79.2 ± 3.2 ms vs. 69.5 ± 2.5 ms, P < 0.05) by Zn(ASA)2. ASA treatment did not result in an improvement of these parameters. Additionally, Zn(ASA)2 significantly increased the mRNA-expression of superoxide dismutase 1 (+73 ± 15%), glutathione peroxidase 4 (+44 ± 12%), and transforming growth factor (TGF)-β1 (+102 ± 22%). In conclusion, our data demonstrate that oral administration of zinc and ASA in the form of bis(aspirinato)zinc(II) complex is superior to ASA in preventing electrical

  17. Superiority of zinc complex of acetylsalicylic acid to acetylsalicylic acid in preventing postischemic myocardial dysfunction

    PubMed Central

    Korkmaz, Sevil; Atmanli, Ayhan; Li, Shiliang; Radovits, Tamás; Hegedűs, Peter; Hirschberg, Kristóf; Loganathan, Sivakkanan; Yoshikawa, Yutaka; Yasui, Hiroyuki; Karck, Matthias; Szabó, Gábor

    2015-01-01

    The pathophysiology of ischemic myocardial injury involves cellular events, reactive oxygen species, and an inflammatory reaction cascade. The zinc complex of acetylsalicylic acid (Zn(ASA)2) has been found to possess higher anti-inflammatory and lower ulcerogenic activities than acetylsalicylic acid (ASA). Herein, we studied the effects of both ASA and Zn(ASA)2 against acute myocardial ischemia. Rats were pretreated with ASA (75 mg/kg) or Zn(ASA)2 (100 mg/kg) orally for five consecutive days. Isoproterenol (85 mg/kg, subcutaneously [s.c.]) was applied to produce myocardial infarction. After 17–22 h, animals were anesthetized with sodium pentobarbital (60 mg/kg, intraperitoneally [i.p.]) and both electrical and mechanical parameters of cardiac function were evaluated in vivo. Myocardial histological and gene expression analyses were performed. In isoproterenol-treated rats, Zn(ASA)2 treatment normalized significantly impaired left-ventricular contractility index (Emax 2.6 ± 0.7 mmHg/µL vs. 4.6 ± 0.5 mmHg/µL, P < 0.05), increased stroke volume (30 ± 3 µL vs. 50 ± 6 µL, P < 0.05), decreased systemic vascular resistance (7.2 ± 0.7 mmHg/min/mL vs. 4.2 ± 0.5 mmHg/min/mL, P < 0.05) and reduced inflammatory infiltrate into the myocardial tissues. ECG revealed a restoration of elevated ST-segment (0.21 ± 0.03 mV vs. 0.09 ± 0.02 mV, P < 0.05) and prolonged QT-interval (79.2 ± 3.2 ms vs. 69.5 ± 2.5 ms, P < 0.05) by Zn(ASA)2. ASA treatment did not result in an improvement of these parameters. Additionally, Zn(ASA)2 significantly increased the mRNA-expression of superoxide dismutase 1 (+73 ± 15%), glutathione peroxidase 4 (+44 ± 12%), and transforming growth factor (TGF)-β1 (+102 ± 22%). In conclusion, our data demonstrate that oral administration of zinc and ASA in the form of bis(aspirinato)zinc(II) complex is superior to ASA in preventing electrical

  18. Spectroscopic studies on gallic acid and its azo derivatives and their iron(III) complexes.

    PubMed

    Masoud, Mamdouh S; Ali, Alaa E; Haggag, Sawsan S; Nasr, Nessma M

    2014-01-01

    Azo gallic derivatives and their iron(III) complexes were synthesized and characterized. The stereochemistry and the mode of bonding of the complexes were achieved based on elemental analysis, UV-Vis and IR. The thermal behaviors of the complexes were studied. The effect of pH on the electronic absorption spectra of gallic acid and its azo derivatives are discussed. Different spectroscopic methods (molar ratio, straight line method, continuous variation, slope ratio and successive method) are applied for determination of stoichiometry and pK values for the complex formation of gallic acid with iron(III) in aqueous media. Iron(III) complexes of gallic acid is formed with different ratio: 1:1, 1:2, 1:3 and 1:4 (M:L).

  19. Fe(II)EDTA-NO reduction coupled with Fe(II)EDTA oxidation by a nitrate- and Fe(III)-reducing bacterium.

    PubMed

    Dong, Xiyang; Zhang, Yu; Zhou, Jiti; Chen, Mingxiang; Wang, Xiaojun; Shi, Zhuang

    2013-06-01

    The nitrate- and Fe(III)-reducing bacterium Paracoccus versutus LYM was characterized in terms of its ability to perform Fe(II)EDTA-NO reduction coupled with Fe(II)EDTA oxidation (NO-dependent Fe(II)EDTA oxidation, NDFO). It experienced a single anaerobic FeEDTA redox cycling through NDFO and dissimilatory Fe(III)EDTA reduction in FeEDTA culture. The increase in the Fe(II)EDTA concentration contributed to the ascending Fe(II)EDTA-NO reduction rate. The amount of glucose controlled the rate and extent of Fe(II) oxidation during NDFO. Without glucose addition, Fe(II)EDTA-NO reduction rate was at a rather slow rate even in presence of relatively sufficient Fe(II)EDTA. Unlike aqueous Fe(2+) and solid-phase Fe(II), Fe(II)EDTA could prevent cells from encrustations. These findings suggested the occurrence of NDFO preferred being beneficial via a mixotrophic physiology in the presence of an organic cosubstrate to being out of consideration for metabolic strategy.

  20. The properties of solid Zn(II)-amino acid complexes in the form of suspensions.

    PubMed

    Dolińska, B

    2001-10-01

    An investigation was made into the experimental conditions for the formation of poorly soluble complexes of the divalent Zinc(II) combined with the following selected amino acids: tyrosine, tryptophan, cysteine, histidine, and alanine, in the form of suspensions for parenteral administration. The number of Zn(II)-binding sites in the amino acid (n) as well as the amino acid affinity to Zn(II) (Ka), were determined. Cysteine was found to have the highest number of Zn(II)-binding sites--3, whereas alanine the lowest--1. In the conditions described herein, Zn(II) amino acid complexes of diverse stability (durability) were obtained. The analysis of the kinetics of the binding revealed that the most stable complexes were those formed by Zn(II) in combination with tryptophan (Ka = 405.78 microM(-1) +/- 12.17), and with tyrosine (Ka = 343.88 microM +/- 22.35); whereas the least stable complexes were those formed by Zn(II) in combination with histidine (Ka = 29.90 microM +/- 4.78), and with alanine (Ka = 13.0 microM(-1) +/- 1.04). Cysteine formed complexes of intermediate stability (Ka = 168.53 microM(-1) +/- 12.36). The stability ofthe Zn(II) amino acid complexes obtained was conditioned by both the molecular weight (P = 0.033) of the amino acid and its isoelectric point (P < 0.001). PMID:11718265

  1. 1H NMR studies of reactions of copper complexes with human blood plasma and urine.

    PubMed

    Bligh, S W; Boyle, H A; McEwen, A B; Sadler, P J; Woodham, R H

    1992-01-22

    Reactions of the copper complexes Cu(II)Cl2, [Cu(II)(EDTA)]2-, [Cu(II)2(DIPS)4] and [Cu(I)(DMP)2]+ (where DIPS is 3,5-diisopropylsalicylate and DMP is 2,9-dimethylphenanthroline) with human blood plasma and urine have been studied by 500 MHz 1H NMR spectroscopy, and CD spectroscopy has been used to monitor the transfer of Cu(II) onto albumin in plasma. The rate of transfer of Cu(II) from [Cu(II)(EDTA)]2- onto albumin as measured by CD (T1/2 26 min, 0.5 mM Cu, 21 degrees), was similar to the rate of Cu(II) binding to amino acids and citrate, and to the rate of formation of [Ca(II)(EDTA)]2- in plasma. Reactions of Cu(II)Cl2 and [Cu(II)2(DIPS)4] in plasma followed a similar course, but were more rapid. The latter complex also appeared to give rise to the displacement of lactate from protein binding. Reactions of copper complexes in plasma therefore involve a range of low Mr ligands as well as albumin, and the ligands play a major role in determining the kinetics of the reactions. These factors, as well as the partitioning of both complexes and displaced ligands into lipoproteins, are likely to play important roles in the molecular pharmacology of copper-containing drugs. In urine, His and formate were involved in EDTA and DIPS displacement from their respective copper complexes, and peaks for free DIPS and [Ca(II)(EDTA)]2- were observed. The complex (Cu(I)(DMP)2]+ appeared to be relatively stable in both plasma and urine. PMID:1739401

  2. Stable association complex electrospray mass spectrometry for the determination of cyanuric acid.

    PubMed

    Magnuson, M L; Kelty, C A; Cantú, R

    2001-10-01

    Cyanuric acid, a suspected gastrointestinal or liver toxicant, has gained interest as a potential degradation product of triazine herbicides, such as simazine and atrazine. This paper investigates the determination of cyanuric acid by stable association complex electrospray mass spectrometry (cESI-MS). The cyanuric acid is extracted from the water through a microscale liquid-liquid extraction. The extract is evaporated to dryness, and an aqueous solution of quaternary ammonium cationic surfactant is added. When injected into the electrospray mass spectrometer, the surfactant and the cyanuric acid form a mass-selective stable association complex, which may be used for confident quantification of cyanuric acid. Several extraction solvents and surfactants were investigated. These studies provide insight into the mechanism of electrospray for the formation of these complexes, specifically with regard to the surface activity of the different surfactants and the chemistry of the surfactant-cyanuric acid complexes. From an analytical standpoint, the cESI-MS method detection limit for extraction of a 1 mL aqueous solution of cyanuric acid was 130 microg/L based on 3.14sigma(n-1) of seven replicate injections. Standard additions were used for quantification of eight aqueous samples. The cyanuric acid concentrations determined with cESI-MS were not significantly different at the 95% confidence level to those determined by conventional high-performance liquid chromatography (HPLC). A recovery of 100% from a fortified urine sample illustrates the robustness of the technique.

  3. The effect of biogenic Fe(II) on the stability and sorption of Co(II)EDTA 2- to goethite and a subsurface sediment

    NASA Astrophysics Data System (ADS)

    Zachara, John M.; Smith, Steven C.; Fredrickson, James K.

    2000-04-01

    Laboratory experiments were conducted with suspensions of goethite (α-FeOOH) and a subsurface sediment to assess the influence of bacterial iron reduction on the fate of Co(II)EDTA 2-, a representative metal-ligand complex of intermediate stability (log K Co(II)EDTA = 17.97). The goethite was synthetic (ca. 55 m 2/g) and the sediment was a Pleistocene age, Fe(III) oxide-containing material from the Atlantic coastal plain (Milford). Shewanella alga strain BrY, a dissimilatory iron reducing bacterium (DIRB), was used to promote Fe(III) oxide reduction. Sorption isotherms and pH adsorption edges were measured for Co 2+, Fe 2+, Co(II)EDTA 2-, and Fe(II)EDTA 2- on the two sorbents in 0.001 mol/L Ca(ClO 4) 2 to aid in experiment interpretation. Anoxic suspensions of the sorbents in PIPES buffer at pH 6.5-7.0 were spiked with Co(II)EDTA 2- (10 -5 mol/L, 60Co and 14EDTA labeled), inoculated with BrY (1-6 × 10 8 organisms/mL), and the headspace filled with a N 2/H 2 gas mix. The experiments were conducted under non-growth conditions. The medium did not contain PO 43- (with one exception), trace elements, or vitamins. The tubes were incubated under anoxic conditions at 25°C for time periods in excess of 100 d. Replicate tubes were sacrificed and analyzed at desired time periods for pH, Fe(II) TOT, Fe (aq)2+, 60Co, and 14EDTA. Abiotic analogue experiments were conducted where Fe (aq)2+ was added in increasing concentration to Co(II)EDTA 2-/mineral suspensions to simulate the influence of bacterial Fe(II) evolution. The DIRB generated Fe(II) from both goethite and the Milford sediment that was strongly sorbed by mineral surfaces. Aqueous Fe 2+ increased during the experiment as surfaces became saturated; Fe (aq)2+ induced the dissociation of Co(II)EDTA 2- into a mixture of Co 2+, Co(II)EDTA 2-, and Fe(II)EDTA 2- (log K Fe(II)EDTA = 15.98). The extent of dissociation of Co(II)EDTA 2- was greater in the subsurface sediment because it sorbed Fe(II) less strongly than did

  4. Complexation of di-amides of dipicolinic acid with neodymium

    SciTech Connect

    Lapka, J.L.; Paulenova, A.

    2013-07-01

    Di-amides have undergone significant studies as possible ligands for use in the partitioning of trivalent minor actinides and lanthanides. The binding affinities of three isomeric ligands with neodymium in acetonitrile solution have been investigated. The stability constants of the metal-ligand complexes formed between different isomers of N,N'-diethyl-N,N'- ditolyl-di-picolinamide (EtTDPA) and trivalent neodymium in acetonitrile have been determined by spectrophotometric and calorimetric methods. Each isomer of EtTDPA has been found to be capable of forming three complexes with trivalent neodymium, Nd(EtTDPA), Nd(EtTDPA){sub 2}, and Nd(EtTDPA){sub 3}. Values from spectrophotometric and calorimetric titrations are within reasonable agreement with each other. The order of stability constants for each metal:ligand complex decreases in the order Et(m)TDPA > Et(p)TDPA > Et(o)TDPA. The obtained values are comparable to other di-amidic ligands obtained under similar system conditions and mirror previously obtained solvent extraction data for EtTDPA at low ionic strengths. (authors.

  5. Metal complexes of salicylhydroxamic acid (H2Sha), anthranilic hydroxamic acid and benzohydroxamic acid. Crystal and molecular structure of [Cu(phen)2(Cl)]Cl x H2Sha, a model for a peroxidase-inhibitor complex.

    PubMed

    O'Brien, E C; Farkas, E; Gil, M J; Fitzgerald, D; Castineras, A; Nolan, K B

    2000-04-01

    Stability constants of iron(III), copper(II), nickel(II) and zinc(II) complexes of salicylhydroxamic acid (H2Sha), anthranilic hydroxamic acid (HAha) and benzohydroxamic acid (HBha) have been determined at 25.0 degrees C, I=0.2 mol dm(-3) KCl in aqueous solution. The complex stability order, iron(III) > copper(II) > nickel(II) approximately = zinc(II) was observed whilst complexes of H2Sha were found to be more stable than those of the other two ligands. In the preparation of ternary metal ion complexes of these ligands and 1,10-phenanthroline (phen) the crystalline complex [Cu(phen)2(Cl)]Cl x H2Sha was obtained and its crystal structure determined. This complex is a model for hydroxamate-peroxidase inhibitor interactions.

  6. Kinetic study of the complexation of gallic acid with Fe(II)

    NASA Astrophysics Data System (ADS)

    Lu, Li-li; Li, Ying-hua; Lu, Xiu-yang

    2009-10-01

    Kinetic study on the complexation of gallic acid with ferrous sulfate was performed using UV-Vis absorption spectroscopy. Under the experimental conditions, the stoichiometric composition of the formed complex is 1:1. The complexation reaction was found to be a second-order one. The influences of temperature, ionic strength and solvents on the complexation reaction were investigated. According to the Arrhenius equation, the apparent activation energy of the complexation reaction was evaluated to be 71.64 kJ × mol -1. A three-step reaction mechanism was proposed, which can well explain the kinetic results obtained.

  7. Crystallization of bFGF-DNA Aptamer Complexes Using a Sparse Matrix Designed for Protein-Nucleic Acid Complexes

    NASA Technical Reports Server (NTRS)

    Cannone, Jaime J.; Barnes, Cindy L.; Achari, Aniruddha; Kundrot, Craig E.; Whitaker, Ann F. (Technical Monitor)

    2001-01-01

    The Sparse Matrix approach for obtaining lead crystallization conditions has proven to be very fruitful for the crystallization of proteins and nucleic acids. Here we report a Sparse Matrix developed specifically for the crystallization of protein-DNA complexes. This method is rapid and economical, typically requiring 2.5 mg of complex to test 48 conditions. The method was originally developed to crystallize basic fibroblast growth factor (bFGF) complexed with DNA sequences identified through in vitro selection, or SELEX, methods. Two DNA aptamers that bind with approximately nanomolar affinity and inhibit the angiogenic properties of bFGF were selected for co-crystallization. The Sparse Matrix produced lead crystallization conditions for both bFGF-DNA complexes.

  8. Horseradish peroxidase. Complex formation with anions and hydrocyanic acid.

    PubMed

    Araiso, T; Dunford, H B

    1981-10-10

    Equilibrium binding experiments have been performed with perchlorate, chloride, and acetate in the presence of horseradish peroxidase. The binding of perchlorate and acetate appears to be like that of nitrate, at a site other than the sixth coordination position of the heme iron. Competitive experiments using both nitrate and cyanide demonstrate that two different binding sites are present on the enzyme. Chloride appears to bind at the sixth coordination position as do both fluoride and cyanide. Temperature jump experiments indicate that it is likely the nitrate anion and not undissociated nitric acid which is the binding species. Competitive stopped flow experiments indicate that the bound nitrate slows both the association rate and dissociation rate of cyanide, indicating that nitrate binds close to the sixth coordination position.

  9. Spectra, energy levels, and energy transition of lanthanide complexes with cinnamic acid and its derivatives

    NASA Astrophysics Data System (ADS)

    Zhou, Kaining; Feng, Zhongshan; Shen, Jun; Wu, Bing; Luo, Xiaobing; Jiang, Sha; Li, Li; Zhou, Xianju

    2016-04-01

    High resolution spectra and luminescent lifetimes of 6 europium(III)-cinnamic acid complex {[Eu2L6(DMF)(H2O)]·nDMF·H2O}m (L = cinnamic acid I, 4-methyl-cinnamic acid II, 4-chloro-cinnamic acid III, 4-methoxy-cinnamic acid IV, 4-hydroxy-cinnamic acid V, 4-nitro-cinnamic acid VI; DMF = N, N-dimethylformamide, C3H7NO) were recorded from 8 K to room temperature. The energy levels of Eu3 + in these 6 complexes are obtained from the spectra analysis. It is found that the energy levels of the central Eu3 + ions are influenced by the nephelauxetic effect, while the triplet state of ligand is lowered by the p-π conjugation effect of the para-substituted functional groups. The best energy matching between the ligand triplet state and the central ion excited state is found in complex I. While the other complexes show poorer matching because the gap of 5D0 and triplet state contracts.

  10. Spectra, energy levels, and energy transition of lanthanide complexes with cinnamic acid and its derivatives.

    PubMed

    Zhou, Kaining; Feng, Zhongshan; Shen, Jun; Wu, Bing; Luo, Xiaobing; Jiang, Sha; Li, Li; Zhou, Xianju

    2016-04-01

    High resolution spectra and luminescent lifetimes of 6 europium(III)-cinnamic acid complex {[Eu2L6(DMF)(H2O)]·nDMF·H2O}m (L=cinnamic acid I, 4-methyl-cinnamic acid II, 4-chloro-cinnamic acid III, 4-methoxy-cinnamic acid IV, 4-hydroxy-cinnamic acid V, 4-nitro-cinnamic acid VI; DMF=N, N-dimethylformamide, C3H7NO) were recorded from 8 K to room temperature. The energy levels of Eu(3+) in these 6 complexes are obtained from the spectra analysis. It is found that the energy levels of the central Eu(3+) ions are influenced by the nephelauxetic effect, while the triplet state of ligand is lowered by the p-π conjugation effect of the para-substituted functional groups. The best energy matching between the ligand triplet state and the central ion excited state is found in complex I. While the other complexes show poorer matching because the gap of (5)D0 and triplet state contracts.

  11. Spectra, energy levels, and energy transition of lanthanide complexes with cinnamic acid and its derivatives.

    PubMed

    Zhou, Kaining; Feng, Zhongshan; Shen, Jun; Wu, Bing; Luo, Xiaobing; Jiang, Sha; Li, Li; Zhou, Xianju

    2016-04-01

    High resolution spectra and luminescent lifetimes of 6 europium(III)-cinnamic acid complex {[Eu2L6(DMF)(H2O)]·nDMF·H2O}m (L=cinnamic acid I, 4-methyl-cinnamic acid II, 4-chloro-cinnamic acid III, 4-methoxy-cinnamic acid IV, 4-hydroxy-cinnamic acid V, 4-nitro-cinnamic acid VI; DMF=N, N-dimethylformamide, C3H7NO) were recorded from 8 K to room temperature. The energy levels of Eu(3+) in these 6 complexes are obtained from the spectra analysis. It is found that the energy levels of the central Eu(3+) ions are influenced by the nephelauxetic effect, while the triplet state of ligand is lowered by the p-π conjugation effect of the para-substituted functional groups. The best energy matching between the ligand triplet state and the central ion excited state is found in complex I. While the other complexes show poorer matching because the gap of (5)D0 and triplet state contracts. PMID:26802538

  12. Zinc complexes as fluorescent chemosensors for nucleic acids: new perspectives for a "boring" element.

    PubMed

    Terenzi, Alessio; Lauria, Antonino; Almerico, Anna Maria; Barone, Giampaolo

    2015-02-28

    Zinc(II) complexes are effective and selective nucleic acid-binders and strongly fluorescent molecules in the low energy range, from the visible to the near infrared. These two properties have often been exploited to quantitatively detect nucleic acids in biological samples, in both in vitro and in vivo models. In particular, the fluorescent emission of several zinc(II) complexes is drastically enhanced or quenched by the binding to nucleic acids and/or upon visible light exposure, in a different fashion in bulk solution and when bound to DNA. The twofold objective of this perspective is (1) to review recent utilisations of zinc(II) complexes as selective fluorescent probes for nucleic acids and (2) to highlight their novel potential applications as diagnostic tools based on their photophysical properties.

