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Sample records for chelated uranyl antibody

  1. Development of a Recombinant Antibody with Specificity for Chelated Uranyl Ions

    Energy Technology Data Exchange (ETDEWEB)

    X. Li; A.M. Kriegel; T.C. Bishop; R.C. Blake; E. Figueiredo; H. Yu; D.A. Blake

    2005-04-18

    The goal of our project is to continue the development of new techniques for rapid, automated identification of radionuclides, metals, and chelators that may contaminant sur face and groundwater at DOE sites. One of the four specific aims of the present project is to develop new technologies in antibody engineering that will enhance our immunosensor program. Recombinant antibodies have potential advantages over monoclonal antibodies produced by standard hybridoma technology. The cloned genes represent a stable, recoverable source for antibody production. In addition, the recombinant format offers opportunities for protein engineering that enhances antibody performance and for studies that relate antibody sequence to binding activity. In this study, a hybridoma that synthesized an antibody (12F6) that recognized a 1:1 complex between 2,9-dicarboxyl-1,10- phenanthroline (DCP) and UO{sub 2}{sup 2+} was used as a source of RNA for the development of a recombinant (Fab){sub 2} fragment. RNA was isolated from the 12F6 hybridoma and the cDNA encoding the entire {kappa} light chain and the linked VH and C1 portions of the heavy chain were amplified from total RNA. cDNA sequences were verified by comparison with the N-terminal amino acid sequences of the light and heavy chains of the native 12F6 monoclonal antibody. A leader sequence and appropriate restriction sites were added to each chain, and the fragments were ligated into a commercial dicistronic vector (pBudCE4.1, Invitrogen, Inc.). COS-1 cells were transfected with this vector and the culture supernatant was assayed for activity and the (Fab){sub 2} protein. Cells transfected with vector containing 12F6 cDNA synthesized and secreted recombinant (Fab){sub 2} fragments that bound to the UO{sub 2}{sup 2+}-DCP complex with an affinity indistinguishable from that of a (Fab){sub 2} fragment prepared from the native antibody. Molecular models of the heavy and light chain variable domains were constructed according to the

  2. Nonionic metal-chelating surfactants mediated solvent-free thermo-induced separation of uranyl

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    Larpent, Ch.; Prevost, S. [Versailles-St-Quentin Univ., Institut Lavoisier, UMR-CNRS 8180, 78 - Versailles (France); Prevost, S.; Zemb, Th.; Testard, F. [CEA Saclay, Dept. de Recherche sur l' Etat Condense, les Atomes et les Molecules (DSM/DRECAM/SCM/LIONS), 91 - Gif sur Yvette (France); Berthon, L. [CEA Valrho, Site de Marcoule, Dept. Radiochimie et Procedes (DEN/DRCP/SCPS/LCSE), 30 (France)

    2007-08-15

    Thermo-responsive metal-chelating surfactants permit the solvent-free, cloud point extraction of uranyl nitrate and afford a real molecular economy compared to conventional separation techniques. (authors)

  3. Deciphering the energy landscape of the interaction uranyl-DCP with antibodies using dynamic force spectroscopy.

    Science.gov (United States)

    Teulon, Jean-Marie; Parot, Pierre; Odorico, Michael; Pellequer, Jean-Luc

    2008-11-15

    Previous studies on molecular recognition of uranyl-DCP (dicarboxy-phenanthroline chelator) compound by two distinct monoclonal antibodies (Mabs U04S and U08S) clearly showed the presence of a biphasic shape in Bell-Evans' plots and an accentuated difference in slopes at the high loading rates. To further explore the basis in the slope difference, we have performed complementary experiments using antibody PHE03S, raised against uranyl-DCP but, presenting a strong cross-reactivity toward the DCP chelator. This work allowed us to obtain a reallocation of the respective contributions of the metal ion itself and that of the chelator. Results led us to propose a 2D schematic model representing two energy barriers observed in the systems Mabs U04S- and U08S-[UO(2)-DCP] where the outer barrier characterizes the interaction between UO(2) and Mab whereas the inner barrier characterizes the interaction between DCP and Mab. Using dynamic force spectroscopy, it is thus possible to dissect molecular interactions during the unbinding between proteins and ligands.

  4. New thermo-sensitive chelating surfactants for selective solvent-free extraction of uranyl nitrate

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    Prevost, S.; Larpent, C.; Testard, F.; Coulombeau, H.; Baczko, K.; Berthon, L.; Desvaux, H.; Madic, C.; Zemb, T

    2004-07-01

    Functional surfactants were synthesised by grafting a chelating group (amino-acid residue) to the tip of a poly-ethoxylated nonionic surfactant chain (C{sub i}E{sub j}: C{sub i}H{sub 2i}+1(OCH{sub 2}CH{sub 2}){sub j}OH)) or in a branched position. C{sub i}E{sub j} nonionic surfactants are known to be thermo-reversible and to exhibit a clouding phenomenon associated to phase separation of micelles. The functional surfactants retain both surface-active properties, characteristic thermo-reversible behaviour and have efficient complexing properties toward uranyl. In the presence of uranyl nitrate, small micelles are formed at ambient temperature and the de-mixing leads to a separation of the target ion trapped by the functional surfactant (cloud point extraction). Those surfactants are more efficient than mixture of classical C{sub i}E{sub j} and complexing agent solubilized in the micelles. This reveals a synergistic effect of the covalent bond between the chelating group and the nonionic surfactant C{sub i}E{sub j}. This paper presents a systematic study of the extraction and aggregation properties and the influence of the nature of the ions. (authors)

  5. Thermo-responsive metal-chelating surfactants. Properties and use in cloud point extraction of uranyl nitrate

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    Prevost, S.; Coulombeau, H. [CEA, IRAMIS, SCM, LIONS, 91 - Gif-sur-Yvette (France); Univ. de Versailles St Quentin en Y. Institut Lavoisier UMR CNRS 8180 (France); Baczko, K.; Larpent, C. [Univ. de Versailles St Quentin en Y. Institut Lavoisier UMR CNRS 8180 (France); Berthon, L.; Zorz, N. [CEA/DEN/DRCP/SCPS/LCSE, 30 - Bagnols sur Ceze (France); Desvaux, H.; Testard, F. [CEA, IRAMIS, SCM, LIONS, 91 - Gif-sur-Yvette (France); Zemb, T. [ICSM, UMR 5257 CEA/CNRS/UM2/ENSCM, 30 - Bagnols sur Ceze (France)

    2009-03-15

    The properties of new thermo-responsive functional surfactants, capable of forming a metal chelate, synthesized by grafting a diamide group (amino-acid residue) to the tip hydrophilic endgroup or in a branched position to polyoxyethylene nonionic surfactants [C{sub i}E{sub j}:C{sub i}H{sub 2i+1}(OCH{sub 2}CH{sub 2}){sub j}OH)], are studied. Their use in cloud point extraction of uranyl nitrate is tested. The reversible temperature-dependent behavior of classical non-ionic surfactants associated to phase separation of micellar solutions known as clouding behavior is exploited for separation based on cation specific binding to the chelating group. The functional surfactants under investigation combine surface-active properties and characteristic thermoreversible behavior with a capacity to bind uranyl cation. The influence of the complexation on the cloud points of functional surfactants is determined. The chelating surfactants are found efficient for the cloud point extraction of uranyl nitrate at low surfactant-to-uranyl ratio. These new thermoresponsive surfactants with chelating properties hold most promise for the development of new solvent free extraction processes.

  6. Thermo-responsive Metal-chelating Surfactants: Properties and Use in Cloud Point Extraction of Uranyl Nitrate

    Energy Technology Data Exchange (ETDEWEB)

    Prevost, S.; Coulombeau, H.; Baczko, K.; Larpent, C. [Univ Versailles St Wuentin Y, Inst Lavoisier, UMR 8180, CNRS, F-78035 Versailles, (France); Prevost, S.; Coulombeau, H.; Desvaux, H.; Testard, F. [CEA, IRAMIS, SCM, LIONS, F-91191 Gif Sur Yvette, (France); Berthon, L.; Zorz, N. [CEA, DEN DRCP SCPS LCSE, F-30207 Bagnols Sur Ceze, (France); Zemb, Th. [ICSM, UMR 5257, CEA CNRS UM2 ENSCM, F-30207 Bagnols Sur Ceze, (France)

    2009-07-01

    The properties of new thermo-responsive functional surfactants, capable of forming a metal chelate, synthesized by grafting a diamide group (amino-acid residue) to the tip hydrophilic end-group or in a branched position to polyoxyethylene nonionic surfactants [CiEj: C{sub i}H{sub 2i+1}(OCH{sub 2}CH{sub 2}){sub j}OH)], are studied. Their use in cloud point extraction of uranyl nitrate is tested. The reversible temperature-dependent behavior of classical non-ionic surfactants associated to phase separation of micellar solutions known as clouding behavior is exploited for separation based on cation specific binding to the chelating group. The functional surfactants under investigation combine surface-active properties and characteristic thermo-reversible behavior with a capacity to bind uranyl cation. The influence of the complexation on the cloud points of functional surfactants is determined. The chelating surfactants are found efficient for the cloud point extraction of uranyl nitrate at low surfactant-to-uranyl ratio. These new thermo-responsive surfactants with chelating properties hold most promise for the development of new solvent free extraction processes. (authors)

  7. Tumor targeting of radiolabeled antibodies using HYNIC chelate

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    Lee, Tae Sup; Chung, Wee Sup; Woo, Kwang Sun; Choi, Tae Hyun; Chung, Hye Kyung; Lee, Myung Jin; Kim, So Yeon; Jung, Jae Ho; Choi, Chang Woon; Lim, Sang Moo [KIRAMS, Seoul (Korea, Republic of); Darwati, Siti [National Nuclear Energy Agency, Tangerang (Indonesia)

    2004-07-01

    There is an increasing interest in the use of labeled antibodies for diagnosis of cancers as well as for therapy. Various radiolabeling methods have been used in order to obtain better tumor specific targeting for detection and therapy. It was generally used to tumor targeted immunotherapy and immunodetection that lym-1, mouse monoclonal antibody, was specific binding to surface antigen of Raji. The 3E8 antibody was produced from humanized anti-TAG-72 monoclonal antibody (AKA) by amino acid change in 95-99 residues of heavy chain complementary determinant regions (HCDRs) 3 using phage displayed library technology. In this study, we are investigating the usefulness of HYNIC chelate as a bifunctional chelating agent in radioimmunodetecton of tumor. Two types of antibodies, Lym-1 and 3E8, were used for the conjugation with HYNIC chelate. Lym-1 and 3E8 are specific antibodies to surface antigen of Non-Hogkin's lymphoma and TAG-72 antigen of colorectal carcinoma, respectively. We prepare HYNIC-antibody conjugates, determine radiolabeling yield with {sup 99m}Tc and evaluate tumor targeting in tumor bearing nude mice model.

  8. Comparison of bifunctional chelates for {sup 64}Cu antibody imaging

    Energy Technology Data Exchange (ETDEWEB)

    Ferreira, Cara L.; Crisp, Sarah; Bensimon, Corinne [MDS Nordion, Vancouver, BC (Canada); Yapp, Donald T.T.; Ng, Sylvia S.W. [British Columbia Cancer Agency Research Centre, Vancouver, BC (Canada); University of British Columba, The Faculty of Pharmaceutical Sciences, Vancouver, BC (Canada); Sutherland, Brent W. [British Columbia Cancer Agency Research Centre, Vancouver, BC (Canada); Gleave, Martin [Prostate Centre at Vancouver General Hospital, Vancouver, BC (Canada); Jurek, Paul; Kiefer, Garry E. [Macrocyclics Inc., Dallas, TX (United States)

    2010-11-15

    Improved bifunctional chelates (BFCs) are needed to facilitate efficient {sup 64}Cu radiolabeling of monoclonal antibodies (mAbs) under mild conditions and to yield stable, target-specific agents. The utility of two novel BFCs, 1-Oxa-4,7,10-triazacyclododecane-5-S-(4-isothiocyanatobenzyl)-4,7,10-triacetic acid (p-SCN-Bn-Oxo-DO3A) and 3,6,9,15-tetraazabicyclo[9.3.1]pentadeca-1(15),11,13-triene-4-S-(4-isothiocyanatobenzyl)-3,6,9-triacetic acid (p-SCN-Bn-PCTA), for mAb imaging with {sup 64}Cu were compared to the commonly used S-2-(4-isothiocyanatobenzyl)-1,4,7,10-tetraazacyclododecane-tetraacetic acid (p-SCN-Bn-DOTA). The BFCs were conjugated to trastuzumab, which targets the HER2/neu receptor. {sup 64}Cu radiolabeling of the conjugates was optimized. Receptor binding was analyzed using flow cytometry and radioassays. Finally, PET imaging and biodistribution studies were done in mice bearing either HER2/neu-positive or HER2/neu-negative tumors. {sup 64}Cu-Oxo-DO3A- and PCTA-trastuzumab were prepared at room temperature in >95% radiochemical yield (RCY) in <30 min, compared to only 88% RCY after 2 h for the preparation of {sup 64}Cu-DOTA-trastuzumab under the same conditions. Cell studies confirmed that the immunoreactivity of the mAb was retained for each of the bioconjugates. In vivo studies showed that {sup 64}Cu-Oxo-DO3A- and PCTA-trastuzumab had higher uptake than the {sup 64}Cu-DOTA-trastuzumab at 24 h in HER2/neu-positive tumors, resulting in higher tumor to background ratios and better tumor images. By 40 h all three of the {sup 64}Cu-BFC-trastuzumab conjugates allowed for clear visualization of the HER2/neu-positive tumors but not the negative control tumor. The antibody conjugates of PCTA and Oxo-DO3A were shown to have superior {sup 64}Cu radiolabeling efficiency and stability compared to the analogous DOTA conjugate. In addition, {sup 64}Cu-PCTA and Oxo-DO3A antibody conjugates may facilitate earlier imaging with greater target to background ratios than

  9. Uranyl binary and ternary chelates of tenoxicam. Synthesis, spectroscopic and thermal characterization of ternary chelates of tenoxicam and alanine with transition metals

    Science.gov (United States)

    El-Gamel, Nadia E. A.

    2007-11-01

    Ternary Fe(III), Co(II), Ni(II), Cu(II), Zn(II) and UO 2(II) chelates with tenoxicam (Ten) drug (H 2L 1) and dl-alanine (Ala) (HL 2) and also the binary UO 2(II) chelate with Ten were studied. The structures of the chelates were elucidated using elemental, molar conductance, magnetic moment, IR, diffused reflectance and thermal analyses. UO 2(II) binary chelate was isolated in 1:2 ratio with the formula [UO 2(H 2L) 2](NO 3) 2. The ternary chelates were isolated in 1:1:1 (M:H 2L 1:L 2) ratios and have the general formulae [M(H 2L 1)(L 2)(Cl) n(H 2O) m]· yH 2O (M = Fe(III) ( n = 2, m = 0, y = 2), Co(II) ( n = 1, m = 1, y = 2) and Ni(II) ( n = 1, m = 1, y = 3)); [M(H 2L 1)(L 2)](X) z· yH 2O (M = Cu(II) (X = AcO, z = 1, y = 0), Zn(II) (X = AcO, z = 1, y = 3) and UO 2(II) (X = NO 3, z = 1, y = 2)). IR spectra reveal that Ten behaves as a neutral bidentate ligand coordinated to the metal ions via the pyridine-N and carbonyl-O groups, while Ala behaves as a uninegatively bidentate ligand coordinated to the metal ions via the deprotonated carboxylate-O and amino-N. The magnetic and reflectance spectral data confirm that all the chelates have octahedral geometry except Cu(II) and Zn(II) chelates have tetrahedral structures. Thermal decomposition of the chelates was discussed in relation to structure and different thermodynamic parameters of the decomposition stages were evaluated.

  10. Characterization of Tumor-Avid Antibody Fragments Genetically Engineered for Mono-Specific Radionuclide Chelation

    Energy Technology Data Exchange (ETDEWEB)

    Quinn, T.P.

    2003-12-31

    The successful clinical application of targeted-radiopharmaceuticals depends on the development of molecules that optimize tumor specific radionuclide deposition and minimize non-specific organ irradiation. To this end, this proposal outlines a research effort to identify and evaluate novel antibodies and antibody fragments that bind breast tumors. The tumor-avid antibodies will be investigated for as imaging and therapeutic agents and to gain a better understanding of the pharmacokinetics and metabolism of radiolabeled tumor-avid antibody fragments through the use of site-specifically labeled molecules. Antibodies or antibody fragments, that bind breast carcinoma carbohydrate antigens, will be obtained from hybridoma or bacteriophage library screening. More specifically, antibody fragments that bind the carcinoma-associated Thomsen-Friedenreich (T) antigen will be radiolabeled with {sup 99m}Tc and {sup 188}Re at a natural amino acid chelation site and will be investigated in vivo for their abilities to target human breast tumors. In addition, site-specific radiolabeled antibody fragments will be biosynthesized using misacylated suppressor tRNAs. Homogeneously radiolabeled populations of antibody fragments will be used to investigate the effects of radionuclide location and chelation chemistries on their biodistribution and metabolism. It is hypothesized that site-specifically radiolabeled antibody fragments will possess enhanced tumor imaging and therapeutic properties due to optimal label location and conjugation chemistries. New insights into the factors that govern antibody metabolism in vivo are also expected from this work. Results from these studies should enhance our ability to design and synthesize radiolabeled antibody fragments that have improved pharmacokinetic properties. The studies in this proposal involve basic research into the development of antibody-based radiopharmaceuticals, with the ultimate goal of application in humans. This type of basic

  11. Engineering an antibody with picomolar affinity to DOTA chelates of multiple radionuclides for pretargeted radioimmunotherapy and imaging

    Energy Technology Data Exchange (ETDEWEB)

    Orcutt, Kelly Davis; Slusarczyk, Adrian L. [Department of Chemical Engineering, Massachusetts Institute of Technology, Cambridge, MA 02139 (United States); Cieslewicz, Maryelise [Department of Biological Engineering, Massachusetts Institute of Technology, Cambridge, MA 02139 (United States); Ruiz-Yi, Benjamin [Department of Chemical Engineering, Massachusetts Institute of Technology, Cambridge, MA 02139 (United States); Bhushan, Kumar R. [Division of Hematology/Oncology, Beth Israel Deaconess Medical Center, Boston, MA 02215 (United States); Frangioni, John V. [Division of Hematology/Oncology, Beth Israel Deaconess Medical Center, Boston, MA 02215 (United States); Department of Radiology, Beth Israel Deaconess Medical Center, Boston, MA 02215 (United States); Wittrup, K. Dane, E-mail: wittrup@mit.ed [Department of Chemical Engineering, Massachusetts Institute of Technology, Cambridge, MA 02139 (United States); Department of Biological Engineering, Massachusetts Institute of Technology, Cambridge, MA 02139 (United States); Koch Institute for Integrative Cancer Research, Massachusetts Institute of Technology, Cambridge, MA 02139 (United States)

    2011-02-15

    Introduction: In pretargeted radioimmunotherapy (PRIT), a bifunctional antibody is administered and allowed to pre-localize to tumor cells. Subsequently, a chelated radionuclide is administered and captured by cell-bound antibody while unbound hapten clears rapidly from the body. We aim to engineer high-affinity binders to 1,4,7,10-tetraazacyclododecane-1,4,7,10-tetraacetic acid (DOTA) chelates for use in PRIT applications. Methods: We mathematically modeled antibody and hapten pharmacokinetics to analyze hapten tumor retention as a function of hapten binding affinity. Motivated by model predictions, we used directed evolution and yeast surface display to affinity mature the 2D12.5 antibody to DOTA, reformatted as a single chain variable fragment (scFv). Results: Modeling predicts that for high antigen density and saturating bsAb dose, a hapten-binding affinity of 100 pM is needed for near-maximal hapten retention. We affinity matured 2D12.5 with an initial binding constant of about 10 nM to DOTA-yttrium chelates. Affinity maturation resulted in a 1000-fold affinity improvement to biotinylated DOTA-yttrium, yielding an 8.2{+-}1.9 picomolar binder. The high-affinity scFv binds DOTA complexes of lutetium and gadolinium with similar picomolar affinity and indium chelates with low nanomolar affinity. When engineered into a bispecific antibody construct targeting carcinoembryonic antigen, pretargeted high-affinity scFv results in significantly higher tumor retention of a {sup 111}In-DOTA hapten compared to pretargeted wild-type scFv in a xenograft mouse model. Conclusions: We have engineered a versatile, high-affinity, DOTA-chelate-binding scFv. We anticipate it will prove useful in developing pretargeted imaging and therapy protocols to exploit the potential of a variety of radiometals.

  12. Labeling of antibodies with a /sup 67/Ga-phenolic aminocarboxylic acid chelate. Pt. 1. Chemistry and labeling technique

    Energy Technology Data Exchange (ETDEWEB)

    Schuhmacher, J.; Matys, R.; Hauser, H.; Maier-Borst, W.; Matzku, S.

    1986-11-01

    As a chelating agent for labeling antibodies (Abs) with metallic radionuclides, a propionic acid substituted ethylenediamine N, N'-di-((o-hydroxyphenyl) acetic acid) (P-EDDHA), which tighly complexes /sup 67/Ga, was synthetized. The /sup 67/Ga-P-EDDHA chelate was coupled in aqueous solution to IgG at a molar ratio of 1:1 via carbodiimide. The average coupling yield was 15%. A specific activity of 4 mCi/mg IgG could be obtained with commercially supplied /sup 67/Ga. In vitro stability was evaluated in human serum at 37/sup 0/C and showed a half-life of about 120 h for the release of /sup 67/Ga from the labeled Ab during the initial phase of incubation. This in vitro halflife is similar to that measured for /sup 111/In-DTPA labeled Abs. Because of the high stability of the /sup 67/Ga-P-EDDHA chelate, the in vivo formation of radioactive lebeled transferrin by transchelation, as described for /sup 111/In-DTPA labeled Abs, should, however, be reduced by this labeling technique.

  13. A new bifunctional chelate, BrMe sub 2 HBED: An effective conjugate for radiometals and antibodies

    Energy Technology Data Exchange (ETDEWEB)

    Mathias, C.J.; Connett, J.M.; Philpott, G.W.; Welch, M.J. (Washington Univ. School of Medicine, St. Louis, MO (USA)); Sun, Yizhen; Martell, A.E. (Texas A and M Univ., College Station (USA))

    1990-04-18

    A new bifunctional chelate, N-(2-hydroxy-3,5-dimethylbenzyl)-N{prime}-(2-hydroxy-5-(bromoacetamido)benzyl)ethylenediamine-N,-N{prime}-diacetic acid (BrMe{sub 2}HBED), was designed and synthesized to bind trivalent cationic metals with monoclonal antibodies. The stability constants (log values) for indium complexed with a similar ligand, HBED, were increased over those of more commonly used ligands DTPA and EDTA. Predictably, the increased metal-ligand complex stability would expedite the in vivo clearance from nontarget regions and perhaps enhance the localization of the radiolabeled antibody (Ab). BrMe{sub 2}HBED was conjugated with the Ab (24 h) and then radiolabeled with indium-111 citrate (24 h). Additionally, the Ab was radiolabeled by using conventional methods ({sup 111}In-DTPA and {sup 125}I-lactoperoxidase) and then compared by measuring the in vitro stability, in vitro immunoreactivity(IR), and in vivo distribution and clearance. A 10:1 BrMe{sub 2} HBED:Ab mole ratio resulted in good labeling efficiency with {sup 111}In and more importantly a very high IR. In a hamster tumor model, {sup 111}In-BrMe{sub 2} HBED-labeled monoclonal antibody (1A3) had high uptake in the tumor tissue and preferable blood clearance compared to either of the more conventional radiolabeled 1A3 monoclonal antibodies ({sup 111}In-DTPA or {sup 125}I-lactoperoxidase). 49 refs., 4 figs., 8 tabs.

  14. Synthesis of phosphorylated calix[4]arene derivatives for the design of solid phases immobilizing uranyl cations

    Energy Technology Data Exchange (ETDEWEB)

    Maroun, E.B.; Hagege, A.; Asfari, Z. [Laboratoire de Chimie Analytique et Minerale, UMR 7178 ULP/CNRS/IN2P3 LC4, ECPM, Strasbourg Cedex (France); Basset, CH.; Quemeneur, E.; Vidaud, C. [CEA IBEB, SBTN, Centre de Marcoule, Bagnols-sur-Ceze (France)

    2009-07-01

    With the aim of developing supports for uranyl cations immobilisation, new 1, 3-alternate calix[4]arenes bearing both phosphonic acid functions as chelating sites and N-succinimide-4-oxa-butyrate as the anchoring arm were synthesised in good yields. The coupling of such calixarenes to a gel was performed and a successful immobilisation of uranyl cations was obtained. (authors)

  15. Uranyl ion coordination

    Science.gov (United States)

    Evans, H.T.

    1963-01-01

    A review of the known crystal structures containing the uranyl ion shows that plane-pentagon coordination is equally as prevalent as plane-square or plane-hexagon. It is suggested that puckered-hexagon configurations of OH - or H2O about the uranyl group will tend to revert to plane-pentagon coordination. The concept of pentagonal coordination is invoked for possible explanations of the complex crystallography of the natural uranyl hydroxides and the unusual behavior of polynuclear ions in hydrolyzed uranyl solutions.

  16. Production and Characterization of Desmalonichrome Relative Binding Affinity for Uranyl Ions in Relation to Other Siderophores

    Energy Technology Data Exchange (ETDEWEB)

    Mo, Kai-For; Dai, Ziyu; Wunschel, David S.

    2016-06-24

    Siderophores are Fe binding secondary metabolites that have been investigated for their uranium binding properties. Much of the previous work has focused on characterizing hydroxamate types of siderophores, such as desferrioxamine B, for their uranyl binding affinity. Carboxylate forms of these metabolites hold potential to be more efficient chelators of uranyl, yet they have not been widely studied and are more difficult to obtain. Desmalonichrome is a carboxylate siderophore which is not commercially available and so was obtained from the ascomycete fungus Fusarium oxysporum cultivated under Fe depleted conditions. The relative affinity for uranyl binding of desmalonichrome was investigated using a competitive analysis of binding affinities between uranyl acetate and different concentrations of iron(III) chloride using electrospray ionization mass spectrometry (ESI-MS). In addition to desmalonichrome, three other siderophores, including two hydroxamates (desferrioxamine B and desferrichrome) and one carboxylate (desferrichrome A) were studied to understand their relative affinities for the uranyl ion at two pH values. The binding affinities of hydroxymate siderophores to uranyl ion were found to decrease to a greater degree at lower pH as the concentration of Fe (III) ion increases. On the other hand, lowering pH has little impact on the binding affinities between carboxylate siderophores and uranyl ion. Desmalonichrome was shown to have the greatest relative affinity for uranyl at any pH and Fe(III) concentration. These results suggest that acidic functional groups in the ligands are critical for strong chelation with uranium at lower pH.

  17. Iron Chelation

    Science.gov (United States)

    Skip to main content Menu Donate Treatments Therapies Iron Chelation Iron chelation therapy is the main treatment ... have iron overload and need treatment. What is iron overload? Iron chelation therapy is used when you ...

  18. Imaging cancer using PET - the effect of the bifunctional chelator on the biodistribution of a {sup 64}Cu-labeled antibody

    Energy Technology Data Exchange (ETDEWEB)

    Dearling, Jason L.J., E-mail: jason.dearling@childrens.harvard.ed [Division of Nuclear Medicine and Department of Radiology, Children' s Hospital Boston, 300 Longwood Avenue, Boston, MA 02115 (United States); Harvard Medical School, Boston, MA 02115 (United States); Voss, Stephan D. [Division of Nuclear Medicine and Department of Radiology, Children' s Hospital Boston, 300 Longwood Avenue, Boston, MA 02115 (United States); Harvard Medical School, Boston, MA 02115 (United States); Dunning, Patricia; Snay, Erin [Division of Nuclear Medicine and Department of Radiology, Children' s Hospital Boston, 300 Longwood Avenue, Boston, MA 02115 (United States); Fahey, Frederic [Division of Nuclear Medicine and Department of Radiology, Children' s Hospital Boston, 300 Longwood Avenue, Boston, MA 02115 (United States); Harvard Medical School, Boston, MA 02115 (United States); Smith, Suzanne V. [Australian National Science and Technology Organisation (ANSTO), New Illawarra Road, PMB1, Menai, New South Wales 2234 (Australia); Huston, James S. [EMD Serono Research Center, 45A Middlesex Turnpike, Billerica, MA 01821-3936 (United States); Boston Biomedical Research Institute, Watertown, MA 02472-2899 (United States); Meares, Claude F. [Department of Chemistry, University of California, One Shields Avenue, Davis, CA 95616-5295 (United States); Treves, S. Ted; Packard, Alan B. [Division of Nuclear Medicine and Department of Radiology, Children' s Hospital Boston, 300 Longwood Avenue, Boston, MA 02115 (United States); Harvard Medical School, Boston, MA 02115 (United States)

    2011-01-15

    Introduction: Use of copper radioisotopes in antibody radiolabeling is challenged by reported loss of the radionuclide from the bifunctional chelator used to label the protein. The objective of this study was to investigate the relationship between the thermodynamic stability of the {sup 64}Cu-complexes of five commonly used bifunctional chelators (BFCs) and the biodistribution of an antibody labeled with {sup 64}Cu using these chelators in tumor-bearing mice. Methods: The chelators [S-2-(aminobenzyl)1,4,7-triazacyclononane-1,4,7-triacetic acid (p-NH{sub 2}-Bn-NOTA): 6-[p-(bromoacetamido)benzyl]-1, 4, 8, 11-tetraazacyclotetradecane-N, N', N'', N'''-tetraacetic acid (BAT-6): S-2-(4-aminobenzyl)-1,4,7,10-tetraazacyclododocane tetraacetic acid (p-NH{sub 2}-Bn-DOTA): 1,4,7,10-tetraazacyclododocane-N, N', N', N''-tetraacetic acid (DOTA): and 1-N-(4-aminobenzyl)-3,6,10,13,16,19-hexaazabicyclo[6.6.6]eicosane-1, 8-diamine (SarAr)] were conjugated to the anti-GD2 antibody ch14.18, and the modified antibody was labeled with {sup 64}Cu and injected into mice bearing subcutaneous human melanoma tumors (M21) (n = 3-5 for each study). Biodistribution data were obtained from positron emission tomography images acquired at 1, 24 and 48 hours post-injection, and at 48 hours post-injection a full ex vivo biodistribution study was carried out. Results: The biodistribution, including tumor targeting, was similar for all the radioimmunoconjugates. At 48 h post-injection, the only statistically significant differences in radionuclide uptake (p < 0.05) were between blood, liver, spleen and kidney. For example, liver uptake of [{sup 64}Cu]ch14.18-p-NH{sub 2}-Bn-NOTA was 4.74 {+-} 0.77 per cent of the injected dose per gram of tissue (%ID/g), and for [{sup 64}Cu]ch14.18-SarAr was 8.06 {+-} 0.77 %ID/g. Differences in tumor targeting correlated with variations in tumor size rather than which BFC was used. Conclusions: The results of this

  19. Standardization of methodology to derivatization and radiolabeling of the anti-CD20 monoclonal antibody from bifunctional chelator DOTA-NHS-Ester

    Energy Technology Data Exchange (ETDEWEB)

    Massicano, Adriana V.F.; Akanji, Akinkunmi G.; Santos, Josefina S.; Pujatti, Priscilla B.; Couto, Renata M.; Massicano, Felipe; Araujo, Elaine Bortoleti de [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil)], E-mail: adriana.avfernandes@gmail.com

    2009-07-01

    Lymphomas are cancers of the lymphatic system, being the most common the non-Hodgkin lymphoma (NHL). The Radioimmunotherapy (RIT), that increase the cytotoxic effect of monoclonal antibodies (mAb), therefore labeling these Mab with different radioisotopes. RIT combines the specificity of the antibody and the toxicity of the radionuclides. The mAb anti-CD20 is used for treatment of relapse or refractory NHL. The labeling of anti- CD20 with {sup 177}Lu, requires a bifunctional chelating agent that is designed to make a 'connect bridge' between the mAb and the radionuclide. The incorporation of the chelating group in mAb structure is called derivatization. The aim of this work is to study the derivatization of anti-CD20 antibody with DOTA-NHS-ester chelating group and labeling parameters to produce {sup 177}Lu-DOTA-Anti CD20. Five milligrams of anti-CD20 were purified by dialysis against phosphate buffer pH 8.0 and derivatized with DOTA-NHS-ester in 1:250, 1:500 and 1:1000 molar ratios. The reaction was conducted for 1 hour in gently mixing at room temperature and remained under refrigeration for 48 hours. The reaction mixture was purified in gel column Sephadex G-50 ; the aliquots that presented greater protein concentration, were mixed and concentrated. The purified antibody conjugated was added to 111-185MBq (3-5mCi) of {sup 177}LuCl3 diluted in 0.4 M acetate buffer pH 5.5. Radiochemical purity was less than 95% in all the molar ratios, indicating necessity of the purification after the labeling. The mAb derivatized showed stable when stored for to 1 month to 4 deg C and 4 days at -20 deg C. (author)

  20. Pretargeting of human mammary carcinoma xenografts with bispecific anti-MUC1/anti-Ga chelate antibodies and immunoscintigraphy with PET.

    Science.gov (United States)

    Schuhmacher, J; Klivényi, G; Kaul, S; Henze, M; Matys, R; Hauser, H; Clorius, J

    2001-10-01

    We recently demonstrated the feasibility of combining enhanced tumor-to-tissue contrast and PET imaging for immunoscintigraphic tumor localization in pancreas and colon carcinoma bearing nude mice. Contrast enhancement was obtained with a multistep targeting technique that consists of the sequential administration of an antitumor/antihapten bispecific antibody (BS-MAb), a blocker to saturate the antihapten binding sites of the BS-MAb that remains in circulation, and a low molecular weight Ga chelate, labeled with the positron emitter 68Ga, which serves as the hapten. To evaluate the efficacy of this pretargeting technique for breast cancer localization, we synthesized a BS-MAb from the F(ab')(2) fragments of the anti-MUC1 MAb 12H12 which reacts with the vast majority of human breast carcinomas, and the F(ab') fragment of an anti-Ga chelate MAb using a bifunctional chemical linker. The BS-MAb was tested for its affinity and its biokinetics in nude mice bearing a human mammary carcinoma. Equilibrium binding of the BS-MAb for mammary carcinoma cells was low (1.2 x 10(7) M(-1)) while the binding capacity of cells was high (8.4 x 10(6) BS-MAbs per cell). Tumor uptake of the 67Ga labeled chelate in pretargeted animals was to 5.8 +/- 0.8% iD/g resulting in a tumor-to-blood ratio of 2.6 at 1h postinjection. This compares with a ratio of 0.65 and 0.85 obtained with 125I-labeled native 12H12 at 24h and 48h postinjection. No difference in the tumor uptake of both the 68Ga and 67Ga labeled chelate was observed. PET imaging of mice, started 1h postinjection of the 68Ga chelate, clearly visualized all tumors.

  1. Pretargeting of human mammary carcinoma xenografts with bispecific anti-MUC1/anti-Ga chelate antibodies and immunoscintigraphy with PET

    Energy Technology Data Exchange (ETDEWEB)

    Schuhmacher, Jochen; Klivenyi, Gabor; Kaul, Sepp; Henze, Marcus; Matys, Ronald; Hauser, Harald; Clorius, John

    2001-10-01

    We recently demonstrated the feasibility of combining enhanced tumor-to-tissue contrast and PET imaging for immunoscintigraphic tumor localization in pancreas and colon carcinoma bearing nude mice. Contrast enhancement was obtained with a multistep targeting technique that consists of the sequential administration of an antitumor/antihapten bispecific antibody (BS-MAb), a blocker to saturate the antihapten binding sites of the BS-MAb that remains in circulation, and a low molecular weight Ga chelate, labeled with the positron emitter {sup 68}Ga, which serves as the hapten. To evaluate the efficacy of this pretargeting technique for breast cancer localization, we synthesized a BS-MAb from the F(ab'){sub 2} fragments of the anti-MUC1 MAb 12H12 which reacts with the vast majority of human breast carcinomas, and the F(ab') fragment of an anti-Ga chelate MAb using a bifunctional chemical linker. The BS-MAb was tested for its affinity and its biokinetics in nude mice bearing a human mammary carcinoma. Equilibrium binding of the BS-MAb for mammary carcinoma cells was low (1.2 x 10{sup 7} M{sup -1}) while the binding capacity of cells was high (8.4 x 10{sup 6} BS-MAbs per cell). Tumor uptake of the {sup 67}Ga labeled chelate in pretargeted animals was to 5.8 {+-} 0.8% iD/g resulting in a tumor-to-blood ratio of 2.6 at 1h postinjection. This compares with a ratio of 0.65 and 0.85 obtained with {sup 125}I-labeled native 12H12 at 24h and 48h postinjection. No difference in the tumor uptake of both the {sup 68}Ga and {sup 67}Ga labeled chelate was observed. PET imaging of mice, started 1h postinjection of the {sup 68}Ga chelate, clearly visualized all tumors.

  2. DOTA-functionalized polylysine: a high number of DOTA chelates positively influences the biodistribution of enzymatic conjugated anti-tumor antibody chCE7agl.

    Directory of Open Access Journals (Sweden)

    Jürgen Grünberg

    Full Text Available Site-specific enzymatic reactions with microbial transglutaminase (mTGase lead to a homogenous species of immunoconjugates with a defined ligand/antibody ratio. In the present study, we have investigated the influence of different numbers of 1,4,7,10-tetraazacyclododecane-N-N'-N''-N'''-tetraacetic acid (DOTA chelats coupled to a decalysine backbone on the in vivo behavior of the chimeric monoclonal anti-L1CAM antibody chCE7agl. The enzymatic conjugation of (DOTA1-decalysine, (DOTA3-decalysine or (DOTA5-decalysine to the antibody heavy chain (via Gln295/297 gave rise to immunoconjugates containing two, six or ten DOTA moieties respectively. Radiolabeling of the immunoconjugates with (177Lu yielded specific activities of approximately 70 MBq/mg, 400 MBq/mg and 700 MBq/mg with increasing numbers of DOTA chelates. Biodistribution experiments in SKOV3ip human ovarian cancer cell xenografts demonstrated a high and specific accumulation of radioactivity at the tumor site for all antibody derivatives with a maximal tumor accumulation of 43.6±4.3% ID/g at 24 h for chCE7agl-[(DOTA-decalysine]2, 30.6±12.0% ID/g at 24 h for chCE7agl-[(DOTA3-decalysine]2 and 49.9±3.1% ID/g at 48 h for chCE7agl-[(DOTA5-decalysine]2. The rapid elimination from the blood of chCE7agl-[(DOTA-decalysine]2 (1.0±0.1% ID/g at 24 h is associated with a high liver accumulation (23.2±4.6% ID/g at 24 h. This behavior changed depending on the numbers of DOTA moieties coupled to the decalysine peptide with a slower blood clearance (5.1±1.0 (DOTA3 versus 11.7±1.4% ID/g (DOTA5, p<0.005 at 24 h and lower radioactivity levels in the liver (21.4±3.4 (DOTA3 versus 5.8±0.7 (DOTA5, p<0.005 at 24 h. We conclude that the site-specific and stoichiometric uniform conjugation of the highly DOTA-substituted decalysine ((DOTA5-decalysine to an anti-tumor antibody leads to the formation of immunoconjugates with high specific activity and excellent in vivo behavior and is a valuable option for

  3. Purification of monoclonal antibodies, IgG1, from cell culture supernatant by use of metal chelate convective interaction media monolithic columns.

    Science.gov (United States)

    Rajak, Poonam; Vijayalakshmi, M A; Jayaprakash, N S

    2012-12-01

    Monoclonal antibodies (MAbs) have diverse applications in diagnostics and therapeutics. The recent advancement in hybridoma technology for large-scale production of MAbs in bioreactors demands rapid and efficient purification methods. Conventional affinity purification systems have drawbacks of low flow rates and denaturation of antibodies owing to harsh elution conditions. Here, we attempted purification of MAbs by use of a high-throughput metal-chelate methacrylate monolithic system. Monolithic macroporous convective interaction media-iminodiacetate (CIM-IDA) disks immobilized with four different metal ions (Cu²⁺, Ni²⁺, Zn²⁺ and Co²⁺) were used and evaluated for purification of anti-human serum albumin IgG1 mouse MAbs from cell culture supernatant after precipitation with 50% ammonium sulfate. Elution with 10 mM imidazole in the equilibration buffer (25 mM MMA = MOPS (Morpholino propane sulfonic acid) + MES (Morpholino ethane sulfonic acid) + Acetate + 0.5 M NaCl, pH 7.4) resulted in a purification of 25.7 ± 2.9-fold and 32.5 ± 2.6-fold in experiments done using Zn²⁺ and Co²⁺ metal ions, respectively. The highest recovery of 85.4 ± 1.0% was obtained with a CIM-IDA-Zn(II) column. SDS-PAGE, ELISA and immuno-blot showed that the antibodies recovered were pure, with high antigen-binding efficiency. Thus, metal chelate CIM monoliths could be a potential alternative to conventional systems for fast and efficient purification of MAbs from the complex cell culture supernatant.

  4. Click-chemistry strategy for labeling antibodies with copper-64 via a cross-bridged tetraazamacrocyclic chelator scaffold.

    Science.gov (United States)

    Kumar, Amit; Hao, Guiyang; Liu, Li; Ramezani, Saleh; Hsieh, Jer-Tsong; Öz, Orhan K; Sun, Xiankai

    2015-04-15

    We report a click-chemistry based modular strategy for antibody labeling with (64)Cu (t1/2 = 12.7 h; β(+) 0.656 MeV, 17.4%; β(-) 0.573 MeV, 39%; EC 43%) under ambient condition utilizing a cross-bridged tetraazamacrocyclic (CB-TE2A) analogue, which otherwise requires harsh conditions that make the CB-TE2A analogues under-utilized for protein labeling despite the fact that they form kinetically inert copper complexes with high in vivo stability. Our strategy involves prelabeling a CB-TE2A based scaffold (CB-TE2A-1C) with (64)Cu and its subsequent reaction with an antibody via the tetrazine-norbornene mediated click chemistry. The effectiveness of this strategy was demonstrated by labeling two monoclonal antibodies, an anti-PSMA antibody (YPSMA-1) and a chimeric anti-phosphatidylserine antibody (Bavituximab). The immunoreactivity of the antibodies remained unchanged after the tetrazine modification and click-chemistry (64)Cu labeling. To further demonstrate the practicality of the modular (64)Cu labeling strategy, we tested positron emission tomography (PET) imaging of tumor with the (64)Cu-labeled bavituximab in a mouse xenograft model. The tumor visualization and uptake of the labeled antibody exhibited the versatility of the click-chemistry strategy.

  5. Uranyl Oxalate Solubility

    Energy Technology Data Exchange (ETDEWEB)

    Leturcq, G.; Costenoble, S.; Grandjean, S. [CEA Marcoule DEN/DRCP/SCPS/LCA - BP17171 - 30207 Bagnols sur Ceze cedex (France)

    2008-07-01

    The solubility of uranyl oxalate was determined at ambient temperature by precipitation in oxalic-nitric solutions, using an initial uranyl concentration of 0.1 mol/L. Oxalic concentration varied from 0.075 to 0.3 mol/L while nitric concentration ranged between 0.75 and 3 mol/L. Dissolution tests, using complementary oxalic-nitric media, were carried out for 550 hours in order to study the kinetic to reach thermodynamic equilibrium. Similar solubility values were reached by dissolution and precipitation. Using the results, it was possible to draw the solubility surface versus oxalic and nitric concentrations and to determine both the apparent solubility constant of UO{sub 2}C{sub 2}O{sub 4}, 3H{sub 2}O (Ks) and the apparent formation constant of the first uranyl-oxalate complex UO{sub 2}C{sub 2}O{sub 4} (log {beta}1), for ionic strengths varying between 1 and 3 mol/L. Ks and log {beta}1 values were found to vary from 1.9 10{sup -8} to 9.2 10{sup -9} and from 5.95 to 6.06, respectively, when ionic strength varied from 1 to 3 mol/L. A second model may fit our data obtained at an ionic strength of 3 mol/L suggesting as reported by Moskvin et al. (1959) that no complexes are formed for [H{sup +}] at 3 M. The Ks value would then be 1.3 10{sup -8}. (authors)

  6. Novel enterobactin analogues as potential therapeutic chelating agents: Synthesis, thermodynamic and antioxidant studies

    Science.gov (United States)

    Zhang, Qingchun; Jin, Bo; Shi, Zhaotao; Wang, Xiaofang; Liu, Qiangqiang; Lei, Shan; Peng, Rufang

    2016-09-01

    A series of novel hexadentate enterobactin analogues, which contain three catechol chelating moieties attached to different molecular scaffolds with flexible alkyl chain lengths, were prepared. The solution thermodynamic stabilities of the complexes with uranyl, ferric(III), and zinc(II) ions were then investigated. The hexadentate ligands demonstrate effective binding ability to uranyl ion, and the average uranyl affinities are two orders of magnitude higher than 2,3-dihydroxy-N1,N4-bis[(1,2-hydroxypyridinone-6-carboxamide)ethyl]terephthalamide [TMA(2Li-1,2-HOPO)2] ligand with similar denticity. The high affinity of hexadentate ligands could be due to the presence of the flexible scaffold, which favors the geometric agreement between the ligand and the uranyl coordination preference. The hexadentate ligands also exhibit higher antiradical efficiency than butylated hydroxyanisole (BHA). These results provide a basis for further studies on the potential applications of hexadentate ligands as therapeutic chelating agents.

  7. Using lanthanide chelates and uranyl compounds for diagnostic by fluoroimmunoassays

    Energy Technology Data Exchange (ETDEWEB)

    Santos, Elen G.; Tomiyama, Claudia S.; Kodaira, Claudia A.; Felinto, Maria C.F.C., E-mail: mfelinto@ipen.b [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil); Lourenco, Ana V. S.; Brito, Hermi F., E-mail: hefbrito@iq.usp.b [Universidade de Sao Paulo (USP), SP (Brazil). Inst. de Quimica. Lab. de Elementos do Bloco f; Brito, Maria E.F., E-mail: britomef@cpqam.fiocruz.b [Centro de Pesquisas Aggeu Magalhaes (CPqAM/Fiocruz), Recife, PE (Brazil)

    2009-07-01

    The importance of the luminescence of lanthanide ions and UO{sub 2}{sup 2+} is related to its peculiar characteristics, e.g. long lifetime and line-like emission bands in the visible, which make these ions unique among the species that are known to luminescence. Recent developments in the field of supramolecular chemistry have allowed the design of ligands capable of encapsulating lanthanide ions, thus forming kinetically inert complexes. By introduction of chromophoric groups in these ligands, an intense luminescence of the ion can be obtained via the 'antenna effect', defined as a light conversion process involving distinct absorbing (ligand) and emitting (metal ion) components. In such a process, the quantities that contribute to the luminescence intensity are the efficiency of the absorption, the efficiency of the ligand-metal energy transfer, and the efficiency of the metal luminescence. Encapsulation of lanthanide ions with suitable ligands may therefore give rise to 'molecular devices' capable to emit strong, long-lived luminescence. Besides the intrinsic interest in their excited state properties, compounds of lanthanide ions, in particular of the Eu{sup 3+} and Tb{sup 3+} ions, and now UO{sub 2}{sup 2+} are important for their potential use as luminescent labels for biological species in fluoroimmunoassays (FIAs). This is most interesting because fluorimetric labeling represents an alternative method to the use of radioactive labels, which has long been the most common way of quantifying immunoreactions. In this article we report information about luminescent materials, which gave a good signal to quantify biological molecules by TR-FIA, DELFIA , DSLFIA, RIA and FRET. (author)

  8. p-Isothiocyanatobenzyl-desferrioxamine: a new bifunctional chelate for facile radiolabeling of monoclonal antibodies with zirconium-89 for immuno-PET imaging

    Energy Technology Data Exchange (ETDEWEB)

    Perk, Lars R.; Vosjan, Maria J.W.D.; Budde, Marianne [VU University Medical Center, Department of Otolaryngology/Head and Neck Surgery, De Boelelaan 1117, PO Box 7057, MB, Amsterdam (Netherlands); Visser, Gerard W.M. [VU University Medical Center, Nuclear Medicine and PET Research, Amsterdam (Netherlands); Jurek, Paul; Kiefer, Garry E. [Macrocyclics Inc., Dallas, TX (United States); Dongen, Guus A.M.S. van [VU University Medical Center, Department of Otolaryngology/Head and Neck Surgery, De Boelelaan 1117, PO Box 7057, MB, Amsterdam (Netherlands); VU University Medical Center, Nuclear Medicine and PET Research, Amsterdam (Netherlands)

    2010-02-15

    Immuno-PET is an emerging imaging tool for the selection of high potential antibodies (mAbs) for imaging and therapy. The positron emitter zirconium-89 ({sup 89}Zr) has attractive characteristics for immuno-PET with intact mAbs. Previously, we have described a multi-step procedure for stable coupling of {sup 89}Zr to mAbs via the bifunctional chelate (BFC) tetrafluorophenol-N-succinyldesferal (TFP-N-sucDf). To enable widespread use of {sup 89}Zr-immuno-PET, we now introduce the novel BFC p-isothiocyanatobenzyl-desferrioxamine B (Df-Bz-NCS) and compare its performance in {sup 89}Zr-immuno-PET with the reference BFC TFP-N-sucDf. Three mAbs were premodified with Df-Bz-NCS and labeled with {sup 89}Zr at different pHs to assess the reaction kinetics and robustness of the radiolabeling. Stability of both {sup 89}Zr-Df-Bz-NCS- and {sup 89}Zr-N-sucDf-conjugates was evaluated in different buffers and human serum. Comparative biodistribution and PET studies in tumor-bearing mice were undertaken. The selected conjugation conditions resulted in a chelate:mAb substitution ratio of about 1.5:1. Under optimal radiolabeling conditions (pH between 6.8-7.2), the radiochemical yield was >85% after 60 min incubation at room temperature, resulting in radioimmunoconjugates with preserved integrity and immunoreactivity. The new radioimmunoconjugate was very stable in serum for up to 7 days at 37 C, with <5% {sup 89}Zr release, and was equally stable compared to the reference conjugate when stored in the appropriate buffer at 4 C. In biodistribution and imaging experiments, the novel and the reference radioimmunoconjugates showed high and similar accumulation in tumors in nude mice. The novel Df-Bz-NCS BFC allows efficient and easy preparation of optimally performing {sup 89}Zr-labeled mAbs, facilitating further exploration of {sup 89}Zr-immuno-PET as an imaging tool. (orig.)

  9. Role of chelates in treatment of cancer

    Directory of Open Access Journals (Sweden)

    Tripathi Laxmi

    2007-01-01

    Full Text Available Chelates are used in cancer as cytotoxic agent, as radioactive agent in imaging studies and in radioimmunotherapy. Various chelates based on ruthenium, copper, zinc, organocobalt, gold, platinum, palladium, cobalt, nickel and iron are reported as cytotoxic agent. Monoclonal antibodies labeled with radioactive metals such as yttrium-90, indium-111 and iodine-131 are used in radioimmunotherapy. This review is an attempt to compile the use of chelates as cytotoxic drugs and in radioimmunotherapy.

  10. Optical apparatus and method for sensing uranyl

    Science.gov (United States)

    Baylor, L.C.; Buchanan, B.R.

    1994-01-01

    An optical sensing device for uranyl and other substances, a method for making an optical sensing device and a method for chemically binding uranyl and other indicators to glass, quartz, cellulose and similar substrates. The indicator, such as arsenazo III, is immobilized on the substrate using a chemical binding process. The immobilized arsenazo III causes uranyl from a fluid sample to bind irreversibly to the substrate at its active sites, thus causing absorption of a portion of light transmitted through the substrate. Determination of the amount of light absorbed, using conventional means, yields the concentration of uranyl present in the sample fluid. The binding of uranyl on the substrate can be reversed by subsequent exposure of the substrate to a solution of 2,6-pyridinedicarboxylic acid. The chemical binding process is suitable for similarly binding other indicators, such as bromocresol green.

  11. Antibody

    Science.gov (United States)

    An antibody is a protein produced by the body's immune system when it detects harmful substances, called antigens. Examples ... microorganisms (bacteria, fungi, parasites, and viruses) and chemicals. Antibodies may be produced when the immune system mistakenly ...

  12. Oral iron chelators.

    Science.gov (United States)

    Kwiatkowski, Janet L

    2010-02-01

    Effective chelation therapy can prevent or reverse organ toxicity related to iron overload, yet cardiac complications and premature death continue to occur, largely related to difficulties with compliance in patients who receive parenteral therapy. The use of oral chelators may be able to overcome these difficulties and improve patient outcomes. A chelator's efficacy at cardiac and liver iron removal and side-effect profile should be considered when tailoring individual chelation regimens. Broader options for chelation therapy, including possible combination therapy, should improve clinical efficacy and enhance patient care.

  13. Uranyl Sequestration: Synthesis and Structural Characterization of Uranyl Complexes with a Tetradentate Methylterephthalamide Ligand

    Energy Technology Data Exchange (ETDEWEB)

    Ni, Chengbao; Shuh, David; Raymond, Kenneth

    2011-03-07

    Uranyl complexes of a bis(methylterephthalamide) ligand (LH{sub 4}) have been synthesized and characterized by X-ray crystallography. The structure is an unexpected [Me{sub 4}N]{sub 8}[L(UO{sub 2})]{sub 4} tetramer, formed via coordination of the two MeTAM units of L to two uranyl moieties. Addition of KOH to the tetramer gave the corresponding monomeric uranyl methoxide species [Me{sub 4}N]K{sub 2}[LUO{sub 2}(OMe)].

  14. Syntheses and structures of uranyl ethylenediphosphonates: from layers to elliptical nanochannels.

    Science.gov (United States)

    Tian, Tao; Yang, Weiting; Wang, Hao; Dang, Song; Pan, Qing-Jiang; Sun, Zhong-Ming

    2013-06-17

    A family of uranium diphosphonates have been hydrothermally synthesized through the reaction of ethylenediphosphonic acid (EDP, H4L) and uranyl nitrate/zinc uranyl acetate in the presence of organic templates, such as tetraethyl ammonium (NEt4(+)), 4,4'-bipyridine (bipy), and 1,10-phenanthroline (phen). The UO2(2+) in UO2(H2O)(H2L)(EDP-U1) is equatorially five-coordinated by four phosphonate groups and one aqua ligand, forming a pentagonal bipyramid. Each EDP ligand is doubly protonated and chelates three UO2(2+), resulting in a layered structure. Compounds (NEt4)2(UO2)3(HL)2(H2L)·4H2O (EDP-U2) and (H2bipy)UO2L (EDP-U3) have the same layered structure in which NEt4(+) and protonated bipy fill in the uranyl-phosphonate interlayers, respectively, and play a role to balance the negative charges. Different from that in EDP-U1, the UO2(2+) exists in the form of a UO6 tetragonal bipyramid and is surrounded by four different EDP ligands in EDP-U2 and EDP-U3. (Hphen)2(UO2)2(H2L)3 (EDP-U4) features a three-dimensional framework structure with large elliptical channels along the c axis (1.3 × 1.1 nm(2)). Monoprotonated phen molecules fill in these channels and hold together through strong π···π interactions. All of the four compounds have been characterized by IR and photoluminescent spectroscopy. Their characteristic emissions have been attributed as transition properties of uranyl cations. The ion-exchange study indicates that [Co(en)3](3+) could partially replace the protonated phen molecules.

  15. Chelation in Metal Intoxication

    Directory of Open Access Journals (Sweden)

    Swaran J.S. Flora

    2010-06-01

    Full Text Available Chelation therapy is the preferred medical treatment for reducing the toxic effects of metals. Chelating agents are capable of binding to toxic metal ions to form complex structures which are easily excreted from the body removing them from intracellular or extracellular spaces. 2,3-Dimercaprol has long been the mainstay of chelation therapy for lead or arsenic poisoning, however its serious side effects have led researchers to develop less toxic analogues. Hydrophilic chelators like meso-2,3-dimercaptosuccinic acid effectively promote renal metal excretion, but their ability to access intracellular metals is weak. Newer strategies to address these drawbacks like combination therapy (use of structurally different chelating agents or co-administration of antioxidants have been reported recently. In this review we provide an update of the existing chelating agents and the various strategies available for the treatment of heavy metals and metalloid intoxications.

  16. The Influence of Linker Geometry on Uranyl Complexation by Rigidly-Linked Bis(3-hydroxy-N-methyl-pyridin-2-one)

    Energy Technology Data Exchange (ETDEWEB)

    Szigethy, Geza; Raymond, Kenneth

    2010-04-22

    A series of bis(3-hydroxy-N-methyl-pyridin-2-one) ligands was synthesized, and their respective uranyl complexes were characterized by single crystal X-ray diffraction analyses. These structures were inspected for high-energy conformations and evaluated using a series of metrics to measure co-planarity of chelating moieties with each other and the uranyl coordination plane, as well as to measure coordinative crowding about the uranyl dication. Both very short (ethyl, 3,4-thiophene and o-phenylene) and very long ({alpha},{alpha}{prime}-m-xylene and 1,8-fluorene) linkers provide optimal ligand geometries about the uranyl cation, resulting in planar, unstrained molecular arrangements. The planarity of the rigid linkers also suggests there is a degree of pre-organization for a planar coordination mode that is ideal for uranyl-selective ligand design. Comparison of intramolecular N{sub amide}-O{sub phenolate} distances and {sup 1}H NMR chemical shifts of amide protons supports earlier results that short linkers provide the optimal geometry for intramolecular hydrogen bonding.

  17. Solid-state dynamics of uranyl polyoxometalates.

    Science.gov (United States)

    Alam, Todd M; Liao, Zuolei; Zakharov, Lev N; Nyman, May

    2014-07-01

    Understanding fundamental uranyl polyoxometalate (POM) chemistry in solution and the solid state is the first step to defining its future role in the development of new actinide materials and separation processes that are vital to every step of the nuclear fuel cycle. Many solid-state geometries of uranyl POMs have been described, but we are only beginning to understand their chemical behavior, which thus far includes the role of templates in their self-assembly, and the dynamics of encapsulated species in solution. This study provides unprecedented detail into the exchange dynamics of the encapsulated species in the solid state through Magic Angle Spinning Nuclear Magnetic Resonance (MAS NMR) spectroscopy. Although it was previously recognized that capsule-like molybdate and uranyl POMs exchange encapsulated species when dissolved in water, analogous exchange in the solid state has not been documented, or even considered. Here, we observe the extremely high rate of transport of Li(+) and aqua species across the uranyl shell in the solid state, a process that is affected by both temperature and pore blocking by larger species. These results highlight the untapped potential of emergent f-block element materials and vesicle-like POMs.

  18. Stoichiometry of uranyl salophene anion complexes

    NARCIS (Netherlands)

    Antonisse, Martijn M.G.; Snellink-Ruel, Bianca H.M.; Engbersen, Johan F.J.; Reinhoudt, David N.

    1998-01-01

    In PVC/NPOE ion-selective membranes of potentiometric sensors, the guest-host stoichiometry of the anion complex of H2PO4 - and F- selective uranyl salophene derivatives is 2:1. This stoichiometry is different from the stoichiometry observed in DMSO solution (1H NMR) or solid state (X-ray crystal st

  19. The Chelate Effect Redefined.

    Science.gov (United States)

    da Silva, J. J. R. Frausto

    1983-01-01

    Discusses ambiguities of the accepted definition of the chelate effect, suggesting that it be defined in terms of experimental observation rather than mathematical abstraction. Indicates that the effect depends on free energy change in reaction, ligand basicity, pH of medium, type of chelates formed, and concentration of ligands in solution. (JN)

  20. Expanding the crystal chemistry of uranyl peroxides: four hybrid uranyl-peroxide structures containing EDTA.

    Science.gov (United States)

    Qiu, Jie; Ling, Jie; Sieradzki, Claire; Nguyen, Kevin; Wylie, Ernest M; Szymanowski, Jennifer E S; Burns, Peter C

    2014-11-17

    The first four uranyl peroxide compounds containing ethylenediaminetetra-acetate (EDTA) were synthesized and characterized from aqueous uranyl peroxide nitrate solutions with a pH range of 5-7. Raman spectra demonstrated that reaction solutions that crystallized [NaK15[(UO2)8(O2)8(C10H12O10N2)2(C2O4)4]·(H2O)14] (1) and [Li4K6[(UO2)8(O2)6(C10H12O10N2)2(NO3)6]·(H2O)26] (2) contained excess peroxide, and their structures contained oxidized ethylenediaminetetraacetate, EDTAO2(4-). The solutions from which [K4[(UO2)4(O2)2(C10H13O8N2)2(IO3)2]·(H2O)16] (3) and LiK3[(UO2)4(O2)2(C10H12O8N2)2(H2O)2]·(H2O)18 (4) crystallized contained no free peroxide, and the structures incorporated intact EDTA(4-). In contrast to the large family of uranyl peroxide cage clusters, coordination of uranyl peroxide units in 1-4 by EDTA(4-) or EDTAO2(4-) results in isolated tetramers or dimers of uranyl ions that are bridged by bidentate peroxide groups. Two tetramers are bridged by EDTAO2(4-) to form octamers in 1 and 2, and dimers of uranyl polyhedra are linked through iodate groups in 3 and EDTA(4-) in 4, forming chains in both cases. In each structure the U-O2-U dihedral angle is strongly bent, at ∼140°, consistent with the configuration of this linkage in cage clusters and other recently reported uranyl peroxides.

  1. Micro-SHINE Uranyl Sulfate Irradiations at the Linac

    Energy Technology Data Exchange (ETDEWEB)

    Youker, Amanda J. [Argonne National Lab. (ANL), Argonne, IL (United States); Kalensky, Michael [Argonne National Lab. (ANL), Argonne, IL (United States); Chemerisov, Sergey [Argonne National Lab. (ANL), Argonne, IL (United States); Schneider, John [Argonne National Lab. (ANL), Argonne, IL (United States); Byrnes, James [Argonne National Lab. (ANL), Argonne, IL (United States); Vandegrift, George F. [Argonne National Lab. (ANL), Argonne, IL (United States)

    2016-08-01

    Peroxide formation due to water radiolysis in a uranyl sulfate solution is a concern for the SHINE Medical Technologies process in which Mo-99 is generated from the fission of dissolved low enriched uranium. To investigate the effects of power density and fission on peroxide formation and uranyl-peroxide precipitation, uranyl sulfate solutions were irradiated using a 50-MeV electron linac as part of the micro-SHINE experimental setup. Results are given for uranyl sulfate solutions with both high and low enriched uranium irradiated at different linac powers.

  2. Chelating polymeric membranes

    KAUST Repository

    Peinemann, Klaus-Viktor

    2015-01-22

    The present application offers a solution to the current problems associated with recovery and recycling of precious metals from scrap material, discard articles, and other items comprising one or more precious metals. The solution is premised on a microporous chelating polymeric membrane. Embodiments include, but are not limited to, microporous chelating polymeric membranes, device comprising the membranes, and methods of using and making the same.

  3. Computer simulation of uranyl uptake by the rough lipopolysaccharide membrane of Pseudomonas aeruginosa.

    Science.gov (United States)

    Lins, Roberto D; Vorpagel, Erich R; Guglielmi, Matteo; Straatsma, T P

    2008-01-01

    Heavy metal environmental contaminants cannot be destroyed but require containment, preferably in concentrated form, in a solid or immobile form for recycling or final disposal. Microorganisms are able to take up and deposit high levels of contaminant metals, including radioactive metals such as uranium and plutonium, into their cell wall. Consequently, these microbial systems are of great interest as the basis for potential environmental bioremediation technologies. The outer membranes of Gram-negative microbes are highly nonsymmetric and exhibit a significant electrostatic potential gradient across the membrane. This gradient has a significant effect on the uptake and transport of charged and dipolar compounds. However, the effectiveness of microbial systems for environmental remediation will depend strongly on specific properties that determine the uptake of targeted contaminants by a particular cell wall. To aid in the design of microbial remediation technologies, knowledge of the factors that determine the affinity of a particular bacterial outer membrane for the most common ionic species found in contaminated soils and groundwater is of great importance. Using our previously developed model for the lipopolysaccharide (LPS) membrane of Pseudomonas aeruginosa, this work presents the potentials of mean force as the estimate of the free energy profile for uptake of sodium, calcium, chloride, uranyl ions, and a water molecule by the bacterial LPS membrane. A compatible classical parameter set for uranyl has been developed and validated. Results show that the uptake of uranyl is energetically a favorable process relative to the other ions studied. At neutral pH, this nuclide is shown to be retained on the surface of the LPS membrane through chelation with the carboxyl and hydroxyl groups located in the outer core.

  4. DNA conformational analysis in solution by uranyl mediated photocleavage

    DEFF Research Database (Denmark)

    Nielsen, Peter E.; Møllegaard, N E; Jeppesen, C

    1990-01-01

    by uranyl in a way indicating strongest uranyl binding at the center of the minor groove of the AT-region. The A-tracts of kinetoplast DNA show the highest reactivity at the 3'-end of the tract--as opposed to cleavage by EDTA/Fell--in accordance with the minor groove being more narrow at this end. Finally...

  5. Chelation Therapy for Mercury Poisoning

    Directory of Open Access Journals (Sweden)

    Rong Guan

    2009-01-01

    Full Text Available Chelation therapy has been the major treatment for heavy metal poisoning. Various chelating agents have been developed and tested for treatment of heavy metal intoxications, including mercury poisoning. It has been clearly shown that chelating agents could rescue the toxicity caused by heavy metal intoxication, but the potential preventive role of chelating agents against heavy metal poisoning has not been explored much. Recent paper by Siddiqi and colleagues has suggested a protective role of chelating agents against mercury poisoning, which provides a promising research direction for broader application of chelation therapy in prevention and treatment of mercury poisoning.

  6. Structure and spectroscopy of uranyl salicylaldiminate complexes

    Energy Technology Data Exchange (ETDEWEB)

    Tamasi, A.L.; Barnes, C.L.; Walensky, J.R. [Missouri Univ., Columbia, MO (United States). Dept. of Chemistry

    2013-07-01

    The synthesis of uranyl complexes coordinated to tridentate, monoanionic salicylaldiminate (Schiff base) ligands was achieved by the reaction of UO{sub 2}Cl{sub 2}(THF){sub 3}, 1, with one equivalent of the corresponding sodium salicylaldiminate salts affording [(C{sub 9}H{sub 6}N)N=C(H)C{sub 6}H{sub 2}'Bu{sub 2}O]UO{sub 2}Cl(THF), 2, [(NC{sub 5}H{sub 4})N=C(H)C{sub 6}H{sub 2}'Bu{sub 2}O]UO{sub 2}Cl(THF), 3, and [(C{sub 6}H{sub 4}SCH{sub 3})N=C(H)C{sub 6}H{sub 2}'Bu{sub 2}O]UO{sub 2}Cl(THF), 4. These are uncommon examples of uranyl complexes with a monoanionic ancillary ligand to stabilize the coordination sphere and one chloride ligand. Compounds 2-4 have been characterized by {sup 1}H and {sup 13}C NMR spectroscopy as well as IR and UVVis spectroscopy and their structures determined by X-ray crystallography. (orig.)

  7. Chelation Therapy for Mercury Poisoning

    OpenAIRE

    Rong Guan; Han Dai

    2009-01-01

    Chelation therapy has been the major treatment for heavy metal poisoning. Various chelating agents have been developed and tested for treatment of heavy metal intoxications, including mercury poisoning. It has been clearly shown that chelating agents could rescue the toxicity caused by heavy metal intoxication, but the potential preventive role of chelating agents against heavy metal poisoning has not been explored much. Recent paper by Siddiqi and colleagues has suggested a protective role o...

  8. Uranyl-oxo coordination directed by non-covalent interactions.

    Science.gov (United States)

    Lewis, Andrew J; Yin, Haolin; Carroll, Patrick J; Schelter, Eric J

    2014-07-28

    Directed coordination of weakly Lewis acidic K(+) ions to weakly Lewis basic uranyl oxo ligands is accomplished through non-covalent cation-π and cation-F interactions for the first time. Comparison of a family of structurally related diarylamide ligands highlights the role that the cation-π and cation-F interactions play in guiding coordination. Cation binding to uranyl is demonstrated in the solid state and in solution, providing the shortest reported crystallographic uranyl-oxo to potassium distance. UV-Vis, TD-DFT calculations, and electrochemical measurements show that cation coordination directly impacts the electronics at the uranium(vi) cation.

  9. Chelated minerals for poultry

    Directory of Open Access Journals (Sweden)

    SL Vieira

    2008-06-01

    Full Text Available Organic minerals have been subject of an increasing number of investigations recently. These compounds can be considered the most significant event regarding commercial forms of minerals targeting animal supplementation in the last decades. Minerals, especially metals, are usually supplemented in poultry feeds using cheap saline sources and have never required a lot of attention in terms of quality. On the other hand, definitions of organic minerals are very broad and frequently lead to confusion when decision-making becomes necessary. Organic minerals include any mineral bound to organic compounds, regardless of the type of existing bond between mineral and organic molecules. Proteins and carbohydrates are the most frequent candidates in organic mineral combinations. Organic fraction size and bond type are not limitations in organic mineral definition; however, essential metals (Cu, Fe, Zn, and Mn can form coordinated bonds, which are stable in intestinal lumen. Metals bound to organic ligands by coordinated bonds can dissociate within animal metabolism whereas real covalent bonds cannot. Chelated minerals are molecules that have a metal bound to an organic ligand through coordinated bonds; but many organic minerals are not chelates or are not even bound through coordinated bonds. Utilization of organic minerals is largely dependent on the ligand; therefore, amino acids and other small molecules with facilitated access to the enterocyte are supposed to be better utilized by animals. Organic minerals with ligands presenting long chains may require digestion prior to absorption. After absorption, organic minerals may present physiological effects, which improve specific metabolic responses, such as the immune response. Many studies have demonstrated the benefits of metal-amino acid chelates on animal metabolism, but the detection positive effects on live performance is less consistent.

  10. Modulation of the Structure and Properties of Uranyl Ion Coordination Polymers Derived from 1,3,5-Benzenetriacetate by Incorporation of Ag(I) or Pb(II).

    Science.gov (United States)

    Thuéry, Pierre; Harrowfield, Jack

    2016-07-01

    Reaction of uranyl nitrate with 1,3,5-benzenetriacetic acid (H3BTA) in the presence of additional species, either organic bases or their conjugate acids or metal cations, has provided 12 new crystalline complexes, all but one obtained under solvo-hydrothermal conditions. The complexes [C(NH2)3][UO2(BTA)]·H2O (1) and [H2NMe2][UO2(BTA)] (2) crystallize as one- or two-dimensional (1D or 2D) assemblies, respectively, both with uranyl tris-chelation by carboxylate groups and hydrogen-bonded counterions but different ligand conformations. One of the bound carboxylate units is replaced by chelating 1,10-phenanthroline (phen) or 3,4,7,8-tetramethyl-1,10-phenanthroline (Me4phen) in the complexes [(UO2)3(BTA)2(phen)3]·4H2O (3) and [(UO2)3(BTA)2(Me4phen)3]·NMP·3H2O (4) (NMP = N-methyl-2-pyrrolidone), which are a 2D network with honeycomb topology and a 1D polymer, respectively. With silver(I) cations, [UO2Ag(BTA)] (5), a three-dimensional (3D) framework in which the ligand assumes various chelating/bridging coordination modes, and the aromatic ring is involved in Ag(I) bonding, is obtained. A series of seven heterometallic complexes results when lead(II) cations and N-chelating molecules are both present. The complexes [UO2Pb(BTA)(NO3)(bipy)] (6) and [UO2Pb2(BTA)2(bipy)2]·3H2O (7), where bipy is 2,2'-bipyridine, crystallize from the one solution, as 1D and 2D assemblies, respectively. The two 1D coordination polymers [UO2Pb(BTA)(HCOO)(phen)] (8 and 9), again obtained from the one synthesis, provide an example of coordination isomerism, with the formate anion bound either to lead(II) or to uranyl cations. Another 2D architecture is found in [(UO2)2Pb2(BTA)2(HBTA)(H2O)2(phen)2]·2H2O (10), which provides a possible example of a Pb-oxo(uranyl) "cation-cation" interaction. While [UO2Pb(BTA)(HCOO)0.5(NO3)0.5(Me2phen)] (11), where Me2phen is 5,6-dimethyl-1,10-phenanthroline, is a 1D assembly close to those in 6 and 8, [UO2Pb2(BTA)2(Me4phen)2] (12), obtained together with

  11. Surface complexation model of uranyl sorption on Georgia kaolinite

    Science.gov (United States)

    Payne, T.E.; Davis, J.A.; Lumpkin, G.R.; Chisari, R.; Waite, T.D.

    2004-01-01

    The adsorption of uranyl on standard Georgia kaolinites (KGa-1 and KGa-1B) was studied as a function of pH (3-10), total U (1 and 10 ??mol/l), and mass loading of clay (4 and 40 g/l). The uptake of uranyl in air-equilibrated systems increased with pH and reached a maximum in the near-neutral pH range. At higher pH values, the sorption decreased due to the presence of aqueous uranyl carbonate complexes. One kaolinite sample was examined after the uranyl uptake experiments by transmission electron microscopy (TEM), using energy dispersive X-ray spectroscopy (EDS) to determine the U content. It was found that uranium was preferentially adsorbed by Ti-rich impurity phases (predominantly anatase), which are present in the kaolinite samples. Uranyl sorption on the Georgia kaolinites was simulated with U sorption reactions on both titanol and aluminol sites, using a simple non-electrostatic surface complexation model (SCM). The relative amounts of U-binding >TiOH and >AlOH sites were estimated from the TEM/EDS results. A ternary uranyl carbonate complex on the titanol site improved the fit to the experimental data in the higher pH range. The final model contained only three optimised log K values, and was able to simulate adsorption data across a wide range of experimental conditions. The >TiOH (anatase) sites appear to play an important role in retaining U at low uranyl concentrations. As kaolinite often contains trace TiO2, its presence may need to be taken into account when modelling the results of sorption experiments with radionuclides or trace metals on kaolinite. ?? 2004 Elsevier B.V. All rights reserved.

  12. Antithyroglobulin antibody

    Science.gov (United States)

    Thyroglobulin antibody; Thyroiditis - thyroglobulin antibody; Hypothyroidism - thyroglobulin antibody; Thyroiditis - thyroglobulin antibody; Graves disease - thyroglobulin antibody; Underactive thyroid - thyroglobulin antibody

  13. A Phosphorylation Tag for Uranyl Mediated Protein Purification and Photo Assisted Tag Removal

    DEFF Research Database (Denmark)

    Zhang, Qiang; Jørgensen, Thomas. J. D.; Nielsen, Peter E;

    2014-01-01

    enables target protein purification from an E. coli extract by immobilized uranyl affinity chromatography. Subsequently, the tag can be efficiently removed by UV-irradiation assisted uranyl photocleavage. We therefore suggest that the divalent uranyl ion (UO22+) may provide a dual function in protein...

  14. The catalytic role of uranyl in formation of polycatechol complexes

    Directory of Open Access Journals (Sweden)

    Halada Gary P

    2011-03-01

    Full Text Available Abstract To better understand the association of contaminant uranium with natural organic matter (NOM and the fate of uranium in ground water, spectroscopic studies of uranium complexation with catechol were conducted. Catechol provides a model for ubiquitous functional groups present in NOM. Liquid samples were analyzed using Raman, FTIR, and UV-Vis spectroscopy. Catechol was found to polymerize in presence of uranyl ions. Polymerization in presence of uranyl was compared to reactions in the presence of molybdate, another oxyion, and self polymerization of catechol at high pH. The effect of time and dissolved oxygen were also studied. It was found that oxygen was required for self-polymerization at elevated pH. The potential formation of phenoxy radicals as well as quinones was monitored. The benzene ring was found to be intact after polymerization. No evidence for formation of ether bonds was found, suggesting polymerization was due to formation of C-C bonds between catechol ligands. Uranyl was found to form outer sphere complexes with catechol at initial stages but over time (six months polycatechol complexes were formed and precipitated from solution (forming humic-like material while uranyl ions remained in solution. Our studies show that uranyl acts as a catalyst in catechol-polymerization.

  15. Macroreticular chelating ion-exchangers.

    Science.gov (United States)

    Hirsch, R F; E Gancher, R; Russo, F R

    1970-06-01

    Two macroreticular chelating ion-exchangers have been prepared and characterized. One contains the iminodiacetate group and the second contains the arsonate group as the ion-exchanging site. The macroreticular resins show selectivities among metal ions similar to those of the commercially available naicroreticular chelating resins. Chromatographie separations on the new resins are rapid and sharp.

  16. Rate theory on water exchange in aqueous uranyl ion

    Science.gov (United States)

    Dang, Liem X.; Vo, Quynh N.; Nilsson, Mikael; Nguyen, Hung D.

