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Sample records for acid edta complex

  1. 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.

  2. 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)

  3. 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. PMID:25476391

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

    NASA Astrophysics Data System (ADS)

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

    1995-12-01

    The sorption of Co(II)EDTA 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 60Co(II)- 14C/EDTA added as the preformed 1:1, Co(II)EDTA 2- complex. Sorption experiments were performed with fixed concentrations of Co(II)EDTA 2- (10 -5 mol/L) and variable pH (all materials), and fixed pH (4.4) with variable Co(II)EDTA 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 (goethite only) mol/L Ca(Cl0 4) 2. Aqueous Fe 3+aq) and Al'(a'q) were measured at the time of the sorption determination. On goethite, Co(II) EDTA 2- exhibited anion-like sorption, increasing with decreasing pH. Increasing electrolyte concentration decreased sorption, indicating a weak, ion-pair type surface complex. Below pH6, however, the sorption chemistry of Co 2+ and EDTA 4- became complex and disparate as a result of Co(II)EDTA 2--dissociation. dissociation was driven by exchange with Fe 3+(aq). A nonelectrostatic surface complexation model that explicitly considered the Fe 3+-Co(II)EDTA 2- exchange reaction was able to adequately describe the sorption data using surface complexes with Co(II)EDTA 2-, FeEDTA -, and Co 2+. The subsurface sediments contained variable amounts of grain-coating iron and aluminum oxides and layer silicates and their substrate mineralogy was dominated by quartz and plagioclase with some mica. 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 goethite, hematite, and feroxyhite. Aluminum oxides were also present. The sorption behavior of Co(II) EDTA 2- on the subsurface sediments was much weaker than, but analogous in behavior to

  5. 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.

  6. 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.

  7. 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

  8. 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

  9. 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…

  10. 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.

  11. EDTA and mixed-ligand complexes of tetravalent and trivalent plutonium.

    PubMed

    Boukhalfa, Hakim; Reilly, Sean D; Smith, Wayne H; Neu, Mary P

    2004-09-20

    EDTA forms stable complexes with plutonium that are integral to nuclear material processing, radionuclide decontamination, and the potentially enhanced transport of environmental contamination. To characterize the aqueous Pu(4+/3+)EDTA species formed under the wide range of conditions of these processes, potentiometry, spectrophotometry, and cyclic voltammetry were used to measure solution equilibria. The results reveal new EDTA and mixed-ligand complexes and provide more accurate stability constants for previously identified species. In acidic solution (pH < 4) and at 1:1 ligand to metal ratio, PuY (where Y4- is the tetra-anion of EDTA) is the predominant species, with an overall formation constant of log beta110 = 26.44. At higher pH, the hydrolysis species, PuY(OH)- and PuY(OH)(2)2-, form with the corresponding overall stability constants log beta(11 - 1) = 21.95 and log beta(11 - 2) = 15.29. The redox potential of the complex PuY at pH = 2.3 was determined to be E(1/2) = 342 mV. The correlation between redox potential, pH, and the protonation state of PuY- was derived to estimate the redox potential of the Pu(4+/3+)Y complex as a function of pH. Under conditions of neutral pH and excess EDTA relative to Pu4+, PuY(2)4- forms with an overall formation constant of log beta120 = 35.39. In the presence of ancillary ligands, mixed-ligand complexes form, as exemplified by the citrate and carbonate complexes PuY(citrate)3- (log beta1101 = 33.45) and PuY(carbonate)2- (log beta1101 = 35.51). Cyclic voltammetry shows irreversible electrochemical behavior for these coordinatively saturated Pu4+ complexes: The reduction wave is shifted approximately -400 mV from the reduction wave of the complex PuY, while the oxidation wave is invariant. PMID:15360230

  12. Biodegradation of Metal-EDTA Complexes by an Enriched Microbial Population

    PubMed Central

    Thomas, Russell A. P.; Lawlor, Kirsten; Bailey, Mark; Macaskie, Lynne E.

    1998-01-01

    A mixed culture utilizing EDTA as the sole carbon source was isolated from a mixed inoculum of water from the River Mersey (United Kingdom) and sludge from an industrial effluent treatment plant. Fourteen component organisms were isolated from the culture, including representatives of the genera Methylobacterium, Variovorax, Enterobacter, Aureobacterium, and Bacillus. The mixed culture biodegraded metal-EDTA complexes slowly; the biodegradability was in the order Fe>Cu>Co>Ni>Cd. By incorporation of inorganic phosphate into the medium as a precipitant ligand, heavy metals were removed in parallel to EDTA degradation. The mixed culture also utilized a number of possible EDTA degradation intermediates as carbon sources. PMID:9546167

  13. 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

  14. 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

  15. New optical material europium EDTA complex in polyvinyl pyrrolidone films with fluorescence enhanced by silver plasmons

    NASA Astrophysics Data System (ADS)

    Reisfeld, Renata; Saraidarov, Tsiala; Panzer, Gerard; Levchenko, Viktoria; Gaft, Michael

    2011-12-01

    In our search for efficient Luminescent Solar Concentrators (LSC) we have prepared polyvinyl pyrrolidone (PVP) films incorporated by ethylenediamine tetraacetic acid (EDTA) complex of europium and co-doped with silver nanoparticles (NPs). Steady state fluorescence was studied under weak and strong excitation. Dynamical study was performed by second harmonic of Nd laser. Under weak excitation the fluorescence of europium co-doped with silver plasmons increased by a factor of three and excited by continuous laser by a factor of 50. The lifetimes of films doped by the complex were 755 μs and co-doped with silver nanoparticles 946 μs. This is the first finding that the photon density accumulates the number of plasmons interacting with electronic states of europium increasing its transition probability resulting in the strong intensification of fluorescence. In dynamical measurements of lifetimes a single pulse does not provide enough energy to create such number of plasmons.

  16. Hepatobiliary delivery of polyaminopolycarboxylate chelates: Synthesis and characterization of a cholic acid conjugate of EDTA and biodistribution and imaging studies with its indium-111 chelate

    SciTech Connect

    Betebenner, D.A.; Carney, P.L.; Zimmer, A.M.; Kazikiewicz, J.M.; Bruecher, E.S.; Sherry, A.D.; Johnson, D.K. )

    1991-03-01

    A conjugate in which the steroid nucleus of cholic acid was linked to EDTA via an 11-atom spacer was obtained by reacting the succinimidyl ester of cholic acid with the amine formed by reaction of a benzyl isothiocyanate derivative of EDTA with N-(tert-butoxycarbonyl)ethylenediamine and subsequent deprotection. Potentiometric titration studies with model complexes showed that the EDTA moiety retained the ability to form 1:1 chelates of high thermodynamic stability, although formation constants were some 3-4 log K units lower for complexes of the conjugate than for the analogous chelates with underivatized EDTA. A complex formed between the cholic acid-EDTA conjugate and 111InIII was clearly rapidly into the liver when injected iv into mice, with subsequent excretion from the liver into the gastrointestinal tract being complete within 1 h of injection. Radioscintigraphic imaging studies conducted in a rabbit given the 111In-labeled conjugate also showed early liver uptake followed by rapid clearance from the liver into the intestine, with good visualization of the gallbladder in images obtained at 20-25 min postinjection. It is concluded that conjugation to cholic acid provides a useful means for the hepatobiliary delivery of EDTA chelates that otherwise exhibit predominantly extracellular distribution and renal clearance.

  17. Hepatobiliary delivery of polyaminopolycarboxylate chelates: synthesis and characterization of a cholic acid conjugate of EDTA and biodistribution and imaging studies with its indium-111 chelate.

    PubMed

    Betebenner, D A; Carney, P L; Zimmer, A M; Kazikiewicz, J M; Brücher, E; Sherry, A D; Johnson, D K

    1991-01-01

    A conjugate in which the steroid nucleus of cholic acid was linked to EDTA via an 11-atom spacer was obtained by reacting the succinimidyl ester of cholic acid with the amine formed by reaction of a benzyl isothiocyanate derivative of EDTA with N-(tert-butoxycarbonyl)ethylenediamine and subsequent deprotection. Potentiometric titration studies with model complexes showed that the EDTA moiety retained the ability to form 1:1 chelates of high thermodynamic stability, although formation constants were some 3-4 log K units lower for complexes of the conjugate than for the analogous chelates with underivatized EDTA. A complex formed between the cholic acid-EDTA conjugate and 111InIII was clearly rapidly into the liver when injected iv into mice, with subsequent excretion from the liver into the gastrointestinal tract being complete within 1 h of injection. Radioscintigraphic imaging studies conducted in a rabbit given the 111In-labeled conjugate also showed early liver uptake followed by rapid clearance from the liver into the intestine, with good visualization of the gallbladder in images obtained at 20-25 min postinjection. It is concluded that conjugation to cholic acid provides a useful means for the hepatobiliary delivery of EDTA chelates that otherwise exhibit predominantly extracellular distribution and renal clearance. PMID:1907855

  18. Sol-gel processing and characterization of potassium niobate nano-powders by an EDTA/citrate complexing method

    NASA Astrophysics Data System (ADS)

    Cao, Yang; Zhu, Kongjun; Qiu, Jinhao; Pang, Xuming; Ji, Hongli

    2012-05-01

    The present research describes a modified sol-gel technique used to obtain nano-crystalline potassium niobate (KNbO3) powders by using ethylene diamine tetraacetic acid (EDTA)/citrate as a complexing agent. The metal ions chemically interact with EDTA in the precursor sol. The aging treatments lead to the formation of a precursor-polymeric gel network. The effects of the amounts of citric acid and EDTA on the stability of the precursor sol are investigated. The influence of excess K on the formation of pure-phase KNbO3 powders is also studied. The obtained gels and powders are characterized by thermogravimetric-differential scanning calorimetry, X-ray diffraction, scanning electron microscopy, and transmission electron microscopy. The results indicate that a stable precursor sol is formed when n(CA):n(Mn+) = 3:1 and n(EDTA) :n(NH4OH) = 1:3.5. The xerogel is calcined at 700-850 °C to prepare the KNbO3 nano-powder. The smallest grain size of the sample obtained at 850 °C is about 60 nm when the K/Nb molar ratio equals 1.2.

  19. 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

  20. 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.

  1. 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.

  2. 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

  3. Effects of EDTA and low molecular weight organic acids on soil solution properties of a heavy metal polluted soil.

    PubMed

    Wu, L H; Luo, Y M; Christie, P; Wong, M H

    2003-02-01

    A pot experiment was conducted to study the effects of EDTA and low molecular weight organic acids (LMWOA) on the pH, total organic carbon (TOC) and heavy metals in the soil solution in the rhizosphere of Brassica juncea grown in a paddy soil contaminated with Cu, Zn, Pb and Cd. The results show that EDTA and LMWOA have no effect on the soil solution pH. EDTA addition significantly increased the TOC concentrations in the soil solution. The TOC concentrations in treatments with EDTA were significantly higher than those in treatments with LMWOA. Adding 3 mmol kg(-1) EDTA to the soil markedly increased the total concentrations of Cu, Zn, Pb and Cd in the soil solution. Compared to EDTA, LMWOA had a very small effect on the metal concentrations. Total concentrations in the soil solution followed the sequence: EDTA > citric acid (CA) approximately oxalic acid (OA) approximately malic acid (MA) for Cu and Pb; EDTA > MA > CA approximately OA for Zn; and EDTA > MA > CA > OA for Cd. The labile concentrations of Cu, Zn, Pb and Cd showed similar trends to the total concentrations. PMID:12688497

  4. 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...

  5. 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

  6. The Nuclear Quadrupole Interaction of 187W(β-)187Re in W(VI)-EDTA Complexes

    NASA Astrophysics Data System (ADS)

    Sun, Guida; Liu, Weiqiao; Butz, Tilman

    2002-07-01

    The nuclear quadrupole interaction of 187W(β-)187Re in W(VI)-EDTA complexes at room temperature was determined by time differential perturbed angular correlations (TDPAC) to be VQ = 1270(8) MHz with an asymmetry parameter η= 0.403(4). While the coordination geometry of the Mo(VI)- EDTA complex is known, there appears to be none for the W-analogue. The rather similar asymmetry parameters for the 187W(β-)187Re in W(VI)-EDTA complex and for the 99Mo(β-)99Tc in Mo(VI)- EDTA complex, determined previously, supports the idea that the coordination geometries in the Moand W-complexes are similar

  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. The sol gel synthesis of perovskites by an EDTA/citrate complexing method involves nanoscale solid state reactions

    NASA Astrophysics Data System (ADS)

    Feldhoff, A.; Arnold, M.; Martynczuk, J.; Gesing, Th. M.; Wang, H.

    2008-06-01

    Nowadays, sol-gel procedures are well established in the synthesis of complex oxides as they allow to obtain phase pure products and to control precisely their stoichiometry. This quality makes them a tool of choice for the preparation of perovskite-type oxides. To optimize the functional properties of these materials, it is essential to set accurately their possible complex stoichiometries. However, details of the formation of the perovskite crystal remain obscure. Different stages of an ethylene-diamine-tetraacetic acid (EDTA)/citrate-gel based synthesis process for mixed conducting (Ba 0.5Sr 0.5)(Fe 0.8Zn 0.2)O 3- δ of cubic perovskite structure are elucidated. The combination of analytical transmission electron microscopy with X-ray diffraction reveals that the perovskite-type oxide is formed already at moderate temperatures at around 700 °C via nanoscale solid state reactions between finely-dispersed crystalline intermediates identified as a spinel and a carbonate. The reaction scheme, however, is intricate and includes stuffed tridymite structures as transient phases. The ultrafine intermixing of extremely small reactants makes EDTA/citrate-gel based procedures superior to classical solid state routes with respect to applications that demand phase purity and stoichiometry control.

  11. 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.

  12. 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

  13. Alkaline biosolids and EDTA for phytoremediation of an acidic loamy soil spiked with cadmium.

    PubMed

    Wong, Jonathan W C; Wong, Winnie W Y; Wei, Zhenggui; Jagadeesan, Hema

    2004-05-25

    A greenhouse experiment was conducted to investigate the growth of Brassica juncea and Cd phytoextraction in a mimicked Cd contaminated acidic loamy soil amended with alkaline biosolids, prepared from sewage sludge and coal fly ash, in the presence and absence of EDTA at 2 mmol kg(-1). The acidic loamy soil was spiked with 0, 5, 20, 50 and 100 mg Cd kg(-1) in the form of CdCO(3) and then amended with 4% alkaline biosolids (w/w). Alkaline biosolids and 0.12% CaCO(3) amendments resulted in a higher biomass than unamended soil spiked with 20 mg kg(-1) Cd where plants did not survive and of the two amendments, alkaline biosolids amendment had higher plant dry weight yield and phytoextraction of Cd. Adding 2 mmol kg(-1) EDTA to alkaline biosolids amended soil significantly increased the solubility of Cd ions by 9- to 29-fold, but plant Cd accumulation decreased by a factor of 24-48%. The results indicate that alkaline biosolids amendment is an effective approach for assisting growth of B. juncea and phytoextraction of Cd from the contaminated acidic loamy soil, but further application of chelating agents did not enhance the phytoextraction efficiency of Cd. PMID:15081709

  14. Determination of NTA and EDTA and speciation of their metal complexes in aqueous solution by capillary electrophoresis

    SciTech Connect

    Owens, G.; Ferguson, V.K.; McLaughlin, M.J.; Singleton, I.; Reid, R.J.; Smith, F.A.

    2000-03-01

    The interest in the use of chelates for enhancing metal uptake by plants during phytoremediation and their widespread use in plant nutrient research requires that an easy, reproducible method be developed for chelate detection in a variety of systems. This work examined the use of capillary electrophoresis for chelate analysis. Electropherograms for nitrilotriacetic acid (NTA) and ethylenediaminetetraacetic acid (EDTA) and their metal complexes were obtained by capillary electrophoresis in a phosphate buffer by direct UV detection at 185 nm. The metals used were Va(II), Co(II), Ni(II), Cu(II), Zn(II), Cd(II), Pb(II), and Fe(III). For the majority of metals studied, linear calibration curves were obtained in the concentration range of 10--1,000 {micro}M. The direct method of determination at 185 nm was found to give a higher detection sensitivity than direct detection at 254 nm. Limits of detection for the metal chelate complexes were in the range of 2--50 {micro}m. The analysis was fast (<6 min), exhibited low relative standard deviations for retention time (<1%) and peak corrected area (<5%), and required no complex sample pretreatment. The method was used to demonstrate speciation in complex nutrient media.

  15. 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.

  16. 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. PMID:23306229

  17. 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. PMID:24873699

  18. 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

  19. 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

  20. A comparative evaluation of smear layer removal by using edta, etidronic acid, and maleic acid as root canal irrigants: An in vitro scanning electron microscopic study

    PubMed Central

    Kuruvilla, Aby; Jaganath, Bharath Makonahalli; Krishnegowda, Sahadev Chickmagaravalli; Ramachandra, Praveen Kumar Makonahalli; Johns, Dexton Antony; Abraham, Aby

    2015-01-01

    Aim: The purpose of this study is to evaluate and compare the efficacy of 17% EDTA, 18% etidronic acid, and 7% maleic acid in smear layer removal using scanning electron microscopic image analysis. Materials and Methods: Thirty, freshly extracted mandibular premolars were used. The teeth were decoronated to obtain working length of 17mm and instrumentation up to 40 size (K file) with 2.5% NaOCl irrigation between each file. The samples were divided into Groups I (17% ethylenediaminetetraacetic acid (EDTA)), II (18% etidronic acid), and III (7% maleic acid) containing 10 samples each. Longitudinal sectioning of the samples was done. Then the samples were observed under scanning electron microscope (SEM) at apical, middle, and coronal levels. The images were scored according to the criteria: 1. No smear layer, 2. moderate smear layer, and 3 heavy smear layer. Statistical Analysis: Data was analyzed statistically using Kruskal–Wallis analysis of variance (ANOVA) followed by Mann-Whitney U test for individual comparisons. The level for significance was set at 0.05. Results: The present study showed that all the three experimental irrigants removed the smear layer from different tooth levels (coronal, middle, and apical). Final irrigation with 7% maleic acid is more efficient than 17% EDTA and 18% etidronic acid in the removal of smear layer from the apical third of root canal. PMID:26069414

  1. Cytotoxic and genotoxic potential of Cr(VI), Cr(III)-nitrate and Cr(III)-EDTA complex in human hepatoma (HepG2) cells.

    PubMed

    Novotnik, Breda; Ščančar, Janez; Milačič, Radmila; Filipič, Metka; Žegura, Bojana

    2016-07-01

    Chromium (Cr) and ethylenediaminetetraacetate (EDTA) are common environmental pollutants and can be present in high concentrations in surface waters at the same time. Therefore, chelation of Cr with EDTA can occur and thereby stable Cr(III)-EDTA complex is formed. Since there are no literature data on Cr(III)-EDTA toxicity, the aim of our work was to evaluate and compare Cr(III)-EDTA cytotoxic and genotoxic activity with those of Cr(VI) and Cr(III)-nitrate in human hepatoma (HepG2) cell line. First the effect of Cr(VI), Cr(III)-nitrate and Cr(III)-EDTA on cell viability was studied in the concentration range from 0.04 μg mL(-1) to 25 μg mL(-1) after 24 h exposure. Further the influence of non-cytotoxic concentrations of Cr(VI), Cr(III)-nitrate and Cr(III)-EDTA on DNA damage and genomic stability was determined with the comet assay and cytokinesis block micronucleus cytome assay, respectively. Cell viability was decreased only by Cr(VI) at concentrations above 1.0 μg mL(-1). Cr(VI) at ≥0.2 μg mL(-1) and Cr(III) at ≥1.0 μg mL(-1) induced DNA damage, while after Cr(III)-EDTA exposure no formation DNA strand breaks was determined. Statistically significant formation of micronuclei was induced only by Cr(VI) at ≥0.2 μg mL(-1), while no influence on the frequency of nuclear buds nor nucleoplasmic bridges was observed at any exposure. This study provides the first evidence that Cr(III)-EDTA did not induce DNA damage and had no influence on the genomic stability of HepG2 cells. PMID:27043378

  2. 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). PMID:12206435

  3. 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. PMID:22555067

  4. Synthesis and properties of samaria-doped ceria electrolyte for IT-SOFCs by EDTA-citrate complexing method

    NASA Astrophysics Data System (ADS)

    Wu, Wen-Chang; Huang, Jui-Ting; Chiba, Atsushi

    An ultra-fine samaria-doped ceria (Ce 0.8Sm 0.2O 1.9, SDC) electrolyte prepared by a non-ion selective EDTA-citric complexing method is developed herein for intermediate-temperature solid oxide fuel cells (IT-SOFCs). The rigid agglomerates due to organic compounds that exist in the SDC precursors during the EDTA-citrate complexing synthesis process inhibit crystalline growth and grain growth, leading to the generation of ultra-fine grain following the sintering procedure. Calcination is necessary above 500 °C for all precursors. The average grain size of the pellets after sintering at 1400 °C for 2 h is submicron in scale (from 200 nm to 600 nm) with various pH values, and the pellets are smaller than those obtained from other synthesis processes. Dense pellets with pH values of 10 (relative density of 99%) are obtained with precursor powder calcination at 900 °C for 3 h. Electrical conductivity is dependent on the calcination temperature and pH value of the solution, and the maximum electrical conductivity is 0.01 S cm -1 at 700 °C with a pH value of 10.

  5. 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

  6. Investigations on the conditional kinetic and thermodynamic stability of aquatic humic substance-metal complexes by means of EDTA exchange, ultrafiltration and atomic spectrometry.

    PubMed

    Van den Bergh, J; Jakubowski, B; Burba, P

    2001-09-13

    The conditional metal availability and the kinetic stability of humic substance-metal species in humic-rich waters (e.g. bog water) was characterized by means of EDTA exchange. For this purpose a combined procedure consisting of time-controlled ligand exchange by EDTA, species differentiation by a fast single-stage tangential-flow ultrafiltration (TF-UF) technique (cut-off 1 kDa) and sensitive atomic spectrometry methods (e.g. AAS, ICP-OES, TXRF) was developed. The kinetics and the yield of the EDTA exchange served as operational parameters for assessing the kinetic stability and EDTA availability of HS-metal species, respectively. Considerable fractions of natural HS-metal species studied were shown to be EDTA-inert (e.g. 31% of the total Fe, 44% of the total Al) even after long reaction times (48 h), in contrast to artificial ones formed in solutions of isolated HS. Moreover, the conditional thermodynamic stability of HS-metal complexes formed by successive loading of an aquatic reference HS (HO14) with a number of heavy metal ions (e.g. Cr(III), Cu(II), Fe(III), Mn(II), Zn(II)) was also evaluated discriminating the free metal concentrations by means of TF-UF. In addition, from the loading isotherms obtained conditional complexation capacities could be derived for the studied HS exhibiting the order Fe(III)>Cu(II)>Cr(III)>Co(II)>Mn(II). PMID:18968404

  7. Kinetics and mechanism of the reaction of [RuIII(edta)(H2O)]- with HOBr to form an intermediate RuV=O complex in aqueous solution.

    PubMed

    Chatterjee, Debabrata; Mitra, Anannya; van Eldik, Rudi

    2006-10-21

    The interaction of [Ru(III)(edta)(H(2)O)](-) (1) (edta = ethylenediaminetetraacetate) with the oxygen transfer agent HOBr, was studied kinetically as a function of [HOBr] and temperature (5-35 degrees C) at a fixed pH of 6.2. Spectroscopic evidence is reported for the formation of a high valent intermediate (edta)Ru(V)=O complex. Water soluble 2,2'-azobis(3-ethylbenzithiazoline-6-sulfonate) (ABTS) was employed as a trap for this intermediate in order to gain further mechanistic information. Reactions were carried out under pseudo-first conditions for [ABTS] > [HOBr] > [1], and were monitored as a function of time for the formation of the one-electron oxidation product ABTS(*+). The reported kinetic data are interpreted in terms of a suggested reaction mechanism and discussed in reference to data reported before. PMID:17028677

  8. Stability constants of the ternary complexes of CuDTPA, NiDCTA, CrEDTA, CoHEEDTA, NiHEEDTA and CuHEEEDT Aheedta with OH-.

    PubMed

    Korsse, J; Leurs, G A; Louwrier, P W

    1985-06-01

    The acid dissociation constants of the metal chelates H(3)CuDTPA, H(2) NiDCTA, HCrEDTA, HCoHEEDTA, HNiHEEDTA and HCuHEEDTA were determined by potentiometric titration. The constants determined at an ionic strength of 0.1 were pK(a,1) = 2.1; pK(a,2) = 2.8 and pK(a,3) = 4.75 for H(3) CuDTPA (296 K), pK(a,1) = 2.16 for HCrEDTA (298 K); pK(a,1) = 1.6 and pK(a,2) = 2.0 for H(2) NiDCTA (298 K); pK(a,1) = 2.24 for HCoHEEDTA, pK(a,1) = 2.47 for HCuHEEDTA and pK(a,1) = 1.73 for HNi-HEEDTA. At high pH the formation of ternary hydroxo-complexes was observed for the chelates CrEDTA(-) (pK(a,1) = 7.35; pK(a,1) = 12.35), CoHEEDTA(-) (pK(a,1) = 11.74), NiHEEDTA(-) (pK(a,2) = 12,44) and CuHEEDTA(-) (pK(a,2) = 10.45). PMID:18963877

  9. 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

  10. Extraction of nickel from spent catalyst using fresh and recovered EDTA.

    PubMed

    Goel, Shina; Pant, K K; Nigam, K D P

    2009-11-15

    This study investigates the possibility of recovering nickel from spent catalyst (NiO/Al(2)O(3)) used in the fertilizer industry. EDTA (ethylenediaminetetraaceticacid) di sodium salt was used as a chelating to extract the Ni after which sulfuric acid was added to obtain NiSO(4). The dechelation process takes 5-6h to break the complex and EDTA which was recovered as H(4)EDTA acid in the solid form and solution contains NiSO(4). The objective was to evaluate the nickel removal efficiency of EDTA and reusability of recovered EDTA. The parameters affecting nickel recovery were EDTA concentration, time of chelation, catalyst to liquid ratio (s:l), mixing speed, pH and catalyst particle size. The extraction was up to 95% under the following conditions: 0.8M concentration of EDTA, solid to liquid ratio 1:50 (g/ml), particle size 100 microm, pH 10, 10h of chelation time, 700 rpm and 100 degrees C. Up to 95% of the EDTA could be recovered without losing significant activity. PMID:19553011

  11. IN VITRO INHIBITORY AND FUNGICIDAL PROPERTIES OF EDTA FOR ASPERGILLUS AND FUSARIUM

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Background: Ethylenediaminetetra-acetic acid (EDTA) is approved for food preservation, treatment for hypercalcemia and heavy metal poisoning and as a blood count tube anticoagulant. Reports indicate EDTA also inhibits microbial growth. This study investigated EDTA lethality and inhibitory propert...

  12. Mechanism of permeability-enhancing effect of EDTA and boric acid on the corneal penetration of 4-[1-hydroxy-1-methylethyl]-2-propyl-1-[4-[2-[tetrazole-5-yl]phenyl]phenyl] methylimidazole-5-carboxylic acid monohydrate (CS-088).

    PubMed

    Kikuchi, Takayuki; Suzuki, Masahiko; Kusai, Akira; Iseki, Ken; Sasaki, Hitoshi; Nakashima, Kenichiro

    2005-08-11

    This study was conducted to clarify the penetration properties of 4-[1-hydroxy-1-methylethyl]-2-propyl-1-[4-[2-[tetrazole-5-yl]phenyl]phenyl]methylimidazole-5-carboxylic acid monohydrate (CS-088), an ophthalmic agent, and the mechanism of the permeability-enhancing effect of EDTA and boric acid (EDTA/boric acid) on the corneal penetration of CS-088. In the absence of additives, corneal permeability decreased with increasing concentration of CS-088 as CS-088 monomers self-associate to form dimers. Presence of EDTA/boric acid caused no significant changes in the physicochemical properties of CS-088, the apparent partition coefficient or the mean particle size of CS-088. EDTA/boric acid induced only a slight change in the zeta potential of liposomes used as a model of the biological membrane. On the other hand, EDTA/boric acid significantly increased membrane fluidity of liposomes, whereas other buffering agents tested did not. This effect was synergistic and concentration-dependent for both EDTA and boric acid as was observed in in vitro corneal penetration of CS-088. In accordance with the result, the rate of CS-088 permeation into the liposomes significantly increased by the addition of EDTA/boric acid. Therefore, it was demonstrated that EDTA/boric acid promotes corneal penetration of CS-088 through the transcellular pathway by increasing membrane fluidity. Conversely, other buffering agents decreased corneal permeability of CS-088 by inducing further self-association of CS-088 aggregates. PMID:15979832

  13. 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

  14. 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

  15. 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.

  16. 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

  17. EDTA-assisted Pb phytoextraction.

    PubMed

    Saifullah; Meers, E; Qadir, M; de Caritat, P; Tack, F M G; Du Laing, G; Zia, M H

    2009-03-01

    Pb is one of the most widespread and metal pollutants in soil. It is generally concentrated in surface layers with only a minor portion of the total metal found in soil solution. Phytoextraction has been proposed as an inexpensive, sustainable, in situ plant-based technology that makes use of natural hyperaccumulators as well as high biomass producing crops to help rehabilitate soils contaminated with heavy metals without destructive effects on soil properties. The success of phytoextraction is determined by the amount of biomass, concentration of heavy metals in plant, and bioavailable fraction of heavy metals in the rooting medium. In general, metal hyperaccumulators are low biomass, slow growing plant species that are highly metal specific. For some metals such as Pb, there are no hyperaccumulator plant species known to date. Although high biomass-yielding non-hyperaccumulator plants lack an inherent ability to accumulate unusual concentrations of Pb, soil application of chelating agents such as EDTA has been proposed to enhance the metal concentration in above-ground harvestable plant parts through enhancing the metal solubility and translocation from roots to shoots. Leaching of metals due to enhanced mobility during EDTA-assisted phytoextraction has been demonstrated as one of the potential hazards associated with this technology. Due to environmental persistence of EDTA in combination with its strong chelating abilities, the scientific community is moving away from the use of EDTA in phytoextraction and is turning to less aggressive alternative strategies such as the use of organic acids or more degradable APCAs (aminopolycarboxylic acids). We have therefore arrived at a point in phytoremediation research history in which we need to distance ourselves from EDTA as a proposed soil amendment within the context of phytoextraction. However, valuable lessons are to be learned from over a decade of EDTA-assisted phytoremediation research when considering the

  18. Identification and characterization of the two-enzyme system catalyzing oxidation of EDTA in the EDTA-degrading bacterial strain DSM 9103.

    PubMed Central

    Witschel, M; Nagel, S; Egli, T

    1997-01-01

    In a gram-negative isolate (DSM 9103) able to grow with EDTA as the sole source of carbon, nitrogen, and energy, the first two steps of the catabolic pathway for EDTA were elucidated. They consisted of the sequential oxidative removal of two acetyl groups, resulting in the formation of glyoxylate. An enzyme complex that catalyzes the removal of two acetyl groups was purified and characterized. In the reaction, ethylenediaminetriacetate (ED3A) was formed as an intermediate and N,N'-ethylenediaminediacetate was the end product. The enzyme complex consisted of two components: component A' (cA'), most likely a monooxygenase, which catalyzes the cleavage of EDTA and ED3A while consuming oxygen and reduced flavin mononucleotide (FMN)-H2, and component B' (cB'), an NADH2:FMN oxidoreductase that provides FMNH2 for cA'. cB' could be replaced by other NADH2:FMN oxidoreductases such as component B of the nitrilotriacetate monooxygenase or the NADH2:FMN oxidoreductase from Photobacterium fischeri. The EDTA-oxidizing enzyme complex accepted EDTA as a substrate only when it was complexed with Mg2+, Zn2+, Mn2+, Co2+, or Cu2+. Moreover, the enzyme complex catalyzed the removal of acetyl groups from several other aminopolycarboxylic acids that possess three or more acetyl groups. PMID:9371437

  19. Ligand design for enhanced stereoselectivity in the electron-transfer reactions between nickel(IV) bis(oxime-imine) complexes and (Co(edta))/sup 2 -/

    SciTech Connect

    Martone, D.P.; Osvath, P.; Lappin, A.G.

    1987-09-23

    A number of derivatives of the sexidentate bis(oxime-imine) ligand 3,14-dimethyl-4,7,10,13-tetraazahexadeca-3,13-diene-2,15-dione dioxime, Me/sub 2/L(1)H/sub 2/, have been prepared in which the methyl groups on the oxime-imine chromophores are replaced by more bulky phenyl groups, MePhL(1)H/sub 2/ and PhMeL(1)H/sub 2/, or chiral (S) methyl (L(2)) and benzyl (L(3)) groups are attached on the amine backbone at the 5- and 12-positions. Nickel(II) complexes of the ligands can be oxidized to the corresponding nickel(III) and nickel(IV) derivatives, and the effect of changing ligand structure on the reduction potentials of the complexes is small. Self-exchange rate constants for the nickel(IV)/nickel(III) change have been estimated from the rates of the cross-reactions between (Ni/sup III/MePhL(1))/sup +/ and (Ni/sup III/PhMeL(1))/sup +/ and their chiral (5S, 12S)-dimethyl nickel(IV) derivatives to be 8 x 10/sup 5/ and 4 x 10/sup 6/ M/sup -1/ s/sup -1/, respectively, at 25/sup 0/C and 0.1 M ionic strength. The kinetics and mechanisms of reduction of (Ni/sup IV/MePhL(1))/sup 2 +/ and (Ni/sup IV/PhMeL(1))/sup 2 +/ and (Co(edta))/sup 2 -/ have also been investigated. Stereoselectivity in the oxidation of (Co(edta))/sup 2 -/ by nickel(IV) has been investigated by using these chiral complexes, and in all cases the preferred isomer of the product (Co(edta))/sup -/ is ..delta.. with enantiomeric excesses of 7%, 21%, 22%, and 46% for the complexes (Ni/sup IV/PhMeL(2))/sup 2 +/, (Nk/sup IV/MePhL(2))/sup 2 +/, (Ni/sup IV/Me/sub 2/L(3))/sup 2 +/, and (Ni/sup IV/MePhL(3))/sup 2 +/, respectively. 32 references, 5 figures, 4 tables.

  20. Effect Of EDTA On Luminescence Property Of Eu+3 Doped YPO4 Nanoparticles

    NASA Astrophysics Data System (ADS)

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

    2010-12-01

    Nanoparticles of Eu3+ doped YPO4 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 Eu3+ activators per unit volume. These materials are dispersible in water, which may have potential biological applications.

  1. 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

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

    PubMed Central

    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. PMID:25120359

  3. On hafnium chelation by EDTA and DTPA for TDPAC experiments

    NASA Astrophysics Data System (ADS)

    Chain, Cecilia Y.; Pasquevich, A. F.

    2010-04-01

    Polyaminocarboxilate chelating agents, like ethylenediaminetetraacetic acid (EDTA) and diethylenetriaminepentaacetic acid (DTPA), form stable complexes with many heavy metals ions and are of spread use in the industrial and biomedical field. In this paper, Time Differential Perturbed Angular Correlations (TDPAC) spectroscopy has been used to investigate the formation of Hf-complexes prepared from 181Hf-HfF4 and polyaminocarboxylic acids, by taking into account the possible formation of inorganic compounds. The obtained wet precipitates were measured at room temperature. Different behaviors were observed depending on the ratio fluorine/sodium atoms present in the sample. The obtaining of sodium heptafluorohafnate Na3HfF7 was verified when the ratio F/Na was approximately 1.5 and tridecafluorodihafnate Na5Hf2F13 appeared for relations between 3 and 4. No evidence of hafnium complexation by the polyaminocarboxilic acids was observed.

  4. 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

  5. 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.

  6. 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

  7. 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

  8. 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

  9. 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

  10. 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.

  11. 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

  12. 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.

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

    DOE PAGESBeta

    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

  14. 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

  15. 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

  16. 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

  17. Transient EDTA-dependent pseudothrombocytopenia in a patient with sepsis.

    PubMed

    Mori, M; Kudo, H; Yoshitake, S; Ito, K; Shinguu, C; Noguchi, T

    2000-02-01

    Ethylenediaminetetraacetic acid-dependent pseudothrombocytopenia (EDTA-PTCP) is the phenomenon of a spurious low platelet count due to antiplatelet antibodies that cause platelet clumping in blood anticoagulated with EDTA. We describe a case of EDTA-PTCP that appeared transiently with the development of sepsis. A 50-year-old man underwent Bentall's aortic root replacement for acute aortic dissection with aortic insufficiency. Postoperatively the patient suffered paralytic ileus followed by methicillin-resistant Staphylococcus aureus enteritis and septicemia with endotoxemia. EDTA-PTCP appeared with the development of sepsis, and disappeared with its resolution. To avoid incorrect diagnoses and inappropriate treatment, EDTA-PTCP should always be considered as a possible cause of reported low platelet counts, even in patients with sepsis. PMID:10784313

  18. Novel polycarboxylated EDTA-type cyclodextrins as ligands for lanthanide binding: study of their luminescence, relaxivity properties of Gd(iii) complexes, and PM3 theoretical calculations.

    PubMed

    Maffeo, Davide; Lampropoulou, Maria; Fardis, Michael; Lazarou, Yannis G; Mavridis, Irene M; Mavridou, Despoina A I; Urso, Elena; Pratsinis, Harris; Kletsas, Dimitris; Yannakopoulou, Konstantina

    2010-04-21

    Novel -type cyclodextrin (CD) derivatives, , and , bearing 6, 7 and 8 bis(carboxymethyl)amino (iminodiacetic acid) groups, respectively, were prepared, and their complexation with Eu(iii), Tb(iii) and Gd(iii) ions was studied. Luminescence titrations and mass spectrometry showed formation of multimetal complexes ( 2 to 3, mainly 3 and exactly 4 metal ions), whereas luminescence lifetime measurements revealed the presence of exchangeable water molecules. Semiempirical quantum mechanical calculations, performed by the PM3 method and assessed by DFT calculations on model ligands, indicated efficient multi-metal complexation, in agreement with the experiment. The structures showed coordination of the metal ions in the outer primary side of the CDs via 4 carboxylate O atoms, 2 N atoms and a glucopyranose O atom per metal ion. Coordination of water molecules was also predicted, in accordance with experimental results. Calculated bond lengths and angles were in agreement with literature experimental values of lanthanide complexes. Calculated energies showed that complex stability decreases in the order > > . (1)H NMR molecular relaxivity measurements for the Gd(iii) complexes of , or in water afforded values 4 to 10 times higher than the relaxivity of a commercial contrast agent at 12 MHz, and 6 to 20 times higher at 100 MHz. Solutions of and Gd(iii) complexes in human blood plasma displayed relaxivity values at 100 MHz 7 and 12 times, respectively, higher than the commercial agent. MTT tests of the Gd(iii) complexes using human skin fibroblasts did not show toxicity. Attempts to supramolecularly sensitize the luminescence of the lanthanide complexes using various aromatic CD guests were ineffective, evidently due to large guest-metal distances and inefficient inclusion. The described lanthanide complexes, could be useful as contrast agents in MRI. PMID:20449498

  19. 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

  20. 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

  1. Transport of Sr 2+ and SrEDTA 2- in partially-saturated and heterogeneous sediments

    NASA Astrophysics Data System (ADS)

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

    2007-05-01

    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 that

  2. 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. PMID:26827296

  3. Controlled hydrothermal growth of ZnO nanostructures by sequestering the Zn metal ions with the chelating agent EDTA

    NASA Astrophysics Data System (ADS)

    Ram, S. D. Gopal; Ravi, G.; Manikandan, MR.; Mahalingam, T.; Anbu Kulandainathan, M.

    2011-10-01

    In the present work, a controlled growth of ZnO nanostructures by manipulating Zn metal ion concentration by the chelating action of ethylene diaminetetra acetic acid in hydrothermal method is studied. EDTA produces metal-chelate complex by the formation of bidentate ligand with Zn 2+ in the solution and diminishes the reactivity of Zn metal cations. Concentration of EDTA in the mother solution was varied in different ranges like 3, 5 and 10 mM while retaining the zinc metal salt and the NaOH concentration the same. Three different morphologies of wurtzite structured ZnO nanostructures such as nanorods-bunch, separate/discrete uniformly sized hexagonal nanorods and tapered flower petals like shapes are achieved by 3, 5 and 10 mM strengths of EDTA, respectively. The medium concentration 5 mM of EDTA is found to have moderate control over producing ZnO nanostructures of uniform diameter and a high aspect (length to diameter) ratio. An array of vertically aligned free standing ZnO nanorods with uniform spacing is successfully achieved by the addition of 5 mM of EDTA in the mother solution and the same is studied for its fluorescence property at an excitation of 325 nm and it has exhibited a characteristic UV emission of ZnO around 383 nm.

  4. The role of EDTA in lead transport and accumulation by indian mustard

    PubMed

    Vassil; Kapulnik; Raskin; Salt

    1998-06-01

    Indian mustard (Brassica juncea) plants exposed to Pb and EDTA in hydroponic solution were able to accumulate up to 55 mmol kg-1 Pb in dry shoot tissue (1.1% [w/w]). This represents a 75-fold concentration of Pb in shoot tissue over that in solution. A threshold concentration of EDTA (0.25 mm) was found to be required to stimulate this dramatic accumulation of both Pb and EDTA in shoots. Below this threshold concentration, EDTA also accumulated in shoots but at a reduced rate. Direct measurement of a complex of Pb and EDTA (Pb-EDTA) in xylem exudate of Indian mustard confirmed that the majority of Pb in these plants is transported in coordination with EDTA. The accumulation of EDTA in shoot tissue was also observed to be directly correlated with the accumulation of Pb. Exposure of Indian mustard to high concentrations of Pb and EDTA caused reductions in both the transpiration rate and the shoot water content. The onset of these symptoms was correlated with the presence of free protonated EDTA (H-EDTA) in the hydroponic solution, suggesting that free H-EDTA is more phytotoxic than Pb-EDTA. These studies clearly demonstrate that coordination of Pb transport by EDTA enhances the mobility within the plants of this otherwise insoluble metal ion, allowing plants to accumulate high concentrations of Pb in shoots. The finding that both H-EDTA and Pb-EDTA are mobile within plants also has important implications for the use of metal chelates in plant nutritional research. PMID:9625697

  5. 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.

  6. 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

  7. Coordination studies of Al-EDTA in aqueous solution.

    PubMed

    Coskuner, Orkid; Jarvis, Emily A A

    2008-03-27

    The degree of aluminum toxicity is based on its complexation with organic ligands. One of these complexes is AlEDTA- (Al = aluminum, EDTA = ethylenediaminetetraacetate), the structure of which in aqueous solution has been debated on the basis of X-ray absorption and NMR measurements with different interpretations proposing different coordination. In addition, there is a lack of consensus regarding the relationship of crystalline AlEDTA- and its geometry in solution. This debate must be resolved, not merely for scientific interest, but because the use of an incorrect coordination might lead to the wrong interpretation of bioactivity and kinetics data. In this work, we predict the coordination of Al in aqueous AlEDTA- by employing ab initio calculations and Car-Parrinello molecular dynamics simulations. Our results indicate that AlEDTA- favors Al in octahedral coordination in aqueous solution. Furthermore, the predicted crystalline and solution-phase structures of AlEDTA- are similar and agree well with recent X-ray measurements, supporting the strong chelating nature of this metal-organic complex in aqueous solution. PMID:18293948

  8. Reduction of Fe(II)EDTA-NO by a newly isolated Pseudomonas sp. strain DN-2 in NOx scrubber solution.

    PubMed

    Zhang, Shi-Han; Li, Wei; Wu, Cheng-Zhi; Chen, Han; Shi, Yao

    2007-10-01

    Biological reduction of nitric oxide (NO) chelated by ferrous ethylenediaminetetraacetate (Fe(II)EDTA) to N2 is one of the core processes in a chemical absorption-biological reduction integrated technique for nitrogen oxide (NOx) removal from flue gases. A new isolate, identified as Pseudomonas sp. DN-2 by 16S rRNA sequence analysis, was able to reduce Fe(II)EDTA-NO. The specific reduction capacity as measured by NO was up to 4.17 mmol g DCW(-1) h(-1). Strain DN-2 can simultaneously use glucose and Fe(II)EDTA as electron donors for Fe(II)EDTA-NO reduction. Fe(III)EDTA, the oxidation of Fe(II)EDTA by oxygen, can also serve as electron acceptor by strain DN-2. The interdependency between various chemical species, e.g., Fe(II)EDTA-NO, Fe(II)EDTA, or Fe (III)EDTA, was investigated. Though each complex, e.g., Fe(II)EDTA-NO or Fe(III)EDTA, can be reduced by its own dedicated bacterial strain, strain DN-2 capable of reducing Fe(III)EDTA can enhance the regeneration of Fe(II)EDTA, hence can enlarge NO elimination capacity. Additionally, the inhibition of Fe(II)EDTA-NO on the Fe(III)EDTA reduction has been explored previously. Strain DN-2 is probably one of the major contributors for the continual removal of NOx due to the high Fe(II)EDTA-NO reduction rate and the ability of Fe(III)EDTA reduction. PMID:17598105

  9. 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.

  10. Effect of EDTA on the bioavailability to rats of fortification iron used in Egyptian balady bread.

    PubMed

    Whittaker, P; Vanderveen, J E

    1990-05-01

    The effectiveness of EDTA compounds on iron fortificants for potential use in Egyptian balady bread was tested in sixty Sprague-Dawley weanling male rats by the haemoglobin regeneration efficiency (HRE) method. To confirm HRE-derived findings, eight groups of ten animals were repleted with a modified American Institute of Nutrition (1977; AIN) 76A diet, fortified with ferric phosphate, electrolytic Fe, carbonyl Fe or ferrous sulphate, with and without ascorbic acid. Results without ascorbic acid were comparable to findings of a human study by Forbes et al. (1989). Bioavailability of EDTA-enhanced fortificants, FeSO4 + Na2EDTA and NaFe(III)EDTA, was compared with that of FeSO4 in six groups of ten animals repleted with a ground Egyptian bread meal or a casein-based AIN diet fortified with one of the three compounds. Addition of either EDTA compound significantly increased bioavailability of Fe in Egyptian balady bread. When present in the less inhibitory casein meal, however, FeSO4 + Na2EDTA fortification was significantly less effective than NaFe(III)EDTA or the reference FeSO4. Results indicate that NaFe(III)EDTA may be the fortificant of choice in a mixed diet. Further study of EDTA-enhanced Fe fortificants is needed. PMID:2116895

  11. 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,…

  12. Effect of EDTA on the metastable zone width of ADP

    NASA Astrophysics Data System (ADS)

    Rajesh, N. P.; Meera, K.; Srinivasan, K.; Santhana Raghavan, P.; Ramasamy, P.

    2000-06-01

    Enhancement of the metastable zone width in ammonium dihydrogen ortho phosphate (ADP) was achieved by the addition of 1 mol% of the chelating agent ethylenediaminetetra acetic acid (EDTA) to ADP solution. The metastable zone width studies were conducted and the nucleation parameters were calculated from the measurements of the dependence of the metastable zone width on the cooling rate.