  13. Advanced oxidation processes coupled with electrocoagulation for the exhaustive abatement of Cr-EDTA.

    PubMed

    Durante, Christian; Cuscov, Marco; Isse, Abdirisak Ahmed; Sandonà, Giancarlo; Gennaro, Armando

    2011-02-01

    Using Cr-EDTA as a model system, a two-step method has been investigated for the abatement of persistent chromium complexes in water. The treatment consists of an oxidative decomposition of the organic ligands by means of ozonization or electrochemical oxidation at a boron doped diamond (BDD) electrode, followed by removal of the metal via electrochemical coagulation. In the designed synthetic waste, EDTA has been used both as a chelating agent and as a mimic of the organic content of a typical wastewater provided by a purification leather plant. A crucial point evaluated is the influence of the oxidative pretreatment on the chemical modification of the synthetic waste and hence on the electrocoagulation efficacy. Because of the great stability of Cr complexes, such as Cr-EDTA, the classical coagulation methods, based on ligand exchange between Cr(III) and Fe(II) or Fe(III), are ineffective toward Cr abatement in the presence of organic substances. On the contrary, when advanced oxidation processes (AOPs), such as ozonization or electrooxidation at a BDD anode are applied in series with electrocoagulation (EC), complete abatement of the recalcitrant Cr fraction can be achieved. ECs have been carried out by using Fe sacrificial anodes, with alternating polarization and complete Cr abatement (over 99%) has been obtained with modest charge consumption. It has been found that Cr(III) is first oxidized to Cr(VI) in the AOP preceding EC. Then, during EC, Cr(VI) is mainly reduced back to Cr(III) by electrogenerated Fe(II). Thus, Cr is mainly eliminated as Cr(III). However, a small fraction of Cr(VI) goes with the precipitate as confirmed by XPS analysis of the sludge. PMID:21255817

  14. EDTA enhances high-throughput two-dimensional bioprinting by inhibiting salt scaling and cell aggregation at the nozzle surface.

    PubMed

    Parzel, Cheryl A; Pepper, Matthew E; Burg, Timothy; Groff, Richard E; Burg, Karen J L

    2009-06-01

    Tissue-engineering strategies may be employed in the development of in vitro breast tissue models for use in testing regimens of drug therapies and vaccines. The physical and chemical interactions that occur among cells and extracellular matrix components can also be elucidated with these models to gain an understanding of the progression of transformed epithelial cells into tumours and the ultimate metastases of tumour cells. The modified inkjet printer may be a useful tool for creating three-dimensional (3D) in vitro models, because it offers an inexpensive and high-throughput solution to microfabrication, and because the printer can be easily manipulated to produce varying tissue attributes. We hypothesized, however, that when ink is replaced with a biologically based fluid (i.e. a 'bio-ink'), specifically a serum-free cell culture medium, printer nozzle failure can result from salt scale build-up as fluid evaporates on the printhead surface. In this study, ethylene diamine tetra-acetic acid (EDTA) was used as a culture medium additive to prevent salt scaling and cell aggregation during the bioprinting process. The results showed that EDTA, at a concentration typically found in commercially available trypsin solutions (0.53 mM), prevented nozzle failure when a serum-free culture medium was printed from a nozzle at 1000 drops/s. Furthermore, increasing concentrations of EDTA appeared to mildly decrease aggregation of 4T07 cells. Cell viability studies were performed to demonstrate that addition of EDTA did not result in significant cell death. In conclusion, it is recommended that EDTA be incorporated into bio-ink solutions containing salts that could lead to nozzle failure.

  15. Acetic acid-water complex: The first observation of structures containing the higher-energy acetic acid conformer

    NASA Astrophysics Data System (ADS)

    Lopes, Susy; Fausto, Rui; Khriachtchev, Leonid

    2016-02-01

    Non-covalent interaction of acetic acid (AA) and water is studied experimentally by IR spectroscopy in a nitrogen matrix and theoretically at the MP2 and coupled-cluster with single and double and perturbative triple excitations [CCSD(T)]/6-311++G(2d,2p) levels of theory. This work is focused on the first preparation and characterization of complexes of higher-energy (cis) conformer of AA with water. The calculations show three 1:1 structures for the trans-AA⋯H2O complexes and three 1:1 structures for the cis-AA⋯H2O complexes. Two trans-AA⋯H2O and two cis-AA⋯H2O complexes are found and structurally assigned in the experiments. The two cis-AA⋯ ṡ H2O complexes are obtained by annealing of a matrix containing water and cis-AA molecules prepared by selective vibrational excitation of the ground-state trans form. The less stable trans-AA⋯H2O complex is obtained by vibrational excitation of the less stable cis-AA⋯H2O complex. In addition, the 1:2 complexes of trans-AA and cis-AA with water molecules are studied computationally and the most stable forms of the 1:2 complexes are experimentally identified.

  16. Refinement of Generalized Born Implicit Solvation Parameters for Nucleic Acids and Their Complexes with Proteins.

    PubMed

    Nguyen, Hai; Pérez, Alberto; Bermeo, Sherry; Simmerling, Carlos

    2015-08-11

    The Generalized Born (GB) implicit solvent model has undergone significant improvements in accuracy for modeling of proteins and small molecules. However, GB still remains a less widely explored option for nucleic acid simulations, in part because fast GB models are often unable to maintain stable nucleic acid structures or they introduce structural bias in proteins, leading to difficulty in application of GB models in simulations of protein-nucleic acid complexes. Recently, GB-neck2 was developed to improve the behavior of protein simulations. In an effort to create a more accurate model for nucleic acids, a similar procedure to the development of GB-neck2 is described here for nucleic acids. The resulting parameter set significantly reduces absolute and relative energy error relative to Poisson-Boltzmann for both nucleic acids and nucleic acid-protein complexes, when compared to its predecessor GB-neck model. This improvement in solvation energy calculation translates to increased structural stability for simulations of DNA and RNA duplexes, quadruplexes, and protein-nucleic acid complexes. The GB-neck2 model also enables successful folding of small DNA and RNA hairpins to near native structures as determined from comparison with experiment. The functional form and all required parameters are provided here and also implemented in the AMBER software.

  17. Synthesis, spectral studies and biological evaluation of 2-aminonicotinic acid metal complexes

    NASA Astrophysics Data System (ADS)

    Nawaz, Muhammad; Abbasi, Muhammad Waseem; Hisaindee, Soleiman; Zaki, Muhammad Javed; Abbas, Hira Fatima; Mengting, Hu; Ahmed, M. Arif

    2016-05-01

    We synthesized 2-aminonicotinic acid (2-ANA) complexes with metals such as Co(II), Fe(III), Ni(II), Mn(II), Zn(II), Ag(I),Cr(III), Cd(II) and Cu(II) in aqueous media. The complexes were characterized and elucidated using FT-IR, UV-Vis, a fluorescence spectrophotometer and thermo gravimetric analysis (TGA). TGA data showed that the stoichiometry of complexes was 1:2 metal/ligand except for Ag(I) and Mn(II) where the ratio was 1:1. The metal complexes showed varied antibacterial, fungicidal and nematicidal activities. The silver and zinc complexes showed highest activity against Bacillus subtilis and Bacillus licheniformis respectively. Fusarium oxysporum was highly susceptible to nickel and copper complexes whereas Macrophomina phaseolina was completely inert to the complexes. The silver and cadmium complexes were effective against the root-knot nematode Meloidogyne javanica.

  18. Can EDTA Change MRSA into MSSA? A Future Prospective!

    PubMed Central

    Jain, Sonia; Sarkar, Soma; Ghosh, Sougata; (Mitra), Anita Nandi; Sinha, Anuradha; Chakravorty, Sriparna

    2016-01-01

    Introduction In the present era we are left behind with limited options for the treatment of serious infections caused by multidrug resistant S.aureus, most remarkably nosocomially acquired Methicillin resistant S.aureus (MRSA). The problem increases more when these strains easily become multidrug resistant (MDR) due to biofilm formation. Those staphylococcal species that are vancomycin and linezolid resistant are also resistant to other antistaphylococcal agents which call for an urgent intervention to develop newer antimicrobial agents. Aim The present study was undertaken with the aim to evaluate the antibiofilm effect of EDTA against the biofilm forming MRSA isolates, isolated from different clinical infections. Materials and Methods The biofilms formed on polystyrene microtitre plates by the MRSA strains were treated by different concentrations of EDTA to find out its anti-biofilm activity. Further simultaneously the antibiotic susceptibility pattern was noted down to check whether the MRSA strains become MSSA (Methicillin sensitive S.aureus). Results Our data demonstrates that EDTA at 4mM concentration inhibits biofilm of MRSA and at 20 mM have an ability to reduce and dissociate the biofilm membrane, allowing the antibiotics to enter and convert MRSA strains into MSSA. Conclusion These findings suggest that commercially available EDTA could be used in future to control MRSA and its biofilm- related infections. PMID:27042464

  19. Self-assembled β-lactoglobulin-oleic acid and β-lactoglobulin-linoleic acid complexes with antitumor activities.

    PubMed

    Fang, B; Zhang, M; Tian, M; Ren, F Z

    2015-05-01

    β-Lactoglobulin (β-LG) can bind to fatty acids such as oleic acid (OA) and linoleic acid (LA). Another whey protein, α-lactalbumin (α-LA), can also bind to OA to give the complex α-LA-OA, which has antitumor properties. Based on reports that the activity of α-LA-OA is highly dependent on OA, as well as the acquisition of similar complexes using other proteins, such as lysozyme and lactoferrin, we speculated whether β-LG could also kill tumor cells after binding to other fatty acids. Therefore, we prepared complexes of β-LG with OA (β-LG-OA) and LA (β-LG-LA) in the current study and evaluated them in terms of antitumor activity and thermostability using the methylene blue method and differential scanning calorimetry, respectively. The structural features of these complexes were also evaluated using fluorescence spectroscopy and circular dichroism. The binding dynamics of OA and LA to β-LG were studied using isothermal titration calorimetry. Cell viability results revealed that β-LG-LA and β-LG-OA exhibited similar antitumor activities. Interestingly, the binding of β-LG to LA led to an increase in its thermostability, whereas its binding to OA had very little effect. The environments of the tryptophan residues in the β-LG-OA and β-LG-LA complexes were very different, with the residues being blue- and red-shifted, respectively. Furthermore, the hydrophobic regions in β-LG were buried after binding of OA, which was slightly changed in β-LG-LA. Circular dichroism results showed that β-LG-OA enhanced the tertiary structure, which was partially lost in β-LG-LA. There were more binding sites for OA than for LA on β-LG, although the binding constants of the 2 fatty acids were similar, with both acids interacting with the protein though van der Waals and hydrogen bonding interactions. This study could help provide a deeper understanding of the structural basis for formation of antitumor protein-fatty acid complexes.

  20. The effect of biogenic Fe(II) on the stability and sorption of Co(II)EDTA{sup 2{minus}} to goethite and a subsurface sediment

    SciTech Connect

    Zachara, J.M.; Smith, S.C.; Fredrickson, J.K.

    2000-04-01

    Laboratory experiments were conducted with suspensions of goethite ({alpha}-FeOOH) and a subsurface sediment to assess the influence of bacterial iron reduction on the fate of Co(II)EDTA{sup 2{minus}}, a representative metal-ligand complex of intermediate stability (log K{sub Co(II)EDTA} = 17.97). The goethite was synthetic (ca. 55 m{sup 2}/g) and the sediment was a Pleistocene age, Fe(III) oxide-containing material from the Atlantic coastal plain (Milford). Shewanella alga strain BrY, a dissimulatory iron reducing bacterium (DIRB), was used to promote Fe(III) oxide reduction. Sorption isotherms and pH adsorption edges were measured for Co{sup 2+}, Fe{sup 2+}, Co(II)EDTA{sup 2{minus}}, and Fe(II)EDTA{sup 2{minus}} on the two sorbents in 0.001 mol/L Ca(ClO{sub 4}){sub 2} to aid in experiment interpretation. It is concluded that cationic radionuclides such as {sup 60}Co or {sup 239/240}Pu, which may be mobilized from disposed wastes by complexation with EDTA{sup 4{minus}}, may become immobilized in groundwater zones where dissimilatory bacterial iron reduction is operative.

  1. Heavy metal extraction from an artificially contaminated sandy soil under EDDS deficiency: significance of humic acid and chelant mixture.

    PubMed

    Yip, Theo C M; Yan, Dickson Y S; Yui, Matthew M T; Tsang, Daniel C W; Lo, Irene M C

    2010-06-01

    Biodegradable EDDS ([S,S]-ethylenediaminedisuccinic acid) has been suggested for enhancing heavy metal extraction from contaminated soils. Recent studies showed that Zn and Pb are less effectively extracted due to metal exchange and re-adsorption onto the soil surfaces, especially for EDDS-deficiency conditions. This study therefore investigated the influence of dissolved organic matter and the co-presence of EDTA (ethylene-diamine-tetraacetic acid) on metal extraction from an artificially contaminated sandy soil under deficient amount of chelants in batch kinetics experiments. The addition of 10 and 20mgL(-1) of humic acid as dissolved organic matter (DOC) suppressed metal extraction by EDDS, probably resulting from the competition of adsorbed humic acid for heavy metals and adsorption of metal-humate complexes onto the soil surfaces. The effects were most significant for Pb because of greater extent of metal exchange of PbEDDS and high affinity towards organic matter. Thus, one should be cautious when there is a high content of organic matter in soils or groundwater. On the other hand, compared to individual additions of EDDS or EDTA, the equimolar EDDS and EDTA mixture exhibited significantly higher Pb extraction without notable Pb re-adsorption. The synergistic performance of the EDDS and EDTA mixture probably resulted from the change of chemical speciation and thus less competition among Cu, Zn and Pb for each chelant. These findings suggest further investigation into an optimum chemistry of the chelant mixture taking into account the effectiveness and associated environmental impact.

  2. Evaluation of effectiveness of EDTA and sodium thiosulfate in removing metal toxicity toward sea urchin embryo-larval applying the TIE.

    PubMed

    Resgalla, C; Poleza, F; Souza, R C; Máximo, M V; Radetski, C M

    2012-09-01

    Since the development of the TIE (Toxicity Identification and Evaluation) in 1988 it has been assumed that the capacity of EDTA and sodium thiosulfate to complex some metals, and thus remove their toxicity, can be applied to both freshwater and seawater ecotoxicological tests and the results subsequently interpreted. However, it is now known that there is a wide variability in the extent of this complexation. In this context, the removal of toxicity caused by the presence of Hg(2+), Cd(2+), Cu(2+), Cr(6+), Zn(2+), Ni(2+), Pb(2+), Ag(1+) and Se(2+), through metal complexation by EDTA and sodium thiosulfate, in relation to the performance of embryo-larval tests with the sea urchin Arbacia lixula was investigated. It was observed that EDTA was capable of removing the toxicity of Pb(2+), Zn(2+) and Cu(2+) while sodium thiosulfate only reduced the toxicity of Ag(1+). Compared to the complexation observed in freshwater ecotoxicological tests, the complexing agents used in this study (EDTA and sodium thiosulfate) have a lower capacity to complex metals in the marine ecotoxicological test with A. lixula.

  3. Rapid complexing of oxoacylglycerols with amino acids, peptides and aminophospholipids.

    PubMed

    Kurvinen, J P; Kuksis, A; Ravandi, A; Sjövall, O; Kallio, H

    1999-03-01

    We prepared model Schiff bases from 2-[9-oxo]nonanoyl glycerol (2-MAG-ALD) and various amino compounds. 2-MAG-ALD was obtained by pancreatic lipase hydrolysis of trioleoyl glycerol and reductive ozonolysis of the resulting 2-monooleoyl glycerol. The reaction products were purified by thin-layer chromatography. Schiff bases were synthesized in greater than 50% yield by reacting 2-MAG-ALD with twofold molar excess of valine, Nalpha-acetyl-L-lysine methyl ester and the tripeptides glycyl-glycyl-glycine, glycyl-glycyl-histidine, and glycyl-histidyl-lysine in aqueous methanol and with 1-palmitoyl-2-stearoyl glycerophosphoethanolamine (PE) in chloroform/methanol for 16 h at room temperature. Prior to analysis the bases were reduced with sodium cyanoborohydride in methanol for 30 min at 4 degrees C. Reaction products were analyzed by high-performance liquid chromatography/electrospray ionization/mass spectrometry (HPLC/ESI/MS). Reduced Schiff bases of 2-MAG-ALD with PE and amino acids were analyzed by normal-phase HPLC/ESI/MS and those with peptides by reversed-phase HPLC/ESI/MS. Single adducts were obtained in all cases and both the alpha-amino group of valine and the epsilon-amino group of Nalpha-acetyl-L-lysine methyl ester were reactive. Molecular ions of reaction products were the only detected ions in the negative ionization mode, whereas in the positive ion mode sodiated molecular ions were also detected. The present study suggests that 2-MAG-ALD may form Schiff base adducts with amino compounds in other aqueous media, such as the intestinal lumen and in the hydrophobic environment of cell membranes. PMID:10230725

  4. Accurate ab initio prediction of NMR chemical shifts of nucleic acids and nucleic acids/protein complexes

    PubMed Central

    Victora, Andrea; Möller, Heiko M.; Exner, Thomas E.

    2014-01-01

    NMR chemical shift predictions based on empirical methods are nowadays indispensable tools during resonance assignment and 3D structure calculation of proteins. However, owing to the very limited statistical data basis, such methods are still in their infancy in the field of nucleic acids, especially when non-canonical structures and nucleic acid complexes are considered. Here, we present an ab initio approach for predicting proton chemical shifts of arbitrary nucleic acid structures based on state-of-the-art fragment-based quantum chemical calculations. We tested our prediction method on a diverse set of nucleic acid structures including double-stranded DNA, hairpins, DNA/protein complexes and chemically-modified DNA. Overall, our quantum chemical calculations yield highly/very accurate predictions with mean absolute deviations of 0.3–0.6 ppm and correlation coefficients (r2) usually above 0.9. This will allow for identifying misassignments and validating 3D structures. Furthermore, our calculations reveal that chemical shifts of protons involved in hydrogen bonding are predicted significantly less accurately. This is in part caused by insufficient inclusion of solvation effects. However, it also points toward shortcomings of current force fields used for structure determination of nucleic acids. Our quantum chemical calculations could therefore provide input for force field optimization. PMID:25404135

  5. Antidiabetic effect of the α-lipoic acid γ-cyclodextrin complex.

    PubMed

    Naito, Yuki; Ikuta, Naoko; Nakata, Daisuke; Terao, Keiji; Matsumoto, Kinuyo; Kajiwara, Naemi; Okano, Ayaka; Yasui, Hiroyuki; Yoshikawa, Yutaka

    2014-09-01

    In recent years, the number of patients suffering from diabetes mellitus has been increasing worldwide. In particular, type 2 diabetes mellitus, a lifestyle-related disease, is recognized as a serious disease with various complications. Many types of pharmaceutics or specific health foods have been used for the management of diabetes mellitus. At the same time, the relationship between diabetes mellitus and α-lipoic acid has been recognized for many years. In this study, we found that the α-lipoic acid γ-cyclodextrin complex exhibited an HbA1c lowering effect for treating type 2 diabetes mellitus in animal models. Moreover, in this study, we investigated the activation of phosphorylation of AMP-activated protein kinase, which plays a role in cellular energy homeostasis, in the liver of KKA(y) mice by using α-lipoic acid and the α-lipoic acid γ-cyclodextrin complex. Our results show that the α-lipoic acid γ-cyclodextrin complex strongly induced the phosphorylation of AMP-activated protein kinase. Thus, we concluded that intake of the α-lipoic acid γ-cyclodextrin complex exerted an antidiabetic effect by suppressing the elevation of postprandial hyperglycemia as well as doing exercise.

  6. Direct observation of unstable reaction intermediates by acid-base complex formation.

    PubMed

    Ohashi, Yuji

    2013-06-01

    The structures of several unstable or metastable reaction intermediates that were photoproduced in crystals were analyzed by using X-ray techniques. The presence of enough void space around the reactive group(s) is an essential factor for the reaction to occur with retention of the single-crystal form. To expand the void space, an acid group (COOH) was substituted onto the reactant molecule and acid-base complex crystals were prepared with several amines, such as dibenzylamine and dicyclohexylamine. Following the formation of such acid-base complexes in crystals, the metastable structures of nitrenes and red species of photochromic salicylideneanilines have been successfully analyzed by using X-ray techniques. Moreover, the structure of a Pt complex anion in the excited state has been analyzed, which formed acid-base complex crystals with various alkylammonium cations. The formation of acid-base complexes will be a powerful tool for directly observing the structure of unstable or metastable reaction intermediates by using X-ray techniques.

  7. Membrane protein complexes catalyze both 4- and 3-hydroxylation of cinnamic acid derivatives in monolignol biosynthesis.

    PubMed

    Chen, Hsi-Chuan; Li, Quanzi; Shuford, Christopher M; Liu, Jie; Muddiman, David C; Sederoff, Ronald R; Chiang, Vincent L

    2011-12-27

    The hydroxylation of 4- and 3-ring carbons of cinnamic acid derivatives during monolignol biosynthesis are key steps that determine the structure and properties of lignin. Individual enzymes have been thought to catalyze these reactions. In stem differentiating xylem (SDX) of Populus trichocarpa, two cinnamic acid 4-hydroxylases (PtrC4H1 and PtrC4H2) and a p-coumaroyl ester 3-hydroxylase (PtrC3H3) are the enzymes involved in these reactions. Here we present evidence that these hydroxylases interact, forming heterodimeric (PtrC4H1/C4H2, PtrC4H1/C3H3, and PtrC4H2/C3H3) and heterotrimeric (PtrC4H1/C4H2/C3H3) membrane protein complexes. Enzyme kinetics using yeast recombinant proteins demonstrated that the enzymatic efficiency (V(max)/k(m)) for any of the complexes is 70-6,500 times greater than that of the individual proteins. The highest increase in efficiency was found for the PtrC4H1/C4H2/C3H3-mediated p-coumaroyl ester 3-hydroxylation. Affinity purification-quantitative mass spectrometry, bimolecular fluorescence complementation, chemical cross-linking, and reciprocal coimmunoprecipitation provide further evidence for these multiprotein complexes. The activities of the recombinant and SDX plant proteins demonstrate two protein-complex-mediated 3-hydroxylation paths in monolignol biosynthesis in P. trichocarpa SDX; one converts p-coumaric acid to caffeic acid and the other converts p-coumaroyl shikimic acid to caffeoyl shikimic acid. Cinnamic acid 4-hydroxylation is also mediated by the same protein complexes. These results provide direct evidence for functional involvement of membrane protein complexes in monolignol biosynthesis.