    2017-03-01

    We report a classical rate theory approach to predict the exchange mechanism that occurs between water and aqueous uranyl ion. Using our water and ion-water polarizable force field and molecular dynamics techniques, we computed the potentials of mean force for the uranyl ion-water pair as a function of different pressures at ambient temperature. These potentials of mean force were used to calculate rate constants using transition rate theory; the transmission coefficients also were examined using the reactive flux method and Grote-Hynes approach. The computed activation volumes are positive; thus, the mechanism of this particular water-exchange is a dissociative process.

  17. Gas Phase Reactions of Ions Derived from Anionic Uranyl Formate and Uranyl Acetate Complexes

    Science.gov (United States)

    Perez, Evan; Hanley, Cassandra; Koehler, Stephen; Pestok, Jordan; Polonsky, Nevo; Van Stipdonk, Michael

    2016-12-01

    The speciation and reactivity of uranium are topics of sustained interest because of their importance to the development of nuclear fuel processing methods, and a more complete understanding of the factors that govern the mobility and fate of the element in the environment. Tandem mass spectrometry can be used to examine the intrinsic reactivity (i.e., free from influence of solvent and other condensed phase effects) of a wide range of metal ion complexes in a species-specific fashion. Here, electrospray ionization, collision-induced dissociation, and gas-phase ion-molecule reactions were used to create and characterize ions derived from precursors composed of uranyl cation (UVIO2 2+) coordinated by formate or acetate ligands. Anionic complexes containing UVIO2 2+ and formate ligands fragment by decarboxylation and elimination of CH2=O, ultimately to produce an oxo-hydride species [UVIO2(O)(H)]-. Cationic species ultimately dissociate to make [UVIO2(OH)]+. Anionic complexes containing acetate ligands exhibit an initial loss of acetyloxyl radical, CH3CO2•, with associated reduction of uranyl to UVO2 +. Subsequent CID steps cause elimination of CO2 and CH4, ultimately to produce [UVO2(O)]-. Loss of CH4 occurs by an intra-complex H+ transfer process that leaves UVO2 + coordinated by acetate and acetate enolate ligands. A subsequent dissociation step causes elimination of CH2=C=O to leave [UVO2(O)]-. Elimination of CH4 is also observed as a result of hydrolysis caused by ion-molecule reaction with H2O. The reactions of other anionic species with gas-phase H2O create hydroxyl products, presumably through the elimination of H2.

  18. Thermodynamics of Uranyl Minerals: Enthalpies of Formation of Uranyl Oxide Hydrates

    Energy Technology Data Exchange (ETDEWEB)

    K. Kubatko; K. Helean; A. Navrotsky; P.C. Burns

    2005-05-11

    The enthalpies of formation of seven uranyl oxide hydrate phases and one uranate have been determined using high-temperature oxide melt solution calorimetry: [(UO{sub 2}){sub 4}O(OH){sub 6}](H{sub 2}O){sub 5}, metaschoepite; {beta}-UO{sub 2}(OH){sub 2}; CaUO{sub 4}; Ca(UO{sub 2}){sub 6}O{sub 4}(OH){sub 6}(H{sub 2}O){sub 8}, becquerelite; Ca(UO{sub 2}){sub 4}O{sub 3}(OH){sub 4}(H{sub 2}O){sub 2}; Na(UO{sub 2})O(OH), clarkeite; Na{sub 2}(UO{sub 2}){sub 6}O{sub 4}(OH){sub 6}(H{sub 2}O){sub 7}, the sodium analogue of compreignacite and Pb{sub 3}(UO{sub 2}){sub 8}O{sub 8}(OH){sub 6}(H{sub 2}O){sub 2}, curite. The enthalpy of formation from the binary oxides, {Delta}H{sub f-ox}, at 298 K was calculated for each compound from the respective drop solution enthalpy, {Delta}H{sub ds}. The standard enthalpies of formation from the elements, {Delta}H{sub f}{sup o}, at 298 K are -1791.0 {+-} 3.2, -1536.2 {+-} 2.8, -2002.0 {+-} 3.2, -11389.2 {+-} 13.5, -6653.1 {+-} 13.8, -1724.7 {+-} 5.1, -10936.4 {+-} 14.5 and -13163.2 {+-} 34.4 kJ mol{sup -1}, respectively. These values are useful in exploring the stability of uranyl oxide hydrates in auxiliary chemical systems, such as those expected in U-contaminated environments.

  19. Colorimetric peroxidase mimetic assay for uranyl detection in sea water

    KAUST Repository

    Zhang, Dingyuan

    2015-03-04

    Uranyl (UO2 2+) is a form of uranium in aqueous solution that represents the greatest risk to human health because of its bioavailability. Different sensing techniques have been used with very sensitive detection limits especially the recently reported uranyl-specific DNAzymes systems. However, to the best of our knowledge, few efficient detection methods have been reported for uranyl sensing in seawater. Herein, gold nanoclusters (AuNCs) are employed in an efficient spectroscopic method to detect uranyl ion (UO2 2+) with a detection limit of 1.86 ÎM. In the absence of UO2 2+, the BSA-stabilized AuNCs (BSA-AuNCs) showed an intrinsic peroxidase-like activity. In the presence of UO2 2+, this activity can be efficiently restrained. The preliminary quenching mechanism and selectivity of UO2 2+ was also investigated and compared with other ions. This design strategy could be useful in understanding the binding affinity of protein-stabilized AuNCs to UO2 2+ and consequently prompt the recycling of UO2 2+ from seawater.

  20. Durable phosphate-selective electrodes based on uranyl salophenes

    NARCIS (Netherlands)

    Wroblewski, Wojciech; Wojciechowski, Kamil; Dybko, Artur; Brzozka, Zbigniew; Egberink, Richard J.M.; Snellink-Ruel, Bianca H.M.; Reinhoudt, David N.

    2001-01-01

    Lipophilic uranyl salophenes derivatives were used as ionophores in durable phosphate-selective electrodes. The influence of the ionophore structure and membrane composition (polarity of plasticizer, the amount of incorporated ionic sites) on the electrode selectivity and long-term stability were st

  1. Uranyl salophenes as ionophores for phosphate-selective electrodes

    NARCIS (Netherlands)

    Wroblewski, Wojciech; Wojciechowski, Kamil; Dybko, Artur; Brzozka, Zbigniew; Egberink, Richard J.M.; Snellink-Ruel, Bianca H.M.; Reinhoudt, David N.

    2000-01-01

    Anion selectivities of poly(vinylchloride) (PVC) plasticized membranes containing uranyl salophene derivatives were presented. The influence of the membrane components (i.e. ionophore structure, dielectric constant and structure of plasticizer, the amount of incorporated ammonium salt) on its phosph

  2. Multi-scale modelling of uranyl chloride solutions

    Energy Technology Data Exchange (ETDEWEB)

    Nguyen, Thanh-Nghi; Duvail, Magali, E-mail: magali.duvail@icsm.fr; Villard, Arnaud; Dufrêche, Jean-François, E-mail: jean-francois.dufreche@univ-montp2.fr [Institut de Chimie Séparative de Marcoule (ICSM), UMR 5257, CEA-CNRS-Université Montpellier 2-ENSCM, Site de Marcoule, Bâtiment 426, BP 17171, F-30207 Bagnols-sur-Cèze Cedex (France); Molina, John Jairo [Fukui Institute for Fundamental Chemistry, Kyoto University, Takano-Nishihiraki-cho 34-4, Sakyo-ku, Kyoto 606-8103 (Japan); Guilbaud, Philippe [CEA/DEN/DRCP/SMCS/LILA, Marcoule, F-30207 Bagnols-sur-Cèze Cedex (France)

    2015-01-14

    Classical molecular dynamics simulations with explicit polarization have been successfully used to determine the structural and thermodynamic properties of binary aqueous solutions of uranyl chloride (UO{sub 2}Cl{sub 2}). Concentrated aqueous solutions of uranyl chloride have been studied to determine the hydration properties and the ion-ion interactions. The bond distances and the coordination number of the hydrated uranyl are in good agreement with available experimental data. Two stable positions of chloride in the second hydration shell of uranyl have been identified. The UO{sub 2}{sup 2+}-Cl{sup −} association constants have also been calculated using a multi-scale approach. First, the ion-ion potential averaged over the solvent configurations at infinite dilution (McMillan-Mayer potential) was calculated to establish the dissociation/association processes of UO{sub 2}{sup 2+}-Cl{sup −} ion pairs in aqueous solution. Then, the association constant was calculated from this potential. The value we obtained for the association constant is in good agreement with the experimental result (K{sub UO{sub 2Cl{sup +}}} = 1.48 l mol{sup −1}), but the resulting activity coefficient appears to be too low at molar concentration.

  3. Polaron effects in the protonic conductor hydrogen uranyl phosphate

    Energy Technology Data Exchange (ETDEWEB)

    Lupu, D. (Inst. of Isotopic and Molecular Technology, Cluj-Napoca (Romania)); Grecu, R. (Inst. of Chemistry, Cluj-Napoca (Romania)); Biris, A.R. (Inst. of Isotopic and Molecular Technology, Cluj-Napoca (Romania))

    1993-08-01

    The isotope effects on the conductivity of hydrogen uranyl phosphate reveal ionic polaron effects in this solid protonic conductor, in agreement with the small polaron theory. An absorption band is observed at 0.67 eV, which can be correlated with the conduction mechanism consisting in both tunnelling and over-barrier hopping processes. (orig.)

  4. Residual biomass for removal of uranyl ions;Biomassa residual para remocao de ions uranilo

    Energy Technology Data Exchange (ETDEWEB)

    Boniolo, Milena Rodrigues [Universidade Federal de Sao Carlos (UFScar), SP (Brazil). Dept. de Biogeoquimica Ambiental; Yamaura, Mitiko; Monteiro, Raquel Almeida, E-mail: milenaboniolo@usp.b [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil). Centro de Quimica e Meio Ambiente

    2010-07-01

    Activities related to nuclear industry, production of phosphoric acid and hospitals have generated considerable volumes of radioactive waste containing uranyl ions. Banana pith was characterized by scanning electron microscopy and Fourier transform infrared spectroscopy and was investigated as a biosorbent for uranyl ions from nitric solutions by batch experiments. Influences of adsorbent size, kinetics and equilibrium adsorption were studied. The biosorption of the uranyl ions followed pseudo-second-order kinetics. The adsorption isotherm data were closely fitted to the Freundlich equation. (author)

  5. Adsorption of uranyl ion on acid-modified zeolitic mineral clinoptilolite

    Directory of Open Access Journals (Sweden)

    Matijašević Srđan D.

    2009-01-01

    Full Text Available In this paper, the results of adsorption of uranyl ion on acid-modified zeolitic mineral clinoptilolite are presented. Adsorption was investigated at different amounts of solid phase in suspension, as well as at different pH values. The modified clinoptilolite samples were obtained by treatment of clinoptilolite with acids: hydrochloric, oxalyc and citric. Starting and modified clinoptilolites were characterized by chemical analysis, thermal (DT/TG analysis and by determination of cation exchange capacity, while starting and nonadsorbed amounts of uranyl ion were determined by fluorometric method. Uranyl ion adsorption experiments on natural unmodified zeolitic mineral showed that uranyl ion adsorption was low (29.2% and that treatment of clinoptilolite with acids significantly increases the adsorption of uranyl ion (>90%. In the case of acid treated clinoptilolites, the highest adsorption of uranyl ion was achieved on clinoptilolite modified with hydrochloric acid. Kinetics of adsorption showed that adsorption of uranyl ion begins very fast and that the most of uranyl ion was adsorbed in first 30 min. Practically, there were no changes in uranyl ion adsorption within next 72 h.

  6. The scientific basis for chelation: animal studies and lead chelation.

    Science.gov (United States)

    Smith, Donald; Strupp, Barbara J

    2013-12-01

    This presentation summarizes several of the rodent and non-human studies that we have conducted to help inform the efficacy and clinical utility of succimer (meso-2,3-dimercaptosuccincinic acid) chelation treatment. We address the following questions: (1) What is the extent of body lead, and in particular brain lead reduction with chelation, and do reductions in blood lead accurately reflect reductions in brain lead? (2) Can succimer treatment alleviate the neurobehavioral impacts of lead poisoning? And (3) does succimer treatment, in the absence of lead poisoning, produce neurobehavioral deficits? Results from our studies in juvenile primates show that succimer treatment is effective at accelerating the elimination of lead from the body, but chelation was only marginally better than the complete cessation of lead exposure alone. Studies in lead-exposed adult primates treated with a single 19-day course of succimer showed that chelation did not measurably reduce brain lead levels compared to vehicle-treated controls. A follow-up study in rodents that underwent one or two 21-day courses of succimer treatment showed that chelation significantly reduced brain lead levels, and that two courses of succimer were significantly more efficacious at reducing brain lead levels than one. In both the primate and rodent studies, reductions in blood lead levels were a relatively poor predictor of reductions in brain lead levels. Our studies in rodents demonstrated that it is possible for succimer chelation therapy to alleviate certain types of lead-induced behavioral/cognitive dysfunction, suggesting that if a succimer treatment protocol that produced a substantial reduction of brain lead levels could be identified for humans, a functional benefit might be derived. Finally, we also found that succimer treatment produced lasting adverse neurobehavioral effects when administered to non-lead-exposed rodents, highlighting the potential risks of administering succimer or other metal-chelating

  7. Electrochemical uranyl cation biosensor with DNA oligonucleotides as receptor layer.

    Science.gov (United States)

    Jarczewska, Marta; Ziółkowski, Robert; Górski, Łukasz; Malinowska, Elżbieta

    2014-04-01

    The present study aims at the further development of the uranyl oligonucleotide-based voltammetric biosensor, which takes advantage of strong interaction between UO2(2+) and phosphate DNA backbone. Herein we report the optimization of working parameters of previously elaborated electrochemical DNA biosensor. It is shown that the sensor sensitivity is highly dependent on the oligonucleotide probe length and the incubation time of sensor in a sample solution. Consequently, the highest sensitivity was obtained for 10-nucleotide sequence and 60 min incubation time. The lower detection limit towards uranyl cation for developed biosensor was 30 nM. The influence of mixed monolayers and the possibility of developing a non-calibration device were also investigated. The selectivity of the proposed biosensor was significantly improved via elimination of adenine nucleobases from the DNA probe. Moreover, the regeneration procedure was elaborated and tested to prolong the use of the same biosensor for 4 subsequent determinations of UO2(2+).

  8. Overview of current chelation practices

    Directory of Open Access Journals (Sweden)

    Y. Aydinok

    2011-12-01

    Full Text Available Deferoxamine (DFO is reference standard therapy for transfusional iron overload since the 1980s. Although it is a highly effective iron chelator, the compliance problem to subcutaneous administration of DFO remains as the major problem. The oral chelator Deferiprone (DFP has no marketing licence in North America, however, it has been licensed in India since 1994 and the European Union (EU granted marketing approval for DFP in 1999, specifically for patients with thalassemia major when DFO is inadequate, intolerable or unacceptable. There are still limited data available on the use of DFP in children between 6 and 10 years of age, and no data on DFP use in children under 6 years of age. Subsequently the oral chelator Deferasirox (DFX was approved by FDA and EMA for the treatment of patients with transfusional iron overload -older than 2 years of age- as first line therapy, in 2005 and 2006 respectively. The primary objective of iron chelation is to maintain body iron at safe levels at all times but once iron is accumulated, the objective of iron chelation is to reduce tissue iron to safe levels which is a slow process. The chelation regimen, dose and frequency of administration, of the chelator(s are mainly determined based on body iron burden, presence of myocardial iron and the transfusional iron loading rate. A proper monitoring of chelation is of importance for measuring the response rate to a particular regimen and providing dose adjustments to enhance chelation efficacy and to avoid toxicity. Efficacy of a chelation regimen may exhibit individual variability resulting from factors such as absorbtion and metabolism of the chelator. Tolerability and compliance are also individual variables effecting the response to chelation. Understanding of advantages and limitations of chelators, accurately determining chelation needs of patients with iron overload and designing individualized chelation regimens with less toxicity but optimum efficacy

  9. Structure and bonding in crystalline cesium uranyl tetrachloride under pressure.

    Science.gov (United States)

    Osman, Hussien H; Pertierra, Pilar; Salvadó, Miguel A; Izquierdo-Ruiz, F; Recio, J M

    2016-07-21

    A thorough investigation of pressure effects on the structural properties of crystalline cesium uranyl chloride was performed by means of first-principles calculations within the density functional theory framework. Total energies, equilibrium geometries and vibrational frequencies were computed at selected pressures up to 50 GPa. Zero pressure results present good agreement with available experimental and theoretical data. Our calculated equation of state parameters reveal that Cs2UO2Cl4 is a high compressible material, similar to other ionic compounds with cesium cations, and displays a structural anisotropic behavior guided by the uranyl moiety. An unexpected variation of the U-O bond length, dUO, is detected as pressure is applied. It leads to a dUO-stretching frequency relationship that cannot be described by the traditional Badger's rule. Interestingly enough, it can be explained in terms of a change in the main factor controlling dUO. At low pressure, the charge transferred to the uranyl cation induces an increase of the bond length and a red shift of the stretching frequencies, whereas it is the mechanical effect of the applied pressure above 10 GPa that is the dominant factor that leads to a shortening of dUO and a blue shift of the stretching frequencies.

  10. Uranyl-glycine-water complexes in solution: comprehensive computational modeling of coordination geometries, stabilization energies, and luminescence properties.

    Science.gov (United States)

    Su, Jing; Zhang, Kai; Schwarz, W H Eugen; Li, Jun

    2011-03-21

    Comprehensive computational modeling of coordination structures, thermodynamic stabilities, and luminescence spectra of uranyl-glycine-water complexes [UO(2)(Gly)(n)aq(m)](2+) (Gly = glycine, aq = H(2)O, n = 0-2, m = 0-5) in aqueous solution has been carried out using relativistic density functional approaches. The solvent is approximated by a dielectric continuum model and additional explicit water molecules. Detailed pictures are obtained by synergic combination of experimental and theoretical data. The optimal equatorial coordination numbers of uranyl are determined to be five. The energies of several complex conformations are competitively close to each other. In non-basic solution the most probable complex forms are those with two water ligands replaced by the bidentate carboxyl groups of zwitterionic glycine. The N,O-chelation in non-basic solution is neither entropically nor enthalpically favored. The symmetric and antisymmetric stretch vibrations of the nearly linear O-U-O unit determine the luminescence features. The shapes of the vibrationally resolved experimental solution spectra are reproduced theoretically with an empirically fitted overall line-width parameter. The calculated luminescence origins correspond to thermally populated, near-degenerate groups of the lowest electronically excited states of (3)Δ(g) and (3)Φ(g) character, originating from (U-O)σ(u) → (U-5f)δ(u),ϕ(u) configurations of the linear [OUO](2+) unit. The intensity distributions of the vibrational progressions are consistent with U-O bond-length changes around 5 1/2 pm. The unusually high intensity of the short wavelength foot is explained by near-degeneracy of vibrationally and electronically excited states, and by intensity enhancement through the asymmetric O-U-O stretch mode. The combination of contemporary computational chemistry and experimental techniques leads to a detailed understanding of structures, thermodynamics, and luminescence of actinide compounds, including

  11. Iron Chelation and Multiple Sclerosis

    Directory of Open Access Journals (Sweden)

    Kelsey J. Weigel

    2014-01-01

    Full Text Available Histochemical and MRI studies have demonstrated that MS (multiple sclerosis patients have abnormal deposition of iron in both gray and white matter structures. Data is emerging indicating that this iron could partake in pathogenesis by various mechanisms, e.g., promoting the production of reactive oxygen species and enhancing the production of proinflammatory cytokines. Iron chelation therapy could be a viable strategy to block iron-related pathological events or it can confer cellular protection by stabilizing hypoxia inducible factor 1α, a transcription factor that normally responds to hypoxic conditions. Iron chelation has been shown to protect against disease progression and/or limit iron accumulation in some neurological disorders or their experimental models. Data from studies that administered a chelator to animals with experimental autoimmune encephalomyelitis, a model of MS, support the rationale for examining this treatment approach in MS. Preliminary clinical studies have been performed in MS patients using deferoxamine. Although some side effects were observed, the large majority of patients were able to tolerate the arduous administration regimen, i.e., 6–8 h of subcutaneous infusion, and all side effects resolved upon discontinuation of treatment. Importantly, these preliminary studies did not identify a disqualifying event for this experimental approach. More recently developed chelators, deferasirox and deferiprone, are more desirable for possible use in MS given their oral administration, and importantly, deferiprone can cross the blood–brain barrier. However, experiences from other conditions indicate that the potential for adverse events during chelation therapy necessitates close patient monitoring and a carefully considered administration regimen.

  12. Evaluation of a new DTPA-derivative chelator: comparative biodistribution and imaging studies of [sup 111]In-labeled B3 monoclonal antibody in athymic mice bearing human epidermoid carcinoma xenografts. [Diethylenetriaminpentaacetic acid

    Energy Technology Data Exchange (ETDEWEB)

    Camera, L.; Kinuya, S.; Garmestani, K.; Pai, L.H.; Brechbiel, M.W.; Gansow, O.A.; Paik, C.H.; Pastan, I.; Carrasquillo, J.A. (National Cancer Inst., Bethesda, MD (United States))

    1993-11-01

    Biodistribution and imaging characteristics of monoclonal antibody (MAb) B3 conjugated to either the 2-(p-isothiocvanatobenzyl)-cyclohexyl-DTPA (CHX-B) or 2-(p-isothiocyanatobenzyl)-6-methyl-DTPA (1B4M) and labeled with [sup 111]In, were evalulated in nude mice bearing A431 human epidermoid carcinoma xenografts. MAb B3, is a murine IgG1k reacting with a carbohydrate antigen abundantly expressed by most carcinomas. Both [sup 111]In-(CHX-B)-B3 and [sup 111]In-(1B4M)-B3 showed good tumor targeting with peak values observed at 72 h with 27.6 [+-] 7.6 and 25.4 [+-] 1.7% ID/g, respectively (P > 0.05). High tumor-to-organ ratios were also observed and, confirmed by the imaging results. In particular, tumor-to liver ratios increased from 5.0 [+-] 0.9 at 24 h to 9.2 [+-] 2.0 at 168 h for [sup 111]In-(CHX-B)-B3 and from 4.5 [+-] 0.6 to 8.9 [+-] 3.5 for [sup 111]In-(1B4M)-B3. This was mainly the result of low liver accumulation of both [sup 111]In-(CHX-B)-B3 and [sup 111]In-(1B4M)-B3, with only 2.48 [+-] 0.46 and 2.5 [+-] 0.9% ID/g at 168h, respectively (P > 0.05). Our findings indicate that either CHX-B or 1B4M can be successfully used for [sup 111]In-labeling of MAbs and that [sup 111]In-B3 may represent a promising radioimmunoimaging agent. (Author).

  13. Quantification of uranyl in presence of citric acid; Cuantificacion de uranilo en presencia de acido citrico

    Energy Technology Data Exchange (ETDEWEB)

    Garcia G, N.; Barrera D, C.E. [UAEM, Facultad de Quimica, 50000 Toluca, Estado de Mexico (Mexico); Ordonez R, E. [ININ, 52750 La Marquesa, Estado de Mexico (Mexico)]. e-mail: nidgg@yahoo.com.mx

    2007-07-01

    To determine the influence that has the organic matter of the soil on the uranyl sorption on some solids is necessary to have a detection technique and quantification of uranyl that it is reliable and sufficiently quick in the obtaining of results. For that in this work, it intends to carry out the uranyl quantification in presence of citric acid modifying the Fluorescence induced by UV-Vis radiation technique. Since the uranyl ion is very sensitive to the medium that contains it, (speciation, pH, ionic forces, etc.) it was necessary to develop an analysis technique that stands out the fluorescence of uranyl ion avoiding the out one that produce the organic acids. (Author)

  14. Luminescent lanthanide chelates and methods of use

    Science.gov (United States)

    Selvin, Paul R.; Hearst, John

    1997-01-01

    The invention provides lanthanide chelates capable of intense luminescence. The celates comprise a lanthanide chelator covalently joined to a coumarin-like or quinolone-like sensitizer. Exemplary sensitzers include 2- or 4-quinolones, 2- or 4-coumarins, or derivatives thereof e.g. carbostyril 124 (7-amino-4-methyl-2-quinolone), coumarin 120 (7-amino-4-methyl-2-coumarin), coumarin 124 (7-amino-4-(trifluoromethyl)-2-coumarin), aminomethyltrimethylpsoralen, etc. The chelates form high affinity complexes with lanthanides, such as terbium or europium, through chelator groups, such as DTPA. The chelates may be coupled to a wide variety of compounds to create specific labels, probes, diagnostic and/or therapeutic reagents, etc. The chelates find particular use in resonance energy transfer between chelate-lanthanide complexes and another luminescent agent, often a fluorescent non-metal based resonance energy acceptor. The methods provide useful information about the structure, conformation, relative location and/or interactions of macromolecules.

  15. Chelators for investigating zinc metalloneurochemistry.

    Science.gov (United States)

    Radford, Robert J; Lippard, Stephen J

    2013-04-01

    The physiology and pathology of mobile zinc signaling has become an important topic in metalloneurochemistry. To study the action of mobile zinc effectively, specialized tools are required that probe the temporal and positional changes of zinc ions within live tissue and cells. In the present article we describe the design and implementation of selective zinc chelators as antagonists to interrogate the function of mobile zinc, with an emphasis on the pools of vesicular zinc in the terminals of hippocampal mossy fiber buttons.

  16. Combination therapies in iron chelation

    Directory of Open Access Journals (Sweden)

    Raffaella Origa

    2014-12-01

    Full Text Available The availability of oral iron chelators and new non-invasive methods for early detection and treatment of iron overload, have significantly improved the life expectancy and quality of life of patients with b thalassemia major. However, monotherapy is not effective in all patients for a variety of reasons. We analyzed the most relevant reports recently published on alternating or combined chelation therapies in thalassemia major with special attention to safety aspects and to their effects in terms of reduction of iron overload in different organs, improvement of complications, and survival. When adverse effects, such as gastrointestinal upset with deferasirox or infusional site reactions with deferoxamine are not tolerable and organ iron is in an acceptable range, alternating use of two chelators (drugs taken sequentially on different days, but not taken on the same day together may be a winning choice. The association deferiprone and deferoxamine should be the first choice in case of heart failure and when dangerously high levels of cardiac iron exist. Further research regarding the safety and efficacy of the most appealing combination treatment, deferiprone and deferasirox, is needed before recommendations for routine clinical practice can be made.

  17. Monofunctionalization of Calix[4]arene Tetracarboxylic Acid at the Upper Rim with Isothiocyanate Group: First Bifunctional Chelating Agent for Alpha-Emitter Ac-225.

    Science.gov (United States)

    Chen, Xiaoyuan; Ji, Min; Fisher, Darrell R; Wai, Chien M

    1999-09-01

    A procedure is reported for synthesizing a novel, water-soluble bifunctional chelating agent derived from calix[4]arene. This chelate features tetracarboxylic acid groups at the lower rim as an actinium-225 ionophore, and an isothiocyanate functional group at the upper rim for labeling of the N-terminus of monoclonal antibodies through thiourea linkage.

  18. Enhanced Adsorption and Recovery of Uranyl Ions by NikR Mutant-Displaying Yeast

    Directory of Open Access Journals (Sweden)

    Kouichi Kuroda

    2014-04-01

    Full Text Available Uranium is one of the most important metal resources, and the technology for the recovery of uranyl ions (UO22+ from aqueous solutions is required to ensure a semi-permanent supply of uranium. The NikR protein is a Ni2+-dependent transcriptional repressor of the nickel-ion uptake system in Escherichia coli, but its mutant protein (NikRm is able to selectively bind uranyl ions in the interface of the two monomers. In this study, NikRm protein with ability to adsorb uranyl ions was displayed on the cell surface of Saccharomyces cerevisiae. To perform the binding of metal ions in the interface of the two monomers, two metal-binding domains (MBDs of NikRm were tandemly fused via linker peptides and displayed on the yeast cell surface by fusion with the cell wall-anchoring domain of yeast α-agglutinin. The NikRm-MBD-displaying yeast cells with particular linker lengths showed the enhanced adsorption of uranyl ions in comparison to the control strain. By treating cells with citrate buffer (pH 4.3, the uranyl ions adsorbed on the cell surface were recovered. Our results indicate that the adsorption system by yeast cells displaying tandemly fused MBDs of NikRm is effective for simple and concentrated recovery of uranyl ions, as well as adsorption of uranyl ions.

  19. Enhanced adsorption and recovery of uranyl ions by NikR mutant-displaying yeast.

    Science.gov (United States)

    Kuroda, Kouichi; Ebisutani, Kazuki; Iida, Katsuya; Nishitani, Takashi; Ueda, Mitsuyoshi

    2014-04-11

    Uranium is one of the most important metal resources, and the technology for the recovery of uranyl ions (UO22+) from aqueous solutions is required to ensure a semi-permanent supply of uranium. The NikR protein is a Ni2+-dependent transcriptional repressor of the nickel-ion uptake system in Escherichia coli, but its mutant protein (NikRm) is able to selectively bind uranyl ions in the interface of the two monomers. In this study, NikRm protein with ability to adsorb uranyl ions was displayed on the cell surface of Saccharomyces cerevisiae. To perform the binding of metal ions in the interface of the two monomers, two metal-binding domains (MBDs) of NikRm were tandemly fused via linker peptides and displayed on the yeast cell surface by fusion with the cell wall-anchoring domain of yeast α-agglutinin. The NikRm-MBD-displaying yeast cells with particular linker lengths showed the enhanced adsorption of uranyl ions in comparison to the control strain. By treating cells with citrate buffer (pH 4.3), the uranyl ions adsorbed on the cell surface were recovered. Our results indicate that the adsorption system by yeast cells displaying tandemly fused MBDs of NikRm is effective for simple and concentrated recovery of uranyl ions, as well as adsorption of uranyl ions.

  20. Understanding the bonding nature of uranyl ion and functionalized graphene: a theoretical study.

    Science.gov (United States)

    Wu, Qun-Yan; Lan, Jian-Hui; Wang, Cong-Zhi; Xiao, Cheng-Liang; Zhao, Yu-Liang; Wei, Yue-Zhou; Chai, Zhi-Fang; Shi, Wei-Qun

    2014-03-20

    Studying the bonding nature of uranyl ion and graphene oxide (GO) is very important for understanding the mechanism of the removal of uranium from radioactive wastewater with GO-based materials. We have optimized 22 complexes between uranyl ion and GO applying density functional theory (DFT) combined with quasi-relativistic small-core pseudopotentials. The studied oxygen-containing functional groups include hydroxyl, carboxyl, amido, and dimethylformamide. It is observed that the distances between uranium atoms and oxygen atoms of GO (U-OG) are shorter in the anionic GO complexes (uranyl/GO(-/2-)) compared to the neutral GO ones (uranyl/GO). The formation of hydrogen bonds in the uranyl/GO(-/2-) complexes can enhance the binding ability of anionic GO toward uranyl ions. Furthermore, the thermodynamic calculations show that the changes of the Gibbs free energies in solution are relatively more negative for complexation reactions concerning the hydroxyl and carboxyl functionalized anionic GO complexes. Therefore, both the geometries and thermodynamic energies indicate that the binding abilities of uranyl ions toward GO modified by hydroxyl and carboxyl groups are much stronger compared to those by amido and dimethylformamide groups. This study can provide insights for designing new nanomaterials that can efficiently remove radionuclides from radioactive wastewater.

  1. Escherichia coli response to uranyl exposure at low pH and associated protein regulations.

    Directory of Open Access Journals (Sweden)

    Arbia Khemiri

    Full Text Available Better understanding of uranyl toxicity in bacteria is necessary to optimize strains for bioremediation purposes or for using bacteria as biodetectors for bioavailable uranyl. In this study, after different steps of optimization, Escherichia coli cells were exposed to uranyl at low pH to minimize uranyl precipitation and to increase its bioavailability. Bacteria were adapted to mid acidic pH before exposure to 50 or 80 µM uranyl acetate for two hours at pH≈3. To evaluate the impact of uranium, growth in these conditions were compared and the same rates of cells survival were observed in control and uranyl exposed cultures. Additionally, this impact was analyzed by two-dimensional differential gel electrophoresis proteomics to discover protein actors specifically present or accumulated in contact with uranium.Exposure to uranium resulted in differential accumulation of proteins associated with oxidative stress and in the accumulation of the NADH/quinone oxidoreductase WrbA. This FMN dependent protein performs obligate two-electron reduction of quinones, and may be involved in cells response to oxidative stress. Interestingly, this WrbA protein presents similarities with the chromate reductase from E. coli, which was shown to reduce uranyl in vitro.

  2. Synthesis, X-ray crystallography, thermal studies, spectroscopic and electrochemistry investigations of uranyl Schiff base complexes.

    Science.gov (United States)

    Asadi, Zahra; Shorkaei, Mohammad Ranjkesh

    2013-03-15

    Some tetradentate salen type Schiff bases and their uranyl complexes were synthesized and characterized by UV-Vis, NMR, IR, TG, C.H.N. and X-ray crystallographic studies. From these investigations it is confirmed that a solvent molecule occupied the fifth position of the equatorial plane of the distorted pentagonal bipyramidal structure. Also, the kinetics of complex decomposition by using thermo gravimetric methods (TG) was studied. The thermal decomposition reactions are first order for the studied complexes. To examine the properties of uranyl complexes according to the substitutional groups, we have carried out the electrochemical studies. The electrochemical reactions of uranyl Schiff base complexes in acetonitrile were reversible.

  3. Beliefs about chelation among thalassemia patients

    Directory of Open Access Journals (Sweden)

    Trachtenberg Felicia L

    2012-12-01

    Full Text Available Abstract Background Understanding patients’ views about medication is crucial to maximize adherence. Thalassemia is a congenital blood disorder requiring chronic blood transfusions and daily iron chelation therapy. Methods The Beliefs in Medicine Questionnaire (BMQ was used to assess beliefs in chelation in thalassemia patients from North America and London in the Thalassemia Longitudinal Cohort (TLC of the Thalassemia Clinical Research Network (TCRN. Chelation adherence was based on patient report of doses administered out of those prescribed in the last four weeks. Results Of 371 patients (ages 5-58y, mean 24y, 93% were transfused and 92% receiving chelation (26% deferoxamine (DFO; a slow subcutaneous infusion via portable pump, 63% oral, 11% combination. Patients expressed high “necessity” for transfusion (96%, DFO chelation (92% and oral chelation (89%, with lower “concern” about treatment (48%, 39%, 19% respectively. Concern about oral chelation was significantly lower than that of DFO (p Conclusions Despite their requirement for multimodal therapy, thalassemia patients have positive views about medicine, more so than in other disease populations. Patients may benefit from education about the tolerability of chelation and strategies to effectively cope with side effects, both of which might be beneficial in lowering body iron burden. Clinicaltrials.gov identifier NCT00661804

  4. Adsorption of uranyl species on hydroxylated titanium carbide nanosheet: A first-principles study.

    Science.gov (United States)

    Zhang, Yu-Juan; Lan, Jian-Hui; Wang, Lin; Wu, Qun-Yan; Wang, Cong-Zhi; Bo, Tao; Chai, Zhi-Fang; Shi, Wei-Qun

    2016-05-05

    In this work, hydroxylated titanium carbide Ti3C2(OH)2, a representative of the two-dimensional transition metal carbides, has been predicted to be an effective adsorbent for uranyl ions in aqueous environments for the first time using density functional theory simulations. The calculations revealed that the uranyl ion can strongly bind with Ti3C2(OH)2 nanosheet in aqueous solution regardless of the presence of anionic ligands such as OH(-), Cl(-) and NO3(-). The bidentate coordination of uranyl to the surface is energetically more favorable than other adsorption configurations, and the uranyl ion prefers to bind with the deprotonated O adsorption site rather than the protonated one on the hydroxylated surface. During the adsorption process, the chemical adsorption as well as the formation of hydrogen bonds is the dominant factor.

  5. Importance of iron chelation therapy

    Directory of Open Access Journals (Sweden)

    A. Varoğlu

    2011-12-01

    Full Text Available It is necessary to remember that today patients have different options of chelation treatment, as desferrioxamine, deferiprone and deferasirox are available. However, a patient has to be compliant with treatments. They have always to remember that too much iron causes different complications and could be a barrier for a definitive cure from thalassemia. 由于出现了去铁胺、去铁酮和去铁斯若等药物,病人现在可以选择不同的螯合治疗方式。 然而,病人必须适应这几种治疗方式。 他们必须时刻记住太多的铁元素会引发多种并发症,并对地中海贫血的彻底治疗造成阻碍。

  6. Metal ions, Alzheimer's disease and chelation therapy.

    Science.gov (United States)

    Budimir, Ana

    2011-03-01

    In the last few years, various studies have been providing evidence that metal ions are critically involved in the pathogenesis of major neurological diseases (Alzheimer, Parkinson). Metal ion chelators have been suggested as potential therapies for diseases involving metal ion imbalance. Neurodegeneration is an excellent target for exploiting the metal chelator approach to therapeutics. In contrast to the direct chelation approach in metal ion overload disorders, in neurodegeneration the goal seems to be a better and subtle modulation of metal ion homeostasis, aimed at restoring ionic balance. Thus, moderate chelators able to coordinate deleterious metals without disturbing metal homeostasis are needed. To date, several chelating agents have been investigated for their potential to treat neurodegeneration, and a series of 8-hydroxyquinoline analogues showed the greatest potential for the treatment of neurodegenerative diseases.

  7. Hydrothermal syntheses and characterization of uranyl tungstates with electro-neutral structural units

    Energy Technology Data Exchange (ETDEWEB)

    Balboni, Enrica; Burns, Peter C. [Univ. of Notre Dame, IN (United States). Dept. of Civil and Enviromental Engineering and Earth Sciences; Univ. of Notre Dame, IN (United States). Dept. of Chemistry and Biochemistry

    2015-11-01

    Two uranyl tungstates, (UO{sub 2})(W{sub 2}O{sub 7})(H{sub 2}O){sub 3} (1) and (UO{sub 2}){sub 3}(W{sub 2}O{sub 8})F{sub 2}(H{sub 2}O){sub 3} (2), were synthesized under hydrothermal conditions at 220 C and were structurally, chemically, and spectroscopically characterized. 1 Crystallizes in space group Pbcm, a = 6.673(5) Aa, b = 12.601(11) Aa, c = 11.552 Aa; 2 is in C2/m, a = 13.648(1) Aa, b = 16.852(1) Aa, c = 9.832(1) Aa, β = 125.980(1) {sup circle}. In 1 the U(VI) cations are present as (UO{sub 2}){sup 2+} uranyl ions that are coordinated by five oxygen atoms to give pentagonal bipyramids. These share two edges with two tungstate octahedra and single vertices with four additional octahedra, resulting in a sheet with the iriginite-type anion topology. Only water molecules are located in the interlayer. The structural units of 2 consist of (UO{sub 2}){sup 2+} uranyl oxy-fluoride pentagonal bipyramids present as either [UO{sub 2}F{sub 2}O{sub 3}]{sup -6} or [UO{sub 2}FO{sub 4}]{sup -5}, and strongly distorted tungstate octahedra. The linkage of uranyl pentagonal bipyramids and tungstate octahedra gives a unique sheet anion topology consisting of pentagons, squares and triangles. In 2, the uranyl tungstates sheets are connected into a novel electro-neutral three-dimensional framework through dimers of uranyl pentagonal bipyramids. These dimers connecting the sheets share an edge defined by F anions. 2 is the first example of a uranyl tungstate oxy-fluoride, and 1 and 2 are rare examples of uranyl compounds containing electro-neutral structural units.

  8. Control of oxo-group functionalization and reduction of the uranyl ion.

    Science.gov (United States)

    Arnold, Polly L; Pécharman, Anne-Frédérique; Lord, Rianne M; Jones, Guy M; Hollis, Emmalina; Nichol, Gary S; Maron, Laurent; Fang, Jian; Davin, Thomas; Love, Jason B

    2015-04-01

    Uranyl complexes of a large, compartmental N8-macrocycle adopt a rigid, "Pacman" geometry that stabilizes the U(V) oxidation state and promotes chemistry at a single uranyl oxo-group. We present here new and straightforward routes to singly reduced and oxo-silylated uranyl Pacman complexes and propose mechanisms that account for the product formation, and the byproduct distributions that are formed using alternative reagents. Uranyl(VI) Pacman complexes in which one oxo-group is functionalized by a single metal cation are activated toward single-electron reduction. As such, the addition of a second equivalent of a Lewis acidic metal complex such as MgN″2 (N″ = N(SiMe3)2) forms a uranyl(V) complex in which both oxo-groups are Mg functionalized as a result of Mg-N bond homolysis. In contrast, reactions with the less Lewis acidic complex [Zn(N″)Cl] favor the formation of weaker U-O-Zn dative interactions, leading to reductive silylation of the uranyl oxo-group in preference to metalation. Spectroscopic, crystallographic, and computational analysis of these reactions and of oxo-metalated products isolated by other routes have allowed us to propose mechanisms that account for pathways to metalation or silylation of the exo-oxo-group.

  9. Temperature and pH driven association in uranyl aqueous solutions

    Directory of Open Access Journals (Sweden)

    M. Druchok

    2012-12-01

    Full Text Available An association behavior of uranyl ions in aqueous solutions is explored. For this purpose a set of all-atom molecular dynamics simulations is performed. During the simulation, the fractions of uranyl ions involved in dimer and trimer formations were monitored. To accompany the fraction statistics one also collected distributions characterizing average times of the dimer and trimer associates. Two factors effecting the uranyl association were considered: temperature and pH. As one can expect, an increase of the temperature decreases an uranyl capability of forming the associates, thus lowering bound fractions/times and vice versa. The effect of pH was modeled by adding H+ or OH- ions to a "neutral" solution. The addition of hydroxide ions OH- favors the formation of the associates, thus increasing bound times and fractions. The extra H+ ions in a solution produce an opposite effect, thus lowering the uranyl association capability. We also made a structural analysis for all the observed associates to reveal the mutual orientation of the uranyl ions.

  10. Statistical evaluation of an improved quantitative immunofluorescence method of measuring serum antibody levels directed against intestinal bacteria

    NARCIS (Netherlands)

    Jansen, G.J.; Wilkinson, M.H.F.; Deddens, B.; Waaij, D. van der

    1993-01-01

    The accuracy of an improved quantitative immunofluorescence method to measure the antibody binding capacity of intestinal bacteria was assessed. The improvements comprise: calibration on a non-fading fluorescence standard (uranyl glass), prolonged camera exposure time (over 4 s) and shading correcti

  11. Characterization of the Aqueous Uranyl-Silicate Complex Using X-Ray Absorption Spectroscopy and Ab Initio Modeling

    Science.gov (United States)

    Vu, M.; Massey, M.; Huang, P.

    2015-12-01

    The speciation of aqueous uranium ions is an important factor in predicting its mobility and fate in the environment. Two major controls on speciation are pH and the presence of complexing ligands. For the case of aqueous uranyl, UO22+(aq), some common complexes include uranyl-hydroxy, uranyl-carbonato, and uranyl-calcium-carbonato complexes, all of which differ in chemical reactivity and mobility. Uranyl-silicate complexes are also known but remain poorly characterized. In this work, we studied uranyl speciation in a series of aqueous solutions of 0.1 mM uranyl and 2 mM silicate with pH ranging from 4 to 7. Extended X-Ray Absorption Fine Structure (EXAFS) spectra of these samples were recorded at the Stanford Synchrotron Radiation Lightsource (SLAC National Accelerator Laboratory). Of particular note are the uranyl and silicate concentrations employed in our experiments, which are lower than conditions in previously reported EXAFS studies and approach conditions in natural groundwater systems. Preliminary analyses of EXAFS data indicate that uranyl speciation changes across the pH range, consistent with published thermodynamic data that suggest uranyl-silicate complexes may be important for pH ~ 5 and below, while uranyl-carbonato complexes become dominant at circumneutral pH. To guide the interpretation of the EXAFS data, molecular-scale simulations were carried out using density functional theory. We considered two classes of models: (i) hydrated clusters, and (ii) ab initio molecular dynamics simulations of 3D-periodic models involving uranyl and silicate in water. These calculations reveal that at pH ~ 5, the uranyl speciation is the [UO2(H2O)4H3SiO4]+ complex formed by the substitution of an equatorial uranyl water with a monodentate silicate ligand. The evidence from experiments and simulations provide a consistent picture for the uranyl-silicate complex, which may be important in the transport of uranyl in acidic, silicate-rich waters.

  12. Questions and Answers on Unapproved Chelation Products

    Science.gov (United States)

    ... of the marketing scheme to convince consumers to purchase unapproved OTC chelation products. These test kits are ... feeds Follow FDA on Twitter Follow FDA on Facebook View FDA videos on YouTube View FDA photos ...

  13. SYNTHESIS AND APPLICATION OF IMINOCARBOXYLIC CHELATING FIBERS

    Institute of Scientific and Technical Information of China (English)

    LiHangqiu; ZhouShaoji

    1997-01-01

    In this paper,fibrous chelating exchangers with-N(CH2COOH)2 group have been prepared for the first time by a weakly basic anion exchange fiber (aminated fiber)as the starting materials.The fibers were quite effective for the adsorption of heavy metal ion such as Cu2+.In addition,IR spectrum of the structure of fibers confirms that it is feasible to prepare iminocarboxylic chelating fiber through direct carboxylation reaction.

  14. Temperature and pH driven association in uranyl aqueous solutions

    CERN Document Server

    Druchok, M; 10.5488/CMP.15.43602

    2013-01-01

    An association behavior of uranyl ions in aqueous solutions is explored. For this purpose a set of all-atom molecular dynamics simulations is performed. During the simulation, the fractions of uranyl ions involved in dimer and trimer formations were monitored. To accompany the fraction statistics one also collected distributions characterizing average times of the dimer and trimer associates. Two factors effecting the uranyl association were considered: temperature and pH. As one can expect, an increase of the temperature decreases an uranyl capability of forming the associates, thus lowering bound fractions/times and vice versa. The effect of pH was modeled by adding H^+ or OH^- ions to a "neutral" solution. The addition of hydroxide ions OH^- favors the formation of the associates, thus increasing bound times and fractions. The extra H^+ ions in a solution produce an opposite effect, thus lowering the uranyl association capability. We also made a structural analysis for all the observed associates to reveal...

  15. Atomistic simulations of calcium uranyl(VI) carbonate adsorption on calcite and stepped-calcite surfaces.

    Science.gov (United States)

    Doudou, Slimane; Vaughan, David J; Livens, Francis R; Burton, Neil A

    2012-07-17

    Adsorption of actinyl ions onto mineral surfaces is one of the main mechanisms that control the migration of these ions in environmental systems. Here, we present computational classical molecular dynamics (MD) simulations to investigate the behavior of U(VI) in contact with different calcite surfaces. The calcium-uranyl-carbonate [Ca(2)UO(2)(CO(3))(3)] species is shown to display both inner- and outer-sphere adsorption to the flat {101̅4} and the stepped {314̅8} and {31̅2̅16} planes of calcite. Free energy calculations, using the umbrella sampling method, are employed to simulate adsorption paths of the same uranyl species on the different calcite surfaces under aqueous condition. Outer-sphere adsorption is found to dominate over inner-sphere adsorption because of the high free energy barrier of removing a uranyl-carbonate interaction and replacing it with a new uranyl-surface interaction. An important binding mode is proposed involving a single vicinal water monolayer between the surface and the sorbed complex. From the free energy profiles of the different calcite surfaces, the uranyl complex was also found to adsorb preferentially on the acute-stepped {314̅8} face of calcite, in agreement with experiment.

  16. Status Update: Uranyl Nitrate Calibration Loop Equipment (UNCLE) at ORNL

    Energy Technology Data Exchange (ETDEWEB)

    Ladd-Lively, Jennifer L [ORNL

    2009-01-01

    The successful completion of a field trial of safeguards monitoring equipment at a natural uranium conversion plant (NUCP) demonstrated the need for a facility in which to perform full-scale equipment testing under controlled conditions prior to field deployment of safeguards systems at additional plants. Oak Ridge National Laboratory has developed a Uranyl Nitrate Calibration Loop Equipment (UNCLE) facility to simulate the full-scale operating conditions for a purified uranium-bearing aqueous stream exiting the solvent extraction process conducted in an NUCP. In addition to calibrating instruments such as the neutron detector developed at Los Alamos National Laboratory, UNCLE will be used to test other in-line instruments (mass and volumetric flowmeters, spectrophotometers, etc.). UNCLE will be able to test commercially available equipment, such as the Endress+Hauser Promass 83F Coriolis meter that was used in the field test and other equipment that is presently under development. UNCLE is designed to accommodate different pipe sizes, flow rates, solution concentrations, and other variables of interest. Construction is expected to be completed by the end of September 2008 with initial testing beginning later that year. The design and current status of UNCLE will be presented, along with the capabilities of the facility and the proposed test plans.

  17. Ultrastructural and metabolic changes in osteoblasts exposed to uranyl nitrate

    Energy Technology Data Exchange (ETDEWEB)

    Tasat, D.R. [Universidad Nacional de San Martin, Escuela de Ciencia y Tecnologia, Pcia de Bs.As. (Argentina); Universidad de Buenos Aires, Catedra de Histologia y Embriologia, Facultad de Odontologia, Buenos Aires (Argentina); Orona, N.S. [Universidad Nacional de San Martin, Escuela de Ciencia y Tecnologia, Pcia de Bs.As. (Argentina); Mandalunis, P.M. [Universidad de Buenos Aires, Catedra de Histologia y Embriologia, Facultad de Odontologia, Buenos Aires (Argentina); Cabrini, R.L. [Comision Nacional de Energia Atomica, Departamento de Radiobiologia, Buenos Aires (Argentina); Ubios, A.M. [Comision Nacional de Energia Atomica, Departamento de Radiobiologia, Buenos Aires (Argentina); Universidad de Buenos Aires, Catedra de Histologia y Embriologia, Facultad de Odontologia, Buenos Aires (Argentina)

    2007-05-15

    Exposure to uranium is an occupational hazard to workers who continually handle uranium and an environmental risk to the population at large. Since the cellular and molecular pathways of uranium toxicity in osteoblast cells are still unknown, the aim of the present work was to evaluate the adverse effects of uranyl nitrate (UN) on osteoblasts both in vivo and in vitro. Herein we studied the osteoblastic ultrastructural changes induced by UN in vivo and analyzed cell proliferation, generation of reactive oxygen species (ROS), apoptosis, and alkaline phosphatase (APh) activity in osteoblasts exposed to various UN concentrations (0.1, 1, 10, and 100 {mu}M) in vitro. Cell proliferation was quantified by means of the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay, ROS was determined using the nitro blue tetrazolium test, apoptosis was morphologically determined using Hoechst 3332 and APh activity was assayed spectrophotometrically. Electron microscopy revealed that the ultrastructure of active and inactive osteoblasts exposed to uranium presented cytoplasmic and nuclear alterations. In vitro, 1-100 {mu}M UN failed to modify cell proliferation ratio and to induce apoptosis. ROS generation increased in a dose-dependent manner in all tested doses. APh activity was found to decrease in 1-100 {mu}M UN-treated cells vs. controls. Our results show that UN modifies osteoblast cell metabolism by increasing ROS generation and reducing APh activity, suggesting that ROS may play a more complex role in cell physiology than simply causing oxidative damage. (orig.)

  18. Dehydration of Uranyl Nitrate Hexahydrate to Uranyl Nitrate Trihydrate under Ambient Conditions as Observed via Dynamic Infrared Reflectance Spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Johnson, Timothy J.; Sweet, Lucas E.; Meier, David E.; Mausolf, Edward J.; Kim, Eunja; Weck, Philippe F.; Buck, Edgar C.; McNamara, Bruce K.

    2015-05-22

    the hexahydrate [UO2(NO3)2(H2O)6] (UNH) and the trihydrate [UO2(NO3)2(H2O)3] (UNT) forms. Their stabilities depend on both relative humidity and temperature. Both phases have previously been studied by infrared transmission spectroscopy, but the data were limited by both instrumental resolution and the ability to prepare the samples as pellets without desiccating them. We report time-resolved infrared (IR) measurements using an integrating sphere that allow us to observe the transformation from the hexahydrate to the trihydrate simply by flowing dry nitrogen gas over the sample. Hexahydrate samples were prepared and confirmed via known XRD patterns, then measured in reflectance mode. The hexahydrate has a distinct uranyl asymmetric stretch band at 949.0 cm-1 that shifts to shorter wavelengths and broadens as the sample dehydrates and recrystallizes to the trihydrate, first as a blue edge shoulder but ultimately resulting in a doublet band with reflectance peaks at 966 and 957 cm-1. The data are consistent with transformation from UNH to UNT since UNT has two non-equivalent UO22+ sites. The dehydration of UO2(NO3)2(H2O)6 to UO2(NO3)2(H2O)3 is both a morphological and structural change that has the lustrous lime green crystals changing to the dull greenish yellow of the trihydrate. Crystal structures and phase transformation were confirmed theoretically using DFT calculations and experimentally via microscopy methods. Both methods showed a transformation with two distinct sites for the uranyl cation in the trihydrate, as opposed to a single crystallographic site in the hexahydrate.

  19. Preparation of thin {alpha}-particle sources using poly-pyrrole films functionalized by a chelating agent; Preparation de sources minces d'emetteurs alpha a l'aide de films de polypyrrole fonctionnalises par un ligand chelatant

    Energy Technology Data Exchange (ETDEWEB)

    Mariet, C. [CEA Saclay, INSTN, Institut National des Sciences et Techniques Nucleaires, 91 - Gif-sur-Yvette (France); Universite Pierre et Marie Curie, 75 - Paris (France)

    2000-07-01

    This work takes place in the scope of analysis of the {alpha}-particle emitting elements U, Pu and Am present in compound environmental matrix like sols and sediments. The samples diversity and above all the {alpha}-ray characteristics require the analyst to implement a sequence of chemical steps in which the more restricting is the actinides concentration in a uniform and thin layer en allowing an accurately measure of alpha activity. On this account, we studied a new technique for radioactive sources preparation based on tow steps: preparation of a thin film as source support; incorporation of radioactive elements by a chelating extraction mechanism. The thin films were obtained through electro-polymerization of pyrrole monomer functionalized by an chelating ligand able to extract actinides from concentrated acidic solutions. Polymerization conditions of this monomer were perfected, then obtained films were characterized from a physico-chemical point of view. We point out their extracting properties were comparable to (retention capacity, distribution coefficient) to those of usual ion-exchange resins. The underscore of uranyl and americium nitrate complexes formed in the thin layer allowed to calculate the extraction constants in case acid extraction is negligible. Thanks to this results, the values of the coefficients distribution D{sub U} and D{sub Am} could be provided for all nitric solutions in which acid extraction is negligible. Optimal actinides retention conditions in the polymer were defined and used to settle a protocol for plutonium analysis in environmental samples. (author)

  20. Synthesis, spectroscopy, and thermal study of uranyl unsymmetrical Schiff base complexes.

    Science.gov (United States)

    Kianfar, Ali Hossein; Dostani, Morteza

    2011-11-01

    The new uranyl complexes with tetradentate unsymmetrical N(2)O(2) Schiff base ligands were synthesized and characterized by IR, UV-vis, NMR and elemental analysis. The DMF solvent is coordinated to uranyl complexes. The thermogravimetry (TG) and differential thermoanalysis (DTA) of the uranyl complexes were carried out in the range of 20-700°C. The UO(2)L(1) complex was decomposed in two and the others were decomposed in three stages. Up to 100°C, the coordinated solvent was released then the Schiff base ligands were decomposed in one or two steps. Decomposition of synthesized complexes is related to the Schiff base characteristics. The thermal decomposition reaction is first order for the studied complexes.

  1. Molecular simulation of the diffusion of uranyl carbonate species in aqueous solution

    Science.gov (United States)

    Kerisit, Sebastien; Liu, Chongxuan

    2010-09-01

    Potential-based molecular dynamics simulations of aqueous uranyl carbonate species (M xUO 2(CO 3) y2+2x-2y with M = Mg, Ca, or Sr) were carried out to gain molecular-level insight into the hydration properties of these species. The simulation results were used to estimate the self-diffusion coefficients of these uranyl carbonate species, which often dominate uranyl speciation in groundwater systems. The diffusion coefficients obtained for the monoatomic alkaline-earth cations and polyatomic ions (uranyl, carbonate, and uranyl tri-carbonate) were compared with those calculated from the Stokes-Einstein (SE) equation and its variant formulation by Impey et al. (1983). Our results show that the equation of Impey et al. (1983), originally formulated for monovalent monoatomic ions, can be extended to divalent monoatomic ions, with some success in reproducing the absolute values and the overall trend determined from the molecular dynamics simulations, but not to polyatomic ions, for which the hydration shell is not spherically symmetrical. Despite the quantitative failure of both SE formulations, a plot of the diffusion coefficients of the uranyl carbonate complexes as a function of the inverse of the equivalent spherical radius showed that a general linear dependence is observed for these complexes as expected from the SE equation. The nature of the alkaline-earth cation in the uranyl carbonate complexes was not found to have a significant effect on the ion's diffusion coefficient, which suggests that the use of a single diffusion coefficient for different alkaline-earth uranyl carbonate complexes in microscopic diffusion models is appropriate. The potential model reproduced well published quantum mechanical and experimental data of UO(CO)32x-4 and of the individual constituent ions, and therefore is expected to offer reliable predictions of the structure of magnesium and strontium uranyl carbonate aqueous species, for which there is no structural data available to date

  2. Selectivity in ligand binding to uranyl compounds: A synthetic, structural, thermodynamic and computational study

    Energy Technology Data Exchange (ETDEWEB)

    Arnold, John [Univ. of California, Berkeley, CA (United States)

    2015-01-21

    The uranyl cation (UO₂²⁺) is the most abundant form of uranium on the planet. It is estimated that 4.5 billion tons of uranium in this form exist in sea water. The ability to bind and extract the uranyl cation from aqueous solution while separating it from other elements would provide a limitless source of nuclear fuel. A large body of research concerns the selective recognition and extraction of uranyl. A stable molecule, the cation has a linear O=U=O geometry. The short U-O bonds (1.78 Å) arise from the combination of uranium 5f/6d and oxygen 2p orbitals. Due to the oxygen moieties being multiply bonded, these sites were not thought to be basic enough for Lewis acidic coordination to be a viable approach to sequestration. The goal of this research is thus to broaden the coordination chemistry of the uranyl ion by studying new ligand systems via synthetic, structural, thermodynamic and computational methods. It is anticipated that this fundamental science will find use beyond actinide separation technologies in areas such as nuclear waste remediation and nuclear materials. The focus of this study is to synthesize uranyl complexes incorporating amidinate and guanidinate ligands. Both synthetic and computational methods are used to investigate novel equatorial ligand coordination and how this affects the basicity of the oxo ligands. Such an understanding will later apply to designing ligands incorporating functionalities that can bind uranyl both equatorially and axially for highly selective sequestration. Efficient and durable chromatography supports for lanthanide separation will be generated by (1) identifying robust peptoid-based ligands capable of binding different lanthanides with variable affinities, and (2) developing practical synthetic methods for the attachment of these ligands to Dowex ion exchange resins.

  3. Removal of uranyl ions by p-hexasulfonated calyx[6]arene acid

    Science.gov (United States)

    Popescu (Hoştuc), Ioana-Carmen; Petru, Filip; Humelnicu, Ionel; Mateescu, Marina; Militaru, Ecaterina; Humelnicu, Doina

    2014-10-01

    Radioactive pollution is a significant threat for the people’s health. Therefore highly effective radioactive decontamination methods are required. Ion exchange, biotechnologies and phytoremediation in constructed wetlands have been used as radioactive decontamination technologies for uranium contaminated soil and water remediation. Recently, beside those classical methods the calix[n]arenic derivatives’ utilization as radioactive decontaminators has jogged attention. The present work aims to present the preliminary research results of uranyl ion sorption studies on the p-hexasulfonated calyx[6]arenic acid. The effect of temperature, contact time, sorbent amount and uranyl concentration variation on sorption efficiency was investigated. Isotherm models revealed that the sorption process fit better Langmuir isotherm.

  4. Removal of uranyl ions by p-hexasulfonated calyx[6]arene acid

    Energy Technology Data Exchange (ETDEWEB)

    Popescu, Ioana-Carmen [R and D National Institute for Metals and Radioactive Resources–ICPMRR, B-dul Carol I No.70, Sector 2, Bucharest 020917 (Romania); Petru, Filip [“C.D. Nenitescu” Institute of Organic Chemistry, Splaiul Independentei 202B, Sector 6, Bucharest 71141 (Romania); Humelnicu, Ionel [“Al.I. Cuza” University of Iasi, The Faculty of Chemistry, Bd. Carol-I No. 11, Iasi 700506 (Romania); Mateescu, Marina [National R and D Institute for Chemistry and Petrochemistry, Splaiul Independenţei No. 202, Bucharest 060021 (Romania); Militaru, Ecaterina [R and D National Institute for Metals and Radioactive Resources–ICPMRR, B-dul Carol I No.70, Sector 2, Bucharest 020917 (Romania); Humelnicu, Doina, E-mail: doinah@uaic.ro [“Al.I. Cuza” University of Iasi, The Faculty of Chemistry, Bd. Carol-I No. 11, Iasi 700506 (Romania)

    2014-10-15

    Radioactive pollution is a significant threat for the people’s health. Therefore highly effective radioactive decontamination methods are required. Ion exchange, biotechnologies and phytoremediation in constructed wetlands have been used as radioactive decontamination technologies for uranium contaminated soil and water remediation. Recently, beside those classical methods the calix[n]arenic derivatives’ utilization as radioactive decontaminators has jogged attention. The present work aims to present the preliminary research results of uranyl ion sorption studies on the p-hexasulfonated calyx[6]arenic acid. The effect of temperature, contact time, sorbent amount and uranyl concentration variation on sorption efficiency was investigated. Isotherm models revealed that the sorption process fit better Langmuir isotherm.

  5. Iron chelating agents for iron overload diseases

    Directory of Open Access Journals (Sweden)

    Guido Crisponi

    2014-09-01

    Full Text Available Although iron is an essential element for life, an excessive amount may become extremely toxic both for its ability to generate reactive oxygen species, and for the lack in humans of regulatory mechanisms for iron excretion. Chelation therapy has been introduced in clinical practice in the seventies of last century to defend thalassemic patients from the effects of iron overload and, in spite of all its limitations, it has dramatically changed both life expectancy and quality of life of patients. It has to be considered that the drugs in clinical use present some disadvantages too, this makes urgent new more suitable chelating agents. The requirements of an iron chelator have been better and better defined over the years and in this paper they will be discussed in detail. As a final point the most interesting ligands studied in the last years will be presented.

  6. Synthesis and complexation properties towards uranyl cation of carboxylic acid derivatives of p-tert-butyl-calix[6]arene; Synthese et proprietes complexantes vis-a-vis de l'ion uranyle de derives carboxyliques du p-tert-butyl-calix[6]arene

    Energy Technology Data Exchange (ETDEWEB)

    Souane, R

    2005-03-15

    In the fuel reprocessing plants radioactive metals, and more particularly, uranium in UO{sub 2}{sup 2+} form in the various installations, have many varied physico-chemical forms and there is a risk of exposure and internal contamination in the nuclear industry. It is necessary to exert a medical control to ensure the protection of the health of the workers. This medical control is done by dosing uranyl cation in the urine of the exposed people. This work forms part of this context. Indeed, we prepared a ligand able to complex the ion uranyl and which is also to be grafted on a solid support. In the family of calixarenes, the calix[6]arenes functionalized by three or four carboxylic functions were selected like chelating molecules of the ion uranyl. The properties of complexation of these calixarenes were studied by potentiometry in methanol, under these conditions balances of protonation and complexation were determined and the constant partners were obtained using the Hyperquad program. We synthesized tri-carboxylic calix[6]arenes comprising of the groupings nitro (NO{sub 2}) in para position of phenol in order to see the influence of a substitution in para position on the complexation. We also synthesized calix[6]arenes tetra-carboxylic in order to show the role of an additional carboxylic acid grouping. The potentiometric study determined thermodynamic parameters of protonation and complexation of carboxylic calix[6]arenes. The results of the complexation highlighted which complex UO{sub 2}L corresponding to the ligand para-tert-butyl-calix[6]arene tetra-acid is more stable than that corresponding to the ligand mono-nitro calix[6]arene tri-acid ({delta}log{beta}110 = 4.3), and than the effect of the groupings nitro in para position has low influence on the complexation of UO{sub 2}{sup 2+}. This makes it possible to consider as possible the grafting of the calix[6]arenes which one knows the behaviour of trapping. To this end we synthesized the ligand 23

  7. Antimitochondrial antibody

    Science.gov (United States)

    ... page: //medlineplus.gov/ency/article/003529.htm Antimitochondrial antibody To use the sharing features on this page, please enable JavaScript. Antimitochondrial antibodies (AMA) are substances ( antibodies ) that form against mitochondria. ...

  8. Study of the extraction mechanisms by TBP saturated by uranyl nitrate; Etude des mecanismes d'extraction du TBP sature par le nitrate d'uranyle

    Energy Technology Data Exchange (ETDEWEB)

    Meze, F

    2004-02-15

    This work deals with a particular phenomenon likely to occur in the nuclear waste reprocessing process PUREX. It was shown earlier by Russian works that the extractant molecule, tributyl phosphate (TBP), saturated by uranyl nitrate keeps its extraction capacities for nitric acid and tetravalent actinides. This study is composed of three parts. Firstly, some liquid-liquid extraction experiments were conducted to verify the ability of TBP saturated by uranyl nitrate to conserve its extraction capacities for nitric acid. Then, during these experiments, the UV and infrared spectra of both phases were recorded to obtain the organic phase speciation. At last, the informations gathered during the experimental part were used to build a general species distribution model of the H{sub 2}O/HNO{sub 3}/UO{sub 2}(NO{sub 3}){sub 2}/TBP system. (author)

  9. Standard test method for isotopic analysis of hydrolyzed uranium hexafluoride and uranyl nitrate solutions by thermal ionization mass spectrometry

    CERN Document Server

    American Society for Testing and Materials. Philadelphia

    2005-01-01

    1.1 This method applies to the determination of isotopic composition in hydrolyzed nuclear grade uranium hexafluoride. It covers isotopic abundance of 235U between 0.1 and 5.0 % mass fraction, abundance of 234U between 0.0055 and 0.05 % mass fraction, and abundance of 236U between 0.0003 and 0.5 % mass fraction. This test method may be applicable to other isotopic abundance providing that corresponding standards are available. 1.2 This test method can apply to uranyl nitrate solutions. This can be achieved either by transforming the uranyl nitrate solution to a uranyl fluoride solution prior to the deposition on the filaments or directly by depositing the uranyl nitrate solution on the filaments. In the latter case, a calibration with uranyl nitrate standards must be performed. 1.3 This test method can also apply to other nuclear grade matrices (for example, uranium oxides) by providing a chemical transformation to uranyl fluoride or uranyl nitrate solution. 1.4 This standard does not purport to address al...

  10. On the retention of uranyl and thorium ions from radioactive solution on peat moss.

    Science.gov (United States)

    Humelnicu, Doina; Bulgariu, Laura; Macoveanu, Matei

    2010-02-15

    The efficiency of the radioactive uranyl and thorium ions on the peat moss from aqueous solutions has been investigated under different experimental conditions. The sorption and desorption of uranyl and thorium ions on three types (unmodified peat moss, peat moss treated with HNO(3) and peat moss treated with NaOH) of peat moss were studied by the static method. Peat moss was selected as it is available in nature, in any amount, as a cheap and accessible sorbent. Study on desorption of such ions led to the conclusion that the most favourable desorptive reagent for the uranyl ions is Na(2)CO(3) 1M while, for the thorium ions is HCl 1M. The results obtained show that the parameters here under investigation exercise a significant effect on the sorption process of the two ions. Also, the investigations performed recommend the peat moss treated with a base as a potential sorbent for the uranyl and thorium ions from a radioactive aqueous solution.

  11. On the bonding and the electric field gradient of the uranyl ion

    NARCIS (Netherlands)

    de Jong, WA; Visscher, L; Nieuwpoort, WC

    1999-01-01

    Molecular properties of the uranyl ion ([UO2](2+)) are studied using both a non-relativistic and a relativistic method. Inclusion of relativity leads to a bond length expansion and makes the electric field gradient (EFG) at the uranium nucleus strongly dependent on the U-O bond distance, The non-rel

  12. Carbonization of solid uranyl-ascorbate gel as an indirect step of uranium carbide synthesis

    Directory of Open Access Journals (Sweden)

    Brykala Marcin

    2015-12-01

    Full Text Available The studies of the synthesis of uranium carbide from uranyl-ascorbate gels using the complex sol-gel process (CSGP have been carried out. The synthesis of uranyl-ascorbate mixture as liquid sol from uranium trioxide and ascorbic acid and solid gel by extraction of water from sol were carefully examined. Ascorbic acid was used as a complexing agent in complex sol-gel process and as a carbon source. The crucial step to obtain final uranium carbides from the aforementioned substrates is the carbonization process. The thermal behavior of ascorbic acid and uranyl-ascorbate gels in a nitrogen atmosphere in the temperature range of 25-900°C were investigated using TG-DTG. Furthermore, the products of the carbonization of uranyl-ascorbate gels in nitrogen, argon and vacuum atmosphere were identified by X-ray diffraction. TG-DTG was used also as a method for determining of carbon residues in the samples.

  13. Removal of uranyl ions from residual waters using some algae types

    NARCIS (Netherlands)

    Cecal, A; Palamaru, [No Value; Humelnicu, D; Popa, K; Salaru, VV; Rudic, [No Value; Gulea, A

    1999-01-01

    This paper deals with a study on the bioaccumulation of uranyl ions resulted from residual effluents by means of some microbiological collectors: Scenedesmus quadricauda, Anabaena karakumica, Calothrix brevissima, Penicillinium sp, as well as the Glucide extract of Porphyridium cruentum, under vario

  14. Nucleobase assemblies supported by uranyl cation coordination and other non-covalent interactions

    Indian Academy of Sciences (India)

    Jitendra Kumar; Sandeep Verma

    2011-11-01

    We describe synthesis and solid state structural description of uranyl complexes of carboxylate functionalized adenine and uracil derivatives. The metal coordination through carboxylate pendant leads to the formation of dimeric assemblies, whereas the directional nature of hydrogen bonding interaction supported by nucleobases and aqua ligands, result in the generation of complex 3-D architectures containing embedded nucleobase ribbons.

  15. Identification of Uranyl Minerals Using Oxygen K-Edge X Ray Absorption Spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Ward, Jesse D.; Bowden, Mark E.; Resch, Charles T.; Smith, Steven C.; McNamara, Bruce K.; Buck, Edgar C.; Eiden, Gregory C.; Duffin, Andrew M.

    2016-03-01

    Uranium analysis is consistently needed throughout the fuel cycle, from mining to fuel fabrication to environmental monitoring. Although most of the world’s uranium is immobilized as pitchblende or uraninite, there exists a plethora of secondary uranium minerals, nearly all of which contain the uranyl cation. Analysis of uranyl compounds can provide clues as to a sample’s facility of origin and chemical history. X-ray absorption spectroscopy is one technique that could enhance our ability to identify uranium minerals. Although there is limited chemical information to be gained from the uranium X-ray absorption edges, recent studies have successfully used ligand NEXAFS to study the physical chemistry of various uranium compounds. This study extends the use of ligand NEXAFS to analyze a suite of uranium minerals. We find that major classes of uranyl compounds (carbonate, oxyhydroxide, silicate, and phosphate) exhibit characteristic lineshapes in the oxygen K-edge absorption spectra. As a result, this work establishes a library of reference spectra that can be used to classify unknown uranyl minerals.

  16. Application of iron chelates in hydrodesulphurisation

    NARCIS (Netherlands)

    Wubs, Harm Jan

    1994-01-01

    Several iron chelate based methods for removing hydrogen sulphide from gas streams have been developed over the years. Notwithstanding the number of hydrodesulphurisation plants already in operation, the development of these processes has been more a kind of an art rather than a result of rational p

  17. Recent developments centered on orally active iron chelators

    Directory of Open Access Journals (Sweden)

    Robert Hider

    2014-09-01

    Full Text Available Over the past twenty years there has been a growing interest in the orally active iron chelators, deferiprone and deferasirox, both have been extensively studied. The ability of these compounds to mobilize iron from the heart and endocrine tissue has presented the clinician with some advantages over desferrioxamine, the first therapeutic iron chelator. Other orally active iron chelators are currently under development. The critical features necessary for the design of therapeutically useful orally active iron chelators are presented in this review, together with recent studies devoted to the design of such chelators. This newly emerging range of iron chelators will enable clinicians to apply iron chelation methodology to other disease states and to begin to design personalized chelation regimes.

  18. Extraction of uranyl nitrate, sulphate and chloride with tri-n-octyl amine (TOA from aqueous solutions

    Directory of Open Access Journals (Sweden)

    DJORDJE M. PETKOVIC

    2001-07-01

    Full Text Available Extraction of uranyl nitrate, chloride and sulphate with tri-n-octyl amine (TOA in benzene as a function of the TOA concentration has been studied. The concentration based extraction equilibrium constants were calculated from the distribution data of the uranyl salts, fitting the parameters of a chemical model to the experimentally obtained extraction isotherms. The calculated equilibrium constants are 46.5, 89.4 and 4.2·104 for uranyl nitrate, chloride and sulphate, respectively. These values are in good agreement with the previously reported extraction equilibrium constants calculated by the inflection point method.

  19. Overview of chelation recommendations for thalassaemia and sickle cell disease

    Directory of Open Access Journals (Sweden)

    Banu Kaya

    2014-12-01

    Full Text Available The long term consequences of iron toxicity are mostly reversible with effective iron chelation therapy. Recommendations for use of chelation therapy in transfusion dependent thalassaemia (TDT, sickle cell disease (SCD and non transfusion dependent thalassaemia (NTDT continue to evolve as our knowledge and clinical experience increases. Improved chelation options including drug combinations and a better understanding of condition specific factors may help to improve efficiency of chelation regimens and meet the needs of patients more effectively.

  20. Uptake of uranyl ions from uranium ores and sludges by means of Spirulina platensis, Porphyridium cruentum and Nostok linckia alga.

    Science.gov (United States)

    Cecal, Alexandru; Humelnicu, Doina; Rudic, Valeriu; Cepoi, Liliana; Ganju, Dumitru; Cojocari, Angela

    2012-08-01

    In this paper was studied the uranyl ions biosorption on three types of alga: Nostok linckia, Porphyridium cruentum and Spirulina platensis. These ions were supplied either from a pure solution of uranyl nitrate, or after leaching process of uranium ore, or from the sludge resulting in the output of pure UO(2) technology. It was investigated the retention degree versus contact time and afterwards the Langmuir and Freundlich biosorption isotherms of uranyl ions on the three alga types. The retention of UO(2)(2+) ions on alga was proved through FTIR spectra plotted before and after biosorption processes. From the experimental data it was found that regardless of origin of uranyl ions, the retention degree on alga decreased in the series. Spirulina platensis > Porphyridium cruentum ≥ Nostok linckia.

  1. Influence of Chelating Agents on Chromium Fate in Sediment

    Institute of Scientific and Technical Information of China (English)

    WANGXIAOCHANG; SUNJINHE; 等

    1996-01-01

    A laboratory investigation on reaction between chelating agents and chromium was conducted to evaluate the effect of chelating agents on the adsorption and desorption of chromium in sediment.The amount of adsorbed chromium(VI) in sediment decreased slightly by 5%-10% because of addition of chelating agents.Chelating agents inhibited the removal of Cr(Ⅲ)by sediment from solutions and the inhibiting effect was in the order:citric acid>tartaric acid>EDTA,Salicylic acid.No effect of chelating agents on desorption of chromium in sediment was observed.

  2. Current recommendations for chelation for transfusion-dependent thalassemia.

    Science.gov (United States)

    Kwiatkowski, Janet L

    2016-03-01

    Regular red cell transfusions used to treat thalassemia cause iron loading that must be treated with chelation therapy. Morbidity and mortality in thalassemia major are closely linked to the adequacy of chelation. Chelation therapy removes accumulated iron and detoxifies iron, which can prevent and reverse much of the iron-mediated organ injury. Currently, three chelators are commercially available--deferoxamine, deferasirox, and deferiprone--and each can be used as monotherapy or in combination. Close monitoring of hepatic and cardiac iron burden is central to tailoring chelation. Other factors, including properties of the individual chelators, ongoing transfusional iron burden, and patient preference, must be considered. Monotherapy generally is utilized if the iron burden is in an acceptable or near-acceptable range and the dose is adjusted accordingly. Combination chelation often is employed for patients with high iron burden, iron-related organ injury, or where adverse effects of chelators preclude administration of an appropriate chelator dose. The combination of deferoxamine and deferiprone is the best studied, but increasing data are available on the safety and efficacy of newer chelator combinations, including deferasirox with deferoxamine and the oral-only combination of deferasirox with deferiprone. The expanding chelation repertoire should enable better control of iron burden and improved outcomes.