  13. Investigation of mechanisms of oxidation of EDTA and NTA by permanganate at high pH.

    PubMed

    Chang, Hyun-Shik; Korshin, Gregory V; Ferguson, John F

    2006-08-15

    Permanganate has been used for oxidation of nuclear wastes containing chelating agents such as ethylenediaminetetraacetic and nitrilotriacetic acids (EDTA and NTA) to improve separation of radionuclides and heavy metals from the wastes, butthe mechanisms of degradation of these and related organic ligands at high pHs have not been studied. EDTA, NTA, and the model compound ethylenediamine (EN) were found to be readily oxidized by permanganate at pH 12-14. The reduction of permangante was accompanied by formation of unstable manganate and dispersed MnO2 particles, which constituted the final product of permanganate reduction. The yields and speciation of EDTA, NTA, and EN breakdown products were affected by the pH and permanganate dose. Iminodiacetic acid (IDA), oxalate, formate, and ammonia were the predominant EDTA and NTA oxidation products. Mineralization of EDTA, NTA, and EN to CO2 was more significant at pH 12. At pH 14 formation of oxalate and deamination to NH3 were the most important reactions. IDA was released upon the oxidation of both EDTA and NTA, but EDTA oxidation yielded no ethylenediaminediacetic acid (EDDA). The speciation of the reaction products indicated that the ethylene group in EDTA was the preferred attack site in oxidations by alkaline permanganate. PMID:16955912

  14. 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 Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) FOOD ADDITIVES PERMITTED FOR DIRECT ADDITION TO FOOD FOR HUMAN CONSUMPTION Food Preservatives § 172.135 Disodium EDTA. The food additive disodium EDTA...

  15. Synthesis and characterization of TEP-EDTA-regulated bioactive hydroxyapatite

    NASA Astrophysics Data System (ADS)

    Haders, Daniel Joseph, II

    Hydroxyapatite (HA), Ca10(PO4)6(OH) 2, the stoichiometric equivalent of the ceramic phase of bone, is the preferred material for hard tissue replacement due to its bioactivity. However, bioinert metals are utilized in load-bearing orthopedic applications due to the poor mechanical properties of HA. Consequently, attention has been given to HA coatings for metallic orthopedic implants to take advantage of the bioactivity of HA and the mechanical properties of metals. Commercially, the plasma spray process (PS-HA) is the method most often used to deposit HA films on metallic implants. Since its introduction in the 1980's, however, concerns have been raised about the consequences of PS-HA's low crystallinity, lack of phase purity, lack of film-substrate chemical adhesion, passivation properties, and difficulty in coating complex geometries. Thus, there is a need to develop inexpensive reproducible next-generation HA film deposition techniques, which deposit high crystallinity, phase pure, adhesive, passivating, conformal HA films on clinical metallic substrates. The aim of this dissertation was to intelligently synthesize and characterize the material and biological properties of HA films on metallic substrates synthesized by hydrothermal crystallization, using thermodynamic phase diagrams as the starting point. In three overlapping interdisciplinary studies the potential of using ethylenediamine-tetraacetic acid/triethyl phosphate (EDTA/TEP) doubly regulated hydrothermal crystallization to deposit HA films, the TEP-regulated, time-and-temperature-dependent process by which films were deposited, and the bioactivity of crystallographically engineered films were investigated. Films were crystallized in a 0.232 molal Ca(NO3)2-0.232 molal EDTA-0.187 molal TEP-1.852 molal KOH-H2O chemical system at 200°C. Thermodynamic phase diagrams demonstrated that the chosen conditions were expected to produce Ca-P phase pure HA, which was experimentally confirmed. EDTA regulation of

  16. 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

  17. Phase Behavior of Complex Superprotonic Solid Acids

    NASA Astrophysics Data System (ADS)

    Panithipongwut, Chatr

    Superprotonic phase transitions and thermal behaviors of three complex solid acid systems are presented, namely Rb3H(SO4) 2-RbHSO4 system, Rb3H(SeO4)2-Cs 3H(SeO4)2 solid solution system, and Cs6 (H2SO4)3(H1.5PO4) 4. These material systems present a rich set of phase transition characteristics that set them apart from other, simpler solid acids. A.C. impedance spectroscopy, high-temperature X-ray powder diffraction, and thermal analysis, as well as other characterization techniques, were employed to investigate the phase behavior of these systems. Rb3H(SO4)2 is an atypical member of the M3H(XO4)2 class of compounds (M = alkali metal or NH4+ and X = S or Se) in that a transition to a high-conductivity state involves disproportionation into two phases rather than a simple polymorphic transition [1]. In the present work, investigations of the Rb3H(SO4)2-RbHSO4 system have revealed the disproportionation products to be Rb2SO 4 and the previously unknown compound Rb5H3(SO 4)4. The new compound becomes stable at a temperature between 25 and 140 °C and is isostructural to a recently reported trigonal phase with space group P3m of Cs5H 3(SO4)4 [2]. At 185 °C the compound undergoes an apparently polymorphic transformation with a heat of transition of 23.8 kJ/mol and a slight additional increase in conductivity. The compounds Rb3H(SeO4)2 and Cs 3H(SeO4)2, though not isomorphous at ambient temperatures, are quintessential examples of superprotonic materials. Both adopt monoclinic structures at ambient temperatures and ultimately transform to a trigonal (R3m) superprotonic structure at slightly elevated temperatures, 178 and 183 °C, respectively. The compounds are completely miscible above the superprotonic transition and show extensive solubility below it. Beyond a careful determination of the phase boundaries, we find a remarkable 40-fold increase in the superprotonic conductivity in intermediate compositions rich in Rb as compared to either end-member. The compound Cs6(H2

  18. Sonochemical destruction of free and metal-binding ethylenediaminetetraacetic acid.

    PubMed

    Frim, J Aaron; Rathman, James F; Weavers, Linda K

    2003-07-01

    This study focused on the sonochemical degradation of ethylenediaminetetraacetic acid (EDTA) and chromium-EDTA complexes. Degradation of the copper(II)-EDTA complex was also investigated as a comparison metal complex. A 90% degradation of a 150-microM EDTA solution with continuous O2-bubbling was shown for the 20-kHz system in approximately 3 h (kpseudo-first order = 1.22 x 10(-2) min-1) and less than 1 h for the 354-kHz system (kpseudo-first order = 5.42 x 10(-2) min-1). These results are consistent with the higher concentrations of hydrogen peroxide found in the higher frequency system and an expected oxidation of EDTA in bulk solution. The presence of a chelated metal decreased the rate of degradation at both frequencies. Cr(III)-EDTA degraded the slowest, supporting the theory that the extremely slow ligand exchange rate of chromium is the determining factor in how fast degradation by hydroxyl radical can occur. The 354-kHz system showed a 17% decrease in the original 150-microM Cr(III)-EDTA complex after 3 h of sonication. All of the chromium from the degraded EDTA complex existed as a combination of oxidized Cr(VI) and possibly small amounts of a new Cr(III)-organic complex (Cr(III)-Y). The 20-kHz system showed a similar extent of degradation (16%) after 3 h of sonication, despite lower hydroxyl radical production. Fifty percent of the chromium from the degraded EDTA complex was found as free Cr3+ ion, with the remaining 50% existing as both Cr(III)-Y and Cr(VI). Varying degrees of bulk oxidation, near-bubble thermolysis, and perhaps different degradation pathways at the two frequencies are responsible for these differences. PMID:14509702

  19. 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

  20. Photoacoustic spectral studies on lanthanide amino acid complexes

    NASA Astrophysics Data System (ADS)

    Yang, Yue-tao; Zhao, Gui-wen; Zhang, Shu-yi

    2003-01-01

    Several kinds of lanthanide complexes with glycine, alanine, phenylalanine, and tryptophan were synthesized and their photoacoustic (PA) spectra were measured. For the complexes of weakly fluorescent lanthanide ions with amino acids, the PA spectra reflect the influences of the ligands on the energy levels of lanthanide ions, whereas for the complexes of fluorescent lanthanide ions with amino acids, the PA spectra can be used to study the energy transfer from aromatic amino acids to lanthanide ions. At last, separating the overlapping peaks of lanthanide complex with tryptophan using the PA phase resolved method is introduced.

  1. The potential role of NaFeEDTA as an iron fortificant.

    PubMed

    Bothwell, Thomas H; MacPhail, A Patrick

    2004-11-01

    Ethylene diamine tetraacetic acid (EDTA) is a hexadentate chelator, which can combine with virtually every metal in the periodic table. CaNa2EDTA and Na2EDTA (ADI 2.5 mg EDTA/kg body weight/day) are widely used as sequestering agents in canned products, while NaFeEDTA is a promising iron fortificant. Binding of EDTA with iron is favored in the acid milieu of the stomach, irrespective of whether the EDTA is administered as CaNa2EDTA, Na2EDTA, or NaFeEDTA, but in the more alkaline medium of the duodenum the iron is exchanged, in part, with other metals. The iron released from EDTA is absorbed by the normal physiological mechanisms. When NaFeEDTA is present in a meal, the iron moiety exchanges with the intrinsic food iron and the EDTA partially protects the iron in this common non-heme iron pool from the effects of inhibitors of iron absorption, such as phytates and polyphenols. When iron is added as NaFeEDTA to an inhibitory meal, it is two to three times better absorbed than is iron added as ferrous sulfate. It also has a similar effect on the intrinsic food iron in the meal. Fortification with NaFeEDTA is most efficacious when administered with cereal- and legume-based diets but offers no advantages over other fortificants when added to meals of high bioavailability. Its potential as a fortificant has been confirmed in five extended fortification trials carried out in developing countries. There is no evidence that NaFeEDTA in the dose range proposed for food fortificants (5 to 10 mg iron daily) will have any direct toxic effects. Na2EDTA and CaNa2EDTA have proved safe over a number of years, while the Joint FAO/WHO Expert Committee on Food Additives concluded in 1999 that NaFeEDTA "could be considered safe when used in supervised fortification programs". Animal and human studies, including the results of two fortification trials, suggest that NaFeEDTA has little or no effect on overall zinc metabolism. Indeed, if anything, it increases zinc and possibly copper

  2. Modulation of matrix metalloproteinase activity by EDTA prevents posterior capsular opacification

    PubMed Central

    Guha, Rajdeep; Jongkey, Geram; Palui, Himangshu; Mishra, Akhilesh; Vemuganti, Geeta K.; Basak, Samar K.; Mandal, Tapan Kumar; Konar, Aditya

    2012-01-01

    Purpose To evaluate the effect of ethylenediaminetetraacetic acid (EDTA) on posterior capsular opacification (PCO) of rabbits and to assess its effect on intraocular tissues. Methods Modulation of matrix metalloproteinase (MMP) activity in the aqueous following cataract surgery in rabbits and its prevention by different doses of EDTA was determined by zymography. For evaluation of PCO, lensectomized rabbits were intracamerally injected with single dose of either 5 mg EDTA or normal saline. After one month, the degree of PCO was determined by slitlamp biomicroscopy, Miyake-Apple view, and histology of the lens capsule. The effect of EDTA on intra ocular pressure (IOP), corneal endothelial cells, and the retina was evaluated by tonometry, specular microscopy and scanning electron microscopy, and electroretinography. The concentration of EDTA in the aqueous was determined by high performance liquid chromatography (HPLC) at different time points. Results The MMP activity was significantly increased in the aqueous of the operated eyes, and EDTA reduced the degree of increase in a dose-dependent manner. EDTA treatment significantly reduced the degree of PCO (p<0.05). Histopathology of the lens capsule showed a reduction in the number of proliferating and migrating cells as well as MMP2 expression in the EDTA-treated eyes. EDTA treatment did not change the IOP; density, morphology and ultrastructure of the corneal endothelial cells; and electroretinography (ERG). EDTA was detectable in the aqueous humor up to 72 h following a single intracameral injection. Conclusions EDTA reduces the degree of PCO by suppressing the MMP activity and it is not toxic to intra ocular structures at the concentration used. PMID:22815623

  3. 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

  4. Transient appearance of postoperative EDTA-dependent pseudothrombocytopenia in a patient after gastrectomy.

    PubMed

    Wenzel, Folker; Lasshofer, Roland; Rox, Jutta; Fischer, Johannes; Giers, Günther

    2011-01-01

    Ethylenediaminetetraacetic acid-dependent pseudothrombocytopenia (EDTA-PTCP) is a well known phenomenon. Antiplatelet antibodies cause platelet clumping in EDTA anticoagulated blood samples, and blood count analysers calculate a spurious low platelet count. We describe a case of a transient appearance of EDTA-PTCP in a patient after gastrectomy. A 58-year-old man underwent partial gastrectomy in for gastric cancer. Preoperatively, his platelet count was in a normal range, and the surgical procedure was performed without bleeding complications. At day 10 after surgery the patient showed a low platelet count, which could be identified as EDTA-PTCP. The phenomenon disappeared in a following postoperative time interval of 2 months. In cases of recently occurring thrombocytopenias EDTA-PTCP should always be considered as a possible cause of low platelet count, in particular in cases of inconspicuous clinical findings. Appropriate laboratory analysis should be applied. PMID:20942597

  5. 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. PMID:25698260

  6. 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.

  7. EDTA enhances lead uptake and facilitates phytoremediation by vetiver grass.

    PubMed

    Gupta, Deepak Kumar; Srivastava, Alok; Singh, V P

    2008-11-01

    Vetiver grass (Vetiveria zizanioides) has strong and dense root system and is a potential phytoremediator plant since it can tolerate a wide range of climatic conditions and grow well in soils contaminated with heavy metals. Soil was artificially contaminated by lead (20 mgl(-1)) during field trials. Four concentration of EDTA (Ethylene diamine tetra acetic acid-disodium salt) solution i.e. 0, 3, 5 and 10 mmol kg(-1) were added to soil prior to harvesting, to study the influence of EDTA solution on phytostabilization by vetiver grass. Results showed that the concentration of lead in roots of vetiver is significantly increased after EDTA solution (5 mmol kg(-1)) application. However, high concentration of EDTA (10 mmol kg(-1)) does not show such significant increase. The toxicity of highly contaminating metal did not affect the growth of vetiver grass significantly but a slight decrease in parameters studied was noticed. No stress symptoms were observed in vetiver plants. Results of present study reveal that vetiver could be considered as a potential phytoremediator for lead contamninated site. PMID:19297989

  8. Starch-lipid complexes: Interesting material and applications from amylose-fatty acid salt inclusion complexes

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Aqueous slurries of high amylose starch can be steam jet cooked and blended with aqueous solutions of fatty acid salts to generate materials that contain inclusion complexes between amylose and the fatty acid salt. These complexes are simply prepared on large scale using commercially available steam...

  9. Pb (II) removal from aqueous media by EDTA-modified mesoporous silica SBA-15.

    PubMed

    Huang, Jin; Ye, Meng; Qu, Yuqi; Chu, Lianfeng; Chen, Rui; He, Qizhuang; Xu, Dongfang

    2012-11-01

    An organic-inorganic hybrid mesoporous silica material was synthesized by two-step post-grafting method of SBA-15 with 3-aminopropyltrimethoxy-silane (APTES) and thionyl dichloride (SOCl(2)) activated ethylenediaminetetraacetic acid (EDTA) in sequence and measured by means of Fourier transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD), elemental analysis (EA), transmission electron microscopy (TEM), nitrogen (N(2)) adsorption-desorption analysis and back titration. The material was found having the beneficial properties of mesoporous silica SBA-15 and EDTA. Adsorption potential of the material for Pb (II) removal from aqueous solution was investigated by varying experimental conditions such as pH, contact time and initial metal concentration. The removal efficiency of Pb(2+) was high under studied experimental conditions. The adsorption equilibrium could be reached within 20 min and the kinetic data were fitted well by pseudo-second-order and intraparticle diffusion model. The adsorbent exhibited a favorable performance and its maximum adsorption capacity calculated by the Langmuir model was 273.2 mg g(-1). Recycling experiments showed the adsorbent could be regenerated by acid treatment without altering its properties. The chemical states of the elements involved in the adsorption were analyzed by X-ray photoelectron spectroscopy (XPS). The results demonstrated that the adsorption mechanism of the material involved Na Pb ion-exchange and carboxyl group dominated surface complexation. PMID:22874637

  10. 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

  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. PMID:24076482

  12. 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.

  13. Nanoscale zero-valent iron for the removal of Zn2+, Zn(II)-EDTA and Zn(II)-citrate from aqueous solutions.

    PubMed

    Kržišnik, Nina; Mladenovič, Ana; Škapin, Andrijana Sever; Škrlep, Luka; Ščančar, Janez; Milačič, Radmila

    2014-04-01

    The parameters which influence the removal of different zinc (Zn) species: Zn(2+), Zn(II)-EDTA and Zn(II)-citrate from aqueous solutions by nanoparticles of zero-valent iron (nZVI) were investigated at environmental relevant pH values. Untreated, surface modified and silica-fume supported nZVI were applied at different iron loads and contact times to Zn solutions, which were buffered to pH 5.3, 6.0 and 7.0. The results revealed that pH, the type of nZVI, the iron load, the contact time, and the Zn species all had a significant influence on the efficiency of removal. Zn(2+), Zn(II)-EDTA and Zn(II)-citrate were the most effectively removed from aqueous solutions by untreated nZVI. Zn(2+) removal was governed mainly by adsorption onto precipitated iron oxides. Complete removal of Zn(2+) and Zn(II)-citrate was obtained at all pH values investigated. The removal of strong Zn(II)-EDTA complex was successful only at acidic pH, which favored degradation of Zn(II)-EDTA. Consequently, the released Zn(2+) was completely removed from the solution by adsorption onto iron oxides. PMID:24463023

  14. Modeling the transport of metals with rate-limited EDTA-promoted extraction and dissolution during EDTA-flushing of copper-contaminated soils.

    PubMed

    Tsang, Daniel C W; Lo, Irene M C; Chan, K L

    2007-05-15

    EDTA-flushing of artificially contaminated soils enhanced Cu extraction but also induced mineral dissolution simultaneously. The mobilization and transport of these metal-EDTA complexes was investigated with column experiments. A quantitative transport model was proposed for simulating the experimental breakthrough curves of Cu, Fe, Al, and Ca. The rate-limited EDTA-promoted extraction and dissolution could be described by respective second-order kinetic terms, which were necessary for explaining the time-dependent depletion of extractable metals (sorbed and indigenous) in soils with continuous EDTA-flushing. Simultaneous simulation of extraction of sorbed Cu and dissolution of soil Fe, Al, and Ca is more conceptually accurate than individual modeling of each metal because the latter approach tends to overestimate the concentration of free EDTA during transport and thus underestimate the rate coefficients of EDTA-promoted dissolution. The fitted rate coefficients of Cu were about an order of magnitude larger than those of Fe and Al; these values probably reflect Cu extraction from weakly sorbed fractions and Fe and Al dissolution from amorphous oxides. The apparent retardation of Fe, Al, and Ca transport had to be taken into account by empirical determination, which was attributed to the metal lability in soils and thermodynamics of surface complexation. PMID:17547193

  15. PHOTOLYSIS OF COPPER(II)-AMINO ACID COMPLEXES IN WATER

    EPA Science Inventory

    Kinetics of the photolysis of Cu2+-amino acid complexes were investigated under sunlight or monochromatic radiation. nder sunlight (latitude 40 degrees N) in the absence of dioxygen, the mean half-lives estimated for the photoreduction of the bis-Cu2+ complexes (CuL2) at pH 8.0 a...

  16. 21 CFR 573.360 - Disodium EDTA.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ..., FEEDS, AND RELATED PRODUCTS FOOD ADDITIVES PERMITTED IN FEED AND DRINKING WATER OF ANIMALS Food Additive Listing § 573.360 Disodium EDTA. The food additive disodium EDTA (disodium ethylenediaminetetraace- tate... food additive contains a minimum of 99 percent disodium ethylenediaminetetraacetate...

  17. 21 CFR 573.360 - Disodium EDTA.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ..., FEEDS, AND RELATED PRODUCTS FOOD ADDITIVES PERMITTED IN FEED AND DRINKING WATER OF ANIMALS Food Additive Listing § 573.360 Disodium EDTA. The food additive disodium EDTA (disodium ethylenediaminetetraace- tate... food additive contains a minimum of 99 percent disodium ethylenediaminetetraacetate...

  18. 21 CFR 573.360 - Disodium EDTA.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ..., FEEDS, AND RELATED PRODUCTS FOOD ADDITIVES PERMITTED IN FEED AND DRINKING WATER OF ANIMALS Food Additive Listing § 573.360 Disodium EDTA. The food additive disodium EDTA (disodium ethylenediaminetetraace- tate... food additive contains a minimum of 99 percent disodium ethylenediaminetetraacetate...

  19. 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.

  20. Polymeric complexes of isonicotinic acid hydrazide with antituberculosis effects.

    PubMed

    Slivkin, A I; Lapenko, V L; Bychuk, A I; Suslina, S N; Slivkin, D A; Kornienko, S V; Belenova, A S

    2013-10-01

    We studied the effects of an analogue of isonicotinic acid hydrazide on the treatment course of experimental tuberculosis. Complex analysis has demonstrated the efficiency of isonicotinic acid hydrazide immobilized on a carrier that consisted of water-soluble cation-active analogue of chitosan (N-chlorohydroxypropyl chitosan) in a complex with cobalt ions in the therapy of experimental tuberculosis. Immunostimulating activity of the polymeric metal complex was revealed. The obtained data can be used for the development of highly effective methods for tuberculosis treatment. PMID:24288761

  1. Improved thermodynamic model for interaction of EDTA with trivalent actinides and lanthanide to ionic strength of 6.60 m

    NASA Astrophysics Data System (ADS)

    Thakur, Punam; Xiong, Yongliang; Borkowski, Marian; Choppin, Gregory R.

    2014-05-01

    The dissociation constants of ethylenediaminetetraacetic acid (H4EDTA), and the stability constants of Am3+, Cm3+and Eu3+ with EDTA4- have been determined at 25 °C, over a range of concentration varying from 0.1 to 6.60 m NaClO4 using potentiometric titration and an extraction technique, respectively. The formation of only 1:1 complex, M(EDTA)-, where (M = Am3+, Cm3+ and Eu3+), was observed under the experimental conditions. The observed ionic strength dependencies of the dissociation constants and the stability constants have been described successfully over the entire ionic strength range using the Pitzer model. The thermodynamic stability constant: logβ1010=20.55±0.18 for Am3+, logβ1010=20.43±0.20 for Cm3+ and logβ1010=20.65±0.19 for Eu3+ were calculated by extrapolation of data to zero ionic strength in an NaClO4 medium. In addition, logβ1010 of 20.05 ± 0.40 for Am3+ was obtained by simultaneously modeling data both in NaCl and NaClO4 media. For all stability constants, the Pitzer model gives an excellent representation of the data using interaction parameters β(0), β(1), and Cϕ determined in this work. The improved model presented in this work would enable researchers to model accurately the potential mobility of actinides (III) and light rare earth elements to ionic strength of 6.60 m in low temperature environments in the presence of EDTA.

  2. Pseudothrombocytopenia secondary to the effects of EDTA in a dog.

    PubMed

    Wills, Tamara B; Wardrop, K Jane

    2008-01-01

    Pseudothrombocytopenia (PTCP) secondary to the effects of ethylenediaminetetraacetic acid (EDTA) has been noted in horses and pigs and should be considered in dogs with moderate thrombocytopenia and no clinical bleeding tendency. This type of pseudothrombocytopenia is not a pathological process by itself, but it can be clinically significant if diagnostics and medical treatments are initiated based on the reported thrombocytopenia. Platelet clumping occurs with EDTA-dependent PTCP, resulting in inaccurate hematology analyzer platelet concentrations. A nontraumatic venipuncture may be sufficient to obtain an accurate platelet count. However, rare cases in the dog may require blood drawn into a different anticoagulant, such as sodium citrate, to help discriminate a true thrombocytopenia from PTCP. PMID:18316447

  3. 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.

  4. 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.

  5. 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. PMID:26499324

  6. 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. PMID:23380448

  7. Effect of EDTA with and without surfactants or ultrasonics on removal of smear layer.

    PubMed

    Lui, Jeen-Nee; Kuah, Hong-Guan; Chen, Nah-Nah

    2007-04-01

    This study compared the in vitro efficacy of Smear Clear (Sybron Endo, CA), a 17% ethylenediaminetetraacetic acid (EDTA) solution with surfactants, to 17% EDTA, with and without the use of ultrasonics, in removal of the smear layer. Seventy-five extracted teeth, randomly distributed into 5 test groups, were prepared by using ProFile rotary instruments (Dentsply Maillefer, Ballaigues, Switzerland) and subjected to different final irrigating regimes; group A, 1% sodium hypochlorite; group B, 17% EDTA; group C, 17% EDTA with ultrasonics; group D, Smear Clear; and group E, Smear Clear with ultrasonics. Samples were examined under the scanning electron microscope and scored for debris and smear layer removal. Statistical analysis showed that groups D and E did not perform significantly better than groups B and C. Group C performed significantly better than group B. Addition of surfactants to EDTA in Smear Clear did not result in better smear layer removal. The use of ultrasonics with 17% EDTA improved smear layer removal. PMID:17368342

  8. The Exocyst Complex Regulates Free Fatty Acid Uptake by Adipocytes

    PubMed Central

    Inoue, Mayumi; Akama, Takeshi; Jiang, Yibin; Chun, Tae-Hwa

    2015-01-01

    The exocyst is an octameric molecular complex that drives vesicle trafficking in adipocytes, a rate-limiting step in insulin-dependent glucose uptake. This study assessed the role of the exocyst complex in regulating free fatty acid (FFA) uptake by adipocytes. Upon differentiating into adipocytes, 3T3-L1 cells acquire the ability to incorporate extracellular FFAs in an insulin-dependent manner. A kinetic assay using fluoresceinated FFA (C12 dodecanoic acid) uptake allows the real-time monitoring of FFA internalization by adipocytes. The insulin-dependent uptake of C12 dodecanoic acid by 3T3-L1 adipocytes is mediated by Akt and phosphatidylinositol 3 (PI3)-kinase. Gene silencing of the exocyst components Exo70 and Sec8 significantly reduced insulin-dependent FFA uptake by adipocytes. Consistent with the roles played by Exo70 and Sec8 in FFA uptake, mCherry-tagged Exo70 and HA-tagged Sec8 partially colocalize with lipid droplets within adipocytes, suggesting their active roles in the development of lipid droplets. Tubulin polymerization was also found to regulate FFA uptake in collaboration with the exocyst complex. This study demonstrates a novel role played by the exocyst complex in the regulation of FFA uptake by adipocytes. PMID:25768116

  9. Transition metal complexes of isonicotinic acid (2-hydroxybenzylidene)hydrazide.

    PubMed

    Abou-Melha, Khlood S

    2008-06-01

    A new series of transition metal complexes of Schiff base isonicotinic acid (2-hydroxybenzylidene)hydrazide, HL, have been synthesized. The Schiff base reacted with Cu(II), Ni(II), Co(II), Mn(II), Fe(III) and UO2(II) ions as monobasic tridentate ligand to yield mononuclear complexes of 1:2 (metal:ligand) except that of Cu(II) which form complex of 1:1 (metal:ligand). The ligand and its metal complexes were characterized by elemental analyses, IR, UV-vis, mass and 1H NMR spectra, as well as magnetic moment, conductance measurements, and thermal analyses. All complexes have octahedral configurations except Cu(II) complex which has an extra square planar geometry distorted towards tetrahedral. While, the UO2(II) complex has its favour hepta-coordination. The ligand and its metal complexes were tested against one strain Gram +ve bacteria (Staphylococcus aureus), Gram -ve bacteria (Escherichia coli), and Fungi (Candida albicans). The tested compounds exhibited higher antibacterial activities. PMID:17728178

  10. Transition metal complexes of isonicotinic acid (2-hydroxybenzylidene)hydrazide

    NASA Astrophysics Data System (ADS)

    Abou-Melha, Khlood S.

    2008-06-01

    A new series of transition metal complexes of Schiff base isonicotinic acid (2-hydroxybenzylidene)hydrazide, HL, have been synthesized. The Schiff base reacted with Cu(II), Ni(II), Co(II), Mn(II), Fe(III) and UO 2(II) ions as monobasic tridentate ligand to yield mononuclear complexes of 1:2 (metal:ligand) except that of Cu(II) which form complex of 1:1 (metal:ligand). The ligand and its metal complexes were characterized by elemental analyses, IR, UV-vis, mass and 1H NMR spectra, as well as magnetic moment, conductance measurements, and thermal analyses. All complexes have octahedral configurations except Cu(II) complex which has an extra square planar geometry distorted towards tetrahedral. While, the UO 2(II) complex has its favour hepta-coordination. The ligand and its metal complexes were tested against one strain Gram +ve bacteria ( Staphylococcus aureus), Gram -ve bacteria (Escherichia coli) , and Fungi ( Candida albicans). The tested compounds exhibited higher antibacterial activities.

  11. 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

  12. Migration of radioactive wastes: radionuclide mobilization by complexing agents.

    PubMed

    Means, J L; Crerar, D A; Duguid, J O

    1978-06-30

    Ion exchange, gel filtration chromatography, and gas chromatographymass spectrometry analyses have demonstrated that ethylenediaminetetraacetic acid (EDTA), an extremely strong complexing agent commonly used in decontamination operations at nuclear facilities, is causing the low-level migration of cobalt-60 from intermediate-level liquid waste disposal pits and trenches in the Oak Ridge National Laboratory burial grounds. Because it forms extremely strong complexes with rare earths and actinides, EDTA or similar chelates may also be contributing to the mobilization of these radionuclides from various terrestrial radioactive waste burial sites around the country. PMID:17757689

  13. 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.

  14. Effect of inclusion complex on nitrous acid reaction with flavonoids

    NASA Astrophysics Data System (ADS)

    Khalafi, Lida; Rafiee, Mohammad; Sedaghat, Sajjad

    2011-10-01

    The kinetic of the nitrous acid reactions with quercetin and catechin has been studied using spectrophotometric method in aqueous solution. The results show that these antioxidants participate in oxidation reactions with nitrous acid which is derived from protonation of nitrite ion in mild acidic conditions. Corresponding o-quinones as relatively stable products were detected by spectrophotometric techniques. pH dependence of the reactions has been examined and the rate constants of reactions were obtained by non-linear fitting of kinetic profiles. The effect of β-cyclodextrin on the oxidation pathway was another object of this study. It is shown that β-cyclodextrin has an inhibitory effect on the oxidation reaction. The rate constants of oxidation reactions for complexed forms and their stability constants were obtained based on changes in the reaction rates as a function of β-cyclodextrin concentration.

  15. 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.

  16. 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

  17. Application of EDTA decontamination on soils affected by mining activities and impact of treatment on the geochemical partition of metal contaminants.

    PubMed

    Xia, Wenbin; Gao, Hui; Wang, Xianhai; Zhou, Chunhua; Liu, Yunguo; Fan, Ting; Wang, Xin

    2009-05-30

    Two soil samples were collected at mining areas located in southern Hunan Province, China. EDTA extraction of Pb, Zn, Cu and Cd from these two tailing soils was studied using column leaching experiments. The redistributions of heavy metals (HMs) were determined using the modified BCR (Community Bureau of Reference) sequential extraction procedure, before and after EDTA extraction. The results indicated that EDTA was an effective extractant because of its strong chelating ability for various HMs. The proportions of Pb, Zn, Cu and Cd in the four fractions varied largely after EDTA extraction. The extraction efficiency of EDTA of the acid-extractable fraction (AEX) was significant in shallow soil column, while in deeper soil column, decrease of the extraction efficiency of reduced (RED), oxidizable (OX) and residual fractions (RES) was obtained, which was mainly due to the decrease of EDTA concentration. PMID:18838220

  18. 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.

  19. 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

  20. Polyacrylic acids-bovine serum albumin complexation: Structure and dynamics.

    PubMed

    Othman, Mohamed; Aschi, Adel; Gharbi, Abdelhafidh

    2016-01-01

    The study of the mixture of BSA with polyacrylic acids at different masses versus pH allowed highlighting the existence of two regimes of weak and strong complexation. These complexes were studied in diluted regime concentration, by turbidimetry, dynamic light scattering (DLS), zeta-potential measurements and nuclear magnetic resonance (NMR). We have followed the pH effect on the structure and properties of the complex. This allowed refining the interpretation of the phase diagram and understanding the observed phenomena. The NMR measurements allowed probing the dynamics of the constituents versus the pH. The computational method was used to precisely determine the electrostatic potential of BSA and how the polyelectrolyte binds to it at different pH. PMID:26478316

  1. [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

  2. 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.

  3. Growth parameters of escherichia coli O157:H7, salmonella and listeria monocytogenes and aerobic mesophilic bacteria of apple cider amended with nisin-EDTA

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The effect of nisin (0 or 300 IU), Ethylenediamine Tetraacetic Acid (EDTA, 20 mM) and (nisin 300 IU+ EDTA 20 mM) on growth parameters; including lag period (LP) and growth rate (GR) of Escherichia coli O157:H7, L. monocytogenes and Salmonella spp. in the presence or absence of aerobic mesophilic bac...

  4. Protic acid-fluorine interactions and reactions with acids of transition metal perfluoroalkyl and perfluoroolefin complexes

    SciTech Connect

    Barmore, R.M.; Richmond, T.G.

    1993-12-31

    The authors are interested in devising new methods of C-F and C-X bond activation which could be applied to destruction of environmentally significant molecules. Dihalocarbene complexes are thought to be intermediates in a variety of reactions of metal haloalkyl complexes which could be applied to this problem. This paper reports observations indicating initial interactions of protic acids and fluorocarbon complexes which can be applied toward the hydrolysis of C-F bonds. Reactions of long chain halocarbons and halolefins will also be discussed.

  5. 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.

  6. 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

  7. Synthesis and characterization of europium- trimesic acid luminescent complex nanorods

    NASA Astrophysics Data System (ADS)

    Ren, Huijuan; Liu, Guixia; Song, Xinyuan; Hong, Guangyan; Cui, Zhenfeng

    2006-01-01

    Eu(III)-trimesic acid (TMA) luminescent complex Nanorods were synthesized in the polyvinylpyrrolidone matrix. The obtained sample was characterized by elemental analysis, Inductively Coupled Plasma-atomic emission spectroscopy(ICP-AES), X-ray diffraction(XRD), Fourier-transform Infrared spectroscopy(FT-IR), transmission electron microscopy(TEM) and photoluminescence spectra (PL). The results demonstrated that its chemical constitution is PVP/Eu(MTA) • 2H IIO. The XRD patterns show that the complex was a new kind of crystal whose structure is totally different with the ligand. TEM image indicated that the complex is nanocrystal with rod shape in one dimension, the size of rod diameter is about 50~100 nm, and the length ranges from hundred nanometer to a few micrometers, in addition, the dispersity is better. Photoluminescence analysis indicated that the complex emits Eu 3+ characteristic luminescence under ultraviolet excitation. TG-DTA curves indicated that the complex is heat stable under the temperature of 454°C. Therefore an thermal decomposition mechanism is: Eu(MTA) • 2H IIO->Eu(MTA)-> Eu IIO 3.

  8. 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, FEEDS, AND RELATED PRODUCTS FOOD ADDITIVES PERMITTED IN FEED AND DRINKING WATER OF ANIMALS Food...

  9. Cloning, Sequencing, and Characterization of a Gene Cluster Involved in EDTA Degradation from the Bacterium BNC1

    PubMed Central

    Bohuslavek, Jan; Payne, Jason W.; Liu, Yong; Bolton, Harvey; Xun, Luying

    2001-01-01

    EDTA is a chelating agent, widely used in many industries. Because of its ability to mobilize heavy metals and radionuclides, it can be an environmental pollutant. The EDTA monooxygenases that initiate EDTA degradation have been purified and characterized in bacterial strains BNC1 and DSM 9103. However, the genes encoding the enzymes have not been reported. The EDTA monooxygenase gene was cloned by probing a genomic library of strain BNC1 with a probe generated from the N-terminal amino acid sequence of the monooxygenase. Sequencing of the cloned DNA fragment revealed a gene cluster containing eight genes. Two of the genes, emoA and emoB, were expressed in Escherichia coli, and the gene products, EmoA and EmoB, were purified and characterized. Both experimental data and sequence analysis showed that EmoA is a reduced flavin mononucleotide-utilizing monooxygenase and that EmoB is an NADH:flavin mononucleotide oxidoreductase. The two-enzyme system oxidized EDTA to ethylenediaminediacetate (EDDA) and nitrilotriacetate (NTA) to iminodiacetate (IDA) with the production of glyoxylate. The emoA and emoB genes were cotranscribed when BNC1 cells were grown on EDTA. Other genes in the cluster encoded a hypothetical transport system, a putative regulatory protein, and IDA oxidase that oxidizes IDA and EDDA. We concluded that this gene cluster is responsible for the initial steps of EDTA and NTA degradation. PMID:11157232

  10. [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

  11. 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.

  12. The biological activities of protein/oleic acid complexes reside in the fatty acid.

    PubMed

    Fontana, Angelo; Spolaore, Barbara; Polverino de Laureto, Patrizia

    2013-06-01

    A complex formed by human α-lactalbumin (α-LA) and oleic acid (OA), named HAMLET, has been shown to have an apoptotic activity leading to the selective death of tumor cells. In numerous publications it has been reported that in the complex α-LA is monomeric and adopts a partly folded or "molten globule" state, leading to the idea that partly folded proteins can have "beneficial effects". The protein/OA molar ratio initially has been reported to be 1:1, while recent data have indicated that the OA-complex is given by an oligomeric protein capable of binding numerous OA molecules per protein monomer. Proteolytic fragments of α-LA, as well as other proteins unrelated to α-LA, can form OA-complexes with biological activities similar to those of HAMLET, thus indicating that a generic protein can form a cytotoxic complex under suitable experimental conditions. Moreover, even the selective tumoricidal activity of HAMLET-like complexes has been questioned. There is recent evidence that the biological activity of long chain unsaturated fatty acids, including OA, can be ascribed to their effect of perturbing the structure of biological membranes and consequently the function of membrane-bound proteins. In general, it has been observed that the cytotoxic effects exerted by HAMLET-like complexes are similar to those reported for OA alone. Overall, these findings can be interpreted by considering that the protein moiety does not have a toxic effect on its own, but merely acts as a solubilising agent for the inherently toxic fatty acid. PMID:23499846

  13. 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.

  14. 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

  15. 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

  16. Occult breast cancer with EDTA-dependent pseudothrombocytopenia -a case report-.

    PubMed

    Abe, Hajime; Shimizu, Tomoharu; Cho, Hirotomi; Kubota, Yoshihiro; Umeda, Tomoko; Kurumi, Yoshimasa; Tani, Tohru

    2010-05-01

    A case of occult breast cancer with pseudothrombocytopenia (PTCP) is reported. A 50-year-old woman was consulted with a left axillary tumor. Ductal carcinoma was found by the core needle biopsy, and no primary lesion was detected. Her preoperative platelet count, obtained from an ethylene diamine tetraacetic acid (EDTA) sampling bottle, was 3.1 x 10(4) per mL, but she had no history of bleeding problems. A heparinized blood sample showed a normal platelet count of 390 x 10(4) per mL. These findings suggested a diagnosis of occult breast cancer with EDTA-dependent PTCP, and level II axillary lymph node dissection was performed. She received adjuvant chemotherapy and radiotherapy, but she died 2 years and 5 months after the surgery because of lung and brain metastases. Awareness of the phenomenon and knowledge of the underlying physiological principles will enable surgeons to manage patients with EDTA-dependent PTCP appropriately. PMID:20495328

  17. 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. PMID:26364188

  18. 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. PMID:26297199

  19. 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

  20. 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

  1. [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

  2. Immobilization of the [RuII(edta)NO+] Ion on the surface of functionalized silica gel.

    PubMed

    Zanichelli, Patrícia G; Sernaglia, Rosana L; Franco, Douglas W

    2006-01-01

    The reaction of NO and the immobilized dimer complex (edta)(2)Ru(2)(III(1/2),III(1/2)) on silica gel chemically modified with [3-(2-aminoethyl)aminopropyl]trimethoxysilane (AEATS) produces the corresponding immobilized nitrosyl complex AEATS/Ru(II)NO(+). This compound, a monomer, was obtained by reducing the immobilized ruthenium dimer either electrochemically or with Eu(II) and reacting this species with NO(2)(-) ions. The properties of [Ru(edta)NO](-) in solution and anchored (AEATS/Ru(II)NO(+)) on silica were compared using electrochemical (DPV, CV) and spectroscopic (IR, UV-vis, and ESR) techniques. The results indicate that immobilization does not alter the reactivity of the ruthenium complex and confirm that [Ru(edta)(H(2)O)](2)(-) may be used, either in solution or immobilized, as a catalyst for the conversion of NO(2)(-) to NO(+). Both the anchored nitrosyl complex AEATS/Ru(II)NO(+) and the [Ru(edta)NO](-) species in solution, upon one-electron reduction, liberate NO at comparable rates. PMID:16378421

  3. 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

  4. 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.

  5. [EDTA-dependent pseudothrombocytopenia: clinical aspects and laboratory tests].

    PubMed

    Saigo, Katsuyasu; Sakota, Yasuyuki; Masuda, Yukako

    2005-07-01

    EDTA-dependent pseudothrombocytopenia (EDTA-PTCP) is a phenomenon caused by EDTA-dependent anti-platelet antibody. This antibody induces platelet agglutination in vitro, resulting in a decrease in platelet counts. It is necessary for clinicians to consider the possible presence of PTCP in cases of patients having low platelet counts without any hemorrhagic tendency. In this article, we describe some aspects of EDTA-PTCP including, (1) characteristics of platelet agglutination, (2)possible mechanisms for antibody production, (3) several methods to determine the true platelet number, and also (4) a few similar phenomena induced by antibodies independent of EDTA. PMID:16104534

  6. 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

  7. 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

  8. A combined spectrophotometric-AAS method for the analysis of trace metal, EDTA, and metal-EDTA mixture solutions in adsorption modeling experiments.

    PubMed

    Güçlü, K; Hugül, M; Demirci-Cekiç, S; Reşat; Apak

    2000-10-01

    The adsorption of free- and bound-metal ions (metal complexes) as well as of ligands onto various hydrous oxide type sorbents have been extensively modelled using EDTA as the model ligand. This type of modelling uses metal ion-EDTA mixture solutions containing stoichiometrically equivalent or excessive amounts of either constituent. Consequently, for mixture solutions equilibrated with the sorbent, the aim was to develop a suitable method for determining either metal complex+free ligand (MY(2-)+H(2)Y(2-)) or metal complex+free metal (MY(2-)+M(2+)) in the aqueous filtrate, the metal M being lead or cadmium. The conventional method of analyzing such filtrates is exchanging different metal-EDTA complexes with Fe(NO(3))(3) followed by HPLC using UV detection. The developed method utilizes Vis- and AA-spectrometry widespread in common laboratories, eliminating the need for HPLC and UV techniques that require higher operational cost, expertise and contaminant-free media. The developed procedure is based on the following analyses for the possible constituents of equilibrated solution (with the sorbent). All EDTA (free or bound, as H(2)Y(2-) or MY(2-)) species are converted into FeY(-) by adding Fe(NO(3))(3), and heating at 80 degrees C for 1 h. All metal (free or bound, as M(2+) or MY(2-)) species are determined by AAS. All unbound (free) Fe(3+) species are determined by the thiocyanate spectrophotometric method at 480 nm. Then 'EDTA-bound iron (III)' is defined as added Fe minus colorimetrically (thiocyanate method) found Fe, and 'AAS-found metal' (lead or cadmium) corresponds to M(2+) and/or MY(2-), depending on the analyzed solution. If EDTA-bound Fe(III) is greater than AAS-found metal, then one has a (MY(2-)+H(2)Y(2-)) mixture where AAS-found metal is (MY(2-)), and free EDTA, i.e. (H(2)Y(2-)), is calculated from the difference. If EDTA-bound Fe(III) is smaller than AAS-found metal, then one has a (M(2+)+ MY(2-)) mixture where EDTA-bound Fe(III) is (MY(2-)), and the

  9. 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

  10. 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.

  11. Incorporation of rare-earth ions in Mg-Al layered double hydroxides: intercalation with an [Eu(EDTA)] - chelate

    NASA Astrophysics Data System (ADS)

    Li, Cang; Wang, Ge; Evans, David G.; Duan, Xue

    2004-12-01

    Reaction of an aqueous slurry of an Mg 2Al-NO 3 layered double hydroxide with a four-fold excess of Na[Eu(EDTA)] gives a material which analyses for Mg 0.68Al 0.32(OH) 2[Eu(EDTA)] 0.10(CO 3) 0.11·0.66H 2O. The interlayer spacing of the material is 13.8 Å, corresponding to a gallery height of 9.0 Å, which accords with the maximal dimensions (9-10 Å) of the anion in metal-EDTA complex salts as determined by single crystal X-ray diffraction. Geometrical considerations show that the charge density on the layered double hydroxide layers is too high to be balanced by intercalation of [Eu(EDTA)] - alone, necessitating the co-intercalation of carbonate ions which have a much higher charge density.

  12. 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. PMID:25275874

  13. 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

  14. 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

  15. 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.

  16. 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...

  17. 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...

  18. 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...

  19. 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...

  20. 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...

  1. 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)…

  2. 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.

  3. 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

  4. 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. PMID:25119276

  5. Comparison of the Antimicrobial Properties of Chitosan Oligosaccharides (COS) and EDTA against Fusarium fujikuroi Causing Rice Bakanae Disease.

    PubMed

    Kim, Seung Won; Park, Jae Kweon; Lee, Cho Heun; Hahn, Bum-Soo; Koo, Ja Choon

    2016-04-01

    Bakanae disease is a destructive rice disease in South Korea caused by Fusarium fujikuroi infection. Chemical fungicides have been used to manage the disease, but the emergence of fungicide-resistant strains has gradually increased. Two chelating agents, chitosan oligosaccharides (COS) and ethylenediaminetetraacetatic acid (EDTA), are well known as biosafe and biocompatible antimicrobial agents. In this study, we compared the actions of COS and EDTA to gain a better understanding of the underlying antimicrobial activities and to evaluate them as eco-friendly fungicides against F. fujikuroi. While COS exhibited a rapid fungicidal effect on hyphal growing cells within 5 min, EDTA had a fungistatic effect on reversible growth inhibition. Scanning electron microscopy revealed that COS treatment resulted in pore-formation and cellular leakage along the growing hyphae, whereas EDTA caused no significant morphological changes. COS activity was greatly suppressed by the addition of Ca(2+) to the medium, and EDTA action was largely suppressed by Mn(2+) and slightly by Ca(2+), respectively. Taken together, these results indicated that two chelating agents, COS and EDTA, have different modes of antimicrobial action on F. fujikuroi. Thus, the combination of chelating agents having different modes of action might be an effective disease management strategy to prevent or delay the development of fungicide-resistant strains. PMID:26729353

  6. EDTA-enhanced phytoremediation of contaminated calcareous soils: heavy metal bioavailability, extractability, and uptake by maize and sesbania.