  8. A complex of equine lysozyme and oleic acid with bactericidal activity against Streptococcus pneumoniae.

    PubMed

    Clementi, Emily A; Wilhelm, Kristina R; Schleucher, Jürgen; Morozova-Roche, Ludmilla A; Hakansson, Anders P

    2013-01-01

    HAMLET and ELOA are complexes consisting of oleic acid and two homologous, yet functionally different, proteins with cytotoxic activities against mammalian cells, with HAMLET showing higher tumor cells specificity, possibly due to the difference in propensity for oleic acid binding, as HAMLET binds 5-8 oleic acid molecules per protein molecule and ELOA binds 11-48 oleic acids. HAMLET has been shown to possess bactericidal activity against a number of bacterial species, particularly those with a respiratory tropism, with Streptococcus pneumoniae displaying the greatest degree of sensitivity. We show here that ELOA also displays bactericidal activity against pneumococci, which at lower concentrations shows mechanistic similarities to HAMLET's bactericidal activity. ELOA binds to S. pneumoniae and causes perturbations of the plasma membrane, including depolarization and subsequent rupture, and activates an influx of calcium into the cells. Selective inhibition of calcium channels and sodium/calcium exchange activity significantly diminished ELOA's bactericidal activity, similar to what we have observed with HAMLET. Finally, ELOA-induced death was also accompanied by DNA fragmentation into high molecular weight fragments - an apoptosis-like morphological phenotype that is seen during HAMLET-induced death. Thus, in contrast to different mechanisms of eukaryote cell death induced by ELOA and HAMLET, these complexes are characterized by rather similar activities towards bacteria. Although the majority of these events could be mimicked using oleic acid alone, the concentrations of oleic acid required were significantly higher than those present in the ELOA complex, and for some assays, the results were not identical between oleic acid alone and the ELOA complex. This indicates that the lipid, as a common denominator in both complexes, is an important component for the complexes' bactericidal activities, while the proteins are required both to solubilize and/or present the

  9. Characterization of radionuclide-chelating agent complexes found in low-level radioactive decontamination waste. Literature review

    SciTech Connect

    Serne, R.J.; Felmy, A.R.; Cantrell, K.J.; Krupka, K.M.; Campbell, J.A.; Bolton, H. Jr.; Fredrickson, J.K.

    1996-03-01

    The US Nuclear Regulatory Commission is responsible for regulating the safe land disposal of low-level radioactive wastes that may contain organic chelating agents. Such agents include ethylenediaminetetraacetic acid (EDTA), diethylenetriaminepentaacetic acid (DTPA), picolinic acid, oxalic acid, and citric acid, and can form radionuclide-chelate complexes that may enhance the migration of radionuclides from disposal sites. Data from the available literature indicate that chelates can leach from solidified decontamination wastes in moderate concentration (1--100 ppm) and can potentially complex certain radionuclides in the leachates. In general it appears that both EDTA and DTPA have the potential to mobilize radionuclides from waste disposal sites because such chelates can leach in moderate concentration, form strong radionuclide-chelate complexes, and can be recalcitrant to biodegradation. It also appears that oxalic acid and citric acid will not greatly enhance the mobility of radionuclides from waste disposal sites because these chelates do not appear to leach in high concentration, tend to form relatively weak radionuclide-chelate complexes, and can be readily biodegraded. In the case of picolinic acid, insufficient data are available on adsorption, complexation of key radionuclides (such as the actinides), and biodegradation to make definitive predictions, although the available data indicate that picolinic acid can chelate certain radionuclides in the leachates.

  10. Benefits of the Use of Sewage Sludge over EDTA to Remediate Soils Polluted with Heavy Metals.

    PubMed

    Hernández, Ana J; Gutiérrez-Ginés, María J; Pastor, Jesús

    2015-09-01

    Sewage sludges from urban wastewater treatment plants are often used to remediate degraded soils. However, the benefits of their use in metal-polluted soils remain unclear and need to be assessed in terms of factors besides soil fertility. This study examines the use of thermal-dried sewage sludge (TDS) as an amendment for heavy metal-polluted soil in terms of its effects on soil chemical properties, leachate composition, and the growth of native plant communities. To assess the response of the soil and its plant community to an increase in metal mobilization, the effects of TDS amendment were compared with those of the addition of a chelating agent (ethylenediaminetetraacetic acid [EDTA]). The experimental design was based on a real-case scenario in which soils from of an abandoned mine site were used in a greenhouse bioassay. Two doses of TDS and EDTA were applied to a soil containing high Pb, Zn, Cu, and Cd levels (4925, 5675, 404, and 25 mg kg, respectively). Soil pH was 6.4, and its organic matter content was 5.53%. The factors examined after soil amendment were soil fertility and heavy metal contents, leachate element losses, the plant community arising from the seed bank (plant cover, species richness and biodiversity, above/below ground biomass), and phytotoxic effects (chemical contents of abundant species). Thermal-dried sewage sludge emerged as a good phytostabilizer of Pb, Zn, Cu, and Cd given its capacity to reduce the plant uptake of metals and achieve rapid plant cover. This amendment also enhanced the retention of other elements in the plant root system and overall showed a better capacity to remediate soils polluted with several heavy metals. The addition of EDTA led to plant productivity losses and nutritional imbalances because it increased the mobility of several elements in the soil and its leachates.

  11. Benefits of the Use of Sewage Sludge over EDTA to Remediate Soils Polluted with Heavy Metals.

    PubMed

    Hernández, Ana J; Gutiérrez-Ginés, María J; Pastor, Jesús

    2015-09-01

    Sewage sludges from urban wastewater treatment plants are often used to remediate degraded soils. However, the benefits of their use in metal-polluted soils remain unclear and need to be assessed in terms of factors besides soil fertility. This study examines the use of thermal-dried sewage sludge (TDS) as an amendment for heavy metal-polluted soil in terms of its effects on soil chemical properties, leachate composition, and the growth of native plant communities. To assess the response of the soil and its plant community to an increase in metal mobilization, the effects of TDS amendment were compared with those of the addition of a chelating agent (ethylenediaminetetraacetic acid [EDTA]). The experimental design was based on a real-case scenario in which soils from of an abandoned mine site were used in a greenhouse bioassay. Two doses of TDS and EDTA were applied to a soil containing high Pb, Zn, Cu, and Cd levels (4925, 5675, 404, and 25 mg kg, respectively). Soil pH was 6.4, and its organic matter content was 5.53%. The factors examined after soil amendment were soil fertility and heavy metal contents, leachate element losses, the plant community arising from the seed bank (plant cover, species richness and biodiversity, above/below ground biomass), and phytotoxic effects (chemical contents of abundant species). Thermal-dried sewage sludge emerged as a good phytostabilizer of Pb, Zn, Cu, and Cd given its capacity to reduce the plant uptake of metals and achieve rapid plant cover. This amendment also enhanced the retention of other elements in the plant root system and overall showed a better capacity to remediate soils polluted with several heavy metals. The addition of EDTA led to plant productivity losses and nutritional imbalances because it increased the mobility of several elements in the soil and its leachates. PMID:26436275

  12. 40 CFR 180.1302 - Sodium Ferric Ethylenediaminetetraacetate (EDTA); exemption from the requirement of a tolerance.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... Ethylenediaminetetraacetate (EDTA); exemption from the requirement of a tolerance. 180.1302 Section 180.1302 Protection of... Ethylenediaminetetraacetate (EDTA); exemption from the requirement of a tolerance. An exemption from the requirement of a tolerance is established for residues of sodium ferric EDTA in or on all food commodities when applied as...

  13. 40 CFR 180.1302 - Sodium Ferric Ethylenediaminetetraacetate (EDTA); exemption from the requirement of a tolerance.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... Ethylenediaminetetraacetate (EDTA); exemption from the requirement of a tolerance. 180.1302 Section 180.1302 Protection of... Ethylenediaminetetraacetate (EDTA); exemption from the requirement of a tolerance. An exemption from the requirement of a tolerance is established for residues of sodium ferric EDTA in or on all food commodities when applied as...

  14. 40 CFR 180.1302 - Sodium Ferric Ethylenediaminetetraacetate (EDTA); exemption from the requirement of a tolerance.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... Ethylenediaminetetraacetate (EDTA); exemption from the requirement of a tolerance. 180.1302 Section 180.1302 Protection of... Ethylenediaminetetraacetate (EDTA); exemption from the requirement of a tolerance. An exemption from the requirement of a tolerance is established for residues of sodium ferric EDTA in or on all food commodities when applied as...

  15. 40 CFR 180.1302 - Sodium Ferric Ethylenediaminetetraacetate (EDTA); exemption from the requirement of a tolerance.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... Ethylenediaminetetraacetate (EDTA); exemption from the requirement of a tolerance. 180.1302 Section 180.1302 Protection of... Ethylenediaminetetraacetate (EDTA); exemption from the requirement of a tolerance. An exemption from the requirement of a tolerance is established for residues of sodium ferric EDTA in or on all food commodities when applied as...

  16. Water Soluble Usnic Acid-Polyacrylamide Complexes with Enhanced Antimicrobial Activity against Staphylococcus epidermidis

    PubMed Central

    Francolini, Iolanda; Taresco, Vincenzo; Crisante, Fernanda; Martinelli, Andrea; D’Ilario, Lucio; Piozzi, Antonella

    2013-01-01

    Usnic acid, a potent antimicrobial and anticancer agent, poorly soluble in water, was complexed to novel antimicrobial polyacrylamides by establishment of strong acidic-base interactions. Thermal and spectroscopic analysis evidenced a molecular dispersion of the drug in the polymers and a complete drug/polymer miscibility for all the tested compositions. The polymer/drug complexes promptly dissolved in water and possessed a greater antimicrobial activity against Staphylococcus epidermidis than both the free drug and the polymer alone. The best results were obtained with the complex based on the lowest molecular weight polymer and containing a low drug content. Such a complex showed a larger inhibition zone of bacterial growth and a lower minimum inhibitory concentration (MIC) with respect to usnic acid alone. This improved killing effect is presumably due to the reduced size of the complexes that allows an efficient cellular uptake of the antimicrobial complexes. The killing effect extent seems to be not significantly dependent on usnic acid content in the samples. PMID:23549269

  17. Complex formation with nucleic acids and aptamers alters the antigenic properties of platelet factor 4

    PubMed Central

    Jaax, Miriam E.; Krauel, Krystin; Marschall, Thomas; Brandt, Sven; Gansler, Julia; Fürll, Birgitt; Appel, Bettina; Fischer, Silvia; Block, Stephan; Helm, Christiane A.; Müller, Sabine; Preissner, Klaus T.

    2013-01-01

    The tight electrostatic binding of the chemokine platelet factor 4 (PF4) to polyanions induces heparin-induced thrombocytopenia, a prothrombotic adverse drug reaction caused by immunoglobulin G directed against PF4/polyanion complexes. This study demonstrates that nucleic acids, including aptamers, also bind to PF4 and enhance PF4 binding to platelets. Systematic assessment of RNA and DNA constructs, as well as 4 aptamers of different lengths and secondary structures, revealed that increasing length and double-stranded segments of nucleic acids augment complex formation with PF4, while single nucleotides or single-stranded polyA or polyC constructs do not. Aptamers were shown by circular dichroism spectroscopy to induce structural changes in PF4 that resemble those induced by heparin. Moreover, heparin-induced anti-human–PF4/heparin antibodies cross-reacted with human PF4/nucleic acid and PF4/aptamer complexes, as shown by an enzyme immunoassay and a functional platelet activation assay. Finally, administration of PF4/44mer–DNA protein C aptamer complexes in mice induced anti–PF4/aptamer antibodies, which cross-reacted with murine PF4/heparin complexes. These data indicate that the formation of anti-PF4/heparin antibodies in postoperative patients may be augmented by PF4/nucleic acid complexes. Moreover, administration of therapeutic aptamers has the potential to induce anti-PF4/polyanion antibodies and a prothrombotic diathesis. PMID:23673861

  18. Thumbnail Sketches: EDTA-Type Chelating Agents in Everyday Consumer Products: Some Medicinal and Personal Care Products.

    ERIC Educational Resources Information Center

    Hart, J. Roger

    1984-01-01

    Discusses various ethylenediaminetetraacetate (EDTA)-type chelating agents found in ophthalmic products, personal care products, and disinfectants. Also discusses the properties and action of these EDTA agents. (JN)

  19. Sustained bacterial reduction of Co{sup III}EDTA{sup {minus}} in the presence of competing geochemical oxidation during dynamic flow

    SciTech Connect

    Brooks, S.C.; Carroll, S.L.; Jardine, P.M.

    1999-09-01

    Radionuclides and metals can be mobilized by chelating agents typically present in low-level radioactive liquid wastes. [{sup 60}Co]EDTA in the form {sup 60}Co{sup III}EDTA{sup {minus}} represents a highly stable and mobile form of this radionuclide. By contract, the reduced form of this metal-ligand complex, {sup 60}Co{sup II}EDTA{sup 2{minus}}, is much less stable and less mobile. There is an increasing awareness that dissimilatory metal-reducing bacteria (DMRB) can be used to mediate redox transformations of metals and radionuclides whose stability and mobility are governed by their oxidation state. The authors conducted a series of column experiments to provide an improved understanding of Co{sup III}EDTA{sup {minus}} reduction by the facultative anaerobe Shewanella alga BrY (BrY). Experiments were conducted under growth conditions using lactate a carbon and energy source. They were able to demonstrate the sustained reduction of Co{sup III}EDTA{sup {minus}} in column flow experiments with the desired result that a less stable, less mobile product was formed. The amount of reduction varied directly with the fluid residence time in the columns. In the presence of a suitable mineral sorbent [Fe(OH){sub 3}], Co-EDTA transport was delayed as a direct consequence of the bacterial reduction reaction. Even in the presence of a strong mineral oxidant the net reduction of Co{sup III}EDTA{sup {minus}} dominated the fate and transport of this species.

  20. EXAFS and XRD studies of copper and cobalt complexes of amino acid

    NASA Astrophysics Data System (ADS)

    Mishra, A.; Yadav, A.; Ninama, S.; Trivedi, A.

    2012-05-01

    The present paper deals with the synthesis of transition metal schiff base complexes of Para amino benzoic acid (PABA) by chemical root method. The synthesized metal complexes were characterized by XRD analysis, Extended X-ray absorption fine structure (EXAFS) is a technique that has been used for determining the metal ligand bond length using conventional X-ray source and also by EXAFS analysis using IFEFFIT programming. Bond lengths determined from these data analysis methods are compared with the bond lengths obtained from LSS, Levy's and Lytle's methods. All the complexes show the crystalline simple cubic structure. Bond lengths of the complexes are in good agreement obtained by theoretical and experimental methods.

  1. Incorporation of Deoxyribonucleic Acid Precursors by T4 Deoxyribonucleic Acid-Protein Complexes Retained on Glass Fiber Filters

    PubMed Central

    Miller, Robert C.; Kozinski, Andrzej W.

    1970-01-01

    Bacteriophage T4 deoxyribonucleic acid (DNA)-protein complexes were retained preferentially on glass fiber filters. DNA polymerase activity in the complex was detected through the incorporation of 3H-labeled DNA precursors. The primer-product DNA hybridized with both phage and Escherichia coli DNA. Density labeling experiments showed that about 30% of incorporated 3H-deoxyadenosine triphosphate was found in DNA which hybridized with phage DNA; this DNA was found to be covalently attached to the primer DNA. PMID:5497903

  2. Structural and thermotropic properties of calcium-dimyristoylphosphatidic acid complexes at acidic and neutral pH conditions.

    PubMed Central

    Takahashi, H.; Yasue, T.; Ohki, K.; Hatta, I.

    1995-01-01

    Two kinds of calcium-dimyristoylphosphatidic acid (DMPA) complexes at acidic and neutral pH conditions were prepared in the following ways. The complex at pH 4 was obtained by adding Ca2+ to DMPA dispersion in pure water. On the other hand, the complex at pH 7.4 was obtained by adding Ca2+ to DMPA dispersion in the presence of NaOH. The stoichiometries of Ca2+ ion to DMPA molecule are 0.5-0.67 and approximately 1 for the complexes at pH 4 and 7.4, respectively. Static x-ray diffraction shows that the hydrocarbon chains of the Ca(2+)-DMPA complex at pH 4 at 20 degrees C are more tightly packed than those of the complex at pH 7.4 at 20 degrees C. Furthermore, the complex at pH 4 at 20 degrees C gives rise to several reflections that might be related to the ordered arrangement of the Ca2+ ions. These results indicate that the structure of the complex at pH 4 is crystalline-like. In the differential scanning calorimetry (DSC) thermogram, the complex at pH 7.4 undergoes no phase transition in a temperature range between 30 and 80 degrees C. On the other hand, in the DSC thermogram for the complex at pH 4, a peak appears at 65.8 degrees C in the first heating scan. In the successive second heating scan, a transition peak appears at 63.5 degrees C. In connection with the DSC results, the structural changes associated with these phase transitions were studied with temperature-scan x-ray diffraction. In the first heating scan, although a peak appears at 65.80C in the DSC thermogram, the hydrocarbon chain packing gradually converts from an orthorhombic lattice to a hexagonal lattice near 52 degree C, and successively the chain melting phase transition occurs near 670C. In the second heating scan, the hydrocarbon chains are packed in a hexagonal lattice over the whole temperature range and the chain melting phase transition occurs near 63.5 degree C. Therefore,the Ca2+-DMPA complex at pH 4 has a metastable state. The metastable state transforms to a stable state by

  3. Preparation and spectral investigation of inclusion complex of caffeic acid with hydroxypropyl-beta-cyclodextrin.

    PubMed

    Zhang, Min; Li, Jinxia; Zhang, Liwei; Chao, Jianbin

    2009-01-01

    The inclusion complexation behavior of caffeic acid (CA) with hydroxypropyl-beta-cyclodextrin (HP-beta-CD) was studied by UV-vis, fluorescence spectroscopy and nuclear magnetic resonance spectroscopy (NMR). Experimental conditions including the concentration of HP-beta-CD and media acidity were investigated in detail. The result suggested HP-beta-CD was more suitable for including CA in acidity solution. The binding contants (K) of the inclusion complexes were determined by linear regression analysis and the inclusion ratio was found to be 1:1. The water solubility of CA was increased by inclusion with HP-beta-CD according to the phase-solubility diagram. The spatial configuration of complex has been proposed based on (1)H NMR and two-dimensional (2D) NMR, the result suggested that CA was entrapped inside the hydrophobic core of HP-beta-CD with the lipophilic aromatic ring and the portion of ethylene.

  4. Kinetics of acid hydrolysis and reactivity of some antibacterial hydrophilic iron(II) imino-complexes

    NASA Astrophysics Data System (ADS)

    Shaker, Ali Mohamed; Nassr, Lobna Abdel-Mohsen Ebaid; Adam, Mohamed Shaker Saied; Mohamed, Ibrahim Mohamed Abdelhalim

    2015-05-01

    Kinetic study of acid hydrolysis of some hydrophilic Fe(II) Schiff base amino acid complexes with antibacterial properties was performed using spectrophotometry. The Schiff base ligands were derived from sodium 2-hydroxybenzaldehyde-5-sulfonate and glycine, L-alanine, L-leucine, L-isoleucine, DL-methionine, DL-serine, or L-phenylalanine. The reaction was studied in aqueous media under conditions of pseudo-first order kinetics. Moreover, the acid hydrolysis was studied at different temperatures and the activation parameters were calculated. The general rate equation was suggested as follows: rate = k obs [Complex], where k obs = k 2 [H+]. The evaluated rate constants and activation parameters are consistent with the hydrophilicity of the investigated complexes.

  5. The influence of different growth stages and dosage of EDTA on Cd uptake and accumulation in Cd-hyperaccumulator (Solanum nigrum L.).

    PubMed

    Sun, Yuebing; Zhou, Qixing; Wang, Lin; Liu, Weitao

    2009-03-01

    Application of synthetic chelates such as ethylene diamine tetraacetic acid (EDTA) has been proposed as an alternative technology for phytoextraction of contaminated soils. In a pot experiment, the effects of EDTA application at three growing stages on growth and Cd uptake and accumulation of Solanum nigrum L. were investigated. The results showed that the 0.1 g/kg EDTA treatment was the most effective treatment, in which the concentrations of Cd in stems and leaves increased significantly compared with the control (Cd only), and the accumulation of Cd in shoots increased by 51.6%, 61.1% and 35.9% at the seedling, flowering and mature stages, respectively. Moreover, at the flowering stage, the height, dry shoot biomass and Cd accumulation in the plants reached the maximum, which were 18.9 cm, 1.8 g/plant and 292.8 microg/pot, respectively. However, higher rate of EDTA (0.5 g/kg) could reduce the plant biomass and the total amount of Cd removed. The results indicated that moderate rate of EDTA applied at the flowering stage would be important to enhance phytoremediation efficiency in practice. PMID:19002363

  6. Multifunctional nanocomposites Fe3O4@SiO2-EDTA for Pb(II) and Cu(II) removal from aqueous solutions

    NASA Astrophysics Data System (ADS)

    Liu, Yu; Fu, Ruiqi; Sun, Yue; Zhou, Xiaoxin; Baig, Shams Ali; Xu, Xinhua

    2016-04-01

    In this study, EDTA-functionalized Fe3O4 (Fe3O4@SiO2-EDTA) was prepared by silanization reaction between N-(trimethoxysilylpropyl) ethylenediamine triacetic acid (EDTA-silane) and hydroxyl groups for Pb(II) and Cu(II) removal from aqueous solutions. Fe3O4@SiO2-EDTA composites were characterized using SEM, TEM, EDX, FTIR, XPS, TGA and saturated magnetization techniques. Maximum Pb(II) adsorption capacity was found to be 114.94 mg g-1 with SiO2/EDTA molar ratio of 2.5:1. The adsorption rate was significantly fast and the equilibrium was reached within 10 min. The optimum pH was recorded to be 5.0. The maximum adsorption capacity of the studied heavy metal ions calculated by Langmuir model followed the order: Cu(II) (0.58 mmol g-1) > Pb(II) (0.55 mmol g-1) ≈ Ni(II) (0.55 mmol g-1) > Cd(II) (0.45 mmol g-1). Moreover, Pb(II) and Cu(II) adsorption capacities were not significantly affected by co-existing cations and NOM. These results suggested that this adsorbent can be considered as a promising adsorbent to remove Pb(II) and Cu(II) from wastewaters.