  3. Federal regulation of unapproved chelation products.

    Science.gov (United States)

    Lee, Charles E

    2013-12-01

    Chelation products can be helpful in the treatment of metal poisoning. However, many unapproved products with unproven effectiveness and safety are marketed to consumers, frequently via the internet. This paper describes the primary responsibility of the Health Fraud and Consumer Outreach Branch of the United States Food and Drug Administration to identify and address health fraud products. Efforts to prevent direct and indirect hazards to the population's health through regulatory actions are described.

  4. IRON CHELATION THERAPY IN THALASSEMIA SYNDROMES

    Directory of Open Access Journals (Sweden)

    Paolo Cianciulli

    2009-06-01

    Full Text Available Transfusional hemosiderosis is a frequent complication in patients with transfusion dependent chronic diseases such as  thalassemias and severe type of sickle cell diseases. As there are no physiological mechanisms to excrete the iron contained in transfused red cells (1 unit of blood contains approximately 200 mg of iron the excess of iron is stored in various organs. Cardiomyopathy is the most severe complication covering more than 70% of the causes of death of thalassemic patients. Although the current reference standard iron chelator deferoxamine (DFO has been used clinically for over four decades, its effectiveness is limited by a demanding therapeutic regimen that leads to poor compliance. Despite poor compliance, because of the inconvenience of subcutaneous infusion, DFO improved considerably the survival and quality of life of patients with thalassemia. Deferiprone since 1998 and Deferasirox since 2005 were licensed for clinical use. The oral chelators have a better compliance because of oral use, a comparable efficacy to DFO in iron excretion and probably a better penetration to myocardial cells. Considerable increase in iron excretion was documented with combination therapy of DFO and Deferiprone. The proper use of the three chelators will improve the prevention and treatment of iron overload, it will reduce  complications, and improve survival and quality of life of transfused patients

  5. Interaction of aluminum with PHFtau in Alzheimer's disease neurofibrillary degeneration evidenced by desferrioxamine-assisted chelating autoclave method.

    Science.gov (United States)

    Murayama, H; Shin, R W; Higuchi, J; Shibuya, S; Muramoto, T; Kitamoto, T

    1999-09-01

    To demonstrate that aluminum III (Al) interacts with PHFtau in neurofibrillary degeneration (NFD) of Alzheimer's disease (AD) brain, we developed a "chelating autoclave method" that allows Al chelation by using trivalent-cationic chelator desferrioxamine. Its application to AD brain sections before Morin histochemistry for Al attenuated the positive fluorescence of neurofibrillary tangles, indicating Al removal from them. This method, applied for immunostaining with phosphorylation-dependent anti-tau antibodies, significantly enhanced the PHFtau immunoreactivity of the NFD. These results suggest that each of the phosphorylated epitopes in PHFtau are partially masked by Al binding. Incubation of AD sections with AlCl(3) before Morin staining revealed Al accumulation with association to neurofibrillary tangles. Such incubation before immunostaining with the phosphorylation-dependent anti-tau antibodies abolished the immunolabeling of the NFD and this abolition was reversed by the Al chelation. These findings indicate cumulative Al binding to and thereby antigenic masking of the phosphorylated epitopes of PHFtau. Al binding was further documented for electrophoretically-resolved PHFtau on immunoblots, indicating direct Al binding to PHFtau. In vitro aggregation by AlCl(3) was observed for PHFtau but was lost on dephosphorylation of PHFtau. Taken together, phosphorylation-dependent and direct PHFtau-Al interaction occurs in the NFD of the AD brain.

  6. Effect of uranyl intoxication on renal corticomedullary gradient of orthoiodohippurate in laboratory rat

    Energy Technology Data Exchange (ETDEWEB)

    Vlcek, J.; Kvetina, J. (Karlova Univ., Hradec Kralove (Czechoslovakia). Farmaceuticka Fakulta)

    1983-08-05

    The assessment is attempted of the intrarenal distribution (by means of the cortico-medullary gradient and the cortico-pelvic gradient) of a model diagnostic substance (O-/sup 125/I-hippurate) for the analysis of mechanisms causing damage to the renal function during intoxication induced by uranyl ions (uranyl nitrate). The findings were correlated with other indicators of the renal lesion (creatinine and urea plasma levels). Relative shifts of different gradients, i.e. mutual shifts and shifts in relation to hippurate blood levels, make it possible to describe the stepwise character of functional changes in the damaged kidney. The method used is suitable for investigating the dynamics of substances transport during functional renal changes in particular when combined with the determination the intensity of the uptake of model substances by renal tissue slices.

  7. DFT studies of uranyl acetate, carbonate, and malonate, complexes in solution.

    Science.gov (United States)

    Vázquez, Jordi; Bo, Carles; Poblet, Josep Maria; de Pablo, Joan; Bruno, Jordi

    2003-09-22

    The aim of this work is to demonstrate that theoretical chemistry can be used as a complementary tool in determining geometric parameters of a number of uranyl complexes in solution, which are not observable by experimental methods. In addition, we propose plausible structures with partial geometric data from experimental results. A gradient corrected DFT methodology with relativistic effects is used employing a COSMO solvation model. The theoretical calculations show good agreement with experimental X-ray and EXAFS data for the triacetato-dioxo-uranium(VI) and tricarbonato-dioxo-uranium(VI) complexes and are used to assign possible geometries for dicalcium-tricarbonato-dioxo-uranium(VI) and malonato-dioxo-uranium(VI) complexes. The results of this exercise indicate that carbonate bonding in these complexes is mainly bidentate and that hydroxo bridging plays a critical role in the stabilization of the polynuclear uranyl complexes.

  8. Spectroscopic study on uranyl carboxylate complexes formed at the surface layer of Sulfolobus acidocaldarius.

    Science.gov (United States)

    Reitz, Thomas; Rossberg, Andre; Barkleit, Astrid; Steudtner, Robin; Selenska-Pobell, Sonja; Merroun, Mohamed L

    2015-02-14

    The complexation of U(vi) at the proteinaceous surface layer (S-layer) of the archaeal strain Sulfolobus acidocaldarius was investigated over a pH range from pH 1.5 to 6 at the molecular scale using time-resolved laser-induced fluorescence spectroscopy (TRLFS) and U L(III)-edge extended X-ray absorption fine structure (EXAFS). The S-layer, which represents the interface between the cell and its environment, is very stable against high temperatures, proteases, and detergents. This allowed the isolation and purification of S-layer ghosts (= empty cells) that maintain the size and shape of the cells. In contrast to many other microbial cell envelope compounds the studied S-layer is not phosphorylated, enabling the investigation of uranyl carboxylate complexes formed at microbial surfaces. The latter are usually masked by preferentially formed uranyl phosphate complexes. We demonstrated that at highly acidic conditions (pH 1.5 to 3) no uranium was bound by the S-layer. In contrast to that, at moderate acidic pH conditions (pH 4.5 and 6) a complexation of U(vi) at the S-layer via deprotonated carboxylic groups was stimulated. Titration studies revealed dissociation constants for the carboxylic groups of glutamic and aspartic acid residues of pK(a) = 4.78 and 6.31. The uranyl carboxylate complexes formed at the S-layer did not show luminescence properties at room temperature, but only under cryogenic conditions. The obtained luminescence maxima are similar to those of uranyl acetate. EXAFS spectroscopy demonstrated that U(vi) in these complexes is mainly coordinated to carboxylate groups in a bidentate binding mode. The elucidation of the molecular structure of these complexes was facilitated by the absence of phosphate groups in the studied S-layer protein.

  9. Coordination mode of nitrate in uranyl(VI) complexes: a first-principles molecular dynamics study.

    Science.gov (United States)

    Bühl, Michael; Diss, Romain; Wipff, Georges

    2007-06-25

    According to Car-Parrinello molecular dynamics simulations for [UO(2)(NO(3))(3)](-), [UO(2)(NO(3))(4)](2-), and [UO(2)(OH(2))(4-)(NO(3))](+) complexes in the gas phase and in aqueous solution, the nitrate coordination mode to uranyl depends on the interplay between ligand-metal attractions, interligand repulsions, and solvation. In the trinitrate, the eta(2)-coordination is clearly favored in water and in the gas phase, leading to a coordination number (CN) of 6. According to pointwise thermodynamic integration involving constrained molecular dynamics simulations, a change in free energy of +6 kcal/mol is predicted for eta(2)- to eta(1)-transition of one of the three nitrate ligands in the gas phase. In the gas phase, the mononitrate-hydrate complex also prefers a eta(2)-binding mode but with a CN of 5, one H(2)O molecule being in the second shell. This contrasts with the aqueous solution where the nitrate binds in a eta(1)-fashion and uranyl coordinates to four H2O ligands. A driving force of ca. -3 kcal/mol is predicted for the eta(2)- to eta(1)- transition in water. This structural preference is interpreted in terms of steric arguments and differential solvation of terminal vs uranyl-coordinated O atoms of the nitrate ligands. The [UO(2)(NO(3))(4)](2-) complex with two eta(2)- and two eta(1)- coordinated nitrates, observed in the solid state, is stable for 1-2 ps in the gas phase and in solution. In the studied series, the modulation of uranyl-ligand distances upon immersion of the complex in water is found to depend on the nature of the ligand and the composition of the complex.

  10. Determination of uranyl incorporation into biogenic manganese oxides using X-ray absorption spectroscopy and scattering

    Science.gov (United States)

    Webb, S.M.; Fuller, C.C.; Tebo, B.M.; Bargar, J.R.

    2006-01-01

    Biogenic manganese oxides are common and an important source of reactive mineral surfaces in the environment that may be potentially enhanced in bioremediation cases to improve natural attenuation. Experiments were performed in which the uranyl ion, UO22+ (U(VI)), at various concentrations was present during manganese oxide biogenesis. At all concentrations, there was strong uptake of U onto the oxides. Synchrotron-based extended X-ray absorption fine structure (EXAFS) spectroscopy and X-ray diffraction (XRD) studies were carried out to determine the molecular-scale mechanism by which uranyl is incorporated into the oxide and how this incorporation affects the resulting manganese oxide structure and mineralogy. The EXAFS experiments show that at low concentrations (2 mol % U, >4 ??M U(VI) in solution), the presence of U(VI) affects the stability and structure of the Mn oxide to form poorly ordered Mn oxide tunnel structures, similar to todorokite. EXAFS modeling shows that uranyl is present in these oxides predominantly in the tunnels of the Mn oxide structure in a tridentate complex. Observations by XRD corroborate these results. Structural incorporation may lead to more stable U(VI) sequestration that may be suitable for remediation uses. These observations, combined with the very high uptake capacity of the Mn oxides, imply that Mn-oxidizing bacteria may significantly influence dissolved U(VI) concentrations in impacted waters via sorption and incorporation into Mn oxide biominerals. ?? 2006 American Chemical Society.

  11. A cryogenic fluorescence spectroscopic study of uranyl carbonate, phosphate and oxyhydroxide minerals

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Z.; Zachara, J.M.; Liu, C.; Gassman, P.L.; Felmy, A.R. [Pacific Northwest National Lab., Richland, WA (United States); Clark, S.B. [Washington State Univ., Pullman, WA (United States)

    2008-07-01

    In this work we applied time-resolved laser-induced fluorescence spectroscopy (TRLIF) at both room temperature (RT) and near liquid-helium temperature (6 K) to characterize a series of natural and synthetic minerals of uranium carbonate, phosphate and oxyhydroxides including rutherfordine, zellerite, liebigite, phosphuranylite, meta-autunite, meta-torbernite, uranyl phosphate, sodium-uranyl-phosphate, becquerelite, schoepite, meta-schoepite, dehydrated schoepite and compreignacite, and have compared the spectral characteristics among these minerals as well as our previously published data on uranyl silicates. For the carbonate minerals, the fluorescence spectra of rutherfordine showed significant difference from those of zellerite and liebigite. The fluorescence spectra of the phosphate minerals closely resemble each other despite the differences in their composition and structure. For all uranium oxyhydroxides, the fluorescence spectra are largely red-shifted as compared to those of the uranium carbonates and phosphates and their vibronic bands are broad and less resolved at RT. The enhanced spectra resolution at 6 K allows more accurate determination of the fluorescence band origin and offers a complemental method to measure the O=U=O symmetrical stretch frequency, {nu}{sub 1}, from the spacings of the vibronic bands of the fluorescence spectra. The average {nu}{sub 1} values appear to be inversely correlated with the average pK{sub a} values of the anions. (orig.)

  12. A cryogenic fluorescence spectroscopic study of uranyl carbonate, phosphate, and oxyhydroxide minerals

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Zheming; Zachara, John M.; Liu, Chongxuan; Gassman, Paul L.; Felmy, Andrew R.; Clark, Sue B.

    2008-11-03

    In this work we have applied liquid-helium temperature (LHeT) time-resolved laser-induced fluorescence spectroscopy (TRLIF) to characterize a series of natural and synthetic minerals of uranium carbonate, phosphate and oxyhydroxides including rutherfordine, zellerite, liebigite, phosphuranylite, meta-autunite, meta-torbernite, uranyl phosphate, sodium-uranyl-phosphate, bequerelite, clarkeite, curite, schoepite and compregnacite, and compared their spectral characteristics among these minerals as well as our previously published data on uranyl silicates. For the carbonate minerals, the fluorescence spectra depend on the stoichiometry of the mineral. For the phosphate minerals the fluorescence spectra closely resemble each other despite the differences in their composition and structure. For all uranium oxyhydroxides, the fluorescence spectra are largely red-shifted as compared with those of the uranium carbonates and phosphates and their vibronic bands are broadened and less resolved. The much enhanced spectra resolution at LHeT allows more accurate calculation of the O=U=O symmetrical stretch frequency, ν1, corresponding to the average spacing of the vibronic peaks of the fluorescence spectra and the spectral origin as reflected by the position of the first vibronic band. It was found that both the average ν1 and λ1 values correlate well with the average basicity of the inorganic anion.

  13. A relativistic density functional study of uranyl hydrolysis and complexation by carboxylic acids in aqueous solution

    Energy Technology Data Exchange (ETDEWEB)

    Ray, Rupashree Shyama

    2009-02-10

    In this work, the complexation of uranium in its most stable oxidation state VI in aqueous solution was studied computationally, within the framework of density functional (DF) theory. The thesis is divided into the following parts: Chapter 2 briefly summarizes the relevant general aspects of actinide chemistry and then focuses on actinide environmental chemistry. Experimental results on hydrolysis, actinide complexation by carboxylic acids, and humic substances are presented to establish a background for the subsequent discussion. Chapter 3 describes the computational method used in this work and the relevant features of the parallel quantum chemistry code PARAGAUSS employed. First, the most relevant basics of the applied density functional approach are presented focusing on relativistic effects. Then, the treatment of solvent effects, essential for an adequate modeling of actinide species in aqueous solution, will be introduced. At the end of this chapter, computational parameters and procedures will be summarized. Chapter 4 presents the computational results including a comparison to available experimental data. In the beginning, the mononuclear hydrolysis product of UO{sub 2}{sup 2+}, [UO{sub 2}OH]{sup +}, will be discussed. The second part deals with actinide complexation by carboxylate ligands. First of all the coordination number for uranylacetate will be discussed with respect to implications for the complexation of actinides by humic substances followed by the uranyl complexation of aromatic carboxylic acids in comparison to earlier results for aliphatic ones. In the end, the ternary uranyl-hydroxo-acetate are discussed, as models of uranyl humate complexation at ambient condition.

  14. Gas-phase reactions of molecular oxygen with uranyl(V) anionic complexes-synthesis and characterization of new superoxides of uranyl(VI).

    Science.gov (United States)

    Lucena, Ana F; Carretas, José M; Marçalo, Joaquim; Michelini, Maria C; Gong, Yu; Gibson, John K

    2015-04-16

    Gas-phase complexes of uranyl(V) ligated to anions X(-) (X = F, Cl, Br, I, OH, NO3, ClO4, HCO2, CH3CO2, CF3CO2, CH3COS, NCS, N3), [UO2X2](-), were produced by electrospray ionization and reacted with O2 in a quadrupole ion trap mass spectrometer to form uranyl(VI) anionic complexes, [UO2X2(O2)](-), comprising a superoxo ligand. The comparative rates for the oxidation reactions were measured, ranging from relatively fast [UO2(OH)2](-) to slow [UO2I2](-). The reaction rates of [UO2X2](-) ions containing polyatomic ligands were significantly faster than those containing the monatomic halogens, which can be attributed to the greater number of vibrational degrees of freedom in the polyatomic ligands to dissipate the energy of the initial O2-association complexes. The effect of the basicity of the X(-) ligands was also apparent in the relative rates for O2 addition, with a general correlation between increasing ligand basicity and O2-addition efficiency for polyatomic ligands. Collision-induced dissociation of the superoxo complexes showed in all cases loss of O2 to form the [UO2X2](-) anions, indicating weaker binding of the O2(-) ligand compared to the X(-) ligands. Density functional theory computations of the structures and energetics of selected species are in accord with the experimental observations.

  15. Novel Terbium Chelate Doped Fluorescent Silica Nanoparticles

    Institute of Scientific and Technical Information of China (English)

    Ning Qiaoyu; Meng Jianxin; Wang Haiming; Liu Yingliang; Man Shiqing

    2006-01-01

    Novel terbium chelate doped silica fluorescent nanoparticles were prepared and characterized.The preparation was carried out in water-in-oil (W/O) microemulsion containing monomer precursor (pAB-DTPAA-APTEOS), Triton X-100, n-hexanol, and cyclohexane by controlling copolymerization of tetraethyl orthosilicate and 3-aminopropyl-triethyloxysilane.The nanoparticles are spherical and uniform in size, about 30 nm in diameter, strongly fluorescent, and highly stable.The amino groups directly introduced to the surface of the nanoparticles using APTEOS during preparation made the surface modification and bioconjugation of the nanoparticles easier.The nanoparticles are expected as an efficient time-resolved luminescence biological label.

  16. Progress on Study of Luminescence of Rare Earth Organic Chelates

    Institute of Scientific and Technical Information of China (English)

    杨燕生; 安保礼; 龚孟濂; 史华红; 雷衡毅; 孟建新

    2002-01-01

    Based on the investigation of the luminescence of a series of rare earth organic chelates, some relationships between luminescence and the structure of the chelates were proposed: the intensity of sensitized luminescence of central lanthanide ions(Ln3+) in a rare earth organic chelate depends on (1)the suitability of the energy gap between the excited triplet energy level of the ligands and the lowest excited energy level of Ln3+ ions; (2)the rigidity and planarity of the structure of the chelate molecule; (3)the existence of a suitable secondary ligand which may increase rigidity and the stability of the chelate molecule; and (4) the existence of a suitable π-conjugated system in the chelate molecule. According to the above relationships, 25 novel organic ligands were designed and synthesized, and their lanthanide chelates were prepared. Investigation of the photoluminescence for the new chelates shows that some of the chelates are strongly luminescent, and are applied to fluoroimmunoassay for determination of human immunoglobulin(IgG), to preparation of fluorescent plastics, and to determination of growth hormone for plants. Two novel spectroscopy-probe techniques for structure of coordination compounds and biological molecules were proposed and developed based on vibronic spectroscopy of Tb3+ complexes and fluorescence of Ce3+.

  17. Metal regeneration of iron chelates in nitric oxide scrubbing

    Science.gov (United States)

    Chang, S.G.; Littlejohn, D.; Shi, Y.

    1997-08-19

    The present invention relates to a process of using metal particles to reduce NO to NH{sub 3}. More specifically, the invention concerns an improved process to regenerate iron (II) (CHELATE) by reduction of iron (II) (CHELATE) (NO) complex, which process comprises: (a) contacting an aqueous solution containing iron (II) (CHELATE) (NO) with metal particles at between about 20 and 90 C to reduce NO present, produce ammonia or an ammonium ion, and produce free iron (II) (CHELATE) at a pH of between about 3 and 8. The process is useful to remove NO from flue gas and reduce pollution. 34 figs.

  18. Myelodysplastic Syndromes and Iron Chelation Therapy

    Science.gov (United States)

    Angelucci, Emanuele; Urru, Silvana Anna Maria; Pilo, Federica; Piperno, Alberto

    2017-01-01

    Over recent decades we have been fortunate to witness the advent of new technologies and of an expanded knowledge and application of chelation therapies to the benefit of patients with iron overload. However, extrapolation of learnings from thalassemia to the myelodysplastic syndromes (MDS) has resulted in a fragmented and uncoordinated clinical evidence base. We’re therefore forced to change our understanding of MDS, looking with other eyes to observational studies that inform us about the relationship between iron and tissue damage in these subjects. The available evidence suggests that iron accumulation is prognostically significant in MDS, but levels of accumulation historically associated with organ damage (based on data generated in the thalassemias) are infrequent. Emerging experimental data have provided some insight into this paradox, as our understanding of iron-induced tissue damage has evolved from a process of progressive bulking of organs through high-volumes iron deposition, to one of ‘toxic’ damage inflicted through multiple cellular pathways. Damage from iron may, therefore, occur prior to reaching reference thresholds, and similarly, chelation may be of benefit before overt iron overload is seen. In this review, we revisit the scientific and clinical evidence for iron overload in MDS to better characterize the iron overload phenotype in these patients, which differs from the classical transfusional and non-transfusional iron overload syndrome. We hope this will provide a conceptual framework to better understand the complex associations between anemia, iron and clinical outcomes, to accelerate progress in this area. PMID:28293409

  19. Europium(III) chelate-dyed nanoparticles as donors in a homogeneous proximity-based immunoassay for estradiol

    Energy Technology Data Exchange (ETDEWEB)

    Kokko, Leena; Sandberg, Kaisa; Loevgren, Timo; Soukka, Tero

    2004-02-09

    Nanoparticles containing thousands of fluorescent europium(III) chelates have a very high specific activity compared to traditional lanthanide chelate labels. It can be assumed that if these particles are used in a homogeneous assay as donors, multiple chelates can excite a single acceptor in turns and the energy transfer to the acceptor is increased. The principle was employed in an immunoassay using luminescent resonance energy transfer from a long lifetime europium(III) chelate-dyed nanoparticle to a short lifetime, near-infrared fluorescent molecule. Due to energy transfer fluorescence lifetime of the sensitised emission was prolonged and fluorescence could be measured using a time-resolved detection. A competitive homogeneous immunoassay for estradiol was created using 92 nm europium(III) chelate-dyed nanoparticle coated with 17{beta}-estradiol specific recombinant antibody Fab fragments as a donor and estradiol conjugated with near-infrared dye AlexaFluor 680 as an acceptor. The density of Fab fragments on the surface of the particle influenced the sensitivity of the immunoassay. The optimal Fab density was reached when the entire surface of the particle participated in the energy transfer, but the areas where the energy was transferred to a single acceptor, did not overlap. We were able to detect estradiol concentrations down to 70 pmol l{sup -1} (3xSD of a standard containing 0 nmol l{sup -1} of E2) using a 96-well platform. In this study we demonstrated that nanoparticles containing lanthanide chelates could be used as efficient donors in homogeneous assays.

  20. Selective recognition of uranyl ions from bulk of thorium(iv) and lanthanide(iii) ions by tetraalkyl urea: a combined experimental and quantum chemical study.

    Science.gov (United States)

    Vats, Bal Govind; Das, Debasish; Sadhu, Biswajit; Kannan, S; Pius, I C; Noronha, D M; Sundararajan, Mahesh; Kumar, Mukesh

    2016-06-21

    The selective separation of uranyl ions from an aqueous solution is one of the most important criteria for sustainable nuclear energy production. We report herein a known, but unexplored extractant, tetraalkyl urea, which shows supreme selectivity for uranium in the presence of interfering thorium and other lanthanide ions from a nitric acid medium. The structural characterization of the uranyl complex (UO2X2·2L, where X = NO3(-), Cl(-) and Br(-)) by IR, NMR and single crystal X-ray diffraction provides insight into the strong interaction between the uranyl ion and the ligand. The origin of this supreme selectivity for uranyl ions is further supported by electronic structure calculations. Uranyl binding with the extractant is thermodynamically more favourable when compared to thorium and the selectivity is achieved through a combination of electronic and steric effects.

  1. Chelation Treatment for Autism Spectrum Disorders: A Systematic Review

    Science.gov (United States)

    Davis, Tonya N.; O'Reilly, Mark; Kang, Soyeon; Lang, Russell; Rispoli, Mandy; Sigafoos, Jeff; Lancioni, Giulio; Copeland, Daelynn; Attai, Shanna; Mulloy, Austin

    2013-01-01

    Chelation treatment is used to eliminate specific metals from the body, such as mercury. It has been hypothesized that mercury poisoning may be a factor in autism and data suggest that perhaps 7% of individuals with autism spectrum disorder (ASD) have received chelation treatment. It would therefore seem timely to review studies investigating the…

  2. Potentials and drawbacks of chelate-enhanced phytoremediation of soils

    NARCIS (Netherlands)

    Römkens, P.F.A.M.; Bouwman, L.A.; Japenga, J.; Draaisma, C.

    2002-01-01

    Chelate-enhanced phytoremediation has been proposed as an effective tool for the extraction of heavy metals from soils by plants. However, side-effects related to the addition of chelates, e.g. metal leaching and effects on soil micro-organisms, were usually neglected. Therefore, greenhouse and lysi

  3. FY-15 Progress Report on Cleanup of irradiated SHINE Target Solutions Containing 140g-U/L Uranyl Sulfate

    Energy Technology Data Exchange (ETDEWEB)

    Bennett, Megan E. [Argonne National Lab. (ANL), Argonne, IL (United States); Bowers, Delbert L. [Argonne National Lab. (ANL), Argonne, IL (United States); Vandegrift, George F. [Argonne National Lab. (ANL), Argonne, IL (United States)

    2015-09-01

    During FY 2012 and 2013, a process was developed to convert the SHINE Target Solution (STS) of irradiated uranyl sulfate (140 g U/L) to uranyl nitrate. This process is necessary so that the uranium solution can be processed by the UREX (Uranium Extraction) separation process, which will remove impurities from the uranium so that it can be recycled. The uranyl sulfate solution must contain <0.02 M SO42- so that the uranium will be extractable into the UREXsolvent. In addition, it is desired that the barium content be below 0.0007 M, as this is the limit in the Resource Conservation and Recovery Act (RCRA).

  4. Treating Lead Toxicity: Possibilities beyond Synthetic Chelation

    Directory of Open Access Journals (Sweden)

    Shambhavi Tannir

    2013-01-01

    Full Text Available Lead, a ubiquitous metal, is one of the most abundant elements present on earth. Its easy availability and cost effectiveness made it an extremely popular component in the industrial revolution. However, its hazardous health effects were not considered at the time. Over the last few decades, with the adverse effects of lead coming to the forefront, nations across the world have started to recognize and treat lead toxicity. The most reliable and used method until now has been chelation therapy. Recent research has suggested the use of natural products and sources to treat lead poisoning with minimal or no side effects. This review has tried to summarize a few of the natural products/sources being investigated by various groups.

  5. Quantitative measurement of metal chelation by fourier transform infrared spectroscopy

    Directory of Open Access Journals (Sweden)

    Monika E. Miller

    2015-12-01

    Full Text Available Nutritionally important minerals are more readily absorbed by living systems when complexed with organic acids, resulting in higher consumer demand and premium prices for these products. These chelated metals are produced by reaction of metal oxides and acids in aqueous solution. However, unreacted dry blends are sometimes misrepresented as metal chelates, when in reality they are only simple mixtures of the reactants typically used to synthesize them. This practice has increased interest in developing analytical methods that are capable of measuring the extent of metal chelation for quality control and regulatory compliance. We describe a novel method to rapidly measure the percent chelation of citric and malic acids with calcium, magnesium, and zinc. Utilization of attenuated total reflectance (FTIR-ATR provides for the direct, rapid measurement of solid samples. The inclusion of an internal standard allows independent determination of either free or chelated acids from integrated areas in a single spectrum.

  6. Luminescence of a conjugated polymer containing europium (III) chelate

    Energy Technology Data Exchange (ETDEWEB)

    Liang, Hao; Xie, Fang, E-mail: xiefang4498@126.com

    2013-12-15

    A europium (III) chelate has been incorporated in a conjugated polymer, poly-[2,2′-bipyridine-5,5′-diyl-(2,5-dihexyl-1,4-phenylene)]. From the absorbance and emission spectra measurement and using the Judd–Ofelt theory, an efficient energy transfer between the conjugated polymer and the europium (III) chelate has been confirmed. The luminescence lifetime of Eu{sup 3+} ion in the conjugated polymer is 0.352 ms and the emission cross section of this material is 3.11×10{sup −21} cm{sup 2}. -- Highlights: • A europium chelate has been incorporated in a conjugated polymer. • Energy transfer in the conjugated polymer containing europium chelate is efficient. • The conjugated polymer containing europium chelate is a promising optical material.

  7. Chelating ionic liquids for reversible zinc electrochemistry.

    Science.gov (United States)

    Kar, Mega; Winther-Jensen, Bjorn; Forsyth, Maria; MacFarlane, Douglas R

    2013-05-21

    Advanced, high energy-density, metal-air rechargeable batteries, such as zinc-air, are of intense international interest due to their important role in energy storage applications such as electric and hybrid vehicles, and to their ability to deal with the intermittency of renewable energy sources such as solar and wind. Ionic liquids offer a number of ideal thermal and physical properties as potential electrolytes in such large-scale energy storage applications. We describe here the synthesis and characterisation of a family of novel "chelating" ILs designed to chelate and solubilize the zinc ions to create electrolytes for this type of battery. These are based on quaternary alkoxy alkyl ammonium cations of varying oligo-ether side chains and anions such as p-toluene sulfonate, bis(trifluoromethylsulfonyl)amide and dicyanoamides. This work shows that increasing the ether chain length in the cation from two to four oxygens can increase the ionic conductivity and reduce the melting point from 67 °C to 15 °C for the tosylate system. Changing the anion also plays a significant role in the nature of the zinc deposition electrochemistry. We show that zinc can be reversibly deposited from [N(222(20201))][NTf2] and [N(222(202020201))][NTf2] beginning at -1.4 V and -1.7 V vs. SHE, respectively, but not in the case of tosylate based ILs. This indicates that the [NTf2] is a weaker coordinating anion with the zinc cation, compared to the tosylate anion, allowing the coordination of the ether chain to dominate the behavior of the deposition and stripping of zinc ions.

  8. Relationship between conformational flexibility and chelate cooperativity.

    Science.gov (United States)

    Misuraca, M Cristina; Grecu, Tudor; Freixa, Zoraida; Garavini, Valentina; Hunter, Christopher A; van Leeuwen, Piet W N M; Segarra-Maset, M Dolores; Turega, Simon M

    2011-04-15

    A family of four biscarbamates (AA) and four bisphenols (DD) were synthesized, and H-bonding interactions between all AA•DD combinations were characterized using (1)H NMR titrations in carbon tetrachloride. A chemical double mutant cycle analysis shows that there are no secondary electrostatic interactions or allosteric cooperativity in these systems, and the system therefore provides an ideal platform for investigating the relationship between chemical structure and chelate cooperativity. Effective molarities (EMs) were measured for 12 different systems, where the number of rotors in the chains connecting the two H-bond sites was varied from 5 to 20. The association constants vary by less than an order of magnitude for all 12 complexes, and the variation in EM is remarkably small (0.1-0.9 M). The results provide a relationship between EM and the number of rotors in the connecting chains (r): EM ≈ 10r(-3/2). The value of 10 M is the upper limit for the value of EM for a noncovalent intramolecular interaction. Introduction of rotors reduces the value of EM from this maximum in accord with a random walk analysis of the encounter probability of the chain ends (r(-3/2)). Noncovalent EMs never reach the very high values observed for covalent processes, which places limitations on the magnitudes of the effects that one is likely to achieve through the use of chelate cooperativity in supramolecular assembly and catalysis. On the other hand, the decrease in EM due to the introduction of conformational flexibility is less dramatic than one might expect based on the behavior of covalent systems, which limits the losses in binding affinity caused by poor preorganization of the interaction sites.

  9. Selective Se-for-S substitution in Cs-bearing uranyl compounds

    Science.gov (United States)

    Gurzhiy, Vladislav V.; Tyumentseva, Olga S.; Krivovichev, Sergey V.; Tananaev, Ivan G.

    2017-04-01

    Phase formation in the mixed sulfate-selenate aqueous system of uranyl nitrate and cesium nitrate has been investigated. Two types of crystalline compounds have been obtained and characterized using a number of experimental (single crystal XRD, FTIR, SEM) and theoretical (information-based complexity calculations, topological analysis) techniques. No miscibility gaps have been observed for Cs2[(UO2)2(TO4)3] (T= S, Se), which crystallizes in tetragonal system, P-421m, a =9.616(1)-9.856(2), c =8.105(1)-8.159(1) Å, V =749.6(2)-792.5(3) Å3. Nine phases with variable amount of S and Se have been structurally characterized. The structures of the Cs2[(UO2)2(TO4)3] (T= S, Se) compounds are based upon the [(UO2)2(TO4)3]2- layers of corner-sharing uranyl pentagonal bipyramids and TO4 tetrahedra. The layers contain two types of tetrahedral sites: T1 (3-connected, i.e. having three O atoms shared by adjacent uranyl polyhedra) and T2 (4-connected). The Se-for-S substitution in tetrahedral sites is highly selective with smaller S6+ cation showing a strong preference for the more tightly bonded T2 site. Crystallization in the pure Se system starts with the formation of Cs2[(UO2)(SeO4)2(H2O)](H2O) crystals, its subsequent dissolution and formation of Cs2[(UO2)2(SeO4)3]. The information-based structural complexity calculations for these two phases support the rule that more topologically complex structures form at the latest stages of crystallization.

  10. Fixation kinetics of chelated and non-chelated zinc in semi-arid alkaline soils: application to zinc management

    Science.gov (United States)

    Udeigwe, Theophilus K.; Eichmann, Madeleine; Menkiti, Matthew C.

    2016-07-01

    This study was designed to examine the fixation pattern and kinetics of zinc (Zn) in chelated (ethylenediaminetetraacetic acid, EDTA) and non-chelated mixed micronutrient systems of semi-arid alkaline soils from the Southern High Plains, USA. Soils were characterized for a suite of chemical and physical properties and data obtained from extraction experiments fitted to various kinetic models. About 30 % more plant-available Zn was fixed in the non-chelated system within the first 14 days with only about 18 % difference observed between the two systems by day 90, suggesting that the effectiveness of the chelated compounds tended to decrease over time. The strengths of the relationships of change in available Zn with respect to other micronutrients (copper, iron, and manganese) were higher and more significant in the non-chelated system (average R2 of 0.83), compared to the chelated (average R2 of 0.42). Fixation of plant-available Zn was best described by the power-function model (R2 = 0.94, SE = 0.076) in the non-chelated system, and was poorly described by all the models examined in the chelated system. Reaction rate constants and relationships generated from this study can serve as important tools for micronutrient management and for future micronutrient modeling studies on these soils and other semi-arid regions of the world.

  11. Synthesis, characterization and photo luminescence studies of uranyl doped SrBPO{sub 5}

    Energy Technology Data Exchange (ETDEWEB)

    Rout, Annapurna; Suriyamurthy, N.; Panigrahi, B. S., E-mail: bsp@igcar.gov.in [Indira Gandhi Centre for Atomic Research, Kalpakkam – 603 102 (India)

    2015-06-24

    SrBPO{sub 5}: UO{sub 2}{sup 2+} was synthesized using solid state reaction method and characterized using powder X-ray diffraction. PXRD data showed the formation of single phase confirming successful doping of UO{sub 2}{sup 2+}. Photo luminescence investigation informed stabilization of Uranium as Uranyl (UO{sub 2}{sup 2+}) in SrBPO{sub 5} matrix. Luminescence decay time data suggested two possible environments for UO{sub 2}{sup 2+} with two different life time values.

  12. New complexes of heteroaromatic N-oxides with europium, uranyl and zinc ions

    Institute of Scientific and Technical Information of China (English)

    Zbigniew Hnatejko

    2012-01-01

    New solid complexes of europium,uranyl and zinc ions with N-oxides of 4-chloro-2,6-dimethylpyridine,quinoline and 4-methoxyquinaldinic acid in presence different anions were obtained and characterized by elemental and TG analyses,IR and luminescence spectra.The compounds are crystalline,hydrated or anhydrous salts with colours typical of metal ions.Thermal studies showed that in hydrated salts lattice or coordination water molecules are present.A role of different anions in the formation of various types of the complexes is presented.

  13. Thermal Analysis of the Decomposition of Ammonium Uranyl Carbonate (AUC) in Different Atmospheres

    DEFF Research Database (Denmark)

    Hälldahl, L.; Sørensen, Ole Toft

    1979-01-01

    The intermediate products formed during thermal decomposition of ammonium uranyl carbonate (AUC) in different atmospheres, (air, helium and hydrogen) have been determined by thermal analysis, (TG, and DTA) and X-ray analysis. The endproducts observed are U3O8 and UO2 in air/He and hydrogen, respe......, respectively. The following intermediate products were observed in all atmospheres: http://www.sciencedirect.com.globalproxy.cvt.dk/cache/MiamiImageURL/B6THV-44K80TV-FB-1/0?wchp=dGLzVlz-zSkWW X-ray diffraction analysis showed that these phases were amorphous....

  14. DNA nuclease activity of Rev-coupled transition metal chelates.

    Science.gov (United States)

    Joyner, Jeff C; Keuper, Kevin D; Cowan, J A

    2012-06-07

    Artificial nucleases containing Rev-coupled metal chelates based on combinations of the transition metals Fe(2+), Co(2+), Ni(2+), and Cu(2+) and the chelators DOTA, DTPA, EDTA, NTA, tripeptide GGH, and tetrapeptide KGHK have been tested for DNA nuclease activity. Originally designed to target reactive transition metal chelates (M-chelates) to the HIV-1 Rev response element mRNA, attachment to the arginine-rich Rev peptide also increases DNA-binding affinity for the attached M-chelates. Apparent K(D) values ranging from 1.7 to 3.6 µM base pairs for binding of supercoiled pUC19 plasmid DNA by Ni-chelate-Rev complexes were observed, as a result of electrostatic attraction between the positively-charged Rev peptide and negatively-charged DNA. Attachment of M-chelates to the Rev peptide resulted in enhancements of DNA nuclease activity ranging from 1-fold (no enhancement) to at least 13-fold (for Cu-DTPA-Rev), for the rate of DNA nicking, with second order rate constants for conversion of DNA(supercoiled) to DNA(nicked) up to 6 × 10(6) M(-1) min(-1), and for conversion of DNA(nicked) to DNA(linear) up to 1 × 10(5) M(-1) min(-1). Freifelder-Trumbo analysis and the ratios of linearization and nicking rate constants (k(lin)/k(nick)) revealed concerted mechanisms for nicking and subsequent linearization of plasmid DNA for all of the Rev-coupled M-chelates, consistent with higher DNA residency times for the Rev-coupled M-chelates. Observed rates for Rev-coupled M-chelates were less skewed by differing DNA-binding affinities than for M-chelates lacking Rev, as a result of the narrow range of DNA-binding affinities observed, and therefore relationships between DNA nuclease activity and other catalyst properties, such as coordination unsaturation, the ability to consume ascorbic acid and generate diffusible radicals, and the identity of the metal center, are now clearly illustrated in light of the similar DNA-binding affinities of all M-chelate-Rev complexes. This work

  15. Thyroid Antibodies

    Science.gov (United States)

    ... e.g., at regular intervals after thyroid cancer treatment) Thyroid stimulating hormone receptor antibody, Thyroid Stimulating Immunoglobulin TRAb, TSHR Ab, TSI Graves disease When a person has symptoms of hyperthyroidism If a pregnant woman has a known autoimmune ...

  16. Chelation: Harnessing and Enhancing Heavy Metal Detoxification—A Review

    Directory of Open Access Journals (Sweden)

    Margaret E. Sears

    2013-01-01

    Full Text Available Toxic metals such as arsenic, cadmium, lead, and mercury are ubiquitous, have no beneficial role in human homeostasis, and contribute to noncommunicable chronic diseases. While novel drug targets for chronic disease are eagerly sought, potentially helpful agents that aid in detoxification of toxic elements, chelators, have largely been restricted to overt acute poisoning. Chelation, that is multiple coordination bonds between organic molecules and metals, is very common in the body and at the heart of enzymes with a metal cofactor such as copper or zinc. Peptides glutathione and metallothionein chelate both essential and toxic elements as they are sequestered, transported, and excreted. Enhancing natural chelation detoxification pathways, as well as use of pharmaceutical chelators against heavy metals are reviewed. Historical adverse outcomes with chelators, lessons learned in the art of using them, and successes using chelation to ameliorate renal, cardiovascular, and neurological conditions highlight the need for renewed attention to simple, safe, inexpensive interventions that offer potential to stem the tide of debilitating, expensive chronic disease.

  17. Affinity purification of copper chelating peptides from chickpea protein hydrolysates.

    Science.gov (United States)

    Megías, Cristina; Pedroche, Justo; Yust, Maria M; Girón-Calle, Julio; Alaiz, Manuel; Millan, Francisco; Vioque, Javier

    2007-05-16

    Chickpea protein hydrolysates obtained with alcalase and flavourzyme were used for purification of copper chelating peptides by affinity chromatography using copper immobilized on solid supports. The chelating activity of purified peptides was indirectly measured by the inhibition of beta-carotene oxidation in the presence of copper. Two protein hydrolysates, obtained after 10 and 100 min of hydrolysis, were the most inhibitory of beta-carotene oxidation. Purified copper chelating peptides from these protein hydrolysates contained 19.7 and 35.1% histidine, respectively, in comparison to 2.7 and 2.6% in the protein hydrolysates. Chelating peptides from hydrolysate obtained after 10 min of hydrolysis were the most antioxidative being 8.3 times more antioxidative than the hydrolysate, while chelating peptides purified from protein hydrolysate obtained after 100 min were 3.1 times more antioxidative than its hydrolysate. However, the histidine content was higher in peptides derived from the 100 min hydrolysate (19.7 against 35.1% in 10 min hydrolysate), indicating that this amino acid is not the only factor involved in the antioxidative activity, and other factors such as peptide size or amino acid sequence are also determinant. This manuscript shows that affinity chromatography is a useful procedure for purification of copper chelating peptides. This method can be extended to other metals of interest in nutrition, such as calcium, iron, or zinc. Purified chelating peptides, in addition to their antioxidative properties, may also be useful in food mineral fortification for increasing the bioavailability of these metals.

  18. Nanoparticle and other metal chelation therapeutics in Alzheimer disease.

    Science.gov (United States)

    Liu, Gang; Garrett, Matthew R; Men, Ping; Zhu, Xiongwei; Perry, George; Smith, Mark A

    2005-09-25

    Current therapies for Alzheimer disease (AD) such as the anticholinesterase inhibitors and the latest NMDA receptor inhibitor, Namenda, provide moderate symptomatic delay at various stages of disease, but do not arrest disease progression or supply meaningful remission. As such, new approaches to disease management are urgently needed. Although the etiology of AD is largely unknown, oxidative damage mediated by metals is likely a significant contributor since metals such as iron, aluminum, zinc, and copper are dysregulated and/or increased in AD brain tissue and create a pro-oxidative environment. This role of metal ion-induced free radical formation in AD makes chelation therapy an attractive means of dampening the oxidative stress burden in neurons. The chelator desferioxamine, FDA approved for iron overload, has shown some benefit in AD, but like many chelators, it has a host of adverse effects and substantial obstacles for tissue-specific targeting. Other chelators are under development and have shown various strengths and weaknesses. In this review, we propose a novel system of chelation therapy through the use of nanoparticles. Nanoparticles conjugated to chelators show a unique ability to cross the blood-brain barrier (BBB), chelate metals, and exit through the BBB with their corresponding complexed metal ions. This method may prove to be a safe and effective means of reducing the metal load in neural tissue thus staving off the harmful effects of oxidative damage and its sequelae.

  19. Nanoparticle and iron chelators as a potential novel Alzheimer therapy.

    Science.gov (United States)

    Liu, Gang; Men, Ping; Perry, George; Smith, Mark A

    2010-01-01

    Current therapies for Alzheimer disease (AD) such as the acetylcholinesterase inhibitors and the latest NMDA receptor inhibitor, Namenda, provide moderate symptomatic delay at various stages of the disease, but do not arrest the disease progression or bring in meaningful remission. New approaches to the disease management are urgently needed. Although the etiology of AD is largely unknown, oxidative damage mediated by metals is likely a significant contributor since metals such as iron, aluminum, zinc, and copper are dysregulated and/or increased in AD brain tissue and create a pro-oxidative environment. This role of metal ion-induced free radical formation in AD makes chelation therapy an attractive means of dampening the oxidative stress burden in neurons. The chelator desferrioxamine, FDA approved for iron overload, has shown some benefit in AD, but like many chelators, it has a host of adverse effects and substantial obstacles for tissue-specific targeting. Other chelators are under development and have shown various strengths and weaknesses. Here, we propose a novel system of chelation therapy through the use of nanoparticles. Nanoparticles conjugated to chelators show unique ability to cross the blood-brain barrier (BBB), chelate metals, and exit through the BBB with their corresponding complexed metal ions. This method may provide a safer and more effective means of reducing the metal load in neural tissue, thus attenuating the harmful effects of oxidative damage and its sequelae. Experimental procedures are presented in this chapter.

  20. Minimal role of metallothionein in decreased chelator efficacy for cadmium.

    Science.gov (United States)

    Waalkes, M P; Watkins, J B; Klaassen, C D

    1983-05-01

    Chelator efficacy in Cd poisoning drops precipitously if therapy is not commenced almost immediately after exposure. Metallothionein (MT), a low-molecular-weight metal-binding protein with high affinity for Cd, may be important for this phenomenon. To more fully assess this role of MT in the acute drop in chelator efficacy following Cd poisoning, rats were injected iv with radioisotopic Cd (1mg/kg as CdCl2; 50 muCi/kg) followed by diethylenetriaminepentaacetic acid (DTPA; 90 mg/kg ip) at various times (0, 15, 30, 60, and 120 min) after Cd. Ther percentage of the Cd dose remaining in major organs 24 hr following Cd was determined. Although DTPA reduced Cd content in the various organs when given immediately after Cd, the chelator was ineffective at all later times. Increases in hepatic and renal MT did not occur until 2 hr after Cd, and did not coincide with the earlier drop in chelator efficacy. Blockade of MT synthesis by actinomycin D treatment (1.25 mg/kg, 1 hr before Cd) failed to prolong the chelators effectiveness. Furthermore, newborn rats have high levels of hepatic MT which had no effect on the time course of chelator effectiveness since DTPA still decreased Cd organ contents if given immediately following Cd but had no effect if given 2 hr after Cd. Therefore, if appears that MT does not have an important role in the acute decrease in efficacy of chelation therapy for Cd poisoning. The quick onset of chelator ineffectiveness may be due to the rapid uptake of Cd into tissues which makes it relatively unavailable of chelation.

  1. STUDY ON THERMAL DECOMPOSITION KINETICS OF URUSHIOL METAL CHELATE POLYMERS

    Institute of Scientific and Technical Information of China (English)

    HU Binghuan; CHEN Riyao; LIN Jinhuo; CHEN Wending

    1994-01-01

    The thermal decomposition kinetics of urushiol-Cu, urushiol-Nd and urushiol-Ti chelate polymers has been studied by non-isothermal thermogravimetry. The results suggest that the thermal decomposition kinetics of three chelate polymers are all of first order. Their average activation energy values of the thermal decomposition calculated by Ozawa-(Ⅰ) method are 110.79,136.98 and 163.64 kJ mol-1respectively,which increase linearly with the metal valence of the metal chelate polymers

  2. Structure and spectroscopy of uranyl and thorium complexes with substituted phosphine oxide ligands

    Energy Technology Data Exchange (ETDEWEB)

    Breshears, Andrew T.; Barnes, Charles L.; Wagle, Durgesh V.; Baker, Gary A.; Walensky, Justin R. [Missouri Univ., Columbia, MO (United States). Dept. of Chemistry; Takase, Michael K. [California Institute of Technology, Pasadena, CA (United States). Beckman Institute

    2015-05-01

    Phosphine oxide ligands are important in the chemistry of the nuclear fuel cycle. We have synthesized and characterized a series of phosphine oxide ligands with polycyclic aromatic hydrocarbon (PAH) groups to enhance the spectroscopic features of uranyl, UO{sub 2}{sup 2+}, and to make detection more efficient. Complexation of OPPh{sub 2}R, R = C{sub 10}H{sub 7} (naphthyl); C{sub 14}H{sub 9} (phenanthrenyl); C{sub 14}H{sub 9} (anthracenyl); and C{sub 16}H{sub 9} (pyrenyl), to UO{sub 2}(NO{sub 3}){sub 2} afforded the eight-coordinate complexes, UO{sub 2}(NO{sub 3}){sub 2}(OPPh{sub 2}R){sub 2}. An eleven-coordinate complex, Th(NO{sub 3}){sub 4}[OPPh{sub 2}(C{sub 14}H{sub 9})]{sub 3}, C{sub 14}H{sub 9} = phenanthrenyl, was structurally characterized, and was found to be the first thorium compound isolated with three phosphine oxide ligands bound. The phosphine oxide ligands were not fluorescent but the anthracenyl-substituted ligand showed broad, red-shifted emission at approximately 50 nm relative to typical anthracene, making this ligand set a possibility for use in detection. The synthesis and spectroscopy of the uranyl and thorium complexes are presented.

  3. Structural elucidation and physicochemical properties of mononuclear Uranyl(VI) complexes incorporating dianionic units

    Science.gov (United States)

    Azam, Mohammad; Velmurugan, Gunasekaran; Wabaidur, Saikh Mohammad; Trzesowska-Kruszynska, Agata; Kruszynski, Rafal; Al-Resayes, Saud I.; Al-Othman, Zeid A.; Venuvanalingam, Ponnambalam

    2016-01-01

    Two derivatives of organouranyl mononuclear complexes [UO2(L)THF] (1) and [UO2(L)Alc] (2), where L = (2,2′-(1E,1′E)-(2,2-dimethylpropane-1,3-dyl)bis(azanylylidene, THF = Tetrahydrofuran, Alc = Alcohol), have been prepared. These complexes have been determined by elemental analyses, single crystal X-ray crystallography and various spectroscopic studies. Moreover, the structure of these complexes have also been studied by DFT and time dependent DFT measurements showing that both the complexes have distorted pentagonal bipyramidal environment around uranyl ion. TD-DFT results indicate that the complex 1 displays an intense band at 458.7 nm which is mainly associated to the uranyl centered LMCT, where complex 2 shows a band at 461.8 nm that have significant LMCT character. The bonding has been further analyzed by EDA and NBO. The photocatalytic activity of complexes 1 and 2 for the degradation of rhodamine-B (RhB) and methylene blue (MB) under the irradiation of 500W Xe lamp has been explored, and found more efficient in presence of complex 1 than complex 2 for both dyes. In addition, dye adsorption and photoluminescence properties have also been discussed for both complexes. PMID:27595801

  4. Extraction of nitric acid, uranyl nitrate, and bismuth nitrate from aqueous nitric acid solutions with CMPO

    Energy Technology Data Exchange (ETDEWEB)

    Spencer, B.B.

    1995-08-01

    DOE sponsored development of the transuranium extraction (TRUEX) process for removing actinides from radioactive wastes. The solvent is a mixture of CMPO and TBP. Since the extraction characteristics of CMPO are not as well understood as those of TBP, the extraction of nitric acid, uranyl nitrate, and bismuth nitrate with CMPO (dissolved in n-dodecane) were studied. Results indicate that CMPO extracts nitric acid with a 1:1 stoichiometry; equilibrium constant is 2. 660{plus_minus}0.092 at 25 C, and extraction enthalpy is -5. 46{plus_minus}0.46 kcal/mol. Slope analysis indicates that uranyl nitrate extracts with a mixed equilibria of 1:1 and 2:1 stoichiometries in nearly equal proportion. Equil. constant of the 2: 1 extraction was 1.213 {times} 10{sup 6}{plus_minus}3.56 {times} 10{sup 4} at 25 C; reaction enthalpy was -9.610{plus_minus}0.594 kcal/mol. Nitration complexation constant is 8.412{plus_minus}0.579, with an enthalpy of -10.72{plus_minus}1.87 kcal/mol. Bismuth nitrate also extracts with a mixed equilibria of (perhaps) 1:1 and 2:1 stoichiometries. A 2:1 extraction equilibrium and a nitrate complexation adequately model the data. Kinetics and enthalpies were also measured.

  5. Synthesis and Crystal Structure of Bis(nitrate)bis(dipiperidin-1-yl-methanone)uranyl(II)

    Institute of Scientific and Technical Information of China (English)

    朱利明; 何雪雁; 周俊慧; 于正风; 李宝龙; 张勇

    2004-01-01

    The new uranyl complex UO2(NO3)2[C5H10NC(O)NH10C5]2 has been synthesized and its structure was determined by single-crystal X-ray diffraction. Crystal data: C22H40N6O10U, monoclinic, space group P21/c, a = 11.151(3), b = 13.907(3), c = 10.067(2)A,β= 115.602(4)0,V = 1408.0(5) A3, Mr = 786.63, Z = 2, Dc = 1.855 g/cm3, F(000) = 772,μ = 5.827 mm-1, R = 0.0465 and wR = 0.1065 for 2916 observed reflections (I > 2σ(I)). The central uranyl ion is coordinated by six oxygen atoms, of which two are from the carbonyl groups of di-piperidin-1-yl-methanone molecules and the other four from two nitrate groups.

  6. Structural elucidation and physicochemical properties of mononuclear Uranyl(VI) complexes incorporating dianionic units

    Science.gov (United States)

    Azam, Mohammad; Velmurugan, Gunasekaran; Wabaidur, Saikh Mohammad; Trzesowska-Kruszynska, Agata; Kruszynski, Rafal; Al-Resayes, Saud I.; Al-Othman, Zeid A.; Venuvanalingam, Ponnambalam

    2016-09-01

    Two derivatives of organouranyl mononuclear complexes [UO2(L)THF] (1) and [UO2(L)Alc] (2), where L = (2,2‧-(1E,1‧E)-(2,2-dimethylpropane-1,3-dyl)bis(azanylylidene, THF = Tetrahydrofuran, Alc = Alcohol), have been prepared. These complexes have been determined by elemental analyses, single crystal X-ray crystallography and various spectroscopic studies. Moreover, the structure of these complexes have also been studied by DFT and time dependent DFT measurements showing that both the complexes have distorted pentagonal bipyramidal environment around uranyl ion. TD-DFT results indicate that the complex 1 displays an intense band at 458.7 nm which is mainly associated to the uranyl centered LMCT, where complex 2 shows a band at 461.8 nm that have significant LMCT character. The bonding has been further analyzed by EDA and NBO. The photocatalytic activity of complexes 1 and 2 for the degradation of rhodamine-B (RhB) and methylene blue (MB) under the irradiation of 500W Xe lamp has been explored, and found more efficient in presence of complex 1 than complex 2 for both dyes. In addition, dye adsorption and photoluminescence properties have also been discussed for both complexes.

  7. Synthesis and structure determination of uranyl peroxide nanospheres in the presence of organic structure directing agents

    Science.gov (United States)

    Forbes, T. Z.; Burns, P. C.

    2007-12-01

    Recently, actinyl peroxide nanoclusters containing 20, 24, 28, or 32 actinyl polyhedra have been synthesized and their structures identified with single crystal X-ray diffraction [1]. Most nanomaterials are composed of main group elements or transition metals, therefore, these actinyl nanospheres may display vastly different chemical and physical properties due to the presence of filled f-orbitals. A major goal of our research group is to create novel actinyl materials, focusing on nano- and mesoporous materials. The original nanosphere syntheses were limited to inorganic crystallization agents, such as monovalent cations. Over the last decade, the use of organic compounds and surfactants have received increased attention as structure-directing agents for the generation of novel inorganic materials. Using structure-directing organic amines we have successfully synthesized and determined the structures of uranyl nanospheres containing 40 and 50 uranyl polyhedra. The topology of the skeletal U-50 nanosphere is identical to the C50Cl10 fullerene [2]. The topographical relationship between the actinyl nanospheres and fullerene or fullerene-like material may provide additional insight into stable configurations for lower fullerenes. [1] Burns et al., Actinyl peroxide nanospheres. Angewandte Chemie, International Edition, 2005. 44(14): p. 2135. [2] Xie et al., Capturing the Labile Fullerene[50] as C50Cl10. Science, (2004) 305(5671): p. 699.

  8. Rapid dissolution of soluble uranyl phases in arid, mine-impacted catchments near Church Rock, NM.

    Science.gov (United States)

    deLemos, Jamie L; Bostick, Benjamin C; Quicksall, Andrew N; Landis, Joshua D; George, Christine C; Slagowski, Naomi L; Rock, Tommy; Brugge, Doug; Lewis, Johnnye; Durant, John L

    2008-06-01

    We tested the hypothesis that runoff of uranium-bearing particles from mining waste disposal areas was a significant mechanism for redistribution of uranium in the northeastern part of the Upper Puerco River watershed (New Mexico). However, our results were not consistent with this hypothesis. Analysis of > 100 sediment and suspended sediment samples collected adjacent to and downstream from uranium source areas indicated that uranium levels in the majority of the samples were not elevated above background. Samples collected within 50 m of a known waste disposal site were subjected to detailed geochemical characterization. Uranium in these samples was found to be highly soluble; treatment with synthetic pore water for 24 h caused dissolution of 10--50% of total uranium in the samples. Equilibrium uranium concentrations in pore water were > 4.0 mg/L and were sustained in repeated wetting events, effectively depleting soluble uranium from the solid phase. The dissolution rate of uranium appeared to be controlled by solid-phase diffusion of uranium from within uranium-bearing mineral particles. X-ray adsorption spectroscopy indicated the presence of a soluble uranyl silicate, and possibly a uranyl phosphate. These phases were exhausted in transported sediment suggesting that uranium was readily mobilized from sediments in the Upper Puerco watershed and transported in the dissolved load. These results could have significance for uranium risk assessment as well as mining waste management and cleanup efforts.

  9. Alternative process to produce UF{sub 4} using the effluent from ammonium uranyl carbonate route

    Energy Technology Data Exchange (ETDEWEB)

    Silva Neto, Joao B.; Garcia, Rafael Henrique Lazzari; Dal Vechio, Edvaldo, E-mail: jbsneto@ipen.br [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), SP (Brazil); Riella, Humberto G., E-mail: riella@enq.ufsc.br [Universidade Federal de Santa Catarina (UFSC), Florianopolis, SC (Brazil); Instituto Nacional de Ciencias e Tecnologia de Reatores Nucleares Inovadores (INCT/CNPq) (Brazil); Carvalho, Elita F. Urano de; Durazzo, Michelangelo [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), SP (Brazil); Instituto Nacional de Ciencias e Tecnologia de Reatores Nucleares Inovadores (INCT/CNPq) (Brazil)

    2011-07-01

    The Nuclear Fuel Centre of IPEN / CNEN - SP develops and manufactures dispersion fuel with high uranium concentration. It meets the demand of the IEA-R1 reactor and future research reactors to be constructed in Brazil. The fuel uses uranium silicide (U{sub 3}Si{sub 2}) dispersed in aluminum. For producing the fuel, the process of uranium hexafluoride (UF{sub 6}) conversion consist in obtaining U{sub 3}Si{sub 2} and / or U{sub 3}O{sub 8} through the preparation of intermediate compounds, among them ammonium uranyl carbonate - AUC, ammonium diuranate - DUA and uranium tetrafluoride - UF{sub 4}. This work describes a procedure for preparing uranium tetrafluoride via a dry route, using as raw material the filtrate generated when ammonium uranyl carbonate is routinely produced. The filtrate consists mainly of a solution containing high concentrations of ammonium (NH{sup 4+}), fluoride (F{sup -}), carbonate (CO{sup 3-}) and low concentrations of uranium. The procedure consists in recovering NH{sup 4F} and uranium, as UF{sub 4}, through the crystallization of ammonium bifluoride (NH{sub 4}HF{sub 2}) and, in a later step, the addition of UO{sub 2}, occurring fluoridation and decomposition. The UF{sub 4} obtained is further diluted in the UF{sub 4} produced routinely at IPEN / CNEN-SP by a wet route process. (author)

  10. Isotope selectivity of infrared laser-driven unimolecular dissociation of a volatile uranyl compound.

    Science.gov (United States)

    Cox, D M; Hall, R B; Horsley, J A; Kramer, G M; Rabinowitz, P; Kaldor, A

    1979-07-27

    Isotope-selective photodissociation of the volatile complex uranyl hexafluoroacetylacetonate . tetrahydrofuran [UO(2)(hfacac)(2) . THF] has been achieved with both a continuous-wave and a pulsed carbon dioxide laser. The photodissociation was carried out in a low-density molecular beam under collisionless conditions. Transitions of the laser are in resonance with the asymmetric O-U-O stretch of the uranyl moiety, a vibrational mode whose frequency is sensitive to the masses of the uranium and oxygen isotopes. Unimolecular dissociation is observed mass spectrometrically at an extremely low energy fluence, with no evidence of an energy fluence or intensity threshold. The dissociation yield increases nearly linearly with increasing energy fluence. At constant fluence the dissociation yield is independent of contact time between the radiation field and the molecule, indicating that the decomposition is driven by laser energy fluence and not laser intensity. The oxygen and uranium isotope selectivities measured in these experiments are nearly those predicted by the ratio of the linear absorption cross sections for the respective isotopes. Thus, essentially complete selectivity is observed for oxygen isotopes, while a selectivity of only about 1.25 is measured for the uranium isotopes. A model presented to describe these results is based on rapid intramolecular vibrational energy flow from the pumped mode into a limited number of closely coupled modes.

  11. A New Form of Triple-Stranded Helicate Found in Uranyl Complexes of Aliphatic α,ω-Dicarboxylates.

    Science.gov (United States)

    Thuéry, Pierre; Harrowfield, Jack

    2015-11-16

    The reaction of uranyl ions with azelaic or dodecanedioic acids under solvohydrothermal conditions leads to crystallization of anionic dinuclear cage compounds with [M(bipy/phen)3](2+) counterions (M = 3d-block cation), while the smaller suberic acid yields heterometallic metallacycles. Complexes with the longer aliphatic chains are the first triple-stranded helicates reported in actinide chemistry.

  12. Treatment of uranyl nitrate and flouride solutions; Tratamiento de soluciones que contienen nitrato de uranilo y fluoruros

    Energy Technology Data Exchange (ETDEWEB)

    Rodrigo Otero, A.; Rodrigo Vilaseca, F.; Morales Calvo, G.

    1977-07-01

    A theoretical study on the fluoride complexes contained in uranyl and aluminium solutions has been carried out. Likewise concentration limits and Duhring diagrams for those solutions have been experimentally established. As a result, the optimum operation conditions for concentration by evaporation in the treatment plant, have been deduced. (Author) 12 refs.

  13. Synthesis of thermally stable extra-large pore crystalline materials: a uranyl germanate with 12-ring channels.

    Science.gov (United States)

    Lin, Chia-Hui; Chiang, Ray-Kuang; Lii, Kwang-Hwa

    2009-02-18

    A thermally stable extra-large pore uranyl germanate is synthesized under high-temperature, high-pressure hydrothermal conditions at 585 degrees C and 150 MPa. The structure contains U(6+)O(6) tetragonal bipyramids which are interconnected by digermanate groups to form a 3D framework with 12-ring pore openings.

  14. Isotherm And Kinetic Studies On The Electrosorption Of Uranyl Tricarbonate Complex [UO{sub 2}(CO{sub 3}){sub 3}]{sup 4-} From Aqueous Solutions By Activated Carbon Electrodes

    Energy Technology Data Exchange (ETDEWEB)

    Ismail, Aznan Fazli; Yim, Man Sung [Korea Advanced Institute of Science and Technology, Daejeon (Korea, Republic of)

    2015-05-15

    Many types of adsorbent materials have been developed over the past 50 years, and the most recognizable is amidoxime based materials which is known to have high affinity in in chelating uranyl ions from seawater. However, the fabrication cost of amidoxime based materials was high which lead to high uranium extraction cost. In recent studies, use of porous carbon materials combined with the electrosorption technique was shown to have high selectivity for uranium separation from seawater. It is clear that the electrosorption capacity increase with the increasing of electrolyte concentration. The investigated activated carbon electrode still not reach the maximum adsorption capacity in the test condition. The morphology analysis confirmed that the fabricated activated carbon electrode has a porous structure, where BET analysis has revealed that the size of the pores can be categorized in mesopores region which is the optimum condition for electrosorption purposes. Other than that, the FT-IR analysis has enough evident that the molecular interaction of the activated carbon electrode involves the intermolecular interaction (physical crosslink/bonding) and stable for electrosorption application.

  15. Synthetic Lubricating Oil Greases Containing Metal Chelates of Schiff Bases

    Science.gov (United States)

    1992-09-15

    greases comprising the addition to said greases of effective amounts of a chelated Schiff base derived from the condensation of approximately stoichiometic amounts of at least one aldehyde and a polyamine.

  16. Comparing potential copper chelation mechanisms in Parkinson's disease protein

    Science.gov (United States)

    Rose, Frisco; Hodak, Miroslav; Bernholc, Jerry

    2011-03-01

    We have implemented the nudged elastic band (NEB) as a guided dynamics framework for our real-space multigrid method of DFT-based quantum simulations. This highly parallel approach resolves a minimum energy pathway (MEP) on the energy hypersurface by relaxing intermediates in a chain-of-states. As an initial application we present an investigation of chelating agents acting on copper ion bound to α -synuclein, whose misfolding is implicated in Parkinson's disease (PD). Copper ions are known to act as highly effective misfolding agents in a-synuclein and are thus an important target in understanding PD. Furthermore, chelation therapy has shown promise in the treatment of Alzheimer's and other neuro-degenerative diseases with similar metal-correlated pathologies. At present, our candidate chelating agents include nicotine, curcumin and clioquinol. We examine their MEP activation barriers in the context of a PD onset mechanism to assess the viability of various chelators for PD remediation.

  17. Development of Multi-Functional Chelators Based on Sarcophagine Cages

    Directory of Open Access Journals (Sweden)

    Shuanglong Liu

    2014-04-01

    Full Text Available A new class of multifunctionalized sarcophagine derivatives was synthesized for 64Cu chelation. The platform developed in this study could have broad applications in 64Cu-radiopharmaceuticals.

  18. Metal chelate process to remove pollutants from fluids

    Science.gov (United States)

    Chang, Shih-Ger T.

    1994-01-01

    The present invention relates to improved methods using an organic iron chelate to remove pollutants from fluids, such as flue gas. Specifically, the present invention relates to a process to remove NO.sub.x and optionally SO.sub.2 from a fluid using a metal ion (Fe.sup.2+) chelate wherein the ligand is a dimercapto compound wherein the --SH groups are attached to adjacent carbon atoms (HS--C--C--SH) or (SH--C--CCSH) and contain a polar functional group so that the ligand of DMC chelate is water soluble. Alternatively, the DMC' is covalently attached to a water insoluble substrate such as a polymer or resin, e.g., polystyrene. The chelate is regenerated using electroreduction or a chemical additive. The dimercapto compound bonded to a water insoluble substrate is also useful to lower the concentration or remove hazardous metal ions from an aqueous solution.

  19. A Brief Review of Chelators for Radiolabeling Oligomers

    Directory of Open Access Journals (Sweden)

    Yuxia Liu

    2010-05-01

    Full Text Available The chemical modification of oligomers such as DNA, PNA, MORF, LNA to attach radionuclides for nuclear imaging and radiotherapy applications has become a field rich in innovation as older methods are improved and new methods are introduced. This review intends to provide a brief overview of several chelators currently in use for the labeling of oligomers with metallic radionuclides such as 99mTc, 111In and 188Re. While DNA and its analogs have been radiolabeled with important radionuclides of nonmetals such as 32P, 35S, 14C, 18F and 125I, the labeling methods for these isotopes involve covalent chemistry that is quite distinct from the coordinate-covalent chelation chemistry described herein. In this review, we provide a summary of the several chelators that have been covalently conjugated to oligomers for the purpose of radiolabeling with metallic radionuclides by chelation and including details on the conjugation, the choice of radionuclides and labeling methods.

  20. Metal chelate process to remove pollutants from fluids

    Science.gov (United States)

    Chang, S.G.T.

    1994-12-06

    The present invention relates to improved methods using an organic iron chelate to remove pollutants from fluids, such as flue gas. Specifically, the present invention relates to a process to remove NO[sub x] and optionally SO[sub 2] from a fluid using a metal ion (Fe[sup 2+]) chelate wherein the ligand is a dimercapto compound wherein the --SH groups are attached to adjacent carbon atoms (HS--C--C--SH) or (SH--C--CCSH) and contain a polar functional group so that the ligand of DMC chelate is water soluble. Alternatively, the DMC is covalently attached to a water insoluble substrate such as a polymer or resin, e.g., polystyrene. The chelate is regenerated using electroreduction or a chemical additive. The dimercapto compound bonded to a water insoluble substrate is also useful to lower the concentration or remove hazardous metal ions from an aqueous solution. 26 figures.

  1. A novel assay for monitoring internalization of nanocarrier coupled antibodies

    Directory of Open Access Journals (Sweden)

    Pickering Edward M

    2006-10-01

    Full Text Available Abstract Background Discovery of tumor-selective antibodies or antibody fragments is a promising approach for delivering therapeutic agents to antigen over-expressing cancers. Therefore it is important to develop methods for the identification of target- and function specific antibodies for effective drug delivery. Here we describe a highly selective and sensitive method for characterizing the internalizing potential of multivalently displayed antibodies or ligands conjugated to liposomes into tumor cells. The assay requires minute amounts of histidine-tagged ligand and relies on the non-covalent coupling of these antibodies to fluorescent liposomes containing a metal ion-chelating lipid. Following incubation of cells with antibody-conjugated liposomes, surface bound liposomes are gently removed and the remaining internalized liposomes are quantitated based on fluorescence in a high throughput manner. We have termed this methodology "Chelated Ligand Internalization Assay", or CLIA. Results The specificity of the assay was demonstrated with different antibodies to the ErbB-2 and EGF receptors. Antibody-uptake correlated with receptor expression levels in tumor cell lines with a range of receptor expression. Furthermore, Ni-NTA liposomes containing doxorubicin were used to screen for the ability of antibodies to confer target-specific cytotoxicity. Using an anti-ErbB2 single chain Fv (scFv (F5 antibody, cytotoxicity could be conferred to ErbB2-overexpressing cells; however, a poly(ethylene glycol-linked lipid (DSPE-PEG-NTA-Ni was necessary to allow for efficient loading of the drug and to reduce nonspecific drug leakage during the course of the assay. Conclusion The CLIA method we describe here represents a rapid, sensitive and robust assay for the identification and characterization of tumor-specific antibodies capable of high drug-delivery efficiency when conjugated to liposomal nanocarriers.

  2. Chelated Ruthenium Catalysts for Z-Selective Olefin Metathesis

    Science.gov (United States)

    Endo, Koji; Grubbs, Robert H.

    2011-01-01

    We report the development of ruthenium-based metathesis catalysts with chelating N-heterocyclic carbene (NHC) ligands which catalyze highly Z-selective olefin metathesis. A very simple and convenient synthetic procedure of such a catalyst has been developed. An intramolecular C-H bond activation of the NHC ligand, which is promoted by anion ligand substitution, forms the appropriate chelate for stereo- controlled olefin metathesis. PMID:21563826

  3. Iron Chelation Adherence to Deferoxamine and Deferasirox in Thalassemia

    OpenAIRE

    Trachtenberg, Felicia; Vichinsky, Elliott; Haines, Dru; Pakbaz, Zahra; Mednick, Lauren; Sobota, Amy; Kwiatkowski, Janet; Thompson, Alexis A.; Porter, John; Coates, Thomas; Giardina, Patricia J.; Olivieri, Nancy; Yamashita, Robert; Neufeld, Ellis J.

    2011-01-01

    The Thalassemia Clinical Research Network collected adherence information from 79 patients on deferoxamine and 186 on deferasirox from 2007 to 2009. Chelation adherence was defined as percent of doses administered in the last 4 weeks (patient report) out of those prescribed (chart review). Chelation history since 2002 was available for 97 patients currently on deferoxamine and 217 on deferasirox, with crude estimates of adherence from chart review. Self-reported adherence to both deferoxamine...

  4. Deferasirox, an oral chelator in the treatment of iron overload

    OpenAIRE

    I. Portioli

    2013-01-01

    BACKGROUND Deferasirox is a once-daily oral iron chelator developed for treating iron overload complicating long-term transfusion therapy in patients with diseases such as beta-thalassemia and myelodysplastic syndromes. Iron overload can damage the liver, pancreas and the heart. Deferoxamine, the only other drug approved for iron chelation, can prevent these effects but requires parenteral administration. Deferasirox has been approved after a one-year, open-label trial in patients ≥ 2 years o...

  5. Iron-chelating agent, deferasirox, inhibits neutrophil activation and extracellular trap formation.

    Science.gov (United States)

    Kono, Mari; Saigo, Katsuyasu; Yamamoto, Shiori; Shirai, Kohei; Iwamoto, Shuta; Uematsu, Tomoko; Takahashi, Takayuki; Imoto, Shion; Hashimoto, Makoto; Minami, Yosuke; Wada, Atsushi; Takenokuchi, Mariko; Kawano, Seiji

    2016-10-01

    Iron-chelating agents, which are frequently prescribed to transfusion-dependent patients, have various useful biological effects in addition to chelation. Reactive oxygen species (ROS) produced by neutrophils can cause pulmonary endothelial cell damage, which can lead to acute lung injury (ALI). We previously reported that deferasirox (DFS), an iron-chelating agent, inhibits phorbol myristate acetate (PMA) or formyl-methionyl-leucyl-phenylalanine (fMLP)-induced ROS production in neutrophils, in vitro. Here, we investigate whether DFS inhibits vacuolization in neutrophils and neutrophil extracellular trap (NET) formation. Human neutrophils were incubated with DFS and stimulated with PMA or fMLP. Human neutrophils were separated from heparinized peripheral blood using density gradient centrifugation, and subsequently incubated with DFS. After 10 minutes, neutrophils were stimulated by PMA or fMLP. Vacuole formation was observed by electron microscopy. For observing NET formations using microscopes, immunohistological analyses using citrullinated histone H3 and myeloperoxidase antibodies, and SYTOX Green (an impermeable DNA detection dye) staining, were conducted. NET formation was measured as the quantity of double-stranded DNA (dsDNA), using the AccuBlue Broad Range dsDNA Quantitation Kit. DFS (50 μmol/L) inhibited vacuole formation in the cytoplasm and NET formation. Additionally, 5-100 μmol/L concentration of DFS inhibited the release of dsDNA in a dose-independent manner. We demonstrate that DFS inhibits not only ROS production but also vacuolization and NET formation in neutrophils. These results suggest the possibility of protective effects of DFS against NET-related adverse effects, including ALI and thrombosis.

  6. Μethods of iron chelation therapy: a bibliographic review

    Directory of Open Access Journals (Sweden)

    Maria Agapiou

    2012-01-01

    Full Text Available "Iron Chelation Therapy" is a term used to describe the procedure of removing excess iron from the body, which is applied after a total of approximately 20 blood transfusions or when serum ferritin levels rise above 1000 ng/ml. Aim: The purpose of the present paper is a retrospective search in bibliography, concerning the methods of iron chelation treatment for patients with hemochromatosis owing to their undergoing multiple blood transfusions. Method: The methology followed, included the search for review and research studies, in electronic databases as well as scientific haematology journals, mostly regarding recent entries in greek and international bibliography. Results: According to the bibliography, chelation therapy compounds have significantly changed the patients' clinical features and have substantially improved their quality of life, along with their outcome over time. However, the level of patient compliance to treatment still remains the basic problem of iron chelation therapy. Conclusions: Even though the discovery of orally administered chelating agents can qualify as an auspicious accomplishment, research fields should cover a much wider spectrum, in order to improve the effectiveness of iron chelation treatment.

  7. Iron Chelation Adherence to Deferoxamine and Deferasirox in Thalassemia

    Science.gov (United States)

    Trachtenberg, Felicia; Vichinsky, Elliott; Haines, Dru; Pakbaz, Zahra; Mednick, Lauren; Sobota, Amy; Kwiatkowski, Janet; Thompson, Alexis A.; Porter, John; Coates, Thomas; Giardina, Patricia J.; Olivieri, Nancy; Yamashita, Robert; Neufeld, Ellis J.