    PubMed

    Suthar, Vishandas; Memon, Kazi Suleman; Mahmood-ul-Hassan, Muhammad

    2014-06-01

    Natural and chemically enhanced phytoextraction potentials of maize (Zea mays L.) and sesbania (Sesbania aculeata Willd.) were explored by growing them on two soils contaminated with heavy metals. The soils, Gujranwala (fine, loamy, mixed, hyperthermic Udic Haplustalf) and Pacca (fine, mixed, hyperthermic Ustollic Camborthid), were amended with varying amounts of ethylenediaminetetraacetic acid (EDTA) chelating agent, at 0, 1.25, 2.5, and 5.0 mM kg(-1) soil to enhance metal solubility. The EDTA was applied in two split applications at 46 and 60 days after sowing (DAS). The plants were harvested at 75 DAS. Addition of EDTA significantly increased the lead (Pb) and cadmium (Cd) concentrations in roots and shoots, uptake, bioconcentration factor, and phytoextraction rate over the control. Furthermore, addition of EDTA also significantly increased the soluble fractions of Pb and Cd in soil over the controls; the maximum increase of Pb and Cd was 13.1-fold and 3.1-fold, respectively, with addition of 5.0 mM EDTA kg(-1)soil. Similarly, the maximum Pb and Cd root and shoot concentrations, translocation, bioconcentration, and phytoextraction efficiency were observed at 5.0 mM EDTA kg(-1) soil. The results suggest that both crops can successfully be used for phytoremediation of metal-contaminated calcareous soils. PMID:24515546

  7. 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

  8. Proton exchange in acid-base complexes induced by reaction coordinates with heavy atom motions

    NASA Astrophysics Data System (ADS)

    Alavi, Saman; Taghikhani, Mahdi

    2012-06-01

    We extend previous work on nitric acid-ammonia and nitric acid-alkylamine complexes to illustrate that proton exchange reaction coordinates involve the rocking motion of the base moiety in many double hydrogen-bonded gas phase strong acid-strong base complexes. The complexes studied involve the biologically and atmospherically relevant glycine, formic, acetic, propionic, and sulfuric acids with ammonia/alkylamine bases. In these complexes, the magnitude of the imaginary frequencies associated with the proton exchange transition states are <400 cm-1. This contrasts with widely studied proton exchange reactions between symmetric carboxylic acid dimers or asymmetric DNA base pair and their analogs where the reaction coordinate is localized in proton motions and the magnitude of the imaginary frequencies for the transition states are >1100 cm-1. Calculations on complexes of these acids with water are performed for comparison. Variations of normal vibration modes along the reaction coordinate in the complexes are described.

  9. 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.

  10. 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

  11. Intramolecular deactivation processes in complexes of salicylic acid or glycolic acid with Eu(III)

    NASA Astrophysics Data System (ADS)

    Kuke, S.; Marmodée, B.; Eidner, S.; Schilde, U.; Kumke, M. U.

    2010-04-01

    The complexation of Eu(III) by 2-hydroxy benzoic acid (2HB) or glycolic acid (GL) was investigated using steady-state and time-resolved laser spectroscopy. Experiments were carried out in H 2O as well as in D 2O in the temperature range of 80Kcomplexes was determined. It is stressed that ligand-specific quenching processes (other than OH quenching induced by water molecules) need to be determined and considered in detail, in order to extract speciation-relevant information from luminescence data (e.g., estimation of the number of water molecules nO in the first coordination sphere of Eu(III)). In case of 2HB, conclusions drawn from the evaluation of the Eu(III) luminescence are compared with results of a X-ray structure analysis.

  12. Acid-catalyzed isomerization of rhenium alkyne complexes to rhenium allene complexes via 1-metallacyclopropene intermediates

    SciTech Connect

    Casey, C.P.; Brady, J.T.

    1998-10-12

    The alkyne complexes C{sub 5}Me{sub 5}(CO){sub 2}Re({eta}{sup 2}-MeC{triple_bond}CMe) (1) and C{sub 5}H{sub 5}(CO){sub 2}Re({eta}{sup 2}-MeC{triple_bond}CMe) (6) underwent acid-catalyzed isomerization by way of 1-metallacyclopropene intermediates to form the allene complexes C{sub 5}Me{sub 5}(CO){sub 2}Re({eta}{sup 2}-2,3-MeHC{double_bond}C{double_bond}CH{sub 2}) (5) and C{sub 5}H{sub 5}(CO){sub 2}Re({eta}{sup 2}-2,3-MeHC{double_bond}C{double_bond}CH{sub 2}) (7). Stoichiometric reaction of 1 with CF{sub 3}CO{sub 2}H initially produced the kinetic addition product C{sub 5}Me{sub 5}(CO){sub 2}Re[{eta}{sup 2}-(Z)-MeHC{double_bond}CMeO{sub 2}CCF{sub 3}] (8-Z), which slowly isomerized to the thermodynamically more stable E isomer 8-E. The reaction of 6 with CF{sub 3}CO{sub 2}H at {minus}73 C produced only C{sub 5}H{sub 5}(CO){sub 2}Re[{eta}{sup 2}-(E)-MeHC{double_bond}CMeO{sub 2}CCF{sub 3}] (9-E), which isomerized at -60 C to a 80:20 equilibrium mixture of 9-E and 9-Z. Treatment of 9-E and 9-Z with base led to formation of allene complex 7. The rate of this elimination was independent of base concentration. Labeling studies showed that the 1-metallacyclopropene intermediate C{sub 5}H{sub 5}(CO){sub 2}({eta}{sup 2}-CMeCHMe){sup +}CF{sub 3}CO{sub 2}{sup {minus}} (12-CF{sub 3}CO{sub 2}) undergoes a number of important reactions which include, in order of decreasing relative rates: (1) addition of trifluoroacetate to give enol trifluoroacetate complexes, (2) deprotonation to give complexed allenes, (3) degenerate 1,2-hydride migrations, (4) hydride migrations to give {eta}{sup 3}-allyl complexes, and (5) deprotonation to give complexed alkynes.

  13. Soil Cd availability to Indian mustard and environmental risk following EDTA addition to Cd-contaminated soil.

    PubMed

    Jiang, X J; Luo, Y M; Zhao, Q G; Baker, A J M; Christie, P; Wong, M H

    2003-02-01

    A pot experiment was conducted to investigate the influence of EDTA on the extractability of Cd in the soil and uptake of Cd by Indian mustard (Brassica juncea). Twenty levels of soil Cd concentration ranging from 10 to 200 mg kg(-1) were produced by spiking aliquots of a clay loam paddy soil with Cd(NO3)2. One week before the plants were harvested EDTA was applied to pots in which the soil had been spiked with 20, 40, 60...200 mg Cd kg(-1). The EDTA was added at the rate calculated to complex with all of the Cd added at the 200 mg kg(-1) level. Control pots spiked with 10, 30, 50... 190 mg Cd kg(-1) received no EDTA. The plants were harvested after 42 days' growth. Soil water- and NH4NO3-extractable Cd fractions increased rapidly following EDTA application. Root Cd concentrations decreased after EDTA application, but shoot concentrations increased when the soil Cd levels were >130 mg kg(-1) and Cd toxicity symptoms were observed. The increases in soil solution Cd induced by EDTA did not increase plant total Cd uptake but appeared to stimulate the translocation of the metal from roots to shoots when the plants appeared to be under Cd toxicity stress. The results are discussed in relation to the possible mechanisms by which EDTA may change the solubility and bioavailability of Cd in the soil and the potential for plant uptake and environmental risk due to leaching losses to groundwater. PMID:12688496

  14. Remediation of lead-contaminated soil with EDTA: Batch and column studies

    SciTech Connect

    Heil, D.M.; Samani, Z.; Hanson, A.T.; Hu, S.; Rudd, B.

    1996-12-31

    Chelate extraction using ethylenediaminetetraacetic acid (EDTA) and other chelates has been demonstrated to be an effective method of removal of Pb from many contaminated soils. However, column leaching of Pb from alkaline soils with EDTA has been problematic due to extremely low soil permeability. The purpose of this study was to determine the effect of the addition of KOH and Ca(Cl){sub 2} to K{sub 2}H{sub 2}-EDTA extraction solution on Pb removal and hydraulic conductivity. A Pb-contaminated soil was sampled from an abandoned lead-acid battery recycling facility. Both batch shaker extractions and column leaching experiments were completed using five different EDTA extract solutions. Addition of Ca(Cl){sub 2} only to K{sub 2}H{sub 2}-EDTA did not change the amount of Pb removed by batch extraction, and Pb solubility was only slightly decreased by the addition of both Ca(Cl){sub 2} and KOH. Lead solubility was observed to decrease as pH was increased by the addition of KOH. The amount of time required to leach 6.0 l of extraction solution through the soil columns varied from 2 to 33 days. The addition of Ca(Cl){sub 2} and/or KOH resulted in increased soil hydraulic conductivity. However, Pb removal was diminished with the addition of Ca(Cl){sub 2} and KOH because of decreased Pb solubility and also a shorter residence time of the extract solution in the column. The hydraulic conductivity was related to residual calcium carbonate content, suggesting that dissolution of CaCO{sub 3} and subsequent production of CO{sub 2} gas in soil pores was partially responsible for the observed reductions in soil permeability.

  15. 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. PMID:19282075

  16. 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.

  17. 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).

  18. 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)

  19. 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

  20. 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...

  1. 40 CFR 721.10297 - Tin, C16-18 and C18-unsatd. fatty acids castor-oil fatty acids complexes.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... acids castor-oil fatty acids complexes. 721.10297 Section 721.10297 Protection of Environment.... fatty acids castor-oil fatty acids complexes. (a) Chemical substances and significant new uses subject to reporting. (1) The chemical substance identified as tin, C16-18 and C18-unsatd. fatty acids...

  2. 40 CFR 721.10297 - Tin, C16-18 and C18-unsatd. fatty acids castor-oil fatty acids complexes.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... acids castor-oil fatty acids complexes. 721.10297 Section 721.10297 Protection of Environment.... fatty acids castor-oil fatty acids complexes. (a) Chemical substances and significant new uses subject to reporting. (1) The chemical substance identified as tin, C16-18 and C18-unsatd. fatty acids...

  3. 40 CFR 721.10297 - Tin, C16-18 and C18-unsatd. fatty acids castor-oil fatty acids complexes.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... acids castor-oil fatty acids complexes. 721.10297 Section 721.10297 Protection of Environment.... fatty acids castor-oil fatty acids complexes. (a) Chemical substances and significant new uses subject to reporting. (1) The chemical substance identified as tin, C16-18 and C18-unsatd. fatty acids...

  4. 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. PMID:26974482

  5. Crystal structure of beta-cyclodextrin-benzoic acid inclusion complex.

    PubMed

    Aree, Thammarat; Chaichit, Narongsak

    2003-02-14

    The inclusion complex of beta-cyclodextrin (beta-CD) with benzoic acid (BA) has been characterized crystallographically. Two beta-CDs cocrystallize with two BAs, 0.7 ethanol and 20.65 water molecules [2(C(6)H(10)O(5))(7).2(C(7)H(6)O(2)).0.7(C(2)H(6)O).20.65H(2)O] in the triclinic space group P1 with unit cell constants: a=15.210(1), b=15.678(1), c=15.687(1) A, alpha=89.13(1), beta=74.64(1), gamma=76.40(1) degrees. The anisotropic refinement of 1840 atomic parameters against 16,201 X-ray diffraction data converged at R=0.078. In the crystal lattice, beta-CD forms dimers stabilized by direct O-2(m)_1/O-3(m)_1...O-2(n)_2/O-3(n)_2 hydrogen bonds (intradimer) and by indirect O-6(m)_1...,O-6(n)_2 hydrogen bonds with one or two bridging water molecules joined in between (interdimer). These dimers are stacked like coins in a roll constructing endless channels where the guest molecules are included. The BA molecules protrude with their COOH groups at the beta-CD O-6-sides and are maintained in positions by hydrogen bonding to the surrounding O-6-H groups and water molecules. Water molecules (20.65) are distributed over 30 positions in the interstices between beta-CD molecules, except the water sites W-1, W-2 that are located in the channel of the beta-CD dimer. Water site W-2 is hydrogen bonded to the disordered ethanol molecule (occupancy 0.7). PMID:12559746

  6. Acceleration of the Fe(III)EDTA(-) reduction rate in BioDeNO(x) reactors by dosing electron mediating compounds.

    PubMed

    Maas, Peter van der; Brink, Paula van den; Klapwijk, Bram; Lens, Piet

    2009-04-01

    BioDeNO(x), a novel technique to remove NO(x) from industrial flue gases, is based on absorption of gaseous nitric oxide into an aqueous Fe(II)EDTA(2-) solution, followed by the biological reduction of Fe(II)EDTA(2-) complexed NO to N(2). Besides NO reduction, high rate biological Fe(III)EDTA(-) reduction is a crucial factor for a succesful application of the BioDeNO(x) technology, as it determines the Fe(II)EDTA(2-) concentration in the scrubber liquor and thus the efficiency of NO removal from the gas phase. This paper investigates the mechanism and kinetics of biological Fe(III)EDTA(-) reduction by unadapted anaerobic methanogenic sludge and BioDeNO(x) reactor mixed liquor. The influence of different electron donors, electron mediating compounds and CaSO(3) on the Fe(III)EDTA(-) reduction rate was determined in batch experiments (21mM Fe(III)EDTA(-), 55 degrees C, pH 7.2+/-0.2). The Fe(III)EDTA(-) reduction rate depended on the type of electron donor, the highest rate (13.9mMh(-1)) was observed with glucose, followed by ethanol, acetate and hydrogen. Fe(III)EDTA(-) reduction occurred at a relatively slow (4.1mMh(-1)) rate with methanol as the electron donor. Small amounts (0.5mM) of sulfide, cysteine or elemental sulfur accelerated the Fe(III)EDTA(-) reduction. The amount of iron reduced significantly exceeded the amount that can be formed by the chemical reaction of sulfide with Fe(III)EDTA(-), suggesting that the Fe(III)EDTA(-) reduction was accelerated via an auto-catalytic process with an unidentified electron mediating compound, presumably polysulfides, formed out of the sulfur additives. Using ethanol as electron donor, the specific Fe(III)EDTA(-) reduction rate was linearly related to the amount of sulfide supplied. CaSO(3) (0.5-100mM) inhibited Fe(III)EDTA(-) reduction, probably because SO(3)(2-) scavenged the electron mediating compound. PMID:18561978

  7. Monohydroxamic acids and bridging dihydroxamic acids as chelators to ruthenium(III) and as nitric oxide donors: syntheses, speciation studies and nitric oxide releasing investigations.

    PubMed

    Griffith, Darren; Krot, Krystyna; Comiskey, Jedd; Nolan, Kevin B; Marmion, Celine J

    2008-01-01

    The synthesis and spectroscopic characterisation of novel mononuclear Ru(III)(edta)(hydroxamato) complexes of general formula [Ru(H2edta)(monoha)] (where monoha = 3- or 4-NH2, 2-, 3- or 4-C1 and 3-Me-phenylhydroxamato), as well as the first example of a Ru(III)-N-aryl aromatic hydroxamate, [Ru(H2edta)(N-Me-bha)].H2O (N-Me-bha = N-methylbenzohydroxamato) are reported. Three dinuclear Ru(III) complexes with bridging dihydroxamato ligands of general formula [{Ru(H2edta)}2(mu-diha)] where diha = 2,6-pyridinedihydroxamato and 1,3- or 1,4-benzodihydroxamato, the first of their kind with Ru(III), are also described. The speciation of all of these systems (with the exception of the Ru-1,4-benzodihydroxamic acid and Ru-N-methylbenzohydroxamic systems) in aqueous solution was investigated. We previously proposed that nitrosyl abstraction from hydroxamic acids by Ru(III) involves initial formation of Ru(III)-hydroxamates. Yet, until now, no data on the rate of nitric oxide (NO) release from hydroxamic acids has been published. We now describe a UV-VIS spectroscopic study, where we monitored the decrease in the ligand-to-metal charge-transfer band of a series of Ru(III)-monohydroxamates with time, with a view to gaining an insight into the NO-releasing properties of hydroxamic acids. PMID:18399240

  8. Effects of the Ca2+ chelators EGTA and EDTA on ethanol- or stress-induced gastric mucosal lesions and gastric secretion.

    PubMed

    Glavin, G B; Szabo, S

    1993-03-23

    Ca2+ modulates gastric function and dysfunction as well as the release of cysteine proteases and metalloproteinases which have been implicated in the pathogenesis of gastric mucosal lesions. We thus tested the hypothesis that pretreatment with the Ca2+ chelators, ethylene diamine tetraacetic acid (EDTA) and ethylene glycol-bis(beta-aminoethyl ether)-N,N,N',N'-tetraacetic acid (EGTA) might reduce the experimental gastric mucosal damage induced by restraint cold stress or 1.0 ml of 75% ethanol. Other rats were prepared with chronic indwelling gastric cannulas and the effects of EDTA and EGTA on conscious basal gastric acid output were assessed. In addition, rats were pretreated with EGTA or EDTA prior to pylorus ligation and their effects on acid and pepsin output assessed. Both EDTA and EGTA reduced significantly the extent of ethanol-induced gastric mucosal damage as well as the degree of stress-induced gastric lesions. To further characterize the mechanism of Ca2+ chelator protection against ethanol-induced gastric lesions, some rats were vagotomized or adrenalectomized prior to treatment with EGTA or EDTA, followed by ethanol or stress. Both adrenalectomy and vagotomy abolished gastroprotection by EGTA and slightly reduced that induced by EDTA in both models of experimental gastric mucosal injury. Both EDTA and EGTA reduced significantly basal gastric acid output, an effect which persisted for at least 2 h following their administration. Both compounds also decreased significantly acid and pepsin output in pylorus-ligated rats. We conclude that Ca2+ chelators attenuate both acid-dependent and acid-independent gastric lesions.(ABSTRACT TRUNCATED AT 250 WORDS) PMID:8467872

  9. 78 FR 46265 - Complex Polymeric Polyhydroxy Acids; Exemption From the Requirement of a Tolerance

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-07-31

    ...This regulation establishes an exemption from the requirement of a tolerance for residues of Complex Polymeric Polyhydroxy Acids in or on all food commodities. This regulation eliminates the need to establish a maximum permissible level for residues of Complex Polymeric Polyhydroxy Acids (CPPA) under...

  10. 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

  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. NO removal in continuous BioDeNOx reactors: Fe(II)EDTA2- regeneration, biomass growth, and EDTA degradation.

    PubMed

    van der Maas, Peter; van den Brink, Paula; Utomo, Sudarno; Klapwijk, Bram; Lens, Piet

    2006-06-20

    BioDeNOx is a novel technique for NOx removal from industrial flue gases. In principle, BioDeNOx is based on NO absorption into an aqueous Fe(II)EDTA2- solution combined with biological regeneration of that scrubber liquor in a bioreactor. The technical and economical feasibility of the BioDeNOx concept is strongly determined by high rate biological regeneration of the aqueous Fe(II)EDTA2- scrubber liquor and by EDTA degradation. This investigation deals with the Fe(II)EDTA2- regeneration capacity and EDTA degradation in a lab-scale BioDeNOx reactor (10-20 mM Fe(II)EDTA2-, pH 7.2 +/- 0.2, 55 degrees C), treating an artificial flue gas (1.5 m3/h) containing 60-155 ppm NO and 3.5-3.9% O2. The results obtained show a contradiction between the optimal redox state of the aqueous FeEDTA solution for NO absorption and the biological regeneration. A low redox potential (below -150 mV vs. Ag/AgCl) is needed to obtain a maximal NO removal efficiency from the gas phase via Fe(II)EDTA2- absorption. Fe(III)EDTA- reduction was found to be too slow to keep all FeEDTA in the reduced state. Stimulation of Fe(III)EDTA- reduction via periodical sulfide additions (2 mM spikes twice a week for the conditions applied in this study) was found to be necessary to regenerate the Fe(II)EDTA2- scrubber liquor and to achieve stable operation at redox potentials below -150 mV (pH 7.2 +/- 0.2). However, redox potentials of below -200 mV should be avoided since sulfide accumulation is unwanted because it is toxic for NO reduction. Very low values for biomass growth rate and yield, respectively, 0.043/d and 0.009 mg protein per mg ethanol, were observed. This might be due to substrate limitations, that is the electron acceptors NO and presumably polysulfide, or to physiological stress conditions induced by the EDTA rich medium or by radicals formed in the scrubber upon the oxidation of Fe(II)EDTA2- by oxygen present in the flue gas. Radicals possibly also induce EDTA degradation, which occurs at a

  13. Immunogenicity of a purified and carrier-complexed streptococcal lipoteichoic acid.

    PubMed Central

    Fiedel, B A; Jackson, R W

    1976-01-01

    Solublie teichoic acid could not stimulate the formation of antibodies either as an aqueous solution or in an emulsion with Freund incomplete adjuvant. However, when given as precipitates with methylated bovine serum albumin, it stimulated strong anti-teichoic acid responses. High levels of anti-teichoic acid antibodies usually resulted in allergic symptoms upon secondary challenge either with immunogenic teichoic acid-methylated bovine albumin complexes or with non-immunogenic soluble teichoic acid. These symptoms suggested anaphylatic shock, but probably also included the formation of complement-consuming immune complexes. PMID:786876

  14. Action of Natural Abscisic Acid Precursors and Catabolites on Abscisic Acid Receptor Complexes1[W

    PubMed Central

    Kepka, Michal; Benson, Chantel L.; Gonugunta, Vijay K.; Nelson, Ken M.; Christmann, Alexander; Grill, Erwin; Abrams, Suzanne R.

    2011-01-01

    The phytohormone abscisic acid (ABA) regulates stress responses and controls numerous aspects of plant growth and development. Biosynthetic precursors and catabolites of ABA have been shown to trigger ABA responses in physiological assays, but it is not clear whether these are intrinsically active or whether they are converted into ABA in planta. In this study, we analyzed the effect of ABA precursors, conjugates, and catabolites on hormone signaling in Arabidopsis (Arabidopsis thaliana). The compounds were also tested in vitro for their ability to regulate the phosphatase moiety of ABA receptor complexes consisting of the protein phosphatase 2C ABI2 and the coreceptors RCAR1/PYL9, RCAR3/PYL8, and RCAR11/PYR1. Using mutants defective in ABA biosynthesis, we show that the physiological activity associated with ABA precursors derives predominantly from their bioconversion to ABA. The ABA glucose ester conjugate, which is the most widespread storage form of ABA, showed weak ABA-like activity in germination assays and in triggering ABA signaling in protoplasts. The ABA conjugate and precursors showed negligible activity as a regulatory ligand of the ABI2/RCAR receptor complexes. The majority of ABA catabolites were inactive in our assays. To analyze the chemically unstable 8′- and 9′-hydroxylated ABA catabolites, we used stable tetralone derivatives of these compounds, which did trigger selective ABA responses. ABA synthetic analogs exhibited differential activity as regulatory ligands of different ABA receptor complexes in vitro. The data show that ABA precursors, catabolites, and conjugates have limited intrinsic bioactivity and that both natural and synthetic ABA-related compounds can be used to probe the structural requirements of ABA ligand-receptor interactions. PMID:21976481

  15. Matrix Isolation IR Spectroscopy of 1:1 Complexes of Acetic Acid and Trihaloacetic Acids with Water and Benzene

    NASA Astrophysics Data System (ADS)

    Banerjee, Pujarini; Chakraborty, Tapas

    2015-06-01

    A comparative study of infrared spectral effects for 1:1 complex formation of acetic acid (AA), trifluoroacetic acid (TFAA) and trichloroacetic acid (TFAA) with water and benzene has been carried out under a matrix isolation environment. Despite the large difference in aqueous phase acidities of the three acids, the measured νb{OH}stretching frequencies of the monomers of the three molecules are found to be almost same, and in agreement with gas phase electronic structure calculations. Intrinsic acidities are expressed only in the presence of the proton acceptors, water or benzene. Although electronic structure calculations predict distinct νb{OH} red-shifts for all three acids, the measured spectral features for TCAA and TFAA in this range do not allow unambiguous assignments for the 1:1 complex. On the other hand, the spectral changes in the νb{C=O} region are more systematic, and the observed changes are consistent with predictions of theory. Components of overall binding energy of each complex have been obtained from energy decomposition analysis, which allows determination of the relative contributions of various physical forces towards overall stability of the complexes, and the details will be discussed in the talk.

  16. 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

  17. Recovery of intravenously infused chromium EDTA and lithium sulphate in the urine of cattle and their use as markers to measure urine volume.

    PubMed

    Bowen, M K; Poppi, D P; McLennan, S R

    2009-04-01

    A series of metabolism experiments investigated the recovery of continuous-, intravenously infused chromium complexed with ethylenediamine tetra-acetic acid (CrEDTA) and lithium sulphate in the urine of cattle with a view to using the markers to estimate urine and metabolite output in grazing cattle. The recovery of Cr in urine from these infusions was similar (90%) in metabolism trials when cattle consumed three very contrasting diets: high-grain formulated pellet, lucerne hay (Medicago sativa) or low-quality native grass hay (predominantly Heteropogon contortus). By contrast, Li recovery in urine averaged 46.3 ± 0.40% and 72.6 ± 0.43% for native pasture and lucerne hays, respectively, but was not constant across days. There was negligible transfer of Cr from CrEDTA in blood serum to the rumen or faeces, whereas appreciable quantities of infused Li were found in both. The ratio of urine volume estimated by spot samples and marker dilution of Cr, to urine volume measured gravimetrically, was 1.05. In grazing studies using rumen-fistulated (RF) steers grazing seven different tropical and temperate grass and legume pastures, the ratio of concentrations of purine derivatives (PD) to Cr in spot samples of urine was shown to vary diurnally in the range of 49% to 157% of the average 24 h value. This finding indicated the need for regular sampling of urine to achieve an accurate average value for the PD : Cr ratio in urine for use in estimating urinary PD excretion and hence microbial protein production in the rumen. It was concluded that continuous, intravenous infusion of CrEDTA resulted in a constant recovery of Cr in the urine of cattle across diets and, provided an intensive sampling regime was followed to account for diurnal variation, it would be suitable as a marker to estimate urine volume and urinary output of PD in grazing cattle. PMID:22444379

  18. Structure of microbial communities performing the simultaneous reduction of Fe(II)EDTA.NO2- and Fe(III)EDTA -.

    PubMed

    Kumaraswamy, Rajkumari; Kuenen, J Gijs; Kleerebezem, Robbert; van Loosdrecht, Mark C M; Muyzer, Gerard

    2006-12-01

    BioDeNOx is a combined physicochemical and biological process for the removal of nitrogen oxides (NOx) from flue gas. In the present study, two anaerobic bioreactors performing BioDeNOx were run consecutively (RUN-1 and RUN-2) at a dilution rate of 0.01 h(-1) with Fe(II)EDTA.NO(2-) and Fe(III)EDTA(-) as electron acceptors and ethanol as electron donor. The measured protein concentration of the reactor biomass of both runs was 120 mg/l. Different molecular methods were used to determine the identity and abundance of the bacterial populations in both bioreactors. Bacillus azotoformans strain KT-1 was recognized as a key player in Fe(II)EDTA.NO(2-) reduction. PCR-denaturing gradient gel electrophoresis analysis of the reactor biomass showed a greater diversity in RUN-2 than in RUN-1. Enrichments of Fe(II)EDTA.NO(2-) and Fe(III)EDTA(-) reducers and activity assays were conducted using the biomass from RUN-2 as an inoculum. The results on substrate turnover, overall microbial diversity, and enrichments and finally activity assays confirmed that ethanol was used as electron donor for Fe(II)EDTA.NO(2-) reduction. In addition, the Fe(III)EDTA(-) reduction rate of the microbial community proved to be feasible enough to run the bioreactors, ruling out the chemical reduction of Fe(III)EDTA(-) with sulfide as was proposed by other researchers. PMID:16957895

  19. Detection of Burkholderia cepacia DNA from artificially infected EDTA-blood and lung tissue comparing different DNA isolation methods.

    PubMed

    Merk, S; Meyer, H; Greiser-Wilke, I; Sprague, L D; Neubauer, H

    2006-08-01

    Bacterial DNA (Burkholderia cepacia) was prepared from artificially infected equine ethylenediaminetetraacetic acid (EDTA)-blood and lung tissue by using four standard methods (lysis buffer containing proteinase K, phenol/chloroform/isoamylalcohol-extraction, microwave-treatment, heat treatment) and six commercially available kits (Puregene, High Pure PCR Template Preparation Kit, InstaGene, QiaAmp Tissue Kit, DNAzol and Elu-Quik). After a subsequent polymerase chain reaction (PCR), their efficacy and sensitivity were compared. Concerning the detection limits, the simple lysis with a proteinase K-containing buffer led to the best results for EDTA-blood as well as for artificially infected lung tissue. PMID:16907960

  20. 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

  1. 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 %. PMID:24865501

  2. 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.

  3. 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.

  4. 21 CFR 172.315 - Nicotinamide-ascorbic acid complex.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... (CONTINUED) FOOD FOR HUMAN CONSUMPTION (CONTINUED) FOOD ADDITIVES PERMITTED FOR DIRECT ADDITION TO FOOD FOR...: (a) The additive is the product of the controlled reaction between ascorbic acid and...

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

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... (CONTINUED) FOOD ADDITIVES PERMITTED FOR DIRECT ADDITION TO FOOD FOR HUMAN CONSUMPTION Special Dietary and... the controlled reaction between ascorbic acid and nicotinamide, melting in the range 141 °C to 145...

  6. 21 CFR 172.315 - Nicotinamide-ascorbic acid complex.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... (CONTINUED) FOOD FOR HUMAN CONSUMPTION (CONTINUED) FOOD ADDITIVES PERMITTED FOR DIRECT ADDITION TO FOOD FOR...: (a) The additive is the product of the controlled reaction between ascorbic acid and...

  7. 21 CFR 172.315 - Nicotinamide-ascorbic acid complex.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... (CONTINUED) FOOD FOR HUMAN CONSUMPTION (CONTINUED) FOOD ADDITIVES PERMITTED FOR DIRECT ADDITION TO FOOD FOR...: (a) The additive is the product of the controlled reaction between ascorbic acid and...

  8. 21 CFR 172.315 - Nicotinamide-ascorbic acid complex.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... (CONTINUED) FOOD FOR HUMAN CONSUMPTION (CONTINUED) FOOD ADDITIVES PERMITTED FOR DIRECT ADDITION TO FOOD FOR...: (a) The additive is the product of the controlled reaction between ascorbic acid and...

  9. 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

  10. 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

  11. 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.

  12. 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…

  13. 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. PMID:25055748

  14. 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.

  15. 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.

  16. Stability constants of europium complexes with a nitrogen heterocycle substituted methane-1,1-diphosphonic acid

    SciTech Connect

    Jensen, M.P.; Rickert, P.G.; Schmidt, M.A.; Nash, K.L.

    1996-06-01

    Even in moderately acidic solutions ([H{sup +}] > 0.01 M), N-piperidinomethane-1,1-diphosphonic acid (H{sub 4}PMDPA) is a strong complexant of trivalent lanthanide ions that shows enhanced complex solubility over previously studied 1,1-diphosphonic acids. The protonation constants of PMDPA in 2.0 M H/NaClO{sub 4} were determined by potentiometric and NMR titrations, and the stability constants for formation of complexes with Eu{sup 3+} were determined by solvent extraction. Difference in protonation equilibria induced by addition of the nitrogen heterocycle results in an increase in the complexation strength of PMDPA. In solutions containing 0.1 M H{sup +} and ligand concentrations greater than 0.02 M, PMDPA is the most effective 1,1-diphosphonic acid for europium complexation studied thus far.

  17. Spectral and thermal study of the ternary complexes of nickel with sulfasalazine and some amino acids

    NASA Astrophysics Data System (ADS)

    Soliman, Ahmed A.

    2006-12-01

    The ternary complexes of Ni(II) with sulfasalazine (H 3SS) as a primary ligand and alanine (ala), aspartic acid (asp), histidene (hist), methionine (meth) and serine (ser) amino acids as secondary ligands have been synthesized. Characterization of the complexes was based on elemental analyses, IR, UV-vis, mass spectra, magnetic moment and thermal analysis (TG). The isolated complexes were found to have the general formula [M(HSS)(AA)]4H 2O (AA = ala, asp, hist, meth, or ser amino acid) where nickel is tetra-coordinated. The thermal stability of the complexes was studied and the weight losses for the decomposition of the complexes were calculated and correlated with the mass fragmentation pattern. In most cases, the amino acid moiety is removed along with the Schiff base moiety leaving NiO as a metallic residue. The metallic residue was confirmed by powder XRD measurements.

  18. Poly(anhydride-esters) comprised exclusively of naturally occurring antimicrobials and EDTA: antioxidant and antibacterial activities.

    PubMed

    Carbone-Howell, Ashley L; Stebbins, Nicholas D; Uhrich, Kathryn E

    2014-05-12

    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

  19. EDTA-dependent pseudothrombocytopenia complicated by eosinophilic pneumonia.

    PubMed

    Ohashi, Naoko; Nakamura, Kensuke; Inokuchi, Ryota; Sato, Hajime; Tokunaga, Kurato; Fukuda, Tatsuma; Nakajima, Susumu; Yahagi, Naoki

    2013-07-01

    EDTA-dependent pseudothrombocytopenia (EDTA-PTCP) is a phenomenon that occurs in vitro when EDTA reacts with harvested blood. EDTA-dependent pseudothrombocytopenia usually does not indicate thrombocytopenia in vivo. Here, we report the first case of EDTA-PTCP complicated by eosinophilic pneumonia. A 70-year-old man with rectal cancer was admitted to the hospital for a liver abscess and rectal cancer. At the time of admission, his platelet count was 20,000/μL, but a peripheral blood smear showed platelet aggregation and the platelet count for a kanamycin-added EDTA blood sample was 180,000/μL. The patient's respiratory status worsened after treatment for the liver abscess and rectal cancer. The patient's bronchoalveolar lavage contained 45% eosinophils, and a diagnosis of acute eosinophilic pneumonia was made. In recent studies, the occurrence of eosinophilic disease has been shown in idiopathic thrombocytopenic purpura. EDTA-dependent pseudothrombocytopenia is an in vitro phenomenon, although platelet activation that results in eosinophil invasion may occur in severe cases. PMID:23702069

  20. 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

  1. 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 Central

    Wreesmann, Carel Theo Jozef

    2014-01-01

    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. PMID:24521261

  2. Trifluoroacetic acid as excipient destabilizes melittin causing the selective aggregation of melittin within the centrin-melittin-trifluoroacetic acid complex.

    PubMed

    Pastrana-Rios, Belinda; Del Valle Sosa, Liliana; Santiago, Jorge

    2015-07-01

    Trifluoroacetic acid (TFA) may be the cause of the bottleneck in high resolution structure determination for protein-peptide complexes. Fragment based drug design often involves the use of synthetic peptides which contain TFA (excipient). Our goal was to explore the effects of this excipient on a model complex: centrin-melittin-TFA. We performed Fourier transform infrared, two-dimensional infrared correlation spectroscopies and spectral simulations to analyze the amide I'/I'* band for the components and the ternary complex. Melittin (MLT) was observed to have increased helicity upon its interaction with centrin, followed by the thermally induced aggregation of MLT within the ternary complex in the TFA presence. PMID:26798810

  3. Influence of fulvic acid on bacteriophage adsorption and complexation in soil.

    PubMed Central

    Bixby, R L; O'Brien, D J

    1979-01-01

    The effect of fulvic acid, the major fraction of natural soluble organic matter, on the adsorption of MS2 bacteriophage to soil was investigated in controlled laboratory experiments. Batch experiments together with scanning electron microscopy-energy-dispersive X-ray analysis showed that fulvic acid complexed phage, which prevented its adsorption to soil. Phage strongly adsorbed to soil in the absence of fulvic acid. Phage which was complexed with fulvic acid was not irreversibly inactivated and could become viable under proper conditions, illustrating the importance of assay and elution procedures in the recovery of virus from aqueous solutions. PMID:396884

  4. 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.

  5. Metal ion adsorption to complexes of humic acid and metal oxides: Deviations from the additivity rule

    SciTech Connect

    Vermeer, A.W.P.; McCulloch, J.K.; Van Riemsdijk, W.H.; Koopal, L.K.

    1999-11-01

    The adsorption of cadmium ions to a mixture of Aldrich humic acid and hematite is investigated. The actual adsorption to the humic acid-hematite complex is compared with the sum of the cadmium ion adsorptivities to each of the isolated components. It is shown that the sum of the cadmium ion adsorptivities is not equal to the adsorption to the complex. In general, the adsorption of a specific metal ion to the complex can be understood and qualitatively predicted using the adsorptivities to each of the pure components and taking into account the effect of the pH on the interaction between humic acid and iron oxide on the metal ion adsorption. Due to the interaction between the negatively charged humic acid and the positively charged iron oxide, the adsorption of metal ions on the mineral oxide in the complex will increase as compared to that on the isolated oxide, whereas the adsorption to the humic acid will decrease as compared to that on the isolated humic acid. As a result, the overall adsorption of a specific metal ion to the complex will be smaller than predicted by the additivity rule when this metal ion has a more pronounced affinity for the humic acid than for the mineral oxide, whereas it will be larger than predicted by the additivity rule when the metal ion has a higher affinity for the oxide than for the humic acid.

  6. The complex amino acid diet of Francisella in infected macrophages

    PubMed Central

    Barel, Monique; Ramond, Elodie; Gesbert, Gael; Charbit, Alain

    2015-01-01

    Francisella tularensis, the agent of the zoonotic disease tularemia, is a highly infectious bacterium for a large number of animal species and can be transmitted to humans by various means. The bacterium is able to infect a variety of cell types but replicates in mammalian hosts mainly in the cytosol of infected macrophages. In order to resist the stressful and nutrient-restricted intracellular environments, it encounters during its systemic dissemination, Francisella has developed dedicated stress resistance mechanisms and adapted its metabolic and nutritional needs. Recent data form our laboratory and from several other groups have shown that Francisella simultaneously relies on multiple host amino acid sources during its intracellular life cycle. This review will summarize how intracellular Francisella use different amino acid sources, and their role in phagosomal escape and/or cytosolic multiplication and systemic dissemination. We will first summarize the data that we have obtained on two amino acid transporters involved in Francisella phagosomal escape and cytosolic multiplication i.e., the glutamate transporter GadC and the asparagine transporter AnsP, respectively. The specific contribution of glutamate and asparagine to the physiology of the bacterium will be evoked. Then, we will discuss how Francisella has adapted to obtain and utilize host amino acid resources, and notably the contribution of host transporters and autophagy process in the establishment of a nutrient-replete intracellular niche. PMID:25705612

  7. 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. PMID:26242286

  8. 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

  9. Evaluation of structural and functional properties of chitosan-chlorogenic acid complexes.

    PubMed

    Wei, Zihao; Gao, Yanxiang

    2016-05-01

    The objectives of the present study were to first synthesize chitosan-chlorogenic acid (CA) covalent complex and then compare structural and functional properties between chitosan-CA covalent complex and physical complex. First, chitosan-CA covalent complex was synthesized and its total phenolic content was as high as 276.5 ± 6.2 mg/g. Then structural and functional properties of chitosan-CA covalent and physical complexes were analyzed. The covalent reaction induced formation of both amide and ester bonds in chitosan. Data of X-ray diffraction (XRD) and scanning electron microscopy (SEM) indicated that the complexations of CA changed crystallinity and morphology of chitosan, and covalent complexation induced a larger change of physical structure than physical complexation. In terms of functional properties, chitosan-CA covalent complex exhibited better thermal stability than physical complex in terms of antioxidant activity, and the viscosity of chitosan was significantly increased by covalent modification. PMID:26820353

  10. 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

  11. 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

  12. Functionalization of PAMAM dendrimers with [Ru(III)(edta)(H2O)](-).

    PubMed

    Benini, P G Z; McGarvey, B R; Franco, D W

    2008-11-01

    The anchoring of K[Ru(III)(edta)(Cl)] on poly(amidoamine) dendrimers (PAMAM of three generations G(x)/Ru (x=0, 2 and 3)) through a peptide type bond yielded the aquo species, [Ru(III)(edta)(H2O)] on dendrimer surface, and upon NO exposure, yielded their nitrosyl analogues, G(x)/RuNO. Characterization of these compounds by elemental analysis, and a UV-vis, IR and 13C NMR spectroscopies indicated the immobilization of 4, 12 and 29 molecules of [Ru(III)(edta)(H2O)] or of the nitrosyl complex [Ru(II)(edta)NO] on the dendrimer surface for G(X)=0, 2 and 3, respectively. For each complex the electrochemical spectrum presented only one redox process with redox potential values of -0.20 and -0.32 V(vs SCE) attributed to the Ru(III)/Ru(II) and NO+/NO(0) couples in G(x)/Ru and G(x)/RuNO, respectively. The one-electron reduction of G(x)/RuNO+ generates G(x)/RuNO(0), which undergoes aquation with a k(-NO) of 2.1+/-0.7 x 10(-3)s(-1) (pH 1.0, mu=0.2 mol/L, CF3COOH/NaCF3COO, 25 degrees C). The G(x)/RuNO species induced a relaxing effect in aortic rings denuded of endothelium and exhibited in vitro assay trypanocidal activity. PMID:18503781

  13. Metal ion complexation properties of fulvic acids extracted from composted sewage sludge as compared to a soil fulvic acid.

    PubMed

    Esteves da Silva, Joaquim C G; Oliveira, César J S

    2002-07-01

    Complexation properties of an anthropogenic fulvic acid (FA) extracted from a composted sewage sludge (csFA) for Cu(II), Pb(II) and Cd(II) were studied at pH=6 and at a concentration of 25 mg L(-1). For the case of Cu(II), a particular analysis of the complexation phenomena was done at pH values of 3, 4, 5 and 6 and at aqueous FA concentrations of 25, 50 and 100 mg L(-1) by synchronous excitation molecular fluorescence spectroscopy (SyF). Potentiometric titrimetry with Cu(II), Pb(II), Cd(II) and H+ ion-selective electrodes and acid-base conductimetric titrations were used to obtain experimental information about the acid properties and complexation phenomena. A comparison of the results obtained for csFA with a natural soil FA (sFA) was made. Differences have been detected in the structural composition of the two samples and in the structure of the binding sites. In the csFA, binding site structures containing nitrogen probably play an important role in the complexation, besides oxygen containing structures. Complexation by sFA is mainly due to carboxylic and phenolic structures. Nevertheless, this work shows that csFA have macroscopic complexation properties (magnitude of the conditional stability constant and binding sites concentration) somewhat similar to the natural sFA samples. PMID:12188141

  14. 21 CFR 73.2120 - Disodium EDTA-copper.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... COLOR ADDITIVES EXEMPT FROM CERTIFICATION Cosmetics § 73.2120 Disodium EDTA-copper. (a) Identity. The... amounts consistent with good manufacturing practices in the coloring of shampoos which are cosmetics....

  15. 21 CFR 73.2120 - Disodium EDTA-copper.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... COLOR ADDITIVES EXEMPT FROM CERTIFICATION Cosmetics § 73.2120 Disodium EDTA-copper. (a) Identity. The... amounts consistent with good manufacturing practices in the coloring of shampoos which are cosmetics....

  16. 21 CFR 73.2120 - Disodium EDTA-copper.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... COLOR ADDITIVES EXEMPT FROM CERTIFICATION Cosmetics § 73.2120 Disodium EDTA-copper. (a) Identity. The... amounts consistent with good manufacturing practices in the coloring of shampoos which are cosmetics....

  17. 21 CFR 73.2120 - Disodium EDTA-copper.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... COLOR ADDITIVES EXEMPT FROM CERTIFICATION Cosmetics § 73.2120 Disodium EDTA-copper. (a) Identity. The... amounts consistent with good manufacturing practices in the coloring of shampoos which are cosmetics....

  18. 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

  19. [Study of the circular dichroism for tribasic complex of amine derivative of beta-cyclodextrindien-Cu2+ -benzoic acid].

    PubMed

    Hu, J; Zhang, H; Shen, B

    1998-02-01

    The circular dichroism spectra of beta-cyclodextrindien, beta-cyclodextrindien-Cu2+ complex, beta-cyclodextrindien-benzoic acid complex, tribasic complex of beta-cyclodextrindien-Cu2+ -benzoic acid were determined by using JASCO J-20C automatic recording spectropolarimeter. The attribution of the bands obtained were made according to the order of orbit energy of Cu2+ complex and benzoic acid, and the coordination structure of tribasic complex of amine derivative of beta-cyclodextrindien-Cu2+ -benzoic acid were decided acording to the structure character of Cu2+ complex and KAJART sector rule of inclusion complex of beta-cyclodextrindien with aromatic compounds. PMID:15810322

  20. EDTA-dependent pseudothrombocytopenia in a case of liver cirrhosis.

    PubMed

    Matarazzo, M; Conturso, V; Di Martino, M; Chiurazzi, F; Guida, G; Morante, R

    2000-06-01

    Pseudothrombocytopenia (PTCP) is the consequence of an EDTA-activated platelet agglutination, resulting in a spuriously low platelet count. We report the case of a 54-year-old man with EDTA-dependent PTCP associated with liver cirrhosis. He couldn't undergo endoscopic examination and dental care for two years because of a previous diagnosis of severe thrombocytopenia secondary to liver cirrhosis. Lack of PTCP recognition may lead the physician to misdiagnosis and mismanagement of the patient. PMID:10965778

  1. 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. PMID:10830846

  2. [Experimental analysis and countermeasures for EDTA-dependent Pseudothrombocytopenia].

    PubMed

    Mao, Wei-Yu; Huo, Mei; Ye, Su-Dan; Gong, Wen-Bo

    2014-10-01

    The purpose of this study was to investigate the incidence of clinically common EDTA-dependent pseudo-thrombocytopenia (EDTA-PTCP) and methols for treating this diseese. A total of 1326 cases of thrombocytopenia found at blood routine examination were amalyzed anong 71 535 patients hospitalized in our hospital from January 2010 to May 2013, and 87 cases of PTCP caused EDTA-K anticoagulant were analyzed again by using sodium citrate auticoagulant, at the same time the platelet formation distribution was observed by microscopy of smear with Wright-Giemsa staining. The results showed that the platelet count detected by using EDTA-K anticoagulant in 87 cases was (56 ± 27)×10(9)/L, while the platelet count detected by using sodium citrate was (185 ± 39)×10(9)/L (t = 1.83,P < 0.01). The pseudo-thrombocytopenia incidence cansed by EDTA-K was 0.12%, it was 6.56% for the total number of thrombocytopenia. It is concluded that the incidence of PTCP cansed by EDTA-K is 0.12%, the PTCP is easily misdiagnosed. Therefore, the specimens of platelet count <100 10(9)/L should be tested again. When the platelet aggregation is found, the specimens should be examined again by using sodium citrate in order to avoid misdiagnosis. PMID:25338586

  3. 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.

  4. Analysis of Complexation Equilibria of Polyacrylic Acid by a Donnan-Based Concept

    PubMed

    Miyajima; Mori; Ishiguro

    1997-03-01

    Complexation equilibria of uni- and divalent metal ions (Ag+, Ca2+, Cu2+, and Pb2+) with polyacrylic acid (PAA) have been studied at various degrees of dissociation (alpha) of PAA under different sodium salt concentration levels at 25°C. Both pH and pM(MZ+ = Ag+, Ca2+, Cu2+, and Pb2+) of equilibrium mixture solutions of MZ+/PAA/Na+ (excess) have been determined concurrently by a potentiometric titration method. The electrostatic effect inherent in the polyion-metal ion binding equilibria has been evaluated by a Donnan-based concept and is corrected for by the use of a nonideality term of acid dissociation equilibria of the polyacid as a probe. For Ag+-PAA and Ca2+-PAA bindings, only monodentate ligand complexes, (MA)(Z-1), have proven to be formed, whereas for Cu2+ and Pb2+ ion bindings, formation of both monodentate and bidentate ligand complexes have been observed. For both Cu2+-PAA and Pb2+-PAA systems, bidentate carboxylate complex formation is predominant at alpha > ca. 0.3, whereas at alpha < ca. 0.3, formation of monodentate carboxylate complexes becomes appreciable as alpha decreases. Stability constants of these complexes together with the intra-molecular complexation equilibrium constants expressed by the ratio of the concentrations of bidentate complexes to monodentate complexes have successfully been evaluated and are compared with each other in order to discuss the multidentate complexation properties of the polycarboxylic acid. PMID:9245334

  5. Fluorosed fibroblast attachment on fluorosed and nonfluorosed teeth after SRP and EDTA root biomodification

    PubMed Central

    Girotra, Neha; Vandana, K. L.