  7. Communication: Physical origins of ionization potential shifts in mixed carboxylic acids and water complexes.

    PubMed

    Gu, Quanli; Tang, Zhen; Su, Peifeng; Wu, Wei; Yang, Zhijun; Trindle, Carl O; Knee, Joseph L

    2016-08-01

    The ionization potential (IP) of the aromatic alpha hydroxy carboxylic acid, 9-hydroxy-9-fluorene carboxylic acid (9HFCA), is shifted by complexation with hydrogen bonding ligands such as water and formic acid. Generalized Kohn-Sham energy decomposition analysis decomposes the intermolecular binding energies into a frozen energy term, polarization, correlation, and/or dispersion energy terms, as well as terms of geometric relaxation and zero point energy. We observe that in each dimer the attractive polarization always increases upon ionization, enhancing binding in the cation and shifting the IP toward the red. For 9HFCA-H2O, a substantial decrease of the repulsive frozen energy in cation further shifts the IP toward red. For 9HFCA-HCOOH, the increase of the frozen energy actually occurs in the cation and shifts the IP toward blue. Consistent with the experimental measurements, our analysis provides new, non-intuitive perspectives on multiple hydrogen bonds interactions in carboxylic acids and water complexes.

  8. Communication: Physical origins of ionization potential shifts in mixed carboxylic acids and water complexes

    NASA Astrophysics Data System (ADS)

    Gu, Quanli; Tang, Zhen; Su, Peifeng; Wu, Wei; Yang, Zhijun; Trindle, Carl O.; Knee, Joseph L.

    2016-08-01

    The ionization potential (IP) of the aromatic alpha hydroxy carboxylic acid, 9-hydroxy-9-fluorene carboxylic acid (9HFCA), is shifted by complexation with hydrogen bonding ligands such as water and formic acid. Generalized Kohn-Sham energy decomposition analysis decomposes the intermolecular binding energies into a frozen energy term, polarization, correlation, and/or dispersion energy terms, as well as terms of geometric relaxation and zero point energy. We observe that in each dimer the attractive polarization always increases upon ionization, enhancing binding in the cation and shifting the IP toward the red. For 9HFCA—H2O, a substantial decrease of the repulsive frozen energy in cation further shifts the IP toward red. For 9HFCA—HCOOH, the increase of the frozen energy actually occurs in the cation and shifts the IP toward blue. Consistent with the experimental measurements, our analysis provides new, non-intuitive perspectives on multiple hydrogen bonds interactions in carboxylic acids and water complexes.

  9. Injectable and Glucose-Responsive Hydrogels Based on Boronic Acid-Glucose Complexation.

    PubMed

    Dong, Yizhou; Wang, Weiheng; Veiseh, Omid; Appel, Eric A; Xue, Kun; Webber, Matthew J; Tang, Benjamin C; Yang, Xi-Wen; Weir, Gordon C; Langer, Robert; Anderson, Daniel G

    2016-08-30

    Injectable hydrogels have been widely used for a number of biomedical applications. Here, we report a new strategy to form an injectable and glucose-responsive hydrogel using the boronic acid-glucose complexation. The ratio of boronic acid and glucose functional groups is critical for hydrogel formation. In our system, polymers with 10-60% boronic acid, with the balance being glucose-modified, are favorable to form hydrogels. These hydrogels are shear-thinning and self-healing, recovering from shear-induced flow to a gel state within seconds. More importantly, these polymers displayed glucose-responsive release of an encapsulated model drug. The hydrogel reported here is an injectable and glucose-responsive hydrogel constructed from the complexation of boronic acid and glucose within a single component polymeric material.

  10. Oxidation of formic acid on platinum surfaces decorated with cobalt(III) macrocyclic complexes

    NASA Astrophysics Data System (ADS)

    Stevanović, S.; Babić-Samardžija, K.; Sovilj, S. P.; Tripković, A.; Jovanović, V. M.

    2009-09-01

    Platinum electrode decorated with three different mixed-ligand cobalt(III) complexes of the general formula [Co(Rdtc)cyclam](ClO4)2 [cyclam = 1,4,8,11-tetraazacyclotetradecane, Rdtc- = morpholine-(Morphdtc), piperidine-(Pipdtc), and 4-methylpiperidine-(4-Mepipdtc) dithiocarbamates, respectively] was used to study oxidation of formic acid in acidic solution. The complexes were adsorbed on differently prepared Pt surfaces, at open circuit potential. The preliminary results show increased catalytic activity of Pt for formic acid oxidation with complex ion adsorbed on the polycrystalline surfaces. The increase in catalytic activity depends on the structure of the complex applied and follows the order of metal-coordinated bidentate ligand as Morphdtc > Pipdtc > 4-Mepipdtc. Based on IR and NMR data, the main characteristics of the Rdtc ligands do not vary dramatically, but high symmetry of the corresponding complexes decreases in the same order. Accordingly, the complexes are distinctively more mobile, causing chemical interactions to occur on the surface with appreciable speed and enhanced selectivity. The effect of the complexes on catalytic activity presumably depends on structural changes on Pt surfaces caused by their adsorption.

  11. Non-covalent complexes of folic acid and oleic acid conjugated polyethylenimine: An efficient vehicle for antisense oligonucleotide delivery

    PubMed Central

    Yang, Shuang; Yang, Xuewei; Liu, Yan; Zheng, Bin; Meng, Lingjun; Lee, Robert J.; Xie, Jing; Teng, Lesheng

    2016-01-01

    Polyethylenimine (PEI) was conjugated to oleic acid (PEI-OA) and evaluated as a delivery agent for LOR-2501, an antisense oligonucleotide against ribonucleotide reductase R1 subunit. PEI-OA/LOR-2501 complexes were further coated with folic acid (FA/PEI-OA/LOR-2501) and evaluated in tumor cells. The level of cellular uptake of FA/PEI-OA/LOR-2501 was more than double that of PEI/LOR-2501 complexes, and was not affected by the expression level of folate receptor (FR) on the cell surface. Efficient delivery was seen in several cell lines. Furthermore, pathway specific cellular internalization inhibitors and markers were used to reveal the principal mechanism of cellular uptake. FA/PEI-OA/LOR-2501 significantly induced the downregulation of R1 mRNA and R1 protein. This novel formulation of FA/PEI-OA provides a reliable and highly efficient method for delivery of oligonucleotide and warrants further investigation. PMID:26263216

  12. APPLICATION OF FORMOHYDROXAMIC ACID IN NUCLEAR PROCESSING: SYNTHESIS AND COMPLEXATION WITH TECHNETIUM-99

    SciTech Connect

    Amber Wright; Edward Mausolf; Keri Campbell; Frederic Poineau; P. Paviet-Hartmann

    2010-05-01

    Acetohydroxamic acid (AHA) is an organic ligand planned for use in the Uranium Extraction (UREX) process. It reduces neptunium and plutonium, and the resultant hydrophilic complexes are separated from uranium by extraction with tributyl phosphate (TBP) in a hydrocarbon diluent. AHA undergoes hydrolysis to acetic acid which will impede the recycling of nitric acid. During recent discussions of the UREX process, it has been proposed to replace AHA by formohydroxamic acid (FHA). FHA will undergo hydrolysis to formic acid which is volatile, thus allowing the recycling of nitric acid. The reported reduction potentials of AHA and pertechnetate (TcO{sub 4}{sup -}) indicated that it may be possible for AHA to reduce technetium, altering its fate in the fuel cycle. At UNLV, it has been demonstrated that TcO{sub 4}{sup -} undergoes reductive nitrosylation by AHA under a variety of conditions. The resulting divalent technetium is complexed by AHA to form the pseudo-octahedral trans-aquonitrosyl (diacetohydroxamic)-technetium(II) complex ([Tc{sup II}(NO)(AHA){sub 2}H{sub 2}O]{sup +}). In this paper, we are reporting the synthesis of FHA and its complex formation with technetium along with the characterization of FHA crystals achieved by NMR and IR spectroscopy. Two experiments were conducted to investigate the complexation of FHA with Tc and the results were compared with previous data on AHA. The first experiment involved the elution of Tc from a Reillex HP anion exchange resin, and the second one monitored the complexation of technetium with FHA by UV-visible spectrophotometry.

  13. A remote Lewis acid trigger dramatically accelerates biaryl reductive elimination from a platinum complex.

    PubMed

    Liberman-Martin, Allegra L; Bergman, Robert G; Tilley, T Don

    2013-07-01

    A strategy for the control of electron density at a metal center is reported, which uses a remote chemical switch involving second-sphere Lewis acid binding that modulates electron density in the first coordination sphere. Binding of the Lewis acid B(C6F5)3 at remote nitrogen positions of a bipyrazine-diarylplatinum(II) complex accelerates biaryl reductive elimination by a factor of 64,000. PMID:23789917

  14. Structure and energy of formation of β- and γ-cyclodextrin complexes with amino acid enantiomers

    NASA Astrophysics Data System (ADS)

    Borisov, Yu. A.; Kiselev, S. S.

    2016-09-01

    The interaction between cyclodextrins (CyD), β-CyD, and γ-CyD, and the L- and D-optical isomers of several amino acids (Ala, Leu, His, Phe) are calculated using DFT. It is found that the L-forms of the investigated amino acids bond more strongly to CyD, due to the different numbers of hydrogen bonds that form. The structures of the resulting complexes are analyzed.

  15. Selective extraction and release using (EDTA-Ni)-layered double hydroxide coupled with catalytic oxidation of 3,3',5,5'-tetramethylbenzidine for sensitive detection of copper ion.

    PubMed

    Tang, Sheng; Chang, Yuepeng; Chia, Guo Hui; Lee, Hian Kee

    2015-07-23

    Copper is an important heavy metal in various biological processes. Many methods have been developed for detecting of copper ions (Cu(2+)) in aqueous samples. However, an easy, cheap, selective and sensitive method is still desired. In this study, a selective extraction-release-catalysis approach has been developed for sensitive detection of copper ion. Ethylenediaminetetraacetic acid (EDTA) chelated with nickel ion (Ni(2+)) were intercalated in a layered double hydroxide via a co-precipitation reaction. The product was subsequently applied as sorbent in dispersive solid-phase extraction for the enrichment of Cu(2+) at pH 6. Since Cu(2+) has a stronger complex formation constant with EDTA, Ni(2+) exchanged with Cu(2+) selectively. The resulting sorbent containing Cu(2+) was transferred to catalyze the 3,3',5,5'-tetramethylbenzidine oxidation reaction, since Cu(2+) could be released by the sorbent effectively and has high catalytic ability for the reaction. Blue light emitted from the oxidation product was measured by ultraviolet-visible spectrophotometry for the determination of Cu(2+). The extraction temperature, extraction time, and catalysis time were optimized. The results showed that this method provided a low limit of detection of 10nM, a wide linear range (0.05-100μM) and good linearity (r(2)=0.9977). The optimized conditions were applied to environmental water samples. Using Cu(2+) as an example, this work provided a new and interesting approach for the convenient and efficient detection of metal cations in aqueous samples. PMID:26231895

  16. Selective extraction and release using (EDTA-Ni)-layered double hydroxide coupled with catalytic oxidation of 3,3',5,5'-tetramethylbenzidine for sensitive detection of copper ion.

    PubMed

    Tang, Sheng; Chang, Yuepeng; Chia, Guo Hui; Lee, Hian Kee

    2015-07-23

    Copper is an important heavy metal in various biological processes. Many methods have been developed for detecting of copper ions (Cu(2+)) in aqueous samples. However, an easy, cheap, selective and sensitive method is still desired. In this study, a selective extraction-release-catalysis approach has been developed for sensitive detection of copper ion. Ethylenediaminetetraacetic acid (EDTA) chelated with nickel ion (Ni(2+)) were intercalated in a layered double hydroxide via a co-precipitation reaction. The product was subsequently applied as sorbent in dispersive solid-phase extraction for the enrichment of Cu(2+) at pH 6. Since Cu(2+) has a stronger complex formation constant with EDTA, Ni(2+) exchanged with Cu(2+) selectively. The resulting sorbent containing Cu(2+) was transferred to catalyze the 3,3',5,5'-tetramethylbenzidine oxidation reaction, since Cu(2+) could be released by the sorbent effectively and has high catalytic ability for the reaction. Blue light emitted from the oxidation product was measured by ultraviolet-visible spectrophotometry for the determination of Cu(2+). The extraction temperature, extraction time, and catalysis time were optimized. The results showed that this method provided a low limit of detection of 10nM, a wide linear range (0.05-100μM) and good linearity (r(2)=0.9977). The optimized conditions were applied to environmental water samples. Using Cu(2+) as an example, this work provided a new and interesting approach for the convenient and efficient detection of metal cations in aqueous samples.

  17. An enzyme-linked immunosorbent assay, using an EDTA-extracted antigen for the serology of Haemophilus pleuropneumoniae.

    PubMed

    Nicolet, J; Paroz, P; Krawinkler, M; Baumgartner, A

    1981-12-01

    An enzyme-linked immunosorbent assay (ELISA) was proposed as an alternative to the complement-fixation test (CF) for the detection of antibodies of Haemophilus pleuropneumoniae, agent of the pleuropneumonia in pigs. In tests done with different antigen-extraction procedures (including Tween 20, sodium dodecyl sulfate, aqueous phenol, sonification, and heat treatment at 120 C), ethylenediaminetetraacetic acid (EDTA) provided a satisfactorily reactive antigen. Chromatography purification on Sephacryl S200 improved the specificity of this antigen. Using hyperimmune rabbit sera, we investigated the specificity and the sensitivity of the ELISA with the EDTA-purified antigen of the different serotypes of H pleuropneumoniae on selected swine sera in herds with confirmed H pleuropneumoniae infection, from specific-pathogen-free animals showing doubtful CF reactions. The ELISA proved to be highly specific and more sensitive than the CF test. Furthermore, evidence of cross-reactions with H parasuis, a common bacteria isolated in swine populations, was not found.

  18. Morphology and Photocatalytic Properties of γ-Bi2MoO6 Tuned by Stirring and Surfactant EDTA Assistant

    NASA Astrophysics Data System (ADS)

    Mu, Jing Jing; Zheng, Gan Hong; Ma, Yong Qin

    2016-09-01

    Visible light-driven photocatalyst γ-Bi2MoO6 was prepared by a hydrothermal process, with stirring in the preparation process, and surfactant ethylenediaminetetraacetic acid (EDTA) addition in precursors. The obtained samples were characterized by x-ray diffraction technique, scanning electron microscopy, technology electron microscopy, and ultraviolet-visible diffraction reflectance spectra. The obtained results suggest that the stirring and EDTA addition have one strong influence on the morphology. Meanwhile, the formation mechanism of γ-Bi2MoO6 with different morphologies was also discussed. The catalytic activation of γ-Bi2MoO6 photocatalysts was evaluated by methyl blue under visible light irradiation. It was found that the photocatalytic properties change largely with surfactant assistant.

  19. a Microwave and AB Initio Study of the Nitric Acid - Trimethylamine Complex

    NASA Astrophysics Data System (ADS)

    Sedo, Galen; Leopold, Kenneth R.

    2009-06-01

    The microwave spectrum of the gas phase nitric acid - trimethylamine complex has been observed using Fourier transform microwave spectroscopy. The experimental rotational constants and (CH{_3}){_3}{^1}{^5}N-HNO{_3} isotope shifts are consistent with a complex in which the nitric acid proton forms a hydrogen bond to the nitrogen of the amine, similar to the experimentally determined structure of H{_3}N-HNO{_3} Analysis of the hyperfine structure in both the parent and (CH{_3}){_3}{^1}{^5}N-HNO{_3} spectra made it possible to determine, unambiguously, the quadrupole coupling constants of the {^1}{^5}N nuclei in both the nitric acid and trimethylamine moieties. Ab initio calculations, using the MP2/6-311++G(2df,2pd) level of theory and basis set, have been performed and are in quantitative agreement with the available experimental data. Both the experimentally determined quadrupole coupling constants and the ab initio structure have been used to assess the degree of proton transfer occurring in the nitric acid - trimethylamine complex. These results will be compared to those obtained for the H{_3}N-HNO{_3} and HNO{_3}-(H{_2}O){_n} [n = 0 - 3] complexes and discussed in terms of how binding partner basicity and the number of solvent molecules influence the incipient ionization of nitric acid moiety. M. E. Ott, and K. R. Leopold, J. Phys. Chem. A 1999, 103,1322-1328.

  20. Asymmetric epoxidation of allylic alcohols catalyzed by vanadium-binaphthylbishydroxamic Acid complex.

    PubMed

    Noji, Masahiro; Kobayashi, Toshihiro; Uechi, Yuria; Kikuchi, Asami; Kondo, Hisako; Sugiyama, Shigeo; Ishii, Keitaro

    2015-03-20

    A vanadium-binaphthylbishydroxamic acid (BBHA) complex-catalyzed asymmetric epoxidation of allylic alcohols is described. The optically active binaphthyl-based ligands BBHA 2a and 2b were synthesized from (S)-1,1'-binaphthyl-2,2'-dicarboxylic acid and N-substituted-O-trimethylsilyl (TMS)-protected hydroxylamines via a one-pot, three-step procedure. The epoxidations of 2,3,3-trisubstituted allylic alcohols using the vanadium complex of 2a were easily performed in toluene with a TBHP water solution to afford (2R)-epoxy alcohols in good to excellent enantioselectivities.

  1. Bioreduction of Uranium(VI) Complexed with Citric Acid by Clostridia Affects its Structure and Mobility

    SciTech Connect

    Francis, A.; Dodge, C

    2008-01-01

    Uranium contamination of the environment from mining and milling operations, nuclear-waste disposal, and ammunition use is a widespread global problem. Natural attenuation processes such as bacterial reductive precipitation and immobilization of soluble uranium is gaining much attention. However, the presence of naturally occurring organic ligands can affect the precipitation of uranium. Here, we report that the anaerobic spore-forming bacteria Clostridia, ubiquitous in soils, sediments, and wastes, capable of reduction of Fe(III) to Fe(II), Mn(IV) to Mn(II), U(VI) to U(IV), Pu(IV) to Pu(III), and Tc(VI) to Tc(IV); reduced U(VI) associated with citric acid in a dinuclear 2:2 U(VI):citric acid complex to a biligand mononuclear 1:2 U(IV):citric acid complex, which remained in solution, in contrast to reduction and precipitation of uranium. Our findings show that U(VI) complexed with citric acid is readily accessible as an electron acceptor despite the inability of the bacterium to metabolize the complexed organic ligand. Furthermore, it suggests that the presence of organic ligands at uranium-contaminated sites can affect the mobility of the actinide under both oxic and anoxic conditions by forming such soluble complexes.

  2. Competition of hydrogen bonds and halogen bonds in complexes of hypohalous acids with nitrogenated bases.

    PubMed

    Alkorta, Ibon; Blanco, Fernando; Solimannejad, Mohammad; Elguero, Jose

    2008-10-30

    A theoretical study of the complexes formed by hypohalous acids (HOX, X = F, Cl, Br, I, and At) with three nitrogenated bases (NH 3, N 2, and NCH) has been carried out by means of ab initio methods, up to MP2/aug-cc-pVTZ computational method. In general, two minima complexes are found, one with an OH...N hydrogen bond and the other one with a X...N halogen bond. While the first one is more stable for the smallest halogen derivatives, the two complexes present similar stabilities for the iodine case and the halogen-bonded structure is the most stable one for the hypoastatous acid complexes. PMID:18837495

  3. Complexation Constants of Ubiquinone,0 and Ubiquinone,10 with Nucleosides and Nucleic Acid Bases

    NASA Astrophysics Data System (ADS)

    Rahawi, Kassim Y.; Shanshal, Muthana

    2008-02-01

    UV spectrophotometric measurements were done on mixtures of the ubiquinones Ub,0 and Ub,10 in their monomeric form (c < 10-5 mol/l) with the nucleosides; adenosine, cytidine, 2'-desoxyadenosine, 2'-desoxy-quanosine, guanosine and thymidine, as well as the nucleic acid bases; adenine, cytosine, hypoxanthine, thymine and uracil. Applying the Liptay method, it was found that both ubiquinones form 1 : 1 interaction complexes with the nucleic acid components. The complexation constants were found in the order of 105 mol-1. The calculated ΔG values were negative (˜-7.0 kcal/mol), suggesting a favoured hydrogen bridge formation. This is confirmed by the positive change of the entropy ΔS. The complexation enthalpies ΔH for all complexes are negative, suggesting exothermal interactions.

  4. Experimental and theoretical investigation of the complexation of methacrylic acid and diisopropyl urea.

    PubMed

    Pogány, Peter; Razali, Mayamin; Szekely, Gyorgy

    2017-01-01

    The present paper explores the complexation ability of methacrylic acid which is one of the most abundant functional monomer for the preparation of molecularly imprinted polymers. Host-guest interactions and the mechanism of complex formation between methacrylic acid and potentially genotoxic 1,3-diisopropylurea were investigated in the pre-polymerization solution featuring both experimental (NMR, IR) and in silico density functional theory (DFT) tools. The continuous variation method revealed the presence of higher-order complexes and the appearance of self-association which were both taken into account during the determination of the association constants. The quantum chemical calculations - performed at B3LYP 6-311++G(d,p) level with basis set superposition error (BSSE) corrections - are in agreement with the experimental observations, reaffirming the association constants and justifying the validity of computational investigation of such systems. Furthermore, natural bond orbital analysis was carried out to appraise the binding properties of the complexes.