    2015-01-01

    The Thalassemia Clinical Research Network collected adherence information from 79 patients on deferoxamine and 186 on deferasirox from 2007 to 2009. Chelation adherence was defined as percent of doses administered in the last 4 weeks (patient report) out of those prescribed (chart review). Chelation history since 2002 was available for 97 patients currently on deferoxamine and 217 on deferasirox, with crude estimates of adherence from chart review. Self-reported adherence to both deferoxamine and deferasirox were quite high, with slightly higher adherence to the oral chelator (97 vs. 92%). Ninety percent of patients on deferasirox reported at least 90% adherence, compared with 75% of patients on deferoxamine. Adherence to both chelators was highest in children, followed by adolescents and older adults. Predictors of lower deferoxamine adherence were smoking in the past year, problems sticking themselves (adults only), problems wearing their pump, and fewer transfusions in the past year. Predictors of lower deferasirox adherence were bodily pain and depression. Switching chelators resulted in increased adherence, regardless of the direction of the switch, although switching from deferoxamine to deferasirox was far more common. As adherence to deferoxamine is higher than previously reported, it appears beneficial for patients to have a choice in chelators. PMID:21523808

  8. Extraction of metals using supercritical fluid and chelate forming legand

    Science.gov (United States)

    Wai, Chien M.; Laintz, Kenneth E.

    1998-01-01

    A method of extracting metalloid and metal species from a solid or liquid material by exposing the material to a supercritical fluid solvent containing a chelating agent is described. The chelating agent forms chelates that are soluble in the supercritical fluid to allow removal of the species from the material. In preferred embodiments, the extraction solvent is supercritical carbon dioxide and the chelating agent is a fluorinated .beta.-diketone. In especially preferred embodiments the extraction solvent is supercritical carbon dioxide, and the chelating agent comprises a fluorinated .beta.-diketone and a trialkyl phosphate, or a fluorinated .beta.-diketone and a trialkylphosphine oxide. Although a trialkyl phosphate can extract lanthanides and actinides from acidic solutions, a binary mixture comprising a fluorinated .beta.-diketone and a trialkyl phosphate or a trialkylphosphine oxide tends to enhance the extraction efficiencies for actinides and lanthanides. The method provides an environmentally benign process for removing contaminants from industrial waste without using acids or biologically harmful solvents. The method is particularly useful for extracting actinides and lanthanides from acidic solutions. The chelate and supercritical fluid can be regenerated, and the contaminant species recovered, to provide an economic, efficient process.

  9. Extraction of metals using supercritical fluid and chelate forming ligand

    Science.gov (United States)

    Wai, C.M.; Laintz, K.E.

    1998-03-24

    A method of extracting metalloid and metal species from a solid or liquid material by exposing the material to a supercritical fluid solvent containing a chelating agent is described. The chelating agent forms chelates that are soluble in the supercritical fluid to allow removal of the species from the material. In preferred embodiments, the extraction solvent is supercritical carbon dioxide and the chelating agent is a fluorinated {beta}-diketone. In especially preferred embodiments the extraction solvent is supercritical carbon dioxide, and the chelating agent comprises a fluorinated {beta}-diketone and a trialkyl phosphate, or a fluorinated {beta}-diketone and a trialkylphosphine oxide. Although a trialkyl phosphate can extract lanthanides and actinides from acidic solutions, a binary mixture comprising a fluorinated {beta}-diketone and a trialkyl phosphate or a trialkylphosphine oxide tends to enhance the extraction efficiencies for actinides and lanthanides. The method provides an environmentally benign process for removing contaminants from industrial waste without using acids or biologically harmful solvents. The method is particularly useful for extracting actinides and lanthanides from acidic solutions. The chelate and supercritical fluid can be regenerated, and the contaminant species recovered, to provide an economic, efficient process. 7 figs.

  10. Iron chelation adherence to deferoxamine and deferasirox in thalassemia.

    Science.gov (United States)

    Trachtenberg, Felicia; Vichinsky, Elliott; Haines, Dru; Pakbaz, Zahra; Mednick, Lauren; Sobota, Amy; Kwiatkowski, Janet; Thompson, Alexis A; Porter, John; Coates, Thomas; Giardina, Patricia J; Olivieri, Nancy; Yamashita, Robert; Neufeld, Ellis J

    2011-05-01

    The Thalassemia Clinical Research Network collected adherence information from 79 patients on deferoxamine and 186 on deferasirox from 2007 to 2009. Chelation adherence was defined as percent of doses administered in the last 4 weeks (patient report) out of those prescribed(chart review). Chelation history since 2002 was available for 97 patients currently on deferoxamine and 217 on deferasirox, with crude estimates of adherence from chart review. Self-reported adherence to both deferoxamine and deferasirox were quite high, with slightly higher adherence to the oral chelator (97 vs. 92%). Ninety percent of patients on deferasirox reported at least 90% adherence, compared with 75% of patients on deferoxamine. Adherence to both chelators was highest in children, followed by adolescents and older adults.Predictors of lower deferoxamine adherence were smoking in the past year, problems sticking themselves (adults only), problems wearing their pump, and fewer transfusions in the past year. Predictors of lower deferasirox adherence were bodily pain and depression. Switching chelators resulted in increased adherence, regardless of the direction of the switch, although switching from deferoxamine to deferasirox was far more common. As adherence to deferoxamine is higher than previously reported, it appears beneficial for patients to have a choice in chelators.

  11. Eu-Chelate Construct Ultrasensitive Time-Resolved Fluoroimmunoassay-Assay of Pepsinogen I

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    Eu-chelate were used to construct a two-site sandwich-type assay for pepsinogen I (PGI) with time-resolved fluoroimmunoassay (TRFIA) as a detection technique. On the noncompetitive assay, captured monoclonal antibodies (McAbs) coated on wells were directed against a specific antigenic site on the PGI. Another McAbs, called as labeling McAbs, were prepared with the Eu-chelate of N-(p-isothiocyanatobenzyl)-diethylenetriamine-N, N, N, N-tetraacetic acid and directed against a different antigenic site on the PGI. The fluorescence counts of bound Eu3 +-McAbs were measured with the auto DELFIA1235 system. The PGI in sera from healthy volunteers were determined by PGI-TRFIA. The within-run and between-run CVs of the PGI-TRFIA were 1.9% and 4.7%, respectively, and the recovery rate was 102.65%. The cross-reacting rate with pepsinogen Ⅱ was negligible. The linear correlation of PGI-TRFIA and radioimmunassay measurePGI. The availability of a highly sensitive, reliable, and convenient method for quantifying PGI will allow investigations into the possible diagnostic value of this analyte in various clinical conditions, including gastric carcinoma, duodenal ulcer, gastritis and severe atrophic gastritis.

  12. Site-specific conjugation of bifunctional chelator BAT to mouse IgG1 Fab' fragment

    Institute of Scientific and Technical Information of China (English)

    Jun LI; Xue-hao WANG; Xiao-ming WANG; Zhao-lai CHEN

    2006-01-01

    Aim: To perform a site-specific conjugation of Fab' fragments of a mouse monoclonal antibody(MoAb) B43(of IgG1 subtype) to a bifunctional chelator 6-[p-(bromoacetamido) benzyl]-l,4,8,11-tetraazacyclotetradecane-N,N',N",N'"-tetraacetic acid (BAT) via the thiol groups in the hinge distal to the antigenbinding site of the Fab'. Methods: B43 was cleaved using a simple 2-step method.First, stable F(ab')2 was produced by pepsin treatment. Fab' with free thiol in the hinge region was then obtained by cysteine reduction of F(ab')2. Second, a sitespecific conjugation of Fab' to thiol-specific BAT was performed in a one-step reaction. Results: The Fab' fragment had approximately 1.8 free thiol groups per molecule after cysteine reduction. The conjugation efficiency and the chemical yield were approximately 1.28 moles chelator/Fab' and 74% of the initial concentration of Fab', respectively. The F(ab')2, Fab' and Fab'-BAT all maintained reasonable antigen-binding properties. 67Cu labeling of the conjugate under standard conditions did not impair the immunoreactivity of Fab'-BAT. Conclusion: This is a simple and efficient method for producing immunoreactive conjugates of Fab'-BAT, which can be used to make radiometal-labeled conjugates for further diagnostic and therapeutic applications.

  13. Field-Portable Immunoassay Instruments and Reagents to Measure Chelators and Mobile Forms of Uranium

    Energy Technology Data Exchange (ETDEWEB)

    Blake, Diane A.

    2006-01-23

    Progress Report Date: 01/23/06 (report delayed due to Hurricane Katrina) Report of results to date: The goals of this 3-year project are to: (1) update and successfully deploy our present immunosensors at DOE sites; (2) devise immunosensor-based assays for Pb(II), Hg(II), chelators, and/or Cr(III) in surface and groundwater; and (3) develop new technologies in antibody engineering that will enhance this immunosensor program. Note: Work on this project was temporarily disrupted when Hurricane Katrina shut down the University on August 29, 2005. While most of the reagents stored in our refrigerators and freezers were destroyed, all of our hybridoma cell lines were saved because they had been stored in liquid nitrogen. We set up new tissue culture reactors with the hybridomas that synthesize the anti-uranium antibodies, and are purifying new monoclonal antibodies from these culture supernatants. Both the in-line and the field-portable sensor were rescued from our labs in New Orleans in early October, and we continued experiments with these sensors in the temporary laboratory we set up in Hammond, LA at Southeastern Louisiana University.

  14. THE STUDIES ON CHELATING FIBER V.ADSORPTION BEHAVIOR OF Au3+ ONTO CHELATING FIBER CONTAINING AMIDOXIME GROUPS

    Institute of Scientific and Technical Information of China (English)

    LINWeiping; LUYun; 等

    1992-01-01

    The adsorption behavior of ionic gold onto chelating fiber containing amidoxime groups was investigated. The chelating fiber presents high adsorption capacity for ionic gold Au3+(up to 626mg/g,when the content of amidoxime group reaches 7.59mmol/g),and possesses the ability to reduce the Au3+ into metallic gold,In the redox process,the amidoxime group is oxidized into carboxyl group.

  15. Analysis of uranyl in solution through the formation of luminescent complexes; Analisis de uranilo en solucion mediante la formacion de complejos luminiscentes

    Energy Technology Data Exchange (ETDEWEB)

    Garcia G, N.; Ordonez R, E.; Barrera D, C.E. [ININ, 52750 La Marquesa, Estado de Mexico (Mexico)

    2008-07-01

    The luminescence is one of the techniques used to determine the speciation of those complex that forms the uranyl in the solid-liquid interphase of distinct zirconium phosphates, also has the advantage that it allows to carry out its quantification at mid of high ion forces, because it has been demonstrated that this detection technique and quantification is reliable and sufficiently quick in the obtaining of results. For it that in this work, the quantification of the uranyl is presented by means of a luminescent complex with the aim of phosphates that avoid the fluorescence signal extinction, then the uranyl ion is very sensitive to the medium that contains it (pH, ion force, concentration, etc.) for what was necessary to establish the analysis conditions of the uranyl ion without signal lost, in inferior concentrations to 1X10{sup -3} M at mid of sodium perchlorate 0.5 M. (Author)

  16. Cage-like bifunctional chelators, copper-64 radiopharmaceuticals and PET imaging using the same

    Energy Technology Data Exchange (ETDEWEB)

    Conti, Peter S.; Cai, Hancheng; Li, Zibo; Liu, Shuanglong

    2016-08-02

    Disclosed is a class of versatile Sarcophagine based bifunctional chelators (BFCs) containing a hexa-aza cage for labeling with metals having either imaging, therapeutic or contrast applications radiolabeling and one or more linkers (A) and (B). The compounds have the general formula ##STR00001## where A is a functional group selected from group consisting of an amine, a carboxylic acid, an ester, a carbonyl, a thiol, an azide and an alkene, and B is a functional group selected from the group consisting of hydrogen, an amine, a carboxylic acid, and ester, a carbonyl, a thiol, an azide and an alkene. Also disclosed are conjugate of the BFC and a targeting moiety, which may be a peptide or antibody. Also disclosed are metal complexes of the BFC/targeting moiety conjugates that are useful as radiopharmaceuticals, imaging agents or contrast agents.

  17. MCNP-DSP calculations of measurements with uranyl nitrate solution system

    Energy Technology Data Exchange (ETDEWEB)

    Valentine, T.E. [Oak Ridge National Lab., TN (United States)

    1998-09-01

    The {sup 252}Cf-source-driven noise analysis method has been used to determine the subcriticality of various configurations of fissile materials. In the past, the application of this method was limited because point-kinetics models had to be used to interpret the data; however, with the development of the Monte Carlo code MCNP-DSP, the measurements can be analyzed using the more general Monte Carlo models. The results of the Monte carlo calculations will be dependent on the ability to model the experiment accurately and on the nuclear data used to perform the calculations. This paper presents a comparison of the measured and calculated ratio of spectral densities for a subset of measurements performed with a uranyl nitrate solution tank filled to various heights. The results presented are for calculations that were performed with both ENDF/B-IV and ENDF/B-V cross-section data sets.

  18. REGIONAL SIDEROSIS: A NEW CHALLENGE FOR IRON CHELATION THERAPY

    Directory of Open Access Journals (Sweden)

    Zvi Ioav Cabantchik

    2013-12-01

    Full Text Available The traditional role of iron chelation therapy has been to reduce body iron burden via chelation of excess metal from organs and fluids and its excretion via biliary-fecal and/or urinary routes. In their present use for hemosiderosis, chelation regimens might not be suitable for treating disorders of iron maldistribution, as those are characterized by toxic islands of siderosis appearing in a background of normal or subnormal iron levels (e.g. sideroblastic anemias, neuro- and cardio-siderosis in Friedreich ataxia- and neurosiderosis in Parkinson’s disease. We aimed at clearing local siderosis from aberrant labile metal that promotes oxidative damage, without interfering with essential local functions or with hematological iron-associated properties. For this purpose we introduced a conservative mode of iron chelation based on dual activity based on scavenging labile metal but also redeploying it to cell acceptors or to physiological transferrin. The scavenging and redeployment mode of action was designed both for correcting aberrant iron distribution and also for minimizing/preventing systemic loss of chelated metal. We first examine cell models that recapitulate iron maldistribution and associated dysfunctions identified with Friedreich ataxia and Parkinson’s disease and use them to explore the ability of the double-acting agent deferiprone, an orally active chelator, to mediate iron scavenging and redeployment and thereby causing functional improvement. We subsequently evaluate the concept in translational models of disease and finally assess its therapeutic potential in prospective double-blind pilot clinical trials. We claim that any chelator applied to diseases of regional siderosis, cardiac, neuronal or endocrine ought to preserve both systemic and regional iron levels. The proposed deferiprone-based therapy has provided a paradigm for treating regional types of siderosis without affecting hematological parameters and systemic

  19. Comprehensive analysis of the renal transcriptional response to acute uranyl nitrate exposure

    Directory of Open Access Journals (Sweden)

    Argiles Angel

    2006-01-01

    Full Text Available Abstract Background Chemical and radiological toxicities related to uranium acute exposure have been widely studied in nuclear fuel workers and military personnel. It is well known that uranyl nitrate induces acute renal failure (ARF. However, the mechanisms of this metal-induced injury are not well defined at the molecular level. Results Renal function and histology were assessed in mice receiving uranyl nitrate (UN(+ and controls (UN(-. To identify the genomic response to uranium exposure, serial analysis gene expression (SAGE of the kidney was performed in both groups. Over 43,000 mRNA SAGE tags were sequenced. A selection of the differentially expressed transcripts was confirmed by real-time quantitative PCR and Western blotting. UN(+ animals developed renal failure and displayed the characteristic histological lesions of UN nephropathy. Of the >14,500 unique tags identified in both libraries, 224 had a modified expression level; they are known to participate in inflammation, ion transport, signal transduction, oxidative stress, apoptosis, metabolism, and catabolism. Several genes that were identified had not previously been evaluated within the context of toxic ARF such as translationally controlled tumor protein, insulin like growth factor binding protein 7 and ribosomal protein S29, all apoptosis related genes. Conclusion We report a comprehensive description of the UN induced modifications in gene expression levels, including the identification of genes previously unrelated to ARF. The study of these genes and the metabolisms they control should improve our understanding of toxic ARF and enlighten on the molecular targets for potential therapeutic interventions.

  20. Potential remediation approach for uranium-contaminated groundwaters through potassium uranyl vanadate precipitation

    Energy Technology Data Exchange (ETDEWEB)

    Tokunaga, T.K.; Kim, Y.; Wan, J.

    2009-06-01

    Methods for remediating groundwaters contaminated with uranium (U) through precipitation under oxidizing conditions are needed because bioreduction-based approaches require indefinite supply of electron donor. Although strategies based on precipitation of some phosphate minerals within the (meta)autunite group have been considered for this purpose, thermodynamic calculations for K- and Ca-uranyl phopsphates, meta-ankoleite and autunite, predict that U concentrations will exceed the Maximum Contaminant Level (MCL = 0.13 {micro}M for U) at any pH and pCO{sub 2}, unless phosphate is maintained at much higher concentrations than the sub-{micro}M levels typically found in groundwaters. We hypothesized that potassium uranyl vanadate will control U(VI) concentrations below regulatory levels in slightly acidic to neutral solutions based on thermodynamic data available for carnotite, K{sub 2}(UO{sub 2}){sub 2}V{sub 2}O8. The calculations indicate that maintaining U concentrations below the MCL through precipitation of carnotite will be sustainable in some oxidizing waters having pH in the range of 5.5 to 7, even when dissolution of this solid phase becomes the sole supply of sub-{micro}M levels of V. Batch experiments were conducted in solutions at pH 6.0 and 7.8, chosen because of their very different predicted extents of U(VI) removal. Conditions were identified where U concentrations dropped below its MCL within 1 to 5 days of contact with oxidizing solutions containing 0.2 to 10 mM K, and 0.1 to 20 {micro}M V(V). This method may also have application in extracting (mining) U and V from groundwaters where they both occur at elevated concentrations.

  1. Surface modified magnetic Fe{sub 3}O{sub 4} nanoparticles as a selective sorbent for solid phase extraction of uranyl ions from water samples

    Energy Technology Data Exchange (ETDEWEB)

    Sadeghi, Susan, E-mail: ssadeghi@birjand.ac.ir [Department of Chemistry, Faculty of Science, University of Birjand, P.O. Box. 97175/615, Birjand (Iran, Islamic Republic of); Azhdari, Hoda [Department of Chemistry, Faculty of Science, University of Birjand, P.O. Box. 97175/615, Birjand (Iran, Islamic Republic of); Arabi, Hadi [Magnetism and Superconducting Research Lab, Department of Physics, Faculty of Science, University of Birjand, P.O. Box. 97175/615, Birjand (Iran, Islamic Republic of); Moghaddam, Ali Zeraatkar [Department of Chemistry, Faculty of Science, University of Birjand, P.O. Box. 97175/615, Birjand (Iran, Islamic Republic of)

    2012-05-15

    Highlights: Black-Right-Pointing-Pointer A new sorbent based on functionalized magnetite nanoparticles with quercetin is reported. Black-Right-Pointing-Pointer The quercetin based magnetic nanoparticles could be used as a sorbent to remove toxic uranyl ions from water samples. Black-Right-Pointing-Pointer The sorbent provides a rapidly and easy separation of uranyl ions only by using a permanent magnet. Black-Right-Pointing-Pointer This technique is considered more efficient separation compared to conventional filtering or centrifuging methods for the removing of the sorbent. - Abstract: In this study, silica-coated magnetic nanoparticles modified with quercetin were synthesized by a sol-gel method. These magnetic nanoparticles were assessed as a new solid phase sorbent for extraction of uranyl ions from aqueous solutions. The crystal and chemical structures and magnetic property of the new sorbent were characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), Fourier transform infrared spectrophotometer (FT-IR), and vibration sample magnetometer (VSM). The experimental parameters affecting the extraction efficiency of uranyl ions from aqueous solutions using the synthesized sorbent were optimized by means of the response surface methodology. The adsorption equilibrium of uranyl ions onto the sorbent was explained by Langmuir isotherm and maximum monolayer adsorption capacity was found 12.33 mg/g. The synthesized sorbent was applied to extraction of uranyl ions from different water samples.

  2. Effect of the temperature and oxalic acid in the uranyl sorption in zircon; Efecto de la temperatura y acido oxalico en la sorcion de uranilo en circon

    Energy Technology Data Exchange (ETDEWEB)

    Ordonez R, E.; Almazan T, M. G.; Garcia G, N. [ININ, Departamento de Quimica, Carretera Mexico-Toluca s/n, 52750 Ocoyoacac, Estado de Mexico (Mexico); Hernandez O, R., E-mail: eduardo.ordonez@inin.gob.mx [Instituto Tecnologico de Veracruz, Ingenieria Quimica, Miguel Angel de Quevedo No. 2779, 91860 Veracruz (Mexico)

    2012-10-15

    In this work the results of the temperature effect study are presented on uranyl solutions adsorbed on zirconium silicate (ZrSiO{sub 4}) and also on the compounds formed in surface with oxalic acid. The adsorption isotherms of uranyl on hydrated zircon with NaClO{sub 4} 0.5 M, show an increase of the uranyl sorption efficiency when increasing the temperature from 20 to 4 C with a sudden descent in this efficiency when changing the temperature at 60 C. The uranyl sorption efficiency increases to hydrate the zircon with a solution of oxalic acid 0.1 M, maintaining the same tendency regarding to the temperatures of the sorption in medium NaClO{sub 4} 0.5 M. The complex formation in the zircon surface with organic acids of low molecular weight increases the fixation of the uranyl in solution due to the formation of ternary systems, in the order Zircon/A. Organic/Uranyl, without altering their response to the temperature. (Author)

  3. Sorption of uranyl(VI) cations on suspended silicate: effects of N-donor ligands, carboxylic acids, organic cosolvents, and metal ions

    Energy Technology Data Exchange (ETDEWEB)

    Pathak, P.N.; Choppin, G.R. [Florida State Univ., Tallahassee, FL (United States). Dept. of Chemistry and Biochemistry

    2007-07-01

    Sorption of uranyl ion, UO{sub 2}{sup 2+}, on silicate particles (3.00g/L) was studied in sodium perchlorate solution as a function of pcH and ionic strength at 298 K. The effects of different ligands (e.g., N-donors, carboxylic acids) on the uranyl sorption were investigated. At I = 0.20 M (NaClO{sub 4}), uranyl sorption on silicate increased from ca. 6% (pcH 3.0) to ca. 99% (at pcH 6.5), above which a small decrease was observed. A synergistic enhancement in uranyl sorption was observed in the presence of N-donor ligands such as 1,10-phenanthroline and ethylenediamine in the pcH range 3 to 4.5 as compared to that in the absence of ligands. Carboxylic acids inhibited the sorption in the order: citric acid > malonic acid > nitrilotriacetic acid > iminodiacetic acid > sulfosalicylic acid > succinic acid > glycolic acid. The presence of organic cosolvents such as dimethylsulfoxide, glycerol and tetrahydrofuran had no significant influence on the uranyl sorption profile. Uranyl sorption decreased marginally in the presence of 1.00 x 10{sup -3} M Eu(III). (orig.)

  4. Structure-configurational entropy and its effect on the thermodynamic stability of uranyl phases: With special application for geological disposal of nuclear waste

    Institute of Scientific and Technical Information of China (English)

    CHEN; Fanrong(陈繁荣); Rodney; C.Ewing

    2003-01-01

    Spent UO2 fuel will rapidly be altered to U6+ phases in nuclear waste repositories. Because most uranyl phases are based on sheet or chain structures and usually contain several molecular water groups, site-mixing, vacancies, as well as disorder in the orientation of hydrogen bonds may occur. A systematic survey of the published crystallographic data for uranates, uranyl oxide hydrates, phosphates, silicates, carbonates, and sulfates demonstrates that site-mixing apparently occurs in the structures of at least 31 uranyl phases. Calculations of the ideal site-mixing entropy indicate that the residual contribution that arises from substitution and vacancies to the third-law entropies of some uranyl phases is large. A brief examination of the crystal chemistry of water molecules in uranyl phases suggests that considerable residual entropy may be caused by the disorder of hydrogen bonds associated with interstitial H2O groups. In the geochemical environment that expected to occur in the near-field of nuclear waste repositories, the existence of structure-configurational entropy may reduce the uranium concentration of several log units in solutions equilibrated with some uranyl phases. Therefore, compositional analysis and structural determinations must be made on the samples used in calorimetric measurements, and the calorimetric data must be combined with solubility data to evaluate the thermodynamic stability of the interested phases.

  5. Antiparietal cell antibody test

    Science.gov (United States)

    APCA; Anti-gastric parietal cell antibody; Atrophic gastritis - anti-gastric parietal cell antibody; Gastric ulcer - anti-gastric parietal cell antibody; Pernicious anemia - anti-gastric parietal cell antibody; ...

  6. Supercritical Fluid Extraction of Metal Chelate: A Review.

    Science.gov (United States)

    Ding, Xin; Liu, Qinli; Hou, Xiongpo; Fang, Tao

    2017-03-04

    Supercritical fluid extraction (SFE), as a new green extraction technology, has been used in extracting various metal species. The solubilities of chelating agents and corresponding metal chelates are the key factors which influence the efficiency of SFE. Other main properties of them such as stability and selectivity are also reviewed. The extraction mechanisms of mainly used chelating agents are explained by typical examples in this paper. This is the important aspect of SFE of metal ions. Moreover, the extraction efficiencies of metal species also depend on other factors such as temperature, pressure, extraction time and matrix effect. The two main complexation methods namely in-situ and on-line chelating SFE are described in detail. As an efficient chelating agent, tributyl phosphate-nitric acid (TBP-HNO3) complex attracts much attention. The SFE of metal ions, lanthanides and actinides as well as organometallic compounds are also summarized. With the proper selection of ligands, high efficient extraction of metal species can be obtained. As an efficient sample analysis method, supercritical fluid chromatography (SFC) is introduced in this paper. Recently, the extraction method combining ionic liquids (ILs) with supercritical fluid has been becoming a novel technology for treating metal ions. The kinetics related to SFE of metal species is discussed with some specific examples.

  7. Ab initio coordination chemistry for nickel chelation motifs.

    Science.gov (United States)

    Sudan, R Jesu Jaya; Kumari, J Lesitha Jeeva; Sudandiradoss, C

    2015-01-01

    Chelation therapy is one of the most appreciated methods in the treatment of metal induced disease predisposition. Coordination chemistry provides a way to understand metal association in biological structures. In this work we have implemented coordination chemistry to study nickel coordination due to its high impact in industrial usage and thereby health consequences. This paper reports the analysis of nickel coordination from a large dataset of nickel bound structures and sequences. Coordination patterns predicted from the structures are reported in terms of donors, chelate length, coordination number, chelate geometry, structural fold and architecture. The analysis revealed histidine as the most favored residue in nickel coordination. The most common chelates identified were histidine based namely HHH, HDH, HEH and HH spaced at specific intervals. Though a maximum coordination number of 8 was observed, the presence of a single protein donor was noted to be mandatory in nickel coordination. The coordination pattern did not reveal any specific fold, nevertheless we report preferable residue spacing for specific structural architecture. In contrast, the analysis of nickel binding proteins from bacterial and archeal species revealed no common coordination patterns. Nickel binding sequence motifs were noted to be organism specific and protein class specific. As a result we identified about 13 signatures derived from 13 classes of nickel binding proteins. The specifications on nickel coordination presented in this paper will prove beneficial for developing better chelation strategies.

  8. Ab initio coordination chemistry for nickel chelation motifs.

    Directory of Open Access Journals (Sweden)

    R Jesu Jaya Sudan

    Full Text Available Chelation therapy is one of the most appreciated methods in the treatment of metal induced disease predisposition. Coordination chemistry provides a way to understand metal association in biological structures. In this work we have implemented coordination chemistry to study nickel coordination due to its high impact in industrial usage and thereby health consequences. This paper reports the analysis of nickel coordination from a large dataset of nickel bound structures and sequences. Coordination patterns predicted from the structures are reported in terms of donors, chelate length, coordination number, chelate geometry, structural fold and architecture. The analysis revealed histidine as the most favored residue in nickel coordination. The most common chelates identified were histidine based namely HHH, HDH, HEH and HH spaced at specific intervals. Though a maximum coordination number of 8 was observed, the presence of a single protein donor was noted to be mandatory in nickel coordination. The coordination pattern did not reveal any specific fold, nevertheless we report preferable residue spacing for specific structural architecture. In contrast, the analysis of nickel binding proteins from bacterial and archeal species revealed no common coordination patterns. Nickel binding sequence motifs were noted to be organism specific and protein class specific. As a result we identified about 13 signatures derived from 13 classes of nickel binding proteins. The specifications on nickel coordination presented in this paper will prove beneficial for developing better chelation strategies.

  9. Mechanistic study of the interaction of uranyl ions with zirconium oxide and zirconium silicate; Etude mecanistique de l'interaction des ions uranyle avec l'oxyde et le silicate de zirconium

    Energy Technology Data Exchange (ETDEWEB)

    Lomenech, C

    2002-04-01

    This work deals with structural and thermodynamic studies of the sorption of uranyl species on zircon and zirconia. After determination of the specific areas, of the pH of the isoelectric points, and of the sorption site numbers, thermodynamic data were obtained using alpha spectrometry, for different uranyl concentrations, different background electrolytes (NaClO{sub 4} or KNO{sub 3}) and different ionic strengths. The structural identification of the surface complexes and sorption sites was carried out using several spectroscopies: XPS spectroscopy allowed a determination of the nature of the sorption sites ({identical_to}Zr-O- on zirconia and {identical_to}Si-O- on zircon). Whereas fluorescence decay measurements gave the number of surface species, the combined use of XPS spectroscopy and laser spectro-fluorimetry enabled us to correlate differences in bonding energies and emission wavelengths with differences in the nature of the background electrolyte or in the pH of sorption; DRIFT spectroscopy was a powerful tool for the determination of the presence of sorbed uranyl nitrate species. EXAFS results clearly showed a splitting of the equatorial oxygen atoms in two shells, corresponding to a polydentate, inner-sphere complex. EXAFS results also indicated strong similarities between dry samples and in situ experiments, which confirms the validity of all the spectroscopic measurements. Macroscopic thermodynamic data were then modeled using a surface complexation model (2 pK and constant capacitance models), the results of the structural study being used as constraints for the simulation code FITEQL. (author)

  10. Chelation therapy in intoxications with mercury, lead and copper

    DEFF Research Database (Denmark)

    Cao, yang; Skaug, Marit Aralt; Andersen, Ole;

    2015-01-01

    mobilize deposits of mercury as well as of lead into the urine. These drugs can be administered orally and have relatively low toxicity compared to the classical antidote dimercaptopropanol (BAL). d-Penicillamine has been widely used in copper overload, although 2,3-dimercaptosuccinic acid......In the present review we provide an update of the appropriate use of chelating agents in the treatment of intoxications with compounds of mercury, lead and copper. The relatively new chelators meso-2,3-dimercaptosuccinic acid (DMSA) and 2,3-dimercapto-propanesulphonate (DMPS) can effectively...... or tetrathiomolybdate may be more suitable alternatives today. In copper-toxicity, a free radical scavenger might be recommended as adjuvant to the chelator therapy...

  11. Preparation and Properties of Iminodiacetic Acid Chelate Fiber

    Directory of Open Access Journals (Sweden)

    QIAN Jin-xin

    2016-07-01

    Full Text Available The iminodiacetic acid chelate fiber(IDACF which has a property of selective adsorption, was fabricated by amination and carboxylation using chloramethylated polypropylene grafted styrene fiber as raw material. Orthogonal experiment was adopted to study the effect of temperature, time, liquor ratio and the amount of chloroacetic acid on carboxylation reaction. The maximum adsorption capacity of iminodiacetic acid chelate fiber to Cu2+ is 65.54mg·g-1, which is 10.52 times of that of Fe3+. Elementary analysis(EA, Fourier transform infrared spectrum(FT-IR, scanning electron microscopy(SEM and thermogrametry(TG were used to characterize the structure and the properties of the iminodiacetic acid chelate fiber. The results show that iminodiacetic acid has been transformed to the raw fiber successfully after amination and carboxymethylation, and IDACF has good thermal stability.

  12. Albumin microspheres labeled with Ga-67 by chelation: concise communication.

    Science.gov (United States)

    Hnatowich, D J; Schlegel, P

    1981-07-01

    Albumin microspheres have been synthesized eith EDTA and DTPA chelating groups covalently bound to their surface. The microspheres may be labeled with Ga-67 at high yield (97 +/- 2%) by transcomplexation from a 0.1 M Ga-67 acetate solution. With EDTA microspheres the resulting label dissociates only slightly after no detectable dissociation over this period. By contrast, microspheres without chelating groups lose their label virtually completely under these conditions. Following intravenous administration of sized Ga-67 DTPA microspheres in mice, about (84 +/- 16)% of the activity localizes in the lungs at 5 min, with (60 +/- 7)% remaining after 2 hr. Since labeling is by chelation, the microspheres may also be tagged with other metallic radionuclides

  13. Synthesis and Characteristics of A Novel Heavy Metal Ions Chelator

    Institute of Scientific and Technical Information of China (English)

    LIU Zhuannian; SONG Yejing; HAN Xiaogang

    2012-01-01

    Polyacrylamide-urea-sulfanilamide(PUS) was prepared as a novel heavy metal ions chelator and successfully used to simultaneously remove heavy metals from wastewater effluents.The effects of reaction parameters (sodium hydroxide,material ratio,temprature and contact time) were monitored to specify the best synthesis conditions.PUS was chemically characterized by means of infrared spectroscopy (FTIR) and ultraviolet-visible (UV-Vis).The simultaneous chelation performance of PUS towards selected heavy metals ions,Ni2+,Cu2+,Pb2+,Zn2+,Cd2+ was discussed,showing that Ni2+,Cu2+,Pb2+,Zn2+ could be better chelated.It is indicated that the synthesized PUS is a potential remediation material when used for the treatment of wastewater containing metal ions.

  14. Inositol hexa-phosphate: a potential chelating agent for uranium

    Energy Technology Data Exchange (ETDEWEB)

    Cebrian, D.; Tapia, A.; Real, A.; Morcillo, M.A. [Radiobiology Laboratory, Radiation Dosimetry Unit, Department of Environment, CIEMAT, Avda Complutense 22, 28040 Madrid (Spain)

    2007-07-01

    Chelation therapy is an optimal method to reduce the radionuclide-related risks. In the case of uranium incorporation, the treatment of choice is so far i.v infusion of a 1.4% sodium bicarbonate solution, but the efficacy has been proved to be not very high. In this study, we examine the efficacy of some substances: bicarbonate, citrate, diethylenetriamine pentaacetic acid (DTPA), ethidronate (EHBP) and inositol hexa-phosphate (phytic acid) to chelate uranium using a test developed by Braun et al. Different concentrations of phytic acid, an abundant component of plant seeds that is widely distributed in animal cells and tissues in substantial levels, were tested and compared to the same concentrations of sodium citrate, bicarbonate, EHBP and DTPA. The results showed a strong affinity of inositol hexa-phosphate for uranium, suggesting that it could be an effective chelating agent for uranium in vivo. (authors)

  15. Efficacy of chelation therapy to remove aluminium intoxication.

    Science.gov (United States)

    Fulgenzi, Alessandro; De Giuseppe, Rachele; Bamonti, Fabrizia; Vietti, Daniele; Ferrero, Maria Elena

    2015-11-01

    There is a distinct correlation between aluminium (Al) intoxication and neurodegenerative diseases (ND). We demonstrated how patients affected by ND showing Al intoxication benefit from short-term treatment with calcium disodium ethylene diamine tetraacetic acid (EDTA) (chelation therapy). Such therapy further improved through daily treatment with the antioxidant Cellfood. In the present study we examined the efficacy of long-term treatment, using both EDTA and Cellfood. Slow intravenous treatment with the chelating agent EDTA (2 g/10 mL diluted in 500 mL physiological saline administered in 2 h) (chelation test) removed Al, which was detected (using inductively coupled plasma mass spectrometry) in urine samples collected from patients over 12 h. Patients that revealed Al intoxication (expressed in μg per g creatinine) underwent EDTA chelation therapy once a week for ten weeks, then once every two weeks for a further six or twelve months. At the end of treatment (a total of 22 or 34 chelation therapies, respectively), associated with daily assumption of Cellfood, Al levels in the urine samples were analysed. In addition, the following blood parameters were determined: homocysteine, vitamin B12, and folate, as well as the oxidative status e.g. reactive oxygen species (ROS), total antioxidant capacity (TAC), oxidized LDL (oxLDL), and glutathione. Our results showed that Al intoxication reduced significantly following EDTA and Cellfood treatment, and clinical symptoms improved. After treatment, ROS, oxLDL, and homocysteine decreased significantly, whereas vitamin B12, folate and TAC improved significantly. In conclusion, our data show the efficacy of chelation therapy associated with Cellfood in subjects affected by Al intoxication who have developed ND.

  16. Chelation of heavy metals by potassium butyl dithiophosphate

    Institute of Scientific and Technical Information of China (English)

    Ying Xu; Zhigang Xie; Lu Xue

    2011-01-01

    Potassium butyl dithiophosphate (PBD) was developed and introduced as a new chelating agent for heavy metal removal.The synthesized PBD were characterized by IR and NMR.The effects of pH, chelating agent dosage, and other heavy metal ions on the performance of PBD in Cd2+ removal from water are investigated.Experimental results showed that the chelating agent could be used to treat acidic heavy metal wastewater.The Cd2+ removal was not affected by solution pH value within the range of 2 to 6.The Cd2+ removal rate could reach over 99%.Therefore, the deficiency of the precipitation process using hydroxide under alkaline condition can be overcome.Without the need for pH adjustment, the method could save on costs.If Cd2+ co-exists with Pb2+ and Cu2+, the affinity of the chelating agent with these three heavy metal ions was in the order of: Cu2+ > Pb2+ > Cd2+.Through PBD chelating precipitation,all the contents of Pb2+, Cd2+, and Cu2+ in wastewater met the standard levels through a one-step treatment.The one-step treatment process was superior to the process (sectional treatment is required) of precipitation with hydroxide.When the pH was between 3 and 11, the amount of leached chelated Cd2+ was much lower than that obtained by precipitation with hydroxide.Therefore, the risk of environmental pollution could be further reduced.

  17. Structural determination of some uranyl compounds by vibrational spectroscopy; Determinacion estructural de algunos compuestos de uranilo por espectroscopia vibracional

    Energy Technology Data Exchange (ETDEWEB)

    Rodriguez S, A.; Martinez Q, E

    1990-07-15

    The vibrational spectra of different uranyl compounds has been studied and of it spectral information has been used the fundamental asymmetric vibrational frequency, to determine the length and constant bond force U=O by means of the combination of the concept of absorbed energy and the mathematical expression of Badger modified by Jones. It is intended a factor that simplifies the mathematical treatment and the results are compared with the values obtained for other methods. (Author)

  18. Role of aqueous sulfide and sulfate-reducing bacteria in the kinetics and mechanisms of the reduction of uranyl ion

    Energy Technology Data Exchange (ETDEWEB)

    Mohagheghi, A.

    1985-01-01

    Formation of sedimentary rock-hosted uranium ore deposits is thought to have resulted from the reduction by aqueous sulfide species of relatively soluble uranyl ion (U(VI)) to insoluble uranium(IV) oxides and silicates. The origin of this H/sub 2/S in such deposits can be either biogenic or abiogenic. Therefore, the kinetics and mechanism of uranyl ion reduction by aqueous sulfide, and the effect of several key variables on the reduction process in non-bacterial (sterile) systems was studied. The role of both pure and mixed cultures of sulfate-reducing bacteria on the reduction process was also investigated. In sterile systems the reduction reaction generally occurred by a two step reaction sequence. Uranium(V) (as UO/sub 2//sup +/) and U(IV) (as UO/sub 2/ the mineral uraninite) were the intermediate and final products, respectively. The initial concentration of uranyl ion required for reaction initiation had a minimum value of 0.8 ppm at pH 7, and was higher at pH values less than or greater than 7. An induction period was observed in all experiments. No reduction was observed after 8 hours at pH 8. Although increasing ionic strength increased the length of the induction period, it also increased the rate of the reduction of UO/sub 2//sup +/ in the second step. No reaction was observed under any experimental conditions with initial UO/sub 2//sup 2 +/ concentration less than 0.1 ppm, which is thought to be typical for ore forming solutions. However, by absorbing uranyl ion onto kaolinite, the reduction by H/sub 2/S occurred at lower UO/sub 2//sup 2 +/ concentrations (approx. 0.1 ppm) in that in the homogeneous system. Thus, adsorption may play a significant role in the reduction and therefore in the formation of ore deposits.

  19. Antibody Conjugates: From Heterogeneous Populations to Defined Reagents

    Directory of Open Access Journals (Sweden)

    Patrick Dennler

    2015-08-01

    Full Text Available Monoclonal antibodies (mAbs and their derivatives are currently the fastest growing class of therapeutics. Even if naked antibodies have proven their value as successful biopharmaceuticals, they suffer from some limitations. To overcome suboptimal therapeutic efficacy, immunoglobulins are conjugated with toxic payloads to form antibody drug conjugates (ADCs and with chelating systems bearing therapeutic radioisotopes to form radioimmunoconjugates (RICs. Besides their therapeutic applications, antibody conjugates are also extensively used for many in vitro assays. A broad variety of methods to functionalize antibodies with various payloads are currently available. The decision as to which conjugation method to use strongly depends on the final purpose of the antibody conjugate. Classical conjugation via amino acid residues is still the most common method to produce antibody conjugates and is suitable for most in vitro applications. In recent years, however, it has become evident that antibody conjugates, which are generated via site-specific conjugation techniques, possess distinct advantages with regard to in vivo properties. Here, we give a comprehensive overview on existing and emerging strategies for the production of covalent and non-covalent antibody conjugates.

  20. Chelation in metal intoxication—Principles and paradigms

    DEFF Research Database (Denmark)

    Aaseth, Jan; Skaug, Marit Aralt; Cao, Yang;

    2015-01-01

    of heavy metal poisoning, and available as capsules for oral use. In copper overload, DMSA appears to be a potent antidote, although d-penicillamine is still widely used. In the chelation of iron, the thiols are inefficient, since iron has higher affinity for ligands with nitrogen and oxygen, but the new...... oral iron antidotes deferiprone and desferasirox have entered into the clinical arena. Comparisons of these agents and deferoxamine infusions are in progress. General principles for research and development of new chelators are briefly outlined in this review...

  1. SHINE and Mini-SHINE Column Designs for Recovery of Mo from 140 g-U/L Uranyl Sulfate

    Energy Technology Data Exchange (ETDEWEB)

    Stepinski, Dominique C. [Argonne National Lab. (ANL), Argonne, IL (United States); Vandegrift, George F. [Argonne National Lab. (ANL), Argonne, IL (United States)

    2016-09-01

    Argonne is assisting SHINE Medical Technologies (SHINE) in their efforts to develop an accelerator-driven process that utilizes a uranyl-sulfate solution for the production of fission Mo 99. In an effort to design a Mo-recovery system for the SHINE project using low-enriched uranium (LEU), we conducted batch, breakthrough, and pulse tests to determine the Mo isotherm, mass-transfer zone (MTZ), and system parameters for a 130 g-U/L uranyl sulfate solution at pH 1 and 80°C, as described previously.1,2 The VERSE program was utilized to calculate the MTZ under various loading times and velocities. The results were then used to design Mo separation and recovery columns employing a pure titania sorbent (110-μm particles, S110, and 60 Å pore size). The plant-scale column designs assume Mo will be separated from 271 L of a 141 g-U/L uranyl sulfate solution, pH 1, containing 0.0023 mM Mo. The VERSE-designed recovery systems have been tested and verified in laboratory-scale experiments, and this approach was found to be very successful.

  2. METAL BINDING PROPERTIES OF A MONOCLONAL ANTIBODY DIRECTED TOWARDS METAL-CHELATE COMPLEXES. (R824029)

    Science.gov (United States)

    The perspectives, information and conclusions conveyed in research project abstracts, progress reports, final reports, journal abstracts and journal publications convey the viewpoints of the principal investigator and may not represent the views and policies of ORD and EPA. Concl...

  3. Influence of uranyl speciation and iron oxides on uranium biogeochemical redox reactions

    Energy Technology Data Exchange (ETDEWEB)

    Stewart, B.D.; Amos, R.T.; Nico, P.S.; Fendorf, S.

    2010-03-15

    Uranium is a pollutant of concern to both human and ecosystem health. Uranium's redox state often dictates its partitioning between the aqueous- and solid-phases, and thus controls its dissolved concentration and, coupled with groundwater flow, its migration within the environment. In anaerobic environments, the more oxidized and mobile form of uranium (UO{sub 2}{sup 2+} and associated species) may be reduced, directly or indirectly, by microorganisms to U(IV) with subsequent precipitation of UO{sub 2}. However, various factors within soils and sediments may limit biological reduction of U(VI), inclusive of alterations in U(VI) speciation and competitive electron acceptors. Here we elucidate the impact of U(VI) speciation on the extent and rate of reduction with specific emphasis on speciation changes induced by dissolved Ca, and we examine the impact of Fe(III) (hydr)oxides (ferrihydrite, goethite and hematite) varying in free energies of formation on U reduction. The amount of uranium removed from solution during 100 h of incubation with S. putrefaciens was 77% with no Ca or ferrihydrite present but only 24% (with ferrihydrite) and 14% (no ferrihydrite) were removed for systems with 0.8 mM Ca. Imparting an important criterion on uranium reduction, goethite and hematite decrease the dissolved concentration of calcium through adsorption and thus tend to diminish the effect of calcium on uranium reduction. Dissimilatory reduction of Fe(III) and U(VI) can proceed through different enzyme pathways, even within a single organism, thus providing a potential second means by which Fe(III) bearing minerals may impact U(VI) reduction. We quantify rate coefficients for simultaneous dissimilatory reduction of Fe(III) and U(VI) in systems varying in Ca concentration (0 to 0.8 mM), and using a mathematical construct implemented with the reactive transport code MIN3P, we reveal the predominant influence of uranyl speciation, specifically the formation of uranyl

  4. Laccase Immobilization by Chelated Metal Ion Coordination Chemistry

    Directory of Open Access Journals (Sweden)

    Qingqing Wang

    2014-09-01

    Full Text Available In this work, amidoxime polyacrylonitrile (AOPAN nanofibrous membrane was prepared by a reaction between PAN nanofibers and hydroxylamine hydrochloride. The AOPAN nanofibrous membranes were used for four metal ions (Fe3+, Cu2+, Ni2+, Cd2+ chelation under different conditions. Further, the competition of different metal ions coordinating with AOPAN nanofibrous membrane was also studied. The AOPAN chelated with individual metal ion (Fe3+, Cu2+, Ni2+, Cd2+ and also the four mixed metal ions were further used for laccase (Lac immobilization. Compared with free laccase, the immobilized laccase showed better resistance to pH and temperature changes as well as improved storage stability. Among the four individual metal ion chelated membranes, the stability of the immobilized enzymes generally followed the order as Fe–AOPAN–Lac > Cu–AOPAN–Lac > Ni–AOPAN–Lac > Cd–AOPAN–Lac. In addition, the immobilized enzyme on the carrier of AOPAN chelated with four mixed metal ions showed the best properties.

  5. Iron chelator daphnetin against Pneumocystis carinii in vitro

    Institute of Scientific and Technical Information of China (English)

    叶彬; 郑玉强; 武卫华; 张静

    2004-01-01

    Background Although there are several drugs and drug combinations for the treatment of Pneumocystis carinii (P. carinii) pneumonia, all drugs have the toxicity as well as low efficacy. Iron chelators have been proposed as a source of new drugs for combating these infections. We hypothesized that iron chelators would suppress the growth of P. carinii by deprivation of the nutritional iron required for growth. In this study, a short-term axenic culture system of P. carinii was established. Daphnetin (7,8-dihydroxycoumarin), a known iron chelator, was demonstrated to exhibit in vitro activity against P. carinii in this system. Methods P. carinii organisms were obtained from the lungs of immunosuppressed rats. The culture system consisted of Iscove Dulbecco Eagle's Minimum Essential Medium (IMDM), supplemented with S-adenosyl-L-methionine, N-acetylglucosamine, putrescine, L-cysteine, L-glutamine, 2-mercaptoethanol, and fetal bovine serum, and was maintained at 37℃, in 5% CO2, 95% O2, at the optimal pH of 8.0. The culture system was used to assess the effect of daphnetin on the proliferation of P. carinii organisms. The ultrastructures of the treated organisms were observed by transmission electron microscopy.Conclusions Daphnetin can suppress the growth of P. carinii in vitro. The efficacy of daphnetin in suppressing the the growth of P. carinii in vitro is related to its ability to chelate iron.

  6. Encapsulation and retention of chelated-copper inside hydrophobic nanoparticles

    DEFF Research Database (Denmark)

    Hervella, Pablo; Ortiz, Elisa Parra; Needham, David

    2016-01-01

    ) Chelate copper into the octaethyl porphyrin; (3) Encapsulate OEP-Cu in nanoparticles: the encapsulation efficiency of copper into liquid nanoparticles (LNP), solid nanoparticles (SNP) and phospholipid liposomes (PL) was evaluated by UV-Vis and atomic absorption spectroscopy; (4) Retain the encapsulated...

  7. Chelation of aluminum by combining deferasirox and deferiprone in rats.

    Science.gov (United States)

    Saljooghi, Amir Shokooh

    2012-09-01

    The hypothesis that two known chelators deferasirox and deferiprone (L1) might be more efficient as combined treatment than as single therapies in removing aluminum from the body was tested in a new acute rat model. Seven-week-old male Wistar rats received chelators: deferasirox (orally [p.o.]), L1 (p.o.) or deferasirox + L1 as 100 or 200 mg/kg dose half an hour after a single intraperitoneal administration of 6 mg Al/kg body weight in the form of chloride. Serum aluminum concentration, urinary aluminum and iron excretions were determined by graphite furnace atomic absorption spectrometry. Both chelators were effective only at the higher dose level. While deferasirox was more effective than L1 in enhancing urinary aluminum excretion, L1 was more effective than deferasirox in enhancing urinary iron excretion. In the combined treatment group, deferasirox did not increase the L1 effect on aluminum and L1 did not increase the effect of deferasirox on iron elimination. Our results support the usefulness of this animal model for preliminary in vivo testing of aluminum chelators. Urinary values were more useful due to the high variability of serum results.

  8. Iron chelating active packaging: Influence of competing ions and pH value on effectiveness of soluble and immobilized hydroxamate chelators.

    Science.gov (United States)

    Ogiwara, Yoshiko; Roman, Maxine J; Decker, Eric A; Goddard, Julie M

    2016-04-01

    Many packaged foods utilize synthetic chelators (e.g. ethylenediaminetetraacetic acid, EDTA) to inhibit iron-promoted oxidation or microbial growth which would result in quality loss. To address consumer demands for all natural products, we have previously developed a non-migratory iron chelating active packaging material by covalent immobilization of polyhydroxamate and demonstrated its efficacy in delaying lipid oxidation. Herein, we demonstrate the ability of this hydroxamate-functionalized iron chelating active packaging to retain iron chelating capacity; even in the presence of competing ions common in food. Both immobilized and soluble hydroxamate chelators retained iron chelating capacity in the presence of calcium, magnesium, and sodium competing ions, although at pH 5.0 the presence of calcium reduced immobilized hydroxamate iron chelation. A strong correlation was found between colorimetric and mass spectral analysis of iron chelation by the chelating packaging material. Such chelating active packaging may support reducing additive use in product formulations, while retaining quality and shelf life.

  9. Uranyl(VI) nitrate salts: modeling thermodynamic properties using the binding mean spherical approximation theory and determination of "fictive" binary data.

    Science.gov (United States)

    Ruas, Alexandre; Bernard, Olivier; Caniffi, Barbara; Simonin, Jean-Pierre; Turq, Pierre; Blum, Lesser; Moisy, Philippe

    2006-02-23

    This work is aimed at a description of the thermodynamic properties of highly concentrated aqueous solutions of uranyl nitrate at 25 degrees C. A new resolution of the binding mean spherical approximation (BIMSA) theory, taking into account 1-1 and also 1-2 complex formation, is developed and used to reproduce, from a simple procedure, experimental uranyl nitrate osmotic coefficient variation with concentration. For better consistency of the theory, binary uranyl perchlorate and chloride osmotic coefficients are also calculated. Comparison of calculated and experimental values is made. The possibility of regarding the ternary system UO(2)(NO(3))(2)/HNO(3)/H(2)O as a "simple" solution (in the sense of Zdanovskii, Stokes, and Robinson) is examined from water activity and density measurements. Also, an analysis of existing uranyl nitrate binary data is proposed and compared with our obtained data. On the basis of the concept of "simple" solution, values for density and water activity for the binary system UO(2)(NO(3))(2)/H(2)O are proposed in a concentration range on which uranyl nitrate precipitates from measurements on concentrated solutions of the ternary system UO(2)(NO(3))(2)/HNO(3)/H(2)O. This new set of binary data is "fictive" in the sense that the real binary system is not stable chemically. Finally, a new, interesting predictive capability of the BIMSA theory is shown.

  10. Improvement of the cloud point extraction of uranyl ions by the addition of ionic liquids.

    Science.gov (United States)

    Gao, Song; Sun, Taoxiang; Chen, Qingde; Shen, Xinghai

    2013-12-15

    The cloud point extraction (CPE) of uranyl ions by different kinds of extractants in Triton X-114 (TX-114) micellar solution was investigated upon the addition of ionic liquids (ILs) with various anions, i.e., bromide (Br(-)), tetrafluoroborate (BF4(-)), hexafluorophosphate (PF6(-)) and bis[(trifluoromethyl)sulfonyl]imide (NTf2(-)). A significant increase of the extraction efficiency was found on the addition of NTf2(-) based ILs when using neutral extractant tri-octylphosphine oxide (TOPO), and the extraction efficiency kept high at both nearly neutral and high acidity. However, the CPE with acidic extractants, e.g., bis(2-ethylhexyl) phosphoric acid (HDEHP) and 8-hydroxyquinoline (8-HQ) which are only effective at nearly neutral condition, was not improved by ILs. The results of zeta potential and (19)F NMR measurements indicated that the anion NTf2(-) penetrated into the TX-114 micelles and was enriched in the surfactant-rich phase during the CPE process. Meanwhile, NTf2(-) may act as a counterion in the CPE of UO2(2+) by TOPO. Furthermore, the addition of IL increased the separation factor of UO2(2+) and La(3+), which implied that in the micelle TOPO, NTf2(-) and NO3(-) established a soft template for UO2(2+). Therefore, the combination of CPE and IL provided a supramolecular recognition to concentrate UO2(2+) efficiently and selectively.

  11. Critical Parameters of Complex Geometries of Intersecting Cylinders Containing Uranyl Nitrate Solution

    Energy Technology Data Exchange (ETDEWEB)

    J. B. Briggs (INEEL POC); R. E. Rothe

    1999-06-14

    About three dozen previously unreported critical configurations are presented for very complex geometries filled with high concentration enriched uranyl nitrate solution. These geometries resemble a tall, thin Central Column (or trunk of a ''tree'') having long, thin arms (or ''branches'') extending up to four directions off the column. Arms are equally spaced from one another in vertical planes, and that spacing ranges from arms in contact to quite wide spacings. Both the Central Column and the many different arms are critically safe by themselves with each, alone, is filled with fissile solution; but, in combination, criticality occurs due to the interactions between arms and the column. Such neutronic interactions formed the principal focus of this study. While these results are fresh to the nuclear criticality safety industry and to those seeking novel experiments against which to validate computer codes, the experiments, themselves, are not recent. Over 100 experiments were performed at the Rocky Flats Critical Mass Laboratory between September, 1967, and February of the following year.

  12. Critical Parameters of Complex Geometry Intersecting Cylinders Containing Uranyl Nitrate Solution

    Energy Technology Data Exchange (ETDEWEB)

    Rothe, Robert Emil; Briggs, Joseph Blair

    1999-06-01

    About three dozen previously unreported critical configurations are presented for very complex geometries filled with high concentration enriched uranyl nitrate solution. These geometries resemble a tall, thin Central Column (or trunk of a "tree") having long, thin arms (or "branches") extending up to four directions off the column. Arms are equally spaced from one another in vertical planes; and that spacing ranges from arms in contact to quite wide spacings. Both the Central Column and the many different arms are critically safe by themselves when each, alone, is filled with fissile solution; but, in combination, criticality occurs due to the interactions between arms and the column. Such neutronic interactions formed the principal focus of this study. While these results are fresh to the nuclear criticality safety industry and to those seeking novel experiments against which to validate computer codes, the experiments, themselves, are not recent. Over 100 experiments were performed at the Rocky Flats Critical Mass Laboratory between September, 1967, and February of the following year.

  13. Hydrothermal Synthesis, Crystal Structure and Luminescent Properties of an Organically Templated 2-D Uranyl Sulfate

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    An organically templated 2-D uranyl sulfate, {(C2H8N)[(UO2)Cl(SO4)(H2O)]}n 1, has been hydrothermally synthesized . The crystal and molecular structures have been determined by X-ray crystallography method and spectral techniques. 1 belongs to mono- clinic, space group P21/c with a = 8.3545(17), b = 10.550(2), c = 12.370(3)(A), β = 102.64(3)°, V = 1063.9(4)(A)3, Mr = 464.64, Dc = 2.901 g/cm3, F(000) = 836, μ = 15.710 mm-1, Z = 4, the final R = 0.0286 and wR = 0.0685 for 10164 observed reflections with I > 2σ(I). 1 presents a two-dimensional layer-like structure constructed from infinite anionic [(UO2)Cl(H2O)(SO4)]- layers with [C2H8N]+ cations balancing the charge and a number of intermolecular hydrogen bonds (C-H…O and O-H…Cl) existing in the solid state. The fluorescence properties of 1 have also been discussed.

  14. Synthesis, structural investigation and kinetic studies of uranyl(VI) unsymmetrical Schiff base complexes

    Indian Academy of Sciences (India)

    Zahra Asadi; Mozaffar Asadi; Azade Zeinali; Mohammad Ranjkeshshorkaei; Karla Fejfarova; Vaclav Eigner; Michal Dusek; Aliakbar Dehnokhalaji

    2014-11-01

    Uranyl(VI) complexes with unsymmetrical N2O2 Schiff base ligands were synthesized and characterized. Their characterization was performed using UV-Vis, 1H NMR, cyclic voltammetry, single-crystal X-ray crystallography, IR, TG and C.H.N. techniques. X-ray crystallography of the complexes show that beside coordination of the tetradentate Schiff base, one DMF molecule is also coordinated. In order to investigate the effect of the substitutional groups of the Schiff base on the oxidation and reduction potentials, we used the cyclic voltammetry method. Electrochemistry of these complexes showed that the presence of electron releasing groups accelerates oxidation of the complexes. The kinetics of thermal decomposition was studied using thermal gravimetric method (TG) and Coats-Redfern equation. According to Coats-Redfern plots, the kinetics of thermal decomposition of the studied complexes is first-order in all stages. Also the kinetics and mechanism of the exchange reaction of the coordinated solvent with tributylphosphine was carried out in solution, using spectrophotometric method. As a result, the second order rate constants at four temperatures and the activation parameters were calculated showing an associative mechanism for all corresponding complexes. It was concluded that the steric and the electronic properties of the complexes influence the reaction rate significantly.

  15. Sorption of strontium on uranyl peroxide: implications for a high-level nuclear waste repository.

    Science.gov (United States)

    Sureda, Rosa; Martínez-Lladó, Xavier; Rovira, Miquel; de Pablo, Joan; Casas, Ignasi; Giménez, Javier

    2010-09-15

    Strontium-90 is considered the most important radioactive isotope in the environment and one of the most frequently occurring radionuclides in groundwaters at nuclear facilities. The uranyl peroxide studtite (UO2O2 . 4H2O) has been observed to be formed in spent nuclear fuel leaching experiments and seems to have a relatively high sorption capacity for some radionuclides. In this work, the sorption of strontium onto studtite is studied as a function of time, strontium concentration in solution and pH. The main results obtained are (a) sorption is relatively fast although slower than for cesium; (b) strontium seems to be sorbed via a monolayer coverage of the studtite surface, (c) sorption has a strong dependence on ionic strength, is negligible at acidic pH, and increases at neutral to alkaline pH (almost 100% of the strontium in solution is sorbed above pH 10). These results point to uranium secondary solid phase formation on the spent nuclear fuel as an important mechanism for strontium retention in a high-level nuclear waste repository (HLNW).

  16. A new low temperature route to uranyl borates with structural variations

    Energy Technology Data Exchange (ETDEWEB)

    Wu, Shijun [Kiel Univ. (Germany). Inst. fuer Geowissenschaften; Chinese Academy of Sciences, Guangzhou (China). Guangzhou Inst. of Geochemistry; Forschungszentrum Juelich GmbH (Germany). Inst. fuer Energie- und Klimaforschung (IEK-6); Wang, Shuao [Notre Dame Univ., IN (United States). Dept. of Civil Engineering and Geological Sciences; Notre Dame Univ., IN (United States). Dept. of Chemistry and Biochememistry; Lawrence Berkeley Lab., Berkeley, CA (United States). Actinide Chemistry Group; California Univ., Berkeley, CA (United States). Dept. of Chemistry; Polinski, Matthew J. [Notre Dame Univ., IN (United States). Dept. of Civil Engineering and Geological Sciences; Notre Dame Univ., IN (United States). Dept. of Chemistry and Biochememistry; Depmeier, Wulf [Kiel Univ. (Germany). Inst. fuer Geowissenschaften; Albrecht-Schmitt, Thomas E. [Florida State Univ., Tallahassee, FL (United States). Dept. of Chemistry and Biochemistry; Alekseev, Evgeny V. [Forschungszentrum Juelich GmbH (Germany). Inst. fuer Energie- und Klimaforschung (IEK-6); RWTH Aachen Univ. (Germany). Inst. fuer Kristallographie

    2013-10-01

    Three new uranyl borates, K(UO{sub 2})(BO{sub 3}) (1), Rb(UO{sub 2})(BO{sub 3}) (2) and Cs(UO{sub 2})(BO{sub 3}) (3) have been prepared using B{sub 2}O{sub 3} fluxes at 1000 C. 1 and 3 can also be synthesized using potassium tetraborate tetrahydrate as a molten flux at 290 C, which provides a new low temperature route to prepare actinide borates. 1 possesses an a-uranophane anion sheet topology identical to that in the previously reported compounds Li(UO{sub 2})(BO{sub 3}) and Na(UO{sub 2})(BO3). 2 and 3 display a new [UO{sub 5}]{sub 1{infinity}} anion topology with a basic building block of edge-sharing dimers comprised of (UO{sub 7}){sub 2} polyhedra. The A(UO{sub 2})(BO{sub 3}) (A = alkali metal) series shows a systematic structural evolution, which will be discussed in the main text. (orig.)

  17. Uranyl-specific binding at a functionalised interface: a chemophotonic fibre optic sensor platform.

    Science.gov (United States)

    Hayes, Neil W; Tremlett, Clare J; Melfi, Patricia J; Sessler, Jonathon D; Shaw, Andrew M

    2008-05-01

    Detection of radiological materials in the solution phase is restricted by conventional radiation-counting techniques owing to extreme attenuation. Chemical sensing of the resultant radiological species such as uranyl UO(2)(2+) is possible on the surface of a plastic or glass fibre optic. A dihydroxy isoamethryin complex is tethered to the fibre surface which has a large extinction coefficient (119 000 M(-1) cm(-1) at lambda = 439 nm) and changes colour upon binding UO(2)(2+). The spectral changes are greater on the surface than in solution and binding is specific to UO(2)(2+) with small interferences from Gd(3+). Monitoring the spectral response in three detector bands in the red, green and blue enable the optical power change to be measured with sensitivities of 1 mdB, allowing UO(2)(2+) to be detected confidently at 50-100 ppb levels. Real-time kinetic analysis enables discrimination between the target species and possible interferents.

  18. Chemical, mass spectrometric, spectrochemical, nuclear, and radiochemical analysis of nuclear-grade uranyl nitrate solutions

    Energy Technology Data Exchange (ETDEWEB)

    1981-01-01

    The standard covers analytical procedures to determine compliance of nuclear-grade uranyl nitrate solution to specifications. The following methods are described in detail: uranium by ferrous sulfate reduction-potassium dichromate titrimetry and by ignition gravimetry; specific gravity by pycnometry; free acid by oxalate complexation; thorium by the Arsenazo(III) (photometric) method; chromium by the diphenylcarbazide (photometric) method; molybdenum by the thiocyanate (photometric) method; halogens separation by steam distillation; fluorine by specific ion electrode; halogen distillate analysis: chloride, bromide and iodide by amperometric microtitrimetry; bromine by the fluorescein (photometric) method; sulfate sulfur by (photometric) turbidimetry; phosphorus by the molybdenum blue (photometric) method; silicon by the molybdenum blue (photometric) method; carbon by persulfate oxidation-acid titrimetry; nonvolatile impurities by spectrography; volatile impurities by rotating-disk spark spectrography; boron by emission spectrography; impurity elements by spark source mass spectrography; isotopic composition by multiple filament surface-ionization mass spectrometry; uranium-232 by alpha spectrometry; total alpha activity by direct alpha counting; fission product activity by beta and gamma counting; entrained organic matter by infrared spectrophotometry. (JMT)

  19. Oxo Ligand Substitution in a Cationic Uranyl Complex: Synergistic Interaction of an Electrophile and a Reductant.

    Science.gov (United States)

    Pedrick, Elizabeth A; Wu, Guang; Hayton, Trevor W

    2015-07-20

    Reaction of [U(VI)O2(dppmo)2(OTf)][OTf] (dppmo = Ph2P(O)CH2P(O)Ph2) with 4 equiv of Ph3SiOTf and 2 equiv of Cp2Co generates the U(IV) complex U(IV)(OTf)4(dppmo)2 (1), as a yellow-green crystalline solid in 83% yield, along with Ph3SiOSiPh3 and [Cp2Co][OTf]. This reaction proceeds via a U(IV) silyloxide intermediate, [U(IV)(OSiPh3)(dppmo)2(OTf)2][OTf] (2), which we have isolated and structurally characterized. Similarly, reaction of [U(VI)O2(TPPO)4][OTf]2 (TPPO = Ph3PO) with 6 equiv of Me3SiOTf and 2 equiv of Cp2Co generates the U(IV) complex, [Cp2Co][U(IV)(OTf)5(TPPO)2] (3), as a yellow-green crystalline solid in 76% yield, concomitant with formation of Me3SiOSiMe3, [Ph3POSiMe3][OTf], and [Cp2Co][OTf]. Complexes 1 and 3 have been fully characterized, including analysis by X-ray crystallography. The conversion of [U(VI)O2(dppmo)2(OTf)][OTf] and [U(VI)O2(TPPO)4][OTf]2 to complexes 1 and 3, respectively, represents rare examples of well-defined uranyl oxo ligand substitution.

  20. Examining the fixation kinetics of chelated and non-chelated copper and the applications to micronutrient management in semiarid alkaline soils

    Science.gov (United States)

    Udeigwe, T. K.; Eichmann, M. B.; Menkiti, M. C.; Kusi, N. Y. O.

    2016-02-01

    This study examined and compared the fixation and fixation kinetics of copper (Cu) in chelated (ethylene diamine tetraacetic acid, EDTA) and non-chelated mixed systems of micronutrients in the semiarid soils of the Southern High Plains, USA, using findings from Cu extraction studies and kinetic models. Approximately, 22 % more Cu was fixed in the non-chelated system compared to the chelated within the first 14 days with only 7 % difference between the two systems by day 90. Findings suggest a decrease in the effectiveness of chelated micronutrients over time, highlighting the significance of timing even when chelated micronutrients are used. The strengths of the relationship of change in available Cu with respect to other micronutrients (iron (Fe), manganese (Mn), and zinc (Zn)) were higher in the non-chelated system (R2: 0.68-0.94), compared to the chelated (R2: 0.42-0.81), with slopes of 0.40 (Cu-Fe), 0.31 (Cu-Mn), and 1.04 (Cu-Zn) in the non-chelated system and 0.26 (Cu-Fe), 0.22 (Cu-Mn), and 0.90 (Cu-Zn) in the chelated system. Reduction in the amount of available Cu was best described by the power function model (R2 = 0.91, SE = 0.081) in the non-chelated system and second-order model (R2 = 0.95, SE = 0.010) in the chelated system. The applications generated from this study could be used as tools for improved micronutrient management and also provide baseline data for future work in other semiarid/arid alkaline soils of the world. Findings are also more applicable to field settings, an improvement over related previous studies.

  1. [Antinuclear antibodies].

    Science.gov (United States)

    Cabiedes, Javier; Núñez-Álvarez, Carlos A

    2010-01-01

    Anti-nuclear antibodies (ANA) are immunoglobulin directed against autologous cell nuclear and cytoplasmic components. Besides the autoimmune ANA there are other ANA that can be detected in circulation, like natural and infectious ANA. Because of its high sensibility, detection of the ANA must be done by indirect immunofluorescence (IIF) as screening test and all of those positive samples are convenient to confirm its specificity by ELISA, western blot or other techniques. Positive ANA detected by IIF must be evaluated taking in to account the pattern and titer. The following recommended step is the specificity characterization (reactivity against extractable nuclear antigens [ENA], dsDNA, etc.) which is useful for the diagnosis and follow up of patients with autoimmune diseases, and by such reasoning, its detection must be performed in an orderly and reasonable way using guides or strategies focused to the good use and interpretation of the autoantibodies. The objective of this review is to present a compilation of the literature and our experience in the detection and study of the ANA.

  2. Alkali-metal ion coordination in uranyl(VI) poly-peroxo complexes in solution, inorganic analogues to crown-ethers. Part 2. Complex formation in the tetramethyl ammonium-, Li(+)-, Na(+)- and K(+)-uranyl(VI)-peroxide-carbonate systems.

    Science.gov (United States)

    Zanonato, Pier Luigi; Szabó, Zoltán; Vallet, Valerie; Di Bernardo, Plinio; Grenthe, Ingmar

    2015-10-01

    The constitution and equilibrium constants of ternary uranyl(vi) peroxide carbonate complexes [(UO2)p(O2)q(CO3)r](2(p-q-r)) have been determined at 0 °C in 0.50 M MNO3, M = Li, K, and TMA (tetramethyl ammonium), ionic media using potentiometric and spectrophotometric data; (17)O NMR data were used to determine the number of complexes present. The formation of cyclic oligomers, "[(UO2)(O2)(CO3)]n", n = 4, 5, 6, with different stoichiometries depending on the ionic medium used, suggests that Li(+), Na(+), K(+) and TMA ions act as templates for the formation of uranyl peroxide rings where the uranyl-units are linked by μ-η(2)-η(2) bridged peroxide-ions. The templating effect is due to the coordination of the M(+)-ions to the uranyl oxygen atoms, where the coordination of Li(+) results in the formation of Li[(UO2)(O2)(CO3)]4(7-), Na(+) and K(+) in the formation of Na/K[(UO2)(O2)(CO3)]5(9-) complexes, while the large tetramethyl ammonium ion promotes the formation of two oligomers, TMA[(UO2)(O2)(CO3)]5(9-) and TMA[(UO2)(O2)(CO3)]6(11-). The NMR spectra demonstrate that the coordination of Na(+) in the five- and six-membered oligomers is significantly stronger than that of TMA(+); these observations suggest that the templating effect is similar to the one observed in the synthesis of crown-ethers. The NMR experiments also demonstrate that the exchange between TMA[(UO2)(O2)(CO3)]5(9-) and TMA[(UO2)(O2)(CO3)]6(11-) is slow on the (17)O chemical shift time-scale, while the exchange between TMA[(UO2)(O2)(CO3)]6(11-) and Na[(UO2)(O2)(CO3)]6(11-) is fast. There was no indication of the presence of large clusters of the type identified by Burns and Nyman (M. Nyman and P. C. Burns, Chem. Soc. Rev., 2012, 41, 7314-7367) and possible reasons for this and the implications for the synthesis of large clusters are briefly discussed.

  3. An integrated study of uranyl mineral dissolution processes. Etch pit formation, effects of cations in solution, and secondary precipitation

    Energy Technology Data Exchange (ETDEWEB)

    Schindler, M. [Laurentian Univ., Sudbury, ON (Canada). Dept. of Earth Sciences; Hawthorne, F.C. [Manitoba Univ., Winnipeg, MB (Canada). Dept. of Geological Sciences; Mandaliev, P. [Eidgenoessische Technische Hochschule (ETH), Zurich (Switzerland). Dept. of Environmental Sciences; Burns, P.C.; Maurice, P.A. [Notre Dame Univ., IN (United States). Dept. of Civil Engineering and Geological Sciences

    2011-07-01

    Understanding the mechanism(s) of uranium-mineral dissolution is crucial for predictive modeling of U mobility in the subsurface. In order to understand how pH and type of cation in solution may affect dissolution, experiments were performed on mainly single crystals of curite, Pb{sup 2+}{sub 3}(H{sub 2}O){sub 2}[(UO{sub 2}){sub 4}O{sub 4}(OH){sub 3}]{sub 2}, becquerelite, Ca(H{sub 2}O){sub 8}[(UO{sub 2}){sub 6}O{sub 4}(OH){sub 6}], billietite, Ba(H{sub 2}O){sub 7}[(UO{sub 2}){sub 6}O{sub 4}(OH){sub 6}], fourmarierite Pb{sup 2+}{sub 1-x}(H{sub 2}O){sub 4}[(UO{sub 2}){sub 4}O{sub 3-2x}(OH){sub 4+2x}] (x= 0.00-0.50), uranophane, Ca(H{sub 2}O){sub 5}[(UO{sub 2})(SiO{sub 3}OH)]{sub 2}, zippeite, K{sub 3}(H{sub 2}O){sub 3}[(UO{sub 2}){sub 4}(SO{sub 4}){sub 2}O{sub 3}(OH)], and Na-substituted metaschoepite, Na{sub 1-x}[(UO{sub 2}){sub 4}O{sub 2-x}(OH){sub 5+x}] (H{sub 2}O){sub n}. Solutions included: deionized water; aqueous HCl solutions at pH 3.5 and 2; 0.5 mol L{sup -1} Pb(II)-, Ba-, Sr-, Ca-, Mg-, HCl solutions at pH 2; 1.0 mol L{sup -1} Na- and K-HCl solutions at pH 2; and a 0.1 mol L{sup -1} Na{sub 2}CO{sub 3} solution at pH 10.5. Uranyl mineral basal surface microtopography, micromorphology, and composition were examined prior to, and after dissolution experiments on micrometer scale specimens using atomic force microscopy, scanning electron microscopy, and X-ray photoelectron spectroscopy. Evolution of etch pit depth at different pH values and experimental durations can be explained using a stepwave dissolution model. Effects of the cation in solution on etch pit symmetry and morphology can be explained using an adsorption model involving specific surface sites. Surface precipitation of the following phases was observed: (a) a highly-hydrated uranyl-hydroxy-hydrate in ultrapure water (on all minerals), (b) a Na-uranyl-hydroxy-hydrate in Na{sub 2}CO{sub 3} solution of pH 10.5 (on uranyl-hydroxy-hydrate minerals), (c) a Na-uranyl-carbonate on zippeite, (d) Ba- and

  4. Determination of formation constants of uranyl(VI complexes with a hydrophilic SO3-Ph-BTP ligand, using liquid-liquid extraction

    Directory of Open Access Journals (Sweden)

    Steczek Lukasz

    2015-12-01

    Full Text Available Complex formation between uranyl ion, UO22+, and a hydrophilic anionic form of SO3-Ph-BTP4- ligand, L4-, in water was studied by liquid-liquid extraction experiments performed over a range of the ligand and HNO3 concentrations in the aqueous phase, at a constant concentration of nitrate anions at 25°C . The competition for UO22+ ions between the lipophilic TODGA extractant and the hydrophilic L4- ligand leads to the decrease in the uranyl distribution ratios, D, with an increasing L4- concentration. The model of the solvent extraction process used accounts - apart from uranyl complexation by TODGA and SO3-Ph-BTP4- - also for uranyl complexation by nitrates and for the decrease in the concentration of the free L4- ligand in the aqueous phase, due to its protonation, bonding in the uranyl complex and the distribution between the two liquid phases. The unusually strong dependence of the D values on the acidity, found in the experiment, could hardly be explained as due to L4- protonation merely. Three hypotheses were experimentally tested, striving to interpret the data in terms of additional extraction to the organic phase of ion associates of protonated TODGA cation with either partly protonated anionic L4- ligands or anionic UO22+ complexes with NO3 - or L4-. None of them has been confirmed. The analysis of the results, based on the formal correction of free ligand concentrations, points to the formation of 1 : 1 and 1 : 2 uranyl - SO3-Ph-BTP complexes in the aqueous phase. The conditional formation constant of the 1:1 complex has been determined, logßL,1 = 2.95 ± 0.15.

  5. MULTIDENTATE TEREPHTHALAMIDATE AND HYDROXYPYRIDONATE LIGANDS: TOWARDS NEW ORALLY ACTIVE CHELATORS

    Energy Technology Data Exchange (ETDEWEB)

    Abergel, Rebecca J.; Raymond, Kenneth N.