    2014-01-01

    Background: Fluorosis causes mineralization changes in the tooth and can lead to morphologic alterations of fibroblasts. To understand the effect of fluorosis on periodontal healing, the initial step during healing, such as fibroblast attachment to the root surface, needs to be evaluated. Hence, the objective of the present study was to study the attachment of fluorosed fibroblasts on the fluorosed and nonfluorosed root fragments. Materials and Methods: A total of 56 fluorosed and nonfluorosed, periodontally healthy and diseased tooth roots were obtained and allotted to eight groups: Fluorosed and nonfluorosed healthy controls (FH and NFH, respectively), fluorosed and nonfluorosed diseased controls (FD and NFD, respectively), fluorosed and nonfluorosed roots treated with scaling and root planing (FD + S and NFD + S, respectively), and similar groups treated with scaling and root planing and 24% ethylenediaminetetraacetic acid (EDTA) gel application for 2 min (FD + SE and NFD + SE, respectively). After the respective treatment, the root fragments were incubated in the human periodontal ligament fibroblast cells obtained and cultured from freshly extracted healthy human fluorosed premolar tooth root. Results: In the nonfluorosed roots category, greater attachment was found in the untreated nonfluorosed diseased (P = 0.036) and SRP-treated nonfluorosed diseased groups (P = 0.008) as compared to the nonfluorosed healthy group. While in the fluorosed roots category, no significant difference was observed in FL-FA (P > 0.05) within the group. However, no attachment was observed in EDTA-treated fluorosed root fragments. When fluorosed groups were compared to nonfluorosed groups, no significant changes were noted between the groups. Conclusion: SRP proves to be a standard requirement for fibroblast attachment to occur both in fluorosed and nonfluorosed roots. Although there was no significant difference in attachment between SRP and SRP + EDTA among fluorosed roots, EDTA

  6. Preparation of solid drug/cyclodextrin complexes of acidic and basic drugs.

    PubMed

    Loftsson, T; Sigurdsson, H H; Másson, M; Schipper, N

    2004-01-01

    One of the main obstacles in pharmaceutical applications of cyclodextrins is their increase of the formulation bulk. Even at maximum incorporation 500 mg of a solid drug/cyclodextrin complex will only contain between 50 and 125 mg of the drug, assuming a low molecular weight drug (MW 200 to 400 Dalton) and an average molecular weight cyclodextrin (MW about 1500 Dalton). In general, the complexation efficiency is low and consequently the complex powder contains a significant amount of empty cyclodextrin molecules. In the present study the complexation efficiency is increased by ionization of the drug molecule through addition of volatile acid (i.e. acetic acid) or base (i.e. ammonia) to the aqueous complexation media of basic or acidic drugs, respectively. The volatile acid or base was then removed during lyophilization and heating in a vacuum oven resulting in formation of solid cyclodextrin complexes of the unionized drug. Thus, the complexation efficiency was temporary increased by the ionization but then again decreased leading to formation of the thermodynamically unstable solid drug/cyclodextrin complexes. When dissolved the energy of the system was lowered by expelling the drug molecules from the cyclodextrin cavities resulting in formation of supersaturated drug solutions and ultimately precipitation of the drug. PMID:14964417

  7. Luminescent and triboluminescent properties of europium(III) complex with cinnamic acid

    NASA Astrophysics Data System (ADS)

    Kalinovskaya, I. V.; Mirochnik, A. G.; Nagornyi, I. G.

    2014-10-01

    An intensely emitting crystalline europium(III) complex with cinnamic acid [Eu(Cin)3] n and exhibiting triboluminescent properties is synthesized. It is established that the measured photo- and triboluminescence spectra are identical for the above polymeric non-centrosymmetric complex and are determined by the characteristic f-f luminescence of the europium(III) ion.

  8. Thermodynamics of lanthanide and uranyl complexes with tetrahydrofuran-2,3,4,5-tetracarboxylic acid (THFTCA).

    SciTech Connect

    Morss, L. R.; Nash, K. L.; Tennessee Technological Univ.

    2000-01-01

    We present the results of an investigation of the thermochemistry of the complexation of La{sup 3+} Nd{sup 3+}, Eu{sup 3+}, Dy{sup 3+}, Tm{sup 3+}, and UO{sub 2}{sup 2+} by tetrahydrofuran-2,3,4,5-tetracarboxylic acid (THFTCA). This predisposed structural analog to oxydiacetic acid (ODA) has been previously shown both to exhibit greater sensitivity to lanthanide cation radius than complexes with the unconstrained ODA and to form anomalously weak complexes with UO{sub 2}{sup 2+}. Our purpose is to interpret these observations in terms of the balance between enthalpy and entropy contributions to the overall complexation thermodynamics. Enthalpies have been calculated from titration calorimetry experiments both for the protonation of the free ligand and for the formation of selected 1:1 and 1:2 complexes in pH 2-3 acidic media (I = 0.1 M). The complexation entropies for the lanthanide complexes have been calculated using the previously reported stability constants for the MH{sub 2}L{sup +}, MHL, and M(H{sub 2}L){sup 2-}. The stability constants for the uranyl complexes have been determined by potentiometric titration and these values used to calculate the thermodynamic parameters. Complexation enthalpies for the 1:1 lanthanide-THFTCA complexes (MH{sub 2}L{sup +} species) are nearly identical to those of the lanthanide ODA complexes. Therefore, the size-selectivity observed in the lanthanide-THFTCA complexes arises from the complexation entropy. The comparative weakness of the uranyl complexes with THFTCA also is accounted for thermodynamically in the entropy term. Calculations based on an electrostatic model for complexation entropy and molecular mechanics modeling are used to help interpret the experimental results.

  9. 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

  10. 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.

  11. [Preparation and spectra of the complexes of the first series transition metals with diphenic acid].

    PubMed

    Wu, Ai-zhi; Wang, Jian-jun; Ren, Yan-wei; Chen, Jing; Li, Jun; Zhang, Feng-xing

    2004-04-01

    The ligand diphenic acid has been synthesized and the corresponding complexes of transition metal Co, Ni and Mn with diphenic acid have been prepared and characterized by the elementary analysis, IR spectra and ultraviolet-visible spectra. The results of IR show that the vas and vs of -CO2- in the complexes are lower than those of ligand diphenic acid, which can be explained by the coordinating between metal and ligand. In addition, compared with the complex IR spectra, the IR spectra of ligand became complicated due to the ligand polymerization through hydrogen bond. The UV-Vis spectra show that the ligand has three absorption peaks at 288, 273 and 270 nm, respectively, and these are slightly shifted in the complexes. Because the metal d-d absorption is weak, only in Co(C14H8O4) x 2H2O there is a d-d absorption at 537 nm. PMID:15766146

  12. 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.

  13. 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.

  14. Synthesis, spectral studies and biological evaluation of 2-aminonicotinic acid metal complexes.

    PubMed

    Nawaz, Muhammad; Abbasi, Muhammad Waseem; Hisaindee, Soleiman; Zaki, Muhammad Javed; Abbas, Hira Fatima; Mengting, Hu; Ahmed, M Arif

    2016-05-15

    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. PMID:26945123

  15. 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.

  16. EDTA-treated cotton-thread microfluidic device used for one-step whole blood plasma separation and assay.

    PubMed

    Ulum, Mokhamad Fakhrul; Maylina, Leni; Noviana, Deni; Wicaksono, Dedy Hermawan Bagus

    2016-04-21

    This study aims to observe the wicking and separation characteristics of blood plasma in a cotton thread matrix functioning as a microfluidic thread-based analytical device (μTAD). We investigated several cotton thread treatment methods using ethylenediaminetetraacetic acid (EDTA) anticoagulant solution for wicking whole blood samples and separating its plasma. The blood of healthy Indonesian thin tailed sheep was used in this study to understand the properties of horizontal wicking and separation on the EDTA-treated μTAD. The wicking distance and blood cell separation from its plasma was observed for 120 s and documented using a digital phone camera. The results show that untreated cotton-threads stopped the blood wicking process on the μTAD. On the other hand, the deposition of EDTA anticoagulant followed by its drying on the thread at room temperature for 10 s provides the longest blood wicking with gradual blood plasma separation. Furthermore, the best results in terms of the longest wicking and the clearest on-thread separation boundary between blood cells and its plasma were obtained using the μTAD treated with EDTA deposition followed by 60 min drying at refrigerated temperature (2-8 °C). The separation length of blood plasma in the μTADs treated with dried-EDTA at both room and refrigerated temperatures was not statistically different (P > 0.05). This separation occurs through the synergy of three factors, cotton fiber, EDTA anticoagulant and blood platelets, which induce the formation of a fibrin-filter via a partial coagulation process in the EDTA-treated μTAD. An albumin assay was employed to demonstrate the efficiency of this plasma separation method during a one-step assay on the μTAD. Albumin in blood is an important biomarker for kidney and heart disease. The μTAD has a slightly better limit of detection (LOD) than conventional blood analysis, with an LOD of 114 mg L(-1) compared to 133 mg L(-1), respectively. However, the μTAD performed

  17. 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

  18. Accurate ab initio prediction of NMR chemical shifts of nucleic acids and nucleic acids/protein complexes.

    PubMed

    Victora, Andrea; Möller, Heiko M; Exner, Thomas E

    2014-12-16

    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 (r(2)) 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

  19. [Investigation of effect and process of nitric oxide removal in rotating drum biofilter coupled with absorption by Fe(II) (EDTA)].

    PubMed

    Chen, Jun; Yang, Xuan; Yu, Jian-Ming; Jiang, Yi-Feng; Chen, Jian-Meng

    2012-02-01

    In order to accelerate the NO removal efficiency, a novel and effective system was developed for the complete treatment of NO from flue gases. The system features NO absorption by Fe(II) (EDTA) and biological denitrification in a rotating drum biofilter (RDB) so as to promote biological reduction. The experimental results show that a moderate amount of Fe(II) (EDTA) was added to the nutrient solution to improve the mass transfer efficiency of NO from gas to liquid, with the concomitant formation of nitrosyl complex Fe(II) (EDTA)-NO. Under the experimental conditions of rotational speed was at 0.5 r x min(-1), EBRT of 57.7 s, temperature was at 30 degrees C, pH was 7-8, with the increasing concentration of Fe(II) (EDTA) was from 0 mg x L(-1) to 500 mg x L(-1), the NO removal efficiency was improved from 61.1% to 97.6%, and the elimination capacity was from 16.2 g (m3 x h)(-1) to 26.7 g (m3 x h)(-1). In order to simulate the denitrifying process of waste gas containing NO by using RDB coupled with Fe(II) (EDTA) absorption, a tie-in equation of NO removal and the Fe(II) (EDTA) concentration added in RDB was established. The experimental NO removal efficiency change tendency agrees fairly with that predicted by the proposed equation. PMID:22509594

  20. Ternary complexation of carvedilol, beta-cyclodextrin and citric acid for mouth-dissolving tablet formulation.

    PubMed

    Pokharkar, Varsha; Khanna, Abhishek; Venkatpurwar, Vinod; Dhar, Sheetal; Mandpe, Leenata

    2009-06-01

    The purpose of this study was to improve the solubility and dissolution rate of carvedilol by forming a ternary complex with beta-cyclodextrin and citric acid and to formulate its mouth-dissolving tablets. The rationale for preparing mouth-dissolving tablet of carvedilol was to make the drug available in a soluble form in the mouth, which would facilitate its absorption from the buccal cavity. This would help to overcome its first-pass metabolism and thereby improve bioavailability. Phase solubility studies revealed the ability of beta-cyclodextrin and citric acid to complex with carvedilol and significantly increase its solubility. Ternary complexation of carvedilol was carried out with beta-cyclodextrin and citric acid by physical mixing, kneading and spray drying methods and the prepared complexes were characterized by Fourier transform infra red spectroscopy, differential scanning calorimetry, powder X-ray diffractometry, scanning electron microscopy and complexation efficiency. The complex obtained by the spray drying method resulted in highest complexation efficiency and a 110-fold increase in the solubility of carvedilol. The mouth-dissolving tablets formulated using the spray dried complex with suitable excipients showed 100 % dissolution within five minutes. Accelerated stability studies of mouth-dissolving tablets carried out as per ICH guidelines revealed that the tablets were stable. PMID:19564138

  1. 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

  2. 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. PMID:22160716

  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. 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

  5. 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

  6. 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.

  7. Metal associations in soils before and after EDTA extractive decontamination: implications for the effectiveness of further clean-up procedures.

    PubMed

    Barona, A; Aranguiz, I; Elías, A

    2001-01-01

    The distribution of Pb, Ni and Zn in two contaminated soils was determined before and after treating the soils with an EDTA solution. After the EDTA extraction, the proportion of Pb accumulated in the acid-extractable fraction considerably increased, which was related to the greater degree of metal extraction from the other fractions. EDTA was also able to extract certain amounts of Pb, Zn and Ni from the silicate matrix, which implied that these extractable amounts were not so strongly fixed to the residual fraction as previously supposed. As a consequence, after EDTA application, metal content (especially Pb) remained more weakly adsorbed to soil components (more easily leachable), potentially favouring the application of phytoremediation technologies. The extraction recoveries (for only one application) were generally low for the three metals (33-37% for Pb, 5-11% for Ni and 14-19% for Zn), although this fact is an advantage as plants would not be able to assimilate very high mobilised contents of metals. PMID:11351764

  8. 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

  9. Preparation and spectral investigation of inclusion complex of caffeic acid with hydroxypropyl-β-cyclodextrin

    NASA Astrophysics Data System (ADS)

    Zhang, Min; Li, Jinxia; Zhang, Liwei; Chao, Jianbin

    2009-01-01

    The inclusion complexation behavior of caffeic acid (CA) with hydroxypropyl-β-cyclodextrin (HP-β-CD) was studied by UV-vis, fluorescence spectroscopy and nuclear magnetic resonance spectroscopy (NMR). Experimental conditions including the concentration of HP-β-CD and media acidity were investigated in detail. The result suggested HP-β-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-β-CD according to the phase-solubility diagram. The spatial configuration of complex has been proposed based on 1H NMR and two-dimensional (2D) NMR, the result suggested that CA was entrapped inside the hydrophobic core of HP-β-CD with the lipophilic aromatic ring and the portion of ethylene.

  10. 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.

  11. 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.

  12. 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.

  13. 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.

  14. 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.

  15. 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. PMID:25714329

  16. Effect of sulfur compounds on biological reduction of nitric oxide in aqueous Fe(II)EDTA2- solutions.

    PubMed

    Manconi, Isabella; van der Maas, Peter; Lens, Piet N L

    2006-08-01

    Biological reduction of nitric oxide (NO) in aqueous solutions of EDTA chelated Fe(II) is one of the main steps in the BioDeNOx process, a novel bioprocess for the removal of nitrogen oxides (NOx) from polluted gas streams. Since NOx contaminated gases usually also contain sulfurous pollutants, the possible interferences of these sulfur compounds with the BioDeNOx process need to be identified. Therefore, the effect of the sulfur compounds Na2SO4, Na2SO3, and H2S on the biological NO reduction in aqueous solutions of Fe(II)EDTA2- (25 mM, pH 7.2, 55 degrees C) was studied in batch experiments. Sulfate and sulfite were found to not affect the reduction rate of Fe(II)EDTA2- complexed NO under the conditions tested. Sulfide, either dosed externally or formed during the batch incubation out of endogenous sulfur sources or the supplied sulfate or sulfite, influences the production and consumption of the intermediate nitrous oxide (N2O) during Fe(II)EDTA2- bound NO reduction. At low concentrations (0.2 g VSS/l) of denitrifying sludge, 0.2 mM free sulfide completely inhibited the nitrosyl-complex reduction. At higher biomass concentrations (1.3-2.3 g VSS/l), sulfide (from 15 microM to 0.8 mM) induced an incomplete NO denitrification with N2O accumulation. The reduction rates of NO to N2O were enhanced by anaerobic sludge, presumably because it kept FeEDTA in the reduced state. PMID:16517188

  17. Analysis of 15 cases with platelet EDTA-dependent antibodies.

    PubMed

    Zupańska, B; Maślanka, K

    1995-01-01

    In 15 patients with thrombocytopenia EDTA-dependent platelet antibodies (IgM agglutinins active in 20 degrees C) were detected. These antibodies were found in patients with autoimmune diseases, infections and neoplasma as well as in healthy persons (including pregnant woman). In 10 persons pseudothrombocytopenia (PTCP) was diagnosed since the low platelet counts were found only in EDTA-blood, and the patients did not have bleeding symptoms. In 5 other cases EDTA-dependent antibodies were not the only cause of thrombocytopenia since the low platelet counts were also observed in the citrate-blood and occassionally the bleeding symptoms occurred; in 3 of them in addition autoantibodies were suspected. Due to the proper diagnosis of PTCP, in five patients unnecessary corticotherapy was discontinued, one person avoided splenectomy, in two patients previously postponed surgery was performed and one person could be passed for employment. PMID:8571737

  18. Growth and characterisation of EDTA-added TGS crystals

    NASA Astrophysics Data System (ADS)

    Meera, K.; Claude, A.; Muralidharan, R.; Choi, C. K.; Ramasamy, P.

    2005-12-01

    Triglycine sulfate (TGS) crystal with 1 wt% of EDTA (ETGS) addition was grown from aqueous solution by slow-cooling technique. The addition of EDTA enhanced the metastable zone width of TGS solution and, thereby, increased the growth rate of TGS crystal. The powder X-ray diffraction analysis showed a slight change in the cell parameter values of ETGS crystal. The presence of various functional groups in the grown crystal is identified from FTIR analysis. Optical transmission studies on ETGS crystal showed a lower UV cut-off of 237 nm and the transmission percentage of 95%. The dielectric studies were carried out to identify the phase transition temperature and to find the dielectric constant. The pyroelectric co-efficient was calculated, which increased slightly with EDTA addition in TGS. Piezoelectric studies were also done on the grown crystals. Microhardness studies carried out using Leitz-Weitzler hardness tester showed that the ETGS crystal was softer than pure TGS crystal.

  19. IRON DISSOCIATES FROM THE NAFEEDTA COMPLEX PRIOR TO OR DURING INTESTINAL ABSORPTION IN RATS

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Sodium Iron EDTA (NaFeEDTA) has superior iron bioavailability especially in foods containing iron absorption inhibitors. However, mechanisms involved in the absorption and subsequent partitioning of iron complexed with EDTA are poorly understood. Our objectives were to compare retention and tissue...

  20. 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.

  1. Bioreduction of uranium(VI) complexed with citric acid by Clostridia affects its structure and solubility.

    PubMed

    Francis, A J; Dodge, C J

    2008-11-15

    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. PMID:19068806

  2. Mononuclear metal complexes of organic carboxylic acid derivatives: Synthesis, spectroscopic characterization, thermal investigation and antimicrobial activity

    NASA Astrophysics Data System (ADS)

    Abd El-Wahab, Zeinab H.

    2007-05-01

    Two Schiff base ligands bearing organic acid moiety, vis., N-(2-thienylmethylidene)-2-amino-4-chlorobenzoic acid (HL 1) and N-(2-hydroxybenzylidene)-2-amino-4-chlorobenzoic acid (H 2L 2) have been synthesized by the interaction of 2-thiophenecarboxaldehyde and 2-hydroxybenzaldehyde with 2-amino-4-chlorobenzoic acid. Co(II), Ni(II), Cu(II) and Zn(II) complexes of these ligands have been prepared. They are characterized on the basis of analytical data, molar conductance, IR, 1H NMR, UV-vis, mass spectra, magnetic measurements, thermal analysis and X-ray powder diffraction technique. The molar conductance data reveal that these complexes are non-electrolytes. The ligands are coordinated to the metal ions in a terdentate manner with ONO/ONS donor sites of the carbonyl oxygen, azomethine nitrogen and phenolic oxygen or thiophenic sulphur. An octahedral structure is proposed for the prepared metal complexes and some ligand field parameters ( Dq, B and β) in addition to CFSE were calculated. The thermal stability of the metal complexes is evaluated. The Schiff base ligands and their metal complexes have been tested against four species of bacteria as well as four species of fungi and the results have been compared with some known antibiotics.

  3. The chitosan-gelatin (bio)polyelectrolyte complexes formation in an acidic medium.

    PubMed

    Voron'ko, Nicolay G; Derkach, Svetlana R; Kuchina, Yuliya A; Sokolan, Nina I

    2016-03-15

    The interaction of cationic polysaccharide chitosan and gelatin accompanied by the stoichiometric (bio)polyelectrolyte complexes formation has been studied by the methods of capillary viscometry, UV and FTIR spectroscopy and dispersion of light scattering. Complexes were formed in the aqueous phase, with pH being less than the isoelectric point of gelatin (pIgel). The particle size of the disperse phase increases along with the growth of the relative viscosity in comparison with sols of the individual components-polysaccharide and gelatin. Possible models and mechanism of (bio)polyelectrolyte complexes formation have been discussed. It was shown that the complex formation takes place not only due to the hydrogen bonds, but also due to the electrostatic interactions between the positively charged amino-groups of chitosan and negatively charged amino acid residues (glutamic Glu and aspartic Asp acids) of gelatin. PMID:26794762

  4. 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.

  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. 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

  7. Cleavage of chromatin with methidiumpropyl-EDTA . iron(II).

    PubMed Central

    Cartwright, I L; Hertzberg, R P; Dervan, P B; Elgin, S C

    1983-01-01

    Methidiumpropyl-EDTA . iron(II) [MPE . Fe (II)] cleaves double-helical DNA with considerably lower sequence specificity than micrococcal nuclease. Moreover, digestions with MPE . Fe(II) can be performed in the presence of certain metal chelators, which will minimize the action of many endogenous nucleases. Because of these properties MPE . Fe(II) would appear to be a superior tool for probing chromatin structure. We have compared the patterns generated from the 1.688 g/cm3 complex satellite, 5S ribosomal RNA, and histone gene sequences of Drosophila melanogaster chromatin and protein-free DNA by MPE . Fe(II) and micrococcal nuclease cleavage. MPE . Fe(II) at low concentrations recognizes the nucleosome array, efficiently introducing a regular series of single-stranded (and some double-stranded) cleavages in chromatin DNA. Subsequent S1 nuclease digestion of the purified DNA produces a typical extended oligonucleosome pattern, with a repeating unit of ca. 190 base pairs. Under suitable conditions, relatively little other nicking is observed. Unlike micrococcal nuclease, which has a noticeable sequence preference in introducing cleavages, MPE . Fe(II) cleaves protein-free tandemly repetitive satellite and 5S DNA sequences in a near-random fashion. The spacing of cleavage sites in chromatin, however, bears a direct relationship to the length of the respective sequence repeats. In the case of the histone gene sequences a faint, but detectable, MPE . Fe(II) cleavage pattern is observed on DNA, in some regions similar to and in some regions different from the strong chromatin-specified pattern. The results indicate that MPE . Fe(II) will be very useful in the analysis of chromatin structure. Images PMID:6407008

  8. Synthesis and spectroscopic studies of iron (III) complex with a quinolone family member (pipemidic acid)

    NASA Astrophysics Data System (ADS)

    Skrzypek, D.; Szymanska, B.; Kovala-Demertzi, Dimitra; Wiecek, Joanna; Talik, E.; Demertzis, Mavroudis A.

    2006-12-01

    The interaction of iron (III) with pipemidic acid, Hpipem, afforded the complex [Fe (pipem) (HO)2 (H2O)]2. The new complex has been characterised by elemental analyses, infra-red, EPR and XPS spectroscopies. The monoanion, pipem, exhibits O, O ligation through the carbonyl and carboxylato oxygen atoms. Six coordinate dimer distorted octahedral configuration has been proposed for [Fe (pipem) (HO)2 (H2O)]2.

  9. Hydrolysis of oxaliplatin-evaluation of the acid dissociation constant for the oxalato monodentate complex.

    PubMed

    Jerremalm, Elin; Eksborg, Staffan; Ehrsson, Hans

    2003-02-01

    Alkaline hydrolysis of the platinum anticancer drug oxaliplatin gives the oxalato monodentate complex and the dihydrated oxaliplatin complex in two consecutive steps. The acid dissociation constant for the oxalato monodentate intermediate was determined by a kinetic approach. The pK(a) value was estimated as 7.23. The monodentate intermediate is assumed to rapidly react with endogenous compounds, resulting in a continuous conversion of oxaliplatin via the monodentate form. PMID:12532393

  10. Arsenic speciation and identification of monomethylarsonous acid and monomethylthioarsonic acid in a complex matrix.

    PubMed

    Yathavakilla, Santha Ketavarapu V; Fricke, Michael; Creed, Patricia A; Heitkemper, Douglas T; Shockey, Nohora V; Schwegel, Carol; Caruso, Joseph A; Creed, John T

    2008-02-01

    Anion-exchange chromatography was utilized for speciation of arsenite (As(III)), arsenate (As(V)), dimethylarsinic acid (DMA(V)), monomethylarsonic acid (MMA(V)), monomethylarsonous acid (MMA(III)), and the new As species monomethylthioarsonic acid (MMTA), using inductively coupled plasma mass spectrometric (ICPMS) detection. MMA(III) and MMTA were identified for the first time in freeze-dried carrot samples that were collected over 25 years ago as part of a joint U.S. EPA, U.S. FDA, and USDA study on trace elements in agricultural crops. The discovery of MMA(III) and MMTA in terrestrial foods necessitated the analytical characterization of synthetic standards of both species, which were used for standard addition in carrot extracts. The negative ion mode, high-resolution electrospray mass spectrometry (HR-ESI-MS) data produced molecular ions of m/z 122.9418 and 154.9152 for MMA(III) and MMTA, respectively. However, ESI-MS was not sensitive enough to directly identify MMA(III) and MMTA in the carrot extracts. Therefore, to further substantiate the identification of MMA(III) and MMTA, two additional separations using an Ion-120 column were developed using the more sensitive ICPMS detection. The first separation used 20 mM tetramethylammonium hydroxide at pH 12.2 with MMA(III) eluting in less than 7 min. In the second separation, MMTA eluted at 11.2 min by utilizing 40 mM ammonium carbonate at pH 9.0. Oxidation of MMA(III) and MMTA to MMA(V) with hydrogen peroxide was observed for standards and carrot extracts alike. Several samples of carrots collected from local markets in 2006 were also analyzed and found to contain low levels of inorganic arsenic species. PMID:18181583

  11. Determination of complex formation constants by phase sensitive alternating current polarography: Cadmium-polymethacrylic acid and cadmium-polygalacturonic acid.

    PubMed

    Garrigosa, Anna Maria; Gusmão, Rui; Ariño, Cristina; Díaz-Cruz, José Manuel; Esteban, Miquel

    2007-10-15

    The use of phase sensitive alternating current polarography (ACP) for the evaluation of complex formation constants of systems where electrodic adsorption is present has been proposed. The applicability of the technique implies the previous selection of the phase angle where contribution of capacitive current is minimized. This is made using Multivariate Curve Resolution by Alternating Least Squares (MCR-ALS) in the analysis of ACP measurements at different phase angles. The method is checked by the study of the complexation of Cd by polymethacrylic (PMA) and polygalacturonic (PGA) acids, and the optimal phase angles have been ca. -10 degrees for Cd-PMA and ca. -15 degrees for Cd-PGA systems. The goodness of phase sensitive ACP has been demonstrated comparing the determined complex formation constants with those obtained by reverse pulse polarography, a technique that minimizes the electrode adsorption effects on the measured currents. PMID:19073101

  12. 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

  13. EDTA-induced pseudothrombocytopenia in association with bladder cancer

    PubMed Central

    Sahin, Cem; Kırlı, Ismail; Sozen, Hamdi; Canbek, Tugba Dibektas

    2014-01-01

    Pseudothrombocytopenia is the detection of low platelet counts by an autoanalyser despite lack of shortage in platelets. EDTA-induced pseudothrombocytopenia, the most frequently seen form in clinical practice, occurs mainly due to reaction of antiplatelet antibodies. Pseudothrombocytopenia is not only seen in healthy individuals but it is also reported in association with autoimmune, cardiovascular and liver parenchyma diseases and malignancy. We aimed to review approaches to pseudothrombocytopenia by presenting a case in which EDTA-dependent thrombocytopenia in association with bladder tumour was detected during examination for haematuria. PMID:24951601

  14. Chitosan-poly(acrylic) acid polyionic complex: in vivo study to demonstrate prolonged gastric retention.

    PubMed

    Torrado, Susana; Prada, Pablo; de la Torre, Paloma M; Torrado, Santiago

    2004-02-01

    The aim of this study was to develop a chitosan-poly(acrylic) acid based controlled drug release system for gastric antibiotic delivery. Different mixtures of amoxicillin (A), chitosan (CS), and poly(acrylic) acid (PAA) were employed to obtain these polyionic complexes. A non-invasive method was employed for determining the gastric residence time of the formulations. It was studied the swelling behavior and drug release from these complexes. Gastric emptying rate study was performed by means of the [13C]octanoic acid breath test. The gastric emptying rates of two different formulations (conventional and gastric retentive system) were studied. Swelling studies indicated that the extent of swelling was greater in the polyionic complexes than in the single chitosan formulations. The amoxicillin diffusion from the hydrogels was controlled by the polymer/drug interaction. The property of these complexes to control the solute diffusion depends on the network mesh size, which is a significant factor in the overall behavior of the hydrogels. The gastric half-emptying time of the polyionic complex was significantly delayed compared to the reference formulation, showing mean values of 164.32+/-26.72 and 65.06+/-11.50min, respectively (P<0.01). The results of this study suggest that, these polyionic complexes are good systems for specific gastric drug delivery. PMID:14609680

  15. A convenient method for the preparation of barbituric and thiobarbituric acid transition metal complexes.

    PubMed

    Refat, Moamen S; El-Korashy, Sabry A; Ahmed, Ahmed S

    2008-12-01

    A convenient method for the preparation of barbiturate transition metal complexes: (i) Cr(3+), Mn(2+), Fe(3+), Zn(2+) and Cd(2+) ions with barbituric acid (H(2)L) and (ii) Cr(3+) and Mo(5+) with 2-thiobarbituric acid (H(2)L') was reported and this has enabled seven complexes to be formulated as: [Cr(HL)(2)(OH)(H(2)O)].H(2)O, [Mn(HL)(2)(H(2)O)(2)], [Fe(2)(L)(OH)(3)(H(2)O)(4)].2H(2)O, [Zn(HL)(2)], [Cd(HL)(2)], [Cr(HL')(OH)(2)(H(2)O)].H(2)O and [Mo(HL')(2)]Cl. These new barbiturate complexes were synthesized and characterized by elemental analysis, molar conductivity, magnetic measurements, spectral methods (mid infrared, (1)H NMR, mass, X-ray powder diffraction and UV/vis spectra) and simultaneous thermal analysis (TG and DTG) techniques. The molar conductance measurements proved that, all complexes of barbituric and 2-thiobarbituric acids are non-electrolytes except for [Mo(HL')(2)]Cl. The electronic spectra and magnetic susceptibility measurements were used to infer the structures. The IR spectra of the ligands and their complexes are used to identify the mode of coordination. Kinetic and thermodynamic parameters such as: E, DeltaH, DeltaS and DeltaG are estimated according to the DTG curves. The two ligands and their complexes have been studied for their possible biological antifungal activity. PMID:18420451

  16. 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.

  17. 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.

  18. 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.

  19. 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.

  20. [The favorable effect of humic acid based complex micro-element preparations in cadmium exposure].

    PubMed

    Hudák, A; Náray, M; Nagy, I; Molnár, M; Gömöry, I; Ungváry, G

    1997-06-01

    The authors have studied the effect of consumption of a humic acid based complex microelement preparation (potassium, magnesium, iron, zinc, manganese, copper, vanadium, cobalt, molibden, selenium bound to humic acids) for six weeks (10 ml daily) on the biological exposure indices (blood and urine cadmium levels) and clinical laboratory parameters (liver and kidney tests, blood picture) of men (n = 18; 39.7 +/- 10.4 years of age;) working in cadmium exposure for 8.3 +/- 5.0 years. The initial mean blood and urine cadmium levels of the non-smoking subjects was twice higher than that of the non-smoking male controls living in the same urban area (n = 35), and significantly correlated with the length of exposure. Their mean serum alanin-aminotransferase, gamma-glutamyl-transferase, creatinine, uric acid and urinary N-acetyl-beta-D-glucosaminidase levels were significantly higher than that of the controls. After the six-week treatment blood cadmium level, activity of serum alanin-aminotransferase, serum uric acid and urinary protein concentrations decreased significantly, the abnormal serum iron levels normalized. According to this results, the absorption of cadmium decreased on the effect of the complex microelement supplementation and the adverse laboratory changes attributable partly to cadmium exposure improved. Therefore humic acid based complex microelement supplementation is recommended as an effective tool for prevention and health protection in occupational cadmium exposure as well as for smokers known to be considerably burdened by cadmium. PMID:9254361

  1. PHOTODEGRADATION OF A TERNARY IRON(III)-URANIUM(VI)-CITRIC ACID COMPLEX

    EPA Science Inventory

    The mechanisms of photodegradation of binary iron- and uranium-citrate and ternary iron-uranium-citrate complexes were elucidated. Citric acid degradation products were identified by HPLC and GC, and the metal precipitates were identified by XRD and EXAFS. Photodegradation of a b...

  2. 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

  3. Hydrolysis of phosphodiesters by diiron complexes: design of nonequivalent iron sites in purple acid phosphatase models.

    PubMed

    Verge, François; Lebrun, Colette; Fontecave, Marc; Ménage, Stéphane

    2003-01-27

    New mu-oxo-diferric complexes have been designed for hydrolysis of phosphodiesters. To mimic the diiron active site of purple acid phosphatase, a combinatorial method has been used to select complexes containing two distinct iron coordination spheres. The introduction of a bidentate ligand, a substituted phenanthroline (L) into complex 1, [Fe2O(bipy)4(OH2)2](NO3)4, generates in solution the complex [Fe2O(bipy)3(L)(OH2)2](NO3)4 as shown by ESI/MS and 1H NMR studies. The latter complex was found to be 20-fold more active than complex 1. On the basis of kinetic studies, we demonstrated that the complex [Fe2O(bipy)3(L)(OH)(OH2)](NO3)3 was the active species and the reaction proceeded through the formation of a ternary complex in which one iron binds a hydroxide and the second, the substrate. At nonsaturating concentrations of the substrate, the increased activity with increased methyl substituents in L was due to an increased affinity of the complex for the substrate. The activity of [Fe2O(bipy)3(33'44'Me2-Phen)(OH2)2](NO3)4 [33'44'Me2Phen = 3,3',4,4'-dimethyl-1,10-phenanthroline] was found to be comparable to that reported for Co(III) or Ce(IV) complexes. PMID:12693232

  4. Extraction of pyridines into fluorous solvents based on hydrogen bond complex formation with carboxylic acid receptors.

    PubMed

    O'Neal, Kristi L; Geib, Steven; Weber, Stephen G

    2007-04-15

    A molecular receptor embedded in a 'poor-solvent' receiving phase, such as a fluorous phase, should offer the ideal medium for selective extraction and sensing. The limited solubility of most solutes in fluorous phases enhances selectivity by reducing the extraction of unwanted matrix components. Thus, receptor-doped fluorous phases may be ideal extraction media. Unfortunately, sufficient data do not exist to judge the capability of this approach. The solubilities of very few nonfluorous solutes are known. As far as we are aware, such important quantities as the strength of a hydrogen bond in a fluorous environment are not known. Thus, it is currently impossible to predict whether a particular receptor/solute complex based on a particular set of noncovalent interactions will provide enough thermodynamic stabilization to extract the solute into the fluorous phase. In this work, fluorous carboxylic acids (a carboxylic acid-terminated perfluoropolypropylene oxide called Krytox and perfluorodecanoic acid (PFDA)) were used as receptors and substituted pyridines as solutes to show that the fluorous receptor dramatically enhances the liquid-liquid extraction of the polar substrates from chloroform into perfluorohexanes. The method of continuous variations was used to determine the receptor-pyridine complex stoichiometry of 3:1. The free energies of formation of the 3:1 complexes from one pyridine and 3/2 H-bonded cyclic dimers of the fluorous carboxylic acid are -30.4 (Krytox) and -37.3 kJ mol-1 (PFDA). The free energy required to dissociate the dimer in perfluorohexanes is +16.5 kJ mol-1 (Krytox). The crystal structure of the complex showed a 1:1 stoichiometry with a mixed strong-weak hydrogen-bonded motif. Based on the stoichiometry, crystal structure, and UV and IR spectroscopic shifts, we propose that the 3:1 complex has four hydrogen bonds and the carboxylic acid transfers a proton to pyridine. The resulting pyridinium carboxylate N+H-O- hydrogen bond is accompanied

  5. 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.

  6. Pilot-scale washing of metal contaminated garden soil using EDTA.

    PubMed

    Voglar, David; Lestan, Domen

    2012-05-15

    Ten batches (75kg each) of garden soil with >50% of silt and clay and average 1935mgkg(-1) Pb, 800mgkg(-1) Zn, 10mgkg(-1) Cd and 120mgkg(-1) As were remediated in a pilot-scale chemical extraction plant. Washing with 60mmol ethylenediaminetetraacetic acid (EDTA) per kg of soil on average removed 79, 38, 70, and 80% of Pb, Zn, Cd and As, respectively, and significantly reduced the leachability, phyto-accessibility and oral-availability of residual toxic metals, as assessed using deionised water, toxicity characteristic leaching procedure (TCLP), diethylenetriamine pentaacetic acid extraction (DTPA) and physiologically based extraction test (PBET) tests. The used soil washing solution was treated before discharge using an electrochemical advanced oxidation process with graphite anode: EDTA was removed by degradation and toxic metals were electro-precipitated onto a stainless steel cathode. The novelty of the remediation technique is separation of the soil from the washing solution and soil rinsing (removal of mobilized contaminants) carried out in the same process step. Another novelty is the reuse of the soil rinsing solution from the previous batch for cleansing the soil sand, soil rinsing and for preparation of the washing solution in subsequent batches. The cost of energy and material expenses and disposal of waste products amounted to approximately 75€ton(-1) of soil. PMID:22410723

  7. 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.

  8. Cytoxicity and Apoptotic Mechanism of Ruthenium(II) Amino Acid Complexes in Sarcoma-180 Tumor Cells

    PubMed Central

    Lima, Aliny Pereira; Pereira, Flávia Castro; Almeida, Marcio Aurelio Pinheiro; Mello, Francyelli Mariana Santos; Pires, Wanessa Carvalho; Pinto, Thallita Monteiro; Delella, Flávia Karina; Felisbino, Sérgio Luis; Moreno, Virtudes; Batista, Alzir Azevedo; de Paula Silveira-Lacerda, Elisângela

    2014-01-01

    Over the past several decades, much attention has been focused on ruthenium complexes in antitumor therapy. Ruthenium is a transition metal that possesses several advantages for rational antitumor drug design and biological applications. In the present study, five ruthenium complexes containing amino acids were studied in vitro to determine their biological activity against sarcoma-180 tumor cells. The cytotoxicity of the complexes was evaluated by an MTT assay, and their mechanism of action was investigated. The results demonstrated that the five complexes inhibited the growth of the S180 tumor cell line, with IC50 values ranging from 22.53 µM to 50.18 µM, and showed low cytotoxicity against normal L929 fibroblast cells. Flow cytometric analysis revealed that the [Ru(gly)(bipy)(dppb)]PF6 complex (2) inhibited the growth of the tumor cells by inducing apoptosis, as evidenced by an increased number of Annexin V-positive cells and G0/G1 phase cell cycle arrest. Further investigation showed that complex 2 caused a loss of mitochondrial membrane potential; activated caspases 3, caspase-8, and caspase-9 and caused a change in the mRNA expression levels of caspase 3, caspase-9 as well as the bax genes. The levels of the pro-apoptotic Bcl-2 family protein Bak were increased. Thus, we demonstrated that ruthenium amino acid complexes are promising drugs against S180 tumor cells, and we recommend further investigations of their role as chemotherapeutic agents for sarcomas. PMID:25329644

  9. 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

  10. 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.

  11. 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. PMID:26237660

  12. 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

  13. 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.

  14. Intermolecular hydrogen bond complexes by in situ charge transfer complexation of o-tolidine with picric and chloranilic acids

    NASA Astrophysics Data System (ADS)

    Refat, Moamen S.; Saad, Hosam A.; Adam, Abdel Majid A.

    2011-08-01

    A two new charge transfer complexes formed from the interactions between o-tolidine (o-TOL) and picric (PA) or chloranilic (CA) acids, with the compositions, [(o-TOL)(PA) 2] and [(o-TOL)(CA) 2] have been prepared. The 13C NMR, 1H NMR, 1H-Cosy, and IR show that the charge-transfer chelation occurs via the formation of chain structures O-H⋯N intermolecular hydrogen bond between 2NH 2 groups of o-TOL molecule and OH group in each PA or CA units. Photometric titration measurements concerning the two reactions in methanol were performed and the measurements show that the donor-acceptor molar ratio was found to be 1:2 using the modified Benesi-Hildebrand equation. The spectroscopic data were discussed in terms of formation constant, molar extinction coefficient, oscillator strength, dipole moment, standard free energy, and ionization potential. Thermal behavior of both charge transfer complexes showed that the complexes were more stable than their parents. The thermodynamic parameters were estimated from the differential thermogravimetric curves. The results indicated that the formation of molecular charge transfer complexes is spontaneous and endothermic.

  15. Peat humic acids and their complex forming properties as influenced by peat humification

    NASA Astrophysics Data System (ADS)

    Dudare, D.; Klavins, M.

    2012-04-01

    To study paleoenvironmental changes of importance is understanding of processes of organic matter diagenesis, especially changes of refractory part of natural organic substances - humic substances. Studies of the living organic matter humification process are also essential for understanding of the carbon biogeochemical cycle. The aim of this study was to analyze peat organic matter diagenesis: changes of properties of humic acids, relations between the humification process, properties of peat, peat humic acids, their ability to interact with metal ions, as well ability to accumulate metals. The analysis were carried out on samples of humic substances preparatively extracted from three ombrotrophic bog peat profiles to identify the links between peat age, decomposition and humification degree, botanical composition and properties of peat humic acids elemental (C, H, N, O), functional (-COOH, -OH) composition, structural characteristics - UV, fluorescence, FTIR. The found variability of peat properties is less significant than differences in the properties of peat-forming living matter, thus revealing the dominant impact of humification process on the properties of peat. Correspondingly, composition of peat humic acids is little affected by differences in the properties of precursor living organic material, and such indicators as decomposition degree, humification degree, humic acid elemental ratio and concentrations of acidic functional groups are the best descriptors of changes in organic matter during the process of organic matter diagenesis and humification. Peat ability to accumulate major and trace elements depends on the character of element supply, potency of metal ions to bind functionalities in the peat, with an emphasis on the structure of peat humic acid, pH reaction, oxygen presence, presence of complexing compounds, inorganic ions and many other factors. Major and trace element presence in peat is of importance as an indicator of peat genesis and

  16. 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

  17. Olfactory discrimination of complex mixtures of amino acids by the black bullhead Ameiurus melas.

    PubMed

    Valentincic, T; Miklavc, P; Kralj, S; Zgonik, V

    2011-07-01

    On the basis of previous findings of behavioural discrimination of amino acids and on the knowledge of electrophysiology of the catfish (genera Ictalurus and Ameiurus) olfactory organs, behavioural experiments that investigated olfactory discrimination of amino acid mixtures were carried out on the black bullhead Ameiurus melas. Repeated presentations of food-rewarded mixtures released increased swimming activity measured by counting the number of turns >90° within 90 s of stimulus addition. Non-rewarded amino acids and their mixtures released little swimming activity, indicating that A. melas discriminated between the conditioned and the non-conditioned stimuli. Two questions of mixture discrimination were addressed: (1) Are A. melas able to detect components within simple and complex amino acid mixtures? (2) What are the smallest differences between two complex mixtures that A. melas can detect? Three and 13 component mixtures tested were composed primarily of equipotent amino acids [determined by equal electroolfactogram (EOG) amplitude] that contained L-Cys at ×100 the equipotent concentration. Ameiurus melas initially perceived the ternary amino acid mixture as its more stimulatory component alone [i.e. cysteine (Cys)], whereas the conditioned 13 component mixture containing the more stimulatory L-Cys was perceived immediately as different from L-Cys alone. The results indicate that components of ternary mixtures are detectable by A. melas but not those of more complex mixtures. To test for the smallest detectable differences in composition between similar multimixtures, all mixture components were equipotent. Initially, A. melas were unable to discriminate the mixtures of six amino acids from the conditioned mixtures of seven amino acids, whereas they discriminated immediately the mixtures of four and five amino acids from the conditioned mixture. Experience with dissimilar mixtures enabled the A. melas to start discriminating the seven

  18. 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

  19. 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. PMID:26780577

  20. 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)

  1. 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

  2. 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.

  3. 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...

  4. 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

  5. [Molluscacide activity of a mixture of 6-n-alkyl salicylic acids (anacardic acid) and 2 of its complexes with copper (II) and lead (II)].

    PubMed

    Mendes, N M; de Oliveira, A B; Guimarães, J E; Pereira, J P; Katz, N

    1990-01-01

    The molluscicide activity of hexanic extract from Anacardium occidentale L. (cashew) nut shell, of copper (II) complex, of lead (II) complex and anacardic acid has been compared in the laboratory in an attempt to obtain better stability than anacardic acid. This was obtained from the hexanic extract of the cashew nut shell by precipitation with lead (II) hydroxide or cupric sulfate plus sodium hydroxide or (II) cupric hydroxide followed by treatment of lead (II) complex with a diluted solution of sulfuric acid. Ten products of the mixture obtained were tested on adults snails of Biomphalaria glabrata at 1 to 10 ppm. The most active products were copper (II) complex, obtained by cupric sulfate plus sodium hydroxide, and anacardic acid (sodium hydroxide) which presented activity at 4 ppm. The anacardic acid's lead content was above the limits accepted by the United States standards. PMID:2133588

  6. 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.

  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. PMID:25985927

  8. Complexations of polyoligothiophenes films with transition metals, and their use for electrocatalysis of ascorbic acid

    NASA Astrophysics Data System (ADS)

    Maouche, N.; Chelli, S.; Nessark, B.; Aeiyach, S.

    2009-11-01

    Chemically modified electrodes prepared by electropolymerization of oligothiophenes such as: 2,2'-bithiophene (BT), 2,2'-bithiophene-5-carboxylic acid (BTCA) and terthiophene aldehyde (TTCHO) on platinum (Pt) electrodes, in acetonitrile solution containing 0.1 M tetrabutylammonium perchlorate (TBAP) and 0.01 M of monomer, are characterized by cyclic volammetry (CV), and X-ray photoelectron spectroscopy (XPS) measurements. By immersing the prepared modified electrodes in transition metals (Cu2+, Co2+ and Ag+) solutions, the metal ions were complexed with films. The electrochemical response shows clearly, the presence of oxidation and reduction peaks corresponding to metallic couple redox. XPS technique reveal that the films complexed with metal ions and determine the mode of the connection with film's atoms. The obtained polyoligothiophenes-metal modified electrodes exhibited good electrocatalytic properties towards ascorbic acid (AA) oxidation after their complexation with metallic ions. The electrocatalytic response was evaluated by cyclic voltammetry with regard to the film nature, the metallic ion nature, immersion time, ascorbic acid concentration, and other variables. The results reveal that the catalytic activity of Ag+ complexed with BTCA thin-film is the best toward AA oxidation and it can be detected a very low concentration (∼1 μM), of AA in a solution which can be utilized as an efficient electrochemical sensor.