  5. Experimental and theoretical investigation of the complexation of methacrylic acid and diisopropyl urea.

    PubMed

    Pogány, Peter; Razali, Mayamin; Szekely, Gyorgy

    2017-01-01

    The present paper explores the complexation ability of methacrylic acid which is one of the most abundant functional monomer for the preparation of molecularly imprinted polymers. Host-guest interactions and the mechanism of complex formation between methacrylic acid and potentially genotoxic 1,3-diisopropylurea were investigated in the pre-polymerization solution featuring both experimental (NMR, IR) and in silico density functional theory (DFT) tools. The continuous variation method revealed the presence of higher-order complexes and the appearance of self-association which were both taken into account during the determination of the association constants. The quantum chemical calculations - performed at B3LYP 6-311++G(d,p) level with basis set superposition error (BSSE) corrections - are in agreement with the experimental observations, reaffirming the association constants and justifying the validity of computational investigation of such systems. Furthermore, natural bond orbital analysis was carried out to appraise the binding properties of the complexes. PMID:27419640

  6. Spectrophotometric and some thermodynamic parameters of the charge transfer complexation between chloranilic acid and chlorpheniramine.

    PubMed

    Ofoefule, S I; Ajali, U

    2001-01-01

    The principle of charge transfer complexation involving a pi-acceptor (chloranilic acid) and an n-donor (chlorpheniramine) was utilized in the assay of the later in its pure form and in its tablet dosage forms. Some thermodynamic parameters of the complex such as association constant (Kc), molar absorptivity (epsilon c), free energy change (delta G degree), enthalpy (delta H degree) and entropy (delta S degree) changes were determined to establish the stability of the complex and the optimum conditions for the complex formation. The values obtained for these thermodynamic parameters indicated that the complex formed between this two chemical entities is highly stable. Assay of chlorpheniramine in its pure form and in its tablet dosage forms gave high percentage recoveries. The principle of charge transfer complexation could therefore be employed in the colorimetric assay of chlorpheniramine in its tablet dosage forms.

  7. Use of EDTA in modified kinetic testing for contaminated drainage prediction from waste rocks: case of the Lac Tio mine.

    PubMed

    Plante, Benoît; Benzaazoua, Mostafa; Bussière, Bruno; Kandji, El-Hadji-Babacar; Chopard, Aurélie; Bouzahzah, Hassan

    2015-05-01

    The tools developed for acid mine drainage (AMD) prediction were proven unsuccessful to predict the geochemical behavior of mine waste rocks having a significant chemical sorption capacity, which delays the onset of contaminated neutral drainage (CND). The present work was performed in order to test a new approach of water quality prediction, by using a chelating agent solution (0.03 M EDTA, or ethylenediaminetetraacetic acid) in kinetic testing used for the prediction of the geochemical behavior of geologic material. The hypothesis underlying the proposed approach is that the EDTA solution should chelate the metals as soon as they are released by sulfide oxidation, inhibiting their sorption or secondary precipitation, and therefore reproduce a worst-case scenario where very low metal attenuation mechanisms are present in the drainage waters. Fresh and weathered waste rocks from the Lac Tio mine (Rio tinto, Iron and Titanium), which are known to generate Ni-CND at the field scale, were submitted to small-scale humidity cells in control tests (using deionized water) and using an EDTA solution. Results show that EDTA effectively prevents the metals to be sorbed or to precipitate as secondary minerals, therefore enabling to bypass the delay associated with metal sorption in the prediction of water quality from these materials. This work shows that the use of a chelating agent solution is a promising novel approach of water quality prediction and provides general guidelines to be used in further studies, which will help both practitioners and regulators to plan more efficient management and disposal strategies of mine wastes. PMID:25604563

  8. [Removal of heavy metals from extract of Angelica sinensis by EDTA-modified chitosan magnetic adsorbent].

    PubMed

    Ren, Yong; Sun, Ming-Hui; Peng, Hong; Huang, Kai-Xun

    2013-11-01

    The concentrations of heavy metals in the extracting solutions of traditional Chinese medicine are usually very low. Furthermore, a vast number of organic components contained in the extracting solutions would be able to coordinate with heavy metals, which might lead to great difficulty in high efficient removal of them from the extracting solutions. This paper was focused on the removal of heavy metals of low concentrations from the extracting solution of Angelica sinensis by applying an EDTA-modified chitosan magnetic adsorbent (EDTA-modified chitosan/SiO2/Fe3O4, abbreviated as EDCMS). The results showed that EDCMS exhibited high efficiency for the removal of heavy metals, such as Cu, Cd and Pb, e.g. the removal percentage of Cd and Pb reached 90% and 94.7%, respectively. Besides, some amounts of other heavy metals like Zn and Mn were also removed by EDCMS. In addition, the total solid contents, the amount of ferulic acid and the HPLC fingerprints of the extracting solution were not changed significantly during the heavy metal removal process. These results indicate that EDCMS may act as an applicable and efficient candidate for the removal of heavy metals from the extracting solution of A. sinensis.

  9. Defluoridation of water using dicarboxylic acids mediated chitosan-polyaniline/zirconium biopolymeric complex.

    PubMed

    Muthu Prabhu, Subbaiah; Meenakshi, Sankaran

    2016-04-01

    The present investigation describes the preparation of hydrogen bonded chitosan-polyaniline/zirconium biopolymeric matrix by grafting method under dicarboxylic acid medium for the removal of fluoride, first time. Herein, the dicarboxylic acids, oxalic acid, malonic acid, succinic acid were used as medium. The synthesized complex was characterized by usual analytical techniques like FTIR, XRD, SEM and EDAX analysis. From the batch equilibrium experiments, the maximum defluoridation capacity (DC) was found to be 8.713 mg/g at room temperature with the minimum contact time of 24 min at 100mg of the sorbent dosage. The temperature study results of adsorption kinetics showed the adsorption behavior could be better described by the pseudo-second-order equation than pseudo-first-order kinetic model. The adsorption isotherm was well fitted by the Freundlich equation rather than Langmuir and D-R isotherms. The mechanism of fluoride removal was ligand exchange at neutral pH and electrostatic attraction at acidic pH of the medium. Regeneration studies were carried out to identify the best regenerant which makes the process cost-effective. Conclusions of this work demonstrate the potential applicability of the dicarboxylic acid mediated chitosan-polyaniline/zirconium complex as an effective adsorbent for fluoride removal from water. PMID:26706844

  10. Defluoridation of water using dicarboxylic acids mediated chitosan-polyaniline/zirconium biopolymeric complex.

    PubMed

    Muthu Prabhu, Subbaiah; Meenakshi, Sankaran

    2016-04-01

    The present investigation describes the preparation of hydrogen bonded chitosan-polyaniline/zirconium biopolymeric matrix by grafting method under dicarboxylic acid medium for the removal of fluoride, first time. Herein, the dicarboxylic acids, oxalic acid, malonic acid, succinic acid were used as medium. The synthesized complex was characterized by usual analytical techniques like FTIR, XRD, SEM and EDAX analysis. From the batch equilibrium experiments, the maximum defluoridation capacity (DC) was found to be 8.713 mg/g at room temperature with the minimum contact time of 24 min at 100mg of the sorbent dosage. The temperature study results of adsorption kinetics showed the adsorption behavior could be better described by the pseudo-second-order equation than pseudo-first-order kinetic model. The adsorption isotherm was well fitted by the Freundlich equation rather than Langmuir and D-R isotherms. The mechanism of fluoride removal was ligand exchange at neutral pH and electrostatic attraction at acidic pH of the medium. Regeneration studies were carried out to identify the best regenerant which makes the process cost-effective. Conclusions of this work demonstrate the potential applicability of the dicarboxylic acid mediated chitosan-polyaniline/zirconium complex as an effective adsorbent for fluoride removal from water.

  11. Photochemical transformation of an iron(III)-arsenite complex in acidic aqueous solution.

    PubMed

    Pozdnyakov, Ivan P; Ding, Wei; Xu, Jing; Chen, Long; Wu, Feng; Grivin, Vjacheslav P; Plyusnin, Victor F

    2016-03-01

    Surface complexation between arsenious acid anions (As(III)) and ferric (hydr)oxides in water is important for the transformation and transfer of inorganic arsenic species. The mechanisms of formation and the photochemistry of dissolved Fe(III)-As(III) complexes in acidic aqueous solution are still unclear. Here, the photooxidation of As(III) in the presence of Fe(III) ions in acidic media has been investigated by laser flash and steady-state photolysis. At low arsenite concentrations (<1 mM), As(III) is oxidized by the ˙OH radical generated by photolysis of the FeOH(2+) complex. At higher arsenite concentrations (>10 mM), photoactive Fe(III)-As(III) complexes are formed (ϕ≈ 0.012). At all arsenite concentrations, a white FeAsO4 colloid is formed during As(III) photolysis in the presence of Fe(III) ions. Solid Fe(III)-As(III) complexes have been prepared and characterized, and the photochemical transformation of As(III) into As(V) in solid Fe(III)-As(III) complexes has been confirmed. These findings are important for a better understanding of the evolution of As(III) species under environmental conditions and should provide guidance for detoxification of As(III)-polluted water systems.

  12. Metallurgical and Biological Activity of Peroxo Complexes of Molybdenum (VI) Containing Organic Acid and Amine Bases

    NASA Astrophysics Data System (ADS)

    Nasrin, Jahanara; Saidul Islam, M.

    This study describes with the preparation, characterization and bioactivity of peroxo complexes [A: MoO(O2)(gly)(Q); B: MoO(O2)(ala)(2-pic)]of Mo(VI)] containing organic acid and amine bases. Both the complexes A and B were characterized by a variety of physicochemical techniques, viz., elemental analyses, molar conductivity, IR, NMR and electronic spectral studies. The analytical data were in good agreement with the proposed emperical formulae of both the complexes. The molar conductance values indicated both the complexes are non-electrolytes in DMF revealing that the anions are covalently bonded in all the cases. The magnetic moment values indicated that both the complexes were dimagnetic in nature suggesting that there were no changes in the oxidation states of the metal ions upon complexation. The electronic spectral data of the complexes A and B showed bands at 315-355 nm region due to the charge transfers band only. The antimicrobial properties of the peroxo complexes of Mo(VI) indicated that both the complexes were stronger antibacterial and antifungal agents. However, the highest antifungal activity was shown in the complex B against A. niger (16 mm) while the complex A of Mo(VI) showed lowest activity (10 mm). The MIC experiment showed that the complex B of Mo(VI) were more potent against all the bacteria tested than the complex A. Results showed that the complex A of Mo(VI) exhibits more toxic to brine shrimp compared to complex B of Mo(VI) indicating the lower values of LC50 for both the exposure 16 and 36 h.

  13. Thermodynamic Features of Benzene-1,2-Diphosphonic Acid Complexes with Several Metal Ions

    SciTech Connect

    Syouhei Nishihama; Ryan P. Witty; Leigh R Martin; Kenneth L. Nash

    2013-08-01

    Among his many contributions to the advancement of f-element chemistry and separation science, Professor Gregory R. Choppin’s research group completed numerous investigations featuring the application of distribution techniques to the determination of metal complexation equilibrium quotients. Most of these studies focused on the chemistry of lanthanide and actinide complexes. In keeping with that tradition, this report discusses the complex formation equilibrium constants for complexes of trivalent europium (Eu3+) with benzene-1,2-diphosphonic acid (H4BzDP) determined using solvent extraction distribution experiments in 0.2 M (Na,H)ClO4 media in the temperature range of 5 – 45 degrees C. Protonation constants for HnBzDP4-n and stoichiometry and stability of BzDP4- complexes with Zn2+, Ni2+, and Cu2+ have also been determined using potentiometric titration (at I = 0.1 M) and 31P NMR spectroscopy. Heats of protonation of HnBzDPn-4 species have been determined by titration calorimetry. From the temperature dependence of the complex Eu3+-HnBzDPn-4 equilibrium constant, a composite enthalpy (?H = -15.1 (+/-1.0) kJ mol-1) of complexation has been computed. Comparing these thermodynamic parameters with literature reports on other diphosphonic acids and structurally similar carboxylic acids indicates that exothermic heats of complexation are unique to the Eu-BzDP system. Comparisons with thermodynamic data from the literature indicate that the fixed geometry imposed by the benzene ring enhances complex stability.

  14. EDTA-dependent pseudothrombocytopenia. Association with antiplatelet and antiphospholipid antibodies.

    PubMed

    Bizzaro, N; Brandalise, M

    1995-01-01

    In a study of 88 patients with EDTA-dependent pseudothrombocytopenia (PTCP), EDTA-dependent antiplatelet antibodies were seen in the sera of 72 (81.8%) patients (44 IgM, 25 IgG, and 3 IgA). The same sera also were tested for anticardiolipin antibodies (aCL), and 56 (63.6%) patients had sera that also were reactive for aCL (33 IgM, 21 IgG, and 2 IgA). The 16 patients who were negative for antiplatelet antibodies also were negative for aCL antibody. Overall concordance between antiplatelet and aCL antibodies was 82.9%; the correlation between antiplatelet and aCL antibody isotype distribution was 82.1%. Following cardiolipin absorption, most of the PTCP-sera were negative for antiplatelet activity, and no longer reproduced platelet clumping when incubated with normal blood. This finding showed that the antiplatelet antibodies cross-reacted with negatively charged phospholipids. However, after absorption on normal platelets, complete inhibition of aCL activity was observed in 34 (60.7%), and partial inhibition in 14 of the 56 patients who were aCL positive. These findings support the hypothesis that antibody subpopulations (naturally occurring autoantibodies) directed against negatively charged phospholipids can bind to antigens modified by EDTA on the platelet membrane, and may be responsible for PTCP genesis. PMID:7817934

  15. Isolation of a multi-enzyme complex of fatty acid oxidation from Escherichia coli.

    PubMed Central

    Binstock, J F; Pramanik, A; Schulz, H

    1977-01-01

    A multi-enzyme complex of fatty acid oxidation has been isolated from E. coli B cells and has been purified to near homogeneity by a simple two-step procedure. The complex exhibits thiolase (EC 2.3.1.9), enoyl-CoA hydratase (EC 4.2.1.17), and 3-hydroxyacyl-CoA dehydrogenase (EC 1.1.1.35) activities towards short-, medium-, and long-chain substrates. The complex has been estimated to have a molecular weight of approximately 300,000 and is apparently composed of two types of subunits with molecular weights of 78,000 and 42,000. Images PMID:322129

  16. Characterization of folic acid/native cyclodextrins host-guest complexes in solution

    NASA Astrophysics Data System (ADS)

    Ceborska, Magdalena; Zimnicka, Magdalena; Wszelaka-Rylik, Małgorzata; Troć, Anna

    2016-04-01

    The complexation of folic acid (FA) with native cyclodextrins was studied and this process was used for the comparison of 1H NMR, ITC and ESIMS for the evaluation of association constants. The stability increases in the series: α-cyclodextrin/FA < γ-cyclodextrin/FA < β-cyclodextrin/FA. 1H NMR and ITC gave comparable results in regard to association constant values, while results obtained for MS were considerably higher due to different interactions (electrostatic instead of hydrophobic) responsible for the stabilization of the complexes. The dimerization of FA in water was also studied, as well as its impact on the process of complexation with native cyclodextrins.

  17. Structural organization of films based on polyaniline/polysulfonic acid complexes depending on the synthesis method

    SciTech Connect

    Simagina, L. V. Gaynutdinov, R. V.; Stepina, N. D.; Sorokina, K. L.; Morozova, O. V.; Shumakovich, G. P.; Yaropolov, A. I.; Tolstikhina, A. L.

    2010-07-15

    The optical properties and morphology of complexes based on polyaniline (PANI) and poly(2-acrylamido-2-methyl-1-propanesulfonic acid) (PAMPS), depending on their synthesis conditions, have been characterized by UV-visible spectroscopy and atomic force microscopy. The dependence of the electron absorption spectra of PANI/PAMPS complexes and the surface topography of their films on the initiation way of PANI formation (chemical and enzymatic) and the use of promoters of aniline polymerization has been investigated. The aniline polymerization kinetics with and without polymerization promoters has been studied. All PANI/PAMPS complexes are found to have a nanocomposite time-stable structure.

  18. New 3,4-diaminobenzoic acid Schiff base compounds and their complexes: Synthesis, characterization and thermodynamics

    NASA Astrophysics Data System (ADS)

    Mohammadi, Khosro; Niad, Mahmood; Jafari, Tahereh

    2014-03-01

    Some new tetradentate Schiff base ligands (H3L) were prepared via condensation of 3,4-diaminobenzoic acid with 2-hydroxybenzaldehyde derivatives, such as 3,4-bis((E)-2,4-dihydroxybenzylideneamino)benzoic acid (H3L1), 3,4-bis((E)-2-hydroxy-3-methoxybenzylideneamino)benzoic acid (H3L2) and 3,4-bis((E)-5-bromo-2-hydroxybenzylideneamino)benzoic acid (H3L4). Additionally, a tetradentate Schiff base ligand 3,4-bis((E)-2-hydroxybenzylideneamino)benzoic acid (H3L3) and its complexes were synthesized. Their metal complexes of Co(II), Ni(II), Cu(II) and Zn(II) were prepared in good yields from the reaction of the ligands with the corresponding metal acetate. They were characterized based on IR, 1H NMR, Mass spectroscopy and UV-Vis spectroscopy. Also, the formation constants of the complexes were measured by UV-Vis spectroscopic titration at constant ionic strength 0.1 M (NaClO4), at 25 °C in dimethylformamide (DMF) as a solvent.

  19. New 3,4-diaminobenzoic acid Schiff base compounds and their complexes: synthesis, characterization and thermodynamics.

    PubMed

    Mohammadi, Khosro; Niad, Mahmood; Jafari, Tahereh

    2014-03-25

    Some new tetradentate Schiff base ligands (H3L) were prepared via condensation of 3,4-diaminobenzoic acid with 2-hydroxybenzaldehyde derivatives, such as 3,4-bis((E)-2,4-dihydroxybenzylideneamino)benzoic acid (H3L(1)), 3,4-bis((E)-2-hydroxy-3-methoxybenzylideneamino)benzoic acid (H3L(2)) and 3,4-bis((E)-5-bromo-2-hydroxybenzylideneamino)benzoic acid (H3L(4)). Additionally, a tetradentate Schiff base ligand 3,4-bis((E)-2-hydroxybenzylideneamino)benzoic acid (H3L(3)) and its complexes were synthesized. Their metal complexes of Co(II), Ni(II), Cu(II) and Zn(II) were prepared in good yields from the reaction of the ligands with the corresponding metal acetate. They were characterized based on IR, (1)H NMR, Mass spectroscopy and UV-Vis spectroscopy. Also, the formation constants of the complexes were measured by UV-Vis spectroscopic titration at constant ionic strength 0.1M (NaClO4), at 25 °C in dimethylformamide (DMF) as a solvent.

  20. Zirconium complexes with lactic acid in the solution and solid states

    NASA Astrophysics Data System (ADS)

    Demkowicz, Paul Andrew

    Lactic acid complexes of zirconium are used in a great number of industrial applications. Among these is their use as crosslinking agents for hydraulic fracturing fluids used in secondary oil recovery operations. Because of a poor understanding of zirconium lactate complex chemistry and crosslinking reactions, however, the design of superior fluid systems is often not guided by sound chemical principles and leads to empirical guesswork. Zirconium lactate solutions were characterized using Fourier transform infrared (FT-IR) spectroscopy, 1H, 13C, and 17O nuclear magnetic resonance (NMR) spectroscopy, and potentiometry. The results indicate that lactic acid is coordinated bidentate to zirconium via the alcohol and carboxylate groups. The average number of lactate ligands per zirconium ion is approximately 2 and is demonstrated to be relatively constant from pH 4--9. The lability of the lactate complexes increases as the pH is decreased. The NMR data reveal that there are both large and small complex molecules present in solution, with the size of the complex depending on the extent of zirconium hydrolysis. Large complexes consist of lactic acid coordinated to polynuclear zirconium hydroxy ions. The molecular size of these complexes is sufficient to hinder their tumbling in solution and cause broadening of the measured NMR signals. Small complexes involve lactic acid coordinated to hydroxylated species containing fewer zirconium ions, such that the rotational motion in solution is sufficiently rapid to result in narrow NMR signals. Zirconium lactate complexes were precipitated from solution and analyzed in the solid state using FT-IR spectroscopy, 13C magic angle spinning (MAS) NMR spectroscopy, elemental analysis, thermal gravitational analysis, and x-ray diffraction. Two distinct types of crystalline compounds were synthesized with four lactate ligands per zirconium ion. The coordination of lactic acid to zirconium is different in the two compounds, with one showing

  1. Methods of staining target chromosomal DNA employing high complexity nucleic acid probes

    DOEpatents

    Gray, Joe W.; Pinkel, Daniel; Kallioniemi, Ol'li-Pekka; Kallioniemi, Anne; Sakamoto, Masaru

    2006-10-03

    Methods and compositions for staining based upon nucleic acid sequence that employ nucleic acid probes are provided. Said methods produce staining patterns that can be tailored for specific cytogenetic analyses. Said probes are appropriate for in situ hybridization and stain both interphase and metaphase chromosomal material with reliable signals. The nucleic acid probes are typically of a complexity greater than 50 kb, the complexity depending upon the cytogenetic application. Methods and reagents are provided for the detection of genetic rearrangements. Probes and test kits are provided for use in detecting genetic rearrangements, particularly for use in tumor cytogenetics, in the detection of disease related loci, specifically cancer, such as chronic myelogenous leukemia (CML), retinoblastoma, ovarian and uterine cancers, and for biological dosimetry. Methods and reagents are described for cytogenetic research, for the differentiation of cytogenetically similar but genetically different diseases, and for many prognostic and diagnostic applications.