    2011-07-13

    The limitations of current therapies for the treatment of iron overload or radioisotope contamination have stimulated efforts to develop new orally bioavailable iron and actinide chelators. Siderophore-inspired tetradentate, hexadentate and octadentate terephthalamidate and hydroxypyridonate ligands were evaluated in vivo as selective and efficacious iron or actinide chelating agents, with several metal loading and ligand assessment procedures, using {sup 59}Fe, {sup 238}Pu, and {sup 241}Am as radioactive tracers. The compounds presented in this study were compared to commercially available therapeutic sequestering agents [deferoxamine (DFO) for iron and diethylenetriaminepentaacetic acid (DPTA) for actinides] and are unrivaled in terms of affinity, selectivity and decorporation efficacy, which attests to the fact that high metal affinity may overcome the low bioavailability properties commonly associated to multidenticity.

  6. Lanthanides caged by the organic chelates; structural properties.

    Science.gov (United States)

    Smentek, Lidia

    2011-04-13

    The structure, in particular symmetry, geometry and morphology of organic chelates coordinated with the lanthanide ions are analyzed in the present review. This is the first part of a complete presentation of a theoretical description of the properties of systems, which are widely used in technology, but most of all, in molecular biology and medicine. The discussion is focused on the symmetry and geometry of the cages, since these features play a dominant role in the spectroscopic activity of the lanthanides caged by organic chelates. At the same time, the spectroscopic properties require more formal presentation in the language of Racah algebra, and deserve a separate analysis. In addition to the parent systems of DOTA, DOTP, EDTMP and CDTMP presented here, their modifications by various antennas are analyzed. The conclusions that have a strong impact upon the theory of the energy transfer and the sensitized luminescence of these systems are based on the results of numerical density functional theory calculations.

  7. Removal of cadmium from fish sauce using chelate resin.

    Science.gov (United States)

    Sasaki, Tetsuya; Araki, Ryohei; Michihata, Toshihide; Kozawa, Miyuki; Tokuda, Koji; Koyanagi, Takashi; Enomoto, Toshiki

    2015-04-15

    Fish sauce that is prepared from squid organs contains cadmium (Cd), which may be present at hazardous concentrations. Cd molecules are predominantly protein bound in freshly manufactured fish sauce, but are present in a liberated form in air-exposed fish sauce. In the present study, we developed a new method for removing both Cd forms from fish sauce using chelate resin and a previously reported tannin treatment. Sixteen-fold decreases in Cd concentrations were observed (0.78-0.05 mg/100 mL) following the removal of liberated Cd using chelate resin treatment, and the removal of protein-bound Cd using tannin treatment. Major nutritional components of fish sauce were maintained, including free amino acids and peptides, and angiotensin I-converting enzyme inhibitory and antioxidant activities.

  8. Neurodegenerative diseases and therapeutic strategies using iron chelators.

    Science.gov (United States)

    Ward, Roberta J; Dexter, David T; Crichton, Robert R

    2015-01-01

    This review will summarise the current state of our knowledge concerning the involvement of iron in various neurological diseases and the potential of therapy with iron chelators to retard the progression of the disease. We first discuss briefly the role of metal ions in brain function before outlining the way by which transition metal ions, such as iron and copper, can initiate neurodegeneration through the generation of reactive oxygen and nitrogen species. This results in protein misfolding, amyloid production and formation of insoluble protein aggregates which are contained within inclusion bodies. This will activate microglia leading to neuroinflammation. Neuroinflammation plays an important role in the progression of the neurodegenerative diseases, with activated microglia releasing pro-inflammatory cytokines leading to cellular cell loss. The evidence for metal involvement in Parkinson's and Alzheimer's disease as well as Friedreich's ataxia and multiple sclerosis will be presented. Preliminary results from trials of iron chelation therapy in these neurodegenerative diseases will be reviewed.

  9. Highly Enriched Uranyl Nitrate in Annular Tanks with Concrete Reflection: 1 x 3 Line Array of Nested Pairs of Tanks

    Energy Technology Data Exchange (ETDEWEB)

    James Cleaver; John D. Bess; Nathan Devine; Fitz Trumble

    2009-09-01

    A series of seven experiments were performed at the Rocky Flats Critical Mass Laboratory beginning in August, 1980 (References 1 and 2). Highly enriched uranyl nitrate solution was introduced into a 1-3 linear array of nested stainless steel annular tanks. The tanks were inside a concrete enclosure, with various moderator and absorber materials placed inside and/or between the tanks. These moderators and absorbers included boron-free concrete, borated concrete, borated plaster, and cadmium. Two configurations included placing bottles of highly enriched uranyl nitrate between tanks externally. Another experiment involved nested hemispheres of highly enriched uranium placed between tanks externally. These three configurations are not evaluated in this report. The experiments evaluated here are part of a series of experiments, one set of which is evaluated in HEU-SOL-THERM-033. The experiments in this and HEU-SOL-THERM-033 were performed similarly. They took place in the same room and used the same tanks, some of the same moderators and absorbers, some of the same reflector panels, and uranyl nitrate solution from the same location. There are probably additional similarities that existed that are not identified here. Thus, many of the descriptions in this report are either the same or similar to those in the HEU-SOL-THERM-033 report. Seventeen configurations (sixteen of which were critical) were performed during seven experiments; six of those experiments are evaluated here with thirteen configurations. Two configurations were identical, except for solution height, and were conducted to test repeatability. The solution heights were averaged and the two were evaluated as one configuration, which gives a total of twelve evaluated configurations. One of the seventeen configurations was subcritical. Of the twelve critical configurations evaluated, nine were judged as acceptable as benchmarks.

  10. Selection of antibodies from synthetic antibody libraries.

    Science.gov (United States)

    Harel Inbar, Noa; Benhar, Itai

    2012-10-15

    More than 2 dozen years had passed since the field of antibody engineering was established, with the first reports of bacterial [1-3] and mammalian cells [4] expression of recombinant antibody fragments, and in that time a lot of effort was dedicated to the development of efficient technological means, intended to assist in the creation of therapeutic monoclonal antibodies (mAbs). Research focus was given to two intertwined technological aspects: the selection platform and the recombinant antibody repertoires. In accordance with these areas of interest, it is the goal of this chapter to describe the various selection tools and antibody libraries existing, with emphasis on the later, and their applications. This chapter gives a far from exhaustive, subjective "historic account" of the field, describing the selection platforms, the different formats of antibody repertoires and the applications of both for selecting recombinant antibodies. Several excellent books provide detailed protocols for constructing antibody libraries and selecting antibodies from those libraries [5-13]. Such books may guide a newcomer to the field in the fine details of antibody engineering. We would like to offer advice to the novice: although seemingly simple, effective library construction and antibody isolation provide best benefits in the hands of professionals. It is an art as much as it is science.

  11. Flue gas desulfurization/denitrification using metal-chelate additives

    Science.gov (United States)

    Harkness, John B. L.; Doctor, Richard D.; Wingender, Ronald J.

    1986-01-01

    A method of simultaneously removing SO.sub.2 and NO from oxygen-containing flue gases resulting from the combustion of carbonaceous material by contacting the flue gas with an aqueous scrubber solution containing an aqueous sulfur dioxide sorbent and an active metal chelating agent which promotes a reaction between dissolved SO.sub.2 and dissolved NO to form hydroxylamine N-sulfonates. The hydroxylamine sulfonates are then separated from the scrubber solution which is recycled.

  12. Mineral Levels in Thalassaemia Major Patients Using Different Iron Chelators.

    Science.gov (United States)

    Genc, Gizem Esra; Ozturk, Zeynep; Gumuslu, Saadet; Kupesiz, Alphan

    2016-03-01

    The goal of the present study was to determine the levels of minerals in chronically transfused thalassaemic patients living in Antalya, Turkey and to determine mineral levels in groups using different iron chelators. Three iron chelators deferoxamine, deferiprone and deferasirox have been used to remove iron from patients' tissues. There were contradictory results in the literature about minerals including selenium, zinc, copper, and magnesium in thalassaemia major patients. Blood samples from the 60 thalassaemia major patients (the deferoxamine group, n = 19; the deferiprone group, n = 20 and the deferasirox group, n = 21) and the controls (n = 20) were collected. Levels of selenium, zinc, copper, magnesium, and iron were measured, and all of them except iron showed no significant difference between the controls and the patients regardless of chelator type. Serum copper levels in the deferasirox group were lower than those in the control and deferoxamine groups, and serum magnesium levels in the deferasirox group were higher than those in the control, deferoxamine and deferiprone groups. Iron levels in the patient groups were higher than those in the control group, and iron levels showed a significant correlation with selenium and magnesium levels. Different values of minerals in thalassaemia major patients may be the result of different dietary intake, chelator type, or regional differences in where patients live. That is why minerals may be measured in thalassaemia major patients at intervals, and deficient minerals should be replaced. Being careful about levels of copper and magnesium in thalassaemia major patients using deferasirox seems to be beneficial.

  13. Decontamination of process equipment using recyclable chelating solvent

    Energy Technology Data Exchange (ETDEWEB)

    Jevec, J.; Lenore, C.; Ulbricht, S. [Babcock & Wilcox, Co., R& DD, Alliance, OH (United States)

    1995-10-01

    The Department of Energy (DOE) is now faced with the task of meeting decontamination and decommissioning obligations at numerous facilities by the year 2019. Due to the tremendous volume of material involved, innovative decontamination technologies are being sought that can reduce the volumes of contaminated waste materials and secondary wastes requiring disposal. This report describes the results of the performance testing of chelates and solvents for the dissolution of uranium.

  14. Mechanism of rhythmic contractions induced by uranyl ion in the ileal longitudinal muscle of guinea-pig

    Energy Technology Data Exchange (ETDEWEB)

    Wenmei Fu; Shoeiyn Linshiau

    1985-07-17

    The uranyl ion (UO2S ) produces rhythmic contractions of the longitudinal muscle of the ileum, similar to those induced by repetitive transmural stimulation. Hexamethonium inhibited the action of UO2S , indicating a preganglionic site of action of UO2S and interneurons possibly being involved in the ACh-releasing effect of UO2S . In addition, the action of UO2S was enhanced by physostigmine but antagonized by atropine, ATP, adrenaline and morphine suggesting multiple sites of action of UO2S . The effects of BaS were studied simultaneously in order to compare them with those of UO2S . (Auth.). 25 refs.; 4 figs.

  15. Chemical controls on uranyl citrate speciation and the self-assembly of nanoscale macrocycles and sandwich complexes in aqueous solutions.

    Science.gov (United States)

    Basile, M; Unruh, D K; Gojdas, K; Flores, E; Streicher, L; Forbes, T Z

    2015-03-28

    Uranyl citrate forms trimeric species at pH > 5.5, but exact structural characteristics of these important oligomers have not previously been reported. Crystallization and structural characterization of the trimers suggests the self-assembly of the 3 : 3 and 3 : 2 U : Cit complexes into larger sandwich and macrocyclic molecules. Raman spectroscopy and ESI-MS have been utilized to investigate the relative abundance of these species in solution under varying pH and citrate concentrations. Additional dynamic light scattering experiments indicate that self-assembly of the larger molecules does occur in aqueous solution.

  16. Copper and Zinc Chelation as a Treatment of Alzheimer's Disease

    Science.gov (United States)

    Hodak, Miroslav; Bernholc, Jerry

    2014-03-01

    Alzheimer's disease (AD) is a neurodegenerative disorder affecting millions of people in the U.S. The cause of the disease remains unknown, but amyloid- β (A β), a short peptide, is considered causal its pathogenesis. At cellular level, AD is characterized by deposits mainly composed of A β that also contain elevated levels of transition metals ions. Targeting metals is a promising new strategy for AD treatment, which uses moderately strong metal chelators to sequester them from A β or the environment. PBT2 is a chelating compound that has been the most promising in clinical trials. In our work, we use computer simulations to investigate complexes of a close analog of PBT2 with Cu2+ and Zn2+ ions. The calculations employ KS/FD DFT method, which combines Kohn-Sham DFT with the frozen-density DFT to achieve efficient description of explicit solvent beyond the first solvation shell. Our work is based on recent experiments and examines both 1:1 and 2:1 chelator-metal stochiometries detected experimentally. The results show that copper attaches more strongly than zinc, find that 1:1 complexes involve water in the first coordination shell and determine which one of several possible 2:1 geometries is the most preferable.

  17. Elucidating Interactions between DMSO and Chelate-Based Ionic Liquids.

    Science.gov (United States)

    Chen, Hang; Wang, Xinyu; Yao, Jia; Chen, Kexian; Guo, Yan; Zhang, Pengfei; Li, Haoran

    2015-12-21

    The C-D bond stretching vibrations of deuterated dimethyl sulfoxide ([D6 ]DMSO) and the C2 -H bond stretching vibrations of 1,1,1,5,5,5-hexafluoropentane-2,4-dione (hfac) ligand in anion are chosen as probes to elucidate the solvent-solute interaction between chelate-based ionic liquids (ILs) and DMSO by vibrational spectroscopic studies. The indirect effect from the interaction of the adjacent S=O functional group of DMSO with the cation [C10 mim](+) and anion [Mn(hfac)3 ](-) of the ILs leads to the blue-shift of the C-D stretching vibrations of DMSO. The C2 -H bond stretching vibrations in hfac ligand is closely related to the ionic hydrogen bond strength between the cation and anion of chelate-based ILs. EPR studies reveal that the crystal field of the central metal is kept when the chelate-based ILs are in different microstructure environment in the solution.

  18. Hydroxyurea could be a good clinically relevant iron chelator.

    Directory of Open Access Journals (Sweden)

    Khushnooma Italia

    Full Text Available Our previous study showed a reduction in serum ferritin of β-thalassemia patients on hydroxyurea therapy. Here we aimed to evaluate the efficacy of hydroxyurea alone and in combination with most widely used iron chelators like deferiprone and deferasirox for reducing iron from experimentally iron overloaded mice. 70 BALB/c mice received intraperitonial injections of iron-sucrose. The mice were then divided into 8 groups and were orally given hydroxyurea, deferiprone or deferasirox alone and their combinations for 4 months. CBC, serum-ferritin, TBARS, sTfr and hepcidin were evaluated before and after iron overload and subsequently after 4 months of drug therapy. All animals were then killed. Iron staining of the heart and liver tissue was done using Perl's Prussian Blue stain. Dry weight of iron in the heart and liver was determined by atomic absorption spectrometry. Increased serum-ferritin, TBARS, hepcidin and dry weight of iron in the liver and heart showed a significant reduction in groups treated with iron chelators with maximum reduction in the group treated with a combination of deferiprone, deferasirox and hydroxyurea. Thus hydroxyurea proves its role in reducing iron from iron overloaded mice. The iron chelating effect of these drugs can also be increased if given in combination.

  19. Examining the fixation kinetics of chelated and non-chelated copper micronutrient and the applications to micronutrient management in semi-arid alkaline soils

    Science.gov (United States)

    Udeigwe, T. K.; Eichmann, M. B.; Menkiti, M. C.

    2015-10-01

    The relationship between the deficiency of a nutrient in plants and its total concentration in the soil is complex. This study examined and compared the fixation and fixation kinetics of copper (Cu) in chelated (Ethylene diamine tetraacetic acid, EDTA) and non-chelated mixed systems of micronutrients in the semi-arid soils of the Southern High Plains, US using findings from Cu extraction studies and kinetic models. Approximately, 22 % more Cu was fixed in the non-chelated system within the first 14 days with only 7 % difference between the two systems by day 90. Findings suggest a decrease in the effectiveness of chelated micronutrient over time, highlighting the significance of timing even when chelated micronutrients are applied. The strengths of the relationship of change in available Cu with respect to other micronutrients [iron (Fe), manganese (Mn), and zinc (Zn)] were higher in the non-chelated system (R2: 0.68-0.94), compared to the chelated (R2: 0.42-0.81) with slopes of 0.40 (Cu-Fe), 0.31 (Cu-Mn), and 1.04 (Cu-Zn) in the non-chelated system and 0.26 (Cu-Fe), 0.22 (Cu-Mn), and 0.90 (Cu-Zn) in the chelated. Reduction in the amount of available Cu was best described by the power function model (R2 = 0.91, SE = 0.081) in the non-chelated system and second order model (R2 = 0.95, SE = 0.010) in the chelated system. The applications generated from this study could be used as tools for improved micronutrient management and also provide baseline data for future work in other semi-arid/arid alkaline soils of the world. Findings are also more applicable to field settings, an improvement over related previous studies.

  20. Structural study of the uranyl and rare earth complexation functionalized by the CMPO; Etude structurale de la complexation de l'uranyle et des ions lanthanides par des calixarenes fonctionnalises par le CMPO

    Energy Technology Data Exchange (ETDEWEB)

    Cherfa, S

    1998-12-10

    In view of reducing the volume of nuclear waste solutions, a possible way is to extract simultaneously actinide and lanthanide ions prior to their ulterior separation.. Historically, the two extractant families used for nuclear waste reprocessing are the phosphine oxides and the CMPO (Carbamoyl Methyl Phosphine Oxide). For a better understanding of the complexes formed during extraction, we undertook structural studies of the complexes formed between uranyl and lanthanide (III) ions and the two classes of ligands cited above. These studies have been performed by X-ray diffraction on single crystals. Recently, a new type of extractants of lanthanide (III) and actinide (III) ions has been developed. When the Organic macrocycle called calixarene (an oligomeric compound resulting from the poly-condensation of phenolic units) is functionalized by a CMPO ligand, the extracting power, in terms of yield and selectivity towards lightest lanthanides, is greatly enhanced compared to the one measured for the single CMPO. Our X-ray diffraction studies allowed us to characterise, in terms of stoichiometry and monodentate or bidentate coordination mode of the CMPO functions, the complexes of calix[4]arene-CMPO (with four phenolic units) with lanthanide nitrates and uranyl. These different steps of characterisation enabled us to determine the correlation between the structures of the complexes and both selectivity and exacerbation of the extracting power measured in the liquid phase. (author)

  1. Chelation therapy in Wilson's disease: from D-penicillamine to the design of selective bioinspired intracellular Cu(I) chelators.

    Science.gov (United States)

    Delangle, Pascale; Mintz, Elisabeth

    2012-06-01

    Wilson's disease is an orphan disease due to copper homeostasis dysfunction. Mutations of the ATP7B gene induces an impaired functioning of a Cu-ATPase, impaired Cu detoxification in the liver and copper overload in the body. Indeed, even though copper is an essential element, which is used as cofactor by many enzymes playing vital roles, it becomes toxic when in excess as it promotes cytotoxic reactions leading to oxidative stress. In this perspective, human copper homeostasis is first described in order to explain the mechanisms promoting copper overload in Wilson's disease. We will see that the liver is the main organ for copper distribution and detoxification in the body. Nowadays this disease is treated life-long by systemic chelation therapy, which is not satisfactory in many cases. Therefore the design of more selective and efficient drugs is of great interest. A strategy to design more specific chelators to treat localized copper accumulation in the liver will then be presented. In particular we will show how bioinorganic chemistry may help in the design of such novel chelators by taking inspiration from the biological copper cell transporters.

  2. Crystal chemistry and application development of uranyl extended structure and nanoscale materials and actinyl ion-substituted mineral phases

    Science.gov (United States)

    Wylie, Ernest M.

    The worldwide use of nuclear energy presents both significant advantages and challenges for society. Actinide research seeks to address these challenges and drive advancement in the fields of nuclear science and engineering. Here, key aspects of the fuel cycle are examined from both a fundamental and an applications-based perspective. Hydrothermal, ionothermal, room-temperature evaporation, and liquid diffusion synthesis techniques and single-crystal X-ray diffraction were used to study the structures of 18 uranyl compounds and six actinyl-doped mineral phases. These compounds represent a diverse group ranging from unique molecular clusters to novel and known extended structures isolated from aqueous and ionic liquid media. Ultrafiltration techniques were utilized to separate uranyl peroxide nanoclusters from complex aqueous solutions. Inductively coupled plasma optical emission spectroscopy and mass spectrometry were used to quantify elemental distributions in the feed and permeate solutions while Raman spectroscopy, small-angle X-ray scattering, and electrospray ionization mass spectrometry were used to define the characteristics of the cluster species across a range different solution conditions.

  3. Effects of a low-radiotoxicity uranium salt (uranyl acetate) on biochemical and hematological parameters of the catfish, Clarias gariepinus

    Science.gov (United States)

    Al-Ghanim, Khalid A.; Ahmad, Zubair; Al-Kahem Al-Balawi, Hmoud F.; Al-Misned, Fahad; Maboob, Shahid; Suliman, El-Amin M.

    2016-01-01

    Specimens of Clarias gariepinus were treated with lethal (70, 75, 80, 85, 90, and 95 mg/L) and sub-lethal concentrations (8, 12 and 16 mg/L) of uranyl acetate, a low-radiotoxicity uranium salt. The LC 50 value was registered as 81.45 mg/L. The protein and glycogen concentrations in liver and muscles were decreased in the fish exposed to sub-lethal concentrations. The red blood cell (RBC) and white blood cell (WBC) counts, haemoglobin (Hb) concentration and haematocrit (Hct) values were decreased. Different blood indices like mean corpuscular volume (MCV), mean corpuscular haemoglobin (MCH) and mean corpuscular haemoglobin concentration (MCHC) were negatively affected. Level of plasma glucose was elevated whereas protein was decreased. The level of calcium concentration (Ca) was declined in the blood of exposed fish whereas magnesium (Mg) remains unchanged. The activity level of glutamic-oxaloacetic transaminase (GOT) and glutamic-pyruvic transaminase (GPT) was elevated in exposed fish. These effects were more pronounced in the last period of exposure and in higher concentrations. Results of the present study indicate that uranyl acetate has adverse effects on Clarias gariepinus and causes changes in the biochemical and hematological parameters of the fish.

  4. Uranyl ion extraction with conventional PUREX/TRUEX ligands assessed by electroanalytical chemistry at micro liquid/liquid interfaces.

    Science.gov (United States)

    Stockmann, Tom J; Ding, Zhifeng

    2011-10-01

    The facilitated ion transfer (FIT) of uranyl or dioxouranium (UO(2)(2+)) was studied electrochemically using a micro interface between two immiscible electrolytic solutions (micro-ITIES) in order to evaluate the complexation stoichiometry and complexation constants (β) of two widely used ligands in spent fuel reprocessing: tributylphosphate (TBP) and octyl(phenyl)-N,N-diisobutylcarbamoylmethyl-phosphine oxide (CMPO). For the first time, discrete interfacial complexation reaction steps of varying uranyl to the two ligands ratios were resolved using the micro-ITIES hosted at the tip of a 25 μm diameter glass capillary. Two stoichiometries for UO(2)NO(3)TBP(n)(+) were determined including n = 3 and 4 with β values of 3.2 × 10(11) and 3.9 × 10(13), respectively. Subsequently, three distinct complexation reactions of CMPO with UO(2)(2+) were discovered corresponding to UO(2)NO(3)CMPO(2)(+), UO(2)NO(3)CMPO(3)(+), and UO(2)CMPO(5)(2+) whose respective complexation constants were determined to be 8.0 × 10(11), 8.8 × 10(14), and 6.5 × 10(32). The participation of nitrate anions in these complexation reactions is also discussed.

  5. Standard test method for gamma energy emission from fission products in uranium hexafluoride and uranyl nitrate solution

    CERN Document Server

    American Society for Testing and Materials. Philadelphia

    2005-01-01

    1.1 This test method covers the measurement of gamma energy emitted from fission products in uranium hexafluoride (UF6) and uranyl nitrate solution. It is intended to provide a method for demonstrating compliance with UF6 specifications C 787 and C 996 and uranyl nitrate specification C 788. 1.2 The lower limit of detection is 5000 MeV Bq/kg (MeV/kg per second) of uranium and is the square root of the sum of the squares of the individual reporting limits of the nuclides to be measured. The limit of detection was determined on a pure, aged natural uranium (ANU) solution. The value is dependent upon detector efficiency and background. 1.3 The nuclides to be measured are106Ru/ 106Rh, 103Ru,137Cs, 144Ce, 144Pr, 141Ce, 95Zr, 95Nb, and 125Sb. Other gamma energy-emitting fission nuclides present in the spectrum at detectable levels should be identified and quantified as required by the data quality objectives. 1.4 This standard does not purport to address all of the safety concerns, if any, associated with its us...

  6. Characterizing the interaction between uranyl ion and fulvic acid using regional integration analysis (RIA) and fluorescence quenching.

    Science.gov (United States)

    Zhu, Bingqi; Ryan, David K

    2016-03-01

    The development of chemometric methods has substantially improved the quantitative usefulness of the fluorescence excitation-emission matrix (EEM) in the analysis of dissolved organic matter (DOM). In this study, Regional Integration Analysis (RIA) was used to quantitatively interpret EEMs and assess fluorescence quenching behavior in order to study the binding between uranyl ion and fulvic acid. Three fulvic acids including soil fulvic acid (SFA), Oyster River fulvic acid (ORFA) and Suwannee River fulvic acid (SRFA) were used and investigated by the spectroscopic techniques. The EEM spectra obtained were divided into five regions according to fluorescence structural features and two distinct peaks were observed in region III and region V. Fluorescence quenching analysis was conducted for these two regions with the stability constants, ligand concentrations and residual fluorescence values calculated using the Ryan-Weber model. Results indicated a relatively strong binding ability between uranyl ion and fulvic acid samples at low pH (log K value varies from 4.11 to 4.67 at pH 3.50). Fluorophores in region III showed a higher binding ability with fewer binding sites than in region V. Stability constants followed the order, SFA > ORFA > SRFA, while ligand concentrations followed the reverse order, SRFA > ORFA > SFA. A comparison between RIA and Parallel Factor Analysis (PARAFAC) data treatment methods was also performed and good agreement between these two methods (less than 4% difference in log K values) demonstrates the reliability of the RIA method in this study.

  7. Ligand size dependence of U-N and U-O bond character in a series of uranyl hexaphyrin complexes: quantum chemical simulation and density based analysis.

    Science.gov (United States)

    Di Pietro, Poppy; Kerridge, Andrew

    2017-03-02

    A series of uranyl complexes with hexaphyrin ligands are investigated at the density functional level of theory and analysed using a variety of density-based techniques. A relationship is identified between the size of the ligand and the stability of the complex, controlled by the presence of meso-carbon centres in the porphyrin ring. The complex with the smallest ligand, cyclo[6]pyrrole, is found to have enhanced covalent character in equatorial U-N bonds as defined by the quantum theory of atoms in molecules (QTAIM), as well as enhanced stability, compared to the larger complexes. QTAIM data are supported by electron density difference distributions, integrated electronic properties and analysis of the reduced density gradient (RDG), which all show unambiguous evidence of electron sharing in all U-N bonds. In all complexes, a weakening of the covalent axial U-Oyl interaction in comparison to free uranyl is found, with evidence for a separation of electronic charge resulting in a more ionic interaction. A relationship between covalent character in the U-N bonds and the magnitude of uranyl charge redistribution is identified, where the greater the covalent character of the U-N interaction, the more ionic the U-Oyl interaction appears. The complex with the largest ligand, hexaphyrin(1.1.1.1.1.1), is found to have additional interactions with the uranyl oxygen centres, perturbing the U-Oyl interaction.

  8. Behavior of mercury, lead, cesium, and uranyl ions on four SRS soils

    Energy Technology Data Exchange (ETDEWEB)

    Bibler, J.P.; Marson, D.B.

    1992-03-20

    Samples of four Savannah River Site (SRS) soils were tested for sorption behavior with Hg[sup 2+], Pb[sup 2+], UO[sub 2][sup 2+], and Cs[sup +] ions. The purpose of the study was to determine the selectivity of the different soils for these ions alone and in the presence of the competing cations, H[sup +] and Ca[sup 2+]. Distribution constants, Kd's, for the test ions in various solutions have been determined for the four soils. In general, sorption by all of the soils appeared to be more complex than a simple ion exchange or adsorption process. In particular, the presence of organic matter in soil increased the capacity of the soil due to its chelating ability. Similar soils did not react similarly toward each metal cation.

  9. Behavior of mercury, lead, cesium, and uranyl ions on four SRS soils

    Energy Technology Data Exchange (ETDEWEB)

    Bibler, J.P.; Marson, D.B.

    1992-03-20

    Samples of four Savannah River Site (SRS) soils were tested for sorption behavior with Hg{sup 2+}, Pb{sup 2+}, UO{sub 2}{sup 2+}, and Cs{sup +} ions. The purpose of the study was to determine the selectivity of the different soils for these ions alone and in the presence of the competing cations, H{sup +} and Ca{sup 2+}. Distribution constants, Kd`s, for the test ions in various solutions have been determined for the four soils. In general, sorption by all of the soils appeared to be more complex than a simple ion exchange or adsorption process. In particular, the presence of organic matter in soil increased the capacity of the soil due to its chelating ability. Similar soils did not react similarly toward each metal cation.

  10. A Review on Iron Chelators in Treatment of Iron Overload Syndromes

    Science.gov (United States)

    Mobarra, Naser; Shanaki, Mehrnoosh; Ehteram, Hassan; Nasiri, Hajar; Sahmani, Mehdi; Saeidi, Mohsen; Goudarzi, Mehdi; Pourkarim, Hoda; Azad, Mehdi

    2016-01-01

    Iron chelation therapy is used to reduce iron overload development due to its deposition in various organs such as liver and heart after regular transfusion. In this review, different iron chelators implicated in treatment of iron overload in various clinical conditions have been evaluated using more up-to-date studies focusing on these therapeutic agents. Deferoxamine, Deferiprone and Deferasirox are the most important specific US FDA-approved iron chelators. Each of these chelators has their own advantages and disadvantages, various target diseases, levels of deposited iron and clinical symptoms of the afflicted patients which may affect their selection as the best modality. Taken together, in many clinical disorders, choosing a standard chelator does not have an accurate index which requires further clarifications. The aim of this review is to introduce and compare the different iron chelators regarding their advantages and disadvantages, usage dose and specific applications. PMID:27928480

  11. Preparation of Polysulfone-supported Phosphoramidic Acid Type Chelate Membrane and Its Sorption Properties for Ag+

    Institute of Scientific and Technical Information of China (English)

    WANG Bing; CUI Yong-fang; DU Qi-yun; PEI Guang-ling

    2002-01-01

    A blending chelate filter membrane with high chelate capacity for Ag+ has been prepared by blending of phosphoramidic acid resin and polysulfone. The major parameters influencing structure of the chelate filter membranes such as the blending ratio, phosphoramidic acid resin grain size and temperature of casting solution have been studied. The relationship among the chelate amount of Ag+, pH value, Ag+ concentration and phosphoramidic acid resin grain diameter were examined. The chelate filter membrane had a capacity of1438μg/cm2 for Ag+ under appropriate conditions.Sorption isotherm of Ag + could be expressed with the Freundlich sorption model. The dynamic chelate experiments proved that the sorption and desorption of membranes could be realized simultaneously for Ag+.

  12. CCCCC pentadentate chelates with planar Möbius aromaticity and unique properties

    Science.gov (United States)

    Zhu, Congqing; Yang, Caixia; Wang, Yongheng; Lin, Gan; Yang, Yuhui; Wang, Xiaoyong; Zhu, Jun; Chen, Xiaoyuan; Lu, Xin; Liu, Gang; Xia, Haiping

    2016-01-01

    The coordinating atoms in polydentate chelates are primarily heteroatoms. We present the first examples of pentadentate chelates with all binding atoms of the chelating agent being carbon atoms, denoted as CCCCC chelates. Having up to five metal-carbon bonds in the equatorial plane has not been previously observed in transition metal chemistry. Density functional theory calculations showed that the planar metallacycle has extended Craig-Möbius aromaticity arising from 12-center–12-electron dπ-pπ π-conjugation. These planar chelates have broad absorption in the ultraviolet-visible–near-infrared region and, thus, notable photothermal performance upon irradiation by an 808-nm laser, indicating that these chelates have potential applications in photothermal therapy. The combination of facile synthesis, high stability, and broad absorption of these complexes could make the polydentate carbon chain a novel building block in coordination chemistry. PMID:27574707

  13. Zinc chelation reduces hippocampal neurogenesis after pilocarpine-induced seizure.

    Directory of Open Access Journals (Sweden)

    Jin Hee Kim

    Full Text Available Several studies have shown that epileptic seizures increase hippocampal neurogenesis in the adult. However, the mechanism underlying increased neurogenesis after seizures remains largely unknown. Neurogenesis occurs in the subgranular zone (SGZ of the hippocampus in the adult brain, although an understanding of why it actively occurs in this region has remained elusive. A high level of vesicular zinc is localized in the presynaptic terminals of the SGZ. Previously, we demonstrated that a possible correlation may exist between synaptic zinc localization and high rates of neurogenesis in this area after hypoglycemia. Using a lithium-pilocarpine model, we tested our hypothesis that zinc plays a key role in modulating hippocampal neurogenesis after seizure. Then, we injected the zinc chelator, clioquinol (CQ, 30 mg/kg, into the intraperitoneal space to reduce brain zinc availability. Neuronal death was detected with Fluoro Jade-B and NeuN staining to determine whether CQ has neuroprotective effects after seizure. The total number of degenerating and live neurons was similar in vehicle and in CQ treated rats at 1 week after seizure. Neurogenesis was evaluated using BrdU, Ki67 and doublecortin (DCX immunostaining 1 week after seizure. The number of BrdU, Ki67 and DCX positive cell was increased after seizure. However, the number of BrdU, Ki67 and DCX positive cells was significantly decreased by CQ treatment. Intracellular zinc chelator, N,N,N0,N-Tetrakis (2-pyridylmethyl ethylenediamine (TPEN, also reduced seizure-induced neurogenesis in the hippocampus. The present study shows that zinc chelation does not prevent neurodegeneration but does reduce seizure-induced progenitor cell proliferation and neurogenesis. Therefore, this study suggests that zinc has an essential role for modulating hippocampal neurogenesis after seizure.

  14. Combined Chelation Therapy with Deferasirox and Deferoxamine in Thalassemia

    OpenAIRE

    Lal, Ashutosh; Porter, John; Sweeters, Nancy; Ng, Vivian; Evans, Patricia; Neumayr, Lynne; Kurio, Gregory; Harmatz, Paul; Vichinsky, Elliott

    2012-01-01

    Iron overload is the primary cause of mortality and morbidity in thalassemia major despite advances in chelation therapy. We performed a pilot clinical trial to evaluate the safety and efficacy of combined therapy with deferasirox (DFX, 20-30 mg/kg daily) and deferoxamine (DFO, 35-50 mg/kg on 3-7 days/week) in 22 patients with persistent iron overload or organ damage. In the 18 subjects completing 12 months of therapy, median liver iron concentration decreased by 31% from 17.4 mg/g (range 3.9...

  15. Complexation and Antimicrobial Studies of Some Divalent Metal Chelates

    Directory of Open Access Journals (Sweden)

    Suparna Ghosh

    2010-01-01

    Full Text Available Metal chelates of Ni(II and Cu(II with the ligand 5-acetamido-1,3,4-thiadiazole-2-sulphonamide have been synthesized. The isolated compounds have been characterized by elemental analysis, molar conductivity, magnetic moment, electronic and IR spectral studies. The analytical data reflects the metal to ligand stoichiometry to be 1: 2. The conductivity data of the complexes also suggests their non-electrolytic nature. The stability constants and free energy change for the complexes have been calculated.. Ligand and their complexes have been screened for their biological activity and the data show good activity of these complexes and ligands.

  16. Synthesis and Adsorption Properties of Polystyrene-supported Chelating Resins Containing Heterocyclic Functional Groups

    Institute of Scientific and Technical Information of China (English)

    2005-01-01

    A series of new chelating resins with incorporating heterocyclic functional groups:pyridine, thiadizole, benzothizole into macroporous chloromethylated polystyrene were synthesized via hydrophilic spacer arm of polyethylene glycol co ntaining sulfur. These chelating resins were found to show high adsorption capacities for Ag+, Hg2+, Au3+ and Pd2+, and the presence of spacer arm can enhance adsorption ability due to increase the hydrophilicity of the chelating resins.

  17. Alkenes as Chelating Groups in Diastereoselective Additions of Organometallics to Ketones.

    Science.gov (United States)

    Raffier, Ludovic; Gutierrez, Osvaldo; Stanton, Gretchen R; Kozlowski, Marisa C; Walsh, Patrick J

    2014-10-13

    Alkenes have been discovered to be chelating groups to Zn(II), enforcing highly stereoselective additions of organozincs to β,γ-unsaturated ketones. (1)H NMR studies and DFT calculations provide support for this surprising chelation mode. The results expand the range of coordinating groups for chelation-controlled carbonyl additions from heteroatom Lewis bases to simple C-C double bonds, broadening the 60 year old paradigm.

  18. Performance of Nonmigratory Iron Chelating Active Packaging Materials in Viscous Model Food Systems.

    Science.gov (United States)

    Roman, Maxine J; Decker, Eric A; Goddard, Julie M

    2015-09-01

    Many packaged food products undergo quality deterioration due to iron promoted oxidative reactions. Recently, we have developed a nonmigratory iron chelating active packaging material that represents a novel approach to inhibit oxidation of foods while addressing consumer demands for "cleanˮ labels. A challenge to the field of nonmigratory active packaging is ensuring that surface-immobilized active agents retain activity in a true food system despite diffusional limitations. Yet, the relationship between food viscosity and nonmigratory active packaging activity retention has never been characterized. The objective of this study was to investigate the influence of food viscosity on iron chelation by a nonmigratory iron chelating active packaging material. Methyl cellulose was added to aqueous buffered iron solutions to yield model systems with viscosities ranging from ∼1 to ∼10(5)  mPa·s, representing viscosities ranging from beverage to mayonnaise. Iron chelation was quantified by material-bound iron content using colorimetry and inductively coupled plasma-optical emission spectrometry (ICP-OES).  Maximum iron chelation was reached in solutions up to viscosity ∼10(2)  mPa·s. In more viscous solutions (up to ∼10(4)  mPa·s), there was a significant decrease in iron chelating capacity (P influence of different food hydrocolloids on the performance of nonmigratory iron chelating active packaging was characterized. Methyl cellulose and carrageenan did not compete with the material for specific iron chelation (P > 0.05). Materials retained 32% to 45% chelating capacity when in contact with competitively chelating hydrocolloids guar gum, locust bean gum, and xanthan gum. This work demonstrates the potential application of nonmigratory iron chelating active packaging in liquid and semi-liquid foods to allow for the removal of synthetic chelators, while maintaining food quality.

  19. Uranyl(VI) nitrate salts: Modeling thermodynamic properties using the binding mean spherical approximation theory and determination of 'fictive' binary data

    Energy Technology Data Exchange (ETDEWEB)

    Ruas, Alexandre; Bernard, Olivier; Caniffi, Barbara; Simonin, Jean-Pierre; Turq, Pierre; Blum, Lesser; Moisy, Philippe [CEA-Valrho Marcoule, DEN/DRCP/SCPS/LCA, Bat 399, BP 17171, 30207 Bagnols-sur-Ceze Cedex (France); Laboratoire LI2C (UMR 7612), Universite P. M. Curie, Boite No. 51, 4 Place Jussieu, 75252 Paris Cedex 05 (France); Department of Physics, POB 23343, University of Puerto Rico, Rio Pedras, Puerto Rico 00931-3343 (United States)

    2006-07-01

    This work is aimed at a description of the thermodynamic properties of highly concentrated aqueous solutions of uranyl nitrate at 25 degrees C. A new resolution of the binding mean spherical approximation (BIMSA) theory, taking into account 1-1 and also 1-2 complex formation, is developed and used to reproduce, from a simple procedure, experimental uranyl nitrate osmotic coefficient variation with concentration. For better consistency of the theory, binary uranyl perchlorate and chloride osmotic coefficients are also calculated. Comparison of calculated and experimental values is made. The possibility of regarding the ternary system UO{sub 2}(NO{sub 3}){sub 2}/HNO{sub 3}/H{sub 2}O as a 'simple' solution (in the sense of Zdanovskii, Stokes, and Robinson) is examined from water activity and density measurements. Also, an analysis of existing uranyl nitrate binary data is proposed and compared with our obtained data. On the basis of the concept of 'simple' solution, values for density and water activity for the binary system UO{sub 2}(NO{sub 3}){sub 2}/H{sub 2}O are proposed in a concentration range on which uranyl nitrate precipitates from measurements on concentrated solutions of the ternary System UO{sub 2}(NO{sub 3}){sub 2}/HNO{sub 3}/H{sub 2}O. This new set of binary data is 'fictive' in the sense that the real binary system is not stable chemically. Finally, a new, interesting predictive capability of the BIMSA theory is shown. (authors)

  20. Effect of temperature on the mechanisms of interaction between uranyl ion and zirconium oxo-phosphate; Effet de la temperature sur les mechanismes d'interaction entre l'ion uranyle et l'oxophosphate de zirconium

    Energy Technology Data Exchange (ETDEWEB)

    Almazan Torres, Maria Guadalupe [Universite de Paris XI Orsay, Orsay (France)

    2007-07-01

    Uranium sorption onto Zr{sub 2}O(PO{sub 4}){sub 2} has been studied between 298 K and 363 K, in 0.1 M NaClO{sub 4} medium. Potentiometric titrations were realized to determine temperature dependency of the acid-base properties (pH{sub pcn}, acidity constants). Classical batch experiments were performed at different temperatures. The sorption experiments revealed that the uranium sorption onto Zr{sub 2}O(PO{sub 4}){sub 2} is favoured with the temperature. Structural characterization of the surface complexes was performed by both Time-Resolved Laser-Induced Fluorescence (TRLIF) and EXAFS spectroscopy. The TRLIF measurements vs. temperature revealed two uranyl surface complexes. No influence of the temperature onto the nature surface complex was observed. The EXAFS analysis showed a splitting of the equatorial oxygen atoms in two shells, corresponding to uranyl bidentate, inner-sphere complexes. The obtained structural uranyl surface complex information was used to simulate (using a constant capacitance model) the sorption edges. The proposed complexes equilibrium model consists of the following surface complexes: ({identical_to}ZrOH){sub 2}UO{sub 2}{sup 2+} and ({identical_to}PO){sub 2}UO{sub 2}. Besides the stability constants for the surface complexes, the thermodynamic parameters {delta}H{sup 0} and {delta}S{sup 0} were determined using the van't Hoff equation. The enthalpy values associated to the U(VI) retention onto Zr{sub 2}O(PO{sub 4}){sub 2}, determined by the temperature dependence of the stability constants, testify that the formation of the complex ({identical_to}PO){sub 2}UO{sub 2} (55 kJ/mol) is endothermic, while no influence of the temperature was observed for the formation of the complex ({identical_to}ZrOH){sub 2}UO{sub 2}{sup 2+}. The adsorption reaction of the last complex is then driven by entropy. In addition, calorimetric measurements of uranium sorption onto Zr{sub 2}O(PO{sub 4}){sub 2} were carried out to directly quantify the enthalpy

  1. Effect of metal chelators on the oxidative stability of model wine.

    Science.gov (United States)

    Kreitman, Gal Y; Cantu, Annegret; Waterhouse, Andrew L; Elias, Ryan J

    2013-10-02

    Oxidation is a major problem with respect to wine quality, and winemakers have few tools at their disposal to control it. In this study, the effect of exogenous Fe(II) (bipyridine; Ferrozine) and Fe(III) chelators (ethylenediaminetetraacetic acid, EDTA; phytic acid) on nonenzymatic wine oxidation was examined. The ability of these chelators to affect the formation of 1-hydroxyethyl radicals (1-HER) and acetaldehyde was measured using a spin trapping technique with electron paramagnetic resonance (EPR) and by HPLC-PDA, respectively. The chelators were then investigated for their ability to prevent the oxidative loss of an important aroma-active thiol, 3-mercaptohexan-1-ol (3MH). The Fe(II)-specific chelators were more effective than the Fe(III) chelators with respect to 1-HER inhibition during the early stages of oxidation and significantly reduced oxidation markers compared to a control during the study. However, although the addition of Fe(III) chelators was less effective or even showed an initial pro-oxidant activity, the Fe(III) chelators proved to be more effective antioxidants compared to Fe(II) chelators after 8 days of accelerated oxidation. In addition, it is shown for the first time that Fe(II) and Fe(III) chelators can significantly inhibit the oxidative loss of 3MH in model wine.

  2. Acetylcholine receptor antibody

    Science.gov (United States)

    ... page: //medlineplus.gov/ency/article/003576.htm Acetylcholine receptor antibody To use the sharing features on this page, please enable JavaScript. Acetylcholine receptor antibody is a protein found in the blood ...

  3. Antinuclear antibody panel

    Science.gov (United States)

    ... page: //medlineplus.gov/ency/article/003535.htm Antinuclear antibody panel To use the sharing features on this page, please enable JavaScript. The antinuclear antibody panel is a blood test that looks at ...

  4. Lyme disease antibody

    Science.gov (United States)

    ... JavaScript. The Lyme disease blood test looks for antibodies in the blood to the bacteria that causes ... needed. A laboratory specialist looks for Lyme disease antibodies in the blood sample using the ELISA test . ...

  5. The antibody mining toolbox

    OpenAIRE

    D'Angelo, Sara; Glanville, Jacob; Ferrara, Fortunato; Naranjo, Leslie; Gleasner, Cheryl D.; Shen, Xiaohong; Bradbury, Andrew RM; Kiss, Csaba

    2013-01-01

    In vitro selection has been an essential tool in the development of recombinant antibodies against various antigen targets. Deep sequencing has recently been gaining ground as an alternative and valuable method to analyze such antibody selections. The analysis provides a novel and extremely detailed view of selected antibody populations, and allows the identification of specific antibodies using only sequencing data, potentially eliminating the need for expensive and laborious low-throughput ...

  6. Multivalent chelators for spatially and temporally controlled protein functionalization.

    Science.gov (United States)

    You, Changjiang; Piehler, Jacob

    2014-05-01

    Site-specific protein modification-e.g. for immobilization or labelling-is a key prerequisite for numerous bioanalytical applications. Although modification by use of short peptide tags is particularly attractive, efficient and bio-orthogonal systems are still lacking. Here, we review the application of multivalent chelators (MCH) for high-affinity yet reversible recognition of oligohistidine (His)-tagged proteins. MCH are based on multiple nitrilotriacetic acid (NTA) moieties grafted on to molecular scaffolds suitable for conjugation to surfaces, probes or other biomolecules. Reversible interaction with the His-tag is mediated via transition metal ions chelated by the NTA moieties. The small size and biochemical compatibility of these recognition units and the possibility of rapid dissociation of the interaction with His-tagged proteins despite sub-nanomolar binding affinity, enable distinct and versatile handling and modification of recombinant proteins. In this review, we briefly introduce the key principles and features of MCH-His-tag interactions and recapitulate the broad spectrum of bioanalytical applications with a focus on quantitative protein interaction analysis on micro or nano-patterned solid surfaces and specific protein labelling in living cells.

  7. Selective separation of indium by iminodiacetic acid chelating resin

    Directory of Open Access Journals (Sweden)

    M. C. B. Fortes

    2007-06-01

    Full Text Available Indium can be recovered by treating residues, flue dusts, slags, and metallic intermediates in zinc smelting. This paper investigates the adsorption characteristics of indium and iron on an iminodiacetic acid chelating resin, Amberlite®IRC748 (Rohm and Haas Co.-USA. High concentrations of iron are always present in the aqueous feed solution of indium recovery. In addition, the chemical behaviour of iron in adsorptive systems is similar to that of indium. The metal concentrations in the aqueous solution were based on typical indium sulfate leach liquor obtained from zinc hydrometallurgical processing in a Brazilian plant. The ionic adsorption experiments were carried out by the continuous column method. Amberlite®IRC748 resin had a high affinity for indium under acidic conditions. Indium ions adsorbed onto the polymeric resin were eluted with a 0.5mol/dm³ sulphuric acid solution passed through the resin bed in the column. 99.5% pure indium sulfate aqueous solution was obtained using the iminodiacetic acid chelating resin Amberlite®IRC748.

  8. Deferasirox, an oral chelator in the treatment of iron overload

    Directory of Open Access Journals (Sweden)

    I. Portioli

    2013-05-01

    Full Text Available BACKGROUND Deferasirox is a once-daily oral iron chelator developed for treating iron overload complicating long-term transfusion therapy in patients with diseases such as beta-thalassemia and myelodysplastic syndromes. Iron overload can damage the liver, pancreas and the heart. Deferoxamine, the only other drug approved for iron chelation, can prevent these effects but requires parenteral administration. Deferasirox has been approved after a one-year, open-label trial in patients ≥ 2 years old with beta-thalassemia and transfusional emosiderosis randomized to once-daily oral 5, 10, 20, 30 mg/kg/day in comparison of subcutaneous deferoxamine 20-60 mg/mg/kg/day x 5/week. CONCLUSIONS Deferasirox 20-30 mg/kg/day produced reductions in liver iron concentration (LIC similar to those with deferoxamine. Adverse effect of deferasirox (increases of serum creatinine and aminotransferases, including the gastrointestinal ones, are similar but more frequent than those occurring with deferoxamine. Information is lacking on the effects of deferasirox on cardiac iron and cardiac dysfunction which is the most serious complication of transfusional iron overload.

  9. Magnetic memory effect in chelated zero valent iron nanoparticles

    Energy Technology Data Exchange (ETDEWEB)

    Ghosh, N., E-mail: nilotpal@vit.ac.in [School of Advanced Sciences, VIT University, Vellore 632014, Tamilnadu (India); Mandal, B.K.; Mohan Kumar, K. [School of Advanced Sciences, VIT University, Vellore 632014, Tamilnadu (India)

    2012-11-15

    We report the study of nonequilibrium magnetic behavior of air stable zero valent iron nanoparticles synthesized in presence of N-cetyl-N,N,N-trimethyl ammonium bromide chelating agent. X-ray photoelectron spectroscopy study has suggested the presence of iron oxides on nZVI surfaces. Zero-field-cooled and field-cooled magnetization measurements have been carried out at 20-300 K and 100 Oe. For field-cooled measurements with 1 h stops at 200, 100 and 50 K when compared with the warming cycle, we found the signature of magnetic memory effect. A study of magnetic relaxation at the same temperatures shows the existence of two relaxation times. - Highlights: Black-Right-Pointing-Pointer Zero valent iron nanoparticles are synthesized with CTAB chelating agent. Black-Right-Pointing-Pointer X-ray photoelectron spectroscopy study has shown the presence of iron oxide. Black-Right-Pointing-Pointer Magnetization measurement has displayed signature of magnetic memory. Black-Right-Pointing-Pointer Magnetization measurement with time suggested presence of 2 relaxation times.

  10. Chelating polymeric beads as potential therapeutics for Wilson's disease.

    Science.gov (United States)

    Mattová, Jana; Poučková, Pavla; Kučka, Jan; Skodová, Michaela; Vetrík, Miroslav; Stěpánek, Petr; Urbánek, Petr; Petřík, Miloš; Nový, Zbyněk; Hrubý, Martin

    2014-10-01

    Wilson's disease is a genetic disorder caused by a malfunction of ATPase 7B that leads to high accumulation of copper in the organism and consequent toxic effects. We propose a gentle therapy to eliminate the excessive copper content with oral administration of insoluble non-resorbable polymer sorbents containing selective chelating groups for copper(II). Polymeric beads with the chelating agents triethylenetetramine, N,N-di(2-pyridylmethyl)amine, and 8-hydroxyquinoline (8HQB) were investigated. In a preliminary copper uptake experiment, we found that 8HQB significantly reduced copper uptake (using copper-64 as a radiotracer) after oral administration in Wistar rats. Furthermore, we measured organ radioactivity in rats to demonstrate that 8HQB radiolabelled with iodine-125 is not absorbed from the gastrointestinal tract after oral administration. Non-resorbability and the blockade of copper uptake were also confirmed with small animal imaging (PET/CT) in mice. In a long-term experiment with Wistar rats fed a diet containing the polymers, we have found that there were no signs of polymer toxicity and the addition of polymers to the diet led to a significant reduction in the copper contents in the kidneys, brains, and livers of the rats. We have shown that polymers containing specific ligands could potentially be novel therapeutics for Wilson's disease.

  11. Functional characterization of the chloroplast ferric chelate oxidoreductase enzyme.

    Science.gov (United States)

    Solti, Adám; Müller, Brigitta; Czech, Viktória; Sárvári, Éva; Fodor, Ferenc

    2014-05-01

    Iron (Fe) has an essential role in the biosynthesis of chlorophylls and redox cofactors, and thus chloroplast iron uptake is a process of special importance. The chloroplast ferric chelate oxidoreductase (cFRO) has a crucial role in this process but it is poorly characterized. To study the localization and mechanism of action of cFRO, sugar beet (Beta vulgaris cv Orbis) chloroplast envelope fractions were isolated by gradient ultracentrifugation, and their purity was tested by western blotting against different marker proteins. The ferric chelate reductase (FCR) activity of envelope fractions was studied in the presence of NAD(P)H (reductants) and FAD coenzymes. Reduction of Fe(III)-ethylenediaminetetraacetic acid was monitored spectrophotometrically by the Fe(II)-bathophenanthroline disulfonate complex formation. FCR activity, that is production of free Fe(II) for Fe uptake, showed biphasic saturation kinetics, and was clearly associated only to chloroplast inner envelope (cIE) vesicles. The reaction rate was > 2.5 times higher with NADPH than with NADH, which indicates the natural coenzyme preference of cFRO activity and its dependence on photosynthesis. FCR activity of cIE vesicles isolated from Fe-deficient plants also showed clear biphasic kinetics, where the KM of the low affinity component was elevated, and thus this component was down-regulated.

  12. Selective separation of indium by iminodiacetic acid chelating resin

    Energy Technology Data Exchange (ETDEWEB)

    Fortes, M.C.B.; Benedetto, J.S. [Centro de Desenvolvimento da Tecnologia Nuclear (CDTN/CNEN-MG), Belo Horizonte, MG (Brazil); Martins, A.H. [Universidade Federal de Minas Gerais (UFMG), Belo Horizonte, MG (Brazil). Dept. de Engenharia Metalurgica e de Materiais]. E-mail: ahmartin@demet.ufmg.br

    2007-04-15

    - Indium can be recovered by treating residues, flue dusts, slags, and metallic intermediates in zinc smelting. This paper investigates the adsorption characteristics of indium and iron on an iminodiacetic acid chelating resin, Amberlite{sup R} IRC748 (Rohm and Haas Co.-USA). High concentrations of iron are always present in the aqueous feed solution of indium recovery. In addition, the chemical behaviour of iron in adsorptive systems is similar to that of indium. The metal concentrations in the aqueous solution were based on typical indium sulfate leach liquor obtained from zinc hydrometallurgical processing in a Brazilian plant. The ionic adsorption experiments were carried out by the continuous column method. Amberlite{sup R} IRC748 resin had a high affinity for indium under acidic conditions. Indium ions adsorbed onto the polymeric resin were eluted with a 0.5 mol/dm{sup 3} sulphuric acid solution passed through the resin bed in the column. 99.5% pure indium sulfate aqueous solution was obtained using the iminodiacetic acid chelating resin Amberlite{sup R} IRC748. (author)

  13. Using iron chelating agents to enhance dermatological PDT

    Science.gov (United States)

    Curnow, Alison; Dogra, Yuktee; Winyard, Paul; Campbell, Sandra

    2009-06-01

    Topical protoporphyrin IX (PPIX) induced photodynamic therapy (PDT) of basal cell carcinoma (BCC) produces good clinical outcomes with excellent cosmesis as long as the disease remains superficial. Efficacy for nodular BCC however appears inferior to standard treatment unless repeat treatments are performed. Enhancement is therefore required and is possible by employing iron chelating agents to temporarily increase PPIX accumulation above the levels normally obtained using aminolevulinic acid (ALA) or the methyl ester of ALA (MAL) alone. In vitro studies investigated the effect of the novel iron chelator, CP94 on necrotic or apoptotic cell death in cultured human skin fibroblasts and epidermal carcinoma cells incubated with MAL. Furthermore, following a dose escalating safety study conducted with ALA in patients, an additional twelve nodular BCCs were recruited for topical treatment with standard MAL-PDT +/- increasing doses of CP94. Six weeks later following clinical assessment, the whole treatment site was excised for histological analysis. CP94 produced greater cell death in vitro when administered in conjunction with MAL than this porphyrin precursor could produce when administered alone. Clinically, PDT treatment using Metvix + CP94 was a simple and safe modification associated with a trend of reduced tumor thickness with increasing CP94 dose.

  14. Time-Resolved Infrared Reflectance Studies of the Dehydration-Induced Transformation of Uranyl Nitrate Hexahydrate to the Trihydrate Form

    Energy Technology Data Exchange (ETDEWEB)

    Johnson, Timothy J.; Sweet, Lucas E.; Meier, David E.; Mausolf, Edward J.; Kim, Eunja; Weck, Philippe F.; Buck, Edgar C.; McNamara, Bruce K.

    2015-10-01

    Uranyl nitrate is a key species in the nuclear fuel cycle. However, this species is known to exist in different states of hydration, including the hexahydrate ([UO2(NO3)2(H2O)6] often called UNH), the trihydrate [UO2(NO3)2(H2O)3 or UNT], and in very dry environments the dihydrate form [UO2(NO3)2(H2O)2]. Their relative stabilities depend on both water vapor pressure and temperature. In the 1950s and 1960s the different phases were studied by infrared transmission spectroscopy, but were limited both by instrumental resolution and by the ability to prepare the samples for transmission. We have revisited this problem using time-resolved reflectance spectroscopy, which requires no sample preparation and allows dynamic analysis while the sample is exposed to a flow of N2 gas. Samples of known hydration state were prepared and confirmed via X-ray diffraction patterns of known species. In reflectance mode the hexahydrate UO2(NO3)2(H2O)6 has a distinct uranyl asymmetric stretch band at 949.0 cm-1 that shifts to shorter wavelengths and broadens as the sample desiccates and recrystallizes to the trihydrate, first as a shoulder growing in on the blue edge but ultimately results in a doublet band with reflectance peaks at 966 and 957 cm-1. The data are consistent with transformation from UNH to UNT as UNT has two inequivalent UO22+ sites. The dehydration of UO2(NO3)2(H2O)6 to UO2(NO3)2(H2O)3 is both a structural and morphological change that has the lustrous lime green UO2(NO3)2(H2O)6 crystals changing to the matte greenish yellow of the trihydrate solid. The phase transformation and crystal structures were confirmed by density functional theory calculations and optical microscopy methods, both of which showed a transformation with two distinct sites for the uranyl cation in the trihydrate, with but one in the hexahydrate.

  15. Gold nanoparticles functionalised with fast water exchanging Gd3+ chelates: linker effects on the relaxivity.

    Science.gov (United States)

    Ferreira, Miguel F; Gonçalves, Janaina; Mousavi, Bibimaryam; Prata, Maria I M; Rodrigues, Sérgio P J; Calle, Daniel; López-Larrubia, Pilar; Cerdan, Sebastian; Rodrigues, Tiago B; Ferreira, Paula M; Helm, Lothar; Martins, José A; Geraldes, Carlos F G C

    2015-03-07

    The relaxivity displayed by Gd(3+) chelates immobilized onto gold nanoparticles is the result of the complex interplay between the nanoparticle size, the water exchange rate and the chelate structure. In this work we study the effect of the length of ω-thioalkyl linkers, anchoring fast water exchanging Gd(3+) chelates onto gold nanoparticles, on the relaxivity of the immobilized chelates. Gold nanoparticles functionalized with Gd(3+) chelates of mercaptoundecanoyl and lipoyl amide conjugates of the DO3A-N-(α-amino)propionate chelator were prepared and studied as potential CA for MRI. High relaxivities per chelate, of the order of magnitude 28-38 mM(-1) s(-1) (30 MHz, 25 °C), were attained thanks to simultaneous optimization of the rotational correlation time and of the water exchange rate. Fast local rotational motions of the immobilized chelates around connecting linkers (internal flexibility) still limit the attainable relaxivity. The degree of internal flexibility of the immobilized chelates seems not to be correlated with the length of the connecting linkers. Biodistribution and MRI studies in mice suggest that the in vivo behavior of the gold nanoparticles was determined mainly by size. Small nanoparticles (HD = 3.9 nm) undergo fast renal clearance and avoidance of the RES organs while larger nanoparticles (HD = 4.8 nm) undergo predominantly hepatobiliary excretion. High relaxivities, allied to chelate and nanoparticle stability and fast renal clearance in vivo suggest that functionalized gold nanoparticles hold great potential for further investigation as MRI contrast agents. This study contributes to a better understanding of the effect of linker length on the relaxivity of gold nanoparticles functionalized with Gd(3+) complexes. It is a relevant contribution towards "design rules" for nanostructures functionalized with Gd(3+) chelates as Contrast Agents for MRI and multimodal imaging.

  16. An ultra-facile and label-free immunoassay strategy for detection of copper (II) utilizing chemiluminescence self-enhancement of Cu (II)-ethylenediaminetetraacetate chelate.

    Science.gov (United States)

    Ouyang, Hui; Shu, Qi; Wang, Wenwen; Wang, Zhenxing; Yang, Shijia; Wang, Lin; Fu, Zhifeng

    2016-11-15

    The establishment of facile, rapid, sensitive and cost-effective protocols for the detection of heavy metals is of great significance for human health and environmental monitoring. Hereby, an ultra-facile and label-free immunoassay strategy was designed for detecting heavy metal ion by using Cu (II) as the model analyte. Cu (II) reacted previously with ethylenediaminetetraacetate (EDTA) was captured by immobilized monoclonal antibody for Cu (II)-EDTA chelate. Then Cu (II) was detected based on the self-enhancing effect of Cu (II)-EDTA chelate to luminol-H2O2 chemiluminescence reaction. The CL intensity is linear relative with Cu (II) concentration in a very wide range of 1.0-1000ng/mL, with a detection limit of 0.33ng/mL (S/N=3). Since the specificity of this proposed strategy relied on both the specificity of monoclonal antibody and the specificity of luminol-H2O2 system, it could avoid interference from most common ions. The proposed method was used successfully to detect Cu (II) in traditional Chinese medicine and environmental water samples with acceptable recovery values of 82-113%. This proof-of-principle work demonstrated the feasibility of the label-free immunoassay for heavy metal ions, and opened a new avenue for rapid screening and field assay for drug safety, environmental monitoring and clinical diagnosis.

  17. Ethane 1-hydroxy-1, 1-diphosphonate (EHDP) counteracts the inhibitory effect of uranyl nitrate on bone formation

    Energy Technology Data Exchange (ETDEWEB)

    Ubios, A.M.; Guglielmotti, M.B. (Univ. of Buenos Aires (Argentina)); Cabrini, R.L. (Univ. of Buenos Aires (Argentina) National Atomic Energy Commission, Buenos Aires (Argentina))

    The beneficial effect of ethane 1-hydroxy-1, 1-diphosphonate (EHDP) in restoring the inhibition of bone formation in cases of acute uranium intoxication is presented. Bone formation was studied histomorphometrically in a model of alveolar bone healing. After tooth extraction, 40 rats were divided into 4 groups that received (1) no further treatment, (2) 10 daily intraperitoneal injections of 7.5 mg/kg of body weight of EHDP, (3) an intraperitoneal injection of 2.0 mg/kg of body weight of uranyl nitrate, and (4) the same treatment as was provided rats in groups 2 and 3. The results showed that the healing of bone did not occur in exposed animals, whereas healing in EHDP-treated exposed animals did not differ from that of nonexposed controls. This effect might result from a blocking and/or competitive action of EHDP and/or the stimulation that EHDP elicits at the doses and in the administration period studied.

  18. Solid state interaction studies on binary nitrate mixtures of uranyl nitrate hexahydrate and lanthanum nitrate hexahydrate at elevated temperatures

    Science.gov (United States)

    Kalekar, Bhupesh; Raje, Naina; Reddy, A. V. R.

    2017-02-01

    Interaction behavior of uranyl nitrate hexahydrate (UNH) and lanthanum nitrate hexahydrate (LaNH) have been investigated on the mixtures in different molar ratios of the two precursors and monitoring the reactions at elevated temperatures with thermoanalytical and X-ray diffraction measurement techniques. During the decomposition of equimolar mixture of LaNH and UNH, formation of lanthanum uranate (U0.5La0.5)O2, was seen by the temperature of 500 °C along with lanthanum oxide (La2O3) and uranium trioxide (UO3). By the temperature of 700 °C, the formation of uranium sesquioxide (U3O8) was observed along with (U0.5La0.5)O2 as end products in uranium rich mixtures. Lanthanum rich compositions decomposed by the temperature of 700 °C to give (U0.5La0.5)O2 and La2O3 as end products.

  19. Radiation chemistry of cis-syn-cis dicyclohexano-18-crown-6 (DCH18C6): Acidity and uranyl nitrate dependence

    Energy Technology Data Exchange (ETDEWEB)

    Draye, Micheline [Laboratoire de Chimie Moleculaire et Environnement (EA1651), Universite de Savoie-Polytech' Savoie, Campus Scientifique, 73376 Le Bourget du Lac Cedex (France)], E-mail: micheline.draye@univ-savoie.fr; Favre-Reguillon, Alain [Laboratoire de Chimie Organique (UMR7084), Conservatoire National des Arts et Metiers, 2 rue conte, 75003 Paris (France); Faure, Rene [Laboratoire des sciences analytiques, UMR CNRS 5180, Universite Claude Bernard, Lyon 1, 43 boulevard du 11 Novembre 1918, 69622 Villeurbanne Cedex (France); Lemaire, Marc [Laboratoire de Catalyse et Synthese Organique, UMR CNRS 5246, Institut de Chimie et Biochimie Moleculaires et Supramoleculaires, Universite Lyon 1 CPE, 43 boulevard du 11 novembre 1918, Villeurbanne 69622 (France)

    2008-05-15

    The cis-syn-cis isomer of dicyclohexano-18-crown-6 (DCH18C6) has been shown to be an efficient extractant able to perform the separation of Pu(IV) and U(VI) from fission products and then the separation of Pu(IV) from U(VI) without valence exchange as required in the PUREX process. This macrocycle was irradiated in nitric acid with a {sup 137}Cs {gamma} source to study its radiation chemical stability. Radiation chemical yields (G) were determined by gas chromatography. The results show that the presence of uranyl nitrate has a strong influence on DCH18C6 radiation chemical stability. Indeed, the presence of this template ion increases the macrocycle stability by promoting fragments recombination.

  20. Standard test methods for chemical, mass spectrometric, spectrochemical, nuclear, and radiochemical analysis of nuclear-grade uranyl nitrate solutions

    CERN Document Server

    American Society for Testing and Materials. Philadelphia

    1999-01-01

    1.1 These test methods cover procedures for the chemical, mass spectrometric, spectrochemical, nuclear, and radiochemical analysis of nuclear-grade uranyl nitrate solution to determine compliance with specifications. 1.2 The analytical procedures appear in the following order: Sections Determination of Uranium 7 Specific Gravity by Pycnometry 15-20 Free Acid by Oxalate Complexation 21-27 Determination of Thorium 28 Determination of Chromium 29 Determination of Molybdenum 30 Halogens Separation by Steam Distillation 31-35 Fluoride by Specific Ion Electrode 36-42 Halogen Distillate Analysis: Chloride, Bromide, and Iodide by Amperometric Microtitrimetry 43 Determination of Chloride and Bromide 44 Determination of Sulfur by X-Ray Fluorescence 45 Sulfate Sulfur by (Photometric) Turbidimetry 46 Phosphorus by the Molybdenum Blue (Photometric) Method 54-61 Silicon by the Molybdenum Blue (Photometric) Method 62-69 Carbon by Persulfate Oxidation-Acid Titrimetry 70 Conversion to U3O8 71-74 Boron by ...

  1. [VGKC-complex antibodies].

    Science.gov (United States)

    Watanabe, Osamu

    2013-04-01

    Various antibodies are associated with voltage-gated potassium channels (VGKCs). Representative antibodies to VGKCs were first identified by radioimmunoassays using radioisotope-labeled alpha-dendrotoxin-VGKCs solubilized from rabbit brain. These antibodies were detected only in a proportion of patients with acquired neuromyotonia (Isaacs' syndrome). VGKC antibodies were also detected in patients with Morvan's syndrome and in those with a form of autoimmune limbic encephalitis. Recent studies indicated that the "VGKC" antibodies are mainly directed toward associated proteins (for example LGI-1 and CASPR-2) that complex with the VGKCs themselves. The "VGKC" antibodies are now commonly known as VGKC-complex antibodies. In general, LGI-1 antibodies are most commonly detected in patients with limbic encephalitis with syndrome of inappropriate secretion of antidiuretic hormone. CASPR-2 antibodies are present in the majority of patients with Morvan's syndrome. These patients develop combinations of CNS symptoms, autonomic dysfunction, and peripheral nerve hyperexcitability. Furthermore, VGKC-complex antibodies are tightly associated with chronic idiopathic pain. Hyperexcitability of nociceptive pathways has also been implicated. These antibodies may be detected in sera of some patients with neurodegenerative diseases (for example, amyotrophic lateral sclerosis and Creutzfeldt-Jakob disease).

  2. An experimental and ab initio study on the abiotic reduction of uranyl by ferrous iron

    Science.gov (United States)

    Taylor, S. D.; Marcano, M. C.; Rosso, K. M.; Becker, U.

    2015-05-01

    It is important to understand the mechanisms controlling the removal of uranyl from solution from an environmental standpoint, particularly whether soluble Fe(II) is capable of reducing soluble U(VI) to insoluble U(IV). Experiments were performed to shed light into discrepancies of recent studies about precipitation of U-containing solids without changing oxidation states versus precipitation/reduction reactions, especially with respect to the kinetics of these reactions. To understand the atomistic mechanisms, thermodynamics, and kinetics of these redox processes, ab initio electron transfer (ET) calculations, using Marcus theory, were applied to study the reduction of U(VI)aq to U(V)aq by Fe(II)aq (the first rate-limiting ET-step). Outer-sphere (OS) and inner-sphere (IS) Fe-U complexes were modeled to represent simple species within a homogeneous environment through which ET could occur. Experiments on the chemical reduction were performed by reacting 1 mM Fe(II)aq at pH 7.2 with high (i.e., 0.16 mM) and lower (i.e., 0.02 mM) concentrations of U(VI)aq. At higher U concentration, a rapid decrease in U(VI)aq was observed within the first hour of reaction. XRD and XPS analyses of the precipitates confirmed the presence of (meta)schoepite phases, where up to ∼25% of the original U was reduced to U4+ and/or U5+-containing phases. In contrast, at 0.02 mM U, the U(VI)aq concentration remained fairly constant for the first 3 h of reaction and only then began to decrease due to slower precipitation kinetics. XPS spectra confirm the partial chemical reduction U associated with the precipitate (up to ∼30%). Thermodynamic calculations support that the reduction of U(VI)aq to U(IV)aq by Fe(II)aq is energetically unfavorable. The batch experiments in this study show U(VI) is removed from solution by precipitation and that transitioning to a heterogeneous system in turn enables the solid U phase to be partially reduced. Ab initio ET calculations revealed that OS ET is

  3. Design and Construction of Experiment for Direct Electron Irradiation of Uranyl Sulfate Solution: Bubble Formation and Thermal Hydraulics Studies

    Energy Technology Data Exchange (ETDEWEB)

    Chemerisov, Sergey [Argonne National Lab. (ANL), Argonne, IL (United States); Gromov, Roman [Argonne National Lab. (ANL), Argonne, IL (United States); Makarashvili, Vakho [Argonne National Lab. (ANL), Argonne, IL (United States); Heltemes, Thad [Argonne National Lab. (ANL), Argonne, IL (United States); Sun, Zaijing [Argonne National Lab. (ANL), Argonne, IL (United States); Wardle, Kent E. [Argonne National Lab. (ANL), Argonne, IL (United States); Bailey, James [Argonne National Lab. (ANL), Argonne, IL (United States); Quigley, Kevin [Argonne National Lab. (ANL), Argonne, IL (United States); Stepinski, Dominique [Argonne National Lab. (ANL), Argonne, IL (United States); Vandegrift, George [Argonne National Lab. (ANL), Argonne, IL (United States)

    2014-10-01

    Argonne is assisting SHINE Medical Technologies in developing SHINE, a system for producing fission-product 99Mo using a D/T-accelerator to produce fission in a non-critical target solution of aqueous uranyl sulfate. We have developed an experimental setup for studying thermal-hydraulics and bubble formation in the uranyl sulfate solution to simulate conditions expected in the SHINE target solution during irradiation. A direct electron beam from the linac accelerator will be used to irradiate a 20 L solution (sector of the solution vessel). Because the solution will undergo radiolytic decomposition, we will be able to study bubble formation and dynamics and effects of convection and temperature on bubble behavior. These experiments will serve as a verification/ validation tool for the thermal-hydraulic model. Utilization of the direct electron beam for irradiation allows homogeneous heating of a large solution volume and simplifies observation of the bubble dynamics simultaneously with thermal-hydraulic data collection, which will complement data collected during operation of the miniSHINE experiment. Irradiation will be conducted using a 30-40 MeV electron beam from the high-power linac accelerator. The total electron-beam power will be 20 kW, which will yield a power density on the order of 1 kW/L. The solution volume will be cooled on the front and back surfaces and central tube to mimic the geometry of the proposed SHINE solution vessel. Also, multiple thermocouples will be inserted into the solution vessel to map thermal profiles. The experimental design is now complete, and installation and testing are in progress.

  4. Determination of the stability of the uranyl ion sipped in {tau}-hydrogen phosphate of zirconium in sodic form; Determinacion de la estabilidad del ion uranilo sorbido en {tau}-hidrogenofosfato de zirconio en forma sodica

    Energy Technology Data Exchange (ETDEWEB)

    Ordonez R, E.; Fernandez V, S.M. [ININ, 52045 Ocoyoacac, Estado de Mexico (Mexico); Drot, R.; Simoni, E. [Universite de Paris-Sud-XI, Institut de Physique Nucleaire d' Orsay, Groupe de radiochimie, Bat. 100, 91406 Orsay (France)]. e-mail: edo@nuclear.inin.mx

    2005-07-01

    The stability of the uranyl sipped in the zirconium {tau}-hydrogen phosphate in sodic form ({tau}-NaZrP), was carried out characterizing the complexes formed by Laser spectroscopy in the visible region and by X-ray photoelectron spectroscopy. The material was prepared by a new synthesis technique working in nitrogen atmosphere and to low temperatures. The sorption of the uranyl ion was made in acid media with concentrations of 10{sup -4} and 10{sup -5} of uranyl nitrate and with ion forces of 0.1 and 0.5 M of NaClO{sub 4}. The spectra of induced fluorescence with laser (TRLFS) show that the uranyl is fixed in very acid media in three well differentiated species, to pH less acid, the specie of long half life disappears and are only those of short half life. The results of the binding energy obtained by XPS indicate that the binding energy of the uranyl confer it a stable character to the complex formed in the {tau}-NaZP, that makes to this material appropriate to retain to the uranyl in solution to high ion forces and in acid media. (Author)

  5. THE SYNTHESIS OF URUSHIOL TITANIUM CHELATE POLYMERS AND THEIR STRUCTURAL CHARACTERISTICS

    Institute of Scientific and Technical Information of China (English)

    HU Binghuan; CHEN Wending; LIN Jinhuo

    1993-01-01

    The synthetic method and structural characteristics of urushiol-titanium chelates (UT) and urushiol-titanium chelate polymer for anticorrosive coatings have been studied.Two kinds of coating films made from UT polymer show excellent physico-mechanical properties and possess good chemical resistance to strong acids and alkalis, many kinds of salt solutions and organic solvents,stable at high temperature.

  6. A NOVEL METAL CHELATE AFFINITY ADSORBENT FOR PROTEIN UPTAKE

    Institute of Scientific and Technical Information of China (English)

    WANGYongjian; BAIShu; 等

    2001-01-01

    In this article,a spherical chitosan gel crosslinked by epichlorohydrin was prepared.It was then loaded with copper ions to produce a metal chelate affinity adsorbent for protein.The uptake of bovine serum albumin(BSA)by the affinity adsorbent was investigated.and the adsorption capacity for BSA as high as 40mg/g-wet beads was observed.The adsorption equilibrium data was well correlated by the Langmuir equation.The adsorption was considerably affected by pH.In additio.The amount of BSA adsorbed onto the beads decreased with the increasing of aqueous phase ionic strength,so adsorbed BAS can be desorbed by adjusting pH orionic strength of the solution.