  9. Spectrophotometric study of the charge transfer complex between 2-amino-4-picoline with chloranilic acid

    NASA Astrophysics Data System (ADS)

    Alghanmi, Reem M.; Al-Attas, Amirah S.; Habeeb, Moustafa M.

    2013-02-01

    Charge transfer complex formation between 2-amino-4-picoline (2A4P) as the electron donor with chloranilic acid (CLA) as the electron acceptor has been studied spectrophotometrically in different polar solvents included acetone (AcN), ethanol (EtOH) and acetonitrile (AN). The molecular composition of the formed complex was recognized utilizing Job's, photometric and conductometric titration methods to be 1:1. The formation constants and molecular extinction coefficients were estimated using Benesi-Hildebrand equation; they recorded high values confirming high stability of the formed complex. Moreover, the results showed that the complex is more stable in acetone with lower electric permittivity compared with ethanol or acetonitrile of higher ones. The values of some spectroscopic physical parameters like oscillator strength f, transition dipole moment μ, resonance energy RN, charge transfer energy ECT, dissociation energy W, ionization potential IP and standard free energy ΔGo were determined and evaluated. The solid complex was isolated and its molecular composition was determined by elemental analysis to be 1:1. Furthermore, the solid complex was characterized using FTIR and 1H NMR measurements. They confirmed the presence of proton transfer beside charge transfer in the obtained complex. Molecular orbital calculations utilizing GAMESS computations were carried out to predict infrared spectra. They also confirmed the presence of proton transfer beside charge transfer in the formed complex.

  10. Protic Acid Hydrogen Bonding in Chlorofluoroethylenes: the Hydrogen Fluoride-Vinyl Chloride Complex

    NASA Astrophysics Data System (ADS)

    Leung, Helen O.; Marshall, Mark D.

    2012-06-01

    Our studies of intermolecular complexes formed in the gas phase between protic acids (HX) and chlorofluoroethylene complexes to date have demonstrated a preference for HX binding to a F atom over hydrogen bond formation with the Cl atom. Ab initio calculations suggest that this may not be true for species with an increased degree of halogen substitution on the ethylene. To characterize the nature of hydrogen bond formation with the less electronegative, but more polarizable Cl atom, we have obtained the microwave spectrum of HF-vinyl chloride complex. Analysis of the spectra for the 35Cl and 37Cl isotopologues demonstrate that the complex is planar and provides structural parameters for this species. This allows comparisons to be made between the HX hydrogen bond to Cl and that to F.

  11. 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

  12. Ruthenium(II) multi carboxylic acid complexes: chemistry and application in dye sensitized solar cells.

    PubMed

    Shahroosvand, Hashem; Nasouti, Fahimeh; Sousaraei, Ahmad

    2014-04-01

    Novel ruthenium multi carboxylic complexes (RMCCs) have been synthesized by using ruthenium nitrosyl nitrate, 1,2,4,5-benzenetetracarboxylic acid (H4btec) and 4,7-diphenyl-1,10-phenanthroline (BPhen) as photosensitizers for titanium dioxide semiconductor solar cells. The complexes were characterized by (1)H-NMR, FT-IR, UV-Vis, ICP and CHN analyses. The reaction details and features were then described. SEM analysis revealed that the penetration of dyes into the pores of the nanocrystalline TiO2 surface was improved by increasing the number of btec units. The solar energy to electricity conversion efficiency of complexes shows that the number of attached carboxylates on a dye has an influence on the photoelectrochemical properties of the dye-sensitized electrode. An incident photon-to-current conversion efficiency (IPCE) of 13% at 510 nm was obtained for ruthenium complexes with three btec units. PMID:24500312

  13. Hyaluronic acid-siRNA conjugate/reducible polyethylenimine complexes for targeted siRNA delivery.

    PubMed

    Jang, Yeon Lim; Ku, Sook Hee; Jin, So; Park, Jae Hyung; Kim, Won Jong; Kwon, Ick Chan; Kim, Sun Hwa; Jeong, Ji Hoon

    2014-10-01

    The clinical applications of therapeutic siRNA remain as a challenge due to the lack of efficient delivery system. In the present study, hyaluronic acid-siRNA conjugate (HA-SS-siRNA)/reducible polyethylenimine (BPEI1.2k-SS) complexes were developed to efficiently deliver the siRNA to HA receptor abundant region with the improved siRNA stability. HA and siRNA were conjugated with disulfide bonds, which are cleavable in cytoplasm. The synthesized HA-SS-siRNA was further complexed with BPEI1.2k-SS, resulting in the formation of spherical nanostructures with approximately 190 nm of size and neutral surface charge. HA-SS-siRNA/BPEI1.2k-SS complexes exhibited the improved stability against serum proteins or polyanions. These complexes were successfully translocated into intracellular region via HA receptor-mediated endocytosis, and silenced target gene expression. PMID:25942799

  14. 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.

  15. Replacing electrolytic iron in a fortification-mix with NaFeEDTA increases both iron and zinc availabilities in traditional African maize porridges.

    PubMed

    Kruger, Johanita

    2016-08-15

    While replacing electrolytic iron with NaFeEDTA in multi-micronutrient fortification-mixes is a popular option, there is no information about the effect on the iron and zinc availabilities in African staple foods. This study evaluated the effects of adding a multi-micronutrient fortification-mix, with no iron, electrolytic iron or NaFeEDTA on the availabilities of iron and zinc from thick and fermented special-grade maize porridges using a Caco-2 cell model. Replacing electrolytic iron with NaFeEDTA significantly (p ⩽ 0.05) increased iron and, importantly zinc, availabilities in both the thick (2.16% vs. 1.45% and 2.51% vs. 2.29%, respectively) and fermented (3.35% vs. 2.66% and 3.04% vs. 2.61%, respectively) porridges. Some of the NaFeEDTA complexes perhaps partially dissociated because of pH changes during simulated digestion, binding with zinc and increasing its availability. NaFeEDTA in a multi-micronutrient fortification-mix, added to less refined, high phytate maize meal, would be more effective than electrolytic iron in addressing both iron and zinc deficiencies in low socio-economic populations of sub-Saharan Africa. PMID:27006207

  16. Luminescence properties of [Ru(bpy) 2MDHIP] 2+ modulated by the introduction of DNA, copper(II) ion and EDTA

    NASA Astrophysics Data System (ADS)

    Chen, Miaojing; Li, Hong; Li, Qian; Xu, Zhenghe

    2010-05-01

    The luminescence properties of [Ru(bpy) 2MDHIP] 2+ (bpy = 2,2'-bipyridine, MDHIP = 2,4-dihydrophenyl-imidazo[4,5-f][1,10]phenanthroline) in the absence and presence of DNA modulated by the introduction of Cu 2+ ion and EDTA have been investigated. It is found that the ruthenium(II) complex can insert and stack between the base pairs of calf thymus DNA with MDHIP ligand, and the intramolecular hydrogen bond is located inside of the DNA. The presence of DNA can enhance the luminescence intensities of [Ru(bpy) 2MDHIP] 2+ both in buffer solution and on an ITO surface. Moreover, the luminescence intensities of [Ru(bpy) 2MDHIP] 2+ and DNA-bound [Ru(bpy) 2MDHIP] 2+ are quenched by Cu 2+, and next recovered by the addition of EDTA. The repetitive luminescence-modulations have been achieved through the introduction of equimolar Cu 2+ and EDTA, respectively. In addition, it becomes evident that the number of luminescence-modulation cycles for [Ru(bpy) 2MDHIP] 2+ in the absence and presence of DNA is influenced by the cumulative concentrations of CuEDTA, generated successively by the strong coordination of Cu 2+ to EDTA.

  17. 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

  18. Branched-chain amino acids complex inhibits melanogenesis in B16F0 melanoma cells.

    PubMed

    Cha, Jae-Young; Yang, Hyun-Ju; Moon, Hyung-In; Cho, Young-Su

    2012-04-01

    Present study was investigated the effect of each or complex of three branched-chain amino acids (BCAAs; isoleucine, leucine, and valine) on melanin production in B16F0 melanoma cells treated with various concentrations (1-16 mM) for 72 h. Among the 20 amino acids, lysine and glycine showed the highest activities of DPPH radical scavenging and mushroom tyrosinase inhibition, respectively. Each and combination of BCAAs reduced melanogenesis in a concentration-dependent manner without any morphological changes and cell viability in melanoma cells. Present study was also investigated the inhibitory effects of each or complex of BCAAs at each 10 mM concentration on the 100 μM IBMX-mediated stimulation of melanogenesis in melanoma cells for 72 h and found that IBMX treatment was stimulated to enhance melanin synthesis and that the complex of BCAAs was the most effectively inhibited in the melanin amounts of cellular and extracellular and the whitening the cell pellet. When the inhibitory effect of BCAAs on tyrosinase was examined by intracellular tyrosinase assay, both isoleucine and valine exhibit slightly inhibition, but leucine and combination of BCAAs did not inhibit the cell-derived tyrosinase activity. Present study demonstrated that complex of BCAAs inhibited melanin production without changes intercellular tyrosinase activity. Thus, the complex of BCAAs may be used in development of safe potentially depigmenting agents. PMID:21854182

  19. 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

  20. Inhibition of acid, alkaline, and tyrosine (PTP1B) phosphatases by novel vanadium complexes.

    PubMed

    McLauchlan, Craig C; Hooker, Jaqueline D; Jones, Marjorie A; Dymon, Zaneta; Backhus, Emily A; Greiner, Bradley A; Dorner, Nicole A; Youkhana, Mary A; Manus, Lisa M

    2010-03-01

    In the course of our investigations of vanadium-containing complexes for use as insulin-enhancing agents, we have generated a series of novel vanadium coordination complexes with bidentate ligands. Specifically we have focused on two ligands: anthranilate (anc(-)), a natural metabolite of tryptophan, and imidizole-4-carboxylate (imc(-)), meant to mimic naturally occurring N-donor ligands. For each ligand, we have generated a series of complexes containing the V(III), V(IV), and V(V) oxidation states. Each complex was investigated using phosphatase inhibition studies of three different phosphatases (acid, alkaline, and tyrosine (PTP1B) phosphatase) as prima facia evidence for potential use as an insulin-enhancing agent. Using p-nitrophenyl phosphate as an artificial phosphatase substrate, the levels of inhibition were determined by measuring the absorbance of the product at 405nm using UV/vis spectroscopy. Under our experimental conditions, for instance, V(imc)(3) appears to be as potent an inhibitor of alkaline phosphatase as sodium orthovanadate when comparing the K(cat)/K(m) term. VO(anc)(2) is as potent an inhibitor of acid phosphatase and tyrosine phosphatase as the Na(3)VO(4). Thus, use of these complexes can increase our mechanistic understanding of the effects of vanadium in vivo. PMID:20071031

  1. First fluorescence spectroscopic investigation of Am(III) complexation with an organic carboxylic ligand, pyromellitic acid.

    PubMed

    Barkleit, Astrid; Geipel, Gerhard; Acker, Margret; Taut, Steffen; Bernhard, Gert

    2011-01-01

    For the first time Am(III) complexation with a small organic ligand could be identified and characterized with time-resolved laser-induced fluorescence spectroscopy (TRLFS) at room temperature and trace metal concentration. With pyromellitic acid (1,2,4,5-benzene-tetracarboxylic acid, BTC) as ligand spectroscopic characteristics for the Am-BTC complex system were determined at pH 5.0, an ionic strength of 0.1 M (NaClO4) and room temperature. The fluorescence lifetimes were determined to be 23.2±2.2 ns for Am3+(aq) and 27.2±1.2 ns for the Am-BTC 1:1 complex; the emission maximum for the 5D1-(7)F1 transition is 691 nm for both species. The complex stability constant for the Am-BTC 1:1 complex was calculated to be logβ110=5.42±0.16. PMID:20943431

  2. Stability of rare-earth complexes with acetylacetone and methaccrylic acid in aqueous solution

    SciTech Connect

    Panyushkin, V.T.; Akhrimenko, N.V.

    1995-09-01

    The stability constants for lanthanide (Ln) complexes with methacrylic acid (HL) (log{beta}{sub LnL}{sup Ln}), acetylacetone (HAA) (log{beta}{sub Ln(AA){sub 3}}{sup Ln}), and mixed-ligand complexes (log{beta}{sub LnL(AA){sub 2}}{sup Ln}), [Ln(III)=La, Pr, Nd, Sm, Eu, Gd, Tb, Ho, Er, Yb, Lu] in aqueous solution are determined by potentiometric titration at 25{degrees}C and {mu}=0.1 (KCl). A nonmonotonous change in the stability constants with an increase in the atomic number number of the rare-earth metal is found to occur.

  3. Selective two-step titration of thorium by sulfate displacement of the diethylenetriaminepentaacetic acid complex

    SciTech Connect

    Kiefer, P.

    1980-07-01

    Thorium and other metals are complexed with excess diethylenetriaminepentaacetic acid (DTPA) at pH 1.4, the excess DTPA is titrated with Bi(III) to a xylenol orange end point, sulfate is added to complex Th(IV), and the displaced DTPA again is titrated with Bi(III). Of 61 metal ions and nonmetal anions tested, only Ga(III), Sc(III), tungstate, citrate, oxalate, and thiosulfate interfere seriously. Lesser interferences are In(III), Zr(IV), V(IV), and permanganate. The standard deviation is 2 ..mu..g for 56 to 840 ..mu..g Th.

  4. 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.

  5. Metal ion-humic acid nanoparticle interactions: role of both complexation and condensation mechanisms.

    PubMed

    Town, Raewyn M; van Leeuwen, Herman P

    2016-07-21

    Purely Donnan type models for electrostatic binding by humic acid (HA) nanoparticles are shown to be physically incomplete. To describe the extent of ion binding by HA, such models need to invoke parameters that are not consistent with experimental observations. These disparate parameters include anomalously high Donnan potentials, as well as intrinsic affinity constants for electrostatically associating ions such as Ca(2+). In contrast, the recently introduced counterion condensation - Donnan model (CCD) provides a physicochemically realistic description of the electrostatic contribution to metal ion binding by humic acid nanoparticles. The extent of Ca(2+)-HA association can be adequately described solely in terms of electrostatics only, including counterion condensation in the intraparticulate double layer in addition to Donnan partitioning in the remainder of the particle body. The binding of Cd(ii), Pb, (ii) and Cu(ii) by HA also involves inner-sphere complex formation leading to intraparticulate metal species distributions with major proportions of condensed and complexed ions. PMID:27327433

  6. Local Solvent Acidities in β-Cyclodextrin Complexes with PRODAN Derivatives

    PubMed Central

    Naughton, Hannah R.; Abelt, Christopher J.

    2013-01-01

    The local solvent acidities (SA scale) of six 6-carbonyl-2-aminonaphthalene derivatives as β-cyclodextrin complexes in water are determined through fluorescence quenching. The local polarities (ETN scale) are determined through the shift of the emission center-of-mass. The apparent SA values reflect the solvent structure surrounding the guest’s carbonyl group, whereas the apparent ETN values reveal the net polarity of the entire guest molecule. Comparison of these values affords greater insight into the structures of the host-guest complexes. Derivatives 1 and 5 show unusually large acidities indicative of highly exposed carbonyl groups. The remaining compounds give emission intensities pointing to shielded carbonyl groups. In this study PRODAN and its derivatives are functioning as dual channel sensors of their local environment. PMID:23473052

  7. 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

  8. Transient pseudothrombocytopenia in a neonate: transmission of a maternal EDTA-dependent anticoagulant.

    PubMed

    Ohno, Norioki; Kobayashi, Masao; Hayakawa, Seiichi; Utsunomiya, Akari; Karakawa, Shuhei

    2012-01-01

    EDTA-dependent pseudothrombocytopenia (PTCP) is characterised by a low platelet count caused by autoantibodies in the serum reacting with EDTA-anticoagulated blood. EDTA-dependent PTCP is caused by a factor that retains EDTA anticoagulation activity in the serum. We report here that a neonate from a mother with PTCP presented with transient low platelet counts when EDTA was used as an anticoagulant. To confirm the transmission of a maternal serum factor to the neonate, we examined to add the maternal serum into the normal blood. Platelet count decreased significantly after adding maternal serum. Clumped platelets were also observed in the smears of mixed samples. PMID:21988316

  9. 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

  10. Studying Arsenite-Humic Acid Complexation Using Size Exclusion Chromatography-Inductively Coupled Plasma Mass Spectrometry

    PubMed Central

    Liu, Guangliang; Cai, Yong

    2012-01-01

    Arsenic (As) can form complexes with dissolved organic matter (DOM), which affects the fate of arsenic in waste sites and natural environments. It remains a challenge to analyze DOM-bound As, in particular by using a direct chromatographic separation method. Size exclusion chromatography (SEC) hyphenated with UV spectrophotometer and inductively coupled plasma mass spectrometry (ICP-MS) was developed to characterize the complexation of arsenite (AsIII) with DOM. This SEC-UV-ICP-MS method is able to differentiate AsIII-DOM complexes from free As species and has the advantage of direct determination of both free and DOM-bound AsIII through mild separation. The suitability of this method for studying AsIII-DOM complexation was demonstrated by its application, in combination with the Scatchard plot and nonlinear regression of ligand binding model, for characterizing AsIII complexation with humic acid (HA) in the absence or presence of natural sand. The results suggest that, consistent with polyelectrolytic nature of HA, the AsIII-HA complexation should be accounted for by multiple classes of binding sites. By loosely classifying the binding sites into strong (S1) and weak (S2) sites, the apparent stability constants (Ks) of the resulting As-DOM complexes were calculated as log Ks1 = 6.5–7.1 while log Ks2 = 4.7–5.0. PMID:22664255

  11. 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 intramolecular PT barrier from ~45 kcal mol(-1) in anhydrous complex to ~11.5 kcal mol(-1) in trihydrated clusters. While, the hydration effects on intermolecular PT barrier is slight. The relative stability of MC varies slightly by hydration due to the strong hydrogen bond interaction between melamine and cyanuric acid fragments. Graphical Abstract Hydration effect on proton transfer in melamine-cyanuric acid complex. PMID:27351422

  12. 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

  13. Design and evaluation of Lumefantrine – Oleic acid self nanoemulsifying ionic complex for enhanced dissolution

    PubMed Central

    2013-01-01

    Background Lumefantrine, an antimalarial molecule has very low and variable bioavailability owing to its extremely poor solubility in water. It is recommended to be taken with milk to enhance its solubility and bioavailability. The aim of present study was to develop a Self Nanoemulsifying Delivery system (SNEDs) of lumefantrine (LF) to achieve rapid and complete dissolution independent of food-fat and surfactant in dissolution media. Methods Solubility of LF in oil, co-solvent/co-surfactant and surfactant solution and emulsification efficiency of surfactant were analyzed to optimize the LF loaded self nanoemulsifying preconcentrate. Effect of LF-oleic acid complexation on emulsification, droplet size, zeta potential and dissolution were investigated. Effect of milk concentration and fat content on saturation solubility and dissolution of LF was investigated. Dissolution of marketed formulation and LF-SNEDs was carried out in pH 1.2 and pH 6.8 phosphate buffer. Results LF exhibited very high solubility in oleic acid owing to complexation between tertiary amine of LF and carboxyl group of oleic acid (OA). Cremophore EL and medium chain monoglyceride were selected surfactant and co-surfactant, respectively. Significantly smaller droplet size (37 nm), shift in zeta potential from negative to positive value, very high drug loading in lipid based system (> 10%), no precipitation after dissolution are the major distinguish characteristics contributed by LF-OA complex in the SNED system. Saturation solubility and dissolution study in milk containing media pointed the significant increment in solubility of LF in the presence of milk-food fat. LF-SNEDs showed > 90% LF release within 30 min in pH 1.2 while marketed tablet showed almost 0% drug release. Conclusion Self nanoemulsification promoting ionic complexation between basic drug and oleic acid hold great promise in enhancing solubility of hydrophobic drugs. PMID:23531442

  14. Phosphine and thiophene cyclopalladated complexes: hydrolysis reactions in strong acidic media.

    PubMed

    García, Begoña; Hoyuelos, Francisco J; Ibeas, Saturnino; Muñoz, María S; Navarro, Ana M; Peñacoba, Indalecio A; Leal, José M

    2010-12-01

    The mechanisms for the hydrolysis of organopalladium complexes [Pd(CNN)R]BF(4) (R=P(OPh)(3), PPh(3), and SC(4)H(8)) were investigated at 25 °C by using UV/Vis absorbance measurements in 10 % v/v ethanol/water mixtures containing different sulphuric acid concentrations in the 1.3-11.7 M range. In all cases, a biphasic behavior was observed with rate constants k(1obs), which corresponds to the initial step of the hydrolysis reaction, and k(2obs), where k(1obs)>k(2obs). The plots of k(1obs) and k(2obs) versus sulfuric acid concentration suggest a change in the reaction mechanism. The change with respect to the k(1obs) value corresponds to 35 %, 2 %, and 99 % of the protonated complexes for R=PPh(3), P(OPh)(3), and SC(4)H(8), respectively. Regarding k(2obs), the change occurred in all cases at about 6.5 M H(2)SO(4) and matched up with the results reported for the hydrolysis of the 2-acetylpyridinephenylhydrazone (CNN) ligand. By using the excess acidity method, the mechanisms were elucidated by carefully looking at the variation of k(i),(obs) (i=1,2) versus cH+. The rate-determining constants, k(0,A-1), k(0,A-2), and k(0,A-SE2) were evaluated in all cases. The R=P(OPh)(3) complex was most reactive due to its π-acid character, which favors the rupture of the trans nitrogen-palladium bond in the A-2 mechanism and also that of the pyridine nitrogen-palladium bond in the A-1 mechanism. The organometallic bond exerts no effect on the relative basicity of the complexes, which are strongly reliant on the substituent. PMID:21125574

  15. Novel one-pot synthesis of dicarboxylic acids mediated alginate-zirconium biopolymeric complex for defluoridation of water.

    PubMed

    Prabhu, Subbaiah Muthu; Meenakshi, Sankaran

    2015-04-20

    The present investigation explains the fluoride removal from aqueous solution using alginate-zirconium complex prepared with respective dicarboxylic acids like oxalic acid (Ox), malonic acid (MA) and succinic acid (SA) as a medium. The complexes viz., alginate-oxalic acid-zirconium (Alg-Ox-Zr), alginate-malonic acid-zirconium (Alg-MA-Zr) and alginate-succinic acid-zirconium (Alg-SA-Zr) were synthesized and studied for fluoride removal. The synthesized complexes were characterized by FTIR, XRD, SEM with EDAX and mapping images. The effects of various operating parameters were optimized. The result showed that the maximum removal of fluoride 9653mgF(-)/kg was achieved by Alg-Ox-Zr complex at acidic pH in an ambient atmospheric condition. Equilibrium data of Alg-Ox-Zr complex was fitted well with Freundlich isotherm. The calculated values of thermodynamic parameters indicated that the fluoride adsorption is spontaneous and endothermic in nature. The mechanism of fluoride removal behind Alg-Ox-Zr complex has been proposed in detail. The suitability of the Alg-Ox-Zr complex has been tested with the field sample collected in a nearby fluoride endemic area. PMID:25662688

  16. Tandem Catalytic Depolymerization of Lignin by Water-Tolerant Lewis Acids and Rhodium Complexes.

    PubMed

    Jastrzebski, Robin; Constant, Sandra; Lancefield, Christopher S; Westwood, Nicholas J; Weckhuysen, Bert M; Bruijnincx, Pieter C A

    2016-08-23

    Lignin is an attractive renewable feedstock for aromatic bulk and fine chemicals production, provided that suitable depolymerization procedures are developed. Here, we describe a tandem catalysis strategy for ether linkage cleavage within lignin, involving ether hydrolysis by water-tolerant Lewis acids followed by aldehyde decarbonylation by a Rh complex. In situ decarbonylation of the reactive aldehydes limits loss of monomers by recondensation, a major issue in acid-catalyzed lignin depolymerization. Rate of hydrolysis and decarbonylation were matched using lignin model compounds, allowing the method to be successfully applied to softwood, hardwood, and herbaceous dioxasolv lignins, as well as poplar sawdust, to give the anticipated decarbonylation products and, rather surprisingly, 4-(1-propenyl)phenols. Promisingly, product selectivity can be tuned by variation of the Lewis-acid strength and lignin source. PMID:27440544

  17. Preparation of Monodisperse Iron Oxide Nanoparticles via the Synthesis and Decomposition of Iron Fatty Acid Complexes

    PubMed Central

    2009-01-01

    Iron fatty acid complexes (IFACs) are prepared via the dissolution of porous hematite powder in hot unsaturated fatty acid. The IFACs are then decomposed in five different organic solvents under reflux conditions in the presence of the respective fatty acid. The XRD analysis results indicate that the resulting NPs comprise a mixture of wustite, magnetite, and maghemite phases. The solvents with a higher boiling point prompt the formation of larger NPs containing wustite as the major component, while those with a lower boiling point produce smaller NPs with maghemite as the major component. In addition, it is shown that unstable NPs with a mixed wustite–magnetite composition can be oxidized to pure maghemite by extending the reaction time or using an oxidizing agent. PMID:20628451

  18. Metallo-hydrazone complexes immobilized in zeolite Y: Synthesis, identification and acid violet-1 degradation

    NASA Astrophysics Data System (ADS)

    Ahmed, Ayman H.; Thabet, M. S.

    2011-12-01

    Copper(II), cobalt(II) and nickel(II) complexes of hydrazone ligand (SAPH) derived from salicylaldehyde and phenylhydrazine have been encapsulated in zeolite-Y super cages via ship-in-a-bottle synthesis. Detailed characterization of the intrazeolitic complexes were performed by elemental analysis, spectral (FT-IR, UV-Vis.) studies, magnetic measurements and X-ray diffraction. Furthers, surface texture and thermal analysis (TG, DTG, DTA) have provided further evidence for successful immobilization of the metal complexes inside zeolite Y. Investigation of the stereochemistry of these incorporated chelates pointed out that, SAPH ligand is capable to coordinate with the central metal through the (C dbnd N), phenolic (OH) and (NH) groups forming polynuclear structures. The involvement of zeolite oxygen in coordination was postulated in the hybrid materials. The intrazeolitic copper, cobalt and nickel-SAPH complexes have distorted tetrahedral, octahedral and square-pyramidal configurations, respectively. The zeolite encapsulated complexes are thermally stable up to 800 °C except Cu(II) sample which is thermally stable up to midpoint 428 °C. The assessment of the catalytic activity was performed by the use of the photo-degradation of acid violet-1 dye as a probe reaction in presence of H 2O 2 as an oxidant. Decolorization of acid violet-1 dye was examined under the same conditions whereas the unpromoted zeolite and Cu II, Co II, Ni II-hydrazone complexes supported on zeolite showed 13% and 76%, 53%, 43% color removal, respectively. The results revealed that, the zeolite encapsulated Cu(II) complex generally exhibited better catalytic efficiency (76%) compared with other investigated zeolite encapsulated metal-hydrazone samples.

  19. Signs of antimetastatic activity of palladium complexes of methylenediphosphonic acid in IR spectra

    NASA Astrophysics Data System (ADS)

    Tolstorozhev, G. B.; Skornyakov, I. V.; Pekhnio, V. I.; Kozachkova, A. N.; Sharykina, N. I.

    2012-07-01

    We have used Fourier transform IR spectroscopy methods to study normal mouse lung tissue and also after subcutaneous transplantation of a B-16 melanoma tumor in the tissue. We also studied tissues with B-16 melanoma after they were treated with coordination compounds based on palladium complexes of methylenediphosphonic acid. The IR spectra of the lung tissues with metastases in the region of the C = O stretching vibrations are different from the IR spectra of normal tissue. We identified spectroscopic signs of the presence of metastases in the lung. We show that when a cancerous tumor is treated with a preparation of palladium complexes of methylenediphosphonic acid, the spectroscopic signs of the presence of metastases in the lung are missing. After treatment with the optimal dose of this drug, the IR spectrum of the lung tissue in which multiple metastases were present before treatment corresponds to the spectrum of normal tissue. We have determined the efficacy of the antitumor activity of coordination compounds based on palladium complexes of methylenediphosphonic acid.

  20. Luminescence behavior of terbium sulphosalicylic acid complexes in sol-gel derived host materials

    SciTech Connect

    Fan, X.; Wang, M.; Wang, Z.; Hong, Z.

    1997-08-01

    The formation and luminescence behavior of terbium sulphosalicylic acid (TbSSA) complexes in sol-gel derived host materials have been investigated. The 5-sulphosalicylic acid (H{sub 3}SSA) was dissolved in ethanol in advance, and then the TbCl{sub 3} and ethanol containing H{sub 3}SSA were introduced into the initial precursor sol, respectively. The resulting sol exhibits intramolecular energy transfer from the coordinated sulphosalicylic acid to the terbium ion. The TbSSA complex has formed in the TbCl{sub 3} and H{sub 3}SSA codoped sol. The complexes were found to have notably higher fluorescence intensities than TbCl{sub 3} in both the sol and the gel. In the sol, the concentration quenching was a diffusion-controlled process due to aggregation and effective collision between molecules and the fluorescence was decreased with increase of H{sub 3}SSA concentration. On the other hand, the molecules in the gel were isolated in the pores of the silica network. The fluorescence intensities of TbSSA in the gel were increased with the increase of concentration ratio of H{sub 3}SSA/TbCl{sub 3}. Maximum fluorescence intensity was obtained at H{sub 3}SSA/TbCl{sub 3} = 2.

  1. Cationic liposome–nucleic acid complexes for gene delivery and gene silencing

    PubMed Central

    Ewert, Kai K.; Majzoub, Ramsey N.; Leal, Cecília

    2014-01-01

    Cationic liposomes (CLs) are studied worldwide as carriers of DNA and short interfering RNA (siRNA) for gene delivery and gene silencing, and related clinical trials are ongoing. Optimization of transfection efficiency and silencing efficiency by cationic liposome carriers requires a comprehensive understanding of the structures of CL–nucleic acid complexes and the nature of their interactions with cell membranes as well as events leading to release of active nucleic acids within the cytoplasm. Synchrotron x-ray scattering has revealed that CL–nucleic acid complexes spontaneously assemble into distinct liquid crystalline phases including the lamellar, inverse hexagonal, hexagonal, and gyroid cubic phases, and fluorescence microscopy has revealed CL–DNA pathways and interactions with cells. The combining of custom synthesis with characterization techniques and gene expression and silencing assays has begun to unveil structure–function relations in vitro. As a recent example, this review will briefly describe experiments with surface-functionalized PEGylated CL–DNA nanoparticles. The functionalization, which is achieved through custom synthesis, is intended to address and overcome cell targeting and endosomal escape barriers to nucleic acid delivery faced by PEGylated nanoparticles designed for in vivo applications. PMID:25587216

  2. 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. PMID:27497532

  3. EDTA-dependent pseudothrombocytopenia confirmed by supplementation of kanamycin; a case report.

    PubMed

    Ahn, Hae Lyun; Jo, Young Il; Choi, Young Suk; Lee, Jung Yeon; Lee, Hae Woon; Kim, Seong Ryul; Sim, Joon; Lee, Weon; Jin, Chun Jo

    2002-03-01

    EDTA-dependent pseudothrombocytopenia (PTCP) is the phenomenon of a spurious low platelet count due to EDTA-induced aggregation of platelets. Since the failure to recognize EDTA-dependent PTCP may result in incorrect diagnosis and inappropriate treatment, the recognition of this phenomenon is very important. We report an insidious case of EDTA-dependent PTCP confirmed by supplementation of kanamycin to anticoagulant in a 53-year-old women. Although sodium citrate and heparin usually prevented the aggregation of platelets in EDTA-dependent PTCP patients, these anticoagulants failed in preventing PTCP in our case. EDTA-dependent PTCP was confirmed by the findings that the clumping of platelets on microscopic evaluation was found in EDTA-anticoagulated blood samples, whereas thrombocytopenia and platelet aggregation were not revealed in the sample supplemented with kanamycin. PMID:12014216

  4. EDTA-dependent Pseudothrombocytopenia Confirmed by Supplementation of Kanamycin; A Case Report

    PubMed Central

    Ahn, Hae Lyun; Jo, Young; Choi, Young Suk; Lee, Jung Yeon; Lee, Hae Woon; Kim, Seong Ryul; Sim, Joon; Lee, Weon; Jin, Chun Jo

    2002-01-01

    EDTA-dependent pseudothrombocytopenia (PTCP) is the phenomenon of a spurious low platelet count due to EDTA-induced aggregation of platelets. Since the failure to recognize EDTA-dependent PTCP may result in incorrect diagnosis and inappropriate treatment, the recognition of this phenomenon is very important. We report an insidious case of EDTA-dependent PTCP confirmed by supplementation of kanamycin to anticoagulant in a 53-year-old women. Although sodium citrate and heparin usually prevented the aggregation of platelets in EDTA-dependent PTCP patients, these anticoagulants failed in preventing PTCP in our case. EDTA-dependent PTCP was confirmed by the findings that the dumping of platelets on microscopic evaluation was found in EDTA-anticoagulated blood samples, whereas thrombocytopenia and platelet aggregation were not revealed in the sample supplemented with kanamycin. PMID:12014216

  5. EDTA-dependent pseudothrombocytopenia: a clinical study of 18 patients and a review of the literature.

    PubMed

    Berkman, N; Michaeli, Y; Or, R; Eldor, A

    1991-03-01

    EDTA-dependent pseudothrombocytopenia (EDTA-PTCP) is the phenomenon of a spurious low platelet count due to the appearance of antibodies that cause platelet agglutination in blood anticoagulated with EDTA. We review here the clinical features of 18 patients with EDTA-PTCP treated in our hospital from 1984 to 1987 as well as those of 34 patients reported in the literature. This phenomenon appears more frequently in severely ill patients, in association with autoimmune, neoplastic, atherosclerosis-related, and liver diseases. In the majority of our patients, EDTA-PTCP appeared during hospitalization, indicating that the antibody is an acquired one. Neither splenomegaly nor the presence of autoimmune markers were features of this entity. Unlike true thrombocytopenias, EDTA-PTCP is associated with a normal mean platelet volume. Awareness of this entity is essential since EDTA-PTCP is frequently misdiagnosed and therefore incorrectly treated. PMID:1899964

  6. [sup 90]Y-labeled antibody uptake by human tumor xenografts and the effect of systemic administration of EDTA

    SciTech Connect

    Rowlinson-Busza, G.; Snook, D.; Epenetos, A.A. )

    1994-03-30

    A human tumor xenograft model was used to compare the tumor and normal tissue uptake of a tumor-associated monoclonal antibody radiolabeled with [sup 125]I or [sup 90]Y. Nude mice bearing SC xenografts of the human colon adenocarcinoma, HT29, were injected with a mixture of [sup 125]I- and [sup 90]Y-DTPA-labeled AUA1 monoclonal antibody, which recognizes an antigen expressed on the surface of the tumor cells. In addition, the effect of systemic ethylenediaminetetraacetic acid (EDTA) administration on [sup 90]Y-labeled antibody clearance, tumor uptake of antibody and bone accumulation of [sup 90]Y was studied in a nude mouse model of intraperitoneal cancer. Both the absolute amount (%id[center dot]g[sup -1]) and the tumor:normal tissue ratios were superior for the [sup 90]Y-labeled antibody, compared with the iodinated antibody, with the notable exception of bone. These results suggest that [sup 90]Y is a preferable isotope to iodine for radioimmunotherapy of solid masses, but that myelotoxicity due to bone uptake of released [sup 90]Y will limit the radiation dose which can be given when DTPA is used to chelate the [sup 90]Y. The [sup 90]Y-labeled antibody showed similar serum stability in vitro in the presence or absence of EDTA after incubation for up to 48 h. In vivo, urine excretion of [sup 90]Y was significantly enhanced in mice receiving daily injections of 20 mg EDTA for 3 days, commencing 2 h after intraperitoneal antibody administration, compared with control mice. There was no significant difference in the tumor uptake of [sup 90]Y-labeled antibody in EDTA-treated and control mice at any time-point up to 9 days postinjection. However, the bone levels of [sup 90]Y were significantly reduced in EDTA-treated mice at all times from 1 to 9 days. Based on these results, it should be possible to increase the amount of [sup 90]Y-labeled antibody administered, by chelating the released [sup 90]Y with systemic EDTA to facilitate its excretion. 50 refs., 5 figs.

  7. Desorption of copper and cadmium from soils enhanced by organic acids.

    PubMed

    Yuan, Songhu; Xi, Zhimin; Jiang, Yi; Wan, Jinzhong; Wu, Chan; Zheng, Zhonghua; Lu, Xiaohua

    2007-07-01

    The adsorption/desorption behavior of copper and cadmium on soils was investigated in this study. The adsorption isotherm of copper and cadmium conformed to Langmuir equation better than Freundlich equation. The effect of ionic strength, pH, and organic acid, including ethylenediamine tetraacetic disodium acid salt (EDTA), citric acid, oxalic acid and tartaric acid, on the desorption of copper and cadmium was studied. The desorption of copper and cadmium increased with the increase of ionic strength, while the desorption decreased with the rise of pH. The desorption of copper and cadmium enhanced by organic acids was influenced by pH. EDTA showed excellent enhancement on the desorption of both copper and cadmium; citric acid demonstrated great enhancement on the desorption of copper but negligible enhancement on the desorption of cadmium; oxalic acid enhanced the desorption of copper only at pH around 6.4 and enhanced the desorption of cadmium in the pH range from 6.4 to 10.7; tartaric acid slightly enhanced the desorption of copper but negligibly enhanced the desorption of cadmium. The desorption mechanism in the presence of organic acids were explained as the competition of complexation, adsorption and precipitation. The net effect determined the desorption efficiency. This study provided guidance for the selection of organic acids to enhance the electrokinetic (EK) remediation of copper and cadmium from contaminated soils. PMID:17349675

  8. Oleic Acid Stimulates Complete Oxidation of Fatty Acids through Protein Kinase A-dependent Activation of SIRT1-PGC1α Complex*

    PubMed Central

    Lim, Ji-Hong; Gerhart-Hines, Zachary; Dominy, John E.; Lee, Yoonjin; Kim, Sungjin; Tabata, Mitsuhisa; Xiang, Yang K.; Puigserver, Pere

    2013-01-01

    Fatty acids are essential components of the dynamic lipid metabolism in cells. Fatty acids can also signal to intracellular pathways to trigger a broad range of cellular responses. Oleic acid is an abundant monounsaturated omega-9 fatty acid that impinges on different biological processes, but the mechanisms of action are not completely understood. Here, we report that oleic acid stimulates the cAMP/protein kinase A pathway and activates the SIRT1-PGC1α transcriptional complex to modulate rates of fatty acid oxidation. In skeletal muscle cells, oleic acid treatment increased intracellular levels of cyclic adenosine monophosphate (cAMP) that turned on protein kinase A activity. This resulted in SIRT1 phosphorylation at Ser-434 and elevation of its catalytic deacetylase activity. A direct SIRT1 substrate is the transcriptional coactivator peroxisome proliferator-activated receptor γ coactivator 1-α (PGC1α), which became deacetylated and hyperactive after oleic acid treatment. Importantly, oleic acid, but not other long chain fatty acids such as palmitate, increased the expression of genes linked to fatty acid oxidation pathway in a SIRT1-PGC1α-dependent mechanism. As a result, oleic acid potently accelerated rates of complete fatty acid oxidation in skeletal muscle cells. These results illustrate how a single long chain fatty acid specifically controls lipid oxidation through a signaling/transcriptional pathway. Pharmacological manipulation of this lipid signaling pathway might provide therapeutic possibilities to treat metabolic diseases associated with lipid dysregulation. PMID:23329830

  9. 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.

  10. Crystal structures of complexes of vitamin D receptor ligand-binding domain with lithocholic acid derivatives

    PubMed Central

    Masuno, Hiroyuki; Ikura, Teikichi; Morizono, Daisuke; Orita, Isamu; Yamada, Sachiko; Shimizu, Masato; Ito, Nobutoshi

    2013-01-01

    The secondary bile acid lithocholic acid (LCA) and its derivatives act as selective modulators of the vitamin D receptor (VDR), although their structures fundamentally differ from that of the natural hormone 1α,25-dihydroxyvitamin D3 [1,25(OH)2D3)]. Here, we have determined the crystal structures of the ligand-binding domain of rat VDR (VDR-LBD) in ternary complexes with a synthetic partial peptide of the coactivator MED1 (mediator of RNA polymerase II transcription subunit 1) and four ligands, LCA, 3-keto LCA, LCA acetate, and LCA propionate, with the goal of elucidating their agonistic mechanism. LCA and its derivatives bind to the same ligand-binding pocket (LBP) of VDR-LBD that 1,25(OH)2D3 binds to, but in the opposite orientation; their A-ring is positioned at the top of the LBP, whereas their acyclic tail is located at the bottom of the LBP. However, most of the hydrophobic and hydrophilic interactions observed in the complex with 1,25(OH)2D3 are reproduced in the complexes with LCA and its derivatives. Additional interactions between VDR-LBD and the C-3 substituents of the A-ring are also observed in the complexes with LCA and its derivatives. These may result in the observed difference in the potency among the LCA-type ligands. PMID:23723390

  11. A study of the metal binding capacity of saccharinic acids formed during the alkali catalysed decomposition of cellulosic materials: nickel complexation by glucoisosaccharinic acids and xyloisosaccharinic acids.

    PubMed

    Almond, Michael; Belton, Daniel; Humphreys, Paul N; Laws, Andrew P

    2016-06-01

    The stoichiometry of the metal complexes formed between nickel and the ligand β-glucoisosaccharinic acid (β-GISA) and a racemic mixture of enantiomers of xyloisosaccharinic acid (XISA) has been determined at both neutral and alkaline pHs. Bjerrum plots, Job's plots and conductance measurements indicated that for each of the systems one to one Ni(ligand) complexes were formed at near neutral pHs (<7.5). At intermediate alkaline pHs (7.5-13) there is evidence to support the formation and precipitation of Ni2(ligand)(OH)3 complexes, finally, at high pH (>13) sparingly soluble Ni2(ligand)(OH)4 complexes were formed. The stability constants for the Ni(β-GISA), Ni(α-GISA) and Ni(XISA) complexes formed at neutral pH were determined under identical conditions using polarographic studies. The measured stability constants for Ni(β-GISA) (log10 β = 1.94 ± 0.15) and for Ni(α-GISA)(log10 β = 2.07 ± 0.13) are very similar; the value measured for the Ni(XISA) complex (log10 β = 0.83) was an order of magnitude smaller. The stability constants for the Ni2(Ligand)(OH)4 complexes formed at highly alkaline pHs were determined using the Schubert method. The measured stability constant for Ni2(β-GISA)(OH)4 (log10 β = 30.6 ± 0.5) was an order of magnitude bigger than the value for Ni2(α-GISA)(OH)4 (log10 β = 29.0 ± 0.5) measured under identical conditions. Attempts to measure the stability constant for Ni2(XISA)(OH)4 were unsuccessful; Ni2(XISA)(OH)4 complexes were not present in significant amounts at high pH to allow the log10β value to be determined by the Schubert method. PMID:27107221

  12. Adverse effects in 5 patients receiving EDTA at an outpatient chelation clinic.

    PubMed

    Morgan, Brent W; Kori, Singleton; Thomas, Jerry D

    2002-10-01

    Despite limited scientific evidence, Na2EDTA chelation therapy has been advocated for a variety of conditions including atherosclerosis. Five patients presented with symptoms that developed 30 min-2 h into chelation therapy at an outpatient clinic with infusions of sterile waterwith 3 g Na2EDTA, 2 g MgCl, 100 mg B12, 100 mg B6, 1 ml bit B complex and 15 g Vit C; 1 patient also received 10 ml of 50% DMSO iv. All patients experienced gastrointestinal and musculoskeletal symptoms. Additional effects were (4/5), excessive thirst (4/5), and diaphoresis (4/5). On presentation patients were hypotensive (5/5), tachycardic (4/5) and febrile (5/5). Therapy included iv. fluids (5/5), dopamine (1/5), and ivantibiotics (4/5). Initial data showed leukopenia (5/5), thrombocytopenia (3/5), bandemia (4/5), EKG abnormalities of unknown acuity (5/5), and transient, mild rise in serum creatinine (3/4). All patients were discharged without permanent sequelae. It is unclear if effects were related to dose or rate of administration. PMID:12361109

  13. Characterization and dynamic properties for the solid inclusion complexes of β-cyclodextrin and perfluorooctanoic acid.

    PubMed

    Karoyo, Abdalla H; Sidhu, Paul; Wilson, Lee D; Hazendonk, Paul

    2013-07-11

    The structural characterization and dynamic properties of solid-state inclusion complexes (ICs) formed between β-cyclodextrin (β-CD; host) and perfluorooctanoic acid (PFOA; guest) were investigated using (13)C NMR spectroscopy. The 1:1 and 2:1 host/guest solid-state complexes were prepared using a modified dissolution method to obtain complexes with high phase purity. These complexes were further characterized using differential scanning calorimetry (DSC), FT-IR spectroscopy, powder X-ray diffraction (PXRD), (19)F directpolarization (DP), and (13)C cross-polarization (CP) with magic-angle spinning (MAS) NMR spectroscopy. The (19)F → (13)C CP results provided unequivocal support for the formation of well-defined inclusion compounds. The phase purity of the complexes formed between β-CD and PFOA were assessed using the (19)F DP NMR technique at variable temperature (VT) and MAS at 20 kHz. The complexes were found to be of high phase purity when prepared in accordance with the modified dissolution method. The motional dynamics of the guest in the solid complexes were assessed using T1/T2/T1ρ relaxation NMR methods at ambient and VT conditions. The relaxation data revealed reliable and variable guest dynamics for the 1:1 versus 2:1 complexes at the VTs investigated. The motional dynamics of the guest molecules involve an ensemble of axial motions of the whole chain and 120° rotational jumps of the methyl (CF3) group at the termini of the perfluorocarbon chain. The axial and rotational dynamics of the guest in the 1:1 and 2:1 complexes differ in distribution and magnitude in accordance with the binding geometry of the guest within the host. PMID:23713518

  14. Electron transfer reactions of osmium(II) complexes with phenols and phenolic acids

    NASA Astrophysics Data System (ADS)

    Rajeswari, Angusamy; Ramdass, Arumugam; Muthu Mareeswaran, Paulpandian; Velayudham, Murugesan; Rajagopal, Seenivasan

    2016-07-01

    Three [Os(NN)3]2+ complexes (NN = polypyridine) with ligands of varying hydrophobicity were synthesized and characterized by NMR spectral techniques. The geometry of the molecules are optimized by DFT calculations. The interaction between [Os(NN)3]2+ complexes and phenolate ion in ground state is confirmed by absorption spectral study and the binding constant values are in the range of 3-740 M-1. The photoinduced electron transfer reaction of these [Os(NN)3]2+ complexes with phenols and phenolic acids at pH 12.5 leads to the formation of phenoxyl radical confirmed through transient absorption spectral study. Binding constants and electron transfer rate constants within the [Os(NN)3]2+-phenolate ion adduct account for the change for the overall quenching constant with the change of structure of reactants.