  2. Synthesis, characterisation and biological evaluation of copper and silver complexes based on acetylsalicylic acid.

    PubMed

    Rubner, Gerhard; Bensdorf, Kerstin; Wellner, Anja; Bergemann, Silke; Gust, Ronald

    2011-10-01

    Metalcarbonyl complexes with ligands derived from acetylsalicylic acid demonstrated high cytotoxic potential against various tumor cell lines and strong inhibition of the cyclooxygenase enzymes COX-1 and 2. In this study we tried to achieve comparable effects with [alkyne]silver or copper trifluoromethanesulfonate complexes which are more hydrophilic then the uncharged metalcarbonyl derivatives. All compounds were evaluated for growth inhibition against breast (MCF-7, MDA-MB 231) and colon cancer (HT-29) cell lines and for COX-1 and COX-2 inhibitory effects at isolated isoenzymes. Pure ligands showed neither cytotoxic nor COX-inhibitory effects. While the silver complexes of (but-2-ynyl)-2-acetoxybenzoate (But-ASS-Ag) and (but-2-yne-1,4-diyl)-bis(2-acetoxybenzoate) (Di-ASS-But-Ag) were strong cytostatics, only the copper complex Di-ASS-But-Cu was active. At the COX enzymes the complexes were more effective than their ligands and aspirin.

  3. Carotenoids, but not vitamin A, improve iron uptake and ferritin synthesis by Caco-2 cells from ferrous fumarate and NaFe-EDTA.

    PubMed

    García-Casal, María N; Leets, Irene

    2014-04-01

    Due to the high prevalence of iron and vitamin A deficiencies and to the controversy about the role of vitamin A and carotenoids in iron absorption, the objectives of this study were to evaluate the following: (1) the effect of a molar excess of vitamin A as well as the role of tannic acid on iron uptake by Caco-2 cells; (2) iron uptake and ferritin synthesis in presence of carotenoids without pro-vitamin A activity: lycopene, lutein, and zeaxantin; and (3) iron uptake and ferritin synthesis from ferrous fumarate and NaFe-EDTA. Cells were incubated 1 h at 37 °C in PBS pH 5.5, containing (59) Fe and different iron compounds. Vitamin A, ferrous fumarate, β-carotene, lycopene, lutein, zeaxantin, and tannic acid were added to evaluate uptake. Ferritin synthesis was measured 24 h after uptake experiments. Vitamin A had no effect on iron uptake by Caco-2 cells, and was significantly lower from NaFe-EDTA than from ferrous fumarate (15.2 ± 2.5 compared with 52.5 ± 8.3 pmol Fe/mg cell protein, respectively). Carotenoids increase uptake up to 50% from fumarate and up to 300% from NaFe-EDTA, since absorption from this compound is low when administered alone. We conclude the following: (1) There was no effect of vitamin A on iron uptake and ferritin synthesis by Caco-2cells. (2) Carotenoids significantly increased iron uptake from ferrous fumarate and NaFe-EDTA, and were capable of partially overcoming the inhibition produced by tannic acid. (3) Iron uptake by Caco-2 cell from NaFe-EDTA was significantly lower compared to other iron compounds, although carotenoids increased and tannic acid inhibited iron uptake comparably to ferrous fumarate.

  4. A comparative study of the complexation of uranium(VI) withoxydiacetic acid and its amide derivatives

    SciTech Connect

    Rao, Linfeng; Tian, Guoxin

    2005-05-01

    There has been significant interest in recent years in the studies of alkyl-substituted amides as extractants for actinide separation because the products of radiolytic and hydrolytic degradation of amides are less detrimental to separation processes than those of organophosphorus compounds traditionally used in actinide separations. Stripping of actinides from the amide-containing organic solvents is relatively easy. In addition, the amide ligands are completely incinerable so that the amount of secondary wastes generated in nuclear waste treatment could be significantly reduced. One group of alkyl-substituted oxa-diamides have been shown to be promising in the separation of actinides from nuclear wastes. For example, tetraoctyl-3-oxa-glutaramide and tetraisobutyl-oxa-glutaramide form actinide complexes that can be effectively extracted from nitric acid solutions. To understand the thermodynamic principles governing the complexation of actinides with oxa-diamides, we have studied the complexation of U(VI) with dimethyl-3-oxa-glutaramic acid (DMOGA) and tetramethyl-3-oxa-glutaramide (TMOGA) in aqueous solutions, in comparison with oxydiacetic acid (ODA) (Figure 1). Previous studies have indicated that the complexation of U(VI) with ODA is strong and entropy-driven. Comparing the results for DMOGA and TMOGA with those for ODA could provide insight into the energetics of amide complexation with U(VI) and the relationship between the thermodynamic properties and the ligand structure.

  5. Probing the structure of nucleic acids with Ni(II) complexes

    SciTech Connect

    Chen, Xiaoying.

    1992-01-01

    The structure of nucleic acids determines their biological function. Interest in the development of novel probes from structures of nucleic acid has led to the discovery of conformation-specific oxidation of guanine sites in DNA and RNA using Ni(II) complexes. The reaction is highly dependent upon the nature of Ni(II) complexes with the most important feature of a strong in-plane ligand field. The unique properties of Ni(II) complexes combining redox and coordination features provide sensitive probes for nucleic acid conformation. One of these nickel complexes, NiCR, has been shown to selectively promote cleavage of DNA at guanine sites held accessible through the formation of unusual secondary structures such as ends, mismatches, bulges and loops. An unique mechanism for the base and conformation-specific oxidation of DNA promoted by Ni(II) complexes is proposed, involving direct ligation of nickel to N-7 of guanine delivering a non-diffusible oxidizing species. NiCR has been proved to be a sensitive and predictable probe for the tertiary structure of RNAs. The specific sites of oxidation of tRNS[sup phe] promoted by NiCR correspond to the most accessible guanine residues determined by theoretic calculations. NiCR has also been successfully applied to probe the tertiary structure of self-splicing Tetrahymena pre-rRNA intron, and has provided important information about the folding of this intron, especially in the region of the catalytic core.

  6. Theoretical and spectroscopic studies of lanthanum (III) complex of 5-aminoorotic acid

    NASA Astrophysics Data System (ADS)

    Kostova, Irena; Peica, Niculina; Kiefer, Wolfgang

    2006-09-01

    The lanthanum (III) complex of 5-aminoorotic acid (HAOA) was synthesized and its structure was determined by means of elemental analysis and IR, Raman, and 1H NMR spectroscopies. Significant differences in the IR, Raman, and 1H NMR spectra of the complex were observed as compared to the spectra of the ligand. The geometry of 5-aminoorotic acid was computed and optimized with the Gaussian 03 program employing the B3PW91 and B3LYP methods with the 6-311++G and LANL2DZ basis sets, while the geometry of the La(III) complex of 5-aminoorotic acid was also calculated and optimized with B3PW91/LANL2DZ and B3LYP/LANL2DZ methods. The density functional calculations revealed that the binding mode in the complex was bidentate through the carboxylic oxygen atoms. Detailed vibrational analysis of HAOA and La(III)-AOA systems based on both the calculated and experimental spectra confirmed the suggested metal-ligand binding mode. The density functional theory (DFT) calculated geometries, harmonic vibrational wavenumbers including IR and Raman scattering activities for the ligand and its La(III) complex were in good agreement with the experimental data, a complete vibrational assignment being proposed.

  7. Synthesis, crystal structure, and thermal decomposition of the cobalt(II) complex with 2-picolinic acid.

    PubMed

    Li, Di; Zhong, Guo-Qing

    2014-01-01

    The cobalt(II) complex of 2-picolinic acid (Hpic), namely, [Co(pic)₂(H₂O)₂] · 2H₂O, was synthesized with the reaction of cobalt acetate and 2-picolinic acid as the reactants by solid-solid reaction at room temperature. The composition and structure of the complex were characterized by elemental analysis, infrared spectroscopy, single crystal X-ray diffraction, and thermogravimetry-differential scanning calorimetry (TG-DSC). The crystal structure of the complex belongs to monoclinic system and space group P2(1)/n, with cell parameters of a = 9.8468(7) Å, b = 5.2013(4) Å, c = 14.6041(15) Å, β = 111.745(6)°, V = 747.96(11) ų, Z = 2, D(c) = 1.666 g cm⁻³, R₁ = 0.0297, and wR₂ = 0.0831. In the title complex, the Co(II) ion is six-coordinated by two pyridine N atoms and two carboxyl O atoms from two 2-picolinic acid anions, and two O atoms from two H2O molecules, and forming a slightly distorted octahedral geometry. The thermal decomposition processes of the complex under nitrogen include dehydration and pyrolysis of the ligand, and the final residue is cobalt oxalate at about 450°C.

  8. Synthesis, Crystal Structure, and Thermal Decomposition of the Cobalt(II) Complex with 2-Picolinic Acid

    PubMed Central

    Li, Di

    2014-01-01

    The cobalt(II) complex of 2-picolinic acid (Hpic), namely, [Co(pic)2(H2O)2] · 2H2O, was synthesized with the reaction of cobalt acetate and 2-picolinic acid as the reactants by solid-solid reaction at room temperature. The composition and structure of the complex were characterized by elemental analysis, infrared spectroscopy, single crystal X-ray diffraction, and thermogravimetry-differential scanning calorimetry (TG-DSC). The crystal structure of the complex belongs to monoclinic system and space group P2(1)/n, with cell parameters of a = 9.8468(7) Å, b = 5.2013(4) Å, c = 14.6041(15) Å, β = 111.745(6)°, V = 747.96(11) Å3, Z = 2, Dc = 1.666 g cm−3, R1 = 0.0297, and wR2 = 0.0831. In the title complex, the Co(II) ion is six-coordinated by two pyridine N atoms and two carboxyl O atoms from two 2-picolinic acid anions, and two O atoms from two H2O molecules, and forming a slightly distorted octahedral geometry. The thermal decomposition processes of the complex under nitrogen include dehydration and pyrolysis of the ligand, and the final residue is cobalt oxalate at about 450°C. PMID:24578654

  9. Binding modes of aromatic ligands to mammalian heme peroxidases with associated functional implications: crystal structures of lactoperoxidase complexes with acetylsalicylic acid, salicylhydroxamic acid, and benzylhydroxamic acid.

    PubMed

    Singh, Amit K; Singh, Nagendra; Sinha, Mau; Bhushan, Asha; Kaur, Punit; Srinivasan, Alagiri; Sharma, Sujata; Singh, Tej P

    2009-07-24

    The binding and structural studies of bovine lactoperoxidase with three aromatic ligands, acetylsalicylic acid (ASA), salicylhydoxamic acid (SHA), and benzylhydroxamic acid (BHA) show that all the three compounds bind to lactoperoxidase at the substrate binding site on the distal heme side. The binding of ASA occurs without perturbing the position of conserved heme water molecule W-1, whereas both SHA and BHA displace it by the hydroxyl group of their hydroxamic acid moieties. The acetyl group carbonyl oxygen atom of ASA forms a hydrogen bond with W-1, which in turn makes three other hydrogen-bonds, one each with heme iron, His-109 N(epsilon2), and Gln-105 N(epsilon2). In contrast, in the complexes of SHA and BHA, the OH group of hydroxamic acid moiety in both complexes interacts with heme iron directly with Fe-OH distances of 3.0 and 3.2A respectively. The OH is also hydrogen bonded to His-109 N(epsilon2) and Gln-105N(epsilon2). The plane of benzene ring of ASA is inclined at 70.7 degrees from the plane of heme moiety, whereas the aromatic planes of SHA and BHA are nearly parallel to the heme plane with inclinations of 15.7 and 6.2 degrees , respectively. The mode of ASA binding provides the information about the mechanism of action of aromatic substrates, whereas the binding characteristics of SHA and BHA indicate the mode of inhibitor binding.

  10. Probing inclusion complexes of cyclodextrins with amino acids by physicochemical approach.

    PubMed

    Roy, Mahendra Nath; Roy, Aditi; Saha, Subhadeep

    2016-10-20

    Formations of host-guest inclusion complexes of two natural amino acids, viz., l-Leucine and l-Isoleucine as guests with α and β-cyclodextrins have been investigated which include diverse applications in modern science such as controlled delivery in the field of pharmaceuticals, food processing etc. Surface tension and conductivity studies establish the formation of inclusion complexes with 1:1 stoichiometry. The interactions of cyclodextrins with amino acids have been supported by density, viscosity, refractive index, hydration and solvation number measurements indicating higher degree of inclusion in case of α-cyclodextrin. l-Leucine interacts more with the hydrophobic cavity of cyclodextrin than its isomer. With the help of stability constant by NMR titration, hydrophobic effect, H-bonds and structural effects the formations of inclusion complexes have been explained. PMID:27474589

  11. Separation of glycols from dilute aqueous solutions via complexation with boronic acids

    SciTech Connect

    Randel, L.A.; King, C.J.

    1991-07-01

    This work examines methods of separating low molecular weight glycols from dilute aqueous solution. Extraction into conventional solvents is generally not economical, since, in the literature reviewed, distribution ratios for the two- to four-carbon glycols are all less than one. Distribution ratios can be increased, however, by incorporating into the organic phase an extracting agent that will complex with the solute of interest. The extracting agent investigated in this work is 3-nitrophenylboronic acid (NPBA). NPBA, a boric acid derivative, reversibly complexes with many glycols. The literature on complexation of borate and related compounds with glycols, including mechanistic data, measurement techniques, and applications to separation processes, provides information valuable for designing experiments with NPBA and is reviewed herein. 88 refs., 15 figs., 24 tabs.

  12. Organic complexant-enhanced mobility of toxic elements in low-level wastes. Quarterly progress report, January-March 1984

    SciTech Connect

    Swanson, J.L.

    1984-06-01

    The results obtained during the third quarter's activities of a project whose objective is to determine how and to what extent organic complexants affect the mobility of toxic elements in subsurface groundwaters at commercial low-level waste disposal sites are described. This project will study nonradioactive toxic elements as well as elements having radioactive isotopes of importance (e.g. /sup 63/Ni, /sup 239/Pu, /sup 241/Am). Organic complexants used in the nuclear industry are being emphasized, but others are being examined. Generic soil components (e.g. hydrous oxides, silica, clays) are being used so that the results will be broadly applicable. Substantiation of the previously indicated sorption of a Pu(IV)-EDTA complex by hydrous ferric oxide (Fe/sub 2/O/sub 3/.xH/sub 2/O) was obtained by comparing the sorption of EDTA in the presence and absence of Pu. Additional data on the sorption of a Ni-EDTA complex by Fe/sub 2/O/sub 3/.xH/sub 2/O were also obtained. Preliminary Ni sorption data were obtained with other complexants (picolinic acid and citric acid), and another generic soil component (TiO/sub 2/). Sorption of a Ni-EDTA complex by an anion exchange resin was observed. Complexed species are thus likely to be present in the resin wastes from certain reactor decontamination solution clean-up operations. An experimental problem that caused some erroneous results for uncomplexed Ni was discovered and corrected. The filters being used to assure good separation of solid and liquid phases were removing Ni from solution, which skewed some earlier results. 11 references, 13 figures, 2 tables.

  13. Effect of environmental factors on the complexation of iron and humic acid.

    PubMed

    Fang, Kai; Yuan, Dongxing; Zhang, Lei; Feng, Lifeng; Chen, Yaojin; Wang, Yuzhou

    2015-01-01

    A method of size exclusion chromatography coupled with ultraviolet spectrophotometry and off-line graphite furnace atomic absorption spectrometry was developed to assess the complexation properties of iron (Fe) and humic acid (HA) in a water environment. The factors affecting the complexation of Fe and HA, such as ionic strength, pH, temperature and UV radiation, were investigated. The Fe-HA complex residence time was also studied. Experimental results showed that pH could influence the deprotonation of HA and hydrolysis of Fe, and thus affected the complexation of Fe and HA. The complexation was greatly disrupted by the presence of NaCl. Temperature had some influence on the complexation. The yield of Fe-HA complexes showed a small decrease at high levels of UV radiation, but the effect of UV radiation on Fe-HA complex formation at natural levels could be neglected. It took about 10 hr for the complexation to reach equilibrium, and the Fe-HA complex residence time was about 20 hr. Complexation of Fe and HA reached a maximum level under the conditions of pH 6, very low ionic strength, in the dark and at a water temperature of about 25°C, for 10 hr. It was suggested that the Fe-HA complex could form mainly in freshwater bodies and reach high levels in the warm season with mild sunlight radiation. With changing environmental parameters, such as at lower temperature in winter or higher pH and ionic strength in an estuary, the concentration of the Fe-HA complex would decrease. PMID:25597677

  14. Homodinuclear lanthanide complexes of phenylthiopropionic acid: synthesis, characterization, cytotoxicity, DNA cleavage, and antimicrobial activity.

    PubMed

    Shiju, C; Arish, D; Kumaresan, S

    2013-03-15

    Lanthanide complexes of La(III), Pr(III), Nd(III), Sm(III), and Ho(III) with phenylthiopropionic acid were synthesized and characterized by elemental analysis, mass, IR, electronic spectra, molar conductance, TGA, and powder XRD. The results show that the lanthanide complexes are homodinuclear in nature. The two lanthanide ions are bridged by eight oxygen atoms from four carboxylate groups. Thermal decomposition profiles are consistent with the proposed formulations. Powder XRD studies show that all the complexes are amorphous in nature. Antimicrobial studies indicate that these complexes exhibit more activity than the ligand itself. The DNA cleavage activity of the ligand and its complexes were assayed on Escherichia coli DNA using gel electrophoresis in the presence of H(2)O(2). The result shows that the Pr(III) and Nd(III) complexes have completely cleaved the DNA. The anticancer activities of the complexes have also been studied towards human cervical cancer cell line (HeLa) and colon cancer cells (HCT116) and it was found that the La(III) and Nd(III) complexes are more active than the corresponding Pr(III), Sm(III), Ho(III) complexes, and the free ligand on both the cancer cells.

  15. Homodinuclear lanthanide complexes of phenylthiopropionic acid: Synthesis, characterization, cytotoxicity, DNA cleavage, and antimicrobial activity

    NASA Astrophysics Data System (ADS)

    Shiju, C.; Arish, D.; Kumaresan, S.

    2013-03-01

    Lanthanide complexes of La(III), Pr(III), Nd(III), Sm(III), and Ho(III) with phenylthiopropionic acid were synthesized and characterized by elemental analysis, mass, IR, electronic spectra, molar conductance, TGA, and powder XRD. The results show that the lanthanide complexes are homodinuclear in nature. The two lanthanide ions are bridged by eight oxygen atoms from four carboxylate groups. Thermal decomposition profiles are consistent with the proposed formulations. Powder XRD studies show that all the complexes are amorphous in nature. Antimicrobial studies indicate that these complexes exhibit more activity than the ligand itself. The DNA cleavage activity of the ligand and its complexes were assayed on Escherichia coli DNA using gel electrophoresis in the presence of H2O2. The result shows that the Pr(III) and Nd(III) complexes have completely cleaved the DNA. The anticancer activities of the complexes have also been studied towards human cervical cancer cell line (HeLa) and colon cancer cells (HCT116) and it was found that the La(III) and Nd(III) complexes are more active than the corresponding Pr(III), Sm(III), Ho(III) complexes, and the free ligand on both the cancer cells.

  16. Oleic acid is a key cytotoxic component of HAMLET-like complexes.

    PubMed

    Permyakov, Sergei E; Knyazeva, Ekaterina L; Khasanova, Leysan M; Fadeev, Roman S; Zhadan, Andrei P; Roche-Hakansson, Hazeline; Håkansson, Anders P; Akatov, Vladimir S; Permyakov, Eugene A

    2012-01-01

    HAMLET is a complex of α-lactalbumin (α-LA) with oleic acid (OA) that selectively kills tumor cells and Streptococcus pneumoniae. To assess the contribution of the proteinaceous component to cytotoxicity of HAMLET, OA complexes with proteins structurally and functionally distinct from α-LA were prepared. Similar to HAMLET, the OA complexes with bovine β-lactoglobulin (bLG) and pike parvalbumin (pPA) (bLG-OA-45 and pPA-OA-45, respectively) induced S. pneumoniae D39 cell death. The activation mechanisms of S. pneumoniae death for these complexes were analogous to those for HAMLET, and the cytotoxicity of the complexes increased with OA content in the preparations. The half-maximal inhibitory concentration for HEp-2 cells linearly decreased with rise in OA content in the preparations, and OA concentration in the preparations causing HEp-2 cell death was close to the cytotoxicity of OA alone. Hence, the cytotoxic action of these complexes against HEp-2 cells is induced mostly by OA. Thermal stabilization of bLG upon association with OA implies that cytotoxicity of bLG-OA-45 complex cannot be ascribed to molten globule-like conformation of the protein component. Overall, the proteinaceous component of HAMLET-like complexes studied is not a prerequisite for their activity; the cytotoxicity of these complexes is mostly due to the action of OA.

  17. Isolated glyoxylic acid-water 1:1 complexes in low temperature argon matrices.

    PubMed

    Lundell, Jan; Olbert-Majkut, Adriana

    2015-02-01

    The 1:1 hydrogen bonded complexes between glyoxylic acid (GA) and water are studied in low temperature argon matrices. Four different complex structures were found in deposited matrices. The lowest energy conformer (T1) of GA was found to form complex, where the water molecule was attached to the opposite side of the intramolecular hydrogen bond in the molecule (T1B). Interestingly, this complex was estimated to be+8.0 kJ mol(-1) higher in energy than the most stable structure (T1A), where the water is inserted into the internal hydrogen bond, and also found in solid argon but in smaller abundance. For the second-lowest energy conformer of GA (T2), the two lowest-energy complex structures were identified, with the most stable complex structure (T2A) also being the most abundant in the matrices. The difference between experiment and computational energetic order of the two complex structures of the same GA conformer is explained by contributions of deformation energy upon complexation and the effect of the environment. The computed BSSE-corrected interaction energies are for the two most stable complexes of the two GA conformers for T1A and T2A -42.11 and -45.03 kJ mol(-1), respectively, at the CCSD(T)/aug-cc-pVTZ//B3LYP/aug-cc-pVTZ level of theory.