  7. Synthesis and characterization of dihexyldithiocarbamate as a chelating agent in extraction of gold(III)

    Science.gov (United States)

    Fatimah, Soja Siti; Bahti, Husein H.; Hastiawan, Iwan; Permanasari, Anna

    2016-02-01

    The use of dialkyldithiocarbamates as chelating agents of transition metals have been developing for decades. Many chelating agents have been synthesized and used in the extraction of the metals. Studies on particular aspects of extraction of the metals, such as the effect of increasing hydrophobicity of chelating agents on the effectiveness of the extraction, have been done. However, despite the many studies on the synthesis and applications of this type of chelating agents, interests in the aspect of molecular structure of the synthesized ligands and of their complexes, have been limited. This study aimed at synthesizing and characterizing dihexylthiocarbamate, and using the ligand for the extraction of gold III). Characterization of the ligand and of its metal complex were done by using elemental analysis, DTG, and spectroscopic methods to include NMR, (1H, and 13C), FTIR, and MS-ESI. Data on the synthesis, characterization, and the application of the ligand as a chelating agent are presented.

  8. Synthesis and characterization of dihexyldithiocarbamate as a chelating agent in extraction of gold(III)

    Energy Technology Data Exchange (ETDEWEB)

    Fatimah, Soja Siti, E-mail: soja-sf@upi.edu [Departemen Pendidikan Kimia, Universitas Pendidikan Indonesia, Jl. Dr. Setiabudhi No. 229, Bandung 40154 (Indonesia); Department of Chemistry, Faculty of Mathematics and Natural Sciences, Padjadjaran University, Jl. Raya Bandung-Sumedang, Km. 21, Jatinangor (Indonesia); Bahti, Husein H.; Hastiawan, Iwan [Department of Chemistry, Faculty of Mathematics and Natural Sciences, Padjadjaran University, Jl. Raya Bandung-Sumedang, Km. 21, Jatinangor (Indonesia); Permanasari, Anna [Departemen Pendidikan Kimia, Universitas Pendidikan Indonesia, Jl. Dr. Setiabudhi No. 229, Bandung 40154 (Indonesia)

    2016-02-08

    The use of dialkyldithiocarbamates as chelating agents of transition metals have been developing for decades. Many chelating agents have been synthesized and used in the extraction of the metals. Studies on particular aspects of extraction of the metals, such as the effect of increasing hydrophobicity of chelating agents on the effectiveness of the extraction, have been done. However, despite the many studies on the synthesis and applications of this type of chelating agents, interests in the aspect of molecular structure of the synthesized ligands and of their complexes, have been limited. This study aimed at synthesizing and characterizing dihexylthiocarbamate, and using the ligand for the extraction of gold III). Characterization of the ligand and of its metal complex were done by using elemental analysis, DTG, and spectroscopic methods to include NMR, ({sup 1}H, and {sup 13}C), FTIR, and MS-ESI. Data on the synthesis, characterization, and the application of the ligand as a chelating agent are presented.

  9. Design and synthesis of zinc-selective chelators for extracellular applications.

    Science.gov (United States)

    Kawabata, Eri; Kikuchi, Kazuya; Urano, Yasuteru; Kojima, Hirotatsu; Odani, Akira; Nagano, Tetsuo

    2005-01-26

    Zinc (Zn2+) is found in every cell in human bodies. A few millimolar of free Zn2+ exists in the vesicles of presynaptic neurons in the mammalian brain and is released by synaptic activity or depolarization, modulating the function of certain ion channels and receptors. Although various chemical tools for measuring Zn2+ in biological samples, such as fluorescent probes for Zn2+, have been developed, Zn2+-selective chelators have room to be improved. Research on Zn2+ signals in the brain has traditionally employed several chelators, which have several shortcomings for biological applications. Here we report the design, synthesis, and properties of new membrane-impermeable chelators selective for Zn2+ and describe biological applications in hippocampal slices. As a result, our newly designed chelator revealed the first biological implication that presynaptic Zn2+ can be released in the CA1 region. This confirms the utility of these new chelatotrs as extracellular Zn2+ chelators for biological applications.

  10. Red Blood Cell Transfusion Independence Following the Initiation of Iron Chelation Therapy in Myelodysplastic Syndrome

    Directory of Open Access Journals (Sweden)

    Maha A. Badawi

    2010-01-01

    Full Text Available Iron chelation therapy is often used to treat iron overload in patients requiring transfusion of red blood cells (RBC. A 76-year-old man with MDS type refractory cytopenia with multilineage dysplasia, intermediate-1 IPSS risk, was referred when he became transfusion dependent. He declined infusional chelation but subsequently accepted oral therapy. Following the initiation of chelation, RBC transfusion requirement ceased and he remained transfusion independent over 40 months later. Over the same time course, ferritin levels decreased but did not normalize. There have been eighteen other MDS patients reported showing improvement in hemoglobin level with iron chelation; nine became transfusion independent, nine had decreased transfusion requirements, and some showed improved trilineage myelopoiesis. The clinical features of these patients are summarized and possible mechanisms for such an effect of iron chelation on cytopenias are discussed.

  11. Brazilian Thalassemia Association protocol for iron chelation therapy in patients under regular transfusion

    Directory of Open Access Journals (Sweden)

    Monica Pinheiro de Almeida Verissimo

    2013-01-01

    Full Text Available In the absence of an iron chelating agent, patients with beta-thalassemia on regular transfusions present complications of transfusion-related iron overload. Without iron chelation therapy, heart disease is the major cause of death; however, hepatic and endocrine complications also occur. Currently there are three iron chelating agents available for continuous use in patients with thalassemia on regular transfusions (desferrioxamine, deferiprone, and deferasirox providing good results in reducing cardiac, hepatic and endocrine toxicity. These practice guidelines, prepared by the Scientific Committee of Associação Brasileira de Thalassemia (ABRASTA, presents a review of the literature regarding iron overload assessment (by imaging and laboratory exams and the role of T2* magnetic resonance imaging (MRI to control iron overload and iron chelation therapy, with evidence-based recommendations for each clinical situation. Based on this review, the authors propose an iron chelation protocol for patients with thalassemia under regular transfusions.

  12. Effects of Zinc Chelators on Aflatoxin Production in Aspergillus parasiticus

    Science.gov (United States)

    Wee, Josephine; Day, Devin M.; Linz, John E.

    2016-01-01

    Zinc concentrations strongly influence aflatoxin accumulation in laboratory media and in food and feed crops. The presence of zinc stimulates aflatoxin production, and the absence of zinc impedes toxin production. Initial studies that suggested a link between zinc and aflatoxin biosynthesis were presented in the 1970s. In the present study, we utilized two zinc chelators, N,N,N′,N′-tetrakis (2-pyridylmethyl) ethane-1,2-diamine (TPEN) and 2,3-dimercapto-1-propanesulfonic acid (DMPS) to explore the effect of zinc limitation on aflatoxin synthesis in Aspergillus parasiticus. TPEN but not DMPS decreased aflatoxin biosynthesis up to six-fold depending on whether A. parasiticus was grown on rich or minimal medium. Although we observed significant inhibition of aflatoxin production by TPEN, no detectable changes were observed in expression levels of the aflatoxin pathway gene ver-1 and the zinc binuclear cluster transcription factor, AflR. Treatment of growing A. parasiticus solid culture with a fluorescent zinc probe demonstrated an increase in intracellular zinc levels assessed by increases in fluorescent intensity of cultures treated with TPEN compared to controls. These data suggest that TPEN binds to cytoplasmic zinc therefore limiting fungal access to zinc. To investigate the efficacy of TPEN on food and feed crops, we found that TPEN effectively decreases aflatoxin accumulation on peanut medium but not in a sunflower seeds-derived medium. From an application perspective, these data provide the basis for biological differences that exist in the efficacy of different zinc chelators in various food and feed crops frequently contaminated by aflatoxin. PMID:27271668

  13. Beryllium Chelation by Dicarboxylic Acids in Aqueous Solution.

    Science.gov (United States)

    Schmidt, Michael; Bauer, Andreas; Schmidbaur, Hubert

    1997-05-07

    Maleic and phthalic acids are found to react with Be(OH)(2), generated in situ from BeSO(4)(aq) and Ba(OH)(2)(aq), in aqueous solution at pH 3.0 or 4.4, respectively (25 degrees C), to give solutions containing the complexes (H(2)O)(2)Be[(OOCCH)(2)] (1) and (H(2)O)(2)Be[(OOC)(2)C(6)H(4)] (3). The products can be isolated in high yield and identified by microanalytical data. With 2 equiv of the dicarboxylic acids and the pH adjusted to 5.5 and 5.9, respectively, by addition of ammonia, the bis-chelate complexes [(NH(4))(+)](2){[Be[(OOCCH)(2)](2)}(2)(-) (2) and [(NH(4))(+)](2){Be[(OOC)(2)C(6)H(4)](2)}(2)(-) (4) are obtained, which can also be isolated. The compounds show distinct (9)Be, (1)H, and (13)C resonances in their NMR spectra in aqueous solutions. Layering of an aqueous solution of compound 4 with acetone at ambient temperature leads to the precipitation of single crystals suitable for an X-ray structure determination. This salt (5) was found to contain the bis-chelated dianion {Be[(OOC)(2)C(6)H(4)](2)}(2)(-) with the beryllium atom in the spiro center of two seven-membered rings and an overall geometry approaching closely C(2) symmetry. These anions are associated with two crystallographically independent but structurally similar counterions [MeC(O)CH(2)CMe(2)NH(3)](+), which are the product of a condensation reaction of the ammonium cation with the acetone solvent. In the crystal the ammonium hydrogen atoms of the cations form N-H.O hydrogen bonds with the oxo functions of the dianion.

  14. Mechanistic basis for overcoming platinum resistance using copper chelating agents.

    Science.gov (United States)

    Liang, Zheng D; Long, Yan; Tsai, Wen-Bin; Fu, Siqing; Kurzrock, Razelle; Gagea-Iurascu, Mihai; Zhang, Fan; Chen, Helen H W; Hennessy, Bryan T; Mills, Gordon B; Savaraj, Niramol; Kuo, Macus Tien

    2012-11-01

    Platinum-based antitumor agents are widely used in cancer chemotherapy. Drug resistance is a major obstacle to the successful use of these agents because once drug resistance develops, other effective treatment options are limited. Recently, we conducted a clinical trial using a copper-lowering agent to overcome platinum drug resistance in ovarian cancer patients and the preliminary results are encouraging. In supporting this clinical study, using three pairs of cisplatin (cDDP)-resistant cell lines and two ovarian cancer cell lines derived from patients who had failed in platinum-based chemotherapy, we showed that cDDP resistance associated with reduced expression of the high-affinity copper transporter (hCtr1), which is also a cDDP transporter, can be preferentially resensitized by copper-lowering agents because of enhanced hCtr1 expression, as compared with their drug-sensitive counterparts. Such a preferential induction of hCtr1 expression in cDDP-resistant variants by copper chelation can be explained by the mammalian copper homeostasis regulatory mechanism. Enhanced cell-killing efficacy by a copper-lowering agent was also observed in animal xenografts bearing cDDP-resistant cells. Finally, by analyzing a public gene expression dataset, we found that ovarian cancer patients with elevated levels of hCtr1 in their tumors, but not ATP7A and ATP7B, had more favorable outcomes after platinum drug treatment than those expressing low hCtr1 levels. This study reveals the mechanistic basis for using copper chelation to overcome cDDP resistance in clinical investigations.

  15. Uranyl tris-(carbohydrazide) nitrate [UO{sub 2}((N{sub 2}H{sub 3}){sub 2}CO){sub 3}](NO{sub 3}){sub 2}. Synthesis, structure and properties

    Energy Technology Data Exchange (ETDEWEB)

    Leshok, Darya Y.; Samoilo, Alexander A.; Kirik, Sergei D. [Siberian Federal Univ., Krasnoyarsk (Russian Federation); Alekseenko, Vladimir N. [Federal Centre for Nuclear and Radiation Safety, Moscow (Russian Federation); Gavrilov, Peter M.; Alekseenko, Sergei N.; Dyachenko, Anton S. [Mining and Chemical Combine, Zheleznogorsk, Krasnoyarskii region (Russian Federation); Kondrasenko, Alexander A. [NMR Facility at Krasnoyarsk Multiaccesed Centre SB RAN, Krasnoyarsk (Russian Federation)

    2015-07-01

    Uranyl tris-(carbohydrazide) nitrate [UO{sub 2}((N{sub 2}H{sub 3}){sub 2}CO){sub 3}](NO{sub 3}){sub 2} was prepared by the reaction of water solution of dioxouranium(VI) nitrate UO{sub 2}(NO{sub 3}){sub 2}(H{sub 2}O){sub 6} with ethanol solution of carbohydrazide (N{sub 2}H{sub 3}){sub 2}CO in a molar ratio of 1 to 3 in an neutral medium. The substance was characterized by elemental, thermal analysis and IR and {sup 15}N MAS CP NMR spectroscopy. Ab initio crystal structure determination was carried out using X-ray powder diffraction techniques. The compound crystallizes in monoclinic lattice with unit cell parameters: a = 15.193(1) Aa, b = 12.005(1) Aa, c = 10.842(1) Aa, β = 109.15(1) , V = 1868.11 Aa{sup 3}, Z = 4, SG = Cc. The type of carbohydrazide coordination was additionally confirmed by {sup 15}N MAS CP NMR and IR spectroscopy. In the complex ion [UO{sub 2}((N{sub 2}H{sub 3}){sub 2}CO){sub 3}]{sup 2+} three carbohydrazide ligands coordinate to UO{sub 2}{sup 2+} through oxygen and nitrogen forming three five-membered chelate rings. The carbohydrazide rings are tuned to the equatorial plane of complex. The crystal structure consists of zig-zag chains of [UO{sub 2}((N{sub 2}H{sub 3}){sub 2}CO){sub 3}]{sup 2+} cations stretched along c-axis. The cations in the chain are linked by the hydrogen bonds between the cations themselves. The anions are located in the pores between chains and participate in hydrogen bonding between adjacent chains and additionally link the chain sections. The length of the chain section is 5.768 Aa and the angle between sections is 140 . The substance [UO{sub 2}((N{sub 2}H{sub 3}){sub 2}CO){sub 3}](NO{sub 3}){sub 2} is thermally stable up to 215 C and then decomposes with an explosion.

  16. Clinically approved iron chelators influence zebrafish mortality, hatching morphology and cardiac function.

    Directory of Open Access Journals (Sweden)

    Jasmine L Hamilton

    Full Text Available Iron chelation therapy using iron (III specific chelators such as desferrioxamine (DFO, Desferal, deferasirox (Exjade or ICL-670, and deferiprone (Ferriprox or L1 are the current standard of care for the treatment of iron overload. Although each chelator is capable of promoting some degree of iron excretion, these chelators are also associated with a wide range of well documented toxicities. However, there is currently very limited data available on their effects in developing embryos. In this study, we took advantage of the rapid development and transparency of the zebrafish embryo, Danio rerio to assess and compare the toxicity of iron chelators. All three iron chelators described above were delivered to zebrafish embryos by direct soaking and their effects on mortality, hatching and developmental morphology were monitored for 96 hpf. To determine whether toxicity was specific to embryos, we examined the effects of chelator exposure via intra peritoneal injection on the cardiac function and gene expression in adult zebrafish. Chelators varied significantly in their effects on embryo mortality, hatching and morphology. While none of the embryos or adults exposed to DFO were negatively affected, ICL -treated embryos and adults differed significantly from controls, and L1 exerted toxic effects in embryos alone. ICL-670 significantly increased the mortality of embryos treated with doses of 0.25 mM or higher and also affected embryo morphology, causing curvature of larvae treated with concentrations above 0.5 mM. ICL-670 exposure (10 µL of 0.1 mM injection also significantly increased the heart rate and cardiac output of adult zebrafish. While L1 exposure did not cause toxicity in adults, it did cause morphological defects in embryos at 0.5 mM. This study provides first evidence on iron chelator toxicity in early development and will help to guide our approach on better understanding the mechanism of iron chelator toxicity.

  17. A Novel Europium Chelate Coated Nanosphere for Time-Resolved Fluorescence Immunoassay.

    Directory of Open Access Journals (Sweden)

    Yifeng Shen

    Full Text Available A novel europium ligand 2,2',2'',2'''-(4,7-diphenyl-1,10-phenanthroline-2,9-diyl bis (methylene bis (azanetriyl tetra acetic acid (BC-EDTA was synthesized and characterized. It shows an emission spectrum peak at 610 nm when it is excited at 360 nm, with a large Stock shift (250 nm. It is covalently coated on the surface of a bare silica nanosphere containi free amino groups, using 1-ethyl-3-(3-dimethylaminopropyl carbodiimide hydrochloride and N-Hydroxysuccinimide. We also observed an interesting phenomenon that when BC-EDTA is labeled with a silica nanosphere, the chelate shows different excitation spectrum peaks of about 295 nm. We speculate that the carboxyl has a significant influence on its excitation spectrum. The BC-EDTA/Eu3+coated nanosphere could be used as a fluorescent probe for time-resolved fluorescence immunoassay. We labeled the antibody with the fluorescent nanosphere to develop a nanosphere based hepatitis B surface antigen as a time-resolved fluorescence immunoassay reagent, which is very easy to operate and eliminates potential contamination of Eu3+ contained in the environment. The analytical and functional sensitivities are 0.0037 μg/L and 0.08 μg/L (S/N≥2.0 respectively. The detection range is 0.08-166.67 μg/L, which is much wider than that of ELISA (0.2-5 μg/L. It is comparable to the commercial dissociation-enhanced lanthanide fluoro-immunoassay system (DELFIA reagents (0.2-145 μg/L. We propose that it can fulfill clinical applications.

  18. Luminescent properties of [UO{sub 2}(TFA){sub 2}(DMSO){sub 3}], a promising material for sensing and monitoring the uranyl ion

    Energy Technology Data Exchange (ETDEWEB)

    Martin-Ramos, Pablo; Silva, Manuela Ramos; Silva, Pedro S. Pereira da [Centro de Fisica da Universidade de Coimbra (CFisUC), Department of Physics, Universidade de Coimbra (Portugal); Costa, Ana L.; Melo, J. Sergio Seixas de [Centro de Quimica de Coimbra, Department of Chemistry, Universidade de Coimbra (Portugal); Pereira, Laura C.J. [Centro de Ciencias e Tecnologias Nucleares, Instituto Superior Tecnico, Universidade de Lisboa, Bobadela LRS (Portugal); Martin-Gil, Jesus, E-mail: pmr@unizar.es [Advanced Materials Laboratory, Escuela Tecnica Superior de Ingenierias Agrarias, University of Valladolid, Palencia (Spain)

    2016-03-15

    An uranyl complex [UO{sub 2}(TFA){sub 2}(DMSO){sub 3}] (TFA=deprotonated trifluoroacetic acid; DMSO=dimethyl sulfoxide) has been successfully synthesized by reacting UO{sub 2}(CH{sub 3}COO){sub 2} ·H{sub 2} O with one equivalent of (CF{sub 3} CO){sub 2} O and DMSO. The complex has been characterized by single-crystal X-ray diffraction, X-ray powder diffraction, elemental analysis, FTIR spectroscopy, thermal analysis and absorption and emission spectroscopies. The spectroscopic properties of the material make it suitable for its application in the sensing and monitoring of uranyl in the PUREX process. (author)

  19. MR imaging of lung ventilation with aerosolized Gadolinium-chelates; MR-Bildgebung der Lungenventilation mittels aerosolierter Gadolinium-Chelate

    Energy Technology Data Exchange (ETDEWEB)

    Haage, P.; Karaagac, S.; Spuentrup, E.; Guenther, R.W. [RWTH Aachen (Germany). Klinik fuer Radiologische Diagnostik; Adam, G. [Universitaetsklinikum Hamburg-Eppendorf (Germany). Abt. fuer Diagnostische und Interventionelle Radiologie

    2003-02-01

    Purpose: To evaluate the feasibility of magnetic resonance assessment of human lung ventilation with aerosolized Gd-chelates in healthy volunteers. Materials and Methods: Five healthy adults (mean age 37 years) were studied with a 1.5 T unit. The volunteers were instructed to inhale the aerosol through an airtight facial mask for 10 minutes. The aerosol was generated with a jet-type small particle nebulizer with attached heater. Ventilation imaging was performed using a respiration-gated dynamic T{sub 1}-weighted turbo spin echo sequence (T{sub R}=199 ms, T{sub E}=8.5 ms, 12 signal averages, slice thickness 10 mm). Pulmonary signal intensity changes were calculated before and after nebulization. Results: The investigation was successfully carried out in all volunteers. An acute or delayed allergic reaction to the aerosolized contrast medium was not observed. In 4 of 5 experiments (80%), a homogeneous signal intensity increase was readily visualized with an average signal increase of 35% after 10 minutes; in one experiment, the aerosol distribution was slightly heterogeneous. (orig.) [German] Ziel: Bestimmung der Durchfuehrbarkeit einer kernspintomographischen Darstellung der Lungenventilation mittels aerosolierter Gd-Chelate bei gesunden Probanden. Methoden: 5 Probanden (Durchschnittsalter 37 Jahre) wurden in einem 1,5T System untersucht. Die Probanden atmeten spontan aerosoliertes Gd-DTPA ueber eine Atemmaske fuer eine Dauer von 10 Minuten. Das Kontrastmittel-Aerosol wurde ueber einen leistungsfaehigen druckluftbetriebenen Vernebler generiert. Die Illustration der Ventilation erfolgte mit einer atemgegateten dynamischen T{sub 1}-gewichteten Turbo-Spin-Echosequenz. Zur Quantitifizerung der Lungenventilation wurden die Signalintensitaeten im Lungengewebe vor und nach Verneblung berechnet. Ergebnisse: Alle Untersuchungen wurden komplikationslos durchgefuehrt und beendet. Eine akute oder verzoegerte Kontrastmittelreaktion wurde nicht beobachtet. In 4 von 5

  20. Uranyl complexes formed with a para-t-butylcalix[4]arene bearing phosphinoyl pendant arms on the lower rim. Solid and solution studies

    Energy Technology Data Exchange (ETDEWEB)

    Ramirez, F. de M. [Instituto Nacional de Investigaciones Nucleares, La Marquesa, Ocoyoacac (Mexico). Dept. de Quimica; Varbanov, S. [Bulgarian Academy of Sciences, Sofia (Bulgaria). Inst. of Organic Chemistry with Center of Phytochemistry; Buenzli, J.C.G. [Ecole Polytechnique Federale de Lausanne (EPFL) (Switzerland). Inst. of Chemical Sciences and Engineering; Rivas-Silva, J.F.; Ocana-Bribiesca, M.A. [Instituto de Fisica de la BUAP, Puebla (Mexico); Cortes-Jacome, M.A.; Toledo-Antonio, J.A. [Instituto Mexicano del Petroleo/Programa de Ingenieria Molecular (Mexico)

    2012-07-01

    The current interest in functionalized calixarenes with phosphorylated pendant arms resides in their coordination ability towards f elements and capability towards actinide/rare earth separation. Uranyl cation forms 1:1 and 1:2 (M:L) complexes with a tetra-phosphinoylated p-tert-butylcalix[4]arene, B{sub 4}bL{sup 4}: UO{sub 2}(NO{sub 3}){sub 2}(B{sub 4}bL{sup 4}){sub n} . xH{sub 2}O (n = 1, x = 2, 1; n = 2, x = 6, 2). Spectroscopic data point to the inner coordination sphere of 1 containing one monodentate nitrate anion, one water molecule and the four phosphinoylated arms bound to UO{sub 2}{sup 2+} while in 2, uranyl is only coordinated to calixarene ligands. In both cases the U(VI) ion is 8-coordinate. Uranyl complexes display enhanced metal-centred luminescence due to energy transfer from the calixarene ligands; the luminescence decays are bi-exponential with associated lifetimes in the ranges 220 {mu}s < {tau}{sub s} < 250 {mu}s and 630 {mu}s < {tau}{sub L} < 640 {mu}s, pointing to the presence of two species with differently coordinated calixarene, as substantiated by a XPS study of U(4f{sub 5/2,7/2}), O(1s) and P(2p) levels on solid state samples. The extraction study of UO{sub 2}{sup 2+} cation and trivalent rare-earth (Y, La, Eu) ions from acidic nitrate media by B{sub 4}bL{sup 4} in chloroform shows the uranyl cation being much more extracted than rare earths. (orig.)

  1. Preliminary Assessment of Potential for Metal-Ligand Speciation in Aqueous Solution via the Liquid Sampling-Atmospheric Pressure Glow Discharge (LS-APGD) Ionization Source: Uranyl Acetate.

    Science.gov (United States)

    Zhang, Lynn X; Manard, Benjamin T; Powell, Brian A; Marcus, R Kenneth

    2015-07-21

    The determination of metals, including the generation of metal-ligand speciation information, is essential across a myriad of biochemical, environmental, and industrial systems. Metal speciation is generally affected by the combination of some form of chromatographic separation (reflective of the metal-ligand chemistry) with element-specific detection for the quantification of the metal composing the chromatographic eluent. Thus, the identity of the metal-ligand is assigned by inference. Presented here, the liquid sampling-atmospheric pressure glow discharge (LS-APGD) is assessed as an ionization source for metal speciation, with the uranyl ion-acetate system used as a test system. Molecular mass spectra can be obtained from the same source by simple modification of the sustaining electrolyte solution. Specifically, chemical information pertaining to the degree of acetate complexation of uranyl ion (UO2(2+)) is assessed as a function of pH in the spectral abundance of three metallic species: inorganic (nonligated) uranyl, UO2Ac(H2O)n(MeOH)m(+), and UO2Ac2(H2O)n(MeOH)(m)H(+) (n = 1, 2, 3, ...; m = 1, 2, 3, ...). The product mass spectra are different from what are obtained from electrospray ionization sources that have been applied to this system. The resulting relationships between the speciation and pH values have been compared to calculated concentrations of the corresponding uranyl species: UO2(2+), UO2Ac(+), UO2Ac2. The capacity for the LS-APGD to affect both atomic mass spectra and structurally significant spectra for organometallic complexes is a unique and potentially powerful combination.

  2. Uranyl ion interaction at the water/NiO(100) interface: A predictive investigation by first-principles molecular dynamic simulations

    Energy Technology Data Exchange (ETDEWEB)

    Sebbari, Karim [EDF-R and D, Departement Materiaux et Mecanique des Composants, Les Renardieres, Ecuelles, 77818 Moret Sur Loing (France); Institut de Physique Nucleaire d' Orsay, Universite Paris-Sud, CNRS UMR 8608, 15 rue Georges Clemenceau, Batiment 100, 91406 Orsay Cedex (France); Roques, Jerome; Simoni, Eric [Institut de Physique Nucleaire d' Orsay, Universite Paris-Sud, CNRS UMR 8608, 15 rue Georges Clemenceau, Batiment 100, 91406 Orsay Cedex (France); Domain, Christophe [EDF-R and D, Departement Materiaux et Mecanique des Composants, Les Renardieres, Ecuelles, 77818 Moret Sur Loing (France)

    2012-10-28

    The behavior of the UO{sub 2}{sup 2+} uranyl ion at the water/NiO(100) interface was investigated for the first time using Born-Oppenheimer molecular dynamic simulations with the spin polarized DFT +U extension. A water/NiO(100) interface model was first optimized on a defect-free five layers slab thickness, proposed as a reliable surface model, with an explicit treatment of the solvent. Water molecules are adsorbed with a well-defined structure in a thickness of about 4 A above the surface. The first layer, adsorbed on nickel atoms, remains mainly in molecular form but can partly dissociate at 293 K. Considering low acidic conditions, a bidentate uranyl ion complex was characterized on two surface oxygen species (arising from water molecules adsorption on nickel atoms) with d{sub U-O{sub a{sub d{sub s{sub o{sub r{sub p{sub t{sub i{sub o{sub n}}}}}}}}}}}=2.39 A. This complex is stable at 293 K due to iono-covalent bonds with an estimated charge transfer of 0.58 electron from the surface to the uranyl ion.

  3. Iron chelators can protect against oxidative stress through ferryl heme reduction.

    Science.gov (United States)

    Reeder, Brandon J; Hider, Robert C; Wilson, Michael T

    2008-02-01

    Iron chelators such as desferrioxamine have been shown to ameliorate oxidative damage in vivo. The mechanism of this therapeutic action under non-iron-overload conditions is, however, complex, as desferrioxamine has properties that can impact on oxidative damage independent of its capacity to act as an iron chelator. Desferrioxamine can act as a reducing agent to remove cytotoxic ferryl myoglobin and hemoglobin and has recently been shown to prevent the formation of a highly cytotoxic heme-to-protein cross-linked derivative of myoglobin. In this study we have examined the effects of a wide range of iron chelators, including the clinically used hydroxypyridinone CP20 (deferriprone), on the stability of ferryl myoglobin and on the formation of heme-to-protein cross-linking. We show that all hydroxypyridinones, as well as many other iron chelators, are efficient reducing agents of ferryl myoglobin. These compounds are also effective at preventing the formation of cytotoxic derivatives of myoglobin such as heme-to-protein cross-linking. These results show that the use of iron chelators in vivo may ameliorate oxidative damage under conditions of non-iron overload by at least two mechanisms. The antioxidant effects of chelators in vivo cannot, therefore, be attributed solely to iron chelation.

  4. MRI marrow observations in thalassemia: the effects of the primary disease, transfusional therapy, and chelation

    Energy Technology Data Exchange (ETDEWEB)

    Levin, T.L. [Department of Pediatric Radiology, Columbia-Presbyterian Medical Center, Babies and Children`s Hospital, New York, NY (United States); Sheth, S.S. [Department of Pediatrics, Columbia-Presbyterian Medical Center, Babies and Children`s Hospital, 3959 Broadway, New York, NY 10032 (United States); Ruzal-Shapiro, C. [Department of Pediatric Radiology, Columbia-Presbyterian Medical Center, Babies and Children`s Hospital, New York, NY (United States); Abramson, S. [Department of Radiology, Memorial Sloan-Kettering Cancer Center, 1275 York Avenue, New York, NY 10021 (United States); Piomelli, S. [Department of Pediatrics, Columbia-Presbyterian Medical Center, Babies and Children`s Hospital, 3959 Broadway, New York, NY 10032 (United States); Berdon, W.E. [Department of Pediatric Radiology, Columbia-Presbyterian Medical Center, Babies and Children`s Hospital, New York, NY (United States)

    1995-11-01

    The magnetic resonance bone marrow patterns in thalassemia were evaluated to determine changes produced by transfusion and chelation therapy. Thirteen patients had T1- and T2-weighted images of the spine, pelvis and femurs. Three received no therapy (age range 2.5-3 years). Three were ``hypertransfused`` (transfused to maintain a hemoglobin greater than 10 g/dl) and not chelated because of age (age range 6 months-8 years). Seven were ``hypertransfused`` and chelated (age range 12-35 years). Signal characteristics of marrow were compared with those of surrounding muscle and fat. Fatty marrow (isointense with subcutaneous fat) was compared with red marrow (hypointense to fat and slightly hyperintense to muscle). Marrow hypointense to muscle was identified as iron deposition within red marrow. The untreated group demonstrated signal consistent with red marrow throughout the central and peripheral skeleton. Hypertransfused but not chelated patients demonstrated marked iron deposition in the central and peripheral skeleton. Hypertransfused and chelated patients demonstrated iron deposition in the central skeleton and a mixed appearance of marrow in the peripheral skeleton. The MR appearance of marrow in thalassemia is a reflection of the patient`s transfusion and chelation therapy. Iron deposition occurs despite chelation therapy in sites of active red marrow. As red marrow retreats centrally with age, so does the pattern of iron deposition. The long-term biological effects of this iron deposition are unknown. (orig.). With 8 figs., 1 tab.

  5. Function of the iron-binding chelator produced by Coriolus versicolor in lignin biodegradation

    Institute of Scientific and Technical Information of China (English)

    WANG Lu; YAN WenChao; CHEN JiaChuan; HUANG Feng; GAO PeiJi

    2008-01-01

    An ultrafiltered low-molecular-weight preparation of chelating compounds was isolated from a wood-containing culture of the white-rot basidiomycete Coriolus versicolor. This preparation could chelate Fe3+ and reduce Fe3+ to Fe2+, demonstrating that the substance may serve as a ferric chelator,oxygen-reducing agent, and redox-cycling molecule, which would include functioning as the electron transport carrier in Fenton reaction. Lignin was treated with the iron-binding chelator and the changes in structure were investigated by 1H-NMR, 13C-NMR, difference spectrum caused by ionization under alkaline conditions and nitrobenzene oxidation. The results indicated that the iron-binding chelator could destroy the β-O-4 bonds in etherified lignin units and insert phenolic hydroxyl groups. The low-molecular-weight chelator secreted by C. versicolor resulted in new phenolic substructures in the lignin polymer, making it susceptible to attack by laccase or manganese peroxidase. Thus, the synergic action of the iron-binding chelator and the lignocellulolytic enzymes made the substrate more accessible to degradation.

  6. Chelating capture and magnetic removal of non-magnetic heavy metal substances from soil

    Science.gov (United States)

    Fan, Liren; Song, Jiqing; Bai, Wenbo; Wang, Shengping; Zeng, Ming; Li, Xiaoming; Zhou, Yang; Li, Haifeng; Lu, Haiwei

    2016-02-01

    A soil remediation method based on magnetic beneficiation is reported. A new magnetic solid chelator powder, FS@IDA (core-shell Fe3O4@SiO2 nanoparticles coated with iminodiacetic acid chelators), was used as a reactive magnetic carrier to selectively capture non-magnetic heavy metals in soil by chelation and removal by magnetic separation. FS@IDA was prepared via inorganic-organic and organic synthesis reactions that generated chelating groups on the surface of magnetic, multi-core, core-shell Fe3O4@SiO2 (FS) nanoparticles. These reactions used a silane coupling agent and sodium chloroacetate. The results show that FS@IDA could chelate the heavy metal component of Cd, Zn, Pb, Cu and Ni carbonates, lead sulfate and lead chloride in water-insoluble salt systems. The resulting FS@IDA-Cd and FS@IDA-Pb chelates could be magnetically separated, resulting in removal rates of approximately 84.9% and 72.2% for Cd and Pb, respectively. FS@IDA could not remove the residual heavy metals and those bound to organic matter in the soil. FS@IDA did not significantly alter the chemical composition of the soil, and it allowed for fast chelating capture, simple magnetic separation and facilitated heavy metal elution. FS@IDA could also be easily prepared and reprocessed.

  7. Recovery Properties of Polysulfone Hollow Fiber Chelating Membrane Modified with Thiourea for Mercury ( Ⅱ )

    Institute of Scientific and Technical Information of China (English)

    WANG Bing; XIAO Feng; HUANG Lei

    2007-01-01

    The adsorption isotherms of the polysulfone hollow fiber chelating membrane modified with thiourea as chelating groups for Hg2+ were determined. The effects of mobile phase conditions and the operating parameters on removal performance of the chelating membrane for Hg2+ were also investigated. The recovery of Hg2+ decreased at low pH and the optimum range of pH was from 6 to 7. The feed concentration effected on recovery of Hg2+ at the specified loading amount of Hg2+. The Hg2+ could be removed from different concentration feed solution by chelating membrane. The increase of feed flow rate led to slight decrease of recovery of Hg2+ at the specified loading amount of Hg2+. The chelating membrane could be operated at height feed flow rate and a large-scale removal of Hg2+ could be realized. With the increase of load amount, Hg2+ recovery decreased, but the saturation degree of chelating membrane increased. According to required recovery of Hg2+ and the saturation degree of chelating membrane, the optimum loading amount of Hg2+ should be selected in the actual removal of Hg2+.

  8. Generation, Fractionation, and Characterization of Iron-Chelating Protein Hydrolysate from Palm Kernel Cake Proteins.

    Science.gov (United States)

    Zarei, Mohammad; Ghanbari, Rahele; Tajabadi, Naser; Abdul-Hamid, Azizah; Bakar, Fatimah Abu; Saari, Nazamid

    2016-02-01

    Palm kernel cake protein was hydrolyzed with different proteases namely papain, bromelain, subtilisin, flavourzyme, trypsin, chymotrypsin, and pepsin to generate different protein hydrolysates. Peptide content and iron-chelating activity of each hydrolysate were evaluated using O-phthaldialdehyde-based spectrophotometric method and ferrozine-based colorimetric assay, respectively. The results revealed a positive correlation between peptide contents and iron-chelating activities of the protein hydrolysates. Protein hydrolysate generated by papain exhibited the highest peptide content of 10.5 mM and highest iron-chelating activity of 64.8% compared with the other hydrolysates. Profiling of the papain-generated hydrolysate by reverse phase high performance liquid chromatography fractionation indicated a direct association between peptide content and iron-chelating activity in most of the fractions. Further fractionation using isoelectric focusing also revealed that protein hydrolysate with basic and neutral isoelectric point (pI) had the highest iron-chelating activity, although a few fractions in the acidic range also exhibited good metal chelating potential. After identification and synthesis of papain-generated peptides, GGIF and YLLLK showed among the highest iron-chelating activities of 56% and 53%, whereas their IC50 were 1.4 and 0.2 μM, respectively.

  9. Function of the iron-binding chelator produced by Coriolus versicolor in lignin biodegradation

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    An ultrafiltered low-molecular-weight preparation of chelating compounds was isolated from a wood-containing culture of the white-rot basidiomycete Coriolus versicolor. This preparation could chelate Fe3+ and reduce Fe3+ to Fe2+, demonstrating that the substance may serve as a ferric chelator, oxygen-reducing agent, and redox-cycling molecule, which would include functioning as the electron transport carrier in Fenton reaction. Lignin was treated with the iron-binding chelator and the changes in structure were investigated by 1H-NMR, 13C-NMR, difference spectrum caused by ionization under alkaline conditions and nitrobenzene oxidation. The results indicated that the iron-binding chelator could destroy the β-O-4 bonds in etherified lignin units and insert phenolic hydroxyl groups. The low-molecular-weight chelator secreted by C. versicolor resulted in new phenolic substructures in the lignin polymer, making it susceptible to attack by laccase or manganese peroxidase. Thus, the synergic action of the iron-binding chelator and the lignocellulolytic enzymes made the substrate more acces- sible to degradation.

  10. Magnetic bead-based enzyme-chromogenic substrate system for ultrasensitive colorimetric immunoassay accompanying cascade reaction for enzymatic formation of squaric acid-iron(III) chelate.

    Science.gov (United States)

    Lai, Wenqiang; Tang, Dianping; Zhuang, Junyang; Chen, Guonan; Yang, Huanghao

    2014-05-20

    This work reports on a simple and feasible colorimetric immunoassay with signal amplification for sensitive determination of prostate-specific antigen (PSA, used as a model) at an ultralow concentration by using a new enzyme-chromogenic substrate system. We discovered that glucose oxidase (GOx), the enzyme broadly used in enzyme-linked immunosorbent assay (ELISA), has the ability to stimulate in situ formation of squaric acid (SQA)-iron(III) chelate. GOx-catalyzed oxidization of glucose leads to the formation of gluconic acid and hydrogen peroxide (H2O2). The latter can catalytically oxidize iron(II) to iron(III), which can rapidly (immunoassay protocol with GOx-labeled anti-PSA detection antibody can be designed for the detection of target PSA on capture antibody-functionalized magnetic immunosensing probe, monitored by recording the color or absorbance (λ = 468 nm) of the generated SQA-iron(III) chelate. The absorbance intensity shows to be dependent on the concentration of target PSA. A linear dependence between the absorbance and target PSA concentration is obtained under optimal conditions in the range from 1.0 pg mL(-1) to 30 ng mL(-1) with a detection limit (LOD) of 0.5 pg mL(-1) (0.5 ppt) estimated at the 3Sblank level. The sensitivity displays to be 3-5 orders of magnitude better than those of most commercialized human PSA ELISA kits. In addition, the developed colorimetric immunoassay was validated by assaying 12 human serum samples, receiving in good accordance with those obtained by the commercialized PSA ELISA kit. Importantly, the SQA-based immunosensing system can be further extended for the detection of other low-abundance proteins or biomarkers by controlling the target antibody.

  11. Study of Anti-Fatigue Effect in Rats of Ferrous Chelates Including Hairtail Protein Hydrolysates

    Science.gov (United States)

    Huang, Saibo; Lin, Huimin; Deng, Shang-gui

    2015-01-01

    The ability of ferrous chelates including hairtail protein hydrolysates to prevent and reduce fatigue was studied in rats. After hydrolysis of hairtail surimi with papain, the hairtail protein hydrolysates (HPH) were separated into three groups by range of relative molecular weight using ultrafiltration membrane separation. Hairtail proteins were then chelated with ferrous ions, and the antioxidant activity, the amino acid composition and chelation rate of the three kinds of ferrous chelates including hairtail protein hydrolysates (Fe-HPH) were determined. Among the three groups, the Fe-HPH chelate showing the best conditions was selected for the anti-fatigue animal experiment. For it, experimental rats were randomly divided into seven groups. Group A was designated as the negative control group given distilled water. Group B, the positive control group, was given glutathione. Groups C, D and E were designated as the Fe-HPH chelate treatment groups and given low, medium, and high doses, respectively. Group F was designated as HPH hydrolysate treatment group, and Group G was designated as FeCl2 treatment group. The different diets were orally administered to rats for 20 days. After that time, rats were subjected to forced swimming training after 1 h of gavage. Rats given Fe-FPH chelate had higher haemoglobin regeneration efficiency (HRE), longer exhaustive swimming time and higher SOD activity. Additionally, Fe-FPH chelate was found to significantly decrease the malondialdehyde content, visibly enhance the GSH-Px activity in liver and reduce blood lactic acid of rats. Fe-HPH chelate revealed an anti-fatigue effect, similar to or better than the positive control substance and superior to HPH or Fe when provided alone. PMID:26633476

  12. Isomerism in benzyl-DOTA derived bifunctional chelators: implications for molecular imaging.

    Science.gov (United States)

    Payne, Katherine M; Woods, Mark

    2015-02-18

    The bifunctional chelator IB-DOTA has found use in a range of biomedical applications given its ability to chelate many metal ions, but in particular the lanthanide(III) ions. Gd(3+) in particular is of interest in the development of new molecular imaging agents for MRI and is highly suitable for chelation by IB-DOTA. Given the long-term instability of the aryl isothiocyanate functional group we have used the more stable nitro derivative (NB-DOTA) to conduct a follow-up study of some of our previous work on the coordination chemistry of chelates of these BFCs. Using a combination of NMR and HPLC to study the Eu(3+) and Yb(3+) chelates of NB-DOTA, we have demonstrated that this ligand will produce two discrete regioisomeric chelates at the point at which the metal ion is introduced into the BFC. These regioisomers are defined by the position of the benzylic substituent on the macrocyclic ring: adopting an equatorial position either at the corner or the side of the [3333] ring conformation. These regioisomers are incapable of interconversion and are distinct, separate structures with different SAP/TSAP ratios. The side isomer exhibits an increased population of the TSAP isomer, pointing to more rapid water exchange kinetics in this regioisomer. This has potential ramifications for the use of these two regioisomers of Gd(3+)-BFC chelates in MRI applications. We have also found that, remarkably, there is little or no freedom of rotation about the first single bond extending from the macrocyclic ring to the benzylic substituent. Since this is the linkage through which the chelate is conjugated to the remainder of the molecular imaging probe, this result implies that there may be reduced local rotation of the Gd(3+) chelate within a molecular imaging probe. This implies that this type of BFC could exhibit higher relaxivities than other types of BFC.

  13. Study of Anti-Fatigue Effect in Rats of Ferrous Chelates Including Hairtail Protein Hydrolysates

    Directory of Open Access Journals (Sweden)

    Saibo Huang

    2015-12-01

    Full Text Available The ability of ferrous chelates including hairtail protein hydrolysates to prevent and reduce fatigue was studied in rats. After hydrolysis of hairtail surimi with papain, the hairtail protein hydrolysates (HPH were separated into three groups by range of relative molecular weight using ultrafiltration membrane separation. Hairtail proteins were then chelated with ferrous ions, and the antioxidant activity, the amino acid composition and chelation rate of the three kinds of ferrous chelates including hairtail protein hydrolysates (Fe-HPH were determined. Among the three groups, the Fe-HPH chelate showing the best conditions was selected for the anti-fatigue animal experiment. For it, experimental rats were randomly divided into seven groups. Group A was designated as the negative control group given distilled water. Group B, the positive control group, was given glutathione. Groups C, D and E were designated as the Fe-HPH chelate treatment groups and given low, medium, and high doses, respectively. Group F was designated as HPH hydrolysate treatment group, and Group G was designated as FeCl2 treatment group. The different diets were orally administered to rats for 20 days. After that time, rats were subjected to forced swimming training after 1 h of gavage. Rats given Fe-FPH chelate had higher haemoglobin regeneration efficiency (HRE, longer exhaustive swimming time and higher SOD activity. Additionally, Fe-FPH chelate was found to significantly decrease the malondialdehyde content, visibly enhance the GSH-Px activity in liver and reduce blood lactic acid of rats. Fe-HPH chelate revealed an anti-fatigue effect, similar to or better than the positive control substance and superior to HPH or Fe when provided alone.

  14. Chelate effects in sulfate binding by amide/urea-based ligands.

    Science.gov (United States)

    Jia, Chuandong; Wang, Qi-Qiang; Begum, Rowshan Ara; Day, Victor W; Bowman-James, Kristin

    2015-07-01

    The influence of chelate and mini-chelate effects on sulfate binding was explored for six amide-, amide/amine-, urea-, and urea/amine-based ligands. Two of the urea-based hosts were selective for SO4(2-) in water-mixed DMSO-d6 systems. Results indicated that the mini-chelate effect provided by a single urea group with two NH binding sites appears to provide enhanced binding over two amide groups. Furthermore, additional urea binding sites incorporated into the host framework appeared to overcome to some extent competing hydration effects with increasing water content.

  15. The Effect of Chelating Copolymer Additive on the Yttrium Iron Garnet Nanoparticle Formation

    Institute of Scientific and Technical Information of China (English)

    Wang; Cheng-chien

    2007-01-01

    1 Results Yttrium iron garnet (YIG) is a well-known ferromagnetic garnet material and has widely used in electronic devices[1].A new acrylic chelating polymer was developed to act as the additive of the preparation of YIG precursor in our previous study[2].The sintering temperature of YIG nanocrystal obtained by this YIG precursor (ACP) was magnificently descended from 1 000 to 600 ℃.In this study,we were further to study the effect of amount of chelating polymer and the compositions of chelating polyme...

  16. Expression of recombinant antibodies.

    Science.gov (United States)

    Frenzel, André; Hust, Michael; Schirrmann, Thomas

    2013-01-01

    Recombinant antibodies are highly specific detection probes in research, diagnostics, and have emerged over the last two decades as the fastest growing class of therapeutic proteins. Antibody generation has been dramatically accelerated by in vitro selection systems, particularly phage display. An increasing variety of recombinant production systems have been developed, ranging from Gram-negative and positive bacteria, yeasts and filamentous fungi, insect cell lines, mammalian cells to transgenic plants and animals. Currently, almost all therapeutic antibodies are still produced in mammalian cell lines in order to reduce the risk of immunogenicity due to altered, non-human glycosylation patterns. However, recent developments of glycosylation-engineered yeast, insect cell lines, and transgenic plants are promising to obtain antibodies with "human-like" post-translational modifications. Furthermore, smaller antibody fragments including bispecific antibodies without any glycosylation are successfully produced in bacteria and have advanced to clinical testing. The first therapeutic antibody products from a non-mammalian source can be expected in coming next years. In this review, we focus on current antibody production systems including their usability for different applications.

  17. Therapeutic Recombinant Monoclonal Antibodies

    Science.gov (United States)

    Bakhtiar, Ray

    2012-01-01

    During the last two decades, the rapid growth of biotechnology-derived techniques has led to a myriad of therapeutic recombinant monoclonal antibodies with significant clinical benefits. Recombinant monoclonal antibodies can be obtained from a number of natural sources such as animal cell cultures using recombinant DNA engineering. In contrast to…

  18. Recombinant renewable polyclonal antibodies.

    Science.gov (United States)

    Ferrara, Fortunato; D'Angelo, Sara; Gaiotto, Tiziano; Naranjo, Leslie; Tian, Hongzhao; Gräslund, Susanne; Dobrovetsky, Elena; Hraber, Peter; Lund-Johansen, Fridtjof; Saragozza, Silvia; Sblattero, Daniele; Kiss, Csaba; Bradbury, Andrew R M

    2015-01-01

    Only a small fraction of the antibodies in a traditional polyclonal antibody mixture recognize the target of interest, frequently resulting in undesirable polyreactivity. Here, we show that high-quality recombinant polyclonals, in which hundreds of different antibodies are all directed toward a target of interest, can be easily generated in vitro by combining phage and yeast display. We show that, unlike traditional polyclonals, which are limited resources, recombinant polyclonal antibodies can be amplified over one hundred million-fold without losing representation or functionality. Our protocol was tested on 9 different targets to demonstrate how the strategy allows the selective amplification of antibodies directed toward desirable target specific epitopes, such as those found in one protein but not a closely related one, and the elimination of antibodies recognizing common epitopes, without significant loss of diversity. These recombinant renewable polyclonal antibodies are usable in different assays, and can be generated in high throughput. This approach could potentially be used to develop highly specific recombinant renewable antibodies against all human gene products.

  19. A Nuclear Reactor and Chemical Processing Design for Production of Molybdenum-99 with Crystalline Uranyl Nitrate Hexahydrate Fuel

    Science.gov (United States)

    Stange, Gary Michael

    Medical radioisotopes are used in tens of millions of procedures every year to detect and image a wide variety of maladies and conditions in the human body. The most widely-used diagnostic radioisotope is technetium-99m, a metastable isomer of technetium-99 that is generated by the radioactive decay of molybdenum-99. For a number of reasons, the supply of molybdenum-99 has become unreliable and the techniques used to produce it have become unattractive. This has spurred the investigation of new technologies that avoid the use of highly enriched uranium to produce molybdenum-99 in the United States, where approximately half of the demand originates. The first goal of this research is to develop a critical nuclear reactor design powered by solid, discrete pins of low enriched uranium. Analyses of single-pin heat transfer and whole-core neutronics are performed to determine the required specifications. Molybdenum-99 is produced directly in the fuel of this reactor and then extracted through a series of chemical processing steps. After this extraction, the fuel is left in an aqueous state. The second goal of this research is to describe a process by which the uranium may be recovered from this spent fuel solution and reconstituted into the original fuel form. Fuel recovery is achieved through a crystallization step that generates solid uranyl nitrate hexahydrate while leaving the majority of fission products and transuranic isotopes in solution. This report provides background information on molybdenum-99 production and crystallization chemistry. The previously unknown thermal conductivity of the fuel material is measured. Following this is a description of the modeling and calculations used to develop a reactor concept. The operational characteristics of the reactor core model are analyzed and reported. Uranyl nitrate crystallization experiments have also been conducted, and the results of this work are presented here. Finally, a process flow scheme for uranium

  20. A membrane-specific tyrosinase chelate: the mitotic regulator?

    Science.gov (United States)

    Kharasch, J A

    1987-06-01

    Cancer's random, reversible, unstable transitions to "normal" structures imply their functional relation. Similar random, continuous, reversible oncogene "mutational transformation" also lacks a consistent hybrid. Positing cancer's "mutationally altered genotype" leads to medically foreign causes, qualities, inducers, suppressors, immune proteins, and viruses. Its random variation, however, opposes the functionally discrete, ordered, stable, irreversible hybrid variation and single-valued transforms of molecular genetics. There, "causal mutational operators" remain unspecified; only consistent single-valued DNA base and amino acid change, as "transform operand", are made explicit. A mitotically "blocked" (normal) and "unblocked" (malignant) stem cell "phenotype", operationally constructed from microscopic data, is therefore viewed within the homeostatic context of open-system enzyme-regulatory equilibrium. This functional, stochastic field distribution between "structurally bound" and "freely dividing" stem cell number discloses their putative regulatory mitotic-blocking factor. A tyrosinase complex, interacting by Cu2+-Fe2+ chelation with a proline hydroxylase divisional enzyme near stem cell ribosomes, maintains steady-state mitotic equilibrium. Based upon familiar medical, biochemical, and energy principles this confronts cancer's pigmentary-depigmentary signs, glycolytic metabolism, elevated serum tyrosinase, defective collagen production, exposed membrane binding sites, and tyrosine's recent growth control role.

  1. mer and fac isomerism in tris chelate diimine metal complexes.

    Science.gov (United States)

    Dabb, Serin L; Fletcher, Nicholas C

    2015-03-14

    In this perspective, we highlight the issue of meridional (mer) and facial (fac) orientation of asymmetrical diimines in tris-chelate transition metal complexes. Diimine ligands have long been the workhorse of coordination chemistry, and whilst there are now good strategies to isolate materials where the inherent metal centered chirality is under almost complete control, and systematic methodologies to isolate heteroleptic complexes, the conceptually simple geometrical isomerism has not been widely investigated. In systems where the two donor atoms are significantly different in terms of the σ-donor and π-accepting ability, the fac isomer is likely to be the thermodynamic product. For the diimine complexes with two trigonal planar nitrogen atoms there is much more subtlety to the system, and external factors such as the solvent, lattice packing and the various steric considerations play a delicate role in determining the observed and isolable product. In this article we discuss the possibilities to control the isomeric ratio in labile systems, consider the opportunities to separate inert complexes and discuss the observed differences in their spectroscopic properties. Finally we report on the ligand orientation in supramolecular systems where facial coordination leads to simple regular structures such as helicates and tetrahedra, but the ability of the ligand system to adopt a mer orientation enables self-assembled structures of considerable beauty and complexity.

  2. New method to estimate stability of chelate complexes

    CERN Document Server

    Grigoriev, F V; Romanov, A N; Kondakova, O A; Sulimov, V B

    2009-01-01

    A new method allowing calculation of the stability of chelate complexes with Mg2+ ion in water have been developed. The method is based on two-stage scheme for the complex formation. The first stage is the ligand transfer from an arbitrary point of the solution to the second solvation shell of the Mg2+ ion. At this stage the ligand is considered as a charged or neutral rigid body. The second stage takes into account disruption of coordinate bonds between Mg2+ and water molecules from the first solvation shell and formation of the bonds between the ligand and the Mg2+ ion. This effect is considered using the quantum chemical modeling. It has been revealed that the main contribution to the free energy of the complex formation is caused by the disruption/formation of the coordinate bonds between Mg2+, water molecules and the ligand. Another important contribution to the complex formation energy is change of electrostatic interactions in water solvent upon the ligand binding with Mg2+ ion. For all complexes under...

  3. Curcumin inhibits growth of Saccharomyces cerevisiae through iron chelation.

    Science.gov (United States)

    Minear, Steven; O'Donnell, Allyson F; Ballew, Anna; Giaever, Guri; Nislow, Corey; Stearns, Tim; Cyert, Martha S

    2011-11-01

    Curcumin, a polyphenol derived from turmeric, is an ancient therapeutic used in India for centuries to treat a wide array of ailments. Interest in curcumin has increased recently, with ongoing clinical trials exploring curcumin as an anticancer therapy and as a protectant against neurodegenerative diseases. In vitro, curcumin chelates metal ions. However, although diverse physiological effects have been documented for this compound, curcumin's mechanism of action on mammalian cells remains unclear. This study uses yeast as a model eukaryotic system to dissect the biological activity of curcumin. We found that yeast mutants lacking genes required for iron and copper homeostasis are hypersensitive to curcumin and that iron supplementation rescues this sensitivity. Curcumin penetrates yeast cells, concentrates in the endoplasmic reticulum (ER) membranes, and reduces the intracellular iron pool. Curcumin-treated, iron-starved cultures are enriched in unbudded cells, suggesting that the G(1) phase of the cell cycle is lengthened. A delay in cell cycle progression could, in part, explain the antitumorigenic properties associated with curcumin. We also demonstrate that curcumin causes a growth lag in cultured human cells that is remediated by the addition of exogenous iron. These findings suggest that curcumin-induced iron starvation is conserved from yeast to humans and underlies curcumin's medicinal properties.

  4. Anti-insulin antibody test

    Science.gov (United States)

    Insulin antibodies - serum; Insulin Ab test; Insulin resistance - insulin antibodies; Diabetes - insulin antibodies ... You appear to have an allergic response to insulin Insulin no longer seems to control your diabetes

  5. Temperature effects on the interaction mechanisms between the europium (III) and uranyl ions and zirconium diphosphate; Effets de la temperature sur les mecanismes d'interaction entre les ions europium (3) et uranyle et le diphosphate de zirconium

    Energy Technology Data Exchange (ETDEWEB)

    Finck, N

    2006-10-15

    Temperature should remain higher than 25 C in the near field environment of a nuclear waste repository for thousands years. In this context, the aim of this work is to study the temperature influence on the interaction mechanisms between europium (III) and uranyl ions and zirconium diphosphate, as well as the influence of a complexing medium (nitrate) on the sorption of the lanthanide. The experimental definition of the equilibria was achieved by combining a structural investigation with the macroscopic sorption data. Surface complexes were characterized at all temperatures (25 C to 90 C) by TRLFS experiments carried out on dry and in situ samples using an oven. This characterization was completed by XPS experiments carried out at 25 C on samples prepared at 25 C and 90 C. The reaction constants (surface hydration and cations sorption) were obtained by simulating the experimental data with the constant capacitance surface complexation model. The reaction constants temperature dependency allowed one to characterize thermodynamically the different reactions by application of the van't Hoff relation. The validity of this law was tested by performing microcalorimetric measurements of the sorption heat for both cations. (author)

  6. Click-to-Chelate: Development of Technetium and Rhenium-Tricarbonyl Labeled Radiopharmaceuticals

    Directory of Open Access Journals (Sweden)

    Thomas L. Mindt

    2013-03-01

    Full Text Available The Click-to-Chelate approach is a highly efficient strategy for the radiolabeling of molecules of medicinal interest with technetium and rhenium-tricarbonyl cores. Reaction of azide-functionalized molecules with alkyne prochelators by the Cu(I-catalyzed azide-alkyne cycloaddition (CuAAC; click reaction enables the simultaneous synthesis and conjugation of tridentate chelating systems for the stable complexation of the radiometals. In many cases, the functionalization of (biomolecules with the ligand system and radiolabeling can be achieved by convenient one-pot procedures. Since its first report in 2006, Click-to-Chelate has been applied to the development of numerous novel radiotracers with promising potential for translation into the clinic. This review summarizes the use of the Click-to-Chelate approach in radiopharmaceutical sciences and provides a perspective for future applications.

  7. Subclinical renal abnormalities in young thalassemia major and intermedia patients and its relation to chelation therapy

    Directory of Open Access Journals (Sweden)

    Amira A.M. Adly

    2014-10-01

    Conclusion: Subclinical renal affection can start earlier in TM patients compared to TI. Poor chelation is associated with early signs of renal affection. Periodic renal assessment of those patients is mandatory as they may be affected by hidden renal dysfunction.

  8. The Management of Iron Chelation Therapy: Preliminary Data from a National Registry of Thalassaemic Patients

    Science.gov (United States)

    Ceci, Adriana; Mangiarini, Laura; Felisi, Mariagrazia; Bartoloni, Franco; Ciancio, Angela; Capra, Marcello; D'Ascola, Domenico; Cianciulli, Paolo; Filosa, Aldo

    2011-01-01

    Thalassaemia and other haemoglobinopathies constitute an important health problem in Mediterranean countries, placing a tremendous emotional, psychological, and economic burden on their National Health systems. The development of new chelators in the most recent years had a major impact on the treatment of thalassaemia and on the quality of life of thalassaemic patients. A new initiative was promoted by the Italian Ministry of Health, establishing a Registry for thalassaemic patients to serve as a tool for the development of cost-effective diagnostic and therapeutic approaches and for the definition of guidelines supporting the most appropriate management of the iron-chelating therapy and a correct use of the available iron-chelating agents. This study represents the analysis of the preliminary data collected for the evaluation of current status of the iron chelation practice in the Italian thalassaemic population and describes how therapeutic interventions can widely differ in the different patients' age groups. PMID:21738864

  9. Absorption of nitric oxide into aqueous solutions of ferrous chelates accompanied by instantaneous reaction

    NARCIS (Netherlands)

    Demmink, J.F; vanGils, I.C.F.; Beenackers, A.A C M

    1997-01-01

    The absorption of nitric oxide (NO) into aqueous solutions of ferrous chelates of nitrilotriacetic acid (NTA), ethylene diaminetetraacetic acid (EDTA), hydroxyethylenediaminetriacetic acid (HEDTA), and diethylenetriaminepentaacetic acid (DTPA) was studied in a stirred cell reactor. Experimental cond

  10. CATALYTIC HYDROGENATION OF ACRYLATE ASMMETRIC Dd(Ⅱ)—CHELATING RESINS CONTAINING AMINO ACID LIGANDS

    Institute of Scientific and Technical Information of China (English)

    Wangying; WangHongzuo; 等

    1995-01-01

    The catalytic hydrogenation of palladium chelating resins containing chiral amino acid ligands based on lower crosslinked poly(chloroethyl acrylate) and some effects on the rate of hydrogenation were studied.

  11. Bifunctional chelates of RH-105 and AU199 as potential radiotherapeutic agents

    Energy Technology Data Exchange (ETDEWEB)

    Droege, P.

    1997-03-01

    Research is presented on new bifunctional chelating ligand systems with stability on the macroscopic and radiochemical levels. The synthesis of the following complexes are described: rhodium 105, palladium 109, and gold 198.

  12. Bifunctional chelating agent for the design and development of site specific radiopharmaceuticals and biomolecule conjugation strategy

    Science.gov (United States)

    Katti, Kattesh V.; Prabhu, Kandikere R.; Gali, Hariprasad; Pillarsetty, Nagavara Kishore; Volkert, Wynn A.

    2003-10-21

    There is provided a method of labeling a biomolecule with a transition metal or radiometal in a site specific manner to produce a diagnostic or therapeutic pharmaceutical compound by synthesizing a P.sub.2 N.sub.2 -bifunctional chelating agent intermediate, complexing the intermediate with a radio metal or a transition metal, and covalently linking the resulting metal-complexed bifunctional chelating agent with a biomolecule in a site specific manner. Also provided is a method of synthesizing the --PR.sub.2 containing biomolecules by synthesizing a P.sub.2 N.sub.2 -bifunctional chelating agent intermediate, complexing the intermediate with a radiometal or a transition metal, and covalently linking the resulting radio metal-complexed bifunctional chelating agent with a biomolecule in a site specific manner. There is provided a therapeutic or diagnostic agent comprising a --PR.sub.2 containing biomolecule.

  13. The Management of Iron Chelation Therapy: Preliminary Data from a National Registry of Thalassaemic Patients

    Directory of Open Access Journals (Sweden)

    Adriana Ceci

    2011-01-01

    Full Text Available Thalassaemia and other haemoglobinopathies constitute an important health problem in Mediterranean countries, placing a tremendous emotional, psychological, and economic burden on their National Health systems. The development of new chelators in the most recent years had a major impact on the treatment of thalassaemia and on the quality of life of thalassaemic patients. A new initiative was promoted by the Italian Ministry of Health, establishing a Registry for thalassaemic patients to serve as a tool for the development of cost-effective diagnostic and therapeutic approaches and for the definition of guidelines supporting the most appropriate management of the iron-chelating therapy and a correct use of the available iron-chelating agents. This study represents the analysis of the preliminary data collected for the evaluation of current status of the iron chelation practice in the Italian thalassaemic population and describes how therapeutic interventions can widely differ in the different patients' age groups.

  14. Iron chelation therapy in transfusion-dependent thalassemia patients: current strategies and future directions

    Directory of Open Access Journals (Sweden)

    Saliba AN

    2015-06-01

    Full Text Available Antoine N Saliba, Afif R Harb, Ali T Taher Department of Internal Medicine, Division of Hematology/Oncology, American University of Beirut, Beirut, Lebanon Abstract: Transfusional iron overload is a major target in the care of patients with transfusion-dependent thalassemia (TDT and other refractory anemias. Iron accumulates in the liver, heart, and endocrine organs leading to a wide array of complications. In this review, we summarize the characteristics of the approved iron chelators, deferoxamine, deferiprone, and deferasirox, and the evidence behind the use of each, as monotherapy or as part of combination therapy. We also review the different guidelines on iron chelation in TDT. This review also discusses future prospects and directions in the treatment of transfusional iron overload in TDT whether through innovation in chelation or other therapies, such as novel agents that improve transfusion dependence. Keywords: thalassemia, transfusion-dependent thalassemia, iron overload, iron chelation therapy, transfusion

  15. ORGANIC CHELATING REAGENT ON REDOX ADSORPTION OF ACTIVATED CARBON FIBER TOWARDS Au3+

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    Organic chelating reagent influences upon the redox adsorption of activated carbon fibertowards Au3- were systematically investigated. The experimental results indicated that the presenceof organic chelating reagent on activated carbon fiber strongly affects adsorption capacity ofactivated carbon fiber towards Au3+. The reduction-adsorption amount of Au3+ increased three timesby the presence of 8-quinolinol. Furthermore, The reduction-adsorption amount of Au3+ depended onthe pH value of adsorption and temperature.

  16. Synthesis, Characterization and Chelating Properties of 4-Butyrylsemicarbazone-1-phenyl-3-methyl-2-pyrazolin-5-one

    Directory of Open Access Journals (Sweden)

    J. D. Patel

    2010-01-01

    Full Text Available 4-Butyrylsemicarbazone-1-phenyl-3-methyl-2-pyrazolin-5-one (BUMP-SC was prepared and its metal chelates of Cu2+, Ni2+, Co2+, Mn2+, Fe2+, Fe3+, Cr3+, UO2 and OV were prepared. The ligands and its chelates were characterized by elemental analysis, metal:ligand (M:L stoichiometry, IR-electronic spectral studies and magnetic properties. The compounds also were screened for their antimicrobial activity.

  17. Role of the Symmetry of Multipoint Hydrogen Bonding on Chelate Cooperativity in Supramolecular Macrocyclization Processes.

    Science.gov (United States)

    Montoro-García, Carlos; Camacho-García, Jorge; López-Pérez, Ana M; Mayoral, María J; Bilbao, Nerea; González-Rodríguez, David

    2016-01-01

    Herein, we analyze the intrinsic chelate effect that multipoint H-bonding patterns exert on the overall energy of dinucleoside cyclic systems. Our results indicate that the chelate effect is regulated by the symmetry of the H-bonding pattern, and that the effective molarity is reduced by about three orders of magnitude when going from the unsymmetric ADD-DAA or DDA-AAD patterns to the symmetric DAD-ADA pattern.

  18. Chelation therapy and cardiovascular disease: connecting scientific silos to benefit cardiac patients.

    Science.gov (United States)

    Peguero, Julio G; Arenas, Ivan; Lamas, Gervasio A

    2014-08-01

    Medical practitioners have treated atherosclerotic disease with chelation therapy for over 50 years. Lack of strong of evidence led conventional practitioners to abandon its use in the 1960s and 1970s. This relegated chelation therapy to complementary and alternative medicine practitioners, who reported good anecdotal results. Concurrently, the epidemiologic evidence linking xenobiotic metals with cardiovascular disease and mortality gradually accumulated, suggesting a plausible role for chelation therapy. On the basis of the continued use of chelation therapy without an evidence base, the National Institutes of Health released a Request for Applications for a definitive trial of chelation therapy. The Trial to Assess Chelation Therapy (TACT) was formulated as a 2 × 2 factorial randomized controlled trial of intravenous EDTA-based chelation vs. placebo and high-dose oral multivitamins and multiminerals vs. oral placebo. The composite primary endpoint was death, reinfarction, stroke, coronary revascularization, or hospitalization for angina. A total of 1708 post-MI patients who were 50 years or older with a creatinine of 2.0 or less were enrolled and received 55,222 infusions of disodium EDTA or placebo with a median follow-up of 55 months. Patients were on evidence-based post-MI medications including statins. EDTA proved to be safe. EDTA chelation therapy reduced cardiovascular events by 18%, with a 5-year number needed to treat (NNT) of 18. Prespecified subgroup analysis revealed a robust benefit in patients with diabetes mellitus with a 41% reduction in the primary endpoint (5-year NNT = 6.5), and a 43% 5-year relative risk reduction in all-cause mortality (5-year NNT = 12). The magnitude of benefit is such that it suggests urgency in replication and implementation, which could, due to the excellent safety record, occur simultaneously.

  19. The iron chelator deferasirox protects mice from mucormycosis through iron starvation

    OpenAIRE

    2007-01-01

    Mucormycosis causes mortality in at least 50% of cases despite current first-line therapies. Clinical and animal data indicate that the presence of elevated available serum iron predisposes the host to mucormycosis. Here we demonstrate that deferasirox, an iron chelator recently approved for use in humans by the US FDA, is a highly effective treatment for mucormycosis. Deferasirox effectively chelated iron from Rhizopus oryzae and demonstrated cidal activity in vitro against 28 of 29 clinical...

  20. The Role of Chelation in the Treatment of Arsenic and Mercury Poisoning

    OpenAIRE

    Kosnett, Michael J

    2013-01-01

    Chelation for heavy metal intoxication began more than 70 years ago with the development of British anti-lewisite (BAL; dimercaprol) in wartime Britain as a potential antidote the arsenical warfare agent lewisite (dichloro[2-chlorovinyl]arsine). DMPS (unithiol) and DMSA (succimer), dithiol water-soluble analogs of BAL, were developed in the Soviet Union and China in the late 1950s. These three agents have remained the mainstay of chelation treatment of arsenic and mercury intoxication for mor...

  1. Monoclonal antibody "gold rush".

    Science.gov (United States)

    Maggon, Krishan

    2007-01-01

    The market, sales and regulatory approval of new human medicines, during the past few years, indicates increasing number and share of new biologics and emergence of new multibillion dollar molecules. The global sale of monoclonal antibodies in 2006 were $20.6 billion. Remicade had annual sales gain of $1 billion during the past 3 years and five brands had similar increase in 2006. Rituxan with 2006 sales of $4.7 billion was the best selling monoclonal antibody and biological product and the 6th among the top selling medicinal brand. It may be the first biologic and monoclonal antibody to reach $10 billion annual sales in the near future. The strong demand from cancer and arthritis patients has surpassed almost all commercial market research reports and sales forecast. Seven monoclonal antibody brands in 2006 had sales exceeding $1 billion. Humanized or fully human monoclonal antibodies with low immunogenicity, enhanced antigen binding and reduced cellular toxicity provide better clinical efficacy. The higher technical and clinical success rate, overcoming of technical hurdles in large scale manufacturing, low cost of market entry and IND filing, use of fully human and humanized monoclonal antibodies has attracted funds and resources towards R&D. Review of industry research pipeline and sales data during the past 3 years indicate a real paradigm shift in industrial R&D from pharmaceutical to biologics and monoclonal antibodies. The antibody bandwagon has been joined by 200 companies with hundreds of new projects and targets and has attracted billions of dollars in R&D investment, acquisitions and licensing deals leading to the current Monoclonal Antibody Gold Rush.

  2. Imaging Tumor Vasculature Noninvasively with Positron Emission Tomography and RGD Peptides Labeled with Copper 64 Using the Bifunctonal Chelates DOTA, Oxo-DO3A. and PCTA

    Directory of Open Access Journals (Sweden)

    Donald T.T. Yapp

    2013-06-01

    Full Text Available Two novel bifunctional chelates, 3,6,9,15-tetraazabicyclo[9.3.1]pentadeca-1(15,11,13-triene-3,6,9-triacetic acid (PCTA and 1-oxa-4,7,10-triazacyclododecane-4,7,10-triacetic acid (Oxo-DO3A, were found to radiolabel antibodies with copper 64 (64Cu well for positron emission tomography (PET. In this study, the same chelators were used to radiolabel peptides with 64Cu for PET imaging of angiogenesis. PCTA, Oxo-DO3A, and 1,4,7,10-tetraazacyclododecane-N,N‘,N“,N”’-tetraacetic acid (DOTA were conjugated to cyclic-(RGDyK, and their binding affinities were confirmed. Conditions for 64Cu radiolabeling were optimized for maximum yield and specific activity. The in vitro stability of the radiolabeled compounds was challenged with serum incubation. PET studies were carried out in a non-αvβ3-expressing tumor model to evaluate the compounds' specificity for proliferating tumor vasculature and their in vivo pharmacokinetics. The PCTA and Oxo-DO3A bioconjugates were labeled with 64Cu at higher effective specific activity and radiochemical yield than the DOTA bioconjugate. In the imaging studies, all the 64Cu bioconjugates could be used to visualize the tumor and the radiotracer uptake was blocked with cyclic-(RGDyK. Target uptake of each bioconjugate was similar, but differences in other tissues were observed. 64Cu-PCTA-RGD showed the best clearance from nontarget tissue and the highest tumor to nontarget ratios. PCTA was the most promising bifunctional chelate for 64Cu peptide imaging and warrants further investigation.

  3. Entangled Uranyl Organic Frameworks with (10,3)-b Topology and Polythreading Network: Structure, Luminescence, and Computational Investigation.

    Science.gov (United States)

    Liu, Chao; Gao, Chao-Ying; Yang, Weiting; Chen, Fang-Yuan; Pan, Qing-Jiang; Li, Jiyang; Sun, Zhong-Ming

    2016-06-06

    Two 3D uranyl organic frameworks (UOFs) with entangled structures, (HPhen)2[(UO2)2L2]·4.5H2O (1) and [(UO2)3(H2O)4L2]·6H2O (2), were synthesized using a rigid tripodal linker (4,4',4″-(phenylsilanetriyl)tribenzoic acid, H3L). Compound 1 represents a 2-fold interpenetrating UOF with the unique (10,3)-b topology. Compound 2 is composed of three interlocked sets of identical singlet networks and thus exhibits a rare 3D polythreading network with (3,4)-connected topology. These two compounds have been characterized by IR, UV-vis, and photoluminescent spectroscopy. A density functional theory (DFT) study on the model compounds of 1 and 2 shows good agreement of structural parameters and U═O stretching vibrational frequencies with experimental data. The experimentally measured absorption bands were well reproduced by the time-dependent DFT calculations.

  4. Experimental Results for Direct Electron Irradiation of a Uranyl Sulfate Solution: Bubble Formation and Thermal Hydraulics Studies

    Energy Technology Data Exchange (ETDEWEB)

    Chemerisov, Sergey [Argonne National Lab. (ANL), Argonne, IL (United States); Gromov, R. [Argonne National Lab. (ANL), Argonne, IL (United States); Makarashvili, Vakhtang [Argonne National Lab. (ANL), Argonne, IL (United States); Heltemes, Thad [Argonne National Lab. (ANL), Argonne, IL (United States); Sun, Zaijing [Argonne National Lab. (ANL), Argonne, IL (United States); Wardle, Kent E. [Argonne National Lab. (ANL), Argonne, IL (United States); Bailey, James [Argonne National Lab. (ANL), Argonne, IL (United States); Stepinski, Dominique [Argonne National Lab. (ANL), Argonne, IL (United States); Jerden, James [Argonne National Lab. (ANL), Argonne, IL (United States); Vandegrift, George F. [Argonne National Lab. (ANL), Argonne, IL (United States)

    2015-01-30

    In support of the development of accelerator-driven production of fission product Mo-99 as proposed by SHINE Medical Technologies, a 35 MeV electron linac was used to irradiate depleted-uranium (DU) uranyl sulfate dissolved in pH 1 sulfuric acid at average power densities of 6 kW, 12 kW, and 15 kW. During these irradiations, gas bubbles were generated in the solution due to the radiolytic decomposition of water molecules in the solution. Multiple video cameras were used to record the behavior of bubble generation and transport in the solution. Seven six-channel thermocouples were used to record temperature gradients in the solution from self-heating. Measurements of hydrogen and oxygen concentrations in a helium sweep gas were recorded by a gas chromatograph to estimate production rates during irradiation. These data are being used to validate a computational fluid dynamics (CFD) model of the experiment that includes multiphase flow and a custom bubble injection model for the solution region.

  5. Grain-Size Based Additivity Models for Scaling Multi-rate Uranyl Surface Complexation in Subsurface Sediments

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Xiaoying; Liu, Chongxuan; Hu, Bill X.; Hu, Qinhong

    2016-07-31

    The additivity model assumed that field-scale reaction properties in a sediment including surface area, reactive site concentration, and reaction rate can be predicted from field-scale grain-size distribution by linearly adding reaction properties estimated in laboratory for individual grain-size fractions. This study evaluated the additivity model in scaling mass transfer-limited, multi-rate uranyl (U(VI)) surface complexation reactions in a contaminated sediment. Experimental data of rate-limited U(VI) desorption in a stirred flow-cell reactor were used to estimate the statistical properties of the rate constants for individual grain-size fractions, which were then used to predict rate-limited U(VI) desorption in the composite sediment. The result indicated that the additivity model with respect to the rate of U(VI) desorption provided a good prediction of U(VI) desorption in the composite sediment. However, the rate constants were not directly scalable using the additivity model. An approximate additivity model for directly scaling rate constants was subsequently proposed and evaluated. The result found that the approximate model provided a good prediction of the experimental results within statistical uncertainty. This study also found that a gravel-size fraction (2 to 8 mm), which is often ignored in modeling U(VI) sorption and desorption, is statistically significant to the U(VI) desorption in the sediment.