  15. 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

  16. Influence of Humic Acid Complexation with Metal Ions on Extracellular Electron Transfer Activity.

    PubMed

    Zhou, Shungui; Chen, Shanshan; Yuan, Yong; Lu, Qin

    2015-01-01

    Humic acids (HAs) can act as electron shuttles and mediate biogeochemical cycles, thereby influencing the transformation of nutrients and environmental pollutants. HAs commonly complex with metals in the environment, but few studies have focused on how these metals affect the roles of HAs in extracellular electron transfer (EET). In this study, HA-metal (HA-M) complexes (HA-Fe, HA-Cu, and HA-Al) were prepared and characterized. The electron shuttle capacities of HA-M complexes were experimentally evaluated through microbial Fe(III) reduction, biocurrent generation, and microbial azoreduction. The results show that the electron shuttle capacities of HAs were enhanced after complexation with Fe but were weakened when using Cu or Al. Density functional theory calculations were performed to explore the structural geometry of the HA-M complexes and revealed the best binding sites of the HAs to metals and the varied charge transfer rate constants (k). The EET activity of the HA-M complexes were in the order HA-Fe > HA-Cu > HA-Al. These findings have important implications for biogeochemical redox processes given the ubiquitous nature of both HAs and various metals in the environment. PMID:26593782

  17. Influence of Humic Acid Complexation with Metal Ions on Extracellular Electron Transfer Activity

    PubMed Central

    Zhou, Shungui; Chen, Shanshan; Yuan, Yong; Lu, Qin

    2015-01-01

    Humic acids (HAs) can act as electron shuttles and mediate biogeochemical cycles, thereby influencing the transformation of nutrients and environmental pollutants. HAs commonly complex with metals in the environment, but few studies have focused on how these metals affect the roles of HAs in extracellular electron transfer (EET). In this study, HA-metal (HA-M) complexes (HA-Fe, HA-Cu, and HA-Al) were prepared and characterized. The electron shuttle capacities of HA-M complexes were experimentally evaluated through microbial Fe(III) reduction, biocurrent generation, and microbial azoreduction. The results show that the electron shuttle capacities of HAs were enhanced after complexation with Fe but were weakened when using Cu or Al. Density functional theory calculations were performed to explore the structural geometry of the HA-M complexes and revealed the best binding sites of the HAs to metals and the varied charge transfer rate constants (k). The EET activity of the HA-M complexes were in the order HA-Fe > HA-Cu > HA-Al. These findings have important implications for biogeochemical redox processes given the ubiquitous nature of both HAs and various metals in the environment. PMID:26593782

  18. DNA binding mode of novel tetradentate amino acid based 2-hydroxybenzylidene-4-aminoantipyrine complexes

    NASA Astrophysics Data System (ADS)

    Raman, N.; Sobha, S.; Selvaganapathy, M.; Mahalakshmi, R.

    2012-10-01

    Few transition metal complexes of tetradentate N2O2 donor Schiff base ligands containing 2-hydroxybenzylidene-4-aminoantipyrine and amino acids (alanine/valine) abbreviated to KHL1/KHL2 have been synthesized. All the metal complexes have been fully characterized with the help of elemental analyses, molecular weights, molar conductance values, magnetic moments and spectroscopic data. The Schiff bases KHL1/KHL2 are found to act as tetradentate ligands using N2O2 donor set of atoms leading to a square-planar geometry for the complexes around the metal ions. The binding behaviors of the complexes to calf thymus DNA have been investigated by absorption spectra, viscosity measurements and cyclic voltammetry. The DNA binding constants reveal that all these complexes interact with DNA through minor groove binding mode. The studies on mechanism of photocleavage reveal that singlet oxygen (1O2) and superoxide anion radical (O2rad -) may play an important role in the photocleavage. The Schiff bases and their metal complexes have been screened for their in vitro antibacterial activities against Staphylococcus aureus, Pseudomonas aeruginosa, Escherichia coli, Staphylococcus epidermidis, Klebsiella pneumoniae and antifungal activities against Aspergillus niger, Fusarium solani, Culvularia lunata, Rhizoctonia bataicola and Candida albicans by MIC method.

  19. Influence of Humic Acid Complexation with Metal Ions on Extracellular Electron Transfer Activity

    NASA Astrophysics Data System (ADS)

    Zhou, Shungui; Chen, Shanshan; Yuan, Yong; Lu, Qin

    2015-11-01

    Humic acids (HAs) can act as electron shuttles and mediate biogeochemical cycles, thereby influencing the transformation of nutrients and environmental pollutants. HAs commonly complex with metals in the environment, but few studies have focused on how these metals affect the roles of HAs in extracellular electron transfer (EET). In this study, HA-metal (HA-M) complexes (HA-Fe, HA-Cu, and HA-Al) were prepared and characterized. The electron shuttle capacities of HA-M complexes were experimentally evaluated through microbial Fe(III) reduction, biocurrent generation, and microbial azoreduction. The results show that the electron shuttle capacities of HAs were enhanced after complexation with Fe but were weakened when using Cu or Al. Density functional theory calculations were performed to explore the structural geometry of the HA-M complexes and revealed the best binding sites of the HAs to metals and the varied charge transfer rate constants (k). The EET activity of the HA-M complexes were in the order HA-Fe > HA-Cu > HA-Al. These findings have important implications for biogeochemical redox processes given the ubiquitous nature of both HAs and various metals in the environment.

  20. Binary and ternary complexes of some inner transition metal ions with amino acids and acetyl acetone

    NASA Astrophysics Data System (ADS)

    Abu-Eittah, R. H.; Abdou, M. M.; Salem, M. B.

    1998-05-01

    The stability constants of the 1:1 and 1:2 (whenever possible) complexes formed between La3+, Ce3+, Th4+ and the amino acid anions L-alaninate, L-phenylalaninate and L-histidinate were determined by potentiometric titration in aqueous solution (25± 1 ^circC, I = 0.1 M KCl) and compared together with the constants previously determined. The various formation degree of the resulting M(L) and M(L)2 were determined. In order to relate the formation degree of M(L) and M(L)2 with the basicity of the amino acid anion (L^-), the acidity constants of the protonated amino acids, H2L^+, were also measured. The main results of this work prove that Th4+ ion forms the strongest complex with the studied amino acids. It is the only ion which forms a 1:2 complex. The heterocyclic ring of histidine plays a significant role in complexing with the studied metal ions as is clearly seen from the distribution of the degree of formation of the different complexes. The stability constants of the 1:1:1, 1:2:1 and 1:1:2 complexes formed between La3+, Ce3+, Th4+ and the anions L-alaninate, L-phenylalaninate and L-histidinate together with the acetyl acetonate ion were also determined following the same experimental set up used in the study of the simple complexes. The mixed-ligand complexes turned out to be very much stronger than the simple ligand complexes. Formation of a mixed ligand complex can be considered as a type of senergism. Les constantes de stabilité des complexes 1:1 et 2:2 (lorsque cela est possible) formés entre La3+, Ce3+, Th4+ et les anions aminoacides L-alaninate, L-phénylalaninate et L-histidinate ont été déterminées par dosage potentiométrique en solution aqueuse (25± 1 ^circC, I = 0,1 M KCl), et comparées à celles de la littérature. Les différents degrés de formation de M(L) et M(L)2 ont été quantifiés. Pour mettre en évidence la relation entre le degré de formation de M(L) et M(L)2 et la basicité des anions aminoacides (L^-), les constantes d

  1. DNA interaction with octahedral and square planar Ni(II) complexes of aspartic-acid Schiff-bases

    NASA Astrophysics Data System (ADS)

    Sallam, S. A.; Orabi, A. S.; Abbas, A. M.

    2011-12-01

    Ni(II) complexes of (S,E)-2-(2-OHbenzilydene)aspartic acid; (S,E)-2-(2,3-diOHbenzilydene)aspartic acid-; (S,E)-2-(2,4-diOH-benzilydene)aspartic acid; (S,E)-2-(2,5-diOHbenzilydene)aspartic acid and (S,E)-2-((2-OHnaphthalene-1-yl)methylene)aspartic acid Schiff-bases have been synthesized by template method in ethanol or ammonia media. They were characterized by elemental analyses, conductivity measurements, magnetic moment, UV, IR and 1H nmr spectra as well as thermal analysis (TG, DTG, DTA). The Schiff-bases are dibasic tridentate or tetradentate donors and the complexes have square planar and octahedral structures. The complexes decompose in two or three steps where kinetic and thermodynamic parameters of the decomposition steps were computed. The interactions of the formed complexes with FM-DNA were monitored by UV and fluorescence spectroscopy.

  2. Mixed-ligand complex compounds of rare-earth elements (REE) with acetylacetone and fumaric or maleic acid

    SciTech Connect

    Panyushkin, V.T.; Akhrimenko, N.V.

    1994-10-01

    Previously the authors investigated the possibility of synthesis of the f-block element mixed complexes with {beta}-diketones and organic unsaturated acids. The mixed-ligand complexes of lanthanides [Ln = Nd(III), Sm(III), Eu(III), Tb(III), Dy(III), Ho(III), and Yb(III)] with acetylacetone (acac) and fumaric or maleic acid (AcidH{sub 2}) were synthesized. The mixed-ligand complexes were prepared by the interaction of REE tris(acetylacetonates) [Ln(acac){sub 3}{center_dot} 3H{sub 2}O] with half as much excess of the organic acid in a solution of diethyl ether. According to the data of elemental analysis and thermogravimetric and spectroscopic investigations, the mixed complexes studied are of composition Ln(acac){sub 2}(AcidH){center_dot}H{sub 2}O.

  3. 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

  4. Large-volume sample stacking for analysis of ethylenediaminetetraacetic acid by capillary electrophoresis.

    PubMed

    Zhu, Zhiwei; Zhang, Lifeng; Marimuthu, Arun; Yang, Zhaoguang

    2002-09-01

    A simple, quick, and sensitive capillary electrophoretic technique-large volume stacking using the electroosmotic flow (EOF) pump (LVSEP) - has been developed for determining ethylenediaminetetraacetic acid (EDTA) in drinking water for the first time. It is based on a precapillary complexation of EDTA with Fe(III) ions, followed by large-volume sample stacking and direct UV detection at 258 nm. The curve of peak response versus concentration was linear from 5.0 to 600.0 microg/L, and 0.7 to 30.0 mg/L. The regression coefficients were 0.9988 and 0.9990, respectively. The detection limit of the current technique for EDTA analysis was 0.2 microg/L with an additional 10-fold preconcentration procedure, based on the signal-to-noise ratio of 3. As opposed to the classical capillary zone electrophoresis (CE) method, the detection limit was improved about 1000-fold by using this LVSEP method. To the best of our knowledge, it represents the highest sensitivity for EDTA analysis via CE. Several drinking water samples were tested by this novel method with satisfactory results. PMID:12207295

  5. 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

  6. 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...

  7. Potentiometric and NMR complexation studies of phenylboronic acid PBA and its aminophosphonate analog with selected catecholamines

    NASA Astrophysics Data System (ADS)

    Ptak, Tomasz; Młynarz, Piotr; Dobosz, Agnieszka; Rydzewska, Agata; Prokopowicz, Monika

    2013-05-01

    Boronic acids are a class of intensively explored compounds, which according to their specific properties have been intensively explored in last decades. Among them phenylboronic acids and their derivatives are most frequently examined as receptors for diverse carbohydrates. In turn, there is a large gap in basic research concerning complexation of catecholamines by these compounds. Therefore, we decided to undertake studies on interaction of chosen catecholamines, namely: noradrenaline (norephinephrine), dopamine, L-DOPA, DOPA-P (phosphonic analog of L-DOPA) and catechol, with simple phenyl boronic acid PBA by means of potentiometry and NMR spectroscopy. For comparison, the binding properties of recently synthesized phenylboronic receptor 1 bearing aminophosphonate function in meta-position were investigated and showed promising ability to bind catecholamines. The protonation and stability constants of PBA and receptor 1 complexes were examined by potentiometry. The obtained results demonstrated that PBA binds the catecholamines with the following affinity order: noradrenaline ⩾ dopamine ≈ L-DOPA > catechol > DOPA-P, while its modified analog 1 reveals slightly different preferences: dopamine > noradrenaline > catechol > L-DOPA > DOPA-P.

  8. ESR study of irradiated single crystals of the cocrystalline complex of cytidine: Salicylic acid

    SciTech Connect

    Close, D.M.; Sagstuen, E.

    1983-12-01

    Irradiation at 77 K of single crystals of the 1:1 complex of cytidine and salicylic acid produces a phenoxyl radical formed by oxidation of the salicylic acid. Anisotropic hyperfine coupling tensors have been determined for this radical which are associated with the para and ortho hydrogens. No cytidine oxidation products (alkoxy or hydroxyalkyl radicals) were observed at 77 K. Following the decay of the phenoxyl radical at room temperature, four radicals were detected. These include the cytosine 5--yl and 6--yl radicals, formed by H addition to the cytosine ring, and an anisotropic doublet. By UV irradiation at room temperature, it is possible to convert a significant fraction of 6-yl radicals into 5-yl radicals. Hyperfine coupling and g tensors determined for the anisotropic doublet indicate that this radical is formed in the C/sub 1'/-C/sub 2'/ region of the sugar moiety. These results indicate a shift in radiation damage away from the salicylic acid upon warming, and show that the radiation chemistry of the cocrystalline complex is different from that of the isolated bases.

  9. Intestinal peptidases form functional complexes with the neutral amino acid transporter B0AT1

    PubMed Central

    Fairweather, Stephen J.; Bröer, Angelika; O'Mara, Megan L.; Bröer, Stefan

    2012-01-01

    The brush-border membrane of the small intestine and kidney proximal tubule are the major sites for the absorption and re-absorption of nutrients in the body respectively. Transport of amino acids is mediated through the action of numerous secondary active transporters. In the mouse, neutral amino acids are transported by B0AT1 [broad neutral (0) amino acid transporter 1; SLC6A19 (solute carrier family 6 member 19)] in the intestine and by B0AT1 and B0AT3 (SLC6A18) in the kidney. Immunoprecipitation and Blue native electrophoresis of intestinal brush-border membrane proteins revealed that B0AT1 forms complexes with two peptidases, APN (aminopeptidase N/CD13) and ACE2 (angiotensin-converting enzyme 2). Physiological characterization of B0AT1 expressed together with these peptidases in Xenopus laevis oocytes revealed that APN increased the substrate affinity of the transporter up to 2.5-fold and also increased its surface expression (Vmax). Peptide competition experiments, in silico modelling and site-directed mutagenesis of APN suggest that the catalytic site of the peptidase is involved in the observed changes of B0AT1 apparent substrate affinity, possibly by increasing the local substrate concentration. These results provide evidence for the existence of B0AT1-containing digestive complexes in the brush-border membrane, interacting differentially with various peptidases, and responding to the dynamic needs of nutrient absorption in the intestine and kidney. PMID:22677001

  10. Synthesis, crystal structures, and properties of three metal complexes with N-phenylanthranilic acid

    NASA Astrophysics Data System (ADS)

    Tan, Yu-Hui; Xiong, Jian-Bo; Gao, Ji-Xing; Xu, Qing; Fu, Chao-Wu; Tang, Yun-Zhi; Yang, Shao-Ping; Wen, He-Rui

    2015-04-01

    The hydrothermal reactions between N-phenylanthranilic acid (NPA), transition metal hydroxide salts and ex-bidentate N-donor ligands in CH3CH2OH/H2O solutions afforded three new complexes, [Cd1.5(NPA)3(2,2‧-bipy)] (1), [Zn(NPA)2(2,2‧-bipy)] (2,2‧-bipy = 2,2‧-bipyridine) (2) and [Mn(NPA)2(Phen)2] (Phen = 1,10-phenanthroline) (3). X-ray structural determination indicates that all of the title complexes crystallize in the same triclinic crystal system with space group p 1 bar . Complex 1 displays a symmetrical trinuclear aggregate, while complexs 2 and 3 display mononuclear structures. All the NPA ligands adopt total different coordination modes in complexes 1, 2 and 3. The comparison of solid-state fluorescence spectra among 1, 2 and free NPA shows that 1 and 2 exist a large red-shifted emission compared to free NPA ligand.

  11. Trimethylglycine complexes with carboxylic acids and HF: solvation by a polar aprotic solvent.

    PubMed

    Guo, Jing; Koeppe, Benjamin; Tolstoy, Peter M

    2011-02-14

    A series of strong H-bonded complexes of trimethylglycine, also known as betaine, with acetic, chloroacetic, dichloroacetic, trifluoroacetic and hydrofluoric acids as well as the homo-conjugated cation of betaine with trifluoroacetate as the counteranion were investigated by low-temperature (120-160 K) liquid-state NMR spectroscopy using CDF(3)/CDF(2)Cl mixture as the solvent. The temperature dependencies of (1)H NMR chemical shifts are analyzed in terms of the solvent-solute interactions. The experimental data are explained assuming the combined action of two main effects. Firstly, the solvent ordering around the negatively charged OHX region of the complex (X = O, F) at low temperatures, which leads to a contraction and symmetrisation of the H-bond; this effect dominates for the homo-conjugated cation of betaine. Secondly, at low temperatures structures with a larger dipole moment are preferentially stabilized, an effect which dominates for the neutral betaine-acid complexes. The way this second contribution affects the H-bond geometry seems to depend on the proton position. For the Be(+)COO(-)···HOOCCH(3) complex (Be = (CH(3))(3)NCH(2)-) the proton displaces towards the hydrogen bond center (H-bond symmetrisation, O···O contraction). In contrast, for the Be(+)COOH···(-)OOCCF(3) complex the proton shifts further away from the center, closer to the betaine moiety (H-bond asymmetrisation, O···O elongation). Hydrogen bond geometries and their changes upon lowering the temperature were estimated using previously published H-bond correlations. PMID:21132169

  12. Aminoglycosides prevent and dissociate the aggregation of platelets in patients with EDTA-dependent pseudothrombocytopenia.

    PubMed

    Sakurai, S; Shiojima, I; Tanigawa, T; Nakahara, K

    1997-12-01

    Although EDTA-dependent pseudothrombocytopenia (EDTA-PTCP) is of practical importance because failure to recognize this clinical entity may result in misdiagnosis and subsequent mismanagement of the patients, the pathophysiological nature of EDTA-PTCP remains unknown. To develop an effective way to evaluate the platelet counts in patients with EDTA-PTCP, we introduced aminoglycosides-supplemented anticoagulating agents. When kanamycin was pre-supplemented with EDTA for anticoagulating blood samples from EDTA-PTCP patients there was no significant change in the platelet counts and the morphology of blood cells after 150 min of incubation at room temperature. Furthermore, when kanamycin was added to EDTA-anticoagulated blood samples from EDTA-PTCP patients within 30 min after blood withdrawal, rapid dissociation of platelets without apparent morphological changes of blood cells was observed, and complete blood cell counts as well as the histogram patterns were almost the same as those examined immediately after blood sampling. The dissociation of aggregated platelets was also detected when other antibiotics were used, although it was associated with some extent of morphological changes of blood cells. These findings indicate that the supplementation of aminoglycosides either before or after blood sampling is a useful method for the diagnosis EDTA-PTCP and for the evaluation of platelet counts in patients with EDTA-PTCP. PMID:9432027

  13. An Aqueous Thermodynamic Model for the Complexation of Sodium and Strontium with Organic Chelators valid to High Ionic Strength. II. N-(2-hydroxyethyl)ethylenedinitrilotriacetic acid (HEDTA)

    SciTech Connect

    Felmy, Andrew R.; Mason, Marvin J.; Qafoku, Odeta

    2003-04-01

    This is the second paper in a two part series on the development of aqueous thermodynamic models for the complexation of Na+ and Sr2+ with organic chelators. In this paper the development of an aqueous thermodynamic model describing the effects of ionic strength, carbonate concentration, and temperature on the complexation of Sr2+ by HEDTA under basic conditions is presented. The thermodynamic model describing the Na+ interactions with the HEDTA3- chelate relies solely on the use of Pitzer ion-interaction parameters. The exclusive use of Pitzer ion-interaction parameters differs significantly from our previous model for EDTA, which required the introduction of a NaEDTA3- ion pair. Estimation of the Pitzer ion-interaction parameters for HEDTA3- and SrHEDTA- with Na+ allows the extrapolation of a standard state equilibrium constant for the SrHEDTA- species which is one order of magnitude greater than the 0.1M reference state value available in the literature. The overall model is developed from data available in the literature on apparent equilibrium constants for HEDTA protonation, the solubility of salts in concentrated HEDTA solutions, and from new data on the solubility of SrCO3(c) obtained as part of this study. The predictions of the final thermodynamic model for the Na-Sr-OH-CO3-NO3-HEDTA-H2O system are tested by application to chemical systems containing competing metal ions (i.e., Ca2+).

  14. Molecular structure of hydrated complex of trigonelline with L(+)-tartaric acid

    NASA Astrophysics Data System (ADS)

    Dega-Szafran, Z.; Dutkiewicz, G.; Kosturkiewicz, Z.; Szafran, M.; Barczyński, P.

    2011-04-01

    Crystal structure of the 1:1:1 complex of trigonelline with L(+)-tartaric acid and water has been determined by X-ray diffraction. The crystals are monoclinic, space group P2 1. Trigonelline is protonated and it is linked with the semi-tartrate anion by the COOH⋯OOC hydrogen bond of 2.475(2) Å. The semi-tartrate anions form infinite chains through the COOH⋯OOC hydrogen bonds of 2.599(2) Å. Water molecules play a role of double donors and double acceptors of hydrogen bonds with the semi-tartrate anions and link them into a three-dimensional net. In the optimized structure of the title complex at the B3LYP/6-31G(d,p) level of theory trigonelline is linked with L(+)-tartaric acid by the COO⋯HOOC hydrogen bond of 2.473 Å. The solid-state FTIR spectrum is consistent with the X-ray results. The 1H and 13C NMR spectra elucidate the structure of the complex investigated in aqueous solutions. The value of p Ka of trigonelline has been determined by the potentiometric titration of its hydrochloride.

  15. Bioavailability of an R-α-Lipoic Acid/γ-Cyclodextrin Complex in Healthy Volunteers

    PubMed Central

    Ikuta, Naoko; Okamoto, Hinako; Furune, Takahiro; Uekaji, Yukiko; Terao, Keiji; Uchida, Ryota; Iwamoto, Kosuke; Miyajima, Atsushi; Hirota, Takashi; Sakamoto, Norihiro

    2016-01-01

    R-α-lipoic acid (R-LA) is a cofactor of mitochondrial enzymes and a very strong antioxidant. R-LA is available as a functional food ingredient but is unstable against heat or acid. Stabilized R-LA was prepared through complexation with γ-cyclodextrin (CD), yielding R-LA/CD. R-LA/CD was orally administered to six healthy volunteers and showed higher plasma levels with an area under the plasma concentration-time curve that was 2.5 times higher than that after oral administration of non-complexed R-LA, although the time to reach the maximum plasma concentration and half-life did not differ. Furthermore, the plasma glucose level after a single oral administration of R-LA/CD or R-LA was not affected and no side effects were observed. These results indicate that R-LA/CD could be easily absorbed in the intestine. In conclusion, γ-CD complexation is a promising technology for delivering functional but unstable ingredients like R-LA. PMID:27314343

  16. 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

  17. Luminescent properties of europium(III) and terbium(III) complexes with para- and ortho-ethoxybenzoic acids

    NASA Astrophysics Data System (ADS)

    Panyushkin, V. T.; Mutuzova, M. Kh.; Shamsutdinova, M. Kh.

    2016-02-01

    The luminescent properties of europium(III) and terbium(III) complexes with para- and ortho-ethoxybenzoic acids are studied. The excitation energies of the triplet states of ligands are determined, a hypothesis is made about the efficient luminescence of europium(III) and terbium(III) complexes, the geometry of the coordination polyhedron of a europium complex is established, and the luminescence quantum yields of the complexes in solution are determined.

  18. Formation of host-guest complexes of β-cyclodextrin and perfluorooctanoic acid.

    PubMed

    Karoyo, Abdalla H; Borisov, Alex S; Wilson, Lee D; Hazendonk, Paul

    2011-08-11

    Structural characterization and dynamic properties of solid-state inclusion complexes of β-cyclodextrin (β-CD) with perfluorooctanoic acid (PFOA) were investigated by (19)F/(13)C solid-state and (19)F/(1)H solution NMR spectroscopy. The complexes in the solid state were prepared using dissolution and slow cool methods, where thermal analyses (DSC and TGA), PXRD, and FT-IR results provided complementary support that inclusion complexes were formed between β-CD and PFOA with variable stoichiometry and inclusion geometry. (19)F DP (direct polarization) and (13)C CP (cross-polarization) with magic-angle spinning (MAS) solids NMR, along with (19)F/(1)H solution NMR were used to characterize the complexes in the solid and solution phases, respectively. The dynamics of the guest molecules in the inclusion complexes (ICs) were studied using variable temperature (VT) (19)F DP/MAS NMR experiments in the solid state. The guest molecules were observed to be in several different molecular environments, providing strong evidence of variable host-guest stoichiometry and inclusion geometry, in accordance with the preparation method of the complex and the conformational preference of PFOA. It was concluded from PXRD that β-CD and PFOA form inclusion complexes with "channel-type" structures. Variable spin rate (VSR) (19)F DP/MAS NMR was used to assess the phase purity of the complexes, and it was revealed that slow cooling resulted in relatively pure phases. In the solution state, (1)H and (19)F NMR complexation-induced chemical shifts (CISs) of β-CD and PFOA, respectively, provided strong support for the formation of 1:1 and 2:1 β-CD/PFOA inclusion complexes. The dynamics of the guest molecule in the β-CD/PFOA complexes in D(2)O solutions were probed using VT (19)F NMR and revealed some guest conformational and exchange dynamics as a function of temperature and the relative concentrations of the host and guest. PMID:21688796

  19. Differential inhibitory effects of methylmalonic acid on respiratory chain complex activities in rat tissues.

    PubMed

    Pettenuzzo, Leticia F; Ferreira, Gustavo da C; Schmidt, Anna Laura; Dutra-Filho, Carlos S; Wyse, Angela T S; Wajner, Moacir

    2006-02-01

    Methylmalonic acidemia is an inherited metabolic disorder biochemically characterized by tissue accumulation of methylmalonic acid (MMA) and clinically by progressive neurological deterioration and kidney failure, whose pathophysiology is so far poorly established. Previous studies have shown that MMA inhibits complex II of the respiratory chain in rat cerebral cortex, although no inhibition of complexes I-V was found in bovine heart. Therefore, in the present study we investigated the in vitro effect of 2.5mM MMA on the activity of complexes I-III, II, II-III and IV in striatum, hippocampus, heart, liver and kidney homogenates from young rats. We observed that MMA caused a significant inhibition of complex II activity in striatum and hippocampus (15-20%) at low concentrations of succinate in the medium, but not in the peripheral tissues. We also verified that the inhibitory property of MMA only occurred after exposing brain homogenates for at least 10 min with the acid, suggesting that this inhibition was mediated by indirect mechanisms. Simultaneous preincubation with the nitric oxide synthase inhibitor Nomega-nitro-L-arginine methyl ester (L-NAME) and catalase (CAT) plus superoxide dismutase (SOD) did not prevent MMA-induced inhibition of complex II, suggesting that common reactive oxygen (superoxide, hydrogen peroxide and hydroxyl radical) and nitric (nitric oxide) species were not involved in this effect. In addition, complex II-III (20-35%) was also inhibited by MMA in all tissues tested, and complex I-III only in the kidney (53%) and liver (38%). In contrast, complex IV activity was not changed by MMA in all tissues studied. These results indicate that MMA differentially affects the activity of the respiratory chain pending on the tissues studied, being striatum and hippocampus more vulnerable to its effect. In case our in vitro data are confirmed in vivo in tissues from methylmalonic acidemic patients, it is feasible that that the present findings may be

  20. Water oxidation catalysis with nonheme iron complexes under acidic and basic conditions: homogeneous or heterogeneous?

    PubMed

    Hong, Dachao; Mandal, Sukanta; Yamada, Yusuke; Lee, Yong-Min; Nam, Wonwoo; Llobet, Antoni; Fukuzumi, Shunichi

    2013-08-19

    Thermal water oxidation by cerium(IV) ammonium nitrate (CAN) was catalyzed by nonheme iron complexes, such as Fe(BQEN)(OTf)2 (1) and Fe(BQCN)(OTf)2 (2) (BQEN = N,N'-dimethyl-N,N'-bis(8-quinolyl)ethane-1,2-diamine, BQCN = N,N'-dimethyl-N,N'-bis(8-quinolyl)cyclohexanediamine, OTf = CF3SO3(-)) in a nonbuffered aqueous solution; turnover numbers of 80 ± 10 and 20 ± 5 were obtained in the O2 evolution reaction by 1 and 2, respectively. The ligand dissociation of the iron complexes was observed under acidic conditions, and the dissociated ligands were oxidized by CAN to yield CO2. We also observed that 1 was converted to an iron(IV)-oxo complex during the water oxidation in competition with the ligand oxidation. In addition, oxygen exchange between the iron(IV)-oxo complex and H2(18)O was found to occur at a much faster rate than the oxygen evolution. These results indicate that the iron complexes act as the true homogeneous catalyst for water oxidation by CAN at low pHs. In contrast, light-driven water oxidation using [Ru(bpy)3](2+) (bpy = 2,2'-bipyridine) as a photosensitizer and S2O8(2-) as a sacrificial electron acceptor was catalyzed by iron hydroxide nanoparticles derived from the iron complexes under basic conditions as the result of the ligand dissociation. In a buffer solution (initial pH 9.0) formation of the iron hydroxide nanoparticles with a size of around 100 nm at the end of the reaction was monitored by dynamic light scattering (DLS) in situ and characterized by X-ray photoelectron spectra (XPS) and transmission electron microscope (TEM) measurements. We thus conclude that the water oxidation by CAN was catalyzed by short-lived homogeneous iron complexes under acidic conditions, whereas iron hydroxide nanoparticles derived from iron complexes act as a heterogeneous catalyst in the light-driven water oxidation reaction under basic conditions. PMID:23895380

  1. Formation constants of ternary complexes of some heavy metal ions with N-(2-acetamido)iminodiacetic acid and aliphatic or aromatic acids

    SciTech Connect

    Hamed, M.M.A.; Mahmoud, M.R. . Dept. of Chemistry); Saleh, M.B.; Ahmed, I.T. . Dept. of Chemistry)

    1994-07-01

    N-(2-Acetamido)iminodiacetic acid (H[sub 2]ADA) is considered as one of the biologically important ligands. It is used as a complexing agent in the field of metal ion buffers working at the physiological pH range. Furthermore, it is widely used as an analytical chelating agent for the spectrophotometric determination of metal ions. Solution equilibria of the ternary systems involving La(III), Y(III), Ce(III), and UO[sub 2][sup 2+], N-(2-acetamido)iminodiacetic acid, and some aliphatic or aromatic acids have been investigated potentiometrically. The formation of 1:1:1 mixed ligand complexes is inferred from the potentiometric titration curves. Formation constants of the different binary and ternary complexes formed in such systems were determined at 25 [+-] 0.1 C and [mu] = 0.1 mol dm[sup [minus]3] (KNO[sub 3]). It is deduced that the mixed ligand complexes are more stable than the corresponding binary complexes containing the aliphatic or aromatic acidate moiety. The order of stability of the binary and ternary complexes is investigated and discussed in terms of the nature of both the metal ion and the secondary ligand (aliphatic or aromatic acid).

  2. Inclusion complex of ellagic acid with β-cyclodextrin: Characterization and in vitro anti-inflammatory evaluation

    NASA Astrophysics Data System (ADS)

    Bulani, Vipin D.; Kothavade, Pankaj S.; Kundaikar, Harish S.; Gawali, Nitin B.; Chowdhury, Amrita A.; Degani, Mariam S.; Juvekar, Archana R.

    2016-02-01

    Freeze-dried inclusion complex of ellagic acid/β-cyclodextrin (EACD) was investigated both in solution and solid state by means of aqueous solubility, in vitro dissolution, absorption, fluorescence, Fourier transform infrared spectroscopy (FTIR), powder X-ray diffractometry (XRD), scanning electron microscopy (SEM), nuclear magnetic resonance (NMR) and molecular modeling methods. The phase solubility study showed that ellagic acid formed 1:2 stoichiometric inclusion complex with β-cyclodextrin (β-CD). The FTIR study indicates that carbonyl group of ellagic acid interact with β-CD. The NMR results demonstrate that ellagic acid was partly included into the β-CD from the wider side of the cavity. Molecular modeling studies revealed that hydrogen bonding interactions played an important role in the inclusion process and higher negative values for the complexation energies imply that 1:2 complex was more stable than 1:1 complex. The solubility and in vitro dissolution of ellagic acid was significantly enhanced by complexation with β-CD as compared to the free ellagic acid. Additionally, the complexation of EACD positively influences it's in vitro anti-inflammatory activity by protecting from protein denaturation and lysis of erythrocyte membrane.

  3. Chlorogenic acid ameliorates intestinal mitochondrial injury by increasing antioxidant effects and activity of respiratory complexes.

    PubMed

    Zhou, Yan; Zhou, Lili; Ruan, Zheng; Mi, Shumei; Jiang, Min; Li, Xiaolan; Wu, Xin; Deng, Zeyuan; Yin, Yulong

    2016-05-01

    Dietary polyphenols are thought to be beneficial for human health by acting as antioxidants. Chlorogenic acid (CGA) is abundant in plant-based foods as an ester of caffeic acid and quinic acid. In this study, we investigated the effects of CGA on mitochondrial protection. Our results demonstrated that pretreatment with CGA ameliorated the intestinal mitochondrial injury induced by H2O2; membrane potential was increased, mitochondrial swelling, levels of reactive oxygen species, contents of 8-hydroxy-2-deoxyguanosine, and cytochrome c released were decreased. The beneficial effects of CGA were accompanied by an increase in antioxidant and respiratory-chain complex I, IV, and V activities. In trinitrobenzene-sulfonic acid-induced colitic rats indicated that CGA supplementation improved mitochondria ultrastructure and decreased mitochondrial injury. Our results suggest a promising role for CGA as a mitochondria-targeted antioxidant in combating intestinal oxidative injury. Daily intake of diets containing CGA, such as coffee and honeysuckle, may be useful for prevention of intestinal diseases. PMID:26824685

  4. Self-assembled ternary complexes stabilized with hyaluronic acid-green tea catechin conjugates for targeted gene delivery.

    PubMed

    Liang, Kun; Bae, Ki Hyun; Lee, Fan; Xu, Keming; Chung, Joo Eun; Gao, Shu Jun; Kurisawa, Motoichi

    2016-03-28

    Nanosized polyelectrolyte complexes are attractive delivery vehicles for the transfer of therapeutic genes to diseased cells. Here we report the application of self-assembled ternary complexes constructed with plasmid DNA, branched polyethylenimine and hyaluronic acid-green tea catechin conjugates for targeted gene delivery. These conjugates not only stabilize plasmid DNA/polyethylenimine complexes via the strong DNA-binding affinity of green tea catechin, but also facilitate their transport into CD44-overexpressing cells via receptor-mediated endocytosis. The hydrodynamic size, surface charge and physical stability of the complexes are characterized. We demonstrate that the stabilized ternary complexes display enhanced resistance to nuclease attack and polyanion-induced dissociation. Moreover, the ternary complexes can efficiently transfect the difficult-to-transfect HCT-116 colon cancer cell line even in serum-supplemented media due to their enhanced stability and CD44-targeting ability. Confocal microscopic analysis demonstrates that the stabilized ternary complexes are able to promote the nuclear transport of plasmid DNA more effectively than binary complexes and hyaluronic acid-coated ternary complexes. The present study suggests that the ternary complexes stabilized with hyaluronic acid-green tea catechin conjugates can be widely utilized for CD44-targeted delivery of nucleic acid-based therapeutics. PMID:26855049

  5. One-Step Assembly of Phytic Acid Metal Complexes for Superhydrophilic Coatings.

    PubMed

    Li, Longbiao; Zhang, Guangyu; Su, Zhaohui

    2016-07-25

    While of immense scientific interest, superhydrophilic surfaces are usually difficult to prepare, and preparation methods are typically substrate specific. Herein, a one-step coating method is described that can endow superhydrophilicity to a variety of substrates, both inorganic and organic, using the coordination complexes of natural phytic acid and Fe(III) ions. Coating deposition occurs in minutes, and coatings are ultrathin, colorless, and transparent. Superhydrophilicity is attributed, in part, to the high density of phosphonic acid groups. The ease, rapidness, and mildness of the assembly process, which is also cost-effective and environmental-friendly, points towards potential applications, such as self-cleaning, oil/water separation, antifogging. PMID:27377349

  6. Modeling of fermentation with continuous lactic acid removal by extraction utilizing reversible chemical complexation

    SciTech Connect

    Dai, Y.; King, C.J.

    1995-07-01

    Extractive fermentation is a technique that can be used to reduce end-product inhibition by removing fermentation products in situ or in an external recycle loop. A model is presented for fermentation with continuous lactic acid removal by extraction utilizing chemical complexation. The model is formulated considering the kinetics of cell growth and the equilibrium distribution of lactic acid between aqueous and organic phases. Simulations have been carried out for different sets of operating conditions. The choice of pH balances faster kinetics at higher pH against lower product concentrations in the solvent and more difficult regeneration. A key need is for liquid extractants or solid sorbents combining stronger uptake ability with economical regeneration and satisfactory biocompatibility.

  7. A ω-mercaptoundecylphosphonic acid chemically modified gold electrode for uranium determination in waters in presence of organic matter.

    PubMed

    Merli, Daniele; Protti, Stefano; Labò, Matteo; Pesavento, Maria; Profumo, Antonella

    2016-05-01

    A chemically modified electrode (CME) on a gold surface assembled with a ω-phosphonic acid terminated thiol was investigated for its capability to complex uranyl ions. The electrode, characterized by electrochemical techniques, demonstrated to be effective for the determination of uranyl at sub-μgL(-1) level by differential pulse adsorptive stripping voltammetry (DPAdSV) in environmental waters, also in presence of humic matter and other potential chelating agents. The accuracy of the measurements was investigated employing as model probes ligands of different complexing capability (humic acids and EDTA). PMID:26946018

  8. Anion-π interactions in complexes of proteins and halogen-containing amino acids.

    PubMed

    Borozan, Sunčica Z; Zlatović, Mario V; Stojanović, Srđan Đ

    2016-06-01

    We analyzed the potential influence of anion-π interactions on the stability of complexes of proteins and halogen-containing non-natural amino acids. Anion-π interactions are distance and orientation dependent and our ab initio calculations showed that their energy can be lower than -8 kcal mol(-1), while most of their interaction energies lie in the range from -1 to -4 kcal mol(-1). About 20 % of these interactions were found to be repulsive. We have observed that Tyr has the highest occurrence among the aromatic residues involved in anion-π interactions, while His made the least contribution. Furthermore, our study showed that 67 % of total interactions in the dataset are multiple anion-π interactions. Most of the amino acid residues involved in anion-π interactions tend to be buried in the solvent-excluded environment. The majority of the anion-π interacting residues are located in regions with helical secondary structure. Analysis of stabilization centers for these complexes showed that all of the six residues capable of anion-π interactions are important in locating one or more of such centers. We found that anion-π interacting residues are sometimes involved in simultaneous interactions with halogens as well. With all that in mind, we can conclude that the anion-π interactions can show significant influence on molecular organization and on the structural stability of the complexes of proteins and halogen-containing non-natural amino acids. Their influence should not be neglected in supramolecular chemistry and crystal engineering fields as well. PMID:26910415

  9. Encapsulation of gallic acid/cyclodextrin inclusion complex in electrospun polylactic acid nanofibers: Release behavior and antioxidant activity of gallic acid.

    PubMed

    Aytac, Zeynep; Kusku, Semran Ipek; Durgun, Engin; Uyar, Tamer

    2016-06-01

    Cyclodextrin-inclusion complexes (CD-ICs) possess great prominence in food and pharmaceutical industries due to their enhanced ability for stabilization of active compounds during processing, storage and usage. Here, CD-IC of gallic acid (GA) with hydroxypropyl-beta-cyclodextrin (GA/HPβCD-IC) was prepared and then incorporated into polylactic acid (PLA) nanofibers (PLA/GA/HPβCD-IC-NF) using electrospinning technique to observe the effect of CD-ICs in the release behavior of GA into three different mediums (water, 10% ethanol and 95% ethanol). The GA incorporated PLA nanofibers (PLA/GA-NFs) were served as control. Phase solubility studies showed an enhanced solubility of GA with increasing amount of HPβCD. The detailed characterization techniques (XRD, TGA and (1)H-NMR) confirmed the formation of inclusion complex between GA and HPβCD. Computational modeling studies indicated that the GA made an efficient complex with HPβCD at 1:1 either in vacuum or aqueous system. SEM images revealed the bead-free and uniform morphology of PLA/GA/HPβCD-IC-NF. The release studies of GA from PLA/GA/HPβCD-IC-NF and PLA/GA-NF were carried out in water, 10% ethanol and 95% ethanol, and the findings revealed that PLA/GA/HPβCD-IC-NF has released much more amount of GA in water and 10% ethanol system when compared to PLA/GA-NF. In addition, GA was released slowly from PLA/GA/HPβCD-IC-NF into 95% ethanol when compared to PLA/GA-NF. It was also observed that electrospinning process had no negative effect on the antioxidant activity of GA when GA was incorporated in PLA nanofibers. PMID:27040215

  10. Acridine-based complex as amino acid anion fluorescent sensor in aqueous solution

    NASA Astrophysics Data System (ADS)

    Dai, Yanpeng; Xu, Kuoxi; Li, Qian; Wang, Chaoyu; Liu, Xiaoyan; Wang, Peng

    2016-03-01

    Novel acridine-based fluorescence sensors containing alaninol ligands, L1 and D1, were designed and synthesized. The structure of the compound was characterized by IR, 1H NMR, 13C NMR, MS spectra. L1 and D1 possess efficient Cu2 + cation ON-OFF selective signaling behavior based on ligand-to-metal binding mechanism at physiological pH condition. Additionally, the L1-Cu(II) and D1-Cu(II) complexes could further serve as reversible OFF-ON signaling sensing ensemble to allow ratiometric response to amino acid anion in aqueous solution.

  11. Formic acid dehydrogenation catalysed by ruthenium complexes bearing the tripodal ligands triphos and NP3.

    PubMed

    Mellone, Irene; Peruzzini, Maurizio; Rosi, Luca; Mellmann, Dörthe; Junge, Henrik; Beller, Matthias; Gonsalvi, Luca

    2013-02-21

    The selective formic acid dehydrogenation to a mixture of CO(2) and H(2) was achieved with moderate to good productivities in the presence of homogeneous Ru catalysts bearing the polydentate tripodal ligands 1,1,1-tris-(diphenylphosphinomethyl)ethane (triphos) and tris-[2-(diphenylphosphino)ethyl]amine (NP(3)), either made in situ from suitable Ru(III) precursors or as molecular complexes. Preliminary mechanistic studies highlighting subtle differences due to ligand effects in the corresponding systems under study are also presented. PMID:23212285

  12. Fatty acid ethanolamide levels are altered in borderline personality and complex posttraumatic stress disorders.

    PubMed

    Schaefer, Carola; Enning, Frank; Mueller, Juliane K; Bumb, J Malte; Rohleder, Cathrin; Odorfer, Thorsten M; Klosterkötter, Joachim; Hellmich, Martin; Koethe, Dagmar; Schmahl, Christian; Bohus, Martin; Leweke, F Markus

    2014-08-01

    Borderline personality (BPD) and complex posttraumatic stress disorders (PTSD) are both powerfully associated with the experience of interpersonal violence during childhood and adolescence. The disorders frequently co-occur and often result in pervasive problems in, e.g., emotion regulation and altered pain perception, where the endocannabinoid system is deeply involved. We hypothesize an endocannabinoid role in both disorders. We investigated serum levels of the endocannabinoids anandamide and 2-arachidonoylglycerol and related fatty acid ethanolamides (FAEs) in BPD, PTSD, and controls. Significant alterations were found for both endocannabinoids in BPD and for the FAE oleoylethanolamide in PTSD suggesting a respective link to both disorders. PMID:24253425

  13. Synthesis, structural characterization and antimicrobial activities of diorganotin(IV) complexes with azo-imino carboxylic acid ligand: Crystal structure and topological study of a doubly phenoxide-bridged dimeric dimethyltin(IV) complex appended with free carboxylic acid groups

    NASA Astrophysics Data System (ADS)

    Roy, Manojit; Roy, Subhadip; Devi, N. Manglembi; Singh, Ch. Brajakishor; Singh, Keisham Surjit

    2016-09-01

    Diorganotin(IV) complexes appended with free carboxylic acids were synthesized by reacting diorganotin(IV) dichlorides [R2SnCl2; R = Me (1), Bu (2) and Ph (3)] with an azo-imino carboxylic acid ligand i.e. 2-{4-hydroxy-3-[(2-hydroxyphenylimino)methyl]phenylazo}benzoic acid in presence of triethylamine. The complexes were characterized by elemental analysis, IR and multinuclear NMR (1H, 13C and 119Sn) spectroscopy. The structure of 1 in solid state has been determined by X-ray crystallography. Crystal structure of 1 reveals that the compound crystallizes in monoclinic space group P21/c and is a dimeric dimethyltin(IV) complex appended with free carboxylic acid groups. In the structure of 1, the Sn(IV) atoms are hexacoordinated and have a distorted octahedral coordination geometry in which two phenoxy oxygen atoms and the azomethine nitrogen atom of the ligand coordinate to each tin atom. One of the phenoxy oxygen atom bridges the two tin centers resulting in a planar Sn2O2 core. Topological analysis is used for the description of molecular packing in 1. Tin NMR spectroscopy study indicates that the complexes have five coordinate geometry around tin atom in solution state. Since the complexes have free carboxylic acids, these compounds could be further used as potential metallo-ligands for the synthesis of other complexes. The synthesized diorganotin(IV) complexes were also screened for their antimicrobial activities and compound 2 showed effective antimicrobial activities.

  14. Structure and spectroscopic studies of homo-and heterometallic complexes of adipic acid dihydrazide.

    PubMed

    Jeragh, Bakir; El-Asmy, Ahmed A

    2014-05-01

    A single crystal of adipic acid dihydrazide, ADH, has been analyzed. Its reaction with Co(2+), Ni(2+), Cu(2+), Zn(2+), Cd(2+), Hg(2+), Ag(+), Pd(2+) and/or Pt(2+) gave homometallic and heterometallic complexes which are characterized by partial elemental analysis, spectra (MS, ESR, (1)H NMR, electronic; IR), thermal analysis and magnetic measurements. Some complexes: Zn(0.73)Cu(ADH)Cl4·H2O; Zn(0.71)Hg(0.36)(ADH)Cl4·H2O; Zn(0.65)Cd(0.46)(ADH)Cl4·½H2O; Zn(0.75)Co(0.41)(ADH-2H)Cl2·3H2O; Cd0.85Co0.43(ADH)Cl4·½EtOH were isolated having nonstiochiometric metal ratios. The ligand behaves as a neutral (bidentate or tetradentate) and/or binegative tetradentate. A square-pyramid, square-planar and tetrahedral structures were proposed for the homo Co(II), Cu(II) and Ni(II) complexes, respectively. A similar and different stereochemistry around each metal ion (tetrahedral+tetrahedral; tetrahedral+square-planar; tetrahedral+tetrahedral and/or tetrahedral+octahedral) was suggested for the heterometallic complexes. Some complexes were found highly stable with stability point >240 °C; the most stable is [HgNi(ADH-2H)Cl2]. The presence of diamagnetic atom (Zn, Cd or Hg) reduces the magnetic moments and gave anomalous moments. The degradation steps and the hydrated complexes are confirmed through the TGA study. The order of covalency of [Zn(0.73)Cu(ADH)Cl4]·H2O, [CdCu(ADH)Cl4]·H2O and [HgCu(ADH-2H)Cl2] matches with the size of the second metal (Zn complex>Cd complex>Hg complex). Some heterometallic complexes were found nonstoichiometric through the analysis of their metal content and supported by TGA. PMID:24530707

  15. Structure and spectroscopic studies of homo-and heterometallic complexes of adipic acid dihydrazide

    NASA Astrophysics Data System (ADS)

    Jeragh, Bakir; El-Asmy, Ahmed A.