  18. EDTA a novel inducer of pisatin, a phytoalexin indicator of the non-host resistance in peas.

    PubMed

    Hadwiger, Lee A; Tanaka, Kiwamu

    2014-12-23

    Pea pod endocarp suppresses the growth of an inappropriate fungus or non-pathogen by generating a "non-host resistance response" that completely suppresses growth of the challenging fungus within 6 h. Most of the components of this resistance response including pisatin production can be elicited by an extensive number of both biotic and abiotic inducers. Thus this phytoalexin serves as an indicator to be used in evaluating the chemical properties of inducers that can initiate the resistance response. Many of the pisatin inducers are reported to interact with DNA and potentially cause DNA damage. Here we propose that EDTA (ethylenediaminetetraacetic acid) is an elicitor to evoke non-host resistance in plants. EDTA is manufactured as a chelating agent, however at low concentration it is a strong elicitor, inducing the phytoalexin pisatin, cellular DNA damage and defense-responsive genes. It is capable of activating complete resistance in peas against a pea pathogen. Since there is also an accompanying fragmentation of pea DNA and alteration in the size of pea nuclei, the potential biochemical insult as a metal chelator may not be its primary action. The potential effects of EDTA on the structure of DNA within pea chromatin may assist the transcription of plant defense genes.

  19. Application of 17% EDTA Enhances Diffusion of (45)Ca-labeled OH(-) and Ca(2+) in Primary Tooth Root Canal.

    PubMed

    Ximenes, Marcos; Cavalcanti Taguchi, Carolina Mayumi; Triches, Thaisa Cezaria; Sartori, Neimar; Pereira Dias, Luis Alberto; de Araujo, Elaine Bortoleti; Cardoso, Mariane

    2016-01-01

    Proper cleaning of the root canal is key to the success of endodontic treatment as it allows more effective diffusion of medication throughout the dentinal tubules. The aim of this in vitro study was to investigate the efficacy of 17% ethylenediaminetetraacetic acid (EDTA) in enhancing diffusion of hydroxyl (OH(-)) and calcium ions (Ca(2+)) throughout the root canal in primary teeth. The canals of 25 primary tooth roots were cleaned with endodontic files and 1% sodium hypochlorite. Three groups (G) were then established: GI, in which final irrigation was performed with 1% sodium hypochlorite; GII, in which 17% EDTA was used; and GIII, in which no irrigation was performed. The roots canals in GI and GII were filled with a calcium hydroxide-based paste labeled with the radioisotope calcium-45. Diffusion of OH(-) was detected with pH strips and Ca(2+) analyzed by measuring radioactivity in counts per min. Group II differed statistically from the other groups in diffusion of OH(-) at 24 hr (p<0.05), but no significant difference among groups was found at the day 7 evaluation; GII also differed statistically from the other groups in diffusion of Ca(2+) at 24 hr (p<0.05). These results suggest that application of 17% EDTA in primary tooth enhances diffusion of OH(-) and Ca(2+). PMID:26961333

  20. Kinetics of formation and dissociation of aquocobalt(III) complexes with some carboxylic acids in acid perchlorate solution.

    PubMed

    Davies, Geoffrey

    2007-06-21

    The rates of formation and dissociation of monocarboxylic complexes of aquocobalt(III) cations with propionic, malonic, and 2-ethylmalonic acids have been measured with the stopped-flow method over a range of concentrations and temperatures in acid perchlorate media at an ionic strength 3.0 M. Although the rate constants for reactions of CoOHaq2+ with neutral ligands cover only a small range, indicating a dissociative mechanism, the associated activation parameters change cooperatively. These variations are discussed in terms of differences in the structure, proton distribution, and rates of water loss in the ion-pair precursors for the different ligands. Similar activation enthalpies of dissociation indicate a common mode of coordination, and the positive activation entropies for dissociation are consistent with a neutral leaving group.

  1. Group 11 complexes with amino acid derivatives: Synthesis and antitumoral studies.

    PubMed

    Ortego, Lourdes; Meireles, Margarida; Kasper, Cornelia; Laguna, Antonio; Villacampa, M Dolores; Gimeno, M Concepción

    2016-03-01

    Gold(I), gold(III), silver(I) and copper(I) complexes with modified amino acid esters and phosphine ligands have been prepared in order to test their cytotoxic activity. Two different phosphine fragments, PPh3 and PPh2py (py=pyridine), have been used. The amino acid esters have been modified by introducing an aromatic amine as pyridine that coordinates metal fragments through the nitrogen atom, giving complexes of the type [M(L)(PR3)](+) or [AuCl3(L)] (L=l-valine-N-(4-pyridylcarbonyl) methyl ester (L1), l-alanine-N-(4-pyridylcarbonyl) methyl ester (L2), l-phenylalanine-N-(4-pyridylcarbonyl) methyl-ester) (L3); M=Au(I), Ag(I), Cu(I), PR3=PPh3, PPh2py). The in vitro cytotoxic activity of metal complexes was tested against four tumor human cell lines and one tumor mouse cell line. A metabolic activity test (3-(4,5-dimethyl-thiazol-2-yl)-2,5-diphenyl tetrazolium bromide, MTT) was used and IC50 values were compared with those obtained for cisplatin. Several complexes displayed significant cytotoxic activities. In order to determine whether antiproliferation and cell death are associated with apoptosis, NIH-3T3 cells were exposed to five selected complexes (Annexin V+ FITC, PI) and analyzed by flow cytometry. These experiments showed that the mechanism by which the complexes inhibit cell proliferation inducing cell death in NIH-3T3 cells is mainly apoptotic.

  2. Effects of blanching, acidification, or addition of EDTA on vitamin C and β-carotene stability during mango purée preparation.

    PubMed

    Guiamba, Isabel R F; Svanberg, Ulf

    2016-09-01

    The impact of acidification with citric acid, addition of EDTA or water blanching at high temperature, and short time (HTST) conducted at 90°C for 4 min, on the retention of vitamin C (L-AA and DHAA) and β-carotene was studied in mango purée 30 min after crushing. HTST blanching prior to matrix disruption into purée resulted in complete inactivation of polyphenol oxidase (PPO) and minor residual activity (8%) of ascorbic acid oxidase (AAO). The retention of total vitamin C was 100% in blanched purées and in purée with EDTA and about 90% in purées at pH 3.9 and 5.0. Acidification, blanching, and addition of EDTA preserved vitamin C mainly as L-AA, while complete conversion into DHAA was observed in purée at pH 5.0. The retention of all-trans-β-carotene was between 65 and 72%, with the highest value in purée with EDTA and the lowest value in purée of blanched mango. The ratio of 13-cis-β-carotene in fresh mango was 8.2 ± 0.5% that increased significantly after blanching and in purée at pH 5.0. PMID:27625774

  3. Effects of blanching, acidification, or addition of EDTA on vitamin C and β-carotene stability during mango purée preparation.

    PubMed

    Guiamba, Isabel R F; Svanberg, Ulf

    2016-09-01

    The impact of acidification with citric acid, addition of EDTA or water blanching at high temperature, and short time (HTST) conducted at 90°C for 4 min, on the retention of vitamin C (L-AA and DHAA) and β-carotene was studied in mango purée 30 min after crushing. HTST blanching prior to matrix disruption into purée resulted in complete inactivation of polyphenol oxidase (PPO) and minor residual activity (8%) of ascorbic acid oxidase (AAO). The retention of total vitamin C was 100% in blanched purées and in purée with EDTA and about 90% in purées at pH 3.9 and 5.0. Acidification, blanching, and addition of EDTA preserved vitamin C mainly as L-AA, while complete conversion into DHAA was observed in purée at pH 5.0. The retention of all-trans-β-carotene was between 65 and 72%, with the highest value in purée with EDTA and the lowest value in purée of blanched mango. The ratio of 13-cis-β-carotene in fresh mango was 8.2 ± 0.5% that increased significantly after blanching and in purée at pH 5.0.

  4. The Ca(2+)-EDTA chelation as standard reaction to validate Isothermal Titration Calorimeter measurements (ITC).

    PubMed

    Ràfols, Clara; Bosch, Elisabeth; Barbas, Rafael; Prohens, Rafel

    2016-07-01

    A study about the suitability of the chelation reaction of Ca(2+)with ethylenediaminetetraacetic acid (EDTA) as a validation standard for Isothermal Titration Calorimeter measurements has been performed exploring the common experimental variables (buffer, pH, ionic strength and temperature). Results obtained in a variety of experimental conditions have been amended according to the side reactions involved in the main process and to the experimental ionic strength and, finally, validated by contrast with the potentiometric reference values. It is demonstrated that the chelation reaction performed in acetate buffer 0.1M and 25°C shows accurate and precise results and it is robust enough to be adopted as a standard calibration process. PMID:27154686

  5. The Ca(2+)-EDTA chelation as standard reaction to validate Isothermal Titration Calorimeter measurements (ITC).

    PubMed

    Ràfols, Clara; Bosch, Elisabeth; Barbas, Rafael; Prohens, Rafel

    2016-07-01

    A study about the suitability of the chelation reaction of Ca(2+)with ethylenediaminetetraacetic acid (EDTA) as a validation standard for Isothermal Titration Calorimeter measurements has been performed exploring the common experimental variables (buffer, pH, ionic strength and temperature). Results obtained in a variety of experimental conditions have been amended according to the side reactions involved in the main process and to the experimental ionic strength and, finally, validated by contrast with the potentiometric reference values. It is demonstrated that the chelation reaction performed in acetate buffer 0.1M and 25°C shows accurate and precise results and it is robust enough to be adopted as a standard calibration process.

  6. Dielectric studies of amylose, amylopectin and amylose-stearic acid complexes.

    PubMed

    Pethrick, Richard A; Song, Ma

    2013-02-15

    The effect of structure creation and moisture content on the dielectric properties of amylose, amylopectin and amylose-stearic acid complexes is presented. Three dielectric features have been identified in these systems. At low temperature, a dipole relaxation process is observed which is assigned to the reorientation of the CH(2)OH group. At ambient temperatures, a thermally activated relaxation is assigned to liberation-local chain motion. In certain systems at high temperatures, a Maxwell Wagner Sillars process is observed associated with the heterogeneous nature of media and is ascribed to the gel structure in the amylose-stearic acid complex. The low temperature relaxation is sensitive to the moisture content, the water molecules being bound to the CH(2)OH groups and the activation energy being reduced as the water content is increased. Comparison of the relaxation observed in amylose and amylopectin indicates that chain branching increases the activation energy and inhibits the local reorientation motion of the chain backbone. The relative magnitude of the relaxation processes and their activation energies are discussed in term of the structure of the polymer backbone, the nature of the complex formed with stearic acid and the extent to which order is created by thermal treatment. This paper gives insight into the changes in amylose mobility accompanying the formation of the various complexes.

  7. Investigating the inclusion properties of aromatic amino acids complexing beta-cyclodextrins in model peptides.

    PubMed

    Caso, Jolanda Valentina; Russo, Luigi; Palmieri, Maddalena; Malgieri, Gaetano; Galdiero, Stefania; Falanga, Annarita; Isernia, Carla; Iacovino, Rosa

    2015-10-01

    Cyclodextrins are commonly used as complexing agents in biological, pharmaceutical, and industrial applications since they have an effect on protein thermal and proteolytic stability, refolding yields, solubility, and taste masking. β-cyclodextrins (β-CD), because of their cavity size are a perfectly suited complexing agent for many common guest moieties. In the case of peptide-cyclodextrin and protein-cyclodextrin host-guest complexes the aromatic amino acids are reported to be the principal responsible of the interaction. For these reasons, we have investigated the inclusion properties of nine designed tripeptides, obtained permuting the position of two L-alanines (Ala, A) with that of one L-tryptophan (Trp, W), L-phenylalanine (Phe, F), or L-tyrosine (Tyr, Y), respectively. Interestingly, the position of the aromatic side-chain in the sequence appears to modulate the β-CD:peptide binding constants, determined via UV-Vis and NMR spectroscopy, which in turn assumes values higher than those reported for the single amino acid. The tripeptides containing a tyrosine showed the highest binding constants, with the central position in the Ac-AYA-NH2 peptide becoming the most favorite for the interaction. A combined NMR and Molecular Docking approach permitted to build detailed complex models, highlighting the stabilizing interactions of the neighboring amino acids backbone atoms with the upper rim of the β-CD.

  8. Sunlight-initiated chemistry of aqueous pyruvic acid: building complexity in the origin of life.

    PubMed

    Griffith, Elizabeth C; Shoemaker, Richard K; Vaida, Veronica

    2013-10-01

    Coupling chemical reactions to an energy source is a necessary step in the origin of life. Here, we utilize UV photons provided by a simulated sun to activate aqueous pyruvic acid and subsequently prompt chemical reactions mimicking some of the functions of modern metabolism. Pyruvic acid is interesting in a prebiotic context due to its prevalence in modern metabolism and its abiotic availability on early Earth. Here, pyruvic acid (CH3COCOOH, a C3 molecule) photochemically reacts to produce more complex molecules containing four or more carbon atoms. Acetoin (CH3CHOHCOCH3), a C4 molecule and a modern bacterial metabolite, is produced in this chemistry as well as lactic acid (CH3CHOHCOOH), a molecule which, when coupled with other abiotic chemical reaction pathways, can provide a regeneration pathway for pyruvic acid. This chemistry is discussed in the context of plausible environments on early Earth such as near the ocean surface and atmospheric aerosol particles. These environments allow for combination and exchange of reactants and products of other reaction environments (such as shallow hydrothermal vents). The result could be a contribution to the steady increase in chemical complexity requisite in the origin of life.

  9. Sunlight-initiated Chemistry of Aqueous Pyruvic Acid: Building Complexity in the Origin of Life

    NASA Astrophysics Data System (ADS)

    Griffith, Elizabeth C.; Shoemaker, Richard K.; Vaida, Veronica

    2013-10-01

    Coupling chemical reactions to an energy source is a necessary step in the origin of life. Here, we utilize UV photons provided by a simulated sun to activate aqueous pyruvic acid and subsequently prompt chemical reactions mimicking some of the functions of modern metabolism. Pyruvic acid is interesting in a prebiotic context due to its prevalence in modern metabolism and its abiotic availability on early Earth. Here, pyruvic acid (CH3COCOOH, a C3 molecule) photochemically reacts to produce more complex molecules containing four or more carbon atoms. Acetoin (CH3CHOHCOCH3), a C4 molecule and a modern bacterial metabolite, is produced in this chemistry as well as lactic acid (CH3CHOHCOOH), a molecule which, when coupled with other abiotic chemical reaction pathways, can provide a regeneration pathway for pyruvic acid. This chemistry is discussed in the context of plausible environments on early Earth such as near the ocean surface and atmospheric aerosol particles. These environments allow for combination and exchange of reactants and products of other reaction environments (such as shallow hydrothermal vents). The result could be a contribution to the steady increase in chemical complexity requisite in the origin of life.

  10. Efficient in vivo gene transfection by stable DNA/PEI complexes coated by hyaluronic acid.

    PubMed

    Ito, Tomoko; Iida-Tanaka, Naoko; Koyama, Yoshiyuki

    2008-05-01

    Plasmid DNA was mixed with polyethyleneimine (PEI) and hyaluronic acid (HA) to afford ternary complexes with negative surface charge regardless of the mixing order. They showed reduced non-specific interactions with blood components. When DNA and PEI were mixed at a high concentration such as that used in in vivo experiments, they soon aggregated, and large particles were formed. On the other hand, pre-addition of HA to DNA prior to PEI effectively diminished the aggregation, and 10% (in volume) of the complexes remained as small particles with a diameter below 80 nm. Those negatively charged small ternary complexes induced a much stronger extra-gene expression in tumor than binary DNA/PEI complex after intratumoral or intravenous injection into the mice bearing B16 cells. PMID:18446606

  11. Synthesis and amino acids complexation of tripodal hexasubstituted benzene chiral receptors

    NASA Astrophysics Data System (ADS)

    Choksakulporn, Saowanaporn; Punkvang, Auradee; Sritana-anant, Yongsak

    2015-02-01

    The parent 1,3,5-triacetyl-2,4,6-trihydroxybenzene was prepared in up to 91% yield using a one-pot, one step reaction catalyzed by aluminum chloride. Its alkylations with 1,5-dibromopentane generated a symmetric tripodal hexasubstituted benzene precursor in the alternated conformer predicted by a theoretical calculation. Subsequent substitutions and reductions provided the corresponding tris-amine in 59% yield. Aminations of the tripodal precursor with (R)-(+)-1-phenylethylamine obtained a chiral tris-amine ligand in 44% yield. 1H NMR titrations of this ligand with each of three L-amino acid derivatives as guest molecules confirmed the presence of their complexes, in which the complex with alanine derivative displayed the strongest interactions with the ligand. Job plots suggested that all complexes composed of 1:2 ratios of the ligand and these guests. Theoretical calculations additionally revealed the structures and the associated binding parameters of the complexes.

  12. Fractionation of SWNT/nucleic acid complexes by agarose gel electrophoresis

    NASA Astrophysics Data System (ADS)

    Vetcher, Alexandre A.; Srinivasan, Srimeenakshi; Vetcher, Ivan A.; Abramov, Semen M.; Kozlov, Mikhail; Baughman, Ray H.; Levene, Stephen D.

    2006-08-01

    We show that aqueous dispersions of single-walled carbon nanotubes (SWNTs), prepared with the aid of nucleic acids (NAs) such as RNA or DNA, can be separated into fractions using agarose gel electrophoresis. In a DC electric field, SWNT/NA complexes migrate in the gel in the direction of positive potential to form well-defined bands. Raman spectroscopy as a function of band position shows that nanotubes having different spectroscopic properties possess different electrophoretic mobilities. The migration patterns for SWNT/RNA and SWNT/DNA complexes differ. Parallel elution of the SWNT/NA complexes from the gel during electrophoresis and subsequent characterization by AFM reveals differences in nanotube diameter, length and curvature. The results suggest that fractionation of nanotubes can be achieved by this procedure. We discuss factors affecting the mobility of the nanotube complexes and propose analytical applications of this technique.

  13. Complexation of amidated pectin with poly(itaconic acid) as a polycarboxylic polymer model compound.

    PubMed

    Nesic, Aleksandra R; Trifunovic, Snezana S; Grujic, Aleksandar S; Velickovic, Sava J; Antonovic, Dusan G

    2011-11-01

    Complexes based on amidated pectin (AP) and poly(itaconic acid) (PIA) were prepared by casting films from solutions of AP and PIA in different ratios with the pectin amount ranging from 10% to 90% by mass. The complexes were investigated by elemental analysis, Fourier-transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), and thermogravimetry (TG). In all investigated ratios of AP/PIA glassy transparent films with a uniform structure were obtained. The results of elemental analysis confirmed the composition of the complexes, and FTIR spectroscopy has shown carboxylic and amide peak shifting, indicating complex formation between AP and PIA. Comparison of thermograms of AP/PIA films with different ratios of AP indicated that the increase of the amount of AP increases the thermal stability of the films by retarding the onset of the main degradation processes. PMID:21943549

  14. Determination of thermodynamic values of acidic dissociation constants and complexation constants of profens and their utilization for optimization of separation conditions by Simul 5 Complex.

    PubMed

    Riesová, Martina; Svobodová, Jana; Ušelová, Kateřina; Tošner, Zdeněk; Zusková, Iva; Gaš, Bohuslav

    2014-10-17

    In this paper we determine acid dissociation constants, limiting ionic mobilities, complexation constants with β-cyclodextrin or heptakis(2,3,6-tri-O-methyl)-β-cyclodextrin, and mobilities of resulting complexes of profens, using capillary zone electrophoresis and affinity capillary electrophoresis. Complexation parameters are determined for both neutral and fully charged forms of profens and further corrected for actual ionic strength and variable viscosity in order to obtain thermodynamic values of complexation constants. The accuracy of obtained complexation parameters is verified by multidimensional nonlinear regression of affinity capillary electrophoretic data, which provides the acid dissociation and complexation parameters within one set of measurements, and by NMR technique. A good agreement among all discussed methods was obtained. Determined complexation parameters were used as input parameters for simulations of electrophoretic separation of profens by Simul 5 Complex. An excellent agreement of experimental and simulated results was achieved in terms of positions, shapes, and amplitudes of analyte peaks, confirming the applicability of Simul 5 Complex to complex systems, and accuracy of obtained physical-chemical constants. Simultaneously, we were able to demonstrate the influence of electromigration dispersion on the separation efficiency, which is not possible using the common theoretical approaches, and predict the electromigration order reversals of profen peaks. We have shown that determined acid dissociation and complexation parameters in combination with tool Simul 5 Complex software can be used for optimization of separation conditions in capillary electrophoresis.

  15. Influence of FeEDDS, FeEDTA, FeDTPA, FeEDDHA, and FeSO4 on Marigold Growth and Nutrition, and Substrate and Runoff Chemistry

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Objectives of the study were to determine effects of Fe source on plant growth, plant nutrition, substrate chemistry and runoff chemistry. Iron source (FS) treatments consisted of Fe-aminopolycarboxylic acid (APCA) complexones iron ethylenediaminetetraacetic acid (FeEDTA), iron [S, S']-ethylenediam...

  16. Labile sulfide and sulfite in phytochelatin complexes

    SciTech Connect

    Eannetta, N.T.; Steffens, J.C. )

    1989-04-01

    Heavy metals such as cadmium induce tomato cell cultures to synthesize the metal binding polypeptides ({gamma}-Glu-Cys){sub 3} and ({gamma}-Glu-Cys){sub 4}-Gly (phytochelatins). Tomato cells selected for growth on normally lethal concentrations of CdCl{sub 2} synthesize higher quantities of these polypeptides. Cd{sup r} cells are not cross-resistant to other heavy metals, and recent work suggests that metal detoxification by these peptides may be Cd-specific. The occurrence of labile sulfur as a component of the metal complex raises questions concerning possible functions of phytochelatins besides that of Cd binding. The presence of acid-labile sulfide ion in phytochelatin complexes has been reported by several groups. We report the additional finding that labile sulfite is also present in these complexes and in higher amounts than sulfide. Sulfide and sulfite are both released from the metal binding complex by acidification or by treatment with EDTA.