  6. Adsorption characteristics of uranyl ions onto micelle surface for treatment of radioactive liquid wastes by micelle enhanced ultrafiltration technique

    Energy Technology Data Exchange (ETDEWEB)

    Lee, K. W.; Choi, W. K.; Jeong, K. H.; Lee, D. K.; Jeong, K. J. [KAERI, Taejon (Korea, Republic of)

    2001-10-01

    The objective of this investigation is to establish the rejection behavior of uranium bearing waste water by micelle enhanced ultrafiltration technique. An extensive experimental investigation was conducted with uranium only and uranium in the presence of electrolyte, utilizing ultrasfiltration stirred cell. The effects of experimental parameters such as solution pH and concentration of uranium on rejection were examined from the change of micelle concentration. The rejection dependence of the uranium was found to be a function of pH and uranium to surfactant concentration ratio. Over 95% removal was observed at pH 3 {approx} 5 and SDS concentration of 40 mM. In the presence of electrolytes, the rejection of uranium was observed to decrease significantly, the addition of cobalt ion showed more reduction than that obtained by presence of sodium and cesium ions on rejection of uranium. The rejection behavior was explained in terms of apparent distribution constants. The rejection efficiencies of uranyl ions was significantly affected by the chemical species of the given system. For all cases, the rejection was highly dependent on uranium complex species.

  7. Nanoscale UO{sub 2} and novel complex U(IV)-sulphate phase formation from electrolytically reduced uranyl sulphate solutions

    Energy Technology Data Exchange (ETDEWEB)

    Gil, D.; Malmbeck, R.; Spino, J.; Fanghaenel, T. [European Commission, Joint Research Centre, Inst. for Transuranium Elements, Karlsruhe (Germany); Dinnebier, R. [Max Planck Inst. for Solid State Research, Stuttgart (Germany)

    2010-07-01

    Three different processes have been explored to determine the ranges of U-concentration and acidity (pH-value) for nanocrystalline U{sub 2+x} precipitation from electrolytically reduced uranyl sulphate solutions. Precipitation of U{sub 2+x} nanoparticles aggregates was found to occur only in the narrow range of pH {proportional_to} 4.5 to 5 and for U-concentrations of {proportional_to} 10{sup -6} to 10{sup -7} M. The solid phase crystallized with the typical UO{sub 2}-fcc structure and with a crystallite size {<=} 3 nm. The average aggregate size was mostly {<=} 80 nm. At higher U-concentrations, ranging from [U] {proportional_to} 10{sup -1} M at pH {proportional_to} 1.5 to [U] {proportional_to} 5 x 10{sup -4} M at pH {proportional_to} 4.9, formation of microscale precipitates of a novel complex U(IV)-sulphate phase occurred, which was characterized by SEM/EDX-WDX, ICP-OES and XRD-powder diffraction. The crystal structure was identified with an orthorhombic cell (space group Cmca), with the following lattice parameters: a = 1.974(0)(2) nm, b = 1.3336(2) nm and c = 2.0643(2) nm. Further composition analyses indicated a basic sulphate hydrate of the type Na{sub 3}U(SO{sub 4}){sub 3}(OH).nH{sub 2}O. (orig.)

  8. Toward equatorial planarity about uranyl: synthesis and structure of tridentate nitrogen-donor {UO2}2+ complexes.

    Science.gov (United States)

    Copping, Roy; Jeon, Byoungseon; Pemmaraju, C Das; Wang, Shuao; Teat, Simon J; Janousch, Markus; Tyliszczak, Tolek; Canning, Andrew; Grønbech-Jensen, Niels; Prendergast, David; Shuh, David K

    2014-03-01

    The reaction of UO2Cl2·3THF with the tridentate nitrogen donor ligand 2,6-bis(2-benzimidazolyl)pyridine (H2BBP) in pyridine leads to the formation of three different complexes: [(UO2)(H2BBP)Cl2] (1), [(UO)2(HBBP)(Py)Cl] (2), and [(UO2)(BBP)(Py)2] (3) after successive deprotonation of H2BBP with a strong base. Crystallographic determination of 1-3 reveals that increased charge through ligand deprotonation and displacement of chloride leads to equatorial planarity about uranyl as well as a more compact overall coordination geometry. Near-Edge X-ray Absorption Fine Structure (NEXAFS) spectra of 1-3 at the U-4d edges have been recorded using a soft X-ray Scanning Transmission X-ray Microscope (STXM) and reveal the uranium 4d5/2 and 4d3/2 transitions at energies associated with uranium in the hexavalent oxidation state. First-principles Density Functional Theory (DFT) electronic structure calculations for the complexes have been performed to determine and validate the coordination characteristics, which correspond well to the experimental results.

  9. Antiphospholipid antibody syndrome.

    Science.gov (United States)

    Kutteh, William H; Hinote, Candace D

    2014-03-01

    Antiphospholipid antibodies (aPLs) are acquired antibodies directed against negatively charged phospholipids. Obstetric antiphospholipid antibody syndrome (APS) is diagnosed in the presence of certain clinical features in conjunction with positive laboratory findings. Obstetric APS is one of the most commonly identified causes of recurrent pregnancy loss. Thus, obstetric APS is distinguished from APS in other organ systems where the most common manifestation is thrombosis. Several pathophysiologic mechanisms of action of aPLs have been described. This article discusses the diagnostic and obstetric challenges of obstetric APS, proposed pathophysiologic mechanisms of APS during pregnancy, and the management of women during and after pregnancy.

  10. Optimization of chelators to enhance uranium uptake from tailings for phytoremediation.

    Science.gov (United States)

    Jagetiya, Bhagawatilal; Sharma, Anubha

    2013-04-01

    A greenhouse experiment was set up to investigate the ability of citric acid (CA), oxalic acid (OA), nitrilotriacetic acid (NTA) and EDTA for phytoremediation of uranium tailings by Indian mustard [Brassica juncea (L.) Czern. et Coss]. Uranium tailings were collected from Umra mining region and mixed with 75% of garden soil which yielded a 25:75 mixture. Prepared pots were divided into four sets and treated with following different concentrations - 0.1, 0.5, 2.5 and 12.5 mmol kg(-1) soil additions for each of the four chelators. Control pots which were not treated with chelators. Experiments were conducted in completely randomized block design with triplicates. The optimum concentrations of these chelators were found on the basis of biomass production, tolerance and accumulation potential. The data collected were expressed statistically. EDTA produced maximum growth depression whereas, minimum occurred in the case of NTA. Maximum U uptake (3.5-fold) in the roots occurred at 2.5 mmol of CA, while NTA proved to be the weakest for the same purpose. Severe toxicity in the form of reduced growth and plant death was recorded at 12.5 mmol of each chelator. Minimum growth inhibition produced by chelators occurred in NTA which was followed by OA, moderate in CA and maximum was traced in EDTA applications. Chelator strengthened U uptake in the present study follows the order: CA>EDTA>OA>NTA.

  11. ELECTED PROBLEMS RELATED TO ENVIRONMENTAL HEAVY METALS EXPOSURE AND CHELATION THERAPY

    Directory of Open Access Journals (Sweden)

    Anna Skoczyńska

    2010-09-01

    Full Text Available Background: Exposure to heavy metals leads to functional and metabolic disturbances and many of them are included in pathogenesis of common diseases (arterial hypertension, atherosclerosis, neurodegenerative processes. In this context new therapeutic and prophylactic strategies are necessary. Patients diagnosed with chronic heavy metals intoxication usually require chelation to increase mobilisation of metals from tissues and elimination of them via urine. Acute poisoning with toxic metal may be difficult to diagnosis, especially in case of accidental intoxication or suicidal intention. Patients also require chelation after causative factor is identified. Objectives: To describe some problems connected with toxicity of metals poisoning and to review pharmacologic therapies that could have a role in poisoning with metals. Methods: A review of the literature was carried out and expert opinion expressed. Results/conclusion: Chelation is a common therapy in case of poisoning with toxic metals but it is satisfied only partially. A combined therapy with structurally different chelators or long-term acting chelators could become viable alternatives in the future. A combined therapy with an antioxidant plus chelator may be a good choice in patients chronically poisoned with metals. Exposure to lead should be taken into account during estimation of global cardiovascular risk.

  12. The role of chelation in the treatment of arsenic and mercury poisoning.

    Science.gov (United States)

    Kosnett, Michael J

    2013-12-01

    Chelation for heavy metal intoxication began more than 70 years ago with the development of British anti-lewisite (BAL; dimercaprol) in wartime Britain as a potential antidote the arsenical warfare agent lewisite (dichloro[2-chlorovinyl]arsine). DMPS (unithiol) and DMSA (succimer), dithiol water-soluble analogs of BAL, were developed in the Soviet Union and China in the late 1950s. These three agents have remained the mainstay of chelation treatment of arsenic and mercury intoxication for more than half a century. Animal experiments and in some instances human data indicate that the dithiol chelators enhance arsenic and mercury excretion. Controlled animal experiments support a therapeutic role for these chelators in the prompt treatment of acute poisoning by arsenic and inorganic mercury salts. Treatment should be initiated as rapidly as possible (within minutes to a few hours), as efficacy declines or disappears as the time interval between metal exposure and onset of chelation increases. DMPS and DMSA, which have a higher therapeutic index than BAL and do not redistribute arsenic or mercury to the brain, offer advantages in clinical practice. Although chelation following chronic exposure to inorganic arsenic and inorganic mercury may accelerate metal excretion and diminish metal burden in some organs, potential therapeutic efficacy in terms of decreased morbidity and mortality is largely unestablished in cases of chronic metal intoxication.

  13. Hydroxypyri(mi)dine-based chelators as antidotes of toxicity due to aluminum and actinides.

    Science.gov (United States)

    Santos, M A; Esteves, M A; Chaves, S

    2012-01-01

    This review is focused on recent developments on hydroxypyri(mi)dines, as aluminum and actinide chelating agents to combat the toxicity due to accumulations of these metal ions in human body resulting from excessive metal exposure. After a brief update revision of the most common processes of aluminum (Al) exposure, as well as the associated toxicities and pathologies, we will focus on the current available Al chelators and future perspective as potential antidotes of Al toxicity. Due to the similarity between Al and Fe, a major emphasis is given to the hydroxypyridinone and hydroxypyrimidinone chelators, since they are analogues of the current iron chelators in clinical use (DFP and DFO). This review includes issues such as molecular design strategies and corresponding effects on the associated physico-chemical properties, lipo-hydrophilic balance, toxicity, in vivo bioassays and current clinical applications. The hydroxypyri(mi)dine chelators are also suitable for other hard metal ions, such as the radiotoxic actinides, and so a brief review is included on the applications of these chelators in actinides scavenging.

  14. Donor-Appended N,C-Chelate Organoboron Compounds: Influence of Donor Strength on Photochromic Behaviour.

    Science.gov (United States)

    Mellerup, Soren K; Yuan, Kang; Nguyen, Carmen; Lu, Zheng-Hong; Wang, Suning

    2016-08-22

    Recently, four-coordinated N,C-chelate organoboron compounds have been found to show many interesting photochemical transformations depending on the nature of their chelating framework. As such, the effect of substitution on the chelate ligand has been well-established and understood, but the impact of the aryl groups attached to the boron atom remains less clear. To investigate the effect of enhanced charge-transfer character, a series of new N,C-chelate organoboron compounds with donor-functionalized aryl groups have been synthesized and characterized using NMR, UV/Vis, and electrochemical methods. These compounds were found to possess bright and tunable charge-transfer luminescence which is dependent on the donor strength of the amino substituent. In addition, some of these compounds undergo photochromic switching, producing dark isomers of various colors. This work establishes that donor-functionalization of the aryl groups in N,C-chelate boron compounds is an effective strategy for tuning both the photophysical and photochemical properties of such systems. The new findings also help elucidate the influence of electronic structure on the photoreactivity of N,C-chelate organoboron compounds which appears to be as important as steric crowding around the boron atom.

  15. Effects of micronutrients deficiency and inoculation with arbuscular mycorrhizal fungi on chelator exudation by tomato root

    Directory of Open Access Journals (Sweden)

    E. Shirmohammadi

    2010-12-01

    Full Text Available Arbuscular mycorrhizal fungi (AMF can affect their host plants growth through nutrient uptake enhancement. Determination of chelators (siderophores and phytosiderophores in root leachates is of importance in order to account for the effects of AMF on nutrient uptake by plants. In this study, tomato plants were inoculated with either Glomus intraradices or Glomus etunicatum or left un-inoculated as non-mycorrhizal control, in pots containing sterile and acid washed perlite. Rorison’s nutrient solution harbouring three levels of Fe, Mn, Zn and Cu (full strength, half strength and without micronutrients was applied to the pots during three month- growth period. Root leachates were collected and total chelator concentration was quantified by titration with DTPA. Plant roots showed lower mycorrhizal colonization in this condition. The amounts of chelators produced by roots were significantly different in AMF species. In plants inoculated with G. intraradices, the highest chelator production occurred in the absence of micronutrients and in its half strength as well, but the micronutrient levels had no significant effect on chelator production in plants inoculated with G. etunicatum. In the absence of micronutrients, chelator production was higher in G.intraradices inoculated plants compared to the G. etunicatum ones.

  16. Antidiabetic effect of glucosaminic acid-cobalt (II chelate in streptozotocin-induced diabetes in mice

    Directory of Open Access Journals (Sweden)

    Talba T

    2011-04-01

    Full Text Available Tahirou Talba1, Xia Wen Shui1, Qinyuan Cheng1,2, Xin Tian21Key Laboratory of Food Processing Technology, 2School of Medicine and Pharmaceutics, Jiangnan University, Wuxi, Jiangsu, People's Republic of ChinaBackground: The purpose of this study was to assess the in vivo ability of glucosaminic acid-cobalt (II chelate to reduce glycemia.Methods: Different concentrations of chelate solution were administrated to mice with diabetes induced by streptozotocin. Daily oral administration of chelate solution 0.4 mL at various concentrations (0.32–0.4 g/mL led to reduction in water intake by the diabetic mice after 5 days of treatment, with a subsequent reduction in glucose levels observed 2 weeks later. Daily food intake was related to both chelate concentration as well as glycemia reduction. The food intake of mice treated with glucosaminic acid-cobalt (II chelate solution was 1.5-fold that of untreated mice.Keywords: glucosaminic acid, cobalt, chelate, streptozotocin, glycemia reduction

  17. Zinc glycine chelate absorption characteristics in Sprague Dawley rat.

    Science.gov (United States)

    Yue, M; Fang, S L; Zhuo, Z; Li, D D; Feng, J

    2015-06-01

    This study was conducted to investigate absorption characteristics of zinc glycine chelate (Zn-Gly) by evaluating tissues zinc status and the expression of zinc transporters in rats. A total of 24 male rats were randomly allocated to three treatments and administered either saline or 35 mg Zn/kg body weight from zinc sulphate (ZnSO4 ) or Zn-Gly by feeding tube separately. Four rats per group were slaughtered and tissues were collected at 2 and 6 h after gavage respectively. Our data showed that Zn-Gly did more effectively in increasing (p < 0.05) serum zinc levels, and the activities of serum and liver alkaline phosphatase (ALP) and liver Cu/Zn superoxide dismutase (Cu/Zn SOD) at 2 and 6 h. By 2 h after the zinc load, the mRNA and protein abundance of intestinal metallothionein1 (MT1) and zinc transporter SLC30A1 (ZnT1) were higher (p < 0.05), and zinc transporter SLC39A4 (Zip4) lower (p < 0.05) in ZnSO4 compared to other groups. Zinc transporter SLC39A5 (Zip5) mRNA expression was not zinc responsive, but Zip5 protein abundance was remarkably (p < 0.05) increased in ZnSO4 2 h later. Overall, our results indicated that in short-term periods, Zn-Gly was more effective in improving body zinc status than ZnSO4 , and ZnSO4 did more efficiently on the regulation of zinc transporters in small intestine.

  18. Anti-cartilage antibody.

    Science.gov (United States)

    Greenbury, C L; Skingle, J

    1979-08-01

    Antibody to cartilage has been demonstrated by indirect immunofluorescence on rat trachea in the serum of about 3% of 1126 patients with rheumatoid arthritis. Titres ranged from 1:20 to 1:640. The antibody was not found in 284 patients with primary or secondary osteoarthritis or in 1825 blood donors, nor, with the exception of two weak reactors, in 1314 paraplegic patients. In most cases the antibody appears to be specific for native type II collagen. Using this as an antigen in a haemagglutination test 94% of anti-cartilage sera were positive, whereas among 100 rheumatoid control sera there were only three weak positives. More than 80% of patients with antibody had some erosion of articular cartilage, but there was no correlation with age, sex, duration of disease, nor any recognisable clinical event or change.

  19. Antithyroid microsomal antibody

    Science.gov (United States)

    ... to confirm the cause of thyroid problems, including Hashimoto thyroiditis . The test is also used to find ... positive test may be due to: Granulomatous thyroiditis Hashimoto thyroiditis High levels of these antibodies have also ...

  20. Serum herpes simplex antibodies

    Science.gov (United States)

    ... 2. HSV-1 most often causes cold sores (oral herpes). HSV-2 causes genital herpes. How the Test ... whether a person has ever been infected with oral or genital herpes . It looks for antibodies to herpes simplex virus ...

  1. Nanoparticle iron chelators: a new therapeutic approach in Alzheimer disease and other neurologic disorders associated with trace metal imbalance.

    Science.gov (United States)

    Liu, Gang; Men, Ping; Harris, Peggy L R; Rolston, Raj K; Perry, George; Smith, Mark A

    2006-10-09

    Accumulating evidence suggests that oxidative stress may be a major etiologic factor in initiating and promoting neurodegeneration in Alzheimer disease. Contributing to this, there is a dyshomeostasis of metal ions in Alzheimer disease with abnormally high levels of redox-active metals, particularly iron, in affected areas of the brain. Although it is unclear whether metal excesses are the sole cause of oxidative stress and neurodegeneration or a by-product of neuronal loss, the finding that metal chelators can partially solubilize amyloid-beta deposits in Alzheimer disease suggests a promising therapeutic role for chelating agents. However, the blood-brain barrier and toxicity of known chelators limit their utility. In this study, we suggest that covalent conjugation of iron chelators with nanoparticles may help overcome the limitations in blood-brain barrier permeability of existing chelation therapy. Using in vitro studies, we have shown that a chelator-nanoparticle system and the chelator-nanoparticle system complexed with iron, when incubated with human plasma, preferentially adsorb apolipoprotein E and apolipoprotein A-I, that would facilitate transport into and out of the brain via mechanisms used for transporting low-density lipoprotein. Our studies suggest a unique approach, utilizing nanoparticles, to transport chelators and chelator-metal complexes in both directions across the blood-brain barrier, thus providing safer and more effective chelation treatment in Alzheimer disease and other neurodegenerative diseases.

  2. Direct 99mTc labeling of monoclonal antibodies: radiolabeling and in vitro stability.

    Science.gov (United States)

    Garron, J Y; Moinereau, M; Pasqualini, R; Saccavini, J C

    1991-01-01

    Direct labeling involves 99mTc binding to different donor groups on the protein, giving multiple binding sites of various affinities resulting in an in vivo instability. The stability has been considerably improved by activating the antibody using a controlled reduction reaction (using 2-aminoethanethiol). This reaction generates sulfhydryl groups, which are known to strongly bind 99mTc. The direct 99mTc antibody labeling method was explored using whole antibodies and fragments. Analytical methods were developed for routine evaluation of radiolabeling yield and in vitro stability. Stable direct antibody labeling with 99mTc requires the generation of sulfhydryl groups, which show high affinity binding sites for 99mTc. Such groups are obtained with 2-aminoethanethiol (AET), which induces the reduction of the intrachain or interchain disulfide bond, with no structural deterioration or any loss of immunobiological activity of the antibody. The development of fast, reliable analytical methods has made possible the qualitative and quantitative assessment of technetium species generated by the radiolabeling process. Labeling stability is determined by competition of the 99mTc-antibody bond with three ligands, Chelex 100 (a metal chelate-type resin), free DTPA solution and 1% HSA solution. Very good 99mTc-antibody stability is obtained with activated IgG (IgGa) and Fab' fragment, which makes these substances possible candidates for immunoscintigraphy use.

  3. Kinetic of liquid-liquid extraction for uranyl nitrate and actinides (III) and lanthanides (III) nitrates by amide extractants; Cinetique d`extraction liquide-liquide du nitrate d`uranyle et des nitrates d`actinides (III) et de lanthanides (III) par des extractants a fonction amide

    Energy Technology Data Exchange (ETDEWEB)

    Toulemonde, V. [CEA Centre d`Etudes Nucleaires de Saclay, 91 -Gif-sur-Yvette (France)]|[CEA Centre d`Etudes de la Vallee du Rhone, 30 -Marcoule (France). Dept. d`Exploitation du Retraitement et de Demantelement

    1995-12-20

    The kinetics of liquid-liquid extraction by amide extractants have been investigated for uranyl nitrate (monoamide extractants), actinides (III) and lanthanides (III) nitrates (diamide extractants). The transfer of the metallic species from the aqueous phase to the organic phase was studied using two experimental devices: ARMOLLEX (Argonne Modified Lewis cell for Liquid Liquid Extraction) and RSC (Rotating Stabilized Cell). The main conclusions are: for the extraction of uranyl nitrate by DEHDMBA monoamide, the rate-controlling step is the complexation of the species at the interface of the two liquids. Thus, an absorption-desorption (according to Langmuir theory) reaction mechanism was proposed; for the extraction of actinides (III) and lanthanides (III) nitrates in nitric acid media by DMDBTDMA diamide, the kinetic is also limited by interfacial reactions. The behavior of Americium and Europium is very similar as fare as their reaction kinetics are concerned. (author). 89 refs.

  4. Chemically optimized antimyosin Fab conjugates with chelating polymers: importance of the nature of the protein-polymer single site covalent bond for biodistribution and infarction localization.

    Science.gov (United States)

    Trubetskoy, V S; Narula, J; Khaw, B A; Torchilin, V P

    1993-01-01

    Murine antimyosin Fab fragment was conjugated with 111In-labeled N-terminal-modified DTPA-polylysine using three bifunctional reagents: N-hydroxysuccinimide esters of 3-(2-pyridyldithio)propionic acid (SPDP conjugate), 4-(maleimidomethyl)cyclohexanecarboxylic acid (SMCC conjugate) and bromoacetic acid (BrAc conjugate) for potential localization of experimental myocardial infarction. Using various antibody preparations and a rabbit acute myocardial infarction model the following parameters were observed: (1) an in vitro antigen binding activity of SPDP conjugate = SMCC conjugate > BrAc conjugate, (2) a blood clearance rate of SPDP conjugate > BrAc conjugate > SMCC conjugate, (3) a liver and splenic accumulation of SPDP conjugate > BrAc conjugate > SMCC conjugate, and (4) the infarcted tissue activity showed an accumulation of SMCC conjugate > SPDP conjugate > BrAc conjugate. This study exemplifies the importance of rational chemical design of antimyosin Fab-chelating polymer conjugate for improved target tissue localization in vivo.

  5. CARDIAC FUNCTION AND IRON CHELATION IN THALASSEMIA MAJOR AND INTERMEDIA: A REVIEW OF THE UNDERLYING PATHOPHYSIOLOGY AND APPROACH TO CHELATION MANAGEMENT

    Directory of Open Access Journals (Sweden)

    Athanasios Aessopos

    2009-07-01

    Full Text Available Heart disease is the leading cause of mortality and one of the main causes of morbidity in beta-thalassemia. Patients with homozygous thalassemia may have either a severe phenotype which is usually transfusion dependent or a milder form that is thalassemia intermedia.  The two main factors that determine cardiac disease in homozygous β thalassemia are the high output state that results from chronic tissue hypoxia, hypoxia-induced compensatory reactions and iron overload.  The high output state playing a major role in thalassaemia intermedia and the iron load being more significant in the major form. Arrhythmias, vascular involvement that leads to an increased pulmonary vascular resistance and an increased systemic vascular stiffness and valvular abnormalities also contribute to the cardiac dysfunction in varying degrees according to the severity of the phenotype.  Endocrine abnormalities, infections, renal function and medications can also play a role in the overall cardiac function.  For thalassaemia major, regular and adequate blood transfusions and iron chelation therapy are the mainstays of management. The approach to thalassaemia intermedia, today, is aimed at monitoring for complications and initiating, timely, regular transfusions and/or iron chelation therapy.  Once the patients are on transfusions, then they should be managed in the same way as the thalassaemia major patients.  If cardiac manifestations of dysfunction are present in either form of thalassaemia, high pre transfusion Hb levels need to be maintained in order to reduce cardiac output and appropriate intensive chelation therapy needs to be instituted.  In general recommendations on chelation, today, are usually made according to the Cardiac Magnetic Resonance findings, if available.  With the advances in the latter technology and the ability to tailor chelation therapy according to the MRI findings as well as the availability of three iron chelators, together with

  6. New Insights into the Functional Behavior of Antibodies as Revealed by Binding Studies on an Anti-Uranium Monoclonal Antibody

    Energy Technology Data Exchange (ETDEWEB)

    Blake, Diane A.; Xia Li; Haini Yu; Blake, Robert C.

    2004-03-17

    As part of an ongoing effort to develop immunoassays for chelated uranium(VI) on a hand-held flow fluorimeter, an anti-uranium monoclonal antibody designated as 8A11 was fluorescently labeled using two different strategies. When 8A11 was coupled via reactive lysines to either ALEXATM 488 or Cy5TM, the resulting fluorescent antibody conjugate exhibited positive cooperativity in the presence of its antigen, U(VI) chelated with 2,9-dicarboxy-1,10-phenanthroline (U(VI)-DCP). That is, when one of the two binding sites on the covalently modified 8A11 was occupied with bound antigen, the affinity of the remaining site on the antibody for U(VI)-DCP appeared to increase. Unmodified 8A11 bound U(VI)-DCP with the expected hyperbolic dependence on the concentration of antigen, consistent with independent and equal binding of ligand at both sites. Proteolytic cleavage of the fluorescently conjugated 8A11 to produce the fluorescent monovalent Fab fragment yielded an active preparation that now bound U(VI)-DCP with no evidence of positive cooperativity. Although, in principle, any divalent antibody has the potential to exhibit positive cooperativity in its binding interactions with its antigen, very little literature precedent for this type of behavior exists. Native 8A11 was also noncovalently labeled with highly fluorescent ZENONTM reagents. These reagents are fluorescently-labeled Fab fragments of goat anti-mouse antibodies that bind to the Fc portion of 8A11. These high-affinity, monovalent fluorescent reagents permitted the intact 8A11 mouse antibody to be labeled in situ with no covalent modifications. Incubation of the 8A11 with ZENON 647 produced a fluorescent protein complex that showed an 8-fold higher affinity for U(VI)-DCP than did the free 8A11 alone. Again, very few literature precedents exist for this phenomenon, where agents that bind to the Fc portion of an intact antibody change the affinity of the antibody for the antigen at the structurally distant Fab portion

  7. Heparin-Induced Thrombocytopenia Antibody Test

    Science.gov (United States)

    ... Global Sites Search Help? Heparin-induced Thrombocytopenia PF4 Antibody Share this page: Was this page helpful? Also known as: Heparin-PF4 Antibody; HIT Antibody; HIT PF4 Antibody; Heparin Induced Antibody; ...

  8. The system uranyl nitrate-dietyl ether-water. Extraction by water in spray and packed columns from uranyl nitrate-either solutions; El sistema nitrato de uranilo-eter dietilico-agua, extraccion de nitrato de uranilo con agua a partir de disoluciones etereas en columnas de pulverizacion y de relleno

    Energy Technology Data Exchange (ETDEWEB)

    Perez Luina, A.; Gutierrez Jodra, L.

    1960-07-01

    This paper is a continuation of the one published in Chemical Engineering Progress. Symposium Series, 50, n. 12, 127 (1954). New runs for spray columns, are given and other concentrations in uranyl nitrate for the packed columns. New correlations for the overall H.T.U. are also given. The individual H.T.U. have been grapycally calculated and show that the film resistances have similar values, being independent of the concentration of the ether phase. (Author) 24 refs.

  9. [New antibodies in cancer treatment].

    Science.gov (United States)

    Pestalozzi, B C; Knuth, A

    2004-09-22

    Since the development of hybridoma technology in 1975 monoclonal antibodies with pre-defined specificity can be produced. Only twenty years later did it become possible to make therapeutic use of monoclonal antibodies in oncology. To this end it was necessary to attach the antigen-binding site of a mouse antibody onto the scaffold of a human antibody molecule. Such chimeric or "humanized" antibodies may be used in passive immunotherapy without eliciting an immune response. Rituximab and trastuzumab are such humanized antibodies. They are used today routinely in the treatment of malignant lymphoma and breast cancer, respectively. These antibodies are usually used in combination with conventional cytostatic anticancer drugs.

  10. Engineering antibodies for cancer therapy.

    Science.gov (United States)

    Boder, Eric T; Jiang, Wei

    2011-01-01

    The advent of modern antibody engineering has led to numerous successes in the application of these proteins for cancer therapy in the 13 years since the first Food and Drug Administration approval, which has stimulated active interest in developing more and better drugs based on these molecules. A wide range of tools for discovering and engineering antibodies has been brought to bear on this challenge in the past two decades. Here, we summarize mechanisms of monoclonal antibody therapeutic activity, challenges to effective antibody-based treatment, existing technologies for antibody engineering, and current concepts for engineering new antibody formats and antibody alternatives as next generation biopharmaceuticals for cancer treatment.

  11. Modular strategy for the construction of radiometalated antibodies for positron emission tomography based on inverse electron demand Diels-Alder click chemistry.

    Science.gov (United States)

    Zeglis, Brian M; Mohindra, Priya; Weissmann, Gabriel I; Divilov, Vadim; Hilderbrand, Scott A; Weissleder, Ralph; Lewis, Jason S

    2011-10-19

    A modular system for the construction of radiometalated antibodies was developed based on the bioorthogonal cycloaddition reaction between 3-(4-benzylamino)-1,2,4,5-tetrazine and the strained dienophile norbornene. The well-characterized, HER2-specific antibody trastuzumab and the positron emitting radioisotopes (64)Cu and (89)Zr were employed as a model system. The antibody was first covalently coupled to norbornene, and this stock of norbornene-modified antibody was then reacted with tetrazines bearing the chelators 1,4,7,10-tetraazacyclo-dodecane-1,4,7,10-tetraacetic acid (DOTA) or desferrioxamine (DFO) and subsequently radiometalated with (64)Cu and (89)Zr, respectively. The modification strategy is simple and robust, and the resultant radiometalated constructs were obtained in high specific activity (2.7-5.3 mCi/mg). For a given initial stoichiometric ratio of norbornene to antibody, the (64)Cu-DOTA- and (89)Zr-DFO-based probes were shown to be nearly identical in terms of stability, the number of chelates per antibody, and immunoreactivity (>93% in all cases). In vivo PET imaging and acute biodistribution experiments revealed significant, specific uptake of the (64)Cu- and (89)Zr-trastuzumab bioconjugates in HER2-positive BT-474 xenografts, with little background uptake in HER2-negative MDA-MB-468 xenografts or other tissues. This modular system-one in which the divergent point is a single covalently modified antibody stock that can be reacted selectively with various chelators-will allow for both greater versatility and more facile cross-comparisons in the development of antibody-based radiopharmaceuticals.

  12. UO₂²⁺ uptake by proteins: understanding the binding features of the super uranyl binding protein and design of a protein with higher affinity.

    Science.gov (United States)

    Odoh, Samuel O; Bondarevsky, Gary D; Karpus, Jason; Cui, Qiang; He, Chuan; Spezia, Riccardo; Gagliardi, Laura

    2014-12-17

    The capture of uranyl, UO2(2+), by a recently engineered protein (Zhou et al. Nat. Chem. 2014, 6, 236) with high selectivity and femtomolar sensitivity has been examined by a combination of density functional theory, molecular dynamics, and free-energy simulations. It was found that UO2(2+) is coordinated to five carboxylate oxygen atoms from four amino acid residues of the super uranyl binding protein (SUP). A network of hydrogen bonds between the amino acid residues coordinated to UO2(2+) and residues in its second coordination sphere also affects the protein's uranyl binding affinity. Free-energy simulations show how UO2(2+) capture is governed by the nature of the amino acid residues in the binding site, the integrity and strength of the second-sphere hydrogen bond network, and the number of water molecules in the first coordination sphere. Alteration of any of these three factors through mutations generally results in a reduction of the binding free energy of UO2(2+) to the aqueous protein as well as of the difference between the binding free energies of UO2(2+) and other ions (Ca(2+), Cu(2+), Mg(2+), and Zn(2+)), a proxy for the protein's selectivity over these ions. The results of our free-energy simulations confirmed the previously reported experimental results and allowed us to discover a mutant of SUP, specifically the GLU64ASP mutant, that not only binds UO2(2+) more strongly than SUP but that is also more selective for UO2(2+) over other ions. The predictions from the computations were confirmed experimentally.

  13. Establishment of the conditions for the determination of the concentration of the uranyl ion in perchloric media by Fluorescence; Establecimiento de las condiciones para la determinacion de la concentracion del ion uranilo en medio perclorico por Fluorescencia

    Energy Technology Data Exchange (ETDEWEB)

    Contreras R, A.; Ordonez R, E.; Fernandez V, S.M. [ININ, 52045 Ocoyoacac, Estado de Mexico (Mexico)]. e-mail: contraida@yahoo.com.mx

    2004-07-01

    The influence of the p H is reported in the spectra of luminescence of the ion uranyl in sodium perchlorate 2M. The best spectra were observed to ph <3 that to neutral and basic p Hs this is explained by the present species. They were carried out four calibration curves for the uranyl in perchloric acid media, taking into account the area under the curve, the maximum height of two characteristic peaks of this ion, in those that one observes a better correlation with the maximum height of the peak located to 486.7 nm. (Author)

  14. 2,6-Diiminopiperidin-1-ol: an overlooked motif relevant to uranyl and transition metal binding on poly(amidoxime) adsorbents

    Energy Technology Data Exchange (ETDEWEB)

    Kennedy, Zachary C.; Cardenas, Allan J.; Corbey, Jordan F.; Warner, Marvin G.

    2016-06-06

    Glutardiamidoxime, a structural motif on sorbents used in uranium extraction from seawater, was discovered to cyclize in situ at room temperature to 2,6-diimino-piperidin-1-ol in the presence of uranyl nitrate. The new diimino motif was also generated when exposed to competing transition metals Cu(II) and Ni(II). Multinuclear μ-O bridged U(VI), Cu(II), and Ni(II) complexes featuring bound diimino ligands were isolated. A Cu(II) complex with the historically relevant cyclic imide dioxime motif is also reported for structural comparison to the reported diimino complexes.

  15. Annual report of STACY operation in F.Y. 1997. 280mm thickness slab core {center_dot} 10% enriched uranyl nitrate solution

    Energy Technology Data Exchange (ETDEWEB)

    Onodera, Seiji; Sono, Hiroki; Hirose, Hideyuki [Japan Atomic Energy Research Inst., Tokai, Ibaraki (Japan). Tokai Research Establishment] [and others

    1998-06-01

    Fifty-three times critical experiments (run number R0104 to R0156) with STACY in NUCEF, were performed in F.Y. 1997. During these experiments, 10% enriched uranyl nitrate solution was used as fuel, and core configuration was 280mm thickness and 1.5m height slab core tank with various rectangular solid reflectors; ordinary or borated concrete, polyethylene and so on, to measure mainly reactivity worth by changes of reflecting material and its thickness. Operation data of STACY in F.Y. 1997 are summarized in this report. (author)

  16. Ab initio study of the mechanism for photoinduced Yl-oxygen exchange in uranyl(VI) in acidic aqueous solution.

    Science.gov (United States)

    Réal, Florent; Vallet, Valérie; Wahlgren, Ulf; Grenthe, Ingmar

    2008-09-03

    The mechanism for the photochemically induced isotope-exchange reaction U(17/18)O2(2+)(aq) + H2(16)O U(16)O2(2+)(aq) + H2(17/18)O has been studied using quantum-chemical methods. There is a dense manifold of states between 22,000 and 54,000 cm(-1) that results from excitations from the sigma(u) and pi(u) bonding orbitals in the (1)Sigma(g)(+) ground state to the nonbonding f(delta) and f(phi) orbitals localized on uranium. On the basis of investigations of the reaction profile in the (1)Sigma(g)(+) ground state and the excited states (3)Delta(g) (the lowest triplet state) and (3)Gamma(g) (one of the several higher triplet states), the latter two of which have the electron configurations sigma(u)f(delta) and pi(u)f(phi), respectively, we suggest that the isotope exchange takes place in one of the higher triplet states, of which the (3)Gamma(g) state was used as a representative. The geometries of the luminescent (3)Delta(g) state, the lowest in the sigma(u)f(delta,phi) manifold (the "sigma" states), and the (1)Sigma(g)(+) ground state are very similar, except that the bond distances are slightly longer in the former. This is presumably a result of transfer of a bonding electron to a nonbonding f orbital, which makes the excited state in some respects similar to uranyl(V). As is the case for all of the states of the pi(u)f(delta,phi) manifold (the "pi" states), the geometry of the (3)Gamma(g) state is very different from that of the (3)Delta(g) "sigma" state and has nonequivalent U-O(yl) distances of 1.982 and 1.763 A; in the (3)Gamma(g) state, the yl-exchange takes place by transfer of a proton or hydrogen from water to the more distant yl-oxygen. The activation barriers for proton/hydrogen transfer in the ground state and the (3)Delta(g) and (3)Gamma(g) states are 186, 219, and 84 kJ/mol, respectively. The relaxation energy for the (3)Gamma(g) state in the solvent after photoexcitation is -86 kJ/mol, indicating that the energy barrier can be overcome; the "pi

  17. Natural and Man-made Antibody Repertories for Antibody Discovery

    Directory of Open Access Journals (Sweden)

    Juan C eAlmagro

    2012-11-01

    Full Text Available Antibodies are the fastest-growing segment of the biologics market. The success of antibody-based drugs resides in their exquisite specificity, high potency, stability, solubility, safety and relatively inexpensive manufacturing process in comparison with other biologics. We outline here the structural studies and fundamental principles that define how antibodies interact with diverse targets. We also describe the antibody repertoires and affinity maturation mechanisms of human, mice and chickens, plus the use of novel single-domain antibodies in camelids and sharks. These species all utilize diverse evolutionary solutions to generate specific and high affinity antibodies and illustrate the plasticity of natural antibody repertoires. In addition, we discuss the multiple variations of man-made antibody repertoires designed and validated in the last two decades, which have served as tools to explore how the size, diversity and composition of a repertoire impact the antibody discovery process.

  18. Europium, uranyl, and thorium-phenanthroline amide complexes in acetonitrile solution: an ESI-MS and DFT combined investigation.

    Science.gov (United States)

    Xiao, Cheng-Liang; Wang, Cong-Zhi; Mei, Lei; Zhang, Xin-Rui; Wall, Nathalie; Zhao, Yu-Liang; Chai, Zhi-Fang; Shi, Wei-Qun

    2015-08-28

    The tetradentate N,N'-diethyl-N,N'-ditolyl-2,9-diamide-1,10-phenanthroline (Et-Tol-DAPhen) ligand with hard-soft donor atoms has been demonstrated to be promising for the group separation of actinides from highly acidic nuclear wastes. To identify the formed complexes of this ligand with actinides and lanthanides, electrospray ionization mass spectrometry (ESI-MS) combined with density functional theory (DFT) calculations was used to probe the possible complexation processes. The 1 : 2 Eu-L species ([EuL2(NO3)](2+)) can be observed in ESI-MS at low metal-to-ligand ([M]/[L]) ratios, whereas the 1 : 1 Eu-L species ([EuL(NO3)2](+)) can be observed when the [M]/[L] ratio is higher than 1.0. However, ([UO2L(NO3)](+)) is the only detected species for the uranyl complexes. The [ThL2(NO3)2](2+) species can be observed at low [M]/[L] ratios; the 1 : 2 species ([ThL2(NO3)](3+)) and a new 1 : 1 species ([ThL(NO3)3](+)) can be detected at high [M]/[L] ratios. Collision-induced dissociation (CID) results showed that Et-Tol-DAPhen ligands can coordinate strongly with metal ions, and the coordination moieties remain intact under CID conditions. Natural bond orbital (NBO), molecular electrostatic potential (MEP), electron localization function (ELF), atoms in molecules (AIM) and molecular orbital (MO) analyses indicated that the metal-ligand bonds of the actinide complexes exhibited more covalent character than those of the lanthanide complexes. In addition, according to thermodynamic analysis, the stable cationic M-L complexes in acetonitrile are found to be in good agreement with the ESI-MS results.

  19. Study of magnetite as adsorbent material of uranyl ions; Estudo da magnetita como material adsorvedor de ions de uranilo

    Energy Technology Data Exchange (ETDEWEB)

    Leal, Roberto

    2006-07-01

    Magnetite, also known as iron ferrite, is a mineral iron and a natural magnet found in iron deposits. In addition to its magnetic intrinsic behavior, the magnetite has the capacity to remove the metallic ions from aqueous medium by adsorption phenomena. The strong magnetic character of magnetite distinguishes it from other adsorbent types, which it allows to be readily removed from solution by magnetic separation. In this work, uranium (VI) adsorption, as UO{sub 2}{sup 2+} ions, from nitric solution by synthetic magnetite was investigated. It was prepared by simultaneous precipitation process, adding a NaOH solution into a solution containing Fe{sup 2+} and Fe{sup 3+} ions. The synthetic magnetite, a black powder, has exhibited a strong magnetic response in presence of a magnetic field, without nevertheless becomes magnetic. This typical superparamagnetic behavior was confirmed by magnetization measurements. Adsorption parameters of UO{sub 2}{sup 2+} ions such as pH, the adsorbent dose, contact time and equilibrium isotherm were evaluated. Maximum uranium adsorption was observed in the pH 4.0-5.0 range. It was noticed that increase in magnetite dose increased the percent removal of uranium, but decreased the adsorption capacity of the magnetite. It was observed from the relation between adsorption and contact time that the removal has increased very fast with time, and achieved the equilibrium within 30 minutes. The results of equilibrium isotherm agreed well with the Langmuir model, and so the theoretical saturation capacity of the magnetite was determined for uranyl ions. The interaction between UO{sub 2}{sup 2+} ions and the magnetite was defined as a spontaneous chemical adsorption. (author)

  20. Grain-Size Based Additivity Models for Scaling Multi-rate Uranyl Surface Complexation in Subsurface Sediments

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Xiaoying; Liu, Chongxuan; Hu, Bill X.; Hu, Qinhong

    2016-07-01

    This study statistically analyzed a grain-size based additivity model that has been proposed to scale reaction rates and parameters from laboratory to field. The additivity model assumed that reaction properties in a sediment including surface area, reactive site concentration, reaction rate, and extent can be predicted from field-scale grain size distribution by linearly adding reaction properties for individual grain size fractions. This study focused on the statistical analysis of the additivity model with respect to reaction rate constants using multi-rate uranyl (U(VI)) surface complexation reactions in a contaminated sediment as an example. Experimental data of rate-limited U(VI) desorption in a stirred flow-cell reactor were used to estimate the statistical properties of multi-rate parameters for individual grain size fractions. The statistical properties of the rate constants for the individual grain size fractions were then used to analyze the statistical properties of the additivity model to predict rate-limited U(VI) desorption in the composite sediment, and to evaluate the relative importance of individual grain size fractions to the overall U(VI) desorption. The result indicated that the additivity model provided a good prediction of the U(VI) desorption in the composite sediment. However, the rate constants were not directly scalable using the additivity model, and U(VI) desorption in individual grain size fractions have to be simulated in order to apply the additivity model. An approximate additivity model for directly scaling rate constants was subsequently proposed and evaluated. The result found that the approximate model provided a good prediction of the experimental results within statistical uncertainty. This study also found that a gravel size fraction (2-8mm), which is often ignored in modeling U(VI) sorption and desorption, is statistically significant to the U(VI) desorption in the sediment.

  1. CsUV{sub 3}O{sub 11}, a new uranyl vanadate with a layered structure

    Energy Technology Data Exchange (ETDEWEB)

    Duribreux, I.; Dion, C.; Abraham, F. [Univ. des Sciences et Technologies de Lille, Villeneuve d`Ascq (France). Lab. de Cristallochimie et Physicochimie du Solide; Saadi, M. [Univ. Chouaib Doukkali, El Jadida (Morocco). Lab. de Chimie de Coordination et Analytique

    1999-08-01

    A new cesium uranyl vanadate CsUV{sub 3}O{sub 11} has been synthesized by solid state reaction. Its crystal structure has been determined from single-crystal X-ray diffraction data. It crystallizes in the monoclinic system with space group P2{sub 1}/a and unit cell parameters a = 11.904(2) {angstrom}, b = 6.8321(6) {angstrom}, c = 12.095(2) {angstrom}, {beta} = 106.989(5){degree}, Z = 4, and D{sub exp} = 4.89(2) g/cm{sup 3}. A full-matrix least squares refinement yielded R = 0.046 and R{sub w} = 0.045 for 1831 independent reflections with I > 3{sigma}(I) collected on a Nonius CAD4 diffractometer (MoK{alpha} radiation). The structure of CsUV{sub 3}O{sub 11} is characterized by [UV{sub 3}O{sub 11}]{sub {infinity}} layers parallel to the (001) plane. The layers, very similar to those found in UV{sub 3}O{sub 10}, are built up from VO{sub 5} square pyramids sharing corners of their equatorial bases and UO{sub 8} hexagonal bipyramids, the U atoms occupying the hexagonal holes created by the VO{sub 5} array. The Cs{sup +} ions are located between two successive layers and hold them together; the Cs{sup +} ions and two layers constitute a neutral sandwich {l_brace}(UV{sub 3}O{sub 11}{sup {minus}})-(Cs){sub 2}{sup 2+}-(UV{sub 3}O{sub 11}{sup {minus}}){r_brace}. In this unusual structure, the neutral sandwiches are stacked one above another along the [104] direction with no formal chemical bonds between the neutral sandwiches. The Cs mobilities in CsUV{sub 3}O{sub 11} and Cs carnotite are compared.

  2. N-acetylcysteine protects rats with chronic renal failure from gadolinium-chelate nephrotoxicity.

    Directory of Open Access Journals (Sweden)

    Leonardo Victor Barbosa Pereira

    Full Text Available The aim of this study was to evaluate the effect of Gd-chelate on renal function, iron parameters and oxidative stress in rats with CRF and a possible protective effect of the antioxidant N-Acetylcysteine (NAC. Male Wistar rats were submitted to 5/6 nephrectomy (Nx to induced CRF. An ionic-cyclic Gd (Gadoterate Meglumine was administrated (1.5 mM/KgBW, intravenously 21 days after Nx. Clearance studies were performed in 4 groups of anesthetized animals 48 hours following Gd- chelate administration: 1--Nx (n = 7; 2--Nx+NAC (n = 6; 3--Nx+Gd (n = 7; 4--Nx+NAC+Gd (4.8 g/L in drinking water, initiated 2 days before Gd-chelate administration and maintained during 4 days (n = 6. This group was compared with a control. We measured glomerular filtration rate, GFR (inulin clearance, ml/min/kg BW, proteinuria (mg/24 hs, serum iron (µg/dL; serum ferritin (ng/mL; transferrin saturation (%, TIBC (µg/dL and TBARS (nmles/ml. Normal rats treated with the same dose of Gd-chelate presented similar GFR and proteinuria when compared with normal controls, indicating that at this dose Gd-chelate is not nephrotoxic to normal rats. Gd-chelate administration to Nx-rats results in a decrease of GFR and increased proteinuria associated with a decrease in TIBC, elevation of ferritin serum levels, transferrin oversaturation and plasmatic TBARS compared with Nx-rats. The prophylactic treatment with NAC reversed the decrease in GFR and the increase in proteinuria and all alterations in iron parameters and TBARS induced by Gd-chelate. NAC administration to Nx rat did not modify the inulin clearance and iron kinetics, indicating that the ameliorating effect of NAC was specific to Gd-chelate. These results suggest that NAC can prevent Gd-chelate nephrotoxicity in patients with chronic renal failure.

  3. Which psychosocial factors are related to chelation adherence in thalassemia? A systematic review.

    Science.gov (United States)

    Evangeli, Michael; Mughal, Kulsoom; Porter, John B

    2010-06-01

    Good adherence to iron chelation therapy in thalassemia is crucial. Although there is evidence that adherence is related to regimen factors, there has been less emphasis on the relationship between psychosocial (psychological, demographic and social) factors and adherence. We present a systematic review of psychosocial correlates of chelation adherence in thalassemia. Nine studies met the inclusion criteria. Information was extracted regarding the study characteristics and the relationship between psychosocial factors and chelation adherence. Methodological quality was rated. The studies took place in a range of countries, were mostly cross sectional in design, and examined adherence to deferoxamine (DFO) only. Sample sizes ranged from 15 to 1573. A variety of psychosocial variables were examined. Definitions of adherence varied between studies and non adherence rates were also variable (9 to 66%). Older age was consistently associated with lower levels of chelation adherence. There were few other consistent findings. The methodological quality of studies was variable. There is a need for more methodologically sophisticated and theoretically informed studies on psychosocial correlates of chelation adherence. We offer specific suggestions.

  4. Arsenic induced oxidative stress and the role of antioxidant supplementation during chelation: a review.

    Science.gov (United States)

    Flora, S J S; Bhadauria, Smrati; Kannan, G M; Singh, Nutan

    2007-04-01

    Arsenic is a naturally occurring metalloid, ubiquitously present in the environment in both organic and inorganic forms. Arsenic contamination of groundwater in the West Bengal basin in India is unfolding as one of the worst natural geoenvironmental disaster to date. Chronic exposure of humans to high concentration of arsenic in drinking water is associated with skin lesions, peripheral vascular disease, hypertension, Blackfoot disease and high risk of cancer The underlying mechanism of toxicity includes the interaction with the sulphydryl groups and the generation of reactive oxygen species leading to oxidative stress. Chelation therapy with chelating agents like British Anti Lewisite (BAL), sodium 2,3-dimercaptopropane 1-sulfonate (DMPS), meso 2,3 dimercaptosuccinic acid (DMSA) etc., is considered to be the best known treatment against arsenic poisoning. The treatment with these chelating agents however is compromised with certain serious drawbacks/side effects. The studies show that supplementation of antioxidants along with a chelating agent prove to be a better treatment regimen. This review attempts to provide the readers with a comprehensive account of recent developments in the research on arsenic poisoning particularly the role of oxidative stress/free radicals in the toxic manifestation, an update about the recent strategies for the treatment with chelating agents and a possible beneficial role of antioxidants supplementation to achieve the optimum effects.

  5. Synthesis, characterization and in vitro anticancer evaluations of two novel derivatives of deferasirox iron chelator.

    Science.gov (United States)

    Salehi, Samie; Saljooghi, Amir Sh; Shiri, Ali

    2016-06-15

    Iron (Fe) chelation therapy was initially designed to alleviate the toxic effects of excess Fe evident in Fe-overload diseases. However, the novel toxicological properties of some Fe chelator-metal complexes have shifted significant attention to their application in cancer chemotherapy. The present study investigates the new role of deferasirox as an anticancer agent due to its ability to chelate with iron. Because of aminoacids antioxidant effect, deferasirox and its two novel amino acid derivatives have been synthesized through the treatment of deferasirox with DCC as well as glycine or phenylalanine methyl ester. All new compounds have been characterized by elemental analysis, FT-IR NMR and mass spectrometry. Therefore, the cytotoxicity of these compounds was screened for antitumor activity against some cell lines using cisplatin as a comparative standard by MTT assay and Flow cytometry. The impact of iron in the intracellular generation of reactive oxygen species was assessed on HT29 and MDA-MB-231 cells. The potential of the synthesized iron chelators for their efficacy to protect cells against model oxidative injury induced was compared. The reactive oxygen species intracellular fluorescence intensity were measured and the result showed that the reactive oxygen species intensity after iron incubation increased while after chelators incubation the reactive oxygen species intensity were decreased significantly. Besides, the effect of the synthesized compounds on mouse fibroblast cell line (L929) was simultaneously evaluated as control. The pharmacological results showed that deferasirox and its two novel aminoacid derivatives were potent anticancer agents.

  6. Reversible adsorption of catalase onto Fe(3+) chelated poly(AAm-GMA)-IDA cryogels.

    Science.gov (United States)

    Aktaş Uygun, Deniz; Uygun, Murat; Akgöl, Sinan; Denizli, Adil

    2015-05-01

    In this presented study, poly(acrylamide-glycidyl methacrylate) [poly(AAm-GMA)] cryogels were synthesized by cryopolymerization technique at sub-zero temperature. Prepared cryogels were then functionalized with iminodiacetic acid (IDA) and chelated with Fe(3+) ions in order produce the metal chelate affinity matrix. Synthesized cryogels were characterized with FTIR, ESEM and EDX analysis, and it was found that the cryogel had sponge like structure with interconnected pores and their pore diameter was about 200 μm. Fe(3+) chelated poly(AAm-GMA)-IDA cryogels were used for the adsorption of catalase and optimum adsorption conditions were determined by varying the medium pH, initial catalase concentration, temperature and ionic strength. Maximum catalase adsorption onto Fe(3+) chelated poly(AAm-GMA)-IDA cryogel was found to be 12.99 mg/g cryogel at 25 °C, by using pH 5.0 acetate buffer. Adsorbed catalase was removed from the cryogel by using 1.0M of NaCl solution and desorption yield was found to be 96%. Additionally, reusability profile of the Fe(3+) chelated poly(AAm-GMA)-IDA cryogel was also investigated and it was found that, adsorption capacity of the cryogels didn't decrease significantly at the end of the 40 reuses. Catalase activity studies were also tested and it was demonstrated that desorbed catalase retained 70% of its initial activity.

  7. Management of transfusional iron overload – differential properties and efficacy of iron chelating agents

    Directory of Open Access Journals (Sweden)

    Kwiatkowski JL

    2011-09-01

    Full Text Available Janet L Kwiatkowski The Children's Hospital of Philadelphia, Division of Hematology and University of Pennsylvania School of Medicine, Philadelphia, PA, USA Abstract: Regular red cell transfusion therapy ameliorates disease-related morbidity and can be lifesaving in patients with various hematological disorders. Transfusion therapy, however, causes progressive iron loading, which, if untreated, results in endocrinopathies, cardiac arrhythmias and congestive heart failure, hepatic fibrosis, and premature death. Iron chelation therapy is used to prevent iron loading, remove excess accumulated iron, detoxify iron, and reverse some of the iron-related complications. Three chelators have undergone extensive testing to date: deferoxamine, deferasirox, and deferiprone (although the latter drug is not currently licensed for use in North America where it is available only through compassionate use programs and research protocols. These chelators differ in their modes of administration, pharmacokinetics, efficacy with regard to organ-specific iron removal, and adverse-effect profiles. These differential properties influence acceptability, tolerability and adherence to therapy, and, ultimately, the effectiveness of treatment. Chelation therapy, therefore, must be individualized, taking into account patient preferences, toxicities, ongoing transfusional iron intake, and the degree of cardiac and hepatic iron loading. Keywords: transfusion, iron, chelation, magnetic resonance imaging

  8. Preparation of amine group-containing chelating fiber for thorough removal of mercury ions.

    Science.gov (United States)

    Ma, Nianfang; Yang, Ying; Chen, Shuixia; Zhang, Qikun

    2009-11-15

    An aminated chelating fiber (AF) with high adsorption capacity for mercury ions was prepared by grafting copolymerization of acrylonitrile onto polypropylene fiber, followed by aminating with chelating molecule diethylenetriamine. Effects of reaction conditions such as temperature, reaction time, bath ratio and dosage of catalyst on the grafting yield were studied. Chemical structure, tensile strength and thermal stability of AF were characterized. The adsorption performances for mercury were evaluated by batch adsorption experiments and kinetic experiments. The results show that AF is effective for the removal of mercury over a wide range of pH. The chelating fiber also shows much higher adsorption capacities for mercury, the equilibrium adsorption amount could be as high as 657.9 mg/g for mercury. The high adsorption capacity of Hg(2+) on AF is resulted from the strong chelating interaction between amine groups and mercury ions. Two amine groups coordinate with one mercury ion could be speculated from the adsorption capacity and amine group content on AF. The kinetic adsorption results indicate that the adsorption rates of AF for mercury are very rapid. Furthermore, the residual concentration was less than 1 microg/L with feed concentration of mercury below 1mg/L, which can meet the criterion of drinking water, which indicates that the chelating fiber prepared in this study could be applied to low-level Hg contaminated drinking water purification.

  9. Iron Chelation Inhibits Osteoclastic Differentiation In Vitro and in Tg2576 Mouse Model of Alzheimer's Disease.

    Directory of Open Access Journals (Sweden)

    Jun-Peng Guo

    Full Text Available Patients of Alzheimer's disease (AD frequently have lower bone mineral density and higher rate of hip fracture. Tg2576, a well characterized AD animal model that ubiquitously express Swedish mutant amyloid precursor protein (APPswe, displays not only AD-relevant neuropathology, but also age-dependent bone deficits. However, the underlying mechanisms remain poorly understood. As APP is implicated as a regulator of iron export, and the metal chelation is considered as a potential therapeutic strategy for AD, we examined iron chelation's effect on the osteoporotic deficit in Tg2576 mice. Remarkably, in vivo treatment with iron chelator, clinoquinol (CQ, increased both trabecular and cortical bone-mass, selectively in Tg2576, but not wild type (WT mice. Further in vitro studies showed that low concentrations of CQ as well as deferoxamine (DFO, another iron chelator, selectively inhibited osteoclast (OC differentiation, without an obvious effect on osteoblast (OB differentiation. Intriguingly, both CQ and DFO's inhibitory effect on OC was more potent in bone marrow macrophages (BMMs from Tg2576 mice than that of wild type controls. The reduction of intracellular iron levels in BMMs by CQ was also more dramatic in APPswe-expressing BMMs. Taken together, these results demonstrate a potent inhibition on OC formation and activation in APPswe-expressing BMMs by iron chelation, and reveal a potential therapeutic value of CQ in treating AD-associated osteoporotic deficits.

  10. Chapter 5 - Development of iron chelator-nanoparticle conjugates as potential therapeutic agents for Alzheimer disease.

    Science.gov (United States)

    Liu, Gang; Men, Ping; Perry, George; Smith, Mark A

    2009-01-01

    Oxidative stress is known to play a key role in the initiation and promotion of the neurodegeneration that characterizes the pathogenesis of Alzheimer disease (AD). An accumulation of redox active transition metals, including iron and copper, is likely a major generator of reactive oxidative species and other free radicals and is thought to induce a detrimental cycle of oxidative stress, amyloid-beta aggregation, and neurodegeneration. As such, metal chelators may provide an alternative therapeutic approach to sequester redox active metals and prevent the onslaught of oxidative damage. Unfortunately, however, metal chelation approaches are currently limited in their potential, since many cannot readily pass the blood-brain barrier (BBB), due to their hydrophilicity, and many are neurotoxic at high concentrations. To circumvent such issues, here we describe the development of iron chelator-nanoparticle conjugation that allows delivery of target chelator to the brain in the absence of neurotoxicity. Such nanoparticle delivery of iron chelators will likely provide a highly advantageous mode of attack on the oxidative stress that plagues AD as well as other conditions characterized by excess metal accumulation.

  11. Iron Chelation Inhibits Osteoclastic Differentiation In Vitro and in Tg2576 Mouse Model of Alzheimer's Disease.

    Science.gov (United States)

    Guo, Jun-Peng; Pan, Jin-Xiu; Xiong, Lei; Xia, Wen-Fang; Cui, Shun; Xiong, Wen-Cheng

    2015-01-01

    Patients of Alzheimer's disease (AD) frequently have lower bone mineral density and higher rate of hip fracture. Tg2576, a well characterized AD animal model that ubiquitously express Swedish mutant amyloid precursor protein (APPswe), displays not only AD-relevant neuropathology, but also age-dependent bone deficits. However, the underlying mechanisms remain poorly understood. As APP is implicated as a regulator of iron export, and the metal chelation is considered as a potential therapeutic strategy for AD, we examined iron chelation's effect on the osteoporotic deficit in Tg2576 mice. Remarkably, in vivo treatment with iron chelator, clinoquinol (CQ), increased both trabecular and cortical bone-mass, selectively in Tg2576, but not wild type (WT) mice. Further in vitro studies showed that low concentrations of CQ as well as deferoxamine (DFO), another iron chelator, selectively inhibited osteoclast (OC) differentiation, without an obvious effect on osteoblast (OB) differentiation. Intriguingly, both CQ and DFO's inhibitory effect on OC was more potent in bone marrow macrophages (BMMs) from Tg2576 mice than that of wild type controls. The reduction of intracellular iron levels in BMMs by CQ was also more dramatic in APPswe-expressing BMMs. Taken together, these results demonstrate a potent inhibition on OC formation and activation in APPswe-expressing BMMs by iron chelation, and reveal a potential therapeutic value of CQ in treating AD-associated osteoporotic deficits.

  12. Intracellular reduction/activation of a disulfide switch in thiosemicarbazone iron chelators

    Science.gov (United States)

    Akam, Eman A.; Chang, Tsuhen M.; Astashkin, Andrei V.

    2014-01-01

    Iron scavengers (chelators) offer therapeutic opportunities in anticancer drug design by targeting the increased demand for iron in cancer cells as compared to normal cells. Prochelation approaches are expected to avoid systemic iron depletion as chelators are liberated under specific intracellular conditions. In the strategy described herein, a disulfide linkage is employed as a redox-directed switch within the binding unit of an antiproliferative thiosemicarbazone prochelator, which is activated for iron coordination following reduction to the thiolate chelator. In glutathione redox buffer, this reduction event occurs at physiological concentrations and half-cell potentials. Consistent with concurrent reduction and activation, higher intracellular thiol concentrations increase cell susceptibility to prochelator toxicity in cultured cancer cells. The reduction of the disulfide switch and intracellular iron chelation are confirmed in cell-based assays using calcein as a fluorescent probe for paramagnetic ions. The resulting low-spin Fe(III) complex is identified in intact Jurkat cells by EPR spectroscopy measurements, which also document a decreased concentration of active ribonucleotide reductase following exposure to the prochelator. Cell viability and fluorescence-based assays show that the iron complex presents low cytotoxicity and does not participate in intracellular redox chemistry, indicating that this antiproliferative chelation strategy does not rely on the generation of reactive oxygen species. PMID:25100578

  13. Increased Uptake of Chelated Copper Ions by Lolium perenne Attributed to Amplified Membrane and Endodermal Damage

    Directory of Open Access Journals (Sweden)

    Anthea Johnson

    2015-10-01

    Full Text Available The contributions of mechanisms by which chelators influence metal translocation to plant shoot tissues are analyzed using a combination of numerical modelling and physical experiments. The model distinguishes between apoplastic and symplastic pathways of water and solute movement. It also includes the barrier effects of the endodermis and plasma membrane. Simulations are used to assess transport pathways for free and chelated metals, identifying mechanisms involved in chelate-enhanced phytoextraction. Hypothesized transport mechanisms and parameters specific to amendment treatments are estimated, with simulated results compared to experimental data. Parameter values for each amendment treatment are estimated based on literature and experimental values, and used for model calibration and simulation of amendment influences on solute transport pathways and mechanisms. Modeling indicates that chelation alters the pathways for Cu transport. For free ions, Cu transport to leaf tissue can be described using purely apoplastic or transcellular pathways. For strong chelators (ethylenediaminetetraacetic acid (EDTA and diethylenetriaminepentaacetic acid (DTPA, transport by the purely apoplastic pathway is insufficient to represent measured Cu transport to leaf tissue. Consistent with experimental observations, increased membrane permeability is required for simulating translocation in EDTA and DTPA treatments. Increasing the membrane permeability is key to enhancing phytoextraction efficiency.

  14. Increased Uptake of Chelated Copper Ions by Lolium perenne Attributed to Amplified Membrane and Endodermal Damage.

    Science.gov (United States)

    Johnson, Anthea; Singhal, Naresh

    2015-10-23

    The contributions of mechanisms by which chelators influence metal translocation to plant shoot tissues are analyzed using a combination of numerical modelling and physical experiments. The model distinguishes between apoplastic and symplastic pathways of water and solute movement. It also includes the barrier effects of the endodermis and plasma membrane. Simulations are used to assess transport pathways for free and chelated metals, identifying mechanisms involved in chelate-enhanced phytoextraction. Hypothesized transport mechanisms and parameters specific to amendment treatments are estimated, with simulated results compared to experimental data. Parameter values for each amendment treatment are estimated based on literature and experimental values, and used for model calibration and simulation of amendment influences on solute transport pathways and mechanisms. Modeling indicates that chelation alters the pathways for Cu transport. For free ions, Cu transport to leaf tissue can be described using purely apoplastic or transcellular pathways. For strong chelators (ethylenediaminetetraacetic acid (EDTA) and diethylenetriaminepentaacetic acid (DTPA)), transport by the purely apoplastic pathway is insufficient to represent measured Cu transport to leaf tissue. Consistent with experimental observations, increased membrane permeability is required for simulating translocation in EDTA and DTPA treatments. Increasing the membrane permeability is key to enhancing phytoextraction efficiency.

  15. Mechanism and efficiency of cell death of type II photosensitizers: effect of zinc chelation.

    Science.gov (United States)

    Pavani, Christiane; Iamamoto, Yassuko; Baptista, Maurício S

    2012-01-01

    A series of meso-substituted tetra-cationic porphyrins, which have methyl and octyl substituents, was studied in order to understand the effect of zinc chelation and photosensitizer subcellular localization in the mechanism of cell death. Zinc chelation does not change the photophysical properties of the photosensitizers (all molecules studied are type II photosensitizers) but affects considerably the interaction of the porphyrins with membranes, reducing mitochondrial accumulation. The total amount of intracellular reactive species induced by treating cells with photosensitizer and light is similar for zinc-chelated and free-base porphyrins that have the same alkyl substituent. Zinc-chelated porphyrins, which are poorly accumulated in mitochondria, show higher efficiency of cell death with features of apoptosis (higher MTT response compared with trypan blue staining, specific acridine orange/ethidium bromide staining, loss of mitochondrial transmembrane potential, stronger cytochrome c release and larger sub-G1 cell population), whereas nonchelated porphyrins, which are considerably more concentrated in mitochondria, triggered mainly necrotic cell death. We hypothesized that zinc-chelation protects the photoinduced properties of the porphyrins in the mitochondrial environment.

  16. Synthesis, characterization and cyclic voltammetric study of copper(II) and nickel(II) polymer chelates.

    Science.gov (United States)

    Azmeera, Venkanna; Rastogi, Pankaj Kumar; Adhikary, Pubali; Ganesan, Vellaichamy; Krishnamoorthi, S

    2014-09-22

    Graft copolymers based on dextran (Dx) and 2-acrylamido-2-methyl-1-propane sulphonic acid (AMPS) were synthesized by free radical initiated solution polymerization technique using ceric ammonium nitrate as initiator. These graft copolymers were used to prepare Cu(II) and Ni(II) chelates by reactions with Cu(II) and Ni(II) metal ions respectively. Graft copolymer and metal chelates were characterized by elemental analysis, intrinsic viscosity, FT-IR, scanning electron microscopy (SEM), atomic force microscopy (AFM), thermogravimetric analysis (TGA) and powder X-ray diffraction (XRD). Elemental analysis, intrinsic viscosity and FT-IR studies revealed the incorporation of metal ions to form metal chelates. SEM studies showed the change in morphology due to metal incorporation. From AFM studies it was observed that there was increase in Root mean square (RMS) roughness values in case of metal complexes. Metal chelates were observed to be thermally more stable than graft copolymer from TGA. UV-vis spectroscopy study revealed increase in absorbance values and cyclic voltammetric (CV) studies showed more than tenfold increase in redox current due to formation of Cu(II) and Ni(II) metal chelates. The binding constants of each complex determined by using UV-visible spectroscopy revealed that Cu(II) has more binding ability than Ni(II).

  17. Public health department response to mercury poisoning: the importance of biomarkers and risks and benefits analysis for chelation therapy.

    Science.gov (United States)

    McKay, Charles A

    2013-12-01

    Chelation therapy is often used to treat mercury poisoning. Public health personnel are often asked about mercury toxicity and its treatment. This paper provides a public health department response to use of a mercury-containing cosmetic in Minnesota, a perspective on two unpublished cases of chelation treatment for postulated mercury toxicity, and comments on the use of a nonsystemic treatment for removal of mercury following the Iraqi seed coat poisoning incident. Physicians should evaluate sources of exposure, biomarkers, and risks and benefits before recommending chelation therapy for their patients. Potential risks to chelation therapy and its little understood subtle or latent effects are areas of public health concern.

  18. Study of Competitive Chelating Reaction between Lanthanum and Tribromoarsenazo in the Medium of Weak Acid by Capillary Zone Electrophoresis

    Institute of Scientific and Technical Information of China (English)

    胡涌刚; 周培疆; 邓延倬; 程介克

    2003-01-01

    Two kinds of metal chelates of rare earth elements reacted with tribrimoarsenazo formed under the condition of critic acid were observed by simultaneous technique of capillary electrophoresisphotothermal interference spectrometry. The tendency of the conversion between these chelates as functions of the mole ratio of the reagent and the metal, pH value and the elapsing time was investigated. Kinetic equation of competitive chelating reaction between the TBA-La (Ⅲ) and La (Ⅲ) -critic acid were established. It was found that the competitive chelating reaction follows secondorder kinetics, for this second-order reaction, k=5.55 L·mol-1·S-1.

  19. Chelation: a fundamental mechanism of action of AGE inhibitors, AGE breakers, and other inhibitors of diabetes complications.

    Science.gov (United States)

    Nagai, Ryoji; Murray, David B; Metz, Thomas O; Baynes, John W

    2012-03-01

    This article outlines evidence that advanced glycation end product (AGE) inhibitors and breakers act primarily as chelators, inhibiting metal-catalyzed oxidation reactions that catalyze AGE formation. We then present evidence that chelation is the most likely mechanism by which ACE inhibitors, angiotensin receptor blockers, and aldose reductase inhibitors inhibit AGE formation in diabetes. Finally, we note several recent studies demonstrating therapeutic benefits of chelators for diabetic cardiovascular and renal disease. We conclude that chronic, low-dose chelation therapy deserves serious consideration as a clinical tool for prevention and treatment of diabetes complications.

  20. Thumbnail Sketches: EDTA-Type Chelating Agents in Everyday Consumer Products: Some Medicinal and Personal Care Products.

    Science.gov (United States)

    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. Antibody affinity maturation

    DEFF Research Database (Denmark)

    Skjødt, Mette Louise

    surface expression of various antibody formats in the generated knockout strain. Functional scFv and scFab fragments were efficiently displayed on yeast whereas impaired chain assembly and heavy chain degradation was observed for display of full-length IgG molecules. To identify the optimal polypeptide...... linker for yeast surface display of scFv and scFab fragments, we compared a series of different Gly-Ser-based linkers in display and antigen binding proficiency. We show that these formats of the model antibody can accommodate linkers of different lengths and that introduction of alanine or glutamate...... fragments by in vivo homologous recombination large combinatorial antibody libraries can easily be generated. We have optimized ordered assembly of three CDR fragments into a gapped vector and observed increased transformation efficiency in a yeast strain carrying a deletion of the SGS1 helicase...

  2. Antibody informatics for drug discovery

    DEFF Research Database (Denmark)

    Shirai, Hiroki; Prades, Catherine; Vita, Randi;

    2014-01-01

    to the antibody science in every project in antibody drug discovery. Recent experimental technologies allow for the rapid generation of large-scale data on antibody sequences, affinity, potency, structures, and biological functions; this should accelerate drug discovery research. Therefore, a robust bioinformatic...... infrastructure for these large data sets has become necessary. In this article, we first identify and discuss the typical obstacles faced during the antibody drug discovery process. We then summarize the current status of three sub-fields of antibody informatics as follows: (i) recent progress in technologies...... for antibody rational design using computational approaches to affinity and stability improvement, as well as ab-initio and homology-based antibody modeling; (ii) resources for antibody sequences, structures, and immune epitopes and open drug discovery resources for development of antibody drugs; and (iii...

  3. The hexadentate hydroxypyridinonate TREN-(Me-3,2-HOPO) is a more orally active iron chelator than its bidentate analogue.

    Science.gov (United States)

    Yokel, R A; Fredenburg, A M; Durbin, P W; Xu, J; Rayens, M K; Raymond, K N

    2000-04-01

    Bidentate hydroxypyridinone chelators effectively complex and facilitate excretion of trivalent iron. To test the hypothesis that hexadentate chelators are more effective than bidentate chelators at low concentrations, urinary and biliary Fe excretions were determined in Fe-loaded rats before and after administration of a bidentate chelator, Pr-(Me-3,2-HOPO), or its hexadentate analogue, TREN-(Me-3,2-HOPO). The bidentate chelator slightly increased biliary Fe excretion in Fe-loaded rats after IV (90 micromol/kg) and PO (90 or 270 micromol/kg) administration, but chelation efficiency did not exceed 1%. The hexadentate chelator markedly increased biliary Fe excretion, achieving overall chelation efficiencies of 14% after IV administration of 30 micromol/kg and 8 or 3% after PO (30 or 90 micromol/kg) administration. The hexadentate chelator was significantly more effective than the bidentate chelator after IV injection and oral dosing. In chelator-treated Fe-loaded or saline-injected rats, >90% of the excreted Fe was in the bile. Oral TREN-(Me-3,2-HOPO), given to non-Fe-loaded rats, did not appreciably change Fe output, indicating that there was little Fe depletion in the absence of Fe overload. These results support the hypothesis that greater Fe chelation efficiency can be achieved with hexadentate than with bidentate chelators at lower, and presumably safer, concentrations. The results also demonstrate that TREN-(Me-3, 2-HOPO) is a promising, orally effective, Fe chelator.

  4. Antithyroglobulin Antibodies and Antimicrosomal Antibodies in Various Thyroid Diseases

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Gwon Jun; Hong, Key Sak; Choi, Kang Won; Lee, Kyu; Koh, Chang Soon; Lee, Mun Ho; Park, Sung Hoe; Chi, Je Geun; Lee, Sang Kook [Seoul National University College of Medicine, Seoul (Korea, Republic of)

    1979-03-15

    The authors investigated the incidence of antithyroglobulin antibodies and antibodies and antimicrosomal antibodies measured by tanned red cell hemagglutination method in subjects suffering from various thyroid disorders. 1) In 15 normal patients, neither suffering from any thyroid diseases nor from any other autoimmune disorders, the antithyroglobulin antibodies were all negative, but the antimicrosomal antibody was positive only in one patient (6.7%). 2) The antithyroglobulin antibodies were positive in 31.5% (34 patients) of 108 patients with various thyroid diseases, and the antimicrosomal antibodies were positive in 37.0% (40 patients). 3) of the 25 patients with Graves' diseases, 7 patients (28.0%) showed positive for the antithyroglobulin antibodies, and 9 (36.0%) for the antimicrosomal antibodies. There was no definite differences in clinical and thyroid functions between the groups with positive and negative results. 4) Both antibodies were positive in 16 (88.9%) and 17 (94.4%) patients respectively among 18 patients with Hashimoto's thyroiditis, all of them were diagnosed histologically. 5) Three out of 33 patients with thyroid adenoma showed positive antibodies, and 3 of 16 patients with thyroid carcinoma revealed positive antibodies. 6) TRCH antibodies demonstrated negative results in 2 patients with subacute thyroiditis, but positive in one patient with idiopathic primary myxedema. 7) The number of patients with high titers(>l:802) was 16 for antithyroglobulin antibody, and 62.5% (10 patients) of which was Hashimoto's thyroiditis. Thirteen (65.0) of 20 patients with high titers (>l:802) for antimicrosomal antibody was Hashimoto's thyroiditis. TRCH test is a simple, sensitive method, and has high reliability and reproducibility. The incidences and titers of antithyroglobulin antibody and antimicrosomal antibody are especially high in Hashimoto's thyroiditis.

  5. Prediction of Antibody Epitopes

    DEFF Research Database (Denmark)

    Nielsen, Morten; Marcatili, Paolo

    2015-01-01

    Antibodies recognize their cognate antigens in a precise and effective way. In order to do so, they target regions of the antigenic molecules that have specific features such as large exposed areas, presence of charged or polar atoms, specific secondary structure elements, and lack of similarity...... to self-proteins. Given the sequence or the structure of a protein of interest, several methods exploit such features to predict the residues that are more likely to be recognized by an immunoglobulin.Here, we present two methods (BepiPred and DiscoTope) to predict linear and discontinuous antibody...