    A single crystal of adipic acid dihydrazide, ADH, has been analyzed. Its reaction with Co2+, Ni2+, Cu2+, Zn2+, Cd2+, Hg2+, Ag+, Pd2+ and/or Pt2+ gave homometallic and heterometallic complexes which are characterized by partial elemental analysis, spectra (MS, ESR, 1H NMR, electronic; IR), thermal analysis and magnetic measurements. Some complexes: Zn0.73Cu(ADH)Cl4·H2O; Zn0.71Hg0.36(ADH)Cl4·H2O; Zn0.65Cd0.46(ADH)Cl4·½H2O; Zn0.75Co0.41(ADH-2H)Cl2·3H2O; Cd0.85Co0.43(ADH)Cl4·½EtOH were isolated having nonstiochiometric metal ratios. The ligand behaves as a neutral (bidentate or tetradentate) and/or binegative tetradentate. A square-pyramid, square-planar and tetrahedral structures were proposed for the homo Co(II), Cu(II) and Ni(II) complexes, respectively. A similar and different stereochemistry around each metal ion (tetrahedral + tetrahedral; tetrahedral + square-planar; tetrahedral + tetrahedral and/or tetrahedral + octahedral) was suggested for the heterometallic complexes. Some complexes were found highly stable with stability point >240 °C; the most stable is [HgNi(ADH-2H)Cl2]. The presence of diamagnetic atom (Zn, Cd or Hg) reduces the magnetic moments and gave anomalous moments. The degradation steps and the hydrated complexes are confirmed through the TGA study. The order of covalency of [Zn0.73Cu(ADH)Cl4]·H2O, [CdCu(ADH)Cl4]·H2O and [HgCu(ADH-2H)Cl2] matches with the size of the second metal (Zn complex > Cd complex > Hg complex). Some heterometallic complexes were found nonstoichiometric through the analysis of their metal content and supported by TGA.

  16. Plutonium (IV) complexation by nitrate in acid solutions of ionic strengths from 2 to 19 molal

    SciTech Connect

    Berg, J.M.; Veirs, D.K.; Vaughn, R.B.; Cisneros, M.A.; Smith, C.A.

    1997-09-01

    Titrations of Pu(IV) with HNO{sub 3} in a series of aqueous HClO{sub 4} solutions ranging in ionic strength from 2 to 19 molal were followed using absorption spectrophotometry. The Pu 5f-5f spectra in the visible and near IR range change with complex formation. At each ionic strength, a series of spectra were obtained by varying nitrate concentration. Each series was deconvoluted into spectra f Pu{sup 4+}(aq), Pu(NO{sub 3}){sup 3+} and Pu(NO{sub 3}){sub 2}{sup 2+} complexes, and simultaneously their formation constants were determined. When corrected for the incomplete dissociation of nitric acid, the ionic strength dependence of each formation constant can be described by two parameters, {beta}{sup 0} and {Delta}{var_epsilon} using the formulae of specific ion interaction theory. The difficulties with extending this analysis to higher nitrate coordination numbers are discussed.

  17. Survey on the complexation character of p-sulfonatocalix[n]arenes and Caffeic acid

    NASA Astrophysics Data System (ADS)

    Chao, Jianbin; Liu, Yuhong; Zhang, Yan; Wang, Yu; Zhao, Wei; Zhang, Bingtai

    2014-11-01

    In this work the inclusion complex formation of Caffeic acid (CA) with p-sulfonatocalix[n]arenes (SCXn, n = 4, 6, 8) is reported aiming to improve the antioxidant activity, thermal stability and photostability properties of CA. Evidence for the formation was obtained using fluorescence spectroscopy, nuclear magnetic resonance spectroscopy (NMR), pulsed field gradient NMR (PFG-NMR), Fourier transform infrared spectroscopy (FT-IR), differential scanning calorimetry (DSC) and scanning electron microphotographs (SEM). Experimental conditions including concentrations of SCXn and pH were investigated for the inclusion formation in detail. The results showed that CA was able to form inclusion complexes with SCXn in a molar ratio of 1:1, and the formation constants were varied with the pH conditions. NMR spectroscopy indicated that both the aromatic ring and the vinyl group of CA were partially covered by SCXn.

  18. Arachidonic acid stimulates formation of a novel complex containing nucleolin and RhoA.

    PubMed

    Garcia, Melissa C; Williams, Jason; Johnson, Katina; Olden, Kenneth; Roberts, John D

    2011-02-18

    Arachidonic acid (AA) stimulates cell adhesion through a p38 mitogen activated protein kinase-mediated RhoA signaling pathway. Here we report that a proteomic screen following AA-treatment identified nucleolin, a multifunctional nucleolar protein, in a complex with the GTPase, RhoA, that also included the Rho kinase, ROCK. AA-stimulated cell adhesion was inhibited by expression of nucleolin-targeted shRNA and formation of the multiprotein complex was blocked by expression of dominant-negative RhoA. AA-treatment also induced ROCK-dependent serine phosphorylation of nucleolin and translocation of nucleolin from the nucleus to the cytoplasm, where it appeared to co-localize with RhoA. These data suggest the existence of a new signaling pathway through which the location and post-translational state of nucleolin are modulated. PMID:21281639

  19. Complexes of fulvic acid on the surface of hematite, goethite, and akaganeite: FTIR observation.

    PubMed

    Fu, Hongbo; Quan, Xie

    2006-04-01

    The present work extended our knowledge on the binding and complexation of a fulvic acid (FA) derived from leonardite and the iron oxides (hematite, goethite and akaganeite) by Fourier transform infrared spectroscopy (FTIR). As a prerequisite, the iron oxides were firstly prepared and characterized by transmission electron micrograph (TEM). All iron phases were single and well-described crystalloid. The FTIR data obtained by two different sampling preparation methods gave the consisting evidences that under our experimental conditions the interaction mechanism was to the ligand-exchange involving carboxylic functional groups of the FA and the surfaces sites of both hematite and goethite, while no complexation can be evidenced in the case of akaganeite, only surface adsorption. In general, the binding affinities of the iron oxides with the FA was in the order of hematite>goethite>akaganeite. The present method, although associated with some uncertainties, provided an opportunity to increase the knowledge in the field of the humic chemistry. PMID:16293289

  20. Effect of chelating agents and solubility of cadmium complexes on uptake from soil by Brassica juncea.

    PubMed

    Van Engelen, Debra L; Sharpe-Pedler, Rachel C; Moorhead, Kevin K

    2007-06-01

    Brassica juncea, or Indian mustard, was grown in soil artificially contaminated with either a soluble salt, CdCl(2), at 186mg Cdkg(-1), or alternately an insoluble, basic salt, CdCO(3), at 90mg Cdkg(-1). These experiments study the range of Cd uptake by Indian mustard from conditions of very high Cd concentration in a soluble form to the other extreme with an insoluble Cd salt. After plants were established, four different chelating agents were applied. Chelating agents increased plant uptake of Cd from the CdCl(2) soil but did not significantly increase plant uptake of Cd from the CdCO(3) contaminated soil. Addition of ethylenediaminetetraacetic acid (EDTA) increased the plant concentration of Cd by almost 10-fold in soils contaminated with CdCl(2), with a concentration of 1283mg Cdkg(-1) in the dried EDTA-treated plants over a concentration of 131mg Cdkg(-1) in plants without added chelate. However, EDTA increased the aqueous solubility of Cd by 36 times over the soil matrix without added chelator, and thereby, increased the possibility of leaching. Other chelators used in both experiments were ethylenebis(oxyethylenenitrilo)tetraacetic acid, trans-1,2-diaminocyclohexane-N,N,N',N'-tetraacetic acid, and diethylenetriaminepentaacetic acid (DTPA) increasing Cd in plants to 1240, 962, and 437mg Cdkg(-1), respectively. The other chelating agents increased the solubility of Cd in the leachate but not to the extent of EDTA. Comparing all chelating agents studied, DTPA increased plant uptake in terms of Cd in dried plant concentration most relative to the solubility of complexed Cd in runoff water. PMID:17320931

  1. Toxicity to embryo and adult zebrafish of copper complexes with two malonic acids as models for dissolved organic matter

    SciTech Connect

    Palmer, F.B.; Evans, C.W.; Butler, C.A.; Timperley, M.H.

    1998-08-01

    The toxicity to embryo and adult zebrafish (Danio rerio) of Cu complexes with two substituted malonic acids, benzyl- and n-hexadecyl-, chosen as models for low-molecular-weight natural dissolved organic matter, were investigated. Toxicity test solutions at pH 6.5 {+-} 0.1 with the required Cu ion-specific electrode. In the absence of malonic acids, concentrations of Cu{sup 2+} up to 1.13 {mu}mol/L increased the embryo hatching time from approx. 2 d in control solutions (no Cu or malonic acid) and solutions containing malonic acids without Cu to approx. 8 d. The Cu-benzylmalonic acid complex in the presence of inorganic Cu species did not delay hatching beyond that attributable to Cu{sup 2+}. In contrast, 0.60 {mu}mol/L Cu-n-hexadecylmalonic complexes delayed hatching by 5.5 d in excess of that attributable to 1.13 {mu}mol/L Cu{sup 2+}, assuming that the hatching delays caused by the different Cu species were additive, possibly because of Cu entry into the embryo as the lipophilic Cu-n-hexadecylmalonic complex. None of the Cu-malonic acid complexes was acutely toxic to adult zebrafish at concentrations up to 1.4 {mu}mol/L, possibly because Cu was removed from the Cu-malonic acid complexes by stronger chelating groups at the gill surface. Substituted malonic acids with similar proton and Cu association constants can be readily prepared with a variety of simple substituents, radiolabeled if required. Their results show that these acids could be useful ligands for investigating intracellular transport and metabolism of metal-organic complexes.

  2. Synthesis and characterization of tin(II) complexes of fluorinated Schiff bases derived from amino acids

    NASA Astrophysics Data System (ADS)

    Singh, Har Lal

    2010-07-01

    New tin(II) complexes of general formula Sn(L) 2 (L = monoanion of 3-methyl-4-fluoro-acetophenone phenylalanine L 1H, 3-methyl-4-fluoro-acetophenone alanine L 2H, 3-methyl-4-fluoro acetophenone tryptophan L 3H, 3-methyl-4-fluoro-acetophenone valine L 4H, 3-methyl-4-fluoro-acetophenone isoleucine L 5H and 3-methyl-4-fluoro-acetophenone glycine L 6H) have been prepared. It is characterized by elemental analyses, molar conductance measurements and molecular weight determinations. Bonding of these complexes is discussed in terms of their UV-visible, infrared, and nuclear magnetic resonance ( 1H, 13C, 19F and 119Sn NMR) spectral studies. The ligands act as bidentate towards metal ions, via the azomethine nitrogen and deprotonated oxygen of the respective amino acid. Elemental analyses and NMR spectral data of the ligands with their tin(II) complexes agree with their proposed square pyramidal structures. A few representative ligands and their tin complexes have been screened for their antibacterial activities and found to be quite active in this respect.

  3. Asymmetrical Macromolecular Complex Formation of Lysophosphatidic Acid Receptor 2 (LPA2) Mediates Gradient Sensing in Fibroblasts*

    PubMed Central

    Ren, Aixia; Moon, Changsuk; Zhang, Weiqiang; Sinha, Chandrima; Yarlagadda, Sunitha; Arora, Kavisha; Wang, Xusheng; Yue, Junming; Parthasarathi, Kaushik; Heil-Chapdelaine, Rick; Tigyi, Gabor; Naren, Anjaparavanda P.

    2014-01-01

    Chemotactic migration of fibroblasts toward growth factors relies on their capacity to sense minute extracellular gradients and respond to spatially confined receptor-mediated signals. Currently, mechanisms underlying the gradient sensing of fibroblasts remain poorly understood. Using single-particle tracking methodology, we determined that a lysophosphatidic acid (LPA) gradient induces a spatiotemporally restricted decrease in the mobility of LPA receptor 2 (LPA2) on chemotactic fibroblasts. The onset of decreased LPA2 mobility correlates to the spatial recruitment and coupling to LPA2-interacting proteins that anchor the complex to the cytoskeleton. These localized PDZ motif-mediated macromolecular complexes of LPA2 trigger a Ca2+ puff gradient that governs gradient sensing and directional migration in response to LPA. Disruption of the PDZ motif-mediated assembly of the macromolecular complex of LPA2 disorganizes the gradient of Ca2+ puffs, disrupts gradient sensing, and reduces the directional migration of fibroblasts toward LPA. Our findings illustrate that the asymmetric macromolecular complex formation of chemoattractant receptors mediates gradient sensing and provides a new mechanistic basis for models to describe gradient sensing of fibroblasts. PMID:25542932

  4. Structure and Stability of Carbohydrate-Lipid Interactions. Methylmannose Polysaccharide-Fatty Acid Complexes.

    PubMed

    Liu, Lan; Siuda, Iwona; Richards, Michele R; Renaud, Justin; Kitova, Elena N; Mayer, Paul M; Tieleman, D Peter; Lowary, Todd L; Klassen, John S

    2016-08-17

    We report a detailed study of the structure and stability of carbohydrate-lipid interactions. Complexes of a methylmannose polysaccharide (MMP) derivative and fatty acids (FAs) served as model systems. The dependence of solution affinities and gas-phase dissociation activation energies (Ea ) on FA length indicates a dominant role of carbohydrate-lipid interactions in stabilizing (MMP+FA) complexes. Solution (1) H NMR results reveal weak interactions between MMP methyl groups and FA acyl chain; MD simulations suggest the complexes are disordered. The contribution of FA methylene groups to the Ea is similar to that of heats of transfer of n-alkanes from the gas phase to polar solvents, thus suggesting that MMP binds lipids through dipole-induced dipole interactions. The MD results point to hydrophobic interactions and H-bonds with the FA carboxyl group. Comparison of collision cross sections of deprotonated (MMP+FA) ions with MD structures suggests that the gaseous complexes are disordered. PMID:27253157

  5. Preparation and characterization of aqueous dispersions of high amylose starch and conjugated linoleic acid complex.

    PubMed

    Seo, Tae-Rang; Kim, Hee-Young; Lim, Seung-Taik

    2016-11-15

    Crystalline starch-CLA complexes were prepared by blending an alcoholic solution of conjugated linoleic acid (CLA) in an aqueous high-amylose maize starch dispersion. Recovery yield of CLA in the precipitates obtained by centrifuging the dispersion was dependent on reaction conditions such as temperature, time and pH. The CLA recovery reached a maximum when the reaction was performed at 90°C for 6h at neutral pH, with 67.7% of the initial CLA being co-precipitated with starch. The precipitates contained amylose-CLA complex exhibiting a V6I-type crystalline structure under X-ray diffraction analysis and a type II polymorph under DSC analysis. Ultrasonic treatment for the re-dispersed starch-CLA complex in water resulted in the reduction of hydrodynamic diameter of the complex particles to 201.5nm. The dispersion exhibited a zeta potential of -27.0mV and remained stable in an ambient storage without forming precipitates for more than 4weeks. PMID:27283663

  6. Asymmetrical macromolecular complex formation of lysophosphatidic acid receptor 2 (LPA2) mediates gradient sensing in fibroblasts.

    PubMed

    Ren, Aixia; Moon, Changsuk; Zhang, Weiqiang; Sinha, Chandrima; Yarlagadda, Sunitha; Arora, Kavisha; Wang, Xusheng; Yue, Junming; Parthasarathi, Kaushik; Heil-Chapdelaine, Rick; Tigyi, Gabor; Naren, Anjaparavanda P

    2014-12-26

    Chemotactic migration of fibroblasts toward growth factors relies on their capacity to sense minute extracellular gradients and respond to spatially confined receptor-mediated signals. Currently, mechanisms underlying the gradient sensing of fibroblasts remain poorly understood. Using single-particle tracking methodology, we determined that a lysophosphatidic acid (LPA) gradient induces a spatiotemporally restricted decrease in the mobility of LPA receptor 2 (LPA2) on chemotactic fibroblasts. The onset of decreased LPA2 mobility correlates to the spatial recruitment and coupling to LPA2-interacting proteins that anchor the complex to the cytoskeleton. These localized PDZ motif-mediated macromolecular complexes of LPA2 trigger a Ca(2+) puff gradient that governs gradient sensing and directional migration in response to LPA. Disruption of the PDZ motif-mediated assembly of the macromolecular complex of LPA2 disorganizes the gradient of Ca(2+) puffs, disrupts gradient sensing, and reduces the directional migration of fibroblasts toward LPA. Our findings illustrate that the asymmetric macromolecular complex formation of chemoattractant receptors mediates gradient sensing and provides a new mechanistic basis for models to describe gradient sensing of fibroblasts. PMID:25542932

  7. Regulation of hepatic branched-chain alpha-keto acid dehydrogenase complex in rats fed a high-fat diet

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Objective: Branched-chain alpha-keto acid dehydrogenase complex (BCKDC) regulates branched-chain amino acid (BCAA) metabolism at the level of branched chain alpha-ketoacid (BCKA) catabolism. It has been demonstrated that the activity of hepatic BCKDC is markedly decreased in type 2 diabetic animal...

  8. Comparison of microwave processing and excess steam jet cooking for spherulite production from amylose-fatty acid inclusion complexes

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Helical inclusion complexes of amylose with fatty acids can form spherulites of various morphological types. Previous studies have described the spherulites obtained by cooling dispersions of steam jet cooked corn starch either by itself or supplemented with various fatty acids. In light of potent...

  9. Tuning the reactivity of mononuclear nonheme manganese(iv)-oxo complexes by triflic acid

    SciTech Connect

    Chen, Junying; Yoon, Heejung; Lee, Yong -Min; Seo, Mi Sook; Sarangi, Ritimukta; Fukuzumi, Shunichi; Nam, Wonwoo

    2015-04-14

    Triflic acid (HOTf)-bound nonheme Mn(IV)-oxo complexes, [(L)MnIV(O)]2+–(HOTf)2 (L = N4Py and Bn-TPEN; N4Py = N,N-bis(2-pyridylmethyl)-N-bis(2-pyridyl)methylamine and Bn-TPEN = N-benzyl-N,N',N'-tris(2-pyridylmethyl)ethane-1,2-diamine), were synthesized by adding HOTf to the solutions of the [(L)MnIV(O)]2+ complexes and were characterized by various spectroscopies. The one-electron reduction potentials of the MnIV(O) complexes exhibited a significant positive shift upon binding of HOTf. The driving force dependences of electron transfer (ET) from electron donors to the MnIV(O) and MnIV(O)–(HOTf)2 complexes were examined and evaluated in light of the Marcus theory of ET to determine the reorganization energies of ET. The smaller reorganization energies and much more positive reduction potentials of the [(L)MnIV(O)]2+–(HOTf)2 complexes resulted in greatly enhanced oxidation capacity towards one-electron reductants and para-X-substituted-thioanisoles. The reactivities of the Mn(IV)-oxo complexes were markedly enhanced by binding of HOTf, such as a 6.4 × 105-fold increase in the oxygen atom transfer (OAT) reaction (i.e., sulfoxidation). Such a remarkable acceleration in the OAT reaction results from the enhancement of ET from para-X-substituted-thioanisoles to the MnIV(O) complexes as revealed by the unified ET driving force dependence of the rate constants of OAT and ET reactions of [(L)MnIV(O)]2+–(HOTf)2. In contrast, deceleration was observed in the rate of H-atom transfer (HAT) reaction of [(L)MnIV(O)]2+–(HOTf)2 complexes with 1,4-cyclohexadiene as compared with those of the [(L)MnIV(O)]2+ complexes. Thus, the binding of two HOTf molecules to the MnIV(O) moiety resulted in remarkable acceleration of the ET

  10. Tuning the reactivity of mononuclear nonheme manganese(iv)-oxo complexes by triflic acid

    DOE PAGESBeta

    Chen, Junying; Yoon, Heejung; Lee, Yong -Min; Seo, Mi Sook; Sarangi, Ritimukta; Fukuzumi, Shunichi; Nam, Wonwoo

    2015-04-14

    Triflic acid (HOTf)-bound nonheme Mn(IV)-oxo complexes, [(L)MnIV(O)]2+–(HOTf)2 (L = N4Py and Bn-TPEN; N4Py = N,N-bis(2-pyridylmethyl)-N-bis(2-pyridyl)methylamine and Bn-TPEN = N-benzyl-N,N',N'-tris(2-pyridylmethyl)ethane-1,2-diamine), were synthesized by adding HOTf to the solutions of the [(L)MnIV(O)]2+ complexes and were characterized by various spectroscopies. The one-electron reduction potentials of the MnIV(O) complexes exhibited a significant positive shift upon binding of HOTf. The driving force dependences of electron transfer (ET) from electron donors to the MnIV(O) and MnIV(O)–(HOTf)2 complexes were examined and evaluated in light of the Marcus theory of ET to determine the reorganization energies of ET. The smaller reorganization energies and much more positive reduction potentialsmore » of the [(L)MnIV(O)]2+–(HOTf)2 complexes resulted in greatly enhanced oxidation capacity towards one-electron reductants and para-X-substituted-thioanisoles. The reactivities of the Mn(IV)-oxo complexes were markedly enhanced by binding of HOTf, such as a 6.4 × 105-fold increase in the oxygen atom transfer (OAT) reaction (i.e., sulfoxidation). Such a remarkable acceleration in the OAT reaction results from the enhancement of ET from para-X-substituted-thioanisoles to the MnIV(O) complexes as revealed by the unified ET driving force dependence of the rate constants of OAT and ET reactions of [(L)MnIV(O)]2+–(HOTf)2. In contrast, deceleration was observed in the rate of H-atom transfer (HAT) reaction of [(L)MnIV(O)]2+–(HOTf)2 complexes with 1,4-cyclohexadiene as compared with those of the [(L)MnIV(O)]2+ complexes. Thus, the binding of two HOTf molecules to the MnIV(O) moiety resulted in remarkable acceleration of the ET rate when the ET is thermodynamically feasible. When the ET reaction is highly endergonic, the rate of the HAT reaction is decelerated due to the steric effect of the counter anion of HOTf.« less

  11. Use of the ion exchange method for the determination of stability constants of trivalent metal complexes with humic and fulvic acids--part I: Eu3+ and Am3+ complexes in weakly acidic conditions.

    PubMed

    Wenming, Dong; Hongxia, Zhang; Meide, Huang; Zuyi, Tao

    2002-06-01

    The conditional stability constants for tracer concentrations of Eu(III) and Am(III) with a red earth humic acid (REHA), a red earth fulvic acid (REFA) and a fulvic acid from weathered coal (WFA) were determined at pH 5.2-6.4 (such values are similar to those in non-calcareous soils) in the presence of HAc/NaAc or NaNO3 by using the cation exchange method. It was found that 1:1 complexes were predominately formed in weakly acidic conditions. The total exchangeable proton capacities and the degrees of dissociation of these humic substances were determined by using a potentiometric titration method. The key parameters necessary for the experimental determination of the conditional stability constants of metal ions with humic substances in weakly acidic conditions by using the cation exchange method were discussed. The conditional stability constants of 1:1 complexes obtained in this paper were compared with the literature data of Am(III) determined by using the ion exchange method and the solvent extraction method and with the stability constants of 1:1 complexes of UO2(2+) and Th4+ with the same soil humic substances. These results indicate the great stability of bivalent UO2(2+), trivalent Eu3+, Am3+ and tetravalent Th4+ complexes with humic and fulvic acids in weakly acidic conditions. PMID:12102358

  12. Enhanced reduction of Fe(II)EDTA-NO/Fe(III)EDTA in NO(x) scrubber solution using a three-dimensional biofilm-electrode reactor.

    PubMed

    Zhou, Ya; Gao, Lin; Xia, Yin-Feng; Li, Wei

    2012-11-20

    A promising technique called chemical absorption-biological reduction (CABR) integrated approach has been developed recently for the nitrogen oxides (NO(x)) removal from flue gases. The major challenge for this approach is how to enhance the rate of the biological reduction step. To tackle the challenge, a three-dimensional biofilm-electrode reactor (3D-BER) was utilized. This reactor provides not only considerable amount of sites for biofilm, but also many electron donors for bioreduction. Factors affecting the performance of 3D-BER were optimized, including material of the third electrode (graphite), glucose concentration (1000 mg·L(-1)), and volume current density (30.53 A·m(-3) NCC). Experimental results clearly demonstrated that this method significantly promotes the bioreduction rate of Fe(II)EDTA-NO (0.313 mmol·L(-1)·h(-1)) and Fe(III)EDTA (0.564 mmol·L(-1)·h(-1)) simultaneously. Experiments on the mechanism showed that Fe(II)EDTA serves as the primary electron donor in the reduction of Fe(II)EDTA-NO, whereas the reduction of Fe(III)EDTA took advantage of both glucose and electrolysis-generated H(2) as electron donors. High concentration of Fe(II)EDTA-NO or Fe(III)EDTA interferes the bioreduction of the other one. The proposed methodology shows a promising prospect for NO(x) removal from flue gas. PMID:23113866

  13. Chemical cross-linking/mass spectrometry targeting acidic residues in proteins and protein complexes.

    PubMed

    Leitner, Alexander; Joachimiak, Lukasz A; Unverdorben, Pia; Walzthoeni, Thomas; Frydman, Judith; Förster, Friedrich; Aebersold, Ruedi

    2014-07-01

    The study of proteins and protein complexes using chemical cross-linking followed by the MS identification of the cross-linked peptides has found increasingly widespread use in recent years. Thus far, such analyses have used almost exclusively homobifunctional, amine-reactive cross-linking reagents. Here we report the development and application of an orthogonal cross-linking chemistry specific for carboxyl groups. Chemical cross-linking of acidic residues is achieved using homobifunctional dihydrazides as cross-linking reagents and a coupling chemistry at neutral pH that is compatible with the structural integrity of most protein complexes. In addition to cross-links formed through insertion of the dihydrazides with different spacer lengths, zero-length cross-link products are also obtained, thereby providing additional structural information. We demonstrate the application of the reaction and the MS identification of the resulting cross-linked peptides for the chaperonin TRiC/CCT and the 26S proteasome. The results indicate that the targeting of acidic residues for cross-linking provides distance restraints that are complementary and orthogonal to those obtained from lysine cross-linking, thereby expanding the yield of structural information that can be obtained from cross-linking studies and used in hybrid modeling approaches. PMID:24938783

  14. Chemical cross-linking/mass spectrometry targeting acidic residues in proteins and protein complexes

    PubMed Central

    Leitner, Alexander; Joachimiak, Lukasz A.; Unverdorben, Pia; Walzthoeni, Thomas; Frydman, Judith; Förster, Friedrich; Aebersold, Ruedi

    2014-01-01

    The study of proteins and protein complexes using chemical cross-linking followed by the MS identification of the cross-linked peptides has found increasingly widespread use in recent years. Thus far, such analyses have used almost exclusively homobifunctional, amine-reactive cross-linking reagents. Here we report the development and application of an orthogonal cross-linking chemistry specific for carboxyl groups. Chemical cross-linking of acidic residues is achieved using homobifunctional dihydrazides as cross-linking reagents and a coupling chemistry at neutral pH that is compatible with the structural integrity of most protein complexes. In addition to cross-links formed through insertion of the dihydrazides with different spacer lengths, zero-length cross-link products are also obtained, thereby providing additional structural information. We demonstrate the application of the reaction and the MS identification of the resulting cross-linked peptides for the chaperonin TRiC/CCT and the 26S proteasome. The results indicate that the targeting of acidic residues for cross-linking provides distance restraints that are complementary and orthogonal to those obtained from lysine cross-linking, thereby expanding the yield of structural information that can be obtained from cross-linking studies and used in hybrid modeling approaches. PMID:24938783

  15. Detection of nucleic acid-nuclear hormone receptor complexes with mass spectrometry.

    PubMed

    Bich, Claudia; Bovet, Cédric; Rochel, Natacha; Peluso-Iltis, Carole; Panagiotidis, Andreas; Nazabal, Alexis; Moras, Dino; Zenobi, Renato

    2010-04-01

    Nuclear receptors, such as the retinoic acid receptor (RAR) or the 9-cis retinoic acid receptor (RXR), interact not only with their ligands but also with other types of receptors and with DNA. Here, two complementary mass spectrometry (MS) methods were used to study the interactions between retinoic receptors (RXR/RAR) and DNA: non-denaturing nano-electrospray (nanoESI MS), and high-mass matrix-assisted laser desorption ionization (MALDI MS) combined with chemical cross-linking. The RAR x RXR heterodimer was studied in the presence of a specific DNA sequence (DR5), and a specific RAR x RXR x DNA complex was detected with both MS techniques. RAR by itself showed no significant homodimerization. A complex between RAR and the double stranded DR5 was detected with nanoESI. After cross-linking, high-mass MALDI mass spectra showed that the RAR binds the single stranded DR5, and the RAR dimer binds both single and double stranded DR5. Moreover, the MALDI mass spectrum shows a larger RAR dimer signal in the presence of DNA. These results suggest that a gene-regulatory site on DNA can induce quaternary structural changes in a transcription factor such as RAR. PMID:20097575

  16. Associations between free fatty acids, cumulus oocyte complex morphology and ovarian function during in vitro fertilization

    PubMed Central

    Jungheim, Emily S.; Macones, George A.; Odem, Randall R.; Patterson, Bruce W.; Lanzendorf, Susan E.; Ratts, Valerie S.; Moley, Kelle H.

    2011-01-01

    Objective To determine if follicular free fatty acid (FFA) levels are associated with cumulus oocyte complex morphology Design Prospective cohort study Setting University in vitro fertilization (IVF) practice Patients 102 women undergoing IVF Interventions Measurement of FFAs in serum and ovarian follicular fluid Main Outcome Measures Total and specific follicular and serum FFA levels, correlations between follicular and serum FFAs, and associations between follicular FFA levels and markers of oocyte quality including cumulus oocyte complex (COC) morphology Results Predominant follicular fluid and serum FFAs were oleic, palmitic, linoleic and stearic acids. Correlations between follicular and serum FFA concentrations were weak (r=0.252, 0.288, 0.236, 0.309 respectively for specific FFAs; r=0.212 for total FFAs). A receiver operator characteristic curve determined total follicular FFAs ≥ 0.232 µmol/ml distinguished women with lower versus higher percentage COCs with favorable morphology. Women with elevated follicular FFAs (n=31) were more likely to have COCs with poor morphology than others (n=71) (OR 3.3, 95% CI:1.2–9.2). This relationship held after adjusting for potential confounders including age, BMI, endometriosis and amount of gonadotropin administered (β=1.2; OR 3.4, 95% CI:1.1–10.4). Conclusions Elevated follicular FFA levels are associated with poor COC morphology. Further work is needed to determine what factors influence follicular FFA levels and if these factors impact fertility. PMID:21353671

  17. Sm(II)-Mediated Electron Transfer to Carboxylic Acid Derivatives: Development of Complexity-Generating Cascades.

    PubMed

    Just-Baringo, Xavier; Procter, David J

    2015-05-19

    exploited productively in efficient new processes. First, we have used internal directing groups in substrates to "switch on" productive ET to esters and amides and have exploited such an approach in tag-removal cyclization processes that deliver molecular scaffolds of significance in biology and materials science. Second, we have exploited external ligands to facilitate ET to carboxylic acid derivatives and have applied the strategy in telescoped reaction sequences. Finally, we have employed follow-up cyclizations with alkenes, alkynes, and allenes to intercept radical anion intermediates formed along the reaction path and have employed this strategy in complexity-generating cascade approaches to biologically significant molecular architectures. From our studies, it is now clear that Sm(II)-mediated ET to carboxylic acid derivatives constitutes a general strategy for inverting the polarity of the carbonyl, allowing nucleophilic carbon-centered radicals to be formed and exploited in novel chemical processes. PMID:25871998

  18. Inhibitory effects of combinations of oxytetracycline, dimethyl sulfoxide, and EDTA-tromethamine on Escherichia coli.

    PubMed

    Wooley, R E; Gilbert, J P; Shotts, E B

    1981-11-01

    Antibacterial activity against Escherichia coli was obtained with subminimal inhibitory concentrations of oxytetracycline (OTC) and EDTA-tromethamine. Inhibitory effects were not observed using combinations of dimethyl sulfoxide and OTC or dimethyl sulfoxide and EDTA-tromethamine. Neither EDTA-tromethamine nor OTC used alone was capable of the same degree of inhibition. Using a 2-dimensional Microtiter checkerboard technique, the inhibitory activity of these combinations was studied and isobolograms were plotted. A synergistic effect was seen with combinations of OTC and EDTA-tromethamine. Kinetic studies of microbial death, using subminimal inhibitory concentrations of these agents, confirmed these findings. PMID:6802044

  19. Self-assembly and cytotoxicity study of waterwheel-like dinuclear metal complexes: the first metal complexes appended with multiple free hydroxamic acid groups.

    PubMed

    Wang, Wen-Hua; Liu, Wei-Sheng; Wang, Ya-Wen; Li, Yang; Zheng, Li-Fang; Wang, Da-Qi

    2007-02-01

    Two waterwheel-like dinuclear complexes [M(2)(PHA)(4)(H(2)O)(2)] (M = Cu(II) (1), Zn(II) (2); HPHA = phthal-hydroxamic acid) appended with four free hydroxamic acid groups, namely, free hydroxamic acid metal complexes (FHAMCs) have been synthesized and characterized. The crystal structure of complex 1 was determined by single crystal X-ray diffraction, which adopts the paddlewheel motif with four bidentate carboxylate ligands joining two Cu(II) ions. The relative cytotoxicities of compounds 1 and 2 against SMMC-7721 and HO-8910 cell lines are similar and more predominant than HPHA (IC(50): Cu(II)>Zn(II)>HPHA). The synergic effect of the bound water molecules, multiple free hydroxamic acid groups and dimetal active sites with bridging carboxylate may have significant impacts on their pharmacological activity. As the prototype for a new class of hydroxamic acid derivatives, the self-assembly of FHAMCs presents a promising new strategy in designing multiple hydroxamic acids with remarkable bioactivities. PMID:17125839

  20. Depolarization-induced release of amino acids from the vestibular nuclear complex.

    PubMed

    Godfrey, Donald A; Sun, Yizhe; Frisch, Christopher; Godfrey, Matthew A; Rubin, Allan M

    2012-04-01

    There is evidence from immunohistochemistry, quantitative microchemistry, and pharmacology for several amino acids as neurotransmitters in the vestibular nuclear complex (VNC), including glutamate, γ-aminobutyrate (GABA), and glycine. However, evidence from measurements of release has been limited. The purpose of this study was to measure depolarization-stimulated calcium-dependent release of amino acids from the VNC in brain slices. Coronal slices containing predominantly the VNC were prepared from rats and perfused with artificial cerebrospinal fluid (ACSF) in an interface chamber. Fluid was collected from the chamber just downstream from the VNC using a microsiphon. Depolarization was induced by 50 mM potassium in either control calcium and magnesium concentrations or reduced calcium and elevated magnesium. Amino acid concentrations in effluent fluid were measured by high performance liquid chromatography. Glutamate release increased fivefold during depolarization in control calcium concentration and twofold in low calcium/high magnesium. These same ratios were 6 and 1.5 for GABA, 2 and 1.3 for glycine, and 2 and 1.5 for aspartate. Differences between release in control and low calcium/high magnesium ACSF were statistically significant for glutamate, GABA, and glycine. Glutamine release decreased during and after depolarization, and taurine release slowly increased. No evidence for calcium-dependent release was found for serine, glutamine, alanine, threonine, arginine, taurine, or tyrosine. Our results support glutamate and GABA as major neurotransmitters in the VNC. They also support glycine as a neurotransmitter and some function for taurine. PMID:22147284

  1. Amino acid-dependent NPRL2 interaction with Raptor determines mTOR Complex 1 activation.

    PubMed

    Kwak, Sang Su; Kang, Kyung Hwa; Kim, Seyun; Lee, Seoeun; Lee, Jeung-Hoon; Kim, Jin Woo; Byun, Boohyeong; Meadows, Gary G; Joe, Cheol O

    2016-02-01

    We assign a new function to a tumor suppressor NPRL2 that activates the mTOR complex 1 (mTORC1) activity. The positive regulation of mTORC1 activity by NPRL2 is mediated through NPRL2 interaction with Raptor. While NPRL2 interacts with Rag GTPases, RagD in particular, to interfere with mTORC1 activity in amino acid scarcity, NPRL2 interacts with Raptor in amino acid sufficiency to activate mTORC1. A reciprocal relationship exists between NPRL2 binding to Rag GTPases and Raptor. NPRL2 majorly locates in the lysosomal membranes and has a higher binding affinity to the dominant negative mutant heterodimer of RagA(GDP)/RagD(GTP) that inactivates mTORC1. However, the binding affinity of NPRL2 with Raptor is much less pronounced in cells expressing the dominant negative mutant heterodimer of RagA(GDP)/RagD(GTP) than in cells expressing the dominant positive mutant heterodimer, RagA(GTP)/RagD(GDP). The positive effect of NPRL2 on TORC1 pathway was also evidenced in Drosophila animal model. Here, we propose a 'seesaw' model in which the interactive behavior of NPRL2 with Raptor determines mTORC1 activation by amino acid signaling in animal cells. PMID:26582740

  2. Complex formation equilibria of binary and ternary complexes involving 3,3-bis(1-methylimidazol-2yl)propionic acid and bio-relevant ligands as 1-aminocyclopropane carboxylic acid with reference to plant hormone

    NASA Astrophysics Data System (ADS)

    Shoukry, Mohamed M.; Hassan, Safaa S.

    2014-01-01

    The formation equilibria for the binary complexes of Cu(II) with 1-aminocyclopropane carboxylic acid (ACC) and 3,3-bis(1-methylimidazol-2-yl)propionic acid (BIMP) were investigated. ACC and BIMP form the complexes 1 1 0, 1 2 0 and 1 1 -1. The ternary complexes of Cu(II) with BIMP and biorelevant ligands as some selected amino acids, peptides and DNA constituents are formed in a stepwise mechanism. The stability constants of the complexes formed were determined and their distribution diagrams were evaluated. The kinetics of hydrolysis of glycine methyl ester in presence of [Cu(BIMP)]+ was investigated by pH-stat technique and the mechanism was discussed.

  3. Interaction of antitumor alpha-lactalbumin-oleic acid complexes with artificial and natural membranes.

    PubMed

    Zherelova, Olga M; Kataev, Anatoly A; Grishchenko, Valery M; Knyazeva, Ekaterina L; Permyakov, Sergei E; Permyakov, Eugene A

    2009-06-01

    The specific complexes of human alpha-lactalbumin (alpha-LA) with oleic acid (OA), HAMLET and LA-OA-17 (OA-complexes), possess cytotoxic activity against tumor cells but the mechanism of their cell penetration remains unclear. To explore the molecular mechanisms underlying interaction of the OA-complexes with the cell membrane, their interactions with small unilamellar dipalmitoylphosphatidylcholine (DPPC) vesicles and electroexcitable plasma membrane of internodal native and perfused cells of the green alga Chara corallina have been studied. The fractionation (Sephadex G-200) of mixtures of the OA-complexes with the vesicles shows that OA-binding increases the affinity of alpha-LA to DPPC vesicles. Calcium association decreases protein affinity to the vesicles; the effect being less pronounced for LA-OA-17. The voltage clamp technique studies show that LA-OA-17, HAMLET, and their constituents produce different modifying effects on the plasmalemmal ionic channels of the Chara corallina cells. The irreversible binding of OA-complexes to the plasmalemma is accompanied by changes in the activation-inactivation kinetics of developing integral transmembrane currents, suppression of the Ca(2+) current and Ca(2+)-activated Cl(-) current, and by increase in the nonspecific K(+) leakage currents. The latter reflects development of nonselective permeability of the plasma membrane. The HAMLET-induced effects on the plasmalemmal currents are less pronounced and potentiated by LA-OA-17. The control experiments with OA and intact alpha-LA show their qualitatively different and much less pronounced effects on the transmembrane ionic currents. Thus, the modification of alpha-LA by OA results in an increase in the protein association with the model lipid bilayer and in drastic irreversible changes in permeability of several types of the plasmalemmal ionic channels. PMID:19588235

  4. Evidence for Physical Association of Mitochondrial Fatty Acid Oxidation and Oxidative Phosphorylation Complexes

    PubMed Central

    Wang, Yudong; Mohsen, Al-Walid; Mihalik, Stephanie J.; Goetzman, Eric S.; Vockley, Jerry

    2010-01-01

    Fatty acid β-oxidation (FAO) and oxidative phosphorylation (OXPHOS) are key pathways involved in cellular energetics. Reducing equivalents from FAO enter OXPHOS at the level of complexes I and III. Genetic disorders of FAO and OXPHOS are among the most frequent inborn errors of metabolism. Patients with deficiencies of either FAO or OXPHOS often show clinical and/or biochemical findings indicative of a disorder of the other pathway. In this study, the physical and functional interactions between these pathways were examined. Extracts of isolated rat liver mitochondria were subjected to blue native polyacrylamide gel electrophoresis (BNGE) to separate OXPHOS complexes and supercomplexes followed by Western blotting using antisera to various FAO enzymes. Extracts were also subjected to sucrose density centrifugation and fractions analyzed by BNGE or enzymatic assays. Several FAO enzymes co-migrated with OXPHOS supercomplexes in different patterns in the gels. When palmitoyl-CoA was added to the sucrose gradient fractions containing OXPHOS supercomplexes in the presence of potassium cyanide, cytochrome c was reduced. Cytochrome c reduction was completely blocked by myxothiazol (a complex III inhibitor) and 3-mercaptopropionate (an inhibitor of the first step of FAO), but was only partially inhibited by rotenone (a complex I inhibitor). Although palmitoyl-CoA and octanoyl-CoA provided reducing equivalents to OXPHOS-containing supercomplex fractions, no accumulation of their intermediates was detected. In contrast, short branched acyl-CoA substrates were not metabolized by OXPHOS-containing supercomplex fractions. These data provide evidence of a multifunctional FAO complex within mitochondria that is physically associated with OXPHOS supercomplexes and promotes metabolic channeling. PMID:20663895

  5. Spectroscopic studies of R(+)-α-lipoic acid--cyclodextrin complexes.

    PubMed

    Ikuta, Naoko; Tanaka, Akira; Otsubo, Ayako; Ogawa, Noriko; Yamamoto, Hiromitsu; Mizukami, Tomoyuki; Arai, Shoji; Okuno, Masayuki; Terao, Keiji; Matsugo, Seiichi

    2014-01-01

    α-Lipoic acid (ALA) has a chiral center at the C6 position, and exists as two enantiomers, R(+)-ALA (RALA) and S(-)-ALA (SALA). RALA is naturally occurring, and is a cofactor for mitochondrial enzymes, therefore playing a major role in energy metabolism. However, RALA cannot be used for pharmaceuticals or nutraceuticals because it readily polymerizes via a 1,2-dithiolane ring-opening when exposed to light or heat. So, it is highly desired to find out the method to stabilize RALA. The purpose of this study is to provide the spectroscopic information of stabilized RALA and SALA through complexation with cyclodextrins (CDs), α-CD, β-CD and γ-CD and to examine the physical characteristics of the resultant complexes in the solid state. The RALA-CD structures were elucidated based on the micro fourier transform infrared (FT-IR) and Raman analyses. The FT-IR results showed that the C=O stretching vibration of RALA appeared at 1717 cm⁻¹ and then shifted on formation of the RALA-CD complexes. The Raman spectra showed that the S-S and C-S stretching vibrations for RALA at 511 cm⁻¹ (S-S), 631 cm⁻¹ (C-S) and 675 cm⁻¹ (C-S) drastically weakened and almost disappeared upon complexation with CDs. Several peaks indicative of O-H vibrations also shifted or changed in intensity. These results indicate that RALA and CDs form host-guest complexes by interacting with one another. PMID:25387076

  6. Deciphering the binding patterns and conformation changes upon the bovine serum albumin-rosmarinic acid complex.

    PubMed

    Peng, Xin; Wang, Xiangchao; Qi, Wei; Huang, Renliang; Su, Rongxin; He, Zhimin

    2015-08-01

    Rosmarinic acid (RA) is an importantly and naturally occurring polyphenol from plants of the mint family with potent biological activities. Here, the in vitro interaction of RA with bovine serum albumin (BSA) has been investigated using various biophysical approaches as well as molecular modeling methods, to ascertain its binding mechanism and conformational changes. The fluorescence results demonstrated that the fluorescence quenching of BSA by RA was mainly the result of the formation of a ground state BSA-RA complex, and BSA had one high affinity RA binding site with a binding constant of 4.18 × 10(4) mol L(-1) at 298 K. Analysis of thermodynamic parameters revealed that hydrophobic and hydrogen bond interactions were the dominant intermolecular force in the complex formation. The primary binding site of RA in BSA (site I) had been identified by site marker competitive experiments. The distance between RA and the tryptophan residue of BSA was evaluated at 3.12 nm based on Förster's theory of non-radiation energy transfer. The UV-vis absorption, synchronous fluorescence, three-dimensional fluorescence, 8-anilino-1-naphthalenesulfonic acid (ANS) fluorescence, circular dichroism (CD), and Fourier transform infrared (FT-IR) spectra confirmed that the conformation and structure of BSA were altered in the presence of RA. Moreover, the nuclear magnetic spectroscopy showed that the aromatic groups of RA took part in the binding reaction during the BSA-RA complexation. In addition, the molecular picture of the interaction mechanism between BSA and RA at the atomic level was well examined by molecular docking and dynamics studies. In brief, RA can bind to BSA with noncovalent bonds in a relatively stable way, and these findings will be beneficial to the functional food research of RA. PMID:26146359

  7. Cytotoxicity of bovine α-lactalbumin: oleic acid complexes correlates with the disruption of lipid membranes.

    PubMed

    Wen, Hanzhen; Glomm, Wilhelm R; Halskau, Oyvind

    2013-11-01

    HAMLET/BAMLET (Human/Bovine α-Lactalbumin Made Lethal to Tumors) is a tumoricidal substance composed of partially unfolded human/bovine α-lactalbumin (HLA/BLA) and several oleic acid (OA) molecules. The HAMLET mechanism of interaction involves an insufficiently understood effect on the membrane or its embedded components. We examined the effect of BLAOA (bovine α-lactalbumin complexed with oleic acid, a HAMLET-like substance) and its individual components on cells and artificial lipid membranes using viability staining and metabolic dyes, fluorescence spectroscopy, leakage integrity assays and microscopy. Our results show a dose-dependency of OA used to prepare BLAOA on its ability to induce tumor cell death, and a correlation between leakage and cell death. BLAOA incorporates into the membrane, tightens the lipid packing and lowers their solvent accessibility. Fluorescence imaging reveals that giant unilamellar vesicles (GUVs) develop blebs and eventually collapse upon exposure to BLAOA, indicating that the lipid packing reorganization can translate into observable morphological effects. These effects are observed to be local in GUVs, and a tightly packed and solvent-shielded lipid environment is associated with leakage and GUV disruption. Furthermore, the effects of BLAOA on membrane are pH dependent, with an optimum of activity on artificial membranes near neutral pHs. While BLA alone is effective at membrane disruption at acidic pHs, OA is ineffective in a pH range of 4.5 to 9.1. Taken together, this supports a model where the lipid, fatty acid and protein components enhance each other's ability to affect the overall integrity of the membrane. PMID:23916586

  8. Inhibition of the fungal fatty acid synthase type I multienzyme complex

    PubMed Central

    Johansson, Patrik; Wiltschi, Birgit; Kumari, Preeti; Kessler, Brigitte; Vonrhein, Clemens; Vonck, Janet; Oesterhelt, Dieter; Grininger, Martin

    2008-01-01

    Fatty acids are among the major building blocks of living cells, making lipid biosynthesis a potent target for compounds with antibiotic or antineoplastic properties. We present the crystal structure of the 2.6-MDa Saccharomyces cerevisiae fatty acid synthase (FAS) multienzyme in complex with the antibiotic cerulenin, representing, to our knowledge, the first structure of an inhibited fatty acid megasynthase. Cerulenin attacks the FAS ketoacyl synthase (KS) domain, forming a covalent bond to the active site cysteine C1305. The inhibitor binding causes two significant conformational changes of the enzyme. First, phenylalanine F1646, shielding the active site, flips and allows access to the nucleophilic cysteine. Second, methionine M1251, placed in the center of the acyl-binding tunnel, rotates and unlocks the inner part of the fatty acid binding cavity. The importance of the rotational movement of the gatekeeping M1251 side chain is reflected by the cerulenin resistance and the changed product spectrum reported for S. cerevisiae strains mutated in the adjacent glycine G1250. Platensimycin and thiolactomycin are two other potent inhibitors of KSs. However, in contrast to cerulenin, they show selectivity toward the prokaryotic FAS system. Because the flipped F1646 characterizes the catalytic state accessible for platensimycin and thiolactomycin binding, we superimposed structures of inhibited bacterial enzymes onto the S. cerevisiae FAS model. Although almost all side chains involved in inhibitor binding are conserved in the FAS multienzyme, a different conformation of the loop K1413–K1423 of the KS domain might explain the observed low antifungal properties of platensimycin and thiolactomycin. PMID:18725634

  9. Lactic acid bacteria contribution to gut microbiota complexity: lights and shadows

    PubMed Central

    Pessione, Enrica

    2012-01-01

    Lactic Acid Bacteria (LAB) are ancient organisms that cannot biosynthesize functional cytochromes, and cannot get ATP from respiration. Besides sugar fermentation, they evolved electrogenic decarboxylations and ATP-forming deiminations. The right balance between sugar fermentation and decarboxylation/deimination ensures buffered environments thus enabling LAB to survive in human gastric trait and colonize gut. A complex molecular cross-talk between LAB and host exists. LAB moonlight proteins are made in response to gut stimuli and promote bacterial adhesion to mucosa and stimulate immune cells. Similarly, when LAB are present, human enterocytes activate specific gene expression of specific genes only. Furthermore, LAB antagonistic relationships with other microorganisms constitute the basis for their anti-infective role. Histamine and tyramine are LAB bioactive catabolites that act on the CNS, causing hypertension and allergies. Nevertheless, some LAB biosynthesize both gamma-amino-butyrate (GABA), that has relaxing effect on gut smooth muscles, and beta-phenylethylamine, that controls satiety and mood. Since LAB have reduced amino acid biosynthetic abilities, they developed a sophisticated proteolytic system, that is also involved in antihypertensive and opiod peptide generation from milk proteins. Short-chain fatty acids are glycolytic and phosphoketolase end-products, regulating epithelial cell proliferation and differentiation. Nevertheless, they constitute a supplementary energy source for the host, causing weight gain. Human metabolism can also be affected by anabolic LAB products such as conjugated linoleic acids (CLA). Some CLA isomers reduce cancer cell viability and ameliorate insulin resistance, while others lower the HDL/LDL ratio and modify eicosanoid production, with detrimental health effects. A further appreciated LAB feature is the ability to fix selenium into seleno-cysteine. Thus, opening interesting perspectives for their utilization as

  10. Covalent grafting of copper amino acid complexes onto chloropropylated silica gel—an FT-IR study

    NASA Astrophysics Data System (ADS)

    Jakab, N. I.; Hernadi, K.; Kiss, J. T.; Pálinkó, I.