  17. Manganese salen complexes with acid-base catalytic auxiliary: functional mimetics of catalase.

    PubMed

    Noritake, Yukinobu; Umezawa, Naoki; Kato, Nobuki; Higuchi, Tsunehiko

    2013-04-01

    Antioxidant therapies have been considered for a wide variety of disorders associated with oxidative stress, and synthetic catalytic scavengers of reactive oxygen species would be clinically superior to stoichiometric ones. Among them, salen-manganese complexes (Mn(Salen)) seem promising, because they exhibit dual functions, i.e. superoxide dismutase- and catalase-mimetic activities. We have been developing enzyme-mimetic Mn(Salen) complexes bearing a functional group that enhances their catalytic activity. Here, we describe the design and synthesis of novel Mn(Salen) complexes with general acid-base catalytic functionality, inspired by the reaction mechanism of catalase. As expected, these Mn(Salen) complexes showed superior catalase-like activity and selectivity, while retaining moderate SOD-like activity. An unsubstituted pyridyl group worked well as a functionality to promote catalase-like activity. The introduced functionality did not alter the redox potential suggesting that the auxiliary-modified complex acted as an acid-base catalyst analogous to catalase. We believe that our approach provides a new design principle for sophisticated catalyst design. Further, the compounds described here appear to be good candidates for use in antioxidant therapy.

  18. Molecular mechanism of the assembly of an acid-sensing receptor ion channel complex.

    PubMed

    Yu, Yong; Ulbrich, Maximilian H; Li, Ming-Hui; Dobbins, Scott; Zhang, Wei K; Tong, Liang; Isacoff, Ehud Y; Yang, Jian

    2012-01-01

    Polycystic kidney disease (PKD) family proteins associate with transient receptor potential (TRP) channel family proteins to form functionally important complexes. PKD proteins differ from known ion channel-forming proteins and are generally thought to act as membrane receptors. Here we find that PKD1L3, a PKD protein, functions as a channel-forming subunit in an acid-sensing heteromeric complex formed by PKD1L3 and TRPP3, a TRP channel protein. Single amino-acid mutations in the putative pore region of both proteins alter the channel's ion selectivity. The PKD1L3/TRPP3 complex in the plasma membrane of live cells contains one PKD1L3 and three TRPP3. A TRPP3 C-terminal coiled-coil domain forms a trimer in solution and in crystal, and has a crucial role in the assembly and surface expression of the PKD1L3/TRPP3 complex. These results demonstrate that PKD subunits constitute a new class of channel-forming proteins, enriching our understanding of the function of PKD proteins and PKD/TRPP complexes. PMID:23212381

  19. Amino acids and their Cu complexes covalently grafted onto a polystyrene resin A vibrational spectroscopic study

    NASA Astrophysics Data System (ADS)

    Korbély, B.; Kiss, J. T.; Hernadi, K.; Pálinkó, I.

    2007-05-01

    Immobilised Cu(II)- L-tyrosine methylester and Cu(II)-BOC- L-histidine complexes were prepared through covalently grafting the amino acid ligands onto chlorine-functionalised polystyrene. The steps of the syntheses were followed by IR spectroscopy. The ligand to central ion ratio was four in both anchored complexes, and the most probable coordination sites were the carboxylic, the amino and the phenolic OH groups and the imidazole nitrogens for the tyrosine methylester and the BOC- L-histidine, respectively.

  20. Quantum-chemical studies of dimethylformamide 1 : 1 complexes with phosphoric acid

    NASA Astrophysics Data System (ADS)

    Krest'yaninov, M. A.; Kiselev, M. G.; Safonova, L. P.

    2012-12-01

    The structures of two phosphoric acid conformations, dimethylformamide (DMFA), four protonated DMFA forms, and nine DMFA-H3PO4 complexes in which the proton acceptor is a oxygen or nitrogen atom of the DMFA molecule are optimized by DFT/B3LYP using the 6-31++G( d, p) basis set. The structural changes in DMFA that occur upon its protonation are discussed. The stabilization energy and transferred charge values upon the formation of a hydrogen bond are calculated for all of the studied complexes by means of NBO analysis. The potential energy surface is scanned to study the possibility of proton transfer.

  1. Photophysics of Fe(III) complexes with fluorosalicylic acid isomers in aqueous solutions

    NASA Astrophysics Data System (ADS)

    Pozdnyakov, Ivan P.; Melnikov, Alexey A.; Šípoš, Rastislav; Chekalin, Sergey V.; Šima, Jozef

    2016-09-01

    Transient absorption spectroscopy is used to study photophysical processes of 1:1 Fe(III) complexes with all four fluorosalicylic acid isomers (Fe-FSAs) in aqueous solutions. Excited states of Fe-FSAs decay to the ground electronic state with two time constants. The faster process is interpreted as internal conversion to the vibrationally hot electronic ground state and the slower one - as a combination of vibrational cooling and solvation of the ground state. The results obtained for Fe-FSAs and other previously investigated Fe(III) salicylato compounds allow us to reveal the main cause of photochemical stability of the complexes upon charge transfer band excitation.

  2. Sorption of arsenate and arsenite anions by iron(III)-poly(hydroxamic acid) complex.

    PubMed

    Haron, M J; Wan Yunus, W M; Yong, N L; Tokunaga, S

    1999-12-01

    Iron(III)-poly(hydroxamic acid) resin complex has been studied for its sorption abilities with respect to arsenate and arsenite anions from an aqueous solution. The complex was found effective in removing the arsenate anion in the pH range of 2.0 to 5.5. The maximum sorption capacity was found to be 1.15 mmol/g. The sorption selectivity showed that arsenate sorption was not affected by chloride, nitrate and sulphate. The resin was tested and found effective for removal of arsenic ions from industrial wastewater samples.

  3. Spectroscopy of charge transfer complexes of four amino acids as organic two-dimensional conductors

    NASA Astrophysics Data System (ADS)

    Padhiyar, Ashvin; Patel, A. J.; Oza, A. T.

    2007-12-01

    It is found in this study that four amino acids, namely asparagine, arginine, histidine and glutamine form two-dimensional conducting systems which are charge transfer complexes (CTCs) with organic acceptors like TCNQ, TCNE, chloranil, DDQ, TNF and iodine. It is verified using optical absorption edges that these are 2d conductors like transition metal dichalcogenides obeying absorption functions different from 1d and 3d conductors. This 2d nature is related to the network of intermolecular H-bonding in these complexes, which leads to a global H-bonded network resulting in the absence of local deformation due to the relaxation of strain.

  4. A Complex Prime Numerical Representation of Amino Acids for Protein Function Comparison.

    PubMed

    Chen, Duo; Wang, Jiasong; Yan, Ming; Bao, Forrest Sheng

    2016-08-01

    Computationally assessing the functional similarity between proteins is an important task of bioinformatics research. It can help molecular biologists transfer knowledge on certain proteins to others and hence reduce the amount of tedious and costly benchwork. Representation of amino acids, the building blocks of proteins, plays an important role in achieving this goal. Compared with symbolic representation, representing amino acids numerically can expand our ability to analyze proteins, including comparing the functional similarity of them. Among the state-of-the-art methods, electro-ion interaction pseudopotential (EIIP) is widely adopted for the numerical representation of amino acids. However, it could suffer from degeneracy that two different amino acid sequences have the same numerical representation, due to the design of EIIP. In light of this challenge, we propose a complex prime numerical representation (CPNR) of amino acids, inspired by the similarity between a pattern among prime numbers and the number of codons of amino acids. To empirically assess the effectiveness of the proposed method, we compare CPNR against EIIP. Experimental results demonstrate that the proposed method CPNR always achieves better performance than EIIP. We also develop a framework to combine the advantages of CPNR and EIIP, which enables us to improve the performance and study the unique characteristics of different representations. PMID:27249328

  5. Preparation and structural elucidation of (-)-tetrahydroberberine-(+)-2,3-di( p-toluyl) tartaric acid complex

    NASA Astrophysics Data System (ADS)

    Gao, Jin-Ming; Liu, Wei-Tao; Li, Man-Lin; Liu, Han-Wei; Zhang, Xing-Chang; Li, Zong-Xiao

    2008-12-01

    A new (2:1) complex of (-)-13a S-tetrahydroberberine [(-)-13a S-THB] with (+)-2,3-di( p-toluyl) tartaric acid (DTTA), i.e. 5,8,13,13a-tetrahydro-9,10-dimethoxy-2,3-methylenedioxy- 6H dibenzo[a,g] quinolizine·2,3-di( p-toluyl) tartaric acid [2C 20H 20NO 4·C 20H 18O 8], as well as its optical active component (-)-THB, has been obtained from the resolution process of (±)-THB in methanol. The structures of this complex and an enantiomer (-)-13a S-THB have been characterized by CD, IR and NMR spectroscopy as well as by X-ray single crystal diffraction.

  6. Production of complex nucleic acid libraries using highly parallel in situ oligonucleotide synthesis.

    PubMed

    Cleary, Michele A; Kilian, Kristopher; Wang, Yanqun; Bradshaw, Jeff; Cavet, Guy; Ge, Wei; Kulkarni, Amit; Paddison, Patrick J; Chang, Kenneth; Sheth, Nihar; Leproust, Eric; Coffey, Ernest M; Burchard, Julja; McCombie, W Richard; Linsley, Peter; Hannon, Gregory J

    2004-12-01

    Generation of complex libraries of defined nucleic acid sequences can greatly aid the functional analysis of protein and gene function. Previously, such studies relied either on individually synthesized oligonucleotides or on cellular nucleic acids as the starting material. As each method has disadvantages, we have developed a rapid and cost-effective alternative for construction of small-fragment DNA libraries of defined sequences. This approach uses in situ microarray DNA synthesis for generation of complex oligonucleotide populations. These populations can be recovered and either used directly or immortalized by cloning. From a single microarray, a library containing thousands of unique sequences can be generated. As an example of the potential applications of this technology, we have tested the approach for the production of plasmids encoding short hairpin RNAs (shRNAs) targeting numerous human and mouse genes. We achieved high-fidelity clone retrieval with a uniform representation of intended library sequences. PMID:15782200

  7. Heterobimetallic dinuclear lanthanide alkoxide complexes as acid-base difunctional catalysts for transesterification.

    PubMed

    Zeng, Ruijie; Sheng, Hongting; Zhang, Yongcang; Feng, Yan; Chen, Zhi; Wang, Junfeng; Chen, Man; Zhu, Manzhou; Guo, Qingxiang

    2014-10-01

    A practical lanthanide(III)-catalyzed transesterification of carboxylic esters, weakly reactive carbonates, and much less-reactive ethyl silicate with primary and secondary alcohols was developed. Heterobimetallic dinuclear lanthanide alkoxide complexes [Ln2Na8{(OCH2CH2NMe2)}12(OH)2] (Ln = Nd (I), Sm (II), and Yb (III)) were used as highly active catalysts for this reaction. The mild reaction conditions enabled the transesterification of various substrates to proceed in good to high yield. Efficient activation of transesterification may be endowed by the above complexes as cooperative acid-base difunctional catalysts, which is proposed to be responsible for the higher reactivity in comparison with simple acid/base catalysts.

  8. DNA/polyethyleneimine/hyaluronic acid small complex particles and tumor suppression in mice.

    PubMed

    Ito, Tomoko; Yoshihara, Chieko; Hamada, Katsuyuki; Koyama, Yoshiyuki

    2010-04-01

    The highest barriers for non-viral vectors to an efficient in vivo gene transfection would be (1) non-specific interaction with biological molecules, and (2) large size of the DNA complex particles. Protective coating of the DNA/polyethyleneimine (PEI) complexes by hyaluronic acid (HA) effectively diminished the adverse interactions with biological molecules. Here we found HA also protected the DNA/PEI complexes against aggregation and inactivation through lyophilization-and-rehydration procedures. It allows us to prepare the concentrated very small DNA complex particles (<70 nm) suspension by preparing the complexes at highly diluted conditions, followed by lyophilized-and-rehydrated to a small volume. In vivo gene expression efficiency of the small complex was examined with mice subcutaneously inoculated with B16 melanoma cells. These formulations showed high reporter-gene expression level in tumor after intravenous injection into tumor-bearing mice. Small complex was then made of the plasmid encoding GM-CSF gene, and injected into the mice bearing subcutaneous solid B16 tumor. After intravenous injection, it induced apparent tumor growth suppression in 50% of the mice. Notably, significant therapeutic effect was detected in the mice that received intratumoral injection, and 75% of the mice were completely cured with disappearance of tumor. PMID:20047759

  9. Reversible Oxygenation of 2,4-Diaminobutanoic Acid-Co(II) Complexes

    PubMed Central

    Li, Hui; Yue, Fan; Wen, Hongmei

    2016-01-01

    This paper introduces the structural characterization and studies on reversible oxygenation behavior of a new oxygen carrier Co(II)-2,4-diaminobutanoic acid (DABA) complex in aqueous solution. The composition of the oxygenated complex was determined by gas volumetric method, molar ratio method, and mass spectrometry, and the formula of the oxygenated complex was determined to be [Co(DABA)2O2]. In aqueous solution, the complex can continuously uptake and release dioxygen and exhibit excellent reversibility of oxygenation and deoxygenation ability. This complex can maintain 50% of its original oxygenation capacity after 30 cycles in 24 h and retain 5% of the original oxygenation capacity after more than 260 cycles after 72 h. When a ligand analogue was linked to histidine (His), the new complex exhibited as excellent reversible oxygenation property as His-Co(II) complex. Insight into the relationship between structural detail and oxygenation properties will provide valuable suggestion for a new family of oxygen carriers.

  10. Antitumor activity of a 2-pyridinecarboxaldehyde 2-pyridinecarboxylic acid hydrazone copper complex and the related mechanism.

    PubMed

    Yang, Yingli; Huang, Tengfei; Zhou, Sufeng; Fu, Yun; Liu, Youxun; Yuan, Yanbin; Zhang, Qiongqing; Li, Shaoshan; Li, Changzheng

    2015-09-01

    In the present study, 2-pyridinecarboxaldehyde 2-pyridinecarboxylic acid hydrazone (PPAH) was prepared and its antitumor activity was evaluated. The inhibition of proliferation of PPAH against the HepG2 and HCT-116 cell lines was less effective, yet in the presence of copper ions, the mixture demonstrated excellent antitumor activity (IC50 at 2.75±0.30 µM for the HepG2 cell line, and 1.90±0.20 µM for the HCT-116 cell line, respectively) and the new active species was confirmed to be a PPAH copper complex with a 1:1 ratio by spectral analysis. The excellent antitumor activity of the copper complex prompted us to investigate the underlying mechanism. RT-PCR was performed to detect the changes in the expression of apoptotic genes induced by PPAH and its copper complex. However, no changes were observed when the cells were treated by the agents for 24 or 48 h, indicating that ROS were unlikely involved. Cell cycle analysis showed that both PPAH and its copper complex led to S phase arrest of the cells. The sDNA relaxation assay revealed that the PPAH-copper complex displayed dual topoisomerase inhibition for type I and II. The data suggest that the inhibition of proliferation exhibited by the PPAH copper complex may stem from its dual topoisomerase inhibition, which is rarely observed for a metal complex.

  11. Reversible Oxygenation of 2,4-Diaminobutanoic Acid-Co(II) Complexes.

    PubMed

    Cheng, Xiang; Huang, Yan; Li, Hui; Yue, Fan; Wen, Hongmei; Wang, Jide

    2016-01-01

    This paper introduces the structural characterization and studies on reversible oxygenation behavior of a new oxygen carrier Co(II)-2,4-diaminobutanoic acid (DABA) complex in aqueous solution. The composition of the oxygenated complex was determined by gas volumetric method, molar ratio method, and mass spectrometry, and the formula of the oxygenated complex was determined to be [Co(DABA)2O2]. In aqueous solution, the complex can continuously uptake and release dioxygen and exhibit excellent reversibility of oxygenation and deoxygenation ability. This complex can maintain 50% of its original oxygenation capacity after 30 cycles in 24 h and retain 5% of the original oxygenation capacity after more than 260 cycles after 72 h. When a ligand analogue was linked to histidine (His), the new complex exhibited as excellent reversible oxygenation property as His-Co(II) complex. Insight into the relationship between structural detail and oxygenation properties will provide valuable suggestion for a new family of oxygen carriers. PMID:27648004

  12. Reversible Oxygenation of 2,4-Diaminobutanoic Acid-Co(II) Complexes

    PubMed Central

    Li, Hui; Yue, Fan; Wen, Hongmei

    2016-01-01

    This paper introduces the structural characterization and studies on reversible oxygenation behavior of a new oxygen carrier Co(II)-2,4-diaminobutanoic acid (DABA) complex in aqueous solution. The composition of the oxygenated complex was determined by gas volumetric method, molar ratio method, and mass spectrometry, and the formula of the oxygenated complex was determined to be [Co(DABA)2O2]. In aqueous solution, the complex can continuously uptake and release dioxygen and exhibit excellent reversibility of oxygenation and deoxygenation ability. This complex can maintain 50% of its original oxygenation capacity after 30 cycles in 24 h and retain 5% of the original oxygenation capacity after more than 260 cycles after 72 h. When a ligand analogue was linked to histidine (His), the new complex exhibited as excellent reversible oxygenation property as His-Co(II) complex. Insight into the relationship between structural detail and oxygenation properties will provide valuable suggestion for a new family of oxygen carriers. PMID:27648004

  13. Thermodynamic, spectroscopic, and computational studies of lanthanide complexation with Diethylenetriaminepentaacetic acide: temperature effect and coordination modes

    SciTech Connect

    Guoxin Tian; Leigh R. Martin; Zhiyong Zhang; Linfeng Rao

    2011-04-01

    Stability constants of two DTPA (diethylenetriaminepentaacetic acid) complexes with lanthanides (ML2- and MHL-, where M stands for Nd and Eu and L stands for diethylenetriaminepentaacetate) at 10, 25, 40, 55, and 70 degrees C were determined by potentiometry, absorption spectrophotometry, and luminescence spectroscopy. The enthalpies of complexation at 25 degrees C were determined by microcalorimetry. Thermodynamic data show that the complexation of Nd3þ and Eu3þ with DTPA is weakened at higher temperatures, a 10-fold decrease in the stability constants of ML2- and MHL- as the temperature is increased from 10 to 70 degrees C. The effect of temperature is consistent with the exothermic enthalpy of complexation directly measured by microcalorimetry. Results by luminescence spectroscopy and density functional theory (DFT) calculations suggest that DTPA is octa-dentate in both the EuL2- and EuHL- complexes and, for the first time, the coordination mode in the EuHL- complex was clarified by integration of the experimental data and DFT calculations. In the EuHL- complex, the Eu is coordinated by an octa-dentate H(DTPA) ligand and a water molecule, and the protonation occurs on the oxygen of a carboxylate group.

  14. Interconversion of CO2 and formic acid by bio-inspired Ir complexes with pendent bases.

    PubMed

    Fujita, Etsuko; Muckerman, James T; Himeda, Yuichiro

    2013-01-01

    Recent investigations of the interconversion of CO2 and formic acid using Ru, Ir and Fe complexes are summarized in this review. During the past several years, both the reaction rates and catalyst stabilities have been significantly improved. Remarkably, the interconversion (i.e., reversibility) has also been achieved under mild conditions in environmentally benign water solvent by slightly changing the pH of the aqueous solution. Only a few catalysts seem to reflect a bio-inspired design such as the use of proton responsive ligands, ligands with pendent bases or acids for a second-coordination-sphere interaction, electroresponsive ligands, and/or ligands having a hydrogen bonding function with a solvent molecule or an added reagent. The most successful of these is an iridium dinuclear complex catalyst that at least has the first three of these characteristics associated with its bridging ligand. By utilizing an acid/base equilibrium for proton removal, the ligand becomes a strong electron donor, resulting in Ir(I) character with a vacant coordination site at each metal center in slightly basic solution. Complemented by DFT calculations, kinetic studies of the rates of formate production using a related family of Ir complexes with and without such functions on the ligand reveal that the rate-determining step for the CO2 hydrogenation is likely to be H2 addition through heterolytic cleavage involving a "proton relay" through the pendent base. The dehydrogenation of formic acid, owing to the proton responsive ligands changing character under slightly acidic pH conditions, is likely to occur by a mechanism with a different rate-determining step. This article is part of a Special Issue entitled: Metals in Bioenergetics and Biomimetics Systems. PMID:23174332

  15. Hydration effect on proton transfer in melamine-cyanuric acid complex.

    PubMed

    Yan, Shihai; Kang, Baotao; Lee, Jin Yong; Sun, Lixiang

    2016-07-01

    Self-assembly of melamine-cyanuric acid (MC) leads to urinary tract calculi and renal failure. The hydration effects on molecular geometry, the IR spectra, the frontier molecular orbital, the energy barrier of proton transfer (PT), as well as the stability of MC were explored by density functional theory (DFT) calculations. The intramolecular PT breaks the big π-conjugated ring of melamine or converts the p-π conjugation (:N-C'=O) to π-π conjugation (O=C-N=C') of cyanuric acid. The intermolecular PT varies the coupling between melamine and cyanuric acid from pure hydrogen bonds (Na…HNd and NH…O) to the cooperation of cation…anion electrostatic interaction (NaH(+)…Nd (-)) and two NH…O hydrogen bonds. Distinct IR spectra shifts occur for Na…HNd stretching mode upon PT, i.e., blue-shift upon intramolecular PT and red-shift upon intermolecular PT. It is expected that the PT would inhibit the generation of rosette-like structure or one-dimensional tape conformer for the MC complexes. Hydration obviously effects the local geometric structure around the water binding site, as well as the IR spectra of NH…O and N…HN hydrogen bonds. Hydration decreases the int