  6. Use of radiolabeled monoclonal antibodies for diagnostic imaging

    Energy Technology Data Exchange (ETDEWEB)

    Endo, Keigo (Kyoto Univ. (Japan). Faculty of Medicine)

    1990-08-01

    Monoclonal antibodies (MoAbs) are expected to carry radionuclides selectively to target tissues and to offer antigen-specific diagnosis. Indium (In)-111 has many favorable nuclear properties and is efficiently labeled with MoAbs using DAPA as a bifunctional chelating agent. In-111 labeled MoAbs are clinically employed for the diagnosis of malignant melanoma, colorectal cancer and acute myocardial infarction in Japan. Although non-specific deposit of In-111 was seen in liver and bone-marrow, scintigraphy using In-111 labeled MoAbs was encouraging, since it detected about 80% of tumors, tumors missed by conventional diagnostic methods such as CT, and tumors in patients with normal serum CEA values, and acute myocarditis as well as acute myocardial infarction was positive with In-111 labeled Fab fraction of anti-myosin Ab. Acute or subacute toxicity was not observed. Human anti-murine antibody (HAMA) was detected in 53 of 64 (82.8%) patients who were intravenously administered with 20 to 42 mg of anti-melanoma or anti-CEA MoAbs (whole IgG). In contrast, only 5 of 406 (1.2%) patients had detectable levels of HAMA in their serum after receiving 0.5 mg of Fab fraction of MoAb. Recently mouse-human chimeric Ab has been produced by recombinant DNA techniques, which localized well in xenografted tumors and seems to be promising for clinical use. Investigations are under way to increase the tumor to non-tumor ratio by modifying chelating agents for coupling MoAbs with radionuclides. (author).

  7. Synthesis and Preparation of Polysulfone Hollow Fiber Chelating Membrane Modified with Thiourea

    Institute of Scientific and Technical Information of China (English)

    WANG Bing; HUANG Lei; XIAO Feng

    2006-01-01

    Several kinds of chloromethyl polysulfones (CMPF) with different chlorinity and reactive groups were synthesized by Friedel-crafts reaction, which could be utilized as reactively matrix membrane materials. The CMPF hollow matrix membranes were prepared with phase inversion by utilization of CMPF/additive/DMAC casting solution and CMPF as membrane materials. It was found that the effects of additive content, bore liquid and dry spinning distance on the structure of CMPF hollow fiber matrix membrane were different. A high qualified polysulfone hollow fiber chelating membrane modified with thiourea as chelating groups was prepared using CMPF as membrane matrix materials,through the reaction between thiourea and CMPF hollow fiber matrix membrane to afford the methyl iso-thiourium polysulfone. The experimental results showed that thermal drawing could increase the mechanical properties of matrix membrane, and the thermal treatment could increase the homogeneity and stability of the structure of polysulfone hollow fiber chelating membrane modified with thiourea.

  8. Inhibitor Ranking Through QM based Chelation Calculations for Virtual Screening of HIV-1 RNase H inhibition

    DEFF Research Database (Denmark)

    Poongavanam, Vasanthanathan; Svendsen, Casper Steinmann; Kongsted, Jacob

    2014-01-01

    . Furthermore, full protein fragment molecular orbital (FMO) calculations were conducted and subsequently analysed for individual residue stabilization/destabilization energy contributions to the overall binding affinity in order to better understand the true and false predictions. After a successful assessment......Quantum mechanical (QM) calculations have been used to predict the binding affinity of a set of ligands towards HIV-1 RT associated RNase H (RNH). The QM based chelation calculations show improved binding affinity prediction for the inhibitors compared to using an empirical scoring function...... of the methods based on the use of a training set of molecules, QM based chelation calculations were used as filter in virtual screening of compounds in the ZINC database. By this, we find, compared to regular docking, QM based chelation calculations to significantly reduce the large number of false positives...

  9. Separation of metal chelates and organometallic compounds by SFC and SFE/GC.

    Science.gov (United States)

    Wai, C M; Wang, S

    2000-07-05

    Supercritical fluid chromatography (SFC) combines the high diffusion coefficients of gas chromatography (GC) and the solubility properties of liquid chromatography (LC). SFC generally requires lower temperatures for chromatographic separations and thus is more suitable for analyzing thermally labile compounds including a number of metal chelates and organometallic compounds. SFC also allows interfacing between supercritical fluid extraction (SFE) and chromatographic analysis of metal-containing compounds. A large number of metal chelates and organometallic compounds can be separated by SFC. This article summarizes SFC separation of various chelates of transition metals, heavy metals, lanthanides and actinides as well as organometallic compounds of lead, mercury, and tin reported in the recent literature. This article also discusses SFC detection systems and the determination of solubility of organometallic compounds by SFC.

  10. Synthesis and Characterization of 2-Decyl-DTPA and Its Gd(Ⅲ) Chelate

    Institute of Scientific and Technical Information of China (English)

    FENG Zhi-ming; LI Feng; CHEN Rong; ZHU Xiao-juan; LI Xiao-ru

    2004-01-01

    The present paper covers the synthesis and the characterization of ligand 2-decyl-3, 6, 9-tris(carboxymethyl)-3,6,9-triazaundecan-1,11-dioic acid, H5L, and its Gd(Ⅲ) chelate. The protonation constants for H5L(lgKHi=10.90, 8.50, 4.55, 2.92, 2.20) and the stability constant for GdL2- (lgKGdL2-=22.80) were determined by means of potentiometric titration. They are similar to the corresponding values of DTPA and Gd-DTPA, respectively. The results obtained show that the basicity of the ligand and the stability constant of its Gd(Ⅲ) chelate are not obviously altered after the introduction of a linear chain decyl group into the terminal acetic acid residue of DTPA. The Gd(Ⅲ) chelate may be a potential contrast agent with liver-specificity for magnetic resonance imaging(MRI).

  11. Critical evaluation of treatment strategies involving adsorption and chelation for wastewater containing copper, zinc and cyanide

    Energy Technology Data Exchange (ETDEWEB)

    Bose, P.; Bose, M.A.; Kumar, S. [Indian Inst. of Technology, Kanpur (India). Dept Civil Engineering, Environmental Engineering & Management Programme

    2002-11-01

    Industrial wastewater containing heavy metals and cyanide must be treatment for removal of both metals and cyanide before disposal. The study described evaluated treatment strategies involving some indigenous adsorbents and a low-cost chelating agent for treatment of a simulated wastewater containing copper and zinc, complexed with cyanide. Treatment strategies involving three adsorbents, sulfonated coal, biosorbent G. lucidum, and iron oxide coated sand (IOCS), and a chelating agent, insoluble agro-based starch xanthate (IAX), were tested. The evaluation procedure involved comparison of the performance of these treatment strategies with that of conventional treatment. Results indicate that treatment using the chelating agent IAX has the greatest potential as an alternative to the conventional treatment technique. The three adsorbents tested, although reported to be very effective in removing copper and zinc from pure systems, exhibit diminished metal removal capacity in the presence of cyanide, and hence are unsuitable.

  12. The effect of metal chelators on the production of hydroxyl radicals in thylakoids.

    Science.gov (United States)

    Snyrychová, Iva; Pospísil, Pavel; Naus, Jan

    2006-06-01

    The effect of metal chelators (EDTA, DTPA and Desferal) on the metal-catalyzed decomposition of hydrogen peroxide was studied using EPR spin-trapping spectroscopy. The formation of hydroxyl radicals (OH*) in both chemical (Fenton reaction) and biological (thylakoids) systems was stimulated by EDTA. DTPA promoted the generation of OH* in the presence of strong reducing agents, whereas in their absence it acted as an antioxidant. Desferal suppressed OH* production even in the presence of reductants. In our study, we have shown that metal chelators can both stimulate and suppress the formation of OH*, depending on the experimental conditions. In illuminated thylakoids we have observed prooxidant effect of EDTA and DTPA, possibly due to their reduction by some component of the electron transport chain. According to our results, metal chelators should not be used as antioxidants without prior testing of their effect in given samples.

  13. Bis-NHC chelate complexes of nickel(0) and platinum(0).

    Science.gov (United States)

    Brendel, Matthias; Braun, Carolin; Rominger, Frank; Hofmann, Peter

    2014-08-11

    For a long time d(10)-ML2 fragments have been known for their potential to activate unreactive bonds by oxidative addition. In the development of more active species, two approaches have proven successful: the use of strong σ-donating ligands leading to electron-rich metal centers and the employment of chelating ligands resulting in a bent coordination geometry. Combining these two strategies, we synthesized bis-NHC chelate complexes of nickel(0) and platinum(0). Bis(1,5-cyclooctadiene)nickel(0) and -platinum(0) react with bisimidazolium salts, deprotonated in situ at room temperature, to yield tetrahedral or trigonal-planar bis-NHC chelate olefin complexes. The synthesis and characterization of these complexes as well as a first example of C-C bond activation with these systems are reported. Due to the enforced cis arrangement of two NHCs, these compounds should open interesting perspectives for bond-activation chemistry and catalysis.

  14. REVIEW ARTICLE:Future of Lead Chelation – Distribution and Treatment

    Directory of Open Access Journals (Sweden)

    Venkatesh Thuppil

    2012-01-01

    Full Text Available Lead is the major environmental toxin resulting in the ill health and deleterious effect on almost all organs in the human body in a slow and effective manner. The best treatment for lead poisoning is chelation therapy which is next only to prevention. The authors describe the disruption of homeostasis of the human body by lead in various tissues like blood, bones, liver, kidneys and brain; and the ability of lead to enter the cell using calcium channels and calcium receptors like Ca++ dependant K+ ion channels, transient receptor potential channels, T-tubules, calmodulin receptors, inositol trisphosphate receptors and ryanodine receptors. We report a few novel chelating agents like ionophores, decadentate ligands, picolinate ligands, octadentate ligand, allicin, thiamine, that show good potential for being used in chelation therapy. Future of leadpoisoning is a challenge to all and it needs to be meticulously studies to have an economic and health approach.

  15. Radiopharmaceutical stannic Sn-117m chelate compositions and methods of use

    Energy Technology Data Exchange (ETDEWEB)

    Srivastava, Suresh C. (Setauket, NY); Meinken, George E. (Middle Island, NY)

    2001-01-01

    Radiopharmaceutical compositions including .sup.117m Sn labeled stannic (Sn.sup.4+) chelates are provided. The chelates are preferably polyhydroxycarboxylate, such as oxalates, tartrates, citrates, malonates, gluconates, glucoheptonates and the like. Methods of making .sup.117m Sn-labeled (Sn.sup.4+) polyhydroxycarboxylic chelates are also provided. The foregoing pharmaceutical compositions can be used in methods of preparing bone for scintigraphical analysis, for radiopharmaceutical skeletal imaging, treatment of pain resulting from metastatic bone involvement, treatment of primary bone cancer, treatment of cancer resulting from metastatic spread to bone from other primary cancers, treatment of pain resulting from rheumatoid arthritis, treatment of bone/joint disorders and to monitor radioactively the skeletal system.

  16. Conversion of agonist site to metal-ion chelator site in the beta(2)-adrenergic receptor

    DEFF Research Database (Denmark)

    Elling, C E; Thirstrup, K; Holst, Birgitte

    1999-01-01

    in the mutant receptors not by normal catecholamine ligands but instead either by free zinc ions or by zinc or copper ions in complex with small hydrophobic metal-ion chelators. Chelation of the metal ions by small hydrophobic chelators such as phenanthroline or bipyridine protected the cells from the toxic......Previously metal-ion sites have been used as structural and functional probes in seven transmembrane receptors (7TM), but as yet all the engineered sites have been inactivating. Based on presumed agonist interaction points in transmembrane III (TM-III) and -VII of the beta(2)-adrenergic receptor......, in this paper we construct an activating metal-ion site between the amine-binding Asp-113 in TM-III-or a His residue introduced at this position-and a Cys residue substituted for Asn-312 in TM-VII. No increase in constitutive activity was observed in the mutant receptors. Signal transduction was activated...

  17. Compositions, antibodies, asthma diagnosis methods, and methods for preparing antibodies

    Energy Technology Data Exchange (ETDEWEB)

    Jin, Hongjun; Zangar, Richard C.

    2017-01-17

    Methods for preparing an antibody are provided with the method including incorporating 3-bromo-4-hydroxy-benzoic acid into a protein to form an antigen, immunizing a mammalian host with the antigen, and recovering an antibody having an affinity for the antigen from the host. Antibodies having a binding affinity for a monohalotyrosine are provided as well as composition comprising an antibody bound with monohalotyrosine. Compositions comprising a protein having a 3-bromo-4-hydroxy-benzoic acid moiety are also provided. Methods for evaluating the severity of asthma are provide with the methods including analyzing sputum of a patient using an antibody having a binding affinity for monohalotyrosine, and measuring the amount of antibody bound to protein. Methods for determining eosinophil activity in bodily fluid are also provided with the methods including exposing bodily fluid to an antibody having a binding affinity for monohalotyrosine, and measuring the amount of bound antibody to determine the eosinophil activity.

  18. Chelator-induced phytoextraction of zinc and copper by rice seedlings.

    Science.gov (United States)

    Yu, Xiao-Zhang; Wang, Dun-Qiu; Zhang, Xue-Hong

    2014-05-01

    Solution culture was carried to investigate capacity of synthetic aminopolycarboxylic acids (ethylenediamine tetraacetate, N-hydroxyethylenediaminetriacetic acid, and diethylenetriamine-pentaacetate) for enhancing botanical removal and transport of heavy metals (Cu and Zn) by plants. Biodegradable organic acids (citric acid, malic acid, and oxalic acid) were also selected as alternatives to compare them with synthesized chelating agents for effectiveness. Young rice seedlings (Oryza sativa L. cv. XZX 45) were grown in nutrient solutions treated with single or combined metal solutions in presence or absence of chelating compounds. Calculation by chemical equilibrium program VISUAL MINTEQ showed that different chelating compounds had various complex potential with Cu(2+) and Zn(2+) ions, in which synthetic chelators exhibited higher complexed capability than biodegradable organic acids. All applied synthetic aminopolycarboxylic acids significantly decreased removal of metal from nutrient solution (p 0.05), compared with the treatment without metal ligands. Synthetic aminopolycarboxylic acids significantly decreased metal concentrations in plant materials in all treatments (p < 0.01). However, biodegradable organic acids decreased metal concentrations in roots (p < 0.01), but enhanced them in shoots (p < 0.01). Results obtained indicated that synthetic aminopolycarboxylic acids decreased uptake of metals by rice seedlings, but translocation of metals complexed within plant materials was evident. Although exogenous biodegradable organic acids showed negligible effect on botanical removal of metals, metals complexed with organic acids was more mobile than those complexed with other chelating agents. These information collected here had important implication for the use of biodegradable metal chelators in transport of essential micronutrients in plant nutrition.

  19. Ethyl acetoacetate ligand distribution in the course of titanium n-butoxide chelation

    Energy Technology Data Exchange (ETDEWEB)

    Kurajica, S., E-mail: stankok@fkit.hr; Škorić, I.; Lozić, I.; Mandić, V.

    2014-10-15

    Sols obtained by chelation of titanium n-butoxide with ethyl acetoacetate, Eaa, in various ratios have been subjected to FTIR, {sup 1}H and {sup 13}C NMR, HSQC and UV–Vis spectroscopy in order to provide insight in the compounds obtained, their structure and quantitative relationships. Three compounds, the bis-chelated monomer, Ti(O{sup n}Bu){sub 2}(Eaa){sub 2}, bis-chelated dimer, (Ti(O{sup n}Bu){sub 3}Eaa){sub 2} and monochelated dimer, Ti{sub 2}(O{sup n}Bu){sub 7}Eaa have been established. As the molar ratio Eaa/Ti(O{sup n}Bu){sub 4} increases, the coordination changes from the monochelated and bis-chelated dimer to the bis-chelated monomer. Additionally, the transesterification reaction, influencing the chemical composition of the compounds was noted. The hydrolysis of the prepared sols was partial, leaving some residual butoxy and ethyl acetoacetate groups attached to titanium. Thermal treatment of the prepared amorphous gels at 350 °C yielded with the formation of nanocrystalline anatase. It was noted that high Eaa/Tnb ratio slightly retards the anatase formation. - Highlights: • Titanium n-butoxide was modified with ethyl acetoacetate in various ratios. • Among other chelate phases, previously undescribed Ti{sub 2}(O{sup n}Bu){sub 7}Eaa was obtained. • NMR-based mass balance procedure was introduced to obtain quantitative relationships. • The transesterification reaction has been noted. • Nanocrystalline anatase has been obtained by thermal treatment at 350 °C.

  20. Stereoselective coordination: a six-membered P,N-chelate tailored for asymmetric allylic alkylation.

    Science.gov (United States)

    Császár, Z; Farkas, G; Bényei, A; Lendvay, G; Tóth, I; Bakos, J

    2015-10-01

    Six-membered chelate complexes [Pd(1a-b)Cl2], (2a-b) and [Pd(1a-b)(η(3)-PhCHCHCHPh)]BF4, (3a-b) of P,N-type ligands 1a, ((2S,4S)-2-diphenyl-phosphino-4-isopropylamino-pentane) and 1b, ((2S,4S)-2-diphenyl-phosphino-4-methylamino-pentane) have been prepared. The Pd-complexes have been characterized in solution by 1D and 2D NMR spectroscopy. The observed structures were confirmed by DFT calculations and in the case of 2a also by X-ray crystallography. Unexpectedly, the coordination of the all-carbon-backbone aminophosphine 1a resulted in not only a stereospecific locking of the donor nitrogen atom into one of the two possible configurations but also the conformation of the six-membered chelate rings containing three alkyl substituents was forced into the same single chair structure showing the axially placed isopropyl group on the coordinated N-atom. The stereodiscriminative complexation of 1a led to the formation of a palladium catalyst with a conformationally rigid chelate having a configurationally fixed nitrogen and electronically different coordination sites due to the presence of P and N donors. The stereochemically fixed catalyst provided excellent ee's (up to 96%) and activities in asymmetric allylic alkylation reactions. In contrast, the chelate rings formed by 1b exist in two different chair conformations, both containing axial methyl groups, but with the opposite configurations of the coordinated N-atom. Pd-complexes of 1b provided low enantioselectivities in similar alkylations, therefore emphasizing the importance of the stereoselective coordination of N-atoms in analogous P-N chelates. The factors determining the coordination of the ligands were also studied with respect to the chelate ring conformation and the nitrogen configuration.

  1. The preparation and characterization of novel human-like collagen metal chelates

    Energy Technology Data Exchange (ETDEWEB)

    Zhu, Chenhui; Sun, Yan [Shaanxi Key Laboratory of Degradable Biomedical Materials, School of Chemical Engineering Northwest University, Xi' an 710069 (China); Shaanxi R and D Center of Biomaterials and Fermentation Engineering, Xi' an 710069 (China); Wang, Yaoyu [Key Laboratory of Synthetic and Natural Functional Molecule Chemistry of the Ministry of Education, Xi' an 710069 (China); Luo, Yane, E-mail: luoyane@nwu.edu.cn [Shaanxi Key Laboratory of Degradable Biomedical Materials, School of Chemical Engineering Northwest University, Xi' an 710069 (China); Shaanxi R and D Center of Biomaterials and Fermentation Engineering, Xi' an 710069 (China); Fan, Daidi, E-mail: fandaidi@nwu.edu.cn [Shaanxi Key Laboratory of Degradable Biomedical Materials, School of Chemical Engineering Northwest University, Xi' an 710069 (China); Shaanxi R and D Center of Biomaterials and Fermentation Engineering, Xi' an 710069 (China)

    2013-07-01

    In order to develop the nutritional trace elements which could be absorbed and utilized effectively, protein chelates were adopted. Calcium, copper and manganese were considered based on their physiological functions, and the new chelates of HLC-Ca, HLC-Cu and HLC-Mn were formed in MOPS or MES buffer and purified by gel chromatography, and then freeze-dried. And they were detected and analyzed by atomic absorption spectrophotometry, ultraviolet–visible absorption (UV–vis) spectroscopy, Fourier transform infrared (FTIR) spectroscopy, fluorescence quenching method, circular dichroism (CD) and differential scanning calorimetry (DSC). The results showed that some chemical reactions happened between HLC and the three metal ions to form new chemical compounds. The thermodynamic parameters, ∆H, ∆G and ∆S, showed that the chelation process between HLC and metal ions was performed spontaneously. Fluorescence quenching spectra of HLC indicated that the quenching mechanism was static in nature. According to the data of DSC, the new chelates were more stable than the free HLC. And HLC-metal complex was non-toxic to the BHK21 cell through MTT assay. - Highlights: ► HLC-Ca, HLC-Cu and HLC-Mn were new chemical compounds and different to free HLC. ► Possible sites for Ca{sup 2+}, Cu{sup 2+} and Mn{sup 2+} to bind with HLC were presented. ► The chelation process between HLC and metal ions was performed spontaneously. ► The thermodynamic stability of the new chelates was higher than that of free HLC.

  2. Arsenic and lead induced free radical generation and their reversibility following chelation.

    Science.gov (United States)

    Flora, S J S; Flora, G; Saxena, G; Mishra, M

    2007-04-15

    Health hazards caused by heavy metals have become a great concern to the population. Lead and arsenic are one of the most important current global environmental toxicants. Their toxic manifestations are being considered caused primarily due to the imbalance between pro-oxidant and antioxidant homeostasis and also due to a high affinity of these metals for thiol groups on functional proteins. They also interfere with a number of other body functions and are known to affect central nervous system (CNS), hematopoietic system, liver and kidneys and produce serious disorders. They produce both acute and chronic poisoning, of which chronic poisoning is more dangerous as its very difficult to revert back to normal condition after chronic exposure to these insidious metals present in our life. Despite many years of research, we are still far from an effective treatment of chronic plumbism and arsenicosis. Current approved treatment lies in the administration of chelating agents that forms an insoluble complex with the metal and removes it. They have been used clinically as antidotes for treating acute and chronic poisoning. The most widely used chelating agents are calcium disodium ethylenediamine tetra acetic acid (CaNa2EDTA), D-penicillamine and British anti-lewisite (BAL). Meso 2,3 dimercaptosuccinic acid (DMSA), an analogue of BAL, has been tried successfully in animals as well as in humans. But it is unable to remove the metal from intracellular sites. Effective chelation therapy for intoxication by heavy metals depends on whether the chelating agents are able to reach the intracellular site where the heavy metal is firmly bound. One of the important approaches has been the use of combination therapy. This includes use of structurally different chelators or a combination of an adjuvant/ antioxidant/ herbal extracts and a chelator to provide better clinical/ biochemical recovery. A number of other strategies have been suggested to minimize the numerous problems. This

  3. Insight into Hydrogen Bonding of Uranyl Hydroxide Layers and Capsules by Use of 1H Magic-Angle Spinning NMR Spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Alam, Todd M. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States). Dept. of Organic Material Science; Liao, Zuolei [Oregon State Univ., Corvallis, OR (United States). Dept. of Chemistry and Materials; Nyman, May [Oregon State Univ., Corvallis, OR (United States). Dept. of Chemistry and Materials; Yates, Jonathan [Univ. of Oxford (United Kingdom). Dept. of Materials

    2016-04-27

    In this paper, solid-state 1H magic-angle spinning (MAS) NMR was used to investigate local proton environments in anhydrous [UO2(OH)2] (α-UOH) and hydrated uranyl hydroxide [(UO2)4O(OH)6·5H2O (metaschoepite). For the metaschoepite material, proton resonances of the μ2-OH hydroxyl and interlayer waters were resolved, with two-dimensional (2D) double-quantum (DQ) 1H–1H NMR correlation experiments revealing strong dipolar interactions between these different proton species. The experimental NMR results were combined with first-principles CASTEP GIPAW (gauge including projector-augmented wave) chemical shift calculations to develop correlations between hydrogen-bond strength and observed 1H NMR chemical shifts. Finally, these NMR correlations allowed characterization of local hydrogen-bond environments in uranyl U24 capsules and of changes in hydrogen bonding that occurred during thermal dehydration of metaschoepite.

  4. Multifunctional uranyl hybrid materials: structural diversities as a function of pH, luminescence with potential nitrobenzene sensing, and photoelectric behavior as p-type semiconductors.

    Science.gov (United States)

    Song, Jian; Gao, Xue; Wang, Zhi-Nan; Li, Cheng-Ren; Xu, Qi; Bai, Feng-Ying; Shi, Zhong-Feng; Xing, Yong-Heng

    2015-09-21

    A series of uranyl-organic frameworks (UOFs), {[(UO2)2(H2TTHA)(H2O)]·4,4'-bipy·2H2O}n (1), {[(UO2)3(TTHA)(H2O)3]}n (2), and {[(UO2)5(TTHA) (HTTHA)(H2O)3]·H3O}n (3), have been obtained by the hydrothermal reaction of uranyl acetate with a flexible hexapodal ligand (1,3,5-triazine-2,4,6-triamine hexaacetic acid, H6TTHA). These compounds exhibited three distinct 3D self-assembly architectures as a function of pH by single-crystal structural analysis, although the used ligand was the same in each reaction. Surprisingly, all of the coordination modes of the H6TTHA ligand in this work are first discovered. Furthermore, the photoluminescent results showed that these compounds displayed high-sensitivity luminescent sensing functions for nitrobenzene. Additionally, the surface photovoltage spectroscopy and electric-field-induced surface photovoltage spectroscopy showed that compounds 1-3 could behave as p-type semiconductors.

  5. Additional studies on mixed uranyl oxide-hydroxide hydrate alteration products of uraninite from the palermo and ruggles granitic pegmatites, grafton county, New Hampshire

    Science.gov (United States)

    Foord, E.E.; Korzeb, S.L.; Lichte, F.E.; Fitzpatrick, J.J.

    1997-01-01

    Additional studies on an incompletely characterized secondary uranium "mineral" from the Ruggles and Palermo granitic pegmatites, New Hampshire, referred to as mineral "A" by Frondel (1956), reveal a mixture of schoepite-group minerals and related uranyl oxide-hydroxide hydrated compounds. A composite chemical analysis yielded (in wt.%): PbO 4.85 (EMP), UO3 83.5 (EMP), BaO 0.675 (av. of EMP and ICP), CaO 0.167 (av. of EMP and ICP), K2O 2.455 (av. of EMP and ICP), SrO 0.21 (ICP), ThO2 0.85 (ICP), H2O 6.9, ??99.61. Powder-diffraction X-ray studies indicate a close resemblance in patterns between mineral "A" and several uranyl oxide-hydroxide hydrated minerals, including the schoepite family of minerals and UO2(OH)2. The powder-diffraction data for mineral "A" are most similar to those for synthetic UO2.86??1.5H2O and UO2(OH)2, but other phases are likely present as well. TGA analysis of both mineral "A" and metaschoepite show similar weight-loss and first derivative curves. The dominant losses are at 100??C, with secondary events at 400?? and 600??C. IR spectra show the presence of (OH) and H2O. Uraninite from both pegmatites, analyzed by LAM-ICP-MS, shows the presence of Th, Pb, K and Ca.

  6. Human germline antibody gene segments encode polyspecific antibodies.

    Science.gov (United States)

    Willis, Jordan R; Briney, Bryan S; DeLuca, Samuel L; Crowe, James E; Meiler, Jens

    2013-04-01

    Structural flexibility in germline gene-encoded antibodies allows promiscuous binding to diverse antigens. The binding affinity and specificity for a particular epitope typically increase as antibody genes acquire somatic mutations in antigen-stimulated B cells. In this work, we investigated whether germline gene-encoded antibodies are optimal for polyspecificity by determining the basis for recognition of diverse antigens by antibodies encoded by three VH gene segments. Panels of somatically mutated antibodies encoded by a common VH gene, but each binding to a different antigen, were computationally redesigned to predict antibodies that could engage multiple antigens at once. The Rosetta multi-state design process predicted antibody sequences for the entire heavy chain variable region, including framework, CDR1, and CDR2 mutations. The predicted sequences matched the germline gene sequences to a remarkable degree, revealing by computational design the residues that are predicted to enable polyspecificity, i.e., binding of many unrelated antigens with a common sequence. The process thereby reverses antibody maturation in silico. In contrast, when designing antibodies to bind a single antigen, a sequence similar to that of the mature antibody sequence was returned, mimicking natural antibody maturation in silico. We demonstrated that the Rosetta computational design algorithm captures important aspects of antibody/antigen recognition. While the hypervariable region CDR3 often mediates much of the specificity of mature antibodies, we identified key positions in the VH gene encoding CDR1, CDR2, and the immunoglobulin framework that are critical contributors for polyspecificity in germline antibodies. Computational design of antibodies capable of binding multiple antigens may allow the rational design of antibodies that retain polyspecificity for diverse epitope binding.

  7. Prediction of antibody persistency from antibody titres to natalizumab

    DEFF Research Database (Denmark)

    Jensen, Poul Erik H; Koch-Henriksen, Nils; Sellebjerg, Finn Thorup;

    2012-01-01

    In a subgroup of patients with multiple sclerosis natalizumab therapy causes generation of anti-natalizumab antibodies that may be transient or persistent. It is recommended to discontinue natalizumab therapy in persistently antibody-positive patients.......In a subgroup of patients with multiple sclerosis natalizumab therapy causes generation of anti-natalizumab antibodies that may be transient or persistent. It is recommended to discontinue natalizumab therapy in persistently antibody-positive patients....

  8. Chelation in Metal Intoxication XLVI:Synthesis of Some α-Mercapto-β-Substituted Aryl Acrylic Acids and Their In vitro Cadmium Chelating Ability

    Institute of Scientific and Technical Information of China (English)

    MADHUMITA CHATTERJEE; VINOD K. DWIVEDI; KIRTI KHANDEKAR; SUSHIL K. TANDON

    2004-01-01

    Objective To synthesize some new α-mercapto-β-substituted aryl acrylic acids, characterize them and investigate their in vitro cadmium chelating ability. Methods Six α-mercapto-β-substituted aryl acrylic acids were prepared by the alkaline hydrolysis of 5-(aryl methylene)rhodanines, obtained from the condensation of substituted aldehydes and rhodanine following the reported procedure. The new compounds were characterized by elemental analysis, infrared (IR) and nuclear magnetic resonance (NMR) spectroscopy. The liver and kidney from cadmium chloride pre-administered rats were homogenized and their nuclear mitochondrial fraction (NMF) and supernatant cytosol fraction (SCF) were separated. A measured volume of each fraction was dialyzed separately using "dialysis sack" against buffered-KCl medium containing a compound in the final concentration of 1×10-3 mol/L for 3 h at 37℃C. The whole content of "sack" was subjected to cadmiumestimation following digestion with conc. Nitric acid was detected using flame atomic absorption spectrometer. Results The in vitro screening showed that α-mercapto-β-(p-methoxyphenyl)acrylic acid (compound 2) and α-mercapto-β-(m-methoxy, p-hydroxyphenyl) acrylic acid (compound 4) were more effective than α-mercapto-β-thienyl acrylic acid (compound 1) and α-mercapto-β-(p-dimethylaminophenyl) acrylic acid (compound 3) in mobilizing cadmium as their dialyzable chelates. The presence of a methoxy group on the phenyl moiety (compounds 2 and 4) increases the metal chelating ability of mercapto acrylic acids. Conclusions Compounds 2 and 4 seem to have accessibility to the cellular system and capability of chelating-out the intracellularly bound cadmium.

  9. Monoclonal antibodies in myeloma

    DEFF Research Database (Denmark)

    Sondergeld, P.; van de Donk, N. W. C. J.; Richardson, P. G.;

    2015-01-01

    The development of monoclonal antibodies (mAbs) for the treatment of disease goes back to the vision of Paul Ehrlich in the late 19th century; however, the first successful treatment with a mAb was not until 1982, in a lymphoma patient. In multiple myeloma, mAbs are a very recent and exciting add...

  10. Antibody Blood Tests

    Science.gov (United States)

    ... What do I do if I have a negative blood test (or panel) but I’m still having symptoms? While it is rare, it is possible for patients to have a negative antibody test results and still have celiac disease. ...

  11. RBC Antibody Screen

    Science.gov (United States)

    ... test also may be used to help diagnose autoimmune-related hemolytic anemia in conjunction with a DAT. This condition may be caused when a person produces antibodies against his or her own RBC antigens. This can happen with some autoimmune disorders , such as lupus , with diseases such as ...

  12. STUDY ON THE KINETICS OF POLYMERIZATION OF MMA BY COPPER(Ⅱ) CHELATING RESINS

    Institute of Scientific and Technical Information of China (English)

    WangHongzuo; JiangYuanzhang; 等

    1993-01-01

    The polymerization of MMA initiated by copper(Ⅱ) chelating resins/CCl4 system was studied.From the kinetic data,the kinetic equation of polymerization can be expressed as Rp=Ke-56400/RT[MMA]1.57[CCl4]m[RESIN-Cu]0.18 where m:3-4.5,when[CCl4] 0.1-6.93M.The free radical polymerization mechanism is proposed.The primary radicals are formed by the process of complexation-chlorine transformation among the copper(Ⅱ) chelating resin,CCl4 and methacrylate.

  13. Treatment of metal-containing wastewater by adsorption of metal-chelate complexes onto activated carbon

    Energy Technology Data Exchange (ETDEWEB)

    Shay, M.A.

    1989-01-01

    To eliminate difficulties associated with interference of chelating or complexing agents on precipitation of heavy metals from wastewaters, the feasibility of a process which utilized chelating agents in the removal of the heavy metals was investigated. Heavy metal ions were removed from simulated metal plating wastewater by sorption of a heavy metal chelate complex onto activated carbon. In this process, a chelate which might be present in a wastewater could be used in removal of a heavy metal, rather than interfere with its removal. System development of a continuous flow process consisted of bench scale column tests to answer questions about key adsorption column operating parameters. The metals investigated were Cu(II), Ni(II) and Zn(II). Hydrogen ion concentration had the largest effect on removal of heavy metalchelate complexes, but contact time and heavy metal:chelate ratio were important. The normal contact time for activated carbon columns of 30 to 60 minutes was found adequate to achieve heavy metal-chelate removals of at least 90% for citrate or EDTA complexes. For citrate complexes better removals were achieved at heavy metal:chelate ratios greater than 1:1. For EDTA, there was no advantage to ratios greater than 1:1. Increasing pH, at least to pH 9.0, increased the heavy metal chelate removal; however, for EDTA, removals greater than 90% could be achieved at a pH as low as 3.0. The maximum amount of Cu(II)-citrate complex that could be removed was 2.8 mg per gram of carbon, the maximum amount for Zn(II)citrate complex was 1.2 mg per gram of carbon, and for Ni(II)-citrate, the maximum was 1.3 mg per gram of carbon. For the EDTA complexes, the maximum removal was 2.1 mg of Cu(II)-EDTA complex per gram of carbon, 6.9 mg of Zn(II)-EDTA complex per gram of carbon, and 3.2 mg of Ni(II)-EDTA complex per gram of carbon.

  14. Copper-chelating azides for efficient click conjugation reactions in complex media.

    Science.gov (United States)

    Bevilacqua, Valentina; King, Mathias; Chaumontet, Manon; Nothisen, Marc; Gabillet, Sandra; Buisson, David; Puente, Céline; Wagner, Alain; Taran, Frédéric

    2014-06-02

    The concept of chelation-assisted copper catalysis was employed for the development of new azides that display unprecedented reactivity in the copper(I)-catalyzed azide-alkyne [3+2] cycloaddition (CuAAC) reaction. Azides that bear strong copper-chelating moieties were synthesized; these functional groups allow the formation of azide copper complexes that react almost instantaneously with alkynes under diluted conditions. Efficient ligation occurred at low concentration and in complex media with only one equivalent of copper, which improves the biocompatibility of the CuAAC reaction. Furthermore, such a click reaction allowed the localization of a bioactive compound inside living cells by fluorescence measurements.

  15. Emulsifier type, metal chelation and pH affect oxidative stability of n-3-enriched emulsions

    DEFF Research Database (Denmark)

    Haahr, Anne-Mette; Jacobsen, Charlotte

    2008-01-01

    Recent research has shown that the oxidative stability of oil-in-water emulsions is affected by the type of surfactant used as emulsifier. The aim of this study was to evaluate the effect of real food emulsifiers as well as metal chelation by EDTA and pH on the oxidative stability of a 10% n-3...... to their ability to chelate iron, scavenge free radicals, interfere with interactions between the lipid hydroperoxides and iron as well as to form a physical harrier around the oil droplets....

  16. DCCP and DICP: Construction and Analyses of Databases for Copper- and Iron-Chelating Proteins

    Institute of Scientific and Technical Information of China (English)

    Hao Wu; Yan Yang; Sheng-Juan Jiang; Ling-Ling Chen; Hai-Xia Gao; Qing-Shan Fu; Feng Li; Bin-Guang Ma; Hong-Yu Zhang

    2005-01-01

    Copper and iron play important roles in a variety of biological processes, especially when being chelated with proteins. The proteins involved in the metal binding,transporting and metabolism have aroused much interest. To facilitate the study on this topic, we constructed two databases (DCCP and DICP) containing the known copper- and iron-chelating proteins, which are freely available from the website http:∥sdbi.sdut.edu.cn/en. Users can conveniently search and browse all of the entries in the databases. Based on the two databases, bioinformatic analyses were performed, which provided some novel insights into metalloproteins.

  17. Chelation behavior of various flavonols and transfer of flavonol-chelated zinc(II) to alanylaspartic dipeptide: A PCM/DFT investigation

    Science.gov (United States)

    Yasarawan, Nuttawisit; Thipyapong, Khajadpai; Ruangpornvisuti, Vithaya

    2016-03-01

    Alanylaspartic dipeptide (AlaAsp) and zinc(II)-flavonol complex could represent a metal-binding site in proteins and a metal-ion releasing agent, respectively. Chelation of zinc(II) by either AlaAsp or flavonol ligands in aqueous solution has been examined using DFT methods with polarizable continuum model (PCM/DFT). Coordination geometry, complexation stoichiometry, coordination bond strength, preferable metal-binding site on ligands and effect of water coordination on the stability of complexes have been addressed. In several cases, the long-range corrected density functional CAM-B3LYP allows the most accurate prediction of both structural and spectroscopic data. The preferential transfer of flavonol-chelated zinc(II) to AlaAsp under solvation is attainable through the ligand-exchange reaction. The energy barrier of such reaction is significantly dependent on the degree of hydrogen bonding within the transition state. In summary, either hydroxylation or methoxylation at particular positions on the 3-hydroxyflavone backbone significantly affects the reactivity of flavonol chelates in the metal-ion transfer.

  18. [La(UO2)V2O7][(UO2)(VO4)] the first lanthanum uranyl-vanadate with structure built from two types of sheets based upon the uranophane anion-topology

    Science.gov (United States)

    Mer, A.; Obbade, S.; Rivenet, M.; Renard, C.; Abraham, F.

    2012-01-01

    The new lanthanum uranyl vanadate divanadate, [La(UO2)V2O7][(UO2)(VO4)] was obtained by reaction at 800 °C between lanthanum chloride, uranium oxide (U3O8) and vanadium oxide (V2O5) and the structure was determined from single-crystal X-ray diffraction data. This compound crystallizes in the orthorhombic system with space group P212121 and unit-cell parameters a=6.9470(2) Å, b=7.0934(2) Å, c=25.7464(6) Å, V=1268.73(5) Å3, Z=4. A full matrix least-squares refinement yielded R1=0.0219 for 5493 independent reflections. The crystal structure is characterized by the stacking of uranophane-type sheets [(UO2)(VO4)]-∞2 and double layers [La(UO2)(V2O7)]+∞2 connected through La-O bonds involving the uranyl oxygen of the uranyl-vanadate sheets. The double layers result from the connection of two [La(UO2)(VO4)2]-∞2 sheets derived from the uranophane anion-topology by replacing half of the uranyl ions by lanthanum atoms and connected through the formation of divanadate entities.

  19. What Is Antiphospholipid Antibody Syndrome?

    Science.gov (United States)

    ... page from the NHLBI on Twitter. What Is Antiphospholipid Antibody Syndrome? Antiphospholipid (AN-te-fos-fo-LIP-id) antibody ... weeks or months. This condition is called catastrophic antiphospholipid syndrome (CAPS). People who have APS also are at ...

  20. Red Blood Cell Antibody Identification

    Science.gov (United States)

    ... ID, RBC; RBC Ab ID Formal name: Red Blood Cell Antibody Identification Related tests: Direct Antiglobulin Test ; RBC ... I should know? How is it used? Red blood cell (RBC) antibody identification is used as a follow- ...

  1. Lupus anticoagulants and antiphospholipid antibodies

    Science.gov (United States)

    ... this page: //medlineplus.gov/ency/article/000547.htm Lupus anticoagulants and antiphospholipid antibodies To use the sharing features on this page, please enable JavaScript. Lupus anticoagulants are antibodies against substances in the lining ...

  2. Anti-smooth muscle antibody

    Science.gov (United States)

    ... gov/ency/article/003531.htm Anti-smooth muscle antibody To use the sharing features on this page, please enable JavaScript. Anti-smooth muscle antibody is a blood test that detects the presence ...

  3. Antibody Engineering and Therapeutics Conference

    OpenAIRE

    Larrick, James W; Parren, Paul WHI; Huston, James S; Plückthun, Andreas; Bradbury, Andrew; Tomlinson, Ian M; Chester, Kerry A.; Burton, Dennis R.; Adams, Gregory P.; Weiner, Louis M.; Scott, Jamie K.; Alfenito, Mark R; Veldman, Trudi; Reichert, Janice M.

    2013-01-01

    The Antibody Engineering and Therapeutics conference, which serves as the annual meeting of The Antibody Society, will be held in Huntington Beach, CA from Sunday December 8 through Thursday December 12, 2013. The scientific program will cover the full spectrum of challenges in antibody research and development, and provide updates on recent progress in areas from basic science through approval of antibody therapeutics. Keynote presentations will be given by Leroy Hood (Institute of System Bi...

  4. Structural Characterization of Peptide Antibodies

    DEFF Research Database (Denmark)

    Chailyan, Anna; Marcatili, Paolo

    2015-01-01

    The role of proteins as very effective immunogens for the generation of antibodies is indisputable. Nevertheless, cases in which protein usage for antibody production is not feasible or convenient compelled the creation of a powerful alternative consisting of synthetic peptides. Synthetic peptides...... can be modified to obtain desired properties or conformation, tagged for purification, isotopically labeled for protein quantitation or conjugated to immunogens for antibody production. The antibodies that bind to these peptides represent an invaluable tool for biological research and discovery...

  5. Effects of nutrient trace metal speciation on algal growth in the presence of the chelator [S,S]-EDDS

    NARCIS (Netherlands)

    Schowanek, D.; McAvoy, D.; Versteeg, D.; Hanstveit, A.

    1996-01-01

    This study tests the hypothesis that the apparent toxicity of strong chelators in standard algal growth inhibition tests (e.g. method OECD 201, EC C.3., ISO 8692) is related to essential trace metal bioavailability. This hypothesis was investigated for the chelator [S,S]-ethylene diamine disuccinate

  6. Reactivity and molecular modeling of new solvatochromic mixed-ligand copper(II) chelates of 2-acetylbutyrolactone and dinitrogen bases.

    Science.gov (United States)

    Taha, A; Adly, Omima M I; Shebl, Magdy

    2015-04-01

    A new series of solvatochromic mononuclear mixed ligand chelates with the general formula: Cu(AcBL)(L)X; where AcBL=2-acetylbutyrolactonate, L=N,N,N',N'-tetramethylethylenediamine (Me4en), N,N,N',N'-tetramethylpropylene diamine (Me4pn), 1,10-phenanthroline (Phen) or 2,2'-bipyridyl (Bipy) and X=ClO4-, NO3- or Br- have been synthesized and characterized by the analytical and spectral methods, as well as magnetic and molar conductance measurements. The d-d absorption bands of Me4en-chelates as Nujol mulls or weak donor solvents solutions revealed square-planar, distorted octahedral and/or distorted trigonal bipyramid geometries for the perchlorate, nitrate and bromide chelates, respectively. However, an octahedral structure is identified for chelates in strong donor solvents. Perchlorate chelates show a remarkable color change from violet to green as the Lewis basicity of the donor solvent increases, whereas bromide chelates are mainly affected by the Lewis acidity of solvent. Specific and non-specific interactions of solvent molecules with the chelates were investigated on the basis of unified solvation model. Structural parameters of the free ligands and their Cu(II)-chelates have been calculated on the basis of semiempirical PM3 level and correlated with the experimental data.

  7. Extraction of Micronutrient Metals from Peat-based Media Using Various Chelate-ligand and Iron-source Extractants

    Science.gov (United States)

    Objectives of the study were to determine effects of chelate-ligand (experiment 1) and iron-source (experiment 2) unbuffrered extractant solutions on substrate pH and Cu, Fe, Mn, and Zn extraction from peat-based media. Chelate-ligand extractants consisted of 5 mM solutions of ethylenediaminedisucc...

  8. Nanoparticle-chelator conjugates as inhibitors of amyloid-beta aggregation and neurotoxicity: a novel therapeutic approach for Alzheimer disease.

    Science.gov (United States)

    Liu, Gang; Men, Ping; Kudo, Wataru; Perry, George; Smith, Mark A

    2009-05-22

    Oxidative stress and amyloid-beta are considered major etiological and pathological factors in the initiation and promotion of neurodegeneration in Alzheimer disease (AD). Insomuch as causes of such oxidative stress, transition metals, such as iron and copper, which are found in high concentrations in the brains of AD patients and accumulate specifically in the pathological lesions, are viewed as key contributors to the altered redox state. Likewise, the aggregation and toxicity of amyloid-beta is dependent upon transition metals. As such, chelating agents that selectively bind to and remove and/or "redox silence" transition metals have long been considered as attractive therapies for AD. However, the blood-brain barrier and neurotoxicity of many traditional metal chelators has limited their utility in AD or other neurodegenerative disorders. To circumvent this, we previously suggested that nanoparticles conjugated to iron chelators may have the potential to deliver chelators into the brain and overcome such issues as chelator bioavailability and toxic side-effects. In this study, we synthesized a prototype nanoparticle-chelator conjugate (Nano-N2PY) and demonstrated its ability to protect human cortical neurons from amyloid-beta-associated oxidative toxicity. Furthermore, Nano-N2PY nanoparticle-chelator conjugates effectively inhibited amyloid-beta aggregate formation. Overall, this study indicates that Nano-N2PY, or other nanoparticles conjugated to metal chelators, may provide a novel therapeutic strategy for AD and other neurodegenerative diseases associated with excess transition metals.

  9. Characterization of radionuclide-chelating agent complexes found in low-level radioactive decontamination waste. Literature review

    Energy Technology Data Exchange (ETDEWEB)

    Serne, R.J.; Felmy, A.R.; Cantrell, K.J.; Krupka, K.M.; Campbell, J.A.; Bolton, H. Jr.; Fredrickson, J.K. [Pacific Northwest National Lab., Richland, WA (United States)

    1996-03-01

    The US Nuclear Regulatory Commission is responsible for regulating the safe land disposal of low-level radioactive wastes that may contain organic chelating agents. Such agents include ethylenediaminetetraacetic acid (EDTA), diethylenetriaminepentaacetic acid (DTPA), picolinic acid, oxalic acid, and citric acid, and can form radionuclide-chelate complexes that may enhance the migration of radionuclides from disposal sites. Data from the available literature indicate that chelates can leach from solidified decontamination wastes in moderate concentration (1--100 ppm) and can potentially complex certain radionuclides in the leachates. In general it appears that both EDTA and DTPA have the potential to mobilize radionuclides from waste disposal sites because such chelates can leach in moderate concentration, form strong radionuclide-chelate complexes, and can be recalcitrant to biodegradation. It also appears that oxalic acid and citric acid will not greatly enhance the mobility of radionuclides from waste disposal sites because these chelates do not appear to leach in high concentration, tend to form relatively weak radionuclide-chelate complexes, and can be readily biodegraded. In the case of picolinic acid, insufficient data are available on adsorption, complexation of key radionuclides (such as the actinides), and biodegradation to make definitive predictions, although the available data indicate that picolinic acid can chelate certain radionuclides in the leachates.

  10. Study on Chelating Resins XXXI Syntheses and Adsorption Properties of a New Type of Bead Resins Containing S and N

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    A new type of bead crosslinked chelating resins containing coordinate atoms N and S were synthesized by the reaction of polyethyleneimine with chloromethylthiirane in suitable sovent at temperature of 2080C. These chelating resins exhibited excellent adsorption properties for precious metal ions.

  11. Iron chelators do not reduce cold-induced cell injury in the isolated perfused rat kidney model.

    NARCIS (Netherlands)

    Bartels-Stringer, M.; Wetzels, J.F.M.; Wouterse, A.C.; Steenbergen, E.; Russel, F.G.M.; Kramers, C.

    2005-01-01

    BACKGROUND: In vitro, cold-induced injury is an important contributor to renal tubular cell damage. It is mediated by iron-dependent formation of reactive oxygen species and can be prevented by iron chelation. We studied whether iron chelators can prevent cold-induced damage in the isolated perfused

  12. Synthetic peptides for antibody production

    NARCIS (Netherlands)

    Zegers, N.D.

    1995-01-01

    Synthetic peptides are useful tools for the generation of antibodies. The use of antibodies as specific reagents in inununochemical assays is widely applied. In this chapter, the application of synthetic peptides for the generation of antibodies is described. The different steps that lead to the uni

  13. Infrared Multiphoton Dissociation Spectroscopy of a Gas-Phase Complex of Uranyl and 3-Oxa-Glutaramide: An Extreme Red-Shift of the [O=U=O]²⁺ Asymmetric Stretch

    Energy Technology Data Exchange (ETDEWEB)

    Gibson, John K.; Hu, Hanshi; Van Stipdonk, Michael J.; Berden, Giel; Oomens, Jos; Li, Jun

    2015-04-09

    The gas-phase complex UO₂(TMOGA)₂²⁺ (TMOGA = tetramethyl-3-oxa-glutaramide) prepared by electrospray ionization was characterized by infrared multiphoton dissociation (IRMPD) spectroscopy. The IRMPD spectrum from 700–1800 cm⁻¹ was interpreted using a computational study based on density functional theory. The predicted vibrational frequencies are in good agreement with the measured values, with an average deviation of only 8 cm⁻¹ (<1%) and a maximum deviation of 21 cm⁻¹ (<2%). The only IR peak assigned to the linear uranyl moiety was the asymmetric ν₃ mode, which appeared at 965 cm⁻¹ and was predicted by DFT as 953 cm⁻¹. This ν₃ frequency is red-shifted relative to bare uranyl, UO₂²⁺, by ca. 150 cm⁻¹ due to electron donation from the TMOGA ligands. Based on the degree of red-shifting, it is inferred that two TMOGA oxygen-donor ligands have a greater effective gas basicity than the four monodentate acetone ligands in UO₂(acetone)₄²⁺. The uranyl ν₃ frequency was also computed for uranyl coordinated by two TMGA ligands, in which the central Oether of TMOGA has been replaced by CH₂. The computed ν₃ for UO₂(TMGA)₂²⁺, 950 cm⁻¹, is essentially the same as that for UO₂(TMOGA)₂²⁺, suggesting that electron donation to uranyl from the Oether of TMOGA is minor. The computed ν₃ asymmetric stretching frequencies for the three actinyl complexes, UO₂(TMOGA)₂²⁺, NpO₂(TMOGA)₂²⁺ and PuO₂(TMOGA)₂²⁺, are comparable. This similarity is discussed in the context of the relationship between ν₃ and intrinsic actinide-oxygen bond energies in actinyl complexes.

  14. SYNTHESIS AND MESOMORPHIC PROPERTIES OF PALLADIUM CHELATES OF LIQUID CRYSTAL POLYSILOXANE WITH β-DIKETONE-BASED SIDE CHAINS

    Institute of Scientific and Technical Information of China (English)

    ZHOU Zhaohui; DAI Daorong; ZHANG Rongben

    1992-01-01

    A new type of palladium chelate of β-diketone-based side chain liquid crystal polysiloxane(Pd-DKLCP) has been synthesized by chelation reaction of palladium dichloride with polymeric ligand, β-diketone polysiloxane (DKLCP), using THF as solvent at R .T.. The Pd-chelation results in greatly increasing the phase transition temperature TK and the enthalpy change AHK from crystal to liquid crystal state and making the temperature range of LC state AT (A T=Tc1- TK) widened.All these chelates Pd-DKLCP's do not show TCl until decomposition at 205 ℃. It is noteworthy that the Pd-chelation can exert more positive effect on the mesomorphic behaviour of the polymer ligand than the counterpart Cu-DKLCP does. It is probable due to the bigger size of disc-like mesogen formed from β-diketone and Pd +2 ion with 4d orbital.

  15. Modelling chelate-Induced phytoextraction: functional models predicting bioavailability of metals in soil, metal uptake and shoot biomass

    Directory of Open Access Journals (Sweden)

    Pasqualina Sacco

    Full Text Available Chelate-induced phytoextraction of heavy metals from contaminated soils requires special care to determine, a priori, the best method of chelate application, in terms of both dose and timing. In fact, the chelate dose must assure the bioavailability of the metal to the plant without increasing leaching risk and giving toxic effects. Three mathematical models are here proposed for usefully interpreting the processes taking place: a increased soil bioavailability of metals by chelants; b metal uptake by plants; c variation in plant biomass. The models are implemented and validated using data from pot and lysimeter trials. Both the chelate dose and the time elapsed since its application affected metal bioavailability and plant response. Contrariwise, the distribution strategy (single vs. split application seems to produce significant differences both in plant growth and metal uptake, but not in soil metal bioavailability. The proposed models may help to understand and predict the chelate dose – effect relationship with less experimental work.

  16. Effect of chelating agent on oxidation rate of aniline in ferrous ion activated persulfate system at neutral pH

    Institute of Scientific and Technical Information of China (English)

    张永清; 谢晓芳; 黄少斌; 梁海云

    2014-01-01

    In the interest of accelerating aniline degradation, Fe2+and chelated Fe2+activated persulfate oxidations were investigated in neutral pH condition. Three kinds of chelating agents were selected including citric acid, oxalic acid and ethylenediamine tetraaceatate (EDTA) to maintain available Fe2+. The results indicate that the concentration of chelating agent and ferrous ion didn’t follow a linear relationship with the degradation rate of aniline. A 1/1 ratio of chelating agent/Fe2+results in a higher degradation rate compared to the results by other ratios. The oxidation enhancement factor using oxalic acid was found to be relatively low. In contrast, citric acid is more suitable chelating agent in the ferrous iron activated persulfate system and aniline exhibits a highest degradation with a persulfate/Fe2+/citric acid/aniline molar ratio of 50/25/25/1 compared to other molar ratios.

  17. Selection of Chelated Fe (III)/Fe (II) Catalytic Oxidation Agents for Desulfurization Based on Iron Complexation Method

    Institute of Scientific and Technical Information of China (English)

    Luo Ying; Liu Youzhi; Qi Guisheng; Guo Huidong; Zhu Zhengfeng

    2014-01-01

    Optimization of factors inlfuencing the experiments on reactions involving 8 different chelating agents and sol-uble Fe (III)/Fe (II) salts was carried out to yield chelated iron complexes. A combination of optimized inlfuencing factors has resulted in a Fe chelating capacity of the iron-based desulfurization solution to be equal to 6.83-13.56 g/L at a redox potential of 0.185-0.3. The desulfurization performance of Fe (III)/Fe (II) chelating agents was investigated on a simulated sulfur-containing industrial gas composed of H2S and N2 in a cross-lfow rotating packed bed. Test results have revealed that the proposed iron-based desulfurization solution showed a sulfur removal efifciency of over 99%along with a Fe chelating capacity exceeding 1.35 g/L. This desulfurization technology which has practical application prospect is currently in the phase of commercial scale-up study.

  18. Chelating agents improve enzymatic solubilization of pectinaceous co-processing streams

    DEFF Research Database (Denmark)

    Ravn, Helle Christine; Meyer, Anne S.

    2014-01-01

    /substrate] at 60 °C, pH 6.0 for 1 min. Characterization of the released fractions demonstrated a significantly improved effect of chelating agents for polysaccharide solubilization from FiberBind 400, PUF, and citrus peel, whereas only low amounts of polysaccharides were solubilized from the sugar beet pulp...

  19. Kinetic Studies on Forming Iso-nuclear -type Chelates of Rare Earths with p-Sulphoaminobromophosphonazo

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    The kinetic behavior of forming the iso-nuclear b -type chelates of rare earth ions (RE3+) with p-sulphoaminobromophosphonazo (BPA-pSN) in ClCH2COOH-CH3COONa buffer solutions were studied by a spectrophotometric method.

  20. The impact of succimer chelation on blood cadmium in children with background exposures: a randomized trial.

    Science.gov (United States)

    Cao, Yang; Chen, Aimin; Bottai, Matteo; Caldwell, Kathleen L; Rogan, Walter J

    2013-08-01

    Succimer lowers blood lead concentrations in children, and the structure of succimer chelates of lead and cadmium are similar. Using blood samples from a randomized trial of succimer for lead poisoning, however, we found that succimer did not lower blood cadmium in children with background exposure.

  1. Metal Ions Extraction with Glucose Derivatives as Chelating Reagents in Supercritical Carbon Dioxide

    Institute of Scientific and Technical Information of China (English)

    Guo Chen YANG; Hai Jian YANG

    2006-01-01

    A series of glucose derivatives have been used as chelating reagents to extract metal ions in supercritical carbon dioxide. With perfluoro-1-octanesulfonic acid tetraethylammonium salt as additive, glucose derivatives were selective for Sr2+ and Pb2+ extraction in supercritical carbon dioxide.

  2. Use of organometallic chelates in broiler diet: effect on the performance and bone structure. Preliminary results

    Directory of Open Access Journals (Sweden)

    Biagina Chiofalo

    2010-01-01

    Full Text Available On 26,000 Ross 508 broiler chickens (two groups of 13,000 per pen the effect of dietary substitution with in organic trace minerals or organometallic chelates on performances and bones tructure c trace minerals or organometallic chelates on performances and bone structure was studied. Treatments consisted of a commercial diet integrated with 0.5% of a vitamin-mineral premix containing inorganic trace minerals (CTR or organometallic chelates (MHA using Methionine Hydroxy Analog. Production performance was measured during the 52 d trial period and bone structure was evalu- ated at the slaughter (52 d. Significant (P=0.038 higher values were observed in the finishing period (41 to 52 d for the body weight of the treated group (3560 g vs. 3358 g. The same trend was observed for the ADG (MHA 87.6 g/d vs. CTR 71 g/d; P<0.05. Concerning ash percentage significant higher values were observed in the CTR group for femur (49.01% vs. 51.45%; P<0.01 and tibia (53.87% vs. 49.79%; P<0.001; femur showed also higher values for bone radiopacity (MHA 0.21 px vs. CTR 0.26 px; P=0.035. MHA group showed significant higher value for morphometric measures of the femur and tibia. Results suggest that organometallic chelates can be included in the diet without compromising broiler performance.

  3. Catechol-Bisphosphonate Conjugates:New Potential Chelating Agents for Metal Intoxication Therapy

    Institute of Scientific and Technical Information of China (English)

    Guang Yu XU; Chun Hao YANG; Bo LIU; Xi Han WU; Yu Yuan XIE

    2004-01-01

    In a quest for better chelating therapy drugs for the treatment of intoxication by Fe, Al, or actinides, two new series of mixed catechol-bisphosphonate through amide linkage were synthesized.Benzyl group was used as protecting group to avoid the breakage of amide by acid hydrolysis or imcomplete reaction in silylation-dealkylation using bromotrimethylsilane.

  4. Modern Chemistry Techniques Applied to Metal Behavior and Chelation in Medical and Environmental Systems ? Final Report

    Energy Technology Data Exchange (ETDEWEB)

    Sutton, M; Andresen, B; Burastero, S R; Chiarappa-Zucca, M L; Chinn, S C; Coronado, P R; Gash, A E; Perkins, J; Sawvel, A M; Szechenyi, S C

    2005-02-03

    This report details the research and findings generated over the course of a 3-year research project funded by Lawrence Livermore National Laboratory (LLNL) Laboratory Directed Research and Development (LDRD). Originally tasked with studying beryllium chemistry and chelation for the treatment of Chronic Beryllium Disease and environmental remediation of beryllium-contaminated environments, this work has yielded results in beryllium and uranium solubility and speciation associated with toxicology; specific and effective chelation agents for beryllium, capable of lowering beryllium tissue burden and increasing urinary excretion in mice, and dissolution of beryllium contamination at LLNL Site 300; {sup 9}Be NMR studies previously unstudied at LLNL; secondary ionization mass spec (SIMS) imaging of beryllium in spleen and lung tissue; beryllium interactions with aerogel/GAC material for environmental cleanup. The results show that chelator development using modern chemical techniques such as chemical thermodynamic modeling, was successful in identifying and utilizing tried and tested beryllium chelators for use in medical and environmental scenarios. Additionally, a study of uranium speciation in simulated biological fluids identified uranium species present in urine, gastric juice, pancreatic fluid, airway surface fluid, simulated lung fluid, bile, saliva, plasma, interstitial fluid and intracellular fluid.

  5. Affinity purification of copper-chelating peptides from sunflower protein hydrolysates.

    Science.gov (United States)

    Megías, Cristina; Pedroche, Justo; Yust, Maria M; Girón-Calle, Julio; Alaiz, Manuel; Millan, Francisco; Vioque, Javier

    2007-08-08

    Copper-chelating peptides were purified from sunflower protein hydrolysates by affinity chromatography using immobilized copper. A variety of protein hydrolysates were obtained by incubation with the proteases Alcalase and Flavourzyme for different periods of time. Chelating activity was indirectly determined by measuring the inhibitory effect of hydrolysates on the oxidation of beta-carotene by copper. Copper-binding peptides purified from the two hydrolysates that inhibited oxidation by copper the most contained 25.4 and 42.0% histidine and inhibited beta-carotene oxidation 8 and 3 times more than the original hydrolysates, which had 2.4 and 2.6% histidine, respectively. Thus, histidine content is not the only factor involved in antioxidant activity, and probably other factors such as peptide size and amino acid sequence are also important. This work shows that affinity chromatography can be used for the purification of copper-chelating peptides and probably other metals of nutritional interest such as calcium, iron, and zinc. In addition to their antioxidant potential, chelating peptides are of nutritional interest because they increase bioavailability of minerals.

  6. Spectroscopy, modeling and computation of metal chelate solubility in supercritical CO{sub 2}

    Energy Technology Data Exchange (ETDEWEB)

    J. F. Brennecke; M. A. Stadtherr

    1999-12-10

    The overall objectives of this project were to gain a fundamental understanding of the solubility and phase behavior of metal chelates in supercritical CO{sub 2}. Extraction with CO{sub 2} is an excellent way to remove organic compounds from soils, sludges and aqueous solutions, and recent research has demonstrated that, together with chelating agents, it is a viable way to remove metals, as well. In this project the authors sought to gain fundamental knowledge that is vital to computing phase behavior, and modeling and designing processes using CO{sub 2} to separate organics and metal compounds from DOE mixed wastes. The overall program was a comprehensive one to measure, model and compute the solubility of metal chelate complexes in supercritical CO{sub 2} and CO{sub 2}/cosolvent mixtures. Through a combination of phase behavior measurements, spectroscopy and the development of a new computational technique, the authors have achieved a completely reliable way to model metal chelate solubility in supercritical CO{sub 2} and CO{sub 2}/co-contaminant mixtures. Thus, they can now design and optimize processes to extract metals from solid matrices using supercritical CO{sub 2}, as an alternative to hazardous organic solvents that create their own environmental problems, even while helping in metals decontamination.

  7. Design and Application of Latent Olefin Metathesis Catalysts Featuring S-Chelating Alkylidene Ligands

    Science.gov (United States)

    Szadkowska, Anna; Grela, Karol

    This review article is devoted to recent advances in the design and application of so-called “dormant” or “latent” ruthenium olefin metathesis catalysts bearing S-chelating alkylidene ligands. Selected ruthenium complexes containing S-donor ligands, which possess controllable initiation behaviour are presented. Applications of these complexes in olefin metathesis are described.

  8. The Mechanism of Cumene Peroxidation Catalyzed by Cobalt(Ⅱ)-Chelated Copolymer

    Institute of Scientific and Technical Information of China (English)

    Cheng-Chien Wang; Hui-Chun Chen; Chuh-Yean Chen; Chuh-Yung Chen

    2005-01-01

    @@ 1Introduction The functionalised polymers, especially for chelating polymer, have been employed to considerable effects in organic synthesis for several decades. The use of polymer groups as ligands permits the ligand surroundings to be varied and regulation of the catalytic properties of the complexes because of the flexibility of the polymer chains, their ability to adopt various conformations, and the possibility of creating various spatial distributions of metal centers immobilized on the polymer chains[1,2]. In our recently studies[3-5], the chelating copolymer with imino-diacetic acid chelating group in the polymer side chain was manufactured, and which can increase effectively amount of the chelating group within the polymer. Meanwhile, the high catalysis performance in organic synthesis had also been proved via benzaldehyde and cumene peroxidation. For cumene peroxidation,it is hardly to find such a simple catalyst with high conversion and selectivity due to hydroperoxide decomposition by a radical mechanism. The cumene peroxidation by catalyst system and its reaction mechanism as well as the kinetic study are popularly investigated object for many researchers[6-9]. However, the reaction mechanism still does not clear owing to the by-products will be produced following the different catalysts used.

  9. [Remediation of Cu-Pb-contaminated loess soil by leaching with chelating agent and biosurfactant].

    Science.gov (United States)

    Liu, Xia; Wang, Jian-Tao; Zhang, Meng; Wang, Li; Yang, Ya-Ti

    2013-04-01

    Because of its strong chelation, solubilization characteristics, the chelating agents and biosurfactant are widely used in remediation of heavy metals and organic contaminated soils. Ethylenediamine tetraacetic acid (EDTA), citric acid (CIT) and dirhamnolipid (RL2) were selected as the eluent. Batch experiments and column experiments were conducted to investigate the leaching effect of the three kinds of eluent, as well as the mixture of biosurfactant and chelating agent for Cu, Pb contaminated loess soil. The results showed that the leaching efficiencies of different eluent on Cu, Pb contaminated loess soil followed the sequence of EDTA > CIT > RL2. At an eluent concentration of 0.02 mol x L(-1), the Cu leaching efficiency was 62.74% (EDTA), 52.28% (CIT) and 15.35% (RL2), respectively; the Pb leaching efficiency was 96.10% (EDTA), 23.08% (CIT) and 14.42% (RL2), respectively. When the concentration of RL2 was 100 CMC, it had synergistic effects on the other two kinds of chelating agent in Cu leaching, and when the concentration of RL2 was 200 CMC, it had antagonism effects. The effect of RL2 on EDTA in Pb leaching was similar to that in Cu leaching. Pb leaching by CIT was inhibited in the presence of RL2. EDTA and CIT could effectively remove Cu and Pb in exchangeable states, adsorption states, carbonate salts and organic bound forms; RL2 could effectively remove Cu and Pb in exchangeable and adsorbed states.

  10. Thermodynamic Analysis of Allosteric and Chelate Cooperativity in Di- and Trivalent Ammonium/Crown-Ether Pseudorotaxanes.

    Science.gov (United States)

    Nowosinski, Karol; von Krbek, Larissa K S; Traulsen, Nora L; Schalley, Christoph A

    2015-10-16

    A detailed thermodynamic analysis of the axle-wheel binding in di- and trivalent secondary ammonium/[24]crown-8 pseudorotaxanes is presented. Isothermal titration calorimetry (ITC) data and double mutant cycle analyses reveal an interesting interplay of positive as well as negative allosteric and positive chelate cooperativity thus providing profound insight into the effects governing multivalent binding in these pseudorotaxanes.

  11. Ruthenium(II) and iridium(III) complexes featuring NHC-sulfonate chelate.

    Science.gov (United States)

    Rajaraman, A; Sahoo, A R; Hild, F; Fischmeister, C; Achard, M; Bruneau, C

    2015-10-28

    Three new complexes bearing a chelating (κ(2)C,O) NHC-SO3 ligand have been prepared. An original method for the synthesis of the imidazolium-sulfonate NHC precursor is described. The 5-membered ruthena- and irida-cycle containing complexes were fully characterized and evaluated in a series of catalytic transformations involving hydrogen auto-transfer processes.

  12. The effects of Fe-chelate type and PH on substrate grown roses

    NARCIS (Netherlands)

    Voogt, W.; Sonneveld, C.

    2009-01-01

    Substrate grown roses appear to be susceptible to chlorosis, which indicates problems with Fe or Mn uptake and hence yield reduction. In common practice this problem is often treated by the addition of extra Fe-chelate, or the use of Fe-EDDHA instead of Fe-DTPA. In previous tests, it was shown that

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

    Science.gov (United States)

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

    2015-12-21

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

  14. Essential trace metal excretion from rats with lead exposure and during chelation therapy.

    Science.gov (United States)

    Victery, W; Miller, C R; Goyer, R A

    1986-02-01

    Urinary excretion of lead, zinc, calcium, magnesium, iron, copper, sodium, and potassium was measured in rats daily for 1 week after a 6-week exposure to 10,000 micrograms/ml lead in drinking water. Beginning on the third day, half of the lead-exposed and control rats were injected intraperitoneally with calcium disodium ethylenediaminetetraacetate (EDTA) daily for 3 days. Whole blood, plasma, and kidney metal concentrations were determined from samples obtained at the end of the experiment. Exposure to lead increased urinary excretion, not only of lead, but also of calcium, magnesium, zinc, copper, and iron. Excretion of sodium and potassium was not altered. Chelation therapy further increased excretion of lead, zinc, copper, and iron, but not magnesium. The increase in calcium excretion during chelation treatment (beyond that resulting from lead exposure per se) was accounted for by the Ca content of CaNa2-EDTA. EDTA treatment increased renal concentration of zinc but lowered renal concentration of lead, copper, and iron. These multimetal alterations may have implications for essential metal supplementation, particularly zinc, in persons being given chelation agents for excess lead exposure and in infants and children with low-level lead exposure not necessarily requiring chelation therapy.

  15. Lanthanide Chelates as Bilayer Alignment Tools in NMR Studies of Membrane-Associated Peptides

    Science.gov (United States)

    Prosser, R. S.; Bryant, H.; Bryant, R. G.; Vold, Regitze R.

    1999-12-01

    Theequimolar complex, consisting of the lipid-like, amphiphilic chelating agent 1,11-bis[distearylamino]-diethylenetriamine pentaacetic acid (DTPA-18) and Tm3+, is shown by deuterium (2H) NMR to be useful in aligning bicelle-like model membranes, consisting of dimyristoylphosphatidylcholine (DMPC) and dihexanoylphosphatidylcholine (DHPC). As shown previously (1996, R. S. Prosser et al., J. Am. Chem. Soc. 118, 269-270), in the absence of chelate, the lanthanide ions bind loosely with the lipid phosphate groups and confer the membrane with a sufficient positive magnetic anisotropy to result in parallel alignment (i.e., average bilayer normal along the field). Apparently, DTPA-18 sequesters the lanthanide ions and inserts into the phospholipid bilayer in such a manner that bilayer morphology is preserved over a wide temperature range (35-70°C). The inherent paramagnetic shifts and line broadening effects are illustrated by 2H NMR spectra of the membrane binding peptide, Leu-enkephalin (Lenk-d2, Tyr-(Gly-d2)-Gly-Phe-Leu-OH), in the presence of varying concentrations of Tm3+, and upon addition of DTPA-18. Two conclusions could be drawn from this study: (1) The addition of Tm3+ to the bicelle system is consistent with a conformational change in the surface associated peptide, and this effect is shown to be reversed by addition of the chelate, and (2) The paramagnetic shifts are shown to be significantly reduced by addition of chelate.

  16. Comparison of the antibacterial activity of chelating agents using the agar diffusion method

    Science.gov (United States)

    The agar diffusion assay was used to examine antibacterial activity of 2 metal chelators. Concentrations of 0 to 40 mM of ethylenediaminetetraacetic acid (EDTA) and ethylenediamine-N,N’-disuccinic acid (EDDS) were prepared in 1.0 M potassium hydroxide (KOH). The pH of the solutions was adjusted to 1...

  17. Searching for new aluminium chelating agents: a family of hydroxypyrone ligands.

    Science.gov (United States)

    Toso, Leonardo; Crisponi, Guido; Nurchi, Valeria M; Crespo-Alonso, Miriam; Lachowicz, Joanna I; Mansoori, Delara; Arca, Massimiliano; Santos, M Amélia; Marques, Sérgio M; Gano, Lurdes; Niclós-Gutíerrez, Juan; González-Pérez, Josefa M; Domínguez-Martín, Alicia; Choquesillo-Lazarte, Duane; Szewczuk, Zbigniew

    2014-01-01

    Attention is devoted to the role of chelating agents in the treatment of aluminium related diseases. In fact, in spite of the efforts that have drastically reduced the occurrence of aluminium dialysis diseases, they so far constitute a cause of great medical concern. The use of chelating agents for iron and aluminium in different clinical applications has found increasing attention in the last thirty years. With the aim of designing new chelators, we synthesized a series of kojic acid derivatives containing two kojic units joined by different linkers. A huge advantage of these molecules is that they are cheap and easy to produce. Previous works on complex formation equilibria of a first group of these ligands with iron and aluminium highlighted extremely good pMe values and gave evidence of the ability to scavenge iron from inside cells. On these bases a second set of bis-kojic ligands, whose linkers between the kojic chelating moieties are differentiated both in terms of type and size, has been designed, synthesized and characterized. The aluminium(III) complex formation equilibria studied by potentiometry, electrospray ionization mass spectroscopy (ESI-MS), quantum-mechanical calculations and (1)H NMR spectroscopy are here described and discussed, and the structural characterization of one of these new ligands is presented. The in vivo studies show that these new bis-kojic derivatives induce faster clearance from main organs as compared with the monomeric analog.

  18. The iron chelator deferasirox protects mice from mucormycosis through iron starvation

    Science.gov (United States)

    Clinical and animal model data indicate that the presence of elevated available serum iron predisposes the host to mucormycosis. Here we demonstrate that deferasirox, an iron chelator recently approved for use in humans by the United States (US) Food and Drug Administration (FDA), is a highly effec...

  19. [Enhanced phytoextraction of heavy metal contaminated soil by chelating agents and auxin indole-3-acetic acid].

    Science.gov (United States)

    Zhou, Jian-min; Dang, Zhi; Chen, Neng-chang; Xu, Sheng-guang; Xie, Zhi-yi

    2007-09-01

    The environmental risk of chelating agents such as EDTA application to the heavy metals polluted soils and the stress on plant roots due to the abrupt increase metals concentration limit the wide commercial use of chelate-induced phytoextraction. Chelating agent ethylenediaminetetraacetic acid (EDTA) and nitrilotriacetic acid (NTA) and auxin indole-3-acetic acid (IAA) were used for enhancing heavy metals uptake from soils by Zea mays L. (corn) in pot experiments. The metals content in plant tissues was quantified using an inductively coupled plasma mass spectrometer (ICP-MS). The results showed that the combination of IAA and EDTA increased the biomass by about 40.0% and the contents of Cu, Zn, Cd and Pb in corn shoots by 27.0%, 26.8%, 27.5% and 32.8% respectively, as compared to those in EDTA treatment. While NTA&IAA treatment increased the biomass by about 29.9% and the contents of Cu, Zn, Cd and Pb in corn shoots by 31.8%, 27.6%, 17.0% and 26.9% respectively, as compared to those in NTA treatment. These results indicated that corn growth was promoted, and the biomass and the accumulation of heavy metals in plant shoots were increased significantly with the addition of IAA, which probably helps to change the cell membrane properties and the biomass distribution, resulting in the alleviation of the phytotoxicity of metals and the chelating agents.

  20. Comprehensive radiolabeling, stability, and tissue distribution studies of technetium-99m single amino acid chelates (SAAC).

    Science.gov (United States)

    Maresca, Kevin P; Hillier, Shawn M; Femia, Frank J; Zimmerman, Craig N; Levadala, Murali K; Banerjee, Sangeeta R; Hicks, Justin; Sundararajan, Chitra; Valliant, John; Zubieta, Jon; Eckelman, William C; Joyal, John L; Babich, John W

    2009-08-19

    Technetium tricarbonyl chemistry has been a subject of interest in radiopharmaceutical development over the past decade. Despite the extensive work done on developing chelates for Tc(I), a rigorous investigation of the impact of changing donor groups and labeling conditions on radiochemical yields and/or distribution has been lacking. This information is crucially important if these platforms are going to be used to develop molecular imaging probes. Previous studies on the coordination chemistry of the {M(CO)(3)}(+) core have established alkylamine, aromatic nitrogen heterocycles, and carboxylate donors as effective chelating ligands. These observations led to the design of tridentate ligands derived from the amino acid lysine. Such amino acid analogues provide a tridentate donor set for chelation to the metal and an amino acid functionality for conjugation to biomolecules. We recently developed a family of single amino acid chelates (SAAC) that serve this function and can be readily incorporated into peptides via solid-phase synthesis techniques. As part of these continuing studies, we report here on the radiolabeling with technetium-99m ((99m)Tc) and stability of a series of SAAC analogues of lysine. The complexes studied include cationic, neutral, and anionic complexes. The results of tissue distribution studies with these novel complexes in normal rats demonstrate a range of distribution in kidney, liver, and intestines.