    2005-06-01

    Cu(amino acid) complexes were immobilised on silica gel by covalent anchoring. The amino acids were L-histidine and L-tyrosine and their BOC—( tert-butoxycarbonyl) or methyl ester protected derivatives. To gain control over the synthesis the appropriately protected amino acid was reacted with chloropropylated silica gel first. This modified material as is, or after deprotecting the anchored amino acids, was used in further steps of building the immobilised Cu(II) complex. The covalently grafted complexes were studied by FT-IR spectroscopy and computer modelling. Materials containing protected histidine ligands showed catalase activity (decomposition of H 2O 2), those containing protected or unprotected tyrosine ligands displayed tyrosinase activity (the decomposed H 2O 2 oxidised the tyrosine skeleton to a quinoidal structure).

  11. K(3)EDTA Vacuum Tubes Validation for Routine Hematological Testing.

    PubMed

    Lima-Oliveira, Gabriel; Lippi, Giuseppe; Salvagno, Gian Luca; Montagnana, Martina; Poli, Giovanni; Solero, Giovanni Pietro; Picheth, Geraldo; Guidi, Gian Cesare

    2012-01-01

    Background and Objective. Some in vitro diagnostic devices (e.g, blood collection vacuum tubes and syringes for blood analyses) are not validated before the quality laboratory managers decide to start using or to change the brand. Frequently, the laboratory or hospital managers select the vacuum tubes for blood collection based on cost considerations or on relevance of a brand. The aim of this study was to validate two dry K(3)EDTA vacuum tubes of different brands for routine hematological testing. Methods. Blood specimens from 100 volunteers in two different K(3)EDTA vacuum tubes were collected by a single, expert phlebotomist. The routine hematological testing was done on Advia 2120i hematology system. The significance of the differences between samples was assessed by paired Student's t-test after checking for normality. The level of statistical significance was set at P < 0.05. Results and Conclusions. Different brand's tubes evaluated can represent a clinically relevant source of variations only on mean platelet volume (MPV) and platelet distribution width (PDW). Basically, our validation will permit the laboratory or hospital managers to select the brand's vacuum tubes validated according to him/her technical or economical reasons for routine hematological tests. PMID:22888448

  12. K3EDTA Vacuum Tubes Validation for Routine Hematological Testing

    PubMed Central

    Lima-Oliveira, Gabriel; Lippi, Giuseppe; Salvagno, Gian Luca; Montagnana, Martina; Poli, Giovanni; Solero, Giovanni Pietro; Picheth, Geraldo; Guidi, Gian Cesare

    2012-01-01

    Background and Objective. Some in vitro diagnostic devices (e.g, blood collection vacuum tubes and syringes for blood analyses) are not validated before the quality laboratory managers decide to start using or to change the brand. Frequently, the laboratory or hospital managers select the vacuum tubes for blood collection based on cost considerations or on relevance of a brand. The aim of this study was to validate two dry K3EDTA vacuum tubes of different brands for routine hematological testing. Methods. Blood specimens from 100 volunteers in two different K3EDTA vacuum tubes were collected by a single, expert phlebotomist. The routine hematological testing was done on Advia 2120i hematology system. The significance of the differences between samples was assessed by paired Student's t-test after checking for normality. The level of statistical significance was set at P < 0.05. Results and Conclusions. Different brand's tubes evaluated can represent a clinically relevant source of variations only on mean platelet volume (MPV) and platelet distribution width (PDW). Basically, our validation will permit the laboratory or hospital managers to select the brand's vacuum tubes validated according to him/her technical or economical reasons for routine hematological tests. PMID:22888448

  13. Synthesis, structural characterization and biological studies of some nalidixic acid-metal complexes: Metalloantibiotic complexes of some divalent and trivalent metal ions

    NASA Astrophysics Data System (ADS)

    Al-Khodir, Fatima A. I.; Refat, Moamen S.

    2015-08-01

    This article describes the synthesis, characterization, computational and biological assessments of some divalent and trivalent metal (Ca(II), Fe(III), Pd(II) and Au(III)) complexes of nalidixic acid (nixH). The structures of these complexes were assigned using elemental analyses and spectral measurements e.g., IR, Raman, 1H NMR, 13C NMR and electronic techniques. These results indicated that, nalidixic acid reacts as a bidentate ligand bound to the metal ion through the oxygen atoms of carbonyl and carboxylate groups. The molar conductance measurements of the complexes in DMSO correspond to be non-electrolyte nature. Thus, these complexes may be formulated as [Ca(nix)(Cl)(H2O)3]. H2O, [Fe(nix)(Cl)2(H2O)2]·3H2O, [Pd(nix)(Cl)(H2O)] and [Au(nix)(Cl)2]. Base on the Coats-Redfern and Horowitz-Metzeger methods, the kinetic thermodynamic parameters (E∗, ΔS∗, ΔH∗ and ΔG∗) of the thermal decomposition reactions have been calculated from thermogravimetric curves of TG and DTG. The nano-scale range of the nalidixic acid complexes have been discussed using X-ray powder diffraction (XRD), scanning electron microscope (SEM) and transmission electron microscopy (TEM) analyzer. The computational studies for the synthesized complexes have been estimated.

  14. New copper(II) complexes with dopamine hydrochloride and vanillymandelic acid: Spectroscopic and thermal characterization

    NASA Astrophysics Data System (ADS)

    Mohamed, Gehad G.; Nour El-Dien, F. A.; El-Nahas, R. G.

    2011-10-01

    The dopamine derivatives participate in the regulation of wide variety of physiological functions in the human body and in medication life. Increase and/or decrease in the concentration of dopamine in human body reflect an indication for diseases such as Schizophrenia and/or Parkinson diseases. The Cu(II) chelates with coupled products of dopamine hydrochloride (DO.HCl) and vanillymandelic acid (VMA) with 4-aminoantipyrine (4-AAP) are prepared and characterized. Different physico-chemical techniques namely IR, magnetic and UV-vis spectra are used to investigate the structure of these chelates. Cu(II) forms 1:1 (Cu:DO) and 1:2 (Cu:VMA) chelates. DO behave as a uninegative tridentate ligand in binding to the Cu(II) ion while VMA behaves as a uninegative bidentate ligand. IR spectra show that the DO is coordinated to the Cu(II) ion in a tridentate manner with ONO donor sites of the phenolic- OH, -NH and carbonyl- O, while VMA is coordinated with OO donor sites of the phenolic- OH and -NH. Magnetic moment measurements reveal the presence of Cu(II) chelates in octahedral and square planar geometries with DO and VMA, respectively. The thermal decomposition of Cu(II) complexes is studied using thermogravimetric (TG) and differential thermal analysis (DTA) techniques. The activation thermodynamic parameters, such as, energy of activation, enthalpy, entropy and free energy change of the complexes are evaluated and the relative thermal stability of the complexes are discussed.

  15. Enantioselective Hydrolysis of Amino Acid Esters Promoted by Bis(β-cyclodextrin) Copper Complexes

    NASA Astrophysics Data System (ADS)

    Xue, Shan-Shan; Zhao, Meng; Ke, Zhuo-Feng; Cheng, Bei-Chen; Su, Hua; Cao, Qian; Cao, Zhen-Kun; Wang, Jun; Ji, Liang-Nian; Mao, Zong-Wan

    2016-02-01

    It is challenging to create artificial catalysts that approach enzymes with regard to catalytic efficiency and selectivity. The enantioselective catalysis ranks the privileged characteristic of enzymatic transformations. Here, we report two pyridine-linked bis(β-cyclodextrin) (bisCD) copper(II) complexes that enantioselectively hydrolyse chiral esters. Hydrolytic kinetic resolution of three pairs of amino acid ester enantiomers (S1-S3) at neutral pH indicated that the “back-to-back” bisCD complex CuL1 favoured higher catalytic efficiency and more pronounced enantioselectivity than the “face-to-face” complex CuL2. The best enantioselectivity was observed for N-Boc-phenylalanine 4-nitrophenyl ester (S2) enantiomers promoted by CuL1, which exhibited an enantiomer selectivity of 15.7. We observed preferential hydrolysis of L-S2 by CuL1, even in racemic S2, through chiral high-performance liquid chromatography (HPLC). We demonstrated that the enantioselective hydrolysis was related to the cooperative roles of the intramolecular flanking chiral CD cavities with the coordinated copper ion, according to the results of electrospray ionization mass spectrometry (ESI-MS), inhibition experiments, rotating-frame nuclear Overhauser effect spectroscopy (ROESY), and theoretical calculations. Although the catalytic parameters lag behind the level of enzymatic transformation, this study confirms the cooperative effect of the first and second coordination spheres of artificial catalysts in enantioselectivity and provides hints that may guide future explorations of enzyme mimics.

  16. Bis(allyl)-ruthenium(iv) complexes with phosphinous acid ligands as catalysts for nitrile hydration reactions.

    PubMed

    Tomás-Mendivil, Eder; Francos, Javier; González-Fernández, Rebeca; González-Liste, Pedro J; Borge, Javier; Cadierno, Victorio

    2016-09-14

    Several mononuclear ruthenium(iv) complexes with phosphinous acid ligands [RuCl2(η(3):η(3)-C10H16)(PR2OH)] have been synthesized (78-86% yield) by treatment of the dimeric precursor [{RuCl(μ-Cl)(η(3):η(3)-C10H16)}2] (C10H16 = 2,7-dimethylocta-2,6-diene-1,8-diyl) with 2 equivalents of different aromatic, heteroaromatic and aliphatic secondary phosphine oxides R2P([double bond, length as m-dash]O)H. The compounds [RuCl2(η(3):η(3)-C10H16)(PR2OH)] could also be prepared, in similar yields, by hydrolysis of the P-Cl bond in the corresponding chlorophosphine-Ru(iv) derivatives [RuCl2(η(3):η(3)-C10H16)(PR2Cl)]. In addition to NMR and IR data, the X-ray crystal structures of representative examples are discussed. Moreover, the catalytic behaviour of complexes [RuCl2(η(3):η(3)-C10H16)(PR2OH)] has been investigated for the selective hydration of organonitriles in water. The best results were achieved with the complex [RuCl2(η(3):η(3)-C10H16)(PMe2OH)], which proved to be active under mild conditions (60 °C), with low metal loadings (1 mol%), and showing good functional group tolerance. PMID:27510460

  17. Pickering Emulsion Gels Prepared by Hydrogen-Bonded Zein/Tannic Acid Complex Colloidal Particles.

    PubMed

    Zou, Yuan; Guo, Jian; Yin, Shou-Wei; Wang, Jin-Mei; Yang, Xiao-Quan

    2015-08-26

    Food-grade colloidal particles and complexes, which are formed via modulation of the noncovalent interactions between macromolecules and natural small molecules, can be developed as novel functional ingredients in a safe and sustainable way. For this study was prepared a novel zein/tannic acid (TA) complex colloidal particle (ZTP) based on the hydrogen-bonding interaction between zein and TA in aqueous ethanol solution by using a simple antisolvent approach. Pickering emulsion gels with high oil volume fraction (φ(oil) > 50%) were successfully fabricated via one-step homogenization. Circular dichroism (CD) and small-angle X-ray scattering (SAXS) measurements, which were used to characterize the structure of zein/TA complexes in ethanol solution, clearly showed that TA binding generated a conformational change of zein without altering their supramolecular structure at pH 5.0 and intermediate TA concentrations. Consequently, the resultant ZTP had tuned near neutral wettability (θ(ow) ∼ 86°) and enhanced interfacial reactivity, but without significantly decreased surface charge. These allowed the ZTP to stabilize the oil droplets and further triggered cross-linking to form a continuous network among and around the oil droplets and protein particles, leading to the formation of stable Pickering emulsion gels. Layer-by-layer (LbL) interfacial architecture on the oil-water surface of the droplets was observed, which implied a possibility to fabricate hierarchical interface microstructure via modulation of the noncovalent interaction between hydrophobic protein and natural polyphenol. PMID:26226053

  18. Complexes between ovalbumin nanoparticles and linoleic acid: Stoichiometric, kinetic and thermodynamic aspects.

    PubMed

    Sponton, Osvaldo E; Perez, Adrián A; Carrara, Carlos R; Santiago, Liliana G

    2016-11-15

    Stoichiometric, kinetic and thermodynamic aspects of complex formation between heat-induced aggregates of ovalbumin (ovalbumin nanoparticles, OVAn) and linoleic acid (LA) were evaluated. Extrinsic fluorescence data were fitted to modified Scatchard model yielding the following results: n: 49±2 LA molecules bound per OVA monomer unit and Ka: 9.80±2.53×10(5)M. Kinetic and thermodynamic properties were analyzed by turbidity measurements at different LA/OVA monomer molar ratios (21.5-172) and temperatures (20-40°C). An adsorption approach was used and a pseudo-second-order kinetics was found for LA-OVAn complex formation. This adsorption process took place within 1h. Thermodynamic parameters indicated that LA adsorption on OVAn was a spontaneous, endothermic and entropically-driven process, highlighting the hydrophobic nature of the LA and OVAn interaction. Finally, Atomic Force Microscopy imaging revealed that both OVAn and LA-OVAn complexes have a roughly rounded form with size lower than 100nm. PMID:27283701

  19. Enantioselective Hydrolysis of Amino Acid Esters Promoted by Bis(β-cyclodextrin) Copper Complexes.

    PubMed

    Xue, Shan-Shan; Zhao, Meng; Ke, Zhuo-Feng; Cheng, Bei-Chen; Su, Hua; Cao, Qian; Cao, Zhen-Kun; Wang, Jun; Ji, Liang-Nian; Mao, Zong-Wan

    2016-01-01

    It is challenging to create artificial catalysts that approach enzymes with regard to catalytic efficiency and selectivity. The enantioselective catalysis ranks the privileged characteristic of enzymatic transformations. Here, we report two pyridine-linked bis(β-cyclodextrin) (bisCD) copper(II) complexes that enantioselectively hydrolyse chiral esters. Hydrolytic kinetic resolution of three pairs of amino acid ester enantiomers (S1-S3) at neutral pH indicated that the "back-to-back" bisCD complex CuL(1) favoured higher catalytic efficiency and more pronounced enantioselectivity than the "face-to-face" complex CuL(2). The best enantioselectivity was observed for N-Boc-phenylalanine 4-nitrophenyl ester (S2) enantiomers promoted by CuL(1), which exhibited an enantiomer selectivity of 15.7. We observed preferential hydrolysis of L-S2 by CuL(1), even in racemic S2, through chiral high-performance liquid chromatography (HPLC). We demonstrated that the enantioselective hydrolysis was related to the cooperative roles of the intramolecular flanking chiral CD cavities with the coordinated copper ion, according to the results of electrospray ionization mass spectrometry (ESI-MS), inhibition experiments, rotating-frame nuclear Overhauser effect spectroscopy (ROESY), and theoretical calculations. Although the catalytic parameters lag behind the level of enzymatic transformation, this study confirms the cooperative effect of the first and second coordination spheres of artificial catalysts in enantioselectivity and provides hints that may guide future explorations of enzyme mimics. PMID:26916830

  20. Structural basis of intramitochondrial phosphatidic acid transport mediated by Ups1-Mdm35 complex

    PubMed Central

    Yu, Fang; He, Fangyuan; Yao, Hongyan; Wang, Chengyuan; Wang, Jianchuan; Li, Jianxu; Qi, Xiaofeng; Xue, Hongwei; Ding, Jianping; Zhang, Peng

    2015-01-01

    Ups1 forms a complex with Mdm35 and is critical for the transport of phosphatidic acid (PA) from the mitochondrial outer membrane to the inner membrane. We report the crystal structure of the Ups1-Mdm35-PA complex and the functional characterization of Ups1-Mdm35 in PA binding and transfer. Ups1 features a barrel-like structure consisting of an antiparallel β-sheet and three α-helices. Mdm35 adopts a three-helical clamp-like structure to wrap around Ups1 to form a stable complex. The β-sheet and α-helices of Ups1 form a long tunnel-like pocket to accommodate the substrate PA, and a short helix α2 acts as a lid to cover the pocket. The hydrophobic residues lining the pocket and helix α2 are critical for PA binding and transfer. In addition, a hydrophilic patch on the surface of Ups1 near the PA phosphate-binding site also plays an important role in the function of Ups1-Mdm35. Our study reveals the molecular basis of the function of Ups1-Mdm35 and sheds new light on the mechanism of intramitochondrial phospholipid transport by the MSF1/PRELI family proteins. PMID:26071601

  1. Complexation of Hg (II) ions with humic acids of tundra soils

    NASA Astrophysics Data System (ADS)

    Vasilevich, Roman

    2013-04-01

    Humic acids (HA) play an important role in processes of heavy metals migration, controlling their geochemical streams in environment. Accumulative and detoxification abilities of HA to heavy metals are realized by means of formation of steady complexes salycylate and pyrocatechin types. Modern researches show that HA of the Arctic and Subarctic areas are poorly enriched by aromatic frames, so and metalbinding centres. The work purpose is to study interaction mechanisms of Hg (II) ions with HA and to define tread possibilities of a tundra soils humic acids. It is established that binding ability of Hg (II) ions depends on concentration of an element, on quantity of functional groups in peripheral and nuclear parts of HA molecule as well as on a solution pH. coomplexation proceeds at pH 2.5-3.5 efficiently. On the basis of kinetic models it is shown that HA interaction with Hg (II) ions, at microconcentration of a pollutant (0.025-5.0 mkmol/dm3), has a zero order of reaction. Rate of a reaction does not depend on initial components concentration and is defined by process of Hg (II) ions diffusion to organic ligands. High correlation of a HA sorption capacity to Hg (II) ions is observed: with the nitrogen content and maintenance of amino groups (according to a 13C-NMR, element composition) and negative correlation - with degree of HA aromaticity. It testifies to primary binding of Hg (II) ions by amino-acid fragments of a HA molecule peripheral part. When concentration of Hg (II) ions increases, binding proceeds on carboxylic and phenolic groups of a molecule nuclear part. Higher order of kinetic models reaction and FTIR spectroscopy data testify to it. Comparison of FTIR spectra of HA preparations and mercury humates, shows that Hg (II) ions binding in humate complexes is carried out mainly by -COOH. Reduction of a spectral line intensity not ionized -COOH at 1700-1720 sm-1 and intensity increases of dissymetric valency vibration at 1610-1650 sm-1 diagnose increase

  2. Stereoselective analysis of D and L dansyl amino acids as the mixed chelate copper(II) complexes by HPLC.

    PubMed

    Lam, S

    1984-09-01

    This paper reviews the mixed chelation approach to resolution of the optical isomers of D and L dansyl amino acids by high performance liquid chromatography. The use of eluants containing Cu(II) complexes of L-proline, L-arginine, L-histidine, and L-histidine methyl ester effected the separation of many D and L amino acids, including those with aliphatic, polar, and aromatic substituents. The mechanism of separation, which is based on the preferential ternary complex formation of the analyte amino acid and the chiral chelate with Cu(II) in the mobile phase, is discussed. The stereoselectivity depends mainly on the different steric interactions between the alkyl side chains of the amino acid analytes and the chiral ligands coordinating around Cu(II), although such parameters as pH, temperature, organic modifier, and concentration of the chiral additive also affect the chromatographic separation. Among the chiral ligands studied, L-histidine methyl ester is unique in that it possesses both achiral selectivity for the dansyl amino acids and chiral selectivity for the respective D and L enantiomers. With a mobile phase gradient of acetonitrile in a buffer containing Cu(II) L-histidine methyl ester complex, a stereoselective procedure was devised for the analysis of D and L amino acid enantiomers, achieving the separation that the current amino acid analyzer could not perform. Finally, the use of the mixed chelation approach in two biomedical studies is described. In the first application, the histidine methyl ester gradient was adapted for analyzing amino acids in cerebrospinal fluid; in the second, an L-aspartame Cu(II) complex eluant was developed for measuring the urine concentration of D and L pipecolic acid (piperidine-2-carboxylic acid), a metabolite of lysine. PMID:6490790

  3. Novel one-dimensional lanthanide acrylic acid complexes: an alternative chain constructed by hydrogen bonding

    SciTech Connect

    Li Hui . E-mail: lihui@bit.edu.cn; Hu Changwen

    2004-12-01

    Novel one-dimensional (1D) chains of three lanthanide complexes La(L{sup 1}){sub 3}(CH{sub 3}OH)].CH{sub 3}OH (L{sup 1}=(E)-3-(2-hydroxyl-phenyl)-acrylic acid) 1, La(L{sup 2}){sub 3}(H{sub 2}O){sub 2}].2.75H{sub 2}O (L{sup 2}=(E)-3-(3-hydroxyl-phenyl)-acrylic acid) 2, and La(L{sup 3}){sub 3}(CH{sub 3}OH){sub 2}(H{sub 2}O)].CH{sub 3}OH (L{sup 3}=(E)-3-(4-hydroxyl-phenyl)-acrylic acid) 3 are reported. The crystal structure data are as follows for 1: C{sub 29}H{sub 29}LaO{sub 11}, monoclinic, P2{sub 1}/n, a=15.4289(12)A, b=7.9585(6)A, c=23.041(2)A, {beta}=99.657(2){sup o}, Z=4, R{sub 1}=0.0637, wR{sub 2}=0.0919; for 2: C{sub 27}H{sub 30.50}LaO{sub 13.75}, triclinic, P-1, a=8.4719(17)A, b=13.719(3)A, c=14.570(3)A, {alpha}=62.19(3){sup o}, {beta}=99.657(2){sup o}, {gamma}=78.22(3){sup o}, Z=2, R{sub 1}=0.0384, wR{sub 2}=0.0820; and for 3: C{sub 30}H{sub 35}LaO{sub 13}, monoclinic, P2(1)/c, a=9.5667(6)A, b=24.3911(15)A, c=14.0448(9)A, {beta}=109.245(2){sup o}, Z=4, R{sub 1}=0.0374, wR{sub 2}=0.0630. All the three structure data were collected using graphite monochromated molybdenum K{alpha} radiation and refined using full-matrix least-squares techniques on F{sup 2}. These structures show that four kinds of the carboxylato bridge modes are included in these chains to link the La(III) ions. It is the first time that it has been found that the intra-chain hydrogen bonding can construct an alternative chain even, when the coordination bridge mode is the same along the chain (complex 2). There are 2D and 3D hydrogen bonding in the crystal lattices of complexes 1-3.

  4. Characterization of the Mycobacterial Acyl-CoA Carboxylase Holo Complexes Reveals Their Functional Expansion into Amino Acid Catabolism

    PubMed Central

    Ehebauer, Matthias T.; Zimmermann, Michael; Jakobi, Arjen J.; Noens, Elke E.; Laubitz, Daniel; Cichocki, Bogdan; Marrakchi, Hedia; Lanéelle, Marie-Antoinette; Daffé, Mamadou; Sachse, Carsten; Dziembowski, Andrzej; Sauer, Uwe; Wilmanns, Matthias

    2015-01-01

    Biotin-mediated carboxylation of short-chain fatty acid coenzyme A esters is a key step in lipid biosynthesis that is carried out by multienzyme complexes to extend fatty acids by one methylene group. Pathogenic mycobacteria have an unusually high redundancy of carboxyltransferase genes and biotin carboxylase genes, creating multiple combinations of protein/protein complexes of unknown overall composition and functional readout. By combining pull-down assays with mass spectrometry, we identified nine binary protein/protein interactions and four validated holo acyl-coenzyme A carboxylase complexes. We investigated one of these - the AccD1-AccA1 complex from Mycobacterium tuberculosis with hitherto unknown physiological function. Using genetics, metabolomics and biochemistry we found that this complex is involved in branched amino-acid catabolism with methylcrotonyl coenzyme A as the substrate. We then determined its overall architecture by electron microscopy and found it to be a four-layered dodecameric arrangement that matches the overall dimensions of a distantly related methylcrotonyl coenzyme A holo complex. Our data argue in favor of distinct structural requirements for biotin-mediated γ-carboxylation of α−β unsaturated acid esters and will advance the categorization of acyl-coenzyme A carboxylase complexes. Knowledge about the underlying structural/functional relationships will be crucial to make the target category amenable for future biomedical applications. PMID:25695631

  5. Topical polyriboinosinic-polyribocytidylic acid complex in the treatment of recurrent genital herpes.

    PubMed Central

    Crane, L R; Levy, H B; Lerner, A M

    1982-01-01

    Polyriboinosinic-polyribocytidylic acid complexed with poly-l-lysine and carboxymethylcellulose [poly(ICLC)] is a potent interferon inducer when given parenterally to humans. Topical application in animal models has shown beneficial antiviral and clinical effects. In a randomized, double-blinded, placebo-controlled trial of topical poly(ICLC) in recurrent genital herpes simplex virus infection, five clinical and two virological parameters were followed. Fifty-seven men and women, with 78 recurrences of genital herpes, were stratified by sex. No clinical or antiviral differences between poly(ICLC) and placebo groups in either stratum were found. Further analysis of male subgroups by age and size of lesions showed no changes in the rapidity of healing or viral shedding. PMID:7049075

  6. Filler modification for papermaking with starch/oleic acid complexes with the aid of calcium ions.

    PubMed

    Huang, Xiujie; Shen, Jing; Qian, Xueren

    2013-10-15

    To mitigate the negative effect of filler addition on paper strength and improve filler retention, filler modification with hydrogen bonding polymers (e.g., starch) or their composites is an interesting research topic. Differing from previous reports, the concept related to the deposition of starch/oleic acid complexes on precipitated calcium carbonate (PCC) with the aid of calcium ions was demonstrated. The introduction of calcium ions resulted in effective starch deposition. As a result of filler modification, filler retention and the tensile strength of the filled paper were simultaneously improved essentially due to the aggregation of PCC particles in filler modification process as well as improved filler bondability. The concept demonstrated in this brief study may provide an alternative approach to filler bondability enhancement for improved papermaking performances. PMID:23987430

  7. Effect of iron poly (sorbitolgluconic acid) complex on urinary cellular excretion.

    PubMed

    Elliott, H L; Lawrence, J R; Campbell, B C; Goldberg, A; Smart, L E

    1981-01-01

    The intramuscular injection of 250 mg iron poly (sorbitol-gluconic acid) complex caused no increase in urinary cellular or bacterial excretion in 8 patients with chronic pyelonephritis, 4 patients with non-infective renal disease, and 4 controls. However, in 4 patients with chronic infective disease of the renal tract given 500 g there was a significant increase in cellular excretion. This response was not seen in 2 control patients, nor in 2 patients with non-infective renal disease. Using a differential staining technique, this increase in urinary cellular excretion was found to be due, not to leucocytes, but to renal tubular cells. The precise significance of this is unclear, but there would be concern that the high concentration of excreted iron was providing a 'toxic' insult to susceptible, infection-damaged cells. PMID:7226874

  8. A pharmacokinetic and clinical evaluation of iron poly (sorbitol-gluconic acid) complex.

    PubMed

    Campbell, B C; Lawrence, J R; Sumner, D J; Kelman, A; Smith, A; Elliott, H L; Goldberg, A

    1980-01-01

    The pharmacokinetics of iron poly (sorbitol-gluconic acid) complex (IPSG) were studied following a single intramuscular injection of 59Fe-labelled IPSG to 4 iron deficient-patients. The results showed a more rapid uptake of iron from the site of injection than that reported with iron dextran while there was a lower urinary excretion than found with iron sorbitol citrate. A clinical study was carried out in 11 patients with iron deficiency anaemia. Patients were allocated at random to receive IPSG as either 250 mg or 500 mg elemental iron per week for 8 weeks. A satisfactory response to therapy was obtained with each regimen whether measured by an increase in haemoglobin concentration or in serum ferritin concentration. Few side-effects were encountered but discomfort and staining at the injection site was found on the higher dose schedule. PMID:7208542

  9. Extraction of lycopene from tomato paste by ursodeoxycholic acid using the selective inclusion complex method.

    PubMed

    Seifi, Mahmoud; Seifi, Parisa; Hadizadeh, Farzin; Mohajeri, Seyed Ahmad

    2013-11-01

    Lycopene, a precursor of β-carotene with well-known antioxidant activity and powerful health properties, can be found in many natural products such as tomato (Lycopersicon esculentum), watermelon, red pepper, and papaya. Many separation methods have been reported for extracting lycopene from its sources. The inclusion complex is an effective method for extraction and purification of organic chemicals. This procedure has 2 main components: host and guest molecules. In this study, lycopene (guest) was extracted from tomato paste by ursodeoxycholic acid, the inclusive agent (host). The molecular structure of the extracted lycopene was then confirmed by (1) HNMR and its purity was evaluated using high-performance liquid chromatography and UV-Vis spectrophotometry methods, in comparison with a standard product. The results indicated that the proposed separation method was very promising and could be used for the extraction and purification of lycopene from tomato paste. PMID:24111697

  10. The guanidine and maleic acid (1:1) complex. The additional theoretical and experimental studies

    NASA Astrophysics Data System (ADS)

    Drozd, Marek; Dudzic, Damian

    2012-04-01

    On the basis of experimental literature data the theoretical studies for guanidinium and maleic acid complex with using DFT method are performed. In these studies the experimental X-ray data for two different forms of investigated crystal were used. During the geometry optimization process one equilibrium structure was found, only. According to this result the infrared spectrum for one theoretical molecule was calculated. On the basis of potential energy distribution (PED) analysis the clear-cut assignments of observed bands were performed. For the calculated molecule with energy minimum the highest occupied molecular orbital (HOMO) and the lowest unoccupied molecular orbital (LUMO) were obtained and graphically illustrated. The energy difference (GAP) between HOMO and LUMO was analyzed. Additionally, the nonlinear properties of this molecule were calculated. The α and β (first and second order) hyperpolarizability values are obtained. On the basis of these results the title crystal was classified as new second order NLO generator.

  11. Inelastic neutron scattering study of tetramethylpyrazine in the complex with chloranilic acid

    NASA Astrophysics Data System (ADS)

    Prager, M.; Pawlukojc, A.; Sobczyk, L.; Grech, E.; Grimm, H.

    2005-09-01

    The tunnel splitting of the methyl librational ground states in the hydrogen bonded tetramethylpyrazine-chloranilic acid (TMP-CLA) complex are determined for temperatures T<=28 K by high resolution neutron spectroscopy. Three tunnel modes are resolved at T = 2.4 K. Their relative intensities show that the crystal structure must be different from the proposed space group. Tunnelling and methyl librational modes from the measured density of states are combined into rotational potentials. There are discrepancies of activation energies calculated for these potentials and those obtained from quasielastic scattering of neutrons at T>=50 K due to structural differences in the two respective temperature regimes. Rotational potentials in TMP-CLA are significantly weaker as in pure TMP.

  12. Capillary HPLC/QTOF-MS for characterizing complex naphthenic acid mixtures and their microbial transformation.

    PubMed

    Bataineh, M; Scott, A C; Fedorak, P M; Martin, J W

    2006-12-15

    A rapidly expanding oil sands industry in Canada produces and indefinitely stores large volumes of toxic aqueous tailings containing high concentrations of naphthenic acids (NAs), a complex mixture of naturally occurring aliphatic or alicyclic carboxylic acids. Although there is an acknowledged need to reduce the environmental risks posed by NAs, little is understood about their environmental fate due to a lack of appropriate analytical methods. A dilute-and-shoot reversed-phase capillary HPLC/QTOF-MS method was developed that combines high specificity and sensitivity, quantitative capabilities, the ability to detect novel transformation products, and new structural information within each NA isomer class. HPLC separated NAs, based on carbon number, degree of cyclization, and the extent of alkyl branching, and in so doing increased analytical sensitivity up to 350-fold while providing additional specificity compared to infusion techniques. For tailings water, an interlaboratory study revealed many differences in isomer class profiles compared to an established GC/MS method, much of which was attributed to the misclassification of oxidized NAs (i.e., NA + O) by low-resolution GC/MS. HPLC/QTOF-MS enabled the detection of oxidized products in the same chromatographic run, and Van Krevelen diagrams were adapted to visualize the complex data. A marked decrease of retention times was evident in Syncrude tailings water compared to a commercial mixture, suggesting that tailings water is dominated by highly persistent alkyl-substituted isomers. A biodegradation study revealed that tailings water microorganisms preferentially deplete the least alkyl-substituted fraction and may be responsible for the NA profile in aged tailings water. PMID:17165827

  13. Synthesis of large surface area nano-sized BiVO{sub 4} by an EDTA-modified hydrothermal process and its enhanced visible photocatalytic activity

    SciTech Connect

    Sun Wanting; Xie Mingzheng; Jing Liqiang; Luan Yunbo; Fu Honggang

    2011-11-15

    In this work, monoclinic scheelite-type BiVO{sub 4} nanoparticle with large surface area has been successfully synthesized, using Bi(NO{sub 3}){sub 3} and NH{sub 4}VO{sub 3} as raw materials, through a hydrothermal process in the presence of ethylene diamine tetraacetic acid (EDTA). It is demonstrated that the nanoparticle size of as-prepared BiVO{sub 4} becomes small by decreasing hydrothermal temperature, shortening hydrothermal reaction time and increasing EDTA amount used. The resulting BiVO{sub 4} nanoparticle with large surface area exhibits a good photocatalytic performance for degrading phenol solution as a model organic pollutant under visible illumination. The key of this method is the chelating role of EDTA group in the synthetic process that it can greatly control the concentration of Bi{sup 3+}, leading to the growth inhibition of BiVO{sub 4} crystallite. The work provides a route for the synthesis of Bi-containing nano-sized composite oxides with large surface area. - Graphical abstract: High visible active nano-sized BiVO{sub 4} photocatalyst with large surface area is successfully synthesized, which is attributed to the chelating role of EDTA group inhibiting the growth of BiVO{sub 4} crystallites. Highlights: > Monoclinic scheelite-type BiVO{sub 4} nanoparticle with large surface area has been synthesized by a hydrothermal process. > Key of this method is the chelating role of EDTA group inhibiting the growth of BiVO{sub 4} crystallites. > Resulting nano-sized BiVO{sub 4} exhibits a good photocatalytic activity for degrading phenol under visible illumination.

  14. Whole cowpea meal fortified with NaFeEDTA reduces iron deficiency among Ghanaian school children in a malaria endemic area.

    PubMed

    Abizari, Abdul-Razak; Moretti, Diego; Zimmermann, Michael B; Armar-Klemesu, Margaret; Brouwer, Inge D

    2012-10-01

    Cowpeas, like other legumes, contain high amounts of native iron but are rich in phytic acid (PA) and polyphenols (PP) that inhibit iron absorption. NaFeEDTA may overcome the combined inhibitory effect of PA and PP. Our objective was to test the efficacy of NaFeEDTA-fortified cowpea meal in improving iron status of school children in a malaria endemic area. We conducted a double-blind, controlled trial with 5- to 12-y-old school children from 2 rural communities in northern Ghana (n = 241). Eligible children were randomly assigned to 2 treatment groups to receive either cowpea meal fortified with 10 mg Fe/meal as NaFeEDTA, or an identical but nonfortified cowpea meal. Meals were provided 3 d/wk for a period of ~7 mo under strict supervision. Mass deworming and malaria antigenemia screening and treatment were carried out at baseline and 3.5 mo into the trial. Consumption of cowpea flour fortified with NaFeEDTA resulted in improvement of hemoglobin (P < 0.05), serum ferritin (P < 0.001), and body iron stores (P < 0.001) and reduction of transferrin receptor (P < 0.001) compared with nonfortified flour. Fortification resulted in a 30 and 47% reduction in the prevalence of iron deficiency (ID) and iron deficiency anemia (IDA) (P < 0.05), respectively. The results indicate that fortification of cowpea flour with NaFeEDTA overcomes the combined inhibitory effect of PA and PP and, when used for targeted school-based fortification of cowpea flour, is effective in reducing the prevalence of ID and IDA among school children in malaria endemic rural northern Ghana. PMID:22915294

  15. Neodymium(III) Complexes of Dialkylphosphoric and Dialkylphosphonic Acids Relevant to Liquid-Liquid Extraction Systems.

    PubMed

    Lumetta, Gregg J; Sinkov, Sergey I; Krause, Jeanette A; Sweet, Lucas E

    2016-02-15

    The complexes formed during the extraction of neodymium(III) into hydrophobic solvents containing acidic organophosphorus extractants were probed by single-crystal X-ray diffractometry, visible spectrophotometry, and Fourier-transform infrared spectroscopy. The crystal structure of the compound Nd(DMP)3 (1, DMP = dimethyl phosphate) revealed a polymeric arrangement in which each Nd(III) center is surrounded by six DMP oxygen atoms in a pseudo-octahedral environment. Adjacent Nd(III) ions are bridged by (MeO)2POO(-) anions, forming the polymeric network. The diffuse reflectance visible spectrum of 1 is nearly identical to that of the solid that is formed when an n-dodecane solution of di(2-ethylhexyl)phosphoric acid (HA) is saturated with Nd(III), indicating a similar coordination environment around the Nd center in the NdA3 solid. The visible spectrum of the HA solution fully loaded with Nd(III) is very similar to that of the NdA3 material, both displaying hypersensitive bands characteristic of an pseudo-octahedral coordination environment around Nd. These spectral characteristics persisted across a wide range of organic Nd concentrations, suggesting that the pseudo-octahedral coordination environment is maintained from dilute to saturated conditions. PMID:26815878

  16. Fatty acid nitroalkenes induce resistance to ischemic cardiac injury by modulating mitochondrial respiration at complex II

    PubMed Central

    Koenitzer, Jeffrey R.; Bonacci, Gustavo; Woodcock, Steven R.; Chen, Chen-Shan; Cantu-Medellin, Nadiezhda; Kelley, Eric E.; Schopfer, Francisco J.

    2015-01-01

    Nitro-fatty acids (NO2-FA) are metabolic and inflammatory-derived electrophiles that mediate pleiotropic signaling actions. It was hypothesized that NO2-FA would impact mitochondrial redox reactions to induce tissue-protective metabolic shifts in cells. Nitro-oleic acid (OA-NO2) reversibly inhibited complex II-linked respiration in isolated rat heart mitochondria in a pH-dependent manner and suppressed superoxide formation. Nitroalkylation of Fp subunit was determined by BME capture and the site of modification by OA-NO2 defined by mass spectrometric analysis. These effects translated into reduced basal and maximal respiration and favored glycolytic metabolism in H9C2 cardiomyoblasts as assessed by extracellular H+ and O2 flux analysis. The perfusion of NO2-FA induced acute cardioprotection in an isolated perfused heart ischemia/reperfusion (IR) model as evidenced by significantly higher rate-pressure products. Together these findings indicate that NO2-FA can promote cardioprotection by inducing a shift from respiration to glycolysis and suppressing reactive species formation in the post-ischemic interval. PMID:26722838

  17. Fatty acid nitroalkenes induce resistance to ischemic cardiac injury by modulating mitochondrial respiration at complex II.

    PubMed

    Koenitzer, Jeffrey R; Bonacci, Gustavo; Woodcock, Steven R; Chen, Chen-Shan; Cantu-Medellin, Nadiezhda; Kelley, Eric E; Schopfer, Francisco J

    2016-08-01

    Nitro-fatty acids (NO2-FA) are metabolic and inflammatory-derived electrophiles that mediate pleiotropic signaling actions. It was hypothesized that NO2-FA would impact mitochondrial redox reactions to induce tissue-protective metabolic shifts in cells. Nitro-oleic acid (OA-NO2) reversibly inhibited complex II-linked respiration in isolated rat heart mitochondria in a pH-dependent manner and suppressed superoxide formation. Nitroalkylation of Fp subunit was determined by BME capture and the site of modification by OA-NO2 defined by mass spectrometric analysis. These effects translated into reduced basal and maximal respiration and favored glycolytic metabolism in H9C2 cardiomyoblasts as assessed by extracellular H(+) and O2 flux analysis. The perfusion of NO2-FA induced acute cardioprotection in an isolated perfused heart ischemia/reperfusion (IR) model as evidenced by significantly higher rate-pressure products. Together these findings indicate that NO2-FA can promote cardioprotection by inducing a shift from respiration to glycolysis and suppressing reactive species formation in the post-ischemic interval. PMID:26722838

  18. nC60 deposition kinetics: the complex contribution of humic acid, ion concentration, and valence.

    PubMed

    McNew, Coy P; LeBoeuf, Eugene J

    2016-07-01

    The demonstrated toxicity coupled with inevitable environmental release of nC60 raise serious concerns about its environmental fate and transport, therefore it is crucial to understand how nC60 will interact with subsurface materials including attached phase soil and sediment organic matter (AP-SOM). This study investigated the attachment of nC60 onto a Harpeth humic acid (HHA) coated silica surface under various solution conditions using a quartz crystal microbalance with dissipation monitoring. The HHA coating greatly enhanced nC60 attachment at low ion concentrations while hindering attachment at high ion concentrations in the presence of both mono and divalent cations. At low ion concentrations, the HHA greatly reduced the surface potential of the silica, enhancing nC60 deposition through reduction in the electrostatic repulsion. At high ion concentrations however, the reduced surface potential became less important due to the near zero energy barrier to deposition and therefore non-DLVO forces dominated, induced by compaction of the HHA layer, and leading to hindered attachment. In this manner, observed contributions from the HHA layer were more complex than previously reported and by monitoring surface charge and calculated DLVO interaction energy alongside attachment experiments, this study advances the mechanistic understanding of the variable attachment contributions from the humic acid layer. PMID:27061365

  19. Arginase-boronic acid complex highlights a physiological role in erectile function.

    PubMed

    Cox, J D; Kim, N N; Traish, A M; Christianson, D W

    1999-11-01

    The crystal structure of the complex between the binuclear manganese metalloenzyme arginase and the boronic acid analog of L-arginine, 2(S)-amino-6-boronohexanoic acid (ABH), has been determined at 1.7 A resolution from a crystal perfectly twinned by hemihedry. ABH binds as the tetrahedral boronate anion, with one hydroxyl oxygen symmetrically bridging the binuclear manganese cluster and a second hydroxyl oxygen coordinating to Mn2+A. This binding mode mimics the transition state of a metal-activated hydroxide mechanism. This transition state structure differs from that occurring in NO biosynthesis, thereby explaining why ABH does not inhibit NO synthase. We also show that arginase activity is present in the penis. Accordingly, the tight binding and specificity of ABH allows us to probe the physiological role of arginase in modulating the NO-dependent smooth muscle relaxation required for erection. Strikingly, ABH causes significant enhancement of nonadrenergic, noncholinergic nerve-mediated relaxation of penile corpus cavernosum smooth muscle, suggesting that arginase inhibition sustains L-arginine concentrations for NO synthase activity. Therefore, human penile arginase is a potential target for therapeutic intervention in the treatment of erectile dysfunction. PMID:10542097

  20. Synergy studies of the fungicidal plant saponin, CAY-1, with EDTA and silver

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Background: CAY-1 is a fungicidal saponin produced by Capsicum species. Silver (Ag) and EDTA inhibit Aspergillus and Fusarium growth. This study determined Ag and EDTA fungicidal properties for several Aspergillus and Fusarium species both alone and with CAY-1. Methods: CAY-1 was purified by